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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 https://mozilla.org/MPL/2.0/. */
#include "mozilla/GeckoArgs.h"
namespace mozilla::geckoargs {
#ifdef XP_UNIX
// Table of file handles which have been passed from another process.
// The default mapping is hard-coded here, but can be overridden for platforms
// where that is necessary.
//
// NOTE: If we ever need to inherit more than 15 handles during process
// creation, we will need to extend this static array by adding more unique
// entries.
static int gInitialFileHandles[]{3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17};
void SetPassedFileHandles(Span<int> aFiles) {
MOZ_RELEASE_ASSERT(aFiles.Length() <= std::size(gInitialFileHandles));
for (size_t i = 0; i < std::size(gInitialFileHandles); ++i) {
if (i < aFiles.Length()) {
gInitialFileHandles[i] = aFiles[i];
} else {
gInitialFileHandles[i] = -1;
}
}
}
void SetPassedFileHandles(std::vector<UniqueFileHandle>&& aFiles) {
MOZ_RELEASE_ASSERT(aFiles.size() <= std::size(gInitialFileHandles));
for (size_t i = 0; i < std::size(gInitialFileHandles); ++i) {
if (i < aFiles.size()) {
gInitialFileHandles[i] = aFiles[i].release();
} else {
gInitialFileHandles[i] = -1;
}
}
}
void AddToFdsToRemap(const ChildProcessArgs& aArgs,
std::vector<std::pair<int, int>>& aFdsToRemap) {
MOZ_RELEASE_ASSERT(aArgs.mFiles.size() <= std::size(gInitialFileHandles));
for (size_t i = 0; i < aArgs.mFiles.size(); ++i) {
aFdsToRemap.push_back(
std::pair{aArgs.mFiles[i].get(), gInitialFileHandles[i]});
}
}
#endif
#ifdef XP_DARWIN
// Table of mach send rights which have been sent by the parent process.
static mach_port_t gMachSendRights[kMaxPassedMachSendRights] = {MACH_PORT_NULL};
void SetPassedMachSendRights(std::vector<UniqueMachSendRight>&& aSendRights) {
MOZ_RELEASE_ASSERT(aSendRights.size() <= std::size(gMachSendRights));
for (size_t i = 0; i < aSendRights.size(); ++i) {
gMachSendRights[i] = aSendRights[i].release();
}
}
#endif
static void ParseHandleArgument(uint32_t aArg, UniqueFileHandle& aOutHandle) {
#ifdef XP_WIN
// Recover the pointer-sized HANDLE from the 32-bit argument received over IPC
// by sign-extending to the full pointer width. See `SerializeHandleArgument`
// for an explanation.
aOutHandle = UniqueFileHandle{reinterpret_cast<HANDLE>(
static_cast<uintptr_t>(static_cast<int32_t>(aArg)))};
#else
// See the comment on gInitialFileHandles for an explanation of the
// behaviour here.
MOZ_RELEASE_ASSERT(aArg < std::size(gInitialFileHandles));
aOutHandle = UniqueFileHandle{std::exchange(gInitialFileHandles[aArg], -1)};
#endif
}
static Maybe<uint32_t> SerializeHandleArgument(UniqueFileHandle&& aValue,
ChildProcessArgs& aArgs) {
if (aValue) {
#ifdef XP_WIN
// On Windows, we'll inherit the handle by-identity, so pass down the
// HANDLE's value. Handles are always 32-bits (potentially sign-extended),
// so we explicitly truncate them before sending over IPC.
HANDLE value = aValue.get();
uint32_t arg = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(value));
#else
uint32_t arg = static_cast<uint32_t>(aArgs.mFiles.size());
#endif
aArgs.mFiles.push_back(std::move(aValue));
return Some(arg);
}
return Nothing();
}
template <>
Maybe<UniqueFileHandle> CommandLineArg<UniqueFileHandle>::GetCommon(
const char* aMatch, int& aArgc, char** aArgv, const CheckArgFlag aFlags) {
if (Maybe<uint32_t> arg =
CommandLineArg<uint32_t>::GetCommon(aMatch, aArgc, aArgv, aFlags)) {
UniqueFileHandle h;
ParseHandleArgument(*arg, h);
return Some(std::move(h));
}
return Nothing();
}
template <>
void CommandLineArg<UniqueFileHandle>::PutCommon(const char* aName,
UniqueFileHandle aValue,
ChildProcessArgs& aArgs) {
if (auto arg = SerializeHandleArgument(std::move(aValue), aArgs)) {
CommandLineArg<uint32_t>::PutCommon(aName, *arg, aArgs);
}
}
#ifdef XP_DARWIN
static void ParseHandleArgument(uint32_t aArg,
UniqueMachSendRight& aOutHandle) {
MOZ_RELEASE_ASSERT(aArg < std::size(gMachSendRights));
aOutHandle =
UniqueMachSendRight{std::exchange(gMachSendRights[aArg], MACH_PORT_NULL)};
}
static Maybe<uint32_t> SerializeHandleArgument(UniqueMachSendRight&& aValue,
ChildProcessArgs& aArgs) {
if (aValue) {
aArgs.mSendRights.push_back(std::move(aValue));
return Some(static_cast<uint32_t>(aArgs.mSendRights.size() - 1));
}
return Nothing();
}
template <>
Maybe<UniqueMachSendRight> CommandLineArg<UniqueMachSendRight>::GetCommon(
const char* aMatch, int& aArgc, char** aArgv, const CheckArgFlag aFlags) {
if (Maybe<uint32_t> arg =
CommandLineArg<uint32_t>::GetCommon(aMatch, aArgc, aArgv, aFlags)) {
UniqueMachSendRight h;
ParseHandleArgument(*arg, h);
return Some(std::move(h));
}
return Nothing();
}
template <>
void CommandLineArg<UniqueMachSendRight>::PutCommon(const char* aName,
UniqueMachSendRight aValue,
ChildProcessArgs& aArgs) {
if (auto arg = SerializeHandleArgument(std::move(aValue), aArgs)) {
CommandLineArg<uint32_t>::PutCommon(aName, *arg, aArgs);
}
}
#endif
// Shared memory handles are passed as a (handle, size) pair, which both turn
// into numeric CLI arguments, so it's safe to use ":" as a separator.
constexpr const char* kSharedMemoryHandleSeparator = ":";
template <>
Maybe<ipc::ReadOnlySharedMemoryHandle>
CommandLineArg<ipc::ReadOnlySharedMemoryHandle>::GetCommon(
const char* aMatch, int& aArgc, char** aArgv, const CheckArgFlag aFlags) {
auto arg =
CommandLineArg<const char*>::GetCommon(aMatch, aArgc, aArgv, aFlags);
if (!arg) {
return Nothing();
}
std::string_view str = *arg;
auto position = str.find(kSharedMemoryHandleSeparator);
if (position == std::string_view::npos) {
return Nothing();
}
auto handleId = ParseIntArgument(str.substr(0, position));
auto size = ParseIntArgument(str.substr(position + 1));
if (!handleId || !size) {
return Nothing();
}
ipc::shared_memory::PlatformHandle handle;
ParseHandleArgument(*handleId, handle);
if (!handle) {
return Nothing();
}
mozilla::ipc::ReadOnlySharedMemoryHandle rv;
rv.mHandle = std::move(handle);
rv.SetSize(*size);
return Some(std::move(rv));
}
template <>
void CommandLineArg<ipc::ReadOnlySharedMemoryHandle>::PutCommon(
const char* aName, ipc::ReadOnlySharedMemoryHandle aValue,
ChildProcessArgs& aArgs) {
if (!aValue) {
return;
}
auto size = aValue.Size();
auto handle = std::move(aValue).TakePlatformHandle();
MOZ_ASSERT(handle, "shmem platform handle is invalid");
auto handleId = SerializeHandleArgument(std::move(handle), aArgs);
if (!handleId) {
return;
}
auto arg = std::to_string(*handleId) + kSharedMemoryHandleSeparator +
std::to_string(size);
CommandLineArg<const char*>::PutCommon(aName, arg.c_str(), aArgs);
}
} // namespace mozilla::geckoargs
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