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-rw-r--r--e2fslib/namei.c205
1 files changed, 205 insertions, 0 deletions
diff --git a/e2fslib/namei.c b/e2fslib/namei.c
new file mode 100644
index 0000000..18be0f1
--- /dev/null
+++ b/e2fslib/namei.c
@@ -0,0 +1,205 @@
+/*
+ * namei.c --- ext2fs directory lookup operations
+ *
+ * Copyright (C) 1993, 1994, 1994, 1995 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+/* #define NAMEI_DEBUG */
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,
+ const char *pathname, size_t pathlen, int follow,
+ int link_count, char *buf, ext2_ino_t *res_inode);
+
+static errcode_t follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,
+ ext2_ino_t inode, int link_count,
+ char *buf, ext2_ino_t *res_inode)
+{
+ char *pathname;
+ char *buffer = 0;
+ errcode_t retval;
+ struct ext2_inode ei;
+
+#ifdef NAMEI_DEBUG
+ printf("follow_link: root=%lu, dir=%lu, inode=%lu, lc=%d\n",
+ root, dir, inode, link_count);
+
+#endif
+ retval = ext2fs_read_inode (fs, inode, &ei);
+ if (retval) return retval;
+ if (!LINUX_S_ISLNK (ei.i_mode)) {
+ *res_inode = inode;
+ return 0;
+ }
+ if (link_count++ > 5) {
+ return EXT2_ET_SYMLINK_LOOP;
+ }
+ if (ei.i_blocks) {
+ retval = ext2fs_get_mem(fs->blocksize, (void **) &buffer);
+ if (retval)
+ return retval;
+ retval = io_channel_read_blk(fs->io, ei.i_block[0], 1, buffer);
+ if (retval) {
+ ext2fs_free_mem((void **) &buffer);
+ return retval;
+ }
+ pathname = buffer;
+ } else
+ pathname = (char *)&(ei.i_block[0]);
+ retval = open_namei(fs, root, dir, pathname, ei.i_size, 1,
+ link_count, buf, res_inode);
+ if (buffer)
+ ext2fs_free_mem((void **) &buffer);
+ return retval;
+}
+
+/*
+ * This routine interprets a pathname in the context of the current
+ * directory and the root directory, and returns the inode of the
+ * containing directory, and a pointer to the filename of the file
+ * (pointing into the pathname) and the length of the filename.
+ */
+static errcode_t dir_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,
+ const char *pathname, int pathlen,
+ int link_count, char *buf,
+ const char **name, int *namelen,
+ ext2_ino_t *res_inode)
+{
+ char c;
+ const char *thisname;
+ int len;
+ ext2_ino_t inode;
+ errcode_t retval;
+
+ if ((c = *pathname) == '/') {
+ dir = root;
+ pathname++;
+ pathlen--;
+ }
+ while (1) {
+ thisname = pathname;
+ for (len=0; --pathlen >= 0;len++) {
+ c = *(pathname++);
+ if (c == '/')
+ break;
+ }
+ if (pathlen < 0)
+ break;
+ retval = ext2fs_lookup (fs, dir, thisname, len, buf, &inode);
+ if (retval) return retval;
+ retval = follow_link (fs, root, dir, inode,
+ link_count, buf, &dir);
+ if (retval) return retval;
+ }
+ *name = thisname;
+ *namelen = len;
+ *res_inode = dir;
+ return 0;
+}
+
+static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,
+ const char *pathname, size_t pathlen, int follow,
+ int link_count, char *buf, ext2_ino_t *res_inode)
+{
+ const char *basename;
+ int namelen;
+ ext2_ino_t dir, inode;
+ errcode_t retval;
+
+#ifdef NAMEI_DEBUG
+ printf("open_namei: root=%lu, dir=%lu, path=%*s, lc=%d\n",
+ root, base, pathlen, pathname, link_count);
+#endif
+ retval = dir_namei(fs, root, base, pathname, pathlen,
+ link_count, buf, &basename, &namelen, &dir);
+ if (retval) return retval;
+ if (!namelen) { /* special case: '/usr/' etc */
+ *res_inode=dir;
+ return 0;
+ }
+ retval = ext2fs_lookup (fs, dir, basename, namelen, buf, &inode);
+ if (retval)
+ return retval;
+ if (follow) {
+ retval = follow_link(fs, root, dir, inode, link_count,
+ buf, &inode);
+ if (retval)
+ return retval;
+ }
+#ifdef NAMEI_DEBUG
+ printf("open_namei: (link_count=%d) returns %lu\n",
+ link_count, inode);
+#endif
+ *res_inode = inode;
+ return 0;
+}
+
+errcode_t ext2fs_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
+ const char *name, ext2_ino_t *inode)
+{
+ char *buf;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
+ if (retval)
+ return retval;
+
+ retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0,
+ buf, inode);
+
+ ext2fs_free_mem((void **) &buf);
+ return retval;
+}
+
+errcode_t ext2fs_namei_follow(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
+ const char *name, ext2_ino_t *inode)
+{
+ char *buf;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
+ if (retval)
+ return retval;
+
+ retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0,
+ buf, inode);
+
+ ext2fs_free_mem((void **) &buf);
+ return retval;
+}
+
+errcode_t ext2fs_follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,
+ ext2_ino_t inode, ext2_ino_t *res_inode)
+{
+ char *buf;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
+ if (retval)
+ return retval;
+
+ retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode);
+
+ ext2fs_free_mem((void **) &buf);
+ return retval;
+}
+