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The source code/* * Copyright 1999-2004 The Apache Software Foundation * * 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 org.apache.jk.common; import java.io.IOException; import org.apache.jk.core.Msg; import org.apache.tomcat.util.buf.ByteChunk; import org.apache.tomcat.util.buf.MessageBytes; /** * A single packet for communication between the web server and the * container. Designed to be reused many times with no creation of * garbage. Understands the format of data types for these packets. * Can be used (somewhat confusingly) for both incoming and outgoing * packets. * * @see Ajp14/Ajp13Packet * * @author Henri Gomez [hgomez@apache.org] * @author Dan Milstein [danmil@shore.net] * @author Keith Wannamaker [Keith@Wannamaker.org] * @author Kevin Seguin * @author Costin Manolache */ public class MsgAjp extends Msg { private static org.apache.commons.logging.Log log= org.apache.commons.logging.LogFactory.getLog( MsgAjp.class ); // that's the original buffer size in ajp13 - otherwise we'll get interoperability problems. private byte buf[]=new byte[8*1024]; // The current read or write position in the buffer private int pos; /** * This actually means different things depending on whether the * packet is read or write. For read, it's the length of the * payload (excluding the header). For write, it's the length of * the packet as a whole (counting the header). Oh, well. */ private int len; /** * Prepare this packet for accumulating a message from the container to * the web server. Set the write position to just after the header * (but leave the length unwritten, because it is as yet unknown). */ public void reset() { len = 4; pos = 4; } /** * For a packet to be sent to the web server, finish the process of * accumulating data and write the length of the data payload into * the header. */ public void end() { len=pos; int dLen=len-4; buf[0] = (byte)0x41; buf[1] = (byte)0x42; buf[2]= (byte)((dLen>>>8 ) & 0xFF ); buf[3] = (byte)(dLen & 0xFF); } public byte[] getBuffer() { return buf; } public int getLen() { return len; } // ============ Data Writing Methods =================== /** * Add an int. * * @param val The integer to write. */ public void appendInt( int val ) { buf[pos++] = (byte) ((val >>> 8) & 0xFF); buf[pos++] = (byte) (val & 0xFF); } public void appendByte( int val ) { buf[pos++] = (byte)val; } public void appendLongInt( int val ) { buf[pos++] = (byte) ((val >>> 24) & 0xFF); buf[pos++] = (byte) ((val >>> 16) & 0xFF); buf[pos++] = (byte) ((val >>> 8) & 0xFF); buf[pos++] = (byte) (val & 0xFF); } /** * Write a String out at the current write position. Strings are * encoded with the length in two bytes first, then the string, and * then a terminating \0 (which is not included in the * encoded length). The terminator is for the convenience of the C * code, where it saves a round of copying. A null string is * encoded as a string with length 0. */ public void appendBytes(MessageBytes mb) throws IOException { if(mb==null || mb.isNull() ) { appendInt( 0); appendByte(0); return; } // XXX Convert !! ByteChunk bc= mb.getByteChunk(); appendByteChunk(bc); } public void appendByteChunk(ByteChunk bc) throws IOException { if(bc==null) { log.error("appendByteChunk() null"); appendInt( 0); appendByte(0); return; } byte[] bytes = bc.getBytes(); int start=bc.getStart(); appendInt( bc.getLength() ); cpBytes(bytes, start, bc.getLength()); appendByte(0); } /** * Copy a chunk of bytes into the packet, starting at the current * write position. The chunk of bytes is encoded with the length * in two bytes first, then the data itself, and finally a * terminating \0 (which is not included in the encoded * length). * * @param b The array from which to copy bytes. * @param off The offset into the array at which to start copying * @param len The number of bytes to copy. */ public void appendBytes( byte b[], int off, int numBytes ) { appendInt( numBytes ); cpBytes( b, off, numBytes ); appendByte(0); } private void cpBytes( byte b[], int off, int numBytes ) { if( pos + numBytes >= buf.length ) { log.error("Buffer overflow: buffer.len=" + buf.length + " pos=" + pos + " data=" + numBytes ); dump("Overflow/coBytes"); log.error( "Overflow ", new Throwable()); return; } System.arraycopy( b, off, buf, pos, numBytes); pos += numBytes; // buf[pos + numBytes] = 0; // Terminating \0 } // ============ Data Reading Methods =================== /** * Read an integer from packet, and advance the read position past * it. Integers are encoded as two unsigned bytes with the * high-order byte first, and, as far as I can tell, in * little-endian order within each byte. */ public int getInt() { int b1 = buf[pos++] & 0xFF; // No swap, Java order int b2 = buf[pos++] & 0xFF; return (b1<<8) + b2; } public int peekInt() { int b1 = buf[pos] & 0xFF; // No swap, Java order int b2 = buf[pos+1] & 0xFF; return (b1<<8) + b2; } public byte getByte() { byte res = buf[pos++]; return res; } public byte peekByte() { byte res = buf[pos]; return res; } public void getBytes(MessageBytes mb) { int length = getInt(); if( (length == 0xFFFF) || (length == -1) ) { mb.setString( null ); return; } mb.setBytes( buf, pos, length ); pos += length; pos++; // Skip the terminating \0 } /** * Copy a chunk of bytes from the packet into an array and advance * the read position past the chunk. See appendBytes() for details * on the encoding. * * @return The number of bytes copied. */ public int getBytes(byte dest[]) { int length = getInt(); if( length > buf.length ) { // XXX Should be if(pos + length > buff.legth)? log.error("getBytes() buffer overflow " + length + " " + buf.length ); } if( (length == 0xFFFF) || (length == -1) ) { log.info("Null string " + length); return 0; } System.arraycopy( buf, pos, dest, 0, length ); pos += length; pos++; // Skip terminating \0 XXX I believe this is wrong but harmless return length; } /** * Read a 32 bits integer from packet, and advance the read position past * it. Integers are encoded as four unsigned bytes with the * high-order byte first, and, as far as I can tell, in * little-endian order within each byte. */ public int getLongInt() { int b1 = buf[pos++] & 0xFF; // No swap, Java order b1 <<= 8; b1 |= (buf[pos++] & 0xFF); b1 <<= 8; b1 |= (buf[pos++] & 0xFF); b1 <<=8; b1 |= (buf[pos++] & 0xFF); return b1; } public int getHeaderLength() { return 4; } public int processHeader() { pos = 0; int mark = getInt(); len = getInt(); if( mark != 0x1234 && mark != 0x4142 ) { // XXX Logging log.error("BAD packet signature " + mark); dump( "In: " ); return -1; } if( log.isDebugEnabled() ) log.debug( "Received " + len + " " + buf[0] ); return len; } public void dump(String msg) { log.debug( msg + ": " + buf + " " + pos +"/" + (len + 4)); int max=pos; if( len + 4 > pos ) max=len+4; if( max >1000 ) max=1000; for( int j=0; j < max; j+=16 ) System.out.println( hexLine( buf, j, len )); } /* -------------------- Utilities -------------------- */ // XXX Move to util package public static String hexLine( byte buf[], int start, int len ) { StringBuffer sb=new StringBuffer(); for( int i=start; i< start+16 ; i++ ) { if( i < len + 4) sb.append( hex( buf[i] ) + " "); else sb.append( " " ); } sb.append(" | "); for( int i=start; i < start+16 && i < len + 4; i++ ) { if( ! Character.isISOControl( (char)buf[i] )) sb.append( new Character((char)buf[i]) ); else sb.append( "." ); } return sb.toString(); } private static String hex( int x ) { // if( x < 0) x=256 + x; String h=Integer.toHexString( x ); if( h.length() == 1 ) h = "0" + h; return h.substring( h.length() - 2 ); } } |
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