gecko-dev/ipc/glue/FileDescriptor.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "FileDescriptor.h"

#include "mozilla/Assertions.h"
#include "mozilla/Move.h"
#include "nsDebug.h"

#ifdef XP_WIN

#  include <windows.h>
#  include "ProtocolUtils.h"
#  define INVALID_HANDLE INVALID_HANDLE_VALUE

#else  // XP_WIN

#  include <unistd.h>

#  ifndef OS_POSIX
#    define OS_POSIX
#  endif

#  include "base/eintr_wrapper.h"
#  define INVALID_HANDLE -1

#endif  // XP_WIN

namespace mozilla {
namespace ipc {

FileDescriptor::FileDescriptor() : mHandle(INVALID_HANDLE) {}

FileDescriptor::FileDescriptor(const FileDescriptor& aOther)
    : mHandle(INVALID_HANDLE) {
  Assign(aOther);
}

FileDescriptor::FileDescriptor(FileDescriptor&& aOther)
    : mHandle(INVALID_HANDLE) {
  *this = std::move(aOther);
}

FileDescriptor::FileDescriptor(PlatformHandleType aHandle)
    : mHandle(INVALID_HANDLE) {
  mHandle = Clone(aHandle);
}

FileDescriptor::FileDescriptor(const IPDLPrivate&, const PickleType& aPickle)
    : mHandle(INVALID_HANDLE) {
#ifdef XP_WIN
  mHandle = aPickle;
#else
  mHandle = aPickle.fd;
#endif
}

FileDescriptor::~FileDescriptor() { Close(); }

FileDescriptor& FileDescriptor::operator=(const FileDescriptor& aOther) {
  if (this != &aOther) {
    Assign(aOther);
  }
  return *this;
}

FileDescriptor& FileDescriptor::operator=(FileDescriptor&& aOther) {
  if (this != &aOther) {
    Close();
    mHandle = aOther.mHandle;
    aOther.mHandle = INVALID_HANDLE;
  }
  return *this;
}

bool FileDescriptor::IsValid() const { return IsValid(mHandle); }

void FileDescriptor::Assign(const FileDescriptor& aOther) {
  Close();
  mHandle = Clone(aOther.mHandle);
}

void FileDescriptor::Close() {
  Close(mHandle);
  mHandle = INVALID_HANDLE;
}

FileDescriptor::PickleType FileDescriptor::ShareTo(
    const FileDescriptor::IPDLPrivate&,
    FileDescriptor::ProcessId aTargetPid) const {
  PlatformHandleType newHandle;
#ifdef XP_WIN
  if (IsValid()) {
    if (mozilla::ipc::DuplicateHandle(mHandle, aTargetPid, &newHandle, 0,
                                      DUPLICATE_SAME_ACCESS)) {
      return newHandle;
    }
    NS_WARNING("Failed to duplicate file handle for other process!");
  }
  return INVALID_HANDLE;
#else  // XP_WIN
  if (IsValid()) {
    newHandle = dup(mHandle);
    if (IsValid(newHandle)) {
      return base::FileDescriptor(newHandle, /* auto_close */ true);
    }
    NS_WARNING("Failed to duplicate file handle for other process!");
  }
  return base::FileDescriptor();
#endif

  MOZ_CRASH("Must not get here!");
}

FileDescriptor::UniquePlatformHandle FileDescriptor::ClonePlatformHandle()
    const {
  return UniquePlatformHandle(Clone(mHandle));
}

bool FileDescriptor::operator==(const FileDescriptor& aOther) const {
  return mHandle == aOther.mHandle;
}

// static
bool FileDescriptor::IsValid(PlatformHandleType aHandle) {
  return aHandle != INVALID_HANDLE;
}

// static
FileDescriptor::PlatformHandleType FileDescriptor::Clone(
    PlatformHandleType aHandle) {
  if (!IsValid(aHandle)) {
    return INVALID_HANDLE;
  }
  FileDescriptor::PlatformHandleType newHandle;
#ifdef XP_WIN
  if (::DuplicateHandle(GetCurrentProcess(), aHandle, GetCurrentProcess(),
                        &newHandle, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
#else  // XP_WIN
  if ((newHandle = dup(aHandle)) != INVALID_HANDLE) {
#endif
    return newHandle;
  }
  NS_WARNING("Failed to duplicate file handle for current process!");
  return INVALID_HANDLE;
}

// static
void FileDescriptor::Close(PlatformHandleType aHandle) {
  if (IsValid(aHandle)) {
#ifdef XP_WIN
    if (!CloseHandle(aHandle)) {
      NS_WARNING("Failed to close file handle for current process!");
    }
#else  // XP_WIN
    IGNORE_EINTR(close(aHandle));
#endif
  }
}

FileDescriptor::PlatformHandleHelper::PlatformHandleHelper(
    FileDescriptor::PlatformHandleType aHandle)
    : mHandle(aHandle) {}

FileDescriptor::PlatformHandleHelper::PlatformHandleHelper(std::nullptr_t)
    : mHandle(INVALID_HANDLE) {}

bool FileDescriptor::PlatformHandleHelper::operator!=(std::nullptr_t) const {
  return mHandle != INVALID_HANDLE;
}

FileDescriptor::PlatformHandleHelper::
operator FileDescriptor::PlatformHandleType() const {
  return mHandle;
}

#ifdef XP_WIN
FileDescriptor::PlatformHandleHelper::operator std::intptr_t() const {
  return reinterpret_cast<std::intptr_t>(mHandle);
}
#endif

void FileDescriptor::PlatformHandleDeleter::operator()(
    FileDescriptor::PlatformHandleHelper aHelper) {
  FileDescriptor::Close(aHelper);
}

void IPDLParamTraits<FileDescriptor>::Write(IPC::Message* aMsg,
                                            IProtocol* aActor,
                                            const FileDescriptor& aParam) {
  FileDescriptor::PickleType pfd =
      aParam.ShareTo(FileDescriptor::IPDLPrivate(), aActor->OtherPid());
  WriteIPDLParam(aMsg, aActor, pfd);
}

bool IPDLParamTraits<FileDescriptor>::Read(const IPC::Message* aMsg,
                                           PickleIterator* aIter,
                                           IProtocol* aActor,
                                           FileDescriptor* aResult) {
  FileDescriptor::PickleType pfd;
  if (!ReadIPDLParam(aMsg, aIter, aActor, &pfd)) {
    return false;
  }

  *aResult = FileDescriptor(FileDescriptor::IPDLPrivate(), pfd);
  if (!aResult->IsValid()) {
    printf_stderr("IPDL protocol Error: Received an invalid file descriptor\n");
  }
  return true;
}

}  // namespace ipc
}  // namespace mozilla