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-rw-r--r--lib/ext2fs/dir_iterate.c315
1 files changed, 315 insertions, 0 deletions
diff --git a/lib/ext2fs/dir_iterate.c b/lib/ext2fs/dir_iterate.c
new file mode 100644
index 0000000..7798a48
--- /dev/null
+++ b/lib/ext2fs/dir_iterate.c
@@ -0,0 +1,315 @@
+/*
+ * 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);
+
+ if (buflen < 8) {
+ ctx->errcode = EXT2_ET_DIR_CORRUPTED;
+ return BLOCK_ABORT;
+ }
+ 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;
+}
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