Commit | Line | Data |
---|---|---|
852c2936 MD |
1 | /* |
2 | * ring_buffer_backend.c | |
3 | * | |
e92f3e28 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
852c2936 | 5 | * |
e92f3e28 MD |
6 | * This library is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; only | |
9 | * version 2.1 of the License. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
852c2936 MD |
19 | */ |
20 | ||
3fbec7dc | 21 | #define _LGPL_SOURCE |
b4051ad8 | 22 | #include <stddef.h> |
fb31eb73 | 23 | #include <stdint.h> |
2657d1ba | 24 | #include <unistd.h> |
14641deb | 25 | #include <urcu/arch.h> |
96e80018 | 26 | #include <limits.h> |
14641deb | 27 | |
b72687b8 | 28 | #include <lttng/align.h> |
4318ae1b | 29 | #include <lttng/ringbuffer-config.h> |
2fed87ae | 30 | #include "vatomic.h" |
4931a13e MD |
31 | #include "backend.h" |
32 | #include "frontend.h" | |
a6352fd4 | 33 | #include "smp.h" |
431d5cf0 | 34 | #include "shm.h" |
852c2936 MD |
35 | |
36 | /** | |
37 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
38 | * @config: ring buffer instance configuration | |
39 | * @buf: the buffer struct | |
40 | * @size: total size of the buffer | |
41 | * @num_subbuf: number of subbuffers | |
42 | * @extra_reader_sb: need extra subbuffer for reader | |
43 | */ | |
44 | static | |
4cfec15c MD |
45 | int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config, |
46 | struct lttng_ust_lib_ring_buffer_backend *bufb, | |
852c2936 | 47 | size_t size, size_t num_subbuf, |
a6352fd4 | 48 | int extra_reader_sb, |
38fae1d3 | 49 | struct lttng_ust_shm_handle *handle, |
1d498196 | 50 | struct shm_object *shmobj) |
852c2936 | 51 | { |
34daae3e | 52 | struct channel_backend *chanb; |
852c2936 MD |
53 | unsigned long subbuf_size, mmap_offset = 0; |
54 | unsigned long num_subbuf_alloc; | |
852c2936 | 55 | unsigned long i; |
2657d1ba | 56 | long page_size; |
852c2936 | 57 | |
34daae3e MD |
58 | chanb = &shmp(handle, bufb->chan)->backend; |
59 | if (!chanb) | |
60 | return -EINVAL; | |
61 | ||
852c2936 MD |
62 | subbuf_size = chanb->subbuf_size; |
63 | num_subbuf_alloc = num_subbuf; | |
64 | ||
a6352fd4 | 65 | if (extra_reader_sb) |
852c2936 | 66 | num_subbuf_alloc++; |
852c2936 | 67 | |
b72687b8 | 68 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
69 | if (page_size <= 0) { |
70 | goto page_size_error; | |
71 | } | |
72 | ||
4cfec15c | 73 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
1d498196 | 74 | set_shmp(bufb->array, zalloc_shm(shmobj, |
4cfec15c | 75 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc)); |
b5a3dfa5 | 76 | if (caa_unlikely(!shmp(handle, bufb->array))) |
852c2936 MD |
77 | goto array_error; |
78 | ||
431d5cf0 MD |
79 | /* |
80 | * This is the largest element (the buffer pages) which needs to | |
2657d1ba | 81 | * be aligned on page size. |
431d5cf0 | 82 | */ |
2657d1ba | 83 | align_shm(shmobj, page_size); |
1d498196 | 84 | set_shmp(bufb->memory_map, zalloc_shm(shmobj, |
a6352fd4 | 85 | subbuf_size * num_subbuf_alloc)); |
b5a3dfa5 | 86 | if (caa_unlikely(!shmp(handle, bufb->memory_map))) |
a6352fd4 | 87 | goto memory_map_error; |
852c2936 MD |
88 | |
89 | /* Allocate backend pages array elements */ | |
90 | for (i = 0; i < num_subbuf_alloc; i++) { | |
4cfec15c | 91 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
aead2025 | 92 | set_shmp(shmp_index(handle, bufb->array, i)->shmp, |
1d498196 | 93 | zalloc_shm(shmobj, |
4cfec15c | 94 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages))); |
4746ae29 | 95 | if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp)) |
852c2936 MD |
96 | goto free_array; |
97 | } | |
98 | ||
99 | /* Allocate write-side subbuffer table */ | |
4cfec15c | 100 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
1d498196 | 101 | set_shmp(bufb->buf_wsb, zalloc_shm(shmobj, |
4cfec15c | 102 | sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) |
1d498196 | 103 | * num_subbuf)); |
b5a3dfa5 | 104 | if (caa_unlikely(!shmp(handle, bufb->buf_wsb))) |
852c2936 MD |
105 | goto free_array; |
106 | ||
34daae3e MD |
107 | for (i = 0; i < num_subbuf; i++) { |
108 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
109 | ||
110 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
111 | if (!sb) | |
112 | goto free_array; | |
113 | sb->id = subbuffer_id(config, 0, 1, i); | |
114 | } | |
852c2936 MD |
115 | |
116 | /* Assign read-side subbuffer table */ | |
117 | if (extra_reader_sb) | |
118 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
119 | num_subbuf_alloc - 1); | |
120 | else | |
121 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
122 | ||
1ff31389 | 123 | /* Allocate subbuffer packet counter table */ |
bf8f2ef2 | 124 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
1ff31389 JD |
125 | set_shmp(bufb->buf_cnt, zalloc_shm(shmobj, |
126 | sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) | |
127 | * num_subbuf)); | |
128 | if (caa_unlikely(!shmp(handle, bufb->buf_cnt))) | |
129 | goto free_wsb; | |
130 | ||
852c2936 MD |
131 | /* Assign pages to page index */ |
132 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
133 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
134 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
1d498196 MD |
135 | struct shm_ref ref; |
136 | ||
137 | ref.index = bufb->memory_map._ref.index; | |
138 | ref.offset = bufb->memory_map._ref.offset; | |
139 | ref.offset += i * subbuf_size; | |
140 | ||
34daae3e MD |
141 | sbp = shmp_index(handle, bufb->array, i); |
142 | if (!sbp) | |
143 | goto free_array; | |
144 | pages = shmp(handle, sbp->shmp); | |
145 | if (!pages) | |
146 | goto free_array; | |
147 | set_shmp(pages->p, ref); | |
852c2936 | 148 | if (config->output == RING_BUFFER_MMAP) { |
34daae3e | 149 | pages->mmap_offset = mmap_offset; |
852c2936 MD |
150 | mmap_offset += subbuf_size; |
151 | } | |
152 | } | |
852c2936 MD |
153 | return 0; |
154 | ||
1ff31389 JD |
155 | free_wsb: |
156 | /* bufb->buf_wsb will be freed by shm teardown */ | |
852c2936 | 157 | free_array: |
a6352fd4 MD |
158 | /* bufb->array[i] will be freed by shm teardown */ |
159 | memory_map_error: | |
160 | /* bufb->array will be freed by shm teardown */ | |
852c2936 | 161 | array_error: |
2657d1ba | 162 | page_size_error: |
852c2936 MD |
163 | return -ENOMEM; |
164 | } | |
165 | ||
4cfec15c | 166 | int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb, |
a6352fd4 | 167 | struct channel_backend *chanb, int cpu, |
38fae1d3 | 168 | struct lttng_ust_shm_handle *handle, |
1d498196 | 169 | struct shm_object *shmobj) |
852c2936 | 170 | { |
4cfec15c | 171 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 | 172 | |
1d498196 | 173 | set_shmp(bufb->chan, handle->chan._ref); |
852c2936 MD |
174 | bufb->cpu = cpu; |
175 | ||
176 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
177 | chanb->num_subbuf, | |
a6352fd4 | 178 | chanb->extra_reader_sb, |
1d498196 | 179 | handle, shmobj); |
852c2936 MD |
180 | } |
181 | ||
4cfec15c | 182 | void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb, |
38fae1d3 | 183 | struct lttng_ust_shm_handle *handle) |
852c2936 | 184 | { |
34daae3e MD |
185 | struct channel_backend *chanb; |
186 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
187 | unsigned long num_subbuf_alloc; |
188 | unsigned int i; | |
189 | ||
34daae3e MD |
190 | chanb = &shmp(handle, bufb->chan)->backend; |
191 | if (!chanb) | |
15500a1b | 192 | return; |
34daae3e MD |
193 | config = &chanb->config; |
194 | ||
852c2936 MD |
195 | num_subbuf_alloc = chanb->num_subbuf; |
196 | if (chanb->extra_reader_sb) | |
197 | num_subbuf_alloc++; | |
198 | ||
34daae3e MD |
199 | for (i = 0; i < chanb->num_subbuf; i++) { |
200 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
201 | ||
202 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
203 | if (!sb) | |
15500a1b | 204 | return; |
34daae3e MD |
205 | sb->id = subbuffer_id(config, 0, 1, i); |
206 | } | |
852c2936 MD |
207 | if (chanb->extra_reader_sb) |
208 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
209 | num_subbuf_alloc - 1); | |
210 | else | |
211 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
212 | ||
213 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
214 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
215 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
216 | ||
217 | sbp = shmp_index(handle, bufb->array, i); | |
218 | if (!sbp) | |
15500a1b | 219 | return; |
34daae3e MD |
220 | pages = shmp(handle, sbp->shmp); |
221 | if (!pages) | |
15500a1b | 222 | return; |
852c2936 | 223 | /* Don't reset mmap_offset */ |
34daae3e MD |
224 | v_set(config, &pages->records_commit, 0); |
225 | v_set(config, &pages->records_unread, 0); | |
226 | pages->data_size = 0; | |
852c2936 MD |
227 | /* Don't reset backend page and virt addresses */ |
228 | } | |
229 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
230 | v_set(config, &bufb->records_read, 0); | |
231 | } | |
232 | ||
233 | /* | |
234 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
235 | * each buffer when calling channel_backend_reset. | |
236 | */ | |
237 | void channel_backend_reset(struct channel_backend *chanb) | |
238 | { | |
14641deb | 239 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
4cfec15c | 240 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 MD |
241 | |
242 | /* | |
243 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
244 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
245 | * priv, notifiers, config, cpumask and name. | |
246 | */ | |
247 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
248 | } | |
249 | ||
852c2936 MD |
250 | /** |
251 | * channel_backend_init - initialize a channel backend | |
252 | * @chanb: channel backend | |
253 | * @name: channel name | |
254 | * @config: client ring buffer configuration | |
852c2936 | 255 | * @parent: dentry of parent directory, %NULL for root directory |
2657d1ba | 256 | * @subbuf_size: size of sub-buffers (> page size, power of 2) |
852c2936 | 257 | * @num_subbuf: number of sub-buffers (power of 2) |
38fae1d3 | 258 | * @lttng_ust_shm_handle: shared memory handle |
5ea386c3 | 259 | * @stream_fds: stream file descriptors. |
852c2936 MD |
260 | * |
261 | * Returns channel pointer if successful, %NULL otherwise. | |
262 | * | |
263 | * Creates per-cpu channel buffers using the sizes and attributes | |
264 | * specified. The created channel buffer files will be named | |
265 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
266 | * | |
267 | * Called with CPU hotplug disabled. | |
268 | */ | |
269 | int channel_backend_init(struct channel_backend *chanb, | |
270 | const char *name, | |
4cfec15c | 271 | const struct lttng_ust_lib_ring_buffer_config *config, |
a3f61e7f | 272 | size_t subbuf_size, size_t num_subbuf, |
a9ff648c | 273 | struct lttng_ust_shm_handle *handle, |
5ea386c3 | 274 | const int *stream_fds) |
852c2936 | 275 | { |
14641deb | 276 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
852c2936 MD |
277 | unsigned int i; |
278 | int ret; | |
6c1f7d8b | 279 | size_t shmsize = 0, num_subbuf_alloc; |
2657d1ba | 280 | long page_size; |
852c2936 MD |
281 | |
282 | if (!name) | |
283 | return -EPERM; | |
284 | ||
b72687b8 | 285 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
286 | if (page_size <= 0) { |
287 | return -ENOMEM; | |
288 | } | |
852c2936 | 289 | /* Check that the subbuffer size is larger than a page. */ |
2657d1ba | 290 | if (subbuf_size < page_size) |
852c2936 MD |
291 | return -EINVAL; |
292 | ||
293 | /* | |
12bcbbdb MD |
294 | * Make sure the number of subbuffers and subbuffer size are |
295 | * power of 2, and nonzero. | |
852c2936 | 296 | */ |
12bcbbdb | 297 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
e52b0723 | 298 | return -EINVAL; |
12bcbbdb | 299 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
e52b0723 | 300 | return -EINVAL; |
3d8e9399 MD |
301 | /* |
302 | * Overwrite mode buffers require at least 2 subbuffers per | |
303 | * buffer. | |
304 | */ | |
305 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
306 | return -EINVAL; | |
852c2936 MD |
307 | |
308 | ret = subbuffer_id_check_index(config, num_subbuf); | |
309 | if (ret) | |
310 | return ret; | |
311 | ||
852c2936 MD |
312 | chanb->buf_size = num_subbuf * subbuf_size; |
313 | chanb->subbuf_size = subbuf_size; | |
314 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
315 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
316 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
317 | chanb->extra_reader_sb = | |
318 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
319 | chanb->num_subbuf = num_subbuf; | |
a6352fd4 MD |
320 | strncpy(chanb->name, name, NAME_MAX); |
321 | chanb->name[NAME_MAX - 1] = '\0'; | |
193183fb | 322 | memcpy(&chanb->config, config, sizeof(*config)); |
852c2936 | 323 | |
1d498196 | 324 | /* Per-cpu buffer size: control (prior to backend) */ |
b72687b8 | 325 | shmsize = lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer)); |
4cfec15c | 326 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer); |
b72687b8 | 327 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_hot)); |
d2f09c1c | 328 | shmsize += sizeof(struct commit_counters_hot) * num_subbuf; |
b72687b8 | 329 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_cold)); |
d2f09c1c MD |
330 | shmsize += sizeof(struct commit_counters_cold) * num_subbuf; |
331 | /* Sampled timestamp end */ | |
b72687b8 | 332 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(uint64_t)); |
d2f09c1c | 333 | shmsize += sizeof(uint64_t) * num_subbuf; |
1d498196 MD |
334 | |
335 | /* Per-cpu buffer size: backend */ | |
336 | /* num_subbuf + 1 is the worse case */ | |
337 | num_subbuf_alloc = num_subbuf + 1; | |
b72687b8 | 338 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
4cfec15c | 339 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc; |
b72687b8 | 340 | shmsize += lttng_ust_offset_align(shmsize, page_size); |
1d498196 | 341 | shmsize += subbuf_size * num_subbuf_alloc; |
b72687b8 | 342 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
4cfec15c | 343 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc; |
b72687b8 | 344 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
4cfec15c | 345 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) * num_subbuf; |
b72687b8 | 346 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
bf8f2ef2 | 347 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) * num_subbuf; |
1d498196 | 348 | |
852c2936 | 349 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
4cfec15c | 350 | struct lttng_ust_lib_ring_buffer *buf; |
852c2936 | 351 | /* |
a6352fd4 | 352 | * We need to allocate for all possible cpus. |
852c2936 | 353 | */ |
852c2936 | 354 | for_each_possible_cpu(i) { |
1d498196 | 355 | struct shm_object *shmobj; |
5ea386c3 | 356 | |
74d81a6c | 357 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 358 | SHM_OBJECT_SHM, stream_fds[i], i); |
afdf9825 MD |
359 | if (!shmobj) |
360 | goto end; | |
4cfec15c MD |
361 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
362 | set_shmp(chanb->buf[i].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 MD |
363 | buf = shmp(handle, chanb->buf[i].shmp); |
364 | if (!buf) | |
365 | goto end; | |
5d61a504 | 366 | set_shmp(buf->self, chanb->buf[i].shmp._ref); |
1d498196 MD |
367 | ret = lib_ring_buffer_create(buf, chanb, i, |
368 | handle, shmobj); | |
852c2936 MD |
369 | if (ret) |
370 | goto free_bufs; /* cpu hotplug locked */ | |
371 | } | |
852c2936 | 372 | } else { |
1d498196 | 373 | struct shm_object *shmobj; |
4cfec15c | 374 | struct lttng_ust_lib_ring_buffer *buf; |
a6352fd4 | 375 | |
74d81a6c | 376 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 377 | SHM_OBJECT_SHM, stream_fds[0], -1); |
afdf9825 MD |
378 | if (!shmobj) |
379 | goto end; | |
4cfec15c MD |
380 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
381 | set_shmp(chanb->buf[0].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 | 382 | buf = shmp(handle, chanb->buf[0].shmp); |
a6352fd4 MD |
383 | if (!buf) |
384 | goto end; | |
cb14bae9 | 385 | set_shmp(buf->self, chanb->buf[0].shmp._ref); |
1d498196 MD |
386 | ret = lib_ring_buffer_create(buf, chanb, -1, |
387 | handle, shmobj); | |
852c2936 MD |
388 | if (ret) |
389 | goto free_bufs; | |
390 | } | |
391 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
392 | ||
393 | return 0; | |
394 | ||
395 | free_bufs: | |
a6352fd4 MD |
396 | /* We only free the buffer data upon shm teardown */ |
397 | end: | |
852c2936 MD |
398 | return -ENOMEM; |
399 | } | |
400 | ||
852c2936 MD |
401 | /** |
402 | * channel_backend_free - destroy the channel | |
403 | * @chan: the channel | |
404 | * | |
405 | * Destroy all channel buffers and frees the channel. | |
406 | */ | |
1d498196 | 407 | void channel_backend_free(struct channel_backend *chanb, |
38fae1d3 | 408 | struct lttng_ust_shm_handle *handle) |
852c2936 | 409 | { |
45e9e699 | 410 | /* SHM teardown takes care of everything */ |
852c2936 MD |
411 | } |
412 | ||
852c2936 MD |
413 | /** |
414 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
415 | * @bufb : buffer backend | |
416 | * @offset : offset within the buffer | |
417 | * @dest : destination address | |
418 | * @len : length to copy to destination | |
419 | * | |
420 | * Should be protected by get_subbuf/put_subbuf. | |
421 | * Returns the length copied. | |
422 | */ | |
4cfec15c | 423 | size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 424 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 425 | { |
34daae3e MD |
426 | struct channel_backend *chanb; |
427 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 428 | ssize_t orig_len; |
4cfec15c | 429 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 430 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 | 431 | unsigned long sb_bindex, id; |
99b99b47 | 432 | void *src; |
852c2936 | 433 | |
34daae3e MD |
434 | chanb = &shmp(handle, bufb->chan)->backend; |
435 | if (!chanb) | |
436 | return 0; | |
437 | config = &chanb->config; | |
852c2936 MD |
438 | orig_len = len; |
439 | offset &= chanb->buf_size - 1; | |
a6352fd4 | 440 | |
b5a3dfa5 | 441 | if (caa_unlikely(!len)) |
852c2936 | 442 | return 0; |
a6352fd4 MD |
443 | id = bufb->buf_rsb.id; |
444 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 445 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
446 | if (!rpages) |
447 | return 0; | |
a6352fd4 MD |
448 | /* |
449 | * Underlying layer should never ask for reads across | |
450 | * subbuffers. | |
451 | */ | |
452 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
453 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
454 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
455 | backend_pages = shmp(handle, rpages->shmp); |
456 | if (!backend_pages) | |
457 | return 0; | |
458 | src = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
459 | if (caa_unlikely(!src)) |
460 | return 0; | |
461 | memcpy(dest, src, len); | |
852c2936 MD |
462 | return orig_len; |
463 | } | |
852c2936 | 464 | |
852c2936 MD |
465 | /** |
466 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
467 | * @bufb : buffer backend | |
468 | * @offset : offset within the buffer | |
469 | * @dest : destination address | |
470 | * @len : destination's length | |
471 | * | |
0bf3c920 | 472 | * Return string's length, or -EINVAL on error. |
852c2936 | 473 | * Should be protected by get_subbuf/put_subbuf. |
0bf3c920 | 474 | * Destination length should be at least 1 to hold '\0'. |
852c2936 | 475 | */ |
4cfec15c | 476 | int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 477 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 478 | { |
34daae3e MD |
479 | struct channel_backend *chanb; |
480 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 481 | ssize_t string_len, orig_offset; |
852c2936 | 482 | char *str; |
4cfec15c | 483 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 484 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 MD |
485 | unsigned long sb_bindex, id; |
486 | ||
34daae3e MD |
487 | chanb = &shmp(handle, bufb->chan)->backend; |
488 | if (!chanb) | |
489 | return -EINVAL; | |
490 | config = &chanb->config; | |
0bf3c920 MD |
491 | if (caa_unlikely(!len)) |
492 | return -EINVAL; | |
852c2936 | 493 | offset &= chanb->buf_size - 1; |
852c2936 | 494 | orig_offset = offset; |
852c2936 MD |
495 | id = bufb->buf_rsb.id; |
496 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 497 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
498 | if (!rpages) |
499 | return -EINVAL; | |
a6352fd4 MD |
500 | /* |
501 | * Underlying layer should never ask for reads across | |
502 | * subbuffers. | |
503 | */ | |
504 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
852c2936 MD |
505 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
506 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
507 | backend_pages = shmp(handle, rpages->shmp); |
508 | if (!backend_pages) | |
509 | return -EINVAL; | |
510 | str = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
511 | if (caa_unlikely(!str)) |
512 | return -EINVAL; | |
a6352fd4 MD |
513 | string_len = strnlen(str, len); |
514 | if (dest && len) { | |
515 | memcpy(dest, str, string_len); | |
516 | ((char *)dest)[0] = 0; | |
517 | } | |
518 | return offset - orig_offset; | |
852c2936 | 519 | } |
852c2936 MD |
520 | |
521 | /** | |
522 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
523 | * @bufb : buffer backend | |
524 | * @offset : offset within the buffer. | |
525 | * | |
526 | * Return the address where a given offset is located (for read). | |
527 | * Should be used to get the current subbuffer header pointer. Given we know | |
22b22ce9 MD |
528 | * it's never on a page boundary, it's safe to read/write directly |
529 | * from/to this address, as long as the read/write is never bigger than | |
530 | * a page size. | |
852c2936 | 531 | */ |
4cfec15c | 532 | void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 533 | size_t offset, |
38fae1d3 | 534 | struct lttng_ust_shm_handle *handle) |
852c2936 | 535 | { |
4cfec15c | 536 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 537 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
538 | struct channel_backend *chanb; |
539 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
540 | unsigned long sb_bindex, id; |
541 | ||
34daae3e MD |
542 | chanb = &shmp(handle, bufb->chan)->backend; |
543 | if (!chanb) | |
544 | return NULL; | |
545 | config = &chanb->config; | |
852c2936 | 546 | offset &= chanb->buf_size - 1; |
852c2936 MD |
547 | id = bufb->buf_rsb.id; |
548 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 549 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
550 | if (!rpages) |
551 | return NULL; | |
852c2936 MD |
552 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
553 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
554 | backend_pages = shmp(handle, rpages->shmp); |
555 | if (!backend_pages) | |
556 | return NULL; | |
557 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 558 | } |
852c2936 MD |
559 | |
560 | /** | |
561 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
562 | * @bufb : buffer backend | |
563 | * @offset : offset within the buffer. | |
564 | * | |
565 | * Return the address where a given offset is located. | |
566 | * Should be used to get the current subbuffer header pointer. Given we know | |
567 | * it's always at the beginning of a page, it's safe to write directly to this | |
568 | * address, as long as the write is never bigger than a page size. | |
569 | */ | |
4cfec15c | 570 | void *lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 571 | size_t offset, |
38fae1d3 | 572 | struct lttng_ust_shm_handle *handle) |
852c2936 | 573 | { |
a6352fd4 | 574 | size_t sbidx; |
4cfec15c | 575 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 576 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
577 | struct channel_backend *chanb; |
578 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 | 579 | unsigned long sb_bindex, id; |
34daae3e | 580 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; |
852c2936 | 581 | |
34daae3e MD |
582 | chanb = &shmp(handle, bufb->chan)->backend; |
583 | if (!chanb) | |
584 | return NULL; | |
585 | config = &chanb->config; | |
852c2936 MD |
586 | offset &= chanb->buf_size - 1; |
587 | sbidx = offset >> chanb->subbuf_size_order; | |
34daae3e MD |
588 | sb = shmp_index(handle, bufb->buf_wsb, sbidx); |
589 | if (!sb) | |
590 | return NULL; | |
591 | id = sb->id; | |
852c2936 | 592 | sb_bindex = subbuffer_id_get_index(config, id); |
4746ae29 | 593 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
594 | if (!rpages) |
595 | return NULL; | |
852c2936 MD |
596 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
597 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
598 | backend_pages = shmp(handle, rpages->shmp); |
599 | if (!backend_pages) | |
600 | return NULL; | |
601 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 602 | } |