sem.c

早期freebsd实现

	nv->nv_name = dev->d_name;
	nv->nv_int = makedev(dev->d_major, unit * 8 + part);
	return (0);
}

static int
lresolve(nvp, name, what, dflt, part)
	register struct nvlist **nvp;
	const char *name, *what;
	struct nvlist *dflt;
	int part;
{
	int err;

	while ((err = resolve(nvp, name, what, dflt, part)) == 0 &&
	    (*nvp)->nv_next != NULL)
		nvp = &(*nvp)->nv_next;
	return (err);
}

/*
 * Add a completed configuration to the list.
 */
void
addconf(cf0)
	register struct config *cf0;
{
	register struct config *cf;
	register struct nvlist *nv;
	const char *name;

	name = cf0->cf_name;
	cf = emalloc(sizeof *cf);
	if (ht_insert(cfhashtab, name, cf)) {
		error("configuration `%s' already defined", name);
		free(cf);
		goto bad;
	}
	*cf = *cf0;

	/*
	 * Look for "swap generic".
	 */
	for (nv = cf->cf_swap; nv != NULL; nv = nv->nv_next)
		if (nv->nv_str == s_generic)
			break;
	if (nv != NULL) {
		/*
		 * Make sure no root or dump device specified, and no
		 * other swap devices.  Note single | here (check all).
		 */
		nv = cf->cf_swap;
		if (exclude(cf->cf_root, name, "root device") |
		    exclude(nv->nv_next, name, "additional swap devices") |
		    exclude(cf->cf_dump, name, "dump device"))
			goto bad;
	} else {
		nv = cf->cf_root;
		if (nv == NULL) {
			error("%s: no root device specified", name);
			goto bad;
		}
		if (resolve(&cf->cf_root, name, "root", nv, 'a') |
		    lresolve(&cf->cf_swap, name, "swap", nv, 'b') |
		    resolve(&cf->cf_dump, name, "dumps", nv, 'b'))
			goto bad;
	}
	*nextcf = cf;
	nextcf = &cf->cf_next;
	return;
bad:
	nvfreel(cf0->cf_root);
	nvfreel(cf0->cf_swap);
	nvfreel(cf0->cf_dump);
}

void
setconf(npp, what, v)
	register struct nvlist **npp;
	const char *what;
	struct nvlist *v;
{

	if (*npp != NULL) {
		error("duplicate %s specification", what);
		nvfreel(v);
	} else
		*npp = v;
}

static struct devi *
newdevi(name, unit, d)
	const char *name;
	int unit;
	struct devbase *d;
{
	register struct devi *i;

	i = emalloc(sizeof *i);
	i->i_name = name;
	i->i_unit = unit;
	i->i_base = d;
	i->i_next = NULL;
	i->i_bsame = NULL;
	i->i_alias = NULL;
	i->i_at = NULL;
	i->i_atattr = NULL;
	i->i_atdev = NULL;
	i->i_locs = NULL;
	i->i_cfflags = 0;
	i->i_lineno = currentline();
	if (unit >= d->d_umax)
		d->d_umax = unit + 1;
	return (i);
}

/*
 * Add the named device as attaching to the named attribute (or perhaps
 * another device instead) plus unit number.
 */
void
adddev(name, at, loclist, flags)
	const char *name, *at;
	struct nvlist *loclist;
	int flags;
{
	register struct devi *i;	/* the new instance */
	register struct attr *attr;	/* attribute that allows attach */
	register struct devbase *ib;	/* i->i_base */
	register struct devbase *ab;	/* not NULL => at another dev */
	register struct nvlist *nv;
	const char *cp;
	int atunit;
	char atbuf[NAMESIZE];

	ab = NULL;
	if (at == NULL) {
		/* "at root" */
		if ((i = getdevi(name)) == NULL)
			goto bad;
		/*
		 * Must warn about i_unit > 0 later, after taking care of
		 * the STAR cases (we could do non-star's here but why
		 * bother?).  Make sure this device can be at root.
		 */
		ib = i->i_base;
		if (!onlist(ib->d_atlist, NULL)) {
			error("%s's cannot attach to the root", ib->d_name);
			goto bad;
		}
		attr = &errattr;	/* a convenient "empty" attr */
	} else {
		if (split(at, strlen(at), atbuf, sizeof atbuf, &atunit)) {
			error("invalid attachment name `%s'", at);
			/* (void)getdevi(name); -- ??? */
			goto bad;
		}
		if ((i = getdevi(name)) == NULL)
			goto bad;
		ib = i->i_base;
		cp = intern(atbuf);
		if ((attr = ht_lookup(attrtab, cp)) == NULL) {
			/*
			 * Have to work a bit harder to see whether we have
			 * something like "tg0 at esp0" (where esp is merely
			 * not an attribute) or "tg0 at nonesuch0" (where
			 * nonesuch is not even a device).
			 */
			if ((ab = ht_lookup(devbasetab, cp)) == NULL) {
				error("%s at %s: `%s' unknown",
				    name, at, atbuf);
				goto bad;
			}
			/*
			 * See if the named parent carries an attribute
			 * that allows it to supervise device ib.
			 */
			for (nv = ab->d_attrs; nv != NULL; nv = nv->nv_next) {
				attr = nv->nv_ptr;
				if (onlist(attr->a_devs, ib))
					goto ok;
			}
			attr = &errattr;/* now onlist below will fail */
		}
		if (!onlist(attr->a_devs, ib)) {
			error("%s's cannot attach to %s's", ib->d_name, atbuf);
			goto bad;
		}
	}
ok:
	if ((i->i_locs = fixloc(name, attr, loclist)) == NULL)
		goto bad;
	if (i->i_unit == STAR && ib->d_vectors != NULL) {
		error("%s's cannot be *'d as they have preset vectors",
		    ib->d_name);
		goto bad;
	}
	i->i_at = at;
	i->i_atattr = attr;
	i->i_atdev = ab;
	i->i_atunit = atunit;
	i->i_cfflags = flags;
	selectbase(ib);
	/* all done, fall into ... */
bad:
	nvfreel(loclist);
	return;
}

void
addpseudo(name, number)
	const char *name;
	int number;
{
	register struct devbase *d;
	register struct devi *i;

	d = ht_lookup(devbasetab, name);
	if (d == NULL) {
		error("undefined pseudo-device %s", name);
		return;
	}
	if (!d->d_ispseudo) {
		error("%s is a real device, not a pseudo-device", name);
		return;
	}
	if (ht_lookup(devitab, name) != NULL) {
		error("`%s' already defined", name);
		return;
	}
	i = newdevi(name, number - 1, d);	/* foo 16 => "foo0..foo15" */
	if (ht_insert(devitab, name, i))
		panic("addpseudo(%s)", name);
	selectbase(d);
	*nextpseudo = i;
	nextpseudo = &i->i_next;
	npseudo++;
}

/*
 * Define a new instance of a specific device.
 */
static struct devi *
getdevi(name)
	const char *name;
{
	register struct devi *i, *firsti;
	register struct devbase *d;
	int unit;
	char base[NAMESIZE];

	if (split(name, strlen(name), base, sizeof base, &unit)) {
		error("invalid device name `%s'", name);
		return (NULL);
	}
	d = ht_lookup(devbasetab, intern(base));
	if (d == NULL) {
		error("%s: unknown device `%s'", name, base);
		return (NULL);
	}
	if (d->d_ispseudo) {
		error("%s: %s is a pseudo-device", name, base);
		return (NULL);
	}
	firsti = ht_lookup(devitab, name);
	i = newdevi(name, unit, d);
	if (firsti == NULL) {
		if (ht_insert(devitab, name, i))
			panic("getdevi(%s)", name);
		*d->d_ipp = i;
		d->d_ipp = &i->i_bsame;
	} else {
		while (firsti->i_alias)
			firsti = firsti->i_alias;
		firsti->i_alias = i;
	}
	*nextdevi = i;
	nextdevi = &i->i_next;
	ndevi++;
	return (i);
}

static const char *
concat(name, c)
	const char *name;
	int c;
{
	register int len;
	char buf[NAMESIZE];

	len = strlen(name);
	if (len + 2 > sizeof(buf)) {
		error("device name `%s%c' too long", name, c);
		len = sizeof(buf) - 2;
	}
	bcopy(name, buf, len);
	buf[len] = c;
	buf[len + 1] = 0;
	return (intern(buf));
}

const char *
starref(name)
	const char *name;
{

	return (concat(name, '*'));
}

const char *
wildref(name)
	const char *name;
{

	return (concat(name, '?'));
}

/*
 * Split a name like "foo0" into base name (foo) and unit number (0).
 * Return 0 on success.  To make this useful for names like "foo0a",
 * the length of the "foo0" part is one of the arguments.
 */
static int
split(name, nlen, base, bsize, aunit)
	register const char *name;
	size_t nlen;
	char *base;
	size_t bsize;
	int *aunit;
{
	register const char *cp;
	register int c, l;

	l = nlen;
	if (l < 2 || l >= bsize || isdigit(*name))
		return (1);
	c = (u_char)name[--l];
	if (!isdigit(c)) {
		if (c == '*')
			*aunit = STAR;
		else if (c == '?')
			*aunit = WILD;
		else
			return (1);
	} else {
		cp = &name[l];
		while (isdigit(cp[-1]))
			l--, cp--;
		*aunit = atoi(cp);
	}
	bcopy(name, base, l);
	base[l] = 0;
	return (0);
}

/*
 * We have an instance of the base foo, so select it and all its
 * attributes for "optional foo".
 */
static void
selectbase(d)
	register struct devbase *d;
{
	register struct attr *a;
	register struct nvlist *nv;

	(void)ht_insert(selecttab, d->d_name, (char *)d->d_name);
	for (nv = d->d_attrs; nv != NULL; nv = nv->nv_next) {
		a = nv->nv_ptr;
		(void)ht_insert(selecttab, a->a_name, (char *)a->a_name);
	}
}

/*
 * Is the given pointer on the given list of pointers?
 */
static int
onlist(nv, ptr)
	register struct nvlist *nv;
	register void *ptr;
{
	for (; nv != NULL; nv = nv->nv_next)
		if (nv->nv_ptr == ptr)
			return (1);
	return (0);
}

static char *
extend(p, name)
	register char *p;
	const char *name;
{
	register int l;

	l = strlen(name);
	bcopy(name, p, l);
	p += l;
	*p++ = ',';
	*p++ = ' ';
	return (p);
}

/*
 * Check that we got all required locators, and default any that are
 * given as "?" and have defaults.  Return 0 on success.
 */
static const char **
fixloc(name, attr, got)
	const char *name;
	register struct attr *attr;
	register struct nvlist *got;
{
	register struct nvlist *m, *n;
	register int ord;
	register const char **lp;
	int nmissing, nextra, nnodefault;
	char *mp, *ep, *ndp;
	char missing[1000], extra[1000], nodefault[1000];
	static const char *nullvec[1];

	/*
	 * Look for all required locators, and number the given ones
	 * according to the required order.  While we are numbering,
	 * set default values for defaulted locators.
	 */
	if (attr->a_loclen == 0)	/* e.g., "at root" */
		lp = nullvec;
	else
		lp = emalloc((attr->a_loclen + 1) * sizeof(const char *));
	for (n = got; n != NULL; n = n->nv_next)
		n->nv_int = -1;
	nmissing = 0;
	mp = missing;
	/* yes, this is O(mn), but m and n should be small */
	for (ord = 0, m = attr->a_locs; m != NULL; m = m->nv_next, ord++) {
		for (n = got; n != NULL; n = n->nv_next) {
			if (n->nv_name == m->nv_name) {
				n->nv_int = ord;
				break;
			}
		}
		if (n == NULL && m->nv_int == 0) {
			nmissing++;
			mp = extend(mp, m->nv_name);
		}
		lp[ord] = m->nv_str;
	}
	if (ord != attr->a_loclen)
		panic("fixloc");
	lp[ord] = NULL;
	nextra = 0;
	ep = extra;
	nnodefault = 0;
	ndp = nodefault;
	for (n = got; n != NULL; n = n->nv_next) {
		if (n->nv_int >= 0) {
			if (n->nv_str != NULL)
				lp[n->nv_int] = n->nv_str;
			else if (lp[n->nv_int] == NULL) {
				nnodefault++;
				ndp = extend(ndp, n->nv_name);
			}
		} else {
			nextra++;
			ep = extend(ep, n->nv_name);
		}
	}
	if (nextra) {
		ep[-2] = 0;	/* kill ", " */
		error("%s: extraneous locator%s: %s",
		    name, nextra > 1 ? "s" : "", extra);
	}
	if (nmissing) {
		mp[-2] = 0;
		error("%s: must specify %s", name, missing);
	}
	if (nnodefault) {
		ndp[-2] = 0;
		error("%s: cannot wildcard %s", name, nodefault);
	}
	if (nmissing || nnodefault) {
		free(lp);
		lp = NULL;
	}
	return (lp);
}