feat: refine symbolic link support.

[lunaix-os.git] / lunaix-os / kernel / fs / vfs.c

diff --git a/lunaix-os/kernel/fs/vfs.c b/lunaix-os/kernel/fs/vfs.c
index cc751b60e3537990f20c12358fd2123917dbd21b..7959fc3ffc3cce0cc58d79ec40ec777666480e5f 100644 (file)
--- a/lunaix-os/kernel/fs/vfs.c
+++ b/lunaix-os/kernel/fs/vfs.c
@@ -44,7 +44,6 @@
 */
 
 #include <klibc/string.h>
-#include <lunaix/dirent.h>
 #include <lunaix/foptions.h>
 #include <lunaix/fs.h>
 #include <lunaix/mm/cake.h>
@@ -53,9 +52,12 @@
 #include <lunaix/process.h>
 #include <lunaix/spike.h>
 #include <lunaix/syscall.h>
+#include <lunaix/syscall_utils.h>
 
 #include <lunaix/fs/twifs.h>
 
+#include <sys/dirent_defs.h>
+
 static struct cake_pile* dnode_pile;
 static struct cake_pile* inode_pile;
 static struct cake_pile* file_pile;
@@ -266,11 +268,11 @@ vfs_pclose(struct v_file* file, pid_t pid)
         atomic_fetch_sub(&file->dnode->ref_count, 1);
         file->inode->open_count--;
 
-        // Prevent dead lock.
-        // This happened when process is terminated while blocking on read.
-        // In that case, the process is still holding the inode lock and it will
-        // never get released.
         /*
+         * Prevent dead lock.
+         * This happened when process is terminated while blocking on read.
+         * In that case, the process is still holding the inode lock and it
+             will never get released.
          * The unlocking should also include ownership check.
          *
          * To see why, consider two process both open the same file both with
@@ -500,7 +502,12 @@ vfs_i_free(struct v_inode* inode)
         pcache_release(inode->pg_cache);
         vfree(inode->pg_cache);
     }
-    inode->ops->sync(inode);
+    // we don't need to sync inode.
+    // If an inode can be free, then it must be properly closed.
+    // Hence it must be synced already!
+    if (inode->destruct) {
+        inode->destruct(inode);
+    }
     hlist_delete(&inode->hash_list);
     cake_release(inode_pile, inode);
 }
@@ -508,6 +515,7 @@ vfs_i_free(struct v_inode* inode)
 /* ---- System call definition and support ---- */
 
 #define FLOCATE_CREATE_EMPTY 1
+#define FLOCATE_CREATE_ONLY 2
 
 int
 vfs_getfd(int fd, struct v_fd** fd_s)
@@ -534,7 +542,13 @@ __vfs_try_locate_file(const char* path,
     }
 
     errno = vfs_walk(*fdir, name.value, file, NULL, 0);
-    if (errno != ENOENT || !(options & FLOCATE_CREATE_EMPTY)) {
+
+    if (errno != ENOENT && (options & FLOCATE_CREATE_ONLY)) {
+        return EEXIST;
+    }
+
+    if (errno != ENOENT ||
+        !(options & (FLOCATE_CREATE_EMPTY | FLOCATE_CREATE_ONLY))) {
         return errno;
     }
 
@@ -564,18 +578,17 @@ vfs_do_open(const char* path, int options)
 {
     int errno, fd;
     struct v_dnode *dentry, *file;
-    struct v_file* ofile = 0;
+    struct v_file* ofile = NULL;
 
     errno = __vfs_try_locate_file(
       path, &dentry, &file, (options & FO_CREATE) ? FLOCATE_CREATE_EMPTY : 0);
 
-    if (errno || (errno = vfs_open(file, &ofile))) {
-        return errno;
-    }
+    if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
 
-    struct v_inode* o_inode = ofile->inode;
+        if (errno || (errno = vfs_open(file, &ofile))) {
+            return errno;
+        }
 
-    if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
         struct v_fd* fd_s = cake_grab(fd_pile);
         memset(fd_s, 0, sizeof(*fd_s));
 
@@ -620,13 +633,13 @@ __vfs_readdir_callback(struct dir_context* dctx,
                        const int len,
                        const int dtype)
 {
-    struct dirent* dent = (struct dirent*)dctx->cb_data;
+    struct lx_dirent* dent = (struct lx_dirent*)dctx->cb_data;
     strncpy(dent->d_name, name, DIRENT_NAME_MAX_LEN);
     dent->d_nlen = len;
     dent->d_type = dtype;
 }
 
-__DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent)
+__DEFINE_LXSYSCALL2(int, sys_readdir, int, fd, struct lx_dirent*, dent)
 {
     struct v_fd* fd_s;
     int errno;
@@ -1195,30 +1208,37 @@ __DEFINE_LXSYSCALL2(int,
                     link_target)
 {
     int errno;
-    struct v_dnode* dnode;
-    if ((errno = vfs_walk_proc(pathname, &dnode, NULL, 0))) {
+    struct v_dnode *dnode, *file;
+    if ((errno = __vfs_try_locate_file(
+           pathname, &dnode, &file, FLOCATE_CREATE_ONLY))) {
         goto done;
     }
 
-    if (errno = vfs_check_writable(dnode)) {
+    if (errno = vfs_check_writable(file)) {
         goto done;
     }
 
-    if (!dnode->inode->ops->set_symlink) {
+    if (!file->inode->ops->set_symlink) {
         errno = ENOTSUP;
         goto done;
     }
 
-    lock_inode(dnode->inode);
+    lock_inode(file->inode);
 
-    errno = dnode->inode->ops->set_symlink(dnode->inode, link_target);
+    errno = file->inode->ops->set_symlink(file->inode, link_target);
 
-    unlock_inode(dnode->inode);
+    unlock_inode(file->inode);
 
 done:
     return DO_STATUS(errno);
 }
 
+void
+vfs_ref_file(struct v_file* file)
+{
+    atomic_fetch_add(&file->ref_count, 1);
+}
+
 void
 vfs_ref_dnode(struct v_dnode* dnode)
 {
@@ -1310,7 +1330,7 @@ __DEFINE_LXSYSCALL2(char*, getcwd, char*, buf, size_t, size)
         }
     }
 
-    buf[len + 1] = '\0';
+    buf[len] = '\0';
 
     ret_ptr = buf;