Better check if argc is 0 because argv[0] is later used.

sandbox/linux/suid/sandbox.c

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // http://code.google.com/p/chromium/wiki/LinuxSUIDSandbox
 
 #define _GNU_SOURCE
 #include <asm/unistd.h>
 #include <errno.h>
 #include <fcntl.h>
@@ skipping 363 matching lines @@
     }
 
     free(saved_envvar);
   }
 
   return true;
 }
 
 int main(int argc, char **argv) {
   if (argc <= 1) {
+    if (argc == 0) {
+      return 1;
+    }
+
     fprintf(stderr, "Usage: %s <renderer process> <args...>\n", argv[0]);
     return 1;
   }
 
   // In the SUID sandbox, if we succeed in calling MoveToNewNamespaces()
   // below, then the zygote and all the renderers are in an alternate PID
   // namespace and do not know their real PIDs. As such, they report the wrong
   // PIDs to the task manager.
   //
   // To fix this, when the zygote spawns a new renderer, it gives the renderer
@@ skipping 38 matching lines @@
   if (!DropRoot())
     return 1;
   if (!SetupChildEnvironment())
     return 1;
 
   execv(argv[1], &argv[1]);
   FatalError("execv failed");
 
   return 1;
 }