/* * 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.Trace; import dalvik.system.ZygoteHooks; import android.system.ErrnoException; import android.system.Os; /** @hide */ public final class Zygote { /* * Bit values for "debugFlags" argument. The definitions are duplicated * in the native code. */ /** enable debugging over JDWP */ public static final int DEBUG_ENABLE_DEBUGGER = 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; /** enable the JIT compiler */ public static final int DEBUG_ENABLE_JIT = 1 << 5; /** Force generation of native debugging information. */ public static final int DEBUG_GENERATE_DEBUG_INFO = 1 << 6; /** No external storage should be mounted. */ public static final int MOUNT_EXTERNAL_NONE = 0; /** Default external storage should be mounted. */ public static final int MOUNT_EXTERNAL_DEFAULT = 1; /** Read-only external storage should be mounted. */ public static final int MOUNT_EXTERNAL_READ = 2; /** Read-write external storage should be mounted. */ public static final int MOUNT_EXTERNAL_WRITE = 3; private static final ZygoteHooks VM_HOOKS = new ZygoteHooks(); private Zygote() {} /** * Forks a new VM instance. The current VM must have been started * with the -Xzygote flag. <b>NOTE: new instance keeps all * root capabilities. The new process is expected to call capset()</b>. * * @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 debugFlags bit flags that enable debugging 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 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 debugFlags, int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose, String instructionSet, String appDataDir) { VM_HOOKS.preFork(); int pid = nativeForkAndSpecialize( uid, gid, gids, debugFlags, rlimits, mountExternal, seInfo, niceName, fdsToClose, instructionSet, appDataDir); // Enable tracing as soon as possible for the child process. if (pid == 0) { Trace.setTracingEnabled(true); // 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 debugFlags, int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose, String instructionSet, String appDataDir); /** * 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 debugFlags bit flags that enable debugging 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 debugFlags, int[][] rlimits, long permittedCapabilities, long effectiveCapabilities) { VM_HOOKS.preFork(); int pid = nativeForkSystemServer( uid, gid, gids, debugFlags, rlimits, permittedCapabilities, effectiveCapabilities); // Enable tracing as soon as we enter the system_server. if (pid == 0) { Trace.setTracingEnabled(true); } VM_HOOKS.postForkCommon(); return pid; } native private static int nativeForkSystemServer(int uid, int gid, int[] gids, int debugFlags, int[][] rlimits, long permittedCapabilities, long effectiveCapabilities); private static void callPostForkChildHooks(int debugFlags, String instructionSet) { VM_HOOKS.postForkChild(debugFlags, instructionSet); } /** * 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("'"); } } }