[PATCH] cmd: gpt: Add option to write GPT partitions to environment variable

[Farhan Ali <farhan.ali@broadcom.com>]

This change would enhance the existing 'gpt read' command to allow
(optionally) writing of the read GPT partitions to an environment
variable. This would allow users to easily change the partition
settings and then simply reuse the variable in the 'gpt write' and
'gpt verify' commands.

Signed-off-by: Farhan Ali <farhan.ali@broadcom.com>
---
Cc: Simon Glass <sjg@chromium.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Corneliu Doban <cdoban@broadcom.com>
Cc: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>

 cmd/gpt.c | 46 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 38 insertions(+), 8 deletions(-)

diff --git a/cmd/gpt.c b/cmd/gpt.c
index 76a95ad..12d0551 100644
--- a/cmd/gpt.c
+++ b/cmd/gpt.c
@@ -350,17 +350,46 @@ static int get_gpt_info(struct blk_desc *dev_desc)
 }
 
 /* a wrapper to test get_gpt_info */
-static int do_get_gpt_info(struct blk_desc *dev_desc)
+static int do_get_gpt_info(struct blk_desc *dev_desc, char * const namestr)
 {
-	int ret;
+	int numparts;
+
+	numparts = get_gpt_info(dev_desc);
+
+	if (numparts > 0) {
+		if (namestr) {
+			char disk_guid[UUID_STR_LEN + 1];
+			char *partitions_list;
+			int partlistlen;
+			int ret = -1;
+
+			ret = get_disk_guid(dev_desc, disk_guid);
+			if (ret < 0)
+				return ret;
+
+			partlistlen = calc_parts_list_len(numparts);
+			partitions_list = malloc(partlistlen);
+			if (!partitions_list) {
+				del_gpt_info();
+				return -ENOMEM;
+			}
+			memset(partitions_list, '\0', partlistlen);
+
+			ret = create_gpt_partitions_list(numparts, disk_guid,
+							 partitions_list);
+			if (ret < 0)
+				printf("Error: Could not create partition list string!\n");
+			else
+				env_set(namestr, partitions_list);
 
-	ret = get_gpt_info(dev_desc);
-	if (ret > 0) {
-		print_gpt_info();
+			free(partitions_list);
+		} else {
+			print_gpt_info();
+		}
 		del_gpt_info();
 		return 0;
 	}
-	return ret;
+	return numparts;
 }
 #endif
 
@@ -982,7 +1011,7 @@ static int do_gpt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 		ret = do_disk_guid(blk_dev_desc, argv[4]);
 #ifdef CONFIG_CMD_GPT_RENAME
 	} else if (strcmp(argv[1], "read") == 0) {
-		ret = do_get_gpt_info(blk_dev_desc);
+		ret = do_get_gpt_info(blk_dev_desc, argv[4]);
 	} else if ((strcmp(argv[1], "swap") == 0) ||
 		   (strcmp(argv[1], "rename") == 0)) {
 		ret = do_rename_gpt_parts(blk_dev_desc, argv[1], argv[4], argv[5]);
@@ -1028,8 +1057,9 @@ U_BOOT_CMD(gpt, CONFIG_SYS_MAXARGS, 1, do_gpt,
 	" gpt guid mmc 0 varname\n"
 #ifdef CONFIG_CMD_GPT_RENAME
 	"gpt partition renaming commands:\n"
-	" gpt read <interface> <dev>\n"
+	" gpt read <interface> <dev> [<varname>]\n"
 	"    - read GPT into a data structure for manipulation\n"
+	"    - read GPT partitions into environment variable\n"
 	" gpt swap <interface> <dev> <name1> <name2>\n"
 	"    - change all partitions named name1 to name2\n"
 	"      and vice-versa\n"
-- 
1.8.3.1