1 // Copyright 2015 The Kyua Authors. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above copyright 11 // notice, this list of conditions and the following disclaimer in the 12 // documentation and/or other materials provided with the distribution. 13 // * Neither the name of Google Inc. nor the names of its contributors 14 // may be used to endorse or promote products derived from this software 15 // without specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29 /// \file integration/helpers/race.cpp 30 /// Creates a file and reads it back, looking for races. 31 /// 32 /// This program should fail with high chances if it is called multiple times at 33 /// once with TEST_ENV_shared_file pointing to the same file. 34 35 extern "C" { 36 #include <sys/types.h> 37 38 #include <unistd.h> 39 } 40 41 #include <cstdlib> 42 #include <fstream> 43 #include <iostream> 44 45 #include "utils/format/macros.hpp" 46 #include "utils/fs/operations.hpp" 47 #include "utils/fs/path.hpp" 48 #include "utils/env.hpp" 49 #include "utils/optional.ipp" 50 #include "utils/stream.hpp" 51 52 namespace fs = utils::fs; 53 54 using utils::optional; 55 56 57 /// Entry point to the helper test program. 58 /// 59 /// \return EXIT_SUCCESS if no race is detected; EXIT_FAILURE otherwise. 60 int 61 main(void) 62 { 63 const optional< std::string > shared_file = utils::getenv( 64 "TEST_ENV_shared_file"); 65 if (!shared_file) { 66 std::cerr << "Environment variable TEST_ENV_shared_file not defined\n"; 67 std::exit(EXIT_FAILURE); 68 } 69 const fs::path shared_path(shared_file.get()); 70 71 if (fs::exists(shared_path)) { 72 std::cerr << "Shared file already exists; created by a concurrent " 73 "test?"; 74 std::exit(EXIT_FAILURE); 75 } 76 77 const std::string contents = F("%s") % ::getpid(); 78 79 std::ofstream output(shared_path.c_str()); 80 if (!output) { 81 std::cerr << "Failed to create shared file; conflict with a concurrent " 82 "test?"; 83 std::exit(EXIT_FAILURE); 84 } 85 output << contents; 86 output.close(); 87 88 ::usleep(10000); 89 90 const std::string read_contents = utils::read_file(shared_path); 91 if (read_contents != contents) { 92 std::cerr << "Shared file contains unexpected contents; modified by a " 93 "concurrent test?"; 94 std::exit(EXIT_FAILURE); 95 } 96 97 fs::unlink(shared_path); 98 std::exit(EXIT_SUCCESS); 99 } 100