1/* 2 * Copyright (C) 2008 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 "Zygote" 18 19// sys/mount.h has to come before linux/fs.h due to redefinition of MS_RDONLY, MS_BIND, etc 20#include <sys/mount.h> 21#include <linux/fs.h> 22 23#include <list> 24#include <sstream> 25#include <string> 26 27#include <fcntl.h> 28#include <grp.h> 29#include <inttypes.h> 30#include <mntent.h> 31#include <paths.h> 32#include <signal.h> 33#include <stdlib.h> 34#include <sys/capability.h> 35#include <sys/personality.h> 36#include <sys/prctl.h> 37#include <sys/resource.h> 38#include <sys/stat.h> 39#include <sys/types.h> 40#include <sys/utsname.h> 41#include <sys/wait.h> 42#include <unistd.h> 43 44#include <cutils/fs.h> 45#include <cutils/multiuser.h> 46#include <cutils/sched_policy.h> 47#include <private/android_filesystem_config.h> 48#include <utils/String8.h> 49#include <selinux/android.h> 50#include <processgroup/processgroup.h> 51 52#include "core_jni_helpers.h" 53#include "JNIHelp.h" 54#include "ScopedLocalRef.h" 55#include "ScopedPrimitiveArray.h" 56#include "ScopedUtfChars.h" 57 58#include "nativebridge/native_bridge.h" 59 60namespace { 61 62using android::String8; 63 64static pid_t gSystemServerPid = 0; 65 66static const char kZygoteClassName[] = "com/android/internal/os/Zygote"; 67static jclass gZygoteClass; 68static jmethodID gCallPostForkChildHooks; 69 70// Must match values in com.android.internal.os.Zygote. 71enum MountExternalKind { 72 MOUNT_EXTERNAL_NONE = 0, 73 MOUNT_EXTERNAL_DEFAULT = 1, 74 MOUNT_EXTERNAL_READ = 2, 75 MOUNT_EXTERNAL_WRITE = 3, 76}; 77 78static void RuntimeAbort(JNIEnv* env, int line, const char* msg) { 79 std::ostringstream oss; 80 oss << __FILE__ << ":" << line << ": " << msg; 81 env->FatalError(oss.str().c_str()); 82} 83 84// This signal handler is for zygote mode, since the zygote must reap its children 85static void SigChldHandler(int /*signal_number*/) { 86 pid_t pid; 87 int status; 88 89 // It's necessary to save and restore the errno during this function. 90 // Since errno is stored per thread, changing it here modifies the errno 91 // on the thread on which this signal handler executes. If a signal occurs 92 // between a call and an errno check, it's possible to get the errno set 93 // here. 94 // See b/23572286 for extra information. 95 int saved_errno = errno; 96 97 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) { 98 // Log process-death status that we care about. In general it is 99 // not safe to call LOG(...) from a signal handler because of 100 // possible reentrancy. However, we know a priori that the 101 // current implementation of LOG() is safe to call from a SIGCHLD 102 // handler in the zygote process. If the LOG() implementation 103 // changes its locking strategy or its use of syscalls within the 104 // lazy-init critical section, its use here may become unsafe. 105 if (WIFEXITED(status)) { 106 if (WEXITSTATUS(status)) { 107 ALOGI("Process %d exited cleanly (%d)", pid, WEXITSTATUS(status)); 108 } 109 } else if (WIFSIGNALED(status)) { 110 if (WTERMSIG(status) != SIGKILL) { 111 ALOGI("Process %d exited due to signal (%d)", pid, WTERMSIG(status)); 112 } 113 if (WCOREDUMP(status)) { 114 ALOGI("Process %d dumped core.", pid); 115 } 116 } 117 118 // If the just-crashed process is the system_server, bring down zygote 119 // so that it is restarted by init and system server will be restarted 120 // from there. 121 if (pid == gSystemServerPid) { 122 ALOGE("Exit zygote because system server (%d) has terminated", pid); 123 kill(getpid(), SIGKILL); 124 } 125 } 126 127 // Note that we shouldn't consider ECHILD an error because 128 // the secondary zygote might have no children left to wait for. 129 if (pid < 0 && errno != ECHILD) { 130 ALOGW("Zygote SIGCHLD error in waitpid: %s", strerror(errno)); 131 } 132 133 errno = saved_errno; 134} 135 136// Configures the SIGCHLD handler for the zygote process. This is configured 137// very late, because earlier in the runtime we may fork() and exec() 138// other processes, and we want to waitpid() for those rather than 139// have them be harvested immediately. 140// 141// This ends up being called repeatedly before each fork(), but there's 142// no real harm in that. 143static void SetSigChldHandler() { 144 struct sigaction sa; 145 memset(&sa, 0, sizeof(sa)); 146 sa.sa_handler = SigChldHandler; 147 148 int err = sigaction(SIGCHLD, &sa, NULL); 149 if (err < 0) { 150 ALOGW("Error setting SIGCHLD handler: %s", strerror(errno)); 151 } 152} 153 154// Sets the SIGCHLD handler back to default behavior in zygote children. 155static void UnsetSigChldHandler() { 156 struct sigaction sa; 157 memset(&sa, 0, sizeof(sa)); 158 sa.sa_handler = SIG_DFL; 159 160 int err = sigaction(SIGCHLD, &sa, NULL); 161 if (err < 0) { 162 ALOGW("Error unsetting SIGCHLD handler: %s", strerror(errno)); 163 } 164} 165 166// Calls POSIX setgroups() using the int[] object as an argument. 167// A NULL argument is tolerated. 168static void SetGids(JNIEnv* env, jintArray javaGids) { 169 if (javaGids == NULL) { 170 return; 171 } 172 173 ScopedIntArrayRO gids(env, javaGids); 174 if (gids.get() == NULL) { 175 RuntimeAbort(env, __LINE__, "Getting gids int array failed"); 176 } 177 int rc = setgroups(gids.size(), reinterpret_cast<const gid_t*>(&gids[0])); 178 if (rc == -1) { 179 RuntimeAbort(env, __LINE__, "setgroups failed"); 180 } 181} 182 183// Sets the resource limits via setrlimit(2) for the values in the 184// two-dimensional array of integers that's passed in. The second dimension 185// contains a tuple of length 3: (resource, rlim_cur, rlim_max). NULL is 186// treated as an empty array. 187static void SetRLimits(JNIEnv* env, jobjectArray javaRlimits) { 188 if (javaRlimits == NULL) { 189 return; 190 } 191 192 rlimit rlim; 193 memset(&rlim, 0, sizeof(rlim)); 194 195 for (int i = 0; i < env->GetArrayLength(javaRlimits); ++i) { 196 ScopedLocalRef<jobject> javaRlimitObject(env, env->GetObjectArrayElement(javaRlimits, i)); 197 ScopedIntArrayRO javaRlimit(env, reinterpret_cast<jintArray>(javaRlimitObject.get())); 198 if (javaRlimit.size() != 3) { 199 RuntimeAbort(env, __LINE__, "rlimits array must have a second dimension of size 3"); 200 } 201 202 rlim.rlim_cur = javaRlimit[1]; 203 rlim.rlim_max = javaRlimit[2]; 204 205 int rc = setrlimit(javaRlimit[0], &rlim); 206 if (rc == -1) { 207 ALOGE("setrlimit(%d, {%ld, %ld}) failed", javaRlimit[0], rlim.rlim_cur, 208 rlim.rlim_max); 209 RuntimeAbort(env, __LINE__, "setrlimit failed"); 210 } 211 } 212} 213 214// The debug malloc library needs to know whether it's the zygote or a child. 215extern "C" int gMallocLeakZygoteChild; 216 217static void EnableKeepCapabilities(JNIEnv* env) { 218 int rc = prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0); 219 if (rc == -1) { 220 RuntimeAbort(env, __LINE__, "prctl(PR_SET_KEEPCAPS) failed"); 221 } 222} 223 224static void DropCapabilitiesBoundingSet(JNIEnv* env) { 225 for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) { 226 int rc = prctl(PR_CAPBSET_DROP, i, 0, 0, 0); 227 if (rc == -1) { 228 if (errno == EINVAL) { 229 ALOGE("prctl(PR_CAPBSET_DROP) failed with EINVAL. Please verify " 230 "your kernel is compiled with file capabilities support"); 231 } else { 232 RuntimeAbort(env, __LINE__, "prctl(PR_CAPBSET_DROP) failed"); 233 } 234 } 235 } 236} 237 238static void SetCapabilities(JNIEnv* env, int64_t permitted, int64_t effective) { 239 __user_cap_header_struct capheader; 240 memset(&capheader, 0, sizeof(capheader)); 241 capheader.version = _LINUX_CAPABILITY_VERSION_3; 242 capheader.pid = 0; 243 244 __user_cap_data_struct capdata[2]; 245 memset(&capdata, 0, sizeof(capdata)); 246 capdata[0].effective = effective; 247 capdata[1].effective = effective >> 32; 248 capdata[0].permitted = permitted; 249 capdata[1].permitted = permitted >> 32; 250 251 if (capset(&capheader, &capdata[0]) == -1) { 252 ALOGE("capset(%" PRId64 ", %" PRId64 ") failed", permitted, effective); 253 RuntimeAbort(env, __LINE__, "capset failed"); 254 } 255} 256 257static void SetSchedulerPolicy(JNIEnv* env) { 258 errno = -set_sched_policy(0, SP_DEFAULT); 259 if (errno != 0) { 260 ALOGE("set_sched_policy(0, SP_DEFAULT) failed"); 261 RuntimeAbort(env, __LINE__, "set_sched_policy(0, SP_DEFAULT) failed"); 262 } 263} 264 265static int UnmountTree(const char* path) { 266 size_t path_len = strlen(path); 267 268 FILE* fp = setmntent("/proc/mounts", "r"); 269 if (fp == NULL) { 270 ALOGE("Error opening /proc/mounts: %s", strerror(errno)); 271 return -errno; 272 } 273 274 // Some volumes can be stacked on each other, so force unmount in 275 // reverse order to give us the best chance of success. 276 std::list<std::string> toUnmount; 277 mntent* mentry; 278 while ((mentry = getmntent(fp)) != NULL) { 279 if (strncmp(mentry->mnt_dir, path, path_len) == 0) { 280 toUnmount.push_front(std::string(mentry->mnt_dir)); 281 } 282 } 283 endmntent(fp); 284 285 for (auto path : toUnmount) { 286 if (umount2(path.c_str(), MNT_DETACH)) { 287 ALOGW("Failed to unmount %s: %s", path.c_str(), strerror(errno)); 288 } 289 } 290 return 0; 291} 292 293// Create a private mount namespace and bind mount appropriate emulated 294// storage for the given user. 295static bool MountEmulatedStorage(uid_t uid, jint mount_mode, 296 bool force_mount_namespace) { 297 // See storage config details at http://source.android.com/tech/storage/ 298 299 // Create a second private mount namespace for our process 300 if (unshare(CLONE_NEWNS) == -1) { 301 ALOGW("Failed to unshare(): %s", strerror(errno)); 302 return false; 303 } 304 305 String8 storageSource; 306 if (mount_mode == MOUNT_EXTERNAL_DEFAULT) { 307 storageSource = "/mnt/runtime/default"; 308 } else if (mount_mode == MOUNT_EXTERNAL_READ) { 309 storageSource = "/mnt/runtime/read"; 310 } else if (mount_mode == MOUNT_EXTERNAL_WRITE) { 311 storageSource = "/mnt/runtime/write"; 312 } else { 313 // Sane default of no storage visible 314 return true; 315 } 316 if (TEMP_FAILURE_RETRY(mount(storageSource.string(), "/storage", 317 NULL, MS_BIND | MS_REC | MS_SLAVE, NULL)) == -1) { 318 ALOGW("Failed to mount %s to /storage: %s", storageSource.string(), strerror(errno)); 319 return false; 320 } 321 322 // Mount user-specific symlink helper into place 323 userid_t user_id = multiuser_get_user_id(uid); 324 const String8 userSource(String8::format("/mnt/user/%d", user_id)); 325 if (fs_prepare_dir(userSource.string(), 0751, 0, 0) == -1) { 326 return false; 327 } 328 if (TEMP_FAILURE_RETRY(mount(userSource.string(), "/storage/self", 329 NULL, MS_BIND, NULL)) == -1) { 330 ALOGW("Failed to mount %s to /storage/self: %s", userSource.string(), strerror(errno)); 331 return false; 332 } 333 334 return true; 335} 336 337static bool NeedsNoRandomizeWorkaround() { 338#if !defined(__arm__) 339 return false; 340#else 341 int major; 342 int minor; 343 struct utsname uts; 344 if (uname(&uts) == -1) { 345 return false; 346 } 347 348 if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) { 349 return false; 350 } 351 352 // Kernels before 3.4.* need the workaround. 353 return (major < 3) || ((major == 3) && (minor < 4)); 354#endif 355} 356 357// Utility to close down the Zygote socket file descriptors while 358// the child is still running as root with Zygote's privileges. Each 359// descriptor (if any) is closed via dup2(), replacing it with a valid 360// (open) descriptor to /dev/null. 361 362static void DetachDescriptors(JNIEnv* env, jintArray fdsToClose) { 363 if (!fdsToClose) { 364 return; 365 } 366 jsize count = env->GetArrayLength(fdsToClose); 367 ScopedIntArrayRO ar(env, fdsToClose); 368 if (ar.get() == NULL) { 369 RuntimeAbort(env, __LINE__, "Bad fd array"); 370 } 371 jsize i; 372 int devnull; 373 for (i = 0; i < count; i++) { 374 devnull = open("/dev/null", O_RDWR); 375 if (devnull < 0) { 376 ALOGE("Failed to open /dev/null: %s", strerror(errno)); 377 RuntimeAbort(env, __LINE__, "Failed to open /dev/null"); 378 continue; 379 } 380 ALOGV("Switching descriptor %d to /dev/null: %s", ar[i], strerror(errno)); 381 if (dup2(devnull, ar[i]) < 0) { 382 ALOGE("Failed dup2() on descriptor %d: %s", ar[i], strerror(errno)); 383 RuntimeAbort(env, __LINE__, "Failed dup2()"); 384 } 385 close(devnull); 386 } 387} 388 389void SetThreadName(const char* thread_name) { 390 bool hasAt = false; 391 bool hasDot = false; 392 const char* s = thread_name; 393 while (*s) { 394 if (*s == '.') { 395 hasDot = true; 396 } else if (*s == '@') { 397 hasAt = true; 398 } 399 s++; 400 } 401 const int len = s - thread_name; 402 if (len < 15 || hasAt || !hasDot) { 403 s = thread_name; 404 } else { 405 s = thread_name + len - 15; 406 } 407 // pthread_setname_np fails rather than truncating long strings. 408 char buf[16]; // MAX_TASK_COMM_LEN=16 is hard-coded into bionic 409 strlcpy(buf, s, sizeof(buf)-1); 410 errno = pthread_setname_np(pthread_self(), buf); 411 if (errno != 0) { 412 ALOGW("Unable to set the name of current thread to '%s': %s", buf, strerror(errno)); 413 } 414} 415 416#ifdef ENABLE_SCHED_BOOST 417static void SetForkLoad(bool boost) { 418 // set scheduler knob to boost forked processes 419 pid_t currentPid = getpid(); 420 // fits at most "/proc/XXXXXXX/sched_init_task_load\0" 421 char schedPath[35]; 422 snprintf(schedPath, sizeof(schedPath), "/proc/%u/sched_init_task_load", currentPid); 423 int schedBoostFile = open(schedPath, O_WRONLY); 424 if (schedBoostFile < 0) { 425 ALOGW("Unable to set zygote scheduler boost"); 426 return; 427 } 428 if (boost) { 429 write(schedBoostFile, "100\0", 4); 430 } else { 431 write(schedBoostFile, "0\0", 2); 432 } 433 close(schedBoostFile); 434} 435#endif 436 437// Utility routine to fork zygote and specialize the child process. 438static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray javaGids, 439 jint debug_flags, jobjectArray javaRlimits, 440 jlong permittedCapabilities, jlong effectiveCapabilities, 441 jint mount_external, 442 jstring java_se_info, jstring java_se_name, 443 bool is_system_server, jintArray fdsToClose, 444 jstring instructionSet, jstring dataDir) { 445 SetSigChldHandler(); 446 447#ifdef ENABLE_SCHED_BOOST 448 SetForkLoad(true); 449#endif 450 451 pid_t pid = fork(); 452 453 if (pid == 0) { 454 // The child process. 455 gMallocLeakZygoteChild = 1; 456 457 // Clean up any descriptors which must be closed immediately 458 DetachDescriptors(env, fdsToClose); 459 460 // Keep capabilities across UID change, unless we're staying root. 461 if (uid != 0) { 462 EnableKeepCapabilities(env); 463 } 464 465 DropCapabilitiesBoundingSet(env); 466 467 bool use_native_bridge = !is_system_server && (instructionSet != NULL) 468 && android::NativeBridgeAvailable(); 469 if (use_native_bridge) { 470 ScopedUtfChars isa_string(env, instructionSet); 471 use_native_bridge = android::NeedsNativeBridge(isa_string.c_str()); 472 } 473 if (use_native_bridge && dataDir == NULL) { 474 // dataDir should never be null if we need to use a native bridge. 475 // In general, dataDir will never be null for normal applications. It can only happen in 476 // special cases (for isolated processes which are not associated with any app). These are 477 // launched by the framework and should not be emulated anyway. 478 use_native_bridge = false; 479 ALOGW("Native bridge will not be used because dataDir == NULL."); 480 } 481 482 if (!MountEmulatedStorage(uid, mount_external, use_native_bridge)) { 483 ALOGW("Failed to mount emulated storage: %s", strerror(errno)); 484 if (errno == ENOTCONN || errno == EROFS) { 485 // When device is actively encrypting, we get ENOTCONN here 486 // since FUSE was mounted before the framework restarted. 487 // When encrypted device is booting, we get EROFS since 488 // FUSE hasn't been created yet by init. 489 // In either case, continue without external storage. 490 } else { 491 RuntimeAbort(env, __LINE__, "Cannot continue without emulated storage"); 492 } 493 } 494 495 if (!is_system_server) { 496 int rc = createProcessGroup(uid, getpid()); 497 if (rc != 0) { 498 if (rc == -EROFS) { 499 ALOGW("createProcessGroup failed, kernel missing CONFIG_CGROUP_CPUACCT?"); 500 } else { 501 ALOGE("createProcessGroup(%d, %d) failed: %s", uid, pid, strerror(-rc)); 502 } 503 } 504 } 505 506 SetGids(env, javaGids); 507 508 SetRLimits(env, javaRlimits); 509 510 if (use_native_bridge) { 511 ScopedUtfChars isa_string(env, instructionSet); 512 ScopedUtfChars data_dir(env, dataDir); 513 android::PreInitializeNativeBridge(data_dir.c_str(), isa_string.c_str()); 514 } 515 516 int rc = setresgid(gid, gid, gid); 517 if (rc == -1) { 518 ALOGE("setresgid(%d) failed: %s", gid, strerror(errno)); 519 RuntimeAbort(env, __LINE__, "setresgid failed"); 520 } 521 522 rc = setresuid(uid, uid, uid); 523 if (rc == -1) { 524 ALOGE("setresuid(%d) failed: %s", uid, strerror(errno)); 525 RuntimeAbort(env, __LINE__, "setresuid failed"); 526 } 527 528 if (NeedsNoRandomizeWorkaround()) { 529 // Work around ARM kernel ASLR lossage (http://b/5817320). 530 int old_personality = personality(0xffffffff); 531 int new_personality = personality(old_personality | ADDR_NO_RANDOMIZE); 532 if (new_personality == -1) { 533 ALOGW("personality(%d) failed: %s", new_personality, strerror(errno)); 534 } 535 } 536 537 SetCapabilities(env, permittedCapabilities, effectiveCapabilities); 538 539 SetSchedulerPolicy(env); 540 541 const char* se_info_c_str = NULL; 542 ScopedUtfChars* se_info = NULL; 543 if (java_se_info != NULL) { 544 se_info = new ScopedUtfChars(env, java_se_info); 545 se_info_c_str = se_info->c_str(); 546 if (se_info_c_str == NULL) { 547 RuntimeAbort(env, __LINE__, "se_info_c_str == NULL"); 548 } 549 } 550 const char* se_name_c_str = NULL; 551 ScopedUtfChars* se_name = NULL; 552 if (java_se_name != NULL) { 553 se_name = new ScopedUtfChars(env, java_se_name); 554 se_name_c_str = se_name->c_str(); 555 if (se_name_c_str == NULL) { 556 RuntimeAbort(env, __LINE__, "se_name_c_str == NULL"); 557 } 558 } 559 rc = selinux_android_setcontext(uid, is_system_server, se_info_c_str, se_name_c_str); 560 if (rc == -1) { 561 ALOGE("selinux_android_setcontext(%d, %d, \"%s\", \"%s\") failed", uid, 562 is_system_server, se_info_c_str, se_name_c_str); 563 RuntimeAbort(env, __LINE__, "selinux_android_setcontext failed"); 564 } 565 566 // Make it easier to debug audit logs by setting the main thread's name to the 567 // nice name rather than "app_process". 568 if (se_info_c_str == NULL && is_system_server) { 569 se_name_c_str = "system_server"; 570 } 571 if (se_info_c_str != NULL) { 572 SetThreadName(se_name_c_str); 573 } 574 575 delete se_info; 576 delete se_name; 577 578 UnsetSigChldHandler(); 579 580 env->CallStaticVoidMethod(gZygoteClass, gCallPostForkChildHooks, debug_flags, 581 is_system_server, instructionSet); 582 if (env->ExceptionCheck()) { 583 RuntimeAbort(env, __LINE__, "Error calling post fork hooks."); 584 } 585 } else if (pid > 0) { 586 // the parent process 587 588#ifdef ENABLE_SCHED_BOOST 589 // unset scheduler knob 590 SetForkLoad(false); 591#endif 592 593 } 594 return pid; 595} 596} // anonymous namespace 597 598namespace android { 599 600static jint com_android_internal_os_Zygote_nativeForkAndSpecialize( 601 JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, 602 jint debug_flags, jobjectArray rlimits, 603 jint mount_external, jstring se_info, jstring se_name, 604 jintArray fdsToClose, jstring instructionSet, jstring appDataDir) { 605 jlong capabilities = 0; 606 607 // Grant CAP_WAKE_ALARM to the Bluetooth process. 608 // Additionally, allow bluetooth to open packet sockets so it can start the DHCP client. 609 // TODO: consider making such functionality an RPC to netd. 610 if (multiuser_get_app_id(uid) == AID_BLUETOOTH) { 611 capabilities |= (1LL << CAP_WAKE_ALARM); 612 capabilities |= (1LL << CAP_NET_RAW); 613 capabilities |= (1LL << CAP_NET_BIND_SERVICE); 614 } 615 616 // Grant CAP_BLOCK_SUSPEND to processes that belong to GID "wakelock" 617 bool gid_wakelock_found = false; 618 if (gid == AID_WAKELOCK) { 619 gid_wakelock_found = true; 620 } else if (gids != NULL) { 621 jsize gids_num = env->GetArrayLength(gids); 622 ScopedIntArrayRO ar(env, gids); 623 if (ar.get() == NULL) { 624 RuntimeAbort(env, __LINE__, "Bad gids array"); 625 } 626 for (int i = 0; i < gids_num; i++) { 627 if (ar[i] == AID_WAKELOCK) { 628 gid_wakelock_found = true; 629 break; 630 } 631 } 632 } 633 if (gid_wakelock_found) { 634 capabilities |= (1LL << CAP_BLOCK_SUSPEND); 635 } 636 637 return ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, 638 rlimits, capabilities, capabilities, mount_external, se_info, 639 se_name, false, fdsToClose, instructionSet, appDataDir); 640} 641 642static jint com_android_internal_os_Zygote_nativeForkSystemServer( 643 JNIEnv* env, jclass, uid_t uid, gid_t gid, jintArray gids, 644 jint debug_flags, jobjectArray rlimits, jlong permittedCapabilities, 645 jlong effectiveCapabilities) { 646 pid_t pid = ForkAndSpecializeCommon(env, uid, gid, gids, 647 debug_flags, rlimits, 648 permittedCapabilities, effectiveCapabilities, 649 MOUNT_EXTERNAL_DEFAULT, NULL, NULL, true, NULL, 650 NULL, NULL); 651 if (pid > 0) { 652 // The zygote process checks whether the child process has died or not. 653 ALOGI("System server process %d has been created", pid); 654 gSystemServerPid = pid; 655 // There is a slight window that the system server process has crashed 656 // but it went unnoticed because we haven't published its pid yet. So 657 // we recheck here just to make sure that all is well. 658 int status; 659 if (waitpid(pid, &status, WNOHANG) == pid) { 660 ALOGE("System server process %d has died. Restarting Zygote!", pid); 661 RuntimeAbort(env, __LINE__, "System server process has died. Restarting Zygote!"); 662 } 663 } 664 return pid; 665} 666 667static void com_android_internal_os_Zygote_nativeUnmountStorageOnInit(JNIEnv* env, jclass) { 668 // Zygote process unmount root storage space initially before every child processes are forked. 669 // Every forked child processes (include SystemServer) only mount their own root storage space 670 // And no need unmount storage operation in MountEmulatedStorage method. 671 // Zygote process does not utilize root storage spaces and unshared its mount namespace from the ART. 672 673 UnmountTree("/storage"); 674 return; 675} 676 677static const JNINativeMethod gMethods[] = { 678 { "nativeForkAndSpecialize", 679 "(II[II[[IILjava/lang/String;Ljava/lang/String;[ILjava/lang/String;Ljava/lang/String;)I", 680 (void *) com_android_internal_os_Zygote_nativeForkAndSpecialize }, 681 { "nativeForkSystemServer", "(II[II[[IJJ)I", 682 (void *) com_android_internal_os_Zygote_nativeForkSystemServer }, 683 { "nativeUnmountStorageOnInit", "()V", 684 (void *) com_android_internal_os_Zygote_nativeUnmountStorageOnInit } 685}; 686 687int register_com_android_internal_os_Zygote(JNIEnv* env) { 688 gZygoteClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, kZygoteClassName)); 689 gCallPostForkChildHooks = GetStaticMethodIDOrDie(env, gZygoteClass, "callPostForkChildHooks", 690 "(IZLjava/lang/String;)V"); 691 692 return RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods)); 693} 694} // namespace android 695 696