LibC: Add fflush() and buffer writes to file descriptors

6 files changed, 40 insertions, 73 deletions

diff --git a/userland/libc/include/stdio.h b/userland/libc/include/stdio.h
index 43700e0..8ac4e59 100644
--- a/userland/libc/include/stdio.h
+++ b/userland/libc/include/stdio.h
@@ -28,6 +28,7 @@ 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);
+  void (*fflush)(FILE *);
   long offset_in_file;
   int buffered_char;
   int has_buffered_char;
@@ -35,6 +36,8 @@ struct __IO_FILE {
   uint8_t is_eof;
   uint8_t has_error;
   uint64_t file_size;
+  uint8_t *write_buffer;
+  uint32_t write_buffer_stored;
   uint8_t *read_buffer;
   uint32_t read_buffer_stored;
   uint32_t read_buffer_has_read;
@@ -44,6 +47,7 @@ struct __IO_FILE {
 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);
+void fflush_fd(FILE *f);
 
 typedef struct {
   int fd;
@@ -114,8 +118,6 @@ 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);
-size_t getdelim(char ** lineptr, size_t * n,
-       int delimiter, FILE * stream);
-size_t getline(char ** lineptr, size_t * n,
-       FILE * stream);
+size_t getdelim(char **lineptr, size_t *n, int delimiter, FILE *stream);
+size_t getline(char **lineptr, size_t *n, FILE *stream);
 #endif
diff --git a/userland/libc/libc.c b/userland/libc/libc.c
index dafd502..5fcf9fa 100644
--- a/userland/libc/libc.c
+++ b/userland/libc/libc.c
@@ -105,7 +105,7 @@ FILE *__stderr_FILE;
 #define stderr __stderr_FILE
 
 void _libc_setup(void) {
-  __stdin_FILE = malloc(sizeof(FILE));
+  __stdin_FILE = calloc(1, sizeof(FILE));
   __stdin_FILE->write = write_fd;
   __stdin_FILE->read = read_fd;
   __stdin_FILE->seek = NULL;
@@ -113,8 +113,9 @@ void _libc_setup(void) {
   __stdin_FILE->has_error = 0;
   __stdin_FILE->cookie = NULL;
   __stdin_FILE->fd = 0;
+  __stdin_FILE->fflush = fflush_fd;
 
-  __stdout_FILE = malloc(sizeof(FILE));
+  __stdout_FILE = calloc(1, sizeof(FILE));
   __stdout_FILE->write = write_fd;
   __stdout_FILE->read = read_fd;
   __stdout_FILE->is_eof = 0;
@@ -122,14 +123,16 @@ void _libc_setup(void) {
   __stdout_FILE->seek = NULL;
   __stdout_FILE->cookie = NULL;
   __stdout_FILE->fd = 1;
+  __stdout_FILE->fflush = fflush_fd;
 
-  __stderr_FILE = malloc(sizeof(FILE));
+  __stderr_FILE = calloc(1, sizeof(FILE));
   __stderr_FILE->write = write_fd;
   __stderr_FILE->read = read_fd;
   __stderr_FILE->is_eof = 0;
   __stderr_FILE->has_error = 0;
   __stderr_FILE->cookie = NULL;
   __stderr_FILE->fd = 2;
+  __stderr_FILE->fflush = fflush_fd;
 }
 
 // Functions preserve the registers ebx, esi, edi, ebp, and esp; while
diff --git a/userland/libc/stdio/fflush.c b/userland/libc/stdio/fflush.c
index 7a37c79..3042efa 100644
--- a/userland/libc/stdio/fflush.c
+++ b/userland/libc/stdio/fflush.c
@@ -2,6 +2,7 @@
 
 // https://pubs.opengroup.org/onlinepubs/9699919799/functions/fflush.html
 int fflush(FILE *stream) {
-  // FIXME: Implement
+  if (stream->fflush)
+    stream->fflush(stream);
   return 0;
 }
diff --git a/userland/libc/stdio/stdin.c b/userland/libc/stdio/stdin.c
index 2ced1a0..c424cc5 100644
--- a/userland/libc/stdio/stdin.c
+++ b/userland/libc/stdio/stdin.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-size_t write_fd(FILE *f, const unsigned char *s, size_t l) {
+size_t raw_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;
@@ -12,6 +12,27 @@ size_t write_fd(FILE *f, const unsigned char *s, size_t l) {
   return rc;
 }
 
+void fflush_fd(FILE *f) {
+  raw_write_fd(f, f->write_buffer, f->write_buffer_stored);
+  f->write_buffer_stored = 0;
+}
+
+size_t write_fd(FILE *f, const unsigned char *s, size_t l) {
+  if (!f->write_buffer) {
+    f->write_buffer = malloc(4096);
+    f->write_buffer_stored = 0;
+  }
+  if (l > 4096) {
+    return raw_write_fd(f, s, l);
+  }
+  if (f->write_buffer_stored + l > 4096) {
+    fflush_fd(f);
+  }
+  memcpy(f->write_buffer + f->write_buffer_stored, s, l);
+  f->write_buffer_stored += l;
+  return l;
+}
+
 size_t non_cache_read_fd(FILE *f, unsigned char *s, size_t l) {
   int rc = pread(f->fd, s, l, f->offset_in_file);
   if (rc == 0)
@@ -32,7 +53,7 @@ size_t read_fd(FILE *f, unsigned char *s, size_t l) {
   // syscalls
   if (l >= 4096) {
     // Invalidate the cache
-f->read_buffer_stored = 0;
+    f->read_buffer_stored = 0;
 
     size_t rc = non_cache_read_fd(f, s, l);
     f->offset_in_file += rc;
diff --git a/userland/libc/stdio/vdprintf.c b/userland/libc/stdio/vdprintf.c
index b3fa065..2724c2e 100644
--- a/userland/libc/stdio/vdprintf.c
+++ b/userland/libc/stdio/vdprintf.c
@@ -3,75 +3,14 @@
 #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,
+      .fflush = fflush_fd,
+      .write_buffer = NULL,
   };
   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
index f8d56ea..b2d4902 100644
--- a/userland/libc/stdio/vfprintf.c
+++ b/userland/libc/stdio/vfprintf.c
@@ -249,5 +249,6 @@ int vfprintf(FILE *f, const char *fmt, va_list ap) {
       precision = -1;
     }
   }
+  fflush(f);
   return rc;
 }