system_unittest.cc

// system_unittest.cpp
// Copyright (C) 2017 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Test system.[ch] module code using gtest.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <gtest/gtest.h>

#include "system.h"

namespace {

// A random path that really really should not exist on the host.
const char kNoSuchDir[] = "/.x/..x/...x/path/should/not/exist/";

// Return a temp filename in the cwd that this test can manipulate.
// It will not exist when it returns, and the user has to free the memory.
char *get_temp_path() {
  char *path = strdup("minijail.tests.XXXXXX");
  if (!path)
    return nullptr;

  // Just create the temp path.
  int fd = mkstemp(path);
  if (fd < 0)
    return nullptr;
  close(fd);
  unlink(path);

  return path;
}

}  // namespace

// Sanity check for the cap range.
TEST(get_last_valid_cap, basic) {
  unsigned int cap = get_last_valid_cap();

  // We pick 35 as it's been that since at least v3.0.
  // If this test is run on older kernels, it might fail.
  EXPECT_GE(cap, 35u);

  // Pick a really large number that we probably won't hit for a long time.
  // It helps that caps are bitfields.
  EXPECT_LT(cap, 128u);
}

// Might be useful to figure out the return value, but for now,
// just make sure it doesn't crash?
TEST(cap_ambient_supported, smoke) {
  cap_ambient_supported();
}

// Invalid indexes should return errors, not crash.
TEST(setup_pipe_end, bad_index) {
  EXPECT_LT(setup_pipe_end(nullptr, 2), 0);
  EXPECT_LT(setup_pipe_end(nullptr, 3), 0);
  EXPECT_LT(setup_pipe_end(nullptr, 4), 0);
}

// Verify getting the first fd works.
TEST(setup_pipe_end, index0) {
  int fds[2];
  EXPECT_EQ(0, pipe(fds));
  // This should close fds[1] and return fds[0].
  EXPECT_EQ(fds[0], setup_pipe_end(fds, 0));
  // Use close() to verify open/close state.
  EXPECT_EQ(-1, close(fds[1]));
  EXPECT_EQ(0, close(fds[0]));
}

// Verify getting the second fd works.
TEST(setup_pipe_end, index1) {
  int fds[2];
  EXPECT_EQ(0, pipe(fds));
  // This should close fds[0] and return fds[1].
  EXPECT_EQ(fds[1], setup_pipe_end(fds, 1));
  // Use close() to verify open/close state.
  EXPECT_EQ(-1, close(fds[0]));
  EXPECT_EQ(0, close(fds[1]));
}

// Invalid indexes should return errors, not crash.
TEST(setup_and_dupe_pipe_end, bad_index) {
  EXPECT_LT(setup_and_dupe_pipe_end(nullptr, 2, -1), 0);
  EXPECT_LT(setup_and_dupe_pipe_end(nullptr, 3, -1), 0);
  EXPECT_LT(setup_and_dupe_pipe_end(nullptr, 4, -1), 0);
}

// An invalid path should return an error.
TEST(write_pid_to_path, bad_path) {
  EXPECT_NE(0, write_pid_to_path(0, kNoSuchDir));
}

// Make sure we can write a pid to the file.
TEST(write_pid_to_path, basic) {
  char *path = get_temp_path();
  ASSERT_NE(nullptr, path);

  EXPECT_EQ(0, write_pid_to_path(1234, path));
  FILE *fp = fopen(path, "re");
  unlink(path);
  EXPECT_NE(nullptr, fp);
  char data[5];
  EXPECT_EQ(5u, fread(data, 1, sizeof(data), fp));
  fclose(fp);
  EXPECT_EQ(0, strcmp(data, "1234\n"));
}