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