[sheepdog] [PATCH stable-0.7] dog: let "dog vdi cache" subcommands parse arguments in a correct manner

[Hitoshi Mitake]

Current subcommands of "dog vdi cache" can cause segmentation faults
because they don't check an index of argv.

Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix at gmail.com>

Conflicts:
	dog/vdi.c
Conflicts were resolved by Hitoshi Mitake.

Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
---
 dog/vdi.c |   20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/dog/vdi.c b/dog/vdi.c
index f13a31f..f4fbc67 100644
--- a/dog/vdi.c
+++ b/dog/vdi.c
@@ -1991,11 +1991,19 @@ out:
 
 static int vdi_cache_flush(int argc, char **argv)
 {
-	const char *vdiname = argv[optind++];
+	const char *vdiname;
 	struct sd_req hdr;
 	uint32_t vid;
 	int ret = EXIT_SUCCESS;
 
+	if (optind < argc)
+		vdiname = argv[optind++];
+	else {
+		sd_err("please specify VDI name");
+		ret = EXIT_FAILURE;
+		goto out;
+	}
+
 	ret = find_vdi_name(vdiname, vdi_cmd_data.snapshot_id,
 			    vdi_cmd_data.snapshot_tag, &vid, 0);
 	if (ret < 0) {
@@ -2018,11 +2026,19 @@ out:
 
 static int vdi_cache_delete(int argc, char **argv)
 {
-	const char *vdiname = argv[optind++];
+	const char *vdiname;
 	struct sd_req hdr;
 	uint32_t vid;
 	int ret = EXIT_SUCCESS;
 
+	if (optind < argc)
+		vdiname = argv[optind++];
+	else {
+		sd_err("please specify VDI name");
+		ret = EXIT_FAILURE;
+		goto out;
+	}
+
 	ret = find_vdi_name(vdiname, vdi_cmd_data.snapshot_id,
 			    vdi_cmd_data.snapshot_tag, &vid, 0);
 	if (ret < 0) {
-- 
1.7.10.4