Add a comment about waitpid, suggested by espie@.

diff --git a/usr.bin/file/sandbox.c b/usr.bin/file/sandbox.c
index 2295a53..a4d42cf 100644 (file)
--- a/usr.bin/file/sandbox.c
+++ b/usr.bin/file/sandbox.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sandbox.c,v 1.3 2015/04/30 14:16:49 nicm Exp $ */
+/* $OpenBSD: sandbox.c,v 1.4 2015/04/30 14:30:53 nicm Exp $ */
 
 /*
  * Copyright (c) 2015 Nicholas Marriott <nicm@openbsd.org>
@@ -116,6 +116,11 @@ sandbox_fork(const char *user)
                return (sandbox_child(user));
        }
 
+       /*
+        * Wait for the child to stop itself with SIGSTOP before assigning the
+        * policy, before that it might still be calling syscalls the policy
+        * would block.
+        */
        do {
                pid = waitpid(pid, &status, WUNTRACED);
        } while (pid == -1 && errno == EINTR);