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

int main(int argc, char *argv[])
{
	size_t len;
	int fd;
	void *ptr;

	if (argc != 3) {
		fprintf(stderr, "usage: %s <file> <mapsize>\n",
			argv[0]);
		return -1;
	}

	len = atoi(argv[2]);

	fd = open(argv[1], O_RDONLY);
	if (fd == -1) {
		fprintf(stderr, "open failed: %s\n", strerror(errno));
		return errno;
	}

	ptr = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0);
	if (ptr == MAP_FAILED) {
		fprintf(stderr, "mmap failed: %s\n", strerror(errno));
		return errno;
	}

	printf("mmap of %s with size %zd succeeded\n", argv[1], len);

	munmap(ptr, len); /* ignore any errors, we don't care */
	close(fd);
	return 0;
}