/* SPDX-License-Identifier: MIT */

/*

 * Description: basic fadvise test

 */

#include <errno.h>

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <string.h>

#include <fcntl.h>

#include <sys/types.h>

#include <sys/time.h>

#include "liburing.h"

#define FILE_SIZE	(128 * 1024)

#define LOOPS		100

#define MIN_LOOPS	10

static unsigned long long utime_since(const struct timeval *s,

				      const struct timeval *e)

{

	long long sec, usec;

	sec = e->tv_sec - s->tv_sec;

	usec = (e->tv_usec - s->tv_usec);

	if (sec > 0 && usec < 0) {

		sec--;

		usec += 1000000;

	}

	sec *= 1000000;

	return sec + usec;

}

static unsigned long long utime_since_now(struct timeval *tv)

{

	struct timeval end;

	gettimeofday(&end, NULL);

	return utime_since(tv, &end;;

}

static int create_file(const char *file)

{

	ssize_t ret;

	char *buf;

	int fd;

	buf = malloc(FILE_SIZE);

	memset(buf, 0xaa, FILE_SIZE);

	fd = open(file, O_WRONLY | O_CREAT, 0644);

	if (fd < 0) {

		perror("open file");

		return 1;

	}

	ret = write(fd, buf, FILE_SIZE);

	fsync(fd);

	close(fd);

	return ret != FILE_SIZE;

}

static int do_fadvise(struct io_uring *ring, int fd, off_t offset, off_t len,

		      int advice)

{

	struct io_uring_sqe *sqe;

	struct io_uring_cqe *cqe;

	int ret;

	sqe = io_uring_get_sqe(ring);

	if (!sqe) {

		fprintf(stderr, "failed to get sqe\n");

		return 1;

	}

	io_uring_prep_fadvise(sqe, fd, offset, len, advice);

	sqe->user_data = advice;

	ret = io_uring_submit_and_wait(ring, 1);

	if (ret != 1) {

		fprintf(stderr, "submit: %d\n", ret);

		return 1;

	}

	ret = io_uring_wait_cqe(ring, &cqe);

	if (ret) {

		fprintf(stderr, "wait: %d\n", ret);

		return 1;

	}

	ret = cqe->res;

	if (ret == -EINVAL || ret == -EBADF) {

		fprintf(stdout, "Fadvise not supported, skipping\n");

		unlink(".fadvise.tmp");

		exit(0);

	} else if (ret) {

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

	}

	io_uring_cqe_seen(ring, cqe);

	return ret;

}

static long do_read(int fd, char *buf)

{

	struct timeval tv;

	int ret;

	long t;

	ret = lseek(fd, 0, SEEK_SET);

	if (ret) {

		perror("lseek");

		return -1;

	}

	gettimeofday(&tv, NULL);

	ret = read(fd, buf, FILE_SIZE);

	t = utime_since_now(&tv;;

	if (ret < 0) {

		perror("read");

		return -1;

	} else if (ret != FILE_SIZE) {

		fprintf(stderr, "short read1: %d\n", ret);

		return -1;

	}

	return t;

}

static int test_fadvise(struct io_uring *ring, const char *filename)

{

	unsigned long cached_read, uncached_read, cached_read2;

	int fd, ret;

	char *buf;

	fd = open(filename, O_RDONLY);

	if (fd < 0) {

		perror("open");

		return 1;

	}

	buf = malloc(FILE_SIZE);

	cached_read = do_read(fd, buf);

	if (cached_read == -1)

		return 1;

	ret = do_fadvise(ring, fd, 0, FILE_SIZE, POSIX_FADV_DONTNEED);

	if (ret)

		return 1;

	uncached_read = do_read(fd, buf);

	if (uncached_read == -1)

		return 1;

	ret = do_fadvise(ring, fd, 0, FILE_SIZE, POSIX_FADV_DONTNEED);

	if (ret)

		return 1;

	ret = do_fadvise(ring, fd, 0, FILE_SIZE, POSIX_FADV_WILLNEED);

	if (ret)

		return 1;

	fsync(fd);

	cached_read2 = do_read(fd, buf);

	if (cached_read2 == -1)

		return 1;

	if (cached_read < uncached_read &&

	    cached_read2 < uncached_read)

		return 0;

	return 2;

}

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

{

	struct io_uring ring;

	int ret, i, good, bad;

	char *fname;

	if (argc > 1) {

		fname = argv[1];

	} else {

		fname = ".fadvise.tmp";

		if (create_file(".fadvise.tmp")) {

			fprintf(stderr, "file creation failed\n");

			goto err;

		}

	}

	if (io_uring_queue_init(8, &ring, 0)) {

		fprintf(stderr, "ring creation failed\n");

		goto err;

	}

	good = bad = 0;

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

		ret = test_fadvise(&ring, fname);

		if (ret == 1) {

			fprintf(stderr, "read_fadvise failed\n");

			goto err;

		} else if (!ret)

			good++;

		else if (ret == 2)

			bad++;

		if (i >= MIN_LOOPS && !bad)

			break;

	}

	if (bad > good) {

		fprintf(stderr, "Suspicious timings\n");

		goto err;

	}

	if (fname != argv[1])

		unlink(fname);

	io_uring_queue_exit(&ring);

	return 0;

err:

	if (fname != argv[1])

		unlink(fname);

	return 1;

}