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

   1 /* -*-c-*-
   2  *
   3  * $Id: xwait.c,v 1.10 2004/04/08 01:36:29 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 /*----- Header files ------------------------------------------------------*/
  30
  31 #include <errno.h>
  32 #include <signal.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include <sys/types.h>
  38 #include <sys/wait.h>
  39 #include <unistd.h>
  40
  41 #include <X11/Xlib.h>
  42 #include <X11/Xutil.h>
  43
  44 #include <mLib/mdwopt.h>
  45 #include <mLib/quis.h>
  46 #include <mLib/report.h>
  47 #include <mLib/sub.h>
  48
  49 #include "xatom.h"
  50 #include "xwait.h"
  51
  52 /*----- Data structures ---------------------------------------------------*/
  53
  54 typedef struct xwait_msg {
  55   struct xwait_msg *next;               /* Next message in the list */
  56   Atom a;                               /* The message atom */
  57 } xwait_msg;
  58
  59 typedef struct xwait_atom {
  60   struct xwait_atom *next;              /* Next atom in the list */
  61   Atom a;                               /* The actual atom */
  62   xwait_msg *m;                         /* List of interesting messages */
  63 } xwait_atom;
  64
  65 /*----- Static variables --------------------------------------------------*/
  66
  67 static xwait_atom *atoms = 0;
  68 static Display *dpy;
  69
  70 /*----- Main code ---------------------------------------------------------*/
  71
  72 /* --- @sigchld@ --- */
  73
  74 static void sigchld(int sig)
  75 {
  76   int e = errno;
  77   while (waitpid(-1, 0, WNOHANG) > 0)
  78     ;
  79   errno = e;
  80 }
  81
  82 /* --- @opendisplay@ --- */
  83
  84 static void opendisplay(const char *d)
  85 {
  86   if (dpy)
  87     return;
  88   if ((dpy = XOpenDisplay(d)) == 0)
  89     die(EXIT_FAILURE, "couldn't open display");
  90 }
  91
  92 /* --- @addatom@ --- */
  93
  94 static xwait_atom *addatom(const char *a)
  95 {
  96   xwait_atom *xa = CREATE(xwait_atom);
  97   opendisplay(0);
  98   xa->next = atoms;
  99   xa->a = XInternAtom(dpy, a, False);
 100   xa->m = 0;
 101   atoms = xa;
 102   return (xa);
 103 }
 104
 105 /* --- @addmsg@ --- */
 106
 107 static void addmsg(xwait_atom *xa, const char *a)
 108 {
 109   xwait_msg *xm = CREATE(xwait_msg);
 110   opendisplay(0);
 111   xm->next = xa->m;
 112   xm->a = XInternAtom(dpy, a, False);
 113   xa->m = xm;
 114 }
 115
 116 /* --- @tidy@ --- */
 117
 118 static void tidy(int sig)
 119 {
 120   int i;
 121   int nsc = ScreenCount(dpy);
 122   xwait_atom *xa;
 123
 124   for (i = 0; i < nsc; i++) {
 125     for (xa = atoms; xa; xa = xa->next)
 126       XDeleteProperty(dpy, RootWindow(dpy, i), xa->a);
 127   }
 128   XCloseDisplay(dpy);
 129   exit(0);
 130 }
 131
 132 /* --- @main@ --- */
 133
 134 static void version(FILE *fp)
 135 {
 136   fprintf(fp, "%s (xtoys version " VERSION ")\n", QUIS);
 137 }
 138
 139 static void usage(FILE *fp)
 140 {
 141   fprintf(fp, "Usage: %s [-f] [-d DISPLAY] [ATOM:MSG,MSG]...\n", QUIS);
 142 }
 143
 144 int main(int argc, char *argv[])
 145 {
 146   Atom a;
 147   XEvent ev;
 148   unsigned f = 0;
 149   xwait_atom *xa = 0;
 150   xwait_msg *xm = 0;
 151
 152 #define f_force 1u
 153
 154   /* --- Initialize mLib --- */
 155
 156   ego(argv[0]);
 157   sub_init();
 158
 159   /* --- Parse options --- */
 160
 161   for (;;) {
 162     static struct option opt[] = {
 163       { "help",         0,                      0,      'h' },
 164       { "usage",        0,                      0,      'u' },
 165       { "version",      0,                      0,      'v' },
 166       { "display",      OPTF_ARGREQ,            0,      'd' },
 167       { "atom",         OPTF_ARGREQ,            0,      'a' },
 168       { "msg",          OPTF_ARGREQ,            0,      'm' },
 169       { "force",        0,                      0,      'f' },
 170       { 0,              0,                      0,      0 }
 171     };
 172
 173     int i = mdwopt(argc, argv, "huvd:a:m:f", opt, 0, 0, 0);
 174     if (i < 0)
 175       break;
 176     switch (i) {
 177       case 'h':
 178         version(stdout);
 179         fputs("\n", stdout);
 180         usage(stdout);
 181         fputs(
 182 "\n"
 183 "Waits until signalled by `xtell' or `xshutdown'.  Specifically, waits\n"
 184 "until a property with name ATOM is written to the root window with\n"
 185 "contents MSG.\n"
 186 "\n"
 187 "Options:\n"
 188 "\n"
 189 "-h, --help             Display this help text\n"
 190 "-u, --usage            Display a short usage summary\n"
 191 "-v, --version          Display the program's version number\n"
 192 "\n"
 193 "-d, --display=DISPLAY  Choose X display to connect to\n"
 194 "-f, --force            Run even if this property is waited for by another\n"
 195 "                       process\n"
 196 "-a, --atom=ATOM\t      Choose property name to listen for [deprecated]\n"
 197 "-m, --msg=MSG          Choose value of property to wait for [deprecated]\n",
 198           stdout);
 199         exit(0);
 200         break;
 201       case 'u':
 202         usage(stdout);
 203         exit(0);
 204         break;
 205       case 'v':
 206         version(stdout);
 207         exit(0);
 208         break;
 209
 210       case 'd':
 211         opendisplay(optarg);
 212         break;
 213       case 'a':
 214         xa = addatom(optarg);
 215         break;
 216       case 'm':
 217         if (!xa)
 218           die(EXIT_FAILURE, "no atom currently defined");
 219         addmsg(xa, optarg);
 220         break;
 221       case 'f':
 222         f |= f_force;
 223         break;
 224       default:
 225         usage(stderr);
 226         exit(EXIT_FAILURE);
 227         break;
 228     }
 229   }
 230
 231   /* --- Grind through remaining arguments in the new syntax --- */
 232
 233   while (optind < argc) {
 234     char *p = strtok(argv[optind++], ":");
 235     if (!p)
 236       continue;
 237     xa = addatom(p);
 238     while ((p = strtok(0, ",")) != 0)
 239       addmsg(xa, p);
 240   }
 241
 242   /* --- If there's nothing set, put in some defaults --- */
 243
 244   if (!atoms) {
 245     xa = addatom(XWAIT_DIE);
 246     addmsg(xa, XWAIT_DIE_MSG);
 247   }
 248
 249   /* --- Attach the atoms to the screens --- */
 250
 251   {
 252     int i;
 253     Atom ready = XInternAtom(dpy, "XWAIT_READY", False);
 254     int nsc = ScreenCount(dpy);
 255
 256     /* --- First pass: make sure there's not a process already here --- */
 257
 258     if ((f & f_force) == 0) {
 259       for (i = 0; i < nsc; i++) {
 260         for (xa = atoms; xa; xa = xa->next) {
 261           if (xatom_get(dpy, RootWindow(dpy, i), xa->a) != None)
 262             die(EXIT_FAILURE, "already waiting for `%s'");
 263         }
 264       }
 265     }
 266
 267     /* --- Second pass: set up listening to the property --- */
 268
 269     for (i = 0; i < nsc; i++) {
 270       for (xa = atoms; xa; xa = xa->next)
 271         xatom_set(dpy, RootWindow(dpy, i), xa->a, ready);
 272       XSelectInput(dpy, RootWindow(dpy, i), PropertyChangeMask);
 273     }
 274   }
 275
 276   /* --- Set up a handler when children die --- *
 277    *
 278    * I don't fork any children?  Why is this useful?  Because I've been
 279    * execed from a shell which started lots of background processes, and
 280    * they'll zombie themselves otherwise.
 281    */
 282
 283   {
 284     struct sigaction sa;
 285
 286     sa.sa_handler = sigchld;
 287     sigemptyset(&sa.sa_mask);
 288     sigaddset(&sa.sa_mask, SIGCHLD);
 289     sa.sa_flags = SA_NOCLDSTOP;
 290 #ifdef SA_RESTART
 291     sa.sa_flags |= SA_RESTART;
 292 #endif
 293     sigaction(SIGCHLD, &sa, 0);
 294   }
 295
 296   /* --- Now reap any which have been waiting around so far --- */
 297
 298   {
 299     sigset_t ss, oss;
 300
 301     sigemptyset(&ss);
 302     sigaddset(&ss, SIGCHLD);
 303     sigprocmask(SIG_BLOCK, &ss, &oss);
 304     sigchld(SIGCHLD);
 305     sigprocmask(SIG_SETMASK, &oss, 0);
 306   }
 307
 308   signal(SIGINT, tidy);
 309   signal(SIGTERM, tidy);
 310
 311   /* --- Now wait for an event --- */
 312
 313   for (;;) {
 314     XNextEvent(dpy, &ev);
 315     switch (ev.type) {
 316       case PropertyNotify:
 317         for (xa = atoms; xa; xa = xa->next) {
 318           if (ev.xproperty.atom != xa->a)
 319             continue;
 320           a = xatom_get(dpy, ev.xproperty.window, xa->a);
 321           if (a == None)
 322             continue;
 323           if (xa->m == 0)
 324             goto exit;
 325           for (xm = xa->m; xm; xm = xm->next) {
 326             if (a == xm->a)
 327               goto exit;
 328           }
 329         }
 330         break;
 331     }
 332   }
 333
 334   /* --- Finished: report the result if necessary --- */
 335
 336 exit:
 337   if (atoms->next) {
 338     fputs(XGetAtomName(dpy, xa->a), stdout);
 339     if (!xa->m || xa->m->next)
 340       printf(": %s\n", XGetAtomName(dpy, a));
 341     else
 342       fputc('\n', stdout);
 343   } else if (!xa->m || xa->m->next)
 344     printf("%s\n", XGetAtomName(dpy, a));
 345
 346   /* --- Go away --- */
 347
 348   tidy(0);
 349   return (0);
 350 }
 351
 352 /*----- That's all, folks -------------------------------------------------*/