com_android_internal_os_Zygote.cpp revision c5f27a7cb2ec816f483a65255034a1b57a8aa221
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#include "fd_utils-inl.h" 58 59#include "nativebridge/native_bridge.h" 60 61namespace { 62 63using android::String8; 64 65static pid_t gSystemServerPid = 0; 66 67static const char kZygoteClassName[] = "com/android/internal/os/Zygote"; 68static jclass gZygoteClass; 69static jmethodID gCallPostForkChildHooks; 70 71// Must match values in com.android.internal.os.Zygote. 72enum MountExternalKind { 73 MOUNT_EXTERNAL_NONE = 0, 74 MOUNT_EXTERNAL_DEFAULT = 1, 75 MOUNT_EXTERNAL_READ = 2, 76 MOUNT_EXTERNAL_WRITE = 3, 77}; 78 79static void RuntimeAbort(JNIEnv* env, int line, const char* msg) { 80 std::ostringstream oss; 81 oss << __FILE__ << ":" << line << ": " << msg; 82 env->FatalError(oss.str().c_str()); 83} 84 85// This signal handler is for zygote mode, since the zygote must reap its children 86static void SigChldHandler(int /*signal_number*/) { 87 pid_t pid; 88 int status; 89 90 // It's necessary to save and restore the errno during this function. 91 // Since errno is stored per thread, changing it here modifies the errno 92 // on the thread on which this signal handler executes. If a signal occurs 93 // between a call and an errno check, it's possible to get the errno set 94 // here. 95 // See b/23572286 for extra information. 96 int saved_errno = errno; 97 98 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) { 99 // Log process-death status that we care about. In general it is 100 // not safe to call LOG(...) from a signal handler because of 101 // possible reentrancy. However, we know a priori that the 102 // current implementation of LOG() is safe to call from a SIGCHLD 103 // handler in the zygote process. If the LOG() implementation 104 // changes its locking strategy or its use of syscalls within the 105 // lazy-init critical section, its use here may become unsafe. 106 if (WIFEXITED(status)) { 107 if (WEXITSTATUS(status)) { 108 ALOGI("Process %d exited cleanly (%d)", pid, WEXITSTATUS(status)); 109 } 110 } else if (WIFSIGNALED(status)) { 111 if (WTERMSIG(status) != SIGKILL) { 112 ALOGI("Process %d exited due to signal (%d)", pid, WTERMSIG(status)); 113 } 114 if (WCOREDUMP(status)) { 115 ALOGI("Process %d dumped core.", pid); 116 } 117 } 118 119 // If the just-crashed process is the system_server, bring down zygote 120 // so that it is restarted by init and system server will be restarted 121 // from there. 122 if (pid == gSystemServerPid) { 123 ALOGE("Exit zygote because system server (%d) has terminated", pid); 124 kill(getpid(), SIGKILL); 125 } 126 } 127 128 // Note that we shouldn't consider ECHILD an error because 129 // the secondary zygote might have no children left to wait for. 130 if (pid < 0 && errno != ECHILD) { 131 ALOGW("Zygote SIGCHLD error in waitpid: %s", strerror(errno)); 132 } 133 134 errno = saved_errno; 135} 136 137// Configures the SIGCHLD handler for the zygote process. This is configured 138// very late, because earlier in the runtime we may fork() and exec() 139// other processes, and we want to waitpid() for those rather than 140// have them be harvested immediately. 141// 142// This ends up being called repeatedly before each fork(), but there's 143// no real harm in that. 144static void SetSigChldHandler() { 145 struct sigaction sa; 146 memset(&sa, 0, sizeof(sa)); 147 sa.sa_handler = SigChldHandler; 148 149 int err = sigaction(SIGCHLD, &sa, NULL); 150 if (err < 0) { 151 ALOGW("Error setting SIGCHLD handler: %s", strerror(errno)); 152 } 153} 154 155// Sets the SIGCHLD handler back to default behavior in zygote children. 156static void UnsetSigChldHandler() { 157 struct sigaction sa; 158 memset(&sa, 0, sizeof(sa)); 159 sa.sa_handler = SIG_DFL; 160 161 int err = sigaction(SIGCHLD, &sa, NULL); 162 if (err < 0) { 163 ALOGW("Error unsetting SIGCHLD handler: %s", strerror(errno)); 164 } 165} 166 167// Calls POSIX setgroups() using the int[] object as an argument. 168// A NULL argument is tolerated. 169static void SetGids(JNIEnv* env, jintArray javaGids) { 170 if (javaGids == NULL) { 171 return; 172 } 173 174 ScopedIntArrayRO gids(env, javaGids); 175 if (gids.get() == NULL) { 176 RuntimeAbort(env, __LINE__, "Getting gids int array failed"); 177 } 178 int rc = setgroups(gids.size(), reinterpret_cast<const gid_t*>(&gids[0])); 179 if (rc == -1) { 180 std::ostringstream oss; 181 oss << "setgroups failed: " << strerror(errno) << ", gids.size=" << gids.size(); 182 RuntimeAbort(env, __LINE__, oss.str().c_str()); 183 } 184} 185 186// Sets the resource limits via setrlimit(2) for the values in the 187// two-dimensional array of integers that's passed in. The second dimension 188// contains a tuple of length 3: (resource, rlim_cur, rlim_max). NULL is 189// treated as an empty array. 190static void SetRLimits(JNIEnv* env, jobjectArray javaRlimits) { 191 if (javaRlimits == NULL) { 192 return; 193 } 194 195 rlimit rlim; 196 memset(&rlim, 0, sizeof(rlim)); 197 198 for (int i = 0; i < env->GetArrayLength(javaRlimits); ++i) { 199 ScopedLocalRef<jobject> javaRlimitObject(env, env->GetObjectArrayElement(javaRlimits, i)); 200 ScopedIntArrayRO javaRlimit(env, reinterpret_cast<jintArray>(javaRlimitObject.get())); 201 if (javaRlimit.size() != 3) { 202 RuntimeAbort(env, __LINE__, "rlimits array must have a second dimension of size 3"); 203 } 204 205 rlim.rlim_cur = javaRlimit[1]; 206 rlim.rlim_max = javaRlimit[2]; 207 208 int rc = setrlimit(javaRlimit[0], &rlim); 209 if (rc == -1) { 210 ALOGE("setrlimit(%d, {%ld, %ld}) failed", javaRlimit[0], rlim.rlim_cur, 211 rlim.rlim_max); 212 RuntimeAbort(env, __LINE__, "setrlimit failed"); 213 } 214 } 215} 216 217// The debug malloc library needs to know whether it's the zygote or a child. 218extern "C" int gMallocLeakZygoteChild; 219 220static void EnableKeepCapabilities(JNIEnv* env) { 221 int rc = prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0); 222 if (rc == -1) { 223 RuntimeAbort(env, __LINE__, "prctl(PR_SET_KEEPCAPS) failed"); 224 } 225} 226 227static void DropCapabilitiesBoundingSet(JNIEnv* env) { 228 for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) { 229 int rc = prctl(PR_CAPBSET_DROP, i, 0, 0, 0); 230 if (rc == -1) { 231 if (errno == EINVAL) { 232 ALOGE("prctl(PR_CAPBSET_DROP) failed with EINVAL. Please verify " 233 "your kernel is compiled with file capabilities support"); 234 } else { 235 RuntimeAbort(env, __LINE__, "prctl(PR_CAPBSET_DROP) failed"); 236 } 237 } 238 } 239} 240 241static void SetCapabilities(JNIEnv* env, int64_t permitted, int64_t effective) { 242 __user_cap_header_struct capheader; 243 memset(&capheader, 0, sizeof(capheader)); 244 capheader.version = _LINUX_CAPABILITY_VERSION_3; 245 capheader.pid = 0; 246 247 __user_cap_data_struct capdata[2]; 248 memset(&capdata, 0, sizeof(capdata)); 249 capdata[0].effective = effective; 250 capdata[1].effective = effective >> 32; 251 capdata[0].permitted = permitted; 252 capdata[1].permitted = permitted >> 32; 253 254 if (capset(&capheader, &capdata[0]) == -1) { 255 ALOGE("capset(%" PRId64 ", %" PRId64 ") failed", permitted, effective); 256 RuntimeAbort(env, __LINE__, "capset failed"); 257 } 258} 259 260static void SetSchedulerPolicy(JNIEnv* env) { 261 errno = -set_sched_policy(0, SP_DEFAULT); 262 if (errno != 0) { 263 ALOGE("set_sched_policy(0, SP_DEFAULT) failed"); 264 RuntimeAbort(env, __LINE__, "set_sched_policy(0, SP_DEFAULT) failed"); 265 } 266} 267 268static int UnmountTree(const char* path) { 269 size_t path_len = strlen(path); 270 271 FILE* fp = setmntent("/proc/mounts", "r"); 272 if (fp == NULL) { 273 ALOGE("Error opening /proc/mounts: %s", strerror(errno)); 274 return -errno; 275 } 276 277 // Some volumes can be stacked on each other, so force unmount in 278 // reverse order to give us the best chance of success. 279 std::list<std::string> toUnmount; 280 mntent* mentry; 281 while ((mentry = getmntent(fp)) != NULL) { 282 if (strncmp(mentry->mnt_dir, path, path_len) == 0) { 283 toUnmount.push_front(std::string(mentry->mnt_dir)); 284 } 285 } 286 endmntent(fp); 287 288 for (auto path : toUnmount) { 289 if (umount2(path.c_str(), MNT_DETACH)) { 290 ALOGW("Failed to unmount %s: %s", path.c_str(), strerror(errno)); 291 } 292 } 293 return 0; 294} 295 296// Create a private mount namespace and bind mount appropriate emulated 297// storage for the given user. 298static bool MountEmulatedStorage(uid_t uid, jint mount_mode, 299 bool force_mount_namespace) { 300 // See storage config details at http://source.android.com/tech/storage/ 301 302 // Create a second private mount namespace for our process 303 if (unshare(CLONE_NEWNS) == -1) { 304 ALOGW("Failed to unshare(): %s", strerror(errno)); 305 return false; 306 } 307 308 String8 storageSource; 309 if (mount_mode == MOUNT_EXTERNAL_DEFAULT) { 310 storageSource = "/mnt/runtime/default"; 311 } else if (mount_mode == MOUNT_EXTERNAL_READ) { 312 storageSource = "/mnt/runtime/read"; 313 } else if (mount_mode == MOUNT_EXTERNAL_WRITE) { 314 storageSource = "/mnt/runtime/write"; 315 } else { 316 // Sane default of no storage visible 317 return true; 318 } 319 if (TEMP_FAILURE_RETRY(mount(storageSource.string(), "/storage", 320 NULL, MS_BIND | MS_REC | MS_SLAVE, NULL)) == -1) { 321 ALOGW("Failed to mount %s to /storage: %s", storageSource.string(), strerror(errno)); 322 return false; 323 } 324 325 // Mount user-specific symlink helper into place 326 userid_t user_id = multiuser_get_user_id(uid); 327 const String8 userSource(String8::format("/mnt/user/%d", user_id)); 328 if (fs_prepare_dir(userSource.string(), 0751, 0, 0) == -1) { 329 return false; 330 } 331 if (TEMP_FAILURE_RETRY(mount(userSource.string(), "/storage/self", 332 NULL, MS_BIND, NULL)) == -1) { 333 ALOGW("Failed to mount %s to /storage/self: %s", userSource.string(), strerror(errno)); 334 return false; 335 } 336 337 return true; 338} 339 340static bool NeedsNoRandomizeWorkaround() { 341#if !defined(__arm__) 342 return false; 343#else 344 int major; 345 int minor; 346 struct utsname uts; 347 if (uname(&uts) == -1) { 348 return false; 349 } 350 351 if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) { 352 return false; 353 } 354 355 // Kernels before 3.4.* need the workaround. 356 return (major < 3) || ((major == 3) && (minor < 4)); 357#endif 358} 359 360// Utility to close down the Zygote socket file descriptors while 361// the child is still running as root with Zygote's privileges. Each 362// descriptor (if any) is closed via dup2(), replacing it with a valid 363// (open) descriptor to /dev/null. 364 365static void DetachDescriptors(JNIEnv* env, jintArray fdsToClose) { 366 if (!fdsToClose) { 367 return; 368 } 369 jsize count = env->GetArrayLength(fdsToClose); 370 ScopedIntArrayRO ar(env, fdsToClose); 371 if (ar.get() == NULL) { 372 RuntimeAbort(env, __LINE__, "Bad fd array"); 373 } 374 jsize i; 375 int devnull; 376 for (i = 0; i < count; i++) { 377 devnull = open("/dev/null", O_RDWR); 378 if (devnull < 0) { 379 ALOGE("Failed to open /dev/null: %s", strerror(errno)); 380 RuntimeAbort(env, __LINE__, "Failed to open /dev/null"); 381 continue; 382 } 383 ALOGV("Switching descriptor %d to /dev/null: %s", ar[i], strerror(errno)); 384 if (dup2(devnull, ar[i]) < 0) { 385 ALOGE("Failed dup2() on descriptor %d: %s", ar[i], strerror(errno)); 386 RuntimeAbort(env, __LINE__, "Failed dup2()"); 387 } 388 close(devnull); 389 } 390} 391 392void SetThreadName(const char* thread_name) { 393 bool hasAt = false; 394 bool hasDot = false; 395 const char* s = thread_name; 396 while (*s) { 397 if (*s == '.') { 398 hasDot = true; 399 } else if (*s == '@') { 400 hasAt = true; 401 } 402 s++; 403 } 404 const int len = s - thread_name; 405 if (len < 15 || hasAt || !hasDot) { 406 s = thread_name; 407 } else { 408 s = thread_name + len - 15; 409 } 410 // pthread_setname_np fails rather than truncating long strings. 411 char buf[16]; // MAX_TASK_COMM_LEN=16 is hard-coded into bionic 412 strlcpy(buf, s, sizeof(buf)-1); 413 errno = pthread_setname_np(pthread_self(), buf); 414 if (errno != 0) { 415 ALOGW("Unable to set the name of current thread to '%s': %s", buf, strerror(errno)); 416 } 417} 418 419#ifdef ENABLE_SCHED_BOOST 420static void SetForkLoad(bool boost) { 421 // set scheduler knob to boost forked processes 422 pid_t currentPid = getpid(); 423 // fits at most "/proc/XXXXXXX/sched_init_task_load\0" 424 char schedPath[35]; 425 snprintf(schedPath, sizeof(schedPath), "/proc/%u/sched_init_task_load", currentPid); 426 int schedBoostFile = open(schedPath, O_WRONLY); 427 if (schedBoostFile < 0) { 428 ALOGW("Unable to set zygote scheduler boost"); 429 return; 430 } 431 if (boost) { 432 write(schedBoostFile, "100\0", 4); 433 } else { 434 write(schedBoostFile, "0\0", 2); 435 } 436 close(schedBoostFile); 437} 438#endif 439 440// The list of open zygote file descriptors. 441static FileDescriptorTable* gOpenFdTable = NULL; 442 443// Utility routine to fork zygote and specialize the child process. 444static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray javaGids, 445 jint debug_flags, jobjectArray javaRlimits, 446 jlong permittedCapabilities, jlong effectiveCapabilities, 447 jint mount_external, 448 jstring java_se_info, jstring java_se_name, 449 bool is_system_server, jintArray fdsToClose, 450 jstring instructionSet, jstring dataDir) { 451 SetSigChldHandler(); 452 453#ifdef ENABLE_SCHED_BOOST 454 SetForkLoad(true); 455#endif 456 457 // If this is the first fork for this zygote, create the open FD table. 458 // If it isn't, we just need to check whether the list of open files has 459 // changed (and it shouldn't in the normal case). 460 if (gOpenFdTable == NULL) { 461 gOpenFdTable = FileDescriptorTable::Create(); 462 if (gOpenFdTable == NULL) { 463 RuntimeAbort(env, __LINE__, "Unable to construct file descriptor table."); 464 } 465 } else if (!gOpenFdTable->Restat()) { 466 RuntimeAbort(env, __LINE__, "Unable to restat file descriptor table."); 467 } 468 469 pid_t pid = fork(); 470 471 if (pid == 0) { 472 // The child process. 473 gMallocLeakZygoteChild = 1; 474 475 // Clean up any descriptors which must be closed immediately 476 DetachDescriptors(env, fdsToClose); 477 478 // Re-open all remaining open file descriptors so that they aren't shared 479 // with the zygote across a fork. 480 if (!gOpenFdTable->Reopen()) { 481 RuntimeAbort(env, __LINE__, "Unable to reopen whitelisted descriptors."); 482 } 483 484 // Keep capabilities across UID change, unless we're staying root. 485 if (uid != 0) { 486 EnableKeepCapabilities(env); 487 } 488 489 DropCapabilitiesBoundingSet(env); 490 491 bool use_native_bridge = !is_system_server && (instructionSet != NULL) 492 && android::NativeBridgeAvailable(); 493 if (use_native_bridge) { 494 ScopedUtfChars isa_string(env, instructionSet); 495 use_native_bridge = android::NeedsNativeBridge(isa_string.c_str()); 496 } 497 if (use_native_bridge && dataDir == NULL) { 498 // dataDir should never be null if we need to use a native bridge. 499 // In general, dataDir will never be null for normal applications. It can only happen in 500 // special cases (for isolated processes which are not associated with any app). These are 501 // launched by the framework and should not be emulated anyway. 502 use_native_bridge = false; 503 ALOGW("Native bridge will not be used because dataDir == NULL."); 504 } 505 506 if (!MountEmulatedStorage(uid, mount_external, use_native_bridge)) { 507 ALOGW("Failed to mount emulated storage: %s", strerror(errno)); 508 if (errno == ENOTCONN || errno == EROFS) { 509 // When device is actively encrypting, we get ENOTCONN here 510 // since FUSE was mounted before the framework restarted. 511 // When encrypted device is booting, we get EROFS since 512 // FUSE hasn't been created yet by init. 513 // In either case, continue without external storage. 514 } else { 515 RuntimeAbort(env, __LINE__, "Cannot continue without emulated storage"); 516 } 517 } 518 519 if (!is_system_server) { 520 int rc = createProcessGroup(uid, getpid()); 521 if (rc != 0) { 522 if (rc == -EROFS) { 523 ALOGW("createProcessGroup failed, kernel missing CONFIG_CGROUP_CPUACCT?"); 524 } else { 525 ALOGE("createProcessGroup(%d, %d) failed: %s", uid, pid, strerror(-rc)); 526 } 527 } 528 } 529 530 SetGids(env, javaGids); 531 532 SetRLimits(env, javaRlimits); 533 534 if (use_native_bridge) { 535 ScopedUtfChars isa_string(env, instructionSet); 536 ScopedUtfChars data_dir(env, dataDir); 537 android::PreInitializeNativeBridge(data_dir.c_str(), isa_string.c_str()); 538 } 539 540 int rc = setresgid(gid, gid, gid); 541 if (rc == -1) { 542 ALOGE("setresgid(%d) failed: %s", gid, strerror(errno)); 543 RuntimeAbort(env, __LINE__, "setresgid failed"); 544 } 545 546 rc = setresuid(uid, uid, uid); 547 if (rc == -1) { 548 ALOGE("setresuid(%d) failed: %s", uid, strerror(errno)); 549 RuntimeAbort(env, __LINE__, "setresuid failed"); 550 } 551 552 if (NeedsNoRandomizeWorkaround()) { 553 // Work around ARM kernel ASLR lossage (http://b/5817320). 554 int old_personality = personality(0xffffffff); 555 int new_personality = personality(old_personality | ADDR_NO_RANDOMIZE); 556 if (new_personality == -1) { 557 ALOGW("personality(%d) failed: %s", new_personality, strerror(errno)); 558 } 559 } 560 561 SetCapabilities(env, permittedCapabilities, effectiveCapabilities); 562 563 SetSchedulerPolicy(env); 564 565 const char* se_info_c_str = NULL; 566 ScopedUtfChars* se_info = NULL; 567 if (java_se_info != NULL) { 568 se_info = new ScopedUtfChars(env, java_se_info); 569 se_info_c_str = se_info->c_str(); 570 if (se_info_c_str == NULL) { 571 RuntimeAbort(env, __LINE__, "se_info_c_str == NULL"); 572 } 573 } 574 const char* se_name_c_str = NULL; 575 ScopedUtfChars* se_name = NULL; 576 if (java_se_name != NULL) { 577 se_name = new ScopedUtfChars(env, java_se_name); 578 se_name_c_str = se_name->c_str(); 579 if (se_name_c_str == NULL) { 580 RuntimeAbort(env, __LINE__, "se_name_c_str == NULL"); 581 } 582 } 583 rc = selinux_android_setcontext(uid, is_system_server, se_info_c_str, se_name_c_str); 584 if (rc == -1) { 585 ALOGE("selinux_android_setcontext(%d, %d, \"%s\", \"%s\") failed", uid, 586 is_system_server, se_info_c_str, se_name_c_str); 587 RuntimeAbort(env, __LINE__, "selinux_android_setcontext failed"); 588 } 589 590 // Make it easier to debug audit logs by setting the main thread's name to the 591 // nice name rather than "app_process". 592 if (se_info_c_str == NULL && is_system_server) { 593 se_name_c_str = "system_server"; 594 } 595 if (se_info_c_str != NULL) { 596 SetThreadName(se_name_c_str); 597 } 598 599 delete se_info; 600 delete se_name; 601 602 UnsetSigChldHandler(); 603 604 env->CallStaticVoidMethod(gZygoteClass, gCallPostForkChildHooks, debug_flags, 605 is_system_server, instructionSet); 606 if (env->ExceptionCheck()) { 607 RuntimeAbort(env, __LINE__, "Error calling post fork hooks."); 608 } 609 } else if (pid > 0) { 610 // the parent process 611 612#ifdef ENABLE_SCHED_BOOST 613 // unset scheduler knob 614 SetForkLoad(false); 615#endif 616 617 } 618 return pid; 619} 620} // anonymous namespace 621 622namespace android { 623 624static jint com_android_internal_os_Zygote_nativeForkAndSpecialize( 625 JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, 626 jint debug_flags, jobjectArray rlimits, 627 jint mount_external, jstring se_info, jstring se_name, 628 jintArray fdsToClose, jstring instructionSet, jstring appDataDir) { 629 jlong capabilities = 0; 630 631 // Grant CAP_WAKE_ALARM to the Bluetooth process. 632 // Additionally, allow bluetooth to open packet sockets so it can start the DHCP client. 633 // TODO: consider making such functionality an RPC to netd. 634 if (multiuser_get_app_id(uid) == AID_BLUETOOTH) { 635 capabilities |= (1LL << CAP_WAKE_ALARM); 636 capabilities |= (1LL << CAP_NET_RAW); 637 capabilities |= (1LL << CAP_NET_BIND_SERVICE); 638 } 639 640 // Grant CAP_BLOCK_SUSPEND to processes that belong to GID "wakelock" 641 bool gid_wakelock_found = false; 642 if (gid == AID_WAKELOCK) { 643 gid_wakelock_found = true; 644 } else if (gids != NULL) { 645 jsize gids_num = env->GetArrayLength(gids); 646 ScopedIntArrayRO ar(env, gids); 647 if (ar.get() == NULL) { 648 RuntimeAbort(env, __LINE__, "Bad gids array"); 649 } 650 for (int i = 0; i < gids_num; i++) { 651 if (ar[i] == AID_WAKELOCK) { 652 gid_wakelock_found = true; 653 break; 654 } 655 } 656 } 657 if (gid_wakelock_found) { 658 capabilities |= (1LL << CAP_BLOCK_SUSPEND); 659 } 660 661 return ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, 662 rlimits, capabilities, capabilities, mount_external, se_info, 663 se_name, false, fdsToClose, instructionSet, appDataDir); 664} 665 666static jint com_android_internal_os_Zygote_nativeForkSystemServer( 667 JNIEnv* env, jclass, uid_t uid, gid_t gid, jintArray gids, 668 jint debug_flags, jobjectArray rlimits, jlong permittedCapabilities, 669 jlong effectiveCapabilities) { 670 pid_t pid = ForkAndSpecializeCommon(env, uid, gid, gids, 671 debug_flags, rlimits, 672 permittedCapabilities, effectiveCapabilities, 673 MOUNT_EXTERNAL_DEFAULT, NULL, NULL, true, NULL, 674 NULL, NULL); 675 if (pid > 0) { 676 // The zygote process checks whether the child process has died or not. 677 ALOGI("System server process %d has been created", pid); 678 gSystemServerPid = pid; 679 // There is a slight window that the system server process has crashed 680 // but it went unnoticed because we haven't published its pid yet. So 681 // we recheck here just to make sure that all is well. 682 int status; 683 if (waitpid(pid, &status, WNOHANG) == pid) { 684 ALOGE("System server process %d has died. Restarting Zygote!", pid); 685 RuntimeAbort(env, __LINE__, "System server process has died. Restarting Zygote!"); 686 } 687 } 688 return pid; 689} 690 691static void com_android_internal_os_Zygote_nativeUnmountStorageOnInit(JNIEnv* env, jclass) { 692 // Zygote process unmount root storage space initially before every child processes are forked. 693 // Every forked child processes (include SystemServer) only mount their own root storage space 694 // And no need unmount storage operation in MountEmulatedStorage method. 695 // Zygote process does not utilize root storage spaces and unshared its mount namespace from the ART. 696 697 UnmountTree("/storage"); 698 return; 699} 700 701static const JNINativeMethod gMethods[] = { 702 { "nativeForkAndSpecialize", 703 "(II[II[[IILjava/lang/String;Ljava/lang/String;[ILjava/lang/String;Ljava/lang/String;)I", 704 (void *) com_android_internal_os_Zygote_nativeForkAndSpecialize }, 705 { "nativeForkSystemServer", "(II[II[[IJJ)I", 706 (void *) com_android_internal_os_Zygote_nativeForkSystemServer }, 707 { "nativeUnmountStorageOnInit", "()V", 708 (void *) com_android_internal_os_Zygote_nativeUnmountStorageOnInit } 709}; 710 711int register_com_android_internal_os_Zygote(JNIEnv* env) { 712 gZygoteClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, kZygoteClassName)); 713 gCallPostForkChildHooks = GetStaticMethodIDOrDie(env, gZygoteClass, "callPostForkChildHooks", 714 "(IZLjava/lang/String;)V"); 715 716 return RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods)); 717} 718} // namespace android 719 720