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

   1 /* -*-c-*-
   2  *
   3  * $Id: xwait.c,v 1.6 1998/12/11 09:50:07 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 1.6  1998/12/11 09:50:07  mdw
  33  * Minor modifications to work with mLib and mgLib.
  34  *
  35  * Revision 1.5  1998/11/30 22:36:53  mdw
  36  * Tidy up tabbing in help texts very slightly.
  37  *
  38  * Revision 1.4  1998/11/21 22:41:19  mdw
  39  * Reap children which die before I get my signal handler installed.
  40  *
  41  * Revision 1.3  1998/11/21 22:30:27  mdw
  42  * Support GNU-style long options throughout, and introduce proper help
  43  * text to all programs.  Update manual pages to match.
  44  *
  45  * Revision 1.2  1998/11/18 21:25:06  mdw
  46  * Reap dead children as they arrive.  The previous shell may have
  47  * carelessly left them behind.
  48  *
  49  * Revision 1.1  1998/11/16 23:00:49  mdw
  50  * Initial versions.
  51  *
  52  */
  53
  54 /*----- Header files ------------------------------------------------------*/
  55
  56 #include <signal.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60
  61 #include <sys/types.h>
  62 #include <sys/wait.h>
  63 #include <unistd.h>
  64
  65 #include <X11/Xlib.h>
  66 #include <X11/Xutil.h>
  67
  68 #include <mLib/mdwopt.h>
  69 #include <mLib/quis.h>
  70
  71 #include "xwait.h"
  72
  73 /*----- Main code ---------------------------------------------------------*/
  74
  75 /* --- @sigchld@ --- */
  76
  77 static void sigchld(int sig)
  78 {
  79   while (waitpid(-1, 0, WNOHANG) > 0)
  80     ;
  81 }
  82
  83 /* --- @main@ --- */
  84
  85 static void version(FILE *fp)
  86 {
  87   fprintf(fp, "%s (xtoys version " VERSION ")\n", QUIS);
  88 }
  89
  90 static void usage(FILE *fp)
  91 {
  92   fprintf(fp, "Usage: %s [-f] [-d DISPLAY] [-a ATOM] [-m MSG]\n", QUIS);
  93 }
  94
  95 int main(int argc, char *argv[])
  96 {
  97   char *display = 0;
  98   Display *dpy;
  99   Atom xwait_die;
 100   XEvent ev;
 101   char *atom = XWAIT_DIE;
 102   char *msg = XWAIT_DIE_MSG;
 103   unsigned f = 0;
 104
 105   enum {
 106     f_force = 1
 107   };
 108
 109   /* --- Parse options --- */
 110
 111   ego(argv[0]);
 112
 113   for (;;) {
 114     static struct option opt[] = {
 115       { "help",         0,                      0,      'h' },
 116       { "usage",        0,                      0,      'u' },
 117       { "version",      0,                      0,      'v' },
 118       { "display",      required_argument,      0,      'd' },
 119       { "atom",         required_argument,      0,      'a' },
 120       { "msg",          required_argument,      0,      'm' },
 121       { "force",        0,                      0,      'f' },
 122       { 0,              0,                      0,      0 }
 123     };
 124
 125     int i = getopt_long(argc, argv, "d:a:m:f", opt, 0);
 126     if (i < 0)
 127       break;
 128     switch (i) {
 129       case 'h':
 130         version(stdout);
 131         fputs("\n", stdout);
 132         usage(stdout);
 133         fputs(
 134 "\n"
 135 "Waits until signalled by `xtell' or `xshutdown'.  Specifically, waits\n"
 136 "until a property with name ATOM is written to the root window with\n"
 137 "contents MSG.\n"
 138 "\n"
 139 "Options:\n"
 140 "\n"
 141 "-h, --help             Display this help text\n"
 142 "-u, --usage            Display a short usage summary\n"
 143 "-v, --version          Display the program's version number\n"
 144 "\n"
 145 "-d, --display=DISPLAY  Choose X display to connect to\n"
 146 "-f, --force            Run even if this property is waited for by another\n"
 147 "                       process\n"
 148 "-a, --atom=ATOM\t      Choose property name to listen for\n"
 149 "-m, --msg=MSG          Choose value of property to wait for\n",
 150           stdout);
 151         exit(0);
 152         break;
 153       case 'u':
 154         usage(stdout);
 155         exit(0);
 156         break;
 157       case 'v':
 158         version(stdout);
 159         exit(0);
 160         break;
 161
 162       case 'd':
 163         display = optarg;
 164         break;
 165       case 'a':
 166         atom = optarg;
 167         break;
 168       case 'm':
 169         msg = optarg;
 170         break;
 171       case 'f':
 172         f |= f_force;
 173         break;
 174       default:
 175         usage(stderr);
 176         exit(EXIT_FAILURE);
 177         break;
 178     }
 179   }
 180
 181   /* --- Connect to the X display --- */
 182
 183   dpy = XOpenDisplay(display);
 184   if (!dpy) {
 185     fprintf(stderr, "xwait: couldn't open display\n");
 186     exit(EXIT_FAILURE);
 187   }
 188
 189   /* --- Fetch the property name atom --- */
 190
 191   xwait_die = XInternAtom(dpy, atom, False);
 192
 193   /* --- Mark ourselves as listening to all the screens --- */
 194
 195   {
 196     int i;
 197     int nsc = ScreenCount(dpy);
 198
 199     /* --- First pass: make sure there's not a process already here --- */
 200
 201     if ((f & f_force) == 0) {
 202       for (i = 0; i < nsc; i++) {
 203         Window win = RootWindow(dpy, i);
 204         XTextProperty prop;
 205
 206         if (XGetTextProperty(dpy, win, &prop, xwait_die)) {
 207           fprintf(stderr, "xwait: already waiting for `%s'\n", atom);
 208           exit(EXIT_FAILURE);
 209         }
 210       }
 211     }
 212
 213     /* --- Second pass: set up listening to the property --- */
 214
 215     for (i = 0; i < nsc; i++) {
 216       Window win = RootWindow(dpy, i);
 217       XTextProperty prop;
 218       char *imsg = "XWAIT_READY";
 219
 220       XStringListToTextProperty(&imsg, 1, &prop);
 221       XSetTextProperty(dpy, win, &prop, xwait_die);
 222       XSelectInput(dpy, win, PropertyChangeMask);
 223     }
 224   }
 225
 226   /* --- Set up a handler when children die --- *
 227    *
 228    * I don't fork any children?  Why is this useful?  Because I've been
 229    * execed from a shell which started lots of background processes, and
 230    * they'll zombie themselves otherwise.
 231    */
 232
 233   {
 234     struct sigaction sa;
 235     sigset_t ss, oss;
 236
 237     /* --- Set the handler up --- */
 238
 239     sa.sa_handler = sigchld;
 240     sigemptyset(&sa.sa_mask);
 241     sigaddset(&sa.sa_mask, SIGCHLD);
 242     sa.sa_flags = 0;
 243     sigaction(SIGCHLD, &sa, 0);
 244
 245     /* --- Now reap any which have been waiting around so far --- */
 246
 247     sigemptyset(&ss);
 248     sigaddset(&ss, SIGCHLD);
 249     sigprocmask(SIG_BLOCK, &ss, &oss);
 250     sigchld(SIGCHLD);
 251     sigprocmask(SIG_SETMASK, &oss, 0);
 252   }
 253
 254   /* --- Now wait for an event --- */
 255
 256   for (;;) {
 257     XNextEvent(dpy, &ev);
 258     switch (ev.type) {
 259       case PropertyNotify:
 260         if (ev.xproperty.atom == xwait_die) {
 261           XTextProperty prop;
 262           char **sl;
 263           int c;
 264
 265           if (XGetTextProperty(dpy, ev.xproperty.window, &prop, xwait_die)) {
 266             XTextPropertyToStringList(&prop, &sl, &c);
 267             if (strcmp(sl[0], msg) == 0)
 268               goto exit;
 269             XFreeStringList(sl);
 270           }
 271         }
 272     }
 273   }
 274
 275   /* --- Finished: remove the property from all the screens --- */
 276
 277 exit:
 278   {
 279     int i;
 280     int nsc = ScreenCount(dpy);
 281
 282     for (i = 0; i < nsc; i++)
 283       XDeleteProperty(dpy, RootWindow(dpy, i), xwait_die);
 284   }
 285
 286   /* --- Go away --- */
 287
 288   XCloseDisplay(dpy);
 289   return (0);
 290 }
 291
 292 /*----- That's all, folks -------------------------------------------------*/