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cache: Provide safe versions of nl_cache_ops_associate() and nl_cache_ops_lookup()

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Signed-off-by: Thomas Graf <tgraf@suug.ch>
This commit is contained in:
Thomas Graf 2012-11-16 00:19:38 +01:00
parent 1a2c3e36a8
commit 2b3912a320
2 changed files with 78 additions and 18 deletions
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2
include/netlink/cache.h
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@ -106,7 +106,9 @@ extern void nl_cache_foreach_filter(struct nl_cache *,
/* Cache type management */
extern struct nl_cache_ops * nl_cache_ops_lookup(const char *);
extern struct nl_cache_ops * nl_cache_ops_lookup_safe(const char *);
extern struct nl_cache_ops * nl_cache_ops_associate(int, int);
extern struct nl_cache_ops * nl_cache_ops_associate_safe(int, int);
extern struct nl_msgtype * nl_msgtype_lookup(struct nl_cache_ops *, int);
extern void nl_cache_ops_foreach(void (*cb)(struct nl_cache_ops *, void *), void *);
extern int nl_cache_mngt_register(struct nl_cache_ops *);

94
lib/cache_mngt.c
View file

@ -68,11 +68,13 @@ void nl_cache_ops_put(struct nl_cache_ops *ops)
}
/**
* Lookup the set cache operations of a certain cache type
* Lookup cache operations by name
* @arg name name of the cache type
*
* @return The cache operations or NULL if no operations
* have been registered under the specified name.
* @attention This function is not safe, it does not increment the reference
* counter. Please use nl_cache_ops_lookup_safe().
*
* @return The cache operations or NULL if not found.
*/
struct nl_cache_ops *nl_cache_ops_lookup(const char *name)
{
@ -86,38 +88,91 @@ struct nl_cache_ops *nl_cache_ops_lookup(const char *name)
}
/**
* Associate a message type to a set of cache operations
* @arg protocol netlink protocol
* @arg msgtype netlink message type
* Lookup cache operations by name
* @arg name name of the cache type
*
* Associates the specified netlink message type with
* a registered set of cache operations.
* @note The reference counter of the returned cache operation is incremented
* and must be decremented after use with nl_cache_ops_put().
*
* @return The cache operations or NULL if no association
* could be made.
* @return The cache operations or NULL if not found.
*/
struct nl_cache_ops *nl_cache_ops_associate(int protocol, int msgtype)
struct nl_cache_ops *nl_cache_ops_lookup_safe(const char *name)
{
struct nl_cache_ops *ops;
nl_write_lock(&cache_ops_lock);
if ((ops = __nl_cache_ops_lookup(name)))
nl_cache_ops_get(ops);
nl_write_unlock(&cache_ops_lock);
return ops;
}
static struct nl_cache_ops *__cache_ops_associate(int protocol, int msgtype)
{
int i;
struct nl_cache_ops *ops;
nl_read_lock(&cache_ops_lock);
for (ops = cache_ops; ops; ops = ops->co_next) {
if (ops->co_protocol != protocol)
continue;
for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) {
if (ops->co_msgtypes[i].mt_id == msgtype) {
nl_read_unlock(&cache_ops_lock);
for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++)
if (ops->co_msgtypes[i].mt_id == msgtype)
return ops;
}
}
}
nl_read_unlock(&cache_ops_lock);
return NULL;
}
/**
* Associate protocol and message type to cache operations
* @arg protocol netlink protocol
* @arg msgtype netlink message type
*
* @attention This function is not safe, it does not increment the reference
* counter. Please use nl_cache_ops_associate_safe().
*
* @see nl_cache_ops_associate_safe()
*
* @return The cache operations or NULL if no match found.
*/
struct nl_cache_ops *nl_cache_ops_associate(int protocol, int msgtype)
{
struct nl_cache_ops *ops;
nl_read_lock(&cache_ops_lock);
ops = __cache_ops_associate(protocol, msgtype);
nl_read_unlock(&cache_ops_lock);
return ops;
}
/**
* Associate protocol and message type to cache operations
* @arg protocol netlink protocol
* @arg msgtype netlink message type
*
* Searches the registered cache operations for a matching protocol
* and message type.
*
* @note The reference counter of the returned cache operation is incremented
* and must be decremented after use with nl_cache_ops_put().
*
* @return The cache operations or NULL if no no match was found.
*/
struct nl_cache_ops *nl_cache_ops_associate_safe(int protocol, int msgtype)
{
struct nl_cache_ops *ops;
nl_write_lock(&cache_ops_lock);
if ((ops = __cache_ops_associate(protocol, msgtype)))
nl_cache_ops_get(ops);
nl_write_unlock(&cache_ops_lock);
return ops;
}
/**
* Lookup message type cache association
* @arg ops cache operations
@ -126,6 +181,9 @@ struct nl_cache_ops *nl_cache_ops_associate(int protocol, int msgtype)
* Searches for a matching message type association ing the specified
* cache operations.
*
* @attention The guranteed lifetime of the returned message type is bound
* to the lifetime of the underlying cache operations.
*
* @return A message type association or NULL.
*/
struct nl_msgtype *nl_msgtype_lookup(struct nl_cache_ops *ops, int msgtype)