Add chdir (working) and getcwd (stub)

include/sys/syscall.h

@@ -5,6 +5,8 @@
 #define SYSCALL_NR_OPEN     2
 #define SYSCALL_NR_CLOSE    3
 #define SYSCALL_NR_STAT     4
+#define SYSCALL_NR_GETCWD   79
+#define SYSCALL_NR_CHDIR    80
 #define SYSCALL_NR_READDIR  89
 
 #define SYSCALL_NR_BRK      12

sys/amd64/syscall.c

@@ -19,6 +19,8 @@ static ssize_t sys_write(int fd, const void *buf, size_t lim);
 static ssize_t sys_readdir(int fd, struct dirent *ent);
 static int sys_open(const char *filename, int flags, int mode);
 static void sys_close(int fd);
+static int sys_getcwd(char *buf, size_t lim);
+static int sys_chdir(const char *path);
 static int sys_stat(const char *filename, struct stat *st);
 static void sys_exit(int status);
 static int sys_kill(int pid, int signum);
@@ -50,6 +52,10 @@ intptr_t amd64_syscall(uintptr_t rdi, uintptr_t rsi, uintptr_t rdx, uintptr_t rc
         return sys_execve((const char *) rdi, NULL, NULL);
     case SYSCALL_NR_READDIR:
         return sys_readdir((int) rdi, (struct dirent *) rsi);
+    case SYSCALL_NR_GETCWD:
+        return sys_getcwd((char *) rdi, (size_t) rsi);
+    case SYSCALL_NR_CHDIR:
+        return sys_chdir((const char *) rdi);
 
     case SYSCALL_NRX_SIGNAL:
         sys_signal(rdi);
@@ -137,6 +143,31 @@ static ssize_t sys_readdir(int fd, struct dirent *ent) {
     return src->d_reclen;
 }
 
+static int sys_chdir(const char *filename) {
+    struct thread *thr = get_cpu()->thread;
+    _assert(thr);
+    _assert(filename);
+
+    return vfs_chdir(&thr->ioctx, filename);
+}
+
+// Kinda incompatible with linux, but who cares as long as it's
+// POSIX on the libc side
+static int sys_getcwd(char *buf, size_t lim) {
+    struct thread *thr = get_cpu()->thread;
+    _assert(thr);
+    _assert(buf);
+
+    // TODO: actually implement this
+    if (lim < 4) {
+        return -1;
+    }
+
+    strcpy(buf, "???");
+
+    return 0;
+}
+
 static int sys_open(const char *filename, int flags, int mode) {
     struct thread *thr = get_cpu()->thread;
     _assert(thr);

sys/vfs/node.c

@@ -101,9 +101,6 @@ void vnode_unref(vnode_t *vn) {
         return;
     }
 
-    // TODO: don't free root nodes
-    char buf[1024];
-    vfs_vnode_path(buf, vn);
     struct vfs_node *node = (struct vfs_node *) vn->tree_node;
     if (!node->parent) {
         return;
@@ -117,7 +114,6 @@ void vnode_unref(vnode_t *vn) {
                 return;
             }
 
-            kdebug("free %s\n", buf);
             // Free vnode
             vnode_free(vn);
         }

sys/vfs/vfs.c

@@ -378,22 +378,6 @@ static int vfs_find(vnode_t *cwd_vnode, const char *path, vnode_t **res_vnode) {
     }
 }
 
-static void vfs_dump_node(struct vfs_node *node, int o) {
-    // TODO: node dumpinh
-}
-
-void vfs_dump_tree(void) {
-    if (!vfs_root_node.vnode) {
-        return;
-    }
-    vfs_dump_node(&vfs_root_node, 0);
-}
-
-void vfs_vnode_path(char *path, vnode_t *vn) {
-    // TODO: path printing
-    path[0] = 0;
-}
-
 int vfs_mount_internal(struct vfs_node *at, void *blkdev, const char *fs_name, const char *opt) {
     struct fs_class *fs_class;
 

usr/init.c

@@ -75,8 +75,26 @@ static int cmd_exec(const char *cmd) {
         return 0;
     }
 
-    if (!strcmp(cmd, "ls") || !strncmp(cmd, "ls ", 3)) {
+    if (!strcmp(cmd, "cd") || !strncmp(cmd, "cd ", 3)) {
         const char *path = cmd[2] ? cmd + 3 : "/";
+        int res = chdir(path);
+
+        if (res < 0) {
+            perror(path);
+        }
+        return res;
+    }
+
+    if (!strcmp(cmd, "pwd")) {
+        char buf[512];
+        if (getcwd(buf, sizeof(buf))) {
+            puts(buf);
+        }
+        return 0;
+    }
+
+    if (!strcmp(cmd, "ls") || !strncmp(cmd, "ls ", 3)) {
+        const char *path = cmd[2] ? cmd + 3 : ".";
         DIR *dir;
         struct dirent *ent;
 

usr/libc/include/bits/syscall.h

@@ -17,5 +17,7 @@ int kill(int pid, int signum);
 void __kernel_signal(uintptr_t handler);
 __attribute__((noreturn)) void __kernel_sigret(void);
 int getpid(void);
+int chdir(const char *filename);
+char *getcwd(char *buf, size_t size);
 
 __attribute__((noreturn)) void exit(int code);

usr/libc/syscall.c

@@ -113,6 +113,18 @@ int getpid(void) {
     return ASM_SYSCALL0(SYSCALL_NR_GETPID);
 }
 
+int chdir(const char *filename) {
+    return SET_ERRNO(int, ASM_SYSCALL1(SYSCALL_NR_CHDIR, filename));
+}
+
+char *getcwd(char *buf, size_t lim) {
+    if (SET_ERRNO(int, ASM_SYSCALL2(SYSCALL_NR_GETCWD, buf, lim)) == 0) {
+        return buf;
+    } else {
+        return NULL;
+    }
+}
+
 // Although sbrk() is implemented in userspace, I guess it should also be here
 void *sbrk(intptr_t inc) {
     if (inc == 0) {