/* the Music Player Daemon (MPD) * Copyright (C) 2003-2007 Warren Dukes <warren.dukes@gmail.com> * Copyright (C) 2008 Eric Wong <normalperson@yhbt.net> * * This project's homepage is: http://www.musicpd.org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "main_notify.h" #include "notify.h" #include "utils.h" #include "ioops.h" #include "gcc.h" #include "log.h" static struct ioOps main_notify_IO; static int main_pipe[2]; static pthread_t main_task; static pthread_cond_t main_wakeup = PTHREAD_COND_INITIALIZER; static pthread_mutex_t main_wakeup_mutex = PTHREAD_MUTEX_INITIALIZER; static pthread_mutex_t select_mutex = PTHREAD_MUTEX_INITIALIZER; static int ioops_fdset(fd_set * rfds, mpd_unused fd_set * wfds, mpd_unused fd_set * efds) { FD_SET(main_pipe[0], rfds); return main_pipe[0]; } static void consume_pipe(void) { char buffer[2]; ssize_t r = read(main_pipe[0], buffer, sizeof(buffer)); if (r < 0 && errno != EAGAIN && errno != EINTR) FATAL("error reading from pipe: %s\n", strerror(errno)); } static int ioops_consume(int fd_count, fd_set * rfds, mpd_unused fd_set * wfds, mpd_unused fd_set * efds) { if (FD_ISSET(main_pipe[0], rfds)) { consume_pipe(); FD_CLR(main_pipe[0], rfds); fd_count--; } return fd_count; } void init_main_notify(void) { if (pipe(main_pipe) < 0) FATAL("Couldn't open pipe: %s", strerror(errno)); if (set_nonblocking(main_pipe[0]) < 0) FATAL("Couldn't set non-blocking on main_notify fd: %s", strerror(errno)); if (set_nonblocking(main_pipe[1]) < 0) FATAL("Couldn't set non-blocking on main_notify fd: %s", strerror(errno)); main_notify_IO.fdset = ioops_fdset; main_notify_IO.consume = ioops_consume; registerIO(&main_notify_IO); main_task = pthread_self(); } static int wakeup_via_pipe(void) { int ret = pthread_mutex_trylock(&select_mutex); if (ret == EBUSY) { ssize_t w = write(main_pipe[1], "", 1); if (w < 0 && errno != EAGAIN && errno != EINTR) FATAL("error writing to pipe: %s\n", strerror(errno)); return 1; } else { pthread_mutex_unlock(&select_mutex); return 0; } } void wakeup_main_task(void) { assert(!pthread_equal(main_task, pthread_self())); if (!wakeup_via_pipe()) pthread_cond_signal(&main_wakeup); } void main_notify_lock(void) { assert(pthread_equal(main_task, pthread_self())); pthread_mutex_lock(&select_mutex); } void main_notify_unlock(void) { assert(pthread_equal(main_task, pthread_self())); pthread_mutex_unlock(&select_mutex); } void wait_main_task(void) { assert(pthread_equal(main_task, pthread_self())); pthread_mutex_lock(&main_wakeup_mutex); pthread_cond_wait(&main_wakeup, &main_wakeup_mutex); pthread_mutex_unlock(&main_wakeup_mutex); }