kpartx: support device names with spaces

Device names with spaces fail to be added to device-mapper tables because spaces are field separators. In order to support it, use device major:minor numbers, instead. While still there, make the verbose output of container- and contained-slices consistent.

This is useful on some scenarios with arbitrary loop device names, and non-user_friendly_names multipath WWIDs with spaces (eg, QEMU emulated hard drives, and some IBM devices) on some distros.

Changelog:
- V2: Use major()/minor() instead of MAJOR()/MINOR() (build errors). Update test-case verification output.
Thanks: Christophe Varoqui

Test-case:

        # img="/tmp/my.img"
        # spacename="/dev/my space name"

        # truncate --size=1G "$img"
        # lodev=$(sudo losetup --find --show "$img")
        # ln -sf "$lodev" "$spacename"

        # ls -l $lodev "$spacename"
        brw-rw----. 1 root disk 7, 0 Jan 20 11:15 /dev/loop0
        lrwxrwxrwx. 1 root root   10 Jan 20 11:16 /dev/my space name ->

/dev/loop0

        # fdisk $lodev
        <...>

        # fdisk -l $lodev
        <...>
              Device Boot      Start         End      Blocks   Id  System
        /dev/loop0p1            2048      264191      131072   83  Linux
        /dev/loop0p2          264192      788479      262144   83  Linux
        /dev/loop0p3          788480     2097151      654336    5  Extended
        /dev/loop0p5          790528      856063       32768   83  Linux
        /dev/loop0p6          858112      989183       65536   83  Linux
        /dev/loop0p7          991232     1515519      262144   83  Linux

Without patch:

        # ./kpartx/kpartx -av "$spacename"
        device-mapper: reload ioctl on my\x20space\x20name1 failed:
Invalid argument
        create/reload failed on my space name1
        add map my space name1 (0:0): 0 262144 linear /dev/my space name
2048

device-mapper: reload ioctl on my\x20space\x20name2 failed:
Invalid argument
create/reload failed on my space name2
add map my space name2 (0:0): 0 524288 linear /dev/my space name
264192

device-mapper: reload ioctl on my\x20space\x20name3 failed:
Invalid argument
create/reload failed on my space name3
add map my space name3 (0:0): 0 2 linear /dev/my space name 788480

device-mapper: reload ioctl on my\x20space\x20name5 failed:
Invalid argument
add map my space name5 : 0 65536 linear /dev/my space name 790528

device-mapper: reload ioctl on my\x20space\x20name6 failed:
Invalid argument
add map my space name6 : 0 131072 linear /dev/my space name 858112

device-mapper: reload ioctl on my\x20space\x20name7 failed:
Invalid argument
add map my space name7 : 0 524288 linear /dev/my space name 991232

(note: line breaks added for clarity)

With patch:

        # ./kpartx/kpartx -av "$spacename"
        add map my space name1 (253:3): 0 262144 linear 7:0 2048
        add map my space name2 (253:4): 0 524288 linear 7:0 264192
        add map my space name3 (253:5): 0 2 linear 7:0 788480
        add map my space name5 (253:6): 0 65536 linear 7:0 790528
        add map my space name6 (253:7): 0 131072 linear 7:0 858112
        add map my space name7 (253:8): 0 524288 linear 7:0 991232

        # dmsetup table | sort
        my space name1: 0 262144 linear 7:0 2048
        my space name2: 0 524288 linear 7:0 264192
        my space name3: 0 2 linear 7:0 788480
        my space name5: 0 65536 linear 7:0 790528
        my space name6: 0 131072 linear 7:0 858112
        my space name7: 0 524288 linear 7:0 991232

        # ls -l /dev/mapper/
        total 0
        crw-------. 1 root root 10, 236 Jan 11 16:29 control
        lrwxrwxrwx. 1 root root       7 Jan 20 11:19 my\x20space\x20name1
-> ../dm-3
        lrwxrwxrwx. 1 root root       7 Jan 20 11:19 my\x20space\x20name2
-> ../dm-4
        lrwxrwxrwx. 1 root root       7 Jan 20 11:19 my\x20space\x20name3
-> ../dm-5
        lrwxrwxrwx. 1 root root       7 Jan 20 11:19 my\x20space\x20name5
-> ../dm-6
        lrwxrwxrwx. 1 root root       7 Jan 20 11:19 my\x20space\x20name6
-> ../dm-7
        lrwxrwxrwx. 1 root root       7 Jan 20 11:19 my\x20space\x20name7
-> ../dm-8

Thanks: Scott Moser (pointers to the error and test-case).

Signed-off-by Mauricio Faria de Oliveira <[email protected]>

---
 kpartx/kpartx.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

kpartx/kpartx.c +2 -2

index a9d4c98..ee7c38a 100644
@@ -477,8 +477,8 @@ main(int argc, char **argv){
                                }
                                strip_slash(partname);
 
-                               if (safe_sprintf(params, "%s %" PRIu64 ,
-                                                device, slices[j].start))
 {
+                               if (safe_sprintf(params, "%d:%d %" PRIu64 ,
+                                                major(buf.st_rdev),
 minor(buf.st_rdev), slices[j].start)) {
                                        fprintf(stderr, "params too

small\n");
                                        exit(1);
                                }

kpartx/kpartx.c +2 -2

@@ -540,8 +540,8 @@ main(int argc, char **argv){
                                        }
                                        strip_slash(partname);
 
-                                       if (safe_sprintf(params, "%s %"
 PRIu64,
-                                                        device,
+                                       if (safe_sprintf(params, "%d:%d %"
 PRIu64,
+
 major(buf.st_rdev), minor(buf.st_rdev),

                                                         slices[j].start))
{
                                                fprintf(stderr, "params
too small\n");
                                                exit(1);

kpartx/kpartx.c +2 -2

@@ -563,8 +563,8 @@ main(int argc, char **argv){
                                                &slices[j].minor);
 
                                        if (verbose)
-                                               printf("add map %s : 0 %"
 PRIu64 " %s %s\n",
-                                                      partname,
 slices[j].size,
+                                               printf("add map %s
 (%d:%d): 0 %" PRIu64 " %s %s\n",
+                                                      partname,

slices[j].major, slices[j].minor, slices[j].size,

                                                       DM_TARGET, params);
                                        c--;
                                }

--
1.8.3.1

Applied,
thanks.

Applied,
thanks.

Quoted 3 lines · Christophe Varoqui

Applied,
thanks.

This patch apparently breaks the use of loopback-mounted files if you try to use them directly with kpartx -av.

For instance:
qemu-img create foo.img 20M
sgdisk -n 1 foo.img
kpartx -av foo.img

Fails with the following error:
device-mapper: reload ioctl on loop0p1 failed: No such device create/reload failed on loop0p1
add map loop0p1 (0:0): 0 4192256 linear 0:0 2048

This can be fixed by stat()'ing the loop device again after picking it:

kpartx/kpartx.c +5 -1

@@ -322,6 +322,11 @@ main(int argc, char **argv){
                        loopcreated = 1;
                }
                device = loopdev;
+
+               if (stat(device, &buf)) {
+                       printf("failed to stat() %s\n", device);
+                       exit (1);
+               }
        }
 
        off = find_devname_offset(device);
 
 
 
 
--

Mathieu Trudel-Lapierre <[email protected]>
Freenode: cyphermox, Jabber: [email protected] 4096R/65B58DA1 818A D123 0992 275B 23C2 CF89 C67B B4D6 65B5 8DA1

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