[PATCH v5 09/16] partmap/gpt: Add grub_gpt_partition_get_label()

[Vitaly Kuzmichev]

This patch adds a function to provide partition PARTLABEL on GPT
formatted disks by extracting first 72 bytes of UTF-16LE encoded
partition name from corresponding GPT entry and converting it
to UTF-8 string.

Signed-off-by: Vitaly Kuzmichev <vitaly.kuzmichev@rtsoft.de>
---
 grub-core/partmap/gpt.c      | 36 ++++++++++++++++++++++++++++++++++++
 include/grub/gpt_partition.h |  3 +++
 2 files changed, 39 insertions(+)

diff --git a/grub-core/partmap/gpt.c b/grub-core/partmap/gpt.c
index b43f46987..451ca2440 100644
--- a/grub-core/partmap/gpt.c
+++ b/grub-core/partmap/gpt.c
@@ -50,6 +50,42 @@ static struct grub_partition_map grub_gpt_partition_map;
 
 
 
+static char *
+get_utf8 (const char *in, grub_size_t len)
+{
+  return (char *) grub_utf16_to_utf8_alloc (in,
+                                           len / sizeof (grub_uint16_t),
+                                           UTF16_LE);
+}
+
+char *
+grub_gpt_partition_get_label (grub_device_t dev)
+{
+  struct grub_gpt_partentry gptdata;
+  grub_disk_t disk;
+  grub_partition_t pt;
+  char *part_label = NULL;
+
+  if (dev && dev->disk && dev->disk->partition && 
dev->disk->partition->partmap)
+    {
+      pt = dev->disk->partition;
+      if (grub_strcmp (pt->partmap->name, "gpt") == 0)
+       {
+         disk = grub_disk_open (dev->disk->name);
+         if (disk && grub_disk_read (disk, pt->offset, pt->index,
+                                     sizeof (gptdata), &gptdata) == 0)
+           part_label = get_utf8 (gptdata.name, sizeof (gptdata.name));
+         if (!part_label)
+           grub_error_push ();
+         grub_disk_close (disk);
+         if (!part_label)
+           grub_error_pop ();
+       }
+    }
+
+  return part_label;
+}
+
 char *
 grub_gpt_partition_get_uuid (grub_device_t dev)
 {
diff --git a/include/grub/gpt_partition.h b/include/grub/gpt_partition.h
index e52834ac2..8917f40ac 100644
--- a/include/grub/gpt_partition.h
+++ b/include/grub/gpt_partition.h
@@ -74,6 +74,9 @@ grub_gpt_partition_map_iterate (grub_disk_t disk,
                                grub_partition_iterate_hook_t hook,
                                void *hook_data);
 
+char *
+grub_gpt_partition_get_label (grub_device_t dev);
+
 char *
 grub_gpt_partition_get_uuid (grub_device_t dev);
 
-- 
2.34.1