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 <stdint.h>
  23 #include <stddef.h>
  24 #include <stdlib.h>
  25 #include <lttng/ust-events.h>
  26 #include <usterr-signal-safe.h>
  27 #include "lttng-tracer-core.h"
  28 #include "jhash.h"
  29
  30 static CDS_LIST_HEAD(lttng_transport_list);
  31 static CDS_LIST_HEAD(lttng_counter_transport_list);
  32
  33 struct lttng_transport *lttng_transport_find(const char *name)
  34 {
  35         struct lttng_transport *transport;
  36
  37         cds_list_for_each_entry(transport, &lttng_transport_list, node) {
  38                 if (!strcmp(transport->name, name))
  39                         return transport;
  40         }
  41         return NULL;
  42 }
  43
  44 struct lttng_counter_transport *lttng_counter_transport_find(const char *name)
  45 {
  46         struct lttng_counter_transport *transport;
  47
  48         cds_list_for_each_entry(transport, &lttng_counter_transport_list, node) {
  49                 if (!strcmp(transport->name, name))
  50                         return transport;
  51         }
  52         return NULL;
  53 }
  54
  55 /**
  56  * lttng_transport_register - LTT transport registration
  57  * @transport: transport structure
  58  *
  59  * Registers a transport which can be used as output to extract the data out of
  60  * LTTng. Called with ust_lock held.
  61  */
  62 void lttng_transport_register(struct lttng_transport *transport)
  63 {
  64         cds_list_add_tail(&transport->node, &lttng_transport_list);
  65 }
  66
  67 /**
  68  * lttng_transport_unregister - LTT transport unregistration
  69  * @transport: transport structure
  70  * Called with ust_lock held.
  71  */
  72 void lttng_transport_unregister(struct lttng_transport *transport)
  73 {
  74         cds_list_del(&transport->node);
  75 }
  76
  77 /**
  78  * lttng_counter_transport_register - LTTng counter transport registration
  79  * @transport: transport structure
  80  *
  81  * Registers a counter transport which can be used as output to extract
  82  * the data out of LTTng. Called with ust_lock held.
  83  */
  84 void lttng_counter_transport_register(struct lttng_counter_transport *transport)
  85 {
  86         cds_list_add_tail(&transport->node, &lttng_counter_transport_list);
  87 }
  88
  89 /**
  90  * lttng_counter_transport_unregister - LTTng counter transport unregistration
  91  * @transport: transport structure
  92  * Called with ust_lock held.
  93  */
  94 void lttng_counter_transport_unregister(struct lttng_counter_transport *transport)
  95 {
  96         cds_list_del(&transport->node);
  97 }
  98
  99 /*
 100  * Needed by comm layer.
 101  */
 102 struct lttng_enum *lttng_ust_enum_get_from_desc(struct lttng_session *session,
 103                 const struct lttng_enum_desc *enum_desc)
 104 {
 105         struct lttng_enum *_enum;
 106         struct cds_hlist_head *head;
 107         struct cds_hlist_node *node;
 108         size_t name_len = strlen(enum_desc->name);
 109         uint32_t hash;
 110
 111         hash = jhash(enum_desc->name, name_len, 0);
 112         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 113         cds_hlist_for_each_entry(_enum, node, head, hlist) {
 114                 assert(_enum->desc);
 115                 if (_enum->desc == enum_desc)
 116                         return _enum;
 117         }
 118         return NULL;
 119 }
 120
 121 size_t lttng_ust_dummy_get_size(struct lttng_ctx_field *field, size_t offset)
 122 {
 123         size_t size = 0;
 124
 125         size += lib_ring_buffer_align(offset, lttng_alignof(char));
 126         size += sizeof(char);           /* tag */
 127         return size;
 128 }
 129
 130 void lttng_ust_dummy_record(struct lttng_ctx_field *field,
 131                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 132                  struct lttng_channel *chan)
 133 {
 134         char sel_char = (char) LTTNG_UST_DYNAMIC_TYPE_NONE;
 135
 136         lib_ring_buffer_align_ctx(ctx, lttng_alignof(sel_char));
 137         chan->ops->event_write(ctx, &sel_char, sizeof(sel_char));
 138 }
 139
 140 void lttng_ust_dummy_get_value(struct lttng_ctx_field *field,
 141                 struct lttng_ctx_value *value)
 142 {
 143         value->sel = LTTNG_UST_DYNAMIC_TYPE_NONE;
 144 }
 145
 146 int lttng_context_is_app(const char *name)
 147 {
 148         if (strncmp(name, "$app.", strlen("$app.")) != 0) {
 149                 return 0;
 150         }
 151         return 1;
 152 }