hw/dmx/input/dmxsigio.c

   1 /*
   2  * Copyright 2002-2003 Red Hat Inc., Durham, North Carolina.
   3  *
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining
   7  * a copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation on the rights to use, copy, modify, merge,
  10  * publish, distribute, sublicense, and/or sell copies of the Software,
  11  * and to permit persons to whom the Software is furnished to do so,
  12  * subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial
  16  * portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  21  * NON-INFRINGEMENT.  IN NO EVENT SHALL RED HAT AND/OR THEIR SUPPLIERS
  22  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  23  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  25  * SOFTWARE.
  26  */
  27
  28 /*
  29  * Authors:
  30  *   Rickard E. (Rik) Faith <faith@redhat.com>
  31  *
  32  */
  33
  34 /** \file
  35  *
  36  * Provides an interface for handling SIGIO signals for input devices. */
  37
  38 #ifdef HAVE_DMX_CONFIG_H
  39 #include <dmx-config.h>
  40 #endif
  41
  42 #include "inputstr.h"
  43 #include "dmxinputinit.h"
  44 #include "dmxsigio.h"
  45 #include "dmxevents.h"
  46 #include <signal.h>
  47 #include <unistd.h>
  48 #include <fcntl.h>
  49
  50 static int dmxFdCount = 0;
  51 static Bool dmxInputEnabled = TRUE;
  52
  53 /* Define equivalents for non-POSIX systems (e.g., SGI IRIX, Solaris) */
  54 #ifndef O_ASYNC
  55 #ifdef FASYNC
  56 #define O_ASYNC FASYNC
  57 #else
  58 #define O_ASYNC 0
  59 #endif
  60 #endif
  61 #ifndef O_NONBLOCK
  62 #define O_NONBLOCK FNONBLK
  63 #endif
  64
  65 static void
  66 dmxSigioHandler(int sig)
  67 {
  68     int i, j;
  69     DMXInputInfo *dmxInput;
  70
  71     for (i = 0, dmxInput = &dmxInputs[0]; i < dmxNumInputs; i++, dmxInput++) {
  72         if (dmxInput->sigioState == DMX_ACTIVESIGIO) {
  73             for (j = 0; j < dmxInput->numDevs; j++) {
  74                 DMXLocalInputInfoPtr dmxLocal = dmxInput->devs[j];
  75
  76                 if (dmxLocal->collect_events) {
  77                     dmxLocal->collect_events(&dmxLocal->pDevice->public,
  78                                              dmxMotion,
  79                                              dmxEnqueue,
  80                                              dmxCheckSpecialKeys, DMX_NO_BLOCK);
  81                 }
  82             }
  83         }
  84     }
  85 }
  86
  87 static void
  88 dmxSigioHook(void)
  89 {
  90     struct sigaction a;
  91     sigset_t s;
  92
  93     memset(&a, 0, sizeof(a));
  94     a.sa_handler = dmxSigioHandler;
  95     sigemptyset(&a.sa_mask);
  96     sigaddset(&a.sa_mask, SIGIO);
  97     sigaddset(&a.sa_mask, SIGALRM);
  98     sigaddset(&a.sa_mask, SIGVTALRM);
  99     sigaction(SIGIO, &a, 0);
 100
 101     sigemptyset(&s);
 102     sigprocmask(SIG_SETMASK, &s, 0);
 103 }
 104
 105 static void
 106 dmxSigioUnhook(void)
 107 {
 108     struct sigaction a;
 109
 110     memset(&a, 0, sizeof(a));
 111     a.sa_handler = SIG_IGN;
 112     sigemptyset(&a.sa_mask);
 113     sigaction(SIGIO, &a, 0);
 114 }
 115
 116 static void
 117 dmxSigioAdd(DMXInputInfo * dmxInput)
 118 {
 119     int flags;
 120     int i;
 121
 122     switch (dmxInput->sigioState) {
 123     case DMX_NOSIGIO:
 124         return;
 125     case DMX_USESIGIO:
 126         dmxInput->sigioState = DMX_ACTIVESIGIO;
 127         break;
 128     case DMX_ACTIVESIGIO:
 129         return;
 130     }
 131
 132     for (i = 0; i < dmxInput->sigioFdCount; i++) {
 133         if (!dmxInput->sigioAdded[i]) {
 134             int fd = dmxInput->sigioFd[i];
 135
 136             fcntl(fd, F_SETOWN, getpid());
 137             flags = fcntl(fd, F_GETFL);
 138             flags |= O_ASYNC | O_NONBLOCK;
 139             fcntl(fd, F_SETFL, flags);
 140
 141             AddEnabledDevice(fd);
 142             dmxInput->sigioAdded[i] = TRUE;
 143
 144             if (++dmxFdCount == 1)
 145                 dmxSigioHook();
 146         }
 147     }
 148 }
 149
 150 static void
 151 dmxSigioRemove(DMXInputInfo * dmxInput)
 152 {
 153     int flags;
 154     int i;
 155
 156     switch (dmxInput->sigioState) {
 157     case DMX_NOSIGIO:
 158         return;
 159     case DMX_USESIGIO:
 160         return;
 161     case DMX_ACTIVESIGIO:
 162         dmxInput->sigioState = DMX_USESIGIO;
 163         break;
 164     }
 165
 166     for (i = 0; i < dmxInput->sigioFdCount; i++) {
 167         if (dmxInput->sigioAdded[i]) {
 168             int fd = dmxInput->sigioFd[i];
 169
 170             dmxInput->sigioAdded[i] = FALSE;
 171             RemoveEnabledDevice(fd);
 172
 173             flags = fcntl(fd, F_GETFL);
 174             flags &= ~(O_ASYNC | O_NONBLOCK);
 175             fcntl(fd, F_SETFL, flags);
 176
 177             if (!--dmxFdCount)
 178                 dmxSigioUnhook();
 179         }
 180     }
 181 }
 182
 183 /** Enable SIGIO handling.  This instantiates the handler with the OS. */
 184 void
 185 dmxSigioEnableInput(void)
 186 {
 187     int i;
 188     DMXInputInfo *dmxInput;
 189
 190     dmxInputEnabled = TRUE;
 191     for (i = 0, dmxInput = &dmxInputs[0]; i < dmxNumInputs; i++, dmxInput++)
 192         dmxSigioAdd(dmxInput);
 193 }
 194
 195 /** Disable SIGIO handling.  This removes the hanlder from the OS. */
 196 void
 197 dmxSigioDisableInput(void)
 198 {
 199     int i;
 200     DMXInputInfo *dmxInput;
 201
 202     dmxInputEnabled = FALSE;
 203     for (i = 0, dmxInput = &dmxInputs[0]; i < dmxNumInputs; i++, dmxInput++)
 204         dmxSigioRemove(dmxInput);
 205 }
 206
 207 /** Make a note that the input device described in \a dmxInput will be
 208  * using the file descriptor \a fd for SIGIO signals.  Calls
 209  * AddEnabledDevice ifi SIGIO handling has been enabled with
 210  * #dmxSigioEnableInput(). */
 211 void
 212 dmxSigioRegister(DMXInputInfo * dmxInput, int fd)
 213 {
 214     dmxInput->sigioState = DMX_USESIGIO;
 215     if (dmxInput->sigioFdCount >= DMX_MAX_SIGIO_FDS)
 216         dmxLog(dmxFatal, "Too many SIGIO file descriptors (%d >= %d)\n",
 217                dmxInput->sigioFdCount, DMX_MAX_SIGIO_FDS);
 218
 219     dmxInput->sigioFd[dmxInput->sigioFdCount++] = fd;
 220     if (dmxInputEnabled)
 221         dmxSigioAdd(dmxInput);
 222 }
 223
 224 /** Remove the notes that \a dmxInput is using any file descriptors for
 225  * SIGIO signals.  Calls RemoveEnabledDevice. */
 226 void
 227 dmxSigioUnregister(DMXInputInfo * dmxInput)
 228 {
 229     if (dmxInput->sigioState == DMX_NOSIGIO)
 230         return;
 231     dmxSigioRemove(dmxInput);
 232     dmxInput->sigioState = DMX_NOSIGIO;
 233     dmxInput->sigioFdCount = 0;
 234 }