diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/ext2fs/namei.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/lib/ext2fs/namei.c b/lib/ext2fs/namei.c new file mode 100644 index 0000000..1064ab5 --- /dev/null +++ b/lib/ext2fs/namei.c @@ -0,0 +1,227 @@ +/* + * 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 Library + * General Public License, version 2. + * %End-Header% + */ + +#include "config.h" +#include <stdio.h> +#include <string.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif + +/* #define NAMEI_DEBUG */ + +#include "ext2_fs.h" +#include "ext2fs.h" +#include "ext2fsP.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; + blk64_t blk; + +#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++ >= EXT2FS_MAX_NESTED_LINKS) + return EXT2_ET_SYMLINK_LOOP; + + if (ext2fs_is_fast_symlink(&ei)) + pathname = (char *)&(ei.i_block[0]); + else if (ei.i_flags & EXT4_INLINE_DATA_FL) { + retval = ext2fs_get_memzero(ei.i_size, &buffer); + if (retval) + return retval; + + retval = ext2fs_inline_data_get(fs, inode, + &ei, buffer, NULL); + if (retval) { + ext2fs_free_mem(&buffer); + return retval; + } + pathname = buffer; + } else { + retval = ext2fs_bmap2(fs, inode, &ei, NULL, 0, 0, NULL, &blk); + if (retval) + return retval; + + retval = ext2fs_get_mem(fs->blocksize, &buffer); + if (retval) + return retval; + + retval = io_channel_read_blk64(fs->io, blk, 1, buffer); + if (retval) { + ext2fs_free_mem(&buffer); + return retval; + } + pathname = buffer; + } + + retval = open_namei(fs, root, dir, pathname, ei.i_size, 1, + link_count, buf, res_inode); + if (buffer) + ext2fs_free_mem(&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 *base_name; + 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, &base_name, &namelen, &dir); + if (retval) return retval; + if (!namelen) { /* special case: '/usr/' etc */ + *res_inode=dir; + return 0; + } + retval = ext2fs_lookup (fs, dir, base_name, 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, &buf); + if (retval) + return retval; + + retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0, + buf, inode); + + ext2fs_free_mem(&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, &buf); + if (retval) + return retval; + + retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0, + buf, inode); + + ext2fs_free_mem(&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, &buf); + if (retval) + return retval; + + retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode); + + ext2fs_free_mem(&buf); + return retval; +} + |