Fix RCU-related hangs: incorrect lttng_ht_destroy use
[lttng-tools.git] / src / bin / lttng-sessiond / ust-registry.h
CommitLineData
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1/*
2 * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License, version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 51
15 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18#ifndef LTTNG_UST_REGISTRY_H
19#define LTTNG_UST_REGISTRY_H
20
21#include <pthread.h>
22#include <stdint.h>
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23
24#include <common/hashtable/hashtable.h>
25#include <common/compat/uuid.h>
26
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27#include "ust-ctl.h"
28
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29#define CTF_SPEC_MAJOR 1
30#define CTF_SPEC_MINOR 8
31
32struct ust_app;
33
34struct ust_registry_session {
35 /*
7972aab2 36 * With multiple writers and readers, use this lock to access the registry.
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37 * Can nest within the ust app session lock.
38 */
39 pthread_mutex_t lock;
40 /* Next channel ID available for a newly registered channel. */
41 uint32_t next_channel_id;
42 /* Once this value reaches UINT32_MAX, no more id can be allocated. */
43 uint32_t used_channel_id;
44 /* Universal unique identifier used by the tracer. */
45 unsigned char uuid[UUID_LEN];
46
47 /* session ABI description */
48
49 /* Size of long, in bits */
50 unsigned int bits_per_long;
51 /* Alignment, in bits */
52 unsigned int uint8_t_alignment,
53 uint16_t_alignment,
54 uint32_t_alignment,
55 uint64_t_alignment,
56 long_alignment;
57 /* endianness */
58 int byte_order; /* BIG_ENDIAN or LITTLE_ENDIAN */
59
60 /* Generated metadata. */
61 char *metadata; /* NOT null-terminated ! Use memcpy. */
62 size_t metadata_len, metadata_alloc_len;
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63 /* Length of bytes sent to the consumer. */
64 size_t metadata_len_sent;
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65 /*
66 * Hash table containing channels sent by the UST tracer. MUST be accessed
67 * with a RCU read side lock acquired.
68 */
69 struct lttng_ht *channels;
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70 /* Unique key to identify the metadata on the consumer side. */
71 uint64_t metadata_key;
72 /*
73 * Indicates if the metadata is closed on the consumer side. This is to
74 * avoid double close of metadata when an application unregisters AND
75 * deletes its sessions.
76 */
77 unsigned int metadata_closed;
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78};
79
80struct ust_registry_channel {
45893984 81 uint64_t key;
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82 /* Id set when replying to a register channel. */
83 uint32_t chan_id;
84 enum ustctl_channel_header header_type;
85
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86 /*
87 * Flag for this channel if the metadata was dumped once during
88 * registration. 0 means no, 1 yes.
89 */
90 unsigned int metadata_dumped;
91 /* Indicates if this channel registry has already been registered. */
92 unsigned int register_done;
93
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94 /*
95 * Hash table containing events sent by the UST tracer. MUST be accessed
96 * with a RCU read side lock acquired.
97 */
98 struct lttng_ht *ht;
99 /* Next event ID available for a newly registered event. */
100 uint32_t next_event_id;
101 /* Once this value reaches UINT32_MAX, no more id can be allocated. */
102 uint32_t used_event_id;
103 /*
104 * Context fields of the registry. Context are per channel. Allocated by a
105 * register channel notification from the UST tracer.
106 */
107 size_t nr_ctx_fields;
108 struct ustctl_field *ctx_fields;
45893984 109 struct lttng_ht_node_u64 node;
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110 /* For delayed reclaim */
111 struct rcu_head rcu_head;
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112};
113
114/*
115 * Event registered from a UST tracer sent to the session daemon. This is
116 * indexed and matched by <event_name/signature>.
117 */
118struct ust_registry_event {
119 int id;
120 /* Both objd are set by the tracer. */
121 int session_objd;
122 int channel_objd;
123 /* Name of the event returned by the tracer. */
124 char name[LTTNG_UST_SYM_NAME_LEN];
125 char *signature;
126 int loglevel;
127 size_t nr_fields;
128 struct ustctl_field *fields;
129 char *model_emf_uri;
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130 struct lttng_ust_object_data *obj;
131 /*
132 * Flag for this channel if the metadata was dumped once during
133 * registration. 0 means no, 1 yes.
134 */
135 unsigned int metadata_dumped;
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136 /*
137 * Node in the ust-registry hash table. The event name is used to
138 * initialize the node and the event_name/signature for the match function.
139 */
7972aab2 140 struct lttng_ht_node_u64 node;
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141};
142
143/*
144 * Validate that the id has reached the maximum allowed or not.
145 *
146 * Return 0 if NOT else 1.
147 */
148static inline int ust_registry_is_max_id(uint32_t id)
149{
150 return (id == UINT32_MAX) ? 1 : 0;
151}
152
153/*
154 * Return next available event id and increment the used counter. The
155 * ust_registry_is_max_id function MUST be called before in order to validate
156 * if the maximum number of IDs have been reached. If not, it is safe to call
157 * this function.
158 *
159 * Return a unique channel ID. If max is reached, the used_event_id counter is
160 * returned.
161 */
162static inline uint32_t ust_registry_get_next_event_id(
163 struct ust_registry_channel *r)
164{
165 if (ust_registry_is_max_id(r->used_event_id)) {
166 return r->used_event_id;
167 }
168
169 r->used_event_id++;
170 return r->next_event_id++;
171}
172
173/*
174 * Return next available channel id and increment the used counter. The
175 * ust_registry_is_max_id function MUST be called before in order to validate
176 * if the maximum number of IDs have been reached. If not, it is safe to call
177 * this function.
178 *
179 * Return a unique channel ID. If max is reached, the used_channel_id counter
180 * is returned.
181 */
182static inline uint32_t ust_registry_get_next_chan_id(
183 struct ust_registry_session *r)
184{
185 if (ust_registry_is_max_id(r->used_channel_id)) {
186 return r->used_channel_id;
187 }
188
189 r->used_channel_id++;
190 return r->next_channel_id++;
191}
192
193/*
194 * Return registry event count. This is read atomically.
195 */
196static inline uint32_t ust_registry_get_event_count(
197 struct ust_registry_channel *r)
198{
199 return (uint32_t) uatomic_read(&r->used_event_id);
200}
201
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202#ifdef HAVE_LIBLTTNG_UST_CTL
203
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204void ust_registry_channel_destroy(struct ust_registry_session *session,
205 struct ust_registry_channel *chan);
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206struct ust_registry_channel *ust_registry_channel_find(
207 struct ust_registry_session *session, uint64_t key);
208int ust_registry_channel_add(struct ust_registry_session *session,
209 uint64_t key);
210void ust_registry_channel_del_free(struct ust_registry_session *session,
211 uint64_t key);
212
213int ust_registry_session_init(struct ust_registry_session **sessionp,
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214 struct ust_app *app,
215 uint32_t bits_per_long,
216 uint32_t uint8_t_alignment,
217 uint32_t uint16_t_alignment,
218 uint32_t uint32_t_alignment,
219 uint32_t uint64_t_alignment,
220 uint32_t long_alignment,
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221 int byte_order,
222 uint32_t major,
223 uint32_t minor);
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224void ust_registry_session_destroy(struct ust_registry_session *session);
225
226int ust_registry_create_event(struct ust_registry_session *session,
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227 uint64_t chan_key, int session_objd, int channel_objd, char *name,
228 char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
7972aab2 229 char *model_emf_uri, int buffer_type, uint32_t *event_id_p);
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230struct ust_registry_event *ust_registry_find_event(
231 struct ust_registry_channel *chan, char *name, char *sig);
232void ust_registry_destroy_event(struct ust_registry_channel *chan,
233 struct ust_registry_event *event);
234
235/* app can be NULL for registry shared across applications. */
236int ust_metadata_session_statedump(struct ust_registry_session *session,
af6142cf 237 struct ust_app *app, uint32_t major, uint32_t minor);
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238int ust_metadata_channel_statedump(struct ust_registry_session *session,
239 struct ust_registry_channel *chan);
240int ust_metadata_event_statedump(struct ust_registry_session *session,
241 struct ust_registry_channel *chan,
242 struct ust_registry_event *event);
243
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244#else /* HAVE_LIBLTTNG_UST_CTL */
245
246static inline
247void ust_registry_channel_destroy(struct ust_registry_session *session,
248 struct ust_registry_channel *chan)
249{}
250static inline
251struct ust_registry_channel *ust_registry_channel_find(
252 struct ust_registry_session *session, uint64_t key)
253{
254 return NULL;
255}
256static inline
257int ust_registry_channel_add(struct ust_registry_session *session,
258 uint64_t key)
259{
260 return 0;
261}
262static inline
263void ust_registry_channel_del_free(struct ust_registry_session *session,
264 uint64_t key)
265{}
266static inline
267int ust_registry_session_init(struct ust_registry_session **sessionp,
268 struct ust_app *app,
269 uint32_t bits_per_long,
270 uint32_t uint8_t_alignment,
271 uint32_t uint16_t_alignment,
272 uint32_t uint32_t_alignment,
273 uint32_t uint64_t_alignment,
274 uint32_t long_alignment,
275 int byte_order)
276{
277 return 0;
278}
279static inline
280void ust_registry_session_destroy(struct ust_registry_session *session)
281{}
282static inline
283int ust_registry_create_event(struct ust_registry_session *session,
284 uint64_t chan_key, int session_objd, int channel_objd, char *name,
285 char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
286 char *model_emf_uri, int buffer_type, uint32_t *event_id_p)
287{
288 return 0;
289}
290static inline
291struct ust_registry_event *ust_registry_find_event(
292 struct ust_registry_channel *chan, char *name, char *sig)
293{
294 return NULL;
295}
296static inline
297void ust_registry_destroy_event(struct ust_registry_channel *chan,
298 struct ust_registry_event *event)
299{}
300
301/* The app object can be NULL for registry shared across applications. */
302static inline
303int ust_metadata_session_statedump(struct ust_registry_session *session,
304 struct ust_app *app)
305{
306 return 0;
307}
308static inline
309int ust_metadata_channel_statedump(struct ust_registry_session *session,
310 struct ust_registry_channel *chan)
311{
312 return 0;
313}
314static inline
315int ust_metadata_event_statedump(struct ust_registry_session *session,
316 struct ust_registry_channel *chan,
317 struct ust_registry_event *event)
318{
319 return 0;
320}
321
322#endif /* HAVE_LIBLTTNG_UST_CTL */
323
d0b96690 324#endif /* LTTNG_UST_REGISTRY_H */
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