zmodemr.c

Gcomm is a serial communications program similar to seyon, but more modern, and easier to use. Works

#ifndef lint
static const char rcsid[] = "$Id: zmodemr.c,v 1.1.1.1 2001/03/08 00:01:48 efalk Exp $" ;
#endif

/*
 * Copyright (c) 1995 by Edward A. Falk
 */


/**********
 *
 *
 *	@@@@@  @   @   @@@   @@@@   @@@@@  @   @  @@@@   
 *	   @   @@ @@  @   @  @   @  @      @@ @@  @   @  
 *	  @    @ @ @  @   @  @   @  @@@    @ @ @  @@@@   
 *	 @     @ @ @  @   @  @   @  @      @ @ @  @  @   
 *	@@@@@  @ @ @   @@@   @@@@   @@@@@  @ @ @  @   @  
 *
 *	ZMODEMR - receive side of zmodem protocol
 *
 * receive side of zmodem protocol
 *
 * This code is designed to be called from inside a larger
 * program, so it is implemented as a state machine where
 * practical.
 *
 * functions:
 *
 *	ZmodemRInit(ZModem *info)
 *		Initiate a connection
 *
 *	ZmodemRAbort(ZModem *info)
 *		abort transfer
 *
 * all functions return 0 on success, 1 on failure
 *
 *
 *	Edward A. Falk
 *
 *	January, 1995
 *
 *
 *
 **********/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include "zmodem.h"
#include "crctab.h"

extern	int	errno ;

extern	int	ZWriteFile(u_char *buffer, int len, FILE *, ZModem *);
extern	int	ZCloseFile(ZModem *info) ;
extern	void	ZFlowControl(int onoff, ZModem *info) ;

static	u_char	zeros[4] = {0,0,0,0} ;





int
ZmodemRInit(ZModem *info)
{
	info->packetCount = 0 ;
	info->offset = 0 ;
	info->errCount = 0 ;
	info->escCtrl = info->escHibit = info->atSign = info->escape = 0 ;
	info->InputState = Idle ;
	info->canCount = info->chrCount = 0 ;
	info->filename = NULL ;
	info->interrupt = 0 ;
	info->waitflag = 0 ;
	info->attn = NULL ;
	info->file = NULL ;

	info->buffer = (u_char *)malloc(8192) ;

	info->state = RStart ;
	info->timeoutCount = 0 ;

	ZIFlush(info) ;

	/* Don't send ZRINIT right away, there might be a ZRQINIT in
	 * the input buffer.  Instead, set timeout to zero and return.
	 * This will allow ZmodemRcv() to check the input stream first.
	 * If nothing found, a ZRINIT will be sent immediately.
	 */
	info->timeout = 0 ;

	zmodemlog("ZmodemRInit[%s]: flush input, new state = RStart\n",
	    sname(info)) ;

	return 0 ;
}

int
YmodemRInit(ZModem *info)
{
	info->errCount = 0 ;
	info->InputState = Yrcv ;
	info->canCount = info->chrCount = 0 ;
	info->noiseCount = 0 ;
	info->filename = NULL ;
	info->file = NULL ;

	if( info->buffer == NULL )
	  info->buffer = (u_char *)malloc(1024) ;

	info->state = YRStart ;
	info->packetCount = -1 ;
	info->timeoutCount = 0 ;
	info->timeout = 10 ;
	info->offset = 0 ;

	ZIFlush(info) ;

	return ZXmitStr((u_char *)"C", 1, info) ;
}





extern	int	ZPF() ;
extern	int	Ignore() ;
extern	int	GotCommand() ;
extern	int	GotStderr() ;

	int	SendRinit() ;
static	int	GotSinit() ;
static	int	GotFile() ;
static	int	GotFin() ;
static	int	GotData() ;
static	int	GotEof() ;
static	int	GotFreecnt() ;
static	int	GotFileCrc() ;
	int	ResendCrcReq() ;
	int	ResendRpos() ;

		/* sent ZRINIT, waiting for ZSINIT or ZFILE */
	StateTable	RStartOps[] = {
	  {ZSINIT,GotSinit,0,1,RSinitWait},	/* SINIT, wait for attn str */
	  {ZFILE,GotFile,0,0,RFileName},	/* FILE, wait for filename */
	  {ZRQINIT,SendRinit,0,1,RStart},	/* sender confused, resend */
	  {ZFIN,GotFin,1,0,RFinish},		/* sender shutting down */
	  {ZNAK,SendRinit,1,0,RStart},		/* RINIT was bad, resend */
#ifdef	TODO
	  {ZCOMPL,f,1,1,s},
#endif	/* TODO */
	  {ZFREECNT,GotFreecnt,0,0,RStart},	/* sender wants free space */
	  {ZCOMMAND,GotCommand,0,0,CommandData}, /* sender wants command */
	  {ZSTDERR,GotStderr,0,0,StderrData},	/* sender wants to send msg */
	  {99,ZPF,0,0,RStart},			/* anything else is an error */
	} ;

	StateTable	RSinitWaitOps[] = {	/* waiting for data */
	  {99,ZPF,0,0,RSinitWait},
	} ;

	StateTable	RFileNameOps[] = {	/* waiting for file name */
	  {99,ZPF,0,0,RFileName},
	} ;

	StateTable	RCrcOps[] = {		/* waiting for CRC */
	  {ZCRC,GotFileCrc,0,0,RFile},		  /* sender sent it */
	  {ZNAK,ResendCrcReq,0,0,RCrc},		  /* ZCRC was bad, resend */
	  {ZRQINIT,SendRinit,1,1,RStart},	  /* sender confused, restart */
	  {ZFIN,GotFin,1,1,RFinish},		  /* sender signing off */
	  {99,ZPF,0,0,RCrc},
	} ;

	StateTable	RFileOps[] = {		/* waiting for ZDATA */
	  {ZDATA,GotData,0,0,RData},		  /* got it */
	  {ZNAK,ResendRpos,0,0,RFile},		  /* ZRPOS was bad, resend */
	  {ZEOF,GotEof,0,0,RStart},		  /* end of file */
	  {ZRQINIT,SendRinit,1,1,RStart},	  /* sender confused, restart */
	  {ZFILE,ResendRpos,0,0,RFile},		  /* ZRPOS was bad, resend */
	  {ZFIN,GotFin,1,1,RFinish},		  /* sender signing off */
	  {99,ZPF,0,0,RFile},
	} ;

	/* waiting for data, but a packet could possibly arrive due
	 * to error recovery or something
	 */
	StateTable	RDataOps[] = {
	  {ZRQINIT,SendRinit,1,1,RStart},	/* sender confused, restart */
	  {ZFILE,GotFile,0,1,RFileName},	/* start a new file (??) */
	  {ZNAK,ResendRpos,1,1,RFile},		/* ZRPOS was bad, resend */
	  {ZFIN,GotFin,1,1,RFinish},		/* sender signing off */
	  {ZDATA,GotData,0,1,RData},		/* file data follows */
	  {ZEOF,GotEof,1,1,RStart},		/* end of file */
	  {99,ZPF,0,0,RData},
	} ;

	/* here if we've sent ZFERR or ZABORT.  Waiting for ZFIN */

	StateTable	RFinishOps[] = {
	  {ZRQINIT,SendRinit,1,1,RStart},	/* sender confused, restart */
	  {ZFILE,GotFile,1,1,RFileName},	/* start a new file */
	  {ZNAK,GotFin,1,1,RFinish},		/* resend ZFIN */
	  {ZFIN,GotFin,1,1,RFinish},		/* sender signing off */
	  {99,ZPF,0,0,RFinish},
	} ;




extern	char	*hdrnames[] ;

extern	int	dataSetup() ;


	/* RECEIVE-RELATED STUFF BELOW HERE */


	/* resend ZRINIT header in response to ZRQINIT or ZNAK header */

int
SendRinit( register ZModem *info )
{
	u_char	dbuf[4] ;

#ifdef	COMMENT
	if( info->timeoutCount >= 5 )
	  /* TODO: switch to Ymodem */
#endif	/* COMMENT */

	zmodemlog("SendRinit[%s]: send ZRINIT\n", sname(info)) ;

	info->timeout = ResponseTime ;
	dbuf[0] = info->bufsize&0xff ;
	dbuf[1] = (info->bufsize>>8)&0xff ;
	dbuf[2] = 0 ;
	dbuf[3] = info->zrinitflags ;
	return ZXmitHdrHex(ZRINIT, dbuf, info) ;
}



	/* received a ZSINIT header in response to ZRINIT */

static	int
GotSinit( register ZModem *info )
{
	zmodemlog("GotSinit[%s]: call dataSetup\n", sname(info)) ;

	info->zsinitflags = info->hdrData[4] ;
	info->escCtrl = info->zsinitflags & TESCCTL ;
	info->escHibit = info->zsinitflags & TESC8 ;
	ZFlowControl(1, info) ;
	return dataSetup(info) ;
}

	/* received rest of ZSINIT packet */

int
GotSinitData( register ZModem *info, int crcGood )
{
	info->InputState = Idle ;
	info->chrCount=0 ;
	info->state = RStart ;

	zmodemlog("GotSinitData[%s]: crcGood=%d\n", sname(info), crcGood) ;

	if( !crcGood )
	  return ZXmitHdrHex(ZNAK, zeros, info) ;

	if( info->attn != NULL )
	  free(info->attn) ;
	info->attn = NULL ;
	if( info->buffer[0] != '\0' )
	  info->attn = strdup((char *)info->buffer) ;
	return ZXmitHdrHex(ZACK, ZEnc4(SerialNo), info) ;
}


	/* got ZFILE.  Cache flags and set up to receive filename */

static	int
GotFile( register ZModem *info )
{
	zmodemlog("GotFile[%s]: call dataSetup\n", sname(info)) ;

	info->errCount = 0 ;
	info->f0 = info->hdrData[4] ;
	info->f1 = info->hdrData[3] ;
	info->f2 = info->hdrData[2] ;
	info->f3 = info->hdrData[1] ;
	return dataSetup(info) ;
}


	/* utility: see if ZOpenFile wants this file, and if
	 * so, request it from sender.
	 */

static	int
requestFile( register ZModem *info, u_long crc )
{
	info->file = ZOpenFile((char *)info->buffer, crc, info) ;

	if( info->file == NULL ) {
	  zmodemlog("requestFile[%s]: send ZSKIP\n", sname(info)) ;

	  info->state = RStart ;
	  ZStatus(FileSkip, 0, info->filename) ;
	  return ZXmitHdrHex(ZSKIP, zeros, info) ;
	}
	else {
	  zmodemlog("requestFile[%s]: send ZRPOS(%ld)\n",
	    sname(info), info->offset) ;
	  info->offset = info->f0 == ZCRESUM ? ftell(info->file) : 0 ;
	  info->state = RFile ;
	  ZStatus(FileBegin, 0, info->filename) ;
	  return ZXmitHdrHex(ZRPOS, ZEnc4(info->offset), info) ;
	}
}


	/* parse filename info. */

static	void
parseFileName( register ZModem *info, char *fileinfo )
{
	char	*ptr ;
	int	serial=0 ;

	info->len = info->mode = info->filesRem =
		info->bytesRem = info->fileType = 0 ;
	ptr = fileinfo + strlen(fileinfo) + 1 ;
	if( info->filename != NULL )
	  free(info->filename) ;
	info->filename = strdup(fileinfo) ;
	sscanf(ptr, "%d %lo %o %o %d %d %d", &info->len, &info->date,
	    &info->mode, &serial, &info->filesRem, &info->bytesRem,
	    &info->fileType) ;
}


	/* got filename.  Parse arguments from it and execute
	 * policy function ZOpenFile(), provided by caller
	 */

int
GotFileName( register ZModem *info, int crcGood )
{
	info->InputState = Idle ;
	info->chrCount=0 ;

	if( !crcGood ) {
	zmodemlog("GotFileName[%s]: bad crc, send ZNAK\n", sname(info)) ;
	  info->state = RStart ;
	  return ZXmitHdrHex(ZNAK, zeros, info) ;
	}

	parseFileName(info, (char *)info->buffer) ;

	if( (info->f1 & ZMMASK) == ZMCRC ) {
	  info->state = RCrc ;
	  return ZXmitHdrHex(ZCRC, zeros, info) ;
	}

	zmodemlog("GotFileName[%s]: good crc, call requestFile\n",
		sname(info)) ;
	info->state = RFile ;
	return requestFile(info,0) ;
}


int