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390 lines (365 loc) · 11.3 KB
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// Copyright 2018 Open Source Robotics Foundation, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "signal_handler.hpp"
#include <atomic>
#include <csignal>
#include <mutex>
#include <string>
#include <thread>
// includes for semaphore notification code
#if defined(_WIN32)
#include <windows.h>
#elif defined(__APPLE__)
#include <dispatch/dispatch.h>
#else // posix
#include <semaphore.h>
#endif
#include "rclcpp/logging.hpp"
#include "rclcpp/utilities.hpp"
#include "rcutils/strerror.h"
#include "rmw/impl/cpp/demangle.hpp"
using rclcpp::SignalHandler;
using rclcpp::SignalHandlerOptions;
SignalHandler::signal_handler_type
SignalHandler::set_signal_handler(
int signal_value,
const SignalHandler::signal_handler_type & signal_handler)
{
bool signal_handler_install_failed;
SignalHandler::signal_handler_type old_signal_handler;
#if defined(RCLCPP_HAS_SIGACTION)
ssize_t ret = sigaction(signal_value, &signal_handler, &old_signal_handler);
signal_handler_install_failed = (ret == -1);
#else
old_signal_handler = std::signal(signal_value, signal_handler);
signal_handler_install_failed = (old_signal_handler == SIG_ERR);
#endif
if (signal_handler_install_failed) {
char error_string[1024];
rcutils_strerror(error_string, sizeof(error_string));
auto msg =
"Failed to set signal handler (" + std::to_string(errno) + "): " + error_string;
throw std::runtime_error(msg);
}
return old_signal_handler;
}
// Unfortunately macros (or duplicated code) are needed here,
// as the signal handler must be a function pointer.
#if defined(RCLCPP_HAS_SIGACTION)
void
SignalHandler::signal_handler(
int signum, siginfo_t * siginfo, void * context)
{
RCLCPP_INFO(SignalHandler::get_logger(), "signal_handler(signum=%d)", signum);
auto & instance = SignalHandler::get_global_signal_handler();
auto old_signal_handler = instance.get_old_signal_handler(signum);
if (old_signal_handler.sa_flags & SA_SIGINFO) {
if (old_signal_handler.sa_sigaction != NULL) {
old_signal_handler.sa_sigaction(signum, siginfo, context);
}
} else {
if (
old_signal_handler.sa_handler != NULL && /* Is set */
old_signal_handler.sa_handler != SIG_DFL && /* Is not default*/
old_signal_handler.sa_handler != SIG_IGN) /* Is not ignored */
{
old_signal_handler.sa_handler(signum);
}
}
instance.signal_handler_common();
}
#else
void
SignalHandler::signal_handler(int signum)
{
RCLCPP_INFO(SignalHandler::get_logger(), "signal_handler(signum=%d)", signum);
auto & instance = SignalHandler::get_global_signal_handler();
auto old_signal_handler = instance.get_old_signal_handler(signum);
if (
SIG_ERR != old_signal_handler && SIG_IGN != old_signal_handler &&
SIG_DFL != old_signal_handler)
{
old_signal_handler(signum);
}
instance.signal_handler_common();
}
#endif
rclcpp::Logger &
SignalHandler::get_logger()
{
return SignalHandler::get_global_signal_handler().logger_;
}
SignalHandler &
SignalHandler::get_global_signal_handler()
{
static SignalHandler & signal_handler = *new SignalHandler();
return signal_handler;
}
bool
SignalHandler::install(SignalHandlerOptions signal_handler_options)
{
std::lock_guard<std::mutex> lock(install_mutex_);
bool already_installed = installed_.exchange(true);
if (already_installed) {
return false;
}
if (signal_handler_options == SignalHandlerOptions::None) {
return true;
}
signal_handlers_options_ = signal_handler_options;
try {
setup_wait_for_signal();
signal_received_.store(false);
SignalHandler::signal_handler_type handler_argument;
#if defined(RCLCPP_HAS_SIGACTION)
memset(&handler_argument, 0, sizeof(handler_argument));
sigemptyset(&handler_argument.sa_mask);
handler_argument.sa_sigaction = &this->signal_handler;
handler_argument.sa_flags = SA_SIGINFO;
#else
handler_argument = &this->signal_handler;
#endif
if (
signal_handler_options == SignalHandlerOptions::SigInt ||
signal_handler_options == SignalHandlerOptions::All)
{
old_sigint_handler_ = set_signal_handler(SIGINT, handler_argument);
}
if (
signal_handler_options == SignalHandlerOptions::SigTerm ||
signal_handler_options == SignalHandlerOptions::All)
{
old_sigterm_handler_ = set_signal_handler(SIGTERM, handler_argument);
}
signal_handler_thread_ = std::thread(&SignalHandler::deferred_signal_handler, this);
} catch (...) {
installed_.store(false);
throw;
}
RCLCPP_DEBUG(get_logger(), "signal handler installed");
return true;
}
bool
SignalHandler::uninstall()
{
std::lock_guard<std::mutex> lock(install_mutex_);
bool installed = installed_.exchange(false);
if (!installed) {
return false;
}
try {
// TODO(wjwwood): what happens if someone overrides our signal handler then calls uninstall?
// I think we need to assert that we're the current signal handler, and mitigate if not.
if (
SignalHandlerOptions::SigInt == signal_handlers_options_ ||
SignalHandlerOptions::All == signal_handlers_options_)
{
set_signal_handler(SIGINT, old_sigint_handler_);
}
if (
SignalHandlerOptions::SigTerm == signal_handlers_options_ ||
SignalHandlerOptions::All == signal_handlers_options_)
{
set_signal_handler(SIGTERM, old_sigterm_handler_);
}
signal_handlers_options_ = SignalHandlerOptions::None;
RCLCPP_DEBUG(get_logger(), "SignalHandler::uninstall(): notifying deferred signal handler");
notify_signal_handler();
if (signal_handler_thread_.joinable()) {
signal_handler_thread_.join();
}
teardown_wait_for_signal();
} catch (...) {
installed_.exchange(true);
throw;
}
RCLCPP_DEBUG(get_logger(), "signal handler uninstalled");
return true;
}
bool
SignalHandler::is_installed()
{
return installed_.load();
}
SignalHandler::~SignalHandler()
{
try {
uninstall();
} catch (const std::exception & exc) {
RCLCPP_ERROR(
get_logger(),
"caught %s exception when uninstalling signal handlers in rclcpp::~SignalHandler: %s",
rmw::impl::cpp::demangle(exc).c_str(), exc.what());
} catch (...) {
RCLCPP_ERROR(
get_logger(),
"caught unknown exception when uninstalling signal handlers in rclcpp::~SignalHandler");
}
}
SignalHandler::signal_handler_type
SignalHandler::get_old_signal_handler(int signum)
{
if (SIGINT == signum) {
return old_sigint_handler_;
} else if (SIGTERM == signum) {
return old_sigterm_handler_;
}
#if defined(RCLCPP_HAS_SIGACTION)
SignalHandler::signal_handler_type ret;
memset(&ret, 0, sizeof(ret));
sigemptyset(&ret.sa_mask);
ret.sa_handler = SIG_DFL;
return ret;
#else
return SIG_DFL;
#endif
}
void
SignalHandler::signal_handler_common()
{
auto & instance = SignalHandler::get_global_signal_handler();
instance.signal_received_.store(true);
RCLCPP_DEBUG(
get_logger(),
"signal_handler(): notifying deferred signal handler");
instance.notify_signal_handler();
}
void
SignalHandler::deferred_signal_handler()
{
while (true) {
if (signal_received_.exchange(false)) {
RCLCPP_DEBUG(get_logger(), "deferred_signal_handler(): shutting down");
for (auto context_ptr : rclcpp::get_contexts()) {
if (context_ptr->get_init_options().shutdown_on_signal) {
RCLCPP_DEBUG(
get_logger(),
"deferred_signal_handler(): "
"shutting down rclcpp::Context @ %p, because it had shutdown_on_signal == true",
static_cast<void *>(context_ptr.get()));
context_ptr->shutdown("signal handler");
}
}
}
if (!is_installed()) {
RCLCPP_DEBUG(get_logger(), "deferred_signal_handler(): signal handling uninstalled");
break;
}
RCLCPP_DEBUG(
get_logger(), "deferred_signal_handler(): waiting for SIGINT/SIGTERM or uninstall");
wait_for_signal();
RCLCPP_DEBUG(
get_logger(), "deferred_signal_handler(): woken up due to SIGINT/SIGTERM or uninstall");
}
}
void
SignalHandler::setup_wait_for_signal()
{
#if defined(_WIN32)
signal_handler_sem_ = CreateSemaphore(
NULL, // default security attributes
0, // initial semaphore count
1, // maximum semaphore count
NULL); // unnamed semaphore
if (NULL == signal_handler_sem_) {
throw std::runtime_error("CreateSemaphore() failed in setup_wait_for_signal()");
}
#elif defined(__APPLE__)
signal_handler_sem_ = dispatch_semaphore_create(0);
#else // posix
if (-1 == sem_init(&signal_handler_sem_, 0, 0)) {
throw std::runtime_error(std::string("sem_init() failed: ") + strerror(errno));
}
#endif
wait_for_signal_is_setup_.store(true);
}
void
SignalHandler::teardown_wait_for_signal() noexcept
{
if (!wait_for_signal_is_setup_.exchange(false)) {
return;
}
#if defined(_WIN32)
CloseHandle(signal_handler_sem_);
#elif defined(__APPLE__)
dispatch_release(signal_handler_sem_);
#else // posix
if (-1 == sem_destroy(&signal_handler_sem_)) {
RCLCPP_ERROR(get_logger(), "invalid semaphore in teardown_wait_for_signal()");
}
#endif
}
void
SignalHandler::wait_for_signal()
{
if (!wait_for_signal_is_setup_.load()) {
RCLCPP_ERROR(get_logger(), "called wait_for_signal() before setup_wait_for_signal()");
return;
}
#if defined(_WIN32)
DWORD dw_wait_result = WaitForSingleObject(signal_handler_sem_, INFINITE);
switch (dw_wait_result) {
case WAIT_ABANDONED:
RCLCPP_ERROR(
get_logger(), "WaitForSingleObject() failed in wait_for_signal() with WAIT_ABANDONED: %s",
GetLastError());
break;
case WAIT_OBJECT_0:
// successful
break;
case WAIT_TIMEOUT:
RCLCPP_ERROR(get_logger(), "WaitForSingleObject() timedout out in wait_for_signal()");
break;
case WAIT_FAILED:
RCLCPP_ERROR(
get_logger(), "WaitForSingleObject() failed in wait_for_signal(): %s", GetLastError());
break;
default:
RCLCPP_ERROR(
get_logger(), "WaitForSingleObject() gave unknown return in wait_for_signal(): %s",
GetLastError());
}
#elif defined(__APPLE__)
dispatch_semaphore_wait(signal_handler_sem_, DISPATCH_TIME_FOREVER);
#else // posix
int s;
do {
s = sem_wait(&signal_handler_sem_);
} while (-1 == s && EINTR == errno);
#endif
}
void
SignalHandler::notify_signal_handler() noexcept
{
if (!wait_for_signal_is_setup_.load()) {
return;
}
#if defined(_WIN32)
if (!ReleaseSemaphore(signal_handler_sem_, 1, NULL)) {
RCLCPP_ERROR(
get_logger(), "ReleaseSemaphore() failed in notify_signal_handler(): %s", GetLastError());
}
#elif defined(__APPLE__)
dispatch_semaphore_signal(signal_handler_sem_);
#else // posix
if (-1 == sem_post(&signal_handler_sem_)) {
RCLCPP_ERROR(get_logger(), "sem_post failed in notify_signal_handler()");
}
#endif
}
rclcpp::SignalHandlerOptions
SignalHandler::get_current_signal_handler_options()
{
return signal_handlers_options_;
}
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