superblock has a check-hash error, an error message noting the superblock check-hash failure is printed and the mount fails. The administrator then runs fsck to repair the filesystem and when successful, the filesystem can once again be mounted. This approach fails if the filesystem in question is a root filesystem from which you are trying to boot. Here, the loader fails when trying to access the filesystem to get the kernel to boot. So it is necessary to allow the loader to ignore the superblock check-hash error and make a best effort to read the kernel. The filesystem may be suffiently corrupted that the read attempt fails, but there is no harm in trying since the loader makes no attempt to write to the filesystem. Once the kernel is loaded and starts to run, it attempts to mount its root filesystem. Once again, failure means that it breaks to its prompt to ask where to get its root filesystem. Unless you have an alternate root filesystem, you are stuck. Since the root filesystem is initially mounted read-only, it is safe to make an attempt to mount the root filesystem with the failed superblock check-hash. Thus, when asked to mount a root filesystem with a failed superblock check-hash, the kernel prints a warning message that the root filesystem superblock check-hash needs repair, but notes that it is ignoring the error and proceeding. It does mark the filesystem as needing an fsck which prevents it from being enabled for writing until fsck has been run on it. The net effect is that the reboot fails to single user, but at least at that point the administrator has the tools at hand to fix the problem. Reported by: Rick Macklem (rmacklem@) Discussed with: Warner Losh (imp@) Sponsored by: Netflix
236 lines
6.4 KiB
C
236 lines
6.4 KiB
C
/* $OpenBSD: fsirand.c,v 1.9 1997/02/28 00:46:33 millert Exp $ */
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/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Todd C. Miller.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/resource.h>
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#include <ufs/ufs/dinode.h>
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#include <ufs/ffs/fs.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <libufs.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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static void usage(void) __dead2;
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int fsirand(char *);
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static int printonly = 0, force = 0, ignorelabel = 0;
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int
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main(int argc, char *argv[])
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{
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int n, ex = 0;
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struct rlimit rl;
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while ((n = getopt(argc, argv, "bfp")) != -1) {
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switch (n) {
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case 'b':
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ignorelabel++;
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break;
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case 'p':
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printonly++;
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break;
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case 'f':
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force++;
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break;
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default:
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usage();
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}
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}
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if (argc - optind < 1)
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usage();
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srandomdev();
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/* Increase our data size to the max */
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if (getrlimit(RLIMIT_DATA, &rl) == 0) {
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rl.rlim_cur = rl.rlim_max;
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if (setrlimit(RLIMIT_DATA, &rl) < 0)
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warn("can't get resource limit to max data size");
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} else
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warn("can't get resource limit for data size");
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for (n = optind; n < argc; n++) {
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if (argc - optind != 1)
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(void)puts(argv[n]);
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ex += fsirand(argv[n]);
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if (n < argc - 1)
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putchar('\n');
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}
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exit(ex);
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}
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int
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fsirand(char *device)
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{
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struct ufs1_dinode *dp1;
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struct ufs2_dinode *dp2;
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caddr_t inodebuf;
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ssize_t ibufsize;
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struct fs *sblock;
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ino_t inumber;
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ufs2_daddr_t dblk;
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int devfd, n, cg, ret;
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u_int32_t bsize = DEV_BSIZE;
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if ((devfd = open(device, printonly ? O_RDONLY : O_RDWR)) < 0) {
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warn("can't open %s", device);
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return (1);
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}
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dp1 = NULL;
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dp2 = NULL;
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/* Read in master superblock */
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if ((ret = sbget(devfd, &sblock, STDSB)) != 0) {
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switch (ret) {
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case ENOENT:
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warn("Cannot find file system superblock");
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return (1);
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default:
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warn("Unable to read file system superblock");
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return (1);
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}
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}
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if (sblock->fs_magic == FS_UFS1_MAGIC &&
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sblock->fs_old_inodefmt < FS_44INODEFMT) {
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warnx("file system format is too old, sorry");
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return (1);
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}
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if (!force && !printonly && sblock->fs_clean != 1) {
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warnx("file system is not clean, fsck %s first", device);
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return (1);
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}
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/* XXX - should really cap buffer at 512kb or so */
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if (sblock->fs_magic == FS_UFS1_MAGIC)
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ibufsize = sizeof(struct ufs1_dinode) * sblock->fs_ipg;
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else
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ibufsize = sizeof(struct ufs2_dinode) * sblock->fs_ipg;
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if ((inodebuf = malloc(ibufsize)) == NULL)
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errx(1, "can't allocate memory for inode buffer");
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if (printonly && (sblock->fs_id[0] || sblock->fs_id[1])) {
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if (sblock->fs_id[0])
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(void)printf("%s was randomized on %s", device,
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ctime((void *)&(sblock->fs_id[0])));
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(void)printf("fsid: %x %x\n", sblock->fs_id[0],
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sblock->fs_id[1]);
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}
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/* Randomize fs_id unless old 4.2BSD file system */
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if (!printonly) {
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/* Randomize fs_id and write out new sblock and backups */
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sblock->fs_id[0] = (u_int32_t)time(NULL);
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sblock->fs_id[1] = random();
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if (sbput(devfd, sblock, sblock->fs_ncg) != 0) {
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warn("could not write updated superblock");
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return (1);
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}
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}
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/* For each cylinder group, randomize inodes and update backup sblock */
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for (cg = 0, inumber = UFS_ROOTINO; cg < (int)sblock->fs_ncg; cg++) {
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/* Read in inodes, then print or randomize generation nums */
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dblk = fsbtodb(sblock, ino_to_fsba(sblock, inumber));
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if (lseek(devfd, (off_t)dblk * bsize, SEEK_SET) < 0) {
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warn("can't seek to %jd", (intmax_t)dblk * bsize);
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return (1);
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} else if ((n = read(devfd, inodebuf, ibufsize)) != ibufsize) {
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warnx("can't read inodes: %s",
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(n < ibufsize) ? "short read" : strerror(errno));
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return (1);
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}
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dp1 = (struct ufs1_dinode *)(void *)inodebuf;
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dp2 = (struct ufs2_dinode *)(void *)inodebuf;
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for (n = cg > 0 ? 0 : UFS_ROOTINO;
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n < (int)sblock->fs_ipg;
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n++, inumber++) {
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if (printonly) {
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(void)printf("ino %ju gen %08x\n",
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(uintmax_t)inumber,
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sblock->fs_magic == FS_UFS1_MAGIC ?
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dp1->di_gen : dp2->di_gen);
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} else if (sblock->fs_magic == FS_UFS1_MAGIC) {
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dp1->di_gen = arc4random();
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dp1++;
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} else {
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dp2->di_gen = arc4random();
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dp2++;
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}
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}
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/* Write out modified inodes */
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if (!printonly) {
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if (lseek(devfd, (off_t)dblk * bsize, SEEK_SET) < 0) {
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warn("can't seek to %jd",
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(intmax_t)dblk * bsize);
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return (1);
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} else if ((n = write(devfd, inodebuf, ibufsize)) !=
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ibufsize) {
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warnx("can't write inodes: %s",
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(n != ibufsize) ? "short write" :
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strerror(errno));
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return (1);
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}
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}
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}
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(void)close(devfd);
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return(0);
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}
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static void
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usage(void)
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{
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(void)fprintf(stderr,
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"usage: fsirand [-b] [-f] [-p] special [special ...]\n");
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exit(1);
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}
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