src/sys/dev/bio.c

/*	$OpenBSD: bio.c,v 1.19 2023/11/15 23:57:45 dlg Exp $	*/

/*
 * Copyright (c) 2002 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 2012 Joel Sing <jsing@openbsd.org>.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/* A device controller ioctl tunnelling device.  */

#include <sys/param.h>
#include <sys/device.h>
#include <sys/ioctl.h>
#include <sys/malloc.h>
#include <sys/tree.h>
#include <sys/systm.h>

#include <dev/biovar.h>

struct bio_mapping {
	RBT_ENTRY(bio_mapping) bm_link;
	uintptr_t bm_cookie;
	struct device *bm_dev;
	int (*bm_ioctl)(struct device *, u_long, caddr_t);
};

RBT_HEAD(bio_mappings, bio_mapping);

static inline int
bio_cookie_cmp(const struct bio_mapping *a, const struct bio_mapping *b)
{
	if (a->bm_cookie < b->bm_cookie)
		return (1);
	if (a->bm_cookie > b->bm_cookie)
		return (-1);
	return (0);
}

RBT_PROTOTYPE(bio_mappings, bio_mapping, bm_link, bio_cookie_cmp);

struct bio_mappings bios = RBT_INITIALIZER();

void	bioattach(int);
int	bioclose(dev_t, int, int, struct proc *);
int	bioioctl(dev_t, u_long, caddr_t, int, struct proc *);
int	bioopen(dev_t, int, int, struct proc *);

int	bio_delegate_ioctl(struct bio_mapping *, u_long, caddr_t);
struct	bio_mapping *bio_lookup(char *);
struct	bio_mapping *bio_validate(void *);

void
bioattach(int nunits)
{
}

int
bioopen(dev_t dev, int flags, int mode, struct proc *p)
{
	return (0);
}

int
bioclose(dev_t dev, int flags, int mode, struct proc *p)
{
	return (0);
}

int
bioioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
{
	struct bio_mapping *bm;
	struct bio_locate *locate;
	struct bio *bio;
	char name[16];
	int error;

	switch (cmd) {
	case BIOCLOCATE:
		locate = (struct bio_locate *)addr;
		error = copyinstr(locate->bl_name, name, sizeof name, NULL);
		if (error != 0)
			return (error);
		bm = bio_lookup(name);
		if (bm == NULL)
			return (ENOENT);
		locate->bl_bio.bio_cookie = (void *)bm->bm_cookie;
		break;

	default:
		bio = (struct bio *)addr;
		bm = bio_validate(bio->bio_cookie);
		if (bm == NULL)
			return (ENOENT);

		error = bio_delegate_ioctl(bm, cmd, addr);
		break;
	}

	return (0);
}

int
bio_register(struct device *dev, int (*ioctl)(struct device *, u_long, caddr_t))
{
	struct bio_mapping *bm;

	bm = malloc(sizeof *bm, M_DEVBUF, M_NOWAIT);
	if (bm == NULL)
		return (ENOMEM);
	bm->bm_dev = dev;
	bm->bm_ioctl = ioctl;
	do {
		bm->bm_cookie = arc4random();
		/* lets hope we don't have 4 billion bio_registers */
	} while (RBT_INSERT(bio_mappings, &bios, bm) != NULL);
	return (0);
}

void
bio_unregister(struct device *dev)
{
	struct bio_mapping *bm, *next;

	RBT_FOREACH_SAFE(bm, bio_mappings, &bios, next) {
		if (dev == bm->bm_dev) {
			RBT_REMOVE(bio_mappings, &bios, bm);
			free(bm, M_DEVBUF, sizeof(*bm));
		}
	}
}

struct bio_mapping *
bio_lookup(char *name)
{
	struct bio_mapping *bm;

	RBT_FOREACH(bm, bio_mappings, &bios) {
		if (strcmp(name, bm->bm_dev->dv_xname) == 0)
			return (bm);
	}

	return (NULL);
}

struct bio_mapping *
bio_validate(void *cookie)
{
	struct bio_mapping key = { .bm_cookie = (uintptr_t)cookie };

	return (RBT_FIND(bio_mappings, &bios, &key));
}

int
bio_delegate_ioctl(struct bio_mapping *bm, u_long cmd, caddr_t addr)
{
	return (bm->bm_ioctl(bm->bm_dev, cmd, addr));
}

void
bio_info(struct bio_status *bs, int print, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	bio_status(bs, print, BIO_MSG_INFO, fmt, &ap);
	va_end(ap);
}

void
bio_warn(struct bio_status *bs, int print, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	bio_status(bs, print, BIO_MSG_WARN, fmt, &ap);
	va_end(ap);
}

void
bio_error(struct bio_status *bs, int print, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	bio_status(bs, print, BIO_MSG_ERROR, fmt, &ap);
	va_end(ap);
}

void
bio_status_init(struct bio_status *bs, struct device *dv)
{
	bzero(bs, sizeof(struct bio_status));

	bs->bs_status = BIO_STATUS_UNKNOWN;

	strlcpy(bs->bs_controller, dv->dv_xname, sizeof(bs->bs_controller));
}

void
bio_status(struct bio_status *bs, int print, int msg_type, const char *fmt,
    va_list *ap)
{
	int idx;

	if (bs->bs_msg_count >= BIO_MSG_COUNT) {
		printf("%s: insufficient message buffers\n", bs->bs_controller);
		return;
	}

	idx = bs->bs_msg_count++;

	bs->bs_msgs[idx].bm_type = msg_type;
	vsnprintf(bs->bs_msgs[idx].bm_msg, BIO_MSG_LEN, fmt, *ap);

	if (print)
		printf("%s: %s\n", bs->bs_controller, bs->bs_msgs[idx].bm_msg);
}

RBT_GENERATE(bio_mappings, bio_mapping, bm_link, bio_cookie_cmp);