libunwindstack/tests/MapInfoGetElfTest.cpp - android_system_core - Gitiles

 /*
  * 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.
  */

 #include <elf.h>
 #include <errno.h>
 #include <signal.h>
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/ptrace.h>
 #include <sys/types.h>
 #include <unistd.h>

 #include <atomic>
 #include <memory>
 #include <thread>
 #include <vector>

 #include <android-base/file.h>
 #include <gtest/gtest.h>

 #include <unwindstack/Elf.h>
 #include <unwindstack/MapInfo.h>
 #include <unwindstack/Maps.h>
 #include <unwindstack/Memory.h>

 #include "ElfTestUtils.h"
 #include "MemoryFake.h"

 namespace unwindstack {

 class MapInfoGetElfTest : public ::testing::Test {
  protected:
   void SetUp() override {
     memory_ = new MemoryFake;
     process_memory_.reset(memory_);
   }

   template <typename Ehdr, typename Shdr>
   static void InitElf(uint64_t sh_offset, Ehdr* ehdr, uint8_t class_type, uint8_t machine_type) {
     memset(ehdr, 0, sizeof(*ehdr));
     memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
     ehdr->e_ident[EI_CLASS] = class_type;
     ehdr->e_machine = machine_type;
     ehdr->e_shoff = sh_offset;
     ehdr->e_shentsize = sizeof(Shdr) + 100;
     ehdr->e_shnum = 4;
   }

   const size_t kMapSize = 4096;

   std::shared_ptr<Memory> process_memory_;
   MemoryFake* memory_;

   TemporaryFile elf_;
 };

 TEST_F(MapInfoGetElfTest, invalid) {
   MapInfo info(nullptr, 0x1000, 0x2000, 0, PROT_READ, "");

   // The map is empty, but this should still create an invalid elf object.
   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_FALSE(elf->valid());
 }

 TEST_F(MapInfoGetElfTest, valid32) {
   MapInfo info(nullptr, 0x3000, 0x4000, 0, PROT_READ, "");

   Elf32_Ehdr ehdr;
   TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
   memory_->SetMemory(0x3000, &ehdr, sizeof(ehdr));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
   EXPECT_EQ(ELFCLASS32, elf->class_type());
 }

 TEST_F(MapInfoGetElfTest, valid64) {
   MapInfo info(nullptr, 0x8000, 0x9000, 0, PROT_READ, "");

   Elf64_Ehdr ehdr;
   TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
   memory_->SetMemory(0x8000, &ehdr, sizeof(ehdr));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
   EXPECT_EQ(ELFCLASS64, elf->class_type());
 }

 TEST_F(MapInfoGetElfTest, invalid_arch_mismatch) {
   MapInfo info(nullptr, 0x3000, 0x4000, 0, PROT_READ, "");

   Elf32_Ehdr ehdr;
   TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
   memory_->SetMemory(0x3000, &ehdr, sizeof(ehdr));

   Elf* elf = info.GetElf(process_memory_, ARCH_X86);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_FALSE(elf->valid());
 }

 TEST_F(MapInfoGetElfTest, gnu_debugdata_init32) {
   MapInfo info(nullptr, 0x2000, 0x3000, 0, PROT_READ, "");

   TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, true,
                                                [&](uint64_t offset, const void* ptr, size_t size) {
                                                  memory_->SetMemory(0x2000 + offset, ptr, size);
                                                });

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
   EXPECT_EQ(ELFCLASS32, elf->class_type());
   EXPECT_TRUE(elf->gnu_debugdata_interface() != nullptr);
 }

 TEST_F(MapInfoGetElfTest, gnu_debugdata_init64) {
   MapInfo info(nullptr, 0x5000, 0x8000, 0, PROT_READ, "");

   TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, true,
                                                [&](uint64_t offset, const void* ptr, size_t size) {
                                                  memory_->SetMemory(0x5000 + offset, ptr, size);
                                                });

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
   EXPECT_EQ(ELFCLASS64, elf->class_type());
   EXPECT_TRUE(elf->gnu_debugdata_interface() != nullptr);
 }

 TEST_F(MapInfoGetElfTest, end_le_start) {
   MapInfo info(nullptr, 0x1000, 0x1000, 0, PROT_READ, elf_.path);

   Elf32_Ehdr ehdr;
   TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
   ASSERT_TRUE(android::base::WriteFully(elf_.fd, &ehdr, sizeof(ehdr)));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_FALSE(elf->valid());

   info.elf.reset();
   info.end = 0xfff;
   elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_FALSE(elf->valid());

   // Make sure this test is valid.
   info.elf.reset();
   info.end = 0x2000;
   elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
 }

 // Verify that if the offset is non-zero but there is no elf at the offset,
 // that the full file is used.
 TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_full_file) {
   MapInfo info(nullptr, 0x1000, 0x2000, 0x100, PROT_READ, elf_.path);

   std::vector<uint8_t> buffer(0x1000);
   memset(buffer.data(), 0, buffer.size());
   Elf32_Ehdr ehdr;
   TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
   memcpy(buffer.data(), &ehdr, sizeof(ehdr));
   ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   ASSERT_TRUE(elf->memory() != nullptr);
   ASSERT_EQ(0x100U, info.elf_offset);

   // Read the entire file.
   memset(buffer.data(), 0, buffer.size());
   ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), buffer.size()));
   ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
   for (size_t i = sizeof(ehdr); i < buffer.size(); i++) {
     ASSERT_EQ(0, buffer[i]) << "Failed at byte " << i;
   }

   ASSERT_FALSE(elf->memory()->ReadFully(buffer.size(), buffer.data(), 1));
 }

 // Verify that if the offset is non-zero and there is an elf at that
 // offset, that only part of the file is used.
 TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file) {
   MapInfo info(nullptr, 0x1000, 0x2000, 0x2000, PROT_READ, elf_.path);

   std::vector<uint8_t> buffer(0x4000);
   memset(buffer.data(), 0, buffer.size());
   Elf32_Ehdr ehdr;
   TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
   memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
   ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   ASSERT_TRUE(elf->memory() != nullptr);
   ASSERT_EQ(0U, info.elf_offset);

   // Read the valid part of the file.
   ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), 0x1000));
   ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
   for (size_t i = sizeof(ehdr); i < 0x1000; i++) {
     ASSERT_EQ(0, buffer[i]) << "Failed at byte " << i;
   }

   ASSERT_FALSE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
 }

 // Verify that if the offset is non-zero and there is an elf at that
 // offset, that only part of the file is used. Further verify that if the
 // embedded elf is bigger than the initial map, the new object is larger
 // than the original map size. Do this for a 32 bit elf and a 64 bit elf.
 TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf32) {
   MapInfo info(nullptr, 0x5000, 0x6000, 0x1000, PROT_READ, elf_.path);

   std::vector<uint8_t> buffer(0x4000);
   memset(buffer.data(), 0, buffer.size());
   Elf32_Ehdr ehdr;
   TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
   ehdr.e_shoff = 0x2000;
   ehdr.e_shentsize = sizeof(Elf32_Shdr) + 100;
   ehdr.e_shnum = 4;
   memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
   ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   ASSERT_TRUE(elf->memory() != nullptr);
   ASSERT_EQ(0U, info.elf_offset);

   // Verify the memory is a valid elf.
   memset(buffer.data(), 0, buffer.size());
   ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), 0x1000));
   ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));

   // Read past the end of what would normally be the size of the map.
   ASSERT_TRUE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
 }

 TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf64) {
   MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ, elf_.path);

   std::vector<uint8_t> buffer(0x4000);
   memset(buffer.data(), 0, buffer.size());
   Elf64_Ehdr ehdr;
   TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
   ehdr.e_shoff = 0x2000;
   ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
   ehdr.e_shnum = 4;
   memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
   ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

   Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_TRUE(elf->valid());
   ASSERT_TRUE(elf->memory() != nullptr);
   ASSERT_EQ(0U, info.elf_offset);

   // Verify the memory is a valid elf.
   memset(buffer.data(), 0, buffer.size());
   ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), 0x1000));
   ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));

   // Read past the end of what would normally be the size of the map.
   ASSERT_TRUE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
 }

 TEST_F(MapInfoGetElfTest, check_device_maps) {
   MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ | MAPS_FLAGS_DEVICE_MAP,
                "/dev/something");

   // Create valid elf data in process memory for this to verify that only
   // the name is causing invalid elf data.
   Elf64_Ehdr ehdr;
   TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_X86_64);
   ehdr.e_shoff = 0x2000;
   ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
   ehdr.e_shnum = 0;
   memory_->SetMemory(0x7000, &ehdr, sizeof(ehdr));

   Elf* elf = info.GetElf(process_memory_, ARCH_X86_64);
   ASSERT_TRUE(elf != nullptr);
   ASSERT_FALSE(elf->valid());

   // Set the name to nothing to verify that it still fails.
   info.elf.reset();
   info.name = "";
   elf = info.GetElf(process_memory_, ARCH_X86_64);
   ASSERT_FALSE(elf->valid());

   // Change the flags and verify the elf is valid now.
   info.elf.reset();
   info.flags = PROT_READ;
   elf = info.GetElf(process_memory_, ARCH_X86_64);
   ASSERT_TRUE(elf->valid());
 }

 TEST_F(MapInfoGetElfTest, multiple_thread_get_elf) {
   static constexpr size_t kNumConcurrentThreads = 100;

   Elf64_Ehdr ehdr;
   TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_X86_64);
   ehdr.e_shoff = 0x2000;
   ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
   ehdr.e_shnum = 0;
   memory_->SetMemory(0x7000, &ehdr, sizeof(ehdr));

   Elf* elf_in_threads[kNumConcurrentThreads];
   std::vector<std::thread*> threads;

   std::atomic_bool wait;
   wait = true;
   // Create all of the threads and have them do the GetElf at the same time
   // to make it likely that a race will occur.
   MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ, "");
   for (size_t i = 0; i < kNumConcurrentThreads; i++) {
     std::thread* thread = new std::thread([i, this, &wait, &info, &elf_in_threads]() {
       while (wait)
         ;
       Elf* elf = info.GetElf(process_memory_, ARCH_X86_64);
       elf_in_threads[i] = elf;
     });
     threads.push_back(thread);
   }
   ASSERT_TRUE(info.elf == nullptr);

   // Set them all going and wait for the threads to finish.
   wait = false;
   for (auto thread : threads) {
     thread->join();
     delete thread;
   }

   // Now verify that all of the elf files are exactly the same and valid.
   Elf* elf = info.elf.get();
   ASSERT_TRUE(elf != nullptr);
   EXPECT_TRUE(elf->valid());
   for (size_t i = 0; i < kNumConcurrentThreads; i++) {
     EXPECT_EQ(elf, elf_in_threads[i]) << "Thread " << i << " mismatched.";
   }
 }

 }  // namespace unwindstack
	/*
	* 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.
	*/

	#include <elf.h>
	#include <errno.h>
	#include <signal.h>
	#include <string.h>
	#include <sys/mman.h>
	#include <sys/ptrace.h>
	#include <sys/types.h>
	#include <unistd.h>

	#include <atomic>
	#include <memory>
	#include <thread>
	#include <vector>

	#include <android-base/file.h>
	#include <gtest/gtest.h>

	#include <unwindstack/Elf.h>
	#include <unwindstack/MapInfo.h>
	#include <unwindstack/Maps.h>
	#include <unwindstack/Memory.h>

	#include "ElfTestUtils.h"
	#include "MemoryFake.h"

	namespace unwindstack {

	class MapInfoGetElfTest : public ::testing::Test {
	protected:
	void SetUp() override {
	memory_ = new MemoryFake;
	process_memory_.reset(memory_);
	}

	template <typename Ehdr, typename Shdr>
	static void InitElf(uint64_t sh_offset, Ehdr* ehdr, uint8_t class_type, uint8_t machine_type) {
	memset(ehdr, 0, sizeof(*ehdr));
	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
	ehdr->e_ident[EI_CLASS] = class_type;
	ehdr->e_machine = machine_type;
	ehdr->e_shoff = sh_offset;
	ehdr->e_shentsize = sizeof(Shdr) + 100;
	ehdr->e_shnum = 4;
	}

	const size_t kMapSize = 4096;

	std::shared_ptr<Memory> process_memory_;
	MemoryFake* memory_;

	TemporaryFile elf_;
	};

	TEST_F(MapInfoGetElfTest, invalid) {
	MapInfo info(nullptr, 0x1000, 0x2000, 0, PROT_READ, "");

	// The map is empty, but this should still create an invalid elf object.
	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_FALSE(elf->valid());
	}

	TEST_F(MapInfoGetElfTest, valid32) {
	MapInfo info(nullptr, 0x3000, 0x4000, 0, PROT_READ, "");

	Elf32_Ehdr ehdr;
	TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
	memory_->SetMemory(0x3000, &ehdr, sizeof(ehdr));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
	EXPECT_EQ(ELFCLASS32, elf->class_type());
	}

	TEST_F(MapInfoGetElfTest, valid64) {
	MapInfo info(nullptr, 0x8000, 0x9000, 0, PROT_READ, "");

	Elf64_Ehdr ehdr;
	TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
	memory_->SetMemory(0x8000, &ehdr, sizeof(ehdr));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
	EXPECT_EQ(ELFCLASS64, elf->class_type());
	}

	TEST_F(MapInfoGetElfTest, invalid_arch_mismatch) {
	MapInfo info(nullptr, 0x3000, 0x4000, 0, PROT_READ, "");

	Elf32_Ehdr ehdr;
	TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
	memory_->SetMemory(0x3000, &ehdr, sizeof(ehdr));

	Elf* elf = info.GetElf(process_memory_, ARCH_X86);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_FALSE(elf->valid());
	}

	TEST_F(MapInfoGetElfTest, gnu_debugdata_init32) {
	MapInfo info(nullptr, 0x2000, 0x3000, 0, PROT_READ, "");

	TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, true,
	[&](uint64_t offset, const void* ptr, size_t size) {
	memory_->SetMemory(0x2000 + offset, ptr, size);
	});

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
	EXPECT_EQ(ELFCLASS32, elf->class_type());
	EXPECT_TRUE(elf->gnu_debugdata_interface() != nullptr);
	}

	TEST_F(MapInfoGetElfTest, gnu_debugdata_init64) {
	MapInfo info(nullptr, 0x5000, 0x8000, 0, PROT_READ, "");

	TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, true,
	[&](uint64_t offset, const void* ptr, size_t size) {
	memory_->SetMemory(0x5000 + offset, ptr, size);
	});

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
	EXPECT_EQ(ELFCLASS64, elf->class_type());
	EXPECT_TRUE(elf->gnu_debugdata_interface() != nullptr);
	}

	TEST_F(MapInfoGetElfTest, end_le_start) {
	MapInfo info(nullptr, 0x1000, 0x1000, 0, PROT_READ, elf_.path);

	Elf32_Ehdr ehdr;
	TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
	ASSERT_TRUE(android::base::WriteFully(elf_.fd, &ehdr, sizeof(ehdr)));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_FALSE(elf->valid());

	info.elf.reset();
	info.end = 0xfff;
	elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_FALSE(elf->valid());

	// Make sure this test is valid.
	info.elf.reset();
	info.end = 0x2000;
	elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	}

	// Verify that if the offset is non-zero but there is no elf at the offset,
	// that the full file is used.
	TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_full_file) {
	MapInfo info(nullptr, 0x1000, 0x2000, 0x100, PROT_READ, elf_.path);

	std::vector<uint8_t> buffer(0x1000);
	memset(buffer.data(), 0, buffer.size());
	Elf32_Ehdr ehdr;
	TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
	memcpy(buffer.data(), &ehdr, sizeof(ehdr));
	ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	ASSERT_TRUE(elf->memory() != nullptr);
	ASSERT_EQ(0x100U, info.elf_offset);

	// Read the entire file.
	memset(buffer.data(), 0, buffer.size());
	ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), buffer.size()));
	ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
	for (size_t i = sizeof(ehdr); i < buffer.size(); i++) {
	ASSERT_EQ(0, buffer[i]) << "Failed at byte " << i;
	}

	ASSERT_FALSE(elf->memory()->ReadFully(buffer.size(), buffer.data(), 1));
	}

	// Verify that if the offset is non-zero and there is an elf at that
	// offset, that only part of the file is used.
	TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file) {
	MapInfo info(nullptr, 0x1000, 0x2000, 0x2000, PROT_READ, elf_.path);

	std::vector<uint8_t> buffer(0x4000);
	memset(buffer.data(), 0, buffer.size());
	Elf32_Ehdr ehdr;
	TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
	memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
	ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	ASSERT_TRUE(elf->memory() != nullptr);
	ASSERT_EQ(0U, info.elf_offset);

	// Read the valid part of the file.
	ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), 0x1000));
	ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
	for (size_t i = sizeof(ehdr); i < 0x1000; i++) {
	ASSERT_EQ(0, buffer[i]) << "Failed at byte " << i;
	}

	ASSERT_FALSE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
	}

	// Verify that if the offset is non-zero and there is an elf at that
	// offset, that only part of the file is used. Further verify that if the
	// embedded elf is bigger than the initial map, the new object is larger
	// than the original map size. Do this for a 32 bit elf and a 64 bit elf.
	TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf32) {
	MapInfo info(nullptr, 0x5000, 0x6000, 0x1000, PROT_READ, elf_.path);

	std::vector<uint8_t> buffer(0x4000);
	memset(buffer.data(), 0, buffer.size());
	Elf32_Ehdr ehdr;
	TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
	ehdr.e_shoff = 0x2000;
	ehdr.e_shentsize = sizeof(Elf32_Shdr) + 100;
	ehdr.e_shnum = 4;
	memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
	ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	ASSERT_TRUE(elf->memory() != nullptr);
	ASSERT_EQ(0U, info.elf_offset);

	// Verify the memory is a valid elf.
	memset(buffer.data(), 0, buffer.size());
	ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), 0x1000));
	ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));

	// Read past the end of what would normally be the size of the map.
	ASSERT_TRUE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
	}

	TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf64) {
	MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ, elf_.path);

	std::vector<uint8_t> buffer(0x4000);
	memset(buffer.data(), 0, buffer.size());
	Elf64_Ehdr ehdr;
	TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
	ehdr.e_shoff = 0x2000;
	ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
	ehdr.e_shnum = 4;
	memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
	ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));

	Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_TRUE(elf->valid());
	ASSERT_TRUE(elf->memory() != nullptr);
	ASSERT_EQ(0U, info.elf_offset);

	// Verify the memory is a valid elf.
	memset(buffer.data(), 0, buffer.size());
	ASSERT_TRUE(elf->memory()->ReadFully(0, buffer.data(), 0x1000));
	ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));

	// Read past the end of what would normally be the size of the map.
	ASSERT_TRUE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
	}

	TEST_F(MapInfoGetElfTest, check_device_maps) {
	MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ \| MAPS_FLAGS_DEVICE_MAP,
	"/dev/something");

	// Create valid elf data in process memory for this to verify that only
	// the name is causing invalid elf data.
	Elf64_Ehdr ehdr;
	TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_X86_64);
	ehdr.e_shoff = 0x2000;
	ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
	ehdr.e_shnum = 0;
	memory_->SetMemory(0x7000, &ehdr, sizeof(ehdr));

	Elf* elf = info.GetElf(process_memory_, ARCH_X86_64);
	ASSERT_TRUE(elf != nullptr);
	ASSERT_FALSE(elf->valid());

	// Set the name to nothing to verify that it still fails.
	info.elf.reset();
	info.name = "";
	elf = info.GetElf(process_memory_, ARCH_X86_64);
	ASSERT_FALSE(elf->valid());

	// Change the flags and verify the elf is valid now.
	info.elf.reset();
	info.flags = PROT_READ;
	elf = info.GetElf(process_memory_, ARCH_X86_64);
	ASSERT_TRUE(elf->valid());
	}

	TEST_F(MapInfoGetElfTest, multiple_thread_get_elf) {
	static constexpr size_t kNumConcurrentThreads = 100;

	Elf64_Ehdr ehdr;
	TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_X86_64);
	ehdr.e_shoff = 0x2000;
	ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
	ehdr.e_shnum = 0;
	memory_->SetMemory(0x7000, &ehdr, sizeof(ehdr));

	Elf* elf_in_threads[kNumConcurrentThreads];
	std::vector<std::thread*> threads;

	std::atomic_bool wait;
	wait = true;
	// Create all of the threads and have them do the GetElf at the same time
	// to make it likely that a race will occur.
	MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ, "");
	for (size_t i = 0; i < kNumConcurrentThreads; i++) {
	std::thread* thread = new std::thread([i, this, &wait, &info, &elf_in_threads]() {
	while (wait)
	;
	Elf* elf = info.GetElf(process_memory_, ARCH_X86_64);
	elf_in_threads[i] = elf;
	});
	threads.push_back(thread);
	}
	ASSERT_TRUE(info.elf == nullptr);

	// Set them all going and wait for the threads to finish.
	wait = false;
	for (auto thread : threads) {
	thread->join();
	delete thread;
	}

	// Now verify that all of the elf files are exactly the same and valid.
	Elf* elf = info.elf.get();
	ASSERT_TRUE(elf != nullptr);
	EXPECT_TRUE(elf->valid());
	for (size_t i = 0; i < kNumConcurrentThreads; i++) {
	EXPECT_EQ(elf, elf_in_threads[i]) << "Thread " << i << " mismatched.";
	}
	}

	} // namespace unwindstack