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 "lttng-tracer-core.h"
  25 #include "jhash.h"
  26
  27 static CDS_LIST_HEAD(lttng_transport_list);
  28
  29 struct lttng_transport *lttng_transport_find(const char *name)
  30 {
  31         struct lttng_transport *transport;
  32
  33         cds_list_for_each_entry(transport, &lttng_transport_list, node) {
  34                 if (!strcmp(transport->name, name))
  35                         return transport;
  36         }
  37         return NULL;
  38 }
  39
  40 /**
  41  * lttng_transport_register - LTT transport registration
  42  * @transport: transport structure
  43  *
  44  * Registers a transport which can be used as output to extract the data out of
  45  * LTTng. Called with ust_lock held.
  46  */
  47 void lttng_transport_register(struct lttng_transport *transport)
  48 {
  49         cds_list_add_tail(&transport->node, &lttng_transport_list);
  50 }
  51
  52 /**
  53  * lttng_transport_unregister - LTT transport unregistration
  54  * @transport: transport structure
  55  * Called with ust_lock held.
  56  */
  57 void lttng_transport_unregister(struct lttng_transport *transport)
  58 {
  59         cds_list_del(&transport->node);
  60 }
  61
  62 /*
  63  * Needed by comm layer.
  64  */
  65 struct lttng_enum *lttng_ust_enum_get(struct lttng_session *session,
  66                 const char *enum_name)
  67 {
  68         struct lttng_enum *_enum;
  69         struct cds_hlist_head *head;
  70         struct cds_hlist_node *node;
  71         size_t name_len = strlen(enum_name);
  72         uint32_t hash;
  73
  74         hash = jhash(enum_name, name_len, 0);
  75         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
  76         cds_hlist_for_each_entry(_enum, node, head, hlist) {
  77                 assert(_enum->desc);
  78                 if (!strncmp(_enum->desc->name, enum_name,
  79                                 LTTNG_UST_SYM_NAME_LEN - 1))
  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 }