diff options
Diffstat (limited to 'lib/ext2fs/namei.c')
| -rw-r--r-- | lib/ext2fs/namei.c | 207 |
1 files changed, 176 insertions, 31 deletions
diff --git a/lib/ext2fs/namei.c b/lib/ext2fs/namei.c index 496c7266..8fc71b08 100644 --- a/lib/ext2fs/namei.c +++ b/lib/ext2fs/namei.c @@ -13,6 +13,8 @@ #include <errno.h> #endif +/* #define NAMEI_DEBUG */ + #include <linux/ext2_fs.h> #include "ext2fs.h" @@ -173,43 +175,186 @@ errcode_t ext2fs_lookup(ext2_filsys fs, ino_t dir, const char *name, return (ls.found) ? 0 : ENOENT; } -errcode_t ext2fs_namei(ext2_filsys fs, ino_t root, ino_t cwd, const char *name, - ino_t *inode) + +static errcode_t open_namei(ext2_filsys fs, ino_t root, ino_t base, + const char *pathname, int 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) { - ino_t dir = cwd; - char *buf; - const char *p = name, *q; - int len; - errcode_t retval; + char *pathname; + char *buffer = 0; + errcode_t retval; + struct ext2_inode ei; - EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); +#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 ENOMEM; + 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; +} - buf = malloc(fs->blocksize); - if (!buf) - return ENOMEM; - if (*p == '/') { - p++; - dir = root; +/* + * 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 (*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; - } + while (1) { + thisname = pathname; + for (len=0; --pathlen >= 0;len++) { + c = *(pathname++); + if (c == '/') + break; } - if (q) - p = q+1; - else + 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, int 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; } - *inode = dir; - free(buf); + 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 ENOMEM; + + 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 ENOMEM; + + 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 ENOMEM; + + retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode); + + free(buf); + return retval; +} + |