/*
 * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
 * Copyright (c) 2016-2020 The strace developers.
 * All rights reserved.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "tests.h"

#ifdef HAVE_PREADV

# include <fcntl.h>
# include <stdio.h>
# include <sys/uio.h>
# include <unistd.h>

# define LEN 8

static void
print_iov(const struct iovec *iov)
{
	unsigned int i;
	unsigned char *buf = iov->iov_base;

	fputs("{iov_base=\"", stdout);
	for (i = 0; i < iov->iov_len; ++i)
		printf("\\%d", (int) buf[i]);
	printf("\", iov_len=%u}", (unsigned) iov->iov_len);
}

static void
print_iovec(const struct iovec *iov, unsigned int cnt)
{
	unsigned int i;
	putchar('[');
	for (i = 0; i < cnt; ++i) {
		if (i)
			fputs(", ", stdout);
		print_iov(&iov[i]);
	}
	putchar(']');
}

int
main(void)
{
	const off_t offset = 0xdefaceddeadbeefLL;
	char *buf = tail_alloc(LEN);
	TAIL_ALLOC_OBJECT_CONST_PTR(struct iovec, iov);
	iov->iov_base = buf;
	iov->iov_len = LEN;

	(void) close(0);
	if (open("/dev/zero", O_RDONLY))
		perror_msg_and_fail("open");

	if (preadv(0, iov, 1, offset) != LEN)
		perror_msg_and_fail("preadv");
	printf("preadv(0, ");
	print_iovec(iov, 1);
	printf(", 1, %lld) = %u\n", (long long) offset, LEN);

	if (preadv(0, iov, 1, -1) != -1)
		perror_msg_and_fail("preadv");
	printf("preadv(0, [{iov_base=%p, iov_len=%zu}], 1, -1) = "
	       "-1 EINVAL (%m)\n", iov->iov_base, iov->iov_len);

	if (preadv(0, NULL, 1, -2) != -1)
		perror_msg_and_fail("preadv");
	printf("preadv(0, NULL, 1, -2) = -1 EINVAL (%m)\n");

	if (preadv(0, iov, 0, -3) != -1)
		perror_msg_and_fail("preadv");
	printf("preadv(0, [], 0, -3) = -1 EINVAL (%m)\n");

	int fd = create_tmpfile(O_RDWR);

	static const char w[] = "0123456789abcde";
	if (write(fd, w, LENGTH_OF(w)) != LENGTH_OF(w))
		perror_msg_and_fail("write");

	static const char r0_c[] = "01234567";
	static const char r1_c[] = "89abcde";

	const unsigned int r_len = (LENGTH_OF(w) + 1) / 2;
	void *r0 = tail_alloc(r_len);
	const struct iovec r0_iov_[] = {
		{
			.iov_base = r0,
			.iov_len = r_len
		}
	};
	const struct iovec *r_iov = tail_memdup(r0_iov_, sizeof(r0_iov_));

	long rc;

	rc = preadv(fd, r_iov, ARRAY_SIZE(r0_iov_), 0);
	if (rc != (int) r_len)
		perror_msg_and_fail("preadv: expected %u, returned %ld",
				    r_len, rc);
	printf("preadv(%d, [{iov_base=\"%s\", iov_len=%u}], %u, 0) = %u\n",
	       fd, r0_c, r_len, (unsigned int) ARRAY_SIZE(r0_iov_), r_len);

	void *r1 = tail_alloc(r_len);
	void *r2 = tail_alloc(LENGTH_OF(w));
	const struct iovec r1_iov_[] = {
		{
			.iov_base = r1,
			.iov_len = r_len
		},
		{
			.iov_base = r2,
			.iov_len = LENGTH_OF(w)
		}
	};
	r_iov = tail_memdup(r1_iov_, sizeof(r1_iov_));

	rc = preadv(fd, r_iov, ARRAY_SIZE(r1_iov_), r_len);
	if (rc != (int) LENGTH_OF(w) - (int) r_len)
		perror_msg_and_fail("preadv: expected %d, returned %ld",
				    (int) LENGTH_OF(w) - r_len, rc);
	printf("preadv(%d, [{iov_base=\"%s\", iov_len=%u}"
	       ", {iov_base=\"\", iov_len=%u}], %u, %u) = %u\n",
	       fd, r1_c, r_len, LENGTH_OF(w),
	       (unsigned int) ARRAY_SIZE(r1_iov_),
	       r_len, LENGTH_OF(w) - r_len);

	puts("+++ exited with 0 +++");
	return 0;
}

#else

SKIP_MAIN_UNDEFINED("HAVE_PREADV")

#endif
