/* soundd.d - Accept network clients for live audio source */

/*
 *  Copyright (C) 1995-2005 Jeffrey Chilton
 *
 *  Permission is granted to anyone to make or distribute copies of
 *  this program, in any medium, provided that the copyright notice
 *  and permission notice are preserved, and that the distributor
 *  grants the recipient permission for further redistribution as
 *  permitted by this notice.
 *  
 *  Author's E-mail address:  jwc@chilton.com
 *  
 */

#include <sys/errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioccom.h>
#include <netinet/in.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <syslog.h>

#define AUDIO_PORT 8480
#define AUDIO_DEVICE "/dev/sound"

#define TRUE 1

#define BITE_SIZE 16000
#define N_BITE_BUFFERS 20

char Bite[N_BITE_BUFFERS][BITE_SIZE];

unsigned long CurrentBite;
unsigned long ClientBite[FD_SETSIZE];

#define N_LOOK_BACK 6

int Listen_fd;
int Source_fd;

fd_set Client_fds;

int Debug = 0;
int Max_fd = 0;

void doggy(int sigraised)
{
    syslog(LOG_NOTICE, "watchdog signal caught\n");
}

main()
{
    register int i, j;
    struct sockaddr_in server;
    fd_set r_fds, w_fds;
    struct timeval to;
    int data_fd;
    int buffer;
    int rc;

    openlog("soundd", LOG_PID, LOG_USER);

    signal(SIGPIPE, SIG_IGN);
    signal(SIGALRM, doggy);

    /* Start listening for clients */

    Listen_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (Listen_fd < 0)
    {
	syslog(LOG_NOTICE, "error opening listen socket\n");
	exit(1);
    }

    /* Name socket with my made-up server number */

    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons(AUDIO_PORT);

    if (bind(Listen_fd, (struct sockaddr *)&server, sizeof(server)))
    {
	syslog(LOG_NOTICE, "error binding listen socket\n");
	exit(1);
    }

    syslog(LOG_NOTICE, "accepting connections\n");

    rc = listen(Listen_fd, 5);
    if (rc < 0)
    {
	syslog(LOG_NOTICE, "error listening\n");
	exit(1);
    }

RESTART:

    /* Open the sound device */

    Source_fd = open(AUDIO_DEVICE, O_RDONLY, (mode_t )0);
    if (Source_fd < 0)
    {
	syslog(LOG_NOTICE, "error opening sound device\n");
	exit(1);
    }

    /* Prime the pump */

    rc = read(Source_fd, Bite[0], BITE_SIZE);
    if (rc < 0)
    {
	syslog(LOG_NOTICE, "error reading sound device\n");
	exit(1);
    }

    /* Main service loop */

    CurrentBite = 0;

    to.tv_sec = 100;
    to.tv_usec = 0;

    while (TRUE)
    {
	alarm(5);

        /* Build FD sets for select() call */

	FD_ZERO(&r_fds);
	FD_SET(Listen_fd, &r_fds);
	FD_SET(Source_fd, &r_fds);

	FD_ZERO(&w_fds);
	for (i = 0; i < FD_SETSIZE; i++)
	{
	    if (FD_ISSET(i, &Client_fds) && ClientBite[i] < CurrentBite)
	    {
		FD_SET(i, &w_fds);
	    }
	}

	/* Wait for whatever... */

	rc = select(FD_SETSIZE, &r_fds, &w_fds, 0, &to);
	if (rc < 0)
	{
	    syslog(LOG_NOTICE, "select fails\n");
	    exit(1);
	}

	/* Check for sound availiable */

	if (FD_ISSET(Source_fd, &r_fds))
	{
	    if (CurrentBite % 7200 == 0)
	    {
		syslog(LOG_NOTICE, "Current bite is #%d\n", CurrentBite);
	    }
	    buffer = CurrentBite++ % N_BITE_BUFFERS;
	    rc = read(Source_fd, Bite[buffer], BITE_SIZE);
	    if (rc < 0)
	    {
		syslog(LOG_NOTICE, "Error reading sound device (%d): %s\n", rc, strerror(errno));
		syslog(LOG_NOTICE, "Current bite %d buffer %d\n", CurrentBite, buffer);
		syslog(LOG_NOTICE, "Restarting...\n");
		close(Source_fd);
		goto RESTART;
	    }
	    if (rc < BITE_SIZE)
	    {
		syslog(LOG_NOTICE, "short read from sound device (%d)\n", rc);
	    }

	}
	    
	/* Check for writable clients */

	for (i = 0; i < FD_SETSIZE; i++)
	{
	    if (FD_ISSET(i, &w_fds))
	    {
		buffer = ClientBite[i] % N_BITE_BUFFERS;
		rc = write(i, Bite[buffer], BITE_SIZE);
		if (rc < 0)
		{
		    close(i);
		    if (Debug)
		    {
			syslog(LOG_NOTICE, "closed #%d at %d\n", i, CurrentBite);
		    }
		    FD_CLR(i, &Client_fds);
		}
		else if (rc < BITE_SIZE)
		{
		    syslog(LOG_NOTICE, "short write to #%d (%d)\n", i, rc);
		}
	        ClientBite[i]++;
	    }
	}

	/* Check for new clients calling */

	if (CurrentBite > N_LOOK_BACK && FD_ISSET(Listen_fd, &r_fds))
	{
	    data_fd = accept(Listen_fd, (struct sockaddr *)0, (int *)0);
	    if (data_fd == -1)
	    {
		syslog(LOG_NOTICE, "accept fails\n");
		continue;
	    }
	    FD_SET(data_fd, &Client_fds);
	    ClientBite[data_fd] = CurrentBite - N_LOOK_BACK;
	    if (Debug || data_fd > Max_fd)
	    {
		syslog(LOG_NOTICE, "new client on #%d at %d\n", data_fd, CurrentBite);
		Max_fd = data_fd > Max_fd ? data_fd : Max_fd;
	    }
	}

    }
}