/*
 * @(#)Syslog.java	1.1 01/01/04
 *
 * Copyright 2000-2001 john gladkih & BDI. All rights reserved.
 *
 * This software is absolutely free. You may use, distribute
 * and modify it as you wish, but you MUSTN'T remove copyright
 * information. Kinda relax.
 *
 */

package bdi.utils;

import java.net.*;
import java.io.*;
import java.util.StringTokenizer;

/**
 *
 * The Syslog class is a BSD-like Syslog implementation.
 * This implementation uses only UDP for logging.
 *
 * @author  john gladkih <john@kak-sam.to>
 * @version 1.1, 04/01/01
 *
 */

public class Syslog extends OutputStream
{
  // Facility codes

  public static final short LOG_KERN   = (0<<3);  // kernel messages
  public static final short LOG_USER   = (1<<3);  // random user-level messages
  public static final short LOG_MAIL   = (2<<3);  // mail system
  public static final short LOG_DAEMON = (3<<3);  // system daemons
  public static final short LOG_AUTH   = (4<<3);  // security/authorization messages
  public static final short LOG_SYSLOG = (5<<3);  // messages generated internally
                                                  //  by syslogd
  public static final short LOG_LPR    = (6<<3);  // line printer subsystem
  public static final short LOG_NEWS   = (7<<3);  // netnews subsystem
  public static final short LOG_UUCP   = (8<<3);  // uucp subsystem
  public static final short LOG_CRON   = (15<<3); // cron/at subsystem

  // other codes through 15 reserved for system use

  public static final short LOG_LOCAL0 = (16<<3); // reserved for local use
  public static final short LOG_LOCAL1 = (17<<3); // reserved for local use
  public static final short LOG_LOCAL2 = (18<<3); // reserved for local use
  public static final short LOG_LOCAL3 = (19<<3); // reserved for local use
  public static final short LOG_LOCAL4 = (20<<3); // reserved for local use
  public static final short LOG_LOCAL5 = (21<<3); // reserved for local use
  public static final short LOG_LOCAL6 = (22<<3); // reserved for local use
  public static final short LOG_LOCAL7 = (23<<3); // reserved for local use

  public static final short LOG_ILLEGAL_F = -1; // error returned by translateFacility

  public static final short LOG_NFACILITIES = 24;     // maximum number of facilities
  public static final short LOG_FACMASK     = 0x03f8; // mask to extract facility part

  // Priorities (these are ordered)

  public static final byte LOG_EMERG   = 0; // system is unusable
  public static final byte LOG_ALERT   = 1; // action must be taken immediately
  public static final byte LOG_CRIT    = 2; // critical conditions
  public static final byte LOG_ERR     = 3; // error conditions
  public static final byte LOG_WARNING = 4; // warning conditions
  public static final byte LOG_NOTICE  = 5; // normal but signification condition
  public static final byte LOG_INFO    = 6; // informational
  public static final byte LOG_DEBUG   = 7; // debug-level messages

  public static final byte LOG_ILLEGAL_P = -1; // error returned by translatePriority

  public static final byte LOG_PRIMASK = 0x07; // mask to extract priority
                                               //  part (internal)

  // Option flags for openlog.
  //
  //   LOG_ODELAY no longer does anything; LOG_NDELAY is the
  //   inverse of what it used to be.
  //
  //   LOG_NOWAIT does nothing

  public static final byte LOG_PID    = 0x01; // log the pid with each message
                                              //   SORRY, java version shows
                                              //   only thread name there
  public static final byte LOG_CONS   = 0x02; // log on the console if errors
                                              //  in sending
  public static final byte LOG_ODELAY = 0x04; // delay open until syslog() is called
  public static final byte LOG_NDELAY = 0x08; // don't delay open
  public static final byte LOG_NOWAIT = 0x10; // if forking to log on console,
                                              //  don't wait()
  public static final byte LOG_PERROR = 0x20; // log to standard error output
                                              //  as well to the system log

  public static final byte LOG_ILLEGAL_O = -1; // error returned by translateOptions

  // -------------------------------------------------------------------------

  protected String log_host = "localhost";
  protected String ident = null;
  protected byte logopt = 0;
  protected short facility = LOG_USER;
  protected byte mask = LOG_PRIMASK;

  private int open_try = 0;
  private static final int MAX_TRY = 2;
  private Exception exception = null;

  protected String buf = new String();

  protected String file_name = null;
  protected DatagramSocket socket = null;

  public static Syslog log = null;

  // translators

  public static final short translateFacility( String facility )
  {
    if( facility.equals( "KERN"   ) ) return LOG_KERN;
    if( facility.equals( "USER"   ) ) return LOG_USER;
    if( facility.equals( "MAIL"   ) ) return LOG_MAIL;
    if( facility.equals( "DAEMON" ) ) return LOG_DAEMON;
    if( facility.equals( "AUTH"   ) ) return LOG_AUTH;
    if( facility.equals( "SYSLOG" ) ) return LOG_SYSLOG;
    if( facility.equals( "LPR"    ) ) return LOG_LPR;
    if( facility.equals( "NEWS"   ) ) return LOG_NEWS;
    if( facility.equals( "UUCP"   ) ) return LOG_UUCP;
    if( facility.equals( "CRON"   ) ) return LOG_CRON;
    if( facility.equals( "LOCAL0" ) ) return LOG_LOCAL0;
    if( facility.equals( "LOCAL1" ) ) return LOG_LOCAL1;
    if( facility.equals( "LOCAL2" ) ) return LOG_LOCAL2;
    if( facility.equals( "LOCAL3" ) ) return LOG_LOCAL3;
    if( facility.equals( "LOCAL4" ) ) return LOG_LOCAL4;
    if( facility.equals( "LOCAL5" ) ) return LOG_LOCAL5;
    if( facility.equals( "LOCAL6" ) ) return LOG_LOCAL6;
    if( facility.equals( "LOCAL7" ) ) return LOG_LOCAL7;

    return LOG_ILLEGAL_F;
  }

  public static final byte translatePriority( String priority )
  {
    if( priority.equals( "EMERG"   ) ) return LOG_EMERG;
    if( priority.equals( "ALERT"   ) ) return LOG_ALERT;
    if( priority.equals( "CRIT"    ) ) return LOG_CRIT;
    if( priority.equals( "ERR"     ) ) return LOG_ERR;
    if( priority.equals( "WARNING" ) ) return LOG_WARNING;
    if( priority.equals( "NOTICE"  ) ) return LOG_NOTICE;
    if( priority.equals( "INFO"    ) ) return LOG_INFO;
    if( priority.equals( "DEBUG"   ) ) return LOG_DEBUG;

    return LOG_ILLEGAL_P;
  }

  public static final byte translateOptions( String options )
  {
    StringTokenizer st = new StringTokenizer( options, "," );
    byte ret = 0;

    for( int i = 0; st.hasMoreTokens(); i++ )
    {
      String s = st.nextToken();

           if( s.equals( "PID"    ) ) ret |= LOG_PID;
      else if( s.equals( "CONS"   ) ) ret |= LOG_CONS;
      else if( s.equals( "ODELAY" ) ) ret |= LOG_ODELAY;
      else if( s.equals( "NDELAY" ) ) ret |= LOG_NDELAY;
      else if( s.equals( "NOWAIT" ) ) ret |= LOG_NOWAIT;
      else if( s.equals( "PERROR" ) ) ret |= LOG_PERROR;
      else                            return LOG_ILLEGAL_O;
    }

    return ret;
  }

  // arguments to setlogmask

  public static final short LOG_MASK( short pri )
    { return (short)(1 << pri); }

  public static final short LOG_UPTO( short pri )
    { return (short)((1 << (pri+1)) - 1); }

  public static final short LOG_PRI( short pri )
    { return (short)(pri & LOG_PRIMASK); }

  // constructors

  public Syslog( String ident, byte logopt, short facility )
  {
    this( ident, logopt, facility, null );
  }

  public Syslog( String ident, int logopt, short facility )
  {
    this( ident, (byte)logopt, facility, null );
  }

  public Syslog( String ident, int logopt, short facility, String log_host )
  {
    this( ident, (byte)logopt, facility, log_host );
  }

  public Syslog( String ident, byte logopt, short facility, String log_host )
  {
    this.ident    = ident;
    this.logopt   = logopt;

    if( log_host != null )
      this.log_host = log_host;

    if( facility != 0 && (facility & ~LOG_FACMASK) == 0 )
      this.facility = facility;

    String sep = System.getProperty( "file.separator" );
    file_name = new String( sep.equals( "/" ) ? "/dev/console" : "con" );

    if( (logopt & LOG_NDELAY) == LOG_NDELAY )
      openlog();

    log = this;
  }

  // openlog() for internal usage

  private void openlog()
  {
    if( open_try < MAX_TRY )
    {
      ++open_try;

      try
      {
        socket = new DatagramSocket();
        socket.connect( InetAddress.getByName( log_host ), 514 );
      }
      catch( SocketException e ) { exception = e; }
      catch( UnknownHostException e ) { exception = e; }
    }
  }

  // user interface functions

  public void closelog()
  {
    if( socket != null )
    {
      socket.close();
      socket = null;
    }
  }

  public byte setlogmask( short priority )
  {
    return setlogmask( (byte)priority );
  }

  public byte setlogmask( int priority )
  {
    return setlogmask( (byte)priority );
  }

  public byte setlogmask( byte priority )
  {
    byte old = mask;

    if( priority != 0 )
      mask = priority;

    return old;
  }

  public byte getMask() { return mask; }

  public DatagramSocket getSocket() { return socket; }

  public Exception getException() { return exception; }

  // logging functions

  public void syslog( int priority, String par_msg )
  {
    syslog( (short)priority, par_msg );
  }

  public boolean need( short priority )
  {
    return (LOG_MASK( LOG_PRI(priority) ) & mask) != 0;
  }

  public void syslog( short priority, String par_msg )
  {
    synchronized( this ) {
    if( (priority & ~(LOG_PRIMASK|LOG_FACMASK)) != 0 )
    {
      syslog( LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID|LOG_USER,
              Thread.currentThread().getName()+
                ": syslog: unknown facility/priority: "+
                Integer.toHexString( priority ) );
      priority &= LOG_PRIMASK|LOG_FACMASK;
    }

    if( !need( priority ) )
      return;

    if( (priority & LOG_FACMASK) == 0 )
      priority |= facility;

    String msg = new String();
    boolean any_add = false;

    if( ident != null )
    {
      msg += ident;
      any_add = true;
    }

    if( (logopt & LOG_PID) == LOG_PID )
    {
      msg += "["+Thread.currentThread().getName()+"]";
      any_add = true;
    }

    if( any_add )
      msg += ": "+par_msg;
    else
      msg += par_msg;

    if( (logopt & LOG_PERROR) == LOG_PERROR )
      System.err.print( msg+"\r\n" );

    if( socket == null )
      openlog();

    if( socket != null )
    {
      String msg1 = new String( "<"+priority+">"+msg );
      byte[] buf = msg1.getBytes();
      DatagramPacket p = new DatagramPacket( buf, buf.length );

      try
      {
        socket.send( p );
        return;
      }
      catch( IOException e )
      {
      }
    }

    if( (logopt & LOG_CONS) == LOG_CONS )
      try
      {
        PrintWriter file  = new PrintWriter( new FileOutputStream( file_name ) );

        file.print( msg+"\r\n" );
        file.close();
        file = null;
      } 
      catch( FileNotFoundException e ) {}
    }
  }

  // PrintWriter implementation

  public void write( int b ) throws IOException
  {
    char ch = (char)(b&0xff);

    switch( ch )
    {
    case '\n':
      flush();
      break;

    case '\r':
      break;

    case '\t':
      buf += ' ';
      break;

    default:
      buf += ch;
    }
  }

  public void close() throws IOException
  {
    flush();
  }

  protected void finalize() throws Throwable
  {
    flush();
    closelog();
  }

  public void flush() throws IOException
  {
    if( buf.length() != 0 )
    {
      syslog( Syslog.LOG_CRIT, buf );
      buf = new String();
    }
  }

  // kewl exception tracer ;-)

  public void print_exception( Throwable e )
  {
    if( e instanceof DoneException )                      // Sorry, not for you
      syslog( Syslog.LOG_CRIT, "Abort: "+e.toString() );  // just kill this if()
    else                                                  //   up to here
    {
      PrintWriter prt = new PrintWriter( this, true );
      String errmsg = new String( "FATAL: "+Thread.currentThread().getName()+
                                  " Exception " );

      prt.print( errmsg );
      e.printStackTrace( prt );
      prt.flush();

      System.err.print( errmsg );
      e.printStackTrace();
    }
  }

/*
  public static void main( String[] a )
  {
    String m = new String();

    for( int i=0; i<a.length; i++ )
      m += a[i]+" ";

    Syslog log = new Syslog( "test Syslog", translateOptions( "CONS,PID" ),
                             translateFacility( "DAEMON" ) );
    Throwable e = new Throwable();

    log.syslog( LOG_ALERT, "the test: "+m );
    e.fillInStackTrace();
    log.print_exception( e );
  }
*/
}