snapshot; dispatch list stuff

lib/dns/dispatchlist.c

@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2000  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#include <config.h>
+
+#include <stdlib.h>
+
+#include <isc/mem.h>
+#include <isc/util.h>
+
+#include <dns/dispatch.h>
+#include <dns/dispatchlist.h>
+#include <dns/types.h>
+
+/*
+ * This module implements a dispatch list.  The items on the list are
+ * dispatch objects.  These dispatchers have attributes such as shared,
+ * TCP, UDP, IPv4, IPv6, etc.  When searching for a usable shared
+ * dispatcher these flags are respected.
+ */
+
+typedef struct dns__dle dns__dle_t;
+
+struct dns__dle {
+	dns_dispatch_t	       *disp;
+	unsigned int		attributes;
+	ISC_LINK(dns__dle_t)	link;
+};
+
+struct dns_dispatchlist {
+	/* Unlocked. */
+	unsigned int		magic;
+	isc_mem_t	       *mctx;
+
+	/* Locked. */
+	isc_mutex_t		lock;
+	unsigned int		state;
+	ISC_LIST(dns__dle_t)	list;
+};
+
+#define SHUTTINGDOWN		0x00000001U
+#define IS_SHUTTINGDOWN(l)	(((l)->state & SHUTTINGDOWN) != 0)
+
+#define DNS_DISPATCHLIST_MAGIC		ISC_MAGIC('D', 'l', 's', 't')
+#define DNS_DISPATCHLIST_VALID(a) \
+	ISC_MAGIC_VALID(a, DNS_DISPATCHLIST_MAGIC)
+
+
+isc_result_t
+dns_dispatchlist_create(isc_mem_t *mctx, dns_dispatchlist_t **listp)
+{
+	dns_dispatchlist_t *list;
+	isc_result_t result;
+
+	REQUIRE(mctx != NULL);
+	REQUIRE(listp != NULL && *listp == NULL);
+
+	list = isc_mem_get(mctx, sizeof(dns_dispatchlist_t));
+	if (list == NULL)
+		return (ISC_R_NOMEMORY);
+
+	result = isc_mutex_init(&list->lock);
+	if (result != ISC_R_SUCCESS) {
+		isc_mem_put(mctx, list, sizeof(dns_dispatchlist_t));
+		return (result);
+	}
+
+	list->magic = DNS_DISPATCHLIST_MAGIC;
+	list->state = 0;
+	list->mctx = NULL;
+	isc_mem_attach(mctx, &list->mctx);
+	ISC_LIST_INIT(list->list);
+
+	*listp = list;
+	return (ISC_R_SUCCESS);
+}
+
+/*
+ * List must be locked when calling this function.
+ */
+static isc_boolean_t
+destroy_ok(dns_dispatchlist_t *list)
+{
+	if ((list->state & SHUTTINGDOWN) == 0)
+		return (ISC_FALSE);
+	if (!ISC_LIST_EMPTY(list->list))
+		return (ISC_FALSE);
+
+	return (ISC_TRUE);
+}
+
+/*
+ * List must be unlocked when calling this function.
+ */
+static void
+destroy(dns_dispatchlist_t **listp)
+{
+	isc_mem_t *mctx;
+	dns_dispatchlist_t *list;
+
+	list = *listp;
+	*listp = NULL;
+
+	mctx = list->mctx;
+
+	list->magic = 0;
+	list->mctx = 0;
+	isc_mutex_destroy(&list->lock);
+	list->state = 0;
+
+	isc_mem_put(mctx, list, sizeof(dns_dispatchlist_t));
+	isc_mem_detach(&mctx);
+}
+
+void
+dns_dispatchlist_destroy(dns_dispatchlist_t **listp)
+{
+	dns_dispatchlist_t *list;
+	isc_boolean_t killit;
+
+	REQUIRE(listp != NULL);
+	REQUIRE(DNS_DISPATCHLIST_VALID(*listp));
+	RUNTIME_CHECK(destory_ok(*listp));
+
+	list = *listp;
+	*listp = NULL;
+
+	LOCK(&list->lock);
+	list->state |= SHUTTINGDOWN;
+	killit = destroy_ok(list);
+	UNLOCK(&list->lock);
+
+	if (killit)
+		destroy(&list);
+}
+
+isc_result_t
+dns_dispatchlist_add(dns_dispatchlist_t *list, dns_dispatch_t *disp,
+		     unsigned int attributes)
+{
+	dns__dle_t *dle;
+	isc_result_t result;
+
+	REQUIRE(DNS_DISPATCHLIST_VALID(list));
+	REQUIRE(disp != NULL);
+
+	LOCK(&list->lock);
+	if (IS_SHUTTINGDOWN(list)) {
+		result = ISC_R_SHUTTINGDOWN;
+		goto out;
+	}
+
+	dle = isc_mem_get(list->mctx, sizeof(dns__dle_t));
+	if (dle == NULL) {
+		result = ISC_R_NOMEMORY;
+		goto out;
+	}
+
+	dle->disp = NULL;
+	dns_dispatch_attach(disp, &dle->disp);
+	dle->attributes = attributes;
+	ISC_LINK_INIT(dle, link);
+	ISC_LIST_APPEND(list->list, dle, link);
+
+	result = ISC_R_SUCCESS;
+
+ out:
+	UNLOCK(&list->lock);
+	return (result);
+}
+
+isc_result_t
+dns_dispatchlist_delete(dns_dispatchlist_t *list, dns_dispatch_t *disp)
+{
+	dns__dle_t *dle;
+	isc_result_t result;
+
+	dle = ISC_LIST_HEAD(list->list);
+	while (dle != NULL) {
+		if (dle->disp == disp)
+			break;
+		dle = ISC_LIST_NEXT(dle, link);
+	}
+
+	if (dle == NULL) {
+		result = ISC_R_NOTFOUND;
+		goto out;
+	}
+
+	ISC_LIST_UNLINK(list->list, dle, link);
+	dns_dispatch_detach(&dle->disp);
+	result = ISC_R_SUCCESS;
+
+ out:
+	killit = destroy_ok(list);
+	UNLOCK(&list->lock);
+	return (result);
+}
+
+isc_result_t
+dns_dispatchlist_find(dns_dispatchlist_t *list, unsigned int attributes,
+		      unsigned int mask, dns_dispatch_t **dispp)
+{
+}

lib/dns/include/dns/dispatchlist.h

@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2000  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#ifndef DNS_DISPATCHLIST_H
+#define DNS_DISPATCHLIST_H 1
+
+/*****
+ ***** Module Info
+ *****/
+
+/*
+ * DNS Dispatch List Management
+ *
+ * 	Maintains a list of dispatchers to help various parts of the DNS
+ *	library and applications keep track and share dispatchers.
+ *
+ * MP:
+ *
+ *     	All locking is performed internally to each list.
+ *
+ *	dns_dispatchlist_find() will return dispatches which are
+ *	attached.
+ *
+ * Reliability:
+ *
+ * Resources:
+ *
+ * Security:
+ *
+ *	None.
+ *
+ * Standards:
+ *
+ *	None.
+ */
+
+/***
+ *** Imports
+ ***/
+
+#include <isc/lang.h>
+
+#include <dns/types.h>
+
+/*
+ * Attributes for added dispatchers.
+ *
+ * Values with the mask 0xffff0000 are application defined.
+ * Values with the mask 0x0000ffff are library defined.
+ */
+#define DNS_DISPATCHLISTATTR_TCP	0x00000001U
+#define DNS_DISPATCHLISTATTR_UDP	0x00000002U
+#define DNS_DISPATCHLISTATTR_PRIVATE	0x00000004U
+
+ISC_LANG_BEGINDECLS
+
+isc_result_t
+dns_dispatchlist_create(isc_mem_t *mctx, dns_dispatchlist_t **listp);
+/*
+ * Creates a new dispatchlist object.
+ *
+ * Requires:
+ *	"mctx" be a valid memory context.
+ *
+ *	listp != NULL && *listp == NULL
+ *
+ * Returns:
+ *	ISC_R_SUCCESS	-- all ok
+ *
+ *	anythign else	-- failure
+ */
+
+
+void
+dns_dispatchlist_destroy(dns_dispatchlist_t **listp);
+/*
+ * Destroys the dispatchlist when it becomes empty.  This could be
+ * immediately.
+ *
+ * Requires:
+ *	listp != NULL && *listp is a valid dispatchlist.
+ */
+
+
+isc_result_t
+dns_dispatchlist_add(dns_dispatchlist_t *list, dns_dispatch_t *disp,
+		     unsigned int attributes);
+/*
+ * Add a new dispatch object to the dispatch list with the attributes
+ * supplied.
+ *
+ * Requires:
+ *	"list" be a valid dispatchlist.
+ *
+ *	"disp" be a valid dispatcher that is not already present on "list"
+ *
+ * Ensures:
+ *	On successful return, the dispatcher is attached, preventing it
+ *	from being deleted while on the dispatchlist.
+ *
+ * Returns:
+ *	ISC_R_SUCCESS	-- added.
+ *
+ *	anything else	-- failure.
+ */
+
+
+isc_result_t
+dns_dispatchlist_delete(dns_dispatchlist_t *list, dns_dispatch_t *disp);
+/*
+ * Deletes the dispatcher from the list.
+ *
+ * Requires:
+ *	"list" be a valid dispatchlist.
+ *
+ *	"disp" be a valid dispatcher.
+ *
+ * Ensures:
+ *	On successful return, the dispatcher is detached once, allowing it
+ *	to be deleted.
+ *
+ * Returns:
+ *	ISC_R_SUCCESS	-- deleted.
+ *
+ *	ISC_R_NOTFOUND	-- dispatcher is not on the list.
+ *
+ *	anything else	-- failure.
+ */
+
+
+isc_result_t
+dns_dispatchlist_find(dns_dispatchlist_t *list, unsigned int attributes,
+		      unsigned int mask, dns_dispatch_t **dispp);
+/*
+ * Search for a dispatcher that has the attributes specified by
+ *	(attributes & mask)
+ *
+ * Requires:
+ *	"list" be a valid dispatchlist.
+ *
+ *	dispp != NULL && *dispp == NULL.
+ *
+ * Ensures:
+ *	The dispatcher returned into *dispp is attached on behalf of the
+ *	caller.  It is required that the caller detach from it when it is
+ *	no longer needed.
+ *
+ * Returns:
+ *	ISC_R_SUCCESS	-- found.
+ *
+ *	ISC_R_NOTFOUND	-- no dispatcher matching the requirements found.
+ *
+ *	anything else	-- failure.
+ */
+
+
+ISC_LANG_ENDDECLS
+
+#endif /* DNS_DISPATCHLIST_H */