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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "elf_file.h"
     18 
     19 #include "base/stringprintf.h"
     20 #include "base/unix_file/fd_file.h"
     21 #include "common_compiler_test.h"
     22 #include "elf_file.h"
     23 #include "elf_file_impl.h"
     24 #include "elf_writer_quick.h"
     25 #include "oat.h"
     26 #include "utils.h"
     27 
     28 namespace art {
     29 
     30 class ElfWriterTest : public CommonCompilerTest {
     31  protected:
     32   virtual void SetUp() {
     33     ReserveImageSpace();
     34     CommonCompilerTest::SetUp();
     35   }
     36 };
     37 
     38 #define EXPECT_ELF_FILE_ADDRESS(ef, expected_value, symbol_name, build_map) \
     39   do { \
     40     void* addr = reinterpret_cast<void*>(ef->FindSymbolAddress(SHT_DYNSYM, \
     41                                                                symbol_name, \
     42                                                                build_map)); \
     43     EXPECT_NE(nullptr, addr); \
     44     EXPECT_LT(static_cast<uintptr_t>(ART_BASE_ADDRESS), reinterpret_cast<uintptr_t>(addr)); \
     45     if (expected_value == nullptr) { \
     46       expected_value = addr; \
     47     }                        \
     48     EXPECT_EQ(expected_value, addr); \
     49     EXPECT_EQ(expected_value, ef->FindDynamicSymbolAddress(symbol_name)); \
     50   } while (false)
     51 
     52 TEST_F(ElfWriterTest, dlsym) {
     53   std::string elf_location = GetCoreOatLocation();
     54   std::string elf_filename = GetSystemImageFilename(elf_location.c_str(), kRuntimeISA);
     55   LOG(INFO) << "elf_filename=" << elf_filename;
     56 
     57   UnreserveImageSpace();
     58   void* dl_oatdata = nullptr;
     59   void* dl_oatexec = nullptr;
     60   void* dl_oatlastword = nullptr;
     61 
     62   std::unique_ptr<File> file(OS::OpenFileForReading(elf_filename.c_str()));
     63   ASSERT_TRUE(file.get() != nullptr);
     64   {
     65     std::string error_msg;
     66     std::unique_ptr<ElfFile> ef(ElfFile::Open(file.get(), false, false, &error_msg));
     67     CHECK(ef.get() != nullptr) << error_msg;
     68     EXPECT_ELF_FILE_ADDRESS(ef, dl_oatdata, "oatdata", false);
     69     EXPECT_ELF_FILE_ADDRESS(ef, dl_oatexec, "oatexec", false);
     70     EXPECT_ELF_FILE_ADDRESS(ef, dl_oatlastword, "oatlastword", false);
     71   }
     72   {
     73     std::string error_msg;
     74     std::unique_ptr<ElfFile> ef(ElfFile::Open(file.get(), false, false, &error_msg));
     75     CHECK(ef.get() != nullptr) << error_msg;
     76     EXPECT_ELF_FILE_ADDRESS(ef, dl_oatdata, "oatdata", true);
     77     EXPECT_ELF_FILE_ADDRESS(ef, dl_oatexec, "oatexec", true);
     78     EXPECT_ELF_FILE_ADDRESS(ef, dl_oatlastword, "oatlastword", true);
     79   }
     80   {
     81     std::string error_msg;
     82     std::unique_ptr<ElfFile> ef(ElfFile::Open(file.get(), false, true, &error_msg));
     83     CHECK(ef.get() != nullptr) << error_msg;
     84     CHECK(ef->Load(false, &error_msg)) << error_msg;
     85     EXPECT_EQ(dl_oatdata, ef->FindDynamicSymbolAddress("oatdata"));
     86     EXPECT_EQ(dl_oatexec, ef->FindDynamicSymbolAddress("oatexec"));
     87     EXPECT_EQ(dl_oatlastword, ef->FindDynamicSymbolAddress("oatlastword"));
     88   }
     89 }
     90 
     91 TEST_F(ElfWriterTest, EncodeDecodeOatPatches) {
     92   const std::vector<std::vector<uintptr_t>> test_data {
     93       { 0, 4, 8, 15, 128, 200 },
     94       { 8, 8 + 127 },
     95       { 8, 8 + 128 },
     96       { },
     97   };
     98   for (const auto& patch_locations : test_data) {
     99     constexpr int32_t delta = 0x11235813;
    100 
    101     // Encode patch locations.
    102     std::vector<uint8_t> oat_patches;
    103     ElfWriterQuick32::EncodeOatPatches(patch_locations, &oat_patches);
    104 
    105     // Create buffer to be patched.
    106     std::vector<uint8_t> initial_data(256);
    107     for (size_t i = 0; i < initial_data.size(); i++) {
    108       initial_data[i] = i;
    109     }
    110 
    111     // Patch manually.
    112     std::vector<uint8_t> expected = initial_data;
    113     for (uintptr_t location : patch_locations) {
    114       typedef __attribute__((__aligned__(1))) uint32_t UnalignedAddress;
    115       *reinterpret_cast<UnalignedAddress*>(expected.data() + location) += delta;
    116     }
    117 
    118     // Decode and apply patch locations.
    119     std::vector<uint8_t> actual = initial_data;
    120     ElfFileImpl32::ApplyOatPatches(
    121         oat_patches.data(), oat_patches.data() + oat_patches.size(), delta,
    122         actual.data(), actual.data() + actual.size());
    123 
    124     EXPECT_EQ(expected, actual);
    125   }
    126 }
    127 
    128 }  // namespace art
    129