xref: /src/external/cddl/osnet/sys/kern/ddi.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1988 AT&T	*/
/*	All Rights Reserved */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <sys/types.h>
#include <sys/ddi.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/vfs_syscalls.h>

__strong_alias(ddi_strtol,ddi_strtoul)

/*
 * String to integer conversion routines.
 *
 * This file is derived from usr/src/common/util/strtol.c
 *
 * We cannot use the user land versions as there is no errno to report
 * error in kernel.  So the return value is used to return an error,
 * and the result is stored in an extra parameter passed by reference.
 * Otherwise, the following functions are identical to the user land
 * versions.
 */

/*
 * We should have a kernel version of ctype.h.
 */
#define	isalnum(ch)	(isalpha(ch) || isdigit(ch))
#define	isalpha(ch)	(isupper(ch) || islower(ch))
#define	isdigit(ch)	((ch) >= '0' && (ch) <= '9')
#define	islower(ch)	((ch) >= 'a' && (ch) <= 'z')
#define	isspace(ch)	(((ch) == ' ') || ((ch) == '\r') || ((ch) == '\n') || \
			((ch) == '\t') || ((ch) == '\f'))
#define	isupper(ch)	((ch) >= 'A' && (ch) <= 'Z')
#define	isxdigit(ch)	(isdigit(ch) || ((ch) >= 'a' && (ch) <= 'f') || \
			((ch) >= 'A' && (ch) <= 'F'))

#define	DIGIT(x)	\
	(isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')

#define	MBASE	('z' - 'a' + 1 + 10)

/*
 * The following macro is a local version of isalnum() which limits
 * alphabetic characters to the ranges a-z and A-Z; locale dependent
 * characters will not return 1. The members of a-z and A-Z are
 * assumed to be in ascending order and contiguous
 */
#define	lisalnum(x)	\
	(isdigit(x) || ((x) >= 'a' && (x) <= 'z') || ((x) >= 'A' && (x) <= 'Z'))

static int
do_mkdirp(const char *path)
{
	struct lwp *l = curlwp;
	int mode;
	int error;
	register_t ret;

	const char *s, *e;
	char *here;

	error = 0;
	mode = 493;

	if (*path != '/')
		panic("Not an absolute path");

	here = PNBUF_GET();
	for (s = path;; s = e) {
		e = strchr(s + 1, '/');
		if (e == NULL)
			break;

		strlcpy(here, path, e - path + 1);
		error = do_sys_mkdir(l, (const char *)here, mode, &ret, UIO_SYSSPACE);
	}
	PNBUF_PUT(here);

	if (error == EEXIST)
		error = 0;

	return error;
}

int
ddi_strtoul(const char *str, char **nptr, int base, unsigned long *result)
{
	unsigned long val;
	int c;
	int xx;
	unsigned long	multmax;
	int neg = 0;
	const char **ptr = (const char **)nptr;
	const unsigned char	*ustr = (const unsigned char *)str;

	if (ptr != (const char **)0)
		*ptr = (char *)ustr; /* in case no number is formed */
	if (base < 0 || base > MBASE || base == 1) {
		/* base is invalid -- should be a fatal error */
		return (EINVAL);
	}
	if (!isalnum(c = *ustr)) {
		while (isspace(c))
			c = *++ustr;
		switch (c) {
		case '-':
			neg++;
			/* FALLTHROUGH */
		case '+':
			c = *++ustr;
		}
	}
	if (base == 0)
		if (c != '0')
			base = 10;
		else if (ustr[1] == 'x' || ustr[1] == 'X')
			base = 16;
		else
			base = 8;
	/*
	 * for any base > 10, the digits incrementally following
	 *	9 are assumed to be "abc...z" or "ABC...Z"
	 */
	if (!lisalnum(c) || (xx = DIGIT(c)) >= base)
		return (EINVAL); /* no number formed */
	if (base == 16 && c == '0' && (ustr[1] == 'x' || ustr[1] == 'X') &&
	    isxdigit(ustr[2]))
		c = *(ustr += 2); /* skip over leading "0x" or "0X" */

	multmax = ULONG_MAX / (unsigned long)base;
	val = DIGIT(c);
	for (c = *++ustr; lisalnum(c) && (xx = DIGIT(c)) < base; ) {
		if (val > multmax)
			goto overflow;
		val *= base;
		if (ULONG_MAX - val < xx)
			goto overflow;
		val += xx;
		c = *++ustr;
	}
	if (ptr != (const char **)0)
		*ptr = (char *)ustr;
	*result = neg ? -val : val;
	return (0);

overflow:
	for (c = *++ustr; lisalnum(c) && (xx = DIGIT(c)) < base; (c = *++ustr))
		;
	if (ptr != (const char **)0)
		*ptr = (char *)ustr;
	return (ERANGE);
}

/*
 * Find first bit set in a mask (returned counting from 1 up)
 */

int
ddi_ffs(long mask)
{
	return (ffs(mask));
}

/*
 * Find last bit set. Take mask and clear
 * all but the most significant bit, and
 * then let ffs do the rest of the work.
 *
 * Algorithm courtesy of Steve Chessin.
 */

int
ddi_fls(long mask)
{
	while (mask) {
		long nx;

		if ((nx = (mask & (mask - 1))) == 0)
			break;
		mask = nx;
	}
	return (ffs(mask));
}

/*
 * The next five routines comprise generic storage management utilities
 * for driver soft state structures (in "the old days," this was done
 * with a statically sized array - big systems and dynamic loading
 * and unloading make heap allocation more attractive)
 */

/*
 * Allocate a set of pointers to 'n_items' objects of size 'size'
 * bytes.  Each pointer is initialized to nil.
 *
 * The 'size' and 'n_items' values are stashed in the opaque
 * handle returned to the caller.
 *
 * This implementation interprets 'set of pointers' to mean 'array
 * of pointers' but note that nothing in the interface definition
 * precludes an implementation that uses, for example, a linked list.
 * However there should be a small efficiency gain from using an array
 * at lookup time.
 *
 * NOTE	As an optimization, we make our growable array allocations in
 *	powers of two (bytes), since that's how much kmem_alloc (currently)
 *	gives us anyway.  It should save us some free/realloc's ..
 *
 *	As a further optimization, we make the growable array start out
 *	with MIN_N_ITEMS in it.
 */

/*
 * This data structure is entirely private to the soft state allocator.
 */
struct i_ddi_soft_state {
	void		**array;	/* the array of pointers */
	kmutex_t	lock;	/* serialize access to this struct */
	size_t		size;	/* how many bytes per state struct */
	size_t		n_items;	/* how many structs herein */
	struct i_ddi_soft_state *next;	/* 'dirty' elements */
};

#define	MIN_N_ITEMS	8	/* 8 void *'s == 32 bytes */

int
ddi_soft_state_init(void **state_p, size_t size, size_t n_items)
{
	struct i_ddi_soft_state *ss;

	if (state_p == NULL || *state_p != NULL || size == 0)
		return (EINVAL);

	ss = kmem_zalloc(sizeof (*ss), KM_SLEEP);
	mutex_init(&ss->lock, NULL, MUTEX_DRIVER, NULL);
	ss->size = size;

	if (n_items < MIN_N_ITEMS)
		ss->n_items = MIN_N_ITEMS;
	else {
		int bitlog;

		if ((bitlog = ddi_fls(n_items)) == ddi_ffs(n_items))
			bitlog--;
		ss->n_items = 1 << bitlog;
	}

	ASSERT(ss->n_items >= n_items);

	ss->array = kmem_zalloc(ss->n_items * sizeof (void *), KM_SLEEP);

	*state_p = ss;

	return (0);
}


/*
 * Allocate a state structure of size 'size' to be associated
 * with item 'item'.
 *
 * In this implementation, the array is extended to
 * allow the requested offset, if needed.
 */
int
ddi_soft_state_zalloc(void *state, int item)
{
	struct i_ddi_soft_state *ss;
	void **array;
	void *new_element;

	if ((ss = state) == NULL || item < 0)
		return (DDI_FAILURE);

	mutex_enter(&ss->lock);
	if (ss->size == 0) {
		mutex_exit(&ss->lock);
		cmn_err(CE_WARN, "ddi_soft_state_zalloc: bad handle");
		return (DDI_FAILURE);
	}

	array = ss->array;	/* NULL if ss->n_items == 0 */
	ASSERT(ss->n_items != 0 && array != NULL);

	/*
	 * refuse to tread on an existing element
	 */
	if (item < ss->n_items && array[item] != NULL) {
		mutex_exit(&ss->lock);
		return (DDI_FAILURE);
	}

	/*
	 * Allocate a new element to plug in
	 */
	new_element = kmem_zalloc(ss->size, KM_SLEEP);

	/*
	 * Check if the array is big enough, if not, grow it.
	 */
	if (item >= ss->n_items) {
		void	**new_array;
		size_t	new_n_items;
		struct i_ddi_soft_state *dirty;

		/*
		 * Allocate a new array of the right length, copy
		 * all the old pointers to the new array, then
		 * if it exists at all, put the old array on the
		 * dirty list.
		 *
		 * Note that we can't kmem_free() the old array.
		 *
		 * Why -- well the 'get' operation is 'mutex-free', so we
		 * can't easily catch a suspended thread that is just about
		 * to dereference the array we just grew out of.  So we
		 * cons up a header and put it on a list of 'dirty'
		 * pointer arrays.  (Dirty in the sense that there may
		 * be suspended threads somewhere that are in the middle
		 * of referencing them).  Fortunately, we -can- garbage
		 * collect it all at ddi_soft_state_fini time.
		 */
		new_n_items = ss->n_items;
		while (new_n_items < (1 + item))
			new_n_items <<= 1;	/* double array size .. */

		ASSERT(new_n_items >= (1 + item));	/* sanity check! */

		new_array = kmem_zalloc(new_n_items * sizeof (void *),
		    KM_SLEEP);
		/*
		 * Copy the pointers into the new array
		 */
		bcopy(array, new_array, ss->n_items * sizeof (void *));

		/*
		 * Save the old array on the dirty list
		 */
		dirty = kmem_zalloc(sizeof (*dirty), KM_SLEEP);
		dirty->array = ss->array;
		dirty->n_items = ss->n_items;
		dirty->next = ss->next;
		ss->next = dirty;

		ss->array = (array = new_array);
		ss->n_items = new_n_items;
	}

	ASSERT(array != NULL && item < ss->n_items && array[item] == NULL);

	array[item] = new_element;

	mutex_exit(&ss->lock);
	return (DDI_SUCCESS);
}


/*
 * Fetch a pointer to the allocated soft state structure.
 *
 * This is designed to be cheap.
 *
 * There's an argument that there should be more checking for
 * nil pointers and out of bounds on the array.. but we do a lot
 * of that in the alloc/free routines.
 *
 * An array has the convenience that we don't need to lock read-access
 * to it c.f. a linked list.  However our "expanding array" strategy
 * means that we should hold a readers lock on the i_ddi_soft_state
 * structure.
 *
 * However, from a performance viewpoint, we need to do it without
 * any locks at all -- this also makes it a leaf routine.  The algorithm
 * is 'lock-free' because we only discard the pointer arrays at
 * ddi_soft_state_fini() time.
 */
void *
ddi_get_soft_state(void *state, int item)
{
	struct i_ddi_soft_state *ss = state;

	ASSERT(ss != NULL && item >= 0);

	if (item < ss->n_items && ss->array != NULL)
		return (ss->array[item]);
	return (NULL);
}

/*
 * Free the state structure corresponding to 'item.'   Freeing an
 * element that has either gone or was never allocated is not
 * considered an error.  Note that we free the state structure, but
 * we don't shrink our pointer array, or discard 'dirty' arrays,
 * since even a few pointers don't really waste too much memory.
 *
 * Passing an item number that is out of bounds, or a null pointer will
 * provoke an error message.
 */
void
ddi_soft_state_free(void *state, int item)
{
	struct i_ddi_soft_state *ss;
	void **array;
	void *element;
	static char msg[] = "ddi_soft_state_free:";

	if ((ss = state) == NULL) {
		cmn_err(CE_WARN, "%s null handle",
		    msg);
		return;
	}

	element = NULL;

	mutex_enter(&ss->lock);

	if ((array = ss->array) == NULL || ss->size == 0) {
		cmn_err(CE_WARN, "%s bad handle",
		    msg);
	} else if (item < 0 || item >= ss->n_items) {
		cmn_err(CE_WARN, "%s item %d not in range [0..%lu]",
		    msg, item, ss->n_items - 1);
	} else if (array[item] != NULL) {
		element = array[item];
		array[item] = NULL;
	}

	mutex_exit(&ss->lock);

	if (element)
		kmem_free(element, ss->size);
}


/*
 * Free the entire set of pointers, and any
 * soft state structures contained therein.
 *
 * Note that we don't grab the ss->lock mutex, even though
 * we're inspecting the various fields of the data structure.
 *
 * There is an implicit assumption that this routine will
 * never run concurrently with any of the above on this
 * particular state structure i.e. by the time the driver
 * calls this routine, there should be no other threads
 * running in the driver.
 */
void
ddi_soft_state_fini(void **state_p)
{
	struct i_ddi_soft_state *ss, *dirty;
	int item;
	static char msg[] = "ddi_soft_state_fini:";

	if (state_p == NULL || (ss = *state_p) == NULL) {
		cmn_err(CE_WARN, "%s null handle",
		    msg);
		return;
	}

	if (ss->size == 0) {
		cmn_err(CE_WARN, "%s bad handle",
		    msg);
		return;
	}

	if (ss->n_items > 0) {
		for (item = 0; item < ss->n_items; item++)
			ddi_soft_state_free(ss, item);
		kmem_free(ss->array, ss->n_items * sizeof (void *));
	}

	/*
	 * Now delete any dirty arrays from previous 'grow' operations
	 */
	for (dirty = ss->next; dirty; dirty = ss->next) {
		ss->next = dirty->next;
		kmem_free(dirty->array, dirty->n_items * sizeof (void *));
		kmem_free(dirty, sizeof (*dirty));
	}

	mutex_destroy(&ss->lock);
	kmem_free(ss, sizeof (*ss));

	*state_p = NULL;
}

int
ddi_create_minor_node(dev_info_t *dip, char *name, int spec_type,
    minor_t minor_num, char *node_type, int flag)
{
	struct lwp *l = curlwp;
	char *pn;
	dev_t dev;
	int error;
	register_t ret;

	printf("ddi_create_minor_node: name %s\n", name);

	dev = makedev(flag, minor_num);

	pn = PNBUF_GET();
	if (spec_type == S_IFCHR)
		snprintf(pn, MAXPATHLEN, "/dev/zvol/rdsk/%s", name);
	else
		snprintf(pn, MAXPATHLEN, "/dev/zvol/dsk/%s", name);

	if ((error = do_mkdirp(pn)) != 0)
		goto exit;

	error = do_sys_mknod(l, (const char *)pn, spec_type, dev, &ret, UIO_SYSSPACE);

exit:
	PNBUF_PUT(pn);

	return error;
}

void
ddi_remove_minor_node(dev_info_t *dip, char *name)
{
	char *pn;
	int error;

	pn = PNBUF_GET();
	snprintf(pn, MAXPATHLEN, "/dev/zvol/dsk/%s", name);
	(void)do_sys_unlink(pn, UIO_SYSSPACE);
	PNBUF_PUT(pn);

	/* We need to remove raw and block device nodes */
	pn = PNBUF_GET();
	snprintf(pn, MAXPATHLEN, "/dev/zvol/rdsk/%s", name);
	(void)do_sys_unlink(pn, UIO_SYSSPACE);
	PNBUF_PUT(pn);
}