ardix/kernel/fs/write.c

/* SPDX-License-Identifier: BSD-3-Clause */
/* See the end of this file for copyright, licensing, and warranty information. */

#include <ardix/malloc.h>
#include <ardix/serial.h>
#include <ardix/syscall.h>
#include <ardix/userspace.h>

#include <errno.h>
#include <stddef.h>
#include <toolchain.h>

ssize_t sys_write(int fd, __user const void *buf, size_t len, size_t off)
{
	ssize_t ret;
	void *copy;

	if (fd != 1) /* we only support stdout (serial console) right now ... */
		return -ENOTSUP;
	if (off != 0) /* ... and the serial console doesn't support seeking */
		return -ESPIPE;

	copy = malloc(len);
	if (copy == NULL)
		return -ENOMEM;
	ret = (ssize_t)copy_from_user(copy, buf, (size_t)len);

	/* TODO: reschedule if blocking */
	ret = serial_write(serial_default_interface, copy, (size_t)ret);

	return ret;
}

/*
 * Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its contributors may be
 *    used to endorse or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */