logfilec.c

understanding unix/linux programming source code(bruce molay)

/**********************************************************************
 * logfilec.c - logfile client - send messages to the logfile server
 *              usage: logfilec "a message here"
 */

#include	<stdio.h>
#include	<sys/types.h>
#include	<sys/socket.h>
#include	<sys/un.h>

#define	SOCKET	"/tmp/logfilesock"
#define	oops(m,x) { perror(m); exit(x); }

main(int ac, char *av[])
{
	int	           sock;
	struct sockaddr_un addr;
	socklen_t          addrlen;
	char	           sockname[] = SOCKET ;
	char               *msg = av[1];

	if ( ac != 2 ){
		fprintf(stderr,"usage: logfilec 'message'\n");
		exit(1);
	}
	sock = socket(PF_UNIX, SOCK_DGRAM, 0);
	if ( sock == -1 )
		oops("socket",2);

	addr.sun_family = AF_UNIX;
	strcpy(addr.sun_path, sockname);
	addrlen = strlen(sockname) + sizeof(addr.sun_family) ;

	if ( sendto(sock,msg, strlen(msg), 0, 
				(struct sockaddr *)&addr, addrlen) == -1 )
		oops("sendto",3);
}