119 lines
3.2 KiB
C++
119 lines
3.2 KiB
C++
// Copyright 2014 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "sandbox/linux/services/scoped_process.h"
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#include <fcntl.h>
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#include <signal.h>
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#include <sys/stat.h>
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#include <sys/syscall.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include "base/callback.h"
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#include "base/logging.h"
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#include "base/posix/eintr_wrapper.h"
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#include "build/build_config.h"
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#include "sandbox/linux/services/syscall_wrappers.h"
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#include "sandbox/linux/services/thread_helpers.h"
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namespace sandbox {
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namespace {
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const char kSynchronisationChar[] = "D";
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void WaitForever() {
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while(true) {
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pause();
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}
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}
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} // namespace
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ScopedProcess::ScopedProcess(const base::Closure& child_callback)
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: child_process_id_(-1), process_id_(getpid()) {
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PCHECK(0 == pipe(pipe_fds_));
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#if !defined(THREAD_SANITIZER)
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// Make sure that we can safely fork().
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CHECK(ThreadHelpers::IsSingleThreaded());
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#endif
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child_process_id_ = fork();
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PCHECK(0 <= child_process_id_);
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if (0 == child_process_id_) {
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PCHECK(0 == IGNORE_EINTR(close(pipe_fds_[0])));
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pipe_fds_[0] = -1;
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child_callback.Run();
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// Notify the parent that the closure has run.
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CHECK_EQ(1, HANDLE_EINTR(write(pipe_fds_[1], kSynchronisationChar, 1)));
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WaitForever();
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NOTREACHED();
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_exit(1);
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}
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PCHECK(0 == IGNORE_EINTR(close(pipe_fds_[1])));
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pipe_fds_[1] = -1;
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}
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ScopedProcess::~ScopedProcess() {
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CHECK(IsOriginalProcess());
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if (child_process_id_ >= 0) {
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PCHECK(0 == kill(child_process_id_, SIGKILL));
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siginfo_t process_info;
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PCHECK(0 == HANDLE_EINTR(
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waitid(P_PID, child_process_id_, &process_info, WEXITED)));
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}
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if (pipe_fds_[0] >= 0) {
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PCHECK(0 == IGNORE_EINTR(close(pipe_fds_[0])));
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}
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if (pipe_fds_[1] >= 0) {
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PCHECK(0 == IGNORE_EINTR(close(pipe_fds_[1])));
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}
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}
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int ScopedProcess::WaitForExit(bool* got_signaled) {
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DCHECK(got_signaled);
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CHECK(IsOriginalProcess());
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siginfo_t process_info;
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// WNOWAIT to make sure that the destructor can wait on the child.
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int ret = HANDLE_EINTR(
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waitid(P_PID, child_process_id_, &process_info, WEXITED | WNOWAIT));
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PCHECK(0 == ret) << "Did something else wait on the child?";
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if (process_info.si_code == CLD_EXITED) {
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*got_signaled = false;
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} else if (process_info.si_code == CLD_KILLED ||
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process_info.si_code == CLD_DUMPED) {
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*got_signaled = true;
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} else {
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CHECK(false) << "ScopedProcess needs to be extended for si_code "
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<< process_info.si_code;
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}
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return process_info.si_status;
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}
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bool ScopedProcess::WaitForClosureToRun() {
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char c = 0;
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int ret = HANDLE_EINTR(read(pipe_fds_[0], &c, 1));
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PCHECK(ret >= 0);
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if (0 == ret)
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return false;
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CHECK_EQ(c, kSynchronisationChar[0]);
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return true;
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}
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// It would be problematic if after a fork(), another process would start using
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// this object.
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// This method allows to assert it is not happening.
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bool ScopedProcess::IsOriginalProcess() {
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// Make a direct syscall to bypass glibc caching of PIDs.
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pid_t pid = sys_getpid();
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return pid == process_id_;
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}
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} // namespace sandbox
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