ref: e4aa75977e5a2e7ace5e7742193cfef427adaa77
dir: /pcsound/pcsound_bsd.c/
// Emacs style mode select -*- C++ -*- //----------------------------------------------------------------------------- // // Copyright(C) 2007 Simon Howard // // 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. // // DESCRIPTION: // PC speaker driver for [Open]BSD // (Should be NetBSD as well, but untested). // //----------------------------------------------------------------------------- #include "config.h" // OpenBSD/NetBSD: #ifdef HAVE_DEV_ISA_SPKRIO_H #define HAVE_BSD_SPEAKER #include <dev/isa/spkrio.h> #endif // FreeBSD #ifdef HAVE_DEV_SPEAKER_SPEAKER_H #define HAVE_BSD_SPEAKER #include <dev/speaker/speaker.h> #endif #ifdef HAVE_BSD_SPEAKER #include <stdio.h> #include <stdlib.h> #include <string.h> #include <errno.h> #include <signal.h> #include <sys/ioctl.h> #include <sys/signal.h> #include <sys/socket.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <fcntl.h> #include "SDL.h" #include "SDL_thread.h" #include "pcsound.h" #include "pcsound_internal.h" #define SPEAKER_DEVICE "/dev/speaker" // // This driver is far more complicated than it should be, because // OpenBSD has sucky support for threads. Because multithreading // is done in userspace, invoking the ioctl to make the speaker // beep will lock all threads until the beep has completed. // // Thus, to get the beeping to occur in real-time, we must invoke // the ioctl in a separate process. To do this, a separate // sound server is forked that listens on a socket for tones to // play. When a tone is received, a reply is sent back to the // main process and the tone played. // // Meanwhile, back in the main process, there is a sound thread // that runs, invoking the pcsound callback function to get // more tones. This blocks on the sound server socket, waiting // for replies. In this way, when the sound server finishes // playing a tone, the next one is sent. // // This driver is a bit less accurate than the others, because // we can only specify sound durations in 1/100ths of a second, // as opposed to the normal millisecond durations. static pcsound_callback_func callback; static int sound_server_pid; static int sleep_adjust = 0; static int sound_thread_running; static SDL_Thread *sound_thread_handle; static int sound_server_pipe[2]; // Play a sound, checking how long the system call takes to complete // and autoadjusting for drift. static void AdjustedBeep(int speaker_handle, int ms, int freq) { unsigned int start_time; unsigned int end_time; unsigned int actual_time; tone_t tone; // Adjust based on previous error to keep the tempo right if (sleep_adjust > ms) { sleep_adjust -= ms; return; } else { ms -= sleep_adjust; } // Invoke the system call and time how long it takes start_time = SDL_GetTicks(); tone.duration = ms / 10; // in 100ths of a second tone.frequency = freq; // Always a positive duration if (tone.duration < 1) { tone.duration = 1; } if (ioctl(speaker_handle, SPKRTONE, &tone) != 0) { perror("ioctl"); return; } end_time = SDL_GetTicks(); if (end_time > start_time) { actual_time = end_time - start_time; } else { actual_time = ms; } if (actual_time < ms) { actual_time = ms; } // Save sleep_adjust for next time sleep_adjust = actual_time - ms; } static void SoundServer(int speaker_handle) { tone_t tone; int result; // Run in a loop, invoking the callback for (;;) { result = read(sound_server_pipe[1], &tone, sizeof(tone_t)); if (result < 0) { perror("read"); return; } // Send back a response, so the main process knows to send another write(sound_server_pipe[1], &tone, sizeof(tone_t)); // Beep! (blocks until complete) AdjustedBeep(speaker_handle, tone.duration, tone.frequency); } } // Start up the sound server. Returns non-zero if successful. static int StartSoundServer(void) { int result; int speaker_handle; // Try to open the speaker device speaker_handle = open(SPEAKER_DEVICE, O_WRONLY); if (speaker_handle == -1) { // Don't have permissions for the console device? fprintf(stderr, "StartSoundServer: Failed to open '%s': %s\n", SPEAKER_DEVICE, strerror(errno)); return 0; } // Create a pipe for communications if (socketpair(AF_UNIX, SOCK_STREAM, 0, sound_server_pipe) < 0) { perror("socketpair"); close(speaker_handle); return 0; } // Start a separate process to generate PC speaker output // We can't use the SDL threading functions because OpenBSD's // threading sucks :-( result = fork(); if (result < 0) { fprintf(stderr, "Failed to fork sound server!\n"); close(speaker_handle); return 0; } else if (result == 0) { // This is the child (sound server) SoundServer(speaker_handle); close(speaker_handle); exit(0); } else { // This is the parent sound_server_pid = result; } return 1; } static void StopSoundServer(void) { int status; kill(sound_server_pid, SIGINT); waitpid(sound_server_pid, &status, 0); } static int SoundThread(void *unused) { tone_t tone; int duration; int frequency; while (sound_thread_running) { // Get the next frequency to play callback(&duration, &frequency); //printf("dur: %i, freq: %i\n", duration, frequency); // Build up a tone structure and send to the sound server tone.frequency = frequency; tone.duration = duration; if (write(sound_server_pipe[0], &tone, sizeof(tone_t)) < 0) { perror("write"); break; } // Wait until the sound server responds before sending another if (read(sound_server_pipe[0], &tone, sizeof(tone_t)) < 0) { perror("read"); break; } } return 0; } static int PCSound_BSD_Init(pcsound_callback_func callback_func) { callback = callback_func; if (!StartSoundServer()) { fprintf(stderr, "PCSound_BSD_Init: Failed to start sound server.\n"); return 0; } sound_thread_running = 1; sound_thread_handle = SDL_CreateThread(SoundThread, NULL); return 1; } static void PCSound_BSD_Shutdown(void) { // Stop the sound thread sound_thread_running = 0; SDL_WaitThread(sound_thread_handle, NULL); // Stop the sound server StopSoundServer(); } pcsound_driver_t pcsound_bsd_driver = { "BSD", PCSound_BSD_Init, PCSound_BSD_Shutdown, }; #endif /* #ifdef HAVE_BSD_SPEAKER */