Linux Sandbox: add resource limits to NaCl

sandbox/linux/services/resource_limits.cc

Index: sandbox/linux/services/resource_limits.cc
diff --git a/sandbox/linux/services/resource_limits.cc b/sandbox/linux/services/resource_limits.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1ec11295d1d4eb116369edcca7b1a1de40679f10
--- /dev/null
+++ b/sandbox/linux/services/resource_limits.cc
@@ -0,0 +1,26 @@
+// Copyright 2015 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.
+
+#include "sandbox/linux/services/resource_limits.h"
+
+#include <sys/resource.h>
+#include <sys/time.h>
+
+#include <algorithm>
+
+namespace sandbox {
+
+// static
+bool ResourceLimits::Lower(int resource, rlim_t limit) {
+  struct rlimit old_rlimit;
+  if (getrlimit(resource, &old_rlimit))
+    return false;
+  // Make sure we don't raise the existing limit.
+  const struct rlimit new_rlimit = {std::min(old_rlimit.rlim_cur, limit),
+                                    std::min(old_rlimit.rlim_max, limit)};
+  int rc = setrlimit(resource, &new_rlimit);
+  return rc == 0;
+}
+
+}  // namespace sandbox