2 * Copyright 2017 Facebook, Inc.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 // This is a helper for the parentDeathSignal test in SubprocessTest.cpp.
19 // Basically, we create two processes, a parent and a child, and set the
20 // child to receive SIGUSR1 when the parent exits. We set the child to
21 // create a file when that happens. The child then kills the parent; the test
22 // will verify that the file actually gets created, which means that everything
23 // worked as intended.
27 #include <sys/types.h>
29 #include <glog/logging.h>
31 #include <folly/Conv.h>
32 #include <folly/Subprocess.h>
33 #include <folly/portability/GFlags.h>
34 #include <folly/portability/Unistd.h>
36 using folly::Subprocess;
38 DEFINE_bool(child, false, "");
41 constexpr int kSignal = SIGUSR1;
44 void runChild(const char* file) {
45 // Block SIGUSR1 so it's queued
47 CHECK_ERR(sigemptyset(&sigs));
48 CHECK_ERR(sigaddset(&sigs, kSignal));
49 CHECK_ERR(sigprocmask(SIG_BLOCK, &sigs, nullptr));
51 // Kill the parent, wait for our signal.
52 CHECK_ERR(kill(getppid(), SIGKILL));
55 CHECK_ERR(sigwait(&sigs, &sig));
56 CHECK_EQ(sig, kSignal);
58 // Signal completion by creating the file
59 CHECK_ERR(creat(file, 0600));
62 [[noreturn]] void runParent(const char* file) {
63 std::vector<std::string> args {"/proc/self/exe", "--child", file};
66 Subprocess::Options().parentDeathSignal(kSignal));
67 CHECK(proc.poll().running());
69 // The child will kill us.
75 int main(int argc, char *argv[]) {
76 gflags::ParseCommandLineFlags(&argc, &argv, true);