3 * $Id: xwait.c,v 1.7 1999/06/19 23:42:37 mdw Exp $
5 * Wait until prodded by another X client
7 * (c) 1998 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the Edgeware X tools collection.
14 * X tools is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * X tools is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with X tools; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.7 1999/06/19 23:42:37 mdw
33 * Improve signal handling.
35 * Revision 1.6 1998/12/11 09:50:07 mdw
36 * Minor modifications to work with mLib and mgLib.
38 * Revision 1.5 1998/11/30 22:36:53 mdw
39 * Tidy up tabbing in help texts very slightly.
41 * Revision 1.4 1998/11/21 22:41:19 mdw
42 * Reap children which die before I get my signal handler installed.
44 * Revision 1.3 1998/11/21 22:30:27 mdw
45 * Support GNU-style long options throughout, and introduce proper help
46 * text to all programs. Update manual pages to match.
48 * Revision 1.2 1998/11/18 21:25:06 mdw
49 * Reap dead children as they arrive. The previous shell may have
50 * carelessly left them behind.
52 * Revision 1.1 1998/11/16 23:00:49 mdw
57 /*----- Header files ------------------------------------------------------*/
65 #include <sys/types.h>
70 #include <X11/Xutil.h>
72 #include <mLib/mdwopt.h>
73 #include <mLib/quis.h>
77 /*----- Main code ---------------------------------------------------------*/
79 /* --- @sigchld@ --- */
81 static void sigchld(int sig)
84 while (waitpid(-1, 0, WNOHANG) > 0)
91 static void version(FILE *fp)
93 fprintf(fp, "%s (xtoys version " VERSION ")\n", QUIS);
96 static void usage(FILE *fp)
98 fprintf(fp, "Usage: %s [-f] [-d DISPLAY] [-a ATOM] [-m MSG]\n", QUIS);
101 int main(int argc, char *argv[])
107 char *atom = XWAIT_DIE;
108 char *msg = XWAIT_DIE_MSG;
115 /* --- Parse options --- */
120 static struct option opt[] = {
121 { "help", 0, 0, 'h' },
122 { "usage", 0, 0, 'u' },
123 { "version", 0, 0, 'v' },
124 { "display", required_argument, 0, 'd' },
125 { "atom", required_argument, 0, 'a' },
126 { "msg", required_argument, 0, 'm' },
127 { "force", 0, 0, 'f' },
131 int i = getopt_long(argc, argv, "d:a:m:f", opt, 0);
141 "Waits until signalled by `xtell' or `xshutdown'. Specifically, waits\n"
142 "until a property with name ATOM is written to the root window with\n"
147 "-h, --help Display this help text\n"
148 "-u, --usage Display a short usage summary\n"
149 "-v, --version Display the program's version number\n"
151 "-d, --display=DISPLAY Choose X display to connect to\n"
152 "-f, --force Run even if this property is waited for by another\n"
154 "-a, --atom=ATOM\t Choose property name to listen for\n"
155 "-m, --msg=MSG Choose value of property to wait for\n",
187 /* --- Connect to the X display --- */
189 dpy = XOpenDisplay(display);
191 fprintf(stderr, "xwait: couldn't open display\n");
195 /* --- Fetch the property name atom --- */
197 xwait_die = XInternAtom(dpy, atom, False);
199 /* --- Mark ourselves as listening to all the screens --- */
203 int nsc = ScreenCount(dpy);
205 /* --- First pass: make sure there's not a process already here --- */
207 if ((f & f_force) == 0) {
208 for (i = 0; i < nsc; i++) {
209 Window win = RootWindow(dpy, i);
212 if (XGetTextProperty(dpy, win, &prop, xwait_die)) {
213 fprintf(stderr, "xwait: already waiting for `%s'\n", atom);
219 /* --- Second pass: set up listening to the property --- */
221 for (i = 0; i < nsc; i++) {
222 Window win = RootWindow(dpy, i);
224 char *imsg = "XWAIT_READY";
226 XStringListToTextProperty(&imsg, 1, &prop);
227 XSetTextProperty(dpy, win, &prop, xwait_die);
228 XSelectInput(dpy, win, PropertyChangeMask);
232 /* --- Set up a handler when children die --- *
234 * I don't fork any children? Why is this useful? Because I've been
235 * execed from a shell which started lots of background processes, and
236 * they'll zombie themselves otherwise.
243 /* --- Set the handler up --- */
245 sa.sa_handler = sigchld;
246 sigemptyset(&sa.sa_mask);
247 sigaddset(&sa.sa_mask, SIGCHLD);
248 sa.sa_flags = SA_NOCLDSTOP;
250 sa.sa_flags |= SA_RESTART;
252 sigaction(SIGCHLD, &sa, 0);
254 /* --- Now reap any which have been waiting around so far --- */
257 sigaddset(&ss, SIGCHLD);
258 sigprocmask(SIG_BLOCK, &ss, &oss);
260 sigprocmask(SIG_SETMASK, &oss, 0);
263 /* --- Now wait for an event --- */
266 XNextEvent(dpy, &ev);
269 if (ev.xproperty.atom == xwait_die) {
274 if (XGetTextProperty(dpy, ev.xproperty.window, &prop, xwait_die)) {
275 XTextPropertyToStringList(&prop, &sl, &c);
276 if (strcmp(sl[0], msg) == 0)
284 /* --- Finished: remove the property from all the screens --- */
289 int nsc = ScreenCount(dpy);
291 for (i = 0; i < nsc; i++)
292 XDeleteProperty(dpy, RootWindow(dpy, i), xwait_die);
295 /* --- Go away --- */
301 /*----- That's all, folks -------------------------------------------------*/