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mkswap: zap bootbits 

/dev/sdb1 originally initialized by cryptsetup:

and OLD mkswap:

        # vol_id /dev/sdb1 | grep TYPE
        ID_FS_TYPE=swap

        # blkid -s TYPE /dev/sdb1
        /dev/sdb1: TYPE="crypt_LUKS"

So, we have two different *valid* signatures on the device now!

NEW mkswap:

        # blkid -s TYPE /dev/sdb1
        /dev/sdb1: TYPE="swap"

        # /lib/udev/vol_id /dev/sdb1 | grep TYPE
        ID_FS_TYPE=swap

the bootbits (first 1024 bytes) was erased.

We shouldn't zap disk labels (BSD, SUN, ...) and boot loaders (on whole
disk):

        # mkswap  /dev/sdb2
        mkswap: /dev/sdb2: warning: don't erase bootbits sectors
                (BSD partition table detected). Use -f to force.
        Setting up swapspace version 1, size = 4348 KiB
        no label, UUID=69d87cef-71ac-4fb0-a689-ce3e930dea17

        # mkswap  /dev/sdb
        mkswap: /dev/sdb: warning: don't erase bootbits sectors
                on whole disk. Use -f to force.
        Setting up swapspace version 1, size = 8188 KiB
        no label, UUID=97757ad7-8a84-43d9-bcb4-16fefd93a2ac

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2009-03-12 16:01:59 +01:00
parent 015ea51c10
commit ff3bed8068
2 changed files with 46 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
disk-utils/Makefile.am
View File

@ -12,7 +12,7 @@ sbin_PROGRAMS = mkfs mkswap fsck.minix mkfs.minix mkfs.bfs
fsck_minix_SOURCES = fsck.minix.c minix.h
mkfs_minix_SOURCES = mkfs.minix.c minix.h $(utils_common)
mkfs_bfs_SOURCES = mkfs.bfs.c $(utils_common)
mkswap_SOURCES = mkswap.c $(utils_common)
mkswap_SOURCES = mkswap.c $(utils_common) ../lib/wholedisk.c ../lib/pttype.c
usrbinexec_PROGRAMS = isosize
usrsbinexec_PROGRAMS =

45
disk-utils/mkswap.c
View File

@ -53,6 +53,8 @@
#include "nls.h"
#include "blkdev.h"
#include "pathnames.h"
#include "pttype.h"
#include "wholedisk.h"
#ifdef HAVE_LIBUUID
#include <uuid/uuid.h>
@ -379,6 +381,47 @@ write_all(int fd, const void *buf, size_t count) {
return 0;
}
static void
zap_bootbits(int fd, const char *devname, int force)
{
const char *type = NULL;
int zap = 1;
if (!force) {
if (lseek(fd, 0, SEEK_SET) != 0)
die(_("unable to rewind swap-device"));
if (is_whole_disk_fd(fd, devname))
/* don't zap bootbits on whole disk -- we know nothing
* about bootloaders on the device */
zap = 0;
else if ((type = get_pt_type_fd(fd)))
/* don't zap partition table */
zap = 0;
}
if (zap) {
char buf[1024];
if (lseek(fd, 0, SEEK_SET) != 0)
die(_("unable to rewind swap-device"));
memset(buf, 0, sizeof(buf));
if (write_all(fd, buf, sizeof(buf)))
die(_("unable to erase bootbits sectors"));
return;
}
fprintf(stderr, _("%s: %s: warning: don't erase bootbits sectors\n"),
program_name, devname);
if (type)
fprintf(stderr, _(" (%s partition table detected). "), type);
else
fprintf(stderr, _(" on whole disk. "));
fprintf(stderr, "Use -f to force.\n");
}
int
main(int argc, char ** argv) {
struct stat statbuf;
@ -561,6 +604,8 @@ main(int argc, char ** argv) {
if (check)
check_blocks();
zap_bootbits(DEV, device_name, force);
p->version = 1;
p->last_page = PAGES-1;
p->nr_badpages = badpages;