blob: 211d142a2be551fc709abecce7efc744b10b2e42 [file] [log] [blame]
/*
* Copyright (C) 2018 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.
*/
#include <atomic>
#include <memory>
#include <jni.h>
#include <signal.h>
#include <stdint.h>
#include <sys/mman.h>
#include "base/globals.h"
#include "base/mem_map.h"
#include "fault_handler.h"
namespace art {
class TestFaultHandler FINAL : public FaultHandler {
public:
explicit TestFaultHandler(FaultManager* manager)
: FaultHandler(manager),
map_error_(""),
target_map_(MemMap::MapAnonymous("test-305-mmap",
/* addr */ nullptr,
/* byte_count */ kPageSize,
/* prot */ PROT_NONE,
/* low_4gb */ false,
/* reuse */ false,
/* error_msg */ &map_error_,
/* use_ashmem */ false)),
was_hit_(false) {
CHECK(target_map_ != nullptr) << "Unable to create segfault target address " << map_error_;
manager_->AddHandler(this, /*in_generated_code*/false);
}
virtual ~TestFaultHandler() {
manager_->RemoveHandler(this);
}
bool Action(int sig, siginfo_t* siginfo, void* context ATTRIBUTE_UNUSED) OVERRIDE {
CHECK_EQ(sig, SIGSEGV);
CHECK_EQ(reinterpret_cast<uint32_t*>(siginfo->si_addr),
GetTargetPointer()) << "Segfault on unexpected address!";
CHECK(!was_hit_) << "Recursive signal!";
was_hit_ = true;
LOG(INFO) << "SEGV Caught. mprotecting map.";
CHECK(target_map_->Protect(PROT_READ | PROT_WRITE)) << "Failed to mprotect R/W";
LOG(INFO) << "Setting value to be read.";
*GetTargetPointer() = kDataValue;
LOG(INFO) << "Changing prot to be read-only.";
CHECK(target_map_->Protect(PROT_READ)) << "Failed to mprotect R-only";
return true;
}
void CauseSegfault() {
CHECK_EQ(target_map_->GetProtect(), PROT_NONE);
// This will segfault. The handler should deal with it though and we will get a value out of it.
uint32_t data = *GetTargetPointer();
// Prevent re-ordering around the *GetTargetPointer by the compiler
std::atomic_signal_fence(std::memory_order_seq_cst);
CHECK(was_hit_);
CHECK_EQ(data, kDataValue) << "Unexpected read value from mmap";
CHECK_EQ(target_map_->GetProtect(), PROT_READ);
LOG(INFO) << "Success!";
}
private:
uint32_t* GetTargetPointer() {
return reinterpret_cast<uint32_t*>(target_map_->Begin() + 8);
}
static constexpr uint32_t kDataValue = 0xDEADBEEF;
std::string map_error_;
std::unique_ptr<MemMap> target_map_;
bool was_hit_;
};
extern "C" JNIEXPORT void JNICALL Java_Main_runFaultHandlerTest(JNIEnv*, jclass) {
std::unique_ptr<TestFaultHandler> handler(new TestFaultHandler(&fault_manager));
handler->CauseSegfault();
}
} // namespace art