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 #define _LGPL_SOURCE
  22 #include <stdlib.h>
  23 #include <lttng/ust-events.h>
  24 #include <usterr-signal-safe.h>
  25 #include "lttng-tracer-core.h"
  26 #include "jhash.h"
  27
  28 static CDS_LIST_HEAD(lttng_transport_list);
  29
  30 struct lttng_transport *lttng_transport_find(const char *name)
  31 {
  32         struct lttng_transport *transport;
  33
  34         cds_list_for_each_entry(transport, &lttng_transport_list, node) {
  35                 if (!strcmp(transport->name, name))
  36                         return transport;
  37         }
  38         return NULL;
  39 }
  40
  41 /**
  42  * lttng_transport_register - LTT transport registration
  43  * @transport: transport structure
  44  *
  45  * Registers a transport which can be used as output to extract the data out of
  46  * LTTng. Called with ust_lock held.
  47  */
  48 void lttng_transport_register(struct lttng_transport *transport)
  49 {
  50         cds_list_add_tail(&transport->node, &lttng_transport_list);
  51 }
  52
  53 /**
  54  * lttng_transport_unregister - LTT transport unregistration
  55  * @transport: transport structure
  56  * Called with ust_lock held.
  57  */
  58 void lttng_transport_unregister(struct lttng_transport *transport)
  59 {
  60         cds_list_del(&transport->node);
  61 }
  62
  63 /*
  64  * Needed by comm layer.
  65  */
  66 struct lttng_enum *lttng_ust_enum_get_from_desc(struct lttng_session *session,
  67                 const struct lttng_enum_desc *enum_desc)
  68 {
  69         struct lttng_enum *_enum;
  70         struct cds_hlist_head *head;
  71         struct cds_hlist_node *node;
  72         size_t name_len = strlen(enum_desc->name);
  73         uint32_t hash;
  74
  75         hash = jhash(enum_desc->name, name_len, 0);
  76         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
  77         cds_hlist_for_each_entry(_enum, node, head, hlist) {
  78                 assert(_enum->desc);
  79                 if (_enum->desc == enum_desc)
  80                         return _enum;
  81         }
  82         return NULL;
  83 }
  84
  85 size_t lttng_ust_dummy_get_size(struct lttng_ctx_field *field, size_t offset)
  86 {
  87         size_t size = 0;
  88
  89         size += lib_ring_buffer_align(offset, lttng_alignof(char));
  90         size += sizeof(char);           /* tag */
  91         return size;
  92 }
  93
  94 void lttng_ust_dummy_record(struct lttng_ctx_field *field,
  95                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
  96                  struct lttng_channel *chan)
  97 {
  98         char sel_char = (char) LTTNG_UST_DYNAMIC_TYPE_NONE;
  99
 100         lib_ring_buffer_align_ctx(ctx, lttng_alignof(sel_char));
 101         chan->ops->event_write(ctx, &sel_char, sizeof(sel_char));
 102 }
 103
 104 void lttng_ust_dummy_get_value(struct lttng_ctx_field *field,
 105                 struct lttng_ctx_value *value)
 106 {
 107         value->sel = LTTNG_UST_DYNAMIC_TYPE_NONE;
 108 }
 109
 110 int lttng_context_is_app(const char *name)
 111 {
 112         if (strncmp(name, "$app.", strlen("$app.")) != 0) {
 113                 return 0;
 114         }
 115         return 1;
 116 }