Commit | Line | Data |
---|---|---|
67337c4a MD |
1 | // SPDX-License-Identifier: MIT |
2 | /* | |
3 | * Copyright 2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | */ | |
5 | ||
6 | #include <side/trace.h> | |
7 | #include <string.h> | |
b1bf768c | 8 | #include <assert.h> |
a125f217 MD |
9 | #include <pthread.h> |
10 | #include <unistd.h> | |
67337c4a MD |
11 | |
12 | #include "rcu.h" | |
13 | #include "list.h" | |
873bbf16 | 14 | #include "rculist.h" |
67337c4a | 15 | |
871851e7 | 16 | /* Top 8 bits reserved for shared tracer use. */ |
67337c4a | 17 | #if SIDE_BITS_PER_LONG == 64 |
871851e7 MD |
18 | # define SIDE_EVENT_ENABLED_SHARED_MASK 0xFF00000000000000ULL |
19 | # define SIDE_EVENT_ENABLED_SHARED_USER_EVENT_MASK 0x8000000000000000ULL | |
20 | # define SIDE_EVENT_ENABLED_SHARED_PTRACE_MASK 0x4000000000000000ULL | |
67337c4a | 21 | |
871851e7 MD |
22 | /* Allow 2^56 private tracer references on an event. */ |
23 | # define SIDE_EVENT_ENABLED_PRIVATE_MASK 0x00FFFFFFFFFFFFFFULL | |
67337c4a | 24 | #else |
871851e7 MD |
25 | # define SIDE_EVENT_ENABLED_SHARED_MASK 0xFF000000UL |
26 | # define SIDE_EVENT_ENABLED_SHARED_USER_EVENT_MASK 0x80000000UL | |
27 | # define SIDE_EVENT_ENABLED_SHARED_PTRACE_MASK 0x40000000UL | |
67337c4a | 28 | |
871851e7 MD |
29 | /* Allow 2^24 private tracer references on an event. */ |
30 | # define SIDE_EVENT_ENABLED_PRIVATE_MASK 0x00FFFFFFUL | |
67337c4a MD |
31 | #endif |
32 | ||
bffe9ae3 MD |
33 | #define SIDE_KEY_RESERVED_RANGE_END 0x8 |
34 | ||
35 | /* Key 0x0 is reserved to match all. */ | |
36 | #define SIDE_KEY_MATCH_ALL 0x0 | |
871851e7 | 37 | /* Key 0x1 is reserved for user event. */ |
bffe9ae3 | 38 | #define SIDE_KEY_USER_EVENT 0x1 |
871851e7 | 39 | /* Key 0x2 is reserved for ptrace. */ |
bffe9ae3 | 40 | #define SIDE_KEY_PTRACE 0x2 |
871851e7 | 41 | |
67337c4a MD |
42 | struct side_events_register_handle { |
43 | struct side_list_node node; | |
44 | struct side_event_description **events; | |
45 | uint32_t nr_events; | |
46 | }; | |
47 | ||
48 | struct side_tracer_handle { | |
49 | struct side_list_node node; | |
50 | void (*cb)(enum side_tracer_notification notif, | |
51 | struct side_event_description **events, uint32_t nr_events, void *priv); | |
52 | void *priv; | |
53 | }; | |
54 | ||
bffe9ae3 MD |
55 | struct side_statedump_notification { |
56 | struct side_list_node node; | |
57 | uint64_t key; | |
58 | }; | |
59 | ||
f0b01832 | 60 | struct side_statedump_request_handle { |
bffe9ae3 MD |
61 | struct side_list_node node; /* Statedump request RCU list node. */ |
62 | struct side_list_head notification_queue; /* Queue of struct side_statedump_notification */ | |
f0b01832 | 63 | void (*cb)(void); |
bffe9ae3 MD |
64 | char *name; |
65 | enum side_statedump_mode mode; | |
f0b01832 MD |
66 | }; |
67 | ||
867b4725 MD |
68 | struct side_callback { |
69 | union { | |
70 | void (*call)(const struct side_event_description *desc, | |
71 | const struct side_arg_vec *side_arg_vec, | |
72 | void *priv); | |
73 | void (*call_variadic)(const struct side_event_description *desc, | |
74 | const struct side_arg_vec *side_arg_vec, | |
75 | const struct side_arg_dynamic_struct *var_struct, | |
76 | void *priv); | |
77 | } u; | |
78 | void *priv; | |
bffe9ae3 | 79 | uint64_t key; |
867b4725 MD |
80 | }; |
81 | ||
a125f217 MD |
82 | enum agent_thread_state { |
83 | AGENT_THREAD_STATE_BLOCKED = 0, | |
84 | AGENT_THREAD_STATE_HANDLE_REQUEST = (1 << 0), | |
85 | AGENT_THREAD_STATE_EXIT = (1 << 1), | |
86 | }; | |
87 | ||
88 | struct statedump_agent_thread { | |
89 | long ref; | |
90 | pthread_t id; | |
91 | enum agent_thread_state state; | |
92 | }; | |
93 | ||
873bbf16 | 94 | static struct side_rcu_gp_state event_rcu_gp, statedump_rcu_gp; |
67337c4a MD |
95 | |
96 | /* | |
97 | * Lazy initialization for early use within library constructors. | |
98 | */ | |
99 | static bool initialized; | |
100 | /* | |
101 | * Do not register/unregister any more events after destructor. | |
102 | */ | |
103 | static bool finalized; | |
104 | ||
105 | /* | |
106 | * Recursive mutex to allow tracer callbacks to use the side API. | |
107 | */ | |
873bbf16 MD |
108 | static pthread_mutex_t side_event_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; |
109 | static pthread_mutex_t side_statedump_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; | |
bffe9ae3 MD |
110 | static pthread_mutex_t side_key_lock = PTHREAD_MUTEX_INITIALIZER; |
111 | ||
112 | /* Dynamic tracer key allocation. */ | |
113 | static uint64_t side_key_next = SIDE_KEY_RESERVED_RANGE_END; | |
67337c4a | 114 | |
a125f217 MD |
115 | static struct statedump_agent_thread statedump_agent_thread; |
116 | ||
67337c4a MD |
117 | static DEFINE_SIDE_LIST_HEAD(side_events_list); |
118 | static DEFINE_SIDE_LIST_HEAD(side_tracer_list); | |
bffe9ae3 MD |
119 | |
120 | /* | |
121 | * The statedump request list is a RCU list to allow the agent thread to | |
122 | * iterate over this list with a RCU read-side lock. | |
123 | */ | |
f0b01832 | 124 | static DEFINE_SIDE_LIST_HEAD(side_statedump_list); |
67337c4a | 125 | |
74be90b7 MD |
126 | /* |
127 | * Callback filter key for state dump. | |
128 | */ | |
bffe9ae3 | 129 | static __thread uint64_t filter_key = SIDE_KEY_MATCH_ALL; |
74be90b7 | 130 | |
67337c4a MD |
131 | /* |
132 | * The empty callback has a NULL function callback pointer, which stops | |
133 | * iteration on the array of callbacks immediately. | |
134 | */ | |
867b4725 | 135 | const char side_empty_callback[sizeof(struct side_callback)]; |
67337c4a | 136 | |
bffe9ae3 MD |
137 | side_static_event(side_statedump_begin, "side", "statedump_begin", |
138 | SIDE_LOGLEVEL_INFO, side_field_list(side_field_string("name"))); | |
139 | side_static_event(side_statedump_end, "side", "statedump_end", | |
140 | SIDE_LOGLEVEL_INFO, side_field_list(side_field_string("name"))); | |
141 | ||
871851e7 MD |
142 | /* |
143 | * side_ptrace_hook is a place holder for a debugger breakpoint. | |
144 | * var_struct is NULL if not variadic. | |
145 | */ | |
146 | void side_ptrace_hook(const struct side_event_state *event_state __attribute__((unused)), | |
147 | const struct side_arg_vec *side_arg_vec __attribute__((unused)), | |
148 | const struct side_arg_dynamic_struct *var_struct __attribute__((unused))) | |
149 | __attribute__((noinline)); | |
150 | void side_ptrace_hook(const struct side_event_state *event_state __attribute__((unused)), | |
151 | const struct side_arg_vec *side_arg_vec __attribute__((unused)), | |
152 | const struct side_arg_dynamic_struct *var_struct __attribute__((unused))) | |
153 | { | |
154 | } | |
155 | ||
74be90b7 | 156 | static |
bffe9ae3 | 157 | void _side_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec, uint64_t key) |
67337c4a MD |
158 | { |
159 | struct side_rcu_read_state rcu_read_state; | |
b2a84b9f | 160 | const struct side_event_state_0 *es0; |
67337c4a MD |
161 | const struct side_callback *side_cb; |
162 | uintptr_t enabled; | |
163 | ||
164 | if (side_unlikely(finalized)) | |
165 | return; | |
166 | if (side_unlikely(!initialized)) | |
167 | side_init(); | |
b2a84b9f MD |
168 | if (side_unlikely(event_state->version != 0)) |
169 | abort(); | |
49aea3ef | 170 | es0 = side_container_of(event_state, const struct side_event_state_0, parent); |
7269a8a3 | 171 | assert(!(es0->desc->flags & SIDE_EVENT_FLAG_VARIADIC)); |
b2a84b9f | 172 | enabled = __atomic_load_n(&es0->enabled, __ATOMIC_RELAXED); |
871851e7 MD |
173 | if (side_unlikely(enabled & SIDE_EVENT_ENABLED_SHARED_MASK)) { |
174 | if ((enabled & SIDE_EVENT_ENABLED_SHARED_USER_EVENT_MASK) && | |
bffe9ae3 | 175 | (key == SIDE_KEY_MATCH_ALL || key == SIDE_KEY_USER_EVENT)) { |
871851e7 MD |
176 | // TODO: call kernel write. |
177 | } | |
178 | if ((enabled & SIDE_EVENT_ENABLED_SHARED_PTRACE_MASK) && | |
bffe9ae3 | 179 | (key == SIDE_KEY_MATCH_ALL || key == SIDE_KEY_PTRACE)) |
871851e7 | 180 | side_ptrace_hook(event_state, side_arg_vec, NULL); |
67337c4a | 181 | } |
873bbf16 | 182 | side_rcu_read_begin(&event_rcu_gp, &rcu_read_state); |
92c377f9 | 183 | for (side_cb = side_rcu_dereference(es0->callbacks); side_cb->u.call != NULL; side_cb++) { |
bffe9ae3 | 184 | if (key != SIDE_KEY_MATCH_ALL && side_cb->key != SIDE_KEY_MATCH_ALL && side_cb->key != key) |
92c377f9 | 185 | continue; |
7269a8a3 | 186 | side_cb->u.call(es0->desc, side_arg_vec, side_cb->priv); |
92c377f9 | 187 | } |
873bbf16 | 188 | side_rcu_read_end(&event_rcu_gp, &rcu_read_state); |
67337c4a MD |
189 | } |
190 | ||
92c377f9 MD |
191 | void side_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec) |
192 | { | |
bffe9ae3 | 193 | _side_call(event_state, side_arg_vec, SIDE_KEY_MATCH_ALL); |
92c377f9 MD |
194 | } |
195 | ||
f0b01832 | 196 | void side_statedump_call(const struct side_event_state *event_state, const struct side_arg_vec *side_arg_vec) |
74be90b7 MD |
197 | { |
198 | _side_call(event_state, side_arg_vec, filter_key); | |
199 | } | |
200 | ||
201 | static | |
202 | void _side_call_variadic(const struct side_event_state *event_state, | |
67337c4a | 203 | const struct side_arg_vec *side_arg_vec, |
92c377f9 | 204 | const struct side_arg_dynamic_struct *var_struct, |
bffe9ae3 | 205 | uint64_t key) |
67337c4a MD |
206 | { |
207 | struct side_rcu_read_state rcu_read_state; | |
b2a84b9f | 208 | const struct side_event_state_0 *es0; |
67337c4a MD |
209 | const struct side_callback *side_cb; |
210 | uintptr_t enabled; | |
211 | ||
212 | if (side_unlikely(finalized)) | |
213 | return; | |
214 | if (side_unlikely(!initialized)) | |
215 | side_init(); | |
b2a84b9f MD |
216 | if (side_unlikely(event_state->version != 0)) |
217 | abort(); | |
49aea3ef | 218 | es0 = side_container_of(event_state, const struct side_event_state_0, parent); |
7269a8a3 | 219 | assert(es0->desc->flags & SIDE_EVENT_FLAG_VARIADIC); |
b2a84b9f | 220 | enabled = __atomic_load_n(&es0->enabled, __ATOMIC_RELAXED); |
871851e7 MD |
221 | if (side_unlikely(enabled & SIDE_EVENT_ENABLED_SHARED_MASK)) { |
222 | if ((enabled & SIDE_EVENT_ENABLED_SHARED_USER_EVENT_MASK) && | |
bffe9ae3 | 223 | (key == SIDE_KEY_MATCH_ALL || key == SIDE_KEY_USER_EVENT)) { |
871851e7 MD |
224 | // TODO: call kernel write. |
225 | } | |
226 | if ((enabled & SIDE_EVENT_ENABLED_SHARED_PTRACE_MASK) && | |
bffe9ae3 | 227 | (key == SIDE_KEY_MATCH_ALL || key == SIDE_KEY_PTRACE)) |
871851e7 | 228 | side_ptrace_hook(event_state, side_arg_vec, var_struct); |
67337c4a | 229 | } |
873bbf16 | 230 | side_rcu_read_begin(&event_rcu_gp, &rcu_read_state); |
92c377f9 | 231 | for (side_cb = side_rcu_dereference(es0->callbacks); side_cb->u.call_variadic != NULL; side_cb++) { |
bffe9ae3 | 232 | if (key != SIDE_KEY_MATCH_ALL && side_cb->key != SIDE_KEY_MATCH_ALL && side_cb->key != key) |
92c377f9 | 233 | continue; |
7269a8a3 | 234 | side_cb->u.call_variadic(es0->desc, side_arg_vec, var_struct, side_cb->priv); |
92c377f9 | 235 | } |
873bbf16 | 236 | side_rcu_read_end(&event_rcu_gp, &rcu_read_state); |
67337c4a MD |
237 | } |
238 | ||
92c377f9 MD |
239 | void side_call_variadic(const struct side_event_state *event_state, |
240 | const struct side_arg_vec *side_arg_vec, | |
241 | const struct side_arg_dynamic_struct *var_struct) | |
242 | { | |
bffe9ae3 | 243 | _side_call_variadic(event_state, side_arg_vec, var_struct, SIDE_KEY_MATCH_ALL); |
74be90b7 MD |
244 | } |
245 | ||
f0b01832 | 246 | void side_statedump_call_variadic(const struct side_event_state *event_state, |
74be90b7 MD |
247 | const struct side_arg_vec *side_arg_vec, |
248 | const struct side_arg_dynamic_struct *var_struct) | |
249 | { | |
250 | _side_call_variadic(event_state, side_arg_vec, var_struct, filter_key); | |
92c377f9 MD |
251 | } |
252 | ||
67337c4a MD |
253 | static |
254 | const struct side_callback *side_tracer_callback_lookup( | |
255 | const struct side_event_description *desc, | |
bffe9ae3 | 256 | void *call, void *priv, uint64_t key) |
67337c4a | 257 | { |
0b9e59d6 | 258 | struct side_event_state *event_state = side_ptr_get(desc->state); |
b2a84b9f | 259 | const struct side_event_state_0 *es0; |
67337c4a MD |
260 | const struct side_callback *cb; |
261 | ||
b2a84b9f MD |
262 | if (side_unlikely(event_state->version != 0)) |
263 | abort(); | |
49aea3ef | 264 | es0 = side_container_of(event_state, const struct side_event_state_0, parent); |
7269a8a3 | 265 | for (cb = es0->callbacks; cb->u.call != NULL; cb++) { |
92c377f9 | 266 | if ((void *) cb->u.call == call && cb->priv == priv && cb->key == key) |
67337c4a MD |
267 | return cb; |
268 | } | |
269 | return NULL; | |
270 | } | |
271 | ||
272 | static | |
273 | int _side_tracer_callback_register(struct side_event_description *desc, | |
bffe9ae3 | 274 | void *call, void *priv, uint64_t key) |
67337c4a | 275 | { |
0b9e59d6 | 276 | struct side_event_state *event_state; |
67337c4a | 277 | struct side_callback *old_cb, *new_cb; |
b2a84b9f | 278 | struct side_event_state_0 *es0; |
67337c4a MD |
279 | int ret = SIDE_ERROR_OK; |
280 | uint32_t old_nr_cb; | |
281 | ||
282 | if (!call) | |
283 | return SIDE_ERROR_INVAL; | |
284 | if (finalized) | |
285 | return SIDE_ERROR_EXITING; | |
286 | if (!initialized) | |
287 | side_init(); | |
873bbf16 | 288 | pthread_mutex_lock(&side_event_lock); |
0b9e59d6 | 289 | event_state = side_ptr_get(desc->state); |
b2a84b9f MD |
290 | if (side_unlikely(event_state->version != 0)) |
291 | abort(); | |
49aea3ef | 292 | es0 = side_container_of(event_state, struct side_event_state_0, parent); |
3cac1780 | 293 | old_nr_cb = es0->nr_callbacks; |
67337c4a MD |
294 | if (old_nr_cb == UINT32_MAX) { |
295 | ret = SIDE_ERROR_INVAL; | |
296 | goto unlock; | |
297 | } | |
298 | /* Reject duplicate (call, priv) tuples. */ | |
92c377f9 | 299 | if (side_tracer_callback_lookup(desc, call, priv, key)) { |
67337c4a MD |
300 | ret = SIDE_ERROR_EXIST; |
301 | goto unlock; | |
302 | } | |
7269a8a3 | 303 | old_cb = (struct side_callback *) es0->callbacks; |
67337c4a MD |
304 | /* old_nr_cb + 1 (new cb) + 1 (NULL) */ |
305 | new_cb = (struct side_callback *) calloc(old_nr_cb + 2, sizeof(struct side_callback)); | |
306 | if (!new_cb) { | |
307 | ret = SIDE_ERROR_NOMEM; | |
308 | goto unlock; | |
309 | } | |
310 | memcpy(new_cb, old_cb, old_nr_cb); | |
311 | if (desc->flags & SIDE_EVENT_FLAG_VARIADIC) | |
312 | new_cb[old_nr_cb].u.call_variadic = | |
313 | (side_tracer_callback_variadic_func) call; | |
314 | else | |
315 | new_cb[old_nr_cb].u.call = | |
316 | (side_tracer_callback_func) call; | |
317 | new_cb[old_nr_cb].priv = priv; | |
92c377f9 | 318 | new_cb[old_nr_cb].key = key; |
f60d8121 | 319 | /* High order bits are already zeroed. */ |
7269a8a3 | 320 | side_rcu_assign_pointer(es0->callbacks, new_cb); |
873bbf16 | 321 | side_rcu_wait_grace_period(&event_rcu_gp); |
67337c4a MD |
322 | if (old_nr_cb) |
323 | free(old_cb); | |
3cac1780 | 324 | es0->nr_callbacks++; |
67337c4a MD |
325 | /* Increment concurrently with kernel setting the top bits. */ |
326 | if (!old_nr_cb) | |
b2a84b9f | 327 | (void) __atomic_add_fetch(&es0->enabled, 1, __ATOMIC_RELAXED); |
67337c4a | 328 | unlock: |
873bbf16 | 329 | pthread_mutex_unlock(&side_event_lock); |
67337c4a MD |
330 | return ret; |
331 | } | |
332 | ||
333 | int side_tracer_callback_register(struct side_event_description *desc, | |
334 | side_tracer_callback_func call, | |
bffe9ae3 | 335 | void *priv, uint64_t key) |
67337c4a MD |
336 | { |
337 | if (desc->flags & SIDE_EVENT_FLAG_VARIADIC) | |
338 | return SIDE_ERROR_INVAL; | |
92c377f9 | 339 | return _side_tracer_callback_register(desc, (void *) call, priv, key); |
67337c4a MD |
340 | } |
341 | ||
342 | int side_tracer_callback_variadic_register(struct side_event_description *desc, | |
343 | side_tracer_callback_variadic_func call_variadic, | |
bffe9ae3 | 344 | void *priv, uint64_t key) |
67337c4a MD |
345 | { |
346 | if (!(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) | |
347 | return SIDE_ERROR_INVAL; | |
92c377f9 | 348 | return _side_tracer_callback_register(desc, (void *) call_variadic, priv, key); |
67337c4a MD |
349 | } |
350 | ||
351 | static int _side_tracer_callback_unregister(struct side_event_description *desc, | |
bffe9ae3 | 352 | void *call, void *priv, uint64_t key) |
67337c4a | 353 | { |
0b9e59d6 | 354 | struct side_event_state *event_state; |
67337c4a MD |
355 | struct side_callback *old_cb, *new_cb; |
356 | const struct side_callback *cb_pos; | |
b2a84b9f | 357 | struct side_event_state_0 *es0; |
67337c4a MD |
358 | uint32_t pos_idx; |
359 | int ret = SIDE_ERROR_OK; | |
360 | uint32_t old_nr_cb; | |
361 | ||
362 | if (!call) | |
363 | return SIDE_ERROR_INVAL; | |
364 | if (finalized) | |
365 | return SIDE_ERROR_EXITING; | |
366 | if (!initialized) | |
367 | side_init(); | |
873bbf16 | 368 | pthread_mutex_lock(&side_event_lock); |
0b9e59d6 | 369 | event_state = side_ptr_get(desc->state); |
b2a84b9f MD |
370 | if (side_unlikely(event_state->version != 0)) |
371 | abort(); | |
49aea3ef | 372 | es0 = side_container_of(event_state, struct side_event_state_0, parent); |
92c377f9 | 373 | cb_pos = side_tracer_callback_lookup(desc, call, priv, key); |
67337c4a MD |
374 | if (!cb_pos) { |
375 | ret = SIDE_ERROR_NOENT; | |
376 | goto unlock; | |
377 | } | |
3cac1780 | 378 | old_nr_cb = es0->nr_callbacks; |
7269a8a3 | 379 | old_cb = (struct side_callback *) es0->callbacks; |
67337c4a MD |
380 | if (old_nr_cb == 1) { |
381 | new_cb = (struct side_callback *) &side_empty_callback; | |
382 | } else { | |
7269a8a3 | 383 | pos_idx = cb_pos - es0->callbacks; |
67337c4a MD |
384 | /* Remove entry at pos_idx. */ |
385 | /* old_nr_cb - 1 (removed cb) + 1 (NULL) */ | |
386 | new_cb = (struct side_callback *) calloc(old_nr_cb, sizeof(struct side_callback)); | |
387 | if (!new_cb) { | |
388 | ret = SIDE_ERROR_NOMEM; | |
389 | goto unlock; | |
390 | } | |
391 | memcpy(new_cb, old_cb, pos_idx); | |
392 | memcpy(&new_cb[pos_idx], &old_cb[pos_idx + 1], old_nr_cb - pos_idx - 1); | |
393 | } | |
f60d8121 | 394 | /* High order bits are already zeroed. */ |
7269a8a3 | 395 | side_rcu_assign_pointer(es0->callbacks, new_cb); |
873bbf16 | 396 | side_rcu_wait_grace_period(&event_rcu_gp); |
67337c4a | 397 | free(old_cb); |
3cac1780 | 398 | es0->nr_callbacks--; |
67337c4a MD |
399 | /* Decrement concurrently with kernel setting the top bits. */ |
400 | if (old_nr_cb == 1) | |
b2a84b9f | 401 | (void) __atomic_add_fetch(&es0->enabled, -1, __ATOMIC_RELAXED); |
67337c4a | 402 | unlock: |
873bbf16 | 403 | pthread_mutex_unlock(&side_event_lock); |
67337c4a MD |
404 | return ret; |
405 | } | |
406 | ||
407 | int side_tracer_callback_unregister(struct side_event_description *desc, | |
408 | side_tracer_callback_func call, | |
bffe9ae3 | 409 | void *priv, uint64_t key) |
67337c4a MD |
410 | { |
411 | if (desc->flags & SIDE_EVENT_FLAG_VARIADIC) | |
412 | return SIDE_ERROR_INVAL; | |
92c377f9 | 413 | return _side_tracer_callback_unregister(desc, (void *) call, priv, key); |
67337c4a MD |
414 | } |
415 | ||
416 | int side_tracer_callback_variadic_unregister(struct side_event_description *desc, | |
417 | side_tracer_callback_variadic_func call_variadic, | |
bffe9ae3 | 418 | void *priv, uint64_t key) |
67337c4a MD |
419 | { |
420 | if (!(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) | |
421 | return SIDE_ERROR_INVAL; | |
92c377f9 | 422 | return _side_tracer_callback_unregister(desc, (void *) call_variadic, priv, key); |
67337c4a MD |
423 | } |
424 | ||
425 | struct side_events_register_handle *side_events_register(struct side_event_description **events, uint32_t nr_events) | |
426 | { | |
427 | struct side_events_register_handle *events_handle = NULL; | |
428 | struct side_tracer_handle *tracer_handle; | |
429 | ||
430 | if (finalized) | |
431 | return NULL; | |
432 | if (!initialized) | |
433 | side_init(); | |
434 | events_handle = (struct side_events_register_handle *) | |
435 | calloc(1, sizeof(struct side_events_register_handle)); | |
436 | if (!events_handle) | |
437 | return NULL; | |
438 | events_handle->events = events; | |
439 | events_handle->nr_events = nr_events; | |
440 | ||
873bbf16 | 441 | pthread_mutex_lock(&side_event_lock); |
67337c4a MD |
442 | side_list_insert_node_tail(&side_events_list, &events_handle->node); |
443 | side_list_for_each_entry(tracer_handle, &side_tracer_list, node) { | |
444 | tracer_handle->cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS, | |
445 | events, nr_events, tracer_handle->priv); | |
446 | } | |
873bbf16 | 447 | pthread_mutex_unlock(&side_event_lock); |
67337c4a MD |
448 | //TODO: call event batch register ioctl |
449 | return events_handle; | |
450 | } | |
451 | ||
452 | static | |
453 | void side_event_remove_callbacks(struct side_event_description *desc) | |
454 | { | |
0b9e59d6 | 455 | struct side_event_state *event_state = side_ptr_get(desc->state); |
b2a84b9f | 456 | struct side_event_state_0 *es0; |
67337c4a | 457 | struct side_callback *old_cb; |
3cac1780 | 458 | uint32_t nr_cb; |
67337c4a | 459 | |
b2a84b9f MD |
460 | if (side_unlikely(event_state->version != 0)) |
461 | abort(); | |
49aea3ef | 462 | es0 = side_container_of(event_state, struct side_event_state_0, parent); |
3cac1780 MD |
463 | nr_cb = es0->nr_callbacks; |
464 | if (!nr_cb) | |
465 | return; | |
7269a8a3 | 466 | old_cb = (struct side_callback *) es0->callbacks; |
b2a84b9f | 467 | (void) __atomic_add_fetch(&es0->enabled, -1, __ATOMIC_RELAXED); |
67337c4a MD |
468 | /* |
469 | * Setting the state back to 0 cb and empty callbacks out of | |
470 | * caution. This should not matter because instrumentation is | |
471 | * unreachable. | |
472 | */ | |
3cac1780 | 473 | es0->nr_callbacks = 0; |
7269a8a3 | 474 | side_rcu_assign_pointer(es0->callbacks, &side_empty_callback); |
67337c4a MD |
475 | /* |
476 | * No need to wait for grace period because instrumentation is | |
477 | * unreachable. | |
478 | */ | |
479 | free(old_cb); | |
480 | } | |
481 | ||
482 | /* | |
483 | * Unregister event handle. At this point, all side events in that | |
484 | * handle should be unreachable. | |
485 | */ | |
486 | void side_events_unregister(struct side_events_register_handle *events_handle) | |
487 | { | |
488 | struct side_tracer_handle *tracer_handle; | |
489 | uint32_t i; | |
490 | ||
491 | if (!events_handle) | |
492 | return; | |
493 | if (finalized) | |
494 | return; | |
495 | if (!initialized) | |
496 | side_init(); | |
873bbf16 | 497 | pthread_mutex_lock(&side_event_lock); |
67337c4a MD |
498 | side_list_remove_node(&events_handle->node); |
499 | side_list_for_each_entry(tracer_handle, &side_tracer_list, node) { | |
500 | tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS, | |
501 | events_handle->events, events_handle->nr_events, | |
502 | tracer_handle->priv); | |
503 | } | |
504 | for (i = 0; i < events_handle->nr_events; i++) { | |
505 | struct side_event_description *event = events_handle->events[i]; | |
506 | ||
507 | /* Skip NULL pointers */ | |
508 | if (!event) | |
509 | continue; | |
510 | side_event_remove_callbacks(event); | |
511 | } | |
873bbf16 | 512 | pthread_mutex_unlock(&side_event_lock); |
67337c4a MD |
513 | //TODO: call event batch unregister ioctl |
514 | free(events_handle); | |
515 | } | |
516 | ||
517 | struct side_tracer_handle *side_tracer_event_notification_register( | |
518 | void (*cb)(enum side_tracer_notification notif, | |
519 | struct side_event_description **events, uint32_t nr_events, void *priv), | |
520 | void *priv) | |
521 | { | |
522 | struct side_tracer_handle *tracer_handle; | |
523 | struct side_events_register_handle *events_handle; | |
524 | ||
525 | if (finalized) | |
526 | return NULL; | |
527 | if (!initialized) | |
528 | side_init(); | |
529 | tracer_handle = (struct side_tracer_handle *) | |
530 | calloc(1, sizeof(struct side_tracer_handle)); | |
531 | if (!tracer_handle) | |
532 | return NULL; | |
873bbf16 | 533 | pthread_mutex_lock(&side_event_lock); |
67337c4a MD |
534 | tracer_handle->cb = cb; |
535 | tracer_handle->priv = priv; | |
536 | side_list_insert_node_tail(&side_tracer_list, &tracer_handle->node); | |
537 | side_list_for_each_entry(events_handle, &side_events_list, node) { | |
538 | cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS, | |
539 | events_handle->events, events_handle->nr_events, priv); | |
540 | } | |
873bbf16 | 541 | pthread_mutex_unlock(&side_event_lock); |
67337c4a MD |
542 | return tracer_handle; |
543 | } | |
544 | ||
545 | void side_tracer_event_notification_unregister(struct side_tracer_handle *tracer_handle) | |
546 | { | |
547 | struct side_events_register_handle *events_handle; | |
548 | ||
549 | if (finalized) | |
550 | return; | |
551 | if (!initialized) | |
552 | side_init(); | |
873bbf16 | 553 | pthread_mutex_lock(&side_event_lock); |
67337c4a MD |
554 | side_list_for_each_entry(events_handle, &side_events_list, node) { |
555 | tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS, | |
556 | events_handle->events, events_handle->nr_events, | |
557 | tracer_handle->priv); | |
558 | } | |
559 | side_list_remove_node(&tracer_handle->node); | |
873bbf16 | 560 | pthread_mutex_unlock(&side_event_lock); |
be787080 | 561 | free(tracer_handle); |
67337c4a MD |
562 | } |
563 | ||
bffe9ae3 MD |
564 | /* Called with side_statedump_lock held. */ |
565 | static | |
566 | void queue_statedump_pending(struct side_statedump_request_handle *handle, uint64_t key) | |
567 | { | |
568 | struct side_statedump_notification *notif; | |
569 | ||
570 | notif = (struct side_statedump_notification *) calloc(1, sizeof(struct side_statedump_notification)); | |
571 | if (!notif) | |
572 | abort(); | |
573 | notif->key = key; | |
574 | side_list_insert_node_tail(&handle->notification_queue, ¬if->node); | |
a125f217 MD |
575 | if (handle->mode == SIDE_STATEDUMP_MODE_AGENT_THREAD) |
576 | (void)__atomic_or_fetch(&statedump_agent_thread.state, AGENT_THREAD_STATE_HANDLE_REQUEST, __ATOMIC_SEQ_CST); | |
bffe9ae3 MD |
577 | } |
578 | ||
579 | /* Called with side_statedump_lock held. */ | |
580 | static | |
581 | void unqueue_statedump_pending(struct side_statedump_request_handle *handle, uint64_t key) | |
582 | { | |
583 | struct side_statedump_notification *notif, *tmp; | |
584 | ||
585 | side_list_for_each_entry_safe(notif, tmp, &handle->notification_queue, node) { | |
586 | if (key == SIDE_KEY_MATCH_ALL || key == notif->key) { | |
587 | side_list_remove_node(¬if->node); | |
588 | free(notif); | |
589 | } | |
590 | } | |
591 | } | |
592 | ||
a125f217 MD |
593 | static |
594 | void side_statedump_run(struct side_statedump_request_handle *handle, | |
595 | struct side_statedump_notification *notif) | |
596 | { | |
597 | /* Invoke the state dump callback specifically for the tracer key. */ | |
598 | filter_key = notif->key; | |
599 | side_statedump_event_call(side_statedump_begin, | |
600 | side_arg_list(side_arg_string(handle->name))); | |
601 | handle->cb(); | |
602 | side_statedump_event_call(side_statedump_end, | |
603 | side_arg_list(side_arg_string(handle->name))); | |
604 | filter_key = SIDE_KEY_MATCH_ALL; | |
605 | } | |
606 | ||
607 | static | |
608 | void _side_statedump_run_pending_requests(struct side_statedump_request_handle *handle) | |
609 | { | |
610 | struct side_statedump_notification *notif, *tmp; | |
611 | DEFINE_SIDE_LIST_HEAD(tmp_head); | |
612 | ||
613 | pthread_mutex_lock(&side_statedump_lock); | |
614 | side_list_splice(&handle->notification_queue, &tmp_head); | |
615 | side_list_head_init(&handle->notification_queue); | |
616 | pthread_mutex_unlock(&side_statedump_lock); | |
617 | ||
618 | /* We are now sole owner of the tmp_head list. */ | |
619 | side_list_for_each_entry(notif, &tmp_head, node) | |
620 | side_statedump_run(handle, notif); | |
621 | side_list_for_each_entry_safe(notif, tmp, &tmp_head, node) | |
622 | free(notif); | |
623 | } | |
624 | ||
625 | static | |
626 | void *statedump_agent_func(void *arg __attribute__((unused))) | |
627 | { | |
628 | for (;;) { | |
629 | struct side_statedump_request_handle *handle; | |
630 | struct side_rcu_read_state rcu_read_state; | |
631 | enum agent_thread_state state; | |
632 | ||
633 | /* TODO: futex-based wakeup. */ | |
634 | state = __atomic_load_n(&statedump_agent_thread.state, __ATOMIC_SEQ_CST); | |
635 | if (state == AGENT_THREAD_STATE_BLOCKED) { | |
636 | sleep(1); | |
637 | continue; | |
638 | } | |
639 | if (state & AGENT_THREAD_STATE_EXIT) | |
640 | break; | |
641 | (void)__atomic_and_fetch(&statedump_agent_thread.state, ~AGENT_THREAD_STATE_HANDLE_REQUEST, __ATOMIC_SEQ_CST); | |
642 | side_rcu_read_begin(&statedump_rcu_gp, &rcu_read_state); | |
643 | side_list_for_each_entry_rcu(handle, &side_statedump_list, node) | |
644 | _side_statedump_run_pending_requests(handle); | |
645 | side_rcu_read_end(&statedump_rcu_gp, &rcu_read_state); | |
646 | } | |
647 | return NULL; | |
648 | } | |
649 | ||
650 | static | |
651 | void statedump_agent_thread_get(void) | |
652 | { | |
653 | int ret; | |
654 | ||
655 | if (statedump_agent_thread.ref++) | |
656 | return; | |
657 | statedump_agent_thread.state = AGENT_THREAD_STATE_BLOCKED; | |
658 | ret = pthread_create(&statedump_agent_thread.id, NULL, | |
659 | statedump_agent_func, NULL); | |
660 | if (ret) { | |
661 | abort(); | |
662 | } | |
663 | } | |
664 | ||
665 | static | |
666 | void statedump_agent_thread_put(void) | |
667 | { | |
668 | int ret; | |
669 | void *retval; | |
670 | ||
671 | if (--statedump_agent_thread.ref) | |
672 | return; | |
673 | (void)__atomic_or_fetch(&statedump_agent_thread.state, AGENT_THREAD_STATE_EXIT, __ATOMIC_SEQ_CST); | |
674 | ret = pthread_join(statedump_agent_thread.id, &retval); | |
675 | if (ret) { | |
676 | abort(); | |
677 | } | |
678 | statedump_agent_thread.state = AGENT_THREAD_STATE_BLOCKED; | |
679 | } | |
680 | ||
bffe9ae3 MD |
681 | struct side_statedump_request_handle * |
682 | side_statedump_request_notification_register(const char *state_name, | |
683 | void (*statedump_cb)(void), | |
684 | enum side_statedump_mode mode) | |
f0b01832 MD |
685 | { |
686 | struct side_statedump_request_handle *handle; | |
bffe9ae3 | 687 | char *name; |
f0b01832 MD |
688 | |
689 | if (finalized) | |
690 | return NULL; | |
691 | if (!initialized) | |
692 | side_init(); | |
693 | /* | |
694 | * The statedump request notification should not be registered | |
695 | * from a notification callback. | |
696 | */ | |
bffe9ae3 | 697 | assert(!filter_key); |
f0b01832 MD |
698 | handle = (struct side_statedump_request_handle *) |
699 | calloc(1, sizeof(struct side_statedump_request_handle)); | |
700 | if (!handle) | |
701 | return NULL; | |
bffe9ae3 MD |
702 | name = strdup(state_name); |
703 | if (!name) | |
704 | goto name_nomem; | |
f0b01832 | 705 | handle->cb = statedump_cb; |
bffe9ae3 MD |
706 | handle->name = name; |
707 | handle->mode = mode; | |
708 | side_list_head_init(&handle->notification_queue); | |
873bbf16 MD |
709 | |
710 | pthread_mutex_lock(&side_statedump_lock); | |
a125f217 MD |
711 | if (mode == SIDE_STATEDUMP_MODE_AGENT_THREAD) |
712 | statedump_agent_thread_get(); | |
873bbf16 | 713 | side_list_insert_node_tail_rcu(&side_statedump_list, &handle->node); |
bffe9ae3 MD |
714 | /* Queue statedump pending for all tracers. */ |
715 | queue_statedump_pending(handle, SIDE_KEY_MATCH_ALL); | |
873bbf16 MD |
716 | pthread_mutex_unlock(&side_statedump_lock); |
717 | ||
a125f217 MD |
718 | if (mode == SIDE_STATEDUMP_MODE_AGENT_THREAD) { |
719 | for (;;) { | |
720 | bool is_empty; | |
721 | ||
722 | /* TODO futex based wakeup. */ | |
723 | pthread_mutex_lock(&side_statedump_lock); | |
724 | is_empty = side_list_empty(&handle->notification_queue); | |
725 | pthread_mutex_unlock(&side_statedump_lock); | |
726 | if (is_empty) | |
727 | break; | |
728 | sleep(1); | |
729 | } | |
730 | } | |
731 | ||
f0b01832 | 732 | return handle; |
bffe9ae3 MD |
733 | |
734 | name_nomem: | |
735 | free(handle); | |
736 | return NULL; | |
f0b01832 MD |
737 | } |
738 | ||
739 | void side_statedump_request_notification_unregister(struct side_statedump_request_handle *handle) | |
740 | { | |
741 | if (finalized) | |
742 | return; | |
743 | if (!initialized) | |
744 | side_init(); | |
bffe9ae3 | 745 | assert(!filter_key); |
873bbf16 MD |
746 | |
747 | pthread_mutex_lock(&side_statedump_lock); | |
bffe9ae3 | 748 | unqueue_statedump_pending(handle, SIDE_KEY_MATCH_ALL); |
873bbf16 | 749 | side_list_remove_node_rcu(&handle->node); |
a125f217 MD |
750 | if (handle->mode == SIDE_STATEDUMP_MODE_AGENT_THREAD) |
751 | statedump_agent_thread_put(); | |
873bbf16 MD |
752 | pthread_mutex_unlock(&side_statedump_lock); |
753 | ||
754 | side_rcu_wait_grace_period(&statedump_rcu_gp); | |
bffe9ae3 | 755 | free(handle->name); |
f0b01832 MD |
756 | free(handle); |
757 | } | |
758 | ||
bffe9ae3 MD |
759 | /* Returns true if the handle has pending statedump requests. */ |
760 | bool side_statedump_poll_pending_requests(struct side_statedump_request_handle *handle) | |
f0b01832 | 761 | { |
bffe9ae3 MD |
762 | bool ret; |
763 | ||
764 | if (handle->mode != SIDE_STATEDUMP_MODE_POLLING) | |
765 | return false; | |
766 | pthread_mutex_lock(&side_statedump_lock); | |
767 | ret = !side_list_empty(&handle->notification_queue); | |
768 | pthread_mutex_unlock(&side_statedump_lock); | |
769 | return ret; | |
770 | } | |
f0b01832 | 771 | |
bffe9ae3 MD |
772 | /* |
773 | * Only polling mode state dump handles allow application to explicitly handle the | |
774 | * pending requests. | |
775 | */ | |
776 | int side_statedump_run_pending_requests(struct side_statedump_request_handle *handle) | |
777 | { | |
778 | if (handle->mode != SIDE_STATEDUMP_MODE_POLLING) | |
779 | return SIDE_ERROR_INVAL; | |
780 | _side_statedump_run_pending_requests(handle); | |
781 | return SIDE_ERROR_OK; | |
782 | } | |
783 | ||
784 | /* | |
785 | * Request a state dump for tracer callbacks identified with "key". | |
786 | */ | |
787 | int side_tracer_statedump_request(uint64_t key) | |
788 | { | |
789 | struct side_statedump_request_handle *handle; | |
790 | ||
791 | if (key == SIDE_KEY_MATCH_ALL) | |
792 | return SIDE_ERROR_INVAL; | |
793 | pthread_mutex_lock(&side_statedump_lock); | |
794 | side_list_for_each_entry(handle, &side_statedump_list, node) | |
795 | queue_statedump_pending(handle, key); | |
796 | pthread_mutex_lock(&side_statedump_lock); | |
797 | return SIDE_ERROR_OK; | |
798 | } | |
799 | ||
800 | /* | |
801 | * Cancel a statedump request. | |
802 | */ | |
803 | int side_tracer_statedump_request_cancel(uint64_t key) | |
804 | { | |
805 | struct side_statedump_request_handle *handle; | |
806 | ||
807 | if (key == SIDE_KEY_MATCH_ALL) | |
808 | return SIDE_ERROR_INVAL; | |
809 | pthread_mutex_lock(&side_statedump_lock); | |
810 | side_list_for_each_entry(handle, &side_statedump_list, node) | |
811 | unqueue_statedump_pending(handle, key); | |
812 | pthread_mutex_lock(&side_statedump_lock); | |
813 | return SIDE_ERROR_OK; | |
814 | } | |
815 | ||
816 | /* | |
817 | * Tracer keys are represented on 64-bit. Return SIDE_ERROR_NOMEM on | |
818 | * overflow (which should never happen in practice). | |
819 | */ | |
820 | int side_tracer_request_key(uint64_t *key) | |
821 | { | |
822 | int ret = SIDE_ERROR_OK; | |
823 | ||
824 | pthread_mutex_lock(&side_key_lock); | |
825 | if (side_key_next == 0) { | |
826 | ret = SIDE_ERROR_NOMEM; | |
827 | goto end; | |
828 | } | |
829 | *key = side_key_next++; | |
830 | end: | |
831 | pthread_mutex_unlock(&side_key_lock); | |
832 | return ret; | |
f0b01832 MD |
833 | } |
834 | ||
67337c4a MD |
835 | void side_init(void) |
836 | { | |
837 | if (initialized) | |
838 | return; | |
873bbf16 MD |
839 | side_rcu_gp_init(&event_rcu_gp); |
840 | side_rcu_gp_init(&statedump_rcu_gp); | |
67337c4a MD |
841 | initialized = true; |
842 | } | |
843 | ||
844 | /* | |
845 | * side_exit() is executed from a library destructor. It can be called | |
846 | * explicitly at application exit as well. Concurrent side API use is | |
847 | * not expected at that point. | |
848 | */ | |
849 | void side_exit(void) | |
850 | { | |
851 | struct side_events_register_handle *handle, *tmp; | |
852 | ||
853 | if (finalized) | |
854 | return; | |
855 | side_list_for_each_entry_safe(handle, tmp, &side_events_list, node) | |
856 | side_events_unregister(handle); | |
873bbf16 MD |
857 | side_rcu_gp_exit(&event_rcu_gp); |
858 | side_rcu_gp_exit(&statedump_rcu_gp); | |
67337c4a MD |
859 | finalized = true; |
860 | } |