int
mdeg_unregister(mdeg_handle_t hdl)
{
mdeg_clnt_t *clnt;
mdeg_handle_t mdh;
/* should never be called from a callback */
ASSERT(!taskq_member(mdeg.taskq, curthread));
rw_enter(&mdeg.rwlock, RW_WRITER);
/* lookup the client */
if ((clnt = mdeg_get_client(hdl)) == NULL) {
rw_exit(&mdeg.rwlock);
return (MDEG_FAILURE);
}
MDEG_DBG("client unregistered (0x%lx):\n", hdl);
MDEG_DUMP_CLNT(clnt);
/* save the handle to prevent reuse */
mdh = clnt->hdl;
bzero(clnt, sizeof (mdeg_clnt_t));
clnt->hdl = mdh;
mdeg.nclnts--;
rw_exit(&mdeg.rwlock);
return (MDEG_SUCCESS);
}
/*
* Register to receive an event notification when the system
* machine description is updated.
*
* Passing NULL for the node specification parameter is valid
* as long as the match specification is also NULL. In this
* case, the client will receive a notification when the MD
* has been updated, but the callback will not include any
* information. The client is then responsible for obtaining
* its own copy of the system MD and performing any processing
* manually.
*/
int
mdeg_register(mdeg_node_spec_t *pspecp, mdeg_node_match_t *nmatchp,
mdeg_cb_t cb, void *cb_arg, mdeg_handle_t *hdlp)
{
mdeg_clnt_t *clnt;
/*
* If the RW lock is held, a client is calling
* register from its own callback.
*/
if (RW_LOCK_HELD(&mdeg.rwlock)) {
MDEG_DBG("mdeg_register: rwlock already held\n");
return (MDEG_FAILURE);
}
/* node spec and node match must both be valid, or both NULL */
if (((pspecp != NULL) && (nmatchp == NULL)) ||
((pspecp == NULL) && (nmatchp != NULL))) {
MDEG_DBG("mdeg_register: invalid parameters\n");
return (MDEG_FAILURE);
}
rw_enter(&mdeg.rwlock, RW_WRITER);
clnt = mdeg_alloc_clnt();
ASSERT(clnt);
/*
* Fill in the rest of the data
*/
clnt->nmatch = nmatchp;
clnt->pspec = pspecp;
clnt->cb = cb;
clnt->cb_arg = cb_arg;
clnt->magic = MDEG_MAGIC;
/* do this last */
clnt->valid = B_TRUE;
MDEG_DBG("client registered (0x%lx):\n", clnt->hdl);
MDEG_DUMP_CLNT(clnt);
mdeg.nclnts++;
if (mdeg_notify_client_reg(clnt) != MDEG_SUCCESS) {
bzero(clnt, sizeof (mdeg_clnt_t));
rw_exit(&mdeg.rwlock);
return (MDEG_FAILURE);
}
rw_exit(&mdeg.rwlock);
*hdlp = clnt->hdl;
return (MDEG_SUCCESS);
}
int
mdeg_unregister(mdeg_handle_t hdl)
{
mdeg_clnt_t *clnt;
mdeg_handle_t mdh;
/*
* If the RW lock is held, a client is calling
* unregister from its own callback.
*/
if (RW_LOCK_HELD(&mdeg.rwlock)) {
MDEG_DBG("mdeg_unregister: rwlock already held\n");
return (MDEG_FAILURE);
}
/* lookup the client */
if ((clnt = mdeg_get_client(hdl)) == NULL) {
return (MDEG_FAILURE);
}
rw_enter(&mdeg.rwlock, RW_WRITER);
MDEG_DBG("client unregistered (0x%lx):\n", hdl);
MDEG_DUMP_CLNT(clnt);
/* save the handle to prevent reuse */
mdh = clnt->hdl;
bzero(clnt, sizeof (mdeg_clnt_t));
clnt->hdl = mdh;
mdeg.nclnts--;
rw_exit(&mdeg.rwlock);
return (MDEG_SUCCESS);
}
