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::StringPrintf;
32
ExecAndReturnCode(std::vector<std::string> & arg_vector,std::string * error_msg)33 int ExecAndReturnCode(std::vector<std::string>& arg_vector, std::string* error_msg) {
34 const std::string command_line(android::base::Join(arg_vector, ' '));
35 CHECK_GE(arg_vector.size(), 1U) << command_line;
36
37 // Convert the args to char pointers.
38 const char* program = arg_vector[0].c_str();
39 std::vector<char*> args;
40 for (size_t i = 0; i < arg_vector.size(); ++i) {
41 const std::string& arg = arg_vector[i];
42 char* arg_str = const_cast<char*>(arg.c_str());
43 CHECK(arg_str != nullptr) << i;
44 args.push_back(arg_str);
45 }
46 args.push_back(nullptr);
47
48 // fork and exec
49 pid_t pid = fork();
50 if (pid == 0) {
51 // no allocation allowed between fork and exec
52
53 // change process groups, so we don't get reaped by ProcessManager
54 setpgid(0, 0);
55
56 // (b/30160149): protect subprocesses from modifications to LD_LIBRARY_PATH, etc.
57 // Use the snapshot of the environment from the time the runtime was created.
58 char** envp = (Runtime::Current() == nullptr) ? nullptr : Runtime::Current()->GetEnvSnapshot();
59 if (envp == nullptr) {
60 execv(program, &args[0]);
61 } else {
62 execve(program, &args[0], envp);
63 }
64 PLOG(ERROR) << "Failed to execve(" << command_line << ")";
65 // _exit to avoid atexit handlers in child.
66 _exit(1);
67 } else {
68 if (pid == -1) {
69 *error_msg = StringPrintf("Failed to execv(%s) because fork failed: %s",
70 command_line.c_str(), strerror(errno));
71 return -1;
72 }
73
74 // wait for subprocess to finish
75 int status = -1;
76 pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
77 if (got_pid != pid) {
78 *error_msg = StringPrintf("Failed after fork for execv(%s) because waitpid failed: "
79 "wanted %d, got %d: %s",
80 command_line.c_str(), pid, got_pid, strerror(errno));
81 return -1;
82 }
83 if (WIFEXITED(status)) {
84 return WEXITSTATUS(status);
85 }
86 return -1;
87 }
88 }
89
Exec(std::vector<std::string> & arg_vector,std::string * error_msg)90 bool Exec(std::vector<std::string>& arg_vector, std::string* error_msg) {
91 int status = ExecAndReturnCode(arg_vector, error_msg);
92 if (status != 0) {
93 const std::string command_line(android::base::Join(arg_vector, ' '));
94 *error_msg = StringPrintf("Failed execv(%s) because non-0 exit status",
95 command_line.c_str());
96 return false;
97 }
98 return true;
99 }
100
101 } // namespace art
102