#include <stdio.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>

#define DEF_MODE	022

int error(char *s, char *t, char *u)
{
	write(2, s, strlen(s) * sizeof(char));
	write(2, t, strlen(t) * sizeof(char));
	write(2, u, strlen(u) * sizeof(char));
}

int main(int argc, char *argv[])
{
	char *filename;		/* name of file to create */
	int fd;			/* file descriptor */
	mode_t umsk, mode;
	char *ep;

	/* first is the file name */
	if (argc > 1)	filename = argv[1];

	/* next comes the desired protection mode */
	if (argc > 2){
		if (strcmp(argv[2], "-") == 0)
			mode = DEF_MODE;
		else{
			mode = strtol(argv[2], &ep, 8);
			if (*ep != '\0' || mode < 0 || mode > 0777){
				error("Bad mode: '", argv[2], "'\n");
				return(1);
			}
		}
	}

	/* next comes the desired umask */
	if (argc > 3){
		if (strcmp(argv[2], "-") != 0){
			umsk = strtol(argv[3], &ep, 8);
			if (*ep != '\0' || umsk < 0 || umsk > 0777){
				error("Bad umask: '", argv[3], "'\n");
				return(1);
			}
			umask(umsk);
		}
	}

	/* if there's anything else, error */
	if (argc > 4){
		error("Usage: ", argv[0], " filename [-|mode] [umask]\n");
		return(1);
	}

	printf("mode = %o, umask = %o\n", mode, umsk);
	if ((fd = open(argv[1], O_WRONLY|O_CREAT, mode)) < 0){
		error(argv[1], ":", " ");
		error(strerror(errno), "\n", "");
	}

	return(0);
}