// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "elf_file.h"

#include <limits.h>
#include <stdio.h>
#include <unistd.h>
#include <string>
#include <vector>
#include "debug.h"
#include "elf_traits.h"
#include "testing/gtest/include/gtest/gtest.h"

// Macro stringification.
// https://gcc.gnu.org/onlinedocs/cpp/Stringification.html
#define XSTR(S) STR(S)
#define STR(S) #S

namespace {

void GetDataFilePath(const char* name, std::string* path) {
  std::string data_dir;

  const char* bindir = getenv("bindir");
  if (bindir) {
    data_dir = std::string(bindir);
  } else {
    // Test data is in the gyp INTERMEDIATE_DIR subdirectory of the directory
    // that contains the current binary.
    char path[PATH_MAX];
    memset(path, 0, sizeof(path));
    ASSERT_NE(-1, readlink("/proc/self/exe", path, sizeof(path) - 1));

    data_dir = std::string(path);
    size_t pos = data_dir.rfind('/');
    ASSERT_NE(std::string::npos, pos);

    data_dir.erase(pos + 1);
    data_dir += std::string(XSTR(INTERMEDIATE_DIR));
  }

  *path = data_dir + "/" + name;
}

void OpenRelocsTestFile(const char* name, FILE** stream) {
  std::string path;
  GetDataFilePath(name, &path);

  FILE* testfile = fopen(path.c_str(), "rb");
  ASSERT_FALSE(testfile == NULL);

  FILE* temporary = tmpfile();
  ASSERT_FALSE(temporary == NULL);

  static const size_t buffer_size = 4096;
  unsigned char buffer[buffer_size];

  size_t bytes;
  do {
    bytes = fread(buffer, 1, sizeof(buffer), testfile);
    ASSERT_EQ(bytes, fwrite(buffer, 1, bytes, temporary));
  } while (bytes > 0);

  ASSERT_EQ(0, fclose(testfile));
  ASSERT_EQ(0, fseek(temporary, 0, SEEK_SET));
  ASSERT_EQ(0, lseek(fileno(temporary), 0, SEEK_SET));

  *stream = temporary;
}

void OpenRelocsTestFiles(FILE** relocs_so, FILE** packed_relocs_so) {
  const char* arch = NULL;
  if (ELF::kMachine == EM_ARM) {
    arch = "arm32";
  } else if (ELF::kMachine == EM_AARCH64) {
    arch = "arm64";
  }
  ASSERT_FALSE(arch == NULL);

  const std::string base = std::string("elf_file_unittest_relocs_") + arch;
  const std::string relocs = base + ".so";
  const std::string packed_relocs = base + "_packed.so";

  OpenRelocsTestFile(relocs.c_str(), relocs_so);
  OpenRelocsTestFile(packed_relocs.c_str(), packed_relocs_so);
}

void CloseRelocsTestFile(FILE* temporary) {
  fclose(temporary);
}

void CloseRelocsTestFiles(FILE* relocs_so, FILE* packed_relocs_so) {
  CloseRelocsTestFile(relocs_so);
  CloseRelocsTestFile(packed_relocs_so);
}

void CheckFileContentsEqual(FILE* first, FILE* second) {
  ASSERT_EQ(0, fseek(first, 0, SEEK_SET));
  ASSERT_EQ(0, fseek(second, 0, SEEK_SET));

  static const size_t buffer_size = 4096;
  unsigned char first_buffer[buffer_size];
  unsigned char second_buffer[buffer_size];

  do {
    size_t first_read = fread(first_buffer, 1, sizeof(first_buffer), first);
    size_t second_read = fread(second_buffer, 1, sizeof(second_buffer), second);

    EXPECT_EQ(first_read, second_read);
    EXPECT_EQ(0, memcmp(first_buffer, second_buffer, first_read));
  } while (!feof(first) && !feof(second));

  EXPECT_TRUE(feof(first) && feof(second));
}

}  // namespace

namespace relocation_packer {

TEST(ElfFile, PackRelocations) {
  ASSERT_NE(EV_NONE, elf_version(EV_CURRENT));

  FILE* relocs_so = NULL;
  FILE* packed_relocs_so = NULL;
  OpenRelocsTestFiles(&relocs_so, &packed_relocs_so);
  if (HasFatalFailure())
    return;

  ElfFile elf_file(fileno(relocs_so));

  // Ensure unpacking fails (not packed).
  EXPECT_FALSE(elf_file.UnpackRelocations());

  // Pack relocations, and check files are now identical.
  EXPECT_TRUE(elf_file.PackRelocations());
  CheckFileContentsEqual(relocs_so, packed_relocs_so);

  CloseRelocsTestFiles(relocs_so, packed_relocs_so);
}

TEST(ElfFile, UnpackRelocations) {
  ASSERT_NE(EV_NONE, elf_version(EV_CURRENT));

  FILE* relocs_so = NULL;
  FILE* packed_relocs_so = NULL;
  OpenRelocsTestFiles(&relocs_so, &packed_relocs_so);
  if (HasFatalFailure())
    return;

  ElfFile elf_file(fileno(packed_relocs_so));

  // Ensure packing fails (already packed).
  EXPECT_FALSE(elf_file.PackRelocations());

  // Unpack golden relocations, and check files are now identical.
  EXPECT_TRUE(elf_file.UnpackRelocations());
  CheckFileContentsEqual(packed_relocs_so, relocs_so);

  CloseRelocsTestFiles(relocs_so, packed_relocs_so);
}

}  // namespace relocation_packer