#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <linux/limits.h>
#include <stdio.h>
#include <string.h>
#include <sys/xattr.h>
#include <unistd.h>

static const char foo[] = "foo\n";

int main(int argc, char **argv) {
	char path[PATH_MAX];
	char *dir;
	int err;
	int fd;

	if (argc < 2) {
		fprintf(stderr, "You have to pass file as argument\n");
		return -ENOENT;
	}

	dir = strdup(argv[1]);
	if (!dir) {
		return -ENOMEM;
	}
	dir = dirname(dir);
	fd = open(dir, O_TMPFILE | O_RDWR);
	if (fd < 0) {
		err = -errno;
		fprintf(stderr, "Failed to open O_TMPFILE: %d\n", err);
		return err;
	}

#if 0
	if (argc >= 4) {
		if (fsetxattr(fd, argv[2], argv[3], strlen(argv[3]), 0) != 0) {
			err = -errno;
			fprintf(stderr, "Failed to fsetxattr(): %d\n", err);
			return err;
		}
		printf("Wrote xattr \"%s\" value \"%s\"\n", argv[2], argv[3]);
	}
#endif

	if (write(fd, foo, sizeof(foo)) != sizeof(foo)) {
		err = -errno;
		fprintf(stderr, "Failed to write(): %d\n", err);
		return err;
	}

	if (fsync(fd) < 0) {
		err = -errno;
		fprintf(stderr, "Failed to fsync(): %d\n", err);
		return err;
	}

#if 1
	if (argc >= 4) {
		if (fsetxattr(fd, argv[2], argv[3], strlen(argv[3]), 0) != 0) {
			err = -errno;
			fprintf(stderr, "Failed to fsetxattr(): %d\n", err);
			return err;
		}
		printf("Wrote xattr \"%s\" value \"%s\"\n", argv[2], argv[3]);
	}
#endif

	snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
	if (linkat(-1, path, AT_FDCWD, argv[1], AT_SYMLINK_FOLLOW) != 0) {
		err = -errno;
		fprintf(stderr, "Failed to linkat(): %d\n", err);
		return err;
	}

	printf("Success!\n");

	return 0;
}