ericonr
/
util-linux
mirror of https://github.com/ericonr/util-linux.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

blkdiscard: Refuse to proceed if signatures are found 

Currently the blkdiscard has the ability to wipe out entere device in a
matter of seconds. This is fine as long as it's intentional, it is
potentially catastrophic if it's not.

With this commit blkdiscard will check for existing signatures on the
device and refuse to continue if any are found unless the operation is
forced with the -f option.

In an attempt to avoid breaking existing automation scripts the force is
only required when stdin refers to a terminal.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
This commit is contained in:
Lukas Czerner 2020-06-18 12:50:34 +02:00 committed by Karel Zak
parent 8f3ce436b8
commit 0f23e4c13e
2 changed files with 59 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys-utils/Makemodule.am
View File

@ -165,7 +165,7 @@ if BUILD_BLKDISCARD
sbin_PROGRAMS += blkdiscard
dist_man_MANS += sys-utils/blkdiscard.8
blkdiscard_SOURCES = sys-utils/blkdiscard.c lib/monotonic.c
blkdiscard_LDADD = $(LDADD) libcommon.la $(REALTIME_LIBS)
blkdiscard_LDADD = $(LDADD) libblkid.la libcommon.la $(REALTIME_LIBS)
endif
if BUILD_BLKZONE

59
sys-utils/blkdiscard.c
View File

@ -37,6 +37,7 @@
#include <sys/stat.h>
#include <sys/time.h>
#include <linux/fs.h>
#include <blkid/blkid.h>
#include "nls.h"
#include "strutils.h"
@ -106,6 +107,41 @@ static void __attribute__((__noreturn__)) usage(void)
exit(EXIT_SUCCESS);
}
/*
* Check existing signature on the open fd
* Returns 0 signature found
* 1 no signature
* <0 error
*/
static int probe_device(int fd, char *path)
{
const char *type;
blkid_probe pr = NULL;
int ret = -1;
pr = blkid_new_probe();
if (!pr || blkid_probe_set_device(pr, fd, 0, 0))
return ret;
blkid_probe_enable_superblocks(pr, TRUE);
blkid_probe_enable_partitions(pr, TRUE);
ret = blkid_do_fullprobe(pr);
if (ret)
goto out;
if (!blkid_probe_lookup_value(pr, "TYPE", &type, NULL)) {
warnx("%s contains existing file system (%s).",path ,type);
} else if (!blkid_probe_lookup_value(pr, "PTTYPE", &type, NULL)) {
warnx("%s contains existing partition (%s).",path ,type);
} else {
warnx("%s contains existing signature.", path);
}
out:
blkid_free_probe(pr);
return ret;
}
int main(int argc, char **argv)
{
@ -184,7 +220,7 @@ int main(int argc, char **argv)
errtryhelp(EXIT_FAILURE);
}
fd = open(path, O_WRONLY | (force ? 0 : O_EXCL));
fd = open(path, O_RDWR | (force ? 0 : O_EXCL));
if (fd < 0)
err(EXIT_FAILURE, _("cannot open %s"), path);
@ -217,6 +253,27 @@ int main(int argc, char **argv)
errx(EXIT_FAILURE, _("%s: length %" PRIu64 " is not aligned "
"to sector size %i"), path, range[1], secsize);
/* Check for existing signatures on the device */
switch(probe_device(fd, path)) {
case 0: /* signature detected */
/*
* Only require force in interactive mode to avoid
* breaking existing scripts
*/
if (!force && isatty(STDIN_FILENO)) {
errx(EXIT_FAILURE,
_("This is destructive operation, data will " \
"be lost! Use the -f option to override."));
}
warnx(_("Operation forced, data will be lost!"));
break;
case 1: /* no signature */
break;
default: /* error */
err(EXIT_FAILURE, _("failed to probe the device"));
break;
}
stats[0] = range[0], stats[1] = 0;
gettime_monotonic(&last);