Hackers Toolkit 2.0/Hackers_Toolkit_v2.0.iso/HTML/archive/Unix/c-src/force.c

C/C++ Source or Header | 1999-11-04 | 5.4 KB | 213 lines

/*
 * force.c - v1.3 - by Brendan Kehoe ([e-mail])
 *
 *  v1.0 - 10/15/90 - force execution of a command on the user's command line
 *  v1.1 - 11/19/90 - allow a pseudo-interactive session, of sorts
 *  v1.2 - 11/20/90 - made the thing error check itself into oblivion
 *  v1.3 -  7/16/91 - Ported to SGI by Dan Watts
 *
 * Usage: force [ -n ] [ -l /dev/ttyxx ]
 *       -n              - use this if you don't want the command to echo
 *       -l /dev/ttyxx   - the line to hit; use the full name (e.g. /dev/ttyp0)
 *
 *  Compiles under SGI Irix, SunOS 4.1, Ultrix 3.1D, and Ultrix 4.1. No
 *   promises are made for other OS's or systems.
 *
 *  It won't work under System V Release anything until an alternative
 *  to the TIOCSTI ioctl comes around. (Or you use SVR4, I'm told.)
 *
 * (Yes, this requires you be root to use it.)
 *
 * To use it, just type whatever at the Force> prompt, and when you
 * hit return, that line will get sent onto the user's input queue,
 * so it's like they typed it.  Use Control-V to quote control characters
 * like Control-C.  Type -X- on an empty line to quit out.
 *
 * You're welcome to do whatever you want with this, as long as you note
 * its origin somewhere. (Namely "This Was Written By Brendan Kehoe", for
 * starters.) (A 19-page writeup would be cool, too, but maybe it's too much.)
 */

#include <stdio.h>
#include <sys/types.h>        /* for stat(2) */
#include <sys/stat.h>        /* for stat(2) */
#include <fcntl.h>
#ifdef sgi
# include <sys/termio.h>
# define termios    termio
# define TCGETS        TCGETA
# define TCSETS        TCSETA
#else
#include <sys/termios.h>
#endif

#ifdef ultrix
# include <sys/ioctl.h>
# define    TCGETS    TCGETP
# define    TCSETS    TCSANOW
#endif /* ultrix */

void push(), devchk();

extern char    *optarg;
extern int    optind;
short no_echo = 0;

#define    USAGE        "usage: %s [-n] [-l /dev/ttyxx]\n",*argv
#define COMMAND_LIM 100

int
main(argc, argv)
     int argc;
     char **argv;
{
  int f, cnt;
  short true = 1, no_cmd = 0;
  char *device, *buf, *trail, chr;

  if (argc > 4) {
    fprintf(stderr, USAGE);
    exit(1);
  }

  if ((device = (char *)malloc(40)) == (char *)NULL) {
    perror("malloc 1");
    exit(1);
  }

  if ((buf = (char *) malloc(COMMAND_LIM)) == (char *)NULL) {
    perror("malloc 1a");
    exit(1);
  }

  while ((chr = getopt(argc, argv, "nl:")) != -1)
    switch (chr) {
    case 'n':
      no_echo = 1;
      break;
    case 'l':
      (void) devchk(optarg, *argv);
      device = optarg;
      break;
    default:
      fprintf(stderr, USAGE);
      exit(1);
    }

  if (strlen(device) < 2) {
    printf("Device [form: /dev/ttyxx]: ");
    fflush(stdout);
    fgets(device, 39, stdin);
    /* cut off the trailing return that fgets leaves on */
    if ((*device) && (*(trail=(char *)(device + strlen(device) - 1)) == '\n'))
      *trail = '\0';
    if (strlen(device) > 7)
      (void) devchk(device, *argv);
    else {
      fprintf(stderr, "%s: give full name [e.g. /dev/ttyp0].\n", *argv);
      exit(1);
    }
  }

  printf("Terminate with '-X-' on a line by itself.\n");
  while (true) {
    no_cmd = cnt = 0;
    chr = *buf = '\0';
    printf("Force> ");
    rewind(stdin);
    while (((chr=getchar()) != '\n') && (chr != EOF) && (cnt < COMMAND_LIM))
      *(buf + cnt++) = chr;
    if (cnt == COMMAND_LIM) {
      printf("Limit of %d characters per command line.\n", COMMAND_LIM);
      no_cmd = 1;
    }
    if (chr == EOF) {
      putc('\n', stdout);
      exit(0);
    }
    if (!no_cmd) {
      *(buf + cnt) = '\0';
      if (!strcmp(buf, "-X-"))
    true = 0;
      else if ((*buf != '\n') && (*buf != '\0')) {
    if ((f = open(device, O_NDELAY | O_RDWR)) < 0) {
      perror("open");
      exit(1);
    }
    push(f, buf);
    close(f);
      }
    }
  }
}

void
push(f, s)
     int f;
     char *s;
{
  register int i;
  char ret='\n';
  struct termios termios;

  if (no_echo) {
    if (ioctl(f, TCGETS, &termios) < 0) {
      perror("ioctl 1");
      exit(1);
    }
    termios.c_lflag &= ~ECHO;
    if (ioctl(f, TCSETS, &termios) < 0) {
      perror("ioctl 2");
      exit(1);
    }
  }

  if (ioctl(f, TCFLSH, 0)  < 0) {        /* flush the input queue */
    perror("ioctl 3");
    exit(1);
  }

  for (i = 0; i < strlen(s); i++)              /* give 'em the command */
    ioctl(f, TIOCSTI, s + i);
  ioctl(f, TIOCSTI, &ret);                     /* including a return */

  if (no_echo) {
    ioctl(f, TCGETS, &termios);
    termios.c_lflag |= ECHO;
    ioctl(f, TCSETS, &termios);

    ioctl(f, TCFLSH, 1);                       /* flush the output queue */
  }
}

void
devchk(device, prg)
     char *device, *prg;
{
  struct stat sb;

  if (strncmp(device, "/dev/tt", 7) && strncmp(device, "/dev/co", 7)) {
    fprintf(stderr, "%s: give full name [e.g. /dev/ttyp0].\n", prg);
    exit(1);
  }
  if (!strcmp(device, ttyname(0))) {
    fprintf(stderr, "%s: you can't force yourself, you masochist.\n",
        prg);
    exit(1);
  }
  if (strlen(device) > 40) {
    fprintf(stderr, "%s: terminal name too long.\n", prg);
    exit(1);
  }

  /*
   * there's probably a cleaner way to do this (not having the struct down
   * here at all); I considered using alloca, then decided not to. I'm open
   * to suggestions. - BK 11/20
   */
  if (stat(device, (struct stat *)&sb) < 0) {
    perror(prg);
    exit(1);
  }
}