Move everything into a new repo.

213 files changed, 4633 insertions, 0 deletions

diff --git a/userland/libc/Makefile b/userland/libc/Makefile
new file mode 100644
index 0000000..98d81d4
--- /dev/null
+++ b/userland/libc/Makefile
@@ -0,0 +1,26 @@
+CC="/home/anton/prj/osdev/sysroot/bin/i686-sb-gcc"
+AR="/home/anton/prj/osdev/sysroot/bin/i686-sb-ar"
+AS="/home/anton/prj/osdev/sysroot/bin/i686-sb-as"
+#CFLAGS = -ggdb -ffreestanding -O0 -Wall -Wextra -pedantic -mgeneral-regs-only -Wimplicit-fallthrough -I./include/ -static -fsanitize=shift,signed-integer-overflow,bounds
+CFLAGS = -ggdb -ffreestanding -O2 -Wall -pedantic -Wimplicit-fallthrough -I./include/ -static
+#BINS=c.a libc.o crt0.o malloc.o pty.o mmap.o
+OBJ=crt0.o libc.o malloc/malloc.o pty.o sys/mman/mmap.o memset.o assert.o stdio/snprintf.o stdio/vfprintf.o string/memcpy.o string/memcmp.o string/strcmp.o ubsan.o string/strcpy.o isspace.o stdio/puts.o stdio/putchar.o dirent/opendir.o dirent/readdir.o dirent/closedir.o unistd/getopt.o dirent/scandir.o dirent/alphasort.o stdio/printf.o stdio/vdprintf.o stdio/vprintf.o stdio/dprintf.o stdio/vprintf.o string/strlen.o string/strnlen.o stdio/stdin.o stdio/stdout.o stdio/stderr.o stdio/getchar.o stdio/fgetc.o arpa/inet/htons.o arpa/inet/htonl.o stdio/fread.o stdio/fwrite.o stdio/fopen.o stdio/fclose.o stdio/fseek.o ctype/isascii.o stdio/fprintf.o stdlib/atoi.o stdlib/strtol.o ctype/toupper.o ctype/tolower.o string/strcat.o string/strchr.o string/sscanf.o sys/stat/stat.o stdlib/getenv.o string/strrchr.o stdio/ftell.o stdio/tmpfile.o stdio/fgets.o stdio/feof.o stdio/fscanf.o stdio/ungetc.o string/strncmp.o stdio/fputc.o string/strncpy.o stdio/remove.o stdio/ferror.o stdio/fputs.o stdlib/rand.o stdlib/srand.o unistd/getpid.o stdlib/strtoul.o stdio/fflush.o stdlib/abort.o string/strcspn.o time/localtime.o time/time.o time/clock_gettime.o time/gmtime.o time/strftime.o string/strpbrk.o ctype/isdigit.o ctype/isalpha.o ctype/isxdigit.o ctype/ispunct.o stdio/setvbuf.o stdio/fileno.o stdio/putc.o stdio/sprintf.o stdlib/abs.o string/strspn.o stdlib/qsort.o string/memmove.o setjmp/longjmp.o setjmp/setjmp.o libgen/basename.o string/strdup.o string/strndup.o string/strlcpy.o stdlib/atexit.o stdio/open_memstream.o libgen/dirname.o unistd/unlink.o string/strstr.o string/strcasecmp.o string/strncasecmp.o stdlib/mkstemp.o string/strtok.o unistd/execvp.o unistd/_exit.o ctype/isalnum.o time/ctime_r.o stdlib/strtold.o sys/time/gettimeofday.o stdio/fgetpos.o stdio/fsetpos.o ctype/isprint.o stdlib/system.o stdio/tmpnam.o unistd/msleep.o stdlib/atof.o stdlib/strtod.o stdio/rename.o sys/stat/mkdir.o unistd/uptime.o
+#OBJ=crt0.o libc.o malloc/malloc.o pty.o sys/mman/mmap.o memset.o assert.o stdio/snprintf.o stdio/vfprintf.o string/memcpy.o string/memcmp.o string/strcmp.o ubsan.o string/strcpy.o isspace.o stdio/puts.o stdio/putchar.o dirent/opendir.o dirent/readdir.o dirent/closedir.o unistd/getopt.o dirent/scandir.o dirent/alphasort.o stdio/printf.o stdio/vdprintf.o stdio/vprintf.o stdio/dprintf.o stdio/vprintf.o string/strlen.o string/strnlen.o stdio/stdin.o stdio/stdout.o stdio/stderr.o stdio/getchar.o stdio/fgetc.o arpa/inet/htons.o arpa/inet/htonl.o stdio/fread.o stdio/fwrite.o stdio/fopen.o stdio/fclose.o stdio/fseek.o ctype/isascii.o stdio/fprintf.o stdlib/atoi.o stdlib/strtol.o ctype/toupper.o ctype/tolower.o string/strcat.o string/strchr.o string/sscanf.o sys/stat/stat.o stdlib/getenv.o string/strrchr.o stdio/ftell.o stdio/tmpfile.o stdio/fgets.o stdio/feof.o stdio/fscanf.o stdio/ungetc.o string/strncmp.o stdio/fputc.o string/strncpy.o stdio/remove.o stdio/ferror.o stdio/fputs.o stdlib/rand.o stdlib/srand.o unistd/getpid.o stdlib/strtoul.o stdio/fflush.o stdlib/abort.o string/strcspn.o time/localtime.o time/time.o time/clock_gettime.o time/gmtime.o time/strftime.o string/strpbrk.o ctype/isdigit.o ctype/isalpha.o ctype/isxdigit.o ctype/ispunct.o stdio/setvbuf.o stdio/fileno.o stdio/putc.o stdio/sprintf.o stdlib/abs.o string/strspn.o stdlib/qsort.o string/memmove.o setjmp/longjmp.o setjmp/setjmp.o
+all: libc.a
+
+%.o: %.c
+	$(CC) $(CFLAGS) -O0 -I. -o $@ -c $< -lgcc
+
+%.o: %.s
+	$(AS) $< -o $@
+
+libc.a: $(OBJ)
+	$(AR) rcs libc.a $(OBJ)
+
+install:
+	cp crt0.o /home/anton/prj/osdev/sysroot/lib/
+	cp libc.a /home/anton/prj/osdev/sysroot/lib/
+	cp -r include /home/anton/prj/osdev/sysroot/usr/
+
+clean:
+	rm libc.a *.o */*.o */*/*.o
diff --git a/userland/libc/arpa/inet.h b/userland/libc/arpa/inet.h
new file mode 100644
index 0000000..7a033f2
--- /dev/null
+++ b/userland/libc/arpa/inet.h
@@ -0,0 +1,4 @@
+#include <stdint.h>
+
+uint32_t htonl(uint32_t hostlong);
+uint16_t htons(uint16_t hostlong);
diff --git a/userland/libc/arpa/inet/htonl.c b/userland/libc/arpa/inet/htonl.c
new file mode 100644
index 0000000..4b66747
--- /dev/null
+++ b/userland/libc/arpa/inet/htonl.c
@@ -0,0 +1,11 @@
+#include <arpa/inet.h>
+#include <endian.h>
+#include <stdint.h>
+
+uint32_t htonl(uint32_t hostlong) {
+#if BYTE_ORDER == LITTLE_ENDIAN
+  hostlong = (uint32_t)(htons(hostlong >> 16)) |
+             (uint32_t)(htons(hostlong & 0xFFFF) << 16);
+#endif
+  return hostlong;
+}
diff --git a/userland/libc/arpa/inet/htons.c b/userland/libc/arpa/inet/htons.c
new file mode 100644
index 0000000..798a64a
--- /dev/null
+++ b/userland/libc/arpa/inet/htons.c
@@ -0,0 +1,10 @@
+#include <arpa/inet.h>
+#include <endian.h>
+#include <stdint.h>
+
+uint16_t htons(uint16_t hostlong) {
+#if BYTE_ORDER == LITTLE_ENDIAN
+  hostlong = ((hostlong & 0xFF00) >> 8) | ((hostlong & 0x00FF) << 8);
+#endif
+  return hostlong;
+}
diff --git a/userland/libc/assert.c b/userland/libc/assert.c
new file mode 100644
index 0000000..4082f64
--- /dev/null
+++ b/userland/libc/assert.c
@@ -0,0 +1,9 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void aFailed(char *f, int l) {
+  printf("Assert failed\n");
+  printf("%s : %d\n", f, l);
+  exit(1);
+}
diff --git a/userland/libc/assert.h b/userland/libc/assert.h
new file mode 100644
index 0000000..a009e5f
--- /dev/null
+++ b/userland/libc/assert.h
@@ -0,0 +1,10 @@
+#ifndef ASSERT_H
+#define ASSERT_H
+
+#define assert(expr)                                                            \
+  {                                                                            \
+    if (!(expr))                                                               \
+      aFailed(__FILE__, __LINE__);                                              \
+  }
+void aFailed(char *f, int l);
+#endif
diff --git a/userland/libc/crt0.s b/userland/libc/crt0.s
new file mode 100644
index 0000000..05144d4
--- /dev/null
+++ b/userland/libc/crt0.s
@@ -0,0 +1,13 @@
+.global _start
+.extern main
+_start:
+	call main
+	mov %eax, %ebx
+	mov $8, %eax
+	int $0x80
+l:
+	nop
+	nop
+	nop
+	nop
+	jmp l
diff --git a/userland/libc/ctype.h b/userland/libc/ctype.h
new file mode 100644
index 0000000..5be4a89
--- /dev/null
+++ b/userland/libc/ctype.h
@@ -0,0 +1,12 @@
+#ifndef CTYPE_H
+#define CTYPE_H
+
+int isspace(int c);
+int isascii(int c);
+int toupper(int c);
+int tolower(int c);
+int isdigit(int c);
+int isalpha(int c);
+int isxdigit(int c);
+int ispunct(int c);
+#endif
diff --git a/userland/libc/ctype/isalnum.c b/userland/libc/ctype/isalnum.c
new file mode 100644
index 0000000..870728d
--- /dev/null
+++ b/userland/libc/ctype/isalnum.c
@@ -0,0 +1,6 @@
+#include <ctype.h>
+
+// This is probably the most useless libc function I have seen so far.
+int isalnum(int c) {
+	return isalpha(c) || isdigit(c);
+}
diff --git a/userland/libc/ctype/isalpha.c b/userland/libc/ctype/isalpha.c
new file mode 100644
index 0000000..130f493
--- /dev/null
+++ b/userland/libc/ctype/isalpha.c
@@ -0,0 +1,4 @@
+#include <ctype.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/isalpha.html
+int isalpha(int c) { return (('A' <= toupper(c)) && ('Z' >= toupper(c))); }
diff --git a/userland/libc/ctype/isascii.c b/userland/libc/ctype/isascii.c
new file mode 100644
index 0000000..660c8bb
--- /dev/null
+++ b/userland/libc/ctype/isascii.c
@@ -0,0 +1,4 @@
+#include <ctype.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/isascii.html
+int isascii(int c) { return (c < 128); }
diff --git a/userland/libc/ctype/isdigit.c b/userland/libc/ctype/isdigit.c
new file mode 100644
index 0000000..790b9f1
--- /dev/null
+++ b/userland/libc/ctype/isdigit.c
@@ -0,0 +1,6 @@
+#include <ctype.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/isdigit.html
+int isdigit(int c) {
+  return ('0' <= c && c <= '9');
+}
diff --git a/userland/libc/ctype/isprint.c b/userland/libc/ctype/isprint.c
new file mode 100644
index 0000000..e6a3d0e
--- /dev/null
+++ b/userland/libc/ctype/isprint.c
@@ -0,0 +1,3 @@
+#include <ctype.h>
+
+int isprint(int c) { return c > 0x20 && 0x7F != c; }
diff --git a/userland/libc/ctype/ispunct.c b/userland/libc/ctype/ispunct.c
new file mode 100644
index 0000000..18dc7d8
--- /dev/null
+++ b/userland/libc/ctype/ispunct.c
@@ -0,0 +1,6 @@
+#include <ctype.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/ispunct.html
+int ispunct(int c) {
+	return (c == '.');
+}
diff --git a/userland/libc/ctype/isxdigit.c b/userland/libc/ctype/isxdigit.c
new file mode 100644
index 0000000..c843725
--- /dev/null
+++ b/userland/libc/ctype/isxdigit.c
@@ -0,0 +1,6 @@
+#include <ctype.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/isxdigit.html
+int isxdigit(int c) {
+  return isdigit(c) || ('A' >= toupper(c) && 'Z' <= toupper(c));
+}
diff --git a/userland/libc/ctype/tolower.c b/userland/libc/ctype/tolower.c
new file mode 100644
index 0000000..f1bb163
--- /dev/null
+++ b/userland/libc/ctype/tolower.c
@@ -0,0 +1,7 @@
+#include <ctype.h>
+
+int tolower(int c) {
+  if (c >= 'A' && c <= 'Z')
+    return c - 'A' + 'a';
+  return c;
+}
diff --git a/userland/libc/ctype/toupper.c b/userland/libc/ctype/toupper.c
new file mode 100644
index 0000000..0f33886
--- /dev/null
+++ b/userland/libc/ctype/toupper.c
@@ -0,0 +1,7 @@
+#include <ctype.h>
+
+int toupper(int c) {
+  if (c >= 'a' && c <= 'z')
+    return c - 'a' + 'A';
+  return c;
+}
diff --git a/userland/libc/dirent.h b/userland/libc/dirent.h
new file mode 100644
index 0000000..f190a7c
--- /dev/null
+++ b/userland/libc/dirent.h
@@ -0,0 +1,28 @@
+#ifndef DIRENT_H
+#define DIRENT_H
+#include <fcntl.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+struct dirent {
+  ino_t d_ino;           // File serial number.
+  char d_name[PATH_MAX]; // Filename string of entry.
+};
+
+typedef struct {
+  int fd;
+  struct dirent internal_direntry;
+  int dir_num;
+} DIR;
+
+DIR *opendir(const char *dirname);
+struct dirent *readdir(DIR *dir);
+int closedir(DIR *dirp);
+int alphasort(const struct dirent **d1, const struct dirent **d2);
+int scandir(const char *dir, struct dirent ***namelist,
+            int (*sel)(const struct dirent *),
+            int (*compar)(const struct dirent **, const struct dirent **));
+#endif
diff --git a/userland/libc/dirent/alphasort.c b/userland/libc/dirent/alphasort.c
new file mode 100644
index 0000000..43a4b5f
--- /dev/null
+++ b/userland/libc/dirent/alphasort.c
@@ -0,0 +1,7 @@
+#include <dirent.h>
+
+int alphasort(const struct dirent **d1, const struct dirent **d2) {
+  // TODO: Actually sort it
+  *d2 = *d1;
+  return 0;
+}
diff --git a/userland/libc/dirent/closedir.c b/userland/libc/dirent/closedir.c
new file mode 100644
index 0000000..e216d7c
--- /dev/null
+++ b/userland/libc/dirent/closedir.c
@@ -0,0 +1,7 @@
+#include <dirent.h>
+
+int closedir(DIR *dir) {
+  close(dir->fd);
+  free(dir);
+  return 0;
+}
diff --git a/userland/libc/dirent/opendir.c b/userland/libc/dirent/opendir.c
new file mode 100644
index 0000000..7bfa562
--- /dev/null
+++ b/userland/libc/dirent/opendir.c
@@ -0,0 +1,11 @@
+#include <dirent.h>
+
+DIR *opendir(const char *dirname) {
+  int fd = open(dirname, O_RDONLY, 0);
+  if (-1 == fd)
+    return NULL;
+  DIR *rc = malloc(sizeof(DIR));
+  rc->fd = fd;
+  rc->dir_num = 0;
+  return rc;
+}
diff --git a/userland/libc/dirent/readdir.c b/userland/libc/dirent/readdir.c
new file mode 100644
index 0000000..88aff48
--- /dev/null
+++ b/userland/libc/dirent/readdir.c
@@ -0,0 +1,14 @@
+#include <dirent.h>
+
+struct dirent *readdir(DIR *dir) {
+  size_t offset = dir->dir_num * sizeof(struct dirent);
+  int rc;
+  if (-1 == (rc = pread(dir->fd, &dir->internal_direntry, sizeof(struct dirent),
+                        offset)))
+    return NULL;
+  if (rc < sizeof(struct dirent))
+    return NULL;
+
+  dir->dir_num++;
+  return &(dir->internal_direntry);
+}
diff --git a/userland/libc/dirent/scandir.c b/userland/libc/dirent/scandir.c
new file mode 100644
index 0000000..1520140
--- /dev/null
+++ b/userland/libc/dirent/scandir.c
@@ -0,0 +1,43 @@
+#include <dirent.h>
+#include <stdlib.h>
+#include <string.h>
+
+int nop_sel(const struct dirent *unused) {
+  (void)unused;
+  return 1;
+}
+
+int nop_compar(const struct dirent **d1, const struct dirent **d2) {
+  *d2 = *d1;
+  return 0;
+}
+
+int scandir(const char *dir, struct dirent ***namelist,
+            int (*sel)(const struct dirent *),
+            int (*compar)(const struct dirent **, const struct dirent **)) {
+  if (!sel)
+    sel = nop_sel;
+
+  if (!compar)
+    compar = nop_compar;
+
+  DIR *d = opendir(dir);
+  struct dirent **list = NULL;
+  struct dirent *e;
+  int rc = 0;
+  for (; (e = readdir(d));) {
+    if (!sel(e))
+      continue;
+    struct dirent *p = malloc(sizeof(struct dirent));
+    memcpy(p, e, sizeof(struct dirent));
+    list = realloc(list, (rc + 1) * sizeof(struct dirent *));
+    list[rc] = p;
+    rc++;
+  }
+  //  struct dirent **new_list;
+  //  compar((const struct dirent **)list, (const struct dirent **)new_list);
+  //  *namelist = new_list;
+  *namelist = list;
+  // closedir(d);
+  return rc;
+}
diff --git a/userland/libc/endian.h b/userland/libc/endian.h
new file mode 100644
index 0000000..f265a67
--- /dev/null
+++ b/userland/libc/endian.h
@@ -0,0 +1,2 @@
+#define LITTLE_ENDIAN 0
+#define BYTE_ORDER LITTLE_ENDIAN
diff --git a/userland/libc/errno.h b/userland/libc/errno.h
new file mode 100644
index 0000000..ec9a25e
--- /dev/null
+++ b/userland/libc/errno.h
@@ -0,0 +1,87 @@
+#ifndef ERRNO_H
+#define ERRNO_H
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+#define E2BIG 1         // Argument list too long.
+#define EACCES 2        // Permission denied.
+#define EADDRINUSE 3    // Address in use.
+#define EADDRNOTAVAIL 4 // Address not available.
+#define EAFNOSUPPORT 5  // Address family not supported.
+#define EAGAIN 6        // Resource unavailable, try again.
+#define EALREADY 7      // Connection already in progress.
+#define EBADF 8         // Bad file descriptor.
+#define EBADMSG 9       // Bad message.
+#define EBUSY 10        // Device or resource busy.
+#define ECANCELED 11    // Operation canceled.
+#define ECHILD 12       // No child processes.
+#define ECONNABORTED 13 // Connection aborted.
+#define ECONNREFUSED 14 // Connection refused.
+#define ECONNRESET 15   // Connection reset.
+#define EDEADLK 16      // Resource deadlock would occur.
+#define EDESTADDRREQ 17 // Destination address required.
+#define EDOM 18         // Mathematics argument out of domain of function.
+#define EDQUOT 19       // Reserved.
+#define EEXIST 20       // File exists.
+#define EFAULT 21       // Bad address.
+#define EFBIG 22        // File too large.
+#define EHOSTUNREACH 23 // Host is unreachable.
+#define EIDRM 24        // Identifier removed.
+#define EILSEQ 25       // Illegal byte sequence.
+#define EINPROGRESS 26  // Operation in progress.
+#define EINTR 27        // Interrupted function.
+#define EINVAL 28       // Invalid argument.
+#define EIO 29          // I/O error.
+#define EISCONN 30      // Socket is connected.
+#define EISDIR 31       // Is a directory.
+#define ELOOP 32        // Too many levels of symbolic links.
+#define EMFILE 33       // File descriptor value too large.
+#define EMLINK 34       // Too many links.
+#define EMSGSIZE 35     // Message too large.
+#define EMULTIHOP 36    // Reserved.
+#define ENAMETOOLONG 37 // Filename too long.
+#define ENETDOWN 38     // Network is down.
+#define ENETRESET 39    // Connection aborted by network.
+#define ENETUNREACH 40  // Network unreachable.
+#define ENFILE 41       // Too many files open in system.
+#define ENOBUFS 42      // No buffer space available.
+#define ENODATA 43     // No message is available on the STREAM head read queue.
+#define ENODEV 44      // No such device.
+#define ENOENT 45      // No such file or directory.
+#define ENOEXEC 46     // Executable file format error.
+#define ENOLCK 47      // No locks available.
+#define ENOLINK 48     // Reserved.
+#define ENOMEM 49      // Not enough space.
+#define ENOMSG 50      // No message of the desired type.
+#define ENOPROTOOPT 51 // Protocol not available.
+#define ENOSPC 52      // No space left on device.
+#define ENOSR 53       // No STREAM resources.
+#define ENOSTR 54      // Not a STREAM.
+#define ENOSYS 55      // Functionality not supported.
+#define ENOTCONN 56    // The socket is not connected.
+#define ENOTDIR 57     // Not a directory or a symbolic link to a directory.
+#define ENOTEMPTY 58   // Directory not empty.
+#define ENOTRECOVERABLE 59 // State not recoverable.
+#define ENOTSOCK 60        // Not a socket.
+#define ENOTSUP 61         // Not supported (may be the same value as.
+#define ENOTTY 62          // Inappropriate I/O control operation.
+#define ENXIO 63           // No such device or address.
+#define EOPNOTSUPP ENOTSUP // Operation not supported on socket.
+#define EOVERFLOW 65       // Value too large to be stored in data type.
+#define EOWNERDEAD 66      // Previous owner died.
+#define EPERM 67           // Operation not permitted.
+#define EPIPE 68           // Broken pipe.
+#define EPROTO 69          // Protocol error.
+#define EPROTONOSUPPORT 70 // Protocol not supported.
+#define EPROTOTYPE 71      // Protocol wrong type for socket.
+#define ERANGE 72          // Result too large.
+#define EROFS 73           // Read-only file system.
+#define ESPIPE 74          // Invalid seek.
+#define ESRCH 75           // No such process.
+#define ESTALE 76          // Reserved.
+#define ETIME 77           // Stream ioctl() timeout.
+#define ETIMEDOUT 78       // Connection timed out.
+#define ETXTBSY 79         // Text file busy.
+#define EWOULDBLOCK EAGAIN // Operation would block.
+#define EXDEV 81           // Cross-device link.
+
+extern int errno;
+#endif
diff --git a/userland/libc/fcntl.h b/userland/libc/fcntl.h
new file mode 100644
index 0000000..4c1eb9c
--- /dev/null
+++ b/userland/libc/fcntl.h
@@ -0,0 +1,10 @@
+// FIXME: Is there some standard value for this?
+#define O_NONBLOCK (1 << 0)
+#define O_READ (1 << 1)
+#define O_WRITE (1 << 2)
+#define O_CREAT (1 << 3)
+#define O_RDONLY O_READ
+#define O_WRONLY O_WRITE
+#define O_RDWR (O_WRITE | O_READ)
+
+int open(const char *file, int flags, int mode);
diff --git a/userland/libc/include/arpa/inet.h b/userland/libc/include/arpa/inet.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/arpa/inet.h
diff --git a/userland/libc/include/assert.h b/userland/libc/include/assert.h
new file mode 100644
index 0000000..a009e5f
--- /dev/null
+++ b/userland/libc/include/assert.h
@@ -0,0 +1,10 @@
+#ifndef ASSERT_H
+#define ASSERT_H
+
+#define assert(expr)                                                            \
+  {                                                                            \
+    if (!(expr))                                                               \
+      aFailed(__FILE__, __LINE__);                                              \
+  }
+void aFailed(char *f, int l);
+#endif
diff --git a/userland/libc/include/byteswap.h b/userland/libc/include/byteswap.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/byteswap.h
diff --git a/userland/libc/include/ctype.h b/userland/libc/include/ctype.h
new file mode 100644
index 0000000..7c8c311
--- /dev/null
+++ b/userland/libc/include/ctype.h
@@ -0,0 +1,14 @@
+#ifndef CTYPE_H
+#define CTYPE_H
+
+int isspace(int c);
+int isascii(int c);
+int toupper(int c);
+int tolower(int c);
+int isdigit(int c);
+int isalpha(int c);
+int isxdigit(int c);
+int ispunct(int c);
+int isalnum(int c);
+int isprint(int c);
+#endif
diff --git a/userland/libc/include/dirent.h b/userland/libc/include/dirent.h
new file mode 100644
index 0000000..f190a7c
--- /dev/null
+++ b/userland/libc/include/dirent.h
@@ -0,0 +1,28 @@
+#ifndef DIRENT_H
+#define DIRENT_H
+#include <fcntl.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+struct dirent {
+  ino_t d_ino;           // File serial number.
+  char d_name[PATH_MAX]; // Filename string of entry.
+};
+
+typedef struct {
+  int fd;
+  struct dirent internal_direntry;
+  int dir_num;
+} DIR;
+
+DIR *opendir(const char *dirname);
+struct dirent *readdir(DIR *dir);
+int closedir(DIR *dirp);
+int alphasort(const struct dirent **d1, const struct dirent **d2);
+int scandir(const char *dir, struct dirent ***namelist,
+            int (*sel)(const struct dirent *),
+            int (*compar)(const struct dirent **, const struct dirent **));
+#endif
diff --git a/userland/libc/include/endian.h b/userland/libc/include/endian.h
new file mode 100644
index 0000000..f265a67
--- /dev/null
+++ b/userland/libc/include/endian.h
@@ -0,0 +1,2 @@
+#define LITTLE_ENDIAN 0
+#define BYTE_ORDER LITTLE_ENDIAN
diff --git a/userland/libc/include/err.h b/userland/libc/include/err.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/err.h
diff --git a/userland/libc/include/errno.h b/userland/libc/include/errno.h
new file mode 100644
index 0000000..ec9a25e
--- /dev/null
+++ b/userland/libc/include/errno.h
@@ -0,0 +1,87 @@
+#ifndef ERRNO_H
+#define ERRNO_H
+// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+#define E2BIG 1         // Argument list too long.
+#define EACCES 2        // Permission denied.
+#define EADDRINUSE 3    // Address in use.
+#define EADDRNOTAVAIL 4 // Address not available.
+#define EAFNOSUPPORT 5  // Address family not supported.
+#define EAGAIN 6        // Resource unavailable, try again.
+#define EALREADY 7      // Connection already in progress.
+#define EBADF 8         // Bad file descriptor.
+#define EBADMSG 9       // Bad message.
+#define EBUSY 10        // Device or resource busy.
+#define ECANCELED 11    // Operation canceled.
+#define ECHILD 12       // No child processes.
+#define ECONNABORTED 13 // Connection aborted.
+#define ECONNREFUSED 14 // Connection refused.
+#define ECONNRESET 15   // Connection reset.
+#define EDEADLK 16      // Resource deadlock would occur.
+#define EDESTADDRREQ 17 // Destination address required.
+#define EDOM 18         // Mathematics argument out of domain of function.
+#define EDQUOT 19       // Reserved.
+#define EEXIST 20       // File exists.
+#define EFAULT 21       // Bad address.
+#define EFBIG 22        // File too large.
+#define EHOSTUNREACH 23 // Host is unreachable.
+#define EIDRM 24        // Identifier removed.
+#define EILSEQ 25       // Illegal byte sequence.
+#define EINPROGRESS 26  // Operation in progress.
+#define EINTR 27        // Interrupted function.
+#define EINVAL 28       // Invalid argument.
+#define EIO 29          // I/O error.
+#define EISCONN 30      // Socket is connected.
+#define EISDIR 31       // Is a directory.
+#define ELOOP 32        // Too many levels of symbolic links.
+#define EMFILE 33       // File descriptor value too large.
+#define EMLINK 34       // Too many links.
+#define EMSGSIZE 35     // Message too large.
+#define EMULTIHOP 36    // Reserved.
+#define ENAMETOOLONG 37 // Filename too long.
+#define ENETDOWN 38     // Network is down.
+#define ENETRESET 39    // Connection aborted by network.
+#define ENETUNREACH 40  // Network unreachable.
+#define ENFILE 41       // Too many files open in system.
+#define ENOBUFS 42      // No buffer space available.
+#define ENODATA 43     // No message is available on the STREAM head read queue.
+#define ENODEV 44      // No such device.
+#define ENOENT 45      // No such file or directory.
+#define ENOEXEC 46     // Executable file format error.
+#define ENOLCK 47      // No locks available.
+#define ENOLINK 48     // Reserved.
+#define ENOMEM 49      // Not enough space.
+#define ENOMSG 50      // No message of the desired type.
+#define ENOPROTOOPT 51 // Protocol not available.
+#define ENOSPC 52      // No space left on device.
+#define ENOSR 53       // No STREAM resources.
+#define ENOSTR 54      // Not a STREAM.
+#define ENOSYS 55      // Functionality not supported.
+#define ENOTCONN 56    // The socket is not connected.
+#define ENOTDIR 57     // Not a directory or a symbolic link to a directory.
+#define ENOTEMPTY 58   // Directory not empty.
+#define ENOTRECOVERABLE 59 // State not recoverable.
+#define ENOTSOCK 60        // Not a socket.
+#define ENOTSUP 61         // Not supported (may be the same value as.
+#define ENOTTY 62          // Inappropriate I/O control operation.
+#define ENXIO 63           // No such device or address.
+#define EOPNOTSUPP ENOTSUP // Operation not supported on socket.
+#define EOVERFLOW 65       // Value too large to be stored in data type.
+#define EOWNERDEAD 66      // Previous owner died.
+#define EPERM 67           // Operation not permitted.
+#define EPIPE 68           // Broken pipe.
+#define EPROTO 69          // Protocol error.
+#define EPROTONOSUPPORT 70 // Protocol not supported.
+#define EPROTOTYPE 71      // Protocol wrong type for socket.
+#define ERANGE 72          // Result too large.
+#define EROFS 73           // Read-only file system.
+#define ESPIPE 74          // Invalid seek.
+#define ESRCH 75           // No such process.
+#define ESTALE 76          // Reserved.
+#define ETIME 77           // Stream ioctl() timeout.
+#define ETIMEDOUT 78       // Connection timed out.
+#define ETXTBSY 79         // Text file busy.
+#define EWOULDBLOCK EAGAIN // Operation would block.
+#define EXDEV 81           // Cross-device link.
+
+extern int errno;
+#endif
diff --git a/userland/libc/include/fcntl.h b/userland/libc/include/fcntl.h
new file mode 100644
index 0000000..7f0906d
--- /dev/null
+++ b/userland/libc/include/fcntl.h
@@ -0,0 +1,12 @@
+// FIXME: Is there some standard value for this?
+#define O_NONBLOCK (1 << 0)
+#define O_READ (1 << 1)
+#define O_WRITE (1 << 2)
+#define O_CREAT (1 << 3)
+#define O_TRUNC (1 << 4)
+
+#define O_RDONLY O_READ
+#define O_WRONLY O_WRITE
+#define O_RDWR (O_WRITE | O_READ)
+
+int open(const char *file, int flags, int mode);
diff --git a/userland/libc/include/fnmatch.h b/userland/libc/include/fnmatch.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/fnmatch.h
diff --git a/userland/libc/include/glob.h b/userland/libc/include/glob.h
new file mode 100644
index 0000000..f9e9c57
--- /dev/null
+++ b/userland/libc/include/glob.h
@@ -0,0 +1,10 @@
+#ifndef GLOB_H
+#define GLOB_H
+#include <stddef.h>
+
+typedef struct {
+  size_t gl_pathc; // Count of paths matched by pattern.
+  char **gl_pathv; // Pointer to a list of matched pathnames
+  size_t gl_offs;  // Slots to reserve at the beginning of gl_pathv.
+} glob_t;
+#endif
diff --git a/userland/libc/include/grp.h b/userland/libc/include/grp.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/grp.h
diff --git a/userland/libc/include/input.h b/userland/libc/include/input.h
new file mode 100644
index 0000000..a6602f5
--- /dev/null
+++ b/userland/libc/include/input.h
@@ -0,0 +1,9 @@
+#ifndef INPUT_H
+#define INPUT_H
+#include <stdint.h>
+
+struct input_event {
+  uint16_t key;
+  uint8_t status;
+};
+#endif
diff --git a/userland/libc/include/inttypes.h b/userland/libc/include/inttypes.h
new file mode 100644
index 0000000..adde7c8
--- /dev/null
+++ b/userland/libc/include/inttypes.h
@@ -0,0 +1,19 @@
+#include <stdint.h>
+
+// FIXME: These are not correct
+#define PRId8 "d"
+#define PRId16 "d"
+#define PRId32 "d"
+#define PRId64 "d"
+#define PRIu8 "d"
+#define PRIu16 "d"
+#define PRIu32 "d"
+#define PRIu64 "d"
+#define PRIx8 "x"
+#define PRIx16 "x"
+#define PRIx32 "x"
+#define PRIx64 "x"
+#define PRIX8 "x"
+#define PRIX16 "x"
+#define PRIX32 "x"
+#define PRIX64 "x"
diff --git a/userland/libc/include/langinfo.h b/userland/libc/include/langinfo.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/langinfo.h
diff --git a/userland/libc/include/libgen.h b/userland/libc/include/libgen.h
new file mode 100644
index 0000000..16dc3ed
--- /dev/null
+++ b/userland/libc/include/libgen.h
@@ -0,0 +1,6 @@
+#ifndef LIBGEN_H
+#define LIBGEN_H
+
+char *basename(char *path);
+char *dirname(char *path);
+#endif
diff --git a/userland/libc/include/limits.h b/userland/libc/include/limits.h
new file mode 100644
index 0000000..6d0abe0
--- /dev/null
+++ b/userland/libc/include/limits.h
@@ -0,0 +1,4 @@
+#define PATH_MAX 256
+#define FILENAME_MAX PATH_MAX
+#define ULONG_MAX 0xFFFFFFFFUL
+#define LONG_MAX 2147483647
diff --git a/userland/libc/include/locale.h b/userland/libc/include/locale.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/locale.h
diff --git a/userland/libc/include/math.h b/userland/libc/include/math.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/math.h
diff --git a/userland/libc/include/net/if.h b/userland/libc/include/net/if.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/net/if.h
diff --git a/userland/libc/include/netdb.h b/userland/libc/include/netdb.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/netdb.h
diff --git a/userland/libc/include/netinet/in.h b/userland/libc/include/netinet/in.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/netinet/in.h
diff --git a/userland/libc/include/netinet/tcp.h b/userland/libc/include/netinet/tcp.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/netinet/tcp.h
diff --git a/userland/libc/include/paths.h b/userland/libc/include/paths.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/paths.h
diff --git a/userland/libc/include/poll.h b/userland/libc/include/poll.h
new file mode 100644
index 0000000..e3c6d8d
--- /dev/null
+++ b/userland/libc/include/poll.h
@@ -0,0 +1,17 @@
+#ifndef POLL_H
+#define POLL_H
+#include <stddef.h>
+
+#define POLLIN (1 << 0)
+#define POLLPRI (1 << 1)
+#define POLLOUT (1 << 2)
+#define POLLHUP (1 << 3)
+
+struct pollfd {
+  int fd;
+  short events;
+  short revents;
+};
+
+int poll(struct pollfd *fds, size_t nfds, int timeout);
+#endif
diff --git a/userland/libc/include/pty.h b/userland/libc/include/pty.h
new file mode 100644
index 0000000..b8ce978
--- /dev/null
+++ b/userland/libc/include/pty.h
@@ -0,0 +1,6 @@
+#ifndef PTY_H
+#define PTY_H
+int openpty(int *amaster, int *aslave, char *name,
+                    /*const struct termios*/ void *termp,
+                    /*const struct winsize*/ void *winp);
+#endif
diff --git a/userland/libc/include/pwd.h b/userland/libc/include/pwd.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/pwd.h
diff --git a/userland/libc/include/regex.h b/userland/libc/include/regex.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/regex.h
diff --git a/userland/libc/include/sched.h b/userland/libc/include/sched.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sched.h
diff --git a/userland/libc/include/setjmp.h b/userland/libc/include/setjmp.h
new file mode 100644
index 0000000..ea15cf3
--- /dev/null
+++ b/userland/libc/include/setjmp.h
@@ -0,0 +1,14 @@
+#ifndef SETJMP_H
+#define SETJMP_H
+typedef unsigned long __jmp_buf[6];
+typedef struct __jmp_buf_tag {
+	__jmp_buf __jb;
+	unsigned long __fl;
+	unsigned long __ss[128/sizeof(long)];
+} jmp_buf[1];
+typedef jmp_buf sigjmp_buf;
+
+void _longjmp(jmp_buf, int);
+void longjmp(jmp_buf, int);
+void siglongjmp(sigjmp_buf, int);
+#endif
diff --git a/userland/libc/include/signal.h b/userland/libc/include/signal.h
new file mode 100644
index 0000000..2e6566d
--- /dev/null
+++ b/userland/libc/include/signal.h
@@ -0,0 +1,9 @@
+#ifndef SIGNAL_H
+#define SIGNAL_H
+#define SIGHUP 0
+#define SIGINT 1
+#define SIGWINCH 2
+#define SIGQUIT 3
+#define SIG_IGN 4
+typedef int sig_atomic_t;
+#endif // SIGNAL_H
diff --git a/userland/libc/include/socket.h b/userland/libc/include/socket.h
new file mode 100644
index 0000000..5e86b45
--- /dev/null
+++ b/userland/libc/include/socket.h
@@ -0,0 +1,41 @@
+#include <stddef.h>
+#include <stdint.h>
+
+#define AF_UNIX 0
+#define AF_LOCAL AF_UNIX
+
+#define INADDR_ANY 0
+
+typedef struct {
+  int domain;
+  int type;
+  int protocol;
+
+  // UNIX socket
+  char *path;
+  int incoming_fd;
+} SOCKET;
+
+typedef struct {
+  char *path;
+  SOCKET *s;
+} OPEN_UNIX_SOCKET;
+
+typedef uint32_t in_addr_t;
+typedef uint16_t in_port_t;
+typedef unsigned int sa_family_t;
+typedef uint32_t socklen_t;
+
+struct sockaddr {
+  sa_family_t sa_family; /* Address family */
+  char *sa_data;         /* Socket address */
+};
+
+struct sockaddr_un {
+  sa_family_t sun_family; /* Address family */
+  char *sun_path;         /* Socket pathname */
+};
+
+int socket(int domain, int type, int protocol);
+int accept(int socket, struct sockaddr *address, socklen_t *address_len);
+int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
diff --git a/userland/libc/include/stdio.h b/userland/libc/include/stdio.h
new file mode 100644
index 0000000..014e2ac
--- /dev/null
+++ b/userland/libc/include/stdio.h
@@ -0,0 +1,116 @@
+#ifndef STDIO_H
+#define STDIO_H
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
+
+// FIXME: Most of these should probably not be here. But I am too lazy
+// to fix it right now. This is futures mees problem to deal wth.
+
+#define EOF (-1)
+
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+
+#define BUFSIZ 4096
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/setvbuf.html
+#define _IOFBF 1 // shall cause input/output to be fully buffered.
+#define _IOLBF 2 // shall cause input/output to be line buffered.
+#define _IONBF 3 // shall cause input/output to be unbuffered.
+
+typedef long fpos_t;
+
+typedef struct __IO_FILE FILE;
+struct __IO_FILE {
+  size_t (*write)(FILE *, const unsigned char *, size_t);
+  size_t (*read)(FILE *, unsigned char *, size_t);
+  int (*seek)(FILE *, long, int);
+  long offset_in_file;
+  int buffered_char;
+  int has_buffered_char;
+  int fd;
+  uint8_t is_eof;
+  uint8_t has_error;
+  uint64_t file_size;
+  void *cookie;
+};
+
+size_t write_fd(FILE *f, const unsigned char *s, size_t l);
+size_t read_fd(FILE *f, unsigned char *s, size_t l);
+int seek_fd(FILE *stream, long offset, int whence);
+
+typedef struct {
+  int fd;
+} FILE_FD_COOKIE;
+
+extern FILE __stdin_FILE;
+extern FILE __stdout_FILE;
+extern FILE __stderr_FILE;
+
+#define stdin (&__stdin_FILE)
+#define stdout (&__stdout_FILE)
+//#define stderr (&__stderr_FILE)
+#define stderr (&__stdout_FILE)
+
+typedef int mode_t;
+
+void perror(const char *s);
+
+int putchar(int c);
+int puts(const char *s);
+int brk(void *addr);
+void *sbrk(intptr_t increment);
+int write(int fd, const char *buf, size_t count);
+int pwrite(int fd, const char *buf, size_t count, size_t offset);
+int printf(const char *format, ...);
+int pread(int fd, void *buf, size_t count, size_t offset);
+int read(int fd, void *buf, size_t count);
+int fork(void);
+int memcmp(const void *s1, const void *s2, size_t n);
+int wait(int *stat_loc);
+void exit(int status);
+void *memcpy(void *dest, const void *src, uint32_t n);
+int shm_open(const char *name, int oflag, mode_t mode);
+int dprintf(int fd, const char *format, ...);
+int vdprintf(int fd, const char *format, va_list ap);
+int vprintf(const char *format, va_list ap);
+int snprintf(char *str, size_t size, const char *format, ...);
+int vsnprintf(char *str, size_t size, const char *format, va_list ap);
+int vfprintf(FILE *f, const char *fmt, va_list ap);
+int fgetc(FILE *stream);
+int getchar(void);
+#define getc(_a) fgetc(_a)
+size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
+size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
+FILE *fopen(const char *pathname, const char *mode);
+int fclose(FILE *stream);
+int fseek(FILE *stream, long offset, int whence);
+int fprintf(FILE *f, const char *fmt, ...);
+int atoi(const char *str);
+long strtol(const char *nptr, char **endptr, int base);
+char *strchr(const char *s, int c);
+char *strcat(char *s1, const char *s2);
+char *fgets(char *s, int n, FILE *stream);
+FILE *tmpfile(void);
+int feof(FILE *stream);
+int fscanf(FILE *stream, const char *format, ...);
+int ungetc(int c, FILE *stream);
+long ftell(FILE *stream);
+int fputc(int c, FILE *stream);
+int remove(const char *path);
+int ferror(FILE *stream);
+int fputs(const char *s, FILE *stream);
+int fflush(FILE *stream);
+int setvbuf(FILE *stream, char *restrict buf, int type, size_t size);
+int fileno(FILE *stream);
+int putc(int c, FILE *stream);
+int vsprintf(char *str, const char *format, va_list ap);
+int sprintf(char *str, const char *format, ...);
+FILE *open_memstream(char **bufp, size_t *sizep);
+int fsetpos(FILE *stream, const fpos_t *pos);
+int fgetpos(FILE *restrict stream, fpos_t *restrict pos);
+char *tmpnam(char *s);
+int rename(const char *old, const char *new);
+#endif
diff --git a/userland/libc/include/stdlib.h b/userland/libc/include/stdlib.h
new file mode 100644
index 0000000..c88f2f3
--- /dev/null
+++ b/userland/libc/include/stdlib.h
@@ -0,0 +1,32 @@
+#ifndef STDLIB_H
+#define STDLIB_H
+#include <limits.h>
+#include <stddef.h>
+#define RAND_MAX (UINT32_MAX)
+#define EXIT_SUCCESS 0
+#define EXIT_FAILURE 1
+
+typedef size_t size_t; // only for 32 bit
+
+void *malloc(size_t s);
+void *calloc(size_t nelem, size_t elsize);
+void *realloc(void *ptr, size_t size);
+void free(void *p);
+char *getenv(const char *name);
+int rand(void);
+void srand(unsigned int seed);
+unsigned long strtoul(const char *restrict str, char **restrict endptr,
+                      int base);
+long strtol(const char *str, char **restrict endptr, int base);
+void abort(void);
+int abs(int i);
+void qsort(void *base, size_t nel, size_t width,
+           int (*compar)(const void *, const void *));
+int atexit(void (*func)(void));
+int mkstemp(char *template);
+long double strtold(const char *restrict nptr, char **restrict endptr);
+int system(const char *command);
+double atof(const char *str);
+double strtod(const char *restrict nptr, char **restrict endptr);
+int atoi(const char *str);
+#endif
diff --git a/userland/libc/include/string.h b/userland/libc/include/string.h
new file mode 100644
index 0000000..0c61efa
--- /dev/null
+++ b/userland/libc/include/string.h
@@ -0,0 +1,29 @@
+#ifndef STRING_H
+#define STRING_H
+#include <stddef.h>
+#include <stdint.h>
+
+char *strerror(int errnum);
+void *memset(void *s, int c, size_t n);
+void *memcpy(void *dest, const void *src, uint32_t n);
+int strcmp(const char *s1, const char *s2);
+char *strcpy(char *dest, const char *src);
+size_t strlen(const char *s);
+size_t strnlen(const char *s, size_t maxlen);
+int sscanf(const char *s, const char *restrict format, ...);
+char *strrchr(const char *s, int c);
+int strncmp(const char *s1, const char *s2, size_t n);
+char *strncpy(char *s1, const char *s2, size_t n);
+size_t *strlcpy(char *s1, const char *s2, size_t n);
+size_t strcspn(const char *s1, const char *s2);
+char *strpbrk(const char *s1, const char *s2);
+size_t strspn(const char *s1, const char *s2);
+void *memmove(void *s1, const void *s2, size_t n);
+char *strdup(const char *s);
+char *strndup(const char *s, size_t size);
+char *strstr(const char *s1, const char *s2);
+int strncasecmp(const char *s1, const char *s2, size_t n);
+int strcasecmp(const char *s1, const char *s2);
+char *strtok(char *restrict s, const char *restrict sep);
+char *strcat(char *restrict s1, const char *restrict s2);
+#endif
diff --git a/userland/libc/include/strings.h b/userland/libc/include/strings.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/strings.h
diff --git a/userland/libc/include/sys/ioctl.h b/userland/libc/include/sys/ioctl.h
new file mode 100644
index 0000000..a373a4b
--- /dev/null
+++ b/userland/libc/include/sys/ioctl.h
@@ -0,0 +1,10 @@
+#ifndef IOCTL_H
+#define IOCTL_H
+#define TIOCGWINSZ 0
+struct winsize {
+  unsigned short ws_row;
+  unsigned short ws_col;
+  unsigned short ws_xpixel;
+  unsigned short ws_ypixel;
+};
+#endif // IOCTL_H
diff --git a/userland/libc/include/sys/mman.h b/userland/libc/include/sys/mman.h
new file mode 100644
index 0000000..7dfe29a
--- /dev/null
+++ b/userland/libc/include/sys/mman.h
@@ -0,0 +1,15 @@
+#ifndef MMAP_H
+#define MMAP_H
+#include <stdint.h>
+#include <stddef.h>
+
+#define PROT_READ (1 << 0)
+#define PROT_WRITE (1 << 1)
+
+#define MAP_PRIVATE  (1 << 0)
+#define MAP_ANONYMOUS (1<< 1)
+#define MAP_SHARED (1<< 2)
+
+void *mmap(void *addr, size_t length, int prot, int flags, int fd,
+           size_t offset);
+#endif
diff --git a/userland/libc/include/sys/mount.h b/userland/libc/include/sys/mount.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/mount.h
diff --git a/userland/libc/include/sys/resource.h b/userland/libc/include/sys/resource.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/resource.h
diff --git a/userland/libc/include/sys/socket.h b/userland/libc/include/sys/socket.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/socket.h
diff --git a/userland/libc/include/sys/stat.h b/userland/libc/include/sys/stat.h
new file mode 100644
index 0000000..178d014
--- /dev/null
+++ b/userland/libc/include/sys/stat.h
@@ -0,0 +1,31 @@
+#ifndef STAT_H
+#define STAT_H
+#include <sys/types.h>
+#include <time.h>
+
+struct stat {
+  dev_t st_dev;            // Device ID of device containing file.
+  ino_t st_ino;            // File serial number.
+  mode_t st_mode;          // Mode of file (see below).
+  nlink_t st_nlink;        // Number of hard links to the file.
+  uid_t st_uid;            // User ID of file.
+  gid_t st_gid;            // Group ID of file.
+  dev_t st_rdev;           // Device ID (if file is character or block special).
+  off_t st_size;           // For regular files, the file size in bytes.
+                           // For symbolic links, the length in bytes of the
+                           // pathname contained in the symbolic link.
+                           // For a shared memory object, the length in bytes.
+                           // For a typed memory object, the length in bytes.
+                           // For other file types, the use of this field is
+                           // unspecified.
+  struct timespec st_atime; // Last data access timestamp.
+  struct timespec st_mtime; // Last data modification timestamp.
+  struct timespec st_ctime; // Last file status change timestamp.
+  blksize_t st_blksize;    // A file system-specific preferred I/O block size
+                           // for this object. In some file system types, this
+                           // may vary from file to file.
+  blkcnt_t st_blocks;      // Number of blocks allocated for this object.
+};
+int stat(const char *path, struct stat *buf);
+int mkdir(const char *path, mode_t mode);
+#endif
diff --git a/userland/libc/include/sys/statvfs.h b/userland/libc/include/sys/statvfs.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/statvfs.h
diff --git a/userland/libc/include/sys/syscall.h b/userland/libc/include/sys/syscall.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/syscall.h
diff --git a/userland/libc/include/sys/time.h b/userland/libc/include/sys/time.h
new file mode 100644
index 0000000..a675d9e
--- /dev/null
+++ b/userland/libc/include/sys/time.h
@@ -0,0 +1,41 @@
+#ifndef TIME_H
+#define TIME_H
+#include <stddef.h>
+#include <sys/types.h>
+#include <time.h>
+
+#define CLOCK_REALTIME 0
+
+struct tm {
+  int tm_sec;
+  int tm_min;
+  int tm_hour;
+  int tm_mday;
+  int tm_mon;
+  int tm_year;
+  int tm_wday;
+  int tm_yday;
+  int tm_isdst;
+  long __tm_gmtoff;
+  const char *__tm_zone;
+};
+
+typedef int clockid_t;
+struct timespec {
+  time_t tv_sec; // Seconds.
+  long tv_nsec;  // Nanoseconds.
+};
+
+struct timeval {
+  time_t tv_sec;
+  suseconds_t tv_usec;
+};
+
+time_t time(time_t *tloc);
+int clock_gettime(clockid_t clock_id, struct timespec *tp);
+struct tm *localtime(const time_t *timer);
+struct tm *gmtime(const time_t *timer);
+size_t strftime(char *restrict s, size_t maxsize, const char *restrict format,
+                const struct tm *restrict timeptr);
+int gettimeofday(struct timeval *tp, void *tzp);
+#endif
diff --git a/userland/libc/include/sys/times.h b/userland/libc/include/sys/times.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/times.h
diff --git a/userland/libc/include/sys/types.h b/userland/libc/include/sys/types.h
new file mode 100644
index 0000000..48c57f9
--- /dev/null
+++ b/userland/libc/include/sys/types.h
@@ -0,0 +1,28 @@
+#ifndef TYPES_H
+#define TYPES_H
+typedef unsigned int ino_t;
+
+typedef int mode_t;
+
+typedef int nlink_t;
+typedef int uid_t;
+typedef int gid_t;
+typedef int id_t;
+
+typedef int blkcnt_t;
+typedef int off_t;
+
+typedef int dev_t;
+typedef unsigned int fsblkcnt_t;
+typedef unsigned int fsfilcnt_t;
+typedef unsigned int ino_t;
+//typedef unsigned int size_t;
+
+typedef int blksize_t;
+typedef int pid_t;
+typedef int ssize_t;
+
+//typedef int clock_t;
+typedef int time_t;
+typedef unsigned int suseconds_t;
+#endif
diff --git a/userland/libc/include/sys/ucontext.h b/userland/libc/include/sys/ucontext.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/ucontext.h
diff --git a/userland/libc/include/sys/un.h b/userland/libc/include/sys/un.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/un.h
diff --git a/userland/libc/include/sys/utsname.h b/userland/libc/include/sys/utsname.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/utsname.h
diff --git a/userland/libc/include/sys/wait.h b/userland/libc/include/sys/wait.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/sys/wait.h
diff --git a/userland/libc/include/syscall.h b/userland/libc/include/syscall.h
new file mode 100644
index 0000000..caa7779
--- /dev/null
+++ b/userland/libc/include/syscall.h
@@ -0,0 +1,150 @@
+#ifndef SYSCALL_H
+#define SYSCALL_H
+#include "socket.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#define SYS_OPEN 0
+#define SYS_READ 1
+#define SYS_WRITE 2
+#define SYS_PREAD 3
+#define SYS_PWRITE 4
+#define SYS_FORK 5
+#define SYS_EXEC 6
+#define SYS_GETPID 7
+#define SYS_EXIT 8
+#define SYS_WAIT 9
+#define SYS_BRK 10
+#define SYS_SBRK 11
+#define SYS_PIPE 12
+#define SYS_DUP2 13
+#define SYS_CLOSE 14
+#define SYS_OPENPTY 15
+#define SYS_POLL 16
+#define SYS_MMAP 17
+#define SYS_ACCEPT 18
+#define SYS_BIND 19
+#define SYS_SOCKET 20
+#define SYS_SHM_OPEN 21
+#define SYS_FTRUNCATE 22
+#define SYS_STAT 23
+#define SYS_MSLEEP 24
+#define SYS_UPTIME 25
+
+int syscall(uint32_t eax, uint32_t ebx, uint32_t ecx, uint32_t edx,
+            uint32_t esi, uint32_t edi);
+int s_syscall(int sys);
+
+extern int errno;
+#define RC_ERRNO(_rc)                                                          \
+  {                                                                            \
+    int c = _rc;                                                               \
+    if (c < 0) {                                                               \
+      errno = -(c);                                                            \
+      return -1;                                                               \
+    }                                                                          \
+    return c;                                                                  \
+  }
+
+typedef int mode_t;
+
+typedef struct SYS_OPEN_PARAMS {
+  const char *file;
+  int flags;
+  int mode;
+} __attribute__((packed)) SYS_OPEN_PARAMS;
+
+typedef struct SYS_PREAD_PARAMS {
+  int fd;
+  void *buf;
+  size_t count;
+  size_t offset;
+} __attribute__((packed)) SYS_PREAD_PARAMS;
+
+typedef struct SYS_READ_PARAMS {
+  int fd;
+  void *buf;
+  size_t count;
+} __attribute__((packed)) SYS_READ_PARAMS;
+
+typedef struct SYS_PWRITE_PARAMS {
+  int fd;
+  const void *buf;
+  size_t count;
+  size_t offset;
+} __attribute__((packed)) SYS_PWRITE_PARAMS;
+
+typedef struct SYS_WRITE_PARAMS {
+  int fd;
+  const void *buf;
+  size_t count;
+} __attribute__((packed)) SYS_WRITE_PARAMS;
+
+typedef struct SYS_EXEC_PARAMS {
+  const char *path;
+  char **argv;
+} __attribute__((packed)) SYS_EXEC_PARAMS;
+
+typedef struct SYS_DUP2_PARAMS {
+  int org_fd;
+  int new_fd;
+} __attribute__((packed)) SYS_DUP2_PARAMS;
+
+typedef struct SYS_OPENPTY_PARAMS {
+  int *amaster;
+  int *aslave;
+  char *name;
+  /*const struct termios*/ void *termp;
+  /*const struct winsize*/ void *winp;
+} __attribute__((packed)) SYS_OPENPTY_PARAMS;
+
+typedef struct SYS_POLL_PARAMS {
+  struct pollfd *fds;
+  size_t nfds;
+  int timeout;
+} __attribute__((packed)) SYS_POLL_PARAMS;
+
+typedef struct SYS_MMAP_PARAMS {
+  void *addr;
+  size_t length;
+  int prot;
+  int flags;
+  int fd;
+  size_t offset;
+} __attribute__((packed)) SYS_MMAP_PARAMS;
+
+typedef struct SYS_SOCKET_PARAMS {
+  int domain;
+  int type;
+  int protocol;
+} __attribute__((packed)) SYS_SOCKET_PARAMS;
+
+typedef struct SYS_BIND_PARAMS {
+  int sockfd;
+  const struct sockaddr *addr;
+  socklen_t addrlen;
+} __attribute__((packed)) SYS_BIND_PARAMS;
+
+typedef struct SYS_ACCEPT_PARAMS {
+  int socket;
+  struct sockaddr *address;
+  socklen_t *address_len;
+} __attribute__((packed)) SYS_ACCEPT_PARAMS;
+
+typedef struct SYS_SHM_OPEN_PARAMS {
+  const char *name;
+  int oflag;
+  mode_t mode;
+} __attribute__((packed)) SYS_SHM_OPEN_PARAMS;
+
+typedef struct SYS_FTRUNCATE_PARAMS {
+  int fildes;
+  size_t length;
+} __attribute__((packed)) SYS_FTRUNCATE_PARAMS;
+
+typedef struct SYS_STAT_PARAMS {
+  const char *pathname;
+  struct stat *statbuf;
+} __attribute__((packed)) SYS_STAT_PARAMS;
+#endif
diff --git a/userland/libc/include/syslog.h b/userland/libc/include/syslog.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/syslog.h
diff --git a/userland/libc/include/termios.h b/userland/libc/include/termios.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/termios.h
diff --git a/userland/libc/include/time.h b/userland/libc/include/time.h
new file mode 100644
index 0000000..567e9ef
--- /dev/null
+++ b/userland/libc/include/time.h
@@ -0,0 +1,35 @@
+#ifndef TIME_H
+#define TIME_H
+#include <sys/types.h>
+#include <stddef.h>
+
+#define CLOCK_REALTIME 0
+
+struct tm {
+  int tm_sec;
+  int tm_min;
+  int tm_hour;
+  int tm_mday;
+  int tm_mon;
+  int tm_year;
+  int tm_wday;
+  int tm_yday;
+  int tm_isdst;
+  long __tm_gmtoff;
+  const char *__tm_zone;
+};
+
+typedef int clockid_t;
+struct timespec {
+  time_t tv_sec; // Seconds.
+  long tv_nsec;  // Nanoseconds.
+};
+
+time_t time(time_t *tloc);
+int clock_gettime(clockid_t clock_id, struct timespec *tp);
+struct tm *localtime(const time_t *timer);
+struct tm *gmtime(const time_t *timer);
+size_t strftime(char *restrict s, size_t maxsize,
+       const char *restrict format, const struct tm *restrict timeptr);
+char *ctime_r(const time_t *clock, char *buf);
+#endif
diff --git a/userland/libc/include/ubsan.h b/userland/libc/include/ubsan.h
new file mode 100644
index 0000000..dac5407
--- /dev/null
+++ b/userland/libc/include/ubsan.h
@@ -0,0 +1,79 @@
+#include <stdint.h>
+
+enum { type_kind_int = 0, type_kind_float = 1, type_unknown = 0xffff };
+
+struct type_descriptor {
+  uint16_t type_kind;
+  uint16_t type_info;
+  char type_name[1];
+};
+
+struct source_location {
+  const char *file_name;
+  union {
+    unsigned long reported;
+    struct {
+      uint32_t line;
+      uint32_t column;
+    };
+  };
+};
+
+struct OverflowData {
+  struct source_location location;
+  struct type_descriptor *type;
+};
+
+struct type_mismatch_data {
+  struct source_location location;
+  struct type_descriptor *type;
+  unsigned long alignment;
+  unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_v1 {
+  struct source_location location;
+  struct type_descriptor *type;
+  unsigned char log_alignment;
+  unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_common {
+  struct source_location *location;
+  struct type_descriptor *type;
+  unsigned long alignment;
+  unsigned char type_check_kind;
+};
+
+struct nonnull_arg_data {
+  struct source_location location;
+  struct source_location attr_location;
+  int arg_index;
+};
+
+struct OutOfBoundsData {
+  struct source_location location;
+  struct type_descriptor *array_type;
+  struct type_descriptor *index_type;
+};
+
+struct ShiftOutOfBoundsData {
+  struct source_location location;
+  struct type_descriptor *lhs_type;
+  struct type_descriptor *rhs_type;
+};
+
+struct unreachable_data {
+  struct source_location location;
+};
+
+struct invalid_value_data {
+  struct source_location location;
+  struct type_descriptor *type;
+};
+
+struct alignment_assumption_data {
+  struct source_location location;
+  struct source_location assumption_location;
+  struct type_descriptor *type;
+};
diff --git a/userland/libc/include/unistd.h b/userland/libc/include/unistd.h
new file mode 100644
index 0000000..e43dc33
--- /dev/null
+++ b/userland/libc/include/unistd.h
@@ -0,0 +1,24 @@
+#ifndef UNISTD_H
+#define UNISTD_H
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#define STDIN_FILENO 0
+
+extern int opterr, optind, optopt;
+extern char *optarg;
+
+int close(int fildes);
+int ftruncate(int fildes, uint64_t length);
+int execv(char *path, char **argv);
+int pipe(int fd[2]);
+int dup2(int org_fd, int new_fd);
+int getopt(int argc, char *const argv[], const char *optstring);
+pid_t getpid(void);
+int unlink(const char *path);
+int execvp(const char *file, char *const argv[]);
+void _exit(int status);
+void msleep(uint32_t ms); // not standard
+uint32_t uptime(void); // not standard
+#endif
diff --git a/userland/libc/include/utime.h b/userland/libc/include/utime.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/utime.h
diff --git a/userland/libc/include/wchar.h b/userland/libc/include/wchar.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/wchar.h
diff --git a/userland/libc/include/wctype.h b/userland/libc/include/wctype.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/include/wctype.h
diff --git a/userland/libc/input.h b/userland/libc/input.h
new file mode 100644
index 0000000..a6602f5
--- /dev/null
+++ b/userland/libc/input.h
@@ -0,0 +1,9 @@
+#ifndef INPUT_H
+#define INPUT_H
+#include <stdint.h>
+
+struct input_event {
+  uint16_t key;
+  uint8_t status;
+};
+#endif
diff --git a/userland/libc/inttypes.h b/userland/libc/inttypes.h
new file mode 100644
index 0000000..0bf39d1
--- /dev/null
+++ b/userland/libc/inttypes.h
@@ -0,0 +1,5 @@
+#include <stdint.h>
+
+// FIXME: These are not correct
+#define PRId64 "d"
+#define PRId32 "d"
diff --git a/userland/libc/isspace.c b/userland/libc/isspace.c
new file mode 100644
index 0000000..9ba2766
--- /dev/null
+++ b/userland/libc/isspace.c
@@ -0,0 +1,5 @@
+#include <ctype.h>
+
+int isspace(int c) {
+    return c == ' ' || (unsigned)c-'\t' < 5;
+}
diff --git a/userland/libc/libc.c b/userland/libc/libc.c
new file mode 100644
index 0000000..259ef0c
--- /dev/null
+++ b/userland/libc/libc.c
@@ -0,0 +1,287 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <syscall.h>
+
+int errno;
+
+char *errno_strings[] = {
+    "",
+    "Argument list too long.",
+    "Permission denied.",
+    "Address in use.",
+    "Address not available.",
+    "Address family not supported.",
+    "Resource unavailable, try again (may be the same value as [EWOULDBLOCK]).",
+    "Connection already in progress.",
+    "Bad file descriptor.",
+    "Bad message.",
+    "Device or resource busy.",
+    "Operation canceled.",
+    "No child processes.",
+    "Connection aborted.",
+    "Connection refused.",
+    "Connection reset.",
+    "Resource deadlock would occur.",
+    "Destination address required.",
+    "Mathematics argument out of domain of function.",
+    "Reserved.",
+    "File exists.",
+    "Bad address.",
+    "File too large.",
+    "Host is unreachable.",
+    "Identifier removed.",
+    "Illegal byte sequence.",
+    "Operation in progress.",
+    "Interrupted function.",
+    "Invalid argument.",
+    "I/O error.",
+    "Socket is connected.",
+    "Is a directory.",
+    "Too many levels of symbolic links.",
+    "File descriptor value too large.",
+    "Too many links.",
+    "Message too large.",
+    "Reserved.",
+    "Filename too long.",
+    "Network is down.",
+    "Connection aborted by network.",
+    "Network unreachable.",
+    "Too many files open in system.",
+    "No buffer space available.",
+    "No message is available on the STREAM head read "
+    "queue. [Option End]",
+    "No such device.",
+    "No such file or directory.",
+    "Executable file format error.",
+    "No locks available.",
+    "Reserved.",
+    "Not enough space.",
+    "No message of the desired type.",
+    "Protocol not available.",
+    "No space left on device.",
+    "No STREAM resources.",
+    "Not a STREAM.",
+    "Functionality not supported.",
+    "The socket is not connected.",
+    "Not a directory or a symbolic link to a directory.",
+    "Directory not empty.",
+    "State not recoverable.",
+    "Not a socket.",
+    "Not supported (may be the same value as [EOPNOTSUPP]).",
+    "Inappropriate I/O control operation.",
+    "No such device or address.",
+    "Operation not supported on socket (may be the same value as [ENOTSUP]).",
+    "Value too large to be stored in data type.",
+    "Previous owner died.",
+    "Operation not permitted.",
+    "Broken pipe.",
+    "Protocol error.",
+    "Protocol not supported.",
+    "Protocol wrong type for socket.",
+    "Result too large.",
+    "Read-only file system.",
+    "Invalid seek.",
+    "No such process.",
+    "Reserved.",
+    "Stream ioctl() timeout. [Option End]",
+    "Connection timed out.",
+    "Text file busy.",
+    "Operation would block (may be the same value as [EAGAIN]).",
+    "Cross-device link. ",
+};
+
+#define ASSERT_NOT_REACHED assert(0)
+
+#define TAB_SIZE 8
+
+// Functions preserve the registers ebx, esi, edi, ebp, and esp; while
+// eax, ecx, edx are scratch registers.
+
+// Syscall: eax ebx ecx edx esi edi
+int syscall(uint32_t eax, uint32_t ebx, uint32_t ecx, uint32_t edx,
+            uint32_t esi, uint32_t edi) {
+  asm volatile("push %edi\n"
+               "push %esi\n"
+               "push %ebx\n"
+               "mov 0x1C(%ebp), %edi\n"
+               "mov 0x18(%ebp), %esi\n"
+               "mov 0x14(%ebp), %edx\n"
+               "mov 0x10(%ebp), %ecx\n"
+               "mov 0xc(%ebp), %ebx\n"
+               "mov 0x8(%ebp), %eax\n"
+               "int $0x80\n"
+               "pop %ebx\n"
+               "pop %esi\n"
+               "pop %edi\n");
+}
+
+int pipe(int fd[2]) { return syscall(SYS_PIPE, fd, 0, 0, 0, 0); }
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/strerror.html
+char *strerror(int errnum) {
+  // The strerror() function shall map the error number in errnum to a
+  // locale-dependent error message string and shall return a pointer to it.
+  return errno_strings[errnum];
+}
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/perror.html
+void perror(const char *s) {
+  // The perror() function shall map the error number accessed through the
+  // symbol errno to a language-dependent error message, which shall be written
+  // to the standard error stream as follows:
+
+  // (First (if s is not a null pointer and the character pointed to
+  // by s is not the null byte),
+  if (s && *s != '\0') {
+    // the string pointed to by s
+    // followed by a <colon> and a <space>.
+    printf("%s: ", s);
+  }
+
+  // Then an error message string followed by a <newline>.
+  // The contents of the error message strings shall be the same as those
+  // returned by strerror() with argument errno.
+  printf("%s\n", strerror(errno));
+}
+
+int open(const char *file, int flags, int mode) {
+  struct SYS_OPEN_PARAMS args = {
+      .file = file,
+      .flags = flags,
+      .mode = mode,
+  };
+  RC_ERRNO(syscall(SYS_OPEN, &args, 0, 0, 0, 0));
+}
+
+int close(int fd) { return syscall(SYS_CLOSE, (void *)fd, 0, 0, 0, 0); }
+
+int execv(char *path, char **argv) {
+  struct SYS_EXEC_PARAMS args = {.path = path, .argv = argv};
+  return syscall(SYS_EXEC, &args, 0, 0, 0, 0);
+}
+/*
+int syscall(int sys, void *args) {
+  asm volatile("push %ebx\n"
+               "mov 0xc(%ebp), %ebx\n"
+               "mov 0x8(%ebp), %eax\n"
+               "int $0x80\n"
+               "pop %ebx\n");
+}*/
+
+int s_syscall(int sys) {
+  asm volatile("movl %0, %%eax\n"
+               "int $0x80\n" ::"r"((uint32_t)sys));
+}
+
+int write(int fd, const char *buf, size_t count) {
+	/*
+  struct SYS_WRITE_PARAMS args = {
+      .fd = fd,
+      .buf = buf,
+      .count = count,
+  };*/
+  return syscall(SYS_WRITE, fd, buf, count, 0, 0);
+}
+
+int pwrite(int fd, const char *buf, size_t count, size_t offset) {
+  struct SYS_PWRITE_PARAMS args = {
+      .fd = fd,
+      .buf = buf,
+      .count = count,
+      .offset = offset,
+  };
+  return syscall(SYS_PWRITE, &args, 0, 0, 0, 0);
+}
+
+int wait(int *stat_loc) { return syscall(SYS_WAIT, stat_loc, 0, 0, 0, 0); }
+
+void exit(int status) { syscall(SYS_EXIT, (void *)status, 0, 0, 0, 0); }
+
+int pread(int fd, void *buf, size_t count, size_t offset) {
+  struct SYS_PREAD_PARAMS args = {
+      .fd = fd,
+      .buf = buf,
+      .count = count,
+      .offset = offset,
+  };
+  RC_ERRNO(syscall(SYS_PREAD, &args, 0, 0, 0, 0));
+}
+
+int read(int fd, void *buf, size_t count) {
+  struct SYS_READ_PARAMS args = {
+      .fd = fd,
+      .buf = buf,
+      .count = count,
+  };
+  RC_ERRNO(syscall(SYS_READ, &args, 0, 0, 0, 0));
+}
+
+int dup2(int org_fd, int new_fd) {
+  struct SYS_DUP2_PARAMS args = {
+      .org_fd = org_fd,
+      .new_fd = new_fd,
+  };
+  RC_ERRNO(syscall(SYS_DUP2, &args, 0, 0, 0, 0));
+}
+
+int fork(void) { return s_syscall(SYS_FORK); }
+
+void dputc(int fd, const char c) { pwrite(fd, &c, 1, 0); }
+
+int brk(void *addr) { return syscall(SYS_BRK, addr, 0, 0, 0, 0); }
+
+void *sbrk(intptr_t increment) {
+  return (void *)syscall(SYS_SBRK, (void *)increment, 0, 0, 0, 0);
+}
+
+int poll(struct pollfd *fds, size_t nfds, int timeout) {
+  SYS_POLL_PARAMS args = {
+      .fds = fds,
+      .nfds = nfds,
+      .timeout = timeout,
+  };
+  RC_ERRNO(syscall(SYS_POLL, &args, 0, 0, 0, 0));
+}
+
+int socket(int domain, int type, int protocol) {
+  SYS_SOCKET_PARAMS args = {
+      .domain = domain,
+      .type = type,
+      .protocol = protocol,
+  };
+  RC_ERRNO(syscall(SYS_SOCKET, &args, 0, 0, 0, 0));
+}
+
+int accept(int socket, struct sockaddr *address, socklen_t *address_len) {
+  SYS_ACCEPT_PARAMS args = {
+      .socket = socket,
+      .address = address,
+      .address_len = address_len,
+  };
+  RC_ERRNO(syscall(SYS_ACCEPT, &args, 0, 0, 0, 0));
+}
+
+int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
+  SYS_BIND_PARAMS args = {
+      .sockfd = sockfd,
+      .addr = addr,
+      .addrlen = addrlen,
+  };
+  RC_ERRNO(syscall(SYS_BIND, &args, 0, 0, 0, 0));
+}
+
+int shm_open(const char *name, int oflag, mode_t mode) {
+  SYS_SHM_OPEN_PARAMS args = {
+      .name = name,
+      .oflag = oflag,
+      .mode = mode,
+  };
+  RC_ERRNO(syscall(SYS_SHM_OPEN, &args, 0, 0, 0, 0));
+}
+
+int ftruncate(int fildes, uint64_t length) {
+  SYS_FTRUNCATE_PARAMS args = {.fildes = fildes, .length = length};
+  RC_ERRNO(syscall(SYS_FTRUNCATE, &args, 0, 0, 0, 0));
+}
diff --git a/userland/libc/libgen/basename.c b/userland/libc/libgen/basename.c
new file mode 100644
index 0000000..a0a8adb
--- /dev/null
+++ b/userland/libc/libgen/basename.c
@@ -0,0 +1,45 @@
+#include <libgen.h>
+#include <stddef.h>
+
+/*
+The basename() function shall take the pathname pointed to by path and
+return a pointer to the final component of the pathname, deleting any
+trailing '/' characters.
+
+
+The basename() function may modify the string pointed to by path, and
+may return a pointer to internal storage. The returned pointer might be
+invalidated or the storage might be overwritten by a subsequent call to
+basename(). The returned pointer might also be invalidated if the
+calling thread is terminated.
+*/
+
+char *basename_empty_return_value = ".";
+char *basename_slash_return_value = "/";
+char *basename(char *path) {
+  // If path is a null pointer or points to an empty string, basename()
+  // shall return a pointer to the string ".".
+  if (NULL == path || '\0' == *path)
+    return basename_empty_return_value;
+
+  char *start = path;
+  // Move the string to the end
+  for (; *path; path++)
+    ;
+  if (start == path)
+    return start;
+  path--;
+  if ('/' == *path) // Trailing slash
+    *path = '\0';
+  // Loop until next slash is found
+  for (; path != start && '/' != *path; path--)
+    ;
+  // If the string pointed to by path consists entirely of the '/' character,
+  // basename() shall return a pointer to the string "/". If the string
+  // pointed to by path is exactly "//", it is implementation-defined whether
+  //'/' or "//" is returned.
+  path++;
+  if ('\0' == *path)
+    return basename_slash_return_value;
+  return path;
+}
diff --git a/userland/libc/libgen/dirname.c b/userland/libc/libgen/dirname.c
new file mode 100644
index 0000000..fb3c813
--- /dev/null
+++ b/userland/libc/libgen/dirname.c
@@ -0,0 +1,44 @@
+#include <libgen.h>
+
+char *dirname_empty_return_value = ".";
+char *dirname_slash_return_value = "/";
+char *dirname(char *path) {
+  // If path is a null pointer or points to an empty string,
+  // dirname() shall return a pointer to the string "."
+  if (!path)
+    return dirname_empty_return_value;
+  if ('\0' == *path)
+    return dirname_empty_return_value;
+
+  char *start = path;
+  for (; *path; path++)
+    ;
+  path--;
+  if ('/' == *path) {
+    if (start == path)
+      return path;
+    path--;
+  }
+
+  for (; path != start && '/' != *path; path--)
+    ;
+  // If path does not contain a '/', then dirname() shall return a pointer to
+  // the string ".".
+  if ('/' != *path)
+    return dirname_empty_return_value;
+
+  if (path == start)
+    return dirname_slash_return_value;
+
+  *path = '\0';
+  path--;
+
+  for (; path != start && '/' != *path; path--)
+    ;
+
+  if ('/' != *path)
+    return dirname_empty_return_value;
+
+  path++;
+  return path;
+}
diff --git a/userland/libc/limits.h b/userland/libc/limits.h
new file mode 100644
index 0000000..0c9389a
--- /dev/null
+++ b/userland/libc/limits.h
@@ -0,0 +1,2 @@
+#define PATH_MAX 256
+#define FILENAME_MAX PATH_MAX
diff --git a/userland/libc/malloc/malloc.c b/userland/libc/malloc/malloc.c
new file mode 100644
index 0000000..f351291
--- /dev/null
+++ b/userland/libc/malloc/malloc.c
@@ -0,0 +1,232 @@
+#include <assert.h>
+#include <errno.h>
+#include <malloc/malloc.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#define NEW_ALLOC_SIZE 0x20000
+#define MALLOC_HEADER_MAGIC 0x1337F00D
+#define MALLOC_HEADER_PAD 0x11223344
+
+#define IS_FREE (1 << 0)
+#define IS_FINAL (1 << 1)
+
+typedef struct MallocHeader {
+  uint32_t magic;
+  uint32_t size;
+  uint8_t flags;
+  struct MallocHeader *n;
+} MallocHeader;
+
+size_t max(size_t a, size_t b) { return (a > b) ? a : b; }
+
+//;size_t min(size_t a, size_t b) { return (a < b) ? a : b; }
+
+uint64_t delta_page(uint64_t a) { return 0x1000 - (a % 0x1000); }
+
+MallocHeader *head = NULL;
+MallocHeader *final = NULL;
+uint32_t total_heap_size = 0;
+
+int init_heap(void) {
+  head = (MallocHeader *)sbrk(NEW_ALLOC_SIZE);
+  if ((void *)-1 == head) {
+    perror("sbrk");
+    exit(1);
+  }
+  total_heap_size += NEW_ALLOC_SIZE - sizeof(MallocHeader);
+  head->magic = MALLOC_HEADER_MAGIC;
+  head->size = NEW_ALLOC_SIZE - sizeof(MallocHeader);
+  head->flags = IS_FREE | IS_FINAL;
+  head->n = NULL;
+  final = head;
+  return 1;
+}
+
+int add_heap_memory(size_t min_desired) {
+  min_desired += sizeof(MallocHeader) + 0x1000;
+  size_t allocation_size = max(min_desired, NEW_ALLOC_SIZE);
+  allocation_size += delta_page(allocation_size);
+  void *p;
+  if ((void *)(-1) == (p = (void *)sbrk(allocation_size))) {
+    perror("sbrk");
+    return 0;
+  }
+  total_heap_size += allocation_size - sizeof(MallocHeader);
+  void *e = final;
+  e = (void *)((uint32_t)e + final->size);
+  if (p == e) {
+    final->size += allocation_size - sizeof(MallocHeader);
+    return 1;
+  }
+  MallocHeader *new_entry = p;
+  new_entry->magic = MALLOC_HEADER_MAGIC;
+  new_entry->size = allocation_size - sizeof(MallocHeader);
+  new_entry->flags = IS_FREE | IS_FINAL;
+  new_entry->n = NULL;
+  final->n = new_entry;
+  final = new_entry;
+  return 1;
+}
+
+MallocHeader *next_header(MallocHeader *a) { return a->n; }
+
+MallocHeader *next_close_header(MallocHeader *a) {
+  if (!a) {
+    printf("next close header fail\n");
+    for (;;)
+      ;
+  }
+  if (a->flags & IS_FINAL)
+    return NULL;
+  return next_header(a);
+}
+
+MallocHeader *find_free_entry(uint32_t s, int align) {
+  // A new header is required as well as the newly allocated chunk
+  if (!head)
+    init_heap();
+  MallocHeader *p = head;
+  for (; p; p = next_header(p)) {
+    if (!(p->flags & IS_FREE))
+      continue;
+    uint64_t required_size = s;
+    if (align) {
+      void *addy = p;
+      addy = (void *)((uint32_t)addy + sizeof(MallocHeader));
+      uint64_t d = delta_page((uint32_t)addy);
+      if (d < sizeof(MallocHeader) && d != 0)
+        continue;
+      required_size += d;
+    }
+    if (p->size < required_size)
+      continue;
+    return p;
+  }
+  return NULL;
+}
+
+void merge_headers(MallocHeader *b) {
+  if (!(b->flags & IS_FREE))
+    return;
+
+  MallocHeader *n = next_close_header(b);
+  if (!n)
+    return;
+
+  if (n > 0xf58c0820 - 0x8 && n < 0xf58c0820 + 0x8) {
+    printf("b: %x\n", b);
+    printf("b->n: %x\n", b->n);
+    asm("hlt");
+    assert(0);
+  }
+  if (!(n->flags & IS_FREE))
+    return;
+
+  // Remove the next header and just increase the newly freed header
+  b->size += n->size;
+  b->flags |= n->flags & IS_FINAL;
+  b->n = n->n;
+  if (n == final)
+    final = b;
+}
+
+extern int errno;
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+void *int_malloc(size_t s, int align) {
+  if (!head)
+    init_heap();
+  size_t n = s;
+  MallocHeader *free_entry = find_free_entry(s, align);
+  if (!free_entry) {
+    if (!add_heap_memory(s)) {
+      errno = ENOMEM;
+      printf("ENOMEM\n");
+      return NULL;
+    }
+    return int_malloc(s, align);
+  }
+
+  void *rc = (void *)((uint32_t)free_entry + sizeof(MallocHeader));
+
+  if (align) {
+    uint64_t d = delta_page((uint32_t)rc);
+    n = d;
+    n -= sizeof(MallocHeader);
+  }
+
+  // Create a new header
+  MallocHeader *new_entry =
+      (MallocHeader *)((uint32_t)free_entry + n + sizeof(MallocHeader));
+  new_entry->magic = MALLOC_HEADER_MAGIC;
+  new_entry->flags = free_entry->flags;
+  new_entry->n = free_entry->n;
+  new_entry->size = free_entry->size - n - sizeof(MallocHeader);
+  if (free_entry == final)
+    final = new_entry;
+  merge_headers(new_entry);
+
+  // Modify the free entry
+  free_entry->size = n;
+  free_entry->flags = 0;
+  free_entry->n = new_entry;
+
+  if (align && ((uint32_t)rc % 0x1000) != 0) {
+    void *c = int_malloc(s, 1);
+    free(rc);
+    rc = c;
+    return rc;
+  }
+  return rc;
+}
+
+void *malloc(size_t s) { return int_malloc(s + 1, 0); }
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+void *calloc(size_t nelem, size_t elsize) {
+  // The calloc() function shall allocate unused space for an array of
+  // nelem elements each of whose size in bytes is elsize.
+  size_t alloc_size = nelem * elsize;
+  void *rc = malloc(alloc_size);
+  // The space shall be initialized to all bits 0.
+  memset(rc, 0, alloc_size);
+  return rc;
+}
+
+size_t get_mem_size(void *ptr) {
+  if (!ptr)
+    return 0;
+  return ((MallocHeader *)(ptr - sizeof(MallocHeader)))->size;
+}
+
+void *realloc(void *ptr, size_t size) {
+  void *rc = malloc(size);
+  if (!rc)
+    return NULL;
+  size_t l = get_mem_size(ptr);
+  size_t to_copy = min(l, size);
+  memcpy(rc, ptr, to_copy);
+  free(ptr);
+  return rc;
+}
+
+void free(void *p) {
+  if (!p)
+    return;
+  // FIXME: This assumes that p is at the start of a allocated area.
+  // Is this a assumption that can be made?
+  MallocHeader *h = (MallocHeader *)((uint32_t)p - sizeof(MallocHeader));
+  if (MALLOC_HEADER_MAGIC != h->magic) {
+    printf("h->magic: %x\n", h->magic);
+    printf("&h->magic: %x\n", &(h->magic));
+    assert(0);
+  }
+  if (h->flags & IS_FREE)
+    return;
+
+  h->flags |= IS_FREE;
+  merge_headers(h);
+}
diff --git a/userland/libc/malloc/malloc.h b/userland/libc/malloc/malloc.h
new file mode 100644
index 0000000..082d8ad
--- /dev/null
+++ b/userland/libc/malloc/malloc.h
@@ -0,0 +1,9 @@
+#ifndef MALLOC_H
+#define MALLOC_H
+#include <stdint.h>
+#include <stddef.h>
+
+void *malloc(size_t s);
+void *calloc(size_t nelem, size_t elsize);
+void free(void *p);
+#endif
diff --git a/userland/libc/malloc/oldmalloc.c b/userland/libc/malloc/oldmalloc.c
new file mode 100644
index 0000000..042049d
--- /dev/null
+++ b/userland/libc/malloc/oldmalloc.c
@@ -0,0 +1,136 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "../errno.h"
+#include <stdint.h>
+#include <stddef.h>
+#include <string.h>
+
+#define NEW_ALLOC_SIZE 0x1000
+
+#define IS_FREE (1 << 0)
+#define IS_FINAL (1 << 1)
+
+typedef struct MallocHeader {
+  uint32_t size;
+  uint8_t flags;
+} MallocHeader;
+
+MallocHeader *head = NULL;
+MallocHeader *final = NULL;
+uint32_t total_heap_size = 0;
+
+int init_heap(void) {
+  head = sbrk(NEW_ALLOC_SIZE);
+  if ((void *)-1 == head) {
+    // perror("sbrk");
+    return 0;
+  }
+  total_heap_size += NEW_ALLOC_SIZE;
+  head->size = NEW_ALLOC_SIZE;
+  head->flags = IS_FREE | IS_FINAL;
+  final = head;
+  return 1;
+}
+
+int add_heap_memory(void) {
+  if ((void *)-1 == sbrk(NEW_ALLOC_SIZE)) {
+    // perror("sbrk");
+    return 0;
+  }
+  total_heap_size += NEW_ALLOC_SIZE;
+  final->size += NEW_ALLOC_SIZE;
+  return 1;
+}
+
+MallocHeader *next_header(MallocHeader *a) {
+  if (a->flags & IS_FINAL)
+    return NULL;
+  return ((void *)a) + a->size;
+}
+
+MallocHeader *find_free_entry(uint32_t s) {
+  // A new header is required as well as the newly allocated chunk
+  s += sizeof(MallocHeader);
+  if (!head)
+    init_heap();
+  MallocHeader *p = head;
+  for (; p; p = next_header(p)) {
+    if (!(p->flags & IS_FREE))
+      continue;
+    if (p->size < s)
+      continue;
+    return p;
+  }
+  return NULL;
+}
+
+void merge_headers(MallocHeader *b) {
+  if (!(b->flags & IS_FREE))
+    return;
+
+  MallocHeader *n = next_header(b);
+  if (!n)
+    return;
+
+  if (!(n->flags & IS_FREE))
+    return;
+
+  // Remove the next header and just increase the newly freed header
+  b->size += n->size;
+  b->flags |= n->flags & IS_FINAL;
+  if (b->flags & IS_FINAL)
+    final = b;
+}
+
+extern int errno;
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+void *malloc(size_t s) {
+  if(s == 0)
+      s = 1;
+
+  MallocHeader *free_entry = find_free_entry(s);
+  if (!free_entry) {
+    if (!add_heap_memory()) {
+        errno = ENOMEM;
+      return NULL;
+    }
+    return malloc(s);
+  }
+
+  // Create a new header
+  MallocHeader *new_entry = ((void *)free_entry) + s;
+  new_entry->flags |= IS_FREE;
+  new_entry->size = free_entry->size - s - sizeof(MallocHeader);
+  new_entry->flags |= free_entry->flags & IS_FINAL;
+  if (new_entry->flags & IS_FINAL)
+    final = new_entry;
+  merge_headers(new_entry);
+
+  // Modify the free entry
+  free_entry->size = s;
+  free_entry->flags = 0;
+
+  return ((void *)free_entry) + sizeof(MallocHeader);
+}
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+void *calloc(size_t nelem, size_t elsize) {
+    // The calloc() function shall allocate unused space for an array of
+    // nelem elements each of whose size in bytes is elsize.
+    size_t alloc_size = nelem*elsize;
+    void *rc = malloc(alloc_size);
+    // The space shall be initialized to all bits 0.
+    memset(rc, 0, alloc_size);
+    return rc;
+}
+
+void free(void *p) {
+  // FIXME: This assumes that p is at the start of a allocated area.
+  // Is this a assumption that can be made?
+  MallocHeader *h = p - sizeof(MallocHeader);
+  if (h->flags & IS_FREE)
+    return;
+
+  h->flags |= IS_FREE;
+  merge_headers(h);
+}
diff --git a/userland/libc/math.h b/userland/libc/math.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/math.h
diff --git a/userland/libc/memset.c b/userland/libc/memset.c
new file mode 100644
index 0000000..51910e9
--- /dev/null
+++ b/userland/libc/memset.c
@@ -0,0 +1,15 @@
+#include <stddef.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+void *memset(void *s, int c, size_t n) {
+  // The memset() function shall copy c (converted to an unsigned
+  // char) into each of the first n bytes of the object pointed to by
+  // s.
+
+  unsigned char *p = s;
+  for (; n > 0; n--, p++)
+    *p = (unsigned char)c;
+
+  // The memset() function shall return s
+  return s;
+}
diff --git a/userland/libc/mmap.c b/userland/libc/mmap.c
new file mode 100644
index 0000000..06b79bd
--- /dev/null
+++ b/userland/libc/mmap.c
@@ -0,0 +1,19 @@
+#include <syscall.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+extern int errno;
+
+void *mmap(void *addr, size_t length, int prot, int flags, int fd,
+           size_t offset) {
+  SYS_MMAP_PARAMS args = {
+      .addr = addr,
+      .length = length,
+      .prot = prot,
+      .flags = flags,
+      .fd = fd,
+      .offset = offset,
+  };
+//  return (void*)syscall(SYS_MMAP, &args);
+  RC_ERRNO(syscall(SYS_MMAP, &args));
+}
diff --git a/userland/libc/poll.h b/userland/libc/poll.h
new file mode 100644
index 0000000..88e98b3
--- /dev/null
+++ b/userland/libc/poll.h
@@ -0,0 +1,16 @@
+#ifndef POLL_H
+#define POLL_H
+#include <stddef.h>
+
+#define POLLIN (1 << 0)
+#define POLLPRI (1 << 1)
+#define POLLOUT (1 << 2)
+
+struct pollfd {
+    int fd;
+    short events;
+    short revents;
+};
+
+int poll(struct pollfd *fds, size_t nfds, int timeout);
+#endif
diff --git a/userland/libc/pty.c b/userland/libc/pty.c
new file mode 100644
index 0000000..b7ddf00
--- /dev/null
+++ b/userland/libc/pty.c
@@ -0,0 +1,15 @@
+#include "pty.h"
+#include "syscall.h"
+
+int openpty(int *amaster, int *aslave, char *name,
+                    /*const struct termios*/ void *termp,
+                    /*const struct winsize*/ void *winp) {
+ SYS_OPENPTY_PARAMS args = {
+    .amaster = amaster,
+    .aslave = aslave,
+    .name = name,
+    .termp = termp,
+    .winp = winp,
+ };
+ syscall(SYS_OPENPTY, &args, 0, 0, 0, 0);
+}
diff --git a/userland/libc/pty.h b/userland/libc/pty.h
new file mode 100644
index 0000000..b8ce978
--- /dev/null
+++ b/userland/libc/pty.h
@@ -0,0 +1,6 @@
+#ifndef PTY_H
+#define PTY_H
+int openpty(int *amaster, int *aslave, char *name,
+                    /*const struct termios*/ void *termp,
+                    /*const struct winsize*/ void *winp);
+#endif
diff --git a/userland/libc/setjmp/longjmp.s b/userland/libc/setjmp/longjmp.s
new file mode 100644
index 0000000..8188f06
--- /dev/null
+++ b/userland/libc/setjmp/longjmp.s
@@ -0,0 +1,16 @@
+.global _longjmp
+.global longjmp
+.type _longjmp,@function
+.type longjmp,@function
+_longjmp:
+longjmp:
+	mov  4(%esp),%edx
+	mov  8(%esp),%eax
+	cmp       $1,%eax
+	adc       $0, %al
+	mov   (%edx),%ebx
+	mov  4(%edx),%esi
+	mov  8(%edx),%edi
+	mov 12(%edx),%ebp
+	mov 16(%edx),%esp
+	jmp *20(%edx)
diff --git a/userland/libc/setjmp/setjmp.s b/userland/libc/setjmp/setjmp.s
new file mode 100644
index 0000000..4d19cf8
--- /dev/null
+++ b/userland/libc/setjmp/setjmp.s
@@ -0,0 +1,23 @@
+.global ___setjmp
+.hidden ___setjmp
+.global __setjmp
+.global _setjmp
+.global setjmp
+.type __setjmp,@function
+.type _setjmp,@function
+.type setjmp,@function
+___setjmp:
+__setjmp:
+_setjmp:
+setjmp:
+	mov 4(%esp), %eax
+	mov    %ebx, (%eax)
+	mov    %esi, 4(%eax)
+	mov    %edi, 8(%eax)
+	mov    %ebp, 12(%eax)
+	lea 4(%esp), %ecx
+	mov    %ecx, 16(%eax)
+	mov  (%esp), %ecx
+	mov    %ecx, 20(%eax)
+	xor    %eax, %eax
+	ret
diff --git a/userland/libc/socket.h b/userland/libc/socket.h
new file mode 100644
index 0000000..5e86b45
--- /dev/null
+++ b/userland/libc/socket.h
@@ -0,0 +1,41 @@
+#include <stddef.h>
+#include <stdint.h>
+
+#define AF_UNIX 0
+#define AF_LOCAL AF_UNIX
+
+#define INADDR_ANY 0
+
+typedef struct {
+  int domain;
+  int type;
+  int protocol;
+
+  // UNIX socket
+  char *path;
+  int incoming_fd;
+} SOCKET;
+
+typedef struct {
+  char *path;
+  SOCKET *s;
+} OPEN_UNIX_SOCKET;
+
+typedef uint32_t in_addr_t;
+typedef uint16_t in_port_t;
+typedef unsigned int sa_family_t;
+typedef uint32_t socklen_t;
+
+struct sockaddr {
+  sa_family_t sa_family; /* Address family */
+  char *sa_data;         /* Socket address */
+};
+
+struct sockaddr_un {
+  sa_family_t sun_family; /* Address family */
+  char *sun_path;         /* Socket pathname */
+};
+
+int socket(int domain, int type, int protocol);
+int accept(int socket, struct sockaddr *address, socklen_t *address_len);
+int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
diff --git a/userland/libc/stdio.h b/userland/libc/stdio.h
new file mode 100644
index 0000000..38aaf22
--- /dev/null
+++ b/userland/libc/stdio.h
@@ -0,0 +1,95 @@
+#ifndef STDIO_H
+#define STDIO_H
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
+
+// FIXME: Most of these should probably not be here. But I am too lazy
+// to fix it right now. This is futures mees problem to deal wth.
+
+#define EOF (-1)
+
+#define SEEK_SET 0
+#define SEEK_CUR 1
+#define SEEK_END 2
+
+typedef struct __IO_FILE FILE;
+struct __IO_FILE {
+  size_t (*write)(FILE *, const unsigned char *, size_t);
+  size_t (*read)(FILE *, unsigned char *, size_t);
+  int (*seek)(FILE *, long, int);
+  long offset_in_file;
+  int buffered_char;
+  int has_buffered_char;
+  uint8_t is_eof;
+  uint8_t has_error;
+  uint64_t file_size;
+  void *cookie;
+};
+
+size_t write_fd(FILE *f, const unsigned char *s, size_t l);
+size_t read_fd(FILE *f, unsigned char *s, size_t l);
+int seek_fd(FILE *stream, long offset, int whence);
+
+typedef struct {
+  int fd;
+} FILE_FD_COOKIE;
+
+extern FILE __stdin_FILE;
+extern FILE __stdout_FILE;
+extern FILE __stderr_FILE;
+
+#define stdin (&__stdin_FILE)
+#define stdout (&__stdout_FILE)
+//#define stderr (&__stderr_FILE)
+#define stderr (&__stdout_FILE)
+
+typedef int mode_t;
+
+void perror(const char *s);
+
+int putchar(int c);
+int puts(const char *s);
+int brk(void *addr);
+void *sbrk(intptr_t increment);
+int write(int fd, const char *buf, size_t count);
+int pwrite(int fd, const char *buf, size_t count, size_t offset);
+int printf(const char *format, ...);
+int pread(int fd, void *buf, size_t count, size_t offset);
+int read(int fd, void *buf, size_t count);
+int fork(void);
+int memcmp(const void *s1, const void *s2, size_t n);
+int wait(int *stat_loc);
+void exit(int status);
+void *memcpy(void *dest, const void *src, uint32_t n);
+int shm_open(const char *name, int oflag, mode_t mode);
+int dprintf(int fd, const char *format, ...);
+int vdprintf(int fd, const char *format, va_list ap);
+int vprintf(const char *format, va_list ap);
+int snprintf(char *str, size_t size, const char *format, ...);
+int vsnprintf(char *str, size_t size, const char *format, va_list ap);
+int vfprintf(FILE *f, const char *fmt, va_list ap);
+int fgetc(FILE *stream);
+int getchar(void);
+#define getc(_a) fgetc(_a)
+size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
+size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
+FILE *fopen(const char *pathname, const char *mode);
+int fclose(FILE *stream);
+int fseek(FILE *stream, long offset, int whence);
+int fprintf(FILE *f, const char *fmt, ...);
+long strtol(const char *nptr, char **endptr, int base);
+char *strchr(const char *s, int c);
+char *strcat(char *s1, const char *s2);
+char *fgets(char *s, int n, FILE *stream);
+FILE *tmpfile(void);
+int feof(FILE *stream);
+int fscanf(FILE *stream, const char *format, ...);
+int ungetc(int c, FILE *stream);
+long ftell(FILE *stream);
+int fputc(int c, FILE *stream);
+int remove(const char *path);
+int ferror(FILE *stream);
+int fputs(const char *s, FILE *stream);
+int fflush(FILE *stream);
+#endif
diff --git a/userland/libc/stdio/dprintf.c b/userland/libc/stdio/dprintf.c
new file mode 100644
index 0000000..2f2aadb
--- /dev/null
+++ b/userland/libc/stdio/dprintf.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int dprintf(int fd, const char *format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  int rc = vdprintf(fd, format, ap);
+  va_end(ap);
+  return rc;
+}
diff --git a/userland/libc/stdio/fclose.c b/userland/libc/stdio/fclose.c
new file mode 100644
index 0000000..02d93ae
--- /dev/null
+++ b/userland/libc/stdio/fclose.c
@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fclose.html
+// FIXME: Do some actual error checking.
+int fclose(FILE *stream) {
+    free(stream->cookie);
+    free(stream);
+    return 0;
+}
diff --git a/userland/libc/stdio/feof.c b/userland/libc/stdio/feof.c
new file mode 100644
index 0000000..7f46301
--- /dev/null
+++ b/userland/libc/stdio/feof.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int feof(FILE *stream) {
+    return stream->is_eof;
+}
diff --git a/userland/libc/stdio/ferror.c b/userland/libc/stdio/ferror.c
new file mode 100644
index 0000000..8cb46cf
--- /dev/null
+++ b/userland/libc/stdio/ferror.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int ferror(FILE *stream) {
+    return stream->has_error;
+}
diff --git a/userland/libc/stdio/fflush.c b/userland/libc/stdio/fflush.c
new file mode 100644
index 0000000..7a37c79
--- /dev/null
+++ b/userland/libc/stdio/fflush.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fflush.html
+int fflush(FILE *stream) {
+  // FIXME: Implement
+  return 0;
+}
diff --git a/userland/libc/stdio/fgetc.c b/userland/libc/stdio/fgetc.c
new file mode 100644
index 0000000..c69211f
--- /dev/null
+++ b/userland/libc/stdio/fgetc.c
@@ -0,0 +1,20 @@
+#include <assert.h>
+#include <stdio.h>
+
+int fgetc(FILE *stream) {
+  if (stream->has_buffered_char) {
+    stream->has_buffered_char = 0;
+    return stream->buffered_char;
+  }
+  char c;
+  if (1 == fread(&c, 1, 1, stream))
+    return (int)c;
+  // FIXME: Should use feof and ferror
+  if (stream->has_error)
+    return EOF;
+  if (stream->is_eof)
+    return EOF;
+  // How did we get here?
+  assert(0);
+  return EOF;
+}
diff --git a/userland/libc/stdio/fgetpos.c b/userland/libc/stdio/fgetpos.c
new file mode 100644
index 0000000..7f34d6a
--- /dev/null
+++ b/userland/libc/stdio/fgetpos.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+// FIXME: Error handling
+int fgetpos(FILE *restrict stream, fpos_t *restrict pos) {
+  *pos = (fpos_t)stream->offset_in_file;
+  return 0;
+}
diff --git a/userland/libc/stdio/fgets.c b/userland/libc/stdio/fgets.c
new file mode 100644
index 0000000..8e21501
--- /dev/null
+++ b/userland/libc/stdio/fgets.c
@@ -0,0 +1,16 @@
+#include <stdio.h>
+
+char *fgets(char *s, int n, FILE *stream) {
+  for (int i = 0; i < n; i++) {
+    char c;
+    fread(&c, 1, 1, stream);
+    if (stream->has_error)
+      return NULL;
+    if (stream->is_eof)
+      return NULL;
+    s[i] = c;
+    if (c == '\n')
+      break;
+  }
+  return s;
+}
diff --git a/userland/libc/stdio/fileno.c b/userland/libc/stdio/fileno.c
new file mode 100644
index 0000000..246cc51
--- /dev/null
+++ b/userland/libc/stdio/fileno.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <errno.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fileno.html
+// The fileno() function shall return the integer file descriptor associated
+// with the stream pointed to by stream.
+int fileno(FILE *stream) {
+  if (-1 == stream->fd) {
+    errno = EBADF;
+    return -1;
+  }
+  return stream->fd;
+}
diff --git a/userland/libc/stdio/fopen.c b/userland/libc/stdio/fopen.c
new file mode 100644
index 0000000..a29c7ef
--- /dev/null
+++ b/userland/libc/stdio/fopen.c
@@ -0,0 +1,57 @@
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <stdint.h>
+#include <stdio.h>
+
+// FIXME: All modes not implemented
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fopen.html
+FILE *fopen(const char *pathname, const char *mode) {
+  uint8_t read = 0;
+  uint8_t write = 0;
+  uint8_t append = 0;
+  // FIXME: Not parsed correctly
+  for (; *mode; mode++) {
+    // r or rb
+    // Open file for reading.
+    // w or wb
+    // Truncate to zero length or create file for writing.
+    // a or ab
+    // Append; open or create file for writing at
+    // end-of-file.
+    switch (*mode) {
+    case 'r':
+      read = 1;
+      break;
+    case 'w':
+      write = 1;
+      break;
+    case 'a':
+      append = 1;
+      break;
+    }
+  }
+  int flag = 0;
+  if (read)
+    flag |= O_READ;
+  if (write)
+    flag |= O_WRITE;
+
+  int fd = open(pathname, flag, 0);
+  if (-1 == fd)
+    return NULL;
+
+  struct stat s;
+  stat(pathname, &s);
+
+  FILE *r = malloc(sizeof(FILE));
+  r->read = read_fd;
+  r->write = write_fd;
+  r->seek = seek_fd;
+  r->has_error = 0;
+  r->is_eof = 0;
+  r->offset_in_file = 0;
+  r->file_size = s.st_size;
+  r->cookie = NULL;
+  r->fd = fd;
+  return r;
+}
diff --git a/userland/libc/stdio/fprintf.c b/userland/libc/stdio/fprintf.c
new file mode 100644
index 0000000..f983065
--- /dev/null
+++ b/userland/libc/stdio/fprintf.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int fprintf(FILE *f, const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  int rc = vfprintf(f, fmt, ap);
+  va_end(ap);
+  return rc;
+}
diff --git a/userland/libc/stdio/fputc.c b/userland/libc/stdio/fputc.c
new file mode 100644
index 0000000..7c8fa7c
--- /dev/null
+++ b/userland/libc/stdio/fputc.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int fputc(int c, FILE *stream) {
+  if (fwrite(&c, 1, 1, stream) > 0)
+    return c;
+  return EOF;
+}
diff --git a/userland/libc/stdio/fputs.c b/userland/libc/stdio/fputs.c
new file mode 100644
index 0000000..1b70c66
--- /dev/null
+++ b/userland/libc/stdio/fputs.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int fputs(const char *s, FILE *stream) {
+  const char *b = s;
+  for (; *s; s++)
+    if (0 == fwrite(s, 1, 1, stream))
+      return EOF;
+  return s - b;
+}
diff --git a/userland/libc/stdio/fread.c b/userland/libc/stdio/fread.c
new file mode 100644
index 0000000..1a27afa
--- /dev/null
+++ b/userland/libc/stdio/fread.c
@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <sys/types.h>
+
+size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream) {
+  // FIXME: Check for overflow
+  ssize_t bytes_to_read = nmemb * size;
+  size_t rc = stream->read(stream, ptr, bytes_to_read);
+  // On  success, fread() return the number of items read
+  rc /= size;
+  return rc;
+}
diff --git a/userland/libc/stdio/fscanf.c b/userland/libc/stdio/fscanf.c
new file mode 100644
index 0000000..785ce4b
--- /dev/null
+++ b/userland/libc/stdio/fscanf.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include <assert.h>
+
+int fscanf(FILE *stream, const char *format, ...) {
+    // FIXME
+    assert(0);
+}
diff --git a/userland/libc/stdio/fseek.c b/userland/libc/stdio/fseek.c
new file mode 100644
index 0000000..fb891ec
--- /dev/null
+++ b/userland/libc/stdio/fseek.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <assert.h>
+
+int fseek(FILE *stream, long offset, int whence) {
+    return stream->seek(stream, offset, whence);
+    /*
+  switch (whence) {
+  case SEEK_SET:
+    stream->offset_in_file = offset;
+    break;
+  case SEEK_CUR:
+    stream->offset_in_file += offset;
+    break;
+  case SEEK_END:
+    // FIXME
+    assert(0);
+    break;
+  }
+  // FIXME: Error checking
+  return 0;*/
+}
diff --git a/userland/libc/stdio/fsetpos.c b/userland/libc/stdio/fsetpos.c
new file mode 100644
index 0000000..c39c545
--- /dev/null
+++ b/userland/libc/stdio/fsetpos.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+// FIXME: Error handling
+int fsetpos(FILE *stream, const fpos_t *pos) {
+  stream->offset_in_file = (long)(*pos);
+  return 0;
+}
diff --git a/userland/libc/stdio/ftell.c b/userland/libc/stdio/ftell.c
new file mode 100644
index 0000000..35076d0
--- /dev/null
+++ b/userland/libc/stdio/ftell.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+long ftell(FILE *stream) {
+    return stream->offset_in_file;
+}
diff --git a/userland/libc/stdio/fwrite.c b/userland/libc/stdio/fwrite.c
new file mode 100644
index 0000000..552bbd6
--- /dev/null
+++ b/userland/libc/stdio/fwrite.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <sys/types.h>
+
+size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream) {
+  // FIXME: Check for overflow
+  ssize_t bytes_to_write = nmemb * size;
+  size_t rc = stream->write(stream, ptr, bytes_to_write);
+  // On  success, fwrite() return the number of items
+  // written.
+  rc /= size;
+  return rc;
+}
diff --git a/userland/libc/stdio/getchar.c b/userland/libc/stdio/getchar.c
new file mode 100644
index 0000000..dad2263
--- /dev/null
+++ b/userland/libc/stdio/getchar.c
@@ -0,0 +1,4 @@
+#include <stdio.h>
+
+// The getchar() function shall be equivalent to getc(stdin).
+int getchar(void) { return fgetc(stdin); }
diff --git a/userland/libc/stdio/open_memstream.c b/userland/libc/stdio/open_memstream.c
new file mode 100644
index 0000000..8f359b9
--- /dev/null
+++ b/userland/libc/stdio/open_memstream.c
@@ -0,0 +1,108 @@
+#include <assert.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+/*
+struct __IO_FILE {
+  size_t (*write)(FILE *, const unsigned char *, size_t);
+  size_t (*read)(FILE *, unsigned char *, size_t);
+  int (*seek)(FILE *, long, int);
+  long offset_in_file;
+  int buffered_char;
+  int has_buffered_char;
+  int fd;
+  uint8_t is_eof;
+  uint8_t has_error;
+  uint64_t file_size;
+  void *cookie;
+};
+*/
+
+struct Memstream {
+  size_t buffer_usage;
+  char *buffer;
+};
+
+#define MEMSTREAM_DEF_SIZE 4096
+
+size_t memstream_write(FILE *fp, const unsigned char *buf, size_t n) {
+  struct Memstream *c = fp->cookie;
+  // FIXME: Do a reallocation
+  if (c->buffer_usage + n >= fp->file_size) {
+    n = fp->file_size - c->buffer_usage;
+  }
+
+  memcpy(c->buffer + fp->offset_in_file, buf, n);
+  fp->offset_in_file += n;
+  if (fp->offset_in_file > c->buffer_usage)
+    c->buffer_usage = fp->offset_in_file;
+  return n;
+}
+
+size_t memstream_read(FILE *fp, unsigned char *buf, size_t n) {
+  struct Memstream *c = fp->cookie;
+  size_t length_left = c->buffer_usage - fp->offset_in_file;
+  n = min(length_left, n);
+  memcpy(buf, c->buffer + fp->offset_in_file, n);
+  fp->offset_in_file += n;
+  if (0 == n)
+    fp->is_eof = 1;
+  return n;
+}
+
+int memstream_seek(FILE *stream, long offset, int whence) {
+  switch (whence) {
+  case SEEK_SET:
+    stream->offset_in_file = offset;
+    break;
+  case SEEK_CUR:
+    stream->offset_in_file += offset;
+    break;
+  case SEEK_END:
+    stream->offset_in_file = stream->file_size + offset;
+    break;
+  default:
+    assert(0);
+    break;
+  }
+  // FIXME: Error checking
+  return 0;
+}
+
+FILE *open_memstream(char **bufp, size_t *sizep) {
+  struct Memstream *c = NULL;
+  FILE *fp = malloc(sizeof(FILE));
+  if (!fp)
+    return NULL;
+
+  fp->offset_in_file = 0;
+  fp->buffered_char = 0;
+  fp->has_buffered_char = 0;
+  fp->seek = memstream_seek;
+  fp->fd = -1;
+  fp->is_eof = 0;
+  fp->has_error = 0;
+  fp->file_size = MEMSTREAM_DEF_SIZE;
+
+  fp->write = memstream_write;
+  fp->read = memstream_read;
+
+  c = malloc(sizeof(struct Memstream));
+  if (!c) {
+    goto _exit_memstream_fail;
+  }
+
+  fp->cookie = (void *)c;
+
+  c->buffer = *bufp = malloc(MEMSTREAM_DEF_SIZE);
+  if (!bufp) {
+    goto _exit_memstream_fail;
+  }
+  c->buffer_usage = 0;
+
+  return fp;
+_exit_memstream_fail:
+  free(c);
+  free(fp);
+  return NULL;
+}
diff --git a/userland/libc/stdio/printf.c b/userland/libc/stdio/printf.c
new file mode 100644
index 0000000..d26568a
--- /dev/null
+++ b/userland/libc/stdio/printf.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int printf(const char *format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  int rc = vprintf(format, ap);
+  va_end(ap);
+  return rc;
+}
diff --git a/userland/libc/stdio/putc.c b/userland/libc/stdio/putc.c
new file mode 100644
index 0000000..a468a95
--- /dev/null
+++ b/userland/libc/stdio/putc.c
@@ -0,0 +1,3 @@
+#include <stdio.h>
+
+int putc(int c, FILE *stream) { return fputc(c, stream);}
diff --git a/userland/libc/stdio/putchar.c b/userland/libc/stdio/putchar.c
new file mode 100644
index 0000000..3fcf7ca
--- /dev/null
+++ b/userland/libc/stdio/putchar.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int putchar(int c) {
+  printf("%c", (char)c);
+  return c;
+}
diff --git a/userland/libc/stdio/puts.c b/userland/libc/stdio/puts.c
new file mode 100644
index 0000000..4a72e66
--- /dev/null
+++ b/userland/libc/stdio/puts.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int puts(const char *s) {
+  int rc = printf("%s\n", s);
+  return rc;
+}
diff --git a/userland/libc/stdio/remove.c b/userland/libc/stdio/remove.c
new file mode 100644
index 0000000..35b41ad
--- /dev/null
+++ b/userland/libc/stdio/remove.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+#include <errno.h>
+
+extern int errno;
+int remove(const char *path) {
+  // FIXME
+  errno = ENAMETOOLONG;
+  return -1;
+}
diff --git a/userland/libc/stdio/rename.c b/userland/libc/stdio/rename.c
new file mode 100644
index 0000000..15d4bf5
--- /dev/null
+++ b/userland/libc/stdio/rename.c
@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <assert.h>
+
+int rename(const char *old, const char *new) {
+	(void)old;
+	(void)new;
+  assert(0); // TODO: Implement
+	     }
diff --git a/userland/libc/stdio/setvbuf.c b/userland/libc/stdio/setvbuf.c
new file mode 100644
index 0000000..7f91518
--- /dev/null
+++ b/userland/libc/stdio/setvbuf.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int setvbuf(FILE *restrict stream, char *restrict buf, int type, size_t size) {
+  // TODO
+  return 0;
+}
diff --git a/userland/libc/stdio/snprintf.c b/userland/libc/stdio/snprintf.c
new file mode 100644
index 0000000..328442a
--- /dev/null
+++ b/userland/libc/stdio/snprintf.c
@@ -0,0 +1,42 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+struct sn_cookie {
+  char *s;
+  size_t n;
+};
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+size_t sn_write(FILE *f, const unsigned char *s, const size_t l) {
+  struct sn_cookie *c = f->cookie;
+  size_t k = MIN(l, c->n);
+  memcpy(c->s, s, k);
+  c->s += k;
+  c->n -= k;
+  *(c->s) = '\0';
+  // Upon successful completion, the snprintf() function shall return the number
+  // of bytes that would be written to s had n been sufficiently large excluding
+  // the terminating null byte.
+  return l;
+}
+
+int vsnprintf(char *str, size_t size, const char *format, va_list ap) {
+  char dummy[1];
+  struct sn_cookie c = {.s = (size ? str : dummy), .n = (size ? size - 1 : 0)};
+  FILE f = {
+      .write = sn_write,
+      .cookie = &c,
+  };
+  return vfprintf(&f, format, ap);
+}
+
+int snprintf(char *str, size_t size, const char *format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  int rc = vsnprintf(str, size, format, ap);
+  va_end(ap);
+  return rc;
+}
diff --git a/userland/libc/stdio/sprintf.c b/userland/libc/stdio/sprintf.c
new file mode 100644
index 0000000..deffbbe
--- /dev/null
+++ b/userland/libc/stdio/sprintf.c
@@ -0,0 +1,33 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+struct s_cookie {
+  char *s;
+};
+
+size_t s_write(FILE *f, const unsigned char *s, size_t l) {
+  struct s_cookie *c = f->cookie;
+  memcpy(c->s, s, l);
+  c->s += l;
+  *(c->s) = '\0';
+  return l;
+}
+
+int vsprintf(char *str, const char *format, va_list ap) {
+  struct s_cookie c = {.s = str};
+  FILE f = {
+      .write = s_write,
+      .cookie = &c,
+  };
+  return vfprintf(&f, format, ap);
+}
+
+int sprintf(char *str, const char *format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  int rc = vsprintf(str, format, ap);
+  va_end(ap);
+  return rc;
+}
diff --git a/userland/libc/stdio/stderr.c b/userland/libc/stdio/stderr.c
new file mode 100644
index 0000000..76597e2
--- /dev/null
+++ b/userland/libc/stdio/stderr.c
@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <unistd.h>
+
+FILE __stderr_FILE = {
+    .write = write_fd,
+    .read = read_fd,
+    .is_eof = 0,
+    .has_error = 0,
+    .cookie = NULL,
+    .fd = 2,
+};
diff --git a/userland/libc/stdio/stdin.c b/userland/libc/stdio/stdin.c
new file mode 100644
index 0000000..ae3ab8d
--- /dev/null
+++ b/userland/libc/stdio/stdin.c
@@ -0,0 +1,54 @@
+#include <assert.h>
+#include <stdio.h>
+#include <unistd.h>
+
+size_t write_fd(FILE *f, const unsigned char *s, size_t l) {
+  int rc = pwrite(f->fd, s, l, f->offset_in_file);
+  if (rc == -1) {
+    f->has_error = 1;
+    return 0;
+  }
+  f->offset_in_file += rc;
+  return rc;
+}
+
+size_t read_fd(FILE *f, unsigned char *s, size_t l) {
+  int rc = pread(f->fd, s, l, f->offset_in_file);
+  if (rc == 0)
+    f->is_eof = 1;
+  if (rc == -1) {
+    f->has_error = 1;
+    return 0;
+  }
+  f->offset_in_file += rc;
+  return rc;
+}
+
+int seek_fd(FILE *stream, long offset, int whence) {
+  switch (whence) {
+  case SEEK_SET:
+    stream->offset_in_file = offset;
+    break;
+  case SEEK_CUR:
+    stream->offset_in_file += offset;
+    break;
+  case SEEK_END:
+    stream->offset_in_file = stream->file_size + offset;
+    break;
+  default:
+    assert(0);
+    break;
+  }
+  // FIXME: Error checking
+  return 0;
+}
+
+FILE __stdin_FILE = {
+    .write = write_fd,
+    .read = read_fd,
+    .seek = NULL,
+    .is_eof = 0,
+    .has_error = 0,
+    .cookie = NULL,
+    .fd = 0,
+};
diff --git a/userland/libc/stdio/stdout.c b/userland/libc/stdio/stdout.c
new file mode 100644
index 0000000..7f4edf0
--- /dev/null
+++ b/userland/libc/stdio/stdout.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <unistd.h>
+
+FILE __stdout_FILE = {
+    .write = write_fd,
+    .read = read_fd,
+    .is_eof = 0,
+    .has_error = 0,
+    .seek = NULL,
+    .cookie = NULL,
+    .fd = 1,
+};
+FILE __stderr_FILE;
diff --git a/userland/libc/stdio/tmpfile.c b/userland/libc/stdio/tmpfile.c
new file mode 100644
index 0000000..cee6e0a
--- /dev/null
+++ b/userland/libc/stdio/tmpfile.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+#include <assert.h>
+
+FILE *tmpfile(void) {
+    // TODO
+    printf("TODO: Implement tmpfile()\n");
+    assert(0);
+    return NULL;
+}
diff --git a/userland/libc/stdio/tmpnam.c b/userland/libc/stdio/tmpnam.c
new file mode 100644
index 0000000..aafe67d
--- /dev/null
+++ b/userland/libc/stdio/tmpnam.c
@@ -0,0 +1,10 @@
+#include <assert.h>
+#include <stdio.h>
+
+char *tmpnam(char *s) {
+  assert(!s);
+  s = malloc(100);
+  strcpy(s, "/tmp.XXXXXX");
+  mkstemp(s);
+  return s;
+}
diff --git a/userland/libc/stdio/ungetc.c b/userland/libc/stdio/ungetc.c
new file mode 100644
index 0000000..8d649bc
--- /dev/null
+++ b/userland/libc/stdio/ungetc.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int ungetc(int c, FILE *stream) {
+  if (stream->has_buffered_char)
+    return EOF;
+  stream->buffered_char = c;
+  stream->has_buffered_char = 1;
+  return c;
+}
diff --git a/userland/libc/stdio/vdprintf.c b/userland/libc/stdio/vdprintf.c
new file mode 100644
index 0000000..b3fa065
--- /dev/null
+++ b/userland/libc/stdio/vdprintf.c
@@ -0,0 +1,77 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+struct vd_cookie {
+  int fd;
+  char *buffer;
+  uint8_t buf_len;
+  uint8_t buf_used;
+  int sent_bytes;
+};
+
+size_t min(size_t a, size_t b) { return (a < b) ? a : b; }
+
+size_t vd_write(FILE *f, const unsigned char *s, size_t l) {
+  struct vd_cookie *c = f->cookie;
+
+  int clear_buffer = 0;
+  size_t b_copy = min(l, c->buf_len - (c->buf_used));
+  for (int i = 0; i < b_copy; i++) {
+    c->buffer[c->buf_used + i] = s[i];
+    if (s[i] == '\n')
+      clear_buffer = 1;
+  }
+  c->buf_used += b_copy;
+
+  if (clear_buffer) {
+    int rc = write(c->fd, c->buffer, c->buf_used);
+    c->buf_used = 0;
+    if (-1 == rc) {
+      return (size_t)-1;
+    }
+    c->sent_bytes += rc;
+  }
+  return l;
+}
+
+int vdprintf(int fd, const char *format, va_list ap) {
+  FILE f = {
+      .write = write_fd,
+      .fd = fd,
+  };
+  return vfprintf(&f, format, ap);
+  //    return -1;
+  /*
+char buffer[32];
+struct vd_cookie c = {.fd = fd,
+                  .buffer = buffer,
+                  .buf_len = 32,
+                  .buf_used = 0,
+                  .sent_bytes = 0};
+FILE f = {
+.write = vd_write,
+.cookie = &c,
+};
+
+// If an output error was encountered, these functions shall return a
+// negative value and set errno to indicate the error.
+if (-1 == vfprintf(&f, format, ap))
+return -1;
+
+// Upon successful completion, the dprintf(),
+// fprintf(), and printf() functions shall return the number of bytes
+// transmitted.
+
+if(0 == c.buf_used)
+return c.sent_bytes;
+
+// First the current buffer needs to be cleared
+int rc = write(fd, buffer, c.buf_used);
+if (-1 == rc) {
+return -1;
+}
+c.sent_bytes += rc;
+return c.sent_bytes;*/
+}
diff --git a/userland/libc/stdio/vfprintf.c b/userland/libc/stdio/vfprintf.c
new file mode 100644
index 0000000..79a22fb
--- /dev/null
+++ b/userland/libc/stdio/vfprintf.c
@@ -0,0 +1,243 @@
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+const char HEX_SET[0x10] = {'0', '1', '2', '3', '4', '5', '6', '7',
+                            '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+
+#define FILE_WRITE(_f, _s, _l, _r)                                             \
+  {                                                                            \
+    size_t _rc = _f->write(_f, (const unsigned char *)_s, _l);                 \
+    if ((size_t)-1 == _rc)                                                     \
+      assert(0);                                                               \
+    *(int *)(_r) += _rc;                                                       \
+  }
+//    if ((size_t)0 == _rc)                                                      \
+//      assert(0);                                                               \
+
+int fprint_num(FILE *f, int n, int base, char *char_set, int prefix,
+               int zero_padding, int right_padding) {
+  int c = 0;
+  if (0 == n) {
+    zero_padding = 1;
+    prefix = 1;
+  }
+  char str[32];
+  int i = 0;
+  for (; n != 0 && i < 32; i++, n /= base)
+    //    str[i] = (n % base) + '0';
+    str[i] = char_set[(n % base)];
+
+  char t = (zero_padding) ? '0' : ' ';
+  int orig_i = i;
+
+  if (!right_padding) {
+    for (; prefix - orig_i > 0; prefix--)
+      FILE_WRITE(f, &t, 1, &c);
+  }
+
+  for (i--; i >= 0; i--)
+    FILE_WRITE(f, &(str[i]), 1, &c);
+
+  if (right_padding) {
+    for (; prefix - orig_i > 0; prefix--)
+      FILE_WRITE(f, &t, 1, &c);
+  }
+  return c;
+}
+
+int fprint_int(FILE *f, int n, int prefix, int zero_padding,
+               int right_padding) {
+  return fprint_num(f, n, 10, "0123456789", prefix, zero_padding,
+                    right_padding);
+}
+
+int fprint_hex(FILE *f, int n, int prefix, int zero_padding,
+               int right_padding) {
+  return fprint_num(f, n, 16, "0123456789abcdef", prefix, zero_padding,
+                    right_padding);
+}
+
+int fprint_octal(FILE *f, int n, int prefix, int zero_padding,
+                 int right_padding) {
+  return fprint_num(f, n, 8, "012345678", prefix, zero_padding, right_padding);
+}
+
+int print_string(FILE *f, const char *s, int *rc, int prefix, int right_padding,
+                 int precision) {
+  int l = strlen(s);
+  char t = ' ';
+  int c = 0;
+  if (!right_padding) {
+    if (prefix)
+      assert(-1 == precision); // FIXME: Is this correct?
+    for (; prefix - l > 0; prefix--)
+      FILE_WRITE(f, &t, 1, &c);
+  }
+  int bl = precision;
+  for (; *s; s++, (*rc)++) {
+    if (precision != -1) {
+      if (0 == bl)
+        break;
+      bl--;
+    }
+    int r;
+    FILE_WRITE(f, (const unsigned char *)s, 1, &r);
+    assert(r != 0);
+  }
+  if (right_padding) {
+    assert(-1 == precision); // FIXME: Is this correct?
+    for (; prefix - l > 0; prefix--)
+      FILE_WRITE(f, &t, 1, &c);
+  }
+  (*rc) += c;
+  return 0;
+}
+
+int parse_precision(const char **fmt) {
+  const char *s = *fmt;
+  int rc = 0;
+  for (int i = 0;; i++, s++) {
+    if ('\0' == *s)
+      break;
+    const char c = *s;
+    if ('*' == c) {
+      assert(i == 0);
+      return -1;
+    } else if (!(c >= '0' && c <= '9')) {
+      s--;
+      break;
+    }
+    rc *= 10;
+    rc += c - '0';
+  }
+  *fmt = s;
+  return rc;
+}
+
+int vfprintf(FILE *f, const char *fmt, va_list ap) {
+  int rc = 0;
+  const char *s = fmt;
+  int prefix = 0;
+
+  int zero_padding = 0;
+  int right_padding = 0;
+
+  int cont = 0;
+  int precision = -1;
+  for (; *s; s++) {
+    if (!cont && '%' != *s) {
+      FILE_WRITE(f, (const unsigned char *)s, 1, &rc);
+      continue;
+    }
+    if (!cont) {
+      cont = 1;
+      continue;
+    }
+
+    if ('\0' == *s)
+      break;
+
+    switch (*s) {
+    case '.':
+      s++;
+      assert('\0' != *s);
+      precision = parse_precision(&s);
+      assert('\0' != *s);
+      if (-1 == precision)
+        precision = va_arg(ap, int);
+      cont = 1;
+      break;
+    case '0':
+      prefix *= 10;
+      if (0 == prefix)
+        zero_padding = 1;
+      cont = 1;
+      break;
+    case '-':
+      assert(0 == prefix);
+      right_padding = 1;
+      cont = 1;
+      break;
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9':
+      prefix *= 10;
+      prefix += (*s) - '0';
+      cont = 1;
+      break;
+    case 'i':
+    case 'd':
+      if(-1 != precision) {
+      zero_padding = 1;
+      prefix = precision;
+      right_padding = 0;
+      }
+      rc += fprint_int(f, va_arg(ap, int), prefix, zero_padding, right_padding);
+      cont = 0;
+      break;
+    case 'u':
+      assert(-1 == precision);
+      rc += fprint_int(f, va_arg(ap, unsigned int), prefix, zero_padding,
+                       right_padding);
+      cont = 0;
+      break;
+    case 's': {
+      assert(!zero_padding); // this is not supported to strings
+      char *a = va_arg(ap, char *);
+      if (!a) {
+        if (-1 ==
+            print_string(f, "(NULL)", &rc, prefix, right_padding, precision))
+          return -1;
+        cont = 0;
+        break;
+      }
+      if (-1 == print_string(f, a, &rc, prefix, right_padding, precision))
+        return -1;
+      cont = 0;
+      break;
+    }
+    case 'p': // TODO: Print this out in a nicer way
+    case 'x':
+      assert(-1 == precision);
+      rc += fprint_hex(f, va_arg(ap, const uint32_t), prefix, zero_padding,
+                       right_padding);
+      cont = 0;
+      break;
+    case 'o':
+      assert(-1 == precision);
+      rc += fprint_octal(f, va_arg(ap, const uint32_t), prefix, zero_padding,
+                         right_padding);
+      cont = 0;
+      break;
+    case '%': {
+      FILE_WRITE(f, (const unsigned char *)"%", 1, &rc);
+      cont = 0;
+      break;
+    }
+    case 'c': {
+      char c = va_arg(ap, const int);
+      FILE_WRITE(f, (const unsigned char *)&c, 1, &rc);
+      cont = 0;
+      break;
+    }
+    default:
+      printf("got %c but that is not supported by printf\n", *s);
+      assert(0);
+      break;
+    }
+    if (!cont) {
+      prefix = 0;
+      zero_padding = right_padding = 0;
+      precision = -1;
+    }
+  }
+  return rc;
+}
diff --git a/userland/libc/stdio/vprintf.c b/userland/libc/stdio/vprintf.c
new file mode 100644
index 0000000..8a8dc33
--- /dev/null
+++ b/userland/libc/stdio/vprintf.c
@@ -0,0 +1,3 @@
+#include <stdio.h>
+
+int vprintf(const char *format, va_list ap) { return vdprintf(1, format, ap); }
diff --git a/userland/libc/stdlib.h b/userland/libc/stdlib.h
new file mode 100644
index 0000000..bba5d84
--- /dev/null
+++ b/userland/libc/stdlib.h
@@ -0,0 +1,17 @@
+#ifndef STDLIB_H
+#define STDLIB_H
+#include <stddef.h>
+#include <limits.h>
+#define RAND_MAX (UINT32_MAX)
+
+void *malloc(size_t s);
+void *calloc(size_t nelem, size_t elsize);
+void *realloc(void *ptr, size_t size);
+void free(void *p);
+char *getenv(const char *name);
+int rand(void);
+void srand(unsigned int seed);
+unsigned long strtoul(const char *restrict str,
+       char **restrict endptr, int base);
+int atoi(const char *str);
+#endif
diff --git a/userland/libc/stdlib/abort.c b/userland/libc/stdlib/abort.c
new file mode 100644
index 0000000..7fd747e
--- /dev/null
+++ b/userland/libc/stdlib/abort.c
@@ -0,0 +1,10 @@
+#include <assert.h>
+#include <stdlib.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/abort.html
+void abort(void) {
+  printf("aborting!!!!\n");
+  assert(0);
+  for (;;)
+    ;
+}
diff --git a/userland/libc/stdlib/abs.c b/userland/libc/stdlib/abs.c
new file mode 100644
index 0000000..1079beb
--- /dev/null
+++ b/userland/libc/stdlib/abs.c
@@ -0,0 +1,3 @@
+#include <stdlib.h>
+
+int abs(int i) { return (i < 0) ? (-i) : (i); }
diff --git a/userland/libc/stdlib/atexit.c b/userland/libc/stdlib/atexit.c
new file mode 100644
index 0000000..0e401ff
--- /dev/null
+++ b/userland/libc/stdlib/atexit.c
@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+int atexit(void (*func)(void)) {
+	//TODO
+	return 0;
+}
diff --git a/userland/libc/stdlib/atof.c b/userland/libc/stdlib/atof.c
new file mode 100644
index 0000000..8524f8b
--- /dev/null
+++ b/userland/libc/stdlib/atof.c
@@ -0,0 +1,5 @@
+#include <stdlib.h>
+
+double atof(const char *str) {
+	return strtod(str,(char **)NULL);
+}
diff --git a/userland/libc/stdlib/atoi.c b/userland/libc/stdlib/atoi.c
new file mode 100644
index 0000000..2183306
--- /dev/null
+++ b/userland/libc/stdlib/atoi.c
@@ -0,0 +1,4 @@
+#include <stdlib.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+int atoi(const char *str) { return (int)strtol(str, (char **)NULL, 10); }
diff --git a/userland/libc/stdlib/getenv.c b/userland/libc/stdlib/getenv.c
new file mode 100644
index 0000000..9a6a4e5
--- /dev/null
+++ b/userland/libc/stdlib/getenv.c
@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+char *getenv(const char *name) {
+    // FIXME
+    return NULL;
+}
diff --git a/userland/libc/stdlib/mkstemp.c b/userland/libc/stdlib/mkstemp.c
new file mode 100644
index 0000000..1ea8790
--- /dev/null
+++ b/userland/libc/stdlib/mkstemp.c
@@ -0,0 +1,14 @@
+#include <fcntl.h>
+#include <stdlib.h>
+
+char rand_char(void) { return 'A' + (rand() % 10); }
+
+int mkstemp(char *template) {
+  // FIXME: Incomplete
+  const char *s = template;
+  for (; *template; template ++) {
+    if ('X' == *template)
+      *template = rand_char();
+  }
+  return open(s, O_RDWR, O_CREAT);
+}
diff --git a/userland/libc/stdlib/qsort.c b/userland/libc/stdlib/qsort.c
new file mode 100644
index 0000000..3f87db5
--- /dev/null
+++ b/userland/libc/stdlib/qsort.c
@@ -0,0 +1,29 @@
+#include <stdlib.h>
+#include <string.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/qsort.html
+void qsort(void *base, size_t nel, size_t width,
+           int (*compar)(const void *, const void *)) {
+  // If the nel argument has the value zero, the comparison function pointed to
+  // by compar shall not be called and no rearrangement shall take place.
+  if (0 == nel)
+    return;
+  
+  // AB
+  // Results in negative
+  // BA
+  // Results in positive
+
+  // Using bubblesort
+  unsigned char *p = base;
+  for (size_t i = 1; i < nel; i++) {
+    for (size_t j = 0; j < nel; j++) {
+      if (compar((p + i * width), (p + j * width)) < 0) {
+        unsigned char tmp[width];
+        memcpy(tmp, (p + i * width), width);
+        memcpy((p + i * width), (p + j * width), width);
+        memcpy((p + j * width), tmp, width);
+      }
+    }
+  }
+}
diff --git a/userland/libc/stdlib/rand.c b/userland/libc/stdlib/rand.c
new file mode 100644
index 0000000..e186af7
--- /dev/null
+++ b/userland/libc/stdlib/rand.c
@@ -0,0 +1,17 @@
+#include <stdint.h>
+#include <stdlib.h>
+
+uint32_t xorshift(uint32_t x) {
+  uint32_t f = x;
+  x ^= x << 13;
+  x ^= x >> 17;
+  x ^= x << 5;
+  return f + x;
+}
+
+extern uint32_t __INTERNAL_RNG_STATE;
+int rand(void) {
+  uint32_t x = xorshift(__INTERNAL_RNG_STATE);
+  __INTERNAL_RNG_STATE++;
+  return x;
+}
diff --git a/userland/libc/stdlib/srand.c b/userland/libc/stdlib/srand.c
new file mode 100644
index 0000000..a35185a
--- /dev/null
+++ b/userland/libc/stdlib/srand.c
@@ -0,0 +1,8 @@
+#include <stdint.h>
+#include <stdlib.h>
+
+uint32_t __INTERNAL_RNG_STATE;
+void srand(unsigned int seed) {
+  __INTERNAL_RNG_STATE = seed;
+  __INTERNAL_RNG_STATE = rand(); // rand() used the internal rng state
+}
diff --git a/userland/libc/stdlib/strtod.c b/userland/libc/stdlib/strtod.c
new file mode 100644
index 0000000..2c83879
--- /dev/null
+++ b/userland/libc/stdlib/strtod.c
@@ -0,0 +1,70 @@
+#include <ctype.h>
+#include <stdlib.h>
+#include <assert.h>
+
+int ctoi(char c) { return c - '0'; }
+
+double strtod(const char *restrict nptr, char **restrict endptr) {
+  double r = 0;
+  // An initial, possibly empty, sequence of white-space characters (as
+  // specified by isspace())
+  for (; isspace(*nptr); nptr++)
+    ;
+
+  // A subject sequence interpreted as a floating-point constant or representing
+  // infinity or NaN
+
+  {
+    // The expected form of the subject sequence is an optional '+' or '-' sign
+    int sign = 0;
+    int exp_sign = 0;
+    if ('+' == *nptr) {
+      sign = 0;
+      nptr++;
+    } else if ('-' == *nptr) {
+      sign = 1;
+      nptr++;
+    }
+
+    // A non-empty sequence of decimal digits optionally containing a radix
+    // character
+    double exp = 0;
+    for (; isdigit(*nptr); nptr++) {
+      r *= 10;
+      r += ctoi(*nptr);
+    }
+    if ('.' == *nptr) {
+      double div = 10;
+      for (; isdigit(*nptr); nptr++) {
+        r += ctoi(*nptr) / div;
+        div *= 10;
+      }
+    }
+    r *= (sign) ? (-1) : (1);
+
+    // then an optional exponent part consisting of the character 'e' or
+    // the character 'E'
+    if ('e' == tolower(*nptr)) {
+      // optionally followed by a '+' or '-' character
+      if ('+' == *nptr) {
+        exp_sign = 0;
+        nptr++;
+      } else if ('-' == *nptr) {
+        exp_sign = 1;
+        nptr++;
+      }
+      // and then followed by one or more decimal digits
+      for (; isdigit(*nptr); nptr++) {
+        exp *= 10;
+        exp += ctoi(*nptr);
+      }
+      exp *= (exp_sign) ? (-1) : (1);
+    }
+    assert(0 == exp); // TODO
+  }
+
+  // A final string of one or more unrecognized characters, including the
+  // terminating NUL character of the input string
+  ;
+  return r;
+}
diff --git a/userland/libc/stdlib/strtol.c b/userland/libc/stdlib/strtol.c
new file mode 100644
index 0000000..7aa7760
--- /dev/null
+++ b/userland/libc/stdlib/strtol.c
@@ -0,0 +1,52 @@
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <assert.h>
+
+extern int errno;
+extern int get_value(char c, long base);
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtol.html
+long strtol(const char *str, char **restrict endptr, int base) {
+  long ret_value = 0;
+  if (endptr)
+    *endptr = str;
+  // Ignore inital white-space sequence
+  for (; *str && isspace(*str); str++)
+    ;
+  if (!*str)
+    return ret_value;
+
+  int sign = 0;
+  if ('-' == *str) {
+    // FIXME
+    sign = 1;
+    str++;
+    assert(0);
+  } else if ('+' == *str) {
+    str++;
+  }
+
+  if (0 == base) {
+    // FIXME
+    assert(0);
+  }
+
+  if (2 <= base && 36 >= base) {
+    for (; *str; str++) {
+      ret_value *= base;
+      int val = get_value(*str, base);
+      if (ret_value > LONG_MAX - val) {
+        errno = ERANGE;
+        return 0;
+      }
+      ret_value += val;
+    }
+  } else {
+    errno = EINVAL;
+    return 0;
+  }
+  if (endptr)
+    *endptr = str;
+  return ret_value;
+}
diff --git a/userland/libc/stdlib/strtold.c b/userland/libc/stdlib/strtold.c
new file mode 100644
index 0000000..222464e
--- /dev/null
+++ b/userland/libc/stdlib/strtold.c
@@ -0,0 +1,9 @@
+#include <assert.h>
+#include <stdlib.h>
+
+long double strtold(const char *restrict nptr, char **restrict endptr) {
+  // TODO
+  // I will do this some other day
+  assert(NULL);
+  return 0;
+}
diff --git a/userland/libc/stdlib/strtoul.c b/userland/libc/stdlib/strtoul.c
new file mode 100644
index 0000000..4d9a51d
--- /dev/null
+++ b/userland/libc/stdlib/strtoul.c
@@ -0,0 +1,72 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <limits.h>
+
+extern int errno;
+int get_value(char c, long base) {
+  int r;
+  if (c >= '0' && c <= '9')
+    r = c - '0';
+  else if (c >= 'A' && c <= 'Z')
+    r = c - 'A';
+  else if (c >= 'a' && c <= 'z')
+    r = c - 'a';
+  else
+    return -1;
+  if (r >= base)
+    return -1;
+  return r;
+}
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtoul.html
+unsigned long strtoul(const char *restrict str, char **restrict endptr,
+                      int base) {
+  unsigned long ret_value = 0;
+  if (endptr)
+    *endptr = str;
+  // Ignore inital white-space sequence
+  for (; *str && isspace(*str); str++)
+    ;
+  if (!*str)
+    return ret_value;
+
+  int sign = 0;
+  if ('-' == *str) {
+    // FIXME
+    sign = 1;
+    str++;
+    assert(0);
+  } else if ('+' == *str) {
+    str++;
+  }
+
+  if (0 == base) {
+    // FIXME
+    assert(0);
+  }
+
+  if (2 <= base && 36 >= base) {
+    for (; *str; str++) {
+      ret_value *= base;
+      int val = get_value(*str, base);
+      /*
+      if (-1 == val) {
+        errno = ERANGE;
+        return 0;
+      }*/
+      if (ret_value > ULONG_MAX - val) {
+        errno = ERANGE;
+        return 0;
+      }
+
+      ret_value += val;
+    }
+  } else {
+    errno = EINVAL;
+    return 0;
+  }
+  if (endptr)
+    *endptr = str;
+  return ret_value;
+}
diff --git a/userland/libc/stdlib/system.c b/userland/libc/stdlib/system.c
new file mode 100644
index 0000000..d951c5c
--- /dev/null
+++ b/userland/libc/stdlib/system.c
@@ -0,0 +1,17 @@
+#include <stdlib.h>
+
+int system(const char *command) {
+  if (!command)
+    return NULL;
+  int pid = fork();
+  if (0 == pid) {
+    char *argv[2];
+    argv[0] = "/sh";
+    argv[1] = command;
+    execv("/sh", argv);
+  }
+  // FIXME: Use waitpid
+  int rc;
+  (void)wait(&rc);
+  return rc;
+}
diff --git a/userland/libc/string.h b/userland/libc/string.h
new file mode 100644
index 0000000..f811dba
--- /dev/null
+++ b/userland/libc/string.h
@@ -0,0 +1,17 @@
+#ifndef STRING_H
+#define STRING_H
+#include <stddef.h>
+#include <stdint.h>
+
+char *strerror(int errnum);
+void *memset(void *s, int c, size_t n);
+void *memcpy(void *dest, const void *src, uint32_t n);
+int strcmp(const char *s1, const char *s2);
+char *strcpy(char *dest, const char *src);
+size_t strlen(const char *s);
+size_t strnlen(const char *s, size_t maxlen);
+int sscanf(const char *s, const char *restrict format, ...);
+char *strrchr(const char *s, int c);
+int strncmp(const char *s1, const char *s2, size_t n);
+char *strncpy(char *s1, const char *s2, size_t n);
+#endif
diff --git a/userland/libc/string/memcmp.c b/userland/libc/string/memcmp.c
new file mode 100644
index 0000000..01109b8
--- /dev/null
+++ b/userland/libc/string/memcmp.c
@@ -0,0 +1,11 @@
+#include <string.h>
+
+int memcmp(const void *s1, const void *s2, size_t n) {
+  int return_value = 0;
+
+  for (uint32_t i = 0; i < n; i++)
+    if (((unsigned char *)(s1))[i] != ((unsigned char *)(s2))[i])
+      return_value++;
+
+  return return_value;
+}
diff --git a/userland/libc/string/memcpy.c b/userland/libc/string/memcpy.c
new file mode 100644
index 0000000..e19dec9
--- /dev/null
+++ b/userland/libc/string/memcpy.c
@@ -0,0 +1,9 @@
+#include <string.h>
+
+void *memcpy(void *dest, const void *src, uint32_t n) {
+  unsigned char *d = dest;
+  const unsigned char *s = src;
+  for (; n; n--)
+    *d++ = *s++;
+  return dest;
+}
diff --git a/userland/libc/string/memmove.c b/userland/libc/string/memmove.c
new file mode 100644
index 0000000..5fc49f7
--- /dev/null
+++ b/userland/libc/string/memmove.c
@@ -0,0 +1,14 @@
+#include <string.h>
+
+// copy bytes in memory with overlapping areas
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/memmove.html
+void *memmove(void *s1, const void *s2, size_t n) {
+  // Copying takes place as if the n bytes from the object pointed to by s2 are
+  // first copied into a temporary array of n bytes that does not overlap the
+  // objects pointed to by s1 and s2, and then the n bytes from the temporary
+  // array are copied into the object pointed to by s1.
+  unsigned char tmp[n];
+  memcpy(tmp, s2, n);
+  memcpy(s1, tmp, n);
+  return s1;
+}
diff --git a/userland/libc/string/sscanf.c b/userland/libc/string/sscanf.c
new file mode 100644
index 0000000..28e1ce1
--- /dev/null
+++ b/userland/libc/string/sscanf.c
@@ -0,0 +1,193 @@
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+extern int errno;
+extern int get_value(char c, long base);
+
+long ftnum(FILE *stream, int base, int *error) {
+  char c;
+  long ret_value = 0;
+  *error = 0;
+  // Ignore inital white-space sequence
+  for (;;) {
+    if (EOF == (c = fgetc(stream))) {
+      *error = 1;
+      return 0;
+    }
+
+    if (!isspace(c)) {
+      ungetc(c, stream);
+      break;
+    }
+  }
+  if (c == '\0') {
+    *error = 1;
+    return 0;
+  }
+  if (!isdigit(c)) {
+    *error = 1;
+    return 0;
+  }
+  if (!(2 <= base && 36 >= base)) {
+    *error = 1;
+    return 0;
+  }
+  for (;;) {
+    if (EOF == (c = fgetc(stream)))
+      break;
+    if (c == '\0') {
+      ungetc(c, stream);
+      break;
+    }
+    int val = get_value(c, base);
+    if (-1 == val) {
+      ungetc(c, stream);
+      break;
+    }
+    if (ret_value * base > LONG_MAX - val) {
+      ungetc(c, stream);
+      errno = ERANGE;
+      *error = 1;
+      return 0;
+    }
+    ret_value *= base;
+    ret_value += val;
+  }
+  return ret_value;
+}
+
+int vfscanf(FILE *stream, const char *format, va_list ap) {
+  int rc = 0; // Upon successful completion, these functions shall return the
+              // number of successfully matched and assigned input items
+  int cont = 0;
+  int suppress = 0;
+  for (; *format; format++) {
+    if (*format != '%' && !cont) {
+      char c;
+      if (isspace(*format))
+        continue;
+      if (EOF == (c = fgetc(stream))) {
+        break;
+      }
+      if (*format == c) // TODO: Make sure this is the correct behaviour
+        continue;
+      // TODO: Make sure this is the correct behaviour
+      errno = EINVAL;
+      assert(0);
+      break;
+    }
+
+    if (*format == '%' && !cont) {
+      cont = 1;
+      continue;
+    }
+
+    int is_long = 0;
+    switch (*format) {
+    case 'l':
+      is_long++;
+      assert(is_long < 3);
+      cont = 1;
+      break;
+    case 'i': // Matches an optionally signed integer, whose format is the same
+              // as expected for the subject sequence of strtol() with 0 for the
+              // base argument.
+    case 'd': {
+      // Matches an optionally signed decimal integer, whose format is the
+      // same as expected for the subject sequence of strtol() with the value
+      // 10 for the base argument. In the absence of a size modifier, the
+      // application shall ensure that the corresponding argument is a pointer
+      // to int.
+      int err = 0;
+      int result = ftnum(stream, 10, &err);
+      if (err) {
+        cont = 0;
+        break;
+      }
+      if (!suppress) {
+        if (2 == is_long) {
+          *((long long *)va_arg(ap, long long *)) = result;
+        } else if (1 == is_long) {
+          *((long *)va_arg(ap, long *)) = result;
+        } else {
+          *((int *)va_arg(ap, int *)) = result;
+        }
+        rc++;
+      }
+      assert(0 == err);
+      cont = 0;
+      break;
+    }
+    case 'c': {
+      char result = fgetc(stream);
+      if (!suppress) {
+        *((char *)va_arg(ap, char *)) = result;
+        rc++;
+      }
+      cont = 0;
+      break;
+    }
+    case '*': // Assignment suppression
+      suppress = 1;
+      cont = 1;
+      break;
+    default:
+      printf("vfscanf: Got %c but not supported.\n", *format);
+      assert(0);
+      break;
+    }
+    if (!cont) {
+      suppress = 0;
+    }
+  }
+  return rc;
+}
+
+struct sscanf_cookie {
+  const char *s;
+};
+
+size_t sscanf_read(FILE *f, unsigned char *s, size_t l) {
+  struct sscanf_cookie *c = f->cookie;
+  if (!*(c->s)) {
+    return 0;
+  }
+  size_t r = 0;
+  for (; l && *(c->s); l--, c->s += 1) {
+    *s = *(c->s);
+    s++;
+    r++;
+  }
+  if (!(*(c->s)))
+    f->is_eof = 1;
+  /*
+  memcpy(s, c->s, l);
+  c->s += l;*/
+  return r;
+}
+
+int vsscanf(const char *s, const char *restrict format, va_list ap) {
+  struct sscanf_cookie c = {.s = s};
+  FILE f = {
+      .read = sscanf_read,
+      .cookie = &c,
+      .has_buffered_char = 0,
+      .is_eof = 0,
+      .has_error = 0,
+      .offset_in_file = 0,
+  };
+  return vfscanf(&f, format, ap);
+}
+
+int sscanf(const char *s, const char *restrict format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  int rc = vsscanf(s, format, ap);
+  va_end(ap);
+  return rc;
+}
diff --git a/userland/libc/string/strcasecmp.c b/userland/libc/string/strcasecmp.c
new file mode 100644
index 0000000..eed337b
--- /dev/null
+++ b/userland/libc/string/strcasecmp.c
@@ -0,0 +1,28 @@
+#include <strings.h>
+
+int strcasecmp(const char *s1, const char *s2) {
+  // The strcmp() function shall compare the string pointed to by s1
+  // to the string pointed to by s2.
+  int l1, l2, rc;
+  l1 = l2 = rc = 0;
+  for (; (*s1 || *s2);) {
+    if (tolower(*s1) != tolower(*s2))
+      rc++;
+    if (*s1) {
+      l1++;
+      s1++;
+    }
+    if (*s2) {
+      l2++;
+      s2++;
+    }
+  }
+
+  // Upon completion, strcmp() shall return an integer greater than,
+  // equal to, or less than 0, if the string pointed to by s1 is
+  // greater than, equal to, or less than the string pointed to by
+  // s2, respectively.
+  if (l2 > l1)
+    return -rc;
+  return rc;
+}
diff --git a/userland/libc/string/strcat.c b/userland/libc/string/strcat.c
new file mode 100644
index 0000000..c430698
--- /dev/null
+++ b/userland/libc/string/strcat.c
@@ -0,0 +1,13 @@
+#include <string.h>
+
+char *strcat(char *s1, const char *s2) {
+  strcpy(s1 + strlen(s1), s2);
+  return s1;
+  /*
+char *r = s1;
+for (; *s1; s1++)
+;
+for (; *s2; s2++, s1++)
+*s1 = *s2;
+return r;*/
+}
diff --git a/userland/libc/string/strchr.c b/userland/libc/string/strchr.c
new file mode 100644
index 0000000..1995547
--- /dev/null
+++ b/userland/libc/string/strchr.c
@@ -0,0 +1,11 @@
+#include <string.h>
+
+char *strchr(const char *s, int c) {
+  for (; *s; s++) {
+    if (*s == (char)c)
+      return (char*)s;
+  }
+  if ((char)c == '\0')
+    return (char *)s;
+  return NULL;
+}
diff --git a/userland/libc/string/strcmp.c b/userland/libc/string/strcmp.c
new file mode 100644
index 0000000..368b8fb
--- /dev/null
+++ b/userland/libc/string/strcmp.c
@@ -0,0 +1,29 @@
+#include <string.h>
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+int strcmp(const char *s1, const char *s2) {
+  // The strcmp() function shall compare the string pointed to by s1
+  // to the string pointed to by s2.
+  int l1, l2, rc;
+  l1 = l2 = rc = 0;
+  for (; *s1 || *s2;) {
+    if (*s1 != *s2)
+      rc++;
+    if (*s1) {
+      l1++;
+      s1++;
+    }
+    if (*s2) {
+      l2++;
+      s2++;
+    }
+  }
+
+  // Upon completion, strcmp() shall return an integer greater than,
+  // equal to, or less than 0, if the string pointed to by s1 is
+  // greater than, equal to, or less than the string pointed to by
+  // s2, respectively.
+  if (l2 > l1)
+    return -rc;
+  return rc;
+}
diff --git a/userland/libc/string/strcpy.c b/userland/libc/string/strcpy.c
new file mode 100644
index 0000000..9023fd1
--- /dev/null
+++ b/userland/libc/string/strcpy.c
@@ -0,0 +1,7 @@
+#include <string.h>
+
+char *strcpy(char *dest, const char *src) {
+  for (; (*dest = *src); dest++, src++)
+    ;
+  return dest;
+}
diff --git a/userland/libc/string/strcspn.c b/userland/libc/string/strcspn.c
new file mode 100644
index 0000000..2ad38d5
--- /dev/null
+++ b/userland/libc/string/strcspn.c
@@ -0,0 +1,14 @@
+#include <string.h>
+
+size_t strcspn(const char *s1, const char *s2) {
+  size_t r = 0;
+  for (; *s1; s1++) {
+    for (const char *t = s2; *t; t++) {
+      if (*s1 == *s2) {
+        r++;
+	break;
+      }
+    }
+  }
+  return r;
+}
diff --git a/userland/libc/string/strdup.c b/userland/libc/string/strdup.c
new file mode 100644
index 0000000..9e22f94
--- /dev/null
+++ b/userland/libc/string/strdup.c
@@ -0,0 +1,15 @@
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+// The strdup() function shall return a pointer to a new string, which is a
+// duplicate of the string pointed to by s. The returned pointer can be passed
+// to free(). A null pointer is returned if the new string cannot be created.
+char *strdup(const char *s) {
+  size_t l = strlen(s);
+  char *r = malloc(l + 1);
+  if (!r)
+    return NULL;
+  strcpy(r, s);
+  return r;
+}
diff --git a/userland/libc/string/strlcpy.c b/userland/libc/string/strlcpy.c
new file mode 100644
index 0000000..a2d3dd9
--- /dev/null
+++ b/userland/libc/string/strlcpy.c
@@ -0,0 +1,20 @@
+#include <string.h>
+
+// Copy string s2 to buffer s1 of size n.  At most n-1
+// chars will be copied.  Always NUL terminates (unless n == 0).
+// Returns strlen(s2); if retval >= n, truncation occurred.
+size_t *strlcpy(char *s1, const char *s2, size_t n) {
+  size_t tmp_n = n;
+  const char *os2 = s2;
+  for (; tmp_n; tmp_n--) {
+    if ((*s1++ = *s2++) == '\0')
+      break;
+  }
+  if (tmp_n == 0) {
+    if (n != 0)
+      *s1 = '\0'; /* NUL-terminate s1 */
+    while (*s2++)
+      ;
+  }
+  return s2 - os2 - 1;
+}
diff --git a/userland/libc/string/strlen.c b/userland/libc/string/strlen.c
new file mode 100644
index 0000000..8e3e77a
--- /dev/null
+++ b/userland/libc/string/strlen.c
@@ -0,0 +1,8 @@
+#include <string.h>
+
+size_t strlen(const char *s) {
+  const char *d = s;
+  for (; *s; s++)
+    ;
+  return s - d;
+}
diff --git a/userland/libc/string/strncasecmp.c b/userland/libc/string/strncasecmp.c
new file mode 100644
index 0000000..9ce8c04
--- /dev/null
+++ b/userland/libc/string/strncasecmp.c
@@ -0,0 +1,29 @@
+#include <strings.h>
+#include <stddef.h>
+
+int strncasecmp(const char *s1, const char *s2, size_t n) {
+  // The strcmp() function shall compare the string pointed to by s1
+  // to the string pointed to by s2.
+  int l1, l2, rc;
+  l1 = l2 = rc = 0;
+  for (; (*s1 || *s2) && n > 0; n--) {
+    if (tolower(*s1) != tolower(*s2))
+      rc++;
+    if (*s1) {
+      l1++;
+      s1++;
+    }
+    if (*s2) {
+      l2++;
+      s2++;
+    }
+  }
+
+  // Upon completion, strcmp() shall return an integer greater than,
+  // equal to, or less than 0, if the string pointed to by s1 is
+  // greater than, equal to, or less than the string pointed to by
+  // s2, respectively.
+  if (l2 > l1)
+    return -rc;
+  return rc;
+}
diff --git a/userland/libc/string/strncmp.c b/userland/libc/string/strncmp.c
new file mode 100644
index 0000000..fd46189
--- /dev/null
+++ b/userland/libc/string/strncmp.c
@@ -0,0 +1,28 @@
+#include <string.h>
+
+int strncmp(const char *s1, const char *s2, size_t n) {
+  // The strcmp() function shall compare the string pointed to by s1
+  // to the string pointed to by s2.
+  int l1, l2, rc;
+  l1 = l2 = rc = 0;
+  for (; (*s1 || *s2) && n > 0; n--) {
+    if (*s1 != *s2)
+      rc++;
+    if (*s1) {
+      l1++;
+      s1++;
+    }
+    if (*s2) {
+      l2++;
+      s2++;
+    }
+  }
+
+  // Upon completion, strcmp() shall return an integer greater than,
+  // equal to, or less than 0, if the string pointed to by s1 is
+  // greater than, equal to, or less than the string pointed to by
+  // s2, respectively.
+  if (l2 > l1)
+    return -rc;
+  return rc;
+}
diff --git a/userland/libc/string/strncpy.c b/userland/libc/string/strncpy.c
new file mode 100644
index 0000000..0e88c63
--- /dev/null
+++ b/userland/libc/string/strncpy.c
@@ -0,0 +1,13 @@
+#include <string.h>
+
+char *strncpy(char *s1, const char *s2, size_t n) {
+  char *rc = s1;
+  for (; n > 0; s1++, s2++, n--) {
+    *s1 = *s2;
+    if (!*s2)
+      break;
+  }
+  for (; n > 0; n--,s1++)
+    *s1 = '\0';
+  return rc;
+}
diff --git a/userland/libc/string/strndup.c b/userland/libc/string/strndup.c
new file mode 100644
index 0000000..ffb2088
--- /dev/null
+++ b/userland/libc/string/strndup.c
@@ -0,0 +1,22 @@
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+// The strndup() function shall be equivalent to the strdup() function,
+// duplicating the provided s in a new block of memory allocated as if
+// by using malloc(), with the exception being that strndup() copies at
+// most size plus one bytes into the newly allocated memory, terminating
+// the new string with a NUL character. If the length of s is larger
+// than size, only size bytes shall be duplicated. If size is larger
+// than the length of s, all bytes in s shall be copied into the new
+// memory buffer, including the terminating NUL character. The newly
+// created string shall always be properly terminated.
+char *strndup(const char *s, size_t size) {
+  size_t l = strlen(s);
+  size_t real_l = min(l, size);
+  char *r = malloc(real_l + 1);
+  if (!r)
+    return NULL;
+  strlcpy(r, s, real_l);
+  return r;
+}
diff --git a/userland/libc/string/strnlen.c b/userland/libc/string/strnlen.c
new file mode 100644
index 0000000..86df42e
--- /dev/null
+++ b/userland/libc/string/strnlen.c
@@ -0,0 +1,9 @@
+#include <string.h>
+
+size_t strnlen(const char *s, size_t maxlen) {
+  size_t i;
+  for (i = 0; i < maxlen; i++)
+    if (s[i] == 0)
+      break;
+  return i;
+}
diff --git a/userland/libc/string/strpbrk.c b/userland/libc/string/strpbrk.c
new file mode 100644
index 0000000..fb16b0c
--- /dev/null
+++ b/userland/libc/string/strpbrk.c
@@ -0,0 +1,12 @@
+#include <string.h>
+
+char *strpbrk(const char *s1, const char *s2) {
+  for (; *s1; s1++) {
+    for (const char *t = s2; *t; t++) {
+      if (*s1 == *t) {
+        return s1;
+      }
+    }
+  }
+  return NULL;
+}
diff --git a/userland/libc/string/strrchr.c b/userland/libc/string/strrchr.c
new file mode 100644
index 0000000..a44199a
--- /dev/null
+++ b/userland/libc/string/strrchr.c
@@ -0,0 +1,12 @@
+#include <string.h>
+
+char *strrchr(const char *s, int c) {
+  char *last = NULL;
+  for (; *s; s++) {
+    if (*s == (char)c)
+      last = (char *)s;
+  }
+  if ((char)c == '\0')
+    last = (char*)s;
+  return last;
+}
diff --git a/userland/libc/string/strspn.c b/userland/libc/string/strspn.c
new file mode 100644
index 0000000..2a7d3ae
--- /dev/null
+++ b/userland/libc/string/strspn.c
@@ -0,0 +1,18 @@
+#include <string.h>
+
+size_t strspn(const char *s1, const char *s2) {
+  size_t r = 0;
+  for (; *s1; s1++) {
+    int e = 0;
+    for (const char *t = s2; *t; t++) {
+      if (*s1 == *t) {
+        e = 1;
+        break;
+      }
+    }
+    if (!e)
+      break;
+    r++;
+  }
+  return r;
+}
diff --git a/userland/libc/string/strstr.c b/userland/libc/string/strstr.c
new file mode 100644
index 0000000..20b9dc2
--- /dev/null
+++ b/userland/libc/string/strstr.c
@@ -0,0 +1,21 @@
+#include <string.h>
+
+char *strstr(const char *s1, const char *s2) {
+  // If s2 points to a string with zero length, the function shall return s1.
+  if ('\0' == *s2)
+    return s1;
+  for (; *s1; s1++) {
+    const char *t1 = s1;
+    const char *t2 = s2;
+    int is_dif = 0;
+    for (; *t2 && *t1; t1++, t2++) {
+      if (*t2 != *t1) {
+        is_dif = 1;
+        break;
+      }
+    }
+    if (!is_dif)
+      return s1;
+  }
+  return NULL;
+}
diff --git a/userland/libc/string/strtok.c b/userland/libc/string/strtok.c
new file mode 100644
index 0000000..7b8d0e3
--- /dev/null
+++ b/userland/libc/string/strtok.c
@@ -0,0 +1,26 @@
+#include <string.h>
+
+char *strtok_s;
+
+char *strtok(char *restrict s, const char *restrict sep) {
+  if (s) {
+    strtok_s = s;
+    return strtok(NULL, sep);
+  }
+	if(!strtok_s)
+		return NULL;
+  char *e = strpbrk(strtok_s, sep);
+  if (!e) {
+	  char *r = strtok_s;
+	  strtok_s = NULL;
+    return r;
+  }
+  *e = '\0';
+  e--;
+  for (; *sep; sep++)
+    e++;
+  e++;
+  char *r = strtok_s;
+  strtok_s = e;
+  return r;
+}
diff --git a/userland/libc/strings.h b/userland/libc/strings.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/strings.h
diff --git a/userland/libc/sys/mman.h b/userland/libc/sys/mman.h
new file mode 100644
index 0000000..e3ff734
--- /dev/null
+++ b/userland/libc/sys/mman.h
@@ -0,0 +1,8 @@
+#ifndef MMAP_H
+#define MMAP_H
+#include <stdint.h>
+#include <stddef.h>
+
+void *mmap(void *addr, size_t length, int prot, int flags, int fd,
+           size_t offset);
+#endif
diff --git a/userland/libc/sys/mman/mmap.c b/userland/libc/sys/mman/mmap.c
new file mode 100644
index 0000000..b9ad3a2
--- /dev/null
+++ b/userland/libc/sys/mman/mmap.c
@@ -0,0 +1,19 @@
+#include <syscall.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+extern int errno;
+
+void *mmap(void *addr, size_t length, int prot, int flags, int fd,
+           size_t offset) {
+  SYS_MMAP_PARAMS args = {
+      .addr = addr,
+      .length = length,
+      .prot = prot,
+      .flags = flags,
+      .fd = fd,
+      .offset = offset,
+  };
+//  return (void*)syscall(SYS_MMAP, &args, 0, 0, 0, 0);
+  RC_ERRNO(syscall(SYS_MMAP, &args, 0, 0, 0, 0));
+}
diff --git a/userland/libc/sys/stat.h b/userland/libc/sys/stat.h
new file mode 100644
index 0000000..2fe6cdc
--- /dev/null
+++ b/userland/libc/sys/stat.h
@@ -0,0 +1,30 @@
+#ifndef STAT_H
+#define STAT_H
+#include <sys/types.h>
+#include <time.h>
+
+struct stat {
+  dev_t st_dev;            // Device ID of device containing file.
+  ino_t st_ino;            // File serial number.
+  mode_t st_mode;          // Mode of file (see below).
+  nlink_t st_nlink;        // Number of hard links to the file.
+  uid_t st_uid;            // User ID of file.
+  gid_t st_gid;            // Group ID of file.
+  dev_t st_rdev;           // Device ID (if file is character or block special).
+  off_t st_size;           // For regular files, the file size in bytes.
+                           // For symbolic links, the length in bytes of the
+                           // pathname contained in the symbolic link.
+                           // For a shared memory object, the length in bytes.
+                           // For a typed memory object, the length in bytes.
+                           // For other file types, the use of this field is
+                           // unspecified.
+  struct timespec st_atime; // Last data access timestamp.
+  struct timespec st_mtime; // Last data modification timestamp.
+  struct timespec st_ctime; // Last file status change timestamp.
+  blksize_t st_blksize;    // A file system-specific preferred I/O block size
+                           // for this object. In some file system types, this
+                           // may vary from file to file.
+  blkcnt_t st_blocks;      // Number of blocks allocated for this object.
+};
+int stat(const char *path, struct stat *buf);
+#endif
diff --git a/userland/libc/sys/stat/mkdir.c b/userland/libc/sys/stat/mkdir.c
new file mode 100644
index 0000000..c057fa7
--- /dev/null
+++ b/userland/libc/sys/stat/mkdir.c
@@ -0,0 +1,9 @@
+#include <sys/stat.h>
+#include <assert.h>
+
+int mkdir(const char *path, mode_t mode) {
+	(void)path;
+	(void)mode;
+	assert(0); // TODO: Implement
+		   return 0;
+}
diff --git a/userland/libc/sys/stat/stat.c b/userland/libc/sys/stat/stat.c
new file mode 100644
index 0000000..e37223e
--- /dev/null
+++ b/userland/libc/sys/stat/stat.c
@@ -0,0 +1,13 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <syscall.h>
+
+int stat(const char *path, struct stat *buf) {
+  SYS_STAT_PARAMS args = {
+      .pathname = path,
+      .statbuf = buf,
+  };
+  RC_ERRNO(syscall(SYS_STAT, &args, 0, 0, 0, 0));
+}
diff --git a/userland/libc/sys/time/gettimeofday.c b/userland/libc/sys/time/gettimeofday.c
new file mode 100644
index 0000000..e172cf2
--- /dev/null
+++ b/userland/libc/sys/time/gettimeofday.c
@@ -0,0 +1,5 @@
+#include <sys/time.h>
+#include <time.h>
+
+static int return_tod =0;
+int gettimeofday(struct timeval *tp, void *tzp) {return return_tod++;}
diff --git a/userland/libc/sys/types.h b/userland/libc/sys/types.h
new file mode 100644
index 0000000..ffcf281
--- /dev/null
+++ b/userland/libc/sys/types.h
@@ -0,0 +1,27 @@
+#ifndef TYPES_H
+#define TYPES_H
+typedef unsigned int ino_t;
+
+typedef int mode_t;
+
+typedef int nlink_t;
+typedef int uid_t;
+typedef int gid_t;
+typedef int id_t;
+
+typedef int blkcnt_t;
+typedef int off_t;
+
+typedef int dev_t;
+typedef unsigned int fsblkcnt_t;
+typedef unsigned int fsfilcnt_t;
+typedef unsigned int ino_t;
+//typedef unsigned int size_t;
+
+typedef int blksize_t;
+typedef int pid_t;
+typedef int ssize_t;
+
+//typedef int clock_t;
+typedef int time_t;
+#endif
diff --git a/userland/libc/syscall.h b/userland/libc/syscall.h
new file mode 100644
index 0000000..952492f
--- /dev/null
+++ b/userland/libc/syscall.h
@@ -0,0 +1,149 @@
+#ifndef SYSCALL_H
+#define SYSCALL_H
+#include "socket.h"
+#include <stddef.h>
+#include <stdint.h>
+
+#define SYS_OPEN 0
+#define SYS_READ 1
+#define SYS_WRITE 2
+#define SYS_PREAD 3
+#define SYS_PWRITE 4
+#define SYS_FORK 5
+#define SYS_EXEC 6
+#define SYS_GETPID 7
+#define SYS_EXIT 8
+#define SYS_WAIT 9
+#define SYS_BRK 10
+#define SYS_SBRK 11
+#define SYS_PIPE 12
+#define SYS_DUP2 13
+#define SYS_CLOSE 14
+#define SYS_OPENPTY 15
+#define SYS_POLL 16
+#define SYS_MMAP 17
+#define SYS_ACCEPT 18
+#define SYS_BIND 19
+#define SYS_SOCKET 20
+#define SYS_SHM_OPEN 21
+#define SYS_FTRUNCATE 22
+#define SYS_STAT 23
+#define SYS_MSLEEP 24
+#define SYS_UPTIME 25
+
+int syscall(uint32_t eax, uint32_t ebx, uint32_t ecx, uint32_t edx,
+            uint32_t esi, uint32_t edi);
+int s_syscall(int sys);
+
+extern int errno;
+#define RC_ERRNO(_rc)                                                          \
+  {                                                                            \
+    int c = _rc;                                                               \
+    if (c < 0) {                                                               \
+      errno = -(c);                                                            \
+      return -1;                                                               \
+    }                                                                          \
+    return c;                                                                  \
+  }
+
+typedef int mode_t;
+
+typedef struct SYS_OPEN_PARAMS {
+  char *file;
+  int flags;
+  int mode;
+} __attribute__((packed)) SYS_OPEN_PARAMS;
+
+typedef struct SYS_PREAD_PARAMS {
+  int fd;
+  void *buf;
+  size_t count;
+  size_t offset;
+} __attribute__((packed)) SYS_PREAD_PARAMS;
+
+typedef struct SYS_READ_PARAMS {
+  int fd;
+  void *buf;
+  size_t count;
+} __attribute__((packed)) SYS_READ_PARAMS;
+
+typedef struct SYS_PWRITE_PARAMS {
+  int fd;
+  void *buf;
+  size_t count;
+  size_t offset;
+} __attribute__((packed)) SYS_PWRITE_PARAMS;
+
+typedef struct SYS_WRITE_PARAMS {
+  int fd;
+  void *buf;
+  size_t count;
+} __attribute__((packed)) SYS_WRITE_PARAMS;
+
+typedef struct SYS_EXEC_PARAMS {
+  char *path;
+  char **argv;
+} __attribute__((packed)) SYS_EXEC_PARAMS;
+
+typedef struct SYS_DUP2_PARAMS {
+  int org_fd;
+  int new_fd;
+} __attribute__((packed)) SYS_DUP2_PARAMS;
+
+typedef struct SYS_OPENPTY_PARAMS {
+  int *amaster;
+  int *aslave;
+  char *name;
+  /*const struct termios*/ void *termp;
+  /*const struct winsize*/ void *winp;
+} __attribute__((packed)) SYS_OPENPTY_PARAMS;
+
+typedef struct SYS_POLL_PARAMS {
+  struct pollfd *fds;
+  size_t nfds;
+  int timeout;
+} __attribute__((packed)) SYS_POLL_PARAMS;
+
+typedef struct SYS_MMAP_PARAMS {
+  void *addr;
+  size_t length;
+  int prot;
+  int flags;
+  int fd;
+  size_t offset;
+} __attribute__((packed)) SYS_MMAP_PARAMS;
+
+typedef struct SYS_SOCKET_PARAMS {
+  int domain;
+  int type;
+  int protocol;
+} __attribute__((packed)) SYS_SOCKET_PARAMS;
+
+typedef struct SYS_BIND_PARAMS {
+  int sockfd;
+  const struct sockaddr *addr;
+  socklen_t addrlen;
+} __attribute__((packed)) SYS_BIND_PARAMS;
+
+typedef struct SYS_ACCEPT_PARAMS {
+  int socket;
+  struct sockaddr *address;
+  socklen_t *address_len;
+} __attribute__((packed)) SYS_ACCEPT_PARAMS;
+
+typedef struct SYS_SHM_OPEN_PARAMS {
+  const char *name;
+  int oflag;
+  mode_t mode;
+} __attribute__((packed)) SYS_SHM_OPEN_PARAMS;
+
+typedef struct SYS_FTRUNCATE_PARAMS {
+  int fildes;
+  uint64_t length;
+} __attribute__((packed)) SYS_FTRUNCATE_PARAMS;
+
+typedef struct SYS_STAT_PARAMS {
+  const char *pathname;
+  struct stat *statbuf;
+} __attribute__((packed)) SYS_STAT_PARAMS;
+#endif
diff --git a/userland/libc/time.h b/userland/libc/time.h
new file mode 100644
index 0000000..771e430
--- /dev/null
+++ b/userland/libc/time.h
@@ -0,0 +1,20 @@
+#include <sys/types.h>
+
+struct tm {
+	int tm_sec;
+	int tm_min;
+	int tm_hour;
+	int tm_mday;
+	int tm_mon;
+	int tm_year;
+	int tm_wday;
+	int tm_yday;
+	int tm_isdst;
+	long __tm_gmtoff;
+	const char *__tm_zone;
+};
+
+struct timespec {
+  time_t tv_sec; // Seconds.
+  long tv_nsec;  // Nanoseconds.
+};
diff --git a/userland/libc/time/clock_gettime.c b/userland/libc/time/clock_gettime.c
new file mode 100644
index 0000000..15f0cb7
--- /dev/null
+++ b/userland/libc/time/clock_gettime.c
@@ -0,0 +1,14 @@
+#include <syscall.h>
+#include <time.h>
+
+int clock_gettime(clockid_t clock_id, struct timespec *tp) {
+  tp->tv_sec = 0;
+  tp->tv_nsec = 0;
+  return 0;
+  /*
+SYS_CLOCK_GETTIME_PARAMS args = {
+.clk = clock_id,
+.ts = tp,
+};
+return syscall(SYS_CLOCK_GETTIME, &args);*/
+}
diff --git a/userland/libc/time/ctime_r.c b/userland/libc/time/ctime_r.c
new file mode 100644
index 0000000..66e6416
--- /dev/null
+++ b/userland/libc/time/ctime_r.c
@@ -0,0 +1,13 @@
+#include <string.h>
+#include <time.h>
+
+// TODO: Implement this
+
+// Time, formatting and parsing are some of the most annoying parts of
+// programming. Lets just hope this function is not important
+char *ctime_r(const time_t *clock, char *buf) {
+  (void)clock;
+  size_t l = strlen(buf);
+  memset(buf, '0', l);
+  return buf;
+}
diff --git a/userland/libc/time/gmtime.c b/userland/libc/time/gmtime.c
new file mode 100644
index 0000000..44e0ff3
--- /dev/null
+++ b/userland/libc/time/gmtime.c
@@ -0,0 +1,21 @@
+#include <time.h>
+
+struct tm gmtime_r = {
+    .tm_sec = 0,
+    .tm_min = 0,
+    .tm_hour = 0,
+    .tm_mday = 0,
+    .tm_mon = 0,
+    .tm_year = 0,
+    .tm_wday = 0,
+    .tm_yday = 0,
+    .tm_isdst = 0,
+    .__tm_gmtoff = 0,
+    .__tm_zone = 0,
+};
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/gmtime.html
+struct tm *gmtime(const time_t *timer) {
+  // TODO: Implement
+  return &gmtime_r;
+}
diff --git a/userland/libc/time/localtime.c b/userland/libc/time/localtime.c
new file mode 100644
index 0000000..40ca351
--- /dev/null
+++ b/userland/libc/time/localtime.c
@@ -0,0 +1,21 @@
+#include <time.h>
+
+  struct tm localtime_r = {
+      .tm_sec = 0,
+      .tm_min = 0,
+      .tm_hour = 0,
+      .tm_mday = 0,
+      .tm_mon = 0,
+      .tm_year = 0,
+      .tm_wday = 0,
+      .tm_yday = 0,
+      .tm_isdst = 0,
+      .__tm_gmtoff = 0,
+      .__tm_zone = 0,
+  };
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/localtime.html
+struct tm *localtime(const time_t *timer) {
+  // TODO: Implement
+  return &localtime_r;
+}
diff --git a/userland/libc/time/strftime.c b/userland/libc/time/strftime.c
new file mode 100644
index 0000000..30a080d
--- /dev/null
+++ b/userland/libc/time/strftime.c
@@ -0,0 +1,7 @@
+#include <time.h>
+#include <stddef.h>
+
+size_t strftime(char *restrict s, size_t maxsize,
+       const char *restrict format, const struct tm *restrict timeptr) {
+	return 0;
+}
diff --git a/userland/libc/time/time.c b/userland/libc/time/time.c
new file mode 100644
index 0000000..9931b71
--- /dev/null
+++ b/userland/libc/time/time.c
@@ -0,0 +1,9 @@
+#include <time.h>
+
+time_t time(time_t *tloc) {
+  struct timespec ts;
+  clock_gettime(CLOCK_REALTIME, &ts);
+  if (tloc)
+    *tloc = ts.tv_sec;
+  return ts.tv_sec;
+}
diff --git a/userland/libc/ubsan.c b/userland/libc/ubsan.c
new file mode 100644
index 0000000..9ac9879
--- /dev/null
+++ b/userland/libc/ubsan.c
@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <ubsan.h>
+
+void ubsan_log(const char *cause, struct source_location source) {
+  printf("UBSAN\n");
+  printf("%s: %s : %d\n", cause, source.file_name, source.line);
+  for (;;)
+    ;
+}
+
+void __ubsan_handle_shift_out_of_bounds(struct ShiftOutOfBoundsData *data,
+                                        unsigned long lhs, unsigned long rhs) {
+  (void)lhs;
+  (void)rhs;
+  ubsan_log("handle_shift_out_of_bounds", data->location);
+}
+
+void __ubsan_handle_add_overflow(struct OverflowData *data, unsigned long lhs,
+                                 unsigned long rhs) {
+  (void)lhs;
+  (void)rhs;
+  ubsan_log("handle_add_overflow", data->location);
+}
+
+void __ubsan_handle_sub_overflow(struct OverflowData *data, unsigned long lhs,
+                                 unsigned long rhs) {
+  (void)lhs;
+  (void)rhs;
+  ubsan_log("handle_sub_overflow", data->location);
+}
+
+void __ubsan_handle_negate_overflow(struct OverflowData *data, unsigned long lhs,
+                                 unsigned long rhs) {
+  (void)lhs;
+  (void)rhs;
+  ubsan_log("handle_negate_overflow", data->location);
+}
+
+void __ubsan_handle_mul_overflow(struct OverflowData *data, unsigned long lhs,
+                                 unsigned long rhs) {
+  (void)lhs;
+  (void)rhs;
+  ubsan_log("handle_mul_overflow", data->location);
+}
+
+void __ubsan_handle_out_of_bounds(struct OutOfBoundsData *data, void *index) {
+  (void)index;
+  ubsan_log("handle_out_of_bounds", data->location);
+}
diff --git a/userland/libc/ubsan.h b/userland/libc/ubsan.h
new file mode 100644
index 0000000..dac5407
--- /dev/null
+++ b/userland/libc/ubsan.h
@@ -0,0 +1,79 @@
+#include <stdint.h>
+
+enum { type_kind_int = 0, type_kind_float = 1, type_unknown = 0xffff };
+
+struct type_descriptor {
+  uint16_t type_kind;
+  uint16_t type_info;
+  char type_name[1];
+};
+
+struct source_location {
+  const char *file_name;
+  union {
+    unsigned long reported;
+    struct {
+      uint32_t line;
+      uint32_t column;
+    };
+  };
+};
+
+struct OverflowData {
+  struct source_location location;
+  struct type_descriptor *type;
+};
+
+struct type_mismatch_data {
+  struct source_location location;
+  struct type_descriptor *type;
+  unsigned long alignment;
+  unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_v1 {
+  struct source_location location;
+  struct type_descriptor *type;
+  unsigned char log_alignment;
+  unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_common {
+  struct source_location *location;
+  struct type_descriptor *type;
+  unsigned long alignment;
+  unsigned char type_check_kind;
+};
+
+struct nonnull_arg_data {
+  struct source_location location;
+  struct source_location attr_location;
+  int arg_index;
+};
+
+struct OutOfBoundsData {
+  struct source_location location;
+  struct type_descriptor *array_type;
+  struct type_descriptor *index_type;
+};
+
+struct ShiftOutOfBoundsData {
+  struct source_location location;
+  struct type_descriptor *lhs_type;
+  struct type_descriptor *rhs_type;
+};
+
+struct unreachable_data {
+  struct source_location location;
+};
+
+struct invalid_value_data {
+  struct source_location location;
+  struct type_descriptor *type;
+};
+
+struct alignment_assumption_data {
+  struct source_location location;
+  struct source_location assumption_location;
+  struct type_descriptor *type;
+};
diff --git a/userland/libc/unistd.h b/userland/libc/unistd.h
new file mode 100644
index 0000000..b1e3434
--- /dev/null
+++ b/userland/libc/unistd.h
@@ -0,0 +1,14 @@
+#ifndef UNISTD_H
+#define UNISTD_H
+#include <stddef.h>
+
+extern int opterr, optind, optopt;
+extern char *optarg;
+
+int close(int fildes);
+int ftruncate(int fildes, size_t length);
+int execv(char *path, char **argv);
+int pipe(int fd[2]);
+int dup2(int org_fd, int new_fd);
+int getopt(int argc, char * const argv[], const char *optstring);
+#endif
diff --git a/userland/libc/unistd/_exit.c b/userland/libc/unistd/_exit.c
new file mode 100644
index 0000000..c6d64be
--- /dev/null
+++ b/userland/libc/unistd/_exit.c
@@ -0,0 +1,8 @@
+#include <syscall.h>
+#include <unistd.h>
+
+// FIXME: Technically exit and _exit are different but this
+// stackoverflow answer says that it does not usually matter. So lets
+// hope that is the case.
+// https://stackoverflow.com/a/5423108
+void _exit(int status) { syscall(SYS_EXIT, (void *)status, 0, 0, 0, 0); }
diff --git a/userland/libc/unistd/execvp.c b/userland/libc/unistd/execvp.c
new file mode 100644
index 0000000..573e822
--- /dev/null
+++ b/userland/libc/unistd/execvp.c
@@ -0,0 +1,8 @@
+#include <unistd.h>
+#include <syscall.h>
+
+// FIXME: Path resolution
+int execvp(const char *file, char *const argv[]) {
+  struct SYS_EXEC_PARAMS args = {.path = file, .argv = argv};
+  return syscall(SYS_EXEC, &args, 0, 0, 0, 0);
+}
diff --git a/userland/libc/unistd/getopt.c b/userland/libc/unistd/getopt.c
new file mode 100644
index 0000000..a026b59
--- /dev/null
+++ b/userland/libc/unistd/getopt.c
@@ -0,0 +1,14 @@
+#include <assert.h>
+#include <unistd.h>
+
+int opterr, optind, optopt;
+char *optarg;
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html
+int getopt(int argc, char *const argv[], const char *optstring) {
+  // TODO
+  optind = 1;
+  optarg = NULL;
+  //  assert(0);
+  return -1;
+}
diff --git a/userland/libc/unistd/getpid.c b/userland/libc/unistd/getpid.c
new file mode 100644
index 0000000..8aeef10
--- /dev/null
+++ b/userland/libc/unistd/getpid.c
@@ -0,0 +1,7 @@
+#include <unistd.h>
+#include <syscall.h>
+#include <sys/types.h>
+
+pid_t getpid(void) {
+    return s_syscall(SYS_GETPID);
+}
diff --git a/userland/libc/unistd/msleep.c b/userland/libc/unistd/msleep.c
new file mode 100644
index 0000000..0b016c6
--- /dev/null
+++ b/userland/libc/unistd/msleep.c
@@ -0,0 +1,6 @@
+// Not standard, but it feels like it should be.
+#include <syscall.h>
+#include <unistd.h>
+#include <stdint.h>
+
+void msleep(uint32_t ms) { syscall(SYS_MSLEEP, (void *)ms, 0, 0, 0, 0); }
diff --git a/userland/libc/unistd/unlink.c b/userland/libc/unistd/unlink.c
new file mode 100644
index 0000000..ccac0df
--- /dev/null
+++ b/userland/libc/unistd/unlink.c
@@ -0,0 +1,7 @@
+#include <unistd.h>
+
+int unlink(const char *path) {
+  // TODO
+  printf("TODO: Implement unlink");
+  return 0;
+}
diff --git a/userland/libc/unistd/uptime.c b/userland/libc/unistd/uptime.c
new file mode 100644
index 0000000..090a0e5
--- /dev/null
+++ b/userland/libc/unistd/uptime.c
@@ -0,0 +1,6 @@
+// Not standard, but it feels like it should be.
+#include <stdint.h>
+#include <syscall.h>
+#include <unistd.h>
+
+uint32_t uptime(void) { return syscall(SYS_UPTIME, 0, 0, 0, 0, 0); }
diff --git a/userland/libc/wchar.h b/userland/libc/wchar.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/wchar.h
diff --git a/userland/libc/wctype.h b/userland/libc/wctype.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/userland/libc/wctype.h