src/bin/lttng-sessiond/agent.hpp

   1 /*
   2  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   3  * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #ifndef LTTNG_SESSIOND_AGENT_H
  10 #define LTTNG_SESSIOND_AGENT_H
  11
  12 #include <common/hashtable/hashtable.hpp>
  13
  14 #include <lttng/lttng.h>
  15
  16 #include <inttypes.h>
  17 #include <urcu/urcu.h>
  18
  19 /* Agent protocol version that is verified during the agent registration. */
  20 #define AGENT_MAJOR_VERSION 2
  21 #define AGENT_MINOR_VERSION 0
  22
  23 /*
  24  * Hash table that contains the agent app created upon registration indexed by
  25  * socket. Global to the session daemon.
  26  */
  27 extern struct lttng_ht *the_agent_apps_ht_by_sock;
  28
  29 /*
  30  * Hash table that contains the trigger agents by domain */
  31 extern struct lttng_ht *the_trigger_agents_ht_by_domain;
  32
  33 struct agent_ht_key {
  34         const char *name;
  35         int loglevel_value;
  36         enum lttng_loglevel_type loglevel_type;
  37         const char *filter_expression;
  38 };
  39
  40 /*
  41  * Registration message payload from an agent application. The PID is used to
  42  * find back the corresponding UST app object so both socket can be linked.
  43  */
  44 struct agent_register_msg {
  45         /* This maps to a lttng_domain_type. */
  46         uint32_t domain;
  47         uint32_t pid;
  48         uint32_t major_version;
  49         uint32_t minor_version;
  50 };
  51
  52 /*
  53  * Agent application object created after a successful registration. This
  54  * object is linked to its associated UST app by their PID through hash table
  55  * lookups.
  56  */
  57 struct agent_app {
  58         /*
  59          * PID sent during registration of an agent application.
  60          */
  61         pid_t pid;
  62
  63         /* Domain of the application. */
  64         enum lttng_domain_type domain;
  65
  66         /*
  67          * AGENT TCP socket that was created upon registration.
  68          */
  69         struct lttcomm_sock *sock;
  70
  71         /* Initialized with the AGENT sock value. */
  72         struct lttng_ht_node_ulong node;
  73 };
  74
  75 /*
  76  * Agent event representation.
  77  * Accesses to this structure are protected by the session list lock.
  78  */
  79 struct agent_event {
  80         /* Name of the event. */
  81         char name[LTTNG_SYMBOL_NAME_LEN];
  82         int loglevel_value;
  83         enum lttng_loglevel_type loglevel_type;
  84
  85         /*
  86          * Tells if the event is enabled or not on the agent. While this can be
  87          * implicitly tested as a boolean, it is in fact a reference count and
  88          * the AGENT_EVENT_IS_ENABLED macro should be used to prevent accidental
  89          * comparisons to non-zero literals (e.g. '1').
  90          *
  91          * Multiple triggers and events can map to the same agent event as it
  92          * is merely a "filter" in front of a user space tracer enabler.
  93          *
  94          * This count is updated to ensure an event is only disabled when all
  95          * matching enablers are disabled.
  96          */
  97         unsigned int enabled_count;
  98
  99         /* Hash table node of the agent domain object. */
 100         struct lttng_ht_node_str node;
 101
 102         /* Filter associated with the event. NULL if none. */
 103         struct lttng_bytecode *filter;
 104         char *filter_expression;
 105         struct lttng_event_exclusion *exclusion;
 106 };
 107
 108 #define AGENT_EVENT_IS_ENABLED(agent_event) (!!(agent_event)->enabled_count)
 109
 110 /*
 111  * Agent object containing events enabled/disabled for a given domain in a
 112  * scope. The scope is typically a session, but can also be "global" in the
 113  * context of event notifiers: see event_notifiers_find_agent().
 114  */
 115 struct agent {
 116         /*
 117          * This indicates if that domain is being used meaning if at least one
 118          * event has been at some point in time added to it. This is used so when
 119          * listing domains for a session, we can tell or not if the agent is
 120          * actually enabled.
 121          */
 122         unsigned int being_used:1;
 123
 124         /* What domain this agent is. */
 125         enum lttng_domain_type domain;
 126
 127         /* Contains event indexed by name. */
 128         struct lttng_ht *events;
 129
 130         /* Application context list (struct agent_app_ctx). */
 131         struct cds_list_head app_ctx_list;
 132
 133         /* Node used for the hash table indexed by domain type. */
 134         struct lttng_ht_node_u64 node;
 135 };
 136
 137 /* Allocate agent apps hash table */
 138 int agent_app_ht_alloc();
 139 /* Clean-up agent apps hash table */
 140 void agent_app_ht_clean();
 141
 142 /* Initialize an already allocated agent domain. */
 143 int agent_init(struct agent *agt);
 144 struct agent *agent_create(enum lttng_domain_type domain);
 145 void agent_destroy(struct agent *agt);
 146 void agent_add(struct agent *agt, struct lttng_ht *ht);
 147
 148 /* Agent event API. */
 149 struct agent_event *agent_create_event(const char *name,
 150                                        enum lttng_loglevel_type loglevel_type,
 151                                        int loglevel_value,
 152                                        struct lttng_bytecode *filter,
 153                                        char *filter_expression);
 154 void agent_add_event(struct agent_event *event, struct agent *agt);
 155
 156 struct agent_event *agent_find_event(const char *name,
 157                                      enum lttng_loglevel_type loglevel_type,
 158                                      int loglevel_value,
 159                                      const char *filter_expression,
 160                                      struct agent *agt);
 161 void agent_find_events_by_name(const char *name, struct agent *agt, struct lttng_ht_iter *iter);
 162 void agent_event_next_duplicate(const char *name, struct agent *agt, struct lttng_ht_iter *iter);
 163 void agent_delete_event(struct agent_event *event, struct agent *agt);
 164 void agent_destroy_event(struct agent_event *event);
 165
 166 /* Agent context API.*/
 167 int agent_enable_context(const struct lttng_event_context *ctx, enum lttng_domain_type domain);
 168 int agent_add_context(const struct lttng_event_context *ctx, struct agent *agt);
 169
 170 /* Agent app API. */
 171 struct agent_app *
 172 agent_create_app(pid_t pid, enum lttng_domain_type domain, struct lttcomm_sock *sock);
 173 void agent_add_app(struct agent_app *app);
 174 void agent_delete_app(struct agent_app *app);
 175 struct agent_app *agent_find_app_by_sock(int sock);
 176 void agent_destroy_app(struct agent_app *app);
 177 void agent_destroy_app_by_sock(int sock);
 178 int agent_send_registration_done(struct agent_app *app);
 179
 180 /* Agent action API */
 181 int agent_enable_event(struct agent_event *event, enum lttng_domain_type domain);
 182 int agent_disable_event(struct agent_event *event, enum lttng_domain_type domain);
 183 void agent_update(const struct agent *agt, const struct agent_app *app);
 184 int agent_list_events(struct lttng_event **events, enum lttng_domain_type domain);
 185
 186 struct agent_event *agent_find_event_by_trigger(const struct lttng_trigger *trigger,
 187                                                 struct agent *agt);
 188
 189 /* Global event notifier per-domain agents. */
 190 struct agent *agent_find_by_event_notifier_domain(enum lttng_domain_type domain_type);
 191 void agent_by_event_notifier_domain_ht_destroy();
 192 int agent_by_event_notifier_domain_ht_create();
 193
 194 #endif /* LTTNG_SESSIOND_AGENT_H */