char soh = 0x01;
char eot = 0x04;
char ack = 0x06;
char nak = 0x15;
char can = 0x18;
#include "stdio.h"
#include "signal.h"
#include "termio.h"
#include "sys/ioctl.h"
#include "sys/types.h"
#include "sys/stat.h"
struct termio save;
struct termio new;
struct stat statbuf;

int lfproc = 0;
int debug = 0;
FILE *errors;
main(argc, argv)
int argc;
char **argv;
{
	int i,j;
	char buf[130];
	char blocknum = 1;
	char c_blocknum = 254;
	int numread;
	char cksum;
	char inch;
	int alarmfn();
	int kleenex();
	FILE *fp;
	extern char *optarg;
	extern int optind;
	char file[128];

	while ((i = getopt(argc, argv, "tld")) != EOF)
		switch(i) {
		case 'd':
			debug++;
			break;
		case 'l':
		case 't':	/* TEXT files */
			lfproc++;
			break;
		case '?':
			fprintf(stderr, "Usage: %s [-l] file\n", argv[0]);
			kleenex(0);
			break;
		}
	ioctl(1, TCGETA, &save);
	ioctl(1, TCGETA, &new);
	if (debug) errors = fopen("xt.err", "w");
	if (debug && errors == NULL) {
		fprintf(stderr, "Unable to open xt.err for error tracing\n");
		kleenex(1);
	}
	if (debug) setbuf(errors, NULL);
	if (argc == 1 || argc == optind) {
		fprintf(stderr, "Need file name\n");
		kleenex(0);
	}
	strcpy(file, argv[optind]);
	for (i=1; i<20;i++) signal(i, SIG_IGN);
	signal(14, alarmfn);
	signal(3, kleenex);
	signal(1, kleenex);
	if ((fp=fopen(file, "r")) == NULL) {
		fprintf(stderr, "File not found: %s\n", file);
		kleenex(0);
	}
	stat(file, &statbuf);
	printf("File '%s' ready for transmission.......", file);
	printf("%d blocks\n", statbuf.st_size / 128 + 1);
	printf("Type ^X to exit, xtrans ignores signals\n");
	fflush(stdin);
	new.c_iflag = 0;
	new.c_oflag = 0;
	new.c_lflag &= ~(ICANON|ECHO);
	new.c_cc[4] = 1;
	new.c_cflag &= ~PARENB;
	new.c_cflag |= CS8;
	ioctl(1, TCSETAW, &new);
	get_x_char(60, &buf[0]);
	if (buf[0] != nak) {
	if (debug) 	fprintf(errors, "Didn't get a startup NAK\n");
		kleenex(0);
	}
	numread = read_in(fp, buf, 128);
	while (numread > 0) {
		if (numread < 128) {
			for (i=numread; i< 128; i++) buf[i] = 0;
		}
		write(1, &soh, 1);
		write(1, &blocknum, 1);
		write(1, &c_blocknum, 1);
		write(1, buf, 128);
		cksum = 0;
		for (i=0;i<128;i++) cksum += buf[i];
		cksum = cksum % 256;
		write(1, &cksum, 1);
		j = get_x_char(15, &inch);
		if (j >= 0 && inch == nak) {
			if (debug) fprintf(errors, "Got a nak after block %d\n",blocknum);
			clear_iq();
			continue;
		}
		if (j >= 0 && inch == can) {
			if (debug) fprintf(errors, "Got a cancel after block %d\n",blocknum);
			kleenex(0);
		}
		if (j >= 0 && inch != ack) {
			if (debug) fprintf(errors, "Got a non-ack after block %d, char was %o\n",blocknum,inch);
			clear_iq();
			continue;
		}
		if (j == -1) {
			if (debug) fprintf(errors, "Got a timeout after block %d\n",blocknum);
			continue;
		}
		numread = read_in(fp, buf, 128);
		blocknum = (blocknum + 1) % 256;
		c_blocknum = 255 - blocknum;
	}
	while (1) {
		write(1, &eot, 1);
		j = get_x_char(15, &inch);
		if (j >= 0 && inch == nak) {
			if (debug) fprintf(errors, "Got a nak after block %d\n",blocknum);
			clear_iq();
			continue;
		}
		if (j >= 0 && inch == can) {
			if (debug) fprintf(errors, "Got a cancel during EOT\n");
			kleenex(0);
		}
		if (j >= 0 && inch != ack) {
			if (debug) fprintf(errors, "Got a non-ack during EOT, char was %o\n",inch);
			clear_iq();
			continue;
		}
		if (j == -1) {
			if (debug) fprintf(errors, "Got a timeout during EOT\n");
			continue;
		}
		break;
	}
	kleenex(0);
}
kleenex(x)
int x;
{
	ioctl(1, TCSETA, &save);
	if (debug) fprintf(errors, "Caught signal %d\n", x);
	exit();
}
alarmfn() {
	signal(14, alarmfn);
}
read_in(fp, buf, num)
FILE *fp;
char *buf;
int num;
{
	int i;
	int c;
	static int cr_held = 0;
	static eof_fts = 0;

	i = 0;
	if (cr_held) {
		buf[i] = '\n';
		i++;
		cr_held = 0;
	}
	for(   ;i < num;i++) {
		if (eof_fts == 1) return(i);
		c = getc(fp);
		if (c == EOF) {
			eof_fts = 1;
			c = 26;	/* MS-DOS eot Character */
		}
		if (c == '\n' && lfproc) {
			buf[i] = '\r';
			if (i == 127) {
				cr_held = 1;
				return(128);
			}
			buf[i+1] = '\n';
			i++;
		}
		else {
			buf[i] = c;
		}
	}
	return(i);
}
clear_iq() {
	int j;
	char ch;

	signal(14, alarmfn);
	do {
		alarm(2);
		j = read(0, &ch, 1);
		alarm(0);
		if (debug) fprintf(errors, "cleared line of %o\n", ch);
	} while (j > -1);
}
get_x_char(timeout, cp)
int timeout;
char *cp;
{
	int ch;
	extern int errno;
	int ret;

	alarm(timeout);
	if ((ch=getchar()) == EOF) {
		/*if (debug) fprintf(errors, "get_x_char returning read error\n");*/
		/*if (debug) fprintf(errors, "Errno == %d\n", errno);*/
		return(-1);
	}
	alarm(0);
	*cp = ch;
	return( ch );
}
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