trigger: keep state of if a trigger is currently registered
[lttng-tools.git] / include / lttng / trigger / trigger-internal.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_INTERNAL_H
9 #define LTTNG_TRIGGER_INTERNAL_H
10
11 #include <common/credentials.h>
12 #include <common/dynamic-array.h>
13 #include <common/macros.h>
14 #include <common/optional.h>
15 #include <lttng/trigger/trigger.h>
16 #include <pthread.h>
17 #include <stdbool.h>
18 #include <stdint.h>
19 #include <sys/types.h>
20 #include <urcu/ref.h>
21
22 struct lttng_payload;
23 struct lttng_payload_view;
24
25 struct lttng_trigger {
26 /* Reference counting is only exposed to internal users. */
27 struct urcu_ref ref;
28
29 struct lttng_condition *condition;
30 struct lttng_action *action;
31 char *name;
32 /* For now only the uid portion of the credentials is used. */
33 struct lttng_credentials creds;
34 /*
35 * Internal use only.
36 * The unique token passed to the tracer to identify an event-rule
37 * notification.
38 */
39 LTTNG_OPTIONAL(uint64_t) tracer_token;
40
41 /*
42 * Is the trigger registered?
43 *
44 * This is necessary since a reference holder might be interested in the
45 * overall state of the trigger from the point of view of its owner.
46 *
47 * The main user is the action executor since we want to prevent the
48 * execution of actions related to a trigger that is unregistered.
49 *
50 * Not considered for `is_equal`.
51 */
52 bool registered;
53
54 /*
55 * The lock is used to protect against concurrent trigger execution and
56 * trigger removal.
57 */
58 pthread_mutex_t lock;
59 };
60
61 struct lttng_triggers {
62 struct lttng_dynamic_pointer_array array;
63 };
64
65 struct lttng_trigger_comm {
66 /*
67 * Credentials, only the uid portion is used for now.
68 * Used as an override when desired by the root user.
69 */
70 uint64_t uid;
71 /*
72 * Length of the variable length payload (name, condition, and
73 * an action).
74 */
75 uint32_t length;
76 /* Includes '\0' terminator. */
77 uint32_t name_length;
78 /* A null-terminated name, a condition, and an action follow. */
79 char payload[];
80 } LTTNG_PACKED;
81
82 struct lttng_triggers_comm {
83 uint32_t count;
84 uint32_t length;
85 /* Count * lttng_trigger_comm structure */
86 char payload[];
87 };
88
89 LTTNG_HIDDEN
90 ssize_t lttng_trigger_create_from_payload(struct lttng_payload_view *view,
91 struct lttng_trigger **trigger);
92
93 LTTNG_HIDDEN
94 int lttng_trigger_serialize(const struct lttng_trigger *trigger,
95 struct lttng_payload *payload);
96
97 LTTNG_HIDDEN
98 bool lttng_trigger_validate(const struct lttng_trigger *trigger);
99
100 LTTNG_HIDDEN
101 int lttng_trigger_assign_name(
102 struct lttng_trigger *dst, const struct lttng_trigger *src);
103
104 LTTNG_HIDDEN
105 void lttng_trigger_set_tracer_token(
106 struct lttng_trigger *trigger, uint64_t token);
107
108 LTTNG_HIDDEN
109 uint64_t lttng_trigger_get_tracer_token(const struct lttng_trigger *trigger);
110
111 LTTNG_HIDDEN
112 int lttng_trigger_generate_name(struct lttng_trigger *trigger,
113 uint64_t unique_id);
114
115 LTTNG_HIDDEN
116 bool lttng_trigger_is_equal(
117 const struct lttng_trigger *a, const struct lttng_trigger *b);
118
119 LTTNG_HIDDEN
120 void lttng_trigger_get(struct lttng_trigger *trigger);
121
122 LTTNG_HIDDEN
123 void lttng_trigger_put(struct lttng_trigger *trigger);
124
125 /*
126 * Allocate a new set of triggers.
127 * The returned object must be freed via lttng_triggers_destroy.
128 */
129 LTTNG_HIDDEN
130 struct lttng_triggers *lttng_triggers_create(void);
131
132 /*
133 * Return the a pointer to a mutable element at index "index" of an
134 * lttng_triggers set.
135 *
136 * This differs from the public `lttng_triggers_get_at_index` in that
137 * the returned pointer to a mutable trigger.
138 *
139 * The ownership of the trigger set element is NOT transfered.
140 * The returned object can NOT be freed via lttng_trigger_destroy.
141 */
142 LTTNG_HIDDEN
143 struct lttng_trigger *lttng_triggers_borrow_mutable_at_index(
144 const struct lttng_triggers *triggers, unsigned int index);
145
146 /*
147 * Add a trigger to the triggers set.
148 *
149 * A reference to the added trigger is acquired on behalf of the trigger set
150 * on success.
151 */
152 LTTNG_HIDDEN
153 int lttng_triggers_add(
154 struct lttng_triggers *triggers, struct lttng_trigger *trigger);
155
156 /*
157 * Serialize a trigger set to an lttng_payload object.
158 * Return LTTNG_OK on success, negative lttng error code on error.
159 */
160 LTTNG_HIDDEN
161 int lttng_triggers_serialize(const struct lttng_triggers *triggers,
162 struct lttng_payload *payload);
163
164 LTTNG_HIDDEN
165 ssize_t lttng_triggers_create_from_payload(struct lttng_payload_view *view,
166 struct lttng_triggers **triggers);
167
168 LTTNG_HIDDEN
169 const struct lttng_credentials *lttng_trigger_get_credentials(
170 const struct lttng_trigger *trigger);
171
172 LTTNG_HIDDEN
173 void lttng_trigger_set_credentials(struct lttng_trigger *trigger,
174 const struct lttng_credentials *creds);
175
176 /*
177 * Return the type of any underlying domain restriction. If no particular
178 * requirement is present, returns LTTNG_DOMAIN_NONE.
179 */
180 LTTNG_HIDDEN
181 enum lttng_domain_type lttng_trigger_get_underlying_domain_type_restriction(
182 const struct lttng_trigger *trigger);
183
184 /*
185 * Generate any bytecode related to the trigger.
186 * On success LTTNG_OK. On error, returns lttng_error code.
187 */
188 LTTNG_HIDDEN
189 enum lttng_error_code lttng_trigger_generate_bytecode(
190 struct lttng_trigger *trigger,
191 const struct lttng_credentials *creds);
192
193 LTTNG_HIDDEN
194 struct lttng_trigger *lttng_trigger_copy(const struct lttng_trigger *trigger);
195
196 /*
197 * A given trigger needs a tracer notifier if
198 * it has an event-rule condition,
199 * AND
200 * it has one or more sessiond-execution action.
201 */
202 LTTNG_HIDDEN
203 bool lttng_trigger_needs_tracer_notifier(const struct lttng_trigger *trigger);
204
205 LTTNG_HIDDEN
206 void lttng_trigger_set_as_registered(struct lttng_trigger *trigger);
207
208 LTTNG_HIDDEN
209 void lttng_trigger_set_as_unregistered(struct lttng_trigger *trigger);
210
211 /*
212 * The trigger must be locked before calling lttng_trigger_is_registered.
213 *
214 * The lock is necessary since a trigger can be unregistered at any time.
215 *
216 * Manipulations requiring that the trigger be registered must always acquire
217 * the trigger lock for the duration of the manipulation using
218 * `lttng_trigger_lock` and `lttng_trigger_unlock`.
219 */
220 LTTNG_HIDDEN
221 bool lttng_trigger_is_registered(struct lttng_trigger *trigger);
222
223 LTTNG_HIDDEN
224 void lttng_trigger_lock(struct lttng_trigger *trigger);
225
226 LTTNG_HIDDEN
227 void lttng_trigger_unlock(struct lttng_trigger *trigger);
228
229 #endif /* LTTNG_TRIGGER_INTERNAL_H */
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