mirror of https://github.com/vitalif/e2fsprogs
216 lines
4.1 KiB
C
216 lines
4.1 KiB
C
/*
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* namei.c --- ext2fs directory lookup operations
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*
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* Copyright (C) 1993, 1994 Theodore Ts'o. This file may be
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* redistributed under the terms of the GNU Public License.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#if HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include <linux/ext2_fs.h>
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#include "ext2fs.h"
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struct dir_context {
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ino_t dir;
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int flags;
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char *buf;
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int (*func)(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *private);
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void *private;
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errcode_t errcode;
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};
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static int process_dir_block(ext2_filsys fs,
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blk_t *blocknr,
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int blockcnt,
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void *private);
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errcode_t ext2fs_dir_iterate(ext2_filsys fs,
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ino_t dir,
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int flags,
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char *block_buf,
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int (*func)(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *private),
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void *private)
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{
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struct dir_context ctx;
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errcode_t retval;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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retval = ext2fs_check_directory(fs, dir);
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if (retval)
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return retval;
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ctx.dir = dir;
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ctx.flags = flags;
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if (block_buf)
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ctx.buf = block_buf;
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else {
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ctx.buf = malloc(fs->blocksize);
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if (!ctx.buf)
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return ENOMEM;
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}
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ctx.func = func;
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ctx.private = private;
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ctx.errcode = 0;
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retval = ext2fs_block_iterate(fs, dir, 0, 0, process_dir_block, &ctx);
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if (!block_buf)
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free(ctx.buf);
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if (retval)
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return retval;
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return ctx.errcode;
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}
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static int process_dir_block(ext2_filsys fs,
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blk_t *blocknr,
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int blockcnt,
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void *private)
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{
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struct dir_context *ctx = (struct dir_context *) private;
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int offset = 0;
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int ret;
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int changed = 0;
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int do_abort = 0;
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struct ext2_dir_entry *dirent;
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if (blockcnt < 0)
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return 0;
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ctx->errcode = ext2fs_read_dir_block(fs, *blocknr, ctx->buf);
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if (ctx->errcode)
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return BLOCK_ABORT;
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while (offset < fs->blocksize) {
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dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
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if (!dirent->inode &&
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!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
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goto next;
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ret = (ctx->func)(dirent, offset, fs->blocksize,
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ctx->buf, ctx->private);
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if (ret & DIRENT_CHANGED)
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changed++;
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if (ret & DIRENT_ABORT) {
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do_abort++;
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break;
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}
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next:
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if (((offset + dirent->rec_len) > fs->blocksize) ||
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(dirent->rec_len < 8) ||
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((dirent->name_len+8) > dirent->rec_len)) {
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ctx->errcode = EXT2_ET_DIR_CORRUPTED;
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return BLOCK_ABORT;
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}
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offset += dirent->rec_len;
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}
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if (changed) {
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ctx->errcode = ext2fs_write_dir_block(fs, *blocknr, ctx->buf);
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if (ctx->errcode)
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return BLOCK_ABORT;
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}
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if (do_abort)
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return BLOCK_ABORT;
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return 0;
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}
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struct lookup_struct {
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const char *name;
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int len;
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ino_t *inode;
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int found;
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};
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static int lookup_proc(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *private)
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{
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struct lookup_struct *ls = (struct lookup_struct *) private;
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if (ls->len != dirent->name_len)
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return 0;
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if (strncmp(ls->name, dirent->name, dirent->name_len))
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return 0;
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*ls->inode = dirent->inode;
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ls->found++;
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return DIRENT_ABORT;
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}
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errcode_t ext2fs_lookup(ext2_filsys fs, ino_t dir, const char *name,
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int namelen, char *buf, ino_t *inode)
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{
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errcode_t retval;
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struct lookup_struct ls;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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ls.name = name;
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ls.len = namelen;
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ls.inode = inode;
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ls.found = 0;
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retval = ext2fs_dir_iterate(fs, dir, 0, buf, lookup_proc, &ls);
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if (retval)
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return retval;
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return (ls.found) ? 0 : ENOENT;
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}
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errcode_t ext2fs_namei(ext2_filsys fs, ino_t root, ino_t cwd, const char *name,
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ino_t *inode)
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{
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ino_t dir = cwd;
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char *buf;
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const char *p = name, *q;
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int len;
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errcode_t retval;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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buf = malloc(fs->blocksize);
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if (!buf)
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return ENOMEM;
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if (*p == '/') {
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p++;
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dir = root;
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}
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while (*p) {
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q = strchr(p, '/');
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if (q)
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len = q - p;
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else
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len = strlen(p);
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if (len) {
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retval = ext2fs_lookup(fs, dir, p, len, buf, &dir);
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if (retval) {
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free(buf);
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return retval;
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}
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}
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if (q)
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p = q+1;
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else
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break;
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}
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*inode = dir;
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free(buf);
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return 0;
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}
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