gecko-dev/ipc/glue/Transport_posix.cpp
Jed Davis 0e88912e37 Bug 1632687 - Part 3: Introduce an OS-dependent ChannelId type to reflect that Unix doesn't use channel IDs. r=mccr8
The Chromium-derived IPC code was, as far as I can tell, originally
designed for Windows and assumed that channels would be named pipes,
managed and connected to via `std::wstring` paths.  The port to Unix,
however, used unnamed `socketpair()` and passed them directly from
process to process, so it has no use for these channel IDs...  but it
still computes and propagates them, even though they're not used, using
deprecated wide-string APIs.

This patch introduces a typedef for an abstract channel ID, which is a
`wstring` on Windows and an empty struct on Unix, to allow removing the
string code where it's not needed without needing to completely redesign
the channel abstraction.

Differential Revision: https://phabricator.services.mozilla.com/D72260
2020-07-22 19:04:48 +00:00

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/* -*- 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 <unistd.h>
#include <string>
#include "base/eintr_wrapper.h"
#include "mozilla/ipc/Transport.h"
#include "mozilla/ipc/FileDescriptor.h"
#include "ProtocolUtils.h"
using base::ProcessHandle;
namespace mozilla {
namespace ipc {
nsresult CreateTransport(base::ProcessId aProcIdOne, TransportDescriptor* aOne,
TransportDescriptor* aTwo) {
auto id = IPC::Channel::GenerateVerifiedChannelID();
// Use MODE_SERVER to force creation of the socketpair
Transport t(id, Transport::MODE_SERVER, nullptr);
int fd1 = t.GetFileDescriptor();
int fd2, dontcare;
t.GetClientFileDescriptorMapping(&fd2, &dontcare);
if (fd1 < 0 || fd2 < 0) {
return NS_ERROR_TRANSPORT_INIT;
}
// The Transport closes these fds when it goes out of scope, so we
// dup them here
fd1 = dup(fd1);
if (fd1 < 0) {
AnnotateCrashReportWithErrno(
CrashReporter::Annotation::IpcCreateTransportDupErrno, errno);
}
fd2 = dup(fd2);
if (fd2 < 0) {
AnnotateCrashReportWithErrno(
CrashReporter::Annotation::IpcCreateTransportDupErrno, errno);
}
if (fd1 < 0 || fd2 < 0) {
IGNORE_EINTR(close(fd1));
IGNORE_EINTR(close(fd2));
return NS_ERROR_DUPLICATE_HANDLE;
}
aOne->mFd = base::FileDescriptor(fd1, true /*close after sending*/);
aTwo->mFd = base::FileDescriptor(fd2, true /*close after sending*/);
return NS_OK;
}
UniquePtr<Transport> OpenDescriptor(const TransportDescriptor& aTd,
Transport::Mode aMode) {
return MakeUnique<Transport>(aTd.mFd.fd, aMode, nullptr);
}
UniquePtr<Transport> OpenDescriptor(const FileDescriptor& aFd,
Transport::Mode aMode) {
auto rawFD = aFd.ClonePlatformHandle();
return MakeUnique<Transport>(rawFD.release(), aMode, nullptr);
}
TransportDescriptor DuplicateDescriptor(const TransportDescriptor& aTd) {
TransportDescriptor result = aTd;
result.mFd.fd = dup(aTd.mFd.fd);
if (result.mFd.fd == -1) {
AnnotateSystemError();
}
MOZ_RELEASE_ASSERT(result.mFd.fd != -1, "DuplicateDescriptor failed");
return result;
}
void CloseDescriptor(const TransportDescriptor& aTd) { close(aTd.mFd.fd); }
} // namespace ipc
} // namespace mozilla