cache_mngr: Automatically allocate socket if needed

The requirement to have the caller provide the socket does not
make much sense. Automatically allocate the socket if none was
provided.

This may also avoid some future abuse of reusing request sockets
for handling notifications.

Also rename cm_handle to cm_sock for clarity (no API change)

3 files changed, 57 insertions, 25 deletions

diff --git a/include/netlink-types.h b/include/netlink-types.h
index 5ced836..24228a7 100644
--- a/include/netlink-types.h
+++ b/include/netlink-types.h
@@ -6,7 +6,7 @@
  *	License as published by the Free Software Foundation version 2.1
  *	of the License.
  *
- * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
+ * Copyright (c) 2003-2012 Thomas Graf <tgraf@suug.ch>
  */
 
 #ifndef NETLINK_LOCAL_TYPES_H_
@@ -92,7 +92,7 @@ struct nl_cache_mngr
 	int			cm_protocol;
 	int			cm_flags;
 	int			cm_nassocs;
-	struct nl_sock *	cm_handle;
+	struct nl_sock *	cm_sock;
 	struct nl_cache_assoc *	cm_assocs;
 };
 
diff --git a/include/netlink/cache.h b/include/netlink/cache.h
index 59886ac..e42f692 100644
--- a/include/netlink/cache.h
+++ b/include/netlink/cache.h
@@ -6,7 +6,7 @@
  *	License as published by the Free Software Foundation version 2.1
  *	of the License.
  *
- * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
+ * Copyright (c) 2003-2012 Thomas Graf <tgraf@suug.ch>
  */
 
 #ifndef NETLINK_CACHE_H_
@@ -113,6 +113,7 @@ extern struct nl_cache *	__nl_cache_mngt_require(const char *);
 struct nl_cache_mngr;
 
 #define NL_AUTO_PROVIDE		1
+#define NL_ALLOCATED_SOCK	2  /* For internal use only, do not use */
 
 extern int			nl_cache_mngr_alloc(struct nl_sock *,
 						    int, int,
diff --git a/lib/cache_mngr.c b/lib/cache_mngr.c
index b6e4a82..f4960d6 100644
--- a/lib/cache_mngr.c
+++ b/lib/cache_mngr.c
@@ -6,7 +6,7 @@
  *	License as published by the Free Software Foundation version 2.1
  *	of the License.
  *
- * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
+ * Copyright (c) 2003-2012 Thomas Graf <tgraf@suug.ch>
  */
 
 /**
@@ -82,11 +82,30 @@ found:
 
 /**
  * Allocate new cache manager
- * @arg sk		Netlink socket.
- * @arg protocol	Netlink Protocol this manager is used for
- * @arg flags		Flags
+ * @arg sk		Netlink socket or NULL to auto allocate
+ * @arg protocol	Netlink protocol this manager is used for
+ * @arg flags		Flags (\c NL_AUTO_PROVIDE)
  * @arg result		Result pointer
  *
+ * Allocates a new cache manager for the specified netlink protocol.
+ *
+ * 1. If sk is not specified (\c NULL) a netlink socket matching the
+ *    specified protocol will be automatically allocated.
+ *
+ * 2. The socket will be put in non-blocking mode and sequence checking
+ *    will be disabled regardless of whether the socket was provided by
+ *    the caller or automatically allocated.
+ *
+ * 3. The socket will be connected.
+ *
+ * If the flag \c NL_AUTO_PROVIDE is specified, any cache added to the
+ * manager will automatically be made available to other users using
+ * nl_cache_mngt_provide().
+ *
+ * @note If the socket is provided by the caller, it is NOT recommended
+ *       to use the socket for anything else besides receiving netlink
+ *       notifications.
+ *
  * @return 0 on success or a negative error code.
  */
 int nl_cache_mngr_alloc(struct nl_sock *sk, int protocol, int flags,
@@ -95,14 +114,22 @@ int nl_cache_mngr_alloc(struct nl_sock *sk, int protocol, int flags,
 	struct nl_cache_mngr *mngr;
 	int err = -NLE_NOMEM;
 
-	if (sk == NULL)
+	/* Catch abuse of flags */
+	if (flags & NL_ALLOCATED_SOCK)
 		BUG();
 
 	mngr = calloc(1, sizeof(*mngr));
 	if (!mngr)
-		goto errout;
+		return -NLE_NOMEM;
+
+	if (!sk) {
+		if (!(sk = nl_socket_alloc()))
+			goto errout;
 
-	mngr->cm_handle = sk;
+		flags |= NL_ALLOCATED_SOCK;
+	}
+
+	mngr->cm_sock = sk;
 	mngr->cm_nassocs = 32;
 	mngr->cm_protocol = protocol;
 	mngr->cm_flags = flags;
@@ -112,12 +139,12 @@ int nl_cache_mngr_alloc(struct nl_sock *sk, int protocol, int flags,
 		goto errout;
 
 	/* Required to receive async event notifications */
-	nl_socket_disable_seq_check(mngr->cm_handle);
+	nl_socket_disable_seq_check(mngr->cm_sock);
 
-	if ((err = nl_connect(mngr->cm_handle, protocol) < 0))
+	if ((err = nl_connect(mngr->cm_sock, protocol) < 0))
 		goto errout;
 
-	if ((err = nl_socket_set_nonblocking(mngr->cm_handle) < 0))
+	if ((err = nl_socket_set_nonblocking(mngr->cm_sock) < 0))
 		goto errout;
 
 	NL_DBG(1, "Allocated cache manager %p, protocol %d, %d caches\n",
@@ -142,7 +169,7 @@ errout:
  * Allocates a new cache of the specified type and adds it to the manager.
  * The operation will trigger a full dump request from the kernel to
  * initially fill the contents of the cache. The manager will subscribe
- * to the notification group of the cache to keep track of any further
+ * to the notification group of the cache and keep track of any further
  * changes.
  *
  * @return 0 on success or a negative error code.
@@ -199,12 +226,12 @@ retry:
 		return -NLE_NOMEM;
 
 	for (grp = ops->co_groups; grp->ag_group; grp++) {
-		err = nl_socket_add_membership(mngr->cm_handle, grp->ag_group);
+		err = nl_socket_add_membership(mngr->cm_sock, grp->ag_group);
 		if (err < 0)
 			goto errout_free_cache;
 	}
 
-	err = nl_cache_refill(mngr->cm_handle, cache);
+	err = nl_cache_refill(mngr->cm_sock, cache);
 	if (err < 0)
 		goto errout_drop_membership;
 
@@ -223,7 +250,7 @@ retry:
 
 errout_drop_membership:
 	for (grp = ops->co_groups; grp->ag_group; grp++)
-		nl_socket_drop_membership(mngr->cm_handle, grp->ag_group);
+		nl_socket_drop_membership(mngr->cm_sock, grp->ag_group);
 errout_free_cache:
 	nl_cache_free(cache);
 
@@ -240,7 +267,7 @@ errout_free_cache:
  */
 int nl_cache_mngr_get_fd(struct nl_cache_mngr *mngr)
 {
-	return nl_socket_get_fd(mngr->cm_handle);
+	return nl_socket_get_fd(mngr->cm_sock);
 }
 
 /**
@@ -262,7 +289,7 @@ int nl_cache_mngr_poll(struct nl_cache_mngr *mngr, int timeout)
 {
 	int ret;
 	struct pollfd fds = {
-		.fd = nl_socket_get_fd(mngr->cm_handle),
+		.fd = nl_socket_get_fd(mngr->cm_sock),
 		.events = POLLIN,
 	};
 
@@ -272,6 +299,7 @@ int nl_cache_mngr_poll(struct nl_cache_mngr *mngr, int timeout)
 	if (ret < 0)
 		return -nl_syserr2nlerr(errno);
 
+	/* No events, return */
 	if (ret == 0)
 		return 0;
 
@@ -295,15 +323,15 @@ int nl_cache_mngr_data_ready(struct nl_cache_mngr *mngr)
 	struct nl_cb *cb;
 
 	NL_DBG(2, "Cache manager %p, reading new data from fd %d\n",
-	       mngr, nl_socket_get_fd(mngr->cm_handle));
+	       mngr, nl_socket_get_fd(mngr->cm_sock));
 
-	cb = nl_cb_clone(mngr->cm_handle->s_cb);
+	cb = nl_cb_clone(mngr->cm_sock->s_cb);
 	if (cb == NULL)
 		return -NLE_NOMEM;
 
 	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, event_input, mngr);
 
-	err = nl_recvmsgs(mngr->cm_handle, cb);
+	err = nl_recvmsgs(mngr->cm_sock, cb);
 	nl_cb_put(cb);
 	if (err < 0)
 		return err;
@@ -315,7 +343,7 @@ int nl_cache_mngr_data_ready(struct nl_cache_mngr *mngr)
  * Free cache manager and all caches.
  * @arg mngr		Cache manager.
  *
- * Release all resources after usage of a cache manager.
+ * Release all resources held by a cache manager.
  */
 void nl_cache_mngr_free(struct nl_cache_mngr *mngr)
 {
@@ -324,8 +352,11 @@ void nl_cache_mngr_free(struct nl_cache_mngr *mngr)
 	if (!mngr)
 		return;
 
-	if (mngr->cm_handle)
-		nl_close(mngr->cm_handle);
+	if (mngr->cm_sock)
+		nl_close(mngr->cm_sock);
+
+	if (mngr->cm_flags & NL_ALLOCATED_SOCK)
+		nl_socket_free(mngr->cm_sock);
 
 	for (i = 0; i < mngr->cm_nassocs; i++) {
 		if (mngr->cm_assocs[i].ca_cache) {