/***  tout - a personal timeout program****  Andrew Rudoff, University of Colorado, Boulder****  usage: tout minutes****  This is a voluntary timeout program.  A timeout occurs when the user**  is idle for a time larger than "minutes."  The inaccuracy can be as**  much as 1 minute (1 minute granularity).  The user is warned 1 minute**  before the timeout; the timeout can be prevented by typing any key to**  clear the idle status of the terminal.*/#include <stdio.h>#include <signal.h>#include <sys/types.h>#include <sgtty.h>#include <sys/stat.h>#define BEEP '\007'main(argc, argv)int             argc;char            **argv;{char            user[50];           /* name of current user */char            invoker[50];        /* name of invoker */struct          stat statbuf;       /* buffer for stats on tty */long            current, timeout;   /* times in seconds */int             pgrp, tmp = 0;    if (argc != 2)    {        fprintf(stderr, "usage: %s minutes\n", argv[0]);        exit(1);    }    nice(4);    /* run gracefully in the background */    if ((timeout = 60 * atoi(argv[1])) == 0)    {        fprintf(stderr, "%s: incomprehensible or zero timeout\n", argv[0]);        exit(1);    }    if (!isatty(0))    {        fprintf(stderr, "%s: stdin not a terminal\n", argv[0]);        exit(1);    }            strcpy(invoker, getlogin());    printf("Timeout set for %s (%s minutes)\n", invoker, argv[1]);    fflush(stdout);    if (fork())    {        exit(0);    }    while(1)    {        sleep(60);  /* spend most of my spare time sleeping */        strcpy(user, getlogin());                /* Be sure same person is logged in */                if (strcmp(user, invoker))        {            exit(0);        }        if ((fstat(0, &statbuf)) != 0)        {            fprintf(stderr, "%s: couldn't stat tty\n", argv[0]);            exit(1);        }        time(&current);        if (current - statbuf.st_atime >= timeout)        {            fprintf(stderr, "\n\n%s: Timeout - you're outta here!\n\n",                argv[0]);            while(ioctl(0, TIOCGPGRP, &pgrp), pgrp != tmp)            {                tmp = pgrp;                killpg(pgrp, SIGHUP);   /* Let editors save, etc */                sleep(5);            }                        vhangup();            exit(0);        }        if (current + 60 - statbuf.st_atime >= timeout)        {            fprintf(stderr, "\n%s: WARNING - timeout in 1 minute.%c\n",                argv[0], BEEP);        }    }}