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/*
*
* Stream PIPE output - Stream a program to a FIFO for postprocessing
*
* One of the problems i could imaging is that for a program which does not get
* and traffic e.g. TS Packets we'll never discover that the reader closed the pipe
* as we never issue a write. This shouldnt be a problem but you are warned. Flo 2007-04-19
*
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "output.h"
#include "simplebuffer.h"
#include "getstream.h"
#define PIPE_BUFFER 32768
#define PIPE_INTERVAL 5
#define PIPE_MAXEAGAIN 10
static int output_pipe_tryopen(struct output_s *o) {
o->pipe.fd=open(o->pipe.filename, O_NONBLOCK|O_WRONLY);
if (o->pipe.fd >= 0) {
logwrite(LOG_INFO, "stream_pipe: starting to write to %s - got reader", o->pipe.filename);
o->receiver++;
sb_zap(o->buffer);
return 1;
}
if (errno == ENXIO)
return 0;
logwrite(LOG_ERROR, "stream_pipe: failed to open fifo %s", o->pipe.filename);
return 0;
}
static void output_pipe_open_event(int fd, short event, void *arg);
static void output_pipe_event_init(struct output_s *o) {
struct timeval tv;
tv.tv_usec=0;
tv.tv_sec=PIPE_INTERVAL;
evtimer_set(&o->pipe.event, output_pipe_open_event, o);
evtimer_add(&o->pipe.event, &tv);
}
static void output_pipe_open_event(int fd, short event, void *arg) {
struct output_s *o=arg;
/* Try opening - if it fails - retry */
if (!output_pipe_tryopen(o))
output_pipe_event_init(o);
}
static void output_pipe_close(struct output_s *o) {
o->receiver--;
close(o->pipe.fd);
logwrite(LOG_INFO, "stream_pipe: closing %s - reader exited", o->pipe.filename);
/* PIPE is closed - try opening on regular interval */
output_pipe_event_init(o);
}
int output_init_pipe(struct output_s *o) {
struct stat st;
if (!lstat(o->pipe.filename, &st)) {
if (!S_ISFIFO(st.st_mode)) {
logwrite(LOG_ERROR, "stream_pipe: %s exists and is not a pipe", o->pipe.filename);
return 0;
}
} else {
/* if lstat fails we possibly have no fifo */
/* FIXME we need to check errno for non existant */
if (mknod(o->pipe.filename, S_IFIFO|0700, 0)) {
logwrite(LOG_ERROR, "stream_pipe: failed to create fifo %s", o->pipe.filename);
return 0;
}
}
o->buffer=sb_init(PIPE_BUFFER, 1, 0);
if (!o->buffer)
return 0;
signal(SIGPIPE, SIG_IGN);
output_pipe_event_init(o);
return 1;
}
void output_send_pipe(struct output_s *o, uint8_t *tsp) {
int len;
if (sb_free_atoms(o->buffer) < TS_PACKET_SIZE) {
logwrite(LOG_ERROR, "stream_pipe: buffer overflow - dropping");
output_pipe_close(o);
return;
}
sb_add_atoms(o->buffer, tsp, TS_PACKET_SIZE);
len=write(o->pipe.fd, sb_bufptr(o->buffer), sb_buflen(o->buffer));
/*
* We zap the buffer if we succeeded writing or not - there is no point
* in keeping the data - If the reader aint fast enough there is no point
* in buffering.
*/
if (len < 0) {
if (errno == EAGAIN) {
return;
}
logwrite(LOG_ERROR, "stream_pipe: write returned %d / %s", errno, strerror(errno));
output_pipe_close(o);
return;
}
sb_drop_atoms(o->buffer, len);
/* FIXME - We might want to do more graceful here. We tried
* writing multiple TS packets to the FIFO and it failed. We
* now discard ALL packets in our buffer so we might loose some.
* A more graceful way would be to retry writing - For this we
* might need a different buffer design e.g. a ringbuffr
*
* Use libevent to get a callback when the reader is ready ?
*
*/
}
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