sem.c

早期freebsd实现

/* 
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * All advertising materials mentioning features or use of this software
 * must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Lawrence Berkeley Laboratories.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	@(#)sem.c	8.1 (Berkeley) 6/6/93
 */

#include <sys/param.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "sem.h"

/*
 * config semantics.
 */

#define	NAMESIZE	100	/* local name buffers */

static const char *s_generic;
static const char *s_qmark;

static struct hashtab *attrtab;		/* for attribute lookup */
static struct hashtab *cfhashtab;	/* for config lookup */
static struct hashtab *devitab;		/* etc */

static struct attr errattr;
static struct devbase errdev;
static struct devbase **nextbase;
static struct config **nextcf;
static struct devi **nextdevi;
static struct devi **nextpseudo;

static int has_errobj __P((struct nvlist *, void *));
static struct nvlist *addtoattr __P((struct nvlist *, struct devbase *));
static int exclude __P((struct nvlist *, const char *, const char *));
static int resolve __P((struct nvlist **, const char *, const char *,
			struct nvlist *, int));
static int lresolve __P((struct nvlist **, const char *, const char *,
			struct nvlist *, int));
static struct devi *newdevi __P((const char *, int, struct devbase *d));
static struct devi *getdevi __P((const char *));
static const char *concat __P((const char *, int));
static int split __P((const char *, size_t, char *, size_t, int *));
static void selectbase __P((struct devbase *));
static int onlist __P((struct nvlist *, void *));
static const char **fixloc __P((const char *, struct attr *, struct nvlist *));

void
initsem()
{

	attrtab = ht_new();
	errattr.a_name = "<internal>";

	allbases = NULL;
	nextbase = &allbases;

	cfhashtab = ht_new();
	allcf = NULL;
	nextcf = &allcf;

	devitab = ht_new();
	alldevi = NULL;
	nextdevi = &alldevi;
	errdev.d_name = "<internal>";

	allpseudo = NULL;
	nextpseudo = &allpseudo;

	s_generic = intern("generic");
	s_qmark = intern("?");
}

void
enddefs(fname)
	const char *fname;
{
	register struct devbase *dev;

	for (dev = allbases; dev != NULL; dev = dev->d_next) {
		if (!dev->d_isdef) {
			(void)fprintf(stderr,
			    "%s: device `%s' used but not defined\n",
			    fname, dev->d_name);
			errors++;
			continue;
		}
	}
	if (errors) {
		(void)fprintf(stderr, "*** Stop.\n");
		exit(1);
	}
}

void
setdefmaxusers(min, def, max)
	int min, def, max;
{

	if (min < 1 || min > def || def > max)
		error("maxusers must have 1 <= min <= default <= max");
	else {
		minmaxusers = min;
		defmaxusers = def;
		maxmaxusers = max;
	}
}

void
setmaxusers(n)
	int n;
{

	if (maxusers != 0) {
		error("duplicate maxusers parameter");
		return;
	}
	maxusers = n;
	if (n < minmaxusers) {
		error("warning: minimum of %d maxusers assumed\n", minmaxusers);
		errors--;	/* take it away */
		maxusers = minmaxusers;
	} else if (n > maxmaxusers) {
		error("warning: maxusers (%d) > %d", n, maxmaxusers);
		errors--;
	}
}

/*
 * Define an attribute, optionally with an interface (a locator list).
 * Since an empty locator list is logically different from "no interface",
 * all locator lists include a dummy head node, which we discard here.
 */
int
defattr(name, locs)
	const char *name;
	struct nvlist *locs;
{
	register struct attr *a;
	register struct nvlist *nv;
	register int len;

	a = emalloc(sizeof *a);
	if (ht_insert(attrtab, name, a)) {
		free(a);
		error("attribute `%s' already defined", name);
		nvfreel(locs);
		return (1);
	}
	a->a_name = name;
	if (locs != NULL) {
		a->a_iattr = 1;
		a->a_locs = locs->nv_next;
		nvfree(locs);
	} else {
		a->a_iattr = 0;
		a->a_locs = NULL;
	}
	len = 0;
	for (nv = a->a_locs; nv != NULL; nv = nv->nv_next)
		len++;
	a->a_loclen = len;
	a->a_devs = NULL;
	a->a_refs = NULL;
	return (0);
}

/*
 * Return true if the given `error object' is embedded in the given
 * pointer list.
 */
static int
has_errobj(nv, obj)
	register struct nvlist *nv;
	register void *obj;
{

	for (; nv != NULL; nv = nv->nv_next)
		if (nv->nv_ptr == obj)
			return (1);
	return (0);
}

/*
 * Add a device base to a list in an attribute (actually, to any list).
 * Note that this does not check for duplicates, and does reverse the
 * list order, but no one cares anyway.
 */
static struct nvlist *
addtoattr(l, dev)
	register struct nvlist *l;
	register struct devbase *dev;
{
	register struct nvlist *n;

	n = newnv(NULL, NULL, dev, 0);
	n->nv_next = l;
	return (n);
}

/*
 * Device a device, giving its allowable parent attachments, if any.
 * This may (or may not) also define an interface attribute and/or refer
 * to existing attributes.  There may be a list of vectors.
 */
void
defdev(dev, ispseudo, atlist, vectors, loclist, attrs)
	register struct devbase *dev;
	int ispseudo;
	struct nvlist *atlist, *vectors, *loclist, *attrs;
{
	register struct nvlist *nv;
	register struct attr *a;

	if (dev == &errdev)
		goto bad;
	if (dev->d_isdef) {
		error("redefinition of `%s'", dev->d_name);
		goto bad;
	}
	dev->d_isdef = 1;
	if (has_errobj(attrs, &errattr))
		goto bad;

	/*
	 * Handle implicit attribute definition from locator list.  Do
	 * this before scanning the `at' list so that we can have, e.g.:
	 *	device foo at other, foo { slot = -1 }
	 * (where you can plug in a foo-bus extender to a foo-bus).
	 */
	if (loclist != NULL) {
		nv = loclist;
		loclist = NULL;	/* defattr disposes of them for us */
		if (defattr(dev->d_name, nv))
			goto bad;
		nv = newnv(dev->d_name, NULL, getattr(dev->d_name), 0);
		nv->nv_next = attrs;
		attrs = nv;
	}

	/* Committed!  Set up fields. */
	dev->d_ispseudo = ispseudo;
	dev->d_atlist = atlist;
	dev->d_vectors = vectors;
	dev->d_attrs = attrs;

	/*
	 * Turn the `at' list into interface attributes (map each
	 * nv_name to an attribute, or to NULL for root), and add
	 * this device to those attributes, so that children can
	 * be listed at this particular device if they are supported
	 * by that attribute.
	 */
	for (nv = atlist; nv != NULL; nv = nv->nv_next) {
		if (nv->nv_name == NULL) {
			nv->nv_ptr = NULL;	/* at root */
			continue;
		}
		nv->nv_ptr = a = getattr(nv->nv_name);
		if (a == &errattr)
			continue;		/* already complained */
		if (!a->a_iattr)
			error("%s cannot be at plain attribute `%s'",
			    dev->d_name, a->a_name);
		else
			a->a_devs = addtoattr(a->a_devs, dev);
	}

	/*
	 * For each interface attribute this device refers to, add this
	 * device to its reference list.  This makes, e.g., finding all
	 * "scsi"s easier.
	 */
	for (nv = attrs; nv != NULL; nv = nv->nv_next) {
		a = nv->nv_ptr;
		if (a->a_iattr)
			a->a_refs = addtoattr(a->a_refs, dev);
	}
	return;
bad:
	nvfreel(atlist);
	nvfreel(vectors);
	nvfreel(loclist);
	nvfreel(attrs);
}

/*
 * Look up a devbase.  Also makes sure it is a reasonable name,
 * i.e., does not end in a digit or contain special characters.
 */
struct devbase *
getdevbase(name)
	const char *name;
{
	register u_char *p;
	register struct devbase *dev;

	p = (u_char *)name;
	if (!isalpha(*p))
		goto badname;
	while (*++p) {
		if (!isalnum(*p) && *p != '_')
			goto badname;
	}
	if (isdigit(*--p)) {
badname:
		error("bad device base name `%s'", name);
		return (&errdev);
	}
	dev = ht_lookup(devbasetab, name);
	if (dev == NULL) {
		dev = emalloc(sizeof *dev);
		dev->d_name = name;
		dev->d_next = NULL;
		dev->d_isdef = 0;
		dev->d_major = NODEV;
		dev->d_atlist = NULL;
		dev->d_vectors = NULL;
		dev->d_attrs = NULL;
		dev->d_ihead = NULL;
		dev->d_ipp = &dev->d_ihead;
		dev->d_umax = 0;
		*nextbase = dev;
		nextbase = &dev->d_next;
		if (ht_insert(devbasetab, name, dev))
			panic("getdevbase(%s)", name);
	}
	return (dev);
}

/*
 * Look up an attribute.
 */
struct attr *
getattr(name)
	const char *name;
{
	struct attr *a;

	if ((a = ht_lookup(attrtab, name)) == NULL) {
		error("undefined attribute `%s'", name);
		a = &errattr;
	}
	return (a);
}

/*
 * Set the major device number for a device, so that it can be used
 * as a root/swap/dumps "on" device in a configuration.
 */
void
setmajor(d, n)
	struct devbase *d;
	int n;
{

	if (d != &errdev && d->d_major != NODEV)
		error("device `%s' is already major %d",
		    d->d_name, d->d_major);
	else
		d->d_major = n;
}

#define ABS(x) ((x) < 0 ? -(x) : (x))

static int
exclude(nv, name, what)
	struct nvlist *nv;
	const char *name, *what;
{

	if (nv != NULL) {
		error("%s: swap generic must not specify %s", name, what);
		return (1);
	}
	return (0);
}

/* 
 * Map things like "ra0b" => makedev(major("ra"), 0*8 + 'b'-'a').
 * Handle the case where the device number is given but there is no
 * corresponding name, and map NULL to the default.
 */
static int
resolve(nvp, name, what, dflt, part)
	register struct nvlist **nvp;
	const char *name, *what;
	struct nvlist *dflt;
	register int part;
{
	register struct nvlist *nv;
	register struct devbase *dev;
	register const char *cp;
	register int maj, min, l;
	int unit;
	char buf[NAMESIZE];

	if ((u_int)(part -= 'a') >= 7)
		panic("resolve");
	if ((nv = *nvp) == NULL) {
		/*
		 * Apply default.  Easiest to do this by number.
		 */
		maj = major(dflt->nv_int);
		min = (minor(dflt->nv_int) & ~7) | part;
		*nvp = nv = newnv(NULL, NULL, NULL, makedev(maj, min));
	}
	if (nv->nv_int != NODEV) {
		/*
		 * By the numbers.  Find the appropriate major number
		 * to make a name.
		 */
		maj = major(nv->nv_int);
		min = minor(nv->nv_int);
		for (dev = allbases; dev != NULL; dev = dev->d_next)
			if (dev->d_major == maj)
				break;
		if (dev == NULL)
			(void)sprintf(buf, "<%d/%d>", maj, min);
		else
			(void)sprintf(buf, "%s%d%c", dev->d_name,
			    min >> 3, (min & 7) + 'a');
		nv->nv_str = intern(buf);
		return (0);
	}

	/*
	 * The normal case: things like "ra2b".  Check for partition
	 * suffix, remove it if there, and split into name ("ra") and
	 * unit (2).
	 */
	l = strlen(nv->nv_str);
	cp = &nv->nv_str[l];
	if (l > 1 && *--cp >= 'a' && *cp <= 'h' && isdigit(cp[-1])) {
		l--;
		part = *cp - 'a';
	}
	cp = nv->nv_str;
	if (split(cp, l, buf, sizeof buf, &unit)) {
		error("%s: invalid %s device name `%s'", name, what, cp);
		return (1);
	}
	dev = ht_lookup(devbasetab, intern(buf));
	if (dev == NULL || dev->d_major == NODEV) {
		error("%s: can't make %s device from `%s'",
		    name, what, nv->nv_str);
		return (1);
	}