/* SPDX-License-Identifier: MIT */

/*

 * Simple app that demonstrates how to setup an io_uring interface,

 * submit and complete IO against it, and then tear it down.

 *

 * gcc -Wall -O2 -D_GNU_SOURCE -o io_uring-test io_uring-test.c -luring

 */

#include <stdio.h>

#include <fcntl.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include "liburing.h"

#define QD	4

int main(int argc, char *argv[])

{

	struct io_uring ring;

	int i, fd, ret, pending, done;

	struct io_uring_sqe *sqe;

	struct io_uring_cqe *cqe;

	struct iovec *iovecs;

	off_t offset;

	void *buf;

	if (argc < 2) {

		printf("%s: file\n", argv[0]);

		return 1;

	}

	ret = io_uring_queue_init(QD, &ring, 0);

	if (ret < 0) {

		fprintf(stderr, "queue_init: %s\n", strerror(-ret));

		return 1;

	}

	fd = open(argv[1], O_RDONLY | O_DIRECT);

	if (fd < 0) {

		perror("open");

		return 1;

	}

	iovecs = calloc(QD, sizeof(struct iovec));

	for (i = 0; i < QD; i++) {

		if (posix_memalign(&buf, 4096, 4096))

			return 1;

		iovecs[i].iov_base = buf;

		iovecs[i].iov_len = 4096;

	}

	offset = 0;

	i = 0;

	do {

		sqe = io_uring_get_sqe(&ring);

		if (!sqe)

			break;

		io_uring_prep_readv(sqe, fd, &iovecs[i], 1, offset);

		offset += iovecs[i].iov_len;

		i++;

	} while (1);

	ret = io_uring_submit(&ring);

	if (ret < 0) {

		fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));

		return 1;

	}

	done = 0;

	pending = ret;

	for (i = 0; i < pending; i++) {

		ret = io_uring_wait_cqe(&ring, &cqe);

		if (ret < 0) {

			fprintf(stderr, "io_uring_wait_cqe: %s\n", strerror(-ret));

			return 1;

		}

		done++;

		ret = 0;

		if (cqe->res != 4096) {

			fprintf(stderr, "ret=%d, wanted 4096\n", cqe->res);

			ret = 1;

		}

		io_uring_cqe_seen(&ring, cqe);

		if (ret)

			break;

	}

	printf("Submitted=%d, completed=%d\n", pending, done);

	close(fd);

	io_uring_queue_exit(&ring);

	return 0;

}