liblttng-ust/ust-core.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #define _LGPL_SOURCE
   8 #include <stdint.h>
   9 #include <stddef.h>
  10 #include <stdlib.h>
  11
  12 #include "ust-events-internal.h"
  13 #include <usterr-signal-safe.h>
  14 #include "lttng-tracer-core.h"
  15 #include "jhash.h"
  16
  17 static CDS_LIST_HEAD(lttng_transport_list);
  18 static CDS_LIST_HEAD(lttng_counter_transport_list);
  19
  20 struct lttng_transport *lttng_transport_find(const char *name)
  21 {
  22         struct lttng_transport *transport;
  23
  24         cds_list_for_each_entry(transport, &lttng_transport_list, node) {
  25                 if (!strcmp(transport->name, name))
  26                         return transport;
  27         }
  28         return NULL;
  29 }
  30
  31 struct lttng_counter_transport *lttng_counter_transport_find(const char *name)
  32 {
  33         struct lttng_counter_transport *transport;
  34
  35         cds_list_for_each_entry(transport, &lttng_counter_transport_list, node) {
  36                 if (!strcmp(transport->name, name))
  37                         return transport;
  38         }
  39         return NULL;
  40 }
  41
  42 /**
  43  * lttng_transport_register - LTT transport registration
  44  * @transport: transport structure
  45  *
  46  * Registers a transport which can be used as output to extract the data out of
  47  * LTTng. Called with ust_lock held.
  48  */
  49 void lttng_transport_register(struct lttng_transport *transport)
  50 {
  51         cds_list_add_tail(&transport->node, &lttng_transport_list);
  52 }
  53
  54 /**
  55  * lttng_transport_unregister - LTT transport unregistration
  56  * @transport: transport structure
  57  * Called with ust_lock held.
  58  */
  59 void lttng_transport_unregister(struct lttng_transport *transport)
  60 {
  61         cds_list_del(&transport->node);
  62 }
  63
  64 /**
  65  * lttng_counter_transport_register - LTTng counter transport registration
  66  * @transport: transport structure
  67  *
  68  * Registers a counter transport which can be used as output to extract
  69  * the data out of LTTng. Called with ust_lock held.
  70  */
  71 void lttng_counter_transport_register(struct lttng_counter_transport *transport)
  72 {
  73         cds_list_add_tail(&transport->node, &lttng_counter_transport_list);
  74 }
  75
  76 /**
  77  * lttng_counter_transport_unregister - LTTng counter transport unregistration
  78  * @transport: transport structure
  79  * Called with ust_lock held.
  80  */
  81 void lttng_counter_transport_unregister(struct lttng_counter_transport *transport)
  82 {
  83         cds_list_del(&transport->node);
  84 }
  85
  86 /*
  87  * Needed by comm layer.
  88  */
  89 struct lttng_enum *lttng_ust_enum_get_from_desc(struct lttng_session *session,
  90                 const struct lttng_enum_desc *enum_desc)
  91 {
  92         struct lttng_enum *_enum;
  93         struct cds_hlist_head *head;
  94         struct cds_hlist_node *node;
  95         size_t name_len = strlen(enum_desc->name);
  96         uint32_t hash;
  97
  98         hash = jhash(enum_desc->name, name_len, 0);
  99         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 100         cds_hlist_for_each_entry(_enum, node, head, hlist) {
 101                 assert(_enum->desc);
 102                 if (_enum->desc == enum_desc)
 103                         return _enum;
 104         }
 105         return NULL;
 106 }
 107
 108 size_t lttng_ust_dummy_get_size(struct lttng_ctx_field *field, size_t offset)
 109 {
 110         size_t size = 0;
 111
 112         size += lib_ring_buffer_align(offset, lttng_alignof(char));
 113         size += sizeof(char);           /* tag */
 114         return size;
 115 }
 116
 117 void lttng_ust_dummy_record(struct lttng_ctx_field *field,
 118                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 119                  struct lttng_channel *chan)
 120 {
 121         char sel_char = (char) LTTNG_UST_DYNAMIC_TYPE_NONE;
 122
 123         lib_ring_buffer_align_ctx(ctx, lttng_alignof(sel_char));
 124         chan->ops->event_write(ctx, &sel_char, sizeof(sel_char));
 125 }
 126
 127 void lttng_ust_dummy_get_value(struct lttng_ctx_field *field,
 128                 struct lttng_ctx_value *value)
 129 {
 130         value->sel = LTTNG_UST_DYNAMIC_TYPE_NONE;
 131 }
 132
 133 int lttng_context_is_app(const char *name)
 134 {
 135         if (strncmp(name, "$app.", strlen("$app.")) != 0) {
 136                 return 0;
 137         }
 138         return 1;
 139 }