[PATCH 1 of 6] pygrub should check all GPT partitions

[PATCH 1 of 6] pygrub should check all GPT partitions

[M A Young]

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On Fedora 16 the first GPT partition is a boot partition for grub2 with
the grub2 configuration in the second partition.
Check all GPT partitions for grub configuration, not just the first.
Signed-off-by: Michael Young <m.a.young@durham.ac.uk>

--- a/tools/pygrub/src/pygrub	2011-10-16 20:58:02.000000000 +0100
+++ b/tools/pygrub/src/pygrub	2011-10-16 20:59:52.000000000 +0100
@@ -78,9 +78,17 @@
 def get_fs_offset_gpt(file):
     fd = os.open(file, os.O_RDONLY)
     # assume the first partition is an EFI system partition.
-    os.lseek(fd, SECTOR_SIZE * 2, 0)
+    os.lseek(fd, SECTOR_SIZE, 0)
     buf = os.read(fd, 512)
-    return struct.unpack("<Q", buf[32:40])[0] * SECTOR_SIZE
+    partcount = struct.unpack("<L", buf[80:84])[0]
+    partsize = struct.unpack("<L", buf[84:88])[0]
+    i = partcount
+    offsets = []
+    while i>0:
+        buf = os.read(fd, partsize)
+        offsets.append(struct.unpack("<Q", buf[32:40])[0] * SECTOR_SIZE)
+        i -= 1
+    return offsets
 
 FDISK_PART_SOLARIS=0xbf
 FDISK_PART_SOLARIS_OLD=0x82
@@ -114,7 +122,9 @@
                 continue # no solaris magic at that offset, ignore partition
 
         if type == FDISK_PART_GPT:
-            offset = get_fs_offset_gpt(file)
+            for offset in get_fs_offset_gpt(file):
+                part_offs.append(offset)
+            break
 
         # Active partition has 0x80 as the first byte.
         # If active, prepend to front of list, otherwise append to back.

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Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[Paolo Bonzini]

The patches are not enough to get "e" to work, but still an improvement 
of course, so:

Tested-by: Paolo Bonzini <pbonzini@redhat.com>

Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[Ian Campbell]

On Thu, 2011-10-20 at 08:38 +0100, Paolo Bonzini wrote:
> The patches are not enough to get "e" to work, but still an improvement 
> of course, so:

"e" ?

Ian.

Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[Paolo Bonzini]

On 10/20/2011 10:25 AM, Ian Campbell wrote:
>> >  The patches are not enough to get "e" to work, but still an improvement
>> >  of course, so:
> "e" ?

Edit entry mode.  It fails with a curses error when I use it on the F16 
grub2.cfg, which is what prompted me to do the patch for NotFoundError.

Paolo

Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[Ian Campbell]

On Thu, 2011-10-20 at 09:52 +0100, Paolo Bonzini wrote:
> On 10/20/2011 10:25 AM, Ian Campbell wrote:
> >> >  The patches are not enough to get "e" to work, but still an improvement
> >> >  of course, so:
> > "e" ?
> 
> Edit entry mode.  It fails with a curses error when I use it on the F16 
> grub2.cfg, which is what prompted me to do the patch for NotFoundError.

Ah, right. Cool thanks.

Ian.

Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[Ian Campbell]

On Thu, 2011-10-20 at 00:03 +0100, M A Young wrote:
> On Fedora 16 the first GPT partition is a boot partition for grub2
> with
> the grub2 configuration in the second partition.
> Check all GPT partitions for grub configuration, not just the first.
> Signed-off-by: Michael Young <m.a.young@durham.ac.uk>
> 
> --- a/tools/pygrub/src/pygrub   2011-10-16 20:58:02.000000000 +0100
> +++ b/tools/pygrub/src/pygrub   2011-10-16 20:59:52.000000000 +0100
> @@ -78,9 +78,17 @@
>  def get_fs_offset_gpt(file):
>      fd = os.open(file, os.O_RDONLY)
>      # assume the first partition is an EFI system partition.

Is this comment now inaccurate?

> -    os.lseek(fd, SECTOR_SIZE * 2, 0)
> +    os.lseek(fd, SECTOR_SIZE, 0)
>      buf = os.read(fd, 512)
> -    return struct.unpack("<Q", buf[32:40])[0] * SECTOR_SIZE
> +    partcount = struct.unpack("<L", buf[80:84])[0]
> +    partsize = struct.unpack("<L", buf[84:88])[0]
> +    i = partcount
> +    offsets = []
> +    while i>0:
> +        buf = os.read(fd, partsize)
> +        offsets.append(struct.unpack("<Q", buf[32:40])[0] *
> SECTOR_SIZE)
> +        i -= 1
> +    return offsets
>  
>  FDISK_PART_SOLARIS=0xbf
>  FDISK_PART_SOLARIS_OLD=0x82
> @@ -114,7 +122,9 @@
>                  continue # no solaris magic at that offset, ignore
> partition
>  
>          if type == FDISK_PART_GPT:
> -            offset = get_fs_offset_gpt(file)
> +            for offset in get_fs_offset_gpt(file):
> +                part_offs.append(offset)
> +            break
>  
>          # Active partition has 0x80 as the first byte.
>          # If active, prepend to front of list, otherwise append to
> back.
> 
> 

Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[M A Young]

On Thu, 20 Oct 2011, Ian Campbell wrote:

> On Thu, 2011-10-20 at 00:03 +0100, M A Young wrote:
>> On Fedora 16 the first GPT partition is a boot partition for grub2
>> with
>> the grub2 configuration in the second partition.
>> Check all GPT partitions for grub configuration, not just the first.
>> Signed-off-by: Michael Young <m.a.young@durham.ac.uk>
>>
>> --- a/tools/pygrub/src/pygrub   2011-10-16 20:58:02.000000000 +0100
>> +++ b/tools/pygrub/src/pygrub   2011-10-16 20:59:52.000000000 +0100
>> @@ -78,9 +78,17 @@
>>  def get_fs_offset_gpt(file):
>>      fd = os.open(file, os.O_RDONLY)
>>      # assume the first partition is an EFI system partition.
>
> Is this comment now inaccurate?

Yes. I haven't tested the case where the first partition is an EFI system 
partition though I think my changes would be harmless.

 	Michael Young

Re: [PATCH 1 of 6] pygrub should check all GPT partitions

[Ian Jackson]

M A Young writes ("[Xen-devel] [PATCH 1 of 6] pygrub should check all GPT partitions"):
> On Fedora 16 the first GPT partition is a boot partition for grub2 with
> the grub2 configuration in the second partition.
> Check all GPT partitions for grub configuration, not just the first.

Thanks.  I have applied all six of these.  I also removed this
obsolete comment:

>      # assume the first partition is an EFI system partition.

and fixed up the commit messages a bit.

Thanks,
Ian.