/*
* namei.c --- ext2fs directory lookup operations
*
- * Copyright (C) 1993, 1994 Theodore Ts'o. This file may be
- * redistributed under the terms of the GNU Public License.
+ * 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>
-#include <stdlib.h>
-#include <linux/fs.h>
+#endif
+
+/* #define NAMEI_DEBUG */
+
#include <linux/ext2_fs.h>
#include "ext2fs.h"
-struct dir_context {
- ino_t dir;
- int flags;
- char *buf;
- int (*func)(struct ext2_dir_entry *dirent,
- int offset,
- int blocksize,
- char *buf,
- void *private);
- void *private;
- errcode_t errcode;
-};
-
-static int process_dir_block(ext2_filsys fs,
- blk_t *blocknr,
- int blockcnt,
- void *private);
-
-errcode_t ext2fs_dir_iterate(ext2_filsys fs,
- ino_t dir,
- int flags,
- char *block_buf,
- int (*func)(struct ext2_dir_entry *dirent,
- int offset,
- int blocksize,
- char *buf,
- void *private),
- void *private)
+static errcode_t open_namei(ext2_filsys fs, ino_t root, ino_t base,
+ const char *pathname, size_t pathlen, int follow,
+ int link_count, char *buf, ino_t *res_inode);
+
+static errcode_t follow_link(ext2_filsys fs, ino_t root, ino_t dir,
+ ino_t inode, int link_count,
+ char *buf, ino_t *res_inode)
{
- struct dir_context ctx;
- errcode_t retval;
+ 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);
- retval = ext2fs_check_directory(fs, dir);
- if (retval)
- return retval;
-
- ctx.dir = dir;
- ctx.flags = flags;
- if (block_buf)
- ctx.buf = block_buf;
- else {
- ctx.buf = malloc(fs->blocksize);
- if (!ctx.buf)
- return ENOMEM;
+#endif
+ retval = ext2fs_read_inode (fs, inode, &ei);
+ if (retval) return retval;
+ if (!LINUX_S_ISLNK (ei.i_mode)) {
+ *res_inode = inode;
+ return 0;
}
- ctx.func = func;
- ctx.private = private;
- ctx.errcode = 0;
- retval = ext2fs_block_iterate(fs, dir, 0, 0, process_dir_block, &ctx);
- if (!block_buf)
- free(ctx.buf);
- if (retval)
- return retval;
- return ctx.errcode;
+ 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;
}
-static int process_dir_block(ext2_filsys fs,
- blk_t *blocknr,
- int blockcnt,
- void *private)
+/*
+ * 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, ino_t root, ino_t dir,
+ const char *pathname, int pathlen,
+ int link_count, char *buf,
+ const char **name, int *namelen, ino_t *res_inode)
{
- struct dir_context *ctx = (struct dir_context *) private;
- int offset = 0;
- int ret;
- int changed = 0;
- int do_abort = 0;
- struct ext2_dir_entry *dirent;
-
- if (blockcnt < 0)
- return 0;
-
- ctx->errcode = io_channel_read_blk(fs->io, *blocknr, 1, ctx->buf);
- if (ctx->errcode)
- return BLOCK_ABORT;
-
- while (offset < fs->blocksize) {
- dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
- if (!dirent->inode &&
- !(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
- goto next;
-
- ret = (ctx->func)(dirent, offset, fs->blocksize,
- ctx->buf, ctx->private);
- if (ret & DIRENT_CHANGED)
- changed++;
- if (ret & DIRENT_ABORT) {
- do_abort++;
- break;
- }
-next:
- if (((offset + dirent->rec_len) > fs->blocksize) ||
- (dirent->rec_len < 8) ||
- ((dirent->name_len+8) > dirent->rec_len)) {
- ctx->errcode = EXT2_ET_DIR_CORRUPTED;
- return BLOCK_ABORT;
- }
- offset += dirent->rec_len;
+ char c;
+ const char *thisname;
+ int len;
+ 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;
+}
- if (changed) {
- ctx->errcode = io_channel_write_blk(fs->io, *blocknr, 1,
- ctx->buf);
- if (ctx->errcode)
- return BLOCK_ABORT;
+static errcode_t open_namei(ext2_filsys fs, ino_t root, ino_t base,
+ const char *pathname, size_t pathlen, int follow,
+ int link_count, char *buf, ino_t *res_inode)
+{
+ const char *basename;
+ int namelen;
+ 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;
}
- if (do_abort)
- return BLOCK_ABORT;
+ 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;
}
-struct lookup_struct {
- const char *name;
- int len;
- ino_t *inode;
- int found;
-};
-
-static int lookup_proc(struct ext2_dir_entry *dirent,
- int offset,
- int blocksize,
- char *buf,
- void *private)
+errcode_t ext2fs_namei(ext2_filsys fs, ino_t root, ino_t cwd,
+ const char *name, ino_t *inode)
{
- struct lookup_struct *ls = (struct lookup_struct *) private;
+ char *buf;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
- if (ls->len != dirent->name_len)
- return 0;
- if (strncmp(ls->name, dirent->name, dirent->name_len))
- return 0;
- *ls->inode = dirent->inode;
- ls->found++;
- return DIRENT_ABORT;
-}
+ 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_lookup(ext2_filsys fs, ino_t dir, const char *name,
- int namelen, char *buf, ino_t *inode)
+errcode_t ext2fs_namei_follow(ext2_filsys fs, ino_t root, ino_t cwd,
+ const char *name, ino_t *inode)
{
- errcode_t retval;
- struct lookup_struct ls;
-
- ls.name = name;
- ls.len = namelen;
- ls.inode = inode;
- ls.found = 0;
+ char *buf;
+ errcode_t retval;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
- retval = ext2fs_dir_iterate(fs, dir, 0, buf, lookup_proc, &ls);
+ 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);
- return (ls.found) ? 0 : ENOENT;
+ ext2fs_free_mem((void **) &buf);
+ return retval;
}
-errcode_t ext2fs_namei(ext2_filsys fs, ino_t root, ino_t cwd, const char *name,
- ino_t *inode)
+extern errcode_t ext2fs_follow_link(ext2_filsys fs, ino_t root, ino_t cwd,
+ ino_t inode, ino_t *res_inode)
{
- ino_t dir = cwd;
- char *buf;
- const char *p = name, *q;
- int len;
- errcode_t retval;
-
- buf = malloc(fs->blocksize);
- if (!buf)
- return ENOMEM;
- if (*p == '/') {
- p++;
- dir = root;
- }
- while (*p) {
- q = strchr(p, '/');
- if (q)
- len = q - p;
- else
- len = strlen(p);
- if (len) {
- retval = ext2fs_lookup(fs, dir, p, len, buf, &dir);
- if (retval) {
- free(buf);
- return retval;
- }
- }
- if (q)
- p = q+1;
- else
- break;
- }
- *inode = dir;
- free(buf);
- return 0;
+ 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;
}
+
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff