feat: simple device abstraction layer

[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 51ef5c9827f6612313564609f2d47029fa2c4c74..48ec27dc18d06155be990d6926f20b1da413f993 100644 (file)
--- a/lunaix-os/kernel/fs/vfs.c
+++ b/lunaix-os/kernel/fs/vfs.c
@@ -37,6 +37,9 @@ static struct hbucket* dnode_cache;
 
 static int fs_id = 0;
 
+struct hstr vfs_ddot = HSTR("..", 2);
+struct hstr vfs_dot = HSTR(".", 1);
+
 struct v_dnode*
 vfs_d_alloc();
 
@@ -62,6 +65,9 @@ vfs_init()
 
     dnode_cache = vzalloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket));
 
+    hstr_rehash(&vfs_ddot, HSTR_FULL_HASH);
+    hstr_rehash(&vfs_dot, HSTR_FULL_HASH);
+
     // 创建一个根superblock，用来蕴含我们的根目录。
     root_sb = vfs_sb_alloc();
     root_sb->root = vfs_d_alloc();
@@ -204,6 +210,7 @@ vfs_walk(struct v_dnode* start,
 error:
     vfree(dnode->name.value);
     vfs_d_free(dnode);
+    *dentry = NULL;
     return errno;
 }
 
@@ -348,7 +355,9 @@ struct v_dnode*
 vfs_d_alloc()
 {
     struct v_dnode* dnode = cake_grab(dnode_pile);
+    memset(dnode, 0, sizeof(*dnode));
     llist_init_head(&dnode->children);
+    return dnode;
 }
 
 void
@@ -375,14 +384,15 @@ vfs_i_free(struct v_inode* inode)
     cake_release(inode_pile, inode);
 }
 
-__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
+int
+__vfs_do_open(struct v_file** file_out, const char* path, int options)
 {
     char name_str[VFS_NAME_MAXLEN];
     struct hstr name = HSTR(name_str, 0);
     struct v_dnode *dentry, *file;
-    int errno, fd;
+    int errno;
     if ((errno = vfs_walk(NULL, path, &dentry, &name, VFS_WALK_PARENT))) {
-        return -1;
+        return ENOENT;
     }
 
     vfs_walk(dentry, name.value, &file, NULL, 0);
@@ -398,23 +408,36 @@ __DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
         errno = vfs_open(file, &opened_file);
     }
 
+    *file_out = opened_file;
+    return errno;
+}
+
+__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
+{
+    struct v_file* opened_file;
+    int errno = __vfs_do_open(&opened_file, path, options), fd;
+
     __current->k_status = errno;
 
     if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
         struct v_fd* fd_s = vzalloc(sizeof(*fd_s));
         fd_s->file = opened_file;
-        fd_s->pos = file->inode->fsize & -((options & FO_APPEND) == 0);
+        fd_s->pos = opened_file->inode->fsize & -((options & FO_APPEND) != 0);
         __current->fdtable->fds[fd] = fd_s;
+        return fd;
     }
 
     return SYSCALL_ESTATUS(errno);
 }
 
+#define GET_FD(fd, fd_s)                                                       \
+    (fd >= 0 && fd < VFS_MAX_FD && (fd_s = __current->fdtable->fds[fd]))
+
 __DEFINE_LXSYSCALL1(int, close, int, fd)
 {
     struct v_fd* fd_s;
     int errno;
-    if (fd < 0 || fd >= VFS_MAX_FD || !(fd_s = __current->fdtable->fds[fd])) {
+    if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     } else if (!(errno = vfs_close(fd_s->file))) {
         vfree(fd_s);
@@ -442,7 +465,7 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent)
 {
     struct v_fd* fd_s;
     int errno;
-    if (fd < 0 || fd >= VFS_MAX_FD || !(fd_s = __current->fdtable->fds[fd])) {
+    if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     } else if (!(fd_s->file->inode->itype & VFS_INODE_TYPE_DIR)) {
         errno = ENOTDIR;
@@ -470,7 +493,9 @@ __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
         goto done;
     }
 
-    if (!parent->inode->ops.mkdir) {
+    if ((parent->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = ENOTSUP;
+    } else if (!parent->inode->ops.mkdir) {
         errno = ENOTSUP;
     } else if (!(parent->inode->itype & VFS_INODE_TYPE_DIR)) {
         errno = ENOTDIR;
@@ -490,12 +515,67 @@ done:
     return SYSCALL_ESTATUS(errno);
 }
 
-__DEFINE_LXSYSCALL3(size_t, read, int, fd, void*, buf, size_t, count)
+__DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count)
 {
-    // TODO
+    int errno = 0;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_file* file = fd_s->file;
+        file->f_pos = fd_s->pos;
+        if ((errno = file->ops.read(file, buf, count)) >= 0) {
+            fd_s->pos += errno;
+        }
+    }
+
+    __current->k_status = errno;
+    return SYSCALL_ESTATUS(errno);
 }
 
-__DEFINE_LXSYSCALL3(size_t, write, int, fd, void*, buf, size_t, count)
+__DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count)
 {
-    // TODO
+    int errno = 0;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_file* file = fd_s->file;
+        file->f_pos = fd_s->pos;
+        if ((errno = file->ops.write(file, buf, count)) >= 0) {
+            fd_s->pos += errno;
+        }
+    }
+
+    __current->k_status = errno;
+    return SYSCALL_ESTATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options)
+{
+    int errno = 0;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        size_t fpos = fd_s->file->f_pos;
+        switch (options) {
+            case FSEEK_CUR:
+                fpos = (size_t)((int)fd_s->file->f_pos + offset);
+                break;
+            case FSEEK_END:
+                fpos = (size_t)((int)fd_s->file->inode->fsize + offset);
+                break;
+            case FSEEK_SET:
+                fpos = offset;
+                break;
+
+            default:
+                break;
+        }
+        fd_s->pos = fpos;
+    }
+
+    __current->k_status = errno;
+    return SYSCALL_ESTATUS(errno);
 }
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