104 lines
3.4 KiB
C++
104 lines
3.4 KiB
C++
/*
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* Copyright (C) 2018 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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#include <atomic>
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#include <memory>
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#include <jni.h>
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#include <signal.h>
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#include <stdint.h>
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#include <sys/mman.h>
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#include "base/globals.h"
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#include "base/mem_map.h"
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#include "fault_handler.h"
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namespace art {
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class TestFaultHandler final : public FaultHandler {
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public:
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explicit TestFaultHandler(FaultManager* manager)
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: FaultHandler(manager),
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map_error_(),
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target_map_(MemMap::MapAnonymous("test-305-mmap",
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/* addr */ nullptr,
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/* byte_count */ kPageSize,
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/* prot */ PROT_NONE,
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/* low_4gb */ false,
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/* reuse */ false,
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/* reservation */ nullptr,
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/* error_msg */ &map_error_,
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/* use_ashmem */ false)),
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was_hit_(false) {
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CHECK(target_map_.IsValid()) << "Unable to create segfault target address " << map_error_;
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manager_->AddHandler(this, /*in_generated_code*/false);
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}
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virtual ~TestFaultHandler() {
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manager_->RemoveHandler(this);
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}
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bool Action(int sig, siginfo_t* siginfo, void* context ATTRIBUTE_UNUSED) override {
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CHECK_EQ(sig, SIGSEGV);
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CHECK_EQ(reinterpret_cast<uint32_t*>(siginfo->si_addr),
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GetTargetPointer()) << "Segfault on unexpected address!";
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CHECK(!was_hit_) << "Recursive signal!";
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was_hit_ = true;
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LOG(INFO) << "SEGV Caught. mprotecting map.";
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CHECK(target_map_.Protect(PROT_READ | PROT_WRITE)) << "Failed to mprotect R/W";
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LOG(INFO) << "Setting value to be read.";
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*GetTargetPointer() = kDataValue;
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LOG(INFO) << "Changing prot to be read-only.";
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CHECK(target_map_.Protect(PROT_READ)) << "Failed to mprotect R-only";
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return true;
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}
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void CauseSegfault() {
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CHECK_EQ(target_map_.GetProtect(), PROT_NONE);
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// This will segfault. The handler should deal with it though and we will get a value out of it.
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uint32_t data = *GetTargetPointer();
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// Prevent re-ordering around the *GetTargetPointer by the compiler
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std::atomic_signal_fence(std::memory_order_seq_cst);
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CHECK(was_hit_);
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CHECK_EQ(data, kDataValue) << "Unexpected read value from mmap";
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CHECK_EQ(target_map_.GetProtect(), PROT_READ);
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LOG(INFO) << "Success!";
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}
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private:
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uint32_t* GetTargetPointer() {
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return reinterpret_cast<uint32_t*>(target_map_.Begin() + 8);
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}
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static constexpr uint32_t kDataValue = 0xDEADBEEF;
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std::string map_error_;
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MemMap target_map_;
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bool was_hit_;
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};
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extern "C" JNIEXPORT void JNICALL Java_Main_runFaultHandlerTest(JNIEnv*, jclass) {
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std::unique_ptr<TestFaultHandler> handler(new TestFaultHandler(&fault_manager));
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handler->CauseSegfault();
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}
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} // namespace art
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