RFC: Canonicalize block device paths

There are many naming conventions for partitions associated with a
block device.  Some of the major ones are:

/dev/foo -> /dev/foo1
/dev/foo1 -> /dev/foo1p1
/dev/mapper/foo -> /dev/mapper/foop1
/dev/disk/by-path/foo -> /dev/disk/by-path/foo-part1

The universe of possible conventions isn't clear.  Rather than trying
to understand all possible conventions, this patch divides devices
into two groups, device mapper devices and everything else.  Device
mapper devices seem always to follow the convention of device ->
devicep1; everything else is canonicalized.
This commit is contained in:
David Allan 2010-07-08 18:04:26 -04:00
parent a3fc67a12c
commit ae3275c0bb
2 changed files with 40 additions and 4 deletions

View File

@ -1037,8 +1037,13 @@ libexec_PROGRAMS += libvirt_parthelper
libvirt_parthelper_SOURCES = $(STORAGE_HELPER_DISK_SOURCES)
libvirt_parthelper_LDFLAGS = $(WARN_LDFLAGS) $(COVERAGE_LDFLAGS)
libvirt_parthelper_LDADD = $(LIBPARTED_LIBS) ../gnulib/lib/libgnu.la
libvirt_parthelper_CFLAGS = $(LIBPARTED_CFLAGS)
libvirt_parthelper_LDADD = \
$(LIBPARTED_LIBS) \
$(DEVMAPPER_LIBS) \
libvirt_util.la \
../gnulib/lib/libgnu.la
libvirt_parthelper_CFLAGS = $(LIBPARTED_CFLAGS) $(DEVMAPPER_CFLAGS)
endif
endif
EXTRA_DIST += $(STORAGE_HELPER_DISK_SOURCES)

View File

@ -35,7 +35,12 @@
#include <parted/parted.h>
#include <stdio.h>
#include <string.h>
#include <libdevmapper.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include "util.h"
#include "c-ctype.h"
/* we don't need to include the full internal.h just for this */
@ -52,6 +57,18 @@ enum diskCommand {
DISK_GEOMETRY
};
static int
is_dm_device(const char *devname)
{
struct stat buf;
if (devname && !stat(devname, &buf) && dm_is_dm_major(major(buf.st_rdev))) {
return 1;
}
return 0;
}
int main(int argc, char **argv)
{
PedDevice *dev;
@ -59,6 +76,7 @@ int main(int argc, char **argv)
PedPartition *part;
int cmd = DISK_LAYOUT;
const char *path;
char *canonical_path;
const char *partsep;
if (argc == 3 && STREQ(argv[2], "-g")) {
@ -69,7 +87,20 @@ int main(int argc, char **argv)
}
path = argv[1];
partsep = *path && c_isdigit(path[strlen(path)-1]) ? "p" : "";
if (is_dm_device(path)) {
partsep = "p";
canonical_path = strdup(path);
if (canonical_path == NULL) {
return 2;
}
} else {
if (virFileResolveLink(path, &canonical_path) != 0) {
return 2;
}
partsep = *canonical_path &&
c_isdigit(canonical_path[strlen(canonical_path)-1]) ? "p" : "";
}
if ((dev = ped_device_get(path)) == NULL) {
fprintf(stderr, "unable to access device %s\n", path);
@ -125,7 +156,7 @@ int main(int argc, char **argv)
*/
if (part->num != -1) {
printf("%s%s%d%c%s%c%s%c%llu%c%llu%c%llu%c",
path, partsep,
canonical_path, partsep,
part->num, '\0',
type, '\0',
content, '\0',