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

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