Re: Patch to support LUKS UUIDs in libblkid

[Karsten Hopp <karsten@redhat.com>]

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Theodore Tso schrieb:
> On Mon, Jun 11, 2007 at 01:51:24PM +0200, Karsten Hopp wrote:
>> +static int probe_luks(struct blkid_probe *probe,
>> +		       struct blkid_magic *id __BLKID_ATTR((unused)), 
>> +		       unsigned char *buf)
>> +{
>> +	unsigned char *p_buf = buf;
>> +	unsigned char uuid[40];
>> +	/* 168 is the offset to the 40 character uuid: 
>> +	 * http://luks.endorphin.org/LUKS-on-disk-format.pdf */
>> +	p_buf += 168;
>> +	strncpy(uuid, p_buf, 40);
> 
> Why bother with p_buf?  It would actually be shorter and sweeter to
> do:
> 
> 	strncpy(uuid, buf+168, 40);
> 
> And remove the lines dealing with p_buf above.
> 
>> +  { "crypt_LUKS",0,	 0,  6,	"LUKS\xba\xbe",		probe_luks },
> 
> Any particular reason to use "crypt_LUKS" instead of just "LUKS"?  In
> your documentation you generally just refer to it as LUKS.
> 
> 					- Ted

I've used 'luks' in my first patch, but changed it to 'crypt_LUKS' when
Karel Zak pointed out that libvolume_id from udev already uses 'crypt_LUKS'
for this.
My first patch also did some other (unnecessary) stuff with p_buf and I just
didn't bother to remove it.
I'll attach a new patch without p_buf.

    Karsten

--
  Karsten Hopp        | Mail: karsten@redhat.de
  Red Hat Deutschland | Tel: +49-711-96437-0
  Hauptstaetterstr.58 | Fax: +49-711-613590
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[-- Attachment #2: e2fsprogs-1.39-luks.patch --]
[-- Type: text/x-patch, Size: 1573 bytes --]

e2fsprogs-1.39-luks.patch
Problem:        libblkid doesn't detect/report UUIDs of cryptsetup-luks partitio
ns
Solution:       Add probe for luks UUID
Signed-off-by:  Karsten Hopp <karsten@redhat.com>

--- e2fsprogs-1.39/lib/blkid/ChangeLog.luksuuid	2007-06-11 13:40:14.000000000 +0200
+++ e2fsprogs-1.39/lib/blkid/ChangeLog	2007-06-11 13:40:14.000000000 +0200
@@ -0,0 +1,4 @@
+2007-05-22  Karsten Hopp  <karsten@redhat.com> 
+
+	* probe.c (probe_luks): Add support for cryptsetup-luks partitions
+
--- e2fsprogs-1.39/lib/blkid/probe.c.luksuuid	2007-06-11 13:40:14.000000000 +0200
+++ e2fsprogs-1.39/lib/blkid/probe.c	2007-06-13 12:50:27.000000000 +0200
@@ -468,6 +468,18 @@ static int probe_jfs(struct blkid_probe 
 	return 0;
 }
 
+static int probe_luks(struct blkid_probe *probe,
+		       struct blkid_magic *id __BLKID_ATTR((unused)), 
+		       unsigned char *buf)
+{
+	unsigned char uuid[40];
+	/* 168 is the offset to the 40 character uuid: 
+	 * http://luks.endorphin.org/LUKS-on-disk-format.pdf */
+	strncpy(uuid, buf+168, 40);
+	blkid_set_tag(probe->dev, "UUID", uuid, sizeof(uuid));
+	return 0;
+}
+
 static int probe_romfs(struct blkid_probe *probe,
 		       struct blkid_magic *id __BLKID_ATTR((unused)), 
 		       unsigned char *buf)
@@ -775,6 +787,7 @@ static struct blkid_magic type_array[] =
   { "ocfs2",	 2,	 0,  6,	"OCFSV2",		probe_ocfs2 },
   { "ocfs2",	 4,	 0,  6,	"OCFSV2",		probe_ocfs2 },
   { "ocfs2",	 8,	 0,  6,	"OCFSV2",		probe_ocfs2 },
+  { "crypt_LUKS",0,	 0,  6,	"LUKS\xba\xbe",		probe_luks },
   {   NULL,	 0,	 0,  0, NULL,			NULL }
 };