1 /*
2 * Copyright (C) 2010 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 "sigchld_handler.h"
18
19 #include <signal.h>
20 #include <string.h>
21 #include <sys/socket.h>
22 #include <sys/types.h>
23 #include <sys/wait.h>
24 #include <unistd.h>
25
26 #include <android-base/chrono_utils.h>
27 #include <android-base/logging.h>
28 #include <android-base/scopeguard.h>
29 #include <android-base/stringprintf.h>
30
31 #include <thread>
32
33 #include "init.h"
34 #include "service.h"
35 #include "service_list.h"
36
37 using android::base::boot_clock;
38 using android::base::make_scope_guard;
39 using android::base::StringPrintf;
40 using android::base::Timer;
41
42 namespace android {
43 namespace init {
44
ReapOneProcess()45 static pid_t ReapOneProcess() {
46 siginfo_t siginfo = {};
47 // This returns a zombie pid or informs us that there are no zombies left to be reaped.
48 // It does NOT reap the pid; that is done below.
49 if (TEMP_FAILURE_RETRY(waitid(P_ALL, 0, &siginfo, WEXITED | WNOHANG | WNOWAIT)) != 0) {
50 PLOG(ERROR) << "waitid failed";
51 return 0;
52 }
53
54 auto pid = siginfo.si_pid;
55 if (pid == 0) return 0;
56
57 // At this point we know we have a zombie pid, so we use this scopeguard to reap the pid
58 // whenever the function returns from this point forward.
59 // We do NOT want to reap the zombie earlier as in Service::Reap(), we kill(-pid, ...) and we
60 // want the pid to remain valid throughout that (and potentially future) usages.
61 auto reaper = make_scope_guard([pid] { TEMP_FAILURE_RETRY(waitpid(pid, nullptr, WNOHANG)); });
62
63 std::string name;
64 std::string wait_string;
65 Service* service = nullptr;
66
67 if (SubcontextChildReap(pid)) {
68 name = "Subcontext";
69 } else {
70 service = ServiceList::GetInstance().FindService(pid, &Service::pid);
71
72 if (service) {
73 name = StringPrintf("Service '%s' (pid %d)", service->name().c_str(), pid);
74 if (service->flags() & SVC_EXEC) {
75 auto exec_duration = boot_clock::now() - service->time_started();
76 auto exec_duration_ms =
77 std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration).count();
78 wait_string = StringPrintf(" waiting took %f seconds", exec_duration_ms / 1000.0f);
79 } else if (service->flags() & SVC_ONESHOT) {
80 auto exec_duration = boot_clock::now() - service->time_started();
81 auto exec_duration_ms =
82 std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration)
83 .count();
84 wait_string = StringPrintf(" oneshot service took %f seconds in background",
85 exec_duration_ms / 1000.0f);
86 }
87 } else {
88 name = StringPrintf("Untracked pid %d", pid);
89 }
90 }
91
92 if (siginfo.si_code == CLD_EXITED) {
93 LOG(INFO) << name << " exited with status " << siginfo.si_status << wait_string;
94 } else {
95 LOG(INFO) << name << " received signal " << siginfo.si_status << wait_string;
96 }
97
98 if (!service) return pid;
99
100 service->Reap(siginfo);
101
102 if (service->flags() & SVC_TEMPORARY) {
103 ServiceList::GetInstance().RemoveService(*service);
104 }
105
106 return pid;
107 }
108
ReapAnyOutstandingChildren()109 void ReapAnyOutstandingChildren() {
110 while (ReapOneProcess() != 0) {
111 }
112 }
113
WaitToBeReaped(const std::vector<pid_t> & pids,std::chrono::milliseconds timeout)114 void WaitToBeReaped(const std::vector<pid_t>& pids, std::chrono::milliseconds timeout) {
115 Timer t;
116 std::vector<pid_t> alive_pids(pids.begin(), pids.end());
117 while (!alive_pids.empty() && t.duration() < timeout) {
118 pid_t pid;
119 while ((pid = ReapOneProcess()) != 0) {
120 auto it = std::find(alive_pids.begin(), alive_pids.end(), pid);
121 if (it != alive_pids.end()) {
122 alive_pids.erase(it);
123 }
124 }
125 if (alive_pids.empty()) {
126 break;
127 }
128 std::this_thread::sleep_for(50ms);
129 }
130 LOG(INFO) << "Waiting for " << pids.size() << " pids to be reaped took " << t << " with "
131 << alive_pids.size() << " of them still running";
132 }
133
134 } // namespace init
135 } // namespace android
136