workspace/kdm/backend/reset.c

   1 /*
   2
   3 Copyright 1988, 1998  The Open Group
   4
   5 Permission to use, copy, modify, distribute, and sell this software and its
   6 documentation for any purpose is hereby granted without fee, provided that
   7 the above copyright notice appear in all copies and that both that
   8 copyright notice and this permission notice appear in supporting
   9 documentation.
  10
  11 The above copyright notice and this permission notice shall be included
  12 in all copies or substantial portions of the Software.
  13
  14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  15 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  16 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  17 IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18 OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20 OTHER DEALINGS IN THE SOFTWARE.
  21
  22 Except as contained in this notice, the name of a copyright holder shall
  23 not be used in advertising or otherwise to promote the sale, use or
  24 other dealings in this Software without prior written authorization
  25 from the copyright holder.
  26
  27 */
  28
  29 /*
  30  * xdm - display manager daemon
  31  * Author: Keith Packard, MIT X Consortium
  32  *
  33  * pseudoReset -- pretend to reset the server by killing all clients
  34  * with windows.  It will reset the server most of the time, unless
  35  * a client remains connected with no windows.
  36  */
  37
  38 #include "dm.h"
  39 #include "dm_error.h"
  40
  41 #include <X11/Xlib.h>
  42
  43 #include <signal.h>
  44
  45 /*ARGSUSED*/
  46 static int
  47 ignoreErrors( Display *dspl ATTR_UNUSED, XErrorEvent *event ATTR_UNUSED )
  48 {
  49         debug( "ignoring error\n" );
  50         return False;
  51 }
  52
  53 /*
  54  * this is mostly bogus -- but quite useful.  I wish the protocol
  55  * had some way of enumerating and identifying clients, that way
  56  * this code wouldn't have to be this kludgy.
  57  */
  58
  59 static void
  60 killWindows( Window window )
  61 {
  62         Window root, parent, *children;
  63         unsigned int child, nchildren = 0;
  64
  65         while (XQueryTree( dpy, window, &root, &parent, &children, &nchildren ) &&
  66                nchildren > 0)
  67         {
  68                 for (child = 0; child < nchildren; child++) {
  69                         debug( "XKillClient %p\n", children[child] );
  70                         XKillClient( dpy, children[child] );
  71                 }
  72                 XFree( (char *)children );
  73         }
  74 }
  75
  76 static Jmp_buf resetJmp;
  77
  78 /* ARGSUSED */
  79 static void
  80 abortReset( int n ATTR_UNUSED )
  81 {
  82         Longjmp( resetJmp, 1 );
  83 }
  84
  85 /*
  86  * this display connection better not have any windows...
  87  */
  88
  89 void
  90 pseudoReset()
  91 {
  92         int screen;
  93
  94         if (Setjmp( resetJmp )) {
  95                 logError( "pseudoReset timeout\n" );
  96         } else {
  97                 (void)Signal( SIGALRM, abortReset );
  98                 (void)alarm( 30 );
  99                 XSetErrorHandler( ignoreErrors );
 100                 for (screen = 0; screen < ScreenCount (dpy); screen++) {
 101                         debug( "pseudoReset screen %d\n", screen );
 102                         killWindows( RootWindow( dpy, screen ) );
 103                 }
 104                 debug( "before XSync\n" );
 105                 XSync( dpy, False );
 106                 (void)alarm( 0 );
 107         }
 108         Signal( SIGALRM, SIG_DFL );
 109         XSetErrorHandler( (XErrorHandler)0 );
 110         debug( "pseudoReset done\n" );
 111 }