update name of code to labcodes

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

@@ -0,0 +1,126 @@
+#include <defs.h>
+#include <string.h>
+#include <vfs.h>
+#include <inode.h>
+#include <iobuf.h>
+#include <stat.h>
+#include <proc.h>
+#include <error.h>
+#include <assert.h>
+
+/*
+ * get_cwd_nolock - retrieve current process's working directory. without lock protect
+ */
+static struct inode *
+get_cwd_nolock(void) {
+    return current->filesp->pwd;
+}
+/*
+ * set_cwd_nolock - set current working directory.
+ */
+static void
+set_cwd_nolock(struct inode *pwd) {
+    current->filesp->pwd = pwd;
+}
+
+/*
+ * lock_cfs - lock the fs related process on current process 
+ */
+static void
+lock_cfs(void) {
+    lock_files(current->filesp);
+}
+/*
+ * unlock_cfs - unlock the fs related process on current process 
+ */
+static void
+unlock_cfs(void) {
+    unlock_files(current->filesp);
+}
+
+/*
+ *  vfs_get_curdir - Get current directory as a inode.
+ */
+int
+vfs_get_curdir(struct inode **dir_store) {
+    struct inode *node;
+    if ((node = get_cwd_nolock()) != NULL) {
+        vop_ref_inc(node);
+        *dir_store = node;
+        return 0;
+    }
+    return -E_NOENT;
+}
+
+/*
+ * vfs_set_curdir - Set current directory as a inode.
+ *                  The passed inode must in fact be a directory.
+ */
+int
+vfs_set_curdir(struct inode *dir) {
+    int ret = 0;
+    lock_cfs();
+    struct inode *old_dir;
+    if ((old_dir = get_cwd_nolock()) != dir) {
+        if (dir != NULL) {
+            uint32_t type;
+            if ((ret = vop_gettype(dir, &type)) != 0) {
+                goto out;
+            }
+            if (!S_ISDIR(type)) {
+                ret = -E_NOTDIR;
+                goto out;
+            }
+            vop_ref_inc(dir);
+        }
+        set_cwd_nolock(dir);
+        if (old_dir != NULL) {
+            vop_ref_dec(old_dir);
+        }
+    }
+out:
+    unlock_cfs();
+    return ret;
+}
+
+/*
+ * vfs_chdir - Set current directory, as a pathname. Use vfs_lookup to translate
+ *             it to a inode.
+ */
+int
+vfs_chdir(char *path) {
+    int ret;
+    struct inode *node;
+    if ((ret = vfs_lookup(path, &node)) == 0) {
+        ret = vfs_set_curdir(node);
+        vop_ref_dec(node);
+    }
+    return ret;
+}
+/*
+ * vfs_getcwd - retrieve current working directory(cwd).
+ */
+int
+vfs_getcwd(struct iobuf *iob) {
+    int ret;
+    struct inode *node;
+    if ((ret = vfs_get_curdir(&node)) != 0) {
+        return ret;
+    }
+    assert(node->in_fs != NULL);
+
+    const char *devname = vfs_get_devname(node->in_fs);
+    if ((ret = iobuf_move(iob, (char *)devname, strlen(devname), 1, NULL)) != 0) {
+        goto out;
+    }
+    char colon = ':';
+    if ((ret = iobuf_move(iob, &colon, sizeof(colon), 1, NULL)) != 0) {
+        goto out;
+    }
+    ret = vop_namefile(node, iob);
+
+out:
+    vop_ref_dec(node);
+    return ret;
+}
+