Commit | Line | Data |
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f99be407 | 1 | /* |
b27f8e75 | 2 | * Copyright (C) 2008-2011 Mathieu Desnoyers |
1f8b0dff | 3 | * Copyright (C) 2009 Pierre-Marc Fournier |
f99be407 | 4 | * |
34e4b7db PMF |
5 | * This library is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU Lesser General Public | |
f37142a4 MD |
7 | * License as published by the Free Software Foundation; |
8 | * version 2.1 of the License. | |
f99be407 | 9 | * |
34e4b7db | 10 | * This library is distributed in the hope that it will be useful, |
f99be407 | 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
34e4b7db PMF |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * Lesser General Public License for more details. | |
f99be407 | 14 | * |
34e4b7db PMF |
15 | * You should have received a copy of the GNU Lesser General Public |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
1f8b0dff PMF |
18 | * |
19 | * Ported to userspace by Pierre-Marc Fournier. | |
f99be407 | 20 | */ |
1f8b0dff | 21 | |
b0c4126f | 22 | #define _LGPL_SOURCE |
474d745f | 23 | #include <errno.h> |
b728d87e MD |
24 | #include <stdint.h> |
25 | #include <stddef.h> | |
33661f97 | 26 | #include <stdio.h> |
44c72f10 | 27 | |
b728d87e | 28 | #include <urcu/arch.h> |
10544ee8 | 29 | #include <lttng/urcu/urcu-ust.h> |
10c56168 | 30 | #include <urcu/hlist.h> |
edaa1431 | 31 | #include <urcu/uatomic.h> |
b728d87e | 32 | #include <urcu/compiler.h> |
c082d14b | 33 | #include <urcu/system.h> |
44c72f10 MD |
34 | |
35 | #include <lttng/tracepoint.h> | |
ff412fb5 | 36 | #include <lttng/ust-abi.h> /* for LTTNG_UST_SYM_NAME_LEN */ |
44c72f10 MD |
37 | |
38 | #include <usterr-signal-safe.h> | |
35897f8b | 39 | #include <helper.h> |
474d745f | 40 | |
23c8854a | 41 | #include "tracepoint-internal.h" |
7dd08bec | 42 | #include "lttng-tracer-core.h" |
596c4223 | 43 | #include "jhash.h" |
8f3f8c99 | 44 | #include "error.h" |
b0c4126f | 45 | |
5517d34d | 46 | /* Test compiler support for weak symbols with hidden visibility. */ |
b0e63efd MD |
47 | int __tracepoint_test_symbol1 __attribute__((weak, visibility("hidden"))); |
48 | void *__tracepoint_test_symbol2 __attribute__((weak, visibility("hidden"))); | |
49 | struct { | |
50 | char a[24]; | |
51 | } __tracepoint_test_symbol3 __attribute__((weak, visibility("hidden"))); | |
5517d34d | 52 | |
f99be407 PMF |
53 | /* Set to 1 to enable tracepoint debug output */ |
54 | static const int tracepoint_debug; | |
b27f8e75 | 55 | static int initialized; |
0fd0de10 FD |
56 | |
57 | /* | |
58 | * If tracepoint_destructors_state = 1, tracepoint destructors are | |
59 | * enabled. They are disabled otherwise. | |
60 | */ | |
61 | static int tracepoint_destructors_state = 1; | |
62 | ||
1a206094 | 63 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 64 | |
8792fbae MD |
65 | /* |
66 | * tracepoint_mutex nests inside UST mutex. | |
67 | * | |
68 | * Note about interaction with fork/clone: UST does not hold the | |
69 | * tracepoint mutex across fork/clone because it is either: | |
70 | * - nested within UST mutex, in which case holding the UST mutex across | |
71 | * fork/clone suffice, | |
72 | * - taken by a library constructor, which should never race with a | |
73 | * fork/clone if the application is expected to continue running with | |
74 | * the same memory layout (no following exec()). | |
75 | */ | |
76 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
77 | ||
efa2c591 MD |
78 | /* |
79 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 80 | * Protected by tracepoint mutex. |
efa2c591 | 81 | */ |
0222e121 | 82 | static CDS_LIST_HEAD(libs); |
474d745f | 83 | |
f99be407 | 84 | /* |
8792fbae | 85 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 86 | * the library list. |
8792fbae | 87 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
17dfb34b | 88 | * excepts calls to tracepoint_register_lib and |
8792fbae | 89 | * tracepoint_unregister_lib, which take the tracepoint mutex themselves. |
f99be407 | 90 | */ |
f99be407 PMF |
91 | |
92 | /* | |
93 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 94 | * Protected by tracepoint mutex. |
f99be407 | 95 | */ |
814f7df1 | 96 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 97 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 98 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 99 | |
b27f8e75 MD |
100 | static CDS_LIST_HEAD(old_probes); |
101 | static int need_update; | |
102 | ||
baa1e0bc MD |
103 | static CDS_LIST_HEAD(release_queue); |
104 | static int release_queue_need_update; | |
105 | ||
f99be407 PMF |
106 | /* |
107 | * Note about RCU : | |
108 | * It is used to to delay the free of multiple probes array until a quiescent | |
109 | * state is reached. | |
8792fbae | 110 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
111 | */ |
112 | struct tracepoint_entry { | |
10c56168 | 113 | struct cds_hlist_node hlist; |
1a206094 | 114 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 115 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 116 | int callsite_refcount; /* how many libs use this tracepoint */ |
2c05c691 FD |
117 | char *signature; |
118 | char *name; | |
f99be407 PMF |
119 | }; |
120 | ||
121 | struct tp_probes { | |
122 | union { | |
0222e121 | 123 | struct cds_list_head list; |
ade7037b MD |
124 | /* Field below only used for call_rcu scheme */ |
125 | /* struct rcu_head head; */ | |
f99be407 | 126 | } u; |
1a206094 | 127 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
128 | }; |
129 | ||
3469bbbe MD |
130 | /* |
131 | * Callsite hash table, containing the tracepoint call sites. | |
132 | * Protected by tracepoint mutex. | |
133 | */ | |
134 | #define CALLSITE_HASH_BITS 12 | |
135 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
136 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
137 | ||
138 | struct callsite_entry { | |
139 | struct cds_hlist_node hlist; /* hash table node */ | |
140 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 141 | struct lttng_ust_tracepoint *tp; |
2c05c691 | 142 | bool tp_entry_callsite_ref; /* Has a tp_entry took a ref on this callsite */ |
3469bbbe MD |
143 | }; |
144 | ||
5e6df7ea | 145 | /* coverity[+alloc] */ |
efa2c591 | 146 | static void *allocate_probes(int count) |
f99be407 | 147 | { |
1a206094 SM |
148 | struct tp_probes *p = |
149 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
150 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
151 | return p == NULL ? NULL : p->probes; |
152 | } | |
153 | ||
5e6df7ea | 154 | /* coverity[+free : arg-0] */ |
efa2c591 | 155 | static void release_probes(void *old) |
f99be407 PMF |
156 | { |
157 | if (old) { | |
b728d87e | 158 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 159 | struct tp_probes, probes[0]); |
10544ee8 | 160 | lttng_ust_synchronize_trace(); |
909bc43f | 161 | free(tp_probes); |
f99be407 PMF |
162 | } |
163 | } | |
164 | ||
165 | static void debug_print_probes(struct tracepoint_entry *entry) | |
166 | { | |
167 | int i; | |
168 | ||
9dec086e | 169 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
170 | return; |
171 | ||
9dec086e NC |
172 | for (i = 0; entry->probes[i].func; i++) |
173 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
174 | } |
175 | ||
176 | static void * | |
9dec086e | 177 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 178 | void (*probe)(void), void *data) |
f99be407 PMF |
179 | { |
180 | int nr_probes = 0; | |
1a206094 | 181 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 182 | |
d7509147 MD |
183 | if (!probe) { |
184 | WARN_ON(1); | |
185 | return ERR_PTR(-EINVAL); | |
186 | } | |
f99be407 | 187 | debug_print_probes(entry); |
9dec086e | 188 | old = entry->probes; |
f99be407 PMF |
189 | if (old) { |
190 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
191 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
192 | if (old[nr_probes].func == probe && | |
193 | old[nr_probes].data == data) | |
f99be407 PMF |
194 | return ERR_PTR(-EEXIST); |
195 | } | |
196 | /* + 2 : one for new probe, one for NULL func */ | |
197 | new = allocate_probes(nr_probes + 2); | |
198 | if (new == NULL) | |
199 | return ERR_PTR(-ENOMEM); | |
200 | if (old) | |
1a206094 SM |
201 | memcpy(new, old, |
202 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
203 | new[nr_probes].func = probe; |
204 | new[nr_probes].data = data; | |
205 | new[nr_probes + 1].func = NULL; | |
f99be407 | 206 | entry->refcount = nr_probes + 1; |
9dec086e | 207 | entry->probes = new; |
f99be407 PMF |
208 | debug_print_probes(entry); |
209 | return old; | |
210 | } | |
211 | ||
212 | static void * | |
fbdeb5ec MD |
213 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
214 | void (*probe)(void), void *data) | |
f99be407 PMF |
215 | { |
216 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 217 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 218 | |
9dec086e | 219 | old = entry->probes; |
f99be407 PMF |
220 | |
221 | if (!old) | |
222 | return ERR_PTR(-ENOENT); | |
223 | ||
224 | debug_print_probes(entry); | |
225 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
226 | if (probe) { |
227 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
228 | if (old[nr_probes].func == probe && | |
229 | old[nr_probes].data == data) | |
230 | nr_del++; | |
231 | } | |
f99be407 PMF |
232 | } |
233 | ||
234 | if (nr_probes - nr_del == 0) { | |
235 | /* N -> 0, (N > 1) */ | |
9dec086e | 236 | entry->probes = NULL; |
f99be407 PMF |
237 | entry->refcount = 0; |
238 | debug_print_probes(entry); | |
239 | return old; | |
240 | } else { | |
241 | int j = 0; | |
242 | /* N -> M, (N > 1, M > 0) */ | |
243 | /* + 1 for NULL */ | |
244 | new = allocate_probes(nr_probes - nr_del + 1); | |
245 | if (new == NULL) | |
246 | return ERR_PTR(-ENOMEM); | |
9dec086e | 247 | for (i = 0; old[i].func; i++) |
956c6fab | 248 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 249 | new[j++] = old[i]; |
9dec086e | 250 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 251 | entry->refcount = nr_probes - nr_del; |
9dec086e | 252 | entry->probes = new; |
f99be407 PMF |
253 | } |
254 | debug_print_probes(entry); | |
255 | return old; | |
256 | } | |
257 | ||
258 | /* | |
259 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 260 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
261 | * Returns NULL if not present. |
262 | */ | |
263 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
264 | { | |
10c56168 DG |
265 | struct cds_hlist_head *head; |
266 | struct cds_hlist_node *node; | |
f99be407 | 267 | struct tracepoint_entry *e; |
ff412fb5 MD |
268 | size_t name_len = strlen(name); |
269 | uint32_t hash; | |
f99be407 | 270 | |
ff412fb5 MD |
271 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
272 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
273 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
274 | } | |
275 | hash = jhash(name, name_len, 0); | |
f99be407 | 276 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 277 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 278 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) |
f99be407 PMF |
279 | return e; |
280 | } | |
281 | return NULL; | |
282 | } | |
283 | ||
284 | /* | |
285 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 286 | * tracepoint mutex held. |
f99be407 | 287 | */ |
67e5f391 MD |
288 | static struct tracepoint_entry *add_tracepoint(const char *name, |
289 | const char *signature) | |
f99be407 | 290 | { |
10c56168 DG |
291 | struct cds_hlist_head *head; |
292 | struct cds_hlist_node *node; | |
f99be407 | 293 | struct tracepoint_entry *e; |
ff412fb5 | 294 | size_t name_len = strlen(name); |
2c05c691 FD |
295 | size_t sig_len = strlen(signature); |
296 | size_t sig_off, name_off; | |
ff412fb5 | 297 | uint32_t hash; |
f99be407 | 298 | |
ff412fb5 MD |
299 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
300 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
301 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
302 | } | |
303 | hash = jhash(name, name_len, 0); | |
f99be407 | 304 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 305 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 306 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) { |
c1f20530 | 307 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
308 | return ERR_PTR(-EEXIST); /* Already there */ |
309 | } | |
310 | } | |
2c05c691 | 311 | |
f99be407 | 312 | /* |
2c05c691 FD |
313 | * Using zmalloc here to allocate a variable length elements: name and |
314 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 315 | */ |
2c05c691 FD |
316 | name_off = sizeof(struct tracepoint_entry); |
317 | sig_off = name_off + name_len + 1; | |
318 | ||
319 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1 + sig_len + 1); | |
f99be407 PMF |
320 | if (!e) |
321 | return ERR_PTR(-ENOMEM); | |
2c05c691 FD |
322 | e->name = (char *) e + name_off; |
323 | memcpy(e->name, name, name_len + 1); | |
ff412fb5 | 324 | e->name[name_len] = '\0'; |
2c05c691 FD |
325 | |
326 | e->signature = (char *) e + sig_off; | |
327 | memcpy(e->signature, signature, sig_len + 1); | |
328 | e->signature[sig_len] = '\0'; | |
329 | ||
9dec086e | 330 | e->probes = NULL; |
f99be407 | 331 | e->refcount = 0; |
8a7ad54b | 332 | e->callsite_refcount = 0; |
2c05c691 | 333 | |
10c56168 | 334 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
335 | return e; |
336 | } | |
337 | ||
338 | /* | |
339 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 340 | * tracepoint mutex held. |
f99be407 | 341 | */ |
efa2c591 | 342 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 343 | { |
10c56168 | 344 | cds_hlist_del(&e->hlist); |
909bc43f | 345 | free(e); |
f99be407 PMF |
346 | } |
347 | ||
348 | /* | |
349 | * Sets the probe callback corresponding to one tracepoint. | |
350 | */ | |
351 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 352 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 353 | { |
ff412fb5 | 354 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
355 | /* |
356 | * Check that signatures match before connecting a probe to a | |
357 | * tracepoint. Warn the user if they don't. | |
358 | */ | |
359 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
360 | static int warned = 0; | |
361 | ||
362 | /* Only print once, don't flood console. */ | |
363 | if (!warned) { | |
364 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
365 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
366 | elem->name, elem->signature, (*entry)->signature); | |
367 | warned = 1; | |
368 | } | |
369 | /* Don't accept connecting non-matching signatures. */ | |
370 | return; | |
371 | } | |
f99be407 PMF |
372 | |
373 | /* | |
0222e121 | 374 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
375 | * probe callbacks array is consistent before setting a pointer to it. |
376 | * This array is referenced by __DO_TRACE from | |
0222e121 | 377 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
378 | * is used. |
379 | */ | |
10544ee8 | 380 | lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 381 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
382 | } |
383 | ||
384 | /* | |
385 | * Disable a tracepoint and its probe callback. | |
386 | * Note: only waiting an RCU period after setting elem->call to the empty | |
387 | * function insures that the original callback is not used anymore. This insured | |
388 | * by preempt_disable around the call site. | |
389 | */ | |
1a206094 | 390 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 391 | { |
c082d14b | 392 | CMM_STORE_SHARED(elem->state, 0); |
10544ee8 | 393 | lttng_ust_rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
394 | } |
395 | ||
33f8ed87 MD |
396 | /* |
397 | * Add the callsite to the callsite hash table. Must be called with | |
398 | * tracepoint mutex held. | |
399 | */ | |
1a206094 | 400 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
401 | { |
402 | struct cds_hlist_head *head; | |
403 | struct callsite_entry *e; | |
404 | const char *name = tp->name; | |
405 | size_t name_len = strlen(name); | |
406 | uint32_t hash; | |
8a7ad54b | 407 | struct tracepoint_entry *tp_entry; |
33f8ed87 MD |
408 | |
409 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
410 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
411 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
412 | } | |
413 | hash = jhash(name, name_len, 0); | |
414 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
415 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 MD |
416 | if (!e) { |
417 | PERROR("Unable to add callsite for tracepoint \"%s\"", name); | |
418 | return; | |
419 | } | |
33f8ed87 MD |
420 | cds_hlist_add_head(&e->hlist, head); |
421 | e->tp = tp; | |
422 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b IJ |
423 | |
424 | tp_entry = get_tracepoint(name); | |
425 | if (!tp_entry) | |
426 | return; | |
427 | tp_entry->callsite_refcount++; | |
2c05c691 | 428 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
429 | } |
430 | ||
431 | /* | |
432 | * Remove the callsite from the callsite hash table and from lib | |
433 | * callsite list. Must be called with tracepoint mutex held. | |
434 | */ | |
435 | static void remove_callsite(struct callsite_entry *e) | |
436 | { | |
8a7ad54b IJ |
437 | struct tracepoint_entry *tp_entry; |
438 | ||
439 | tp_entry = get_tracepoint(e->tp->name); | |
440 | if (tp_entry) { | |
2c05c691 FD |
441 | if (e->tp_entry_callsite_ref) |
442 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
443 | if (tp_entry->callsite_refcount == 0) |
444 | disable_tracepoint(e->tp); | |
445 | } | |
33f8ed87 MD |
446 | cds_hlist_del(&e->hlist); |
447 | cds_list_del(&e->node); | |
448 | free(e); | |
449 | } | |
450 | ||
3469bbbe MD |
451 | /* |
452 | * Enable/disable all callsites based on the state of a specific | |
453 | * tracepoint entry. | |
454 | * Must be called with tracepoint mutex held. | |
455 | */ | |
456 | static void tracepoint_sync_callsites(const char *name) | |
457 | { | |
458 | struct cds_hlist_head *head; | |
459 | struct cds_hlist_node *node; | |
460 | struct callsite_entry *e; | |
461 | size_t name_len = strlen(name); | |
462 | uint32_t hash; | |
463 | struct tracepoint_entry *tp_entry; | |
464 | ||
465 | tp_entry = get_tracepoint(name); | |
466 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
467 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
468 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
469 | } | |
470 | hash = jhash(name, name_len, 0); | |
471 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
472 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 473 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe MD |
474 | |
475 | if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1)) | |
476 | continue; | |
477 | if (tp_entry) { | |
2c05c691 FD |
478 | if (!e->tp_entry_callsite_ref) { |
479 | tp_entry->callsite_refcount++; | |
480 | e->tp_entry_callsite_ref = true; | |
481 | } | |
3469bbbe MD |
482 | set_tracepoint(&tp_entry, tp, |
483 | !!tp_entry->refcount); | |
484 | } else { | |
485 | disable_tracepoint(tp); | |
2c05c691 | 486 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
487 | } |
488 | } | |
489 | } | |
490 | ||
f99be407 PMF |
491 | /** |
492 | * tracepoint_update_probe_range - Update a probe range | |
493 | * @begin: beginning of the range | |
494 | * @end: end of the range | |
495 | * | |
496 | * Updates the probe callback corresponding to a range of tracepoints. | |
497 | */ | |
b27f8e75 | 498 | static |
1a206094 SM |
499 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
500 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 501 | { |
1a206094 | 502 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
503 | struct tracepoint_entry *mark_entry; |
504 | ||
f99be407 | 505 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
506 | if (!*iter) |
507 | continue; /* skip dummy */ | |
f218ff28 MD |
508 | if (!(*iter)->name) { |
509 | disable_tracepoint(*iter); | |
9dec086e NC |
510 | continue; |
511 | } | |
f218ff28 | 512 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 513 | if (mark_entry) { |
f218ff28 | 514 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
515 | !!mark_entry->refcount); |
516 | } else { | |
f218ff28 | 517 | disable_tracepoint(*iter); |
f99be407 PMF |
518 | } |
519 | } | |
f99be407 PMF |
520 | } |
521 | ||
5da10905 | 522 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 523 | { |
5da10905 MD |
524 | tracepoint_update_probe_range(lib->tracepoints_start, |
525 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
526 | } |
527 | ||
3469bbbe MD |
528 | static void lib_register_callsites(struct tracepoint_lib *lib) |
529 | { | |
1a206094 SM |
530 | struct lttng_ust_tracepoint * const *begin; |
531 | struct lttng_ust_tracepoint * const *end; | |
532 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
533 | |
534 | begin = lib->tracepoints_start; | |
535 | end = lib->tracepoints_start + lib->tracepoints_count; | |
536 | ||
537 | for (iter = begin; iter < end; iter++) { | |
538 | if (!*iter) | |
539 | continue; /* skip dummy */ | |
540 | if (!(*iter)->name) { | |
541 | continue; | |
542 | } | |
60d87029 | 543 | add_callsite(lib, *iter); |
3469bbbe MD |
544 | } |
545 | } | |
546 | ||
547 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
548 | { | |
549 | struct callsite_entry *callsite, *tmp; | |
550 | ||
551 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
552 | remove_callsite(callsite); | |
553 | } | |
554 | ||
f99be407 PMF |
555 | /* |
556 | * Update probes, removing the faulty probes. | |
557 | */ | |
558 | static void tracepoint_update_probes(void) | |
559 | { | |
5da10905 MD |
560 | struct tracepoint_lib *lib; |
561 | ||
b27f8e75 | 562 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
563 | cds_list_for_each_entry(lib, &libs, list) |
564 | lib_update_tracepoints(lib); | |
f99be407 PMF |
565 | } |
566 | ||
1a206094 | 567 | static struct lttng_ust_tracepoint_probe * |
fbdeb5ec | 568 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 569 | const char *signature) |
f99be407 PMF |
570 | { |
571 | struct tracepoint_entry *entry; | |
1a206094 | 572 | struct lttng_ust_tracepoint_probe *old; |
f99be407 PMF |
573 | |
574 | entry = get_tracepoint(name); | |
2c05c691 FD |
575 | if (entry) { |
576 | if (strcmp(entry->signature, signature) != 0) { | |
577 | ERR("Tracepoint and probe signature do not match."); | |
578 | return ERR_PTR(-EINVAL); | |
579 | } | |
580 | } else { | |
67e5f391 | 581 | entry = add_tracepoint(name, signature); |
f99be407 | 582 | if (IS_ERR(entry)) |
1a206094 | 583 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 584 | } |
9dec086e | 585 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
586 | if (IS_ERR(old) && !entry->refcount) |
587 | remove_tracepoint(entry); | |
588 | return old; | |
589 | } | |
590 | ||
baa1e0bc MD |
591 | static void tracepoint_release_queue_add_old_probes(void *old) |
592 | { | |
593 | release_queue_need_update = 1; | |
594 | if (old) { | |
595 | struct tp_probes *tp_probes = caa_container_of(old, | |
596 | struct tp_probes, probes[0]); | |
597 | cds_list_add(&tp_probes->u.list, &release_queue); | |
598 | } | |
599 | } | |
600 | ||
f99be407 | 601 | /** |
81614639 | 602 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
603 | * @name: tracepoint name |
604 | * @probe: probe handler | |
605 | * | |
606 | * Returns 0 if ok, error value on error. | |
607 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 608 | * Called with the tracepoint mutex held. |
f99be407 | 609 | */ |
fbdeb5ec MD |
610 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
611 | void *data, const char *signature) | |
f99be407 PMF |
612 | { |
613 | void *old; | |
8792fbae | 614 | int ret = 0; |
f99be407 | 615 | |
05780d81 MD |
616 | DBG("Registering probe to tracepoint %s", name); |
617 | ||
8792fbae | 618 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 619 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
620 | if (IS_ERR(old)) { |
621 | ret = PTR_ERR(old); | |
622 | goto end; | |
623 | } | |
f99be407 | 624 | |
3469bbbe | 625 | tracepoint_sync_callsites(name); |
f99be407 | 626 | release_probes(old); |
8792fbae MD |
627 | end: |
628 | pthread_mutex_unlock(&tracepoint_mutex); | |
629 | return ret; | |
f99be407 | 630 | } |
f99be407 | 631 | |
baa1e0bc MD |
632 | /* |
633 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
634 | * calling __tracepoint_probe_register_queue_release() one or multiple | |
635 | * times to ensure it does not leak memory. | |
636 | */ | |
637 | int __tracepoint_probe_register_queue_release(const char *name, | |
638 | void (*probe)(void), void *data, const char *signature) | |
639 | { | |
640 | void *old; | |
641 | int ret = 0; | |
642 | ||
643 | DBG("Registering probe to tracepoint %s. Queuing release.", name); | |
644 | ||
645 | pthread_mutex_lock(&tracepoint_mutex); | |
646 | old = tracepoint_add_probe(name, probe, data, signature); | |
647 | if (IS_ERR(old)) { | |
648 | ret = PTR_ERR(old); | |
649 | goto end; | |
650 | } | |
651 | ||
652 | tracepoint_sync_callsites(name); | |
653 | tracepoint_release_queue_add_old_probes(old); | |
654 | end: | |
655 | pthread_mutex_unlock(&tracepoint_mutex); | |
656 | return ret; | |
657 | } | |
658 | ||
fbdeb5ec MD |
659 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
660 | void *data) | |
f99be407 PMF |
661 | { |
662 | struct tracepoint_entry *entry; | |
663 | void *old; | |
664 | ||
665 | entry = get_tracepoint(name); | |
666 | if (!entry) | |
667 | return ERR_PTR(-ENOENT); | |
9dec086e | 668 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
669 | if (IS_ERR(old)) |
670 | return old; | |
671 | if (!entry->refcount) | |
672 | remove_tracepoint(entry); | |
673 | return old; | |
674 | } | |
675 | ||
676 | /** | |
677 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
678 | * @name: tracepoint name | |
679 | * @probe: probe function pointer | |
9dec086e | 680 | * @probe: probe data pointer |
f99be407 | 681 | */ |
fbdeb5ec MD |
682 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
683 | void *data) | |
f99be407 PMF |
684 | { |
685 | void *old; | |
8792fbae | 686 | int ret = 0; |
f99be407 | 687 | |
05780d81 MD |
688 | DBG("Un-registering probe from tracepoint %s", name); |
689 | ||
8792fbae | 690 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 691 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
692 | if (IS_ERR(old)) { |
693 | ret = PTR_ERR(old); | |
694 | goto end; | |
695 | } | |
3469bbbe | 696 | tracepoint_sync_callsites(name); |
f99be407 | 697 | release_probes(old); |
8792fbae MD |
698 | end: |
699 | pthread_mutex_unlock(&tracepoint_mutex); | |
700 | return ret; | |
f99be407 | 701 | } |
f99be407 | 702 | |
baa1e0bc MD |
703 | /* |
704 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
705 | * calling __tracepoint_probe_unregister_queue_release() one or multiple | |
706 | * times to ensure it does not leak memory. | |
707 | */ | |
708 | int __tracepoint_probe_unregister_queue_release(const char *name, | |
709 | void (*probe)(void), void *data) | |
710 | { | |
711 | void *old; | |
712 | int ret = 0; | |
713 | ||
714 | DBG("Un-registering probe from tracepoint %s. Queuing release.", name); | |
715 | ||
716 | pthread_mutex_lock(&tracepoint_mutex); | |
717 | old = tracepoint_remove_probe(name, probe, data); | |
718 | if (IS_ERR(old)) { | |
719 | ret = PTR_ERR(old); | |
720 | goto end; | |
721 | } | |
722 | tracepoint_sync_callsites(name); | |
723 | tracepoint_release_queue_add_old_probes(old); | |
724 | end: | |
725 | pthread_mutex_unlock(&tracepoint_mutex); | |
726 | return ret; | |
727 | } | |
728 | ||
729 | void __tracepoint_probe_prune_release_queue(void) | |
730 | { | |
731 | CDS_LIST_HEAD(release_probes); | |
732 | struct tp_probes *pos, *next; | |
733 | ||
734 | DBG("Release queue of unregistered tracepoint probes."); | |
735 | ||
736 | pthread_mutex_lock(&tracepoint_mutex); | |
737 | if (!release_queue_need_update) | |
738 | goto end; | |
739 | if (!cds_list_empty(&release_queue)) | |
740 | cds_list_replace_init(&release_queue, &release_probes); | |
741 | release_queue_need_update = 0; | |
742 | ||
743 | /* Wait for grace period between all sync_callsites and free. */ | |
10544ee8 | 744 | lttng_ust_synchronize_trace(); |
baa1e0bc MD |
745 | |
746 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
747 | cds_list_del(&pos->u.list); | |
748 | free(pos); | |
749 | } | |
750 | end: | |
751 | pthread_mutex_unlock(&tracepoint_mutex); | |
752 | } | |
753 | ||
f99be407 PMF |
754 | static void tracepoint_add_old_probes(void *old) |
755 | { | |
756 | need_update = 1; | |
757 | if (old) { | |
b728d87e | 758 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 759 | struct tp_probes, probes[0]); |
0222e121 | 760 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
761 | } |
762 | } | |
763 | ||
764 | /** | |
765 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
766 | * @name: tracepoint name | |
767 | * @probe: probe handler | |
768 | * | |
769 | * caller must call tracepoint_probe_update_all() | |
770 | */ | |
fbdeb5ec | 771 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 772 | void *data, const char *signature) |
f99be407 PMF |
773 | { |
774 | void *old; | |
8792fbae | 775 | int ret = 0; |
f99be407 | 776 | |
8792fbae | 777 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 778 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 779 | if (IS_ERR(old)) { |
8792fbae MD |
780 | ret = PTR_ERR(old); |
781 | goto end; | |
f99be407 PMF |
782 | } |
783 | tracepoint_add_old_probes(old); | |
8792fbae MD |
784 | end: |
785 | pthread_mutex_unlock(&tracepoint_mutex); | |
786 | return ret; | |
f99be407 | 787 | } |
f99be407 PMF |
788 | |
789 | /** | |
790 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
791 | * @name: tracepoint name | |
792 | * @probe: probe function pointer | |
793 | * | |
794 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 795 | * Called with the tracepoint mutex held. |
f99be407 | 796 | */ |
fbdeb5ec | 797 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 798 | void *data) |
f99be407 PMF |
799 | { |
800 | void *old; | |
8792fbae | 801 | int ret = 0; |
f99be407 | 802 | |
05780d81 MD |
803 | DBG("Un-registering probe from tracepoint %s", name); |
804 | ||
8792fbae | 805 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 806 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 807 | if (IS_ERR(old)) { |
8792fbae MD |
808 | ret = PTR_ERR(old); |
809 | goto end; | |
f99be407 PMF |
810 | } |
811 | tracepoint_add_old_probes(old); | |
8792fbae MD |
812 | end: |
813 | pthread_mutex_unlock(&tracepoint_mutex); | |
814 | return ret; | |
f99be407 | 815 | } |
f99be407 PMF |
816 | |
817 | /** | |
818 | * tracepoint_probe_update_all - update tracepoints | |
819 | */ | |
820 | void tracepoint_probe_update_all(void) | |
821 | { | |
0222e121 | 822 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
823 | struct tp_probes *pos, *next; |
824 | ||
8792fbae | 825 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 826 | if (!need_update) { |
8792fbae | 827 | goto end; |
f99be407 | 828 | } |
0222e121 MD |
829 | if (!cds_list_empty(&old_probes)) |
830 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 831 | need_update = 0; |
f99be407 PMF |
832 | |
833 | tracepoint_update_probes(); | |
baa1e0bc | 834 | /* Wait for grace period between update_probes and free. */ |
10544ee8 | 835 | lttng_ust_synchronize_trace(); |
0222e121 MD |
836 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
837 | cds_list_del(&pos->u.list); | |
909bc43f | 838 | free(pos); |
f99be407 | 839 | } |
8792fbae MD |
840 | end: |
841 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 842 | } |
f99be407 | 843 | |
1a206094 | 844 | void tracepoint_set_new_tracepoint_cb(void (*cb)(struct lttng_ust_tracepoint *)) |
474d745f PMF |
845 | { |
846 | new_tracepoint_cb = cb; | |
847 | } | |
f99be407 | 848 | |
1a206094 SM |
849 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
850 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 851 | { |
f218ff28 | 852 | if (new_tracepoint_cb) { |
1a206094 | 853 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 854 | |
b27f8e75 | 855 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
856 | if (*t) |
857 | new_tracepoint_cb(*t); | |
474d745f PMF |
858 | } |
859 | } | |
f99be407 | 860 | } |
f99be407 | 861 | |
10544ee8 MD |
862 | /* |
863 | * tracepoint_{un,}register_lib is meant to be looked up by instrumented | |
864 | * applications through dlsym(). If found, those can register their | |
865 | * tracepoints, else those tracepoints will not be available for | |
866 | * tracing. The number at the end of those symbols acts as a major | |
867 | * version for tracepoints. | |
868 | * | |
869 | * Older instrumented applications should still work with newer | |
870 | * liblttng-ust, but it is fine that instrumented applications compiled | |
871 | * against recent liblttng-ust headers require a recent liblttng-ust | |
872 | * runtime for those tracepoints to be taken into account. | |
873 | */ | |
ae14f822 | 874 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
10544ee8 | 875 | int tracepoints_count) |
474d745f | 876 | { |
b467f7a7 | 877 | struct tracepoint_lib *pl, *iter; |
474d745f | 878 | |
edaa1431 MD |
879 | init_tracepoint(); |
880 | ||
1dba3e6c | 881 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
882 | if (!pl) { |
883 | PERROR("Unable to register tracepoint lib"); | |
884 | return -1; | |
885 | } | |
474d745f PMF |
886 | pl->tracepoints_start = tracepoints_start; |
887 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 888 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 889 | |
8792fbae | 890 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
891 | /* |
892 | * We sort the libs by struct lib pointer address. | |
893 | */ | |
894 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
895 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
896 | if (iter < pl) { | |
897 | /* We belong to the location right after iter. */ | |
898 | cds_list_add(&pl->list, &iter->list); | |
899 | goto lib_added; | |
900 | } | |
901 | } | |
902 | /* We should be added at the head of the list */ | |
0222e121 | 903 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 904 | lib_added: |
474d745f | 905 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 906 | lib_register_callsites(pl); |
5da10905 | 907 | lib_update_tracepoints(pl); |
8792fbae | 908 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 909 | |
1fcf7ad7 MD |
910 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
911 | tracepoints_start, tracepoints_count); | |
05780d81 MD |
912 | if (ust_debug()) { |
913 | int i; | |
914 | ||
915 | for (i = 0; i < tracepoints_count; i++) { | |
916 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
917 | } | |
918 | } | |
9dec086e | 919 | |
474d745f PMF |
920 | return 0; |
921 | } | |
922 | ||
ae14f822 | 923 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) |
474d745f | 924 | { |
24b6668c PMF |
925 | struct tracepoint_lib *lib; |
926 | ||
8792fbae | 927 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 928 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
929 | if (lib->tracepoints_start != tracepoints_start) |
930 | continue; | |
1622ba22 | 931 | |
3469bbbe MD |
932 | cds_list_del(&lib->list); |
933 | /* | |
8a7ad54b IJ |
934 | * Unregistering a callsite also decreases the |
935 | * callsite reference count of the corresponding | |
936 | * tracepoint, and disables the tracepoint if | |
937 | * the reference count drops to zero. | |
3469bbbe | 938 | */ |
3469bbbe MD |
939 | lib_unregister_callsites(lib); |
940 | DBG("just unregistered a tracepoints section from %p", | |
941 | lib->tracepoints_start); | |
942 | free(lib); | |
943 | break; | |
24b6668c | 944 | } |
8792fbae | 945 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
946 | return 0; |
947 | } | |
b27f8e75 | 948 | |
5517d34d MD |
949 | /* |
950 | * Report in debug message whether the compiler correctly supports weak | |
951 | * hidden symbols. This test checks that the address associated with two | |
952 | * weak symbols with hidden visibility is the same when declared within | |
953 | * two compile units part of the same module. | |
954 | */ | |
955 | static void check_weak_hidden(void) | |
956 | { | |
b0e63efd MD |
957 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
958 | &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? | |
959 | "SAME address" : | |
960 | "DIFFERENT addresses"); | |
961 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
962 | &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? | |
963 | "SAME address" : | |
964 | "DIFFERENT addresses"); | |
965 | DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.", | |
966 | &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? | |
967 | "SAME address" : | |
968 | "DIFFERENT addresses"); | |
5517d34d MD |
969 | } |
970 | ||
edaa1431 | 971 | void init_tracepoint(void) |
b27f8e75 | 972 | { |
edaa1431 MD |
973 | if (uatomic_xchg(&initialized, 1) == 1) |
974 | return; | |
5e96a467 | 975 | init_usterr(); |
5517d34d | 976 | check_weak_hidden(); |
b27f8e75 MD |
977 | } |
978 | ||
edaa1431 | 979 | void exit_tracepoint(void) |
b27f8e75 | 980 | { |
17dfb34b | 981 | initialized = 0; |
b27f8e75 | 982 | } |
40b2b5a4 MD |
983 | |
984 | /* | |
985 | * Create the wrapper symbols. | |
986 | */ | |
10544ee8 MD |
987 | #undef tp_rcu_read_lock |
988 | #undef tp_rcu_read_unlock | |
989 | #undef tp_rcu_dereference | |
40b2b5a4 | 990 | |
10544ee8 | 991 | void tp_rcu_read_lock(void) |
40b2b5a4 | 992 | { |
10544ee8 | 993 | lttng_ust_urcu_read_lock(); |
40b2b5a4 MD |
994 | } |
995 | ||
10544ee8 | 996 | void tp_rcu_read_unlock(void) |
40b2b5a4 | 997 | { |
10544ee8 | 998 | lttng_ust_urcu_read_unlock(); |
40b2b5a4 MD |
999 | } |
1000 | ||
10544ee8 | 1001 | void *tp_rcu_dereference_sym(void *p) |
40b2b5a4 | 1002 | { |
10544ee8 | 1003 | return lttng_ust_rcu_dereference(p); |
40b2b5a4 | 1004 | } |
0fd0de10 FD |
1005 | |
1006 | /* | |
1007 | * Programs that have threads that survive after they exit, and therefore call | |
1008 | * library destructors, should disable the tracepoint destructors by calling | |
1009 | * tp_disable_destructors(). This will leak the tracepoint | |
1010 | * instrumentation library shared object, leaving its teardown to the operating | |
1011 | * system process teardown. | |
1012 | * | |
1013 | * To access and/or modify this value, users need to use a combination of | |
1014 | * dlopen(3) and dlsym(3) to get an handle on the | |
1015 | * tp_disable_destructors and tp_get_destructors_state symbols below. | |
1016 | */ | |
1017 | void tp_disable_destructors(void) | |
1018 | { | |
1019 | uatomic_set(&tracepoint_destructors_state, 0); | |
1020 | } | |
1021 | ||
1022 | /* | |
1023 | * Returns 1 if the destructors are enabled and should be executed. | |
1024 | * Returns 0 if the destructors are disabled. | |
1025 | */ | |
1026 | int tp_get_destructors_state(void) | |
1027 | { | |
1028 | return uatomic_read(&tracepoint_destructors_state); | |
1029 | } | |
10544ee8 MD |
1030 | |
1031 | void lttng_ust_synchronize_trace(void) | |
1032 | { | |
1033 | lttng_ust_urcu_synchronize_rcu(); | |
10544ee8 | 1034 | } |