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

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