#define _ISOC99_SOURCE 1
#define _BSD_SOURCE 1


#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#define MAX_INT_SIZE_HALF(the_int) \
	((the_int)1 << ((CHAR_BIT) * \
		(sizeof(the_int)) - 1 - ((the_int)-1 < 1?1:0)))

#define MAX_INT_SIZE(the_int) \
	((MAX_INT_SIZE_HALF(the_int) - 1) + MAX_INT_SIZE_HALF(the_int))

int main(int argc, char *argv[])
{
	intmax_t size;
	off_t the_size;
	char *file;
	int fd;

	if (argc != 3) {
		fprintf(stderr, "Usage: %s <file> <size>\n", argv[0]);
		exit(EXIT_FAILURE);
	}

	file = argv[1];

	if (sscanf(argv[2], "%jd", &size) != 1
		|| size < 0 || size > (intmax_t)MAX_INT_SIZE(off_t)) {
		if (size < 0)
			fprintf(stderr, "Size has to be a positive integer.\n");
		else
			fprintf(stderr, "Size is too big. Maximum is: %jd.\n",
					(intmax_t)MAX_INT_SIZE(off_t));
		exit(EXIT_FAILURE);
	}

	the_size = (off_t) size;
	
	fd = open(file, O_RDWR | O_CREAT | O_EXCL, DEFFILEMODE);
	if (fd < 0) {
		perror("Error opening file");
		exit(EXIT_FAILURE);
	}

	if (ftruncate(fd, the_size) < 0) {
		perror("Error truncating file");
		close(fd);
		unlink(file);
		exit(EXIT_FAILURE);
	}

	close(fd);

	exit(EXIT_SUCCESS);
}