/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* 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 <map>
#include <mach/vm_map.h>
#include <mach/mach_port.h>
#if defined(XP_IOS)
#include <mach/vm_map.h>
#define mach_vm_address_t vm_address_t
#define mach_vm_allocate vm_allocate
#define mach_vm_deallocate vm_deallocate
#define mach_vm_map vm_map
#define mach_vm_read vm_read
#define mach_vm_region_recurse vm_region_recurse_64
#define mach_vm_size_t vm_size_t
#else
#include <mach/mach_vm.h>
#endif
#include <pthread.h>
#include <unistd.h>
#include "SharedMemoryBasic.h"
#include "chrome/common/mach_ipc_mac.h"
#include "mozilla/IntegerPrintfMacros.h"
#include "mozilla/Printf.h"
#include "mozilla/StaticMutex.h"
#ifdef DEBUG
#define LOG_ERROR(str, args...) \
PR_BEGIN_MACRO \
mozilla::SmprintfPointer msg = mozilla::Smprintf(str, ## args); \
NS_WARNING(msg.get()); \
PR_END_MACRO
#else
#define LOG_ERROR(str, args...) do { /* nothing */ } while(0)
#endif
#define CHECK_MACH_ERROR(kr, msg) \
PR_BEGIN_MACRO \
if (kr != KERN_SUCCESS) { \
LOG_ERROR("%s %s (%x)\n", msg, mach_error_string(kr), kr); \
return false; \
} \
PR_END_MACRO
/*
* This code is responsible for sharing memory between processes. Memory can be
* shared between parent and child or between two children. Each memory region is
* referenced via a Mach port. Mach ports are also used for messaging when
* sharing a memory region.
*
* When the parent starts a child, it starts a thread whose only purpose is to
* communicate with the child about shared memory. Once the child has started,
* it starts a similar thread for communicating with the parent. Each side can
* communicate with the thread on the other side via Mach ports. When either
* side wants to share memory with the other, it sends a Mach message to the
* other side. Attached to the message is the port that references the shared
* memory region. When the other side receives the message, it automatically
* gets access to the region. It sends a reply (also via a Mach port) so that
* the originating side can continue.
*
* The two sides communicate using four ports. Two ports are used when the
* parent shares memory with the child. The other two are used when the child
* shares memory with the parent. One of these two ports is used for sending the
* "share" message and the other is used for the reply.
*
* If a child wants to share memory with another child, it sends a "GetPorts"
* message to the parent. The parent forwards this GetPorts message to the
* target child. The message includes some ports so that the children can talk
* directly. Both children start up a thread to communicate with the other child,
* similar to the way parent and child communicate. In the future, when these
* two children want to communicate, they re-use the channels that were created.
*
* When a child shuts down, the parent notifies all other children. Those
* children then have the opportunity to shut down any threads they might have
* been using to communicate directly with that child.
*/
namespace mozilla {
namespace ipc {
struct MemoryPorts {
MachPortSender* mSender;
ReceivePort* mReceiver;
MemoryPorts() = default;
MemoryPorts(MachPortSender* sender, ReceivePort* receiver)
: mSender(sender), mReceiver(receiver) {}
};
// Protects gMemoryCommPorts and gThreads.
static StaticMutex gMutex;
static std::map<pid_t, MemoryPorts> gMemoryCommPorts;
enum {
kGetPortsMsg = 1,
kSharePortsMsg,
kReturnIdMsg,
kReturnPortsMsg,
kShutdownMsg,
kCleanupMsg,
};
const int kTimeout = 1000;
const int kLongTimeout = 60 * kTimeout;
pid_t gParentPid = 0;
struct PIDPair {
pid_t mRequester;
pid_t mRequested;
PIDPair(pid_t requester, pid_t requested)
: mRequester(requester), mRequested(requested) {}
};
struct ListeningThread {
pthread_t mThread;
MemoryPorts* mPorts;
ListeningThread() = default;
ListeningThread(pthread_t thread, MemoryPorts* ports)
: mThread(thread), mPorts(ports) {}
};
struct SharePortsReply {
uint64_t serial;
mach_port_t port;
};
std::map<pid_t, ListeningThread> gThreads;
static void *
PortServerThread(void *argument);
static void
SetupMachMemory(pid_t pid,
ReceivePort* listen_port,
MachPortSender* listen_port_ack,
MachPortSender* send_port,
ReceivePort* send_port_ack,
bool pidIsParent)
{
if (pidIsParent) {
gParentPid = pid;
}
auto* listen_ports = new MemoryPorts(listen_port_ack, listen_port);
pthread_t thread;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
int err = pthread_create(&thread, &attr, PortServerThread, listen_ports);
if (err) {
LOG_ERROR("pthread_create failed with %x\n", err);
return;
}
gMutex.AssertCurrentThreadOwns();
gThreads[pid] = ListeningThread(thread, listen_ports);
gMemoryCommPorts[pid] = MemoryPorts(send_port, send_port_ack);
}
// Send two communication ports to another process along with the pid of the process that is
// listening on them.
bool
SendPortsMessage(MachPortSender* sender,
mach_port_t ports_in_receiver,
mach_port_t ports_out_receiver,
PIDPair pid_pair)
{
MachSendMessage getPortsMsg(kGetPortsMsg);
if (!getPortsMsg.AddDescriptor(MachMsgPortDescriptor(ports_in_receiver))) {
LOG_ERROR("Adding descriptor to message failed");
return false;
}
if (!getPortsMsg.AddDescriptor(MachMsgPortDescriptor(ports_out_receiver))) {
LOG_ERROR("Adding descriptor to message failed");
return false;
}
getPortsMsg.SetData(&pid_pair, sizeof(PIDPair));
kern_return_t err = sender->SendMessage(getPortsMsg, kTimeout);
if (KERN_SUCCESS != err) {
LOG_ERROR("Error sending get ports message %s (%x)\n", mach_error_string(err), err);
return false;
}
return true;
}
// Receive two communication ports from another process
bool
RecvPortsMessage(ReceivePort* receiver, mach_port_t* ports_in_sender, mach_port_t* ports_out_sender)
{
MachReceiveMessage rcvPortsMsg;
kern_return_t err = receiver->WaitForMessage(&rcvPortsMsg, kTimeout);
if (KERN_SUCCESS != err) {
LOG_ERROR("Error receiving get ports message %s (%x)\n", mach_error_string(err), err);
}
if (rcvPortsMsg.GetTranslatedPort(0) == MACH_PORT_NULL) {
LOG_ERROR("GetTranslatedPort(0) failed");
return false;
}
*ports_in_sender = rcvPortsMsg.GetTranslatedPort(0);
if (rcvPortsMsg.GetTranslatedPort(1) == MACH_PORT_NULL) {
LOG_ERROR("GetTranslatedPort(1) failed");
return false;
}
*ports_out_sender = rcvPortsMsg.GetTranslatedPort(1);
return true;
}
// Send two communication ports to another process and receive two back
bool
RequestPorts(const MemoryPorts& request_ports,
mach_port_t ports_in_receiver,
mach_port_t* ports_in_sender,
mach_port_t* ports_out_sender,
mach_port_t ports_out_receiver,
PIDPair pid_pair)
{
if (!SendPortsMessage(request_ports.mSender, ports_in_receiver, ports_out_receiver, pid_pair)) {
return false;
}
return RecvPortsMessage(request_ports.mReceiver, ports_in_sender, ports_out_sender);
}
MemoryPorts*
GetMemoryPortsForPid(pid_t pid)
{
gMutex.AssertCurrentThreadOwns();
if (gMemoryCommPorts.find(pid) == gMemoryCommPorts.end()) {
// We don't have the ports open to communicate with that pid, so we're going to
// ask our parent process over IPC to set them up for us.
if (gParentPid == 0) {
// If we're the top level parent process, we have no parent to ask.
LOG_ERROR("request for ports for pid %d, but we're the chrome process\n", pid);
return nullptr;
}
const MemoryPorts& parent = gMemoryCommPorts[gParentPid];
// Create two receiving ports in this process to send to the parent. One will be used for
// for listening for incoming memory to be shared, the other for getting the Handle of
// memory we share to the other process.
auto* ports_in_receiver = new ReceivePort();
auto* ports_out_receiver = new ReceivePort();
mach_port_t raw_ports_in_sender, raw_ports_out_sender;
if (!RequestPorts(parent,
ports_in_receiver->GetPort(),
&raw_ports_in_sender,
&raw_ports_out_sender,
ports_out_receiver->GetPort(),
PIDPair(getpid(), pid))) {
LOG_ERROR("failed to request ports\n");
return nullptr;
}
// Our parent process sent us two ports, one is for sending new memory to, the other
// is for replying with the Handle when we receive new memory.
auto* ports_in_sender = new MachPortSender(raw_ports_in_sender);
auto* ports_out_sender = new MachPortSender(raw_ports_out_sender);
SetupMachMemory(pid,
ports_in_receiver,
ports_in_sender,
ports_out_sender,
ports_out_receiver,
false);
MOZ_ASSERT(gMemoryCommPorts.find(pid) != gMemoryCommPorts.end());
}
return &gMemoryCommPorts.at(pid);
}
// We just received a port representing a region of shared memory, reply to
// the process that set it with the mach_port_t that represents it in this process.
// That will be the Handle to be shared over normal IPC
void
HandleSharePortsMessage(MachReceiveMessage* rmsg, MemoryPorts* ports)
{
mach_port_t port = rmsg->GetTranslatedPort(0);
uint64_t* serial = reinterpret_cast<uint64_t*>(rmsg->GetData());
MachSendMessage msg(kReturnIdMsg);
// Construct the reply message, echoing the serial, and adding the port
SharePortsReply replydata;
replydata.port = port;
replydata.serial = *serial;
msg.SetData(&replydata, sizeof(SharePortsReply));
kern_return_t err = ports->mSender->SendMessage(msg, kTimeout);
if (KERN_SUCCESS != err) {
LOG_ERROR("SendMessage failed 0x%x %s\n", err, mach_error_string(err));
}
}
// We were asked by another process to get communications ports to some process. Return
// those ports via an IPC message.
bool
SendReturnPortsMsg(MachPortSender* sender,
mach_port_t raw_ports_in_sender,
mach_port_t raw_ports_out_sender)
{
MachSendMessage getPortsMsg(kReturnPortsMsg);
if (!getPortsMsg.AddDescriptor(MachMsgPortDescriptor(raw_ports_in_sender))) {
LOG_ERROR("Adding descriptor to message failed");
return false;
}
if (!getPortsMsg.AddDescriptor(MachMsgPortDescriptor(raw_ports_out_sender))) {
LOG_ERROR("Adding descriptor to message failed");
return false;
}
kern_return_t err = sender->SendMessage(getPortsMsg, kTimeout);
if (KERN_SUCCESS != err) {
LOG_ERROR("Error sending get ports message %s (%x)\n", mach_error_string(err), err);
return false;
}
return true;
}
// We were asked for communcations ports to a process that isn't us. Assuming that process
// is one of our children, forward that request on.
void
ForwardGetPortsMessage(MachReceiveMessage* rmsg, MemoryPorts* ports, PIDPair* pid_pair)
{
if (rmsg->GetTranslatedPort(0) == MACH_PORT_NULL) {
LOG_ERROR("GetTranslatedPort(0) failed");
return;
}
if (rmsg->GetTranslatedPort(1) == MACH_PORT_NULL) {
LOG_ERROR("GetTranslatedPort(1) failed");
return;
}
mach_port_t raw_ports_in_sender, raw_ports_out_sender;
MemoryPorts* requestedPorts = GetMemoryPortsForPid(pid_pair->mRequested);
if (!requestedPorts) {
LOG_ERROR("failed to find port for process\n");
return;
}
if (!RequestPorts(*requestedPorts, rmsg->GetTranslatedPort(0), &raw_ports_in_sender,
&raw_ports_out_sender, rmsg->GetTranslatedPort(1), *pid_pair)) {
LOG_ERROR("failed to request ports\n");
return;
}
SendReturnPortsMsg(ports->mSender, raw_ports_in_sender, raw_ports_out_sender);
}
// We receieved a message asking us to get communications ports for another process
void
HandleGetPortsMessage(MachReceiveMessage* rmsg, MemoryPorts* ports)
{
PIDPair* pid_pair;
if (rmsg->GetDataLength() != sizeof(PIDPair)) {
LOG_ERROR("Improperly formatted message\n");
return;
}
pid_pair = reinterpret_cast<PIDPair*>(rmsg->GetData());
if (pid_pair->mRequested != getpid()) {
// This request is for ports to a process that isn't us, forward it to that process
ForwardGetPortsMessage(rmsg, ports, pid_pair);
} else {
if (rmsg->GetTranslatedPort(0) == MACH_PORT_NULL) {
LOG_ERROR("GetTranslatedPort(0) failed");
return;
}
if (rmsg->GetTranslatedPort(1) == MACH_PORT_NULL) {
LOG_ERROR("GetTranslatedPort(1) failed");
return;
}
auto* ports_in_sender = new MachPortSender(rmsg->GetTranslatedPort(0));
auto* ports_out_sender = new MachPortSender(rmsg->GetTranslatedPort(1));
auto* ports_in_receiver = new ReceivePort();
auto* ports_out_receiver = new ReceivePort();
if (SendReturnPortsMsg(ports->mSender, ports_in_receiver->GetPort(), ports_out_receiver->GetPort())) {
SetupMachMemory(pid_pair->mRequester,
ports_out_receiver,
ports_out_sender,
ports_in_sender,
ports_in_receiver,
false);
}
}
}
static void *
PortServerThread(void *argument)
{
MemoryPorts* ports = static_cast<MemoryPorts*>(argument);
MachReceiveMessage child_message;
while (true) {
MachReceiveMessage rmsg;
kern_return_t err = ports->mReceiver->WaitForMessage(&rmsg, MACH_MSG_TIMEOUT_NONE);
if (err != KERN_SUCCESS) {
LOG_ERROR("Wait for message failed 0x%x %s\n", err, mach_error_string(err));
continue;
}
if (rmsg.GetMessageID() == kShutdownMsg) {
delete ports->mSender;
delete ports->mReceiver;
delete ports;
return nullptr;
}
StaticMutexAutoLock smal(gMutex);
switch (rmsg.GetMessageID()) {
case kSharePortsMsg:
HandleSharePortsMessage(&rmsg, ports);
break;
case kGetPortsMsg:
HandleGetPortsMessage(&rmsg, ports);
break;
case kCleanupMsg:
if (gParentPid == 0) {
LOG_ERROR("Cleanup message not valid for parent process");
continue;
}
pid_t* pid;
if (rmsg.GetDataLength() != sizeof(pid_t)) {
LOG_ERROR("Improperly formatted message\n");
continue;
}
pid = reinterpret_cast<pid_t*>(rmsg.GetData());
SharedMemoryBasic::CleanupForPid(*pid);
break;
default:
LOG_ERROR("Unknown message\n");
}
}
}
void
SharedMemoryBasic::SetupMachMemory(pid_t pid,
ReceivePort* listen_port,
MachPortSender* listen_port_ack,
MachPortSender* send_port,
ReceivePort* send_port_ack,
bool pidIsParent)
{
StaticMutexAutoLock smal(gMutex);
mozilla::ipc::SetupMachMemory(pid, listen_port, listen_port_ack, send_port, send_port_ack, pidIsParent);
}
void
SharedMemoryBasic::Shutdown()
{
StaticMutexAutoLock smal(gMutex);
for (auto& thread : gThreads) {
MachSendMessage shutdownMsg(kShutdownMsg);
thread.second.mPorts->mReceiver->SendMessageToSelf(shutdownMsg, kTimeout);
}
gThreads.clear();
for (auto& memoryCommPort : gMemoryCommPorts) {
delete memoryCommPort.second.mSender;
delete memoryCommPort.second.mReceiver;
}
gMemoryCommPorts.clear();
}
void
SharedMemoryBasic::CleanupForPid(pid_t pid)
{
if (gThreads.find(pid) == gThreads.end()) {
return;
}
const ListeningThread& listeningThread = gThreads[pid];
MachSendMessage shutdownMsg(kShutdownMsg);
kern_return_t ret = listeningThread.mPorts->mReceiver->SendMessageToSelf(shutdownMsg, kTimeout);
if (ret != KERN_SUCCESS) {
LOG_ERROR("sending shutdown msg failed %s %x\n", mach_error_string(ret), ret);
}
gThreads.erase(pid);
if (gParentPid == 0) {
// We're the parent. Broadcast the cleanup message to everyone else.
for (auto& memoryCommPort : gMemoryCommPorts) {
MachSendMessage msg(kCleanupMsg);
msg.SetData(&pid, sizeof(pid));
// We don't really care if this fails, we could be trying to send to an already shut down proc
memoryCommPort.second.mSender->SendMessage(msg, kTimeout);
}
}
MemoryPorts& ports = gMemoryCommPorts[pid];
delete ports.mSender;
delete ports.mReceiver;
gMemoryCommPorts.erase(pid);
}
SharedMemoryBasic::SharedMemoryBasic()
: mPort(MACH_PORT_NULL)
, mMemory(nullptr)
, mOpenRights(RightsReadWrite)
{
}
SharedMemoryBasic::~SharedMemoryBasic()
{
Unmap();
CloseHandle();
}
bool
SharedMemoryBasic::SetHandle(const Handle& aHandle, OpenRights aRights)
{
MOZ_ASSERT(mPort == MACH_PORT_NULL, "already initialized");
mPort = aHandle;
mOpenRights = aRights;
return true;
}
static inline void*
toPointer(mach_vm_address_t address)
{
return reinterpret_cast<void*>(static_cast<uintptr_t>(address));
}
static inline mach_vm_address_t
toVMAddress(void* pointer)
{
return static_cast<mach_vm_address_t>(reinterpret_cast<uintptr_t>(pointer));
}
bool
SharedMemoryBasic::Create(size_t size)
{
MOZ_ASSERT(mPort == MACH_PORT_NULL, "already initialized");
mach_vm_address_t address;
kern_return_t kr = mach_vm_allocate(mach_task_self(), &address, round_page(size), VM_FLAGS_ANYWHERE);
if (kr != KERN_SUCCESS) {
LOG_ERROR("Failed to allocate mach_vm_allocate shared memory (%zu bytes). %s (%x)\n",
size, mach_error_string(kr), kr);
return false;
}
memory_object_size_t memoryObjectSize = round_page(size);
kr = mach_make_memory_entry_64(mach_task_self(),
&memoryObjectSize,
address,
VM_PROT_DEFAULT,
&mPort,
MACH_PORT_NULL);
if (kr != KERN_SUCCESS || memoryObjectSize < round_page(size)) {
LOG_ERROR("Failed to make memory entry (%zu bytes). %s (%x)\n",
size, mach_error_string(kr), kr);
CloseHandle();
mach_vm_deallocate(mach_task_self(), address, round_page(size));
return false;
}
mMemory = toPointer(address);
Mapped(size);
return true;
}
bool
SharedMemoryBasic::Map(size_t size)
{
if (mMemory) {
return true;
}
if (MACH_PORT_NULL == mPort) {
return false;
}
kern_return_t kr;
mach_vm_address_t address = 0;
vm_prot_t vmProtection = VM_PROT_READ;
if (mOpenRights == RightsReadWrite) {
vmProtection |= VM_PROT_WRITE;
}
kr = mach_vm_map(mach_task_self(), &address, round_page(size), 0, VM_FLAGS_ANYWHERE,
mPort, 0, false, vmProtection, vmProtection, VM_INHERIT_NONE);
if (kr != KERN_SUCCESS) {
LOG_ERROR("Failed to map shared memory (%zu bytes) into %x, port %x. %s (%x)\n",
size, mach_task_self(), mPort, mach_error_string(kr), kr);
return false;
}
mMemory = toPointer(address);
Mapped(size);
return true;
}
bool
SharedMemoryBasic::ShareToProcess(base::ProcessId pid,
Handle* aNewHandle)
{
if (pid == getpid()) {
*aNewHandle = mPort;
return mach_port_mod_refs(mach_task_self(), *aNewHandle, MACH_PORT_RIGHT_SEND, 1) == KERN_SUCCESS;
}
StaticMutexAutoLock smal(gMutex);
// Serially number the messages, to check whether
// the reply we get was meant for us.
static uint64_t serial = 0;
uint64_t my_serial = serial;
serial++;
MemoryPorts* ports = GetMemoryPortsForPid(pid);
if (!ports) {
LOG_ERROR("Unable to get ports for process.\n");
return false;
}
MachSendMessage smsg(kSharePortsMsg);
smsg.AddDescriptor(MachMsgPortDescriptor(mPort, MACH_MSG_TYPE_COPY_SEND));
smsg.SetData(&my_serial, sizeof(uint64_t));
kern_return_t err = ports->mSender->SendMessage(smsg, kTimeout);
if (err != KERN_SUCCESS) {
LOG_ERROR("sending port failed %s %x\n", mach_error_string(err), err);
return false;
}
MachReceiveMessage msg;
err = ports->mReceiver->WaitForMessage(&msg, kTimeout);
if (err != KERN_SUCCESS) {
LOG_ERROR("short timeout didn't get an id %s %x\n", mach_error_string(err), err);
err = ports->mReceiver->WaitForMessage(&msg, kLongTimeout);
if (err != KERN_SUCCESS) {
LOG_ERROR("long timeout didn't get an id %s %x\n", mach_error_string(err), err);
return false;
}
}
if (msg.GetDataLength() != sizeof(SharePortsReply)) {
LOG_ERROR("Improperly formatted reply\n");
return false;
}
SharePortsReply* msg_data = reinterpret_cast<SharePortsReply*>(msg.GetData());
mach_port_t id = msg_data->port;
uint64_t serial_check = msg_data->serial;
if (serial_check != my_serial) {
LOG_ERROR("Serials do not match up: %" PRIu64 " vs %" PRIu64 "", serial_check, my_serial);
return false;
}
*aNewHandle = id;
return true;
}
void
SharedMemoryBasic::Unmap()
{
if (!mMemory) {
return;
}
vm_address_t address = toVMAddress(mMemory);
kern_return_t kr = vm_deallocate(mach_task_self(), address, round_page(mMappedSize));
if (kr != KERN_SUCCESS) {
LOG_ERROR("Failed to deallocate shared memory. %s (%x)\n", mach_error_string(kr), kr);
return;
}
mMemory = nullptr;
}
void
SharedMemoryBasic::CloseHandle()
{
if (mPort != MACH_PORT_NULL) {
mach_port_deallocate(mach_task_self(), mPort);
mPort = MACH_PORT_NULL;
mOpenRights = RightsReadWrite;
}
}
bool
SharedMemoryBasic::IsHandleValid(const Handle& aHandle) const
{
return aHandle > 0;
}
} // namespace ipc
} // namespace mozilla