1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "exec_utils.h" 18 19 #include <sys/types.h> 20 #include <sys/wait.h> 21 #include <string> 22 #include <vector> 23 24 #include "android-base/stringprintf.h" 25 #include "android-base/strings.h" 26 27 #include "runtime.h" 28 29 namespace art { 30 31 using android::base::StringAppendF; 32 using android::base::StringPrintf; 33 34 int ExecAndReturnCode(std::vector<std::string>& arg_vector, std::string* error_msg) { 35 const std::string command_line(android::base::Join(arg_vector, ' ')); 36 CHECK_GE(arg_vector.size(), 1U) << command_line; 37 38 // Convert the args to char pointers. 39 const char* program = arg_vector[0].c_str(); 40 std::vector<char*> args; 41 for (size_t i = 0; i < arg_vector.size(); ++i) { 42 const std::string& arg = arg_vector[i]; 43 char* arg_str = const_cast<char*>(arg.c_str()); 44 CHECK(arg_str != nullptr) << i; 45 args.push_back(arg_str); 46 } 47 args.push_back(nullptr); 48 49 // fork and exec 50 pid_t pid = fork(); 51 if (pid == 0) { 52 // no allocation allowed between fork and exec 53 54 // change process groups, so we don't get reaped by ProcessManager 55 setpgid(0, 0); 56 57 // (b/30160149): protect subprocesses from modifications to LD_LIBRARY_PATH, etc. 58 // Use the snapshot of the environment from the time the runtime was created. 59 char** envp = (Runtime::Current() == nullptr) ? nullptr : Runtime::Current()->GetEnvSnapshot(); 60 if (envp == nullptr) { 61 execv(program, &args[0]); 62 } else { 63 execve(program, &args[0], envp); 64 } 65 PLOG(ERROR) << "Failed to execve(" << command_line << ")"; 66 // _exit to avoid atexit handlers in child. 67 _exit(1); 68 } else { 69 if (pid == -1) { 70 *error_msg = StringPrintf("Failed to execv(%s) because fork failed: %s", 71 command_line.c_str(), strerror(errno)); 72 return -1; 73 } 74 75 // wait for subprocess to finish 76 int status = -1; 77 pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0)); 78 if (got_pid != pid) { 79 *error_msg = StringPrintf("Failed after fork for execv(%s) because waitpid failed: " 80 "wanted %d, got %d: %s", 81 command_line.c_str(), pid, got_pid, strerror(errno)); 82 return -1; 83 } 84 if (WIFEXITED(status)) { 85 return WEXITSTATUS(status); 86 } 87 return -1; 88 } 89 } 90 91 bool Exec(std::vector<std::string>& arg_vector, std::string* error_msg) { 92 int status = ExecAndReturnCode(arg_vector, error_msg); 93 if (status != 0) { 94 const std::string command_line(android::base::Join(arg_vector, ' ')); 95 *error_msg = StringPrintf("Failed execv(%s) because non-0 exit status", 96 command_line.c_str()); 97 return false; 98 } 99 return true; 100 } 101 102 } // namespace art 103
