The branch main has been updated by pho: URL: https://cgit.FreeBSD.org/src/commit/?id=6fbbb4806322e61e5b838e4160af12b821f99f0c
commit 6fbbb4806322e61e5b838e4160af12b821f99f0c Author: Kirk McKusick <[email protected]> AuthorDate: 2022-02-13 09:47:20 +0000 Commit: Peter Holm <[email protected]> CommitDate: 2022-02-13 09:47:20 +0000 stress2: Added a tool to zero out a superblock check hash. --- tools/test/stress2/tools/zapsb.c | 75 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) diff --git a/tools/test/stress2/tools/zapsb.c b/tools/test/stress2/tools/zapsb.c new file mode 100644 index 000000000000..09e16e27c322 --- /dev/null +++ b/tools/test/stress2/tools/zapsb.c @@ -0,0 +1,75 @@ +/* + * Zero out a superblock check hash. + * By Kirk McKusick <[email protected]> + */ + +#include <sys/param.h> +#include <sys/disklabel.h> + +#include <ufs/ufs/dinode.h> +#include <ufs/ffs/fs.h> + +#include <err.h> +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <unistd.h> + +/* + * Possible superblock locations ordered from most to least likely. + */ +static int sblock_try[] = SBLOCKSEARCH; + +static void +usage(void) +{ + (void)fprintf(stderr, "usage: zapsb special_device\n"); + exit(1); +} + +int +main(int argc, char *argv[]) +{ + char *fs, sblock[SBLOCKSIZE]; + struct fs *sbp; + int i, fd; + + if (argc != 2) + usage(); + + fs = *++argv; + + /* get the superblock. */ + if ((fd = open(fs, O_RDWR, 0)) < 0) + err(1, "%s", fs); + for (i = 0; sblock_try[i] != -1; i++) { + if (lseek(fd, (off_t)(sblock_try[i]), SEEK_SET) < 0) + err(1, "%s", fs); + if (read(fd, sblock, sizeof(sblock)) != sizeof(sblock)) + errx(1, "%s: can't read superblock", fs); + sbp = (struct fs *)sblock; + if ((sbp->fs_magic == FS_UFS1_MAGIC || + (sbp->fs_magic == FS_UFS2_MAGIC && + sbp->fs_sblockloc == sblock_try[i])) && + sbp->fs_bsize <= MAXBSIZE && + sbp->fs_bsize >= (int)sizeof(struct fs)) + break; + } + if (sblock_try[i] == -1) { + fprintf(stderr, "Cannot find file system superblock\n"); + exit(2); + } + if ((sbp->fs_metackhash & CK_SUPERBLOCK) == 0) { + fprintf(stderr, "file system superblock has no check hash\n"); + exit(3); + } + printf("zeroing superblock checksum at location %d\n", sblock_try[i]); + sbp->fs_ckhash = 0; + if (lseek(fd, (off_t)(sblock_try[i]), SEEK_SET) < 0) + err(1, "%s", fs); + if (write(fd, sblock, sizeof(sblock)) != sizeof(sblock)) + errx(1, "%s: can't write superblock", fs); + (void)close(fd); + exit(0); +}
