Commit | Line | Data |
---|---|---|
8020ceb5 | 1 | /* |
e92f3e28 | 2 | * lttng-context.c |
8020ceb5 | 3 | * |
8173ec7c | 4 | * LTTng UST trace/channel/event context management. |
8020ceb5 | 5 | * |
e92f3e28 MD |
6 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; only | |
11 | * version 2.1 of the License. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
8020ceb5 MD |
21 | */ |
22 | ||
3fbec7dc | 23 | #define _LGPL_SOURCE |
4318ae1b MD |
24 | #include <lttng/ust-events.h> |
25 | #include <lttng/ust-tracer.h> | |
53569322 MD |
26 | #include <lttng/ust-context-provider.h> |
27 | #include <urcu-pointer.h> | |
a0a3bef9 | 28 | #include <usterr-signal-safe.h> |
35897f8b | 29 | #include <helper.h> |
b4051ad8 | 30 | #include <stddef.h> |
8d8a24c8 | 31 | #include <string.h> |
8173ec7c MD |
32 | #include <assert.h> |
33 | ||
77aa5901 MD |
34 | /* |
35 | * The filter implementation requires that two consecutive "get" for the | |
36 | * same context performed by the same thread return the same result. | |
37 | */ | |
38 | ||
8173ec7c MD |
39 | int lttng_find_context(struct lttng_ctx *ctx, const char *name) |
40 | { | |
41 | unsigned int i; | |
53569322 | 42 | const char *subname; |
8173ec7c | 43 | |
53569322 MD |
44 | if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) { |
45 | subname = name + strlen("$ctx."); | |
46 | } else { | |
47 | subname = name; | |
48 | } | |
8173ec7c MD |
49 | for (i = 0; i < ctx->nr_fields; i++) { |
50 | /* Skip allocated (but non-initialized) contexts */ | |
51 | if (!ctx->fields[i].event_field.name) | |
52 | continue; | |
53569322 | 53 | if (!strcmp(ctx->fields[i].event_field.name, subname)) |
8173ec7c MD |
54 | return 1; |
55 | } | |
56 | return 0; | |
57 | } | |
8020ceb5 | 58 | |
77aa5901 MD |
59 | int lttng_get_context_index(struct lttng_ctx *ctx, const char *name) |
60 | { | |
61 | unsigned int i; | |
53569322 | 62 | const char *subname; |
77aa5901 MD |
63 | |
64 | if (!ctx) | |
65 | return -1; | |
53569322 MD |
66 | if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) { |
67 | subname = name + strlen("$ctx."); | |
68 | } else { | |
69 | subname = name; | |
70 | } | |
77aa5901 MD |
71 | for (i = 0; i < ctx->nr_fields; i++) { |
72 | /* Skip allocated (but non-initialized) contexts */ | |
73 | if (!ctx->fields[i].event_field.name) | |
74 | continue; | |
53569322 | 75 | if (!strcmp(ctx->fields[i].event_field.name, subname)) |
77aa5901 MD |
76 | return i; |
77 | } | |
78 | return -1; | |
79 | } | |
80 | ||
53569322 MD |
81 | static int lttng_find_context_provider(struct lttng_ctx *ctx, const char *name) |
82 | { | |
83 | unsigned int i; | |
84 | ||
85 | for (i = 0; i < ctx->nr_fields; i++) { | |
86 | /* Skip allocated (but non-initialized) contexts */ | |
87 | if (!ctx->fields[i].event_field.name) | |
88 | continue; | |
89 | if (!strncmp(ctx->fields[i].event_field.name, name, | |
90 | strlen(name))) | |
91 | return 1; | |
92 | } | |
93 | return 0; | |
94 | } | |
95 | ||
a0a748b8 MD |
96 | /* |
97 | * Note: as we append context information, the pointer location may change. | |
98 | */ | |
8020ceb5 MD |
99 | struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p) |
100 | { | |
101 | struct lttng_ctx_field *field; | |
102 | struct lttng_ctx *ctx; | |
103 | ||
104 | if (!*ctx_p) { | |
8d8a24c8 | 105 | *ctx_p = zmalloc(sizeof(struct lttng_ctx)); |
8020ceb5 MD |
106 | if (!*ctx_p) |
107 | return NULL; | |
b2cc986a | 108 | (*ctx_p)->largest_align = 1; |
8020ceb5 MD |
109 | } |
110 | ctx = *ctx_p; | |
111 | if (ctx->nr_fields + 1 > ctx->allocated_fields) { | |
112 | struct lttng_ctx_field *new_fields; | |
113 | ||
114 | ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields); | |
8d8a24c8 | 115 | new_fields = zmalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field)); |
8020ceb5 MD |
116 | if (!new_fields) |
117 | return NULL; | |
118 | if (ctx->fields) | |
119 | memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields); | |
8d8a24c8 | 120 | free(ctx->fields); |
8020ceb5 MD |
121 | ctx->fields = new_fields; |
122 | } | |
123 | field = &ctx->fields[ctx->nr_fields]; | |
124 | ctx->nr_fields++; | |
125 | return field; | |
126 | } | |
8020ceb5 | 127 | |
53569322 MD |
128 | int lttng_context_add_rcu(struct lttng_ctx **ctx_p, |
129 | const struct lttng_ctx_field *f) | |
130 | { | |
131 | struct lttng_ctx *old_ctx = *ctx_p, *new_ctx = NULL; | |
132 | struct lttng_ctx_field *new_fields = NULL; | |
133 | struct lttng_ctx_field *nf; | |
134 | ||
135 | if (old_ctx) { | |
136 | new_ctx = zmalloc(sizeof(struct lttng_ctx)); | |
137 | if (!new_ctx) | |
138 | return -ENOMEM; | |
139 | *new_ctx = *old_ctx; | |
140 | new_fields = zmalloc(new_ctx->allocated_fields | |
141 | * sizeof(struct lttng_ctx_field)); | |
142 | if (!new_fields) { | |
143 | free(new_ctx); | |
144 | return -ENOMEM; | |
145 | } | |
146 | memcpy(new_fields, old_ctx->fields, | |
147 | sizeof(*old_ctx->fields) * old_ctx->nr_fields); | |
148 | new_ctx->fields = new_fields; | |
149 | } | |
150 | nf = lttng_append_context(&new_ctx); | |
151 | if (!nf) { | |
152 | free(new_fields); | |
153 | free(new_ctx); | |
154 | return -ENOMEM; | |
155 | } | |
156 | *nf = *f; | |
157 | lttng_context_update(new_ctx); | |
158 | rcu_assign_pointer(*ctx_p, new_ctx); | |
159 | synchronize_trace(); | |
160 | if (old_ctx) { | |
161 | free(old_ctx->fields); | |
162 | free(old_ctx); | |
163 | } | |
164 | return 0; | |
165 | } | |
166 | ||
b2cc986a MD |
167 | /* |
168 | * lttng_context_update() should be called at least once between context | |
169 | * modification and trace start. | |
170 | */ | |
171 | void lttng_context_update(struct lttng_ctx *ctx) | |
172 | { | |
173 | int i; | |
174 | size_t largest_align = 8; /* in bits */ | |
175 | ||
176 | for (i = 0; i < ctx->nr_fields; i++) { | |
177 | struct lttng_type *type; | |
178 | size_t field_align = 8; | |
179 | ||
180 | type = &ctx->fields[i].event_field.type; | |
181 | switch (type->atype) { | |
182 | case atype_integer: | |
183 | field_align = type->u.basic.integer.alignment; | |
184 | break; | |
185 | case atype_array: | |
186 | { | |
187 | struct lttng_basic_type *btype; | |
188 | ||
189 | btype = &type->u.array.elem_type; | |
190 | switch (btype->atype) { | |
191 | case atype_integer: | |
192 | field_align = btype->u.basic.integer.alignment; | |
193 | break; | |
194 | case atype_string: | |
195 | break; | |
196 | ||
197 | case atype_array: | |
198 | case atype_sequence: | |
199 | default: | |
200 | WARN_ON_ONCE(1); | |
201 | break; | |
202 | } | |
203 | break; | |
204 | } | |
205 | case atype_sequence: | |
206 | { | |
207 | struct lttng_basic_type *btype; | |
208 | ||
209 | btype = &type->u.sequence.length_type; | |
210 | switch (btype->atype) { | |
211 | case atype_integer: | |
212 | field_align = btype->u.basic.integer.alignment; | |
213 | break; | |
214 | ||
215 | case atype_string: | |
216 | case atype_array: | |
217 | case atype_sequence: | |
218 | default: | |
219 | WARN_ON_ONCE(1); | |
220 | break; | |
221 | } | |
222 | ||
223 | btype = &type->u.sequence.elem_type; | |
224 | switch (btype->atype) { | |
225 | case atype_integer: | |
226 | field_align = max_t(size_t, | |
227 | field_align, | |
228 | btype->u.basic.integer.alignment); | |
229 | break; | |
230 | ||
231 | case atype_string: | |
232 | break; | |
233 | ||
234 | case atype_array: | |
235 | case atype_sequence: | |
236 | default: | |
237 | WARN_ON_ONCE(1); | |
238 | break; | |
239 | } | |
240 | break; | |
241 | } | |
242 | case atype_string: | |
243 | break; | |
53569322 MD |
244 | case atype_dynamic: |
245 | break; | |
b2cc986a MD |
246 | case atype_enum: |
247 | default: | |
248 | WARN_ON_ONCE(1); | |
249 | break; | |
250 | } | |
251 | largest_align = max_t(size_t, largest_align, field_align); | |
252 | } | |
253 | ctx->largest_align = largest_align >> 3; /* bits to bytes */ | |
254 | } | |
255 | ||
b13d13b1 MD |
256 | /* |
257 | * Remove last context field. | |
258 | */ | |
8020ceb5 MD |
259 | void lttng_remove_context_field(struct lttng_ctx **ctx_p, |
260 | struct lttng_ctx_field *field) | |
261 | { | |
262 | struct lttng_ctx *ctx; | |
263 | ||
264 | ctx = *ctx_p; | |
265 | ctx->nr_fields--; | |
8173ec7c | 266 | assert(&ctx->fields[ctx->nr_fields] == field); |
53569322 | 267 | assert(field->field_name == NULL); |
8020ceb5 MD |
268 | memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field)); |
269 | } | |
8020ceb5 MD |
270 | |
271 | void lttng_destroy_context(struct lttng_ctx *ctx) | |
272 | { | |
273 | int i; | |
274 | ||
275 | if (!ctx) | |
276 | return; | |
277 | for (i = 0; i < ctx->nr_fields; i++) { | |
278 | if (ctx->fields[i].destroy) | |
279 | ctx->fields[i].destroy(&ctx->fields[i]); | |
53569322 | 280 | free(ctx->fields[i].field_name); |
8020ceb5 | 281 | } |
8d8a24c8 MD |
282 | free(ctx->fields); |
283 | free(ctx); | |
8020ceb5 | 284 | } |
a0a3bef9 | 285 | |
53569322 MD |
286 | /* |
287 | * Can be safely performed concurrently with tracing using the struct | |
288 | * lttng_ctx. Using RCU update. Needs to match RCU read-side handling of | |
289 | * contexts. | |
290 | * | |
291 | * This does not allow adding, removing, or changing typing of the | |
292 | * contexts, since this needs to stay invariant for metadata. However, | |
293 | * it allows updating the handlers associated with all contexts matching | |
294 | * a provider (by name) while tracing is using it, in a way that ensures | |
295 | * a single RCU read-side critical section see either all old, or all | |
296 | * new handlers. | |
297 | */ | |
298 | int lttng_ust_context_set_provider_rcu(struct lttng_ctx **_ctx, | |
299 | const char *name, | |
300 | size_t (*get_size)(struct lttng_ctx_field *field, size_t offset), | |
301 | void (*record)(struct lttng_ctx_field *field, | |
302 | struct lttng_ust_lib_ring_buffer_ctx *ctx, | |
303 | struct lttng_channel *chan), | |
304 | void (*get_value)(struct lttng_ctx_field *field, | |
305 | struct lttng_ctx_value *value)) | |
306 | { | |
307 | int i, ret; | |
308 | struct lttng_ctx *ctx = *_ctx, *new_ctx; | |
309 | struct lttng_ctx_field *new_fields; | |
310 | ||
311 | if (!ctx || !lttng_find_context_provider(ctx, name)) | |
312 | return 0; | |
313 | /* | |
314 | * We have at least one instance of context for the provider. | |
315 | */ | |
316 | new_ctx = zmalloc(sizeof(*new_ctx)); | |
317 | if (!new_ctx) | |
318 | return -ENOMEM; | |
319 | *new_ctx = *ctx; | |
320 | new_fields = zmalloc(sizeof(*new_fields) * ctx->allocated_fields); | |
321 | if (!new_fields) { | |
322 | ret = -ENOMEM; | |
323 | goto field_error; | |
324 | } | |
325 | memcpy(new_fields, ctx->fields, | |
326 | sizeof(*new_fields) * ctx->allocated_fields); | |
327 | for (i = 0; i < ctx->nr_fields; i++) { | |
328 | if (strncmp(new_fields[i].event_field.name, | |
329 | name, strlen(name)) != 0) | |
330 | continue; | |
331 | new_fields[i].get_size = get_size; | |
332 | new_fields[i].record = record; | |
333 | new_fields[i].get_value = get_value; | |
334 | } | |
335 | new_ctx->fields = new_fields; | |
336 | rcu_assign_pointer(*_ctx, new_ctx); | |
337 | synchronize_trace(); | |
338 | free(ctx->fields); | |
339 | free(ctx); | |
340 | return 0; | |
341 | ||
342 | field_error: | |
343 | free(new_ctx); | |
344 | return ret; | |
345 | } | |
346 | ||
347 | int lttng_session_context_init(struct lttng_ctx **ctx) | |
a0a3bef9 MD |
348 | { |
349 | int ret; | |
350 | ||
53569322 | 351 | ret = lttng_add_pthread_id_to_ctx(ctx); |
a0a3bef9 MD |
352 | if (ret) { |
353 | WARN("Cannot add context lttng_add_pthread_id_to_ctx"); | |
53569322 | 354 | goto error; |
a0a3bef9 | 355 | } |
53569322 | 356 | ret = lttng_add_vtid_to_ctx(ctx); |
a0a3bef9 MD |
357 | if (ret) { |
358 | WARN("Cannot add context lttng_add_vtid_to_ctx"); | |
53569322 | 359 | goto error; |
a0a3bef9 | 360 | } |
53569322 | 361 | ret = lttng_add_vpid_to_ctx(ctx); |
a0a3bef9 MD |
362 | if (ret) { |
363 | WARN("Cannot add context lttng_add_vpid_to_ctx"); | |
53569322 | 364 | goto error; |
a0a3bef9 | 365 | } |
53569322 | 366 | ret = lttng_add_procname_to_ctx(ctx); |
a0a3bef9 MD |
367 | if (ret) { |
368 | WARN("Cannot add context lttng_add_procname_to_ctx"); | |
53569322 | 369 | goto error; |
a0a3bef9 | 370 | } |
53569322 | 371 | ret = lttng_add_cpu_id_to_ctx(ctx); |
c7ea8487 MD |
372 | if (ret) { |
373 | WARN("Cannot add context lttng_add_cpu_id_to_ctx"); | |
53569322 | 374 | goto error; |
c7ea8487 | 375 | } |
735bef47 MJ |
376 | ret = lttng_add_cgroup_ns_to_ctx(ctx); |
377 | if (ret) { | |
378 | WARN("Cannot add context lttng_add_cgroup_ns_to_ctx"); | |
379 | goto error; | |
380 | } | |
381 | ret = lttng_add_ipc_ns_to_ctx(ctx); | |
382 | if (ret) { | |
383 | WARN("Cannot add context lttng_add_ipc_ns_to_ctx"); | |
384 | goto error; | |
385 | } | |
386 | ret = lttng_add_mnt_ns_to_ctx(ctx); | |
387 | if (ret) { | |
388 | WARN("Cannot add context lttng_add_mnt_ns_to_ctx"); | |
389 | goto error; | |
390 | } | |
391 | ret = lttng_add_net_ns_to_ctx(ctx); | |
392 | if (ret) { | |
393 | WARN("Cannot add context lttng_add_net_ns_to_ctx"); | |
394 | goto error; | |
395 | } | |
396 | ret = lttng_add_pid_ns_to_ctx(ctx); | |
397 | if (ret) { | |
398 | WARN("Cannot add context lttng_add_pid_ns_to_ctx"); | |
399 | goto error; | |
400 | } | |
401 | ret = lttng_add_user_ns_to_ctx(ctx); | |
402 | if (ret) { | |
403 | WARN("Cannot add context lttng_add_user_ns_to_ctx"); | |
404 | goto error; | |
405 | } | |
406 | ret = lttng_add_uts_ns_to_ctx(ctx); | |
407 | if (ret) { | |
408 | WARN("Cannot add context lttng_add_uts_ns_to_ctx"); | |
409 | goto error; | |
410 | } | |
fca2f191 MJ |
411 | ret = lttng_add_vuid_to_ctx(ctx); |
412 | if (ret) { | |
413 | WARN("Cannot add context lttng_add_vuid_to_ctx"); | |
414 | goto error; | |
415 | } | |
416 | ret = lttng_add_veuid_to_ctx(ctx); | |
417 | if (ret) { | |
418 | WARN("Cannot add context lttng_add_veuid_to_ctx"); | |
419 | goto error; | |
420 | } | |
421 | ret = lttng_add_vsuid_to_ctx(ctx); | |
422 | if (ret) { | |
423 | WARN("Cannot add context lttng_add_vsuid_to_ctx"); | |
424 | goto error; | |
425 | } | |
426 | ret = lttng_add_vgid_to_ctx(ctx); | |
427 | if (ret) { | |
428 | WARN("Cannot add context lttng_add_vgid_to_ctx"); | |
429 | goto error; | |
430 | } | |
431 | ret = lttng_add_vegid_to_ctx(ctx); | |
432 | if (ret) { | |
433 | WARN("Cannot add context lttng_add_vegid_to_ctx"); | |
434 | goto error; | |
435 | } | |
436 | ret = lttng_add_vsgid_to_ctx(ctx); | |
437 | if (ret) { | |
438 | WARN("Cannot add context lttng_add_vsgid_to_ctx"); | |
439 | goto error; | |
440 | } | |
53569322 MD |
441 | lttng_context_update(*ctx); |
442 | return 0; | |
a0a3bef9 | 443 | |
53569322 MD |
444 | error: |
445 | lttng_destroy_context(*ctx); | |
446 | return ret; | |
a0a3bef9 | 447 | } |
4a1f7569 MD |
448 | |
449 | /* For backward compatibility. Leave those exported symbols in place. */ | |
450 | struct lttng_ctx *lttng_static_ctx; | |
451 | ||
452 | void lttng_context_init(void) | |
453 | { | |
454 | } | |
455 | ||
456 | void lttng_context_exit(void) | |
457 | { | |
458 | } |