mdw@git.distorted.org.uk Git - xtoys/blob - xwait.c

   1 /* -*-c-*-
   2  *
   3  * $Id: xwait.c,v 1.3 1998/11/21 22:30:27 mdw Exp $
   4  *
   5  * Wait until prodded by another X client
   6  *
   7  * (c) 1998 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the Edgeware X tools collection.
  13  *
  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.
  18  *
  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.
  23  *
  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.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: xwait.c,v $
  32  * Revision 1.3  1998/11/21 22:30:27  mdw
  33  * Support GNU-style long options throughout, and introduce proper help
  34  * text to all programs.  Update manual pages to match.
  35  *
  36  * Revision 1.2  1998/11/18 21:25:06  mdw
  37  * Reap dead children as they arrive.  The previous shell may have
  38  * carelessly left them behind.
  39  *
  40  * Revision 1.1  1998/11/16 23:00:49  mdw
  41  * Initial versions.
  42  *
  43  */
  44
  45 /*----- Header files ------------------------------------------------------*/
  46
  47 #include <signal.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51
  52 #include <sys/types.h>
  53 #include <sys/wait.h>
  54 #include <unistd.h>
  55
  56 #include <X11/Xlib.h>
  57 #include <X11/Xutil.h>
  58
  59 #include "mdwopt.h"
  60 #include "quis.h"
  61 #include "xwait.h"
  62
  63 /*----- Main code ---------------------------------------------------------*/
  64
  65 /* --- @sigchld@ --- */
  66
  67 static void sigchld(int sig)
  68 {
  69   while (waitpid(-1, 0, WNOHANG) > 0)
  70     ;
  71 }
  72
  73 /* --- @main@ --- */
  74
  75 static void version(FILE *fp)
  76 {
  77   fprintf(fp, "%s (xtoys version " VERSION ")\n", QUIS);
  78 }
  79
  80 static void usage(FILE *fp)
  81 {
  82   fprintf(fp, "Usage: %s [-f] [-d DISPLAY] [-a ATOM] [-m MSG]\n", QUIS);
  83 }
  84
  85 int main(int argc, char *argv[])
  86 {
  87   char *display = 0;
  88   Display *dpy;
  89   Atom xwait_die;
  90   XEvent ev;
  91   char *atom = XWAIT_DIE;
  92   char *msg = XWAIT_DIE_MSG;
  93   unsigned f = 0;
  94
  95   enum {
  96     f_force = 1
  97   };
  98
  99   /* --- Parse options --- */
 100
 101   ego(argv[0]);
 102
 103   for (;;) {
 104     static struct option opt[] = {
 105       { "help",         0,                      0,      'h' },
 106       { "usage",        0,                      0,      'u' },
 107       { "version",      0,                      0,      'v' },
 108       { "display",      required_argument,      0,      'd' },
 109       { "atom",         required_argument,      0,      'a' },
 110       { "msg",          required_argument,      0,      'm' },
 111       { "force",        0,                      0,      'f' },
 112       { 0,              0,                      0,      0 }
 113     };
 114
 115     int i = getopt_long(argc, argv, "d:a:m:f", opt, 0);
 116     if (i < 0)
 117       break;
 118     switch (i) {
 119       case 'h':
 120         version(stdout);
 121         fputs("\n", stdout);
 122         usage(stdout);
 123         fputs(
 124 "\n"
 125 "Waits until signalled by `xtell' or `xshutdown'.  Specifically, waits\n"
 126 "until a property with name ATOM is written to the root window with\n"
 127 "contents MSG.\n"
 128 "\n"
 129 "Options:\n"
 130 "\n"
 131 "-h, --help             Display this help text\n"
 132 "-u, --usage            Display a short usage summary\n"
 133 "-v, --version          Display the program's version number\n"
 134 "\n"
 135 "-d, --display=DISPLAY  Choose X display to connect to\n"
 136 "-f, --force            Run even if this property is waited for by another\n"
 137 "                       process\n"
 138 "-a, --atom=ATOM                Choose property name to listen for\n"
 139 "-m, --msg=MSG          Choose value of property to wait for\n",
 140           stdout);
 141         exit(0);
 142         break;
 143       case 'u':
 144         usage(stdout);
 145         exit(0);
 146         break;
 147       case 'v':
 148         version(stdout);
 149         exit(0);
 150         break;
 151
 152       case 'd':
 153         display = optarg;
 154         break;
 155       case 'a':
 156         atom = optarg;
 157         break;
 158       case 'm':
 159         msg = optarg;
 160         break;
 161       case 'f':
 162         f |= f_force;
 163         break;
 164       default:
 165         usage(stderr);
 166         exit(EXIT_FAILURE);
 167         break;
 168     }
 169   }
 170
 171   /* --- Connect to the X display --- */
 172
 173   dpy = XOpenDisplay(display);
 174   if (!dpy) {
 175     fprintf(stderr, "xwait: couldn't open display\n");
 176     exit(EXIT_FAILURE);
 177   }
 178
 179   /* --- Fetch the property name atom --- */
 180
 181   xwait_die = XInternAtom(dpy, atom, False);
 182
 183   /* --- Mark ourselves as listening to all the screens --- */
 184
 185   {
 186     int i;
 187     int nsc = ScreenCount(dpy);
 188
 189     /* --- First pass: make sure there's not a process already here --- */
 190
 191     if ((f & f_force) == 0) {
 192       for (i = 0; i < nsc; i++) {
 193         Window win = RootWindow(dpy, i);
 194         XTextProperty prop;
 195
 196         if (XGetTextProperty(dpy, win, &prop, xwait_die)) {
 197           fprintf(stderr, "xwait: already waiting for `%s'\n", atom);
 198           exit(EXIT_FAILURE);
 199         }
 200       }
 201     }
 202
 203     /* --- Second pass: set up listening to the property --- */
 204
 205     for (i = 0; i < nsc; i++) {
 206       Window win = RootWindow(dpy, i);
 207       XTextProperty prop;
 208       char *imsg = "XWAIT_READY";
 209
 210       XStringListToTextProperty(&imsg, 1, &prop);
 211       XSetTextProperty(dpy, win, &prop, xwait_die);
 212       XSelectInput(dpy, win, PropertyChangeMask);
 213     }
 214   }
 215
 216   /* --- Set up a handler when children die --- *
 217    *
 218    * I don't fork any children?  Why is this useful?  Because I've been
 219    * execed from a shell which started lots of background processes, and
 220    * they'll zombie themselves otherwise.
 221    */
 222
 223   {
 224     struct sigaction sa;
 225
 226     sa.sa_handler = sigchld;
 227     sigemptyset(&sa.sa_mask);
 228     sigaddset(&sa.sa_mask, SIGCHLD);
 229     sa.sa_flags = 0;
 230     sigaction(SIGCHLD, &sa, 0);
 231   }
 232
 233   /* --- Now wait for an event --- */
 234
 235   for (;;) {
 236     XNextEvent(dpy, &ev);
 237     switch (ev.type) {
 238       case PropertyNotify:
 239         if (ev.xproperty.atom == xwait_die) {
 240           XTextProperty prop;
 241           char **sl;
 242           int c;
 243
 244           if (XGetTextProperty(dpy, ev.xproperty.window, &prop, xwait_die)) {
 245             XTextPropertyToStringList(&prop, &sl, &c);
 246             if (strcmp(sl[0], msg) == 0)
 247               goto exit;
 248             XFreeStringList(sl);
 249           }
 250         }
 251     }
 252   }
 253
 254   /* --- Finished: remove the property from all the screens --- */
 255
 256 exit:
 257   {
 258     int i;
 259     int nsc = ScreenCount(dpy);
 260
 261     for (i = 0; i < nsc; i++)
 262       XDeleteProperty(dpy, RootWindow(dpy, i), xwait_die);
 263   }
 264
 265   /* --- Go away --- */
 266
 267   XCloseDisplay(dpy);
 268   return (0);
 269 }
 270
 271 /*----- That's all, folks -------------------------------------------------*/