[minijail] stop parsing at first non-opt arg

BUG=chromium-os:35122
TEST=security_Minijail0,adhoc
Running minijail with different stop arguments should work:
$ /sbin/minijail0 /bin/ls -u INVALID_USER
/bin/ls: cannot access INVALID_USER: No such file or directory
$ /sbin/minijail0 -u bin /bin/ls -g INVALID_GROUP
/bin/ls: cannot access INVALID_GROUP: No such file or directory
$ /sbin/minijail0 -u bin -g bin /bin/echo -x
-x

Change-Id: I2d7ced270ddecd7a5ee3b99c5416e3982f5dc112
Signed-off-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/41767
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
1 file changed