code.delx.au - pulseaudio/blob - src/polyp/mainloop-signal.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of polypaudio.
   5
   6   polypaudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2 of the License,
   9   or (at your option) any later version.
  10
  11   polypaudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with polypaudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <assert.h>
  28 #include <signal.h>
  29 #include <errno.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <fcntl.h>
  34
  35 #ifdef HAVE_WINDOWS_H
  36 #include <windows.h>
  37 #endif
  38
  39 #include <polypcore/util.h>
  40 #include <polypcore/xmalloc.h>
  41 #include <polypcore/log.h>
  42 #include <polypcore/gccmacro.h>
  43
  44 #include "mainloop-signal.h"
  45
  46 struct pa_signal_event {
  47     int sig;
  48 #ifdef HAVE_SIGACTION
  49     struct sigaction saved_sigaction;
  50 #else
  51     void (*saved_handler)(int sig);
  52 #endif
  53     void (*callback) (pa_mainloop_api*a, pa_signal_event *e, int sig, void *userdata);
  54     void *userdata;
  55     void (*destroy_callback) (pa_mainloop_api*a, pa_signal_event*e, void *userdata);
  56     pa_signal_event *previous, *next;
  57 };
  58
  59 static pa_mainloop_api *api = NULL;
  60 static int signal_pipe[2] = { -1, -1 };
  61 static pa_io_event* io_event = NULL;
  62 static pa_defer_event *defer_event = NULL;
  63 static pa_signal_event *signals = NULL;
  64
  65 #ifdef OS_IS_WIN32
  66 static unsigned int waiting_signals = 0;
  67 static CRITICAL_SECTION crit;
  68 #endif
  69
  70 static void signal_handler(int sig) {
  71 #ifndef HAVE_SIGACTION
  72     signal(sig, signal_handler);
  73 #endif
  74     write(signal_pipe[1], &sig, sizeof(sig));
  75
  76 #ifdef OS_IS_WIN32
  77     EnterCriticalSection(&crit);
  78     waiting_signals++;
  79     LeaveCriticalSection(&crit);
  80 #endif
  81 }
  82
  83 static void dispatch(pa_mainloop_api*a, int sig) {
  84     pa_signal_event*s;
  85
  86     for (s = signals; s; s = s->next)
  87         if (s->sig == sig) {
  88             assert(s->callback);
  89             s->callback(a, s, sig, s->userdata);
  90             break;
  91         }
  92 }
  93
  94 #ifdef OS_IS_WIN32
  95 static void defer(pa_mainloop_api*a, PA_GCC_UNUSED pa_defer_event*e, PA_GCC_UNUSED void *userdata) {
  96     ssize_t r;
  97     int sig;
  98     unsigned int sigs;
  99
 100     EnterCriticalSection(&crit);
 101     sigs = waiting_signals;
 102     waiting_signals = 0;
 103     LeaveCriticalSection(&crit);
 104
 105     while (sigs) {
 106         if ((r = read(signal_pipe[0], &sig, sizeof(sig))) < 0) {
 107             pa_log(__FILE__": read(): %s", strerror(errno));
 108             return;
 109         }
 110
 111         if (r != sizeof(sig)) {
 112             pa_log(__FILE__": short read()");
 113             return;
 114         }
 115
 116         dispatch(a, sig);
 117
 118         sigs--;
 119     }
 120 }
 121 #endif
 122
 123 static void callback(pa_mainloop_api*a, pa_io_event*e, int fd, pa_io_event_flags_t f, PA_GCC_UNUSED void *userdata) {
 124     ssize_t r;
 125     int sig;
 126     assert(a && e && f == PA_IO_EVENT_INPUT && e == io_event && fd == signal_pipe[0]);
 127
 128
 129     if ((r = read(signal_pipe[0], &sig, sizeof(sig))) < 0) {
 130         if (errno == EAGAIN)
 131             return;
 132
 133         pa_log(__FILE__": read(): %s", strerror(errno));
 134         return;
 135     }
 136
 137     if (r != sizeof(sig)) {
 138         pa_log(__FILE__": short read()");
 139         return;
 140     }
 141
 142     dispatch(a, sig);
 143 }
 144
 145 int pa_signal_init(pa_mainloop_api *a) {
 146     assert(!api && a && signal_pipe[0] == -1 && signal_pipe[1] == -1 && !io_event && !defer_event);
 147
 148 #ifdef OS_IS_WIN32
 149     if (_pipe(signal_pipe, 200, _O_BINARY) < 0) {
 150 #else
 151     if (pipe(signal_pipe) < 0) {
 152 #endif
 153         pa_log(__FILE__": pipe() failed: %s", strerror(errno));
 154         return -1;
 155     }
 156
 157     pa_make_nonblock_fd(signal_pipe[0]);
 158     pa_make_nonblock_fd(signal_pipe[1]);
 159     pa_fd_set_cloexec(signal_pipe[0], 1);
 160     pa_fd_set_cloexec(signal_pipe[1], 1);
 161
 162     api = a;
 163
 164 #ifndef OS_IS_WIN32
 165     io_event = api->io_new(api, signal_pipe[0], PA_IO_EVENT_INPUT, callback, NULL);
 166     assert(io_event);
 167 #else
 168     defer_event = api->defer_new(api, defer, NULL);
 169     assert(defer_event);
 170
 171     InitializeCriticalSection(&crit);
 172 #endif
 173
 174     return 0;
 175 }
 176
 177 void pa_signal_done(void) {
 178     assert(api && signal_pipe[0] >= 0 && signal_pipe[1] >= 0 && (io_event || defer_event));
 179
 180     while (signals)
 181         pa_signal_free(signals);
 182
 183 #ifndef OS_IS_WIN32
 184     api->io_free(io_event);
 185     io_event = NULL;
 186 #else
 187     api->defer_free(defer_event);
 188     defer_event = NULL;
 189
 190     DeleteCriticalSection(&crit);
 191 #endif
 192
 193     close(signal_pipe[0]);
 194     close(signal_pipe[1]);
 195     signal_pipe[0] = signal_pipe[1] = -1;
 196
 197     api = NULL;
 198 }
 199
 200 pa_signal_event* pa_signal_new(int sig, void (*_callback) (pa_mainloop_api *api, pa_signal_event*e, int sig, void *userdata), void *userdata) {
 201     pa_signal_event *e = NULL;
 202
 203 #ifdef HAVE_SIGACTION
 204     struct sigaction sa;
 205 #endif
 206
 207     assert(sig > 0 && _callback);
 208
 209     for (e = signals; e; e = e->next)
 210         if (e->sig == sig)
 211             goto fail;
 212
 213     e = pa_xmalloc(sizeof(pa_signal_event));
 214     e->sig = sig;
 215     e->callback = _callback;
 216     e->userdata = userdata;
 217     e->destroy_callback = NULL;
 218
 219 #ifdef HAVE_SIGACTION
 220     memset(&sa, 0, sizeof(sa));
 221     sa.sa_handler = signal_handler;
 222     sigemptyset(&sa.sa_mask);
 223     sa.sa_flags = SA_RESTART;
 224
 225     if (sigaction(sig, &sa, &e->saved_sigaction) < 0)
 226 #else
 227     if ((e->saved_handler = signal(sig, signal_handler)) == SIG_ERR)
 228 #endif
 229         goto fail;
 230
 231     e->previous = NULL;
 232     e->next = signals;
 233     signals = e;
 234
 235     return e;
 236 fail:
 237     if (e)
 238         pa_xfree(e);
 239     return NULL;
 240 }
 241
 242 void pa_signal_free(pa_signal_event *e) {
 243     assert(e);
 244
 245     if (e->next)
 246         e->next->previous = e->previous;
 247     if (e->previous)
 248         e->previous->next = e->next;
 249     else
 250         signals = e->next;
 251
 252 #ifdef HAVE_SIGACTION
 253     sigaction(e->sig, &e->saved_sigaction, NULL);
 254 #else
 255     signal(e->sig, e->saved_handler);
 256 #endif
 257
 258     if (e->destroy_callback)
 259         e->destroy_callback(api, e, e->userdata);
 260
 261     pa_xfree(e);
 262 }
 263
 264 void pa_signal_set_destroy(pa_signal_event *e, void (*_callback) (pa_mainloop_api *api, pa_signal_event*e, void *userdata)) {
 265     assert(e);
 266     e->destroy_callback = _callback;
 267 }