xref: /src/sys/dev/dm/device-mapper.c

/*        $NetBSD: device-mapper.c,v 1.62 2021/05/07 09:54:43 hannken Exp $ */

/*
 * Copyright (c) 2010 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Adam Hamsik.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * I want to say thank you to all people who helped me with this project.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/dkio.h>
#include <sys/disk.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/ioccom.h>
#include <sys/kmem.h>
#include <sys/kauth.h>

#include "netbsd-dm.h"
#include "dm.h"
#include "ioconf.h"

static dev_type_open(dmopen);
static dev_type_close(dmclose);
static dev_type_read(dmread);
static dev_type_write(dmwrite);
static dev_type_ioctl(dmioctl);
static dev_type_strategy(dmstrategy);
static dev_type_size(dmsize);

/* attach and detach routines */
#ifdef _MODULE
static int dmdestroy(void);
#endif

static void dm_doinit(void);

static int dm_cmd_to_fun(prop_dictionary_t);
static int disk_ioctl_switch(dev_t, unsigned long, void *);
static void dmminphys(struct buf *);

/* CF attach/detach functions used for power management */
static int dm_detach(device_t, int);
static void dm_attach(device_t, device_t, void *);
static int dm_match(device_t, cfdata_t, void *);

/* ***Variable-definitions*** */
const struct bdevsw dm_bdevsw = {
	.d_open = dmopen,
	.d_close = dmclose,
	.d_strategy = dmstrategy,
	.d_ioctl = dmioctl,
	.d_dump = nodump,
	.d_psize = dmsize,
	.d_discard = nodiscard,
	.d_flag = D_DISK | D_MPSAFE
};

const struct cdevsw dm_cdevsw = {
	.d_open = dmopen,
	.d_close = dmclose,
	.d_read = dmread,
	.d_write = dmwrite,
	.d_ioctl = dmioctl,
	.d_stop = nostop,
	.d_tty = notty,
	.d_poll = nopoll,
	.d_mmap = nommap,
	.d_kqfilter = nokqfilter,
	.d_discard = nodiscard,
	.d_flag = D_DISK | D_MPSAFE
};

const struct dkdriver dmdkdriver = {
	.d_strategy = dmstrategy
};

CFATTACH_DECL3_NEW(dm, 0,
     dm_match, dm_attach, dm_detach, NULL, NULL, NULL,
     DVF_DETACH_SHUTDOWN);

/*
 * This structure is used to translate command sent to kernel driver in
 * <key>command</key>
 * <value></value>
 * to function which I can call, and if the command is allowed for
 * non-superusers.
 */
/*
 * This array is used to translate cmd to function pointer.
 *
 * Interface between libdevmapper and lvm2tools uses different
 * names for one IOCTL call because libdevmapper do another thing
 * then. When I run "info" or "mknodes" libdevmapper will send same
 * ioctl to kernel but will do another things in userspace.
 *
 */
static const struct cmd_function {
	const char *cmd;
	int  (*fn)(prop_dictionary_t);
	int  allowed;
} cmd_fn[] = {
	{ .cmd = "version", .fn = NULL,                   .allowed = 1 },
	{ .cmd = "targets", .fn = dm_list_versions_ioctl, .allowed = 1 },
	{ .cmd = "create",  .fn = dm_dev_create_ioctl,    .allowed = 0 },
	{ .cmd = "info",    .fn = dm_dev_status_ioctl,    .allowed = 1 },
	{ .cmd = "mknodes", .fn = dm_dev_status_ioctl,    .allowed = 1 },
	{ .cmd = "names",   .fn = dm_dev_list_ioctl,      .allowed = 1 },
	{ .cmd = "suspend", .fn = dm_dev_suspend_ioctl,   .allowed = 0 },
	{ .cmd = "remove",  .fn = dm_dev_remove_ioctl,    .allowed = 0 },
	{ .cmd = "rename",  .fn = dm_dev_rename_ioctl,    .allowed = 0 },
	{ .cmd = "resume",  .fn = dm_dev_resume_ioctl,    .allowed = 0 },
	{ .cmd = "clear",   .fn = dm_table_clear_ioctl,   .allowed = 0 },
	{ .cmd = "deps",    .fn = dm_table_deps_ioctl,    .allowed = 1 },
	{ .cmd = "reload",  .fn = dm_table_load_ioctl,    .allowed = 0 },
	{ .cmd = "status",  .fn = dm_table_status_ioctl,  .allowed = 1 },
	{ .cmd = "table",   .fn = dm_table_status_ioctl,  .allowed = 1 },
	{ .cmd = NULL,      .fn = NULL,                   .allowed = 0 },
};

#ifdef _MODULE
#include <sys/module.h>

/* Autoconf defines */
CFDRIVER_DECL(dm, DV_DISK, NULL);

MODULE(MODULE_CLASS_DRIVER, dm, "dk_subr");

/* New module handle routine */
static int
dm_modcmd(modcmd_t cmd, void *arg)
{
#ifdef _MODULE
	int error;
	devmajor_t bmajor, cmajor;

	error = 0;
	bmajor = -1;
	cmajor = -1;

	switch (cmd) {
	case MODULE_CMD_INIT:
		error = config_cfdriver_attach(&dm_cd);
		if (error)
			break;

		error = config_cfattach_attach(dm_cd.cd_name, &dm_ca);
		if (error) {
			aprint_error("%s: unable to register cfattach\n",
			    dm_cd.cd_name);
			return error;
		}

		error = devsw_attach(dm_cd.cd_name, &dm_bdevsw, &bmajor,
		    &dm_cdevsw, &cmajor);
		if (error == EEXIST)
			error = 0;
		if (error) {
			config_cfattach_detach(dm_cd.cd_name, &dm_ca);
			config_cfdriver_detach(&dm_cd);
			break;
		}
		dm_doinit();
		break;
	case MODULE_CMD_FINI:
		/*
		 * Disable unloading of dm module if there are any devices
		 * defined in driver. This is probably too strong we need
		 * to disable auto-unload only if there is mounted dm device
		 * present.
		 */
		if (dm_dev_counter > 0)
			return EBUSY;
		/* race window here */

		error = dmdestroy();
		if (error)
			break;

		config_cfdriver_detach(&dm_cd);

		devsw_detach(&dm_bdevsw, &dm_cdevsw);
		break;
	case MODULE_CMD_STAT:
		return ENOTTY;
	default:
		return ENOTTY;
	}

	return error;
#else
	return ENOTTY;
#endif
}
#endif /* _MODULE */

/*
 * dm_match:
 *
 *	Autoconfiguration match function for pseudo-device glue.
 */
static int
dm_match(device_t parent, cfdata_t match, void *aux)
{

	/* Pseudo-device; always present. */
	return 1;
}

/*
 * dm_attach:
 *
 *	Autoconfiguration attach function for pseudo-device glue.
 */
static void
dm_attach(device_t parent, device_t self, void *aux)
{

	if (!pmf_device_register(self, NULL, NULL))
		aprint_error_dev(self, "couldn't establish power handler\n");
}

/*
 * dm_detach:
 *
 *	Autoconfiguration detach function for pseudo-device glue.
 * This routine is called by dm_ioctl::dm_dev_remove_ioctl and by autoconf to
 * remove devices created in device-mapper.
 */
static int
dm_detach(device_t self, int flags)
{
	bool busy;
	dm_dev_t *dmv;

	dmv = dm_dev_lookup(NULL, NULL, device_unit(self));
	mutex_enter(&dmv->diskp->dk_openlock);
	busy = (dmv->diskp->dk_openmask != 0 && (flags & DETACH_FORCE) == 0);
	mutex_exit(&dmv->diskp->dk_openlock);
	dm_dev_unbusy(dmv);
	if (busy)
		return EBUSY;

	pmf_device_deregister(self);

	/* Detach device from global device list */
	if ((dmv = dm_dev_detach(self)) == NULL)
		return ENOENT;

	/* Destroy active table first.  */
	dm_table_destroy(&dmv->table_head, DM_TABLE_ACTIVE);

	/* Destroy inactive table if exits, too. */
	dm_table_destroy(&dmv->table_head, DM_TABLE_INACTIVE);

	dm_table_head_destroy(&dmv->table_head);

	/* Destroy disk device structure */
	disk_detach(dmv->diskp);
	disk_destroy(dmv->diskp);

	/* Destroy device */
	dm_dev_free(dmv);

	/* Decrement device counter After removing device */
	atomic_dec_32(&dm_dev_counter);

	return 0;
}

static void
dm_doinit(void)
{

	dm_target_init();
	dm_dev_init();
	dm_pdev_init();
}

/* attach routine */
void
dmattach(int n)
{
	int error;

	error = config_cfattach_attach(dm_cd.cd_name, &dm_ca);
	if (error)
		aprint_error("%s: unable to register cfattach\n",
		    dm_cd.cd_name);
	else
		dm_doinit();
}

#ifdef _MODULE
/* Destroy routine */
static int
dmdestroy(void)
{
	int error;

	error = config_cfattach_detach(dm_cd.cd_name, &dm_ca);
	if (error)
		return error;

	dm_dev_destroy();
	dm_pdev_destroy();
	dm_target_destroy();

	return 0;
}
#endif /* _MODULE */

static int
dmopen(dev_t dev, int flags, int mode, struct lwp *l)
{
	dm_dev_t *dmv;
	struct disk *dk;

	dmv = dm_dev_lookup(NULL, NULL, minor(dev));
	if (dmv) {
		dk = dmv->diskp;
		mutex_enter(&dk->dk_openlock);
		switch (mode) {
		case S_IFCHR:
			dk->dk_copenmask |= 1;
			break;
		case S_IFBLK:
			dk->dk_bopenmask |= 1;
			break;
		}
		dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
		mutex_exit(&dk->dk_openlock);
		dm_dev_unbusy(dmv);
	}

	aprint_debug("dm open routine called %" PRIu32 "\n", minor(dev));
	return 0;
}

static int
dmclose(dev_t dev, int flags, int mode, struct lwp *l)
{
	dm_dev_t *dmv;
	struct disk *dk;

	aprint_debug("dm close routine called %" PRIu32 "\n", minor(dev));

	dmv = dm_dev_lookup(NULL, NULL, minor(dev));
	if (dmv) {
		dk = dmv->diskp;
		mutex_enter(&dk->dk_openlock);
		switch (mode) {
		case S_IFCHR:
			dk->dk_copenmask &= ~1;
			break;
		case S_IFBLK:
			dk->dk_bopenmask &= ~1;
			break;
		}
		dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
		mutex_exit(&dk->dk_openlock);
		dm_dev_unbusy(dmv);
	}
	return 0;
}


static int
dmioctl(dev_t dev, const u_long cmd, void *data, int flag, struct lwp *l)
{
	int r;
	prop_dictionary_t dm_dict_in;

	aprint_debug("dmioctl called\n");
	KASSERT(data != NULL);

	if ((r = disk_ioctl_switch(dev, cmd, data)) == ENOTTY) {
		struct plistref *pref = (struct plistref *)data;

		switch(cmd) {
		case NETBSD_DM_IOCTL:
			aprint_debug("dm NETBSD_DM_IOCTL called\n");
			break;
		default:
			aprint_debug("dm unknown ioctl called\n");
			return ENOTTY;
			break; /* NOT REACHED */
		}

		if ((r = prop_dictionary_copyin_ioctl(pref, cmd, &dm_dict_in))
		    != 0)
			return r;

		if ((r = dm_check_version(dm_dict_in)) != 0)
			goto cleanup_exit;

		/* run ioctl routine */
		if ((r = dm_cmd_to_fun(dm_dict_in)) != 0)
			goto cleanup_exit;

cleanup_exit:
		r = prop_dictionary_copyout_ioctl(pref, cmd, dm_dict_in);
		prop_object_release(dm_dict_in);
	}

	return r;
}

/*
 * Translate command sent from libdevmapper to func.
 */
static int
dm_cmd_to_fun(prop_dictionary_t dm_dict)
{
	int i, r;
	prop_string_t command;

	if ((command = prop_dictionary_get(dm_dict, DM_IOCTL_COMMAND)) == NULL)
		return EINVAL;

	for (i = 0; cmd_fn[i].cmd != NULL; i++)
		if (prop_string_equals_string(command, cmd_fn[i].cmd))
			break;

	if (!cmd_fn[i].allowed &&
	    (r = kauth_authorize_system(kauth_cred_get(),
	    KAUTH_SYSTEM_DEVMAPPER, 0, NULL, NULL, NULL)) != 0)
		return r;

	if (cmd_fn[i].cmd == NULL)
		return EINVAL;

	aprint_debug("ioctl %s called %p\n", cmd_fn[i].cmd, cmd_fn[i].fn);
	if (cmd_fn[i].fn == NULL)
		return 0;

	return cmd_fn[i].fn(dm_dict);
}

/*
 * Check for disk specific ioctls.
 */
static int
disk_ioctl_switch(dev_t dev, unsigned long cmd, void *data)
{
	dm_dev_t *dmv;

	/* disk ioctls make sense only on block devices */
	if (minor(dev) == 0)
		return ENOTTY;

	switch(cmd) {
	case DIOCGWEDGEINFO:
	{
		struct dkwedge_info *dkw = (void *) data;

		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
			return ENODEV;

		aprint_debug("DIOCGWEDGEINFO ioctl called\n");

		strlcpy(dkw->dkw_devname, dmv->name, 16);
		strlcpy(dkw->dkw_wname, dmv->name, DM_NAME_LEN);
		strlcpy(dkw->dkw_parent, dmv->name, 16);

		dkw->dkw_offset = 0;
		dm_table_disksize(&dmv->table_head, &dkw->dkw_size, NULL);
		strcpy(dkw->dkw_ptype, DKW_PTYPE_FFS);

		dm_dev_unbusy(dmv);
		break;
	}
	case DIOCGDISKINFO:
	{
		struct plistref *pref = (struct plistref *) data;

		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
			return ENODEV;

		aprint_debug("DIOCGDISKINFO ioctl called\n");

		if (dmv->diskp->dk_info == NULL) {
			dm_dev_unbusy(dmv);
			return ENOTSUP;
		} else
			prop_dictionary_copyout_ioctl(pref, cmd,
			    dmv->diskp->dk_info);

		dm_dev_unbusy(dmv);
		break;
	}
	case DIOCCACHESYNC:
	{
		dm_table_entry_t *table_en;
		dm_table_t *tbl;

		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
			return ENODEV;

		aprint_debug("DIOCCACHESYNC ioctl called\n");

		/* Select active table */
		tbl = dm_table_get_entry(&dmv->table_head, DM_TABLE_ACTIVE);

		/*
		 * Call sync target routine for all table entries. Target sync
		 * routine basically call DIOCCACHESYNC on underlying devices.
		 */
		SLIST_FOREACH(table_en, tbl, next)
			if (table_en->target->sync)
				table_en->target->sync(table_en);
		dm_table_release(&dmv->table_head, DM_TABLE_ACTIVE);
		dm_dev_unbusy(dmv);
		break;
	}
	case DIOCGSECTORSIZE:
	{
		unsigned int secsize, *valp = data;

		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
			return ENODEV;

		aprint_debug("DIOCGSECTORSIZE ioctl called\n");

		dm_table_disksize(&dmv->table_head, NULL, &secsize);
		*valp = secsize;

		dm_dev_unbusy(dmv);
		break;
	}
	case DIOCGMEDIASIZE:
	{
		off_t *valp = data;
		uint64_t numsec;

		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
			return ENODEV;

		aprint_debug("DIOCGMEDIASIZE ioctl called\n");

		dm_table_disksize(&dmv->table_head, &numsec, NULL);
		*valp = numsec;

		dm_dev_unbusy(dmv);
		break;
	}
	default:
		aprint_debug("unknown disk_ioctl called\n");
		return ENOTTY;
		break; /* NOT REACHED */
	}

	return 0;
}

/*
 * Do all IO operations on dm logical devices.
 */
static void
dmstrategy(struct buf *bp)
{
	dm_dev_t *dmv;
	dm_table_t *tbl;
	dm_table_entry_t *table_en;
	struct buf *nestbuf;

	uint64_t buf_start, buf_len, issued_len;
	uint64_t table_start, table_end;
	uint64_t start, end;

	buf_start = bp->b_blkno * DEV_BSIZE;
	buf_len = bp->b_bcount;

	table_end = 0;
	issued_len = 0;

	if ((dmv = dm_dev_lookup(NULL, NULL, minor(bp->b_dev))) == NULL) {
		bp->b_error = EIO;
		bp->b_resid = bp->b_bcount;
		biodone(bp);
		return;
	}

	if (bounds_check_with_mediasize(bp, DEV_BSIZE,
	    dm_table_size(&dmv->table_head)) <= 0) {
		dm_dev_unbusy(dmv);
		bp->b_resid = bp->b_bcount;
		biodone(bp);
		return;
	}

	/*
	 * disk(9) is part of device structure and it can't be used without
	 * mutual exclusion, use diskp_mtx until it will be fixed.
	 */
	mutex_enter(&dmv->diskp_mtx);
	disk_busy(dmv->diskp);
	mutex_exit(&dmv->diskp_mtx);

	/* Select active table */
	tbl = dm_table_get_entry(&dmv->table_head, DM_TABLE_ACTIVE);

	 /* Nested buffers count down to zero therefore I have
	    to set bp->b_resid to maximal value. */
	bp->b_resid = bp->b_bcount;

	/*
	 * Find out what tables I want to select.
	 */
	SLIST_FOREACH(table_en, tbl, next) {
		/* I need number of bytes not blocks. */
		table_start = table_en->start * DEV_BSIZE;
		/*
		 * I have to sub 1 from table_en->length to prevent
		 * off by one error
		 */
		table_end = table_start + table_en->length * DEV_BSIZE;
		start = MAX(table_start, buf_start);
		end = MIN(table_end, buf_start + buf_len);

		aprint_debug("----------------------------------------\n");
		aprint_debug("table_start %010" PRIu64", table_end %010"
		    PRIu64 "\n", table_start, table_end);
		aprint_debug("buf_start %010" PRIu64", buf_len %010"
		    PRIu64"\n", buf_start, buf_len);
		aprint_debug("start-buf_start %010"PRIu64", end %010"
		    PRIu64"\n", start - buf_start, end);
		aprint_debug("start %010" PRIu64", end %010"
                    PRIu64"\n", start, end);
		aprint_debug("----------------------------------------\n");

		if (start < end) {
			/* create nested buffer  */
			nestbuf = getiobuf(NULL, true);
			nestiobuf_setup(bp, nestbuf, start - buf_start,
			    end - start);
			issued_len += end - start;
			/* I need number of blocks. */
			nestbuf->b_blkno = (start - table_start) / DEV_BSIZE;
			table_en->target->strategy(table_en, nestbuf);
		}
	}

	if (issued_len < buf_len)
		nestiobuf_done(bp, buf_len - issued_len, EINVAL);

	mutex_enter(&dmv->diskp_mtx);
	disk_unbusy(dmv->diskp, buf_len, bp ? (bp->b_flags & B_READ) : 0);
	mutex_exit(&dmv->diskp_mtx);

	dm_table_release(&dmv->table_head, DM_TABLE_ACTIVE);
	dm_dev_unbusy(dmv);
}


static int
dmread(dev_t dev, struct uio *uio, int flag)
{

	return physio(dmstrategy, NULL, dev, B_READ, dmminphys, uio);
}

static int
dmwrite(dev_t dev, struct uio *uio, int flag)
{

	return physio(dmstrategy, NULL, dev, B_WRITE, dmminphys, uio);
}

static int
dmsize(dev_t dev)
{
	dm_dev_t *dmv;
	uint64_t size;

	if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
		return -ENOENT;

	size = dm_table_size(&dmv->table_head);
	dm_dev_unbusy(dmv);

	return size;
}

static void
dmminphys(struct buf *bp)
{

	bp->b_bcount = MIN(bp->b_bcount, MAXPHYS);
}

void
dmgetproperties(struct disk *disk, dm_table_head_t *head)
{
	uint64_t numsec;
	unsigned int secsize;
	struct disk_geom *dg;

	dm_table_disksize(head, &numsec, &secsize);

	dg = &disk->dk_geom;

	memset(dg, 0, sizeof(*dg));
	dg->dg_secperunit = numsec;
	dg->dg_secsize = secsize;
	dg->dg_nsectors = 32;
	dg->dg_ntracks = 64;

	disk_set_info(NULL, disk, "ESDI");
}

/*
 * Transform char s to uint64_t offset number.
 */
uint64_t
atoi64(const char *s)
{
	uint64_t n;
	n = 0;

	while (*s != '\0') {
		if (!isdigit(*s))
			break;

		n = (10 * n) + (*s - '0');
		s++;
	}

	return n;
}