libext2fs: fix potential divide by zero bug caused by a lxcfs bug

[thirdparty/e2fsprogs.git] / debugfs / icheck.c

/*
 * icheck.c --- given a list of blocks, generate a list of inodes
 *
 * Copyright (C) 1994 Theodore Ts'o.  This file may be redistributed
 * under the terms of the GNU Public License.
 */

#include "config.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <sys/types.h>

#include "debugfs.h"

struct block_info {
	blk64_t		blk;
	ext2_ino_t	ino;
};

struct block_walk_struct {
	struct block_info	*barray;
	e2_blkcnt_t		blocks_left;
	e2_blkcnt_t		num_blocks;
	ext2_ino_t		inode;
};

static int icheck_proc(ext2_filsys fs EXT2FS_ATTR((unused)),
		       blk64_t	*block_nr,
		       e2_blkcnt_t blockcnt EXT2FS_ATTR((unused)),
		       blk64_t ref_block EXT2FS_ATTR((unused)),
		       int ref_offset EXT2FS_ATTR((unused)),
		       void *private)
{
	struct block_walk_struct *bw = (struct block_walk_struct *) private;
	e2_blkcnt_t	i;

	for (i=0; i < bw->num_blocks; i++) {
		if (!bw->barray[i].ino && bw->barray[i].blk == *block_nr) {
			bw->barray[i].ino = bw->inode;
			bw->blocks_left--;
		}
	}
	if (!bw->blocks_left)
		return BLOCK_ABORT;

	return 0;
}

void do_icheck(int argc, ss_argv_t argv, int sci_idx EXT2FS_ATTR((unused)),
	       void *infop EXT2FS_ATTR((unused)))
{
	struct block_walk_struct bw;
	struct block_info	*binfo;
	int			i;
	ext2_inode_scan		scan = 0;
	ext2_ino_t		ino;
	struct ext2_inode	inode;
	errcode_t		retval;
	char			*block_buf;

	if (argc < 2) {
		com_err(argv[0], 0, "Usage: icheck <block number> ...");
		return;
	}
	if (check_fs_open(argv[0]))
		return;

	bw.barray = malloc(sizeof(struct block_info) * argc);
	if (!bw.barray) {
		com_err("icheck", ENOMEM,
			"while allocating inode info array");
		return;
	}
	memset(bw.barray, 0, sizeof(struct block_info) * argc);

	block_buf = malloc(current_fs->blocksize * 3);
	if (!block_buf) {
		com_err("icheck", ENOMEM, "while allocating block buffer");
		goto error_out;
	}

	for (i=1; i < argc; i++) {
		if (strtoblk(argv[0], argv[i], NULL, &bw.barray[i-1].blk))
			goto error_out;
	}

	bw.num_blocks = bw.blocks_left = argc-1;

	retval = ext2fs_open_inode_scan(current_fs, 0, &scan);
	if (retval) {
		com_err("icheck", retval, "while opening inode scan");
		goto error_out;
	}

	do {
		retval = ext2fs_get_next_inode(scan, &ino, &inode);
	} while (retval == EXT2_ET_BAD_BLOCK_IN_INODE_TABLE);
	if (retval) {
		com_err("icheck", retval, "while starting inode scan");
		goto error_out;
	}

	while (ino) {
		blk64_t blk;

		if (!inode.i_links_count)
			goto next;

		bw.inode = ino;

		blk = ext2fs_file_acl_block(current_fs, &inode);
		if (blk) {
			icheck_proc(current_fs, &blk, 0,
				    0, 0, &bw);
			if (bw.blocks_left == 0)
				break;
			ext2fs_file_acl_block_set(current_fs, &inode, blk);
		}

		if (!ext2fs_inode_has_valid_blocks2(current_fs, &inode))
			goto next;
		/*
		 * To handle filesystems touched by 0.3c extfs; can be
		 * removed later.
		 */
		if (inode.i_dtime)
			goto next;

		retval = ext2fs_block_iterate3(current_fs, ino,
					       BLOCK_FLAG_READ_ONLY, block_buf,
					       icheck_proc, &bw);
		if (retval) {
			com_err("icheck", retval,
				"while calling ext2fs_block_iterate");
			goto next;
		}

		if (bw.blocks_left == 0)
			break;

	next:
		do {
			retval = ext2fs_get_next_inode(scan, &ino, &inode);
		} while (retval == EXT2_ET_BAD_BLOCK_IN_INODE_TABLE);
		if (retval) {
			com_err("icheck", retval,
				"while doing inode scan");
			goto error_out;
		}
	}

	printf("Block\tInode number\n");
	for (i=0, binfo = bw.barray; i < bw.num_blocks; i++, binfo++) {
		if (binfo->ino == 0) {
			printf("%llu\t<block not found>\n",
			       (unsigned long long) binfo->blk);
			continue;
		}
		printf("%llu\t%u\n", (unsigned long long) binfo->blk,
		       binfo->ino);
	}

error_out:
	free(bw.barray);
	free(block_buf);
	if (scan)
		ext2fs_close_inode_scan(scan);
	return;
}