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)

diff --git a/include/netlink-types.h b/include/netlink-types.h
index 5ced83698d1a0b4a28409a7b06784b4e7b109000..24228a7b1e27da35213c13e82ef2019edd5208e2 100644 (file)
--- 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 59886ac32fdc025c72bb3fb9b9ad56a88794216e..e42f6924a5232d2a63d2309e24ff51496062ab7f 100644 (file)
--- 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 b6e4a82d5e94c3844e76fbf0324b66fff83348fd..f4960d6561e5cd7aa72128d5aca254538db4ab20 100644 (file)
--- 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) {