9 files changed, 58 insertions, 4 deletions

diff --git a/libblkid/docs/libblkid-sections.txt b/libblkid/docs/libblkid-sections.txt
index 511fc30c4..265bfcaa1 100644
--- a/libblkid/docs/libblkid-sections.txt
+++ b/libblkid/docs/libblkid-sections.txt
@@ -98,6 +98,7 @@ blkid_partlist_numof_partitions
 blkid_partlist_devno_to_partition
 blkid_partlist_get_table
 <SUBSECTION>
+blkid_parttable_get_id
 blkid_parttable_get_offset
 blkid_parttable_get_parent
 blkid_parttable_get_type
diff --git a/libblkid/samples/partitions.c b/libblkid/samples/partitions.c
index 3b5273649..fe0ad4827 100644
--- a/libblkid/samples/partitions.c
+++ b/libblkid/samples/partitions.c
@@ -48,11 +48,12 @@ int main(int argc, char *argv[])
 		errx(EXIT_FAILURE, "%s: does not contains any "
 				 "known partition table\n", devname);
 
-	printf("size: %jd, sector size: %u, PT: %s, offset: %jd\n---\n",
+	printf("size: %jd, sector size: %u, PT: %s, offset: %jd, id=%s\n---\n",
 		blkid_probe_get_size(pr),
 		blkid_probe_get_sectorsize(pr),
 		blkid_parttable_get_type(root_tab),
-		blkid_parttable_get_offset(root_tab));
+		blkid_parttable_get_offset(root_tab),
+		blkid_parttable_get_id(root_tab));
 
 	/*
 	 * List partitions
diff --git a/libblkid/src/blkid.h.in b/libblkid/src/blkid.h.in
index 44f2aa7b6..68a82c356 100644
--- a/libblkid/src/blkid.h.in
+++ b/libblkid/src/blkid.h.in
@@ -391,6 +391,9 @@ extern int blkid_partition_is_primary(blkid_partition par)
 extern const char *blkid_parttable_get_type(blkid_parttable tab)
 			__ul_attribute__((warn_unused_result));
 
+extern const char *blkid_parttable_get_id(blkid_parttable tab)
+			__ul_attribute__((warn_unused_result));
+
 extern blkid_loff_t blkid_parttable_get_offset(blkid_parttable tab)
 			__ul_attribute__((warn_unused_result));
 extern blkid_partition blkid_parttable_get_parent(blkid_parttable tab)
diff --git a/libblkid/src/blkid.sym b/libblkid/src/blkid.sym
index cf2a16f94..012fe26c1 100644
--- a/libblkid/src/blkid.sym
+++ b/libblkid/src/blkid.sym
@@ -152,4 +152,5 @@ global:
 BLKID_2.23 {
 global:
 	blkid_probe_step_back;
+	blkid_parttable_get_id;
 } BLKID_2.21;
diff --git a/libblkid/src/partitions/dos.c b/libblkid/src/partitions/dos.c
index 22d2625df..58877691d 100644
--- a/libblkid/src/partitions/dos.c
+++ b/libblkid/src/partitions/dos.c
@@ -137,7 +137,7 @@ static int probe_dos_pt(blkid_probe pr,
 	blkid_partlist ls;
 	struct dos_partition *p0, *p;
 	unsigned char *data;
-	uint32_t start, size;
+	uint32_t start, size, id;
 
 	data = blkid_probe_get_sector(pr, 0);
 	if (!data)
@@ -200,6 +200,15 @@ static int probe_dos_pt(blkid_probe pr,
 	if (!tab)
 		goto err;
 
+	id = dos_parttable_id(data);
+	if (id) {
+		char buf[37];
+
+		snprintf(buf, sizeof(buf), "0x%08x", id);
+		blkid_parttable_set_id(tab, (unsigned char *) buf);
+	}
+
+
 	/* Parse primary partitions */
 	for (p = p0, i = 0; i < 4; i++, p++) {
 		blkid_partition par;
diff --git a/libblkid/src/partitions/dos.h b/libblkid/src/partitions/dos.h
index 130aa0115..d7588a856 100644
--- a/libblkid/src/partitions/dos.h
+++ b/libblkid/src/partitions/dos.h
@@ -13,7 +13,7 @@ struct dos_partition {
 #define BLKID_MSDOS_PT_OFFSET		0x1be
 
 /* assemble badly aligned little endian integer */
-static inline unsigned int assemble4le(unsigned char *p)
+static inline unsigned int assemble4le(const unsigned char *p)
 {
 	return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
 }
@@ -33,4 +33,9 @@ static inline int is_valid_mbr_signature(const unsigned char *mbr)
 	return mbr[510] == 0x55 && mbr[511] == 0xaa ? 1 : 0;
 }
 
+static inline unsigned int dos_parttable_id(const unsigned char *mbr)
+{
+	return assemble4le(&mbr[440]);
+}
+
 #endif /* BLKID_PARTITIONS_DOS_H */
diff --git a/libblkid/src/partitions/gpt.c b/libblkid/src/partitions/gpt.c
index 98e82bfd2..7288d683e 100644
--- a/libblkid/src/partitions/gpt.c
+++ b/libblkid/src/partitions/gpt.c
@@ -334,6 +334,10 @@ static int probe_gpt_pt(blkid_probe pr,
 	if (!tab)
 		goto err;
 
+	guid = h->disk_guid;
+	swap_efi_guid(&guid);
+	blkid_parttable_set_id(tab, (const unsigned char *) &guid);
+
 	ssf = blkid_probe_get_sectorsize(pr) / 512;
 
 	fu = le64_to_cpu(h->first_usable_lba);
diff --git a/libblkid/src/partitions/partitions.c b/libblkid/src/partitions/partitions.c
index d51d40744..93ec4d224 100644
--- a/libblkid/src/partitions/partitions.c
+++ b/libblkid/src/partitions/partitions.c
@@ -163,6 +163,7 @@ struct blkid_struct_parttable {
 	blkid_loff_t	offset;		/* begin of the partition table */
 	int		nparts;		/* number of partitions */
 	blkid_partition	parent;		/* parent of nested partition table */
+	char		id[37];		/* PT identifier (e.g. UUID for GPT) */
 
 	struct list_head t_tabs;	/* all tables */
 };
@@ -1002,6 +1003,33 @@ blkid_partition blkid_partlist_devno_to_partition(blkid_partlist ls, dev_t devno
 	return NULL;
 }
 
+int blkid_parttable_set_id(blkid_parttable tab, const unsigned char *id)
+{
+	if (!tab)
+		return -1;
+
+	if (strcmp(tab->type, "gpt") == 0)
+		blkid_unparse_uuid(id, tab->id, sizeof(tab->id));
+	else if (strcmp(tab->type, "dos") == 0)
+		strncpy(tab->id, (const char *) id, sizeof(tab->id));
+
+	return 0;
+}
+
+/**
+ * blkid_parttable_get_id:
+ * @tab: partition table
+ *
+ * The ID is GPT disk UUID or DOS disk ID (in hex format).
+ *
+ * Returns: partition table ID (for example GPT disk UUID) or NULL
+ */
+const char *blkid_parttable_get_id(blkid_parttable tab)
+{
+	return tab && tab->id && *tab->id ? tab->id : NULL;
+}
+
+
 int blkid_partition_set_type(blkid_partition par, int type)
 {
 	if (!par)
diff --git a/libblkid/src/partitions/partitions.h b/libblkid/src/partitions/partitions.h
index c4ccd3b65..496bd4a1e 100644
--- a/libblkid/src/partitions/partitions.h
+++ b/libblkid/src/partitions/partitions.h
@@ -9,6 +9,8 @@ extern int blkid_partitions_get_flags(blkid_probe pr);
 extern blkid_parttable blkid_partlist_new_parttable(blkid_partlist ls,
 				const char *type, blkid_loff_t offset);
 
+extern int blkid_parttable_set_id(blkid_parttable tab, const unsigned char *id);
+
 extern blkid_partition blkid_partlist_add_partition(blkid_partlist ls,
 				blkid_parttable tab,
 				blkid_loff_t start, blkid_loff_t size);