1 /* 2 * Main entry of app process. 3 * 4 * Starts the interpreted runtime, then starts up the application. 5 * 6 */ 7 8 #define LOG_TAG "appproc" 9 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <sys/prctl.h> 13 #include <sys/stat.h> 14 #include <unistd.h> 15 16 #include <binder/IPCThreadState.h> 17 #include <binder/ProcessState.h> 18 #include <utils/Log.h> 19 #include <cutils/memory.h> 20 #include <cutils/process_name.h> 21 #include <cutils/properties.h> 22 #include <cutils/trace.h> 23 #include <android_runtime/AndroidRuntime.h> 24 #include <private/android_filesystem_config.h> // for AID_SYSTEM 25 26 namespace android { 27 28 static void app_usage() 29 { 30 fprintf(stderr, 31 "Usage: app_process [java-options] cmd-dir start-class-name [options]\n"); 32 } 33 34 class AppRuntime : public AndroidRuntime 35 { 36 public: 37 AppRuntime(char* argBlockStart, const size_t argBlockLength) 38 : AndroidRuntime(argBlockStart, argBlockLength) 39 , mClass(NULL) 40 { 41 } 42 43 void setClassNameAndArgs(const String8& className, int argc, char * const *argv) { 44 mClassName = className; 45 for (int i = 0; i < argc; ++i) { 46 mArgs.add(String8(argv[i])); 47 } 48 } 49 50 virtual void onVmCreated(JNIEnv* env) 51 { 52 if (mClassName.isEmpty()) { 53 return; // Zygote. Nothing to do here. 54 } 55 56 /* 57 * This is a little awkward because the JNI FindClass call uses the 58 * class loader associated with the native method we're executing in. 59 * If called in onStarted (from RuntimeInit.finishInit because we're 60 * launching "am", for example), FindClass would see that we're calling 61 * from a boot class' native method, and so wouldn't look for the class 62 * we're trying to look up in CLASSPATH. Unfortunately it needs to, 63 * because the "am" classes are not boot classes. 64 * 65 * The easiest fix is to call FindClass here, early on before we start 66 * executing boot class Java code and thereby deny ourselves access to 67 * non-boot classes. 68 */ 69 char* slashClassName = toSlashClassName(mClassName.string()); 70 mClass = env->FindClass(slashClassName); 71 if (mClass == NULL) { 72 ALOGE("ERROR: could not find class '%s'\n", mClassName.string()); 73 } 74 free(slashClassName); 75 76 mClass = reinterpret_cast<jclass>(env->NewGlobalRef(mClass)); 77 } 78 79 virtual void onStarted() 80 { 81 sp<ProcessState> proc = ProcessState::self(); 82 ALOGV("App process: starting thread pool.\n"); 83 proc->startThreadPool(); 84 85 AndroidRuntime* ar = AndroidRuntime::getRuntime(); 86 ar->callMain(mClassName, mClass, mArgs); 87 88 IPCThreadState::self()->stopProcess(); 89 } 90 91 virtual void onZygoteInit() 92 { 93 sp<ProcessState> proc = ProcessState::self(); 94 ALOGV("App process: starting thread pool.\n"); 95 proc->startThreadPool(); 96 } 97 98 virtual void onExit(int code) 99 { 100 if (mClassName.isEmpty()) { 101 // if zygote 102 IPCThreadState::self()->stopProcess(); 103 } 104 105 AndroidRuntime::onExit(code); 106 } 107 108 109 String8 mClassName; 110 Vector<String8> mArgs; 111 jclass mClass; 112 }; 113 114 } 115 116 using namespace android; 117 118 static size_t computeArgBlockSize(int argc, char* const argv[]) { 119 // TODO: This assumes that all arguments are allocated in 120 // contiguous memory. There isn't any documented guarantee 121 // that this is the case, but this is how the kernel does it 122 // (see fs/exec.c). 123 // 124 // Also note that this is a constant for "normal" android apps. 125 // Since they're forked from zygote, the size of their command line 126 // is the size of the zygote command line. 127 // 128 // We change the process name of the process by over-writing 129 // the start of the argument block (argv[0]) with the new name of 130 // the process, so we'd mysteriously start getting truncated process 131 // names if the zygote command line decreases in size. 132 uintptr_t start = reinterpret_cast<uintptr_t>(argv[0]); 133 uintptr_t end = reinterpret_cast<uintptr_t>(argv[argc - 1]); 134 end += strlen(argv[argc - 1]) + 1; 135 return (end - start); 136 } 137 138 static void maybeCreateDalvikCache() { 139 #if defined(__aarch64__) 140 static const char kInstructionSet[] = "arm64"; 141 #elif defined(__x86_64__) 142 static const char kInstructionSet[] = "x86_64"; 143 #elif defined(__arm__) 144 static const char kInstructionSet[] = "arm"; 145 #elif defined(__i386__) 146 static const char kInstructionSet[] = "x86"; 147 #elif defined (__mips__) && !defined(__LP64__) 148 static const char kInstructionSet[] = "mips"; 149 #elif defined (__mips__) && defined(__LP64__) 150 static const char kInstructionSet[] = "mips64"; 151 #else 152 #error "Unknown instruction set" 153 #endif 154 const char* androidRoot = getenv("ANDROID_DATA"); 155 LOG_ALWAYS_FATAL_IF(androidRoot == NULL, "ANDROID_DATA environment variable unset"); 156 157 char dalvikCacheDir[PATH_MAX]; 158 const int numChars = snprintf(dalvikCacheDir, PATH_MAX, 159 "%s/dalvik-cache/%s", androidRoot, kInstructionSet); 160 LOG_ALWAYS_FATAL_IF((numChars >= PATH_MAX || numChars < 0), 161 "Error constructing dalvik cache : %s", strerror(errno)); 162 163 int result = mkdir(dalvikCacheDir, 0711); 164 LOG_ALWAYS_FATAL_IF((result < 0 && errno != EEXIST), 165 "Error creating cache dir %s : %s", dalvikCacheDir, strerror(errno)); 166 167 // We always perform these steps because the directory might 168 // already exist, with wider permissions and a different owner 169 // than we'd like. 170 result = chown(dalvikCacheDir, AID_ROOT, AID_ROOT); 171 LOG_ALWAYS_FATAL_IF((result < 0), "Error changing dalvik-cache ownership : %s", strerror(errno)); 172 173 result = chmod(dalvikCacheDir, 0711); 174 LOG_ALWAYS_FATAL_IF((result < 0), 175 "Error changing dalvik-cache permissions : %s", strerror(errno)); 176 } 177 178 #if defined(__LP64__) 179 static const char ABI_LIST_PROPERTY[] = "ro.product.cpu.abilist64"; 180 static const char ZYGOTE_NICE_NAME[] = "zygote64"; 181 #else 182 static const char ABI_LIST_PROPERTY[] = "ro.product.cpu.abilist32"; 183 static const char ZYGOTE_NICE_NAME[] = "zygote"; 184 #endif 185 186 int main(int argc, char* const argv[]) 187 { 188 if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) { 189 // Older kernels don't understand PR_SET_NO_NEW_PRIVS and return 190 // EINVAL. Don't die on such kernels. 191 if (errno != EINVAL) { 192 LOG_ALWAYS_FATAL("PR_SET_NO_NEW_PRIVS failed: %s", strerror(errno)); 193 return 12; 194 } 195 } 196 197 AppRuntime runtime(argv[0], computeArgBlockSize(argc, argv)); 198 // Process command line arguments 199 // ignore argv[0] 200 argc--; 201 argv++; 202 203 // Everything up to '--' or first non '-' arg goes to the vm. 204 // 205 // The first argument after the VM args is the "parent dir", which 206 // is currently unused. 207 // 208 // After the parent dir, we expect one or more the following internal 209 // arguments : 210 // 211 // --zygote : Start in zygote mode 212 // --start-system-server : Start the system server. 213 // --application : Start in application (stand alone, non zygote) mode. 214 // --nice-name : The nice name for this process. 215 // 216 // For non zygote starts, these arguments will be followed by 217 // the main class name. All remaining arguments are passed to 218 // the main method of this class. 219 // 220 // For zygote starts, all remaining arguments are passed to the zygote. 221 // main function. 222 // 223 // Note that we must copy argument string values since we will rewrite the 224 // entire argument block when we apply the nice name to argv0. 225 226 int i; 227 for (i = 0; i < argc; i++) { 228 if (argv[i][0] != '-') { 229 break; 230 } 231 if (argv[i][1] == '-' && argv[i][2] == 0) { 232 ++i; // Skip --. 233 break; 234 } 235 runtime.addOption(strdup(argv[i])); 236 } 237 238 // Parse runtime arguments. Stop at first unrecognized option. 239 bool zygote = false; 240 bool startSystemServer = false; 241 bool application = false; 242 String8 niceName; 243 String8 className; 244 245 ++i; // Skip unused "parent dir" argument. 246 while (i < argc) { 247 const char* arg = argv[i++]; 248 if (strcmp(arg, "--zygote") == 0) { 249 zygote = true; 250 niceName = ZYGOTE_NICE_NAME; 251 } else if (strcmp(arg, "--start-system-server") == 0) { 252 startSystemServer = true; 253 } else if (strcmp(arg, "--application") == 0) { 254 application = true; 255 } else if (strncmp(arg, "--nice-name=", 12) == 0) { 256 niceName.setTo(arg + 12); 257 } else if (strncmp(arg, "--", 2) != 0) { 258 className.setTo(arg); 259 break; 260 } else { 261 --i; 262 break; 263 } 264 } 265 266 Vector<String8> args; 267 if (!className.isEmpty()) { 268 // We're not in zygote mode, the only argument we need to pass 269 // to RuntimeInit is the application argument. 270 // 271 // The Remainder of args get passed to startup class main(). Make 272 // copies of them before we overwrite them with the process name. 273 args.add(application ? String8("application") : String8("tool")); 274 runtime.setClassNameAndArgs(className, argc - i, argv + i); 275 } else { 276 // We're in zygote mode. 277 maybeCreateDalvikCache(); 278 279 if (startSystemServer) { 280 args.add(String8("start-system-server")); 281 } 282 283 char prop[PROP_VALUE_MAX]; 284 if (property_get(ABI_LIST_PROPERTY, prop, NULL) == 0) { 285 LOG_ALWAYS_FATAL("app_process: Unable to determine ABI list from property %s.", 286 ABI_LIST_PROPERTY); 287 return 11; 288 } 289 290 String8 abiFlag("--abi-list="); 291 abiFlag.append(prop); 292 args.add(abiFlag); 293 294 // In zygote mode, pass all remaining arguments to the zygote 295 // main() method. 296 for (; i < argc; ++i) { 297 args.add(String8(argv[i])); 298 } 299 } 300 301 if (!niceName.isEmpty()) { 302 runtime.setArgv0(niceName.string()); 303 set_process_name(niceName.string()); 304 } 305 306 if (zygote) { 307 runtime.start("com.android.internal.os.ZygoteInit", args, zygote); 308 } else if (className) { 309 runtime.start("com.android.internal.os.RuntimeInit", args, zygote); 310 } else { 311 fprintf(stderr, "Error: no class name or --zygote supplied.\n"); 312 app_usage(); 313 LOG_ALWAYS_FATAL("app_process: no class name or --zygote supplied."); 314 return 10; 315 } 316 } 317