[parted-devel] [PATCH] gpt: support padding between Partition Header and Partition Table.

[Tzu-Jung Lee]

From: =Tzu-Jung Lee <roylee17 at currant.com>

Some SoC requires their booting code at a specific location, which
might conflict with the default layout of GPT.

Supporting a specified PartitionEntryLBA is required in this case.

Signed-off-by: Tzu-Jung Lee <roylee17 at currant.com>

diff --git a/include/parted/device.in.h b/include/parted/device.in.h
index 82d4104..1ce7a97 100644
--- a/include/parted/device.in.h
+++ b/include/parted/device.in.h
@@ -87,6 +87,8 @@ struct _PedDevice {
         int             dirty;
         int             boot_dirty;
 
+        int             pte_lba;
+
         PedCHSGeometry  hw_geom;
         PedCHSGeometry  bios_geom;
         short           host, did;
diff --git a/libparted/labels/gpt.c b/libparted/labels/gpt.c
index d69377a..004efce 100644
--- a/libparted/labels/gpt.c
+++ b/libparted/labels/gpt.c
@@ -499,6 +499,7 @@ gpt_probe (const PedDevice *dev)
       || ped_device_read (dev, pth_raw, dev->length - 1, GPT_HEADER_SECTORS))
     {
       GuidPartitionTableHeader_t *gpt = pth_new_from_raw (dev, pth_raw);
+      ((PedDevice*)dev)->pte_lba = gpt->PartitionEntryLBA;
       if (gpt->Signature == PED_CPU_TO_LE64 (GPT_HEADER_SIGNATURE))
         gpt_sig_found = 1;
       pth_free (gpt);
@@ -519,8 +520,8 @@ gpt_alloc (const PedDevice *dev)
   if (!disk)
     goto error;
 
-  data_start = 2 + GPT_DEFAULT_PARTITION_ENTRY_ARRAY_SIZE / dev->sector_size;
-  data_end = dev->length - 2
+  data_start = dev->pte_lba + GPT_DEFAULT_PARTITION_ENTRY_ARRAY_SIZE / dev->sector_size;
+  data_end = dev->length - dev->pte_lba
     - GPT_DEFAULT_PARTITION_ENTRY_ARRAY_SIZE / dev->sector_size;
 
   /* If the device is too small to accommodate GPT headers and one data
@@ -743,14 +744,14 @@ _parse_header (PedDisk *disk, const GuidPartitionTableHeader_t *gpt,
   last_usable = PED_LE64_TO_CPU (gpt->LastUsableLBA);
 
   /* Need to check whether the volume has grown, the LastUsableLBA is
-     normally set to disk->dev->length - 2 - ptes_size (at least for parted
-     created volumes), where ptes_size is the number of entries *
+     normally set to disk->dev->length - disb->dev->pte_lba - ptes_size (at least 
+     for parted created volumes), where ptes_size is the number of entries *
      size of each entry / sector size or 16k / sector size, whatever the greater.
      If the volume has grown, offer the user the chance to use the new
      space or continue with the current usable area.  Only ask once per
      parted invocation. */
 
-  last_usable_if_grown = disk->dev->length - 2 - _ptes_sectors(disk, gpt);
+  last_usable_if_grown = disk->dev->length - disk->dev->pte_lba - _ptes_sectors(disk, gpt);
 
   if (last_usable <= first_usable
       || disk->dev->length < last_usable)
@@ -1192,7 +1193,7 @@ _generate_header (const PedDisk *disk, int alternate, uint32_t ptes_crc,
     {
       gpt->MyLBA = PED_CPU_TO_LE64 (1);
       gpt->AlternateLBA = PED_CPU_TO_LE64 (gpt_disk_data->AlternateLBA);
-      gpt->PartitionEntryLBA = PED_CPU_TO_LE64 (2);
+      gpt->PartitionEntryLBA = PED_CPU_TO_LE64 (disk->dev->pte_lba);
     }
 
   gpt->FirstUsableLBA = PED_CPU_TO_LE64 (gpt_disk_data->data_area.start);
@@ -1284,7 +1285,7 @@ gpt_write (const PedDisk *disk)
   free (pth_raw);
   if (!write_ok)
     goto error_free_ptes;
-  if (!ped_device_write (disk->dev, ptes, 2, ptes_sectors))
+  if (!ped_device_write (disk->dev, ptes, disk->dev->pte_lba, ptes_sectors))
     goto error_free_ptes;
 
   /* Write Alternate PTH & PTEs */
@@ -1962,7 +1963,7 @@ gpt_get_max_primary_partition_count (const PedDisk *disk)
  *
  * The number of possible partitions or supported partitions is:
  * SP = FirstUsableLBA*Blocksize - 2*Blocksize / SizeOfPartitionEntry
- * SP = Blocksize(FirstusableLBA - 2) / SizeOfPartitoinEntry
+ * SP = Blocksize(FirstusableLBA - PartitionEntryLBA) / SizeOfPartitoinEntry
  */
 static bool
 gpt_get_max_supported_partition_count (const PedDisk *disk, int *max_n)
@@ -1986,7 +1987,7 @@ gpt_get_max_supported_partition_count (const PedDisk *disk, int *max_n)
         = PED_CPU_TO_LE32 (sizeof (GuidPartitionEntry_t));
     }
 
-  *max_n = (disk->dev->sector_size * (PED_LE64_TO_CPU (pth->FirstUsableLBA) - 2)
+  *max_n = (disk->dev->sector_size * (PED_LE64_TO_CPU (pth->FirstUsableLBA) - PED_LE64_TO_CPU (pth->PartitionEntryLBA))
             / PED_LE32_TO_CPU (pth->SizeOfPartitionEntry));
   pth_free (pth);
   return true;
diff --git a/parted/parted.c b/parted/parted.c
index a9426c4..cfd5de8 100644
--- a/parted/parted.c
+++ b/parted/parted.c
@@ -511,6 +511,7 @@ do_mklabel (PedDevice** dev, PedDisk** diskp)
 {
         PedDisk*                disk;
         const PedDiskType*      type = NULL;
+        int                     pte_lba = 2;
 
         if (*diskp)
                 disk = *diskp;
@@ -524,6 +525,11 @@ do_mklabel (PedDevice** dev, PedDisk** diskp)
         if (!command_line_get_disk_type (_("New disk label type?"), &type))
                 goto error;
 
+        if (!command_line_get_integer (_("Starting LBA of partition entry array?"), &pte_lba))
+                goto error;
+
+        (*dev)->pte_lba = pte_lba;
+
         if (disk) {
                 if (!_disk_warn_busy (disk))
                         goto error;
-- 
2.7.3