Commit | Line | Data |
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f99be407 | 1 | /* |
c0c0989a MJ |
2 | * SPDX-License-Identifier: LGPL-2.1-only |
3 | * | |
b27f8e75 | 4 | * Copyright (C) 2008-2011 Mathieu Desnoyers |
1f8b0dff | 5 | * Copyright (C) 2009 Pierre-Marc Fournier |
f99be407 | 6 | * |
1f8b0dff | 7 | * Ported to userspace by Pierre-Marc Fournier. |
f99be407 | 8 | */ |
1f8b0dff | 9 | |
b0c4126f | 10 | #define _LGPL_SOURCE |
474d745f | 11 | #include <errno.h> |
b728d87e MD |
12 | #include <stdint.h> |
13 | #include <stddef.h> | |
33661f97 | 14 | #include <stdio.h> |
44c72f10 | 15 | |
b728d87e | 16 | #include <urcu/arch.h> |
10544ee8 | 17 | #include <lttng/urcu/urcu-ust.h> |
10c56168 | 18 | #include <urcu/hlist.h> |
edaa1431 | 19 | #include <urcu/uatomic.h> |
b728d87e | 20 | #include <urcu/compiler.h> |
c082d14b | 21 | #include <urcu/system.h> |
44c72f10 MD |
22 | |
23 | #include <lttng/tracepoint.h> | |
fd17d7ce | 24 | #include <lttng/ust-abi.h> /* for LTTNG_UST_ABI_SYM_NAME_LEN */ |
fca97dfd | 25 | #include <lttng/ust-common.h> |
44c72f10 | 26 | |
9d315d6d MJ |
27 | #include "common/logging.h" |
28 | #include "common/macros.h" | |
474d745f | 29 | |
8f51c684 MJ |
30 | #include "lib/lttng-ust-tracepoint/tracepoint.h" |
31 | #include "common/tracepoint.h" | |
e58e5ad5 | 32 | #include "common/jhash.h" |
9c4fe08d | 33 | #include "common/err-ptr.h" |
b0c4126f | 34 | |
5517d34d | 35 | /* Test compiler support for weak symbols with hidden visibility. */ |
0274f7f2 MJ |
36 | int lttng_ust_tracepoint_test_symbol1 __attribute__((weak, visibility("hidden"))); |
37 | void *lttng_ust_tracepoint_test_symbol2 __attribute__((weak, visibility("hidden"))); | |
b0e63efd MD |
38 | struct { |
39 | char a[24]; | |
0274f7f2 | 40 | } lttng_ust_tracepoint_test_symbol3 __attribute__((weak, visibility("hidden"))); |
5517d34d | 41 | |
f99be407 PMF |
42 | /* Set to 1 to enable tracepoint debug output */ |
43 | static const int tracepoint_debug; | |
b27f8e75 | 44 | static int initialized; |
0fd0de10 FD |
45 | |
46 | /* | |
47 | * If tracepoint_destructors_state = 1, tracepoint destructors are | |
48 | * enabled. They are disabled otherwise. | |
49 | */ | |
50 | static int tracepoint_destructors_state = 1; | |
51 | ||
1a206094 | 52 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 53 | |
8792fbae MD |
54 | /* |
55 | * tracepoint_mutex nests inside UST mutex. | |
56 | * | |
57 | * Note about interaction with fork/clone: UST does not hold the | |
58 | * tracepoint mutex across fork/clone because it is either: | |
59 | * - nested within UST mutex, in which case holding the UST mutex across | |
60 | * fork/clone suffice, | |
61 | * - taken by a library constructor, which should never race with a | |
62 | * fork/clone if the application is expected to continue running with | |
63 | * the same memory layout (no following exec()). | |
64 | */ | |
65 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
66 | ||
efa2c591 MD |
67 | /* |
68 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 69 | * Protected by tracepoint mutex. |
efa2c591 | 70 | */ |
0222e121 | 71 | static CDS_LIST_HEAD(libs); |
474d745f | 72 | |
f99be407 | 73 | /* |
8792fbae | 74 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 75 | * the library list. |
8792fbae | 76 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
17dfb34b | 77 | * excepts calls to tracepoint_register_lib and |
8792fbae | 78 | * tracepoint_unregister_lib, which take the tracepoint mutex themselves. |
f99be407 | 79 | */ |
f99be407 PMF |
80 | |
81 | /* | |
82 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 83 | * Protected by tracepoint mutex. |
f99be407 | 84 | */ |
814f7df1 | 85 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 86 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 87 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 88 | |
b27f8e75 MD |
89 | static CDS_LIST_HEAD(old_probes); |
90 | static int need_update; | |
91 | ||
baa1e0bc MD |
92 | static CDS_LIST_HEAD(release_queue); |
93 | static int release_queue_need_update; | |
94 | ||
f99be407 PMF |
95 | /* |
96 | * Note about RCU : | |
97 | * It is used to to delay the free of multiple probes array until a quiescent | |
98 | * state is reached. | |
8792fbae | 99 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
100 | */ |
101 | struct tracepoint_entry { | |
10c56168 | 102 | struct cds_hlist_node hlist; |
1a206094 | 103 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 104 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 105 | int callsite_refcount; /* how many libs use this tracepoint */ |
2c05c691 | 106 | char *signature; |
34f7f142 MD |
107 | char *provider_name; |
108 | char *event_name; | |
f99be407 PMF |
109 | }; |
110 | ||
111 | struct tp_probes { | |
112 | union { | |
0222e121 | 113 | struct cds_list_head list; |
ade7037b MD |
114 | /* Field below only used for call_rcu scheme */ |
115 | /* struct rcu_head head; */ | |
f99be407 | 116 | } u; |
1a206094 | 117 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
118 | }; |
119 | ||
3469bbbe MD |
120 | /* |
121 | * Callsite hash table, containing the tracepoint call sites. | |
122 | * Protected by tracepoint mutex. | |
123 | */ | |
124 | #define CALLSITE_HASH_BITS 12 | |
125 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
126 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
127 | ||
128 | struct callsite_entry { | |
129 | struct cds_hlist_node hlist; /* hash table node */ | |
130 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 131 | struct lttng_ust_tracepoint *tp; |
2c05c691 | 132 | bool tp_entry_callsite_ref; /* Has a tp_entry took a ref on this callsite */ |
3469bbbe MD |
133 | }; |
134 | ||
81b16412 MD |
135 | lttng_ust_static_assert(LTTNG_UST_TRACEPOINT_NAME_LEN_MAX == LTTNG_UST_ABI_SYM_NAME_LEN, |
136 | "Tracepoint name max length mismatch between UST ABI and tracepoint API", | |
137 | Tracepoint_name_max_length_mismatch); | |
138 | ||
34f7f142 MD |
139 | static |
140 | bool lttng_ust_tp_validate_event_name(const struct lttng_ust_tracepoint *tp) | |
141 | { | |
142 | if (strlen(tp->provider_name) + 1 + | |
143 | strlen(tp->event_name) >= LTTNG_UST_TRACEPOINT_NAME_LEN_MAX) | |
144 | return false; | |
145 | return true; | |
146 | } | |
147 | ||
5e6df7ea | 148 | /* coverity[+alloc] */ |
efa2c591 | 149 | static void *allocate_probes(int count) |
f99be407 | 150 | { |
1a206094 SM |
151 | struct tp_probes *p = |
152 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
153 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
154 | return p == NULL ? NULL : p->probes; |
155 | } | |
156 | ||
5e6df7ea | 157 | /* coverity[+free : arg-0] */ |
efa2c591 | 158 | static void release_probes(void *old) |
f99be407 PMF |
159 | { |
160 | if (old) { | |
b728d87e | 161 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 162 | struct tp_probes, probes[0]); |
b653ddc1 | 163 | lttng_ust_urcu_synchronize_rcu(); |
909bc43f | 164 | free(tp_probes); |
f99be407 PMF |
165 | } |
166 | } | |
167 | ||
168 | static void debug_print_probes(struct tracepoint_entry *entry) | |
169 | { | |
170 | int i; | |
171 | ||
9dec086e | 172 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
173 | return; |
174 | ||
9dec086e NC |
175 | for (i = 0; entry->probes[i].func; i++) |
176 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
177 | } |
178 | ||
179 | static void * | |
9dec086e | 180 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 181 | void (*probe)(void), void *data) |
f99be407 PMF |
182 | { |
183 | int nr_probes = 0; | |
1a206094 | 184 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 185 | |
d7509147 MD |
186 | if (!probe) { |
187 | WARN_ON(1); | |
188 | return ERR_PTR(-EINVAL); | |
189 | } | |
f99be407 | 190 | debug_print_probes(entry); |
9dec086e | 191 | old = entry->probes; |
f99be407 PMF |
192 | if (old) { |
193 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
194 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
195 | if (old[nr_probes].func == probe && | |
196 | old[nr_probes].data == data) | |
f99be407 PMF |
197 | return ERR_PTR(-EEXIST); |
198 | } | |
199 | /* + 2 : one for new probe, one for NULL func */ | |
200 | new = allocate_probes(nr_probes + 2); | |
201 | if (new == NULL) | |
202 | return ERR_PTR(-ENOMEM); | |
203 | if (old) | |
1a206094 SM |
204 | memcpy(new, old, |
205 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
206 | new[nr_probes].func = probe; |
207 | new[nr_probes].data = data; | |
208 | new[nr_probes + 1].func = NULL; | |
f99be407 | 209 | entry->refcount = nr_probes + 1; |
9dec086e | 210 | entry->probes = new; |
f99be407 PMF |
211 | debug_print_probes(entry); |
212 | return old; | |
213 | } | |
214 | ||
215 | static void * | |
fbdeb5ec MD |
216 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
217 | void (*probe)(void), void *data) | |
f99be407 PMF |
218 | { |
219 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 220 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 221 | |
9dec086e | 222 | old = entry->probes; |
f99be407 PMF |
223 | |
224 | if (!old) | |
225 | return ERR_PTR(-ENOENT); | |
226 | ||
227 | debug_print_probes(entry); | |
228 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
229 | if (probe) { |
230 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
231 | if (old[nr_probes].func == probe && | |
232 | old[nr_probes].data == data) | |
233 | nr_del++; | |
234 | } | |
f99be407 PMF |
235 | } |
236 | ||
237 | if (nr_probes - nr_del == 0) { | |
238 | /* N -> 0, (N > 1) */ | |
9dec086e | 239 | entry->probes = NULL; |
f99be407 PMF |
240 | entry->refcount = 0; |
241 | debug_print_probes(entry); | |
242 | return old; | |
243 | } else { | |
244 | int j = 0; | |
245 | /* N -> M, (N > 1, M > 0) */ | |
246 | /* + 1 for NULL */ | |
247 | new = allocate_probes(nr_probes - nr_del + 1); | |
248 | if (new == NULL) | |
249 | return ERR_PTR(-ENOMEM); | |
9dec086e | 250 | for (i = 0; old[i].func; i++) |
956c6fab | 251 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 252 | new[j++] = old[i]; |
9dec086e | 253 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 254 | entry->refcount = nr_probes - nr_del; |
9dec086e | 255 | entry->probes = new; |
f99be407 PMF |
256 | } |
257 | debug_print_probes(entry); | |
258 | return old; | |
259 | } | |
260 | ||
261 | /* | |
262 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 263 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
264 | * Returns NULL if not present. |
265 | */ | |
34f7f142 | 266 | static struct tracepoint_entry *get_tracepoint(const char *provider_name, const char *event_name) |
f99be407 | 267 | { |
10c56168 DG |
268 | struct cds_hlist_head *head; |
269 | struct cds_hlist_node *node; | |
f99be407 | 270 | struct tracepoint_entry *e; |
ff412fb5 | 271 | uint32_t hash; |
f99be407 | 272 | |
34f7f142 MD |
273 | hash = jhash(provider_name, strlen(provider_name), 0) ^ |
274 | jhash(event_name, strlen(event_name), 0); | |
f99be407 | 275 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 276 | cds_hlist_for_each_entry(e, node, head, hlist) { |
34f7f142 | 277 | if (!strcmp(event_name, e->event_name) && !strcmp(provider_name, e->provider_name)) |
f99be407 PMF |
278 | return e; |
279 | } | |
280 | return NULL; | |
281 | } | |
282 | ||
283 | /* | |
284 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 285 | * tracepoint mutex held. |
f99be407 | 286 | */ |
34f7f142 | 287 | static struct tracepoint_entry *add_tracepoint(const char *provider_name, const char *event_name, |
67e5f391 | 288 | const char *signature) |
f99be407 | 289 | { |
10c56168 DG |
290 | struct cds_hlist_head *head; |
291 | struct cds_hlist_node *node; | |
f99be407 | 292 | struct tracepoint_entry *e; |
2c05c691 | 293 | size_t sig_len = strlen(signature); |
34f7f142 MD |
294 | size_t sig_off, provider_name_off, event_name_off; |
295 | size_t provider_name_len = strlen(provider_name); | |
296 | size_t event_name_len = strlen(event_name); | |
ff412fb5 | 297 | uint32_t hash; |
f99be407 | 298 | |
34f7f142 MD |
299 | hash = jhash(provider_name, provider_name_len, 0) ^ |
300 | jhash(event_name, event_name_len, 0); | |
f99be407 | 301 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 302 | cds_hlist_for_each_entry(e, node, head, hlist) { |
34f7f142 MD |
303 | if (!strcmp(event_name, e->event_name) && !strcmp(provider_name, e->provider_name)) { |
304 | DBG("tracepoint \"%s:%s\" busy", provider_name, event_name); | |
f99be407 PMF |
305 | return ERR_PTR(-EEXIST); /* Already there */ |
306 | } | |
307 | } | |
2c05c691 | 308 | |
f99be407 | 309 | /* |
2c05c691 FD |
310 | * Using zmalloc here to allocate a variable length elements: name and |
311 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 312 | */ |
34f7f142 MD |
313 | provider_name_off = sizeof(struct tracepoint_entry); |
314 | event_name_off = provider_name_off + provider_name_len + 1; | |
315 | sig_off = event_name_off + event_name_len + 1; | |
2c05c691 | 316 | |
34f7f142 MD |
317 | e = zmalloc(sizeof(struct tracepoint_entry) + provider_name_len + 1 + |
318 | event_name_len + 1 + sig_len + 1); | |
f99be407 PMF |
319 | if (!e) |
320 | return ERR_PTR(-ENOMEM); | |
34f7f142 MD |
321 | e->provider_name = (char *) e + provider_name_off; |
322 | memcpy(e->provider_name, provider_name, provider_name_len + 1); | |
323 | e->provider_name[provider_name_len] = '\0'; | |
324 | ||
325 | e->event_name = (char *) e + event_name_off; | |
326 | memcpy(e->event_name, event_name, event_name_len + 1); | |
327 | e->event_name[event_name_len] = '\0'; | |
2c05c691 FD |
328 | |
329 | e->signature = (char *) e + sig_off; | |
330 | memcpy(e->signature, signature, sig_len + 1); | |
331 | e->signature[sig_len] = '\0'; | |
332 | ||
9dec086e | 333 | e->probes = NULL; |
f99be407 | 334 | e->refcount = 0; |
8a7ad54b | 335 | e->callsite_refcount = 0; |
2c05c691 | 336 | |
10c56168 | 337 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
338 | return e; |
339 | } | |
340 | ||
341 | /* | |
342 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 343 | * tracepoint mutex held. |
f99be407 | 344 | */ |
efa2c591 | 345 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 346 | { |
10c56168 | 347 | cds_hlist_del(&e->hlist); |
909bc43f | 348 | free(e); |
f99be407 PMF |
349 | } |
350 | ||
351 | /* | |
352 | * Sets the probe callback corresponding to one tracepoint. | |
353 | */ | |
354 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 355 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 356 | { |
34f7f142 MD |
357 | WARN_ON(strcmp((*entry)->provider_name, elem->provider_name) != 0); |
358 | WARN_ON(strcmp((*entry)->event_name, elem->event_name) != 0); | |
67e5f391 MD |
359 | /* |
360 | * Check that signatures match before connecting a probe to a | |
361 | * tracepoint. Warn the user if they don't. | |
362 | */ | |
363 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
364 | static int warned = 0; | |
365 | ||
366 | /* Only print once, don't flood console. */ | |
367 | if (!warned) { | |
368 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
34f7f142 MD |
369 | WARN("Tracepoint \"%s:%s\" signatures: call: \"%s\" vs probe: \"%s\".", |
370 | elem->provider_name, elem->event_name, elem->signature, (*entry)->signature); | |
67e5f391 MD |
371 | warned = 1; |
372 | } | |
373 | /* Don't accept connecting non-matching signatures. */ | |
374 | return; | |
375 | } | |
f99be407 PMF |
376 | |
377 | /* | |
0222e121 | 378 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
379 | * probe callbacks array is consistent before setting a pointer to it. |
380 | * This array is referenced by __DO_TRACE from | |
0222e121 | 381 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
382 | * is used. |
383 | */ | |
10544ee8 | 384 | lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 385 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
386 | } |
387 | ||
388 | /* | |
389 | * Disable a tracepoint and its probe callback. | |
390 | * Note: only waiting an RCU period after setting elem->call to the empty | |
391 | * function insures that the original callback is not used anymore. This insured | |
392 | * by preempt_disable around the call site. | |
393 | */ | |
1a206094 | 394 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 395 | { |
c082d14b | 396 | CMM_STORE_SHARED(elem->state, 0); |
10544ee8 | 397 | lttng_ust_rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
398 | } |
399 | ||
33f8ed87 MD |
400 | /* |
401 | * Add the callsite to the callsite hash table. Must be called with | |
402 | * tracepoint mutex held. | |
403 | */ | |
1a206094 | 404 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
405 | { |
406 | struct cds_hlist_head *head; | |
407 | struct callsite_entry *e; | |
33f8ed87 | 408 | uint32_t hash; |
8a7ad54b | 409 | struct tracepoint_entry *tp_entry; |
33f8ed87 | 410 | |
34f7f142 MD |
411 | if (!lttng_ust_tp_validate_event_name(tp)) { |
412 | WARN("Rejecting tracepoint name \"%s:%s\" which exceeds size limits of %u chars", | |
413 | tp->provider_name, tp->event_name, LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1); | |
414 | return; | |
33f8ed87 | 415 | } |
34f7f142 MD |
416 | hash = jhash(tp->provider_name, strlen(tp->provider_name), 0) ^ |
417 | jhash(tp->event_name, strlen(tp->event_name), 0); | |
33f8ed87 MD |
418 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; |
419 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 | 420 | if (!e) { |
34f7f142 | 421 | PERROR("Unable to add callsite for tracepoint \"%s:%s\"", tp->provider_name, tp->event_name); |
d6297168 MD |
422 | return; |
423 | } | |
33f8ed87 MD |
424 | cds_hlist_add_head(&e->hlist, head); |
425 | e->tp = tp; | |
426 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b | 427 | |
34f7f142 | 428 | tp_entry = get_tracepoint(tp->provider_name, tp->event_name); |
8a7ad54b IJ |
429 | if (!tp_entry) |
430 | return; | |
431 | tp_entry->callsite_refcount++; | |
2c05c691 | 432 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
433 | } |
434 | ||
435 | /* | |
436 | * Remove the callsite from the callsite hash table and from lib | |
437 | * callsite list. Must be called with tracepoint mutex held. | |
438 | */ | |
439 | static void remove_callsite(struct callsite_entry *e) | |
440 | { | |
8a7ad54b IJ |
441 | struct tracepoint_entry *tp_entry; |
442 | ||
34f7f142 | 443 | tp_entry = get_tracepoint(e->tp->provider_name, e->tp->event_name); |
8a7ad54b | 444 | if (tp_entry) { |
2c05c691 FD |
445 | if (e->tp_entry_callsite_ref) |
446 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
447 | if (tp_entry->callsite_refcount == 0) |
448 | disable_tracepoint(e->tp); | |
449 | } | |
33f8ed87 MD |
450 | cds_hlist_del(&e->hlist); |
451 | cds_list_del(&e->node); | |
452 | free(e); | |
453 | } | |
454 | ||
3469bbbe MD |
455 | /* |
456 | * Enable/disable all callsites based on the state of a specific | |
457 | * tracepoint entry. | |
458 | * Must be called with tracepoint mutex held. | |
459 | */ | |
34f7f142 | 460 | static void tracepoint_sync_callsites(const char *provider_name, const char *event_name) |
3469bbbe | 461 | { |
34f7f142 | 462 | struct tracepoint_entry *tp_entry; |
3469bbbe MD |
463 | struct cds_hlist_head *head; |
464 | struct cds_hlist_node *node; | |
465 | struct callsite_entry *e; | |
3469bbbe | 466 | uint32_t hash; |
3469bbbe | 467 | |
34f7f142 MD |
468 | tp_entry = get_tracepoint(provider_name, event_name); |
469 | hash = jhash(provider_name, strlen(provider_name), 0) ^ | |
470 | jhash(event_name, strlen(event_name), 0); | |
3469bbbe MD |
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 | 474 | |
34f7f142 MD |
475 | if (strcmp(event_name, tp->event_name)) |
476 | continue; | |
477 | if (strcmp(provider_name, tp->provider_name)) | |
3469bbbe MD |
478 | continue; |
479 | if (tp_entry) { | |
2c05c691 FD |
480 | if (!e->tp_entry_callsite_ref) { |
481 | tp_entry->callsite_refcount++; | |
482 | e->tp_entry_callsite_ref = true; | |
483 | } | |
3469bbbe MD |
484 | set_tracepoint(&tp_entry, tp, |
485 | !!tp_entry->refcount); | |
486 | } else { | |
487 | disable_tracepoint(tp); | |
2c05c691 | 488 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
489 | } |
490 | } | |
491 | } | |
492 | ||
f99be407 PMF |
493 | /** |
494 | * tracepoint_update_probe_range - Update a probe range | |
495 | * @begin: beginning of the range | |
496 | * @end: end of the range | |
497 | * | |
498 | * Updates the probe callback corresponding to a range of tracepoints. | |
499 | */ | |
b27f8e75 | 500 | static |
1a206094 SM |
501 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
502 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 503 | { |
1a206094 | 504 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
505 | struct tracepoint_entry *mark_entry; |
506 | ||
f99be407 | 507 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
508 | if (!*iter) |
509 | continue; /* skip dummy */ | |
34f7f142 MD |
510 | if (!(*iter)->provider_name || !(*iter)->event_name) { |
511 | disable_tracepoint(*iter); | |
512 | continue; | |
513 | } | |
514 | if (!lttng_ust_tp_validate_event_name(*iter)) { | |
515 | WARN("Rejecting tracepoint name \"%s:%s\" which exceeds size limits of %u chars", | |
516 | (*iter)->provider_name, (*iter)->event_name, LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1); | |
f218ff28 | 517 | disable_tracepoint(*iter); |
9dec086e NC |
518 | continue; |
519 | } | |
34f7f142 | 520 | mark_entry = get_tracepoint((*iter)->provider_name, (*iter)->event_name); |
f99be407 | 521 | if (mark_entry) { |
f218ff28 | 522 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
523 | !!mark_entry->refcount); |
524 | } else { | |
f218ff28 | 525 | disable_tracepoint(*iter); |
f99be407 PMF |
526 | } |
527 | } | |
f99be407 PMF |
528 | } |
529 | ||
5da10905 | 530 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 531 | { |
5da10905 MD |
532 | tracepoint_update_probe_range(lib->tracepoints_start, |
533 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
534 | } |
535 | ||
3469bbbe MD |
536 | static void lib_register_callsites(struct tracepoint_lib *lib) |
537 | { | |
1a206094 SM |
538 | struct lttng_ust_tracepoint * const *begin; |
539 | struct lttng_ust_tracepoint * const *end; | |
540 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
541 | |
542 | begin = lib->tracepoints_start; | |
543 | end = lib->tracepoints_start + lib->tracepoints_count; | |
544 | ||
545 | for (iter = begin; iter < end; iter++) { | |
546 | if (!*iter) | |
547 | continue; /* skip dummy */ | |
34f7f142 | 548 | if (!(*iter)->provider_name || !(*iter)->event_name) { |
3469bbbe MD |
549 | continue; |
550 | } | |
60d87029 | 551 | add_callsite(lib, *iter); |
3469bbbe MD |
552 | } |
553 | } | |
554 | ||
555 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
556 | { | |
557 | struct callsite_entry *callsite, *tmp; | |
558 | ||
559 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
560 | remove_callsite(callsite); | |
561 | } | |
562 | ||
f99be407 PMF |
563 | /* |
564 | * Update probes, removing the faulty probes. | |
565 | */ | |
566 | static void tracepoint_update_probes(void) | |
567 | { | |
5da10905 MD |
568 | struct tracepoint_lib *lib; |
569 | ||
b27f8e75 | 570 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
571 | cds_list_for_each_entry(lib, &libs, list) |
572 | lib_update_tracepoints(lib); | |
f99be407 PMF |
573 | } |
574 | ||
1a206094 | 575 | static struct lttng_ust_tracepoint_probe * |
34f7f142 MD |
576 | tracepoint_add_probe(const char *provider_name, const char *event_name, |
577 | void (*probe)(void), void *data, const char *signature) | |
f99be407 PMF |
578 | { |
579 | struct tracepoint_entry *entry; | |
1a206094 | 580 | struct lttng_ust_tracepoint_probe *old; |
f99be407 | 581 | |
34f7f142 | 582 | entry = get_tracepoint(provider_name, event_name); |
2c05c691 FD |
583 | if (entry) { |
584 | if (strcmp(entry->signature, signature) != 0) { | |
34f7f142 MD |
585 | ERR("Tracepoint \"%s:%s\": tracepoint and probe signature do not match: \"%s\" vs \"%s\".", |
586 | provider_name, event_name, entry->signature, signature); | |
2c05c691 FD |
587 | return ERR_PTR(-EINVAL); |
588 | } | |
589 | } else { | |
34f7f142 | 590 | entry = add_tracepoint(provider_name, event_name, signature); |
f99be407 | 591 | if (IS_ERR(entry)) |
1a206094 | 592 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 593 | } |
9dec086e | 594 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
595 | if (IS_ERR(old) && !entry->refcount) |
596 | remove_tracepoint(entry); | |
597 | return old; | |
598 | } | |
599 | ||
baa1e0bc MD |
600 | static void tracepoint_release_queue_add_old_probes(void *old) |
601 | { | |
602 | release_queue_need_update = 1; | |
603 | if (old) { | |
604 | struct tp_probes *tp_probes = caa_container_of(old, | |
605 | struct tp_probes, probes[0]); | |
606 | cds_list_add(&tp_probes->u.list, &release_queue); | |
607 | } | |
608 | } | |
609 | ||
f99be407 | 610 | /** |
0274f7f2 | 611 | * lttng_ust_tracepoint_probe_register - Connect a probe to a tracepoint |
34f7f142 MD |
612 | * @name: tracepoint provider name |
613 | * @name: tracepoint event name | |
f99be407 PMF |
614 | * @probe: probe handler |
615 | * | |
616 | * Returns 0 if ok, error value on error. | |
617 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 618 | * Called with the tracepoint mutex held. |
f99be407 | 619 | */ |
0274f7f2 | 620 | int lttng_ust_tracepoint_probe_register(const char *provider_name, const char *event_name, |
34f7f142 | 621 | void (*probe)(void), void *data, const char *signature) |
f99be407 PMF |
622 | { |
623 | void *old; | |
8792fbae | 624 | int ret = 0; |
f99be407 | 625 | |
34f7f142 | 626 | DBG("Registering probe to tracepoint \"%s:%s\"", provider_name, event_name); |
05780d81 | 627 | |
8792fbae | 628 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 629 | old = tracepoint_add_probe(provider_name, event_name, probe, data, signature); |
8792fbae MD |
630 | if (IS_ERR(old)) { |
631 | ret = PTR_ERR(old); | |
632 | goto end; | |
633 | } | |
f99be407 | 634 | |
34f7f142 | 635 | tracepoint_sync_callsites(provider_name, event_name); |
f99be407 | 636 | release_probes(old); |
8792fbae MD |
637 | end: |
638 | pthread_mutex_unlock(&tracepoint_mutex); | |
639 | return ret; | |
f99be407 | 640 | } |
f99be407 | 641 | |
baa1e0bc | 642 | /* |
0274f7f2 | 643 | * Caller needs to invoke lttng_ust_tracepoint_probe_release_queue() after |
d10a2205 | 644 | * calling lttng_ust_tp_probe_register_queue_release() one or multiple |
baa1e0bc MD |
645 | * times to ensure it does not leak memory. |
646 | */ | |
34f7f142 | 647 | int lttng_ust_tp_probe_register_queue_release(const char *provider_name, const char *event_name, |
baa1e0bc MD |
648 | void (*probe)(void), void *data, const char *signature) |
649 | { | |
650 | void *old; | |
651 | int ret = 0; | |
652 | ||
34f7f142 | 653 | DBG("Registering probe to tracepoint \"%s:%s\". Queuing release.", provider_name, event_name); |
baa1e0bc MD |
654 | |
655 | pthread_mutex_lock(&tracepoint_mutex); | |
34f7f142 | 656 | old = tracepoint_add_probe(provider_name, event_name, probe, data, signature); |
baa1e0bc MD |
657 | if (IS_ERR(old)) { |
658 | ret = PTR_ERR(old); | |
659 | goto end; | |
660 | } | |
661 | ||
34f7f142 | 662 | tracepoint_sync_callsites(provider_name, event_name); |
baa1e0bc MD |
663 | tracepoint_release_queue_add_old_probes(old); |
664 | end: | |
665 | pthread_mutex_unlock(&tracepoint_mutex); | |
666 | return ret; | |
667 | } | |
668 | ||
34f7f142 MD |
669 | static void *tracepoint_remove_probe(const char *provider_name, const char *event_name, |
670 | void (*probe)(void), void *data) | |
f99be407 PMF |
671 | { |
672 | struct tracepoint_entry *entry; | |
673 | void *old; | |
674 | ||
34f7f142 | 675 | entry = get_tracepoint(provider_name, event_name); |
f99be407 PMF |
676 | if (!entry) |
677 | return ERR_PTR(-ENOENT); | |
9dec086e | 678 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
679 | if (IS_ERR(old)) |
680 | return old; | |
681 | if (!entry->refcount) | |
682 | remove_tracepoint(entry); | |
683 | return old; | |
684 | } | |
685 | ||
686 | /** | |
687 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
34f7f142 MD |
688 | * @provider_name: tracepoint provider name |
689 | * @event_name: tracepoint event name | |
f99be407 | 690 | * @probe: probe function pointer |
9dec086e | 691 | * @probe: probe data pointer |
f99be407 | 692 | */ |
0274f7f2 | 693 | int lttng_ust_tracepoint_probe_unregister(const char *provider_name, const char *event_name, |
34f7f142 | 694 | void (*probe)(void), void *data) |
f99be407 PMF |
695 | { |
696 | void *old; | |
8792fbae | 697 | int ret = 0; |
f99be407 | 698 | |
34f7f142 | 699 | DBG("Un-registering probe \"%s:%s\" from tracepoint %p", provider_name, event_name, probe); |
05780d81 | 700 | |
8792fbae | 701 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 702 | old = tracepoint_remove_probe(provider_name, event_name, probe, data); |
8792fbae MD |
703 | if (IS_ERR(old)) { |
704 | ret = PTR_ERR(old); | |
705 | goto end; | |
706 | } | |
34f7f142 | 707 | tracepoint_sync_callsites(provider_name, event_name); |
f99be407 | 708 | release_probes(old); |
8792fbae MD |
709 | end: |
710 | pthread_mutex_unlock(&tracepoint_mutex); | |
711 | return ret; | |
f99be407 | 712 | } |
f99be407 | 713 | |
baa1e0bc | 714 | /* |
0274f7f2 | 715 | * Caller needs to invoke lttng_ust_tracepoint_probe_release_queue() after |
d10a2205 | 716 | * calling lttng_ust_tp_probe_unregister_queue_release() one or multiple |
baa1e0bc MD |
717 | * times to ensure it does not leak memory. |
718 | */ | |
34f7f142 | 719 | int lttng_ust_tp_probe_unregister_queue_release(const char *provider_name, const char *event_name, |
baa1e0bc MD |
720 | void (*probe)(void), void *data) |
721 | { | |
722 | void *old; | |
723 | int ret = 0; | |
724 | ||
34f7f142 | 725 | DBG("Un-registering probe from tracepoint \"%s:%s\". Queuing release.", provider_name, event_name); |
baa1e0bc MD |
726 | |
727 | pthread_mutex_lock(&tracepoint_mutex); | |
34f7f142 | 728 | old = tracepoint_remove_probe(provider_name, event_name, probe, data); |
baa1e0bc MD |
729 | if (IS_ERR(old)) { |
730 | ret = PTR_ERR(old); | |
731 | goto end; | |
732 | } | |
34f7f142 | 733 | tracepoint_sync_callsites(provider_name, event_name); |
baa1e0bc MD |
734 | tracepoint_release_queue_add_old_probes(old); |
735 | end: | |
736 | pthread_mutex_unlock(&tracepoint_mutex); | |
737 | return ret; | |
738 | } | |
739 | ||
d10a2205 | 740 | void lttng_ust_tp_probe_prune_release_queue(void) |
baa1e0bc MD |
741 | { |
742 | CDS_LIST_HEAD(release_probes); | |
743 | struct tp_probes *pos, *next; | |
744 | ||
745 | DBG("Release queue of unregistered tracepoint probes."); | |
746 | ||
747 | pthread_mutex_lock(&tracepoint_mutex); | |
748 | if (!release_queue_need_update) | |
749 | goto end; | |
750 | if (!cds_list_empty(&release_queue)) | |
751 | cds_list_replace_init(&release_queue, &release_probes); | |
752 | release_queue_need_update = 0; | |
753 | ||
754 | /* Wait for grace period between all sync_callsites and free. */ | |
b653ddc1 | 755 | lttng_ust_urcu_synchronize_rcu(); |
baa1e0bc MD |
756 | |
757 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
758 | cds_list_del(&pos->u.list); | |
759 | free(pos); | |
760 | } | |
761 | end: | |
762 | pthread_mutex_unlock(&tracepoint_mutex); | |
763 | } | |
764 | ||
f99be407 PMF |
765 | static void tracepoint_add_old_probes(void *old) |
766 | { | |
767 | need_update = 1; | |
768 | if (old) { | |
b728d87e | 769 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 770 | struct tp_probes, probes[0]); |
0222e121 | 771 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
772 | } |
773 | } | |
774 | ||
775 | /** | |
776 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
777 | * @name: tracepoint name | |
778 | * @probe: probe handler | |
779 | * | |
780 | * caller must call tracepoint_probe_update_all() | |
781 | */ | |
34f7f142 MD |
782 | int tracepoint_probe_register_noupdate(const char *provider_name, const char *event_name, |
783 | void (*probe)(void), void *data, const char *signature) | |
f99be407 PMF |
784 | { |
785 | void *old; | |
8792fbae | 786 | int ret = 0; |
f99be407 | 787 | |
8792fbae | 788 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 789 | old = tracepoint_add_probe(provider_name, event_name, probe, data, signature); |
f99be407 | 790 | if (IS_ERR(old)) { |
8792fbae MD |
791 | ret = PTR_ERR(old); |
792 | goto end; | |
f99be407 PMF |
793 | } |
794 | tracepoint_add_old_probes(old); | |
8792fbae MD |
795 | end: |
796 | pthread_mutex_unlock(&tracepoint_mutex); | |
797 | return ret; | |
f99be407 | 798 | } |
f99be407 PMF |
799 | |
800 | /** | |
801 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
802 | * @name: tracepoint name | |
803 | * @probe: probe function pointer | |
804 | * | |
805 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 806 | * Called with the tracepoint mutex held. |
f99be407 | 807 | */ |
34f7f142 MD |
808 | int tracepoint_probe_unregister_noupdate(const char *provider_name, const char *event_name, |
809 | void (*probe)(void), void *data) | |
f99be407 PMF |
810 | { |
811 | void *old; | |
8792fbae | 812 | int ret = 0; |
f99be407 | 813 | |
34f7f142 | 814 | DBG("Un-registering probe from tracepoint \"%s:%s\"", provider_name, event_name); |
05780d81 | 815 | |
8792fbae | 816 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 817 | old = tracepoint_remove_probe(provider_name, event_name, probe, data); |
f99be407 | 818 | if (IS_ERR(old)) { |
8792fbae MD |
819 | ret = PTR_ERR(old); |
820 | goto end; | |
f99be407 PMF |
821 | } |
822 | tracepoint_add_old_probes(old); | |
8792fbae MD |
823 | end: |
824 | pthread_mutex_unlock(&tracepoint_mutex); | |
825 | return ret; | |
f99be407 | 826 | } |
f99be407 PMF |
827 | |
828 | /** | |
829 | * tracepoint_probe_update_all - update tracepoints | |
830 | */ | |
831 | void tracepoint_probe_update_all(void) | |
832 | { | |
0222e121 | 833 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
834 | struct tp_probes *pos, *next; |
835 | ||
8792fbae | 836 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 837 | if (!need_update) { |
8792fbae | 838 | goto end; |
f99be407 | 839 | } |
0222e121 MD |
840 | if (!cds_list_empty(&old_probes)) |
841 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 842 | need_update = 0; |
f99be407 PMF |
843 | |
844 | tracepoint_update_probes(); | |
baa1e0bc | 845 | /* Wait for grace period between update_probes and free. */ |
b653ddc1 | 846 | lttng_ust_urcu_synchronize_rcu(); |
0222e121 MD |
847 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
848 | cds_list_del(&pos->u.list); | |
909bc43f | 849 | free(pos); |
f99be407 | 850 | } |
8792fbae MD |
851 | end: |
852 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 853 | } |
f99be407 | 854 | |
1a206094 SM |
855 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
856 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 857 | { |
f218ff28 | 858 | if (new_tracepoint_cb) { |
1a206094 | 859 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 860 | |
b27f8e75 | 861 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
862 | if (*t) |
863 | new_tracepoint_cb(*t); | |
474d745f PMF |
864 | } |
865 | } | |
f99be407 | 866 | } |
f99be407 | 867 | |
10544ee8 MD |
868 | /* |
869 | * tracepoint_{un,}register_lib is meant to be looked up by instrumented | |
870 | * applications through dlsym(). If found, those can register their | |
871 | * tracepoints, else those tracepoints will not be available for | |
872 | * tracing. The number at the end of those symbols acts as a major | |
873 | * version for tracepoints. | |
874 | * | |
875 | * Older instrumented applications should still work with newer | |
876 | * liblttng-ust, but it is fine that instrumented applications compiled | |
877 | * against recent liblttng-ust headers require a recent liblttng-ust | |
878 | * runtime for those tracepoints to be taken into account. | |
879 | */ | |
4b4a1337 MJ |
880 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
881 | int tracepoints_count); | |
ae14f822 | 882 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
10544ee8 | 883 | int tracepoints_count) |
474d745f | 884 | { |
b467f7a7 | 885 | struct tracepoint_lib *pl, *iter; |
474d745f | 886 | |
25afb7ac | 887 | lttng_ust_tp_init(); |
edaa1431 | 888 | |
1dba3e6c | 889 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
890 | if (!pl) { |
891 | PERROR("Unable to register tracepoint lib"); | |
892 | return -1; | |
893 | } | |
474d745f PMF |
894 | pl->tracepoints_start = tracepoints_start; |
895 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 896 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 897 | |
8792fbae | 898 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
899 | /* |
900 | * We sort the libs by struct lib pointer address. | |
901 | */ | |
902 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
903 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
904 | if (iter < pl) { | |
905 | /* We belong to the location right after iter. */ | |
906 | cds_list_add(&pl->list, &iter->list); | |
907 | goto lib_added; | |
908 | } | |
909 | } | |
910 | /* We should be added at the head of the list */ | |
0222e121 | 911 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 912 | lib_added: |
474d745f | 913 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 914 | lib_register_callsites(pl); |
5da10905 | 915 | lib_update_tracepoints(pl); |
8792fbae | 916 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 917 | |
1fcf7ad7 MD |
918 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
919 | tracepoints_start, tracepoints_count); | |
c6e6343c | 920 | if (lttng_ust_logging_debug_enabled()) { |
05780d81 MD |
921 | int i; |
922 | ||
923 | for (i = 0; i < tracepoints_count; i++) { | |
34f7f142 MD |
924 | if (!lttng_ust_tp_validate_event_name(tracepoints_start[i])) |
925 | continue; | |
926 | DBG("registered tracepoint: \"%s:%s\"", | |
927 | tracepoints_start[i]->provider_name, | |
928 | tracepoints_start[i]->event_name); | |
05780d81 MD |
929 | } |
930 | } | |
9dec086e | 931 | |
474d745f PMF |
932 | return 0; |
933 | } | |
934 | ||
4b4a1337 | 935 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start); |
ae14f822 | 936 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) |
474d745f | 937 | { |
24b6668c PMF |
938 | struct tracepoint_lib *lib; |
939 | ||
8792fbae | 940 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 941 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
942 | if (lib->tracepoints_start != tracepoints_start) |
943 | continue; | |
1622ba22 | 944 | |
3469bbbe MD |
945 | cds_list_del(&lib->list); |
946 | /* | |
8a7ad54b IJ |
947 | * Unregistering a callsite also decreases the |
948 | * callsite reference count of the corresponding | |
949 | * tracepoint, and disables the tracepoint if | |
950 | * the reference count drops to zero. | |
3469bbbe | 951 | */ |
3469bbbe MD |
952 | lib_unregister_callsites(lib); |
953 | DBG("just unregistered a tracepoints section from %p", | |
954 | lib->tracepoints_start); | |
955 | free(lib); | |
956 | break; | |
24b6668c | 957 | } |
8792fbae | 958 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
959 | return 0; |
960 | } | |
b27f8e75 | 961 | |
5517d34d MD |
962 | /* |
963 | * Report in debug message whether the compiler correctly supports weak | |
964 | * hidden symbols. This test checks that the address associated with two | |
965 | * weak symbols with hidden visibility is the same when declared within | |
966 | * two compile units part of the same module. | |
967 | */ | |
968 | static void check_weak_hidden(void) | |
969 | { | |
b0e63efd | 970 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
0274f7f2 | 971 | <tng_ust_tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? |
b0e63efd MD |
972 | "SAME address" : |
973 | "DIFFERENT addresses"); | |
974 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
0274f7f2 | 975 | <tng_ust_tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? |
b0e63efd MD |
976 | "SAME address" : |
977 | "DIFFERENT addresses"); | |
978 | DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.", | |
0274f7f2 | 979 | <tng_ust_tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? |
b0e63efd MD |
980 | "SAME address" : |
981 | "DIFFERENT addresses"); | |
5517d34d MD |
982 | } |
983 | ||
25afb7ac | 984 | void lttng_ust_tp_init(void) |
b27f8e75 | 985 | { |
edaa1431 MD |
986 | if (uatomic_xchg(&initialized, 1) == 1) |
987 | return; | |
c6e6343c | 988 | lttng_ust_logging_init(); |
fca97dfd | 989 | lttng_ust_common_ctor(); |
5517d34d | 990 | check_weak_hidden(); |
b27f8e75 MD |
991 | } |
992 | ||
25afb7ac | 993 | void lttng_ust_tp_exit(void) |
b27f8e75 | 994 | { |
17dfb34b | 995 | initialized = 0; |
b27f8e75 | 996 | } |
40b2b5a4 MD |
997 | |
998 | /* | |
999 | * Create the wrapper symbols. | |
1000 | */ | |
10544ee8 MD |
1001 | #undef tp_rcu_read_lock |
1002 | #undef tp_rcu_read_unlock | |
1003 | #undef tp_rcu_dereference | |
40b2b5a4 | 1004 | |
4b4a1337 | 1005 | void tp_rcu_read_lock(void); |
10544ee8 | 1006 | void tp_rcu_read_lock(void) |
40b2b5a4 | 1007 | { |
10544ee8 | 1008 | lttng_ust_urcu_read_lock(); |
40b2b5a4 MD |
1009 | } |
1010 | ||
4b4a1337 | 1011 | void tp_rcu_read_unlock(void); |
10544ee8 | 1012 | void tp_rcu_read_unlock(void) |
40b2b5a4 | 1013 | { |
10544ee8 | 1014 | lttng_ust_urcu_read_unlock(); |
40b2b5a4 MD |
1015 | } |
1016 | ||
4b4a1337 | 1017 | void *tp_rcu_dereference_sym(void *p); |
10544ee8 | 1018 | void *tp_rcu_dereference_sym(void *p) |
40b2b5a4 | 1019 | { |
10544ee8 | 1020 | return lttng_ust_rcu_dereference(p); |
40b2b5a4 | 1021 | } |
0fd0de10 FD |
1022 | |
1023 | /* | |
1024 | * Programs that have threads that survive after they exit, and therefore call | |
1025 | * library destructors, should disable the tracepoint destructors by calling | |
1026 | * tp_disable_destructors(). This will leak the tracepoint | |
1027 | * instrumentation library shared object, leaving its teardown to the operating | |
1028 | * system process teardown. | |
1029 | * | |
1030 | * To access and/or modify this value, users need to use a combination of | |
1031 | * dlopen(3) and dlsym(3) to get an handle on the | |
1032 | * tp_disable_destructors and tp_get_destructors_state symbols below. | |
1033 | */ | |
4b4a1337 | 1034 | void tp_disable_destructors(void); |
0fd0de10 FD |
1035 | void tp_disable_destructors(void) |
1036 | { | |
1037 | uatomic_set(&tracepoint_destructors_state, 0); | |
1038 | } | |
1039 | ||
1040 | /* | |
1041 | * Returns 1 if the destructors are enabled and should be executed. | |
1042 | * Returns 0 if the destructors are disabled. | |
1043 | */ | |
4b4a1337 | 1044 | int tp_get_destructors_state(void); |
0fd0de10 FD |
1045 | int tp_get_destructors_state(void) |
1046 | { | |
1047 | return uatomic_read(&tracepoint_destructors_state); | |
1048 | } |