karl@ddsw1.UUCP (Karl Denninger) (05/11/88)
Here's a small utility which has been floating around to send single-line
messages to another user's terminal. This version searches for the first
writable terminal if there is more than one.
It's small and handy -- ideal qualities.
Should compile and run on either Microport or SCO Xenix (was last tested on
SCO Xenix V/386 2.2.1).
/*
* send.c - send a one-line message to another user
* Bill Wisner, billw@killer.UUCP
* Modified to send to the first writable terminal by karl@ddsw1
*/
#ifndef lint
static char *SccsId = "@(#)send.c 1.1 05/10/88";
#endif /* lint */
#include <stdio.h>
#include <sys/types.h>
#include <utmp.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
main(argc,argv)
int argc;
char *argv[];
{
char *to, *message, *tty = "/dev/null", *devname, *malloc();
int device, logins = 0;
register int i;
struct utmp *utent, *getutent();
if (argc < 3) {
(void)printf("Usage: %s user message\n",argv[0]);
exit(1);
}
to = malloc(9);
sprintf(to,"%s",argv[1]);
do { /* See how many times victim is logged in, if any */
utent = getutent();
if (strcmp(utent->ut_user,to) == 0)
logins++;
} while (utent != NULL);
if (logins == 0) {
(void)printf("%s: %s is not logged in.\n",argv[0],to);
exit(1);
}
/*
* Now look at all logins, and send to the first write-enabled terminal
* we find. Ignore the rest. Complain only if there is no place to put
* the user's message. This is better than just blindly trying the first
* port in the hopes it is writable. - KSD 5/10/88
*
*/
setutent(); /* Rewind utmp file */
devname = malloc(20);
message = malloc(512); /* Please gimme memory :-) */
sprintf(message,"\007\n;;%s:",getlogin());
for(i=2;i<argc;i++) {
(void)sprintf(message,"%s %s",message,argv[i]);
}
sprintf(message,"%s\n",message);/* Message is built, find a line */
do {
utent = getutent();
if (strcmp(utent->ut_user, to) == 0) { /* Check this line */
sprintf(devname, "/dev/%s", utent->ut_line);
device = open(devname,O_WRONLY);
if (device == -1) {
if (errno != EACCES) {
printf("%s: Cannot open %s!\n", argv[0], devname);
continue;
}
} else {
if (write(device,message,strlen(message)) == -1) {
close(device);
continue;
} else
if (logins > 1)
printf("To %s (%d logins).\n", utent->ut_line, logins);
exit(0); /* Get out, delivered */
}
}
} while (utent != NULL);
printf("%s: Cannot write to user %s\n", argv[0], to);
exit(1);
}
----
Karl Denninger | Data: +1 312 566-8912
Macro Computer Solutions, Inc. | Voice: +1 312 566-8910
...ihnp4!ddsw1!karl | "Quality solutions for work or play"