1 /*
2 ** Copyright 2019, 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 "otapreopt_utils.h"
18
19 #include <sys/types.h>
20 #include <sys/wait.h>
21 #include <unistd.h>
22
23 #include <android-base/logging.h>
24 #include <android-base/stringprintf.h>
25 #include <android-base/strings.h>
26
27 using android::base::Join;
28 using android::base::StringPrintf;
29
30 namespace android {
31 namespace installd {
32
Exec(const std::vector<std::string> & arg_vector,std::string * error_msg)33 bool Exec(const std::vector<std::string>& arg_vector, std::string* error_msg) {
34 const std::string command_line = Join(arg_vector, ' ');
35
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 execv(program, &args[0]);
58
59 PLOG(ERROR) << "Failed to execv(" << command_line << ")";
60 // _exit to avoid atexit handlers in child.
61 _exit(1);
62 } else {
63 if (pid == -1) {
64 *error_msg = StringPrintf("Failed to execv(%s) because fork failed: %s",
65 command_line.c_str(), strerror(errno));
66 return false;
67 }
68
69 // wait for subprocess to finish
70 int status;
71 pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
72 if (got_pid != pid) {
73 *error_msg = StringPrintf("Failed after fork for execv(%s) because waitpid failed: "
74 "wanted %d, got %d: %s",
75 command_line.c_str(), pid, got_pid, strerror(errno));
76 return false;
77 }
78 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
79 *error_msg = StringPrintf("Failed execv(%s) because non-0 exit status",
80 command_line.c_str());
81 return false;
82 }
83 }
84 return true;
85 }
86
87 } // namespace installd
88 } // namespace android
89