update name of code to labcodes

labcodes/lab8/kern/fs/vfs/vfslookup.c

@@ -0,0 +1,101 @@
+#include <defs.h>
+#include <string.h>
+#include <vfs.h>
+#include <inode.h>
+#include <error.h>
+#include <assert.h>
+
+/*
+ * get_device- Common code to pull the device name, if any, off the front of a
+ *             path and choose the inode to begin the name lookup relative to.
+ */
+
+static int
+get_device(char *path, char **subpath, struct inode **node_store) {
+    int i, slash = -1, colon = -1;
+    for (i = 0; path[i] != '\0'; i ++) {
+        if (path[i] == ':') { colon = i; break; }
+        if (path[i] == '/') { slash = i; break; }
+    }
+    if (colon < 0 && slash != 0) {
+        /* *
+         * No colon before a slash, so no device name specified, and the slash isn't leading
+         * or is also absent, so this is a relative path or just a bare filename. Start from
+         * the current directory, and use the whole thing as the subpath.
+         * */
+        *subpath = path;
+        return vfs_get_curdir(node_store);
+    }
+    if (colon > 0) {
+        /* device:path - get root of device's filesystem */
+        path[colon] = '\0';
+
+        /* device:/path - skip slash, treat as device:path */
+        while (path[++ colon] == '/');
+        *subpath = path + colon;
+        return vfs_get_root(path, node_store);
+    }
+
+    /* *
+     * we have either /path or :path
+     * /path is a path relative to the root of the "boot filesystem"
+     * :path is a path relative to the root of the current filesystem
+     * */
+    int ret;
+    if (*path == '/') {
+        if ((ret = vfs_get_bootfs(node_store)) != 0) {
+            return ret;
+        }
+    }
+    else {
+        assert(*path == ':');
+        struct inode *node;
+        if ((ret = vfs_get_curdir(&node)) != 0) {
+            return ret;
+        }
+        /* The current directory may not be a device, so it must have a fs. */
+        assert(node->in_fs != NULL);
+        *node_store = fsop_get_root(node->in_fs);
+        vop_ref_dec(node);
+    }
+
+    /* ///... or :/... */
+    while (*(++ path) == '/');
+    *subpath = path;
+    return 0;
+}
+
+/*
+ * vfs_lookup - get the inode according to the path filename
+ */
+int
+vfs_lookup(char *path, struct inode **node_store) {
+    int ret;
+    struct inode *node;
+    if ((ret = get_device(path, &path, &node)) != 0) {
+        return ret;
+    }
+    if (*path != '\0') {
+        ret = vop_lookup(node, path, node_store);
+        vop_ref_dec(node);
+        return ret;
+    }
+    *node_store = node;
+    return 0;
+}
+
+/*
+ * vfs_lookup_parent - Name-to-vnode translation.
+ *  (In BSD, both of these are subsumed by namei().)
+ */
+int
+vfs_lookup_parent(char *path, struct inode **node_store, char **endp){
+    int ret;
+    struct inode *node;
+    if ((ret = get_device(path, &path, &node)) != 0) {
+        return ret;
+    }
+    *endp = path;
+    *node_store = node;
+    return 0;
+}