parted/parted-gpt-mbr-sync.patch

---
 libparted/labels/gpt.c |  109 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 2 deletions(-)

Index: libparted/labels/gpt.c
===================================================================
--- libparted/labels/gpt.c.orig
+++ libparted/labels/gpt.c
@@ -51,6 +51,11 @@
 #  define _(String) (String)
 #endif /* ENABLE_NLS */
 
+/* IA64 always has a properly working EFI implementation */
+#ifndef __ia64__
+#define GPT_SYNC_MBR
+#endif
+
 #define EFI_PMBR_OSTYPE_EFI 0xEE
 #define MSDOS_MBR_SIGNATURE 0xaa55
 
@@ -1072,11 +1077,60 @@ error:
   return 0;
 }
 
+
+#ifdef GPT_SYNC_MBR
+static inline unsigned char
+_part_to_ostype (PedPartition* part)
+{
+    if (part->fs_type) {
+        if (strncmp (part->fs_type->name, "fat", 3) == 0) return 0xc;
+        if (strncmp (part->fs_type->name, "ntfs", 4) == 0) return 0x7;
+        if (strncmp (part->fs_type->name, "hfs", 3) == 0) return 0xaf;
+        if (strstr (part->fs_type->name, "swap")) return 0x82;
+    }
+    return 0x83; // Everything else is Linux
+}
+
+static inline PedPartition*
+_find_first_part (const PedDisk* disk)
+{
+    PedPartition *retval = NULL, *part = NULL;
+    uint64_t lowest_end = 0xffffffffffffffff;
+    while (part = ped_disk_next_partition (disk, part)) {
+        if (part->geom.start == 0 || part->type == PED_PARTITION_METADATA
+                || part->type == PED_PARTITION_FREESPACE)
+            continue;
+        if (part->geom.end < lowest_end) {
+            retval = part;
+            lowest_end = part->geom.end;
+        }
+    }
+    return retval;
+}
+
+static inline uint32_t
+_part_32bitmax (uint64_t in)
+{
+    if (in > 0xFFFFFFFFULL) 
+        return 0xFFFFFFFF;
+    else
+        return (uint32_t)in;
+}
+#endif
+
+
 #ifndef DISCOVER_ONLY
 /* Write the protective MBR (to keep DOS happy) */
 static int
-_write_pmbr (PedDevice *dev)
+_write_pmbr (const PedDisk *disk)
 {
+    PedDevice * dev = disk->dev;
+
+#ifdef GPT_SYNC_MBR
+    int i, pmbr_id, first_entry = 0, last_entry = 3;
+    PedPartition *part = NULL, *esp;
+#endif
+
   /* The UEFI spec is not clear about what to do with the following
      elements of the Protective MBR (pmbr): BootCode (0-440B),
      UniqueMBRSignature (440B-444B) and Unknown (444B-446B).
@@ -1086,10 +1140,13 @@ _write_pmbr (PedDevice *dev)
     return 0;
   LegacyMBR_t *pmbr = s0;
 
+#ifndef GPT_SYNC_MBR
   /* Zero out the legacy partitions.  */
   memset (pmbr->PartitionRecord, 0, sizeof pmbr->PartitionRecord);
+#endif
 
   pmbr->Signature = PED_CPU_TO_LE16 (MSDOS_MBR_SIGNATURE);
+#ifndef GPT_SYNC_MBR
   pmbr->PartitionRecord[0].OSType = EFI_PMBR_OSTYPE_EFI;
   pmbr->PartitionRecord[0].StartSector = 1;
   pmbr->PartitionRecord[0].EndHead = 0xFE;
@@ -1100,6 +1157,53 @@ _write_pmbr (PedDevice *dev)
     pmbr->PartitionRecord[0].SizeInLBA = PED_CPU_TO_LE32 (0xFFFFFFFF);
   else
     pmbr->PartitionRecord[0].SizeInLBA = PED_CPU_TO_LE32 (dev->length - 1UL);
+#else
+  /* Search for an EFI System Partition */
+  esp = _find_first_part(disk);
+  if (!esp || !esp->fs_type || strncmp (esp->fs_type->name, "fat", 3) != 0)
+      esp = NULL;
+
+  pmbr_id = 3;
+  if (esp) {
+      pmbr_id = 0;
+      first_entry = 1;
+      last_entry = 4;
+  }
+
+  /* Write a pseudo-PMBR so Linux is happy */
+  pmbr->PartitionRecord[pmbr_id].OSType      = EFI_PMBR_OSTYPE_EFI;
+  pmbr->PartitionRecord[pmbr_id].StartSector = 1;
+  pmbr->PartitionRecord[pmbr_id].EndHead     = 0xFE;
+  pmbr->PartitionRecord[pmbr_id].EndSector   = 0xFF;
+  pmbr->PartitionRecord[pmbr_id].EndTrack    = 0xFF;
+  pmbr->PartitionRecord[pmbr_id].StartingLBA = PED_CPU_TO_LE32(1);
+  pmbr->PartitionRecord[pmbr_id].SizeInLBA = 1;
+  if (esp)
+      pmbr->PartitionRecord[pmbr_id].SizeInLBA = esp->geom.end - 1;
+
+  /* sync the first 3 GPT entries to MBR primary partitions */
+  for (i=first_entry; i < last_entry; i++) {
+      part = ped_disk_next_partition (disk, part);
+      if (part == NULL)
+          break;
+      /* we might get a starting garbage partition */
+      if (part->geom.start == 0 || part->type == PED_PARTITION_METADATA || part->type == PED_PARTITION_FREESPACE || part == esp) {
+          i--;
+          continue;
+      }
+      pmbr->PartitionRecord[i].OSType      = _part_to_ostype(part);
+      pmbr->PartitionRecord[i].StartHead     = 0xFE;
+      pmbr->PartitionRecord[i].StartSector   = 0xFF;
+      pmbr->PartitionRecord[i].StartTrack    = 0xFF;
+      pmbr->PartitionRecord[i].EndHead     = 0xFE;
+      pmbr->PartitionRecord[i].EndSector   = 0xFF;
+      pmbr->PartitionRecord[i].EndTrack    = 0xFF;
+      pmbr->PartitionRecord[i].StartingLBA = _part_32bitmax(part->geom.start);
+      if(((GPTPartitionData*)part->disk_specific)->boot)
+          pmbr->PartitionRecord[i].BootIndicator = 0x80;
+      pmbr->PartitionRecord[i].SizeInLBA = _part_32bitmax(part->geom.end - part->geom.start + 1);
+  }
+#endif
 
   int write_ok = ped_device_write (dev, pmbr, GPT_PMBR_LBA,
                                    GPT_PMBR_SECTORS);
@@ -1216,7 +1320,7 @@ gpt_write (const PedDisk *disk)
   ptes_crc = efi_crc32 (ptes, ptes_size);
 
   /* Write protective MBR */
-  if (!_write_pmbr (disk->dev))
+  if (!_write_pmbr (disk))
     goto error_free_ptes;
 
   /* Write PTH and PTEs */