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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:49:25 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:49:25 +0000 |
commit | 464df1d5e5ab1322e2dd0a7796939fff1aeefa9a (patch) | |
tree | 6a403684e0978f0287d7f0ec0e5aab1fd31a59e1 /lib/ext2fs/link.c | |
parent | Initial commit. (diff) | |
download | e2fsprogs-upstream/1.47.0.tar.xz e2fsprogs-upstream/1.47.0.zip |
Adding upstream version 1.47.0.upstream/1.47.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/ext2fs/link.c | 646 |
1 files changed, 646 insertions, 0 deletions
diff --git a/lib/ext2fs/link.c b/lib/ext2fs/link.c new file mode 100644 index 0000000..d69b1e3 --- /dev/null +++ b/lib/ext2fs/link.c @@ -0,0 +1,646 @@ +/* + * link.c --- create links in a ext2fs directory + * + * Copyright (C) 1993, 1994 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 + +#include "ext2_fs.h" +#include "ext2fs.h" +#include "ext2fsP.h" + +#define EXT2_DX_ROOT_OFF 24 + +struct dx_frame { + void *buf; + blk64_t pblock; + struct ext2_dx_countlimit *head; + struct ext2_dx_entry *entries; + struct ext2_dx_entry *at; +}; + +struct dx_lookup_info { + const char *name; + int namelen; + int hash_alg; + __u32 hash; + unsigned levels; + struct dx_frame frames[EXT4_HTREE_LEVEL]; +}; + +static errcode_t alloc_dx_frame(ext2_filsys fs, struct dx_frame *frame) +{ + return ext2fs_get_mem(fs->blocksize, &frame->buf); +} + +static void dx_release(struct dx_lookup_info *info) +{ + unsigned level; + + for (level = 0; level < info->levels; level++) { + if (info->frames[level].buf == NULL) + break; + ext2fs_free_mem(&(info->frames[level].buf)); + } + info->levels = 0; +} + +static void dx_search_entry(struct dx_frame *frame, int count, __u32 hash) +{ + struct ext2_dx_entry *p, *q, *m; + + p = frame->entries + 1; + q = frame->entries + count - 1; + while (p <= q) { + m = p + (q - p) / 2; + if (ext2fs_le32_to_cpu(m->hash) > hash) + q = m - 1; + else + p = m + 1; + } + frame->at = p - 1; +} + +static errcode_t load_logical_dir_block(ext2_filsys fs, ext2_ino_t dir, + struct ext2_inode *diri, blk64_t block, + blk64_t *pblk, void *buf) +{ + errcode_t errcode; + int ret_flags; + + errcode = ext2fs_bmap2(fs, dir, diri, NULL, 0, block, &ret_flags, + pblk); + if (errcode) + return errcode; + if (ret_flags & BMAP_RET_UNINIT) + return EXT2_ET_DIR_CORRUPTED; + return ext2fs_read_dir_block4(fs, *pblk, buf, 0, dir); +} + +static errcode_t dx_lookup(ext2_filsys fs, ext2_ino_t dir, + struct ext2_inode *diri, struct dx_lookup_info *info) +{ + struct ext2_dx_root_info *root; + errcode_t errcode; + int level = 0; + int count, limit; + int hash_alg; + int hash_flags = diri->i_flags & EXT4_CASEFOLD_FL; + __u32 minor_hash; + struct dx_frame *frame; + + errcode = alloc_dx_frame(fs, &(info->frames[0])); + if (errcode) + return errcode; + info->levels = 1; + + errcode = load_logical_dir_block(fs, dir, diri, 0, + &(info->frames[0].pblock), + info->frames[0].buf); + if (errcode) + goto out_err; + root = (struct ext2_dx_root_info *) ((char *)info->frames[0].buf + + EXT2_DX_ROOT_OFF); + hash_alg = root->hash_version; + if (hash_alg != EXT2_HASH_TEA && hash_alg != EXT2_HASH_HALF_MD4 && + hash_alg != EXT2_HASH_LEGACY) { + errcode = EXT2_ET_DIRHASH_UNSUPP; + goto out_err; + } + if (hash_alg <= EXT2_HASH_TEA && + fs->super->s_flags & EXT2_FLAGS_UNSIGNED_HASH) + hash_alg += 3; + if (root->indirect_levels >= ext2_dir_htree_level(fs)) { + errcode = EXT2_ET_DIR_CORRUPTED; + goto out_err; + } + info->hash_alg = hash_alg; + + errcode = ext2fs_dirhash2(hash_alg, info->name, info->namelen, + fs->encoding, hash_flags, + fs->super->s_hash_seed, &info->hash, + &minor_hash); + if (errcode) + goto out_err; + + for (level = 0; level <= root->indirect_levels; level++) { + frame = &(info->frames[level]); + if (level > 0) { + errcode = alloc_dx_frame(fs, frame); + if (errcode) + goto out_err; + info->levels++; + + errcode = load_logical_dir_block(fs, dir, diri, + ext2fs_le32_to_cpu(info->frames[level-1].at->block) & 0x0fffffff, + &(frame->pblock), frame->buf); + if (errcode) + goto out_err; + } + errcode = ext2fs_get_dx_countlimit(fs, frame->buf, + &(frame->head), NULL); + if (errcode) + goto out_err; + count = ext2fs_le16_to_cpu(frame->head->count); + limit = ext2fs_le16_to_cpu(frame->head->limit); + frame->entries = (struct ext2_dx_entry *)(frame->head); + if (!count || count > limit) { + errcode = EXT2_ET_DIR_CORRUPTED; + goto out_err; + } + + dx_search_entry(frame, count, info->hash); + } + return 0; +out_err: + dx_release(info); + return errcode; +} + +struct link_struct { + ext2_filsys fs; + const char *name; + int namelen; + ext2_ino_t inode; + int flags; + int done; + unsigned int blocksize; + errcode_t err; + struct ext2_super_block *sb; +}; + +static int link_proc(ext2_ino_t dir EXT2FS_ATTR((unused)), + int entru EXT2FS_ATTR((unused)), + struct ext2_dir_entry *dirent, + int offset, + int blocksize, + char *buf, + void *priv_data) +{ + struct link_struct *ls = (struct link_struct *) priv_data; + struct ext2_dir_entry *next; + unsigned int rec_len, min_rec_len, curr_rec_len; + int ret = 0; + int csum_size = 0; + + if (ls->done) + return DIRENT_ABORT; + + rec_len = EXT2_DIR_REC_LEN(ls->namelen); + + ls->err = ext2fs_get_rec_len(ls->fs, dirent, &curr_rec_len); + if (ls->err) + return DIRENT_ABORT; + + if (ext2fs_has_feature_metadata_csum(ls->fs->super)) + csum_size = sizeof(struct ext2_dir_entry_tail); + /* + * See if the following directory entry (if any) is unused; + * if so, absorb it into this one. + */ + next = (struct ext2_dir_entry *) (buf + offset + curr_rec_len); + if ((offset + (int) curr_rec_len < blocksize - (8 + csum_size)) && + (next->inode == 0) && + (offset + (int) curr_rec_len + (int) next->rec_len <= blocksize)) { + curr_rec_len += next->rec_len; + ls->err = ext2fs_set_rec_len(ls->fs, curr_rec_len, dirent); + if (ls->err) + return DIRENT_ABORT; + ret = DIRENT_CHANGED; + } + + /* + * If the directory entry is used, see if we can split the + * directory entry to make room for the new name. If so, + * truncate it and return. + */ + if (dirent->inode) { + min_rec_len = EXT2_DIR_REC_LEN(ext2fs_dirent_name_len(dirent)); + if (curr_rec_len < (min_rec_len + rec_len)) + return ret; + rec_len = curr_rec_len - min_rec_len; + ls->err = ext2fs_set_rec_len(ls->fs, min_rec_len, dirent); + if (ls->err) + return DIRENT_ABORT; + next = (struct ext2_dir_entry *) (buf + offset + + dirent->rec_len); + next->inode = 0; + ext2fs_dirent_set_name_len(next, 0); + ext2fs_dirent_set_file_type(next, 0); + ls->err = ext2fs_set_rec_len(ls->fs, rec_len, next); + if (ls->err) + return DIRENT_ABORT; + return DIRENT_CHANGED; + } + + /* + * If we get this far, then the directory entry is not used. + * See if we can fit the request entry in. If so, do it. + */ + if (curr_rec_len < rec_len) + return ret; + dirent->inode = ls->inode; + ext2fs_dirent_set_name_len(dirent, ls->namelen); + strncpy(dirent->name, ls->name, ls->namelen); + if (ext2fs_has_feature_filetype(ls->sb)) + ext2fs_dirent_set_file_type(dirent, ls->flags & 0x7); + + ls->done++; + return DIRENT_ABORT|DIRENT_CHANGED; +} + +static errcode_t add_dirent_to_buf(ext2_filsys fs, e2_blkcnt_t blockcnt, + char *buf, ext2_ino_t dir, + struct ext2_inode *diri, const char *name, + ext2_ino_t ino, int flags, blk64_t *pblkp) +{ + struct dir_context ctx; + struct link_struct ls; + errcode_t retval; + + retval = load_logical_dir_block(fs, dir, diri, blockcnt, pblkp, buf); + if (retval) + return retval; + ctx.errcode = 0; + ctx.func = link_proc; + ctx.dir = dir; + ctx.flags = DIRENT_FLAG_INCLUDE_EMPTY; + ctx.buf = buf; + ctx.priv_data = &ls; + + ls.fs = fs; + ls.name = name; + ls.namelen = strlen(name); + ls.inode = ino; + ls.flags = flags; + ls.done = 0; + ls.sb = fs->super; + ls.blocksize = fs->blocksize; + ls.err = 0; + + ext2fs_process_dir_block(fs, pblkp, blockcnt, 0, 0, &ctx); + if (ctx.errcode) + return ctx.errcode; + if (ls.err) + return ls.err; + if (!ls.done) + return EXT2_ET_DIR_NO_SPACE; + return 0; +} + +struct dx_hash_map { + __u32 hash; + int size; + int off; +}; + +static EXT2_QSORT_TYPE dx_hash_map_cmp(const void *ap, const void *bp) +{ + const struct dx_hash_map *a = ap, *b = bp; + + if (a->hash < b->hash) + return -1; + if (a->hash > b->hash) + return 1; + return 0; +} + +static errcode_t dx_move_dirents(ext2_filsys fs, struct dx_hash_map *map, + int count, void *from, void *to) +{ + struct ext2_dir_entry *de; + int i; + int rec_len = 0; + errcode_t retval; + int csum_size = 0; + void *base = to; + + if (ext2fs_has_feature_metadata_csum(fs->super)) + csum_size = sizeof(struct ext2_dir_entry_tail); + + for (i = 0; i < count; i++) { + de = (struct ext2_dir_entry *) ((char *)from + map[i].off); + rec_len = EXT2_DIR_REC_LEN(ext2fs_dirent_name_len(de)); + memcpy(to, de, rec_len); + retval = ext2fs_set_rec_len(fs, rec_len, to); + if (retval) + return retval; + to = (char *)to + rec_len; + } + /* + * Update rec_len of the last dir entry to stretch to the end of block + */ + to = (char *)to - rec_len; + rec_len = fs->blocksize - ((char *)to - (char *)base) - csum_size; + retval = ext2fs_set_rec_len(fs, rec_len, to); + if (retval) + return retval; + if (csum_size) + ext2fs_initialize_dirent_tail(fs, + EXT2_DIRENT_TAIL(base, fs->blocksize)); + return 0; +} + +static errcode_t dx_insert_entry(ext2_filsys fs, ext2_ino_t dir, + struct dx_lookup_info *info, int level, + __u32 hash, blk64_t lblk) +{ + int pcount; + struct ext2_dx_entry *top, *new; + + pcount = ext2fs_le16_to_cpu(info->frames[level].head->count); + top = info->frames[level].entries + pcount; + new = info->frames[level].at + 1; + memmove(new + 1, new, (char *)top - (char *)new); + new->hash = ext2fs_cpu_to_le32(hash); + new->block = ext2fs_cpu_to_le32(lblk); + info->frames[level].head->count = ext2fs_cpu_to_le16(pcount + 1); + return ext2fs_write_dir_block4(fs, info->frames[level].pblock, + info->frames[level].buf, 0, dir); +} + +static errcode_t dx_split_leaf(ext2_filsys fs, ext2_ino_t dir, + struct ext2_inode *diri, + struct dx_lookup_info *info, void *buf, + blk64_t leaf_pblk, blk64_t new_lblk, + blk64_t new_pblk) +{ + int hash_flags = diri->i_flags & EXT4_CASEFOLD_FL; + struct ext2_dir_entry *de; + void *buf2; + errcode_t retval = 0; + unsigned int rec_len; + unsigned int offset, move_size; + int i, count = 0; + struct dx_hash_map *map; + int continued; + __u32 minor_hash; + + retval = ext2fs_get_mem(fs->blocksize, &buf2); + if (retval) + return retval; + retval = ext2fs_get_array(fs->blocksize / 12, + sizeof(struct dx_hash_map), &map); + if (retval) { + ext2fs_free_mem(&buf2); + return retval; + } + for (offset = 0; offset < fs->blocksize; offset += rec_len) { + de = (struct ext2_dir_entry *) ((char *)buf + offset); + retval = ext2fs_get_rec_len(fs, de, &rec_len); + if (retval) + goto out; + if (ext2fs_dirent_name_len(de) > 0 && de->inode) { + map[count].off = offset; + map[count].size = rec_len; + retval = ext2fs_dirhash2(info->hash_alg, de->name, + ext2fs_dirent_name_len(de), + fs->encoding, hash_flags, + fs->super->s_hash_seed, + &(map[count].hash), + &minor_hash); + if (retval) + goto out; + count++; + } + } + qsort(map, count, sizeof(struct dx_hash_map), dx_hash_map_cmp); + move_size = 0; + /* Find place to split block */ + for (i = count - 1; i >= 0; i--) { + if (move_size + map[i].size / 2 > fs->blocksize / 2) + break; + move_size += map[i].size; + } + /* Let i be the first entry to move */ + i++; + /* Move selected directory entries to new block */ + retval = dx_move_dirents(fs, map + i, count - i, buf, buf2); + if (retval) + goto out; + retval = ext2fs_write_dir_block4(fs, new_pblk, buf2, 0, dir); + if (retval) + goto out; + /* Repack remaining entries in the old block */ + retval = dx_move_dirents(fs, map, i, buf, buf2); + if (retval) + goto out; + retval = ext2fs_write_dir_block4(fs, leaf_pblk, buf2, 0, dir); + if (retval) + goto out; + /* Update parent node */ + continued = map[i].hash == map[i-1].hash; + retval = dx_insert_entry(fs, dir, info, info->levels - 1, + map[i].hash + continued, new_lblk); +out: + ext2fs_free_mem(&buf2); + ext2fs_free_mem(&map); + return retval; +} + +static errcode_t dx_grow_tree(ext2_filsys fs, ext2_ino_t dir, + struct ext2_inode *diri, + struct dx_lookup_info *info, void *buf, + blk64_t leaf_pblk) +{ + int i; + errcode_t retval; + ext2_off64_t size = EXT2_I_SIZE(diri); + blk64_t lblk, pblk; + struct ext2_dir_entry *de; + struct ext2_dx_countlimit *head; + int csum_size = 0; + int count; + + if (ext2fs_has_feature_metadata_csum(fs->super)) + csum_size = sizeof(struct ext2_dx_tail); + + /* Find level which can accommodate new child */ + for (i = info->levels - 1; i >= 0; i--) + if (ext2fs_le16_to_cpu(info->frames[i].head->count) < + ext2fs_le16_to_cpu(info->frames[i].head->limit)) + break; + /* Need to grow tree depth? */ + if (i < 0 && info->levels >= ext2_dir_htree_level(fs)) + return EXT2_ET_DIR_NO_SPACE; + lblk = size / fs->blocksize; + size += fs->blocksize; + retval = ext2fs_inode_size_set(fs, diri, size); + if (retval) + return retval; + retval = ext2fs_fallocate(fs, + EXT2_FALLOCATE_FORCE_INIT | EXT2_FALLOCATE_ZERO_BLOCKS, + dir, diri, 0, lblk, 1); + if (retval) + return retval; + retval = ext2fs_write_inode(fs, dir, diri); + if (retval) + return retval; + retval = ext2fs_bmap2(fs, dir, diri, NULL, 0, lblk, NULL, &pblk); + if (retval) + return retval; + /* Only leaf addition needed? */ + if (i == (int)info->levels - 1) + return dx_split_leaf(fs, dir, diri, info, buf, leaf_pblk, + lblk, pblk); + + de = buf; + de->inode = 0; + ext2fs_dirent_set_name_len(de, 0); + ext2fs_dirent_set_file_type(de, 0); + retval = ext2fs_set_rec_len(fs, fs->blocksize, de); + if (retval) + return retval; + head = (struct ext2_dx_countlimit *) ((char *)buf + 8); + count = ext2fs_le16_to_cpu(info->frames[i+1].head->count); + /* Growing tree depth? */ + if (i < 0) { + struct ext2_dx_root_info *root; + + memcpy(head, info->frames[0].entries, + count * sizeof(struct ext2_dx_entry)); + head->limit = ext2fs_cpu_to_le16( + (fs->blocksize - (8 + csum_size)) / + sizeof(struct ext2_dx_entry)); + /* head->count gets set by memcpy above to correct value */ + + /* Now update tree root */ + info->frames[0].head->count = ext2fs_cpu_to_le16(1); + info->frames[0].entries[0].block = ext2fs_cpu_to_le32(lblk); + root = (struct ext2_dx_root_info *) + ((char *)info->frames[0].buf + EXT2_DX_ROOT_OFF); + root->indirect_levels++; + } else { + /* Splitting internal node in two */ + int count1 = count / 2; + int count2 = count - count1; + __u32 split_hash = ext2fs_le32_to_cpu(info->frames[i+1].entries[count1].hash); + + memcpy(head, info->frames[i+1].entries + count1, + count2 * sizeof(struct ext2_dx_entry)); + head->count = ext2fs_cpu_to_le16(count2); + head->limit = ext2fs_cpu_to_le16( + (fs->blocksize - (8 + csum_size)) / + sizeof(struct ext2_dx_entry)); + info->frames[i+1].head->count = ext2fs_cpu_to_le16(count1); + + /* Update parent node */ + retval = dx_insert_entry(fs, dir, info, i, split_hash, lblk); + if (retval) + return retval; + + } + /* Writeout split block / updated root */ + retval = ext2fs_write_dir_block4(fs, info->frames[i+1].pblock, + info->frames[i+1].buf, 0, dir); + if (retval) + return retval; + /* Writeout new tree block */ + retval = ext2fs_write_dir_block4(fs, pblk, buf, 0, dir); + if (retval) + return retval; + return 0; +} + +static errcode_t dx_link(ext2_filsys fs, ext2_ino_t dir, + struct ext2_inode *diri, const char *name, + ext2_ino_t ino, int flags) +{ + struct dx_lookup_info dx_info; + errcode_t retval; + void *blockbuf; + unsigned restart = 0; + blk64_t leaf_pblk; + + retval = ext2fs_get_mem(fs->blocksize, &blockbuf); + if (retval) + return retval; + + dx_info.name = name; + dx_info.namelen = strlen(name); +again: + retval = dx_lookup(fs, dir, diri, &dx_info); + if (retval) + goto free_buf; + + retval = add_dirent_to_buf(fs, + ext2fs_le32_to_cpu(dx_info.frames[dx_info.levels-1].at->block) & 0x0fffffff, + blockbuf, dir, diri, name, ino, flags, &leaf_pblk); + /* + * Success or error other than ENOSPC...? We are done. We may need upto + * two tries to add entry. One to split htree node and another to add + * new leaf block. + */ + if (restart >= dx_info.levels || retval != EXT2_ET_DIR_NO_SPACE) + goto free_frames; + retval = dx_grow_tree(fs, dir, diri, &dx_info, blockbuf, leaf_pblk); + if (retval) + goto free_frames; + /* Restart everything now that the tree is larger */ + restart++; + dx_release(&dx_info); + goto again; +free_frames: + dx_release(&dx_info); +free_buf: + ext2fs_free_mem(&blockbuf); + return retval; +} + +/* + * Note: the low 3 bits of the flags field are used as the directory + * entry filetype. + */ +#ifdef __TURBOC__ + #pragma argsused +#endif +errcode_t ext2fs_link(ext2_filsys fs, ext2_ino_t dir, const char *name, + ext2_ino_t ino, int flags) +{ + errcode_t retval; + struct link_struct ls; + struct ext2_inode inode; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + if (!(fs->flags & EXT2_FLAG_RW)) + return EXT2_ET_RO_FILSYS; + + if ((retval = ext2fs_read_inode(fs, dir, &inode)) != 0) + return retval; + + if (inode.i_flags & EXT2_INDEX_FL) + return dx_link(fs, dir, &inode, name, ino, flags); + + ls.fs = fs; + ls.name = name; + ls.namelen = name ? strlen(name) : 0; + ls.inode = ino; + ls.flags = flags; + ls.done = 0; + ls.sb = fs->super; + ls.blocksize = fs->blocksize; + ls.err = 0; + + retval = ext2fs_dir_iterate2(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY, + NULL, link_proc, &ls); + if (retval) + return retval; + if (ls.err) + return ls.err; + + if (!ls.done) + return EXT2_ET_DIR_NO_SPACE; + return 0; +} |