[Libguestfs] [PATCH common v2 4/4] options: Ignore errors from guestfs_luks_uuid.

[Martin Kletzander]

On Wed, Oct 07, 2020 at 09:25:15AM +0200, Martin Kletzander wrote:
>On Tue, Oct 06, 2020 at 03:06:54PM +0100, Richard W.M. Jones wrote:
>>On Tue, Oct 06, 2020 at 03:25:20PM +0200, Martin Kletzander wrote:
>>> On Mon, Sep 07, 2020 at 10:41:20AM +0100, Richard W.M. Jones wrote:
>>> >For BitLocker disks cryptsetup does not (yet? ever?) support reading
>>> >UUIDs and this function will fail.  This does not matter here so just
>>> >ignore the error.
>>> >
>>> >Note there is no error message, cryptsetup simply returns with a bad
>>> >exit code:
>>> >
>>> >><rescue> cryptsetup luksUUID /dev/sda2
>>> >><rescue> echo $?
>>> >1
>>> >
>>> >Updates commit bb4a2dc17a78b53437896d4215ae82df8e11b788.
>>> >---
>>> >options/decrypt.c | 15 ++++++++++++++-
>>> >1 file changed, 14 insertions(+), 1 deletion(-)
>>> >
>>> >diff --git a/options/decrypt.c b/options/decrypt.c
>>> >index 8eb24bc..6b1c0a8 100644
>>> >--- a/options/decrypt.c
>>> >+++ b/options/decrypt.c
>>> >@@ -25,6 +25,7 @@
>>> >
>>> >#include <stdio.h>
>>> >#include <stdlib.h>
>>> >+#include <stdbool.h>
>>> >#include <string.h>
>>> >#include <libintl.h>
>>> >#include <error.h>
>>> >@@ -82,11 +83,23 @@ inspect_do_decrypt (guestfs_h *g, struct key_store *ks)
>>> >    CLEANUP_FREE char *type = guestfs_vfs_type (g, partitions[i]);
>>> >    if (type &&
>>> >        (STREQ (type, "crypto_LUKS") || STREQ (type, "BitLocker"))) {
>>> >+      bool is_bitlocker = STREQ (type, "BitLocker");
>>> >      char mapname[32];
>>> >      make_mapname (partitions[i], mapname, sizeof mapname);
>>> >
>>> >#ifdef GUESTFS_HAVE_LUKS_UUID
>>> >-      CLEANUP_FREE char *uuid = guestfs_luks_uuid (g, partitions[i]);
>>> >+      CLEANUP_FREE char *uuid;
>>> >+      if (!is_bitlocker)
>>> >+        uuid = guestfs_luks_uuid (g, partitions[i]);
>>> >+      else {
>>> >+        /* This may fail for Windows BitLocker disks because
>>> >+         * cryptsetup luksUUID cannot read a UUID (unclear if
>>> >+         * this is a limitation of the format or cryptsetup).
>>> >+         */
>>> >+        guestfs_push_error_handler (g, NULL, NULL);
>>> >+        uuid = guestfs_luks_uuid (g, partitions[i]);
>>>
>>> I have yet to look at the libguestfs patches, but I do not completely understand
>>> what is the reason for calling "guestfs_luks_uuid" when you know it will fail.
>>> Or is there a case when it might be useful to get the result?
>>
>>Yes I don't know what I was thinking there.  It's difficult to revisit
>>and revise patches months later.  It would be better as simply:
>>
>>diff --git a/options/decrypt.c b/options/decrypt.c
>>index 8eb24bc..ca2a0bb 100644
>>--- a/options/decrypt.c
>>+++ b/options/decrypt.c
>>@@ -25,6 +25,7 @@
>>
>> #include <stdio.h>
>> #include <stdlib.h>
>>+#include <stdbool.h>
>> #include <string.h>
>> #include <libintl.h>
>> #include <error.h>
>>@@ -82,11 +83,19 @@ inspect_do_decrypt (guestfs_h *g, struct key_store *ks)
>>     CLEANUP_FREE char *type = guestfs_vfs_type (g, partitions[i]);
>>     if (type &&
>>         (STREQ (type, "crypto_LUKS") || STREQ (type, "BitLocker"))) {
>>+      bool is_bitlocker = STREQ (type, "BitLocker");
>>       char mapname[32];
>>       make_mapname (partitions[i], mapname, sizeof mapname);
>>
>> #ifdef GUESTFS_HAVE_LUKS_UUID
>>-      CLEANUP_FREE char *uuid = guestfs_luks_uuid (g, partitions[i]);
>>+      CLEANUP_FREE char *uuid = NULL;
>>+
>>+      /* This fails for Windows BitLocker disks because cryptsetup
>>+       * luksUUID cannot read a UUID (unclear if this is a limitation
>>+       * of the format or cryptsetup).
>>+       */
>>+      if (!is_bitlocker)
>>+        uuid = guestfs_luks_uuid (g, partitions[i]);
>> #else
>>       const char *uuid = NULL;
>> #endif
>>
>>Rich.
>>
>
>Glad I understood it then, ACK to that.
>

Oops, unfortunately that broke the php bindings =D But I'm guessing that again
just needs a different include path.  I only noticed it now when building Fedora
32 with all the build dependencies installed.

>>--
>>Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
>>Read my programming and virtualization blog: http://rwmj.wordpress.com
>>virt-builder quickly builds VMs from scratch
>>http://libguestfs.org/virt-builder.1.html



>_______________________________________________
>Libguestfs mailing list
>Libguestfs at redhat.com
>https://www.redhat.com/mailman/listinfo/libguestfs

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/libguestfs/attachments/20201009/e2cf81a0/attachment.sig>