Hesham/wireguard-android
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RootShell: Use a lock object instead of sync methods

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This avoids exposing the synchronization implementation details
in the class's interface.

Signed-off-by: Samuel Holland <samuel@sholland.org>
This commit is contained in:
Samuel Holland 2018-01-16 05:47:10 -06:00
parent 75aeec035c
commit d56eda2fd6
1 changed files with 98 additions and 88 deletions
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24
app/src/main/java/com/wireguard/android/util/RootShell.java
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@ -31,6 +31,7 @@ public class RootShell {
private final String deviceNotRootedMessage; private final String deviceNotRootedMessage;
private final File localBinaryDir; private final File localBinaryDir;
private final File localTemporaryDir; private final File localTemporaryDir;
private final Object lock = new Object();
private final String preamble; private final String preamble;
private Process process; private Process process;
private BufferedReader stderr; private BufferedReader stderr;
@ -57,16 +58,18 @@ public class RootShell {
return false; return false;
} }
public synchronized boolean isRunning() { private boolean isRunning() {
synchronized (lock) {
try { try {
// Throws an exception if the process hasn't finished yet. // Throws an exception if the process hasn't finished yet.
if (process != null) if (process != null)
process.exitValue(); process.exitValue();
return false;
} catch (final IllegalThreadStateException ignored) { } catch (final IllegalThreadStateException ignored) {
// The existing process is still running. // The existing process is still running.
return true; return true;
} }
return false; }
} }
/** /**
@ -77,8 +80,10 @@ public class RootShell {
* @param command Command to run as root. * @param command Command to run as root.
* @return The exit value of the command. * @return The exit value of the command.
*/ */
public synchronized int run(final Collection<String> output, final String command) public int run(final Collection<String> output, final String command)
throws IOException, NoRootException { throws IOException, NoRootException {
synchronized (lock) {
/* Start inside synchronized block to prevent a concurrent call to stop(). */
start(); start();
final String marker = UUID.randomUUID().toString(); final String marker = UUID.randomUUID().toString();
final String script = "echo " + marker + "; echo " + marker + " >&2; (" + command + final String script = "echo " + marker + "; echo " + marker + " >&2; (" + command +
@ -121,16 +126,18 @@ public class RootShell {
Log.v(TAG, "exit: " + errnoStdout); Log.v(TAG, "exit: " + errnoStdout);
return errnoStdout; return errnoStdout;
} }
}
public synchronized void start() throws IOException, NoRootException { public void start() throws IOException, NoRootException {
if (!isExecutableInPath(SU))
throw new NoRootException(deviceNotRootedMessage);
synchronized (lock) {
if (isRunning()) if (isRunning())
return; return;
if (!localBinaryDir.isDirectory() && !localBinaryDir.mkdirs()) if (!localBinaryDir.isDirectory() && !localBinaryDir.mkdirs())
throw new FileNotFoundException("Could not create local binary directory"); throw new FileNotFoundException("Could not create local binary directory");
if (!localTemporaryDir.isDirectory() && !localTemporaryDir.mkdirs()) if (!localTemporaryDir.isDirectory() && !localTemporaryDir.mkdirs())
throw new FileNotFoundException("Could not create local temporary directory"); throw new FileNotFoundException("Could not create local temporary directory");
if (!isExecutableInPath(SU))
throw new NoRootException(deviceNotRootedMessage);
try { try {
final ProcessBuilder builder = new ProcessBuilder().command(SU); final ProcessBuilder builder = new ProcessBuilder().command(SU);
builder.environment().put("LC_ALL", "C"); builder.environment().put("LC_ALL", "C");
@ -167,13 +174,16 @@ public class RootShell {
throw e; throw e;
} }
} }
}
public synchronized void stop() throws IOException { public void stop() {
synchronized (lock) {
if (process != null) { if (process != null) {
process.destroy(); process.destroy();
process = null; process = null;
} }
} }
}
public static class NoRootException extends Exception { public static class NoRootException extends Exception {
public NoRootException(final String message, final Throwable cause) { public NoRootException(final String message, final Throwable cause) {