"Robert P. J. Day" | 63fc1a9 | 2006-07-02 19:47:05 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 2 | /* |
| 3 | * namei.c --- ext2fs directory lookup operations |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 4 | * |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 5 | * Copyright (C) 1993, 1994, 1994, 1995 Theodore Ts'o. |
| 6 | * |
| 7 | * %Begin-Header% |
| 8 | * This file may be redistributed under the terms of the GNU Public |
| 9 | * License. |
| 10 | * %End-Header% |
| 11 | */ |
| 12 | |
| 13 | #include <stdio.h> |
| 14 | #include <string.h> |
| 15 | #if HAVE_UNISTD_H |
| 16 | #include <unistd.h> |
| 17 | #endif |
| 18 | |
| 19 | /* #define NAMEI_DEBUG */ |
| 20 | |
| 21 | #include "ext2_fs.h" |
| 22 | #include "ext2fs.h" |
| 23 | |
| 24 | static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base, |
| 25 | const char *pathname, size_t pathlen, int follow, |
| 26 | int link_count, char *buf, ext2_ino_t *res_inode); |
| 27 | |
| 28 | static errcode_t follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir, |
| 29 | ext2_ino_t inode, int link_count, |
| 30 | char *buf, ext2_ino_t *res_inode) |
| 31 | { |
| 32 | char *pathname; |
| 33 | char *buffer = 0; |
| 34 | errcode_t retval; |
| 35 | struct ext2_inode ei; |
| 36 | |
| 37 | #ifdef NAMEI_DEBUG |
| 38 | printf("follow_link: root=%lu, dir=%lu, inode=%lu, lc=%d\n", |
| 39 | root, dir, inode, link_count); |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 40 | |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 41 | #endif |
| 42 | retval = ext2fs_read_inode (fs, inode, &ei); |
| 43 | if (retval) return retval; |
| 44 | if (!LINUX_S_ISLNK (ei.i_mode)) { |
| 45 | *res_inode = inode; |
| 46 | return 0; |
| 47 | } |
| 48 | if (link_count++ > 5) { |
| 49 | return EXT2_ET_SYMLINK_LOOP; |
| 50 | } |
| 51 | if (ext2fs_inode_data_blocks(fs,&ei)) { |
| 52 | retval = ext2fs_get_mem(fs->blocksize, &buffer); |
| 53 | if (retval) |
| 54 | return retval; |
| 55 | retval = io_channel_read_blk(fs->io, ei.i_block[0], 1, buffer); |
| 56 | if (retval) { |
| 57 | ext2fs_free_mem(&buffer); |
| 58 | return retval; |
| 59 | } |
| 60 | pathname = buffer; |
| 61 | } else |
| 62 | pathname = (char *)&(ei.i_block[0]); |
| 63 | retval = open_namei(fs, root, dir, pathname, ei.i_size, 1, |
| 64 | link_count, buf, res_inode); |
Rob Landley | e7c43b6 | 2006-03-01 16:39:45 +0000 | [diff] [blame] | 65 | ext2fs_free_mem(&buffer); |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 66 | return retval; |
| 67 | } |
| 68 | |
| 69 | /* |
| 70 | * This routine interprets a pathname in the context of the current |
| 71 | * directory and the root directory, and returns the inode of the |
| 72 | * containing directory, and a pointer to the filename of the file |
| 73 | * (pointing into the pathname) and the length of the filename. |
| 74 | */ |
| 75 | static errcode_t dir_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir, |
| 76 | const char *pathname, int pathlen, |
| 77 | int link_count, char *buf, |
| 78 | const char **name, int *namelen, |
| 79 | ext2_ino_t *res_inode) |
| 80 | { |
| 81 | char c; |
| 82 | const char *thisname; |
| 83 | int len; |
| 84 | ext2_ino_t inode; |
| 85 | errcode_t retval; |
| 86 | |
| 87 | if ((c = *pathname) == '/') { |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 88 | dir = root; |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 89 | pathname++; |
| 90 | pathlen--; |
| 91 | } |
| 92 | while (1) { |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 93 | thisname = pathname; |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 94 | for (len=0; --pathlen >= 0;len++) { |
| 95 | c = *(pathname++); |
| 96 | if (c == '/') |
| 97 | break; |
| 98 | } |
| 99 | if (pathlen < 0) |
| 100 | break; |
| 101 | retval = ext2fs_lookup (fs, dir, thisname, len, buf, &inode); |
| 102 | if (retval) return retval; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 103 | retval = follow_link (fs, root, dir, inode, |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 104 | link_count, buf, &dir); |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 105 | if (retval) return retval; |
| 106 | } |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 107 | *name = thisname; |
| 108 | *namelen = len; |
| 109 | *res_inode = dir; |
| 110 | return 0; |
| 111 | } |
| 112 | |
| 113 | static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base, |
| 114 | const char *pathname, size_t pathlen, int follow, |
| 115 | int link_count, char *buf, ext2_ino_t *res_inode) |
| 116 | { |
| 117 | const char *basename; |
| 118 | int namelen; |
| 119 | ext2_ino_t dir, inode; |
| 120 | errcode_t retval; |
| 121 | |
| 122 | #ifdef NAMEI_DEBUG |
| 123 | printf("open_namei: root=%lu, dir=%lu, path=%*s, lc=%d\n", |
| 124 | root, base, pathlen, pathname, link_count); |
| 125 | #endif |
| 126 | retval = dir_namei(fs, root, base, pathname, pathlen, |
| 127 | link_count, buf, &basename, &namelen, &dir); |
| 128 | if (retval) return retval; |
| 129 | if (!namelen) { /* special case: '/usr/' etc */ |
| 130 | *res_inode=dir; |
| 131 | return 0; |
| 132 | } |
| 133 | retval = ext2fs_lookup (fs, dir, basename, namelen, buf, &inode); |
| 134 | if (retval) |
| 135 | return retval; |
| 136 | if (follow) { |
| 137 | retval = follow_link(fs, root, dir, inode, link_count, |
| 138 | buf, &inode); |
| 139 | if (retval) |
| 140 | return retval; |
| 141 | } |
| 142 | #ifdef NAMEI_DEBUG |
| 143 | printf("open_namei: (link_count=%d) returns %lu\n", |
| 144 | link_count, inode); |
| 145 | #endif |
| 146 | *res_inode = inode; |
| 147 | return 0; |
| 148 | } |
| 149 | |
| 150 | errcode_t ext2fs_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd, |
| 151 | const char *name, ext2_ino_t *inode) |
| 152 | { |
| 153 | char *buf; |
| 154 | errcode_t retval; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 155 | |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 156 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| 157 | |
| 158 | retval = ext2fs_get_mem(fs->blocksize, &buf); |
| 159 | if (retval) |
| 160 | return retval; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 161 | |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 162 | retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0, |
| 163 | buf, inode); |
| 164 | |
| 165 | ext2fs_free_mem(&buf); |
| 166 | return retval; |
| 167 | } |
| 168 | |
| 169 | errcode_t ext2fs_namei_follow(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd, |
| 170 | const char *name, ext2_ino_t *inode) |
| 171 | { |
| 172 | char *buf; |
| 173 | errcode_t retval; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 174 | |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 175 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| 176 | |
| 177 | retval = ext2fs_get_mem(fs->blocksize, &buf); |
| 178 | if (retval) |
| 179 | return retval; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 180 | |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 181 | retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0, |
| 182 | buf, inode); |
| 183 | |
| 184 | ext2fs_free_mem(&buf); |
| 185 | return retval; |
| 186 | } |
| 187 | |
| 188 | errcode_t ext2fs_follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd, |
| 189 | ext2_ino_t inode, ext2_ino_t *res_inode) |
| 190 | { |
| 191 | char *buf; |
| 192 | errcode_t retval; |
Tim Riker | c1ef7bd | 2006-01-25 00:08:53 +0000 | [diff] [blame] | 193 | |
Mike Frysinger | 1fd98e0 | 2005-05-09 22:10:42 +0000 | [diff] [blame] | 194 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| 195 | |
| 196 | retval = ext2fs_get_mem(fs->blocksize, &buf); |
| 197 | if (retval) |
| 198 | return retval; |
| 199 | |
| 200 | retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode); |
| 201 | |
| 202 | ext2fs_free_mem(&buf); |
| 203 | return retval; |
| 204 | } |
| 205 | |