/* SPDX-License-Identifier: MIT */
/*
 * Check that IORING_OP_ACCEPT works, and send some data across to verify we
 * didn't get a junk fd.
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/un.h>
#include <netinet/tcp.h>
#include <netinet/in.h>

#include "liburing.h"

static int no_accept;

struct data {
	char buf[128];
	struct iovec iov;
};

static void queue_send(struct io_uring *ring, int fd)
{
	struct io_uring_sqe *sqe;
	struct data *d;

	d = malloc(sizeof(*d));
	d->iov.iov_base = d->buf;
	d->iov.iov_len = sizeof(d->buf);

	sqe = io_uring_get_sqe(ring);
	io_uring_prep_writev(sqe, fd, &d->iov, 1, 0);
}

static void queue_recv(struct io_uring *ring, int fd)
{
	struct io_uring_sqe *sqe;
	struct data *d;

	d = malloc(sizeof(*d));
	d->iov.iov_base = d->buf;
	d->iov.iov_len = sizeof(d->buf);

	sqe = io_uring_get_sqe(ring);
	io_uring_prep_readv(sqe, fd, &d->iov, 1, 0);
}

static int accept_conn(struct io_uring *ring, int fd)
{
	struct io_uring_sqe *sqe;
	struct io_uring_cqe *cqe;
	int ret;

	sqe = io_uring_get_sqe(ring);
	io_uring_prep_accept(sqe, fd, NULL, NULL, 0);

	assert(io_uring_submit(ring) != -1);

	assert(!io_uring_wait_cqe(ring, &cqe));
	ret = cqe->res;
	io_uring_cqe_seen(ring, cqe);
	return ret;
}

static int start_accept_listen(struct sockaddr_in *addr, int port_off)
{
	int fd;

	fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);

	int32_t val = 1;
	assert(setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val)) != -1);
	assert(setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) != -1);

	struct sockaddr_in laddr;

	if (!addr)
		addr = &laddr;

	addr->sin_family = AF_INET;
	addr->sin_port = 0x1235 + port_off;
	addr->sin_addr.s_addr = 0x0100007fU;

	assert(bind(fd, (struct sockaddr*)addr, sizeof(*addr)) != -1);
	assert(listen(fd, 128) != -1);

	return fd;
}

static int test(struct io_uring *ring, int accept_should_error)
{
	struct io_uring_cqe *cqe;
	struct sockaddr_in addr;
	uint32_t head;
	uint32_t count = 0;
	int done = 0;
	int p_fd[2];

	int32_t val, recv_s0 = start_accept_listen(&addr, 0);

	p_fd[1] = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);

	val = 1;
	assert(setsockopt(p_fd[1], IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val)) != -1);

	int32_t flags = fcntl(p_fd[1], F_GETFL, 0);
	assert(flags != -1);

	flags |= O_NONBLOCK;
	assert(fcntl(p_fd[1], F_SETFL, flags) != -1);

	assert(connect(p_fd[1], (struct sockaddr*)&addr, sizeof(addr)) == -1);

	flags = fcntl(p_fd[1], F_GETFL, 0);
	assert(flags != -1);

	flags &= ~O_NONBLOCK;
	assert(fcntl(p_fd[1], F_SETFL, flags) != -1);

	p_fd[0] = accept_conn(ring, recv_s0);
	if (p_fd[0] == -EINVAL) {
		if (accept_should_error)
			goto out;
		fprintf(stdout, "Accept not supported, skipping\n");
		no_accept = 1;
		goto out;
	} else if (p_fd[0] < 0) {
		if (accept_should_error &&
		    (p_fd[0] == -EBADF || p_fd[0] == -EINVAL))
			goto out;
		fprintf(stderr, "Accept got %d\n", p_fd[0]);
		goto err;
	}

	queue_send(ring, p_fd[1]);
	queue_recv(ring, p_fd[0]);

	assert(io_uring_submit_and_wait(ring, 2) != -1);

	while (count < 2) {
		io_uring_for_each_cqe(ring, head, cqe) {
			if (cqe->res < 0) {
				fprintf(stderr, "Got cqe res %d\n", cqe->res);
				done = 1;
				break;
			}
			assert(cqe->res == 128);
			count++;
		}

		assert(count <= 2);
		io_uring_cq_advance(ring, count);
		if (done)
			goto err;
	}

out:
	close(p_fd[0]);
	close(p_fd[1]);
	return 0;
err:
	close(p_fd[0]);
	close(p_fd[1]);
	return 1;
}

static void sig_alrm(int sig)
{
	exit(0);
}

static int test_accept_pending_on_exit(void)
{
	struct io_uring m_io_uring;
	struct io_uring_cqe *cqe;
	struct io_uring_sqe *sqe;
	int fd;

	assert(io_uring_queue_init(32, &m_io_uring, 0) >= 0);

	fd = start_accept_listen(NULL, 0);

	sqe = io_uring_get_sqe(&m_io_uring);
	io_uring_prep_accept(sqe, fd, NULL, NULL, 0);
	assert(io_uring_submit(&m_io_uring) != -1);

	signal(SIGALRM, sig_alrm);
	alarm(1);
	assert(!io_uring_wait_cqe(&m_io_uring, &cqe));
	io_uring_cqe_seen(&m_io_uring, cqe);

	io_uring_queue_exit(&m_io_uring);
	return 0;
}

/*
 * Test issue many accepts and see if we handle cancellation on exit
 */
static int test_accept_many(unsigned nr, unsigned usecs)
{
	struct io_uring m_io_uring;
	struct io_uring_cqe *cqe;
	struct io_uring_sqe *sqe;
	unsigned long cur_lim;
	struct rlimit rlim;
	int *fds, i, ret = 0;

	if (getrlimit(RLIMIT_NPROC, &rlim) < 0) {
		perror("getrlimit");
		return 1;
	}

	cur_lim = rlim.rlim_cur;
	rlim.rlim_cur = nr / 4;

	if (setrlimit(RLIMIT_NPROC, &rlim) < 0) {
		perror("setrlimit");
		return 1;
	}

	assert(io_uring_queue_init(2 * nr, &m_io_uring, 0) >= 0);

	fds = calloc(nr, sizeof(int));

	for (i = 0; i < nr; i++)
		fds[i] = start_accept_listen(NULL, i);

	for (i = 0; i < nr; i++) {
		sqe = io_uring_get_sqe(&m_io_uring);
		io_uring_prep_accept(sqe, fds[i], NULL, NULL, 0);
		sqe->user_data = 1 + i;
		assert(io_uring_submit(&m_io_uring) == 1);
	}

	if (usecs)
		usleep(usecs);

	for (i = 0; i < nr; i++) {
		if (io_uring_peek_cqe(&m_io_uring, &cqe))
			break;
		if (cqe->res != -ECANCELED) {
			fprintf(stderr, "Expected cqe to be cancelled\n");
			goto err;
		}
		io_uring_cqe_seen(&m_io_uring, cqe);
	}
out:
	rlim.rlim_cur = cur_lim;
	if (setrlimit(RLIMIT_NPROC, &rlim) < 0) {
		perror("setrlimit");
		return 1;
	}

	free(fds);
	io_uring_queue_exit(&m_io_uring);
	return ret;
err:
	ret = 1;
	goto out;
}

static int test_accept_cancel(unsigned usecs)
{
	struct io_uring m_io_uring;
	struct io_uring_cqe *cqe;
	struct io_uring_sqe *sqe;
	int fd, i;

	assert(io_uring_queue_init(32, &m_io_uring, 0) >= 0);

	fd = start_accept_listen(NULL, 0);

	sqe = io_uring_get_sqe(&m_io_uring);
	io_uring_prep_accept(sqe, fd, NULL, NULL, 0);
	sqe->user_data = 1;
	assert(io_uring_submit(&m_io_uring) == 1);

	if (usecs)
		usleep(usecs);

	sqe = io_uring_get_sqe(&m_io_uring);
	io_uring_prep_cancel(sqe, (void *) 1, 0);
	sqe->user_data = 2;
	assert(io_uring_submit(&m_io_uring) == 1);

	for (i = 0; i < 2; i++) {
		assert(!io_uring_wait_cqe(&m_io_uring, &cqe));
		/*
		 * Two cases here:
		 *
		 * 1) We cancel the accept4() before it got started, we should
		 *    get '0' for the cancel request and '-ECANCELED' for the
		 *    accept request.
		 * 2) We cancel the accept4() after it's already running, we
		 *    should get '-EALREADY' for the cancel request and
		 *    '-EINTR' for the accept request.
		 */
		if (cqe->user_data == 1) {
			if (cqe->res != -EINTR && cqe->res != -ECANCELED) {
				fprintf(stderr, "Cancelled accept got %d\n", cqe->res);
				goto err;
			}
		} else if (cqe->user_data == 2) {
			if (cqe->res != -EALREADY && cqe->res != 0) {
				fprintf(stderr, "Cancel got %d\n", cqe->res);
				goto err;
			}
		}
		io_uring_cqe_seen(&m_io_uring, cqe);
	}

	io_uring_queue_exit(&m_io_uring);
	return 0;
err:
	io_uring_queue_exit(&m_io_uring);
	return 1;
}

static int test_accept(void)
{
	struct io_uring m_io_uring;
	int ret;

	assert(io_uring_queue_init(32, &m_io_uring, 0) >= 0);
	ret = test(&m_io_uring, 0);
	io_uring_queue_exit(&m_io_uring);
	return ret;
}

static int test_accept_sqpoll(void)
{
	struct io_uring m_io_uring;
	int ret;

	ret = io_uring_queue_init(32, &m_io_uring, IORING_SETUP_SQPOLL);
	if (ret && geteuid()) {
		printf("%s: skipped, not root\n", __FUNCTION__);
		return 0;
	} else if (ret)
		return ret;

	ret = test(&m_io_uring, 1);
	io_uring_queue_exit(&m_io_uring);
	return ret;
}

int main(int argc, char *argv[])
{
	int ret;

	ret = test_accept();
	if (ret) {
		fprintf(stderr, "test_accept failed\n");
		return ret;
	}
	if (no_accept)
		return 0;

	ret = test_accept_sqpoll();
	if (ret) {
		fprintf(stderr, "test_accept_sqpoll failed\n");
		return ret;
	}

	ret = test_accept_cancel(0);
	if (ret) {
		fprintf(stderr, "test_accept_cancel nodelay failed\n");
		return ret;
	}

	ret = test_accept_cancel(10000);
	if (ret) {
		fprintf(stderr, "test_accept_cancel delay failed\n");
		return ret;
	}

	ret = test_accept_many(128, 0);
	if (ret) {
		fprintf(stderr, "test_accept_many failed\n");
		return ret;
	}

	ret = test_accept_many(128, 100000);
	if (ret) {
		fprintf(stderr, "test_accept_many failed\n");
		return ret;
	}

	ret = test_accept_pending_on_exit();
	if (ret) {
		fprintf(stderr, "test_accept_pending_on_exit failed\n");
		return ret;
	}

	return 0;
}