provide -B/-E for running shell commands on begin/end of playing

Implements functionality described by MaZderMind <[email protected]>
in issue mikebrady#201.

common.h

@@ -26,6 +26,7 @@ typedef struct {
  int buffer_start_fill;
  int daemonise;
  int mdns_internal;
+ char *cmd_start, *cmd_stop;
 } shairport_cfg;
 
 extern int debuglev;

player.c

@@ -36,6 +36,7 @@
 #include <sys/signal.h>
 #include <assert.h>
 #include <fcntl.h>
+#include <stdlib.h>
 
 #include "common.h"
 #include "player.h"
@@ -515,6 +516,11 @@ int player_play(stream_cfg *stream) {
 #endif
 
  please_stop = 0;
+ if (config.cmd_start && !fork()) {
+ if (system(config.cmd_start))
+ warn("exec of external start command failed\n");
+ exit(0);
+ }
  config.output->start(sampling_rate);
  pthread_create(&player_thread, NULL, player_thread_func, NULL);
 
@@ -525,6 +531,11 @@ void player_stop(void) {
  please_stop = 1;
  pthread_join(player_thread, NULL);
  config.output->stop();
+ if (config.cmd_stop && !fork()) {
+ if (system(config.cmd_stop))
+ warn("exec of external stop command failed\n");
+ exit(0);
+ }
  free_buffer();
  free_decoder();
 #ifdef FANCY_RESAMPLING

shairport.c

@@ -71,6 +71,9 @@ void usage(char *progname) {
  " This value is in frames; default %d\n"
  " -d fork (daemonise)\n"
  " The PID of the child process is written to stdout\n"
+ " -B command run a shell command when playback begins\n"
+ " -E command run a shell command when playback ends\n"
+ "\n"
  "Run %s -o <output> -h to find the available options for a specific output\n"
  "\n", config.buffer_start_fill, progname);
 
@@ -86,7 +89,7 @@ void usage(char *progname) {
 
 int parse_options(int argc, char **argv) {
  int opt;
- while ((opt = getopt(argc, argv, "+hdvp:a:o:b:")) > 0) {
+ while ((opt = getopt(argc, argv, "+hdvp:a:o:b:B:E:")) > 0) {
  switch (opt) {
  default:
  printf("Unknown argument -%c\n", optopt);
@@ -111,6 +114,12 @@ int parse_options(int argc, char **argv) {
  case 'b':
  config.buffer_start_fill = atoi(optarg);
  break;
+ case 'B':
+ config.cmd_start = optarg;
+ break;
+ case 'E':
+ config.cmd_stop = optarg;
+ break;
  }
  }
  return optind;