src/bin/lttng-sessiond/agent.h

   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 <inttypes.h>
  13
  14 #include <common/hashtable/hashtable.h>
  15 #include <lttng/lttng.h>
  16
  17 /* Agent protocol version that is verified during the agent registration. */
  18 #define AGENT_MAJOR_VERSION             2
  19 #define AGENT_MINOR_VERSION             0
  20
  21 /*
  22  * Hash table that contains the agent app created upon registration indexed by
  23  * socket. Global to the session daemon.
  24  */
  25 extern struct lttng_ht *the_agent_apps_ht_by_sock;
  26
  27 /*
  28  * Hash table that contains the trigger agents by domain */
  29 extern struct lttng_ht *the_trigger_agents_ht_by_domain;
  30
  31 struct agent_ht_key {
  32         const char *name;
  33         int loglevel_value;
  34         enum lttng_loglevel_type loglevel_type;
  35         const char *filter_expression;
  36 };
  37
  38 /*
  39  * Registration message payload from an agent application. The PID is used to
  40  * find back the corresponding UST app object so both socket can be linked.
  41  */
  42 struct agent_register_msg {
  43         /* This maps to a lttng_domain_type. */
  44         uint32_t domain;
  45         uint32_t pid;
  46         uint32_t major_version;
  47         uint32_t minor_version;
  48 };
  49
  50 /*
  51  * Agent application object created after a successful registration. This
  52  * object is linked to its associated UST app by their PID through hash table
  53  * lookups.
  54  */
  55 struct agent_app {
  56         /*
  57          * PID sent during registration of an agent application.
  58          */
  59         pid_t pid;
  60
  61         /* Domain of the application. */
  62         enum lttng_domain_type domain;
  63
  64         /*
  65          * AGENT TCP socket that was created upon registration.
  66          */
  67         struct lttcomm_sock *sock;
  68
  69         /* Initialized with the AGENT sock value. */
  70         struct lttng_ht_node_ulong node;
  71 };
  72
  73 /*
  74  * Agent event representation.
  75  * Accesses to this structure are protected by the session list lock.
  76  */
  77 struct agent_event {
  78         /* Name of the event. */
  79         char name[LTTNG_SYMBOL_NAME_LEN];
  80         int loglevel_value;
  81         enum lttng_loglevel_type loglevel_type;
  82
  83         /*
  84          * Tells if the event is enabled or not on the agent. While this can be
  85          * implicitly tested as a boolean, it is in fact a reference count and
  86          * the AGENT_EVENT_IS_ENABLED macro should be used to prevent accidental
  87          * comparisons to non-zero literals (e.g. '1').
  88          *
  89          * Multiple triggers and events can map to the same agent event as it
  90          * is merely a "filter" in front of a user space tracer enabler.
  91          *
  92          * This count is updated to ensure an event is only disabled when all
  93          * matching enablers are disabled.
  94          */
  95         unsigned int enabled_count;
  96
  97         /* Hash table node of the agent domain object. */
  98         struct lttng_ht_node_str node;
  99
 100         /* Filter associated with the event. NULL if none. */
 101         struct lttng_bytecode *filter;
 102         char *filter_expression;
 103         struct lttng_event_exclusion *exclusion;
 104 };
 105
 106 #define AGENT_EVENT_IS_ENABLED(agent_event) (!!agent_event->enabled_count)
 107
 108 /*
 109  * Agent object containing events enabled/disabled for a given domain in a
 110  * scope. The scope is typically a session, but can also be "global" in the
 111  * context of event notifiers: see event_notifiers_find_agent().
 112  */
 113 struct agent {
 114         /*
 115          * This indicates if that domain is being used meaning if at least one
 116          * event has been at some point in time added to it. This is used so when
 117          * listing domains for a session, we can tell or not if the agent is
 118          * actually enabled.
 119          */
 120         unsigned int being_used:1;
 121
 122         /* What domain this agent is. */
 123         enum lttng_domain_type domain;
 124
 125         /* Contains event indexed by name. */
 126         struct lttng_ht *events;
 127
 128         /* Application context list (struct agent_app_ctx). */
 129         struct cds_list_head app_ctx_list;
 130
 131         /* Node used for the hash table indexed by domain type. */
 132         struct lttng_ht_node_u64 node;
 133 };
 134
 135 /* Allocate agent apps hash table */
 136 int agent_app_ht_alloc(void);
 137 /* Clean-up agent apps hash table */
 138 void agent_app_ht_clean(void);
 139
 140 /* Initialize an already allocated agent domain. */
 141 int agent_init(struct agent *agt);
 142 struct agent *agent_create(enum lttng_domain_type domain);
 143 void agent_destroy(struct agent *agt);
 144 void agent_add(struct agent *agt, struct lttng_ht *ht);
 145
 146 /* Agent event API. */
 147 struct agent_event *agent_create_event(const char *name,
 148                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
 149                 struct lttng_bytecode *filter,
 150                 char *filter_expression);
 151 void agent_add_event(struct agent_event *event, struct agent *agt);
 152
 153 struct agent_event *agent_find_event(const char *name,
 154                 enum lttng_loglevel_type loglevel_type,
 155                 int loglevel_value,
 156                 const char *filter_expression,
 157                 struct agent *agt);
 158 void agent_find_events_by_name(const char *name, struct agent *agt,
 159                 struct lttng_ht_iter* iter);
 160 void agent_event_next_duplicate(const char *name,
 161                 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,
 167                 enum lttng_domain_type domain);
 168 int agent_add_context(const struct lttng_event_context *ctx,
 169                 struct agent *agt);
 170
 171 /* Agent app API. */
 172 struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
 173                 struct lttcomm_sock *sock);
 174 void agent_add_app(struct agent_app *app);
 175 void agent_delete_app(struct agent_app *app);
 176 struct agent_app *agent_find_app_by_sock(int sock);
 177 void agent_destroy_app(struct agent_app *app);
 178 void agent_destroy_app_by_sock(int sock);
 179 int agent_send_registration_done(struct agent_app *app);
 180
 181 /* Agent action API */
 182 int agent_enable_event(struct agent_event *event,
 183                 enum lttng_domain_type domain);
 184 int agent_disable_event(struct agent_event *event,
 185                 enum lttng_domain_type domain);
 186 void agent_update(const struct agent *agt, const struct agent_app *app);
 187 int agent_list_events(struct lttng_event **events,
 188                 enum lttng_domain_type domain);
 189
 190 struct agent_event *agent_find_event_by_trigger(
 191                 const struct lttng_trigger *trigger, struct agent *agt);
 192
 193 /* Global event notifier per-domain agents. */
 194 struct agent *agent_find_by_event_notifier_domain(
 195                 enum lttng_domain_type domain_type);
 196 void agent_by_event_notifier_domain_ht_destroy(void);
 197 int agent_by_event_notifier_domain_ht_create(void);
 198
 199 #endif /* LTTNG_SESSIOND_AGENT_H */