X-Git-Url: http://git.onelab.eu/?p=libnl.git;a=blobdiff_plain;f=lib%2Fcache.c;fp=lib%2Fcache.c;h=9b88c7ccc5aec9f7b404599bf052011e8bb5990a;hp=0000000000000000000000000000000000000000;hb=4cee2ecb3b8afa0637e6f5fe4c57985a4bc740ff;hpb=2df2fbe518d5a221ce6e3ee88a3fb23fb1b94b27

diff --git a/lib/cache.c b/lib/cache.c
new file mode 100644
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--- /dev/null
+++ b/lib/cache.c
@@ -0,0 +1,551 @@
+/*
+ * lib/cache.c		Caching Module
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
+ */
+
+/**
+ * @ingroup utils
+ * @defgroup cache Caching
+ *
+ * @code
+ *   Cache Management             |    | Type Specific Cache Operations
+ *                                      
+ *                                |    | +----------------+ +------------+
+ *                                       | request update | | msg_parser |
+ *                                |    | +----------------+ +------------+
+ *                                     +- - - - -^- - - - - - - -^- -|- - - -
+ *    nl_cache_update:            |              |               |   |
+ *          1) --------- co_request_update ------+               |   |
+ *                                |                              |   |
+ *          2) destroy old cache     +----------- pp_cb ---------|---+
+ *                                |  |                           |
+ *          3) ---------- nl_recvmsgs ----------+   +- cb_valid -+
+ *             +--------------+   |  |          |   |
+ *             | nl_cache_add |<-----+   + - - -v- -|- - - - - - - - - - -
+ *             +--------------+   |      | +-------------+
+ *                                         | nl_recvmsgs |
+ *                                |      | +-----|-^-----+
+ *                                           +---v-|---+
+ *                                |      |   | nl_recv |
+ *                                           +---------+
+ *                                |      |                 Core Netlink
+ * @endcode
+ * 
+ * @{
+ */
+
+#include <netlink-local.h>
+#include <netlink/netlink.h>
+#include <netlink/cache.h>
+#include <netlink/object.h>
+#include <netlink/utils.h>
+
+static inline char *nl_cache_name(struct nl_cache *cache)
+{
+	return cache->c_ops ? cache->c_ops->co_name : "unknown";
+}
+
+/**
+ * @name Access Functions
+ * @{
+ */
+
+/**
+ * Return the number of items in the cache
+ * @arg cache		cache handle
+ */
+int nl_cache_nitems(struct nl_cache *cache)
+{
+	return cache->c_nitems;
+}
+
+/**
+ * Return the number of items matching a filter in the cache
+ * @arg cache		Cache object.
+ * @arg filter		Filter object.
+ */
+int nl_cache_nitems_filter(struct nl_cache *cache, struct nl_object *filter)
+{
+	struct nl_cache_ops *ops = cache->c_ops;
+	struct nl_object *obj;
+	int nitems = 0;
+	
+	nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
+		if (filter && ops->co_filter && !ops->co_filter(obj, filter))
+			continue;
+
+		nitems++;
+	}
+
+	return nitems;
+}
+
+/**
+ * Returns \b true if the cache is empty.
+ * @arg cache		Cache to check
+ * @return \a true if the cache is empty, otherwise \b false is returned.
+ */
+int nl_cache_is_empty(struct nl_cache *cache)
+{
+	return nl_list_empty(&cache->c_items);
+}
+
+/**
+ * Return the operations set of the cache
+ * @arg cache		cache handle
+ */
+struct nl_cache_ops *nl_cache_get_ops(struct nl_cache *cache)
+{
+	return cache->c_ops;
+}
+
+/**
+ * Return the first element in the cache
+ * @arg cache		cache handle
+ */
+struct nl_object *nl_cache_get_first(struct nl_cache *cache)
+{
+	if (nl_list_empty(&cache->c_items))
+		return NULL;
+
+	return nl_list_entry(cache->c_items.next,
+			     struct nl_object, ce_list);
+}
+
+/**
+ * Return the last element in the cache
+ * @arg cache		cache handle
+ */
+struct nl_object *nl_cache_get_last(struct nl_cache *cache)
+{
+	if (nl_list_empty(&cache->c_items))
+		return NULL;
+
+	return nl_list_entry(cache->c_items.prev,
+			     struct nl_object, ce_list);
+}
+
+/**
+ * Return the next element in the cache
+ * @arg obj		current object
+ */
+struct nl_object *nl_cache_get_next(struct nl_object *obj)
+{
+	if (nl_list_at_tail(obj, &obj->ce_cache->c_items, ce_list))
+		return NULL;
+	else
+		return nl_list_entry(obj->ce_list.next,
+				     struct nl_object, ce_list);
+}
+
+/**
+ * Return the previous element in the cache
+ * @arg obj		current object
+ */
+struct nl_object *nl_cache_get_prev(struct nl_object *obj)
+{
+	if (nl_list_at_head(obj, &obj->ce_cache->c_items, ce_list))
+		return NULL;
+	else
+		return nl_list_entry(obj->ce_list.prev,
+				     struct nl_object, ce_list);
+}
+
+/** @} */
+
+/**
+ * @name Cache Creation/Deletion
+ * @{
+ */
+
+/**
+ * Allocate an empty cache of no certain type
+ * 
+ * @return A newly allocated and initialized cache.
+ */
+struct nl_cache *nl_cache_alloc(void)
+{
+	struct nl_cache *cache;
+
+	cache = calloc(1, sizeof(*cache));
+	if (!cache) {
+		nl_errno(ENOMEM);
+		return NULL;
+	}
+
+	nl_init_list_head(&cache->c_items);
+	NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache));
+
+	return cache;
+}
+
+/**
+ * Allocate an empty cache based on cache operations
+ * @arg ops		cache operations to base the cache on
+ * @return A newly allocated and initialized cache.
+ */
+struct nl_cache *nl_cache_alloc_from_ops(struct nl_cache_ops *ops)
+{
+	struct nl_cache *new;
+
+	new = nl_cache_alloc();
+	if (!new)
+		return NULL;
+
+	new->c_ops = ops;
+
+	return new;
+}
+
+/**
+ * Allocate an empty cache based on type name
+ * @arg kind		Name of cache type
+ * @return A newly allocated and initialized cache.
+ */
+struct nl_cache *nl_cache_alloc_name(const char *kind)
+{
+	struct nl_cache_ops *ops;
+
+	ops = nl_cache_mngt_lookup(kind);
+	if (!ops) {
+		nl_error(ENOENT, "Unable to lookup cache \"%s\"", kind);
+		return NULL;
+	}
+
+	return nl_cache_alloc_from_ops(ops);
+}
+
+/**
+ * Clear a cache.
+ * @arg cache		cache to clear
+ *
+ * Removes all elements of a cache.
+ */
+void nl_cache_clear(struct nl_cache *cache)
+{
+	struct nl_object *obj, *tmp;
+
+	NL_DBG(1, "Clearing cache %p <%s>...\n", cache, nl_cache_name(cache));
+
+	nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list)
+		nl_cache_delete(cache, obj);
+}
+
+/**
+ * Free a cache.
+ * @arg cache		Cache to free.
+ *
+ * Removes all elements of a cache and frees all memory.
+ *
+ * @note Use this function if you are working with allocated caches.
+ */
+void nl_cache_free(struct nl_cache *cache)
+{
+	nl_cache_clear(cache);
+	NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
+	free(cache);
+}
+
+/** @} */
+
+/**
+ * @name Cache Modifications
+ * @{
+ */
+
+/**
+ * Add an element to the cache.
+ * @arg cache		cache to add a element to
+ * @arg obj		Common obj to be added to the cache
+ *
+ * Adds the object \c obj to the tail of the cache \c cache and. The
+ * cache is enlarged as needed.
+ *
+ * @return 0 or a negative error code.
+ */
+int nl_cache_add(struct nl_cache *cache, struct nl_object *obj)
+{
+	struct nl_object *new;
+
+	if (nl_object_shared(obj)) {
+		new = nl_object_clone(obj);
+		if (!new)
+			return nl_errno(ENOMEM);
+
+		nl_object_put(obj);
+	} else
+		new = obj;
+
+	new->ce_cache = cache;
+
+	nl_list_add_tail(&new->ce_list, &cache->c_items);
+	cache->c_nitems++;
+
+	NL_DBG(1, "Added %p to cache %p <%s>.\n",
+	       new, cache, nl_cache_name(cache));
+
+	return 0;
+}
+
+static int subsys_parse_cb(struct nl_object *c, struct nl_parser_param *p)
+{
+	return nl_cache_add((struct nl_cache *) p->pp_arg, c);
+}
+
+/** @cond SKIP */
+int nl_cache_parse(struct nl_cache_ops *ops, struct sockaddr_nl *who,
+		   struct nlmsghdr *nlh, struct nl_parser_param *params)
+{
+	int i, len, err, hdrsize;
+
+	hdrsize = ops->co_hdrsize;
+	len = nlh->nlmsg_len - nlmsg_msg_size(hdrsize);
+	if (len < 0) {
+		err = nl_error(EINVAL, "netlink message too short to "
+				       "of kind %s", ops->co_name);
+		goto errout;
+	}
+
+	for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
+		if (ops->co_msgtypes[i].mt_id == nlh->nlmsg_type)
+			return ops->co_msg_parser(who, nlh, params);
+
+	err = nl_error(EINVAL, "Unsupported netlink message type %d",
+		       nlh->nlmsg_type);
+errout:
+	return err;
+}
+/** @endcond */
+
+/**
+ * Parse a netlink message and add it to the cache.
+ * @arg cache		cache to add element to
+ * @arg msg		netlink message
+ *
+ * Parses a netlink message by calling the cache specific message parser
+ * and adds the new element to the cache.
+ *
+ * @return 0 or a negative error code.
+ */
+int nl_cache_parse_and_add(struct nl_cache *cache, struct nl_msg *msg)
+{
+	struct nl_parser_param p = {
+		.pp_cb = subsys_parse_cb,
+		.pp_arg = cache,
+	};
+
+	return nl_cache_parse(cache->c_ops, NULL, nlmsg_hdr(msg), &p);
+}
+
+/**
+ * Delete an element from a cache.
+ * @arg cache		cache to delete the element from
+ * @arg obj		Object to delete
+ *
+ * Deletes the object \c obj from the cache \c cache.
+ */
+void nl_cache_delete(struct nl_cache *cache, struct nl_object *obj)
+{
+	if (obj->ce_cache != cache)
+		BUG();
+
+	nl_list_del(&obj->ce_list);
+	obj->ce_cache = NULL;
+	nl_object_put(obj);
+	cache->c_nitems--;
+
+	NL_DBG(1, "Deleted %p from cache %p <%s>.\n",
+	       obj, cache, nl_cache_name(cache));
+}
+
+/** @cond SKIP */
+struct update_xdata {
+	struct nl_cache_ops *ops;
+	struct nl_parser_param *params;
+};
+/** @endcond */
+
+static int update_msg_parser(struct nl_msg *msg, void *arg)
+{
+	struct update_xdata *x = arg;
+	
+	return nl_cache_parse(x->ops, &msg->nm_src, msg->nm_nlh, x->params);
+}
+
+/**
+ * Pickup a netlink dump response and put it into a cache.
+ * @arg handle		Netlink handle.
+ * @arg cache		Cache to put items into.
+ *
+ * Waits for netlink messages to arrive, parses them and puts them into
+ * the specified cache.
+ *
+ * @return 0 on success or a negative error code.
+ */
+int nl_cache_pickup(struct nl_handle *handle, struct nl_cache *cache)
+{
+	int err;
+	struct nl_cache_ops *ops = cache->c_ops;
+	struct nl_cb *cb;
+	struct nl_parser_param p = {
+		.pp_cb = subsys_parse_cb,
+		.pp_arg = cache,
+	};
+	struct update_xdata x = {
+		.ops = ops,
+		.params = &p,
+	};
+
+	NL_DBG(1, "Filling cache %p <%s>...\n", cache, nl_cache_name(cache));
+
+	cb = nl_cb_clone(nl_handle_get_cb(handle));
+	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x);
+
+	err = nl_recvmsgs(handle, cb);
+	if (err < 0)
+		NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned " \
+		       "%d: %s", cache, nl_cache_name(cache),
+		       err, nl_geterror());
+
+	nl_cb_destroy(cb);
+
+	return err;
+}
+
+/**
+ * Update (synchronize) a local cache with the kernel.
+ * @arg handle		netlink handle
+ * @arg cache		cache to update
+ *
+ * Updates the local cache \c cache with the state in the kernel. During
+ * this process the cache gets emptied and refilled with the new content
+ * received from the kernel.
+ *
+ * @return 0 or a negative error code.
+ */
+int nl_cache_update(struct nl_handle *handle, struct nl_cache *cache)
+{
+	int err;
+	struct nl_cache_ops *ops = cache->c_ops;
+
+	err = ops->co_request_update(cache, handle);
+	if (err < 0)
+		return err;
+
+	NL_DBG(2, "Upading cache %p <%s>, request sent, waiting for dump...\n",
+	       cache, nl_cache_name(cache));
+	nl_cache_clear(cache);
+
+	return nl_cache_pickup(handle, cache);
+}
+
+/** @} */
+
+/**
+ * @name Dumping
+ * @{
+ */
+
+/**
+ * Dump all elements of a cache.
+ * @arg cache		cache to dump
+ * @arg params		dumping parameters
+ *
+ * Dumps all elements of the \a cache to the file descriptor \a fd.
+ */
+void nl_cache_dump(struct nl_cache *cache, struct nl_dump_params *params)
+{
+	NL_DBG(1, "Dumping cache %p <%s>\n", cache, nl_cache_name(cache));
+	nl_cache_dump_filter(cache, params, NULL);
+}
+
+/**
+ * Dump all elements of a cache (filtered).
+ * @arg cache		cache to dump
+ * @arg params		dumping parameters (optional)
+ * @arg filter		filter object
+ *
+ * Dumps all elements of the \a cache to the file descriptor \a fd
+ * given they match the given filter \a filter.
+ */
+void nl_cache_dump_filter(struct nl_cache *cache,
+			  struct nl_dump_params *params,
+			  struct nl_object *filter)
+{
+	int type = params ? params->dp_type : NL_DUMP_FULL;
+	struct nl_cache_ops *ops = cache->c_ops;
+	struct nl_object *obj;
+
+	if (type > NL_DUMP_MAX || type < 0)
+		BUG();
+
+	if (!ops->co_dump[type])
+		return;
+
+	nl_list_for_each_entry(obj, &cache->c_items, ce_list) {
+		if (filter && obj->ce_ops != filter->ce_ops)
+			continue;
+		
+		if (filter && ops->co_filter && !ops->co_filter(obj, filter))
+			continue;
+
+		dump_from_ops(obj, params);
+	}
+}
+
+/** @} */
+
+/**
+ * @name Iterators
+ * @{
+ */
+
+/**
+ * Call a callback on each element of the cache.
+ * @arg cache		cache to iterate on
+ * @arg cb		callback function
+ * @arg arg		argument passed to callback function
+ *
+ * Calls a callback function \a cb on each element of the \a cache.
+ * The argument \a arg is passed on the callback function.
+ */
+void nl_cache_foreach(struct nl_cache *cache,
+		      void (*cb)(struct nl_object *, void *), void *arg)
+{
+	nl_cache_foreach_filter(cache, NULL, cb, arg);
+}
+
+/**
+ * Call a callback on each element of the cache (filtered).
+ * @arg cache		cache to iterate on
+ * @arg filter		filter object
+ * @arg cb		callback function
+ * @arg arg		argument passed to callback function
+ *
+ * Calls a callback function \a cb on each element of the \a cache
+ * that matches the \a filter. The argument \a arg is passed on
+ * to the callback function.
+ */
+void nl_cache_foreach_filter(struct nl_cache *cache, struct nl_object *filter,
+			     void (*cb)(struct nl_object *, void *), void *arg)
+{
+	struct nl_object *obj, *tmp;
+	struct nl_cache_ops *ops = cache->c_ops;
+
+	nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list) {
+		if (filter && ops->co_filter && !ops->co_filter(obj, filter))
+			continue;
+
+		cb(obj, arg);
+	}
+}
+
+/** @} */
+
+/** @} */