/* SPDX-License-Identifier: MIT */

/*

 * Test reads that will punt to blocking context, with immediate overwrite

 * of iovec->iov_base to NULL. If the kernel doesn't properly handle

 * reuse of the iovec, we should get -EFAULT.

 */

#include <unistd.h>

#include <fcntl.h>

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <pthread.h>

#include <sys/time.h>

#include "liburing.h"

#define STR_SIZE	32768

#define FILE_SIZE	65536

struct thread_data {

	int fd1, fd2;

	volatile int do_exit;

};

static void *flusher(void *__data)

{

	struct thread_data *data = __data;

	int i = 0;

	while (!data->do_exit) {

		posix_fadvise(data->fd1, 0, FILE_SIZE, POSIX_FADV_DONTNEED);

		posix_fadvise(data->fd2, 0, FILE_SIZE, POSIX_FADV_DONTNEED);

		i++;

	}

	return NULL;

}

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 char str1[STR_SIZE];

static char str2[STR_SIZE];

static struct io_uring ring;

static int prep(int fd, char *str)

{

	struct io_uring_sqe *sqe;

	struct iovec iov = {

		.iov_base = str,

		.iov_len = STR_SIZE,

	};

	int ret;

	sqe = io_uring_get_sqe(&ring);

	io_uring_prep_readv(sqe, fd, &iov, 1, 0);

	sqe->user_data = fd;

	ret = io_uring_submit(&ring);

	if (ret != 1) {

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

		return 1;

	}

	iov.iov_base = NULL;

	return 0;

}

static int wait_nr(int nr)

{

	int i, ret;

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

		struct io_uring_cqe *cqe;

		ret = io_uring_wait_cqe(&ring, &cqe);

		if (ret)

			return ret;

		if (cqe->res < 0) {

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

			return 1;

		}

		io_uring_cqe_seen(&ring, cqe);

	}

	return 0;

}

static unsigned long long mtime_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 *= 1000;

	usec /= 1000;

	return sec + usec;

}

static unsigned long long mtime_since_now(struct timeval *tv)

{

	struct timeval end;

	gettimeofday(&end, NULL);

	return mtime_since(tv, &end;;

}

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

{

	struct thread_data data;

	int fd1, fd2, ret, i;

	struct timeval tv;

	pthread_t thread;

	void *tret;

	if (argc > 1)

		return 0;

	ret = io_uring_queue_init(32, &ring, 0);

	if (ret) {

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

		return 1;

	}

	if (create_file(".reuse.1")) {

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

		goto err;

	}

	if (create_file(".reuse.2")) {

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

		goto err;

	}

	fd1 = open(".reuse.1", O_RDONLY);

	fd2 = open(".reuse.2", O_RDONLY);

	data.fd1 = fd1;

	data.fd2 = fd2;

	data.do_exit = 0;

	pthread_create(&thread, NULL, flusher, &data);

	usleep(10000);

	gettimeofday(&tv, NULL);

	for (i = 0; i < 1000; i++) {

		ret = prep(fd1, str1);

		if (ret) {

			fprintf(stderr, "prep1 failed: %d\n", ret);

			goto err;

		}

		ret = prep(fd2, str2);

		if (ret) {

			fprintf(stderr, "prep1 failed: %d\n", ret);

			goto err;

		}

		ret = wait_nr(2);

		if (ret) {

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

			goto err;

		}

		if (mtime_since_now(&tv) > 5000)

			break;

	}

	data.do_exit = 1;

	pthread_join(thread, &tret);

	close(fd2);

	close(fd1);

	io_uring_queue_exit(&ring);

	unlink(".reuse.1");

	unlink(".reuse.2");

	return 0;

err:

	io_uring_queue_exit(&ring);

	unlink(".reuse.1");

	unlink(".reuse.2");

	return 1;

}