/*
* Fixup file descriptors so that all stdin and stdout of the application
* is piped to alt_stdout (for stdout) and alt_stdin (for stdin).
* Now we can watch and modify the datastream from and to the application.
* That allows us to insert keep-alive characters to keep socat happy!
*/
int comm_init( void)
{
int result;
int fds[ 2];
// keep a copy of the program's original fds for stdin and stdout
fd_stdin = fcntl( 0, F_DUPFD);
fd_stdout = fcntl( 1, F_DUPFD);
// Note on debug output: Because we're messing with stdout,
// all debug output for 'comm_init' is sent to stderr instead of stdout !
if (DEBUG_COMM && (debug_flags & DEBUG_COMM)) {
fprintf( stderr, "fd_stdin = %d, fd_stdout = %d\n", fd_stdin, fd_stdout);
}
// create the output pipe with all new fds
// replace application's stdout descriptor (1) by write side of output pipe
result = pipe2( fds, O_NONBLOCK);
if (result < 0) {
perror( "output pipe creation failed");
return -1;
}
close( 1);
result = fcntl( fds[ 1], F_DUPFD);
close( fds[ 1]);
fds[ 1] = result;
if (DEBUG_COMM && (debug_flags & DEBUG_COMM)) {
fprintf( stderr, "output pipe: output/read side fd = %d, input/write side fd = %d\n", fds[ 0], fds[ 1]);
}
alt_stdout = fds[ 0];
// create the input pipe with all new fds
// replace application's stdin descriptor (0) by read side of input pipe
close( 0);
result = pipe2( fds, 0);
if (result < 0) {
perror( "input pipe creation failed");
return -1;
}
if (DEBUG_COMM && (debug_flags & DEBUG_COMM)) {
fprintf( stderr, "input pipe: output/read side fd = %d, input/write side fd = %d\n", fds[ 0], fds[ 1]);
}
alt_stdin = fds[ 1];
if (DEBUG_COMM && (debug_flags & DEBUG_COMM)) {
fprintf( stderr, "alt_stdin = %d, alt_stdout = %d\n", alt_stdin, alt_stdout);
}
if (mendel_thread_create( "comm", &worker, NULL, &comm_thread, NULL) != 0) {
return -1;
}
struct sched_param param = {
.sched_priority = COMM_PRIO
};
pthread_setschedparam( worker, COMM_SCHED, ¶m);
return 0;
}
int limsw_init( void)
{
fdset = calloc( nr_limits, sizeof( struct pollfd));
if (mendel_thread_create( "limit_switches", &worker, NULL, &limsw_watcher, NULL) != 0) {
return -1;
}
struct sched_param param = {
.sched_priority = LIMSW_PRIO
};
pthread_setschedparam( worker, LIMSW_SCHED, ¶m);
return 0;
}
