include/lttng/trigger/trigger.h

   1 /*
   2  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_TRIGGER_H
   9 #define LTTNG_TRIGGER_H
  10
  11 #include <sys/types.h>
  12
  13 struct lttng_action;
  14 struct lttng_condition;
  15 struct lttng_trigger;
  16 /* A set of triggers. */
  17 struct lttng_triggers;
  18
  19 #ifdef __cplusplus
  20 extern "C" {
  21 #endif
  22
  23 enum lttng_register_trigger_status {
  24         LTTNG_REGISTER_TRIGGER_STATUS_OK = 0,
  25         LTTNG_REGISTER_TRIGGER_STATUS_INVALID = -1,
  26 };
  27
  28 enum lttng_trigger_status {
  29         LTTNG_TRIGGER_STATUS_OK = 0,
  30         LTTNG_TRIGGER_STATUS_ERROR = -1,
  31         LTTNG_TRIGGER_STATUS_UNKNOWN = -2,
  32         LTTNG_TRIGGER_STATUS_INVALID = -3,
  33         LTTNG_TRIGGER_STATUS_UNSET = -4,
  34         LTTNG_TRIGGER_STATUS_UNSUPPORTED = -5,
  35         LTTNG_TRIGGER_STATUS_PERMISSION_DENIED = -6,
  36 };
  37
  38 /*
  39  * Create a trigger object associating a condition and an action.
  40  *
  41  * A trigger associates a condition and an action to take whenever the
  42  * condition evaluates to true. Such actions can, for example, consist
  43  * in the emission of a notification to clients listening through
  44  * notification channels.
  45  *
  46  * The caller retains the ownership of both the condition and action
  47  * and both must be kept alive for the lifetime of the trigger object.
  48  *
  49  * A trigger must be registered in order to become activate and can
  50  * be destroyed after its registration.
  51  *
  52  * Returns a trigger object on success, NULL on error.
  53  * Trigger objects must be destroyed using the lttng_trigger_destroy()
  54  * function.
  55  */
  56 extern struct lttng_trigger *lttng_trigger_create(
  57                 struct lttng_condition *condition, struct lttng_action *action);
  58
  59 /*
  60  * Set the user identity (uid) of a trigger.
  61  *
  62  * Only available for the root user (uid 0).
  63  *
  64  * Returns LTTNG_TRIGGER_STATUS_OK on success,
  65  * LTTNG_TRIGGER_STATUS_EPERM if not authorized,
  66  * LTTNG_TRIGGER_STATUS_INVALID if invalid parameters are passed.
  67  */
  68 extern enum lttng_trigger_status lttng_trigger_set_owner_uid(
  69                 struct lttng_trigger *trigger, uid_t uid);
  70
  71 /*
  72  * Get the user identity (uid) of a trigger.
  73  *
  74  * Returns LTTNG_TRIGGER_STATUS_OK on success,
  75  * LTTNG_TRIGGER_STATUS_UNSET if unset,
  76  * LTTNG_TRIGGER_STATUS_INVALID if invalid parameters are passed.
  77  */
  78 extern enum lttng_trigger_status lttng_trigger_get_owner_uid(
  79                 const struct lttng_trigger *trigger, uid_t *uid);
  80
  81 /*
  82  * Get the condition of a trigger.
  83  *
  84  * The caller acquires no ownership of the returned condition.
  85  *
  86  * Returns a condition on success, NULL on error.
  87  */
  88 extern struct lttng_condition *lttng_trigger_get_condition(
  89                 struct lttng_trigger *trigger);
  90
  91 /*
  92  * Get the action of a trigger.
  93  *
  94  * The caller acquires no ownership of the returned action.
  95  *
  96  * Returns an action on success, NULL on error.
  97  */
  98 extern struct lttng_action *lttng_trigger_get_action(
  99                 struct lttng_trigger *trigger);
 100
 101
 102 /*
 103  * Get the name of a trigger.
 104  *
 105  * The caller does not assume the ownership of the returned name.
 106  * The name shall only only be used for the duration of the trigger's
 107  * lifetime, or until a different name is set.
 108  *
 109  * Returns LTTNG_TRIGGER_STATUS_OK and a pointer to the trigger's name on
 110  * success, LTTNG_TRIGGER_STATUS_INVALID if an invalid parameter is passed,
 111  * or LTTNG_TRIGGER_STATUS_UNSET if a name was not set prior to this call.
 112  */
 113 extern enum lttng_trigger_status lttng_trigger_get_name(
 114                 const struct lttng_trigger *trigger, const char **name);
 115
 116 /*
 117  * Set the trigger name.
 118  *
 119  * A name is optional.
 120  * A name will be assigned on trigger registration if no name is set.
 121  *
 122  * The name is copied.
 123  *
 124  * Return LTTNG_TRIGGER_STATUS_OK on success, LTTNG_TRIGGER_STATUS_INVALID
 125  * if invalid parameters are passed.
 126  */
 127 extern enum lttng_trigger_status lttng_trigger_set_name(
 128                 struct lttng_trigger *trigger, const char *name);
 129
 130 /*
 131  * Destroy (frees) a trigger object.
 132  */
 133 extern void lttng_trigger_destroy(struct lttng_trigger *trigger);
 134
 135 /*
 136  * Register a trigger to the session daemon.
 137  *
 138  * The trigger can be destroyed after this call.
 139  *
 140  * Return 0 on success, a negative LTTng error code on error.
 141  */
 142 extern int lttng_register_trigger(struct lttng_trigger *trigger);
 143
 144 /*
 145  * Unregister a trigger from the session daemon.
 146  *
 147  * The trigger can be destroyed after this call.
 148  *
 149  * Return 0 on success, a negative LTTng error code on error.
 150  */
 151 extern int lttng_unregister_trigger(struct lttng_trigger *trigger);
 152
 153 /*
 154  * Get a trigger from the set at a given index.
 155  *
 156  * Note that the trigger set maintains the ownership of the returned trigger.
 157  * It must not be destroyed by the user, nor should a reference to it be held
 158  * beyond the lifetime of the trigger set.
 159  *
 160  * Returns a trigger, or NULL on error.
 161  */
 162 extern const struct lttng_trigger *lttng_triggers_get_at_index(
 163                 const struct lttng_triggers *triggers, unsigned int index);
 164
 165 /*
 166  * Get the number of triggers in a trigger set.
 167  *
 168  * Return LTTNG_TRIGGER_STATUS_OK on success,
 169  * LTTNG_TRIGGER_STATUS_INVALID when invalid parameters are passed.
 170  */
 171 extern enum lttng_trigger_status lttng_triggers_get_count(
 172                 const struct lttng_triggers *triggers, unsigned int *count);
 173
 174 /*
 175  * Destroy a trigger set.
 176  */
 177 extern void lttng_triggers_destroy(struct lttng_triggers *triggers);
 178
 179
 180 #ifdef __cplusplus
 181 }
 182 #endif
 183
 184 #endif /* LTTNG_TRIGGER_H */