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/* xcxmdm.c -- XMODEM Protocol module for XC
This file uses 4-character tabstops
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <setjmp.h>
#include "xc.h"
#define CPMEOF 032 /* ^Z */
#define WANTCRC 'C'
#define OK 0
#define TIMEOUT -1 /* -1 is returned by readbyte() upon timeout */
#define ERROR -2
#define WCEOT -3
#define RETRYMAX 10
#define SECSIZ 128
#define Resume_Not_Allowed 1
/* crc_xmodem_tab calculated by Mark G. Mendel, Network Systems Corporation */
ushort crc_xmodem_tab[256] = {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
};
short crcheck = TRUE; /* CRC check enabled? */
static FILE *xfp; /* buffered file pointer */
static short firstsec, /* first sector of file or not? */
textmode, /* Text translations enabled? */
save_crc; /* Saved crcheck value */
static char wcbuf[SECSIZ]; /* Ward Christensen sector buffer */
static ushort Updcrc();
static jmp_buf our_env;
static RETSIGTYPE (*oldvec)();
/* send 10 CAN's to try to get the other end to shut up */
static void
canit()
{
int i;
for(i = 0; i < 20; i++)
sendbyte(CAN);
}
static RETSIGTYPE
xmsigint(junk)
int junk;
{
show_abort();
signal(SIGINT, SIG_IGN); /* Ignore subsequent DEL's */
canit(); /* Abort the transmission */
longjmp(our_env,1);
}
/* fill the CP/M sector buffer from the UNIX file
do text adjustments if necessary
return 1 if more sectors are to be read, or 0 if this is the last
*/
static
getsec()
{
int i;
register c;
i = 0;
while(i < SECSIZ && (c = getc(xfp)) != EOF){
if (textmode && c == '\n'){
wcbuf[i++] = '\r';
if (i >= SECSIZ){ /* handle a newline on the last byte */
ungetc(c, xfp); /* of the sector */
return(1);
}
}
wcbuf[i++] = c;
}
/* make sure that an extra blank sector is not sent */
if (c != EOF && (c = getc(xfp)) != EOF){
ungetc(c, xfp);
return(1);
}
/* fill up the last sector with ^Z's if text mode or 0's if binary mode */
while(i < SECSIZ)
wcbuf[i++] = textmode ? CPMEOF : '\0';
return(0);
}
/* wcgetsec() inputs an XMODEM "sector".
This routine returns the sector number encountered, or ERROR if a valid
sector is not received or CAN received; or WCEOT if EOT sector.
Maxtime is the timeout for the first character, set to 6 seconds for
retries. No ACK is sent if the sector is received ok. This must be
done by the caller when it is ready to receive the next sector.
*/
static
wcgetsec(maxtime)
unsigned maxtime;
{
register ushort oldcrc;
register checksum, j, c;
int sectcurr, sectcomp, attempts;
for(attempts = 0; attempts < RETRYMAX; attempts++){
do {
c = readbyte(maxtime);
} while(c != SOH && c != EOT && c != CAN && c != TIMEOUT);
switch(c){
case SOH:
sectcurr = readbyte(3);
sectcomp = readbyte(3);
if ((sectcurr + sectcomp) == 0xff){
oldcrc = checksum = 0;
for(j = 0; j < SECSIZ; j++){
if ((c = readbyte(3)) == TIMEOUT)
goto timeout;
wcbuf[j] = c;
if (crcheck)
oldcrc = Updcrc(c, oldcrc);
else
checksum += c;
}
if ((c = readbyte(3)) < 0)
goto timeout;
if (crcheck){
oldcrc = Updcrc(c, oldcrc);
if ((c = readbyte(3)) == TIMEOUT)
goto timeout;
if (Updcrc(c, oldcrc)){
S2("CRC error");
break;
}
}
else if (((checksum - c) & 0xff) != 0){
S2("Checksum error");
break;
}
firstsec = FALSE;
return(sectcurr);
}
else
sprintf(Msg, "Sector number garbled 0%03o 0%03o",
sectcurr, sectcomp);
S2(Msg);
break;
case EOT:
if (readbyte(3) == TIMEOUT)
return(WCEOT);
break;
case CAN:
S2("Sender CANcelled");
return(ERROR);
case TIMEOUT:
if (firstsec)
break;
timeout:
S2("Timeout");
break;
}
S2("Trying again on this sector");
purge();
if (firstsec)
sendbyte(crcheck ? WANTCRC : NAK);
else
maxtime = 6,
sendbyte(NAK);
}
S2("Retry count exceeded");
canit();
return(ERROR);
}
static
putsec()
{
int i;
register c;
for(i = 0; i < SECSIZ; i++){
c = wcbuf[i];
if (textmode){
if (c == CPMEOF)
return(1);
if (c == '\r')
continue;
}
putc(c, xfp);
}
return(0);
}
/* Receive a file using XMODEM protocol */
static
wcrx()
{
register sendchar, sectnum, sectcurr;
strcpy(Name, word);
if (!(xfp=QueryCreate(Resume_Not_Allowed)))
return(ERROR);
firstsec = TRUE;
sectnum = 0;
sendchar = crcheck ? WANTCRC : NAK;
fputc('\r',tfp),
fputc('\n', tfp);
S1("Sync...");
while(TRUE){
purge();
sendbyte(sendchar);
sectcurr = wcgetsec(6);
if (sectcurr == ((sectnum + 1) & 0xff)){
sectnum++;
putsec();
fprintf(tfp,"Received sector #%d\r", sectnum);
sendchar = ACK;
continue;
}
if (sectcurr == (sectnum & 0xff)){
sprintf(Msg, "Received duplicate sector #%d", sectnum);
S2(Msg);
sendchar = ACK;
continue;
}
fclose(xfp);
if (sectcurr == WCEOT){
S1("File received OK");
sendbyte(ACK);
return(OK);
}
if (sectcurr == ERROR)
return(ERROR);
sprintf(Msg, "Sync error ... expected %d(%d), got %d",
(sectnum + 1) & 0xff, sectnum, sectcurr);
S;
return(ERROR);
}
}
/* wcputsec outputs a Ward Christensen type sector.
it returns OK or ERROR
*/
static
wcputsec(sectnum)
int sectnum;
{
register ushort oldcrc;
register checksum, j, c, attempts;
oldcrc = checksum = 0;
for(j = 0; j < SECSIZ; j++)
c = wcbuf[j],
oldcrc = Updcrc(c, oldcrc),
checksum += c;
oldcrc = Updcrc(0, Updcrc(0, oldcrc));
for(attempts = 0; attempts < RETRYMAX; attempts++){
sendbyte(SOH);
sendbyte(sectnum);
sendbyte(-sectnum - 1);
for(j = 0; j < SECSIZ; j++)
sendbyte(wcbuf[j]);
purge();
if (crcheck){
sendbyte((int) (oldcrc >> 8));
sendbyte((int) oldcrc);
}
else
sendbyte(checksum);
switch(c = readbyte(10)){
case CAN:
S2("Receiver CANcelled");
return(ERROR);
case ACK:
firstsec = FALSE;
return(OK);
case NAK:
S2("Got a NAK on sector acknowledge");
break;
case TIMEOUT:
S2("Timeout on sector acknowledge");
break;
default:
sprintf(Msg, "Got 0%03o for sector acknowledge", c);
S2(Msg);
do {
if ((c = readbyte(3)) == CAN){
S2("Receiver CANcelled");
return(ERROR);
}
} while(c != TIMEOUT);
if (firstsec)
crcheck = (c == WANTCRC);
break;
}
}
S2("Retry count exceeded");
return(ERROR);
}
/* Transmit a file using XMODEM protocol */
static
wctx()
{
register sectnum, eoflg, c, attempts;
if (!(xfp = fopen(word, "r"))){
sprintf(Msg, "Can't open '%s'", word);
S;
return(ERROR);
}
firstsec = TRUE;
attempts = 0;
S1("Sync...");
while((c = readbyte(30)) != NAK && c != WANTCRC && c != CAN)
if (c == TIMEOUT && ++attempts > RETRYMAX){
S1("Receiver not responding");
fclose(xfp);
return(ERROR);
}
if (c == CAN){
S1("Receiver CANcelled");
fclose(xfp);
return(ERROR);
}
crcheck = (c == WANTCRC);
sprintf(Msg,"%s error checking requested", crcheck ? "CRC-16" : "Checksum");
S;
sectnum = 1;
do {
eoflg = getsec();
fprintf(tfp,"Transmitting sector #%d\r", sectnum);
if (wcputsec(sectnum) == ERROR){
fclose(xfp);
return(ERROR);
}
sectnum++;
} while(eoflg);
fclose(xfp);
attempts = 0;
sendbyte(EOT);
while(readbyte(5) != ACK && attempts++ < RETRYMAX)
sendbyte(EOT);
if (attempts >= RETRYMAX){
S1("Receiver not responding to completion");
return(ERROR);
}
S1("Transmission complete");
return(OK);
}
/* update the cyclic redundancy check value */
static ushort
Updcrc(c, crc)
register c;
register unsigned crc;
{
int i;
for(i = 0; i < 8; i++){
if (crc & 0x8000)
crc <<= 1,
crc += (((c <<= 1) & 0400) != 0),
crc ^= 0x1021;
else
crc <<= 1,
crc += (((c <<= 1) & 0400) != 0);
}
return(crc);
}
static
setmode(c)
int c;
{
switch(tolower(c)){
case 't':
textmode = TRUE;
break;
case 'b':
textmode = FALSE;
case ' ':
break;
default:
return FAILURE;
}
sprintf(Msg, "XMODEM %s file transfer mode", textmode ? "Text" : "Binary");
S;
return SUCCESS;
}
/* Put received WC sector into a UNIX file
using text translations if neccesary.
*/
void
xreceive(c)
int c;
{
save_crc = crcheck;
oldvec = signal(SIGINT, xmsigint);
if (setmode(c)){
if (!setjmp(our_env)){
/* crcheck = 0xff; */
sprintf(Msg, "Ready to receive single file %s", word);
S;
if (wcrx() == ERROR)
canit();
return;
}
}
signal(SIGINT, oldvec);
crcheck = save_crc;
}
void
xsend(c)
int c;
{
save_crc = crcheck;
oldvec = signal(SIGINT, xmsigint);
if (setmode(c)){
if (!setjmp(our_env)){
/* crcheck = 0xff; */
if (wctx() == ERROR){
sprintf(Msg, "Error transmitting file %s", word);
S;
return;
}
}
}
signal(SIGINT, oldvec);
crcheck = save_crc;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.