[PATCH v5 02/16] partmap/msdos: Add grub_mbr_partition_get_uuid()

[Vitaly Kuzmichev]

This patch adds a function to provide partition PARTUUID on MBR
formatted disks by extracting 32-bit disk signature code from MBR
at offset 0x01B8 and adding partition number to it, similarly to
'blkid' output.

Signed-off-by: Vitaly Kuzmichev <vitaly.kuzmichev@rtsoft.de>
---
 grub-core/partmap/msdos.c      | 32 ++++++++++++++++++++++++++++++++
 include/grub/msdos_partition.h |  3 +++
 2 files changed, 35 insertions(+)

diff --git a/grub-core/partmap/msdos.c b/grub-core/partmap/msdos.c
index c85bb74be..4ad9ea74f 100644
--- a/grub-core/partmap/msdos.c
+++ b/grub-core/partmap/msdos.c
@@ -24,12 +24,44 @@
 #include <grub/misc.h>
 #include <grub/dl.h>
 #include <grub/i18n.h>
+#include <grub/i386/pc/boot.h>
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
 static struct grub_partition_map grub_msdos_partition_map;
 
 
+char *
+grub_mbr_partition_get_uuid (grub_device_t dev)
+{
+  grub_disk_t disk;
+  grub_partition_t pt;
+  grub_uint32_t disk_uuid;
+  char *part_uuid = NULL;
+
+  if (dev && dev->disk && dev->disk->partition && 
dev->disk->partition->partmap)
+    {
+      pt = dev->disk->partition;
+      if (grub_strcmp (pt->partmap->name, "msdos") == 0)
+       {
+         disk = grub_disk_open (dev->disk->name);
+         if (disk && grub_disk_read (disk, 0,
+                                     GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC,
+                                     sizeof (disk_uuid), &disk_uuid) == 0)
+           part_uuid = grub_xasprintf ("%08x-%02x",
+                                       grub_le_to_cpu32 (disk_uuid),
+                                       pt->number + 1);
+         if (!part_uuid)
+           grub_error_push ();
+         grub_disk_close (disk);
+         if (!part_uuid)
+           grub_error_pop ();
+       }
+    }
+
+  return part_uuid;
+}
+
 #ifdef GRUB_UTIL
 #include <grub/emu/misc.h>
 
diff --git a/include/grub/msdos_partition.h b/include/grub/msdos_partition.h
index fdc2904d3..ff7600915 100644
--- a/include/grub/msdos_partition.h
+++ b/include/grub/msdos_partition.h
@@ -124,4 +124,7 @@ grub_partition_msdos_iterate (grub_disk_t disk,
                              grub_partition_iterate_hook_t hook,
                              void *hook_data);
 
+char *
+grub_mbr_partition_get_uuid (grub_device_t dev);
+
 #endif /* ! GRUB_PC_PARTITION_HEADER */
-- 
2.34.1