/*
 * Copyright (C) 2013-2020 Canonical, Ltd.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * This code is a complete clean re-write of the stress tool by
 * Colin Ian King <colin.king@canonical.com> and attempts to be
 * backwardly compatible with the stress tool by Amos Waterland
 * <apw@rossby.metr.ou.edu> but has more stress tests and more
 * functionality.
 *
 */
#include "stress-ng.h"

static const stress_help_t help[] = {
	{ NULL,	"splice N",	  "start N workers reading/writing using splice" },
	{ NULL,	"splice-ops N",	  "stop after N bogo splice operations" },
	{ NULL,	"splice-bytes N", "number of bytes to transfer per splice call" },
	{ NULL,	NULL,		  NULL }
};

static int stress_set_splice_bytes(const char *opt)
{
	size_t splice_bytes;

	splice_bytes = (size_t)stress_get_uint64_byte_memory(opt, 1);
	stress_check_range_bytes("splice-bytes", splice_bytes,
		MIN_SPLICE_BYTES, MAX_MEM_LIMIT);
	return stress_set_setting("splice-bytes", TYPE_ID_SIZE_T, &splice_bytes);
}

static const stress_opt_set_func_t opt_set_funcs[] = {
	{ OPT_splice_bytes,	stress_set_splice_bytes },
	{ 0,			NULL }
};

#if defined(HAVE_SPLICE) &&	\
    defined(SPLICE_F_MOVE)

/*
 *  stress_splice
 *	stress copying of /dev/zero to /dev/null
 */
static int stress_splice(const stress_args_t *args)
{
	int fd_in, fd_out, fds[2];
	size_t splice_bytes = DEFAULT_SPLICE_BYTES;

	if (!stress_get_setting("splice-bytes", &splice_bytes)) {
		if (g_opt_flags & OPT_FLAGS_MAXIMIZE)
			splice_bytes = MAX_SPLICE_BYTES;
		if (g_opt_flags & OPT_FLAGS_MINIMIZE)
			splice_bytes = MIN_SPLICE_BYTES;
	}
	splice_bytes /= args->num_instances;
	if (splice_bytes < MIN_SPLICE_BYTES)
		splice_bytes = MIN_SPLICE_BYTES;

	if (pipe(fds) < 0) {
		pr_fail_err("pipe");
		return EXIT_FAILURE;
	}

	if ((fd_in = open("/dev/zero", O_RDONLY)) < 0) {
		(void)close(fds[0]);
		(void)close(fds[1]);
		pr_fail_err("open");
		return EXIT_FAILURE;
	}
	if ((fd_out = open("/dev/null", O_WRONLY)) < 0) {
		(void)close(fd_in);
		(void)close(fds[0]);
		(void)close(fds[1]);
		pr_fail_err("open");
		return EXIT_FAILURE;
	}

	do {
		ssize_t ret;

		ret = splice(fd_in, NULL, fds[1], NULL,
				splice_bytes, SPLICE_F_MOVE);
		if (ret < 0)
			break;

		ret = splice(fds[0], NULL, fd_out, NULL,
				splice_bytes, SPLICE_F_MOVE);
		if (ret < 0)
			break;

		inc_counter(args);
	} while (keep_stressing());
	(void)close(fd_out);
	(void)close(fd_in);
	(void)close(fds[0]);
	(void)close(fds[1]);

	return EXIT_SUCCESS;
}

stressor_info_t stress_splice_info = {
	.stressor = stress_splice,
	.class = CLASS_PIPE_IO | CLASS_OS,
	.opt_set_funcs = opt_set_funcs,
	.help = help
};
#else
stressor_info_t stress_splice_info = {
	.stressor = stress_not_implemented,
	.class = CLASS_PIPE_IO | CLASS_OS,
	.opt_set_funcs = opt_set_funcs,
	.help = help
};
#endif
