// Copyright 2011 Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
//   notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the distribution.
// * Neither the name of Google Inc. nor the names of its contributors
//   may be used to endorse or promote products derived from this software
//   without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

extern "C" {
#include <sys/stat.h>

#include <unistd.h>
}

#include <cstdlib>
#include <fstream>
#include <iostream>
#include <sstream>

#include "utils/defs.hpp"
#include "utils/env.hpp"
#include "utils/fs/operations.hpp"
#include "utils/fs/path.hpp"
#include "utils/optional.ipp"

namespace fs = utils::fs;

using utils::optional;


namespace {


/// Logs an error message and exits the test with an error code.
///
/// \param str The error message to log.
static void
fail(const char* str)
{
    std::cerr << str << '\n';
    std::exit(EXIT_FAILURE);
}


/// A test case that crashes.
static void
test_crash(void)
{
    std::abort();
}


/// A test case that exits with a non-zero exit code, and not 1.
static void
test_fail(void)
{
    std::exit(8);
}


/// A test case that passes.
static void
test_pass(void)
{
}


/// A test case that spawns a subchild that gets stuck.
///
/// This test case is used by the caller to validate that the whole process tree
/// is terminated when the test case is killed.
static void
test_spawn_blocking_child(void)
{
    pid_t pid = ::fork();
    if (pid == -1)
        fail("Cannot fork subprocess");
    else if (pid == 0) {
        for (;;)
            ::pause();
    } else {
        const fs::path name = fs::path(utils::getenv("CONTROL_DIR").get()) /
            "pid";
        std::ofstream pidfile(name.c_str());
        if (!pidfile)
            fail("Failed to create the pidfile");
        pidfile << pid;
        pidfile.close();
    }
}


/// A test case that times out.
///
/// Note that the timeout is defined in the Kyuafile, as the plain interface has
/// no means for test programs to specify this by themselves.
static void
test_timeout(void)
{
    ::sleep(10);
    const fs::path control_dir = fs::path(utils::getenv("CONTROL_DIR").get());
    std::ofstream file((control_dir / "cookie").c_str());
    if (!file)
        fail("Failed to create the control cookie");
    file.close();
}


/// A test case that performs basic checks on the runtime environment.
///
/// If the runtime environment does not look clean (according to the rules in
/// the Kyua runtime properties), the test fails.
static void
test_validate_isolation(void)
{
    if (utils::getenv("HOME").get() == "fake-value")
        fail("HOME not reset");
    if (utils::getenv("LANG"))
        fail("LANG not unset");
}


}  // anonymous namespace


/// Entry point to the test program.
///
/// The caller can select which test case to run by defining the TEST_CASE
/// environment variable.  This is not "standard", in the sense this is not a
/// generic property of the plain test case interface.
///
/// \todo It may be worth to split this binary into separate, smaller binaries,
/// one for every "test case".  We use this program as a dispatcher for
/// different "main"s, the only reason being to keep the amount of helper test
/// programs to a minimum.  However, putting this each function in its own
/// binary could simplify many other things.
///
/// \param argc The number of CLI arguments.
/// \param unused_argv The CLI arguments themselves.  These are not used because
///     Kyua will not pass any arguments to the plain test program.
int
main(int argc, char** UTILS_UNUSED_PARAM(argv))
{
    if (argc != 1) {
        std::cerr << "No arguments allowed; select the test case with the "
            "TEST_CASE variable";
        return EXIT_FAILURE;
    }

    const optional< std::string > test_case_env = utils::getenv("TEST_CASE");
    if (!test_case_env) {
        std::cerr << "TEST_CASE not defined";
        return EXIT_FAILURE;
    }
    const std::string& test_case = test_case_env.get();

    if (test_case == "crash")
        test_crash();
    else if (test_case == "fail")
        test_fail();
    else if (test_case == "pass")
        test_pass();
    else if (test_case == "spawn_blocking_child")
        test_spawn_blocking_child();
    else if (test_case == "timeout")
        test_timeout();
    else if (test_case == "validate_isolation")
        test_validate_isolation();
    else {
        std::cerr << "Unknown test case";
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}