312 lines
7.5 KiB
C
312 lines
7.5 KiB
C
/*
|
|
* 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 "config.h"
|
|
#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) ||
|
|
((ext2fs_dirent_name_len(dirent)+8) > (int) 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 == EXT2_ET_INLINE_DATA_CANT_ITERATE) {
|
|
(void) ext2fs_inline_data_dir_iterate(fs, dir, &ctx);
|
|
retval = 0;
|
|
}
|
|
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, buflen;
|
|
int entry;
|
|
struct ext2_dir_entry *dirent;
|
|
int csum_size = 0;
|
|
int inline_data;
|
|
errcode_t retval = 0;
|
|
|
|
if (blockcnt < 0)
|
|
return 0;
|
|
|
|
entry = blockcnt ? DIRENT_OTHER_FILE : DIRENT_DOT_FILE;
|
|
|
|
/* If a dir has inline data, we don't need to read block */
|
|
inline_data = !!(ctx->flags & DIRENT_FLAG_INCLUDE_INLINE_DATA);
|
|
if (!inline_data) {
|
|
ctx->errcode = ext2fs_read_dir_block4(fs, *blocknr, ctx->buf, 0,
|
|
ctx->dir);
|
|
if (ctx->errcode)
|
|
return BLOCK_ABORT;
|
|
/* If we handle a normal dir, we traverse the entire block */
|
|
buflen = fs->blocksize;
|
|
} else {
|
|
buflen = ctx->buflen;
|
|
}
|
|
|
|
if (ext2fs_has_feature_metadata_csum(fs->super))
|
|
csum_size = sizeof(struct ext2_dir_entry_tail);
|
|
|
|
while (offset < buflen - 8) {
|
|
dirent = (struct ext2_dir_entry *) (ctx->buf + offset);
|
|
if (ext2fs_get_rec_len(fs, dirent, &rec_len))
|
|
return BLOCK_ABORT;
|
|
if (((offset + rec_len) > buflen) ||
|
|
(rec_len < 8) ||
|
|
((rec_len % 4) != 0) ||
|
|
((ext2fs_dirent_name_len(dirent)+8) > (int) rec_len)) {
|
|
ctx->errcode = EXT2_ET_DIR_CORRUPTED;
|
|
return BLOCK_ABORT;
|
|
}
|
|
if (!dirent->inode) {
|
|
/*
|
|
* We just need to check metadata_csum when this
|
|
* dir hasn't inline data. That means that 'buflen'
|
|
* should be blocksize.
|
|
*/
|
|
if (!inline_data &&
|
|
(offset == buflen - csum_size) &&
|
|
(dirent->rec_len == csum_size) &&
|
|
(dirent->name_len == EXT2_DIR_NAME_LEN_CSUM)) {
|
|
if (!(ctx->flags & DIRENT_FLAG_INCLUDE_CSUM))
|
|
goto next;
|
|
entry = DIRENT_CHECKSUM;
|
|
} else if (!(ctx->flags & DIRENT_FLAG_INCLUDE_EMPTY))
|
|
goto next;
|
|
}
|
|
|
|
ret = (ctx->func)(ctx->dir,
|
|
(next_real_entry > offset) ?
|
|
DIRENT_DELETED_FILE : entry,
|
|
dirent, offset,
|
|
buflen, 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 = (ext2fs_dirent_name_len(dirent) + 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) {
|
|
if (!inline_data) {
|
|
ctx->errcode = ext2fs_write_dir_block4(fs, *blocknr,
|
|
ctx->buf,
|
|
0, ctx->dir);
|
|
if (ctx->errcode)
|
|
return BLOCK_ABORT;
|
|
} else {
|
|
/*
|
|
* return BLOCK_INLINE_DATA_CHANGED to notify caller
|
|
* that inline data has been changed.
|
|
*/
|
|
retval = BLOCK_INLINE_DATA_CHANGED;
|
|
}
|
|
}
|
|
if (do_abort)
|
|
return retval | BLOCK_ABORT;
|
|
return retval;
|
|
}
|