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

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "mojo/core/embedder/embedder.h"

#include <stddef.h>
#include <stdint.h>
#include <string.h>

#include <utility>

#include "base/base_paths.h"
#include "base/command_line.h"
#include "base/files/file.h"
#include "base/functional/bind.h"
#include "base/memory/ptr_util.h"
#include "base/memory/read_only_shared_memory_region.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "base/memory/writable_shared_memory_region.h"
#include "base/notreached.h"
#include "base/path_service.h"
#include "base/rand_util.h"
#include "base/run_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/synchronization/waitable_event.h"
#include "base/test/test_timeouts.h"
#include "build/build_config.h"
#include "mojo/buildflags.h"
#include "mojo/core/embedder/embedder.h"
#include "mojo/core/ipcz_driver/shared_buffer.h"
#include "mojo/core/test/mojo_test_base.h"
#include "mojo/public/c/system/core.h"
#include "mojo/public/cpp/system/handle.h"
#include "mojo/public/cpp/system/message_pipe.h"
#include "mojo/public/cpp/system/platform_handle.h"
#include "mojo/public/cpp/system/wait.h"
#include "testing/gtest/include/gtest/gtest.h"

#if BUILDFLAG(MOJO_SUPPORT_LEGACY_CORE)
#include "mojo/core/core.h"
#include "mojo/core/shared_buffer_dispatcher.h"
#endif

namespace mojo::core {
namespace {

template <typename T>
MojoResult CreateSharedBufferFromRegion(T&& region, MojoHandle* handle) {
  if (IsMojoIpczEnabled()) {
    *handle = ipcz_driver::SharedBuffer::Box(
        ipcz_driver::SharedBuffer::MakeForRegion(std::move(region)));
    return MOJO_RESULT_OK;
  }

#if BUILDFLAG(MOJO_SUPPORT_LEGACY_CORE)
  scoped_refptr<SharedBufferDispatcher> buffer;
  MojoResult result =
      SharedBufferDispatcher::CreateFromPlatformSharedMemoryRegion(
          T::TakeHandleForSerialization(std::forward<T>(region)), &buffer);
  if (result != MOJO_RESULT_OK)
    return result;

  *handle = Core::Get()->AddDispatcher(std::move(buffer));
  return MOJO_RESULT_OK;
#else
  NOTREACHED();
#endif
}

template <typename T>
MojoResult ExtractRegionFromSharedBuffer(MojoHandle handle, T* region) {
  base::subtle::PlatformSharedMemoryRegion platform_region;
  if (IsMojoIpczEnabled()) {
    platform_region =
        std::move(ipcz_driver::SharedBuffer::Unbox(handle)->region());
  } else {
#if BUILDFLAG(MOJO_SUPPORT_LEGACY_CORE)
    scoped_refptr<Dispatcher> dispatcher =
        Core::Get()->GetAndRemoveDispatcher(handle);
    if (!dispatcher || dispatcher->GetType() != Dispatcher::Type::SHARED_BUFFER)
      return MOJO_RESULT_INVALID_ARGUMENT;

    auto* buffer = static_cast<SharedBufferDispatcher*>(dispatcher.get());
    platform_region = buffer->PassPlatformSharedMemoryRegion();
#else
    NOTREACHED();
#endif
  }

  *region = T::Deserialize(std::move(platform_region));
  return MOJO_RESULT_OK;
}

// The multiprocess tests that use these don't compile on iOS.
#if !BUILDFLAG(IS_IOS)
const char kHelloWorld[] = "hello world";
const char kByeWorld[] = "bye world";
#endif

using EmbedderTest = test::MojoTestBase;

TEST_F(EmbedderTest, ChannelBasic) {
  MojoHandle server_mp, client_mp;
  CreateMessagePipe(&server_mp, &client_mp);

  const std::string kHello = "hello";

  // We can write to a message pipe handle immediately.
  WriteMessage(server_mp, kHello);
  EXPECT_EQ(kHello, ReadMessage(client_mp));

  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(server_mp));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp));
}

// Verifies that a MP with pending messages to be written can be sent and the
// pending messages aren't dropped.
TEST_F(EmbedderTest, SendMessagePipeWithWriteQueue) {
  MojoHandle server_mp, client_mp;
  CreateMessagePipe(&server_mp, &client_mp);

  MojoHandle server_mp2, client_mp2;
  CreateMessagePipe(&server_mp2, &client_mp2);

  static const size_t kNumMessages = 1001;
  for (size_t i = 1; i <= kNumMessages; i++)
    WriteMessage(client_mp2, std::string(i, 'A' + (i % 26)));

  // Now send client2.
  WriteMessageWithHandles(server_mp, "hey", &client_mp2, 1);
  client_mp2 = MOJO_HANDLE_INVALID;

  // Read client2 just so we can close it later.
  EXPECT_EQ("hey", ReadMessageWithHandles(client_mp, &client_mp2, 1));
  EXPECT_NE(MOJO_HANDLE_INVALID, client_mp2);

  // Now verify that all the messages that were written were sent correctly.
  for (size_t i = 1; i <= kNumMessages; i++)
    ASSERT_EQ(std::string(i, 'A' + (i % 26)), ReadMessage(server_mp2));

  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(server_mp2));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp2));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(server_mp));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp));
}

TEST_F(EmbedderTest, ChannelsHandlePassing) {
  MojoHandle server_mp, client_mp;
  CreateMessagePipe(&server_mp, &client_mp);
  EXPECT_NE(server_mp, MOJO_HANDLE_INVALID);
  EXPECT_NE(client_mp, MOJO_HANDLE_INVALID);

  MojoHandle h0, h1;
  CreateMessagePipe(&h0, &h1);

  // Write a message to |h0| (attaching nothing).
  const std::string kHello = "hello";
  WriteMessage(h0, kHello);

  // Write one message to |server_mp|, attaching |h1|.
  const std::string kWorld = "world!!!";
  WriteMessageWithHandles(server_mp, kWorld, &h1, 1);
  h1 = MOJO_HANDLE_INVALID;

  // Write another message to |h0|.
  const std::string kFoo = "foo";
  WriteMessage(h0, kFoo);

  // Wait for |client_mp| to become readable and read a message from it.
  EXPECT_EQ(kWorld, ReadMessageWithHandles(client_mp, &h1, 1));
  EXPECT_NE(h1, MOJO_HANDLE_INVALID);

  // Wait for |h1| to become readable and read a message from it.
  EXPECT_EQ(kHello, ReadMessage(h1));

  // Wait for |h1| to become readable (again) and read its second message.
  EXPECT_EQ(kFoo, ReadMessage(h1));

  // Write a message to |h1|.
  const std::string kBarBaz = "barbaz";
  WriteMessage(h1, kBarBaz);

  // Wait for |h0| to become readable and read a message from it.
  EXPECT_EQ(kBarBaz, ReadMessage(h0));

  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(server_mp));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(h0));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(h1));
}

// The sequence of messages sent is:
//       server_mp   client_mp   mp0         mp1         mp2         mp3
//   1.  "hello"
//   2.              "world!"
//   3.                          "FOO"
//   4.  "Bar"+mp1
//   5.  (close)
//   6.              (close)
//   7.                                                              "baz"
//   8.                                                              (closed)
//   9.                                      "quux"+mp2
//  10.                          (close)
//  11.                                      (wait/cl.)
//  12.                                                  (wait/cl.)

#if !BUILDFLAG(IS_IOS)

TEST_F(EmbedderTest, MultiprocessChannels) {
  RunTestClient("MultiprocessChannelsClient", [&](MojoHandle server_mp) {
    // 1. Write a message to |server_mp| (attaching nothing).
    WriteMessage(server_mp, "hello");

    // 2. Read a message from |server_mp|.
    EXPECT_EQ("world!", ReadMessage(server_mp));

    // 3. Create a new message pipe (endpoints |mp0| and |mp1|).
    MojoHandle mp0, mp1;
    CreateMessagePipe(&mp0, &mp1);

    // 4. Write something to |mp0|.
    WriteMessage(mp0, "FOO");

    // 5. Write a message to |server_mp|, attaching |mp1|.
    WriteMessageWithHandles(server_mp, "Bar", &mp1, 1);
    mp1 = MOJO_HANDLE_INVALID;

    // 6. Read a message from |mp0|, which should have |mp2| attached.
    MojoHandle mp2 = MOJO_HANDLE_INVALID;
    EXPECT_EQ("quux", ReadMessageWithHandles(mp0, &mp2, 1));

    // 7. Read a message from |mp2|.
    EXPECT_EQ("baz", ReadMessage(mp2));

    // 8. Close |mp0|.
    ASSERT_EQ(MOJO_RESULT_OK, MojoClose(mp0));

    // 9. Tell the client to quit.
    WriteMessage(server_mp, "quit");

    // 10. Wait on |mp2| (which should eventually fail) and then close it.
    MojoHandleSignalsState state;
    ASSERT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
              WaitForSignals(mp2, MOJO_HANDLE_SIGNAL_READABLE, &state));
    ASSERT_EQ(MOJO_HANDLE_SIGNAL_PEER_CLOSED, state.satisfied_signals);
    ASSERT_FALSE(state.satisfiable_signals & MOJO_HANDLE_SIGNAL_READABLE);
    ASSERT_FALSE(state.satisfiable_signals & MOJO_HANDLE_SIGNAL_WRITABLE);

    ASSERT_EQ(MOJO_RESULT_OK, MojoClose(mp2));
  });
}

DEFINE_TEST_CLIENT_TEST_WITH_PIPE(MultiprocessChannelsClient,
                                  EmbedderTest,
                                  client_mp) {
  // 1. Read the first message from |client_mp|.
  EXPECT_EQ("hello", ReadMessage(client_mp));

  // 2. Write a message to |client_mp| (attaching nothing).
  WriteMessage(client_mp, "world!");

  // 4. Read a message from |client_mp|, which should have |mp1| attached.
  MojoHandle mp1;
  EXPECT_EQ("Bar", ReadMessageWithHandles(client_mp, &mp1, 1));

  // 5. Create a new message pipe (endpoints |mp2| and |mp3|).
  MojoHandle mp2, mp3;
  CreateMessagePipe(&mp2, &mp3);

  // 6. Write a message to |mp3|.
  WriteMessage(mp3, "baz");

  // 7. Close |mp3|.
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(mp3));

  // 8. Write a message to |mp1|, attaching |mp2|.
  WriteMessageWithHandles(mp1, "quux", &mp2, 1);
  mp2 = MOJO_HANDLE_INVALID;

  // 9. Read a message from |mp1|.
  EXPECT_EQ("FOO", ReadMessage(mp1));

  EXPECT_EQ("quit", ReadMessage(client_mp));

  // 10. Wait on |mp1| (which should eventually fail) and then close it.
  MojoHandleSignalsState state;
  ASSERT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
            WaitForSignals(mp1, MOJO_HANDLE_SIGNAL_READABLE, &state));
  ASSERT_EQ(MOJO_HANDLE_SIGNAL_PEER_CLOSED, state.satisfied_signals);
  ASSERT_FALSE(state.satisfiable_signals & MOJO_HANDLE_SIGNAL_READABLE);
  ASSERT_FALSE(state.satisfiable_signals & MOJO_HANDLE_SIGNAL_WRITABLE);
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(mp1));
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp));
}

TEST_F(EmbedderTest, MultiprocessBaseSharedMemory) {
  RunTestClient("MultiprocessSharedMemoryClient", [&](MojoHandle server_mp) {
    // 1. Create a shared memory region and wrap it as a Mojo object.
    auto shared_memory = base::UnsafeSharedMemoryRegion::Create(123);
    ASSERT_TRUE(shared_memory.IsValid());
    MojoHandle sb1;
    ASSERT_EQ(MOJO_RESULT_OK,
              CreateSharedBufferFromRegion(shared_memory.Duplicate(), &sb1));

    // 2. Map |sb1| and write something into it.
    char* buffer = nullptr;
    ASSERT_EQ(MOJO_RESULT_OK, MojoMapBuffer(sb1, 0, 123, nullptr,
                                            reinterpret_cast<void**>(&buffer)));
    ASSERT_TRUE(buffer);
    memcpy(buffer, kHelloWorld, sizeof(kHelloWorld));

    // 3. Duplicate |sb1| into |sb2| and pass to |server_mp|.
    MojoHandle sb2 = MOJO_HANDLE_INVALID;
    EXPECT_EQ(MOJO_RESULT_OK, MojoDuplicateBufferHandle(sb1, nullptr, &sb2));
    EXPECT_NE(MOJO_HANDLE_INVALID, sb2);
    WriteMessageWithHandles(server_mp, "hello", &sb2, 1);

    // 4. Read a message from |server_mp|.
    EXPECT_EQ("hey", ReadMessage(server_mp));

    // 5. Expect that the contents of the shared buffer have changed.
    EXPECT_EQ(kByeWorld, std::string(buffer));

    // 6. Map the original base::SharedMemory and expect it contains the
    // expected value.
    auto mapping = shared_memory.Map();
    ASSERT_TRUE(mapping.IsValid());
    EXPECT_EQ(kByeWorld, std::string(static_cast<char*>(mapping.memory())));

    ASSERT_EQ(MOJO_RESULT_OK, MojoClose(sb1));

    // Tell the child it's safe to shut down.
    WriteMessage(server_mp, "bye");
  });
}

DEFINE_TEST_CLIENT_TEST_WITH_PIPE(MultiprocessSharedMemoryClient,
                                  EmbedderTest,
                                  client_mp) {
  // 1. Read the first message from |client_mp|, which should have |sb1| which
  // should be a shared buffer handle.
  MojoHandle sb1;
  EXPECT_EQ("hello", ReadMessageWithHandles(client_mp, &sb1, 1));

  // 2. Map |sb1|.
  char* buffer = nullptr;
  ASSERT_EQ(MOJO_RESULT_OK, MojoMapBuffer(sb1, 0, 123, nullptr,
                                          reinterpret_cast<void**>(&buffer)));
  ASSERT_TRUE(buffer);

  // 3. Ensure |buffer| contains the values we expect.
  EXPECT_EQ(kHelloWorld, std::string(buffer));

  // 4. Write into |buffer| and send a message back.
  memcpy(buffer, kByeWorld, sizeof(kByeWorld));
  WriteMessage(client_mp, "hey");

  // 5. Extract the shared memory handle and ensure we can map it and read the
  // contents.
  base::UnsafeSharedMemoryRegion shared_memory;
  ASSERT_EQ(MOJO_RESULT_OK, ExtractRegionFromSharedBuffer(sb1, &shared_memory));
  auto mapping = shared_memory.Map();
  ASSERT_TRUE(mapping.IsValid());
  EXPECT_NE(buffer, mapping.memory());
  EXPECT_EQ(kByeWorld, std::string(static_cast<char*>(mapping.memory())));

  EXPECT_EQ("bye", ReadMessage(client_mp));

  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp));
}

#if BUILDFLAG(IS_MAC)

enum class HandleType {
  POSIX,
  MACH,
};

const HandleType kTestHandleTypes[] = {
    HandleType::MACH, HandleType::POSIX, HandleType::POSIX, HandleType::MACH,
};

// Test that we can mix file descriptors and mach port handles.
TEST_F(EmbedderTest, MultiprocessMixMachAndFds) {
  const size_t kShmSize = 1234;
  RunTestClient("MultiprocessMixMachAndFdsClient", [&](MojoHandle server_mp) {
    // 1. Create fds or Mach objects and mojo handles from them.
    MojoHandle platform_handles[std::size(kTestHandleTypes)];
    for (size_t i = 0; i < std::size(kTestHandleTypes); i++) {
      const auto type = kTestHandleTypes[i];
      PlatformHandle scoped_handle;
      if (type == HandleType::POSIX) {
        // The easiest source of fds is opening /dev/null.
        base::File file(base::FilePath("/dev/null"),
                        base::File::FLAG_OPEN | base::File::FLAG_WRITE);
        ASSERT_TRUE(file.IsValid());
        scoped_handle = PlatformHandle(base::ScopedFD(file.TakePlatformFile()));
        ASSERT_TRUE(scoped_handle.is_valid_fd());
      } else {
        auto shared_memory = base::UnsafeSharedMemoryRegion::Create(kShmSize);
        ASSERT_TRUE(shared_memory.IsValid());
        auto shm_handle =
            base::UnsafeSharedMemoryRegion::TakeHandleForSerialization(
                std::move(shared_memory))
                .PassPlatformHandle();
        scoped_handle = PlatformHandle(std::move(shm_handle));
        ASSERT_TRUE(scoped_handle.is_valid_mach_port());
      }
      platform_handles[i] =
          WrapPlatformHandle(std::move(scoped_handle)).release().value();
    }

    // 2. Send all the handles to the child.
    WriteMessageWithHandles(server_mp, "hello", platform_handles,
                            std::size(kTestHandleTypes));

    // 3. Read a message from |server_mp|.
    EXPECT_EQ("bye", ReadMessage(server_mp));
  });
}

DEFINE_TEST_CLIENT_TEST_WITH_PIPE(MultiprocessMixMachAndFdsClient,
                                  EmbedderTest,
                                  client_mp) {
  const int kNumHandles = std::size(kTestHandleTypes);
  MojoHandle platform_handles[kNumHandles];

  // 1. Read from |client_mp|, which should have a message containing
  // |kNumHandles| handles.
  EXPECT_EQ("hello",
            ReadMessageWithHandles(client_mp, platform_handles, kNumHandles));

  // 2. Extract each handle, and verify the type.
  for (int i = 0; i < kNumHandles; i++) {
    const auto type = kTestHandleTypes[i];
    PlatformHandle scoped_handle =
        UnwrapPlatformHandle(ScopedHandle(Handle(platform_handles[i])));
    if (type == HandleType::POSIX) {
      EXPECT_TRUE(scoped_handle.is_valid_fd());
    } else {
      EXPECT_TRUE(scoped_handle.is_valid_mach_port());
    }
  }

  // 3. Say bye!
  WriteMessage(client_mp, "bye");
  ASSERT_EQ(MOJO_RESULT_OK, MojoClose(client_mp));
}

#endif  // BUILDFLAG(IS_MAC)

#endif  // !BUILDFLAG(IS_IOS)

}  // namespace
}  // namespace mojo::core