gecko-dev/ipc/glue/ProcessUtils_linux.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=2 autoindent cindent expandtab: */
/* 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 "nsString.h"
#include <sys/prctl.h>
#ifdef MOZ_B2G_LOADER
#include <sys/types.h>
#include <unistd.h>
#include "nsAutoPtr.h"
#include "mozilla/Assertions.h"
#include "mozilla/ipc/PProcLoaderParent.h"
#include "mozilla/ipc/PProcLoaderChild.h"
#include "mozilla/ipc/Transport.h"
#include "mozilla/ipc/FileDescriptorUtils.h"
#include "mozilla/ipc/IOThreadChild.h"
#include "mozilla/dom/ContentProcess.h"
#include "base/file_descriptor_shuffle.h"
#include "mozilla/BackgroundHangMonitor.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/unused.h"
#include "base/process_util.h"
#include "base/eintr_wrapper.h"
#include "mozilla/Preferences.h"
#include "prenv.h"
#include "nsXULAppAPI.h" // export XRE_* functions
#include "nsAppRunner.h"
int content_process_main(int argc, char *argv[]);
typedef mozilla::Vector<int> FdArray;
#endif /* MOZ_B2G_LOADER */
namespace mozilla {
namespace ipc {
void SetThisProcessName(const char *aName)
{
prctl(PR_SET_NAME, (unsigned long)aName, 0uL, 0uL, 0uL);
}
#ifdef MOZ_B2G_LOADER
/**
* How does B2G Loader Work?
*
* <<parent process>> <<child process>>
* ProcLoaderParent -----> ProcLoaderChild
* ^ |
* | load() | content_process_main()
* | V
* ProcLoaderClient Nuwa/plugin-container
* ^
* | ProcLoaderLoad()
* ...
* ContentParent
*
*
* B2G loader includes an IPC protocol PProcLoader for communication
* between client (parent) and server (child). The b2g process is the
* client. It requests the server to load/start the Nuwa process with
* the given arguments, env variables, and file descriptors.
*
* ProcLoaderClientInit() is called by B2G loader to initialize the
* client side, the b2g process. Then the b2g_main() is called to
* start b2g process.
*
* ProcLoaderClientGeckoInit() is called by XRE_main() to create the
* parent actor, |ProcLoaderParent|, of PProcLoader for servicing the
* request to run Nuwa process later once Gecko has been initialized.
*
* ProcLoaderServiceRun() is called by the server process. It starts
* an IOThread and event loop to serve the |ProcLoaderChild|
* implmentation of PProcLoader protocol as the child actor. Once it
* recieves a load() request, it stops the IOThread and event loop,
* then starts running the main function of the content process with
* the given arguments.
*
* NOTE: The server process serves at most one load() request.
*/
using namespace mozilla::dom;
using base::ChildPrivileges;
using base::InjectionArc;
using base::InjectiveMultimap;
using base::ProcessHandle;
using base::ProcessId;
using base::SetCurrentProcessPrivileges;
using base::ShuffleFileDescriptors;
using base::file_handle_mapping_vector;
static bool sProcLoaderClientOnDeinit = false;
static DebugOnly<bool> sProcLoaderClientInitialized = false;
static DebugOnly<bool> sProcLoaderClientGeckoInitialized = false;
static pid_t sProcLoaderPid = 0;
static int sProcLoaderChannelFd = -1;
static PProcLoaderParent *sProcLoaderParent = nullptr;
static MessageLoop *sProcLoaderLoop = nullptr;
static mozilla::UniquePtr<FdArray> sReservedFds;
static void ProcLoaderClientDeinit();
/**
* Some file descriptors, like the child IPC channel FD, must be opened at
* specific numbers. To ensure this, we pre-reserve kReservedFileDescriptors FDs
* starting from kBeginReserveFileDescriptor so that operations like
* __android_log_print() won't take these magic FDs.
*/
static const size_t kReservedFileDescriptors = 5;
static const int kBeginReserveFileDescriptor = STDERR_FILENO + 1;
class ProcLoaderParent : public PProcLoaderParent
{
public:
ProcLoaderParent() {}
virtual ~ProcLoaderParent() {}
virtual void ActorDestroy(ActorDestroyReason aWhy) override;
virtual bool RecvLoadComplete(const int32_t &aPid,
const int32_t &aCookie) override;
};
void
ProcLoaderParent::ActorDestroy(ActorDestroyReason aWhy)
{
if (aWhy == AbnormalShutdown) {
NS_WARNING("ProcLoaderParent is destroyed abnormally.");
}
if (sProcLoaderClientOnDeinit) {
// Get error for closing while the channel is already error.
return;
}
// Destroy self asynchronously.
ProcLoaderClientDeinit();
}
static void
_ProcLoaderParentDestroy(PProcLoaderParent *aLoader)
{
delete aLoader;
sProcLoaderClientOnDeinit = false;
}
bool
ProcLoaderParent::RecvLoadComplete(const int32_t &aPid,
const int32_t &aCookie)
{
return true;
}
static void
CloseFileDescriptors(FdArray& aFds)
{
for (size_t i = 0; i < aFds.length(); i++) {
unused << HANDLE_EINTR(close(aFds[i]));
}
}
/**
* Initialize the client of B2G loader for loader itself.
*
* The initialization of B2G loader are divided into two stages. First
* stage is to collect child info passed from the main program of the
* loader. Second stage is to initialize Gecko according to info from the
* first stage and make the client of loader service ready.
*
* \param aPeerPid is the pid of the child.
* \param aChannelFd is the file descriptor of the socket used for IPC.
*/
static void
ProcLoaderClientInit(pid_t aPeerPid, int aChannelFd)
{
MOZ_ASSERT(!sProcLoaderClientInitialized, "call ProcLoaderClientInit() more than once");
MOZ_ASSERT(aPeerPid != 0 && aChannelFd != -1, "invalid argument");
sProcLoaderPid = aPeerPid;
sProcLoaderChannelFd = aChannelFd;
sProcLoaderClientInitialized = true;
}
/**
* Initialize the client of B2G loader for Gecko.
*/
void
ProcLoaderClientGeckoInit()
{
MOZ_ASSERT(sProcLoaderClientInitialized, "call ProcLoaderClientInit() at first");
MOZ_ASSERT(!sProcLoaderClientGeckoInitialized,
"call ProcLoaderClientGeckoInit() more than once");
if (!Preferences::GetBool("dom.ipc.processPrelaunch.enabled", false)) {
kill(sProcLoaderPid, SIGKILL);
sProcLoaderPid = 0;
close(sProcLoaderChannelFd);
sProcLoaderChannelFd = -1;
return;
}
sProcLoaderClientGeckoInitialized = true;
TransportDescriptor fd;
fd.mFd = base::FileDescriptor(sProcLoaderChannelFd, /*auto_close=*/ false);
sProcLoaderChannelFd = -1;
Transport *transport = OpenDescriptor(fd, Transport::MODE_CLIENT);
sProcLoaderParent = new ProcLoaderParent();
sProcLoaderParent->Open(transport,
sProcLoaderPid,
XRE_GetIOMessageLoop(),
ParentSide);
sProcLoaderLoop = MessageLoop::current();
}
bool ProcLoaderIsInitialized()
{
return sProcLoaderPid != 0;
}
/**
* Shutdown and destroy the client of B2G loader service.
*/
static void
ProcLoaderClientDeinit()
{
MOZ_ASSERT(sProcLoaderClientGeckoInitialized && sProcLoaderClientInitialized);
sProcLoaderClientGeckoInitialized = false;
sProcLoaderClientInitialized = false;
sProcLoaderClientOnDeinit = true;
MOZ_ASSERT(sProcLoaderParent != nullptr);
PProcLoaderParent *procLoaderParent = sProcLoaderParent;
sProcLoaderParent = nullptr;
sProcLoaderLoop = nullptr;
MessageLoop::current()->
PostTask(FROM_HERE,
NewRunnableFunction(&_ProcLoaderParentDestroy,
procLoaderParent));
}
struct AsyncSendLoadData
{
nsTArray<nsCString> mArgv;
nsTArray<nsCString> mEnv;
nsTArray<FDRemap> mFdsremap;
ChildPrivileges mPrivs;
int mCookie;
};
static void
AsyncSendLoad(AsyncSendLoadData *aLoad)
{
PProcLoaderParent *loader = sProcLoaderParent;
DebugOnly<bool> ok =
loader->SendLoad(aLoad->mArgv, aLoad->mEnv, aLoad->mFdsremap,
aLoad->mPrivs, aLoad->mCookie);
MOZ_ASSERT(ok);
delete aLoad;
}
/**
* Request the loader service, the server, to load Nuwa.
*/
bool
ProcLoaderLoad(const char *aArgv[],
const char *aEnvp[],
const file_handle_mapping_vector &aFdsRemap,
const ChildPrivileges aPrivs,
ProcessHandle *aProcessHandle)
{
static int cookie=0;
int i;
if (sProcLoaderParent == nullptr || sProcLoaderPid == 0) {
return false;
}
AsyncSendLoadData *load = new AsyncSendLoadData();
nsTArray<nsCString> &argv = load->mArgv;
for (i = 0; aArgv[i] != nullptr; i++) {
argv.AppendElement(nsCString(aArgv[i]));
}
nsTArray<nsCString> &env = load->mEnv;
for (i = 0; aEnvp[i] != nullptr; i++) {
env.AppendElement(nsCString(aEnvp[i]));
}
nsTArray<FDRemap> &fdsremap = load->mFdsremap;
for (file_handle_mapping_vector::const_iterator fdmap =
aFdsRemap.begin();
fdmap != aFdsRemap.end();
fdmap++) {
fdsremap.AppendElement(FDRemap(FileDescriptor(fdmap->first), fdmap->second));
}
load->mPrivs = aPrivs;
load->mCookie = cookie++;
*aProcessHandle = sProcLoaderPid;
sProcLoaderPid = 0;
sProcLoaderLoop->PostTask(FROM_HERE,
NewRunnableFunction(AsyncSendLoad, load));
return true;
}
class ProcLoaderRunnerBase;
static bool sProcLoaderServing = false;
static ProcLoaderRunnerBase *sProcLoaderDispatchedTask = nullptr;
class ProcLoaderRunnerBase
{
public:
virtual int DoWork() = 0;
virtual ~ProcLoaderRunnerBase() {}
};
class ProcLoaderNoopRunner : public ProcLoaderRunnerBase {
public:
virtual int DoWork();
};
int
ProcLoaderNoopRunner::DoWork() {
return 0;
}
/**
* The runner to load Nuwa at the current process.
*/
class ProcLoaderLoadRunner : public ProcLoaderRunnerBase {
private:
const nsTArray<nsCString> mArgv;
const nsTArray<nsCString> mEnv;
const nsTArray<FDRemap> mFdsRemap;
const ChildPrivileges mPrivs;
void ShuffleFds();
public:
ProcLoaderLoadRunner(const InfallibleTArray<nsCString>& aArgv,
const InfallibleTArray<nsCString>& aEnv,
const InfallibleTArray<FDRemap>& aFdsRemap,
const ChildPrivileges aPrivs)
: mArgv(aArgv)
, mEnv(aEnv)
, mFdsRemap(aFdsRemap)
, mPrivs(aPrivs) {}
int DoWork();
};
void
ProcLoaderLoadRunner::ShuffleFds()
{
unsigned int i;
MOZ_ASSERT(mFdsRemap.Length() <= kReservedFileDescriptors);
InjectiveMultimap fd_shuffle;
fd_shuffle.reserve(mFdsRemap.Length());
for (i = 0; i < mFdsRemap.Length(); i++) {
const FDRemap *map = &mFdsRemap[i];
int fd = map->fd().PlatformHandle();
int tofd = map->mapto();
// The FD that is dup2()'d from needs to be closed after shuffling.
fd_shuffle.push_back(InjectionArc(fd, tofd, /*in_close=*/true));
// Erase from sReservedFds we will use.
for (int* toErase = sReservedFds->begin();
toErase < sReservedFds->end();
toErase++) {
if (tofd == *toErase) {
sReservedFds->erase(toErase);
break;
}
}
}
DebugOnly<bool> ok = ShuffleFileDescriptors(&fd_shuffle);
// Close the FDs that are reserved but not used after
// ShuffleFileDescriptors().
MOZ_ASSERT(sReservedFds);
CloseFileDescriptors(*sReservedFds);
sReservedFds = nullptr;
// Note that we don'e call ::base::CloseSuperfluousFds() here, assuming that
// The file descriptor inherited from the parent are also necessary for us.
}
int
ProcLoaderLoadRunner::DoWork()
{
unsigned int i;
ShuffleFds();
unsigned int argc = mArgv.Length();
char **argv = new char *[argc + 1];
for (i = 0; i < argc; i++) {
argv[i] = ::strdup(mArgv[i].get());
}
argv[argc] = nullptr;
unsigned int envc = mEnv.Length();
for (i = 0; i < envc; i++) {
PR_SetEnv(mEnv[i].get());
}
SetCurrentProcessPrivileges(mPrivs);
// Start Nuwa (main function)
int ret = content_process_main(argc, argv);
for (i = 0; i < argc; i++) {
free(argv[i]);
}
delete[] argv;
return ret;
}
class ProcLoaderChild : public PProcLoaderChild
{
pid_t mPeerPid;
public:
ProcLoaderChild(pid_t aPeerPid) : mPeerPid(aPeerPid) {}
virtual void ActorDestroy(ActorDestroyReason aWhy) override;
virtual bool RecvLoad(InfallibleTArray<nsCString>&& aArgv,
InfallibleTArray<nsCString>&& aEnv,
InfallibleTArray<FDRemap>&& aFdsremap,
const uint32_t& aPrivs,
const int32_t& aCookie);
virtual void OnChannelError();
};
void
ProcLoaderChild::ActorDestroy(ActorDestroyReason aWhy)
{
}
static void
_ProcLoaderChildDestroy(ProcLoaderChild *aChild)
{
aChild->Close();
delete aChild;
MessageLoop::current()->Quit();
}
bool
ProcLoaderChild::RecvLoad(InfallibleTArray<nsCString>&& aArgv,
InfallibleTArray<nsCString>&& aEnv,
InfallibleTArray<FDRemap>&& aFdsRemap,
const uint32_t& aPrivs,
const int32_t& aCookie) {
if (!sProcLoaderServing) {
return true;
}
sProcLoaderServing = false;
MOZ_ASSERT(sProcLoaderDispatchedTask == nullptr);
ChildPrivileges privs = static_cast<ChildPrivileges>(aPrivs);
sProcLoaderDispatchedTask =
new ProcLoaderLoadRunner(aArgv, aEnv, aFdsRemap, privs);
SendLoadComplete(mPeerPid, aCookie);
MessageLoop::current()->PostTask(FROM_HERE,
NewRunnableFunction(_ProcLoaderChildDestroy,
this));
return true;
}
void
ProcLoaderChild::OnChannelError()
{
if (!sProcLoaderServing) {
return;
}
sProcLoaderServing = false;
PProcLoaderChild::OnChannelError();
MOZ_ASSERT(sProcLoaderDispatchedTask == nullptr);
sProcLoaderDispatchedTask = new ProcLoaderNoopRunner();
MessageLoop::current()->PostTask(FROM_HERE,
NewRunnableFunction(_ProcLoaderChildDestroy,
this));
}
/**
* A helper class which calls NS_LogInit/NS_LogTerm in its scope.
*/
class ScopedLogging
{
public:
ScopedLogging() { NS_LogInit(); }
~ScopedLogging() { NS_LogTerm(); }
};
/**
* Run service of ProcLoader.
*
* \param aPeerPid is the pid of the parent.
* \param aFd is the file descriptor of the socket for IPC.
*
* See the comment near the head of this file.
*/
static int
ProcLoaderServiceRun(pid_t aPeerPid, int aFd,
int aArgc, const char *aArgv[],
FdArray& aReservedFds)
{
// Make a copy of aReservedFds. It will be used when we dup() the magic file
// descriptors when ProcLoaderChild::RecvLoad() runs.
sReservedFds = MakeUnique<FdArray>(mozilla::Move(aReservedFds));
ScopedLogging logging;
char **_argv;
_argv = new char *[aArgc + 1];
for (int i = 0; i < aArgc; i++) {
_argv[i] = ::strdup(aArgv[i]);
MOZ_ASSERT(_argv[i] != nullptr);
}
_argv[aArgc] = nullptr;
gArgv = _argv;
gArgc = aArgc;
{
nsresult rv = XRE_InitCommandLine(aArgc, _argv);
if (NS_FAILED(rv)) {
MOZ_CRASH();
}
TransportDescriptor fd;
fd.mFd = base::FileDescriptor(aFd, /*auto_close =*/false);
MOZ_ASSERT(!sProcLoaderServing);
MessageLoop loop;
nsAutoPtr<ContentProcess> process;
process = new ContentProcess(aPeerPid);
ChildThread *iothread = process->child_thread();
Transport *transport = OpenDescriptor(fd, Transport::MODE_CLIENT);
ProcLoaderChild *loaderChild = new ProcLoaderChild(aPeerPid);
// Pass a message loop to initialize (connect) the channel
// (connection).
loaderChild->Open(transport, aPeerPid, iothread->message_loop());
BackgroundHangMonitor::Prohibit();
sProcLoaderServing = true;
loop.Run();
BackgroundHangMonitor::Allow();
XRE_DeinitCommandLine();
}
MOZ_ASSERT(sProcLoaderDispatchedTask != nullptr);
ProcLoaderRunnerBase *task = sProcLoaderDispatchedTask;
sProcLoaderDispatchedTask = nullptr;
int ret = task->DoWork();
delete task;
for (int i = 0; i < aArgc; i++) {
free(_argv[i]);
}
delete[] _argv;
return ret;
}
#endif /* MOZ_B2G_LOADER */
} // namespace ipc
} // namespace mozilla
#ifdef MOZ_B2G_LOADER
void
XRE_ProcLoaderClientInit(pid_t aPeerPid, int aChannelFd, FdArray& aReservedFds)
{
// We already performed fork(). It's safe to free the "danger zone" of file
// descriptors .
mozilla::ipc::CloseFileDescriptors(aReservedFds);
mozilla::ipc::ProcLoaderClientInit(aPeerPid, aChannelFd);
}
int
XRE_ProcLoaderServiceRun(pid_t aPeerPid, int aFd,
int aArgc, const char *aArgv[],
FdArray& aReservedFds)
{
return mozilla::ipc::ProcLoaderServiceRun(aPeerPid, aFd,
aArgc, aArgv,
aReservedFds);
}
#endif /* MOZ_B2G_LOADER */