pipe output now handles SIGPIPE gracefully, closes file handle, re-op…

…ens file when another reader appears

hairtunes.c

@@ -36,6 +36,7 @@
 #include <openssl/aes.h>
 #include <math.h>
 #include <sys/stat.h>
+#include <sys/signal.h>
 #include <fcntl.h>
 #include <ao/ao.h>
 
@@ -67,7 +68,11 @@ int dataport = 0, controlport = 0, timingport = 0;
 int fmtp[32];
 int sampling_rate;
 int frame_size;
+
+// FIFO name and file handle
 char *pipename = 0;
+int pipe_handle = -1;
+
 #define FRAME_BYTES (4*frame_size)
 // maximal resampling shift - conservative
 #define OUTFRAME_BYTES (4*(frame_size+3))
@@ -182,9 +187,9 @@ int main(int argc, char **argv) {
  if (!strcasecmp(arg, "host")) {
  rtphost = *++argv;
  } else
- if (!strcasecmp(arg, "pipe")) {
- pipename = *++argv;
- }
+ if (!strcasecmp(arg, "pipe")) {
+ pipename = *++argv;
+ }
 #ifdef FANCY_RESAMPLING
  else
  if (!strcasecmp(arg, "resamp")) {
@@ -441,14 +446,14 @@ int init_rtp(void) {
  if(sock < 0)
  sock = socket(type, SOCK_DGRAM, IPPROTO_UDP);
 #ifdef AF_INET6
-  if(sock==-1 && type == AF_INET6) {
-  // try fallback to IPv4
-  type = AF_INET;
-  si_p = (struct sockaddr*)&si;
-  si_len = sizeof(si);
-  sin_port = &si.sin_port;
-  continue;
-  }
+  if(sock==-1 && type == AF_INET6) {
+  // try fallback to IPv4
+  type = AF_INET;
+  si_p = (struct sockaddr*)&si;
+  si_len = sizeof(si);
+  sin_port = &si.sin_port;
+  continue;
+  }
 #endif
  if (sock==-1)
  die("Can't create data socket!");
@@ -654,21 +659,12 @@ int stuff_buffer(double playback_rate, short *inptr, short *outptr) {
 
 void *audio_thread_func(void *arg) {
  ao_device* dev = arg;
- int fd = -1; // file handle for named pipe
  int play_samples;
 
  signed short buf_fill __attribute__((unused));
  signed short *inbuf, *outbuf;
  outbuf = malloc(OUTFRAME_BYTES);
 
- if (pipename) {
- fd = open(pipename, O_WRONLY);
- if (fd == -1) {
- printf( "Pipe open failure: %s\n", pipename );
- exit(1);
- }
- }
-
 #ifdef FANCY_RESAMPLING
  float *frame, *outframe;
  SRC_DATA srcdat;
@@ -692,7 +688,7 @@ void *audio_thread_func(void *arg) {
 
 #ifdef FANCY_RESAMPLING
  if (fancy_resampling) {
-  int i;
+  int i;
  for (i=0; i<2*FRAME_BYTES; i++) {
  frame[i] = (float)inbuf[i] / 32768.0;
  frame[i] *= volume;
@@ -707,25 +703,38 @@ void *audio_thread_func(void *arg) {
 
  play_samples = stuff_buffer(bf_playback_rate, inbuf, outbuf);
 
- if (pipename) {
- int ret = write(fd, outbuf, play_samples*4);
- if (!ret) {
- printf( "Pipe write error" );
- exit(1);
- }
- } else {
- ao_play(dev, (char *)outbuf, play_samples*4);
- }
+ if (pipename) {
+ if (pipe_handle == -1) {
+ // attempt to open pipe, don't block
+ pipe_handle = open(pipename, O_WRONLY | O_NDELAY);
+ }
+
+ // only write if pipe open (there's a reader)
+ if (pipe_handle != -1) {
+ if (write(pipe_handle, outbuf, play_samples*4) == -1) {
+ // write failed - do anything here?
+ // SIGPIPE is handled elsewhere...
+ }
+ }
+ } else {
+ ao_play(dev, (char *)outbuf, play_samples*4);
+ }
  }
 
  return 0;
 }
 
 #define NUM_CHANNELS 2
 
-void* init_pipe(char* pipe) {
- mknod(pipe, S_IFIFO | 0644, 0);
- return NULL;
+void handle_broken_fifo() {
+ close(pipe_handle);
+ pipe_handle = -1;
+}
+
+void init_pipe(char* pipe) {
+ // make the FIFO and catch the broken pipe signal
+ mknod(pipe, S_IFIFO | 0644, 0);
+ signal(SIGPIPE, handle_broken_fifo);
 }
 
 void* init_ao() {
@@ -747,11 +756,11 @@ void* init_ao() {
 int init_output(void) {
  void* arg = 0;
 
- if (pipename) {
- arg = init_pipe(pipename);
- } else {
- arg = init_ao();
- }
+ if (pipename) {
+  init_pipe(pipename);
+ } else {
+ arg = init_ao();
+ }
 
 #ifdef FANCY_RESAMPLING
  if (fancy_resampling)