syscalls: hopefully fix chdir syscall breaking sometimes

include/string.h

@@ -11,5 +11,6 @@ size_t strlen(const char*);
 char *strcat(char *dest, const char *src);
 char *strcpy(char *dest, const char *src);
 char *strtok(char *str, const char *delim);
+char *strrchr(const char *s, int c);
 
 #endif

src/tasking/syscalls.c

@@ -442,59 +442,55 @@ int sys_execve(TrapFrame *tf) {
 
 int sys_chdir(TrapFrame *tf)
 {
-    l9660_dir new_cwd;
+    const char* path = (const char*)tf->ebx;
+    size_t path_len = strlen(path);
     l9660_file placeholder_file;
+    l9660_dir target_dir;
 
-    new_cwd = *current->cwd;
+    target_dir = *current->cwd;
+    int status = follow_path(path, &placeholder_file, &target_dir);
 
-    int status = follow_path((char*)tf->ebx, &placeholder_file, &new_cwd);
+    // Case 1: The path does not end with a slash (e.g., "/path/to/dir" or "/path/to/file")
+    if (path_len == 0 || path[path_len - 1] != '/') {
+        // If follow_path succeeded, it means the path was a file, which is an error for chdir.
+        if (status == L9660_OK) {
+            return -20; // Return -ENOTDIR
+        }
 
-    if(status == L9660_OK)
-    {
-        *(current->cwd) = new_cwd;
+        // If it failed with L9660_ENOTFILE, it means we found a directory when expecting a file.
+        // This is the expected outcome for a directory path.
+        if (status == L9660_ENOTFILE) {
+            // The safe way to proceed is to re-traverse the path with a trailing slash.
+            // This avoids using the potentially corrupt 'target_dir' left by the failed call.
+            char new_path[path_len + 2];
+            memcpy(new_path, path, path_len);
+            new_path[path_len] = '/';
+            new_path[path_len + 1] = '\0';
+
+            // Reset target_dir and try again with the corrected path.
+            target_dir = *current->cwd;
+            status = follow_path(new_path, &placeholder_file, &target_dir);
+        }
     }
 
-    if(status == L9660_ENOTFILE)
-    {
-        l9660_dir dir1;
-        l9660_status err = l9660_opendirat(&dir1, &new_cwd, (char*)tf->ebx);
-        if(err != L9660_ENOTDIR)
-        {
-            *(current->cwd) = dir1;
-            return 0;
-        }
+    // At this point, 'status' should be L9660_OK if the path was a valid directory.
+    if (status == L9660_OK) {
+        *current->cwd = target_dir;
+        return 0;
     }
 
     switch(status)
     {
         case L9660_EIO:
-            return -5;//-EIO
-            break;
         case L9660_EBADFS:
-            return -5;//EIO as well
-            break;
+            return -5;  // -EIO
         case L9660_ENOENT:
-            return -2;
-            break;
+            return -2;  // -ENOENT
         case L9660_ENOTDIR:
-            return -20;//ENOTDIR
-            break;
-        case L9660_OK:
-            return 0;
-            break;
+            return -20; // -ENOTDIR
         default:
-            return -5;//EIO
-            break;
+            return -1;  // Generic error
     }
-
-    //strcat(current->cwd->fat->path, "/");
-    //strcat(current->cwd->fat->path, (char*)tf->ebx);
-
-    int result = 0;//fat_opendir(current->cwd, (const char*)tf->ebx);
-    if(result == 0)
-        return 0;
-
-    return -1;
 }
 
 #include "../include/vfs.h"

src/utils/string.c

@@ -149,4 +149,15 @@ char *strtok(char *str, const char *delim) {
     }
     
     return token_start;
+}
+
+char *strrchr(const char *s, int c) {
+    const char *p = NULL;
+
+    for (;;) {
+        if (*s == (char)c)
+            p = s;
+        if (*s++ == '\0')
+            return (char *)p;
+    }
 }