usr/src/usr.bin/uucp/uucico/imsg.c

#ifndef lint
static char sccsid[] = "@(#)imsg.c      5.2 (Berkeley) %G%";
#endif

#include "uucp.h"

char Msync[2] = "\020";

/* to talk to both eunice and x.25 without also screwing up tcp/ip
 * we must adaptively  choose what character to end the msg with
 *
 * The idea is that initially we send ....\000\n
 * Then, after they have sent us a message, we use the first character
 * they send.
 */

int seenend = 0;
char Mend = '\0';

/*
 *      this is the initial read message routine -
 *      used before a protocol is agreed upon.
 *
 *      return codes:
 *              EOF - no more messages
 *              0 - message returned
 */

imsg(msg, fn)
register char *msg;
register int fn;
{
        register int ret;
        char *amsg;

        DEBUG(5, "imsg %s<", "sync");
        while ((ret = read(fn, msg, 1)) == 1) {
                *msg &= 0177;
                DEBUG(5, (*msg>037 && *msg<0177) ? "%c" : "\\%03o", *msg & 0377);
                if (*msg == Msync[0])
                        break;
                fflush(stderr);
        }
        DEBUG(5, ">got %s\n", ret == 1 ? "it" : "EOF");
        if (ret < 1)
                return EOF;
        amsg = msg;
resync:
        DEBUG(5, "imsg %s<", "input");
        while (read(fn, msg, 1) == 1) {
                *msg &= 0177;
                DEBUG(5, (*msg>037 && *msg<0177) ? "%c" : "\\%03o", *msg & 0377);
                if (*msg == Msync[0]) {
                        DEBUG(5, "%s\n", ">found sync");
                        msg = amsg;
                        goto resync;
                }
                if (*msg == '\n' || *msg == '\0') {
                        if (!seenend) {
                                Mend = *msg;
                                seenend++;
                                DEBUG(6,"\nUsing \\%o as End of message char\n", Mend);
                        }
                        break;
                }
                msg++;
                fflush(stderr);
        }
        *msg = '\0';
        DEBUG(5, ">got %d\n", strlen(amsg));
        return 0;
}


/*
 *      this is the initial write message routine -
 *      used before a protocol is agreed upon.
 *
 *      return code:  always 0
 */

omsg(type, msg, fn)
register char *msg;
char type;
int fn;
{
        char buf[MAXFULLNAME];
        register char *c;

        c = buf;
        *c = '\0';      /* avoid pdp 11/23,40 auto-incr stack trap bug */
        *c++ = Msync[0];
        *c++ = type;
        while (*msg)
                *c++ = *msg++;
        *c++ = '\0';
        DEBUG(5, "omsg <%s>\n", buf);
        if (seenend)
                c[-1] = Mend;
        else
                *c++ = '\n';
        write(fn, buf, (int)(c - buf));
        return 0;
}