date and time created 84/04/11 15:02:40 by karels

[unix-history] / usr / src / libexec / talkd / announce.c

/* $Header: /a/guest/moore/talk/RCS/announce.c,v 1.8 83/07/06 00:16:57 moore Exp $ */

#include "ctl.h"

#include <sys/stat.h>
#include <sgtty.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <stdio.h>
#include <sys/wait.h>
#include <errno.h>

char *sprintf();

extern int errno;
extern char hostname[];
int nofork = 0;		/* to be set from the debugger */

/*
 * Because the tty driver insists on attaching a terminal-less
 * process to any terminal that it writes on, we must fork a child
 * to protect ourselves
 */

announce(request, remote_machine)
CTL_MSG *request;
char *remote_machine;
{
    int pid, val, status;

    if (nofork) {
	return(announce_proc(request, remote_machine));
    }

    if ( pid = fork() ) {

	    /* we are the parent, so wait for the child */

	if (pid == -1) {
		/* the fork failed */
	    return(FAILED);
	}

	do {
	    val = wait(&status);
	    if (val == -1) {
		if (errno == EINTR) {
		    continue;
		} else {
			/* shouldn't happen */
		    print_error("wait");
		    return(FAILED);
		}
	    }
	} while (val != pid);

	if (status&0377 > 0) {
		/* we were killed by some signal */
	    return(FAILED);
	}

	    /* Get the second byte, this is the exit/return code */

	return((status>>8)&0377);

    } else {
	    /* we are the child, go and do it */
	_exit(announce_proc(request, remote_machine));
    }
}
	

    /* See if the user is accepting messages. If so, announce that 
       a talk is requested.
     */

announce_proc(request, remote_machine)
CTL_MSG *request;
char *remote_machine;
{
    int pid, status;
    char full_tty[32];
    FILE *tf;
    struct stat stbuf;


    (void) sprintf(full_tty, "/dev/%s", request->r_tty);

    if (access(full_tty, 0) != 0) {
	return(FAILED);
    }

    if ((tf = fopen(full_tty, "w")) == NULL) {
	return(PERMISSION_DENIED);
    }

	/* open gratuitously attaches the talkd to
	   any tty it opens, so disconnect us from the
	   tty before we catch a signal */

    ioctl(fileno(tf), TIOCNOTTY, (struct sgttyb *) 0);

    if (fstat(fileno(tf), &stbuf) < 0) {
	return(PERMISSION_DENIED);
    }

    if ((stbuf.st_mode&02) == 0) {
	return(PERMISSION_DENIED);
    }

    print_mesg(tf, request, remote_machine);
    fclose(tf);
    return(SUCCESS);
}

#define max(a,b) ( (a) > (b) ? (a) : (b) )
#define N_LINES 5
#define N_CHARS 120

    /*
     * build a block of characters containing the message. 
     * It is sent blank filled and in a single block to
     * try to keep the message in one piece if the recipient
     * in in vi at the time
     */

print_mesg(tf, request, remote_machine)
FILE *tf;
CTL_MSG *request;
char *remote_machine;
{
    struct timeval clock;
    struct timezone zone;
    struct tm *localtime();
    struct tm *localclock;
    char line_buf[N_LINES][N_CHARS];
    int sizes[N_LINES];
    char big_buf[N_LINES*N_CHARS];
    char *bptr, *lptr;
    int i, j, max_size;

    i = 0;
    max_size = 0;

    gettimeofday(&clock, &zone);
    localclock = localtime( &clock.tv_sec );

    sprintf(line_buf[i], " ");

    sizes[i] = strlen(line_buf[i]);
    max_size = max(max_size, sizes[i]);
    i++;

    sprintf(line_buf[i], "Message from Talk_Daemon@%s at %d:%02d ...",
	hostname, localclock->tm_hour , localclock->tm_min );

    sizes[i] = strlen(line_buf[i]);
    max_size = max(max_size, sizes[i]);
    i++;

    sprintf(line_buf[i], "talk: connection requested by %s@%s.",
		request->l_name, remote_machine);

    sizes[i] = strlen(line_buf[i]);
    max_size = max(max_size, sizes[i]);
    i++;

    sprintf(line_buf[i], "talk: respond with:  talk %s@%s",
		request->l_name, remote_machine);

    sizes[i] = strlen(line_buf[i]);
    max_size = max(max_size, sizes[i]);
    i++;

    sprintf(line_buf[i], " ");

    sizes[i] = strlen(line_buf[i]);
    max_size = max(max_size, sizes[i]);
    i++;

    bptr = big_buf;
    *(bptr++) = '\a';	/* send something to wake them up */
    *(bptr++) = '\r';	/* add a \r in case of raw mode */
    *(bptr++) = '\n';
    for(i = 0; i < N_LINES; i++) {

	    /* copy the line into the big buffer */

	lptr = line_buf[i];
	while (*lptr != '\0') {
	    *(bptr++) = *(lptr++);
	}

	    /* pad out the rest of the lines with blanks */

	for(j = sizes[i]; j < max_size + 2; j++) {
	    *(bptr++) = ' ';
	}

	*(bptr++) = '\r';	/* add a \r in case of raw mode */
	*(bptr++) = '\n';
    }
    *bptr = '\0';

    fprintf(tf, big_buf);
    fflush(tf);
    ioctl(fileno(tf), TIOCNOTTY, (struct sgttyb *) 0);
}