cliconn.c

UNIX环境高级编程书的源代码

#include "apue.h"
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>

#define	CLI_PATH	"/var/tmp/"		/* +5 for pid = 14 chars */
#define	CLI_PERM	S_IRWXU			/* rwx for user only */

/*
 * Create a client endpoint and connect to a server.
 * Returns fd if all OK, <0 on error.
 */
int
cli_conn(const char *name)
{
	int					fd, len, err, rval;
	struct sockaddr_un	un;

	/* create a UNIX domain stream socket */
	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
		return(-1);

	/* fill socket address structure with our address */
	memset(&un, 0, sizeof(un));
	un.sun_family = AF_UNIX;
	sprintf(un.sun_path, "%s%05d", CLI_PATH, getpid());
	len = offsetof(struct sockaddr_un, sun_path) + strlen(un.sun_path);

	unlink(un.sun_path);		/* in case it already exists */
	if (bind(fd, (struct sockaddr *)&un, len) < 0) {
		rval = -2;
		goto errout;
	}
	if (chmod(un.sun_path, CLI_PERM) < 0) {
		rval = -3;
		goto errout;
	}

	/* fill socket address structure with server's address */
	memset(&un, 0, sizeof(un));
	un.sun_family = AF_UNIX;
	strcpy(un.sun_path, name);
	len = offsetof(struct sockaddr_un, sun_path) + strlen(name);
	if (connect(fd, (struct sockaddr *)&un, len) < 0) {
		rval = -4;
		goto errout;
	}
	return(fd);

errout:
	err = errno;
	close(fd);
	errno = err;
	return(rval);
}