unpv13e/unixdomain/myopen.c

#include	"unp.h"

int
my_open(const char *pathname, int mode)
{
	int			fd, sockfd[2], status;
	pid_t		childpid;
	char		c, argsockfd[10], argmode[10];

	Socketpair(AF_LOCAL, SOCK_STREAM, 0, sockfd);

	if ( (childpid = Fork()) == 0) {		/* child process */
		Close(sockfd[0]);
		snprintf(argsockfd, sizeof(argsockfd), "%d", sockfd[1]);
		snprintf(argmode, sizeof(argmode), "%d", mode);
		execl("./openfile", "openfile", argsockfd, pathname, argmode,
			  (char *) NULL);
		err_sys("execl error");
	}

	/* parent process - wait for the child to terminate */
	Close(sockfd[1]);			/* close the end we don't use */

	Waitpid(childpid, &status, 0);
	if (WIFEXITED(status) == 0)
		err_quit("child did not terminate");
	if ( (status = WEXITSTATUS(status)) == 0)
		Read_fd(sockfd[0], &c, 1, &fd);
	else {
		errno = status;		/* set errno value from child's status */
		fd = -1;
	}

	Close(sockfd[0]);
	return(fd);
}