(no message)

[unix-history] / usr / src / usr.bin / wall / wall.c

/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980 Regents of the University of California.\n\
All rights reserved.\n";
#endif not lint

#ifndef lint
static char sccsid[] = "@(#)wall.c      5.1 (Berkeley) %G%";
#endif not lint

/*
* wall.c - Broadcast a message to all users.
*
* This program is not related to David Wall, whose Stanford Ph.D. thesis
* is entitled "Mechanisms for Broadcast and Selective Broadcast".
*/

#include <stdio.h>
#include <utmp.h>
#include <errno.h>
#include <signal.h>
#include <sys/time.h>
#include <fcntl.h>

#define USERS   128
#define IGNOREUSER      "sleeper"

char    hostname[32];
char    mesg[3000];
int     msize,sline;
struct  utmp utmp[USERS];
char    *strcpy();
char    *strcat();
char    who[9] = "???";
long    clock, time();
struct tm *localtime();
struct tm *localclock;

extern  errno;

main(argc, argv)
char *argv[];
{
       register int i, c;
       register struct utmp *p;
       FILE *f;

       gethostname(hostname, sizeof (hostname));
       if ((f = fopen("/etc/utmp", "r")) == NULL) {
               fprintf(stderr, "Cannot open /etc/utmp\n");
               exit(1);
       }
       clock = time( 0 );
       localclock = localtime( &clock );
       sline = ttyslot();      /* 'utmp' slot no. of sender */
       c = fread((char *)utmp, sizeof(struct utmp), USERS, f);
       fclose(f);
       if (sline)
               strncpy(who, utmp[sline].ut_name, sizeof(utmp[sline].ut_name));
       sprintf(mesg,
           "\n\a\a\aBroadcast Message from %s@%s (%.*s) at %d:%02d ...\r\n\n"
               , who
               , hostname
               , sizeof(utmp[sline].ut_line)
               , utmp[sline].ut_line
               , localclock -> tm_hour
               , localclock -> tm_min
       );
       msize = strlen(mesg);
       if (argc >= 2) {
               /* take message from unix file instead of standard input */
               if (freopen(argv[1], "r", stdin) == NULL) {
                       perror(argv[1]);
                       exit(1);
               }
       }
       while ((i = getchar()) != EOF) {
               if (i == '\n')
                       mesg[msize++] = '\r';
               if (msize >= sizeof mesg) {
                       fprintf(stderr, "Message too long\n");
                       exit(1);
               }
               mesg[msize++] = i;
       }
       fclose(stdin);
       for (i=0; i<c; i++) {
               p = &utmp[i];
               if (p->ut_name[0] == 0 ||
                   strncmp(p->ut_name, IGNOREUSER, sizeof(p->ut_name)) == 0)
                       continue;
               sendmes(p->ut_line);
       }
       exit(0);
}

sendmes(tty)
char *tty;
{
       register f, flags;
       static char t[50] = "/dev/";
       int e, i;

       strcpy(t + 5, tty);

       if ((f = open(t, O_WRONLY|O_NDELAY)) < 0) {
               if (errno != EWOULDBLOCK)
                       perror(t);
               return;
       }
       if ((flags = fcntl(f, F_GETFL, 0)) == -1) {
               perror(t);
               return;
       }
       if (fcntl(f, F_SETFL, flags | FNDELAY) == -1)
               goto oldway;
       i = write(f, mesg, msize);
       e = errno;
       (void) fcntl(f, F_SETFL, flags);
       if (i == msize) {
               (void) close(f);
               return;
       }
       if (e != EWOULDBLOCK) {
               errno = e;
               perror(t);
               (void) close(f);
               return;
       }
oldway:
       while ((i = fork()) == -1)
               if (wait((int *)0) == -1) {
                       fprintf(stderr, "Try again\n");
                       return;
               }
       if (i) {
               (void) close(f);
               return;
       }

       (void) write(f, mesg, msize);
       exit(0);
}