de4e93d70705bbb9787eb4e2a2e3faa54d152f18
[lttng-tools.git] / 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 #include <inttypes.h>
13
14 struct lttng_action;
15 struct lttng_condition;
16 struct lttng_trigger;
17 /* A set of triggers. */
18 struct lttng_triggers;
19
20 #ifdef __cplusplus
21 extern "C" {
22 #endif
23
24 enum lttng_register_trigger_status {
25 LTTNG_REGISTER_TRIGGER_STATUS_OK = 0,
26 LTTNG_REGISTER_TRIGGER_STATUS_INVALID = -1,
27 };
28
29 enum lttng_trigger_status {
30 LTTNG_TRIGGER_STATUS_OK = 0,
31 LTTNG_TRIGGER_STATUS_ERROR = -1,
32 LTTNG_TRIGGER_STATUS_UNKNOWN = -2,
33 LTTNG_TRIGGER_STATUS_INVALID = -3,
34 LTTNG_TRIGGER_STATUS_UNSET = -4,
35 LTTNG_TRIGGER_STATUS_UNSUPPORTED = -5,
36 LTTNG_TRIGGER_STATUS_PERMISSION_DENIED = -6,
37 };
38
39 enum lttng_trigger_firing_policy {
40 LTTNG_TRIGGER_FIRING_POLICY_EVERY_N = 0,
41 LTTNG_TRIGGER_FIRING_POLICY_ONCE_AFTER_N = 1,
42 };
43
44 /*
45 * Create a trigger object associating a condition and an action.
46 *
47 * A trigger associates a condition and an action to take whenever the
48 * condition evaluates to true. Such actions can, for example, consist
49 * in the emission of a notification to clients listening through
50 * notification channels.
51 *
52 * The caller retains the ownership of both the condition and action
53 * and both must be kept alive for the lifetime of the trigger object.
54 *
55 * If the action is a notification action with capture descriptors,
56 * the condition must be an event rule condition.
57 *
58 * A trigger must be registered in order to become activate and can
59 * be destroyed after its registration.
60 *
61 * Returns a trigger object on success, NULL on error.
62 * Trigger objects must be destroyed using the lttng_trigger_destroy()
63 * function.
64 */
65 extern struct lttng_trigger *lttng_trigger_create(
66 struct lttng_condition *condition, struct lttng_action *action);
67
68 /*
69 * Set the user identity (uid) of a trigger.
70 *
71 * Only available for the root user (uid 0).
72 *
73 * Returns LTTNG_TRIGGER_STATUS_OK on success,
74 * LTTNG_TRIGGER_STATUS_EPERM if not authorized,
75 * LTTNG_TRIGGER_STATUS_INVALID if invalid parameters are passed.
76 */
77 extern enum lttng_trigger_status lttng_trigger_set_owner_uid(
78 struct lttng_trigger *trigger, uid_t uid);
79
80 /*
81 * Get the user identity (uid) of a trigger.
82 *
83 * Returns LTTNG_TRIGGER_STATUS_OK on success,
84 * LTTNG_TRIGGER_STATUS_UNSET if unset,
85 * LTTNG_TRIGGER_STATUS_INVALID if invalid parameters are passed.
86 */
87 extern enum lttng_trigger_status lttng_trigger_get_owner_uid(
88 const struct lttng_trigger *trigger, uid_t *uid);
89
90 /*
91 * Get the condition of a trigger.
92 *
93 * The caller acquires no ownership of the returned condition.
94 *
95 * Returns a condition on success, NULL on error.
96 */
97 extern struct lttng_condition *lttng_trigger_get_condition(
98 struct lttng_trigger *trigger);
99
100 const struct lttng_condition *lttng_trigger_get_const_condition(
101 const struct lttng_trigger *trigger);
102
103 /*
104 * Get the action of a trigger.
105 *
106 * The caller acquires no ownership of the returned action.
107 *
108 * Returns an action on success, NULL on error.
109 */
110 extern struct lttng_action *lttng_trigger_get_action(
111 struct lttng_trigger *trigger);
112
113 const struct lttng_action *lttng_trigger_get_const_action(
114 const struct lttng_trigger *trigger);
115
116 /*
117 * Get the name of a trigger.
118 *
119 * The caller does not assume the ownership of the returned name.
120 * The name shall only only be used for the duration of the trigger's
121 * lifetime, or until a different name is set.
122 *
123 * Returns LTTNG_TRIGGER_STATUS_OK and a pointer to the trigger's name on
124 * success, LTTNG_TRIGGER_STATUS_INVALID if an invalid parameter is passed,
125 * or LTTNG_TRIGGER_STATUS_UNSET if a name was not set prior to this call.
126 */
127 extern enum lttng_trigger_status lttng_trigger_get_name(
128 const struct lttng_trigger *trigger, const char **name);
129
130 /*
131 * Set the trigger name.
132 *
133 * A name is optional.
134 * A name will be assigned on trigger registration if no name is set.
135 *
136 * The name is copied.
137 *
138 * Return LTTNG_TRIGGER_STATUS_OK on success, LTTNG_TRIGGER_STATUS_INVALID
139 * if invalid parameters are passed.
140 */
141 extern enum lttng_trigger_status lttng_trigger_set_name(
142 struct lttng_trigger *trigger, const char *name);
143
144 /*
145 * Set the trigger firing policy.
146 *
147 * This is optional. By default a trigger is set to fire each time the
148 * associated condition occurs.
149 *
150 * Threshold is the number of times the condition must be hit before the policy
151 * is enacted.
152 *
153 * Return LTTNG_TRIGGER_STATUS_OK on success, LTTNG_TRIGGER_STATUS_INVALID
154 * if invalid parameters are passed.
155 */
156 extern enum lttng_trigger_status lttng_trigger_set_firing_policy(
157 struct lttng_trigger *trigger,
158 enum lttng_trigger_firing_policy policy_type,
159 uint64_t threshold);
160
161 /*
162 * Get the trigger firing policy.
163 *
164 * Threshold is the number of time the condition must be hit before the policy is
165 * enacted.
166 *
167 * Return LTTNG_TRIGGER_STATUS_OK on success, LTTNG_TRIGGER_STATUS_INVALID
168 * if invalid parameters are passed.
169 */
170 extern enum lttng_trigger_status lttng_trigger_get_firing_policy(
171 const struct lttng_trigger *trigger,
172 enum lttng_trigger_firing_policy *policy_type,
173 uint64_t *threshold);
174
175 /*
176 * Destroy (frees) a trigger object.
177 */
178 extern void lttng_trigger_destroy(struct lttng_trigger *trigger);
179
180 /*
181 * Register a trigger to the session daemon.
182 *
183 * The trigger can be destroyed after this call.
184 *
185 * Return 0 on success, a negative LTTng error code on error.
186 */
187 extern int lttng_register_trigger(struct lttng_trigger *trigger);
188
189 /*
190 * Unregister a trigger from the session daemon.
191 *
192 * The trigger can be destroyed after this call.
193 *
194 * Return 0 on success, a negative LTTng error code on error.
195 */
196 extern int lttng_unregister_trigger(const struct lttng_trigger *trigger);
197
198 /*
199 * List triggers for the current user.
200 *
201 * On success, a newly-allocated trigger set is returned.
202 *
203 * The trigger set must be destroyed by the caller (see
204 * lttng_triggers_destroy()).
205 *
206 * Returns LTTNG_OK on success, else a suitable LTTng error code.
207 */
208 extern enum lttng_error_code lttng_list_triggers(
209 struct lttng_triggers **triggers);
210
211 /*
212 * Get a trigger from the set at a given index.
213 *
214 * Note that the trigger set maintains the ownership of the returned trigger.
215 * It must not be destroyed by the user, nor should a reference to it be held
216 * beyond the lifetime of the trigger set.
217 *
218 * Returns a trigger, or NULL on error.
219 */
220 extern const struct lttng_trigger *lttng_triggers_get_at_index(
221 const struct lttng_triggers *triggers, unsigned int index);
222
223 /*
224 * Get the number of triggers in a trigger set.
225 *
226 * Return LTTNG_TRIGGER_STATUS_OK on success,
227 * LTTNG_TRIGGER_STATUS_INVALID when invalid parameters are passed.
228 */
229 extern enum lttng_trigger_status lttng_triggers_get_count(
230 const struct lttng_triggers *triggers, unsigned int *count);
231
232 /*
233 * Destroy a trigger set.
234 */
235 extern void lttng_triggers_destroy(struct lttng_triggers *triggers);
236
237
238 #ifdef __cplusplus
239 }
240 #endif
241
242 #endif /* LTTNG_TRIGGER_H */
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