[PATCH i-g-t v6 3/6] tools/vbt_decode: validate DEVICE env var

["Michał Grzelak" <michal.grzelak@intel.com>]

On error, strotoul() returns converted value of longest substring
spanning from beginning. Check if device ID input via DEVICE env var is
valid. Show it and return if it is not.

v2->v3
- show whole invalid DEVICE env var (Jani)

Signed-off-by: Michał Grzelak <michal.grzelak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
---
 tools/intel_vbt_decode.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/intel_vbt_decode.c b/tools/intel_vbt_decode.c
index 9f059bfbbb..80e0db2814 100644
--- a/tools/intel_vbt_decode.c
+++ b/tools/intel_vbt_decode.c
@@ -4326,8 +4326,14 @@ int main(int argc, char **argv)
 
 	if (!context.devid) {
 		const char *devid_string = getenv("DEVICE");
-		if (devid_string)
-			context.devid = strtoul(devid_string, NULL, 16);
+		if (devid_string) {
+			context.devid = strtoul(devid_string, &endp, 16);
+			if (!context.devid || *endp) {
+				fprintf(stderr, "invalid devid '%s' in DEVICE environment variable\n",
+					devid_string);
+				return EXIT_FAILURE;
+			}
+		}
 	}
 	if (!context.devid)
 		context.devid = get_device_id(VBIOS, size);
-- 
2.45.2