liblttng-ust/ust-core.c

   1 /*
   2  * ust-core.c
   3  *
   4  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; only
   9  * version 2.1 of the License.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <stdlib.h>
  22 #include <lttng/ust-events.h>
  23 #include <usterr-signal-safe.h>
  24 #include "jhash.h"
  25
  26 static CDS_LIST_HEAD(lttng_transport_list);
  27
  28 struct lttng_transport *lttng_transport_find(const char *name)
  29 {
  30         struct lttng_transport *transport;
  31
  32         cds_list_for_each_entry(transport, &lttng_transport_list, node) {
  33                 if (!strcmp(transport->name, name))
  34                         return transport;
  35         }
  36         return NULL;
  37 }
  38
  39 /**
  40  * lttng_transport_register - LTT transport registration
  41  * @transport: transport structure
  42  *
  43  * Registers a transport which can be used as output to extract the data out of
  44  * LTTng. Called with ust_lock held.
  45  */
  46 void lttng_transport_register(struct lttng_transport *transport)
  47 {
  48         cds_list_add_tail(&transport->node, &lttng_transport_list);
  49 }
  50
  51 /**
  52  * lttng_transport_unregister - LTT transport unregistration
  53  * @transport: transport structure
  54  * Called with ust_lock held.
  55  */
  56 void lttng_transport_unregister(struct lttng_transport *transport)
  57 {
  58         cds_list_del(&transport->node);
  59 }
  60
  61 /*
  62  * Needed by comm layer.
  63  */
  64 struct lttng_enum *lttng_ust_enum_get(struct lttng_session *session,
  65                 const char *enum_name)
  66 {
  67         struct lttng_enum *_enum;
  68         struct cds_hlist_head *head;
  69         struct cds_hlist_node *node;
  70         size_t name_len = strlen(enum_name);
  71         uint32_t hash;
  72
  73         hash = jhash(enum_name, name_len, 0);
  74         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
  75         cds_hlist_for_each_entry(_enum, node, head, hlist) {
  76                 assert(_enum->desc);
  77                 if (!strncmp(_enum->desc->name, enum_name,
  78                                 LTTNG_UST_SYM_NAME_LEN - 1))
  79                         return _enum;
  80         }
  81         return NULL;
  82 }