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/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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.
*/
#ifndef LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
#define LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
#include <errno.h>
#include <signal.h>
#include <functional>
#include "android-base/macros.h"
#include "Allocator.h"
#include "log.h"
namespace android {
class ScopedSignalHandler {
public:
using Fn = std::function<void(ScopedSignalHandler&, int, siginfo_t*, void*)>;
explicit ScopedSignalHandler(Allocator<ScopedSignalHandler> allocator) : signal_(-1) {
if (handler_map_ == nullptr) {
Allocator<SignalFnMap> map_allocator = allocator;
handler_map_ = map_allocator.make_unique(allocator);
}
}
~ScopedSignalHandler() { reset(); }
template <class F>
void install(int signal, F&& f) {
if (signal_ != -1) MEM_LOG_ALWAYS_FATAL("ScopedSignalHandler already installed");
if (handler_map_->find(signal) != handler_map_->end()) {
MEM_LOG_ALWAYS_FATAL("ScopedSignalHandler already installed for %d", signal);
}
(*handler_map_)[signal] =
SignalFn([=](int signal, siginfo_t* si, void* uctx) { f(*this, signal, si, uctx); });
struct sigaction act {};
act.sa_sigaction = [](int signal, siginfo_t* si, void* uctx) {
((*handler_map_)[signal])(signal, si, uctx);
};
act.sa_flags = SA_SIGINFO;
int ret = sigaction(signal, &act, &old_act_);
if (ret < 0) {
MEM_LOG_ALWAYS_FATAL("failed to install segfault handler: %s", strerror(errno));
}
signal_ = signal;
}
void reset() {
if (signal_ != -1) {
int ret = sigaction(signal_, &old_act_, NULL);
if (ret < 0) {
MEM_ALOGE("failed to uninstall segfault handler");
}
handler_map_->erase(signal_);
if (handler_map_->empty()) {
handler_map_.reset();
}
signal_ = -1;
}
}
private:
using SignalFn = std::function<void(int, siginfo_t*, void*)>;
using SignalFnMap = allocator::unordered_map<int, SignalFn>;
DISALLOW_COPY_AND_ASSIGN(ScopedSignalHandler);
int signal_;
struct sigaction old_act_;
static Allocator<SignalFnMap>::unique_ptr handler_map_;
};
} // namespace android
#endif // LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
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