package com.bigdata.counters.linux;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.log4j.Logger;
import org.apache.system.SystemUtil;
/**
* Reports on the kernel version for a linux (or OSX) host.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan
* Thompson</a>
* @version $Id$
*
* @todo there is more information lurking in the kernel version (under linux).
*
* @see http://en.wikipedia.org/wiki/Linux_kernel for a summary of linux
* kernel versioning.
*/
public class KernelVersion {
static private final Logger log = Logger.getLogger(KernelVersion.class);
public final int version;
public final int major;
public final int minor;
private static Pattern p = Pattern.compile("^([0-9]+).([0-9]+).([0-9]+).*");
public KernelVersion(final String val) {
if (val == null)
throw new IllegalArgumentException();
final Matcher m = p.matcher(val);
if(!m.matches())
throw new IllegalArgumentException("Not a kernel version? [" + val
+ "]");
version = Integer.parseInt(m.group(1));
major = Integer.parseInt(m.group(2));
minor = Integer.parseInt(m.group(3));
}
public String toString() {
return "{version=" + version + ", major=" + major + ", minor=" + minor
+ "}";
}
/**
* Return the version of the Linux kernel as reported by
* <code>uname</code>
*
* @return The {@link KernelVersion}
*
* @throws RuntimeException
* if anything goes wrong.
*/
static public KernelVersion get() {
final List<String> commands = new LinkedList<String>();
final Process pr;
try {
if (SystemUtil.isLinux()) {
commands.add("/bin/uname");
} else if (SystemUtil.isOSX()) {
commands.add("/usr/bin/uname");
} else {
/*
* Attempt uname -r at with this path, but this is an unknown
* OS.
*/
commands.add("/bin/uname");
}
commands.add("-r");
final ProcessBuilder pb = new ProcessBuilder(commands);
pr = pb.start();
pr.waitFor();
} catch (Exception ex) {
throw new RuntimeException("Problem running command: ["
+ commands + "]", ex);
}
if (pr.exitValue() == 0) {
final BufferedReader outReader = new BufferedReader(
new InputStreamReader(pr.getInputStream()));
final String val;
try {
val = outReader.readLine();
} catch (IOException ex) {
throw new RuntimeException(ex);
} finally {
try {
outReader.close();
} catch (IOException ex) {
log.error(ex, ex);
}
}
if (val == null)
throw new RuntimeException("Nothing returned.");
if(log.isInfoEnabled())
log.info("read: [" + val + "]");
return new KernelVersion(val.trim());
} else {
throw new RuntimeException(
"Could not get kernal version: exitValue=" + pr.exitValue());
}
}
/**
* Prints the data reported by {@link KernelVersion#get()}.
*
* @param args
* ignored.
*/
public static void main(final String[] args) {
final KernelVersion kver = KernelVersion.get();
System.out.println("kernel version: "+kver);
}
}