87315e9d2f
SIGBUS shouldn't happen, since all of the regions being walked were previously read out of /prod/pid/maps, but it seems to happen rarely. Catch it so it can produce a better log message. Bug: 128983715 Test: atest memunreachable_test Change-Id: I82d3941a382a0451c0dda12f5eb849ad8d697bc9
95 lines
2.7 KiB
C++
95 lines
2.7 KiB
C++
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
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#define LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
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#include <errno.h>
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#include <signal.h>
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#include <functional>
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#include "android-base/macros.h"
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#include "Allocator.h"
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#include "log.h"
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namespace android {
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class ScopedSignalHandler {
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public:
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using Fn = std::function<void(ScopedSignalHandler&, int, siginfo_t*, void*)>;
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explicit ScopedSignalHandler(Allocator<ScopedSignalHandler> allocator) : signal_(-1) {
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if (handler_map_ == nullptr) {
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Allocator<SignalFnMap> map_allocator = allocator;
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handler_map_ = map_allocator.make_unique(allocator);
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}
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}
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~ScopedSignalHandler() { reset(); }
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template <class F>
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void install(int signal, F&& f) {
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if (signal_ != -1) MEM_LOG_ALWAYS_FATAL("ScopedSignalHandler already installed");
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if (handler_map_->find(signal) != handler_map_->end()) {
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MEM_LOG_ALWAYS_FATAL("ScopedSignalHandler already installed for %d", signal);
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}
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(*handler_map_)[signal] =
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SignalFn([=](int signal, siginfo_t* si, void* uctx) { f(*this, signal, si, uctx); });
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struct sigaction act {};
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act.sa_sigaction = [](int signal, siginfo_t* si, void* uctx) {
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((*handler_map_)[signal])(signal, si, uctx);
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};
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act.sa_flags = SA_SIGINFO;
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int ret = sigaction(signal, &act, &old_act_);
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if (ret < 0) {
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MEM_LOG_ALWAYS_FATAL("failed to install segfault handler: %s", strerror(errno));
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}
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signal_ = signal;
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}
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void reset() {
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if (signal_ != -1) {
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int ret = sigaction(signal_, &old_act_, NULL);
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if (ret < 0) {
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MEM_ALOGE("failed to uninstall segfault handler");
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}
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handler_map_->erase(signal_);
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if (handler_map_->empty()) {
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handler_map_.reset();
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}
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signal_ = -1;
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}
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}
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private:
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using SignalFn = std::function<void(int, siginfo_t*, void*)>;
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using SignalFnMap = allocator::unordered_map<int, SignalFn>;
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DISALLOW_COPY_AND_ASSIGN(ScopedSignalHandler);
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int signal_;
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struct sigaction old_act_;
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static Allocator<SignalFnMap>::unique_ptr handler_map_;
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};
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} // namespace android
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#endif // LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
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