Another version increment.

[xtoys] / xwait.c

/* -*-c-*-
 *
 * $Id: xwait.c,v 1.5 1998/11/30 22:36:53 mdw Exp $
 *
 * Wait until prodded by another X client
 *
 * (c) 1998 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the Edgeware X tools collection.
 *
 * X tools 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 2 of the License, or
 * (at your option) any later version.
 * 
 * X tools 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 X tools; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: xwait.c,v $
 * Revision 1.5  1998/11/30 22:36:53  mdw
 * Tidy up tabbing in help texts very slightly.
 *
 * Revision 1.4  1998/11/21 22:41:19  mdw
 * Reap children which die before I get my signal handler installed.
 *
 * Revision 1.3  1998/11/21 22:30:27  mdw
 * Support GNU-style long options throughout, and introduce proper help
 * text to all programs.  Update manual pages to match.
 *
 * Revision 1.2  1998/11/18 21:25:06  mdw
 * Reap dead children as they arrive.  The previous shell may have
 * carelessly left them behind.
 *
 * Revision 1.1  1998/11/16 23:00:49  mdw
 * Initial versions.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>

#include "mdwopt.h"
#include "quis.h"
#include "xwait.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @sigchld@ --- */

static void sigchld(int sig)
{
  while (waitpid(-1, 0, WNOHANG) > 0)
    ;
}

/* --- @main@ --- */

static void version(FILE *fp)
{
  fprintf(fp, "%s (xtoys version " VERSION ")\n", QUIS);
}

static void usage(FILE *fp)
{
  fprintf(fp, "Usage: %s [-f] [-d DISPLAY] [-a ATOM] [-m MSG]\n", QUIS);
}

int main(int argc, char *argv[])
{
  char *display = 0;
  Display *dpy;
  Atom xwait_die;
  XEvent ev;
  char *atom = XWAIT_DIE;
  char *msg = XWAIT_DIE_MSG;
  unsigned f = 0;

  enum {
    f_force = 1
  };

  /* --- Parse options --- */

  ego(argv[0]);

  for (;;) {
    static struct option opt[] = {
      { "help", 	0,			0,	'h' },
      { "usage", 	0,			0,	'u' },
      { "version", 	0,			0,	'v' },
      { "display", 	required_argument,	0,	'd' },
      { "atom",		required_argument,	0,	'a' },
      { "msg",		required_argument,	0,	'm' },
      { "force",	0,			0,	'f' },
      {	0,		0,			0,	0 }
    };

    int i = getopt_long(argc, argv, "d:a:m:f", opt, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'h':
	version(stdout);
	fputs("\n", stdout);
	usage(stdout);
	fputs(
"\n"
"Waits until signalled by `xtell' or `xshutdown'.  Specifically, waits\n"
"until a property with name ATOM is written to the root window with\n"
"contents MSG.\n"
"\n"
"Options:\n"
"\n"
"-h, --help		Display this help text\n"
"-u, --usage		Display a short usage summary\n"
"-v, --version		Display the program's version number\n"
"\n"
"-d, --display=DISPLAY	Choose X display to connect to\n"
"-f, --force		Run even if this property is waited for by another\n"
"			process\n"
"-a, --atom=ATOM\t	Choose property name to listen for\n"
"-m, --msg=MSG		Choose value of property to wait for\n",
          stdout);
	exit(0);
	break;
      case 'u':
	usage(stdout);
	exit(0);
	break;
      case 'v':
	version(stdout);
	exit(0);
	break;
	
      case 'd':
	display = optarg;
	break;
      case 'a':
	atom = optarg;
	break;
      case 'm':
	msg = optarg;
	break;
      case 'f':
	f |= f_force;
	break;
      default:
	usage(stderr);
	exit(EXIT_FAILURE);
	break;
    }
  }

  /* --- Connect to the X display --- */

  dpy = XOpenDisplay(display);
  if (!dpy) {
    fprintf(stderr, "xwait: couldn't open display\n");
    exit(EXIT_FAILURE);
  }

  /* --- Fetch the property name atom --- */

  xwait_die = XInternAtom(dpy, atom, False);

  /* --- Mark ourselves as listening to all the screens --- */

  {
    int i;
    int nsc = ScreenCount(dpy);

    /* --- First pass: make sure there's not a process already here --- */

    if ((f & f_force) == 0) {
      for (i = 0; i < nsc; i++) {
	Window win = RootWindow(dpy, i);
	XTextProperty prop;

	if (XGetTextProperty(dpy, win, &prop, xwait_die)) {
	  fprintf(stderr, "xwait: already waiting for `%s'\n", atom);
	  exit(EXIT_FAILURE);
	}
      }
    }

    /* --- Second pass: set up listening to the property --- */

    for (i = 0; i < nsc; i++) {
      Window win = RootWindow(dpy, i);
      XTextProperty prop;
      char *imsg = "XWAIT_READY";

      XStringListToTextProperty(&imsg, 1, &prop);
      XSetTextProperty(dpy, win, &prop, xwait_die);
      XSelectInput(dpy, win, PropertyChangeMask);
    }
  }

  /* --- Set up a handler when children die --- *
   *
   * I don't fork any children?  Why is this useful?  Because I've been
   * execed from a shell which started lots of background processes, and
   * they'll zombie themselves otherwise.
   */

  {
    struct sigaction sa;
    sigset_t ss, oss;

    /* --- Set the handler up --- */

    sa.sa_handler = sigchld;
    sigemptyset(&sa.sa_mask);
    sigaddset(&sa.sa_mask, SIGCHLD);
    sa.sa_flags = 0;
    sigaction(SIGCHLD, &sa, 0);

    /* --- Now reap any which have been waiting around so far --- */

    sigemptyset(&ss);
    sigaddset(&ss, SIGCHLD);
    sigprocmask(SIG_BLOCK, &ss, &oss);
    sigchld(SIGCHLD);
    sigprocmask(SIG_SETMASK, &oss, 0);
  }

  /* --- Now wait for an event --- */

  for (;;) {
    XNextEvent(dpy, &ev);
    switch (ev.type) {
      case PropertyNotify:
	if (ev.xproperty.atom == xwait_die) {
	  XTextProperty prop;
	  char **sl;
	  int c;

	  if (XGetTextProperty(dpy, ev.xproperty.window, &prop, xwait_die)) {
	    XTextPropertyToStringList(&prop, &sl, &c);
	    if (strcmp(sl[0], msg) == 0)
	      goto exit;
	    XFreeStringList(sl);
	  }
	}
    }
  }

  /* --- Finished: remove the property from all the screens --- */

exit:
  {
    int i;
    int nsc = ScreenCount(dpy);

    for (i = 0; i < nsc; i++)
      XDeleteProperty(dpy, RootWindow(dpy, i), xwait_die);
  }

  /* --- Go away --- */

  XCloseDisplay(dpy);
  return (0);
}

/*----- That's all, folks -------------------------------------------------*/