/* * Copyright (C) 2014 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. */ package com.android.internal.os; import android.os.IVold; import android.os.Trace; import android.system.ErrnoException; import android.system.Os; import dalvik.system.ZygoteHooks; /** @hide */ public final class Zygote { /* * Bit values for "runtimeFlags" argument. The definitions are duplicated * in the native code. */ /** enable debugging over JDWP */ public static final int DEBUG_ENABLE_JDWP = 1; /** enable JNI checks */ public static final int DEBUG_ENABLE_CHECKJNI = 1 << 1; /** enable Java programming language "assert" statements */ public static final int DEBUG_ENABLE_ASSERT = 1 << 2; /** disable the AOT compiler and JIT */ public static final int DEBUG_ENABLE_SAFEMODE = 1 << 3; /** Enable logging of third-party JNI activity. */ public static final int DEBUG_ENABLE_JNI_LOGGING = 1 << 4; /** Force generation of native debugging information. */ public static final int DEBUG_GENERATE_DEBUG_INFO = 1 << 5; /** Always use JIT-ed code. */ public static final int DEBUG_ALWAYS_JIT = 1 << 6; /** Make the code native debuggable by turning off some optimizations. */ public static final int DEBUG_NATIVE_DEBUGGABLE = 1 << 7; /** Make the code Java debuggable by turning off some optimizations. */ public static final int DEBUG_JAVA_DEBUGGABLE = 1 << 8; /** Turn off the verifier. */ public static final int DISABLE_VERIFIER = 1 << 9; /** Only use oat files located in /system. Otherwise use dex/jar/apk . */ public static final int ONLY_USE_SYSTEM_OAT_FILES = 1 << 10; /** Force generation of native debugging information for backtraces. */ public static final int DEBUG_GENERATE_MINI_DEBUG_INFO = 1 << 11; /** * Hidden API access restrictions. This is a mask for bits representing the API enforcement * policy, defined by {@code @ApplicationInfo.HiddenApiEnforcementPolicy}. */ public static final int API_ENFORCEMENT_POLICY_MASK = (1 << 12) | (1 << 13); /** * Bit shift for use with {@link #API_ENFORCEMENT_POLICY_MASK}. * * (flags & API_ENFORCEMENT_POLICY_MASK) >> API_ENFORCEMENT_POLICY_SHIFT gives * @ApplicationInfo.ApiEnforcementPolicy values. */ public static final int API_ENFORCEMENT_POLICY_SHIFT = Integer.numberOfTrailingZeros(API_ENFORCEMENT_POLICY_MASK); /** * Enable system server ART profiling. */ public static final int PROFILE_SYSTEM_SERVER = 1 << 14; /** No external storage should be mounted. */ public static final int MOUNT_EXTERNAL_NONE = IVold.REMOUNT_MODE_NONE; /** Default external storage should be mounted. */ public static final int MOUNT_EXTERNAL_DEFAULT = IVold.REMOUNT_MODE_DEFAULT; /** Read-only external storage should be mounted. */ public static final int MOUNT_EXTERNAL_READ = IVold.REMOUNT_MODE_READ; /** Read-write external storage should be mounted. */ public static final int MOUNT_EXTERNAL_WRITE = IVold.REMOUNT_MODE_WRITE; private static final ZygoteHooks VM_HOOKS = new ZygoteHooks(); /** * An extraArg passed when a zygote process is forking a child-zygote, specifying a name * in the abstract socket namespace. This socket name is what the new child zygote * should listen for connections on. */ public static final String CHILD_ZYGOTE_SOCKET_NAME_ARG = "--zygote-socket="; private Zygote() {} /** Called for some security initialization before any fork. */ native static void nativeSecurityInit(); /** * Forks a new VM instance. The current VM must have been started * with the -Xzygote flag. NOTE: new instance keeps all * root capabilities. The new process is expected to call capset(). * * @param uid the UNIX uid that the new process should setuid() to after * fork()ing and and before spawning any threads. * @param gid the UNIX gid that the new process should setgid() to after * fork()ing and and before spawning any threads. * @param gids null-ok; a list of UNIX gids that the new process should * setgroups() to after fork and before spawning any threads. * @param runtimeFlags bit flags that enable ART features. * @param rlimits null-ok an array of rlimit tuples, with the second * dimension having a length of 3 and representing * (resource, rlim_cur, rlim_max). These are set via the posix * setrlimit(2) call. * @param seInfo null-ok a string specifying SELinux information for * the new process. * @param niceName null-ok a string specifying the process name. * @param fdsToClose an array of ints, holding one or more POSIX * file descriptor numbers that are to be closed by the child * (and replaced by /dev/null) after forking. An integer value * of -1 in any entry in the array means "ignore this one". * @param fdsToIgnore null-ok an array of ints, either null or holding * one or more POSIX file descriptor numbers that are to be ignored * in the file descriptor table check. * @param startChildZygote if true, the new child process will itself be a * new zygote process. * @param instructionSet null-ok the instruction set to use. * @param appDataDir null-ok the data directory of the app. * * @return 0 if this is the child, pid of the child * if this is the parent, or -1 on error. */ public static int forkAndSpecialize(int uid, int gid, int[] gids, int runtimeFlags, int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose, int[] fdsToIgnore, boolean startChildZygote, String instructionSet, String appDataDir) { VM_HOOKS.preFork(); // Resets nice priority for zygote process. resetNicePriority(); int pid = nativeForkAndSpecialize( uid, gid, gids, runtimeFlags, rlimits, mountExternal, seInfo, niceName, fdsToClose, fdsToIgnore, startChildZygote, instructionSet, appDataDir); // Enable tracing as soon as possible for the child process. if (pid == 0) { Trace.setTracingEnabled(true, runtimeFlags); // Note that this event ends at the end of handleChildProc, Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "PostFork"); } VM_HOOKS.postForkCommon(); return pid; } native private static int nativeForkAndSpecialize(int uid, int gid, int[] gids,int runtimeFlags, int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose, int[] fdsToIgnore, boolean startChildZygote, String instructionSet, String appDataDir); /** * Called to do any initialization before starting an application. */ native static void nativePreApplicationInit(); /** * Special method to start the system server process. In addition to the * common actions performed in forkAndSpecialize, the pid of the child * process is recorded such that the death of the child process will cause * zygote to exit. * * @param uid the UNIX uid that the new process should setuid() to after * fork()ing and and before spawning any threads. * @param gid the UNIX gid that the new process should setgid() to after * fork()ing and and before spawning any threads. * @param gids null-ok; a list of UNIX gids that the new process should * setgroups() to after fork and before spawning any threads. * @param runtimeFlags bit flags that enable ART features. * @param rlimits null-ok an array of rlimit tuples, with the second * dimension having a length of 3 and representing * (resource, rlim_cur, rlim_max). These are set via the posix * setrlimit(2) call. * @param permittedCapabilities argument for setcap() * @param effectiveCapabilities argument for setcap() * * @return 0 if this is the child, pid of the child * if this is the parent, or -1 on error. */ public static int forkSystemServer(int uid, int gid, int[] gids, int runtimeFlags, int[][] rlimits, long permittedCapabilities, long effectiveCapabilities) { VM_HOOKS.preFork(); // Resets nice priority for zygote process. resetNicePriority(); int pid = nativeForkSystemServer( uid, gid, gids, runtimeFlags, rlimits, permittedCapabilities, effectiveCapabilities); // Enable tracing as soon as we enter the system_server. if (pid == 0) { Trace.setTracingEnabled(true, runtimeFlags); } VM_HOOKS.postForkCommon(); return pid; } native private static int nativeForkSystemServer(int uid, int gid, int[] gids, int runtimeFlags, int[][] rlimits, long permittedCapabilities, long effectiveCapabilities); /** * Lets children of the zygote inherit open file descriptors to this path. */ native protected static void nativeAllowFileAcrossFork(String path); /** * Zygote unmount storage space on initializing. * This method is called once. */ native protected static void nativeUnmountStorageOnInit(); private static void callPostForkChildHooks(int runtimeFlags, boolean isSystemServer, boolean isZygote, String instructionSet) { VM_HOOKS.postForkChild(runtimeFlags, isSystemServer, isZygote, instructionSet); } /** * Resets the calling thread priority to the default value (Thread.NORM_PRIORITY * or nice value 0). This updates both the priority value in java.lang.Thread and * the nice value (setpriority). */ static void resetNicePriority() { Thread.currentThread().setPriority(Thread.NORM_PRIORITY); } /** * Executes "/system/bin/sh -c <command>" using the exec() system call. * This method throws a runtime exception if exec() failed, otherwise, this * method never returns. * * @param command The shell command to execute. */ public static void execShell(String command) { String[] args = { "/system/bin/sh", "-c", command }; try { Os.execv(args[0], args); } catch (ErrnoException e) { throw new RuntimeException(e); } } /** * Appends quotes shell arguments to the specified string builder. * The arguments are quoted using single-quotes, escaped if necessary, * prefixed with a space, and appended to the command. * * @param command A string builder for the shell command being constructed. * @param args An array of argument strings to be quoted and appended to the command. * @see #execShell(String) */ public static void appendQuotedShellArgs(StringBuilder command, String[] args) { for (String arg : args) { command.append(" '").append(arg.replace("'", "'\\''")).append("'"); } } }