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 #include <lttng/ust-events.h>
  12 #include <usterr-signal-safe.h>
  13 #include "lttng-tracer-core.h"
  14 #include "jhash.h"
  15
  16 static CDS_LIST_HEAD(lttng_transport_list);
  17 static CDS_LIST_HEAD(lttng_counter_transport_list);
  18
  19 struct lttng_transport *lttng_transport_find(const char *name)
  20 {
  21         struct lttng_transport *transport;
  22
  23         cds_list_for_each_entry(transport, &lttng_transport_list, node) {
  24                 if (!strcmp(transport->name, name))
  25                         return transport;
  26         }
  27         return NULL;
  28 }
  29
  30 struct lttng_counter_transport *lttng_counter_transport_find(const char *name)
  31 {
  32         struct lttng_counter_transport *transport;
  33
  34         cds_list_for_each_entry(transport, &lttng_counter_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  * lttng_counter_transport_register - LTTng counter transport registration
  65  * @transport: transport structure
  66  *
  67  * Registers a counter transport which can be used as output to extract
  68  * the data out of LTTng. Called with ust_lock held.
  69  */
  70 void lttng_counter_transport_register(struct lttng_counter_transport *transport)
  71 {
  72         cds_list_add_tail(&transport->node, &lttng_counter_transport_list);
  73 }
  74
  75 /**
  76  * lttng_counter_transport_unregister - LTTng counter transport unregistration
  77  * @transport: transport structure
  78  * Called with ust_lock held.
  79  */
  80 void lttng_counter_transport_unregister(struct lttng_counter_transport *transport)
  81 {
  82         cds_list_del(&transport->node);
  83 }
  84
  85 /*
  86  * Needed by comm layer.
  87  */
  88 struct lttng_enum *lttng_ust_enum_get_from_desc(struct lttng_session *session,
  89                 const struct lttng_enum_desc *enum_desc)
  90 {
  91         struct lttng_enum *_enum;
  92         struct cds_hlist_head *head;
  93         struct cds_hlist_node *node;
  94         size_t name_len = strlen(enum_desc->name);
  95         uint32_t hash;
  96
  97         hash = jhash(enum_desc->name, name_len, 0);
  98         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
  99         cds_hlist_for_each_entry(_enum, node, head, hlist) {
 100                 assert(_enum->desc);
 101                 if (_enum->desc == enum_desc)
 102                         return _enum;
 103         }
 104         return NULL;
 105 }
 106
 107 size_t lttng_ust_dummy_get_size(struct lttng_ctx_field *field, size_t offset)
 108 {
 109         size_t size = 0;
 110
 111         size += lib_ring_buffer_align(offset, lttng_alignof(char));
 112         size += sizeof(char);           /* tag */
 113         return size;
 114 }
 115
 116 void lttng_ust_dummy_record(struct lttng_ctx_field *field,
 117                  struct lttng_ust_lib_ring_buffer_ctx *ctx,
 118                  struct lttng_channel *chan)
 119 {
 120         char sel_char = (char) LTTNG_UST_DYNAMIC_TYPE_NONE;
 121
 122         lib_ring_buffer_align_ctx(ctx, lttng_alignof(sel_char));
 123         chan->ops->event_write(ctx, &sel_char, sizeof(sel_char));
 124 }
 125
 126 void lttng_ust_dummy_get_value(struct lttng_ctx_field *field,
 127                 struct lttng_ctx_value *value)
 128 {
 129         value->sel = LTTNG_UST_DYNAMIC_TYPE_NONE;
 130 }
 131
 132 int lttng_context_is_app(const char *name)
 133 {
 134         if (strncmp(name, "$app.", strlen("$app.")) != 0) {
 135                 return 0;
 136         }
 137         return 1;
 138 }