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> |
67418c35 | 15 | #include <dlfcn.h> |
44c72f10 | 16 | |
b728d87e | 17 | #include <urcu/arch.h> |
10544ee8 | 18 | #include <lttng/urcu/urcu-ust.h> |
10c56168 | 19 | #include <urcu/hlist.h> |
edaa1431 | 20 | #include <urcu/uatomic.h> |
b728d87e | 21 | #include <urcu/compiler.h> |
c082d14b | 22 | #include <urcu/system.h> |
44c72f10 MD |
23 | |
24 | #include <lttng/tracepoint.h> | |
fd17d7ce | 25 | #include <lttng/ust-abi.h> /* for LTTNG_UST_ABI_SYM_NAME_LEN */ |
fca97dfd | 26 | #include <lttng/ust-common.h> |
44c72f10 | 27 | |
9d315d6d MJ |
28 | #include "common/logging.h" |
29 | #include "common/macros.h" | |
474d745f | 30 | |
8f51c684 MJ |
31 | #include "lib/lttng-ust-tracepoint/tracepoint.h" |
32 | #include "common/tracepoint.h" | |
e58e5ad5 | 33 | #include "common/jhash.h" |
9c4fe08d | 34 | #include "common/err-ptr.h" |
b0c4126f | 35 | |
5517d34d | 36 | /* Test compiler support for weak symbols with hidden visibility. */ |
0274f7f2 MJ |
37 | int lttng_ust_tracepoint_test_symbol1 __attribute__((weak, visibility("hidden"))); |
38 | void *lttng_ust_tracepoint_test_symbol2 __attribute__((weak, visibility("hidden"))); | |
b0e63efd MD |
39 | struct { |
40 | char a[24]; | |
0274f7f2 | 41 | } lttng_ust_tracepoint_test_symbol3 __attribute__((weak, visibility("hidden"))); |
5517d34d | 42 | |
f99be407 PMF |
43 | /* Set to 1 to enable tracepoint debug output */ |
44 | static const int tracepoint_debug; | |
b27f8e75 | 45 | static int initialized; |
0fd0de10 FD |
46 | |
47 | /* | |
48 | * If tracepoint_destructors_state = 1, tracepoint destructors are | |
49 | * enabled. They are disabled otherwise. | |
50 | */ | |
51 | static int tracepoint_destructors_state = 1; | |
52 | ||
1a206094 | 53 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 54 | |
8792fbae MD |
55 | /* |
56 | * tracepoint_mutex nests inside UST mutex. | |
57 | * | |
58 | * Note about interaction with fork/clone: UST does not hold the | |
59 | * tracepoint mutex across fork/clone because it is either: | |
60 | * - nested within UST mutex, in which case holding the UST mutex across | |
61 | * fork/clone suffice, | |
62 | * - taken by a library constructor, which should never race with a | |
63 | * fork/clone if the application is expected to continue running with | |
64 | * the same memory layout (no following exec()). | |
65 | */ | |
66 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
67 | ||
efa2c591 MD |
68 | /* |
69 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 70 | * Protected by tracepoint mutex. |
efa2c591 | 71 | */ |
0222e121 | 72 | static CDS_LIST_HEAD(libs); |
474d745f | 73 | |
f99be407 | 74 | /* |
8792fbae | 75 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 76 | * the library list. |
8792fbae | 77 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
14227bde MJ |
78 | * excepts calls to lttng_ust_tracepoint_module_register and |
79 | * lttng_ust_tracepoint_module_unregister, which take the tracepoint mutex themselves. | |
f99be407 | 80 | */ |
f99be407 PMF |
81 | |
82 | /* | |
83 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 84 | * Protected by tracepoint mutex. |
f99be407 | 85 | */ |
814f7df1 | 86 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 87 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 88 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 89 | |
b27f8e75 MD |
90 | static CDS_LIST_HEAD(old_probes); |
91 | static int need_update; | |
92 | ||
baa1e0bc MD |
93 | static CDS_LIST_HEAD(release_queue); |
94 | static int release_queue_need_update; | |
95 | ||
f99be407 PMF |
96 | /* |
97 | * Note about RCU : | |
98 | * It is used to to delay the free of multiple probes array until a quiescent | |
99 | * state is reached. | |
8792fbae | 100 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
101 | */ |
102 | struct tracepoint_entry { | |
10c56168 | 103 | struct cds_hlist_node hlist; |
1a206094 | 104 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 105 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 106 | int callsite_refcount; /* how many libs use this tracepoint */ |
2c05c691 | 107 | char *signature; |
34f7f142 MD |
108 | char *provider_name; |
109 | char *event_name; | |
f99be407 PMF |
110 | }; |
111 | ||
112 | struct tp_probes { | |
113 | union { | |
0222e121 | 114 | struct cds_list_head list; |
ade7037b MD |
115 | /* Field below only used for call_rcu scheme */ |
116 | /* struct rcu_head head; */ | |
f99be407 | 117 | } u; |
1a206094 | 118 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
119 | }; |
120 | ||
3469bbbe MD |
121 | /* |
122 | * Callsite hash table, containing the tracepoint call sites. | |
123 | * Protected by tracepoint mutex. | |
124 | */ | |
125 | #define CALLSITE_HASH_BITS 12 | |
126 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
127 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
128 | ||
129 | struct callsite_entry { | |
130 | struct cds_hlist_node hlist; /* hash table node */ | |
131 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 132 | struct lttng_ust_tracepoint *tp; |
2c05c691 | 133 | bool tp_entry_callsite_ref; /* Has a tp_entry took a ref on this callsite */ |
3469bbbe MD |
134 | }; |
135 | ||
81b16412 MD |
136 | lttng_ust_static_assert(LTTNG_UST_TRACEPOINT_NAME_LEN_MAX == LTTNG_UST_ABI_SYM_NAME_LEN, |
137 | "Tracepoint name max length mismatch between UST ABI and tracepoint API", | |
138 | Tracepoint_name_max_length_mismatch); | |
139 | ||
34f7f142 MD |
140 | static |
141 | bool lttng_ust_tp_validate_event_name(const struct lttng_ust_tracepoint *tp) | |
142 | { | |
143 | if (strlen(tp->provider_name) + 1 + | |
144 | strlen(tp->event_name) >= LTTNG_UST_TRACEPOINT_NAME_LEN_MAX) | |
145 | return false; | |
146 | return true; | |
147 | } | |
148 | ||
5e6df7ea | 149 | /* coverity[+alloc] */ |
efa2c591 | 150 | static void *allocate_probes(int count) |
f99be407 | 151 | { |
1a206094 SM |
152 | struct tp_probes *p = |
153 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
154 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
155 | return p == NULL ? NULL : p->probes; |
156 | } | |
157 | ||
5e6df7ea | 158 | /* coverity[+free : arg-0] */ |
efa2c591 | 159 | static void release_probes(void *old) |
f99be407 PMF |
160 | { |
161 | if (old) { | |
b728d87e | 162 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 163 | struct tp_probes, probes[0]); |
b653ddc1 | 164 | lttng_ust_urcu_synchronize_rcu(); |
909bc43f | 165 | free(tp_probes); |
f99be407 PMF |
166 | } |
167 | } | |
168 | ||
169 | static void debug_print_probes(struct tracepoint_entry *entry) | |
170 | { | |
171 | int i; | |
172 | ||
9dec086e | 173 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
174 | return; |
175 | ||
9dec086e NC |
176 | for (i = 0; entry->probes[i].func; i++) |
177 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
178 | } |
179 | ||
180 | static void * | |
9dec086e | 181 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 182 | void (*probe)(void), void *data) |
f99be407 PMF |
183 | { |
184 | int nr_probes = 0; | |
1a206094 | 185 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 186 | |
d7509147 MD |
187 | if (!probe) { |
188 | WARN_ON(1); | |
189 | return ERR_PTR(-EINVAL); | |
190 | } | |
f99be407 | 191 | debug_print_probes(entry); |
9dec086e | 192 | old = entry->probes; |
f99be407 PMF |
193 | if (old) { |
194 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
195 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
196 | if (old[nr_probes].func == probe && | |
197 | old[nr_probes].data == data) | |
f99be407 PMF |
198 | return ERR_PTR(-EEXIST); |
199 | } | |
200 | /* + 2 : one for new probe, one for NULL func */ | |
201 | new = allocate_probes(nr_probes + 2); | |
202 | if (new == NULL) | |
203 | return ERR_PTR(-ENOMEM); | |
204 | if (old) | |
1a206094 SM |
205 | memcpy(new, old, |
206 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
207 | new[nr_probes].func = probe; |
208 | new[nr_probes].data = data; | |
209 | new[nr_probes + 1].func = NULL; | |
f99be407 | 210 | entry->refcount = nr_probes + 1; |
9dec086e | 211 | entry->probes = new; |
f99be407 PMF |
212 | debug_print_probes(entry); |
213 | return old; | |
214 | } | |
215 | ||
216 | static void * | |
fbdeb5ec MD |
217 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
218 | void (*probe)(void), void *data) | |
f99be407 PMF |
219 | { |
220 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 221 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 222 | |
9dec086e | 223 | old = entry->probes; |
f99be407 PMF |
224 | |
225 | if (!old) | |
226 | return ERR_PTR(-ENOENT); | |
227 | ||
228 | debug_print_probes(entry); | |
229 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
230 | if (probe) { |
231 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
232 | if (old[nr_probes].func == probe && | |
233 | old[nr_probes].data == data) | |
234 | nr_del++; | |
235 | } | |
f99be407 PMF |
236 | } |
237 | ||
238 | if (nr_probes - nr_del == 0) { | |
239 | /* N -> 0, (N > 1) */ | |
9dec086e | 240 | entry->probes = NULL; |
f99be407 PMF |
241 | entry->refcount = 0; |
242 | debug_print_probes(entry); | |
243 | return old; | |
244 | } else { | |
245 | int j = 0; | |
246 | /* N -> M, (N > 1, M > 0) */ | |
247 | /* + 1 for NULL */ | |
248 | new = allocate_probes(nr_probes - nr_del + 1); | |
249 | if (new == NULL) | |
250 | return ERR_PTR(-ENOMEM); | |
9dec086e | 251 | for (i = 0; old[i].func; i++) |
956c6fab | 252 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 253 | new[j++] = old[i]; |
9dec086e | 254 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 255 | entry->refcount = nr_probes - nr_del; |
9dec086e | 256 | entry->probes = new; |
f99be407 PMF |
257 | } |
258 | debug_print_probes(entry); | |
259 | return old; | |
260 | } | |
261 | ||
262 | /* | |
263 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 264 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
265 | * Returns NULL if not present. |
266 | */ | |
34f7f142 | 267 | static struct tracepoint_entry *get_tracepoint(const char *provider_name, const char *event_name) |
f99be407 | 268 | { |
10c56168 DG |
269 | struct cds_hlist_head *head; |
270 | struct cds_hlist_node *node; | |
f99be407 | 271 | struct tracepoint_entry *e; |
ff412fb5 | 272 | uint32_t hash; |
f99be407 | 273 | |
34f7f142 MD |
274 | hash = jhash(provider_name, strlen(provider_name), 0) ^ |
275 | jhash(event_name, strlen(event_name), 0); | |
f99be407 | 276 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 277 | cds_hlist_for_each_entry(e, node, head, hlist) { |
34f7f142 | 278 | if (!strcmp(event_name, e->event_name) && !strcmp(provider_name, e->provider_name)) |
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 | */ |
34f7f142 | 288 | static struct tracepoint_entry *add_tracepoint(const char *provider_name, const char *event_name, |
67e5f391 | 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; |
2c05c691 | 294 | size_t sig_len = strlen(signature); |
34f7f142 MD |
295 | size_t sig_off, provider_name_off, event_name_off; |
296 | size_t provider_name_len = strlen(provider_name); | |
297 | size_t event_name_len = strlen(event_name); | |
ff412fb5 | 298 | uint32_t hash; |
f99be407 | 299 | |
34f7f142 MD |
300 | hash = jhash(provider_name, provider_name_len, 0) ^ |
301 | jhash(event_name, event_name_len, 0); | |
f99be407 | 302 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 303 | cds_hlist_for_each_entry(e, node, head, hlist) { |
34f7f142 MD |
304 | if (!strcmp(event_name, e->event_name) && !strcmp(provider_name, e->provider_name)) { |
305 | DBG("tracepoint \"%s:%s\" busy", provider_name, event_name); | |
f99be407 PMF |
306 | return ERR_PTR(-EEXIST); /* Already there */ |
307 | } | |
308 | } | |
2c05c691 | 309 | |
f99be407 | 310 | /* |
2c05c691 FD |
311 | * Using zmalloc here to allocate a variable length elements: name and |
312 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 313 | */ |
34f7f142 MD |
314 | provider_name_off = sizeof(struct tracepoint_entry); |
315 | event_name_off = provider_name_off + provider_name_len + 1; | |
316 | sig_off = event_name_off + event_name_len + 1; | |
2c05c691 | 317 | |
34f7f142 MD |
318 | e = zmalloc(sizeof(struct tracepoint_entry) + provider_name_len + 1 + |
319 | event_name_len + 1 + sig_len + 1); | |
f99be407 PMF |
320 | if (!e) |
321 | return ERR_PTR(-ENOMEM); | |
34f7f142 MD |
322 | e->provider_name = (char *) e + provider_name_off; |
323 | memcpy(e->provider_name, provider_name, provider_name_len + 1); | |
324 | e->provider_name[provider_name_len] = '\0'; | |
325 | ||
326 | e->event_name = (char *) e + event_name_off; | |
327 | memcpy(e->event_name, event_name, event_name_len + 1); | |
328 | e->event_name[event_name_len] = '\0'; | |
2c05c691 FD |
329 | |
330 | e->signature = (char *) e + sig_off; | |
331 | memcpy(e->signature, signature, sig_len + 1); | |
332 | e->signature[sig_len] = '\0'; | |
333 | ||
9dec086e | 334 | e->probes = NULL; |
f99be407 | 335 | e->refcount = 0; |
8a7ad54b | 336 | e->callsite_refcount = 0; |
2c05c691 | 337 | |
10c56168 | 338 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
339 | return e; |
340 | } | |
341 | ||
342 | /* | |
343 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 344 | * tracepoint mutex held. |
f99be407 | 345 | */ |
efa2c591 | 346 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 347 | { |
10c56168 | 348 | cds_hlist_del(&e->hlist); |
909bc43f | 349 | free(e); |
f99be407 PMF |
350 | } |
351 | ||
352 | /* | |
353 | * Sets the probe callback corresponding to one tracepoint. | |
354 | */ | |
355 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 356 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 357 | { |
34f7f142 MD |
358 | WARN_ON(strcmp((*entry)->provider_name, elem->provider_name) != 0); |
359 | WARN_ON(strcmp((*entry)->event_name, elem->event_name) != 0); | |
67e5f391 MD |
360 | /* |
361 | * Check that signatures match before connecting a probe to a | |
362 | * tracepoint. Warn the user if they don't. | |
363 | */ | |
364 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
365 | static int warned = 0; | |
366 | ||
367 | /* Only print once, don't flood console. */ | |
368 | if (!warned) { | |
369 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
34f7f142 MD |
370 | WARN("Tracepoint \"%s:%s\" signatures: call: \"%s\" vs probe: \"%s\".", |
371 | elem->provider_name, elem->event_name, elem->signature, (*entry)->signature); | |
67e5f391 MD |
372 | warned = 1; |
373 | } | |
374 | /* Don't accept connecting non-matching signatures. */ | |
375 | return; | |
376 | } | |
f99be407 PMF |
377 | |
378 | /* | |
0222e121 | 379 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
380 | * probe callbacks array is consistent before setting a pointer to it. |
381 | * This array is referenced by __DO_TRACE from | |
0222e121 | 382 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
383 | * is used. |
384 | */ | |
10544ee8 | 385 | lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 386 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
387 | } |
388 | ||
389 | /* | |
390 | * Disable a tracepoint and its probe callback. | |
391 | * Note: only waiting an RCU period after setting elem->call to the empty | |
392 | * function insures that the original callback is not used anymore. This insured | |
393 | * by preempt_disable around the call site. | |
394 | */ | |
1a206094 | 395 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 396 | { |
c082d14b | 397 | CMM_STORE_SHARED(elem->state, 0); |
10544ee8 | 398 | lttng_ust_rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
399 | } |
400 | ||
33f8ed87 MD |
401 | /* |
402 | * Add the callsite to the callsite hash table. Must be called with | |
403 | * tracepoint mutex held. | |
404 | */ | |
1a206094 | 405 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
406 | { |
407 | struct cds_hlist_head *head; | |
408 | struct callsite_entry *e; | |
33f8ed87 | 409 | uint32_t hash; |
8a7ad54b | 410 | struct tracepoint_entry *tp_entry; |
33f8ed87 | 411 | |
34f7f142 MD |
412 | if (!lttng_ust_tp_validate_event_name(tp)) { |
413 | WARN("Rejecting tracepoint name \"%s:%s\" which exceeds size limits of %u chars", | |
414 | tp->provider_name, tp->event_name, LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1); | |
415 | return; | |
33f8ed87 | 416 | } |
34f7f142 MD |
417 | hash = jhash(tp->provider_name, strlen(tp->provider_name), 0) ^ |
418 | jhash(tp->event_name, strlen(tp->event_name), 0); | |
33f8ed87 MD |
419 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; |
420 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 | 421 | if (!e) { |
34f7f142 | 422 | PERROR("Unable to add callsite for tracepoint \"%s:%s\"", tp->provider_name, tp->event_name); |
d6297168 MD |
423 | return; |
424 | } | |
33f8ed87 MD |
425 | cds_hlist_add_head(&e->hlist, head); |
426 | e->tp = tp; | |
427 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b | 428 | |
34f7f142 | 429 | tp_entry = get_tracepoint(tp->provider_name, tp->event_name); |
8a7ad54b IJ |
430 | if (!tp_entry) |
431 | return; | |
432 | tp_entry->callsite_refcount++; | |
2c05c691 | 433 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
434 | } |
435 | ||
436 | /* | |
437 | * Remove the callsite from the callsite hash table and from lib | |
438 | * callsite list. Must be called with tracepoint mutex held. | |
439 | */ | |
440 | static void remove_callsite(struct callsite_entry *e) | |
441 | { | |
8a7ad54b IJ |
442 | struct tracepoint_entry *tp_entry; |
443 | ||
34f7f142 | 444 | tp_entry = get_tracepoint(e->tp->provider_name, e->tp->event_name); |
8a7ad54b | 445 | if (tp_entry) { |
2c05c691 FD |
446 | if (e->tp_entry_callsite_ref) |
447 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
448 | if (tp_entry->callsite_refcount == 0) |
449 | disable_tracepoint(e->tp); | |
450 | } | |
33f8ed87 MD |
451 | cds_hlist_del(&e->hlist); |
452 | cds_list_del(&e->node); | |
453 | free(e); | |
454 | } | |
455 | ||
3469bbbe MD |
456 | /* |
457 | * Enable/disable all callsites based on the state of a specific | |
458 | * tracepoint entry. | |
459 | * Must be called with tracepoint mutex held. | |
460 | */ | |
34f7f142 | 461 | static void tracepoint_sync_callsites(const char *provider_name, const char *event_name) |
3469bbbe | 462 | { |
34f7f142 | 463 | struct tracepoint_entry *tp_entry; |
3469bbbe MD |
464 | struct cds_hlist_head *head; |
465 | struct cds_hlist_node *node; | |
466 | struct callsite_entry *e; | |
3469bbbe | 467 | uint32_t hash; |
3469bbbe | 468 | |
34f7f142 MD |
469 | tp_entry = get_tracepoint(provider_name, event_name); |
470 | hash = jhash(provider_name, strlen(provider_name), 0) ^ | |
471 | jhash(event_name, strlen(event_name), 0); | |
3469bbbe MD |
472 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; |
473 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 474 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe | 475 | |
34f7f142 MD |
476 | if (strcmp(event_name, tp->event_name)) |
477 | continue; | |
478 | if (strcmp(provider_name, tp->provider_name)) | |
3469bbbe MD |
479 | continue; |
480 | if (tp_entry) { | |
2c05c691 FD |
481 | if (!e->tp_entry_callsite_ref) { |
482 | tp_entry->callsite_refcount++; | |
483 | e->tp_entry_callsite_ref = true; | |
484 | } | |
3469bbbe MD |
485 | set_tracepoint(&tp_entry, tp, |
486 | !!tp_entry->refcount); | |
487 | } else { | |
488 | disable_tracepoint(tp); | |
2c05c691 | 489 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
490 | } |
491 | } | |
492 | } | |
493 | ||
f99be407 PMF |
494 | /** |
495 | * tracepoint_update_probe_range - Update a probe range | |
496 | * @begin: beginning of the range | |
497 | * @end: end of the range | |
498 | * | |
499 | * Updates the probe callback corresponding to a range of tracepoints. | |
500 | */ | |
b27f8e75 | 501 | static |
1a206094 SM |
502 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
503 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 504 | { |
1a206094 | 505 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
506 | struct tracepoint_entry *mark_entry; |
507 | ||
f99be407 | 508 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
509 | if (!*iter) |
510 | continue; /* skip dummy */ | |
34f7f142 MD |
511 | if (!(*iter)->provider_name || !(*iter)->event_name) { |
512 | disable_tracepoint(*iter); | |
513 | continue; | |
514 | } | |
515 | if (!lttng_ust_tp_validate_event_name(*iter)) { | |
516 | WARN("Rejecting tracepoint name \"%s:%s\" which exceeds size limits of %u chars", | |
517 | (*iter)->provider_name, (*iter)->event_name, LTTNG_UST_TRACEPOINT_NAME_LEN_MAX - 1); | |
f218ff28 | 518 | disable_tracepoint(*iter); |
9dec086e NC |
519 | continue; |
520 | } | |
34f7f142 | 521 | mark_entry = get_tracepoint((*iter)->provider_name, (*iter)->event_name); |
f99be407 | 522 | if (mark_entry) { |
f218ff28 | 523 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
524 | !!mark_entry->refcount); |
525 | } else { | |
f218ff28 | 526 | disable_tracepoint(*iter); |
f99be407 PMF |
527 | } |
528 | } | |
f99be407 PMF |
529 | } |
530 | ||
5da10905 | 531 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 532 | { |
5da10905 MD |
533 | tracepoint_update_probe_range(lib->tracepoints_start, |
534 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
535 | } |
536 | ||
3469bbbe MD |
537 | static void lib_register_callsites(struct tracepoint_lib *lib) |
538 | { | |
1a206094 SM |
539 | struct lttng_ust_tracepoint * const *begin; |
540 | struct lttng_ust_tracepoint * const *end; | |
541 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
542 | |
543 | begin = lib->tracepoints_start; | |
544 | end = lib->tracepoints_start + lib->tracepoints_count; | |
545 | ||
546 | for (iter = begin; iter < end; iter++) { | |
547 | if (!*iter) | |
548 | continue; /* skip dummy */ | |
34f7f142 | 549 | if (!(*iter)->provider_name || !(*iter)->event_name) { |
3469bbbe MD |
550 | continue; |
551 | } | |
60d87029 | 552 | add_callsite(lib, *iter); |
3469bbbe MD |
553 | } |
554 | } | |
555 | ||
556 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
557 | { | |
558 | struct callsite_entry *callsite, *tmp; | |
559 | ||
560 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
561 | remove_callsite(callsite); | |
562 | } | |
563 | ||
f99be407 PMF |
564 | /* |
565 | * Update probes, removing the faulty probes. | |
566 | */ | |
567 | static void tracepoint_update_probes(void) | |
568 | { | |
5da10905 MD |
569 | struct tracepoint_lib *lib; |
570 | ||
b27f8e75 | 571 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
572 | cds_list_for_each_entry(lib, &libs, list) |
573 | lib_update_tracepoints(lib); | |
f99be407 PMF |
574 | } |
575 | ||
1a206094 | 576 | static struct lttng_ust_tracepoint_probe * |
34f7f142 MD |
577 | tracepoint_add_probe(const char *provider_name, const char *event_name, |
578 | void (*probe)(void), void *data, const char *signature) | |
f99be407 PMF |
579 | { |
580 | struct tracepoint_entry *entry; | |
1a206094 | 581 | struct lttng_ust_tracepoint_probe *old; |
f99be407 | 582 | |
34f7f142 | 583 | entry = get_tracepoint(provider_name, event_name); |
2c05c691 FD |
584 | if (entry) { |
585 | if (strcmp(entry->signature, signature) != 0) { | |
34f7f142 MD |
586 | ERR("Tracepoint \"%s:%s\": tracepoint and probe signature do not match: \"%s\" vs \"%s\".", |
587 | provider_name, event_name, entry->signature, signature); | |
2c05c691 FD |
588 | return ERR_PTR(-EINVAL); |
589 | } | |
590 | } else { | |
34f7f142 | 591 | entry = add_tracepoint(provider_name, event_name, signature); |
f99be407 | 592 | if (IS_ERR(entry)) |
1a206094 | 593 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 594 | } |
9dec086e | 595 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
596 | if (IS_ERR(old) && !entry->refcount) |
597 | remove_tracepoint(entry); | |
598 | return old; | |
599 | } | |
600 | ||
baa1e0bc MD |
601 | static void tracepoint_release_queue_add_old_probes(void *old) |
602 | { | |
603 | release_queue_need_update = 1; | |
604 | if (old) { | |
605 | struct tp_probes *tp_probes = caa_container_of(old, | |
606 | struct tp_probes, probes[0]); | |
607 | cds_list_add(&tp_probes->u.list, &release_queue); | |
608 | } | |
609 | } | |
610 | ||
67418c35 MD |
611 | /* |
612 | * Use a symbol of the previous ABI to detect if liblttng-ust-tracepoint.so.0 | |
613 | * is loaded in the current process. | |
614 | */ | |
615 | #define LTTNG_UST_TRACEPOINT_SONAME_0_SYM "tracepoint_unregister_lib" | |
616 | ||
617 | static | |
618 | void lttng_ust_tracepoint_check_soname_0(void) | |
619 | { | |
620 | if (!dlsym(RTLD_DEFAULT, LTTNG_UST_TRACEPOINT_SONAME_0_SYM)) | |
621 | return; | |
622 | ||
623 | CRIT("Incompatible library ABIs detected within the same process. " | |
624 | "The process is likely linked against different major soname of LTTng-UST which is unsupported. " | |
625 | "The detection was triggered by lookup of ABI 0 symbol \"%s\" in the Global Symbol Table\n", | |
626 | LTTNG_UST_TRACEPOINT_SONAME_0_SYM); | |
627 | } | |
628 | ||
629 | /* | |
630 | * Expose a canary symbol of the previous ABI to ensure we catch uses of a | |
631 | * liblttng-ust-tracepoint.so.0 dlopen'd after .so.1 has been loaded. Use a | |
632 | * different symbol than the detection code to ensure we don't detect ourself. | |
633 | */ | |
634 | int tracepoint_register_lib(void *arg0 __attribute__((unused)), int arg1 __attribute__((unused))); | |
635 | int tracepoint_register_lib(void *arg0 __attribute__((unused)), int arg1 __attribute__((unused))) | |
636 | { | |
637 | CRIT("Incompatible library ABIs detected within the same process. " | |
638 | "The process is likely linked against different major soname of LTTng-UST which is unsupported. " | |
639 | "The detection was triggered by canary symbol \"%s\"\n", __func__); | |
640 | ||
641 | return -1; | |
642 | } | |
643 | ||
f99be407 | 644 | /** |
9b34a2b2 | 645 | * lttng_ust_tracepoint_provider_register - Connect a probe to a tracepoint |
34f7f142 MD |
646 | * @name: tracepoint provider name |
647 | * @name: tracepoint event name | |
f99be407 PMF |
648 | * @probe: probe handler |
649 | * | |
650 | * Returns 0 if ok, error value on error. | |
651 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 652 | * Called with the tracepoint mutex held. |
f99be407 | 653 | */ |
9b34a2b2 | 654 | int lttng_ust_tracepoint_provider_register(const char *provider_name, const char *event_name, |
34f7f142 | 655 | void (*probe)(void), void *data, const char *signature) |
f99be407 PMF |
656 | { |
657 | void *old; | |
8792fbae | 658 | int ret = 0; |
f99be407 | 659 | |
67418c35 MD |
660 | /* |
661 | * Check if we find a symbol of the previous ABI in the current process | |
662 | * as different ABIs of liblttng-ust can't co-exist in a process. If we | |
663 | * do so, emit a critical log message which will also abort if the | |
664 | * LTTNG_UST_ABORT_ON_CRITICAL environment variable is set. | |
665 | */ | |
666 | lttng_ust_tracepoint_check_soname_0(); | |
667 | ||
34f7f142 | 668 | DBG("Registering probe to tracepoint \"%s:%s\"", provider_name, event_name); |
05780d81 | 669 | |
8792fbae | 670 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 671 | old = tracepoint_add_probe(provider_name, event_name, probe, data, signature); |
8792fbae MD |
672 | if (IS_ERR(old)) { |
673 | ret = PTR_ERR(old); | |
674 | goto end; | |
675 | } | |
f99be407 | 676 | |
34f7f142 | 677 | tracepoint_sync_callsites(provider_name, event_name); |
f99be407 | 678 | release_probes(old); |
8792fbae MD |
679 | end: |
680 | pthread_mutex_unlock(&tracepoint_mutex); | |
681 | return ret; | |
f99be407 | 682 | } |
f99be407 | 683 | |
baa1e0bc | 684 | /* |
0274f7f2 | 685 | * Caller needs to invoke lttng_ust_tracepoint_probe_release_queue() after |
d10a2205 | 686 | * calling lttng_ust_tp_probe_register_queue_release() one or multiple |
baa1e0bc MD |
687 | * times to ensure it does not leak memory. |
688 | */ | |
34f7f142 | 689 | int lttng_ust_tp_probe_register_queue_release(const char *provider_name, const char *event_name, |
baa1e0bc MD |
690 | void (*probe)(void), void *data, const char *signature) |
691 | { | |
692 | void *old; | |
693 | int ret = 0; | |
694 | ||
34f7f142 | 695 | DBG("Registering probe to tracepoint \"%s:%s\". Queuing release.", provider_name, event_name); |
baa1e0bc MD |
696 | |
697 | pthread_mutex_lock(&tracepoint_mutex); | |
34f7f142 | 698 | old = tracepoint_add_probe(provider_name, event_name, probe, data, signature); |
baa1e0bc MD |
699 | if (IS_ERR(old)) { |
700 | ret = PTR_ERR(old); | |
701 | goto end; | |
702 | } | |
703 | ||
34f7f142 | 704 | tracepoint_sync_callsites(provider_name, event_name); |
baa1e0bc MD |
705 | tracepoint_release_queue_add_old_probes(old); |
706 | end: | |
707 | pthread_mutex_unlock(&tracepoint_mutex); | |
708 | return ret; | |
709 | } | |
710 | ||
34f7f142 MD |
711 | static void *tracepoint_remove_probe(const char *provider_name, const char *event_name, |
712 | void (*probe)(void), void *data) | |
f99be407 PMF |
713 | { |
714 | struct tracepoint_entry *entry; | |
715 | void *old; | |
716 | ||
34f7f142 | 717 | entry = get_tracepoint(provider_name, event_name); |
f99be407 PMF |
718 | if (!entry) |
719 | return ERR_PTR(-ENOENT); | |
9dec086e | 720 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
721 | if (IS_ERR(old)) |
722 | return old; | |
723 | if (!entry->refcount) | |
724 | remove_tracepoint(entry); | |
725 | return old; | |
726 | } | |
727 | ||
728 | /** | |
729 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
34f7f142 MD |
730 | * @provider_name: tracepoint provider name |
731 | * @event_name: tracepoint event name | |
f99be407 | 732 | * @probe: probe function pointer |
9dec086e | 733 | * @probe: probe data pointer |
f99be407 | 734 | */ |
9b34a2b2 | 735 | int lttng_ust_tracepoint_provider_unregister(const char *provider_name, const char *event_name, |
34f7f142 | 736 | void (*probe)(void), void *data) |
f99be407 PMF |
737 | { |
738 | void *old; | |
8792fbae | 739 | int ret = 0; |
f99be407 | 740 | |
34f7f142 | 741 | DBG("Un-registering probe \"%s:%s\" from tracepoint %p", provider_name, event_name, probe); |
05780d81 | 742 | |
8792fbae | 743 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 744 | old = tracepoint_remove_probe(provider_name, event_name, probe, data); |
8792fbae MD |
745 | if (IS_ERR(old)) { |
746 | ret = PTR_ERR(old); | |
747 | goto end; | |
748 | } | |
34f7f142 | 749 | tracepoint_sync_callsites(provider_name, event_name); |
f99be407 | 750 | release_probes(old); |
8792fbae MD |
751 | end: |
752 | pthread_mutex_unlock(&tracepoint_mutex); | |
753 | return ret; | |
f99be407 | 754 | } |
f99be407 | 755 | |
baa1e0bc | 756 | /* |
0274f7f2 | 757 | * Caller needs to invoke lttng_ust_tracepoint_probe_release_queue() after |
d10a2205 | 758 | * calling lttng_ust_tp_probe_unregister_queue_release() one or multiple |
baa1e0bc MD |
759 | * times to ensure it does not leak memory. |
760 | */ | |
34f7f142 | 761 | int lttng_ust_tp_probe_unregister_queue_release(const char *provider_name, const char *event_name, |
baa1e0bc MD |
762 | void (*probe)(void), void *data) |
763 | { | |
764 | void *old; | |
765 | int ret = 0; | |
766 | ||
34f7f142 | 767 | DBG("Un-registering probe from tracepoint \"%s:%s\". Queuing release.", provider_name, event_name); |
baa1e0bc MD |
768 | |
769 | pthread_mutex_lock(&tracepoint_mutex); | |
34f7f142 | 770 | old = tracepoint_remove_probe(provider_name, event_name, probe, data); |
baa1e0bc MD |
771 | if (IS_ERR(old)) { |
772 | ret = PTR_ERR(old); | |
773 | goto end; | |
774 | } | |
34f7f142 | 775 | tracepoint_sync_callsites(provider_name, event_name); |
baa1e0bc MD |
776 | tracepoint_release_queue_add_old_probes(old); |
777 | end: | |
778 | pthread_mutex_unlock(&tracepoint_mutex); | |
779 | return ret; | |
780 | } | |
781 | ||
d10a2205 | 782 | void lttng_ust_tp_probe_prune_release_queue(void) |
baa1e0bc MD |
783 | { |
784 | CDS_LIST_HEAD(release_probes); | |
785 | struct tp_probes *pos, *next; | |
786 | ||
787 | DBG("Release queue of unregistered tracepoint probes."); | |
788 | ||
789 | pthread_mutex_lock(&tracepoint_mutex); | |
790 | if (!release_queue_need_update) | |
791 | goto end; | |
792 | if (!cds_list_empty(&release_queue)) | |
793 | cds_list_replace_init(&release_queue, &release_probes); | |
794 | release_queue_need_update = 0; | |
795 | ||
796 | /* Wait for grace period between all sync_callsites and free. */ | |
b653ddc1 | 797 | lttng_ust_urcu_synchronize_rcu(); |
baa1e0bc MD |
798 | |
799 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
800 | cds_list_del(&pos->u.list); | |
801 | free(pos); | |
802 | } | |
803 | end: | |
804 | pthread_mutex_unlock(&tracepoint_mutex); | |
805 | } | |
806 | ||
f99be407 PMF |
807 | static void tracepoint_add_old_probes(void *old) |
808 | { | |
809 | need_update = 1; | |
810 | if (old) { | |
b728d87e | 811 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 812 | struct tp_probes, probes[0]); |
0222e121 | 813 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
814 | } |
815 | } | |
816 | ||
817 | /** | |
818 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
819 | * @name: tracepoint name | |
820 | * @probe: probe handler | |
821 | * | |
822 | * caller must call tracepoint_probe_update_all() | |
823 | */ | |
34f7f142 MD |
824 | int tracepoint_probe_register_noupdate(const char *provider_name, const char *event_name, |
825 | void (*probe)(void), void *data, const char *signature) | |
f99be407 PMF |
826 | { |
827 | void *old; | |
8792fbae | 828 | int ret = 0; |
f99be407 | 829 | |
8792fbae | 830 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 831 | old = tracepoint_add_probe(provider_name, event_name, probe, data, signature); |
f99be407 | 832 | if (IS_ERR(old)) { |
8792fbae MD |
833 | ret = PTR_ERR(old); |
834 | goto end; | |
f99be407 PMF |
835 | } |
836 | tracepoint_add_old_probes(old); | |
8792fbae MD |
837 | end: |
838 | pthread_mutex_unlock(&tracepoint_mutex); | |
839 | return ret; | |
f99be407 | 840 | } |
f99be407 PMF |
841 | |
842 | /** | |
843 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
844 | * @name: tracepoint name | |
845 | * @probe: probe function pointer | |
846 | * | |
847 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 848 | * Called with the tracepoint mutex held. |
f99be407 | 849 | */ |
34f7f142 MD |
850 | int tracepoint_probe_unregister_noupdate(const char *provider_name, const char *event_name, |
851 | void (*probe)(void), void *data) | |
f99be407 PMF |
852 | { |
853 | void *old; | |
8792fbae | 854 | int ret = 0; |
f99be407 | 855 | |
34f7f142 | 856 | DBG("Un-registering probe from tracepoint \"%s:%s\"", provider_name, event_name); |
05780d81 | 857 | |
8792fbae | 858 | pthread_mutex_lock(&tracepoint_mutex); |
34f7f142 | 859 | old = tracepoint_remove_probe(provider_name, event_name, probe, data); |
f99be407 | 860 | if (IS_ERR(old)) { |
8792fbae MD |
861 | ret = PTR_ERR(old); |
862 | goto end; | |
f99be407 PMF |
863 | } |
864 | tracepoint_add_old_probes(old); | |
8792fbae MD |
865 | end: |
866 | pthread_mutex_unlock(&tracepoint_mutex); | |
867 | return ret; | |
f99be407 | 868 | } |
f99be407 PMF |
869 | |
870 | /** | |
871 | * tracepoint_probe_update_all - update tracepoints | |
872 | */ | |
873 | void tracepoint_probe_update_all(void) | |
874 | { | |
0222e121 | 875 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
876 | struct tp_probes *pos, *next; |
877 | ||
8792fbae | 878 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 879 | if (!need_update) { |
8792fbae | 880 | goto end; |
f99be407 | 881 | } |
0222e121 MD |
882 | if (!cds_list_empty(&old_probes)) |
883 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 884 | need_update = 0; |
f99be407 PMF |
885 | |
886 | tracepoint_update_probes(); | |
baa1e0bc | 887 | /* Wait for grace period between update_probes and free. */ |
b653ddc1 | 888 | lttng_ust_urcu_synchronize_rcu(); |
0222e121 MD |
889 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
890 | cds_list_del(&pos->u.list); | |
909bc43f | 891 | free(pos); |
f99be407 | 892 | } |
8792fbae MD |
893 | end: |
894 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 895 | } |
f99be407 | 896 | |
1a206094 SM |
897 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
898 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 899 | { |
f218ff28 | 900 | if (new_tracepoint_cb) { |
1a206094 | 901 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 902 | |
b27f8e75 | 903 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
904 | if (*t) |
905 | new_tracepoint_cb(*t); | |
474d745f PMF |
906 | } |
907 | } | |
f99be407 | 908 | } |
f99be407 | 909 | |
10544ee8 MD |
910 | /* |
911 | * tracepoint_{un,}register_lib is meant to be looked up by instrumented | |
912 | * applications through dlsym(). If found, those can register their | |
913 | * tracepoints, else those tracepoints will not be available for | |
914 | * tracing. The number at the end of those symbols acts as a major | |
915 | * version for tracepoints. | |
916 | * | |
917 | * Older instrumented applications should still work with newer | |
918 | * liblttng-ust, but it is fine that instrumented applications compiled | |
919 | * against recent liblttng-ust headers require a recent liblttng-ust | |
920 | * runtime for those tracepoints to be taken into account. | |
921 | */ | |
14227bde | 922 | int lttng_ust_tracepoint_module_register(struct lttng_ust_tracepoint * const *tracepoints_start, |
4b4a1337 | 923 | int tracepoints_count); |
14227bde | 924 | int lttng_ust_tracepoint_module_register(struct lttng_ust_tracepoint * const *tracepoints_start, |
10544ee8 | 925 | int tracepoints_count) |
474d745f | 926 | { |
b467f7a7 | 927 | struct tracepoint_lib *pl, *iter; |
474d745f | 928 | |
25afb7ac | 929 | lttng_ust_tp_init(); |
edaa1431 | 930 | |
1dba3e6c | 931 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
932 | if (!pl) { |
933 | PERROR("Unable to register tracepoint lib"); | |
934 | return -1; | |
935 | } | |
474d745f PMF |
936 | pl->tracepoints_start = tracepoints_start; |
937 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 938 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 939 | |
8792fbae | 940 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
941 | /* |
942 | * We sort the libs by struct lib pointer address. | |
943 | */ | |
944 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
945 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
946 | if (iter < pl) { | |
947 | /* We belong to the location right after iter. */ | |
948 | cds_list_add(&pl->list, &iter->list); | |
949 | goto lib_added; | |
950 | } | |
951 | } | |
952 | /* We should be added at the head of the list */ | |
0222e121 | 953 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 954 | lib_added: |
474d745f | 955 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 956 | lib_register_callsites(pl); |
5da10905 | 957 | lib_update_tracepoints(pl); |
8792fbae | 958 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 959 | |
1fcf7ad7 MD |
960 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
961 | tracepoints_start, tracepoints_count); | |
c6e6343c | 962 | if (lttng_ust_logging_debug_enabled()) { |
05780d81 MD |
963 | int i; |
964 | ||
965 | for (i = 0; i < tracepoints_count; i++) { | |
34f7f142 MD |
966 | if (!lttng_ust_tp_validate_event_name(tracepoints_start[i])) |
967 | continue; | |
968 | DBG("registered tracepoint: \"%s:%s\"", | |
969 | tracepoints_start[i]->provider_name, | |
970 | tracepoints_start[i]->event_name); | |
05780d81 MD |
971 | } |
972 | } | |
9dec086e | 973 | |
474d745f PMF |
974 | return 0; |
975 | } | |
976 | ||
14227bde MJ |
977 | int lttng_ust_tracepoint_module_unregister(struct lttng_ust_tracepoint * const *tracepoints_start); |
978 | int lttng_ust_tracepoint_module_unregister(struct lttng_ust_tracepoint * const *tracepoints_start) | |
474d745f | 979 | { |
24b6668c PMF |
980 | struct tracepoint_lib *lib; |
981 | ||
8792fbae | 982 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 983 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
984 | if (lib->tracepoints_start != tracepoints_start) |
985 | continue; | |
1622ba22 | 986 | |
3469bbbe MD |
987 | cds_list_del(&lib->list); |
988 | /* | |
8a7ad54b IJ |
989 | * Unregistering a callsite also decreases the |
990 | * callsite reference count of the corresponding | |
991 | * tracepoint, and disables the tracepoint if | |
992 | * the reference count drops to zero. | |
3469bbbe | 993 | */ |
3469bbbe MD |
994 | lib_unregister_callsites(lib); |
995 | DBG("just unregistered a tracepoints section from %p", | |
996 | lib->tracepoints_start); | |
997 | free(lib); | |
998 | break; | |
24b6668c | 999 | } |
8792fbae | 1000 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
1001 | return 0; |
1002 | } | |
b27f8e75 | 1003 | |
5517d34d MD |
1004 | /* |
1005 | * Report in debug message whether the compiler correctly supports weak | |
1006 | * hidden symbols. This test checks that the address associated with two | |
1007 | * weak symbols with hidden visibility is the same when declared within | |
1008 | * two compile units part of the same module. | |
1009 | */ | |
1010 | static void check_weak_hidden(void) | |
1011 | { | |
b0e63efd | 1012 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
0274f7f2 | 1013 | <tng_ust_tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? |
b0e63efd MD |
1014 | "SAME address" : |
1015 | "DIFFERENT addresses"); | |
1016 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
0274f7f2 | 1017 | <tng_ust_tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? |
b0e63efd MD |
1018 | "SAME address" : |
1019 | "DIFFERENT addresses"); | |
1020 | 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 | 1021 | <tng_ust_tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? |
b0e63efd MD |
1022 | "SAME address" : |
1023 | "DIFFERENT addresses"); | |
5517d34d MD |
1024 | } |
1025 | ||
25afb7ac | 1026 | void lttng_ust_tp_init(void) |
b27f8e75 | 1027 | { |
edaa1431 MD |
1028 | if (uatomic_xchg(&initialized, 1) == 1) |
1029 | return; | |
c6e6343c | 1030 | lttng_ust_logging_init(); |
fca97dfd | 1031 | lttng_ust_common_ctor(); |
5517d34d | 1032 | check_weak_hidden(); |
b27f8e75 MD |
1033 | } |
1034 | ||
25afb7ac | 1035 | void lttng_ust_tp_exit(void) |
b27f8e75 | 1036 | { |
17dfb34b | 1037 | initialized = 0; |
b27f8e75 | 1038 | } |
40b2b5a4 MD |
1039 | |
1040 | /* | |
1041 | * Create the wrapper symbols. | |
1042 | */ | |
251c9f75 MJ |
1043 | #undef lttng_ust_tp_rcu_read_lock |
1044 | #undef lttng_ust_tp_rcu_read_unlock | |
1045 | #undef lttng_ust_tp_rcu_dereference | |
40b2b5a4 | 1046 | |
251c9f75 MJ |
1047 | void lttng_ust_tp_rcu_read_lock(void); |
1048 | void lttng_ust_tp_rcu_read_lock(void) | |
40b2b5a4 | 1049 | { |
10544ee8 | 1050 | lttng_ust_urcu_read_lock(); |
40b2b5a4 MD |
1051 | } |
1052 | ||
251c9f75 MJ |
1053 | void lttng_ust_tp_rcu_read_unlock(void); |
1054 | void lttng_ust_tp_rcu_read_unlock(void) | |
40b2b5a4 | 1055 | { |
10544ee8 | 1056 | lttng_ust_urcu_read_unlock(); |
40b2b5a4 MD |
1057 | } |
1058 | ||
251c9f75 MJ |
1059 | void *lttng_ust_tp_rcu_dereference_sym(void *p); |
1060 | void *lttng_ust_tp_rcu_dereference_sym(void *p) | |
40b2b5a4 | 1061 | { |
10544ee8 | 1062 | return lttng_ust_rcu_dereference(p); |
40b2b5a4 | 1063 | } |
0fd0de10 FD |
1064 | |
1065 | /* | |
1066 | * Programs that have threads that survive after they exit, and therefore call | |
1067 | * library destructors, should disable the tracepoint destructors by calling | |
096c06e5 | 1068 | * lttng_ust_tp_disable_destructors(). This will leak the tracepoint |
0fd0de10 FD |
1069 | * instrumentation library shared object, leaving its teardown to the operating |
1070 | * system process teardown. | |
1071 | * | |
1072 | * To access and/or modify this value, users need to use a combination of | |
1073 | * dlopen(3) and dlsym(3) to get an handle on the | |
096c06e5 | 1074 | * lttng_ust_tp_disable_destructors and lttng_ust_tp_get_destructors_state symbols below. |
0fd0de10 | 1075 | */ |
096c06e5 MJ |
1076 | void lttng_ust_tp_disable_destructors(void); |
1077 | void lttng_ust_tp_disable_destructors(void) | |
0fd0de10 FD |
1078 | { |
1079 | uatomic_set(&tracepoint_destructors_state, 0); | |
1080 | } | |
1081 | ||
1082 | /* | |
1083 | * Returns 1 if the destructors are enabled and should be executed. | |
1084 | * Returns 0 if the destructors are disabled. | |
1085 | */ | |
096c06e5 MJ |
1086 | int lttng_ust_tp_get_destructors_state(void); |
1087 | int lttng_ust_tp_get_destructors_state(void) | |
0fd0de10 FD |
1088 | { |
1089 | return uatomic_read(&tracepoint_destructors_state); | |
1090 | } |