/*
* Copyright (C) 2005 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "ProcessState"
#include <binder/ProcessState.h>
#include <binder/BpBinder.h>
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <cutils/atomic.h>
#include <utils/Log.h>
#include <utils/String8.h>
#include <utils/String8.h>
#include <utils/threads.h>
#include <private/binder/binder_module.h>
#include <private/binder/Static.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#define BINDER_VM_SIZE ((1 * 1024 * 1024) - sysconf(_SC_PAGE_SIZE) * 2)
#define DEFAULT_MAX_BINDER_THREADS 15
#ifdef __ANDROID_VNDK__
const char* kDefaultDriver = "/dev/vndbinder";
#else
const char* kDefaultDriver = "/dev/binder";
#endif
// -------------------------------------------------------------------------
namespace android {
class PoolThread : public Thread
{
public:
explicit PoolThread(bool isMain)
: mIsMain(isMain)
{
}
protected:
virtual bool threadLoop()
{
IPCThreadState::self()->joinThreadPool(mIsMain);
return false;
}
const bool mIsMain;
};
sp<ProcessState> ProcessState::self()
{
Mutex::Autolock _l(gProcessMutex);
if (gProcess != nullptr) {
return gProcess;
}
gProcess = new ProcessState(kDefaultDriver);
return gProcess;
}
sp<ProcessState> ProcessState::initWithDriver(const char* driver)
{
Mutex::Autolock _l(gProcessMutex);
if (gProcess != nullptr) {
// Allow for initWithDriver to be called repeatedly with the same
// driver.
if (!strcmp(gProcess->getDriverName().c_str(), driver)) {
return gProcess;
}
LOG_ALWAYS_FATAL("ProcessState was already initialized.");
}
if (access(driver, R_OK) == -1) {
ALOGE("Binder driver %s is unavailable. Using /dev/binder instead.", driver);
driver = "/dev/binder";
}
gProcess = new ProcessState(driver);
return gProcess;
}
sp<ProcessState> ProcessState::selfOrNull()
{
Mutex::Autolock _l(gProcessMutex);
return gProcess;
}
void ProcessState::setContextObject(const sp<IBinder>& object)
{
setContextObject(object, String16("default"));
}
sp<IBinder> ProcessState::getContextObject(const sp<IBinder>& /*caller*/)
{
return getStrongProxyForHandle(0);
}
void ProcessState::setContextObject(const sp<IBinder>& object, const String16& name)
{
AutoMutex _l(mLock);
mContexts.add(name, object);
}
sp<IBinder> ProcessState::getContextObject(const String16& name, const sp<IBinder>& caller)
{
mLock.lock();
sp<IBinder> object(
mContexts.indexOfKey(name) >= 0 ? mContexts.valueFor(name) : nullptr);
mLock.unlock();
//printf("Getting context object %s for %p\n", String8(name).string(), caller.get());
if (object != nullptr) return object;
// Don't attempt to retrieve contexts if we manage them
if (mManagesContexts) {
ALOGE("getContextObject(%s) failed, but we manage the contexts!\n",
String8(name).string());
return nullptr;
}
IPCThreadState* ipc = IPCThreadState::self();
{
Parcel data, reply;
// no interface token on this magic transaction
data.writeString16(name);
data.writeStrongBinder(caller);
status_t result = ipc->transact(0 /*magic*/, 0, data, &reply, 0);
if (result == NO_ERROR) {
object = reply.readStrongBinder();
}
}
ipc->flushCommands();
if (object != nullptr) setContextObject(object, name);
return object;
}
void ProcessState::startThreadPool()
{
AutoMutex _l(mLock);
if (!mThreadPoolStarted) {
mThreadPoolStarted = true;
spawnPooledThread(true);
}
}
bool ProcessState::isContextManager(void) const
{
return mManagesContexts;
}
bool ProcessState::becomeContextManager(context_check_func checkFunc, void* userData)
{
if (!mManagesContexts) {
AutoMutex _l(mLock);
mBinderContextCheckFunc = checkFunc;
mBinderContextUserData = userData;
flat_binder_object obj {
.flags = FLAT_BINDER_FLAG_TXN_SECURITY_CTX,
};
status_t result = ioctl(mDriverFD, BINDER_SET_CONTEXT_MGR_EXT, &obj);
// fallback to original method
if (result != 0) {
android_errorWriteLog(0x534e4554, "121035042");
int dummy = 0;
result = ioctl(mDriverFD, BINDER_SET_CONTEXT_MGR, &dummy);
}
if (result == 0) {
mManagesContexts = true;
} else if (result == -1) {
mBinderContextCheckFunc = nullptr;
mBinderContextUserData = nullptr;
ALOGE("Binder ioctl to become context manager failed: %s\n", strerror(errno));
}
}
return mManagesContexts;
}
// Get references to userspace objects held by the kernel binder driver
// Writes up to count elements into buf, and returns the total number
// of references the kernel has, which may be larger than count.
// buf may be NULL if count is 0. The pointers returned by this method
// should only be used for debugging and not dereferenced, they may
// already be invalid.
ssize_t ProcessState::getKernelReferences(size_t buf_count, uintptr_t* buf)
{
binder_node_debug_info info = {};
uintptr_t* end = buf ? buf + buf_count : nullptr;
size_t count = 0;
do {
status_t result = ioctl(mDriverFD, BINDER_GET_NODE_DEBUG_INFO, &info);
if (result < 0) {
return -1;
}
if (info.ptr != 0) {
if (buf && buf < end)
*buf++ = info.ptr;
count++;
if (buf && buf < end)
*buf++ = info.cookie;
count++;
}
} while (info.ptr != 0);
return count;
}
void ProcessState::setCallRestriction(CallRestriction restriction) {
LOG_ALWAYS_FATAL_IF(IPCThreadState::selfOrNull(), "Call restrictions must be set before the threadpool is started.");
mCallRestriction = restriction;
}
ProcessState::handle_entry* ProcessState::lookupHandleLocked(int32_t handle)
{
const size_t N=mHandleToObject.size();
if (N <= (size_t)handle) {
handle_entry e;
e.binder = nullptr;
e.refs = nullptr;
status_t err = mHandleToObject.insertAt(e, N, handle+1-N);
if (err < NO_ERROR) return nullptr;
}
return &mHandleToObject.editItemAt(handle);
}
sp<IBinder> ProcessState::getStrongProxyForHandle(int32_t handle)
{
sp<IBinder> result;
AutoMutex _l(mLock);
handle_entry* e = lookupHandleLocked(handle);
if (e != nullptr) {
// We need to create a new BpBinder if there isn't currently one, OR we
// are unable to acquire a weak reference on this current one. See comment
// in getWeakProxyForHandle() for more info about this.
IBinder* b = e->binder;
if (b == nullptr || !e->refs->attemptIncWeak(this)) {
if (handle == 0) {
// Special case for context manager...
// The context manager is the only object for which we create
// a BpBinder proxy without already holding a reference.
// Perform a dummy transaction to ensure the context manager
// is registered before we create the first local reference
// to it (which will occur when creating the BpBinder).
// If a local reference is created for the BpBinder when the
// context manager is not present, the driver will fail to
// provide a reference to the context manager, but the
// driver API does not return status.
//
// Note that this is not race-free if the context manager
// dies while this code runs.
//
// TODO: add a driver API to wait for context manager, or
// stop special casing handle 0 for context manager and add
// a driver API to get a handle to the context manager with
// proper reference counting.
Parcel data;
status_t status = IPCThreadState::self()->transact(
0, IBinder::PING_TRANSACTION, data, nullptr, 0);
if (status == DEAD_OBJECT)
return nullptr;
}
b = BpBinder::create(handle);
e->binder = b;
if (b) e->refs = b->getWeakRefs();
result = b;
} else {
// This little bit of nastyness is to allow us to add a primary
// reference to the remote proxy when this team doesn't have one
// but another team is sending the handle to us.
result.force_set(b);
e->refs->decWeak(this);
}
}
return result;
}
wp<IBinder> ProcessState::getWeakProxyForHandle(int32_t handle)
{
wp<IBinder> result;
AutoMutex _l(mLock);
handle_entry* e = lookupHandleLocked(handle);
if (e != nullptr) {
// We need to create a new BpBinder if there isn't currently one, OR we
// are unable to acquire a weak reference on this current one. The
// attemptIncWeak() is safe because we know the BpBinder destructor will always
// call expungeHandle(), which acquires the same lock we are holding now.
// We need to do this because there is a race condition between someone
// releasing a reference on this BpBinder, and a new reference on its handle
// arriving from the driver.
IBinder* b = e->binder;
if (b == nullptr || !e->refs->attemptIncWeak(this)) {
b = BpBinder::create(handle);
result = b;
e->binder = b;
if (b) e->refs = b->getWeakRefs();
} else {
result = b;
e->refs->decWeak(this);
}
}
return result;
}
void ProcessState::expungeHandle(int32_t handle, IBinder* binder)
{
AutoMutex _l(mLock);
handle_entry* e = lookupHandleLocked(handle);
// This handle may have already been replaced with a new BpBinder
// (if someone failed the AttemptIncWeak() above); we don't want
// to overwrite it.
if (e && e->binder == binder) e->binder = nullptr;
}
String8 ProcessState::makeBinderThreadName() {
int32_t s = android_atomic_add(1, &mThreadPoolSeq);
pid_t pid = getpid();
String8 name;
name.appendFormat("Binder:%d_%X", pid, s);
return name;
}
void ProcessState::spawnPooledThread(bool isMain)
{
if (mThreadPoolStarted) {
String8 name = makeBinderThreadName();
ALOGV("Spawning new pooled thread, name=%s\n", name.string());
sp<Thread> t = new PoolThread(isMain);
t->run(name.string());
}
}
status_t ProcessState::setThreadPoolMaxThreadCount(size_t maxThreads) {
status_t result = NO_ERROR;
if (ioctl(mDriverFD, BINDER_SET_MAX_THREADS, &maxThreads) != -1) {
mMaxThreads = maxThreads;
} else {
result = -errno;
ALOGE("Binder ioctl to set max threads failed: %s", strerror(-result));
}
return result;
}
void ProcessState::giveThreadPoolName() {
androidSetThreadName( makeBinderThreadName().string() );
}
String8 ProcessState::getDriverName() {
return mDriverName;
}
static int open_driver(const char *driver)
{
int fd = open(driver, O_RDWR | O_CLOEXEC);
if (fd >= 0) {
int vers = 0;
status_t result = ioctl(fd, BINDER_VERSION, &vers);
if (result == -1) {
ALOGE("Binder ioctl to obtain version failed: %s", strerror(errno));
close(fd);
fd = -1;
}
if (result != 0 || vers != BINDER_CURRENT_PROTOCOL_VERSION) {
ALOGE("Binder driver protocol(%d) does not match user space protocol(%d)! ioctl() return value: %d",
vers, BINDER_CURRENT_PROTOCOL_VERSION, result);
close(fd);
fd = -1;
}
size_t maxThreads = DEFAULT_MAX_BINDER_THREADS;
result = ioctl(fd, BINDER_SET_MAX_THREADS, &maxThreads);
if (result == -1) {
ALOGE("Binder ioctl to set max threads failed: %s", strerror(errno));
}
} else {
ALOGW("Opening '%s' failed: %s\n", driver, strerror(errno));
}
return fd;
}
ProcessState::ProcessState(const char *driver)
: mDriverName(String8(driver))
, mDriverFD(open_driver(driver))
, mVMStart(MAP_FAILED)
, mThreadCountLock(PTHREAD_MUTEX_INITIALIZER)
, mThreadCountDecrement(PTHREAD_COND_INITIALIZER)
, mExecutingThreadsCount(0)
, mMaxThreads(DEFAULT_MAX_BINDER_THREADS)
, mStarvationStartTimeMs(0)
, mManagesContexts(false)
, mBinderContextCheckFunc(nullptr)
, mBinderContextUserData(nullptr)
, mThreadPoolStarted(false)
, mThreadPoolSeq(1)
, mCallRestriction(CallRestriction::NONE)
{
if (mDriverFD >= 0) {
// mmap the binder, providing a chunk of virtual address space to receive transactions.
mVMStart = mmap(nullptr, BINDER_VM_SIZE, PROT_READ, MAP_PRIVATE | MAP_NORESERVE, mDriverFD, 0);
if (mVMStart == MAP_FAILED) {
// *sigh*
ALOGE("Using %s failed: unable to mmap transaction memory.\n", mDriverName.c_str());
close(mDriverFD);
mDriverFD = -1;
mDriverName.clear();
}
}
LOG_ALWAYS_FATAL_IF(mDriverFD < 0, "Binder driver could not be opened. Terminating.");
}
ProcessState::~ProcessState()
{
if (mDriverFD >= 0) {
if (mVMStart != MAP_FAILED) {
munmap(mVMStart, BINDER_VM_SIZE);
}
close(mDriverFD);
}
mDriverFD = -1;
}
}; // namespace android