Simplified unit testing of sandboxing code.

sandbox/linux/tests/unit_tests.cc

Index: sandbox/linux/tests/unit_tests.cc
diff --git a/sandbox/linux/tests/unit_tests.cc b/sandbox/linux/tests/unit_tests.cc
index 2e24d8c07c8ffa27386099f439bbda83b1894e2c..105c45bc58926f9a36a81a4bd527745aff573b99 100644
--- a/sandbox/linux/tests/unit_tests.cc
+++ b/sandbox/linux/tests/unit_tests.cc
@@ -2,13 +2,76 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "testing/gtest/include/gtest/gtest.h"
-int main(int argc, char *argv[]) {
-  testing::InitGoogleTest(&argc, argv);
-  // Always go through re-execution for death tests.
-  // This makes gtest only marginally slower for us and has the
-  // additional side effect of getting rid of gtest warnings about fork()
-  // safety.
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  return RUN_ALL_TESTS();
+#include <stdio.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+
+#include "base/file_util.h"
+#include "sandbox/linux/tests/unit_tests.h"
+
+namespace sandbox {
+
+static const int kExpectedValue = 42;
+
+void UnitTests::RunTestInProcess(UnitTests::Test test, void *arg) {
+  // Runs a test in a sub-process. This is necessary for most of the code
+  // in the BPF sandbox, as it potentially makes global state changes and as
+  // it also tends to raise fatal errors, if the code has been used in an
+  // insecure manner.
+  int fds[2];
+  ASSERT_EQ(0, pipe(fds));
+
+  pid_t pid;
+  ASSERT_LE(0, (pid = fork()));
+  if (!pid) {
+    // In child process
+    // Redirect stderr to our pipe. This way, we can capture all error
+    // messages, if we decide we want to do so in our tests.
+    SANDBOX_ASSERT(dup2(fds[1], 2) == 2);
+    SANDBOX_ASSERT(!close(fds[0]));
+    SANDBOX_ASSERT(!close(fds[1]));
+
+    // Disable core files. They are not very useful for our individual test
+    // cases.
+    struct rlimit no_core = { 0 };
+    setrlimit(RLIMIT_CORE, &no_core);
+
+    test(arg);
+    _exit(kExpectedValue);
+  }
+
+  (void)HANDLE_EINTR(close(fds[1]));
+  std::vector<char> msg;
+  ssize_t rc;
+  do {
+    const unsigned int kCapacity = 256;
+    size_t len = msg.size();
+    msg.resize(len + kCapacity);
+    rc = HANDLE_EINTR(read(fds[0], &msg[len], kCapacity));
+    msg.resize(len + std::max(rc, static_cast<ssize_t>(0)));
+  } while (rc > 0);
+  std::string details;
+  if (!msg.empty()) {
+    details = "Actual test failure: " + std::string(msg.begin(), msg.end());
+  }
+  (void)HANDLE_EINTR(close(fds[0]));
+
+  int status = 0;
+  int waitpid_returned = HANDLE_EINTR(waitpid(pid, &status, 0));
+  ASSERT_EQ(pid, waitpid_returned) << details;
+  bool subprocess_terminated_normally = WIFEXITED(status);
+  ASSERT_TRUE(subprocess_terminated_normally) << details;
+  int subprocess_exit_status = WEXITSTATUS(status);
+  ASSERT_EQ(kExpectedValue, subprocess_exit_status) << details;
+  bool subprocess_exited_but_printed_messages = !msg.empty();
+  EXPECT_FALSE(subprocess_exited_but_printed_messages) << details;
 }
+
+void UnitTests::AssertionFailure(const char *expr, const char *file,
+                                 int line) {
+  fprintf(stderr, "%s:%d:%s", file, line, expr);
+  fflush(stderr);
+  _exit(1);
+}
+
+}  // namespace