gpsmon: fix NULL pointer dereference.

Thanks to a report from <alexc@sbrella.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/gpsmon.c b/gpsmon.c
index a495473d..941daec3 100644
--- a/gpsmon.c
+++ b/gpsmon.c
@@ -1298,9 +1298,16 @@ int main(int argc, char **argv)
     }
 
     if (serial) {
-	(void) strlcpy(session.gpsdata.dev.path,
-		       source.device,
-		       sizeof(session.gpsdata.dev.path));
+        if (NULL == source.device) {
+            /* this can happen with "gpsmon /dev:dd" */
+	    (void) strlcpy(session.gpsdata.dev.path,
+			   argv[optind],
+			   sizeof(session.gpsdata.dev.path));
+        } else {
+	    (void) strlcpy(session.gpsdata.dev.path,
+			   source.device,
+			   sizeof(session.gpsdata.dev.path));
+        }
     } else {
 	if (strstr(source.server, "//") == 0)
 	    (void) strlcpy(session.gpsdata.dev.path,