xss/xkeygrab.c

/* xkeygrab -- grab keyboard and mouse, writing typed lines to stdout
 * Copyright (C) 2008  Neale Pickett <neale@woozle.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <unistd.h>
#include <ctype.h>
#include <poll.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/keysym.h>

#include "obj.h"

int
main(int argc, char *argv[])
{
  Display *display = NULL;

  if (argc != 1) {
    (void)fprintf(stderr, "Usage: %s\n", argv[0]);
    return 64;                  /* EX_USAGE */
  }

  try {
    Window        root;
    char          obuf[4096];
    int           obuflen = 0;
    struct pollfd fds[2];

    if (! (display = XOpenDisplay(NULL))) raise("cannot open display");
    root = DefaultRootWindow(display);

    fds[0].fd = STDOUT_FILENO;
    fds[0].events = 0;
    fds[1].fd = ConnectionNumber(display);
    fds[1].events = POLLIN;
    while (1) {
      int tograb = 3;
      int ret;

      if (tograb) {
        if ((tograb & 1) && (GrabSuccess == XGrabKeyboard(display, root,
                                                          True,
                                                          GrabModeAsync, GrabModeAsync,
                                                          CurrentTime))) {
          tograb |= 1;
        }
        if ((tograb & 2) && (GrabSuccess == XGrabPointer(display, root,
                                                         False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
                                                         GrabModeAsync, GrabModeAsync,
                                                         None, None, CurrentTime))) {
          tograb |= 2;
        }
      }

      ret = poll(fds, 2, (tograb?100:-1));

      if (fds[0].revents & POLLERR) {
        break;
      }
      if (fds[1].revents & POLLIN) {
        XEvent event;

        (void)XNextEvent(display, &event);
        if (KeyPress == event.type) {
          char   buf[32];
          KeySym ksym;
          int    i;

          if (obuflen == sizeof(obuf)) continue;
          i = XLookupString(&event.xkey, buf, sizeof(buf), &ksym, NULL);
          switch (ksym) {
            case XK_Return:
              if (obuflen) {
                (void)write(STDOUT_FILENO, obuf, obuflen);
                (void)write(STDOUT_FILENO, "\n", 1);
                obuflen = 0;
              }
              break;
            case XK_BackSpace:
              if (obuflen) obuflen -= 1;
              break;
            default:
              if (1 == i) {
                switch (buf[0]) {
                  case '\025':
                    obuflen = 0;
                    break;
                  case ' ' ... '~':
                    obuf[obuflen++] = buf[0];
                  break;
                }
              }
              break;
          }
        }
      }
    }
  } while (0);

  if (display) {
    (void)XUngrabKeyboard(display, CurrentTime);
    (void)XUngrabPointer(display, CurrentTime);
    (void)XCloseDisplay(display);
  }

  except {
    (void)fprintf(stderr, "Error: %s\n", exception);
    return 69;                  /* EX_UNAVAILABLE */
  }

  return 0;
}