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 | ||
e92f3e28 | 23 | |
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> |
8d8a24c8 | 30 | #include <string.h> |
8173ec7c MD |
31 | #include <assert.h> |
32 | ||
77aa5901 MD |
33 | /* |
34 | * The filter implementation requires that two consecutive "get" for the | |
35 | * same context performed by the same thread return the same result. | |
36 | */ | |
37 | ||
8173ec7c MD |
38 | int lttng_find_context(struct lttng_ctx *ctx, const char *name) |
39 | { | |
40 | unsigned int i; | |
53569322 | 41 | const char *subname; |
8173ec7c | 42 | |
53569322 MD |
43 | if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) { |
44 | subname = name + strlen("$ctx."); | |
45 | } else { | |
46 | subname = name; | |
47 | } | |
8173ec7c MD |
48 | for (i = 0; i < ctx->nr_fields; i++) { |
49 | /* Skip allocated (but non-initialized) contexts */ | |
50 | if (!ctx->fields[i].event_field.name) | |
51 | continue; | |
53569322 | 52 | if (!strcmp(ctx->fields[i].event_field.name, subname)) |
8173ec7c MD |
53 | return 1; |
54 | } | |
55 | return 0; | |
56 | } | |
8020ceb5 | 57 | |
53569322 MD |
58 | int lttng_context_is_app(const char *name) |
59 | { | |
60 | if (strncmp(name, "$app.", strlen("$app.")) != 0) { | |
61 | return 0; | |
62 | } | |
63 | return 1; | |
64 | } | |
65 | ||
77aa5901 MD |
66 | int lttng_get_context_index(struct lttng_ctx *ctx, const char *name) |
67 | { | |
68 | unsigned int i; | |
53569322 | 69 | const char *subname; |
77aa5901 MD |
70 | |
71 | if (!ctx) | |
72 | return -1; | |
53569322 MD |
73 | if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) { |
74 | subname = name + strlen("$ctx."); | |
75 | } else { | |
76 | subname = name; | |
77 | } | |
77aa5901 MD |
78 | for (i = 0; i < ctx->nr_fields; i++) { |
79 | /* Skip allocated (but non-initialized) contexts */ | |
80 | if (!ctx->fields[i].event_field.name) | |
81 | continue; | |
53569322 | 82 | if (!strcmp(ctx->fields[i].event_field.name, subname)) |
77aa5901 MD |
83 | return i; |
84 | } | |
85 | return -1; | |
86 | } | |
87 | ||
53569322 MD |
88 | static int lttng_find_context_provider(struct lttng_ctx *ctx, const char *name) |
89 | { | |
90 | unsigned int i; | |
91 | ||
92 | for (i = 0; i < ctx->nr_fields; i++) { | |
93 | /* Skip allocated (but non-initialized) contexts */ | |
94 | if (!ctx->fields[i].event_field.name) | |
95 | continue; | |
96 | if (!strncmp(ctx->fields[i].event_field.name, name, | |
97 | strlen(name))) | |
98 | return 1; | |
99 | } | |
100 | return 0; | |
101 | } | |
102 | ||
a0a748b8 MD |
103 | /* |
104 | * Note: as we append context information, the pointer location may change. | |
105 | */ | |
8020ceb5 MD |
106 | struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p) |
107 | { | |
108 | struct lttng_ctx_field *field; | |
109 | struct lttng_ctx *ctx; | |
110 | ||
111 | if (!*ctx_p) { | |
8d8a24c8 | 112 | *ctx_p = zmalloc(sizeof(struct lttng_ctx)); |
8020ceb5 MD |
113 | if (!*ctx_p) |
114 | return NULL; | |
b2cc986a | 115 | (*ctx_p)->largest_align = 1; |
8020ceb5 MD |
116 | } |
117 | ctx = *ctx_p; | |
118 | if (ctx->nr_fields + 1 > ctx->allocated_fields) { | |
119 | struct lttng_ctx_field *new_fields; | |
120 | ||
121 | ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields); | |
8d8a24c8 | 122 | new_fields = zmalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field)); |
8020ceb5 MD |
123 | if (!new_fields) |
124 | return NULL; | |
125 | if (ctx->fields) | |
126 | memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields); | |
8d8a24c8 | 127 | free(ctx->fields); |
8020ceb5 MD |
128 | ctx->fields = new_fields; |
129 | } | |
130 | field = &ctx->fields[ctx->nr_fields]; | |
131 | ctx->nr_fields++; | |
132 | return field; | |
133 | } | |
8020ceb5 | 134 | |
53569322 MD |
135 | int lttng_context_add_rcu(struct lttng_ctx **ctx_p, |
136 | const struct lttng_ctx_field *f) | |
137 | { | |
138 | struct lttng_ctx *old_ctx = *ctx_p, *new_ctx = NULL; | |
139 | struct lttng_ctx_field *new_fields = NULL; | |
140 | struct lttng_ctx_field *nf; | |
141 | ||
142 | if (old_ctx) { | |
143 | new_ctx = zmalloc(sizeof(struct lttng_ctx)); | |
144 | if (!new_ctx) | |
145 | return -ENOMEM; | |
146 | *new_ctx = *old_ctx; | |
147 | new_fields = zmalloc(new_ctx->allocated_fields | |
148 | * sizeof(struct lttng_ctx_field)); | |
149 | if (!new_fields) { | |
150 | free(new_ctx); | |
151 | return -ENOMEM; | |
152 | } | |
153 | memcpy(new_fields, old_ctx->fields, | |
154 | sizeof(*old_ctx->fields) * old_ctx->nr_fields); | |
155 | new_ctx->fields = new_fields; | |
156 | } | |
157 | nf = lttng_append_context(&new_ctx); | |
158 | if (!nf) { | |
159 | free(new_fields); | |
160 | free(new_ctx); | |
161 | return -ENOMEM; | |
162 | } | |
163 | *nf = *f; | |
164 | lttng_context_update(new_ctx); | |
165 | rcu_assign_pointer(*ctx_p, new_ctx); | |
166 | synchronize_trace(); | |
167 | if (old_ctx) { | |
168 | free(old_ctx->fields); | |
169 | free(old_ctx); | |
170 | } | |
171 | return 0; | |
172 | } | |
173 | ||
b2cc986a MD |
174 | /* |
175 | * lttng_context_update() should be called at least once between context | |
176 | * modification and trace start. | |
177 | */ | |
178 | void lttng_context_update(struct lttng_ctx *ctx) | |
179 | { | |
180 | int i; | |
181 | size_t largest_align = 8; /* in bits */ | |
182 | ||
183 | for (i = 0; i < ctx->nr_fields; i++) { | |
184 | struct lttng_type *type; | |
185 | size_t field_align = 8; | |
186 | ||
187 | type = &ctx->fields[i].event_field.type; | |
188 | switch (type->atype) { | |
189 | case atype_integer: | |
190 | field_align = type->u.basic.integer.alignment; | |
191 | break; | |
192 | case atype_array: | |
193 | { | |
194 | struct lttng_basic_type *btype; | |
195 | ||
196 | btype = &type->u.array.elem_type; | |
197 | switch (btype->atype) { | |
198 | case atype_integer: | |
199 | field_align = btype->u.basic.integer.alignment; | |
200 | break; | |
201 | case atype_string: | |
202 | break; | |
203 | ||
204 | case atype_array: | |
205 | case atype_sequence: | |
206 | default: | |
207 | WARN_ON_ONCE(1); | |
208 | break; | |
209 | } | |
210 | break; | |
211 | } | |
212 | case atype_sequence: | |
213 | { | |
214 | struct lttng_basic_type *btype; | |
215 | ||
216 | btype = &type->u.sequence.length_type; | |
217 | switch (btype->atype) { | |
218 | case atype_integer: | |
219 | field_align = btype->u.basic.integer.alignment; | |
220 | break; | |
221 | ||
222 | case atype_string: | |
223 | case atype_array: | |
224 | case atype_sequence: | |
225 | default: | |
226 | WARN_ON_ONCE(1); | |
227 | break; | |
228 | } | |
229 | ||
230 | btype = &type->u.sequence.elem_type; | |
231 | switch (btype->atype) { | |
232 | case atype_integer: | |
233 | field_align = max_t(size_t, | |
234 | field_align, | |
235 | btype->u.basic.integer.alignment); | |
236 | break; | |
237 | ||
238 | case atype_string: | |
239 | break; | |
240 | ||
241 | case atype_array: | |
242 | case atype_sequence: | |
243 | default: | |
244 | WARN_ON_ONCE(1); | |
245 | break; | |
246 | } | |
247 | break; | |
248 | } | |
249 | case atype_string: | |
250 | break; | |
53569322 MD |
251 | case atype_dynamic: |
252 | break; | |
b2cc986a MD |
253 | case atype_enum: |
254 | default: | |
255 | WARN_ON_ONCE(1); | |
256 | break; | |
257 | } | |
258 | largest_align = max_t(size_t, largest_align, field_align); | |
259 | } | |
260 | ctx->largest_align = largest_align >> 3; /* bits to bytes */ | |
261 | } | |
262 | ||
b13d13b1 MD |
263 | /* |
264 | * Remove last context field. | |
265 | */ | |
8020ceb5 MD |
266 | void lttng_remove_context_field(struct lttng_ctx **ctx_p, |
267 | struct lttng_ctx_field *field) | |
268 | { | |
269 | struct lttng_ctx *ctx; | |
270 | ||
271 | ctx = *ctx_p; | |
272 | ctx->nr_fields--; | |
8173ec7c | 273 | assert(&ctx->fields[ctx->nr_fields] == field); |
53569322 | 274 | assert(field->field_name == NULL); |
8020ceb5 MD |
275 | memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field)); |
276 | } | |
8020ceb5 MD |
277 | |
278 | void lttng_destroy_context(struct lttng_ctx *ctx) | |
279 | { | |
280 | int i; | |
281 | ||
282 | if (!ctx) | |
283 | return; | |
284 | for (i = 0; i < ctx->nr_fields; i++) { | |
285 | if (ctx->fields[i].destroy) | |
286 | ctx->fields[i].destroy(&ctx->fields[i]); | |
53569322 | 287 | free(ctx->fields[i].field_name); |
8020ceb5 | 288 | } |
8d8a24c8 MD |
289 | free(ctx->fields); |
290 | free(ctx); | |
8020ceb5 | 291 | } |
a0a3bef9 | 292 | |
53569322 MD |
293 | /* |
294 | * Can be safely performed concurrently with tracing using the struct | |
295 | * lttng_ctx. Using RCU update. Needs to match RCU read-side handling of | |
296 | * contexts. | |
297 | * | |
298 | * This does not allow adding, removing, or changing typing of the | |
299 | * contexts, since this needs to stay invariant for metadata. However, | |
300 | * it allows updating the handlers associated with all contexts matching | |
301 | * a provider (by name) while tracing is using it, in a way that ensures | |
302 | * a single RCU read-side critical section see either all old, or all | |
303 | * new handlers. | |
304 | */ | |
305 | int lttng_ust_context_set_provider_rcu(struct lttng_ctx **_ctx, | |
306 | const char *name, | |
307 | size_t (*get_size)(struct lttng_ctx_field *field, size_t offset), | |
308 | void (*record)(struct lttng_ctx_field *field, | |
309 | struct lttng_ust_lib_ring_buffer_ctx *ctx, | |
310 | struct lttng_channel *chan), | |
311 | void (*get_value)(struct lttng_ctx_field *field, | |
312 | struct lttng_ctx_value *value)) | |
313 | { | |
314 | int i, ret; | |
315 | struct lttng_ctx *ctx = *_ctx, *new_ctx; | |
316 | struct lttng_ctx_field *new_fields; | |
317 | ||
318 | if (!ctx || !lttng_find_context_provider(ctx, name)) | |
319 | return 0; | |
320 | /* | |
321 | * We have at least one instance of context for the provider. | |
322 | */ | |
323 | new_ctx = zmalloc(sizeof(*new_ctx)); | |
324 | if (!new_ctx) | |
325 | return -ENOMEM; | |
326 | *new_ctx = *ctx; | |
327 | new_fields = zmalloc(sizeof(*new_fields) * ctx->allocated_fields); | |
328 | if (!new_fields) { | |
329 | ret = -ENOMEM; | |
330 | goto field_error; | |
331 | } | |
332 | memcpy(new_fields, ctx->fields, | |
333 | sizeof(*new_fields) * ctx->allocated_fields); | |
334 | for (i = 0; i < ctx->nr_fields; i++) { | |
335 | if (strncmp(new_fields[i].event_field.name, | |
336 | name, strlen(name)) != 0) | |
337 | continue; | |
338 | new_fields[i].get_size = get_size; | |
339 | new_fields[i].record = record; | |
340 | new_fields[i].get_value = get_value; | |
341 | } | |
342 | new_ctx->fields = new_fields; | |
343 | rcu_assign_pointer(*_ctx, new_ctx); | |
344 | synchronize_trace(); | |
345 | free(ctx->fields); | |
346 | free(ctx); | |
347 | return 0; | |
348 | ||
349 | field_error: | |
350 | free(new_ctx); | |
351 | return ret; | |
352 | } | |
353 | ||
354 | int lttng_session_context_init(struct lttng_ctx **ctx) | |
a0a3bef9 MD |
355 | { |
356 | int ret; | |
357 | ||
53569322 | 358 | ret = lttng_add_pthread_id_to_ctx(ctx); |
a0a3bef9 MD |
359 | if (ret) { |
360 | WARN("Cannot add context lttng_add_pthread_id_to_ctx"); | |
53569322 | 361 | goto error; |
a0a3bef9 | 362 | } |
53569322 | 363 | ret = lttng_add_vtid_to_ctx(ctx); |
a0a3bef9 MD |
364 | if (ret) { |
365 | WARN("Cannot add context lttng_add_vtid_to_ctx"); | |
53569322 | 366 | goto error; |
a0a3bef9 | 367 | } |
53569322 | 368 | ret = lttng_add_vpid_to_ctx(ctx); |
a0a3bef9 MD |
369 | if (ret) { |
370 | WARN("Cannot add context lttng_add_vpid_to_ctx"); | |
53569322 | 371 | goto error; |
a0a3bef9 | 372 | } |
53569322 | 373 | ret = lttng_add_procname_to_ctx(ctx); |
a0a3bef9 MD |
374 | if (ret) { |
375 | WARN("Cannot add context lttng_add_procname_to_ctx"); | |
53569322 | 376 | goto error; |
a0a3bef9 | 377 | } |
53569322 | 378 | ret = lttng_add_cpu_id_to_ctx(ctx); |
c7ea8487 MD |
379 | if (ret) { |
380 | WARN("Cannot add context lttng_add_cpu_id_to_ctx"); | |
53569322 | 381 | goto error; |
c7ea8487 | 382 | } |
53569322 MD |
383 | lttng_context_update(*ctx); |
384 | return 0; | |
a0a3bef9 | 385 | |
53569322 MD |
386 | error: |
387 | lttng_destroy_context(*ctx); | |
388 | return ret; | |
a0a3bef9 | 389 | } |