com.android.internal.os.ZygoteConnection Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of android-all Show documentation
Show all versions of android-all Show documentation
A library jar that provides APIs for Applications written for the Google Android Platform.
/*
* Copyright (C) 2007 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.net.Credentials;
import android.net.LocalSocket;
import android.os.Process;
import android.os.SELinux;
import android.os.SystemProperties;
import android.system.ErrnoException;
import android.system.Os;
import android.util.Log;
import dalvik.system.PathClassLoader;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import libcore.io.IoUtils;
import android.os.SystemClock;
import android.util.Slog;
/**
* A connection that can make spawn requests.
*/
class ZygoteConnection {
private static final String TAG = "Zygote";
/** a prototype instance for a future List.toArray() */
private static final int[][] intArray2d = new int[0][0];
/**
* {@link android.net.LocalSocket#setSoTimeout} value for connections.
* Effectively, the amount of time a requestor has between the start of
* the request and the completed request. The select-loop mode Zygote
* doesn't have the logic to return to the select loop in the middle of
* a request, so we need to time out here to avoid being denial-of-serviced.
*/
private static final int CONNECTION_TIMEOUT_MILLIS = 1000;
/** max number of arguments that a connection can specify */
private static final int MAX_ZYGOTE_ARGC = 1024;
/**
* The command socket.
*
* mSocket is retained in the child process in "peer wait" mode, so
* that it closes when the child process terminates. In other cases,
* it is closed in the peer.
*/
private final LocalSocket mSocket;
private final DataOutputStream mSocketOutStream;
private final BufferedReader mSocketReader;
private final Credentials peer;
private final String peerSecurityContext;
private final String abiList;
/**
* Constructs instance from connected socket.
*
* @param socket non-null; connected socket
* @param abiList non-null; a list of ABIs this zygote supports.
* @throws IOException
*/
ZygoteConnection(LocalSocket socket, String abiList) throws IOException {
mSocket = socket;
this.abiList = abiList;
mSocketOutStream
= new DataOutputStream(socket.getOutputStream());
mSocketReader = new BufferedReader(
new InputStreamReader(socket.getInputStream()), 256);
mSocket.setSoTimeout(CONNECTION_TIMEOUT_MILLIS);
try {
peer = mSocket.getPeerCredentials();
} catch (IOException ex) {
Log.e(TAG, "Cannot read peer credentials", ex);
throw ex;
}
peerSecurityContext = SELinux.getPeerContext(mSocket.getFileDescriptor());
}
/**
* Temporary hack: check time since start time and log if over a fixed threshold.
*
*/
private void checkTime(long startTime, String where) {
long now = SystemClock.elapsedRealtime();
if ((now-startTime) > 1000) {
// If we are taking more than a second, log about it.
Slog.w(TAG, "Slow operation: " + (now-startTime) + "ms so far, now at " + where);
}
}
/**
* Returns the file descriptor of the associated socket.
*
* @return null-ok; file descriptor
*/
FileDescriptor getFileDescriptor() {
return mSocket.getFileDescriptor();
}
/**
* Reads one start command from the command socket. If successful,
* a child is forked and a {@link ZygoteInit.MethodAndArgsCaller}
* exception is thrown in that child while in the parent process,
* the method returns normally. On failure, the child is not
* spawned and messages are printed to the log and stderr. Returns
* a boolean status value indicating whether an end-of-file on the command
* socket has been encountered.
*
* @return false if command socket should continue to be read from, or
* true if an end-of-file has been encountered.
* @throws ZygoteInit.MethodAndArgsCaller trampoline to invoke main()
* method in child process
*/
boolean runOnce() throws ZygoteInit.MethodAndArgsCaller {
String args[];
Arguments parsedArgs = null;
FileDescriptor[] descriptors;
long startTime = SystemClock.elapsedRealtime();
try {
args = readArgumentList();
descriptors = mSocket.getAncillaryFileDescriptors();
} catch (IOException ex) {
Log.w(TAG, "IOException on command socket " + ex.getMessage());
closeSocket();
return true;
}
checkTime(startTime, "zygoteConnection.runOnce: readArgumentList");
if (args == null) {
// EOF reached.
closeSocket();
return true;
}
/** the stderr of the most recent request, if avail */
PrintStream newStderr = null;
if (descriptors != null && descriptors.length >= 3) {
newStderr = new PrintStream(
new FileOutputStream(descriptors[2]));
}
int pid = -1;
FileDescriptor childPipeFd = null;
FileDescriptor serverPipeFd = null;
try {
parsedArgs = new Arguments(args);
if (parsedArgs.abiListQuery) {
return handleAbiListQuery();
}
if (parsedArgs.permittedCapabilities != 0 || parsedArgs.effectiveCapabilities != 0) {
throw new ZygoteSecurityException("Client may not specify capabilities: " +
"permitted=0x" + Long.toHexString(parsedArgs.permittedCapabilities) +
", effective=0x" + Long.toHexString(parsedArgs.effectiveCapabilities));
}
applyUidSecurityPolicy(parsedArgs, peer, peerSecurityContext);
applyRlimitSecurityPolicy(parsedArgs, peer, peerSecurityContext);
applyInvokeWithSecurityPolicy(parsedArgs, peer, peerSecurityContext);
applyseInfoSecurityPolicy(parsedArgs, peer, peerSecurityContext);
checkTime(startTime, "zygoteConnection.runOnce: apply security policies");
applyDebuggerSystemProperty(parsedArgs);
applyInvokeWithSystemProperty(parsedArgs);
checkTime(startTime, "zygoteConnection.runOnce: apply security policies");
int[][] rlimits = null;
if (parsedArgs.rlimits != null) {
rlimits = parsedArgs.rlimits.toArray(intArray2d);
}
if (parsedArgs.runtimeInit && parsedArgs.invokeWith != null) {
FileDescriptor[] pipeFds = Os.pipe();
childPipeFd = pipeFds[1];
serverPipeFd = pipeFds[0];
ZygoteInit.setCloseOnExec(serverPipeFd, true);
}
/**
* In order to avoid leaking descriptors to the Zygote child,
* the native code must close the two Zygote socket descriptors
* in the child process before it switches from Zygote-root to
* the UID and privileges of the application being launched.
*
* In order to avoid "bad file descriptor" errors when the
* two LocalSocket objects are closed, the Posix file
* descriptors are released via a dup2() call which closes
* the socket and substitutes an open descriptor to /dev/null.
*/
int [] fdsToClose = { -1, -1 };
FileDescriptor fd = mSocket.getFileDescriptor();
if (fd != null) {
fdsToClose[0] = fd.getInt$();
}
fd = ZygoteInit.getServerSocketFileDescriptor();
if (fd != null) {
fdsToClose[1] = fd.getInt$();
}
fd = null;
checkTime(startTime, "zygoteConnection.runOnce: preForkAndSpecialize");
pid = Zygote.forkAndSpecialize(parsedArgs.uid, parsedArgs.gid, parsedArgs.gids,
parsedArgs.debugFlags, rlimits, parsedArgs.mountExternal, parsedArgs.seInfo,
parsedArgs.niceName, fdsToClose, parsedArgs.instructionSet,
parsedArgs.appDataDir);
checkTime(startTime, "zygoteConnection.runOnce: postForkAndSpecialize");
} catch (IOException ex) {
logAndPrintError(newStderr, "Exception creating pipe", ex);
} catch (ErrnoException ex) {
logAndPrintError(newStderr, "Exception creating pipe", ex);
} catch (IllegalArgumentException ex) {
logAndPrintError(newStderr, "Invalid zygote arguments", ex);
} catch (ZygoteSecurityException ex) {
logAndPrintError(newStderr,
"Zygote security policy prevents request: ", ex);
}
try {
if (pid == 0) {
// in child
IoUtils.closeQuietly(serverPipeFd);
serverPipeFd = null;
handleChildProc(parsedArgs, descriptors, childPipeFd, newStderr);
// should never get here, the child is expected to either
// throw ZygoteInit.MethodAndArgsCaller or exec().
return true;
} else {
// in parent...pid of < 0 means failure
IoUtils.closeQuietly(childPipeFd);
childPipeFd = null;
return handleParentProc(pid, descriptors, serverPipeFd, parsedArgs);
}
} finally {
IoUtils.closeQuietly(childPipeFd);
IoUtils.closeQuietly(serverPipeFd);
}
}
private boolean handleAbiListQuery() {
try {
final byte[] abiListBytes = abiList.getBytes(StandardCharsets.US_ASCII);
mSocketOutStream.writeInt(abiListBytes.length);
mSocketOutStream.write(abiListBytes);
return false;
} catch (IOException ioe) {
Log.e(TAG, "Error writing to command socket", ioe);
return true;
}
}
/**
* Closes socket associated with this connection.
*/
void closeSocket() {
try {
mSocket.close();
} catch (IOException ex) {
Log.e(TAG, "Exception while closing command "
+ "socket in parent", ex);
}
}
/**
* Handles argument parsing for args related to the zygote spawner.
*
* Current recognized args:
*
* - --setuid=uid of child process, defaults to 0
*
- --setgid=gid of child process, defaults to 0
*
- --setgroups=comma-separated list of supplimentary gid's
*
- --capabilities=a pair of comma-separated integer strings
* indicating Linux capabilities(2) set for child. The first string
* represents the
permitted set, and the second the
* effective set. Precede each with 0 or
* 0x for octal or hexidecimal value. If unspecified, both default to 0.
* This parameter is only applied if the uid of the new process will
* be non-0.
* - --rlimit=r,c,mtuple of values for setrlimit() call.
*
r is the resource, c and m
* are the settings for current and max value.
* - --classpath=colon-separated classpath indicates
* that the specified class (which must b first non-flag argument) should
* be loaded from jar files in the specified classpath. Incompatible with
* --runtime-init
*
- --runtime-init indicates that the remaining arg list should
* be handed off to com.android.internal.os.RuntimeInit, rather than
* processed directly
* Android runtime startup (eg, Binder initialization) is also eschewed.
*
- --nice-name=nice name to appear in ps
*
- If
--runtime-init is present:
* [--] <args for RuntimeInit >
* - If
--runtime-init is absent:
* [--] <classname> [args...]
* - --instruction-set=instruction-set-string which instruction set to use/emulate.
*
*/
static class Arguments {
/** from --setuid */
int uid = 0;
boolean uidSpecified;
/** from --setgid */
int gid = 0;
boolean gidSpecified;
/** from --setgroups */
int[] gids;
/**
* From --enable-debugger, --enable-checkjni, --enable-assert,
* --enable-safemode, and --enable-jni-logging.
*/
int debugFlags;
/** From --mount-external */
int mountExternal = Zygote.MOUNT_EXTERNAL_NONE;
/** from --target-sdk-version. */
int targetSdkVersion;
boolean targetSdkVersionSpecified;
/** from --classpath */
String classpath;
/** from --runtime-init */
boolean runtimeInit;
/** from --nice-name */
String niceName;
/** from --capabilities */
boolean capabilitiesSpecified;
long permittedCapabilities;
long effectiveCapabilities;
/** from --seinfo */
boolean seInfoSpecified;
String seInfo;
/** from all --rlimit=r,c,m */
ArrayList rlimits;
/** from --invoke-with */
String invokeWith;
/**
* Any args after and including the first non-option arg
* (or after a '--')
*/
String remainingArgs[];
/**
* Whether the current arguments constitute an ABI list query.
*/
boolean abiListQuery;
/**
* The instruction set to use, or null when not important.
*/
String instructionSet;
/**
* The app data directory. May be null, e.g., for the system server. Note that this might
* not be reliable in the case of process-sharing apps.
*/
String appDataDir;
/**
* Constructs instance and parses args
* @param args zygote command-line args
* @throws IllegalArgumentException
*/
Arguments(String args[]) throws IllegalArgumentException {
parseArgs(args);
}
/**
* Parses the commandline arguments intended for the Zygote spawner
* (such as "--setuid=" and "--setgid=") and creates an array
* containing the remaining args.
*
* Per security review bug #1112214, duplicate args are disallowed in
* critical cases to make injection harder.
*/
private void parseArgs(String args[])
throws IllegalArgumentException {
int curArg = 0;
for ( /* curArg */ ; curArg < args.length; curArg++) {
String arg = args[curArg];
if (arg.equals("--")) {
curArg++;
break;
} else if (arg.startsWith("--setuid=")) {
if (uidSpecified) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
uidSpecified = true;
uid = Integer.parseInt(
arg.substring(arg.indexOf('=') + 1));
} else if (arg.startsWith("--setgid=")) {
if (gidSpecified) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
gidSpecified = true;
gid = Integer.parseInt(
arg.substring(arg.indexOf('=') + 1));
} else if (arg.startsWith("--target-sdk-version=")) {
if (targetSdkVersionSpecified) {
throw new IllegalArgumentException(
"Duplicate target-sdk-version specified");
}
targetSdkVersionSpecified = true;
targetSdkVersion = Integer.parseInt(
arg.substring(arg.indexOf('=') + 1));
} else if (arg.equals("--enable-debugger")) {
debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER;
} else if (arg.equals("--enable-safemode")) {
debugFlags |= Zygote.DEBUG_ENABLE_SAFEMODE;
} else if (arg.equals("--enable-checkjni")) {
debugFlags |= Zygote.DEBUG_ENABLE_CHECKJNI;
} else if (arg.equals("--enable-jni-logging")) {
debugFlags |= Zygote.DEBUG_ENABLE_JNI_LOGGING;
} else if (arg.equals("--enable-assert")) {
debugFlags |= Zygote.DEBUG_ENABLE_ASSERT;
} else if (arg.equals("--runtime-init")) {
runtimeInit = true;
} else if (arg.startsWith("--seinfo=")) {
if (seInfoSpecified) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
seInfoSpecified = true;
seInfo = arg.substring(arg.indexOf('=') + 1);
} else if (arg.startsWith("--capabilities=")) {
if (capabilitiesSpecified) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
capabilitiesSpecified = true;
String capString = arg.substring(arg.indexOf('=')+1);
String[] capStrings = capString.split(",", 2);
if (capStrings.length == 1) {
effectiveCapabilities = Long.decode(capStrings[0]);
permittedCapabilities = effectiveCapabilities;
} else {
permittedCapabilities = Long.decode(capStrings[0]);
effectiveCapabilities = Long.decode(capStrings[1]);
}
} else if (arg.startsWith("--rlimit=")) {
// Duplicate --rlimit arguments are specifically allowed.
String[] limitStrings
= arg.substring(arg.indexOf('=')+1).split(",");
if (limitStrings.length != 3) {
throw new IllegalArgumentException(
"--rlimit= should have 3 comma-delimited ints");
}
int[] rlimitTuple = new int[limitStrings.length];
for(int i=0; i < limitStrings.length; i++) {
rlimitTuple[i] = Integer.parseInt(limitStrings[i]);
}
if (rlimits == null) {
rlimits = new ArrayList();
}
rlimits.add(rlimitTuple);
} else if (arg.equals("-classpath")) {
if (classpath != null) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
try {
classpath = args[++curArg];
} catch (IndexOutOfBoundsException ex) {
throw new IllegalArgumentException(
"-classpath requires argument");
}
} else if (arg.startsWith("--setgroups=")) {
if (gids != null) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
String[] params
= arg.substring(arg.indexOf('=') + 1).split(",");
gids = new int[params.length];
for (int i = params.length - 1; i >= 0 ; i--) {
gids[i] = Integer.parseInt(params[i]);
}
} else if (arg.equals("--invoke-with")) {
if (invokeWith != null) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
try {
invokeWith = args[++curArg];
} catch (IndexOutOfBoundsException ex) {
throw new IllegalArgumentException(
"--invoke-with requires argument");
}
} else if (arg.startsWith("--nice-name=")) {
if (niceName != null) {
throw new IllegalArgumentException(
"Duplicate arg specified");
}
niceName = arg.substring(arg.indexOf('=') + 1);
} else if (arg.equals("--mount-external-multiuser")) {
mountExternal = Zygote.MOUNT_EXTERNAL_MULTIUSER;
} else if (arg.equals("--mount-external-multiuser-all")) {
mountExternal = Zygote.MOUNT_EXTERNAL_MULTIUSER_ALL;
} else if (arg.equals("--query-abi-list")) {
abiListQuery = true;
} else if (arg.startsWith("--instruction-set=")) {
instructionSet = arg.substring(arg.indexOf('=') + 1);
} else if (arg.startsWith("--app-data-dir=")) {
appDataDir = arg.substring(arg.indexOf('=') + 1);
} else {
break;
}
}
if (runtimeInit && classpath != null) {
throw new IllegalArgumentException(
"--runtime-init and -classpath are incompatible");
}
remainingArgs = new String[args.length - curArg];
System.arraycopy(args, curArg, remainingArgs, 0,
remainingArgs.length);
}
}
/**
* Reads an argument list from the command socket/
* @return Argument list or null if EOF is reached
* @throws IOException passed straight through
*/
private String[] readArgumentList()
throws IOException {
/**
* See android.os.Process.zygoteSendArgsAndGetPid()
* Presently the wire format to the zygote process is:
* a) a count of arguments (argc, in essence)
* b) a number of newline-separated argument strings equal to count
*
* After the zygote process reads these it will write the pid of
* the child or -1 on failure.
*/
int argc;
try {
String s = mSocketReader.readLine();
if (s == null) {
// EOF reached.
return null;
}
argc = Integer.parseInt(s);
} catch (NumberFormatException ex) {
Log.e(TAG, "invalid Zygote wire format: non-int at argc");
throw new IOException("invalid wire format");
}
// See bug 1092107: large argc can be used for a DOS attack
if (argc > MAX_ZYGOTE_ARGC) {
throw new IOException("max arg count exceeded");
}
String[] result = new String[argc];
for (int i = 0; i < argc; i++) {
result[i] = mSocketReader.readLine();
if (result[i] == null) {
// We got an unexpected EOF.
throw new IOException("truncated request");
}
}
return result;
}
/**
* Applies zygote security policy per bugs #875058 and #1082165.
* Based on the credentials of the process issuing a zygote command:
*
* - uid 0 (root) may specify any uid, gid, and setgroups() list
*
- uid 1000 (Process.SYSTEM_UID) may specify any uid > 1000 in normal
* operation. It may also specify any gid and setgroups() list it chooses.
* In factory test mode, it may specify any UID.
*
- Any other uid may not specify any uid, gid, or setgroups list. The
* uid and gid will be inherited from the requesting process.
*
*
* @param args non-null; zygote spawner arguments
* @param peer non-null; peer credentials
* @throws ZygoteSecurityException
*/
private static void applyUidSecurityPolicy(Arguments args, Credentials peer,
String peerSecurityContext)
throws ZygoteSecurityException {
int peerUid = peer.getUid();
if (peerUid == 0) {
// Root can do what it wants
} else if (peerUid == Process.SYSTEM_UID ) {
// System UID is restricted, except in factory test mode
String factoryTest = SystemProperties.get("ro.factorytest");
boolean uidRestricted;
/* In normal operation, SYSTEM_UID can only specify a restricted
* set of UIDs. In factory test mode, SYSTEM_UID may specify any uid.
*/
uidRestricted
= !(factoryTest.equals("1") || factoryTest.equals("2"));
if (uidRestricted
&& args.uidSpecified && (args.uid < Process.SYSTEM_UID)) {
throw new ZygoteSecurityException(
"System UID may not launch process with UID < "
+ Process.SYSTEM_UID);
}
} else {
// Everything else
if (args.uidSpecified || args.gidSpecified
|| args.gids != null) {
throw new ZygoteSecurityException(
"App UIDs may not specify uid's or gid's");
}
}
if (args.uidSpecified || args.gidSpecified || args.gids != null) {
boolean allowed = SELinux.checkSELinuxAccess(peerSecurityContext,
peerSecurityContext,
"zygote",
"specifyids");
if (!allowed) {
throw new ZygoteSecurityException(
"Peer may not specify uid's or gid's");
}
}
// If not otherwise specified, uid and gid are inherited from peer
if (!args.uidSpecified) {
args.uid = peer.getUid();
args.uidSpecified = true;
}
if (!args.gidSpecified) {
args.gid = peer.getGid();
args.gidSpecified = true;
}
}
/**
* Applies debugger system properties to the zygote arguments.
*
* If "ro.debuggable" is "1", all apps are debuggable. Otherwise,
* the debugger state is specified via the "--enable-debugger" flag
* in the spawn request.
*
* @param args non-null; zygote spawner args
*/
public static void applyDebuggerSystemProperty(Arguments args) {
if ("1".equals(SystemProperties.get("ro.debuggable"))) {
args.debugFlags |= Zygote.DEBUG_ENABLE_DEBUGGER;
}
}
/**
* Applies zygote security policy per bug #1042973. Based on the credentials
* of the process issuing a zygote command:
*
* - peers of uid 0 (root) and uid 1000 (Process.SYSTEM_UID)
* may specify any rlimits.
*
- All other uids may not specify rlimits.
*
* @param args non-null; zygote spawner arguments
* @param peer non-null; peer credentials
* @throws ZygoteSecurityException
*/
private static void applyRlimitSecurityPolicy(
Arguments args, Credentials peer, String peerSecurityContext)
throws ZygoteSecurityException {
int peerUid = peer.getUid();
if (!(peerUid == 0 || peerUid == Process.SYSTEM_UID)) {
// All peers with UID other than root or SYSTEM_UID
if (args.rlimits != null) {
throw new ZygoteSecurityException(
"This UID may not specify rlimits.");
}
}
if (args.rlimits != null) {
boolean allowed = SELinux.checkSELinuxAccess(peerSecurityContext,
peerSecurityContext,
"zygote",
"specifyrlimits");
if (!allowed) {
throw new ZygoteSecurityException(
"Peer may not specify rlimits");
}
}
}
/**
* Applies zygote security policy.
* Based on the credentials of the process issuing a zygote command:
*
* - uid 0 (root) may specify --invoke-with to launch Zygote with a
* wrapper command.
*
- Any other uid may not specify any invoke-with argument.
*
*
* @param args non-null; zygote spawner arguments
* @param peer non-null; peer credentials
* @throws ZygoteSecurityException
*/
private static void applyInvokeWithSecurityPolicy(Arguments args, Credentials peer,
String peerSecurityContext)
throws ZygoteSecurityException {
int peerUid = peer.getUid();
if (args.invokeWith != null && peerUid != 0) {
throw new ZygoteSecurityException("Peer is not permitted to specify "
+ "an explicit invoke-with wrapper command");
}
if (args.invokeWith != null) {
boolean allowed = SELinux.checkSELinuxAccess(peerSecurityContext,
peerSecurityContext,
"zygote",
"specifyinvokewith");
if (!allowed) {
throw new ZygoteSecurityException("Peer is not permitted to specify "
+ "an explicit invoke-with wrapper command");
}
}
}
/**
* Applies zygote security policy for SELinux information.
*
* @param args non-null; zygote spawner arguments
* @param peer non-null; peer credentials
* @throws ZygoteSecurityException
*/
private static void applyseInfoSecurityPolicy(
Arguments args, Credentials peer, String peerSecurityContext)
throws ZygoteSecurityException {
int peerUid = peer.getUid();
if (args.seInfo == null) {
// nothing to check
return;
}
if (!(peerUid == 0 || peerUid == Process.SYSTEM_UID)) {
// All peers with UID other than root or SYSTEM_UID
throw new ZygoteSecurityException(
"This UID may not specify SELinux info.");
}
boolean allowed = SELinux.checkSELinuxAccess(peerSecurityContext,
peerSecurityContext,
"zygote",
"specifyseinfo");
if (!allowed) {
throw new ZygoteSecurityException(
"Peer may not specify SELinux info");
}
return;
}
/**
* Applies invoke-with system properties to the zygote arguments.
*
* @param args non-null; zygote args
*/
public static void applyInvokeWithSystemProperty(Arguments args) {
if (args.invokeWith == null && args.niceName != null) {
if (args.niceName != null) {
String property = "wrap." + args.niceName;
if (property.length() > 31) {
property = property.substring(0, 31);
}
args.invokeWith = SystemProperties.get(property);
if (args.invokeWith != null && args.invokeWith.length() == 0) {
args.invokeWith = null;
}
}
}
}
/**
* Handles post-fork setup of child proc, closing sockets as appropriate,
* reopen stdio as appropriate, and ultimately throwing MethodAndArgsCaller
* if successful or returning if failed.
*
* @param parsedArgs non-null; zygote args
* @param descriptors null-ok; new file descriptors for stdio if available.
* @param pipeFd null-ok; pipe for communication back to Zygote.
* @param newStderr null-ok; stream to use for stderr until stdio
* is reopened.
*
* @throws ZygoteInit.MethodAndArgsCaller on success to
* trampoline to code that invokes static main.
*/
private void handleChildProc(Arguments parsedArgs,
FileDescriptor[] descriptors, FileDescriptor pipeFd, PrintStream newStderr)
throws ZygoteInit.MethodAndArgsCaller {
/**
* By the time we get here, the native code has closed the two actual Zygote
* socket connections, and substituted /dev/null in their place. The LocalSocket
* objects still need to be closed properly.
*/
closeSocket();
ZygoteInit.closeServerSocket();
if (descriptors != null) {
try {
ZygoteInit.reopenStdio(descriptors[0],
descriptors[1], descriptors[2]);
for (FileDescriptor fd: descriptors) {
IoUtils.closeQuietly(fd);
}
newStderr = System.err;
} catch (IOException ex) {
Log.e(TAG, "Error reopening stdio", ex);
}
}
if (parsedArgs.niceName != null) {
Process.setArgV0(parsedArgs.niceName);
}
if (parsedArgs.runtimeInit) {
if (parsedArgs.invokeWith != null) {
WrapperInit.execApplication(parsedArgs.invokeWith,
parsedArgs.niceName, parsedArgs.targetSdkVersion,
pipeFd, parsedArgs.remainingArgs);
} else {
RuntimeInit.zygoteInit(parsedArgs.targetSdkVersion,
parsedArgs.remainingArgs, null /* classLoader */);
}
} else {
String className;
try {
className = parsedArgs.remainingArgs[0];
} catch (ArrayIndexOutOfBoundsException ex) {
logAndPrintError(newStderr,
"Missing required class name argument", null);
return;
}
String[] mainArgs = new String[parsedArgs.remainingArgs.length - 1];
System.arraycopy(parsedArgs.remainingArgs, 1,
mainArgs, 0, mainArgs.length);
if (parsedArgs.invokeWith != null) {
WrapperInit.execStandalone(parsedArgs.invokeWith,
parsedArgs.classpath, className, mainArgs);
} else {
ClassLoader cloader;
if (parsedArgs.classpath != null) {
cloader = new PathClassLoader(parsedArgs.classpath,
ClassLoader.getSystemClassLoader());
} else {
cloader = ClassLoader.getSystemClassLoader();
}
try {
ZygoteInit.invokeStaticMain(cloader, className, mainArgs);
} catch (RuntimeException ex) {
logAndPrintError(newStderr, "Error starting.", ex);
}
}
}
}
/**
* Handles post-fork cleanup of parent proc
*
* @param pid != 0; pid of child if > 0 or indication of failed fork
* if < 0;
* @param descriptors null-ok; file descriptors for child's new stdio if
* specified.
* @param pipeFd null-ok; pipe for communication with child.
* @param parsedArgs non-null; zygote args
* @return true for "exit command loop" and false for "continue command
* loop"
*/
private boolean handleParentProc(int pid,
FileDescriptor[] descriptors, FileDescriptor pipeFd, Arguments parsedArgs) {
if (pid > 0) {
setChildPgid(pid);
}
if (descriptors != null) {
for (FileDescriptor fd: descriptors) {
IoUtils.closeQuietly(fd);
}
}
boolean usingWrapper = false;
if (pipeFd != null && pid > 0) {
DataInputStream is = new DataInputStream(new FileInputStream(pipeFd));
int innerPid = -1;
try {
innerPid = is.readInt();
} catch (IOException ex) {
Log.w(TAG, "Error reading pid from wrapped process, child may have died", ex);
} finally {
try {
is.close();
} catch (IOException ex) {
}
}
// Ensure that the pid reported by the wrapped process is either the
// child process that we forked, or a descendant of it.
if (innerPid > 0) {
int parentPid = innerPid;
while (parentPid > 0 && parentPid != pid) {
parentPid = Process.getParentPid(parentPid);
}
if (parentPid > 0) {
Log.i(TAG, "Wrapped process has pid " + innerPid);
pid = innerPid;
usingWrapper = true;
} else {
Log.w(TAG, "Wrapped process reported a pid that is not a child of "
+ "the process that we forked: childPid=" + pid
+ " innerPid=" + innerPid);
}
}
}
try {
mSocketOutStream.writeInt(pid);
mSocketOutStream.writeBoolean(usingWrapper);
} catch (IOException ex) {
Log.e(TAG, "Error writing to command socket", ex);
return true;
}
return false;
}
private void setChildPgid(int pid) {
// Try to move the new child into the peer's process group.
try {
ZygoteInit.setpgid(pid, ZygoteInit.getpgid(peer.getPid()));
} catch (IOException ex) {
// This exception is expected in the case where
// the peer is not in our session
// TODO get rid of this log message in the case where
// getsid(0) != getsid(peer.getPid())
Log.i(TAG, "Zygote: setpgid failed. This is "
+ "normal if peer is not in our session");
}
}
/**
* Logs an error message and prints it to the specified stream, if
* provided
*
* @param newStderr null-ok; a standard error stream
* @param message non-null; error message
* @param ex null-ok an exception
*/
private static void logAndPrintError (PrintStream newStderr,
String message, Throwable ex) {
Log.e(TAG, message, ex);
if (newStderr != null) {
newStderr.println(message + (ex == null ? "" : ex));
}
}
}