Merge "Move most zygote related code to frameworks/base."

4 files changed, 120 insertions, 608 deletions

diff --git a/runtime/Android.mk b/runtime/Android.mk
index e8224cd..697d1a3 100644
--- a/runtime/Android.mk
+++ b/runtime/Android.mk
@@ -103,7 +103,7 @@ LIBART_COMMON_SRC_FILES := \
 	native/dalvik_system_VMDebug.cc \
 	native/dalvik_system_VMRuntime.cc \
 	native/dalvik_system_VMStack.cc \
-	native/dalvik_system_Zygote.cc \
+	native/dalvik_system_ZygoteHooks.cc \
 	native/java_lang_Class.cc \
 	native/java_lang_DexCache.cc \
 	native/java_lang_Object.cc \
diff --git a/runtime/native/dalvik_system_Zygote.cc b/runtime/native/dalvik_system_Zygote.cc
deleted file mode 100644
index 0307207..0000000
--- a/runtime/native/dalvik_system_Zygote.cc
+++ /dev/null
@@ -1,606 +0,0 @@
-/*
- * 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/resource.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <unistd.h>
-#include <fcntl.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>
-#if defined(HAVE_ANDROID_OS)
-#include <sys/capability.h>
-#endif
-#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++) {
-    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 (TEMP_FAILURE_RETRY(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 (TEMP_FAILURE_RETRY(
-              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 (TEMP_FAILURE_RETRY(
-            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 to close down the Zygote socket file descriptors while
-// the child is still running as root with Zygote's privileges.  Each
-// descriptor (if any) is closed via dup2(), replacing it with a valid
-// (open) descriptor to /dev/null.
-
-static void DetachDescriptors(JNIEnv* env, jintArray fdsToClose) {
-  if (!fdsToClose) {
-    return;
-  }
-  jsize count = env->GetArrayLength(fdsToClose);
-  jint *ar = env->GetIntArrayElements(fdsToClose, 0);
-  if (!ar) {
-      PLOG(FATAL) << "Bad fd array";
-  }
-  jsize i;
-  int devnull;
-  for (i = 0; i < count; i++) {
-    devnull = open("/dev/null", O_RDWR);
-    if (devnull < 0) {
-      PLOG(FATAL) << "Failed to open /dev/null";
-      continue;
-    }
-    PLOG(VERBOSE) << "Switching descriptor " << ar[i] << " to /dev/null";
-    if (dup2(devnull, ar[i]) < 0) {
-      PLOG(FATAL) << "Failed dup2() on descriptor " << ar[i];
-    }
-    close(devnull);
-  }
-}
-
-// 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, jintArray fdsToClose) {
-  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;
-
-    // Clean up any descriptors which must be closed immediately
-    DetachDescriptors(env, fdsToClose);
-
-    // 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,
-                                           jintArray fdsToClose) {
-  return ForkAndSpecializeCommon(env, uid, gid, gids, debug_flags, rlimits, 0, 0, mount_external,
-                                 se_info, se_name, false, fdsToClose);
-}
-
-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, NULL);
-  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)I"),
-  NATIVE_METHOD(Zygote, nativeForkSystemServer, "(II[II[[IJJ)I"),
-};
-
-void register_dalvik_system_Zygote(JNIEnv* env) {
-  REGISTER_NATIVE_METHODS("dalvik/system/Zygote");
-}
-
-}  // namespace art
diff --git a/runtime/native/dalvik_system_ZygoteHooks.cc b/runtime/native/dalvik_system_ZygoteHooks.cc
new file mode 100644
index 0000000..5455daa
--- /dev/null
+++ b/runtime/native/dalvik_system_ZygoteHooks.cc
@@ -0,0 +1,118 @@
+/*
+ * 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.
+ */
+
+#include <stdlib.h>
+
+#include "debugger.h"
+#include "jni_internal.h"
+#include "JNIHelp.h"
+#include "thread-inl.h"
+
+#if defined(HAVE_PRCTL)
+#include <sys/prctl.h>
+#endif
+
+namespace art {
+
+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 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);
+  }
+}
+
+static jlong ZygoteHooks_nativePreFork(JNIEnv* env, jclass) {
+  Runtime* runtime = Runtime::Current();
+  CHECK(runtime->IsZygote()) << "runtime instance not started with -Xzygote";
+  if (!runtime->PreZygoteFork()) {
+    LOG(FATAL) << "pre-fork heap failed";
+  }
+
+  // Grab thread before fork potentially makes Thread::pthread_key_self_ unusable.
+  Thread* self = Thread::Current();
+  return reinterpret_cast<jlong>(self);
+}
+
+static void ZygoteHooks_nativePostForkChild(JNIEnv* env, jclass, jlong token, jint debug_flags) {
+  Thread* thread = reinterpret_cast<Thread*>(token);
+  // Our system thread ID, etc, has changed so reset Thread state.
+  thread->InitAfterFork();
+  EnableDebugFeatures(debug_flags);
+  Runtime::Current()->DidForkFromZygote();
+}
+
+static JNINativeMethod gMethods[] = {
+  NATIVE_METHOD(ZygoteHooks, nativePreFork, "()J"),
+  NATIVE_METHOD(ZygoteHooks, nativePostForkChild, "(JI)V"),
+};
+
+void register_dalvik_system_ZygoteHooks(JNIEnv* env) {
+  REGISTER_NATIVE_METHODS("dalvik/system/ZygoteHooks");
+}
+
+}  // namespace art
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 23405e6..a830018 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -708,7 +708,7 @@ void Runtime::RegisterRuntimeNativeMethods(JNIEnv* env) {
   REGISTER(register_dalvik_system_VMDebug);
   REGISTER(register_dalvik_system_VMRuntime);
   REGISTER(register_dalvik_system_VMStack);
-  REGISTER(register_dalvik_system_Zygote);
+  REGISTER(register_dalvik_system_ZygoteHooks);
   REGISTER(register_java_lang_Class);
   REGISTER(register_java_lang_DexCache);
   REGISTER(register_java_lang_Object);