mpd/src/output/fifo_plugin.c

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/* the Music Player Daemon (MPD)
* Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
* 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 "../output_api.h"
#include "../log.h"
#include "../utils.h"
#include "../timer.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define FIFO_BUFFER_SIZE 65536 /* pipe capacity on Linux >= 2.6.11 */
typedef struct _FifoData {
char *path;
int input;
int output;
int created;
Timer *timer;
} FifoData;
static FifoData *newFifoData(void)
{
FifoData *ret;
ret = xmalloc(sizeof(FifoData));
ret->path = NULL;
ret->input = -1;
ret->output = -1;
ret->created = 0;
ret->timer = NULL;
return ret;
}
static void freeFifoData(FifoData *fd)
{
if (fd->path)
free(fd->path);
if (fd->timer)
timer_free(fd->timer);
free(fd);
}
static void removeFifo(FifoData *fd)
{
DEBUG("Removing FIFO \"%s\"\n", fd->path);
if (unlink(fd->path) < 0) {
ERROR("Could not remove FIFO \"%s\": %s\n",
fd->path, strerror(errno));
return;
}
fd->created = 0;
}
static void closeFifo(FifoData *fd)
{
struct stat st;
if (fd->input >= 0) {
close(fd->input);
fd->input = -1;
}
if (fd->output >= 0) {
close(fd->output);
fd->output = -1;
}
if (fd->created && (stat(fd->path, &st) == 0))
removeFifo(fd);
}
static int makeFifo(FifoData *fd)
{
if (mkfifo(fd->path, 0666) < 0) {
ERROR("Couldn't create FIFO \"%s\": %s\n",
fd->path, strerror(errno));
return -1;
}
fd->created = 1;
return 0;
}
static int checkFifo(FifoData *fd)
{
struct stat st;
if (stat(fd->path, &st) < 0) {
if (errno == ENOENT) {
/* Path doesn't exist */
return makeFifo(fd);
}
ERROR("Failed to stat FIFO \"%s\": %s\n",
fd->path, strerror(errno));
return -1;
}
if (!S_ISFIFO(st.st_mode)) {
ERROR("\"%s\" already exists, but is not a FIFO\n", fd->path);
return -1;
}
return 0;
}
static int openFifo(FifoData *fd)
{
if (checkFifo(fd) < 0)
return -1;
fd->input = open(fd->path, O_RDONLY|O_NONBLOCK);
if (fd->input < 0) {
ERROR("Could not open FIFO \"%s\" for reading: %s\n",
fd->path, strerror(errno));
closeFifo(fd);
return -1;
}
fd->output = open(fd->path, O_WRONLY|O_NONBLOCK);
if (fd->output < 0) {
ERROR("Could not open FIFO \"%s\" for writing: %s\n",
fd->path, strerror(errno));
closeFifo(fd);
return -1;
}
return 0;
}
static void *fifo_initDriver(mpd_unused struct audio_output *ao,
mpd_unused const struct audio_format *audio_format,
ConfigParam *param)
{
FifoData *fd;
BlockParam *blockParam;
char *path;
blockParam = getBlockParam(param, "path");
if (!blockParam) {
FATAL("No \"path\" parameter specified for fifo output "
"defined at line %i\n", param->line);
}
path = parsePath(blockParam->value);
if (!path) {
FATAL("Could not parse \"path\" parameter for fifo output "
"at line %i\n", blockParam->line);
}
fd = newFifoData();
fd->path = path;
if (openFifo(fd) < 0) {
freeFifoData(fd);
return NULL;
}
return fd;
}
static void fifo_finishDriver(void *data)
{
FifoData *fd = (FifoData *)data;
closeFifo(fd);
freeFifoData(fd);
}
static int fifo_openDevice(void *data,
struct audio_format *audio_format)
{
FifoData *fd = (FifoData *)data;
if (fd->timer)
timer_free(fd->timer);
fd->timer = timer_new(audio_format);
return 0;
}
static void fifo_closeDevice(void *data)
{
FifoData *fd = (FifoData *)data;
if (fd->timer) {
timer_free(fd->timer);
fd->timer = NULL;
}
}
static void fifo_dropBufferedAudio(void *data)
{
FifoData *fd = (FifoData *)data;
char buf[FIFO_BUFFER_SIZE];
int bytes = 1;
timer_reset(fd->timer);
while (bytes > 0 && errno != EINTR)
bytes = read(fd->input, buf, FIFO_BUFFER_SIZE);
if (bytes < 0 && errno != EAGAIN) {
WARNING("Flush of FIFO \"%s\" failed: %s\n",
fd->path, strerror(errno));
}
}
static int fifo_playAudio(void *data,
const char *playChunk, size_t size)
{
FifoData *fd = (FifoData *)data;
size_t offset = 0;
ssize_t bytes;
if (!fd->timer->started)
timer_start(fd->timer);
else
timer_sync(fd->timer);
timer_add(fd->timer, size);
while (size) {
bytes = write(fd->output, playChunk + offset, size);
if (bytes < 0) {
switch (errno) {
case EAGAIN:
/* The pipe is full, so empty it */
fifo_dropBufferedAudio(fd);
continue;
case EINTR:
continue;
}
ERROR("Closing FIFO output \"%s\" due to write error: "
"%s\n", fd->path, strerror(errno));
fifo_closeDevice(fd);
return -1;
}
size -= bytes;
offset += bytes;
}
return 0;
}
const struct audio_output_plugin fifoPlugin = {
.name = "fifo",
.init = fifo_initDriver,
.finish = fifo_finishDriver,
.open = fifo_openDevice,
.play = fifo_playAudio,
.cancel = fifo_dropBufferedAudio,
.close = fifo_closeDevice,
};