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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 "ProcessUtils.h"
#include "mozilla/Preferences.h"
#include "mozilla/ipc/GeckoChildProcessHost.h"
#include "mozilla/UniquePtrExtensions.h"
namespace mozilla {
namespace ipc {
SharedPreferenceSerializer::SharedPreferenceSerializer() : mPrefMapSize(0) {
MOZ_COUNT_CTOR(SharedPreferenceSerializer);
}
SharedPreferenceSerializer::~SharedPreferenceSerializer() {
MOZ_COUNT_DTOR(SharedPreferenceSerializer);
}
SharedPreferenceSerializer::SharedPreferenceSerializer(
SharedPreferenceSerializer&& aOther)
: mPrefMapSize(aOther.mPrefMapSize),
mPrefsLength(aOther.mPrefsLength),
mPrefMapHandle(std::move(aOther.mPrefMapHandle)),
mPrefsHandle(std::move(aOther.mPrefsHandle)) {
MOZ_COUNT_CTOR(SharedPreferenceSerializer);
}
bool SharedPreferenceSerializer::SerializeToSharedMemory() {
mPrefMapHandle =
Preferences::EnsureSnapshot(&mPrefMapSize).TakePlatformHandle();
// Serialize the early prefs.
nsAutoCStringN<1024> prefs;
Preferences::SerializePreferences(prefs);
mPrefsLength = prefs.Length();
base::SharedMemory shm;
// Set up the shared memory.
if (!shm.Create(prefs.Length())) {
NS_ERROR("failed to create shared memory in the parent");
return false;
}
if (!shm.Map(prefs.Length())) {
NS_ERROR("failed to map shared memory in the parent");
return false;
}
// Copy the serialized prefs into the shared memory.
memcpy(static_cast<char*>(shm.memory()), prefs.get(), mPrefsLength);
mPrefsHandle = shm.TakeHandle();
return true;
}
void SharedPreferenceSerializer::AddSharedPrefCmdLineArgs(
mozilla::ipc::GeckoChildProcessHost& procHost,
std::vector<std::string>& aExtraOpts) const {
// Formats a pointer or pointer-sized-integer as a string suitable for passing
// in an arguments list.
auto formatPtrArg = [](auto arg) {
return nsPrintfCString("%zu", uintptr_t(arg));
};
#if defined(XP_WIN)
// Record the handle as to-be-shared, and pass it via a command flag. This
// works because Windows handles are system-wide.
procHost.AddHandleToShare(GetPrefsHandle().get());
procHost.AddHandleToShare(GetPrefMapHandle().get());
aExtraOpts.push_back("-prefsHandle");
aExtraOpts.push_back(formatPtrArg(GetPrefsHandle().get()).get());
aExtraOpts.push_back("-prefMapHandle");
aExtraOpts.push_back(formatPtrArg(GetPrefMapHandle().get()).get());
#else
// In contrast, Unix fds are per-process. So remap the fd to a fixed one that
// will be used in the child.
// XXX: bug 1440207 is about improving how fixed fds are used.
//
// Note: on Android, AddFdToRemap() sets up the fd to be passed via a Parcel,
// and the fixed fd isn't used. However, we still need to mark it for
// remapping so it doesn't get closed in the child.
procHost.AddFdToRemap(GetPrefsHandle().get(), kPrefsFileDescriptor);
procHost.AddFdToRemap(GetPrefMapHandle().get(), kPrefMapFileDescriptor);
#endif
// Pass the lengths via command line flags.
aExtraOpts.push_back("-prefsLen");
aExtraOpts.push_back(formatPtrArg(GetPrefsLength()).get());
aExtraOpts.push_back("-prefMapSize");
aExtraOpts.push_back(formatPtrArg(GetPrefMapSize()).get());
}
#ifdef ANDROID
static int gPrefsFd = -1;
static int gPrefMapFd = -1;
void SetPrefsFd(int aFd) { gPrefsFd = aFd; }
void SetPrefMapFd(int aFd) { gPrefMapFd = aFd; }
#endif
SharedPreferenceDeserializer::SharedPreferenceDeserializer() {
MOZ_COUNT_CTOR(SharedPreferenceDeserializer);
}
SharedPreferenceDeserializer::~SharedPreferenceDeserializer() {
MOZ_COUNT_DTOR(SharedPreferenceDeserializer);
}
bool SharedPreferenceDeserializer::DeserializeFromSharedMemory(
char* aPrefsHandleStr, char* aPrefMapHandleStr, char* aPrefsLenStr,
char* aPrefMapSizeStr) {
#ifdef XP_WIN
MOZ_ASSERT(aPrefsHandleStr && aPrefMapHandleStr, "Can't be null");
#endif
MOZ_ASSERT(aPrefsLenStr && aPrefMapSizeStr, "Can't be null");
// Parses an arg containing a pointer-sized-integer.
auto parseUIntPtrArg = [](char*& aArg) {
// ContentParent uses %zu to print a word-sized unsigned integer. So
// even though strtoull() returns a long long int, it will fit in a
// uintptr_t.
return uintptr_t(strtoull(aArg, &aArg, 10));
};
#ifdef XP_WIN
auto parseHandleArg = [&](char*& aArg) {
return HANDLE(parseUIntPtrArg(aArg));
};
mPrefsHandle = Some(parseHandleArg(aPrefsHandleStr));
if (!aPrefsHandleStr || aPrefsHandleStr[0] != '\0') {
return false;
}
FileDescriptor::UniquePlatformHandle handle(
parseHandleArg(aPrefMapHandleStr));
if (!aPrefMapHandleStr || aPrefMapHandleStr[0] != '\0') {
return false;
}
mPrefMapHandle.emplace(std::move(handle));
#endif
mPrefsLen = Some(parseUIntPtrArg(aPrefsLenStr));
if (!aPrefsLenStr || aPrefsLenStr[0] != '\0') {
return false;
}
mPrefMapSize = Some(parseUIntPtrArg(aPrefMapSizeStr));
if (!aPrefMapSizeStr || aPrefMapSizeStr[0] != '\0') {
return false;
}
#ifdef ANDROID
// Android is different; get the FD via gPrefsFd instead of a fixed fd.
MOZ_RELEASE_ASSERT(gPrefsFd != -1);
mPrefsHandle = Some(base::FileDescriptor(gPrefsFd, /* auto_close */ true));
mPrefMapHandle.emplace(UniqueFileHandle(gPrefMapFd));
#elif XP_UNIX
mPrefsHandle = Some(base::FileDescriptor(kPrefsFileDescriptor,
/* auto_close */ true));
mPrefMapHandle.emplace(UniqueFileHandle(kPrefMapFileDescriptor));
#endif
if (mPrefsHandle.isNothing() || mPrefsLen.isNothing() ||
mPrefMapHandle.isNothing() || mPrefMapSize.isNothing()) {
return false;
}
// Init the shared-memory base preference mapping first, so that only changed
// preferences wind up in heap memory.
Preferences::InitSnapshot(mPrefMapHandle.ref(), *mPrefMapSize);
// Set up early prefs from the shared memory.
if (!mShmem.SetHandle(*mPrefsHandle, /* read_only */ true)) {
NS_ERROR("failed to open shared memory in the child");
return false;
}
if (!mShmem.Map(*mPrefsLen)) {
NS_ERROR("failed to map shared memory in the child");
return false;
}
Preferences::DeserializePreferences(static_cast<char*>(mShmem.memory()),
*mPrefsLen);
return true;
}
const base::SharedMemoryHandle& SharedPreferenceDeserializer::GetPrefsHandle()
const {
MOZ_ASSERT(mPrefsHandle.isSome());
return mPrefsHandle.ref();
}
const FileDescriptor& SharedPreferenceDeserializer::GetPrefMapHandle() const {
MOZ_ASSERT(mPrefMapHandle.isSome());
return mPrefMapHandle.ref();
}
} // namespace ipc
} // namespace mozilla
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