Kernel/LibC: Add chdir function and syscall

7 files changed, 41 insertions, 8 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index e7d67dd..eb8a90f 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -1,7 +1,7 @@
 CC="i686-sb-gcc"
 AS="i686-sb-as"
-OBJ = arch/i386/boot.o init/kernel.o cpu/gdt.o cpu/reload_gdt.o cpu/idt.o cpu/io.o libc/stdio/print.o drivers/keyboard.o log.o drivers/pit.o libc/string/memcpy.o libc/string/strlen.o libc/string/memcmp.o drivers/ata.o libc/string/memset.o cpu/syscall.o  read_eip.o libc/exit/assert.o process.o cpu/int_syscall.o libc/string/strcpy.o arch/i386/mmu.o kmalloc.o fs/ext2.o fs/vfs.o fs/devfs.o cpu/spinlock.o random.o libc/string/strcmp.o crypto/ChaCha20/chacha20.o crypto/SHA1/sha1.o fs/tmpfs.o libc/string/isequal.o drivers/pst.o halts.o scalls/ppoll.o scalls/ftruncate.o kubsan.o scalls/mmap.o drivers/serial.o scalls/accept.o scalls/bind.o scalls/socket.o socket.o poll.o fs/fifo.o hashmap/hashmap.o fs/shm.o scalls/shm.o elf.o ksbrk.o sched/scheduler.o scalls/stat.o libc/string/copy.o libc/string/strncpy.o drivers/mouse.o libc/string/strlcpy.o libc/string/strcat.o drivers/vbe.o scalls/msleep.o scalls/uptime.o scalls/mkdir.o drivers/pci.o drivers/rtl8139.o network/ethernet.o network/arp.o network/bytes.o network/ipv4.o network/udp.o scalls/recvfrom.o math.o scalls/sendto.o signal.o scalls/kill.o scalls/sigaction.o network/tcp.o drivers/ahci.o crypto/xoshiro256plusplus/xoshiro256plusplus.o
-CFLAGS = -O3 -fsanitize=vla-bound,shift-exponent,pointer-overflow,shift,signed-integer-overflow,bounds -ggdb -ffreestanding -Wall -Werror -mgeneral-regs-only -Wimplicit-fallthrough -I./libc/include/ -I. -Wno-pointer-sign
+OBJ = arch/i386/boot.o init/kernel.o cpu/gdt.o cpu/reload_gdt.o cpu/idt.o cpu/io.o libc/stdio/print.o drivers/keyboard.o log.o drivers/pit.o libc/string/memcpy.o libc/string/strlen.o libc/string/memcmp.o drivers/ata.o libc/string/memset.o cpu/syscall.o  read_eip.o libc/exit/assert.o process.o cpu/int_syscall.o libc/string/strcpy.o arch/i386/mmu.o kmalloc.o fs/ext2.o fs/vfs.o fs/devfs.o cpu/spinlock.o random.o libc/string/strcmp.o crypto/ChaCha20/chacha20.o crypto/SHA1/sha1.o fs/tmpfs.o libc/string/isequal.o drivers/pst.o halts.o scalls/ppoll.o scalls/ftruncate.o kubsan.o scalls/mmap.o drivers/serial.o scalls/accept.o scalls/bind.o scalls/socket.o socket.o poll.o fs/fifo.o hashmap/hashmap.o fs/shm.o scalls/shm.o elf.o ksbrk.o sched/scheduler.o scalls/stat.o libc/string/copy.o libc/string/strncpy.o drivers/mouse.o libc/string/strlcpy.o libc/string/strcat.o drivers/vbe.o scalls/msleep.o scalls/uptime.o scalls/mkdir.o drivers/pci.o drivers/rtl8139.o network/ethernet.o network/arp.o network/bytes.o network/ipv4.o network/udp.o scalls/recvfrom.o math.o scalls/sendto.o signal.o scalls/kill.o scalls/sigaction.o network/tcp.o drivers/ahci.o crypto/xoshiro256plusplus/xoshiro256plusplus.o scalls/chdir.o
+CFLAGS = -O0 -fsanitize=vla-bound,shift-exponent,pointer-overflow,shift,signed-integer-overflow,bounds -ggdb -ffreestanding -Wall -Werror -mgeneral-regs-only -Wimplicit-fallthrough -I./libc/include/ -I. -Wno-pointer-sign
 INCLUDE=-I./includes/ -I./libc/include/
 
 all: myos.iso
diff --git a/kernel/cpu/syscall.c b/kernel/cpu/syscall.c
index 024d06f..31fa055 100644
--- a/kernel/cpu/syscall.c
+++ b/kernel/cpu/syscall.c
@@ -9,6 +9,7 @@
 #include <kmalloc.h>
 #include <scalls/accept.h>
 #include <scalls/bind.h>
+#include <scalls/chdir.h>
 #include <scalls/ftruncate.h>
 #include <scalls/kill.h>
 #include <scalls/mkdir.h>
@@ -22,8 +23,8 @@
 #include <scalls/socket.h>
 #include <scalls/stat.h>
 #include <scalls/uptime.h>
-#include <typedefs.h>
 #include <string.h>
+#include <typedefs.h>
 
 #pragma GCC diagnostic ignored "-Wpedantic"
 
@@ -167,11 +168,11 @@ void (*syscall_functions[])() = {
     (void(*))syscall_msleep,    (void(*))syscall_uptime,
     (void(*))syscall_mkdir,     (void(*))syscall_recvfrom,
     (void(*))syscall_sendto,    (void(*))syscall_kill,
-    (void(*))syscall_sigaction,
+    (void(*))syscall_sigaction, (void(*))syscall_chdir,
 };
 
-void syscall_function_handler(u32 eax, u32 arg1, u32 arg2,
-                              u32 arg3, u32 arg4, u32 arg5) {
+void syscall_function_handler(u32 eax, u32 arg1, u32 arg2, u32 arg3, u32 arg4,
+                              u32 arg5) {
   assert(eax < sizeof(syscall_functions) / sizeof(syscall_functions[0]));
   syscall_functions[eax](arg1, arg2, arg3, arg4, arg5);
 }
diff --git a/kernel/fs/vfs.c b/kernel/fs/vfs.c
index 0911c95..8c9e08d 100644
--- a/kernel/fs/vfs.c
+++ b/kernel/fs/vfs.c
@@ -168,6 +168,27 @@ int vfs_fstat(int fd, struct stat *buf) {
   return fd_ptr->inode->stat(fd_ptr, buf);
 }
 
+int vfs_chdir(const char *path) {
+  char tmp_path[256];
+  char *resolved_path = vfs_resolve_path(path, tmp_path);
+  {
+    int tmp_fd = vfs_open(resolved_path, O_READ, 0);
+    if (0 > tmp_fd)
+      return tmp_fd;
+    struct stat stat_result;
+    vfs_fstat(tmp_fd, &stat_result);
+    if (STAT_DIR != stat_result.st_mode) {
+      kprintf("vfs_chdir: -ENOTDIR\n");
+      return -ENOTDIR;
+    }
+    vfs_close(tmp_fd);
+  }
+  strcpy(get_current_task()->current_working_directory, resolved_path);
+  if ('/' != resolved_path[strlen(resolved_path)])
+    strcat(get_current_task()->current_working_directory, "/");
+  return 0;
+}
+
 int vfs_mkdir(const char *path, int mode) {
   vfs_mounts_t *file_mount = 0;
   int length = 0;
diff --git a/kernel/fs/vfs.h b/kernel/fs/vfs.h
index 3e3e1ff..b6a3401 100644
--- a/kernel/fs/vfs.h
+++ b/kernel/fs/vfs.h
@@ -79,7 +79,7 @@ void vfs_mount(char *path, vfs_inode_t *local_root);
 int vfs_pwrite(int fd, void *buf, u64 count, u64 offset);
 int raw_vfs_pwrite(vfs_fd_t *vfs_fd, void *buf, u64 count, u64 offset);
 int raw_vfs_pread(vfs_fd_t *vfs_fd, void *buf, u64 count, u64 offset);
-int vfs_pread(int fd, void *buf, u32 count, u32 offset);
+int vfs_pread(int fd, void *buf, u64 count, u64 offset);
 vfs_vm_object_t *vfs_get_vm_object(int fd, u64 length, u64 offset);
 int vfs_dup2(int org_fd, int new_fd);
 vfs_inode_t *vfs_internal_open(const char *file);
diff --git a/kernel/scalls/chdir.c b/kernel/scalls/chdir.c
new file mode 100644
index 0000000..ec6ba92
--- /dev/null
+++ b/kernel/scalls/chdir.c
@@ -0,0 +1,6 @@
+#include <fs/vfs.h>
+#include <scalls/chdir.h>
+
+int syscall_chdir(const char *path) {
+  return vfs_chdir(path);
+}
diff --git a/kernel/scalls/chdir.h b/kernel/scalls/chdir.h
new file mode 100644
index 0000000..574ca0d
--- /dev/null
+++ b/kernel/scalls/chdir.h
@@ -0,0 +1 @@
+int syscall_chdir(const char *path);
diff --git a/kernel/sched/scheduler.c b/kernel/sched/scheduler.c
index e81320b..7d13277 100644
--- a/kernel/sched/scheduler.c
+++ b/kernel/sched/scheduler.c
@@ -54,7 +54,11 @@ process_t *create_process(process_t *p) {
                       r->cr3);
   r->signal_handler_stack = 0x80000000;
 
-  strcpy(r->current_working_directory, "/");
+  if (p) {
+    strcpy(r->current_working_directory, p->current_working_directory);
+  } else {
+    strcpy(r->current_working_directory, "/");
+  }
   r->data_segment_end = (p) ? p->data_segment_end : NULL;
   memset((void *)r->halts, 0, 2 * sizeof(u32));
   for (int i = 0; i < 100; i++) {