| /* |
| * Copyright (C) 2008 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. |
| */ |
| |
| // sys/mount.h has to come before linux/fs.h due to redefinition of MS_RDONLY, MS_BIND, etc |
| #include <sys/mount.h> |
| #include <linux/fs.h> |
| |
| #include <grp.h> |
| #include <paths.h> |
| #include <signal.h> |
| #include <stdlib.h> |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| #include <unistd.h> |
| |
| #include "cutils/fs.h" |
| #include "cutils/multiuser.h" |
| #include "cutils/sched_policy.h" |
| #include "debugger.h" |
| #include "jni_internal.h" |
| #include "JNIHelp.h" |
| #include "ScopedLocalRef.h" |
| #include "ScopedPrimitiveArray.h" |
| #include "ScopedUtfChars.h" |
| #include "thread-inl.h" |
| #include "utils.h" |
| |
| #if defined(HAVE_PRCTL) |
| #include <sys/prctl.h> |
| #endif |
| |
| #include <selinux/android.h> |
| |
| #if defined(__linux__) |
| #include <sys/personality.h> |
| #include <sys/utsname.h> |
| #include <sys/capability.h> |
| #endif |
| |
| namespace art { |
| |
| static pid_t gSystemServerPid = 0; |
| |
| // Must match values in dalvik.system.Zygote. |
| enum MountExternalKind { |
| MOUNT_EXTERNAL_NONE = 0, |
| MOUNT_EXTERNAL_SINGLEUSER = 1, |
| MOUNT_EXTERNAL_MULTIUSER = 2, |
| MOUNT_EXTERNAL_MULTIUSER_ALL = 3, |
| }; |
| |
| // This signal handler is for zygote mode, since the zygote must reap its children |
| static void SigChldHandler(int /*signal_number*/) { |
| pid_t pid; |
| int status; |
| |
| while ((pid = waitpid(-1, &status, WNOHANG)) > 0) { |
| // Log process-death status that we care about. In general it is |
| // not safe to call LOG(...) from a signal handler because of |
| // possible reentrancy. However, we know a priori that the |
| // current implementation of LOG() is safe to call from a SIGCHLD |
| // handler in the zygote process. If the LOG() implementation |
| // changes its locking strategy or its use of syscalls within the |
| // lazy-init critical section, its use here may become unsafe. |
| if (WIFEXITED(status)) { |
| if (WEXITSTATUS(status)) { |
| LOG(INFO) << "Process " << pid << " exited cleanly (" << WEXITSTATUS(status) << ")"; |
| } else if (false) { |
| LOG(INFO) << "Process " << pid << " exited cleanly (" << WEXITSTATUS(status) << ")"; |
| } |
| } else if (WIFSIGNALED(status)) { |
| if (WTERMSIG(status) != SIGKILL) { |
| LOG(INFO) << "Process " << pid << " terminated by signal (" << WTERMSIG(status) << ")"; |
| } else if (false) { |
| LOG(INFO) << "Process " << pid << " terminated by signal (" << WTERMSIG(status) << ")"; |
| } |
| #ifdef WCOREDUMP |
| if (WCOREDUMP(status)) { |
| LOG(INFO) << "Process " << pid << " dumped core"; |
| } |
| #endif /* ifdef WCOREDUMP */ |
| } |
| |
| // If the just-crashed process is the system_server, bring down zygote |
| // so that it is restarted by init and system server will be restarted |
| // from there. |
| if (pid == gSystemServerPid) { |
| LOG(ERROR) << "Exit zygote because system server (" << pid << ") has terminated"; |
| kill(getpid(), SIGKILL); |
| } |
| } |
| |
| if (pid < 0) { |
| PLOG(WARNING) << "Zygote SIGCHLD error in waitpid"; |
| } |
| } |
| |
| // Configures the SIGCHLD handler for the zygote process. This is configured |
| // very late, because earlier in the runtime we may fork() and exec() |
| // other processes, and we want to waitpid() for those rather than |
| // have them be harvested immediately. |
| // |
| // This ends up being called repeatedly before each fork(), but there's |
| // no real harm in that. |
| static void SetSigChldHandler() { |
| struct sigaction sa; |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_handler = SigChldHandler; |
| |
| int err = sigaction(SIGCHLD, &sa, NULL); |
| if (err < 0) { |
| PLOG(WARNING) << "Error setting SIGCHLD handler"; |
| } |
| } |
| |
| // Sets the SIGCHLD handler back to default behavior in zygote children. |
| static void UnsetSigChldHandler() { |
| struct sigaction sa; |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_handler = SIG_DFL; |
| |
| int err = sigaction(SIGCHLD, &sa, NULL); |
| if (err < 0) { |
| PLOG(WARNING) << "Error unsetting SIGCHLD handler"; |
| } |
| } |
| |
| // Calls POSIX setgroups() using the int[] object as an argument. |
| // A NULL argument is tolerated. |
| static void SetGids(JNIEnv* env, jintArray javaGids) { |
| if (javaGids == NULL) { |
| return; |
| } |
| |
| COMPILE_ASSERT(sizeof(gid_t) == sizeof(jint), sizeof_gid_and_jint_are_differerent); |
| ScopedIntArrayRO gids(env, javaGids); |
| CHECK(gids.get() != NULL); |
| int rc = setgroups(gids.size(), reinterpret_cast<const gid_t*>(&gids[0])); |
| if (rc == -1) { |
| PLOG(FATAL) << "setgroups failed"; |
| } |
| } |
| |
| // Sets the resource limits via setrlimit(2) for the values in the |
| // two-dimensional array of integers that's passed in. The second dimension |
| // contains a tuple of length 3: (resource, rlim_cur, rlim_max). NULL is |
| // treated as an empty array. |
| static void SetRLimits(JNIEnv* env, jobjectArray javaRlimits) { |
| if (javaRlimits == NULL) { |
| return; |
| } |
| |
| rlimit rlim; |
| memset(&rlim, 0, sizeof(rlim)); |
| |
| for (int i = 0; i < env->GetArrayLength(javaRlimits); ++i) { |
| ScopedLocalRef<jobject> javaRlimitObject(env, env->GetObjectArrayElement(javaRlimits, i)); |
| ScopedIntArrayRO javaRlimit(env, reinterpret_cast<jintArray>(javaRlimitObject.get())); |
| if (javaRlimit.size() != 3) { |
| LOG(FATAL) << "rlimits array must have a second dimension of size 3"; |
| } |
| |
| rlim.rlim_cur = javaRlimit[1]; |
| rlim.rlim_max = javaRlimit[2]; |
| |
| int rc = setrlimit(javaRlimit[0], &rlim); |
| if (rc == -1) { |
| PLOG(FATAL) << "setrlimit(" << javaRlimit[0] << ", " |
| << "{" << rlim.rlim_cur << ", " << rlim.rlim_max << "}) failed"; |
| } |
| } |
| } |
| |
| #if defined(HAVE_ANDROID_OS) |
| |
| // The debug malloc library needs to know whether it's the zygote or a child. |
| extern "C" int gMallocLeakZygoteChild; |
| |
| static void EnableDebugger() { |
| // To let a non-privileged gdbserver attach to this |
| // process, we must set our dumpable flag. |
| if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) { |
| PLOG(ERROR) << "prctl(PR_SET_DUMPABLE) failed for pid " << getpid(); |
| } |
| // We don't want core dumps, though, so set the core dump size to 0. |
| rlimit rl; |
| rl.rlim_cur = 0; |
| rl.rlim_max = RLIM_INFINITY; |
| if (setrlimit(RLIMIT_CORE, &rl) == -1) { |
| PLOG(ERROR) << "setrlimit(RLIMIT_CORE) failed for pid " << getpid(); |
| } |
| } |
| |
| static void EnableKeepCapabilities() { |
| int rc = prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0); |
| if (rc == -1) { |
| PLOG(FATAL) << "prctl(PR_SET_KEEPCAPS) failed"; |
| } |
| } |
| |
| static void DropCapabilitiesBoundingSet() { |
| for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) { |
| if (i == CAP_NET_RAW) { |
| // Don't break /system/bin/ping |
| continue; |
| } |
| int rc = prctl(PR_CAPBSET_DROP, i, 0, 0, 0); |
| if (rc == -1) { |
| if (errno == EINVAL) { |
| PLOG(ERROR) << "prctl(PR_CAPBSET_DROP) failed with EINVAL. Please verify " |
| << "your kernel is compiled with file capabilities support"; |
| } else { |
| PLOG(FATAL) << "prctl(PR_CAPBSET_DROP) failed"; |
| } |
| } |
| } |
| } |
| |
| static void SetCapabilities(int64_t permitted, int64_t effective) { |
| __user_cap_header_struct capheader; |
| memset(&capheader, 0, sizeof(capheader)); |
| capheader.version = _LINUX_CAPABILITY_VERSION_3; |
| capheader.pid = 0; |
| |
| __user_cap_data_struct capdata[2]; |
| memset(&capdata, 0, sizeof(capdata)); |
| capdata[0].effective = effective; |
| capdata[1].effective = effective >> 32; |
| capdata[0].permitted = permitted; |
| capdata[1].permitted = permitted >> 32; |
| |
| if (capset(&capheader, &capdata[0]) == -1) { |
| PLOG(FATAL) << "capset(" << permitted << ", " << effective << ") failed"; |
| } |
| } |
| |
| static void SetSchedulerPolicy() { |
| errno = -set_sched_policy(0, SP_DEFAULT); |
| if (errno != 0) { |
| PLOG(FATAL) << "set_sched_policy(0, SP_DEFAULT) failed"; |
| } |
| } |
| |
| #else |
| |
| static int gMallocLeakZygoteChild = 0; |
| |
| static void EnableDebugger() {} |
| static void EnableKeepCapabilities() {} |
| static void DropCapabilitiesBoundingSet() {} |
| static void SetCapabilities(int64_t, int64_t) {} |
| static void SetSchedulerPolicy() {} |
| |
| #endif |
| |
| static void EnableDebugFeatures(uint32_t debug_flags) { |
| // Must match values in dalvik.system.Zygote. |
| enum { |
| DEBUG_ENABLE_DEBUGGER = 1, |
| DEBUG_ENABLE_CHECKJNI = 1 << 1, |
| DEBUG_ENABLE_ASSERT = 1 << 2, |
| DEBUG_ENABLE_SAFEMODE = 1 << 3, |
| DEBUG_ENABLE_JNI_LOGGING = 1 << 4, |
| }; |
| |
| if ((debug_flags & DEBUG_ENABLE_CHECKJNI) != 0) { |
| Runtime* runtime = Runtime::Current(); |
| JavaVMExt* vm = runtime->GetJavaVM(); |
| if (!vm->check_jni) { |
| LOG(DEBUG) << "Late-enabling -Xcheck:jni"; |
| vm->SetCheckJniEnabled(true); |
| // There's only one thread running at this point, so only one JNIEnv to fix up. |
| Thread::Current()->GetJniEnv()->SetCheckJniEnabled(true); |
| } else { |
| LOG(DEBUG) << "Not late-enabling -Xcheck:jni (already on)"; |
| } |
| debug_flags &= ~DEBUG_ENABLE_CHECKJNI; |
| } |
| |
| if ((debug_flags & DEBUG_ENABLE_JNI_LOGGING) != 0) { |
| gLogVerbosity.third_party_jni = true; |
| debug_flags &= ~DEBUG_ENABLE_JNI_LOGGING; |
| } |
| |
| Dbg::SetJdwpAllowed((debug_flags & DEBUG_ENABLE_DEBUGGER) != 0); |
| if ((debug_flags & DEBUG_ENABLE_DEBUGGER) != 0) { |
| EnableDebugger(); |
| } |
| debug_flags &= ~DEBUG_ENABLE_DEBUGGER; |
| |
| // These two are for backwards compatibility with Dalvik. |
| debug_flags &= ~DEBUG_ENABLE_ASSERT; |
| debug_flags &= ~DEBUG_ENABLE_SAFEMODE; |
| |
| if (debug_flags != 0) { |
| LOG(ERROR) << StringPrintf("Unknown bits set in debug_flags: %#x", debug_flags); |
| } |
| } |
| |
| // Create a private mount namespace and bind mount appropriate emulated |
| // storage for the given user. |
| static bool MountEmulatedStorage(uid_t uid, jint mount_mode) { |
| if (mount_mode == MOUNT_EXTERNAL_NONE) { |
| return true; |
| } |
| |
| // See storage config details at http://source.android.com/tech/storage/ |
| userid_t user_id = multiuser_get_user_id(uid); |
| |
| // Create a second private mount namespace for our process |
| if (unshare(CLONE_NEWNS) == -1) { |
| PLOG(WARNING) << "Failed to unshare()"; |
| return false; |
| } |
| |
| // Create bind mounts to expose external storage |
| if (mount_mode == MOUNT_EXTERNAL_MULTIUSER || mount_mode == MOUNT_EXTERNAL_MULTIUSER_ALL) { |
| // These paths must already be created by init.rc |
| const char* source = getenv("EMULATED_STORAGE_SOURCE"); |
| const char* target = getenv("EMULATED_STORAGE_TARGET"); |
| const char* legacy = getenv("EXTERNAL_STORAGE"); |
| if (source == NULL || target == NULL || legacy == NULL) { |
| LOG(WARNING) << "Storage environment undefined; unable to provide external storage"; |
| return false; |
| } |
| |
| // Prepare source paths |
| |
| // /mnt/shell/emulated/0 |
| std::string source_user(StringPrintf("%s/%d", source, user_id)); |
| // /storage/emulated/0 |
| std::string target_user(StringPrintf("%s/%d", target, user_id)); |
| |
| if (fs_prepare_dir(source_user.c_str(), 0000, 0, 0) == -1 |
| || fs_prepare_dir(target_user.c_str(), 0000, 0, 0) == -1) { |
| return false; |
| } |
| |
| if (mount_mode == MOUNT_EXTERNAL_MULTIUSER_ALL) { |
| // Mount entire external storage tree for all users |
| if (mount(source, target, NULL, MS_BIND, NULL) == -1) { |
| PLOG(WARNING) << "Failed to mount " << source << " to " << target; |
| return false; |
| } |
| } else { |
| // Only mount user-specific external storage |
| if (mount(source_user.c_str(), target_user.c_str(), NULL, MS_BIND, NULL) == -1) { |
| PLOG(WARNING) << "Failed to mount " << source_user << " to " << target_user; |
| return false; |
| } |
| } |
| |
| if (fs_prepare_dir(legacy, 0000, 0, 0) == -1) { |
| return false; |
| } |
| |
| // Finally, mount user-specific path into place for legacy users |
| if (mount(target_user.c_str(), legacy, NULL, MS_BIND | MS_REC, NULL) == -1) { |
| PLOG(WARNING) << "Failed to mount " << target_user << " to " << legacy; |
| return false; |
| } |
| } else { |
| LOG(WARNING) << "Mount mode " << mount_mode << " unsupported"; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| #if defined(__linux__) |
| static bool NeedsNoRandomizeWorkaround() { |
| #if !defined(__arm__) |
| return false; |
| #else |
| int major; |
| int minor; |
| struct utsname uts; |
| if (uname(&uts) == -1) { |
| return false; |
| } |
| |
| if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) { |
| return false; |
| } |
| |
| // Kernels before 3.4.* need the workaround. |
| return (major < 3) || ((major == 3) && (minor < 4)); |
| #endif |
| } |
| #endif |
| |
| // Utility routine to fork zygote and specialize the child process. |
| static pid_t ForkAndSpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray javaGids, |
| jint debug_flags, jobjectArray javaRlimits, |
| jlong permittedCapabilities, jlong effectiveCapabilities, |
| jint mount_external, |
| jstring java_se_info, jstring java_se_name, bool is_system_server) { |
| Runtime* runtime = Runtime::Current(); |
| CHECK(runtime->IsZygote()) << "runtime instance not started with -Xzygote"; |
| if (!runtime->PreZygoteFork()) { |
| LOG(FATAL) << "pre-fork heap failed"; |
| } |
| |
| SetSigChldHandler(); |
| |
| // Grab thread before fork potentially makes Thread::pthread_key_self_ unusable. |
| Thread* self = Thread::Current(); |
| |
| // dvmDumpLoaderStats("zygote"); // TODO: ? |
| pid_t pid = fork(); |
| |
| if (pid == 0) { |
| // The child process. |
| gMallocLeakZygoteChild = 1; |
| |
| // Keep capabilities across UID change, unless we're staying root. |
| if (uid != 0) { |
| EnableKeepCapabilities(); |
| } |
| |
| DropCapabilitiesBoundingSet(); |
| |
| if (!MountEmulatedStorage(uid, mount_external)) { |
| PLOG(WARNING) << "Failed to mount emulated storage"; |
| if (errno == ENOTCONN || errno == EROFS) { |
| // When device is actively encrypting, we get ENOTCONN here |
| // since FUSE was mounted before the framework restarted. |
| // When encrypted device is booting, we get EROFS since |
| // FUSE hasn't been created yet by init. |
| // In either case, continue without external storage. |
| } else { |
| LOG(FATAL) << "Cannot continue without emulated storage"; |
| } |
| } |
| |
| SetGids(env, javaGids); |
| |
| SetRLimits(env, javaRlimits); |
| |
| int rc = setresgid(gid, gid, gid); |
| if (rc == -1) { |
| PLOG(FATAL) << "setresgid(" << gid << ") failed"; |
| } |
| |
| rc = setresuid(uid, uid, uid); |
| if (rc == -1) { |
| PLOG(FATAL) << "setresuid(" << uid << ") failed"; |
| } |
| |
| #if defined(__linux__) |
| if (NeedsNoRandomizeWorkaround()) { |
| // Work around ARM kernel ASLR lossage (http://b/5817320). |
| int old_personality = personality(0xffffffff); |
| int new_personality = personality(old_personality | ADDR_NO_RANDOMIZE); |
| if (new_personality == -1) { |
| PLOG(WARNING) << "personality(" << new_personality << ") failed"; |
| } |
| } |
| #endif |
| |
| SetCapabilities(permittedCapabilities, effectiveCapabilities); |
| |
| SetSchedulerPolicy(); |
| |
| #if defined(HAVE_ANDROID_OS) |
| { // NOLINT(whitespace/braces) |
| const char* se_info_c_str = NULL; |
| UniquePtr<ScopedUtfChars> se_info; |
| if (java_se_info != NULL) { |
| se_info.reset(new ScopedUtfChars(env, java_se_info)); |
| se_info_c_str = se_info->c_str(); |
| CHECK(se_info_c_str != NULL); |
| } |
| const char* se_name_c_str = NULL; |
| UniquePtr<ScopedUtfChars> se_name; |
| if (java_se_name != NULL) { |
| se_name.reset(new ScopedUtfChars(env, java_se_name)); |
| se_name_c_str = se_name->c_str(); |
| CHECK(se_name_c_str != NULL); |
| } |
| rc = selinux_android_setcontext(uid, is_system_server, se_info_c_str, se_name_c_str); |
| if (rc == -1) { |
| PLOG(FATAL) << "selinux_android_setcontext(" << uid << ", " |
| << (is_system_server ? "true" : "false") << ", " |
| << "\"" << se_info_c_str << "\", \"" << se_name_c_str << "\") failed"; |
| } |
| |
| // Make it easier to debug audit logs by setting the main thread's name to the |
| // nice name rather than "app_process". |
| if (se_info_c_str == NULL && is_system_server) { |
| se_name_c_str = "system_server"; |
| } |
| if (se_info_c_str != NULL) { |
| SetThreadName(se_name_c_str); |
| } |
| } |
| #else |
| UNUSED(is_system_server); |
| UNUSED(java_se_info); |
| UNUSED(java_se_name); |
| #endif |
| |
| // Our system thread ID, etc, has changed so reset Thread state. |
| self->InitAfterFork(); |
| |
| EnableDebugFeatures(debug_flags); |
| |
| UnsetSigChldHandler(); |
| runtime->DidForkFromZygote(); |
| } else if (pid > 0) { |
| // the parent process |
| } |
| return pid; |
| } |
| |
| static jint Zygote_nativeForkAndSpecialize(JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, |
| jint debug_flags, jobjectArray rlimits, jint mount_external, |
| jstring se_info, jstring se_name) { |
| return ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, rlimits, 0, 0, mount_external, se_info, se_name, false); |
| } |
| |
| static jint Zygote_nativeForkSystemServer(JNIEnv* env, jclass, uid_t uid, gid_t gid, jintArray gids, |
| jint debug_flags, jobjectArray rlimits, |
| jlong permittedCapabilities, jlong effectiveCapabilities) { |
| pid_t pid = ForkAndSpecializeCommon(env, uid, gid, gids, |
| debug_flags, rlimits, |
| permittedCapabilities, effectiveCapabilities, |
| MOUNT_EXTERNAL_NONE, NULL, NULL, true); |
| if (pid > 0) { |
| // The zygote process checks whether the child process has died or not. |
| LOG(INFO) << "System server process " << pid << " has been created"; |
| gSystemServerPid = pid; |
| // There is a slight window that the system server process has crashed |
| // but it went unnoticed because we haven't published its pid yet. So |
| // we recheck here just to make sure that all is well. |
| int status; |
| if (waitpid(pid, &status, WNOHANG) == pid) { |
| LOG(FATAL) << "System server process " << pid << " has died. Restarting Zygote!"; |
| } |
| } |
| return pid; |
| } |
| |
| static JNINativeMethod gMethods[] = { |
| NATIVE_METHOD(Zygote, nativeForkAndSpecialize, "(II[II[[IILjava/lang/String;Ljava/lang/String;)I"), |
| NATIVE_METHOD(Zygote, nativeForkSystemServer, "(II[II[[IJJ)I"), |
| }; |
| |
| void register_dalvik_system_Zygote(JNIEnv* env) { |
| REGISTER_NATIVE_METHODS("dalvik/system/Zygote"); |
| } |
| |
| } // namespace art |