/* dispatcher.c --
 * 
 * This is a sample program that you can customize to create your own syslog
 * event handler. It will be started by syslog via the dispatcher option on
 * command line. This program can be built as follows:
 *
 * gcc dispatcher.c -o dispatcher
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <locale.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/select.h>
#include <sys/un.h>

#include "sysklogd-dispatch.h"


/* Local data */
static volatile int signaled = 0;
static int pipe_fd;
static struct sockaddr_un my_addr;
static int fd;

/* Local functions */
static int event_loop(void);

/* SIGTERM handler */
static void term_handler( int sig )
{
	signaled = 1;
}


/*
 * main is started by sysklogd. See dispatcher in man sysklogd.
 */
int main(int argc, char *argv[])
{
	struct sigaction sa;
	struct stat stat_buf;

	setlocale (LC_ALL, "");
	fprintf(stderr, "starting dispatcher...\n");

#ifndef DEBUG
	/* Make sure we are root */
	if (getuid() != 0) {
		fprintf(stderr, "You must be root to run this program.");
		exit(1);
	}
#endif

	/* register sighandlers */
	sa.sa_flags = 0 ;
	sa.sa_handler = term_handler;
	sigemptyset( &sa.sa_mask ) ;
	sigaction( SIGTERM, &sa, NULL );
     /*	sa.sa_handler = term_handler;
	sigemptyset( &sa.sa_mask ) ;
	sigaction( SIGCHLD, &sa, NULL ); */
	sa.sa_handler = SIG_IGN;
	sigaction( SIGHUP, &sa, NULL );
	sigaction( SIGPIPE, &sa, NULL );
	(void)chdir("/");

	/* change over to pipe_fd */
	pipe_fd = dup(0);
	close(0);
	fcntl(pipe_fd, F_SETFD, FD_CLOEXEC);

	/* Setup server */
	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
		perror("socket()");
		exit(1);
	}
	fcntl(fd, F_SETFD, O_NONBLOCK);
	my_addr.sun_family=AF_UNIX;  
  	strncpy(my_addr.sun_path, "/tmp/dispatcher.sock", sizeof(my_addr.sun_path));
	unlink(my_addr.sun_path); /* not necessary */
	if (bind(fd, (struct sockaddr *) &my_addr, sizeof(my_addr)) == -1) {
		perror("bind()");
		exit(1);
	}
	stat(my_addr.sun_path, &stat_buf);
	chmod(my_addr.sun_path, stat_buf.st_mode | S_IWOTH);
	if (listen(fd, 1) == -1) {
		perror("listen()");
		exit(1);
	}

	/* Start the program */
	return event_loop();
}

static int event_loop(void)
{
	void* data;
	struct iovec vec[2];
	struct sysklogd_dispatcher_header hdr;
	pid_t pid;
	static socklen_t addrlen;
	int new_fd = -1;


	/* Allocate data structures */
	data = malloc(MAXLINE);
	if (data == NULL) {
		fprintf(stderr, "Cannot allocate buffer\n");
		return 1;
	}

	do {
		int rc;
		struct timeval tv;
		fd_set fdset;


		/* if there isn't anybody connected to server, try accept */
		if (new_fd == -1 ) {
			addrlen = sizeof(my_addr);
			if ((new_fd = accept( fd, (struct sockaddr *) &my_addr, &addrlen))==-1) {
				perror("accept()");
				exit(1);
			}
		}

		memset(data, 0, MAXLINE);
		memset(&hdr, 0, sizeof(hdr));

		tv.tv_sec = 1;
		tv.tv_usec = 0;
		FD_ZERO(&fdset);
		FD_SET(pipe_fd, &fdset);
		rc = select(pipe_fd+1, &fdset, NULL, NULL, &tv);
		if (rc == 0) 
			continue;
		 else if (rc == -1)
			break;

		/* Get header first. it is fixed size */
		vec[0].iov_base = (void*)&hdr;
		vec[0].iov_len = sizeof(hdr);
		rc = readv(pipe_fd, vec, 1);
		if (rc == 0 || rc == -1) {
			fprintf(stderr, "rc == %d(%s)\n", rc, strerror(errno));
			break;
		}

		/* Analyze header */
			/*nothing to do at the momemnt */

        	/* Next payload */
		vec[1].iov_base = data;
		vec[1].iov_len = MAXLINE; 
		rc = readv(pipe_fd, &vec[1], 1);
		if (rc == 0 || rc == -1) {
			fprintf(stderr, "rc == %d(%s)\n", rc, strerror(errno));
			break;
		}

		/* handle some events here. */
		if (new_fd != -1) {
			rc = write(new_fd, (char *)data, strlen(data));
			if (rc <= 0) {
				if (errno == EPIPE) {
					close(new_fd);
					new_fd=-1;
				} else {	
					perror("writev()");
					new_fd=-1;
				}
			}
		}		
/*
		if( strstr((char *)data, "oops") ) {
			pid = fork();
			if( !pid ) {
				execl("/usr/bin/zenity","/usr/bin/zenity","--warning",
				      "--text", (char *)data, NULL);
				fprintf(stderr, "exec() failed\n");
		        }
		}
*/
/*
		 fprintf(stderr,"type=%d, payload size=%d\n", 
			hdr.type, hdr.size);
		   fprintf(stderr,"data=\"%.*s\"\n", hdr.size,
			(char *)data); 
*/
	} while(!signaled);

	return 0;
}