Add unit test to check for broker FD leak

sandbox/linux/services/broker_process_unittest.cc

Index: sandbox/linux/services/broker_process_unittest.cc
diff --git a/sandbox/linux/services/broker_process_unittest.cc b/sandbox/linux/services/broker_process_unittest.cc
index 7f1a685fe11cbac269e0157e7a0c6825756d3f44..8d3068d87ada2700daf6b95e4a7fe99393a00352 100644
--- a/sandbox/linux/services/broker_process_unittest.cc
+++ b/sandbox/linux/services/broker_process_unittest.cc
@@ -21,6 +21,7 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/posix/eintr_wrapper.h"
+#include "base/posix/unix_domain_socket_linux.h"
 #include "sandbox/linux/tests/test_utils.h"
 #include "sandbox/linux/tests/unit_tests.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -434,4 +435,37 @@ TEST(BrokerProcess, OpenComplexFlagsNoClientCheck) {
   // expected.
 }
 
+SANDBOX_DEATH_TEST(BrokerProcess, RecvMsgDescriptorLeak, DEATH_EXIT_CODE(0)) {
+  // Find the lowest available file descriptor currently.
+  const int min_fd = dup(STDIN_FILENO);
+  SANDBOX_ASSERT(min_fd >= 0);
+  SANDBOX_ASSERT(0 == IGNORE_EINTR(close(min_fd)));
+
+  // Lower our file descriptor limit to just above the current limit so we can
+  // test for descriptor leaks easier.
+  const unsigned kExtraFiles = 8;
+  const struct rlimit new_rlim = {min_fd + kExtraFiles, min_fd + kExtraFiles};
+  SANDBOX_ASSERT(0 == setrlimit(RLIMIT_NOFILE, &new_rlim));
+
+  const char kCpuInfo[] = "/proc/cpuinfo";
+  std::vector<std::string> read_whitelist;
+  read_whitelist.push_back(kCpuInfo);
+
+  BrokerProcess open_broker(EPERM, read_whitelist, std::vector<std::string>());
+  SANDBOX_ASSERT(open_broker.Init(base::Bind(&NoOpCallback)));
+
+  static const char kBogus[] = "not a pickle";
+  const std::vector<int> fds(1, STDIN_FILENO);
+
+  for (unsigned i = 0; i < kExtraFiles; ++i) {
+    SANDBOX_ASSERT(UnixDomainSocket::SendMsg(
+        open_broker.ipc_socketpair(), kBogus, sizeof(kBogus), fds));
+  }
+
+  const int fd = open_broker.Open(kCpuInfo, O_RDONLY);
+  SANDBOX_ASSERT(fd >= 0);
+  SANDBOX_ASSERT(0 == IGNORE_EINTR(close(fd)));
+  _exit(0);
+}
+
 }  // namespace sandbox