elf_image_reader_test.cc | Explore in Territory

// Copyright 2017 The Crashpad Authors
//
// 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 "snapshot/elf/elf_image_reader.h"

#include <dlfcn.h>
#include <link.h>
#include <unistd.h>

#include "build/build_config.h"
#include "gtest/gtest.h"
#include "test/multiprocess_exec.h"
#include "test/process_type.h"
#include "test/scoped_module_handle.h"
#include "test/test_paths.h"
#include "util/file/file_io.h"
#include "util/misc/address_types.h"
#include "util/misc/elf_note_types.h"
#include "util/misc/from_pointer_cast.h"
#include "util/process/process_memory_native.h"

#if BUILDFLAG(IS_FUCHSIA)
#include <lib/zx/process.h>

#include "base/fuchsia/fuchsia_logging.h"

#elif BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)

#include "test/linux/fake_ptrace_connection.h"
#include "util/linux/auxiliary_vector.h"
#include "util/linux/memory_map.h"

#else

#error Port.

#endif  // BUILDFLAG(IS_FUCHSIA)

extern "C" {
__attribute__((visibility("default"))) void ElfImageReaderTestExportedSymbol() { … }
}  // extern "C"

namespace crashpad {
namespace test {
namespace {

#if BUILDFLAG(IS_FUCHSIA)

void LocateExecutable(const ProcessType& process,
                      ProcessMemory* memory,
                      VMAddress* elf_address) {
  uintptr_t debug_address;
  zx_status_t status = process->get_property(
      ZX_PROP_PROCESS_DEBUG_ADDR, &debug_address, sizeof(debug_address));
  ASSERT_EQ(status, ZX_OK)
      << "zx_object_get_property: ZX_PROP_PROCESS_DEBUG_ADDR";
  // Can be 0 if requested before the loader has loaded anything.
  EXPECT_NE(debug_address, 0u);

  constexpr auto k_r_debug_map_offset = offsetof(r_debug, r_map);
  uintptr_t map;
  ASSERT_TRUE(
      memory->Read(debug_address + k_r_debug_map_offset, sizeof(map), &map))
      << "read link_map";

  constexpr auto k_link_map_addr_offset = offsetof(link_map, l_addr);
  uintptr_t base;
  ASSERT_TRUE(memory->Read(map + k_link_map_addr_offset, sizeof(base), &base))
      << "read base";

  *elf_address = base;
}

#elif BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)

void LocateExecutable(PtraceConnection* connection,
                      ProcessMemory* memory,
                      VMAddress* elf_address) { … }

#endif  // BUILDFLAG(IS_FUCHSIA)

void ExpectSymbol(ElfImageReader* reader,
                  const std::string& symbol_name,
                  VMAddress expected_symbol_address) { … }

void ReadThisExecutableInTarget(ProcessType process,
                                VMAddress exported_symbol_address) { … }

void ReadLibcInTarget(ProcessType process,
                      VMAddress elf_address,
                      VMAddress getpid_address) { … }

// This test is flaky: https://crbug.com/331953012
TEST(ElfImageReader, DISABLED_MainExecutableSelf) { … }

CRASHPAD_CHILD_TEST_MAIN(ReadExecutableChild) { … }

class ReadExecutableChildTest : public MultiprocessExec { … };

TEST(ElfImageReader, MainExecutableChild) { … }

TEST(ElfImageReader, OneModuleSelf) { … }

CRASHPAD_CHILD_TEST_MAIN(ReadLibcChild) { … }

class ReadLibcChildTest : public MultiprocessExec { … };

TEST(ElfImageReader, OneModuleChild) { … }

#if BUILDFLAG(IS_FUCHSIA)

// crashpad_snapshot_test_both_dt_hash_styles is specially built and forced to
// include both .hash and .gnu.hash sections. Linux, Android, and Fuchsia have
// different defaults for which of these sections should be included; this test
// confirms that we get the same count from both sections.
//
// TODO(scottmg): Investigation in https://crrev.com/c/876879 resulted in
// realizing that ld.bfd does not emit a .gnu.hash that is very useful for this
// purpose when there's 0 exported entries in the module. This is not likely to
// be too important, as there's little need to look up non-exported symbols.
// However, it makes this test not work on Linux, where the default build uses
// ld.bfd. On Fuchsia, the only linker in use is lld, and it generates the
// expected .gnu.hash. So, for now, this test is only run on Fuchsia, not Linux.
//
// TODO(scottmg): Separately, the location of the ELF on Android needs some
// work, and then the test could also be enabled there.
TEST(ElfImageReader, DtHashAndDtGnuHashMatch) {
  base::FilePath module_path =
      TestPaths::BuildArtifact(FILE_PATH_LITERAL("snapshot"),
                               FILE_PATH_LITERAL("both_dt_hash_styles"),
                               TestPaths::FileType::kLoadableModule);
  // TODO(scottmg): Remove this when upstream Fuchsia bug ZX-1619 is resolved.
  // See also explanation in build/run_tests.py for Fuchsia .so files.
  module_path = module_path.BaseName();
  ScopedModuleHandle module(
      dlopen(module_path.value().c_str(), RTLD_LAZY | RTLD_LOCAL));
  ASSERT_TRUE(module.valid()) << "dlopen " << module_path.value() << ": "
                              << dlerror();

#if defined(ARCH_CPU_64_BITS)
  constexpr bool am_64_bit = true;
#else
  constexpr bool am_64_bit = false;
#endif  // ARCH_CPU_64_BITS

  ProcessMemoryNative memory;
  ASSERT_TRUE(memory.Initialize(GetSelfProcess()));
  ProcessMemoryRange range;
  ASSERT_TRUE(range.Initialize(&memory, am_64_bit));

  struct link_map* lm = reinterpret_cast<struct link_map*>(module.get());

  ElfImageReader reader;
  ASSERT_TRUE(reader.Initialize(range, lm->l_addr));

  VMSize from_dt_hash;
  ASSERT_TRUE(reader.GetNumberOfSymbolEntriesFromDtHash(&from_dt_hash));

  VMSize from_dt_gnu_hash;
  ASSERT_TRUE(reader.GetNumberOfSymbolEntriesFromDtGnuHash(&from_dt_gnu_hash));

  EXPECT_EQ(from_dt_hash, from_dt_gnu_hash);
}

#endif  // BUILDFLAG(IS_FUCHSIA)

}  // namespace
}  // namespace test
}  // namespace crashpad
chromium/third_party/crashpad/crashpad/snapshot/elf/elf_image_reader_test.cc
