1 /* 2 * Copyright (C) 2005 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #define LOG_TAG "ProcessState" 18 19 #include <cutils/process_name.h> 20 21 #include <binder/ProcessState.h> 22 23 #include <utils/Atomic.h> 24 #include <binder/BpBinder.h> 25 #include <binder/IPCThreadState.h> 26 #include <utils/Log.h> 27 #include <utils/String8.h> 28 #include <binder/IServiceManager.h> 29 #include <utils/String8.h> 30 #include <utils/threads.h> 31 32 #include <private/binder/binder_module.h> 33 #include <private/binder/Static.h> 34 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <unistd.h> 40 #include <sys/ioctl.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/types.h> 44 45 #define BINDER_VM_SIZE ((1*1024*1024) - (4096 *2)) 46 #define DEFAULT_MAX_BINDER_THREADS 15 47 48 // ------------------------------------------------------------------------- 49 50 namespace android { 51 52 class PoolThread : public Thread 53 { 54 public: 55 PoolThread(bool isMain) 56 : mIsMain(isMain) 57 { 58 } 59 60 protected: 61 virtual bool threadLoop() 62 { 63 IPCThreadState::self()->joinThreadPool(mIsMain); 64 return false; 65 } 66 67 const bool mIsMain; 68 }; 69 70 sp<ProcessState> ProcessState::self() 71 { 72 Mutex::Autolock _l(gProcessMutex); 73 if (gProcess != NULL) { 74 return gProcess; 75 } 76 gProcess = new ProcessState; 77 return gProcess; 78 } 79 80 void ProcessState::setContextObject(const sp<IBinder>& object) 81 { 82 setContextObject(object, String16("default")); 83 } 84 85 sp<IBinder> ProcessState::getContextObject(const sp<IBinder>& /*caller*/) 86 { 87 return getStrongProxyForHandle(0); 88 } 89 90 void ProcessState::setContextObject(const sp<IBinder>& object, const String16& name) 91 { 92 AutoMutex _l(mLock); 93 mContexts.add(name, object); 94 } 95 96 sp<IBinder> ProcessState::getContextObject(const String16& name, const sp<IBinder>& caller) 97 { 98 mLock.lock(); 99 sp<IBinder> object( 100 mContexts.indexOfKey(name) >= 0 ? mContexts.valueFor(name) : NULL); 101 mLock.unlock(); 102 103 //printf("Getting context object %s for %p\n", String8(name).string(), caller.get()); 104 105 if (object != NULL) return object; 106 107 // Don't attempt to retrieve contexts if we manage them 108 if (mManagesContexts) { 109 ALOGE("getContextObject(%s) failed, but we manage the contexts!\n", 110 String8(name).string()); 111 return NULL; 112 } 113 114 IPCThreadState* ipc = IPCThreadState::self(); 115 { 116 Parcel data, reply; 117 // no interface token on this magic transaction 118 data.writeString16(name); 119 data.writeStrongBinder(caller); 120 status_t result = ipc->transact(0 /*magic*/, 0, data, &reply, 0); 121 if (result == NO_ERROR) { 122 object = reply.readStrongBinder(); 123 } 124 } 125 126 ipc->flushCommands(); 127 128 if (object != NULL) setContextObject(object, name); 129 return object; 130 } 131 132 void ProcessState::startThreadPool() 133 { 134 AutoMutex _l(mLock); 135 if (!mThreadPoolStarted) { 136 mThreadPoolStarted = true; 137 spawnPooledThread(true); 138 } 139 } 140 141 bool ProcessState::isContextManager(void) const 142 { 143 return mManagesContexts; 144 } 145 146 bool ProcessState::becomeContextManager(context_check_func checkFunc, void* userData) 147 { 148 if (!mManagesContexts) { 149 AutoMutex _l(mLock); 150 mBinderContextCheckFunc = checkFunc; 151 mBinderContextUserData = userData; 152 153 int dummy = 0; 154 status_t result = ioctl(mDriverFD, BINDER_SET_CONTEXT_MGR, &dummy); 155 if (result == 0) { 156 mManagesContexts = true; 157 } else if (result == -1) { 158 mBinderContextCheckFunc = NULL; 159 mBinderContextUserData = NULL; 160 ALOGE("Binder ioctl to become context manager failed: %s\n", strerror(errno)); 161 } 162 } 163 return mManagesContexts; 164 } 165 166 ProcessState::handle_entry* ProcessState::lookupHandleLocked(int32_t handle) 167 { 168 const size_t N=mHandleToObject.size(); 169 if (N <= (size_t)handle) { 170 handle_entry e; 171 e.binder = NULL; 172 e.refs = NULL; 173 status_t err = mHandleToObject.insertAt(e, N, handle+1-N); 174 if (err < NO_ERROR) return NULL; 175 } 176 return &mHandleToObject.editItemAt(handle); 177 } 178 179 sp<IBinder> ProcessState::getStrongProxyForHandle(int32_t handle) 180 { 181 sp<IBinder> result; 182 183 AutoMutex _l(mLock); 184 185 handle_entry* e = lookupHandleLocked(handle); 186 187 if (e != NULL) { 188 // We need to create a new BpBinder if there isn't currently one, OR we 189 // are unable to acquire a weak reference on this current one. See comment 190 // in getWeakProxyForHandle() for more info about this. 191 IBinder* b = e->binder; 192 if (b == NULL || !e->refs->attemptIncWeak(this)) { 193 if (handle == 0) { 194 // Special case for context manager... 195 // The context manager is the only object for which we create 196 // a BpBinder proxy without already holding a reference. 197 // Perform a dummy transaction to ensure the context manager 198 // is registered before we create the first local reference 199 // to it (which will occur when creating the BpBinder). 200 // If a local reference is created for the BpBinder when the 201 // context manager is not present, the driver will fail to 202 // provide a reference to the context manager, but the 203 // driver API does not return status. 204 // 205 // Note that this is not race-free if the context manager 206 // dies while this code runs. 207 // 208 // TODO: add a driver API to wait for context manager, or 209 // stop special casing handle 0 for context manager and add 210 // a driver API to get a handle to the context manager with 211 // proper reference counting. 212 213 Parcel data; 214 status_t status = IPCThreadState::self()->transact( 215 0, IBinder::PING_TRANSACTION, data, NULL, 0); 216 if (status == DEAD_OBJECT) 217 return NULL; 218 } 219 220 b = new BpBinder(handle); 221 e->binder = b; 222 if (b) e->refs = b->getWeakRefs(); 223 result = b; 224 } else { 225 // This little bit of nastyness is to allow us to add a primary 226 // reference to the remote proxy when this team doesn't have one 227 // but another team is sending the handle to us. 228 result.force_set(b); 229 e->refs->decWeak(this); 230 } 231 } 232 233 return result; 234 } 235 236 wp<IBinder> ProcessState::getWeakProxyForHandle(int32_t handle) 237 { 238 wp<IBinder> result; 239 240 AutoMutex _l(mLock); 241 242 handle_entry* e = lookupHandleLocked(handle); 243 244 if (e != NULL) { 245 // We need to create a new BpBinder if there isn't currently one, OR we 246 // are unable to acquire a weak reference on this current one. The 247 // attemptIncWeak() is safe because we know the BpBinder destructor will always 248 // call expungeHandle(), which acquires the same lock we are holding now. 249 // We need to do this because there is a race condition between someone 250 // releasing a reference on this BpBinder, and a new reference on its handle 251 // arriving from the driver. 252 IBinder* b = e->binder; 253 if (b == NULL || !e->refs->attemptIncWeak(this)) { 254 b = new BpBinder(handle); 255 result = b; 256 e->binder = b; 257 if (b) e->refs = b->getWeakRefs(); 258 } else { 259 result = b; 260 e->refs->decWeak(this); 261 } 262 } 263 264 return result; 265 } 266 267 void ProcessState::expungeHandle(int32_t handle, IBinder* binder) 268 { 269 AutoMutex _l(mLock); 270 271 handle_entry* e = lookupHandleLocked(handle); 272 273 // This handle may have already been replaced with a new BpBinder 274 // (if someone failed the AttemptIncWeak() above); we don't want 275 // to overwrite it. 276 if (e && e->binder == binder) e->binder = NULL; 277 } 278 279 String8 ProcessState::makeBinderThreadName() { 280 int32_t s = android_atomic_add(1, &mThreadPoolSeq); 281 pid_t pid = getpid(); 282 String8 name; 283 name.appendFormat("Binder:%d_%X", pid, s); 284 return name; 285 } 286 287 void ProcessState::spawnPooledThread(bool isMain) 288 { 289 if (mThreadPoolStarted) { 290 String8 name = makeBinderThreadName(); 291 ALOGV("Spawning new pooled thread, name=%s\n", name.string()); 292 sp<Thread> t = new PoolThread(isMain); 293 t->run(name.string()); 294 } 295 } 296 297 status_t ProcessState::setThreadPoolMaxThreadCount(size_t maxThreads) { 298 status_t result = NO_ERROR; 299 if (ioctl(mDriverFD, BINDER_SET_MAX_THREADS, &maxThreads) != -1) { 300 mMaxThreads = maxThreads; 301 } else { 302 result = -errno; 303 ALOGE("Binder ioctl to set max threads failed: %s", strerror(-result)); 304 } 305 return result; 306 } 307 308 void ProcessState::giveThreadPoolName() { 309 androidSetThreadName( makeBinderThreadName().string() ); 310 } 311 312 static int open_driver() 313 { 314 int fd = open("/dev/binder", O_RDWR | O_CLOEXEC); 315 if (fd >= 0) { 316 int vers = 0; 317 status_t result = ioctl(fd, BINDER_VERSION, &vers); 318 if (result == -1) { 319 ALOGE("Binder ioctl to obtain version failed: %s", strerror(errno)); 320 close(fd); 321 fd = -1; 322 } 323 if (result != 0 || vers != BINDER_CURRENT_PROTOCOL_VERSION) { 324 ALOGE("Binder driver protocol does not match user space protocol!"); 325 close(fd); 326 fd = -1; 327 } 328 size_t maxThreads = DEFAULT_MAX_BINDER_THREADS; 329 result = ioctl(fd, BINDER_SET_MAX_THREADS, &maxThreads); 330 if (result == -1) { 331 ALOGE("Binder ioctl to set max threads failed: %s", strerror(errno)); 332 } 333 } else { 334 ALOGW("Opening '/dev/binder' failed: %s\n", strerror(errno)); 335 } 336 return fd; 337 } 338 339 ProcessState::ProcessState() 340 : mDriverFD(open_driver()) 341 , mVMStart(MAP_FAILED) 342 , mThreadCountLock(PTHREAD_MUTEX_INITIALIZER) 343 , mThreadCountDecrement(PTHREAD_COND_INITIALIZER) 344 , mExecutingThreadsCount(0) 345 , mMaxThreads(DEFAULT_MAX_BINDER_THREADS) 346 , mStarvationStartTimeMs(0) 347 , mManagesContexts(false) 348 , mBinderContextCheckFunc(NULL) 349 , mBinderContextUserData(NULL) 350 , mThreadPoolStarted(false) 351 , mThreadPoolSeq(1) 352 { 353 if (mDriverFD >= 0) { 354 // mmap the binder, providing a chunk of virtual address space to receive transactions. 355 mVMStart = mmap(0, BINDER_VM_SIZE, PROT_READ, MAP_PRIVATE | MAP_NORESERVE, mDriverFD, 0); 356 if (mVMStart == MAP_FAILED) { 357 // *sigh* 358 ALOGE("Using /dev/binder failed: unable to mmap transaction memory.\n"); 359 close(mDriverFD); 360 mDriverFD = -1; 361 } 362 } 363 364 LOG_ALWAYS_FATAL_IF(mDriverFD < 0, "Binder driver could not be opened. Terminating."); 365 } 366 367 ProcessState::~ProcessState() 368 { 369 } 370 371 }; // namespace android 372