| /* |
| * 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 |
| #include <stdlib.h> |
| |
| /* #define NAMEI_DEBUG */ |
| |
| #include <linux/ext2_fs.h> |
| |
| #include "ext2fs.h" |
| |
| 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) |
| { |
| 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) { |
| buffer = malloc (fs->blocksize); |
| if (!buffer) |
| return EXT2_NO_MEMORY; |
| retval = io_channel_read_blk(fs->io, ei.i_block[0], 1, buffer); |
| if (retval) { |
| free(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) |
| free (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, 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) |
| { |
| 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; |
| } |
| |
| 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; |
| } |
| 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, ino_t root, ino_t cwd, |
| const char *name, ino_t *inode) |
| { |
| char *buf; |
| errcode_t retval; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| buf = malloc(fs->blocksize); |
| if (!buf) |
| return EXT2_NO_MEMORY; |
| |
| retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0, |
| buf, inode); |
| |
| free(buf); |
| return retval; |
| } |
| |
| errcode_t ext2fs_namei_follow(ext2_filsys fs, ino_t root, ino_t cwd, |
| const char *name, ino_t *inode) |
| { |
| char *buf; |
| errcode_t retval; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| buf = malloc(fs->blocksize); |
| if (!buf) |
| return EXT2_NO_MEMORY; |
| |
| retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0, |
| buf, inode); |
| |
| free(buf); |
| return retval; |
| } |
| |
| extern errcode_t ext2fs_follow_link(ext2_filsys fs, ino_t root, ino_t cwd, |
| ino_t inode, ino_t *res_inode) |
| { |
| char *buf; |
| errcode_t retval; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| buf = malloc(fs->blocksize); |
| if (!buf) |
| return EXT2_NO_MEMORY; |
| |
| retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode); |
| |
| free(buf); |
| return retval; |
| } |
| |