/*
* dir_iterate.c --- ext2fs directory iteration operations
*
* Copyright (C) 1993, 1994, 1994, 1995, 1996, 1997 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 <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include "ext2_fs.h"
#include "ext2fsP.h"
#define EXT4_MAX_REC_LEN ((1<<16)-1)
errcode_t ext2fs_get_rec_len(ext2_filsys fs,
struct ext2_dir_entry *dirent,
unsigned int *rec_len)
{
unsigned int len = dirent->rec_len;
if (fs->blocksize < 65536)
*rec_len = len;
else if (len == EXT4_MAX_REC_LEN || len == 0)
*rec_len = fs->blocksize;
else
*rec_len = (len & 65532) | ((len & 3) << 16);
return 0;
}
errcode_t ext2fs_set_rec_len(ext2_filsys fs,
unsigned int len,
struct ext2_dir_entry *dirent)
{
if ((len > fs->blocksize) || (fs->blocksize > (1 << 18)) || (len & 3))
return EINVAL;
if (len < 65536) {
dirent->rec_len = len;
return 0;
}
if (len == fs->blocksize) {
if (fs->blocksize == 65536)
dirent->rec_len = EXT4_MAX_REC_LEN;
else
dirent->rec_len = 0;
} else
dirent->rec_len = (len & 65532) | ((len >> 16) & 3);
return 0;
}
/*
* This function checks to see whether or not a potential deleted
* directory entry looks valid. What we do is check the deleted entry
* and each successive entry to make sure that they all look valid and
* that the last deleted entry ends at the beginning of the next
* undeleted entry. Returns 1 if the deleted entry looks valid, zero
* if not valid.
*/
static int ext2fs_validate_entry(ext2_filsys fs, char *buf,
unsigned int offset,
unsigned int final_offset)
{
struct ext2_dir_entry *dirent;
unsigned int rec_len;
#define DIRENT_MIN_LENGTH 12
while ((offset < final_offset) &&
(offset <= fs->blocksize - DIRENT_MIN_LENGTH)) {
dirent = (struct ext2_dir_entry *)(buf + offset);
if (ext2fs_get_rec_len(fs, dirent, &rec_len))
return 0;
offset += rec_len;
if ((rec_len < 8) ||
((rec_len % 4) != 0) ||
((((unsigned) dirent->name_len & 0xFF)+8) > rec_len))
return 0;
}
return (offset == final_offset);
}
errcode_t ext2fs_dir_iterate2(ext2_filsys fs,
ext2_ino_t dir,
int flags,
char *block_buf,
int (*func)(ext2_ino_t dir,
int entry,
struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *priv_data),
void *priv_data)
{
struct dir_context ctx;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
retval = ext2fs_check_directory(fs, dir);
if (retval)
return retval;
ctx.dir = dir;
ctx.flags = flags;
if (block_buf)
ctx.buf = block_buf;
else {
retval = ext2fs_get_mem(fs->blocksize, &ctx.buf);
if (retval)
return retval;
}
ctx.func = func;
ctx.priv_data = priv_data;
ctx.errcode = 0;
retval = ext2fs_block_iterate3(fs, dir, BLOCK_FLAG_READ_ONLY, 0,
ext2fs_process_dir_block, &ctx);
if (!block_buf)
ext2fs_free_mem(&ctx.buf);
if (retval)
return retval;
return ctx.errcode;
}
struct xlate {
int (*func)(struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *priv_data);
void *real_private;
};
static int xlate_func(ext2_ino_t dir EXT2FS_ATTR((unused)),
int entry EXT2FS_ATTR((unused)),
struct ext2_dir_entry *dirent, int offset,
int blocksize, char *buf, void *priv_data)
{
struct xlate *xl = (struct xlate *) priv_data;
return (*xl->func)(dirent, offset, blocksize, buf, xl->real_private);
}
errcode_t ext2fs_dir_iterate(ext2_filsys fs,
ext2_ino_t dir,
int flags,
char *block_buf,
int (*func)(struct ext2_dir_entry *dirent,
int offset,
int blocksize,
char *buf,
void *priv_data),
void *priv_data)
{
struct xlate xl;
xl.real_private = priv_data;
xl.func = func;
return ext2fs_dir_iterate2(fs, dir, flags, block_buf,
xlate_func, &xl);
}
/*
* Helper function which is private to this module. Used by
* ext2fs_dir_iterate() and ext2fs_dblist_dir_iterate()
*/
int ext2fs_process_dir_block(ext2_filsys fs,
blk64_t *blocknr,
e2_blkcnt_t blockcnt,
blk64_t ref_block EXT2FS_ATTR((unused)),
int ref_offset EXT2FS_ATTR((unused)),
void *priv_data)
{
struct dir_context *ctx = (struct dir_context *) priv_data;
unsigned int offset = 0;
unsigned int next_real_entry = 0;
int ret = 0;
int changed = 0;
int do_abort = 0;
unsigned int rec_len, size;
int entry;
struct ext2_dir_entry *dirent;
if (blockcnt < 0)
return 0;
entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
ctx->errcode = ext2fs_read_dir_block3(fs, *blocknr, ctx->buf, 0);
if (ctx->errcode)
return BLOCK_ABORT;
while (offset < fs->blocksize) {
dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
if (ext2fs_get_rec_len(fs, dirent, &rec_len))
return BLOCK_ABORT;
if (((offset + rec_len) > fs->blocksize) ||
(rec_len < 8) ||
((rec_len % 4) != 0) ||
((((unsigned) dirent->name_len & 0xFF)+8) > rec_len)) {
ctx->errcode = EXT2_ET_DIR_CORRUPTED;
return BLOCK_ABORT;
}
if (!dirent->inode &&
!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
goto next;
ret = (ctx->func)(ctx->dir,
(next_real_entry > offset) ?
DIRENT_DELETED_FILE : entry,
dirent, offset,
fs->blocksize, ctx->buf,
ctx->priv_data);
if (entry < DIRENT_OTHER_FILE)
entry++;
if (ret & DIRENT_CHANGED) {
if (ext2fs_get_rec_len(fs, dirent, &rec_len))
return BLOCK_ABORT;
changed++;
}
if (ret & DIRENT_ABORT) {
do_abort++;
break;
}
next:
if (next_real_entry == offset)
next_real_entry += rec_len;
if (ctx->flags & DIRENT_FLAG_INCLUDE_REMOVED) {
size = ((dirent->name_len & 0xFF) + 11) & ~3;
if (rec_len != size) {
unsigned int final_offset;
final_offset = offset + rec_len;
offset += size;
while (offset < final_offset &&
!ext2fs_validate_entry(fs, ctx->buf,
offset,
final_offset))
offset += 4;
continue;
}
}
offset += rec_len;
}
if (changed) {
ctx->errcode = ext2fs_write_dir_block3(fs, *blocknr, ctx->buf,
0);
if (ctx->errcode)
return BLOCK_ABORT;
}
if (do_abort)
return BLOCK_ABORT;
return 0;
}