src/audioOutputs/audioOutput_fifo.c

   1 /* the Music Player Daemon (MPD)
   2  * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
   3  * This project's homepage is: http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include "../audioOutput.h"
  20
  21 #include <stdlib.h>
  22
  23 #ifdef HAVE_FIFO
  24
  25 #include "../log.h"
  26 #include "../conf.h"
  27 #include "../utils.h"
  28 #include "../timer.h"
  29
  30 #include <errno.h>
  31 #include <fcntl.h>
  32 #include <string.h>
  33 #include <unistd.h>
  34 #include <sys/stat.h>
  35 #include <sys/types.h>
  36
  37 #define FIFO_BUFFER_SIZE 65536 /* pipe capacity on Linux >= 2.6.11 */
  38
  39 typedef struct _FifoData {
  40         char *path;
  41         int input;
  42         int output;
  43         int created;
  44         Timer *timer;
  45 } FifoData;
  46
  47 static FifoData *newFifoData()
  48 {
  49         FifoData *ret;
  50
  51         ret = xmalloc(sizeof(FifoData));
  52
  53         ret->path = NULL;
  54         ret->input = -1;
  55         ret->output = -1;
  56         ret->created = 0;
  57         ret->timer = NULL;
  58
  59         return ret;
  60 }
  61
  62 static void freeFifoData(FifoData *fd)
  63 {
  64         if (fd->path)
  65                 free(fd->path);
  66
  67         if (fd->timer)
  68                 timer_free(fd->timer);
  69
  70         free(fd);
  71 }
  72
  73 static void removeFifo(FifoData *fd)
  74 {
  75         DEBUG("Removing FIFO \"%s\"\n", fd->path);
  76
  77         if (unlink(fd->path) < 0) {
  78                 ERROR("Could not remove FIFO \"%s\": %s\n",
  79                       fd->path, strerror(errno));
  80                 return;
  81         }
  82
  83         fd->created = 0;
  84 }
  85
  86 static void closeFifo(FifoData *fd)
  87 {
  88         struct stat st;
  89
  90         if (fd->input >= 0) {
  91                 close(fd->input);
  92                 fd->input = -1;
  93         }
  94
  95         if (fd->output >= 0) {
  96                 close(fd->output);
  97                 fd->output = -1;
  98         }
  99
 100         if (fd->created && (stat(fd->path, &st) == 0))
 101                 removeFifo(fd);
 102 }
 103
 104 static int makeFifo(FifoData *fd)
 105 {
 106         if (mkfifo(fd->path, 0666) < 0) {
 107                 ERROR("Couldn't create FIFO \"%s\": %s\n",
 108                       fd->path, strerror(errno));
 109                 return -1;
 110         }
 111
 112         fd->created = 1;
 113
 114         return 0;
 115 }
 116
 117 static int checkFifo(FifoData *fd)
 118 {
 119         struct stat st;
 120
 121         if (stat(fd->path, &st) < 0) {
 122                 if (errno == ENOENT) {
 123                         /* Path doesn't exist */
 124                         return makeFifo(fd);
 125                 }
 126
 127                 ERROR("Failed to stat FIFO \"%s\": %s\n",
 128                       fd->path, strerror(errno));
 129                 return -1;
 130         }
 131
 132         if (!S_ISFIFO(st.st_mode)) {
 133                 ERROR("\"%s\" already exists, but is not a FIFO\n", fd->path);
 134                 return -1;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static int openFifo(FifoData *fd)
 141 {
 142         if (checkFifo(fd) < 0)
 143                 return -1;
 144
 145         fd->input = open(fd->path, O_RDONLY|O_NONBLOCK);
 146         if (fd->input < 0) {
 147                 ERROR("Could not open FIFO \"%s\" for reading: %s\n",
 148                       fd->path, strerror(errno));
 149                 closeFifo(fd);
 150                 return -1;
 151         }
 152
 153         fd->output = open(fd->path, O_WRONLY|O_NONBLOCK);
 154         if (fd->output < 0) {
 155                 ERROR("Could not open FIFO \"%s\" for writing: %s\n",
 156                       fd->path, strerror(errno));
 157                 closeFifo(fd);
 158                 return -1;
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int fifo_initDriver(AudioOutput *audioOutput, ConfigParam *param)
 165 {
 166         FifoData *fd;
 167         BlockParam *blockParam;
 168         char *path;
 169
 170         blockParam = getBlockParam(param, "path");
 171         if (!blockParam) {
 172                 FATAL("No \"path\" parameter specified for fifo output "
 173                       "defined at line %i\n", param->line);
 174         }
 175
 176         path = parsePath(blockParam->value);
 177         if (!path) {
 178                 FATAL("Could not parse \"path\" parameter for fifo output "
 179                       "at line %i\n", blockParam->line);
 180         }
 181
 182         fd = newFifoData();
 183         fd->path = path;
 184         audioOutput->data = fd;
 185
 186         if (openFifo(fd) < 0) {
 187                 freeFifoData(fd);
 188                 return -1;
 189         }
 190
 191         return 0;
 192 }
 193
 194 static void fifo_finishDriver(AudioOutput *audioOutput)
 195 {
 196         FifoData *fd = (FifoData *)audioOutput->data;
 197
 198         closeFifo(fd);
 199         freeFifoData(fd);
 200 }
 201
 202 static int fifo_openDevice(AudioOutput *audioOutput)
 203 {
 204         FifoData *fd = (FifoData *)audioOutput->data;
 205
 206         if (fd->timer)
 207                 timer_free(fd->timer);
 208
 209         fd->timer = timer_new(&audioOutput->outAudioFormat);
 210
 211         audioOutput->open = 1;
 212
 213         return 0;
 214 }
 215
 216 static void fifo_closeDevice(AudioOutput *audioOutput)
 217 {
 218         FifoData *fd = (FifoData *)audioOutput->data;
 219
 220         if (fd->timer) {
 221                 timer_free(fd->timer);
 222                 fd->timer = NULL;
 223         }
 224
 225         audioOutput->open = 0;
 226 }
 227
 228 static void fifo_dropBufferedAudio(AudioOutput *audioOutput)
 229 {
 230         FifoData *fd = (FifoData *)audioOutput->data;
 231         char buf[FIFO_BUFFER_SIZE];
 232         int bytes = 1;
 233
 234         timer_reset(fd->timer);
 235
 236         while (bytes > 0 && errno != EINTR)
 237                 bytes = read(fd->input, buf, FIFO_BUFFER_SIZE);
 238
 239         if (bytes < 0 && errno != EAGAIN) {
 240                 WARNING("Flush of FIFO \"%s\" failed: %s\n",
 241                         fd->path, strerror(errno));
 242         }
 243 }
 244
 245 static int fifo_playAudio(AudioOutput *audioOutput, char *playChunk, int size)
 246 {
 247         FifoData *fd = (FifoData *)audioOutput->data;
 248         int offset = 0;
 249         int bytes;
 250
 251         if (!fd->timer->started)
 252                 timer_start(fd->timer);
 253         else
 254                 timer_sync(fd->timer);
 255
 256         timer_add(fd->timer, size);
 257
 258         while (size) {
 259                 bytes = write(fd->output, playChunk + offset, size);
 260                 if (bytes < 0) {
 261                         switch (errno) {
 262                         case EAGAIN:
 263                                 /* The pipe is full, so empty it */
 264                                 fifo_dropBufferedAudio(audioOutput);
 265                                 continue;
 266                         case EINTR:
 267                                 continue;
 268                         }
 269
 270                         ERROR("Closing FIFO output \"%s\" due to write error: "
 271                               "%s\n", fd->path, strerror(errno));
 272                         fifo_closeDevice(audioOutput);
 273                         return -1;
 274                 }
 275
 276                 size -= bytes;
 277                 offset += bytes;
 278         }
 279
 280         return 0;
 281 }
 282
 283 AudioOutputPlugin fifoPlugin = {
 284         "fifo",
 285         NULL, /* testDefaultDeviceFunc */
 286         fifo_initDriver,
 287         fifo_finishDriver,
 288         fifo_openDevice,
 289         fifo_playAudio,
 290         fifo_dropBufferedAudio,
 291         fifo_closeDevice,
 292         NULL, /* sendMetadataFunc */
 293 };
 294
 295 #else /* HAVE_FIFO */
 296
 297 DISABLED_AUDIO_OUTPUT_PLUGIN(fifoPlugin)
 298
 299 #endif /* !HAVE_FIFO */