0965c0247b
Vendor blobs on ryu mprotect heap pages, causing segfaults when dumping
unreachable memory. Handle segfaults within HeapWalker by mapping a
zero page over any unreadable pages. HeapWalker runs in the forked
process, so the mapping will not affect the original process.
Bug: 28269332
Change-Id: I16245af722123f2ad467cbc6f245a70666c55544
(cherry picked from commit ba5d9ff6d9)
84 lines
2.4 KiB
C++
84 lines
2.4 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 "log.h"
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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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ScopedSignalHandler(Allocator<Fn> allocator) : allocator_(allocator), signal_(-1) {}
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~ScopedSignalHandler() {
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reset();
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}
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template <class F>
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void install(int signal, F&& f) {
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LOG_ALWAYS_FATAL_IF(signal_ != -1, "ScopedSignalHandler already installed");
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handler_ = SignalFn(std::allocator_arg, allocator_,
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[=](int signal, siginfo_t* si, void* uctx) {
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f(*this, signal, si, uctx);
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});
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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_(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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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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ALOGE("failed to uninstall segfault handler");
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}
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handler_ = SignalFn{};
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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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DISALLOW_COPY_AND_ASSIGN(ScopedSignalHandler);
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Allocator<Fn> allocator_;
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int signal_;
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struct sigaction old_act_;
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// TODO(ccross): to support multiple ScopedSignalHandlers handler_ would need
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// to be a static map of signals to handlers, but allocated with Allocator.
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static SignalFn handler_;
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};
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#endif // LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_
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