Commit | Line | Data |
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852c2936 | 1 | /* |
c0c0989a | 2 | * SPDX-License-Identifier: LGPL-2.1-only |
852c2936 | 3 | * |
e92f3e28 | 4 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
852c2936 MD |
5 | */ |
6 | ||
3fbec7dc | 7 | #define _LGPL_SOURCE |
b4051ad8 | 8 | #include <stddef.h> |
fb31eb73 | 9 | #include <stdint.h> |
2657d1ba | 10 | #include <unistd.h> |
14641deb | 11 | #include <urcu/arch.h> |
96e80018 | 12 | #include <limits.h> |
14641deb | 13 | |
eae3c729 | 14 | #include <lttng/ust-utils.h> |
0466ac28 | 15 | #include <lttng/ringbuffer-context.h> |
3d3a2bb8 | 16 | |
0466ac28 | 17 | #include "ringbuffer-config.h" |
2fed87ae | 18 | #include "vatomic.h" |
4931a13e MD |
19 | #include "backend.h" |
20 | #include "frontend.h" | |
a6352fd4 | 21 | #include "smp.h" |
431d5cf0 | 22 | #include "shm.h" |
cd61d9bf | 23 | #include "ust-compat.h" |
852c2936 MD |
24 | |
25 | /** | |
26 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
27 | * @config: ring buffer instance configuration | |
28 | * @buf: the buffer struct | |
29 | * @size: total size of the buffer | |
30 | * @num_subbuf: number of subbuffers | |
31 | * @extra_reader_sb: need extra subbuffer for reader | |
32 | */ | |
33 | static | |
4cfec15c MD |
34 | int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config, |
35 | struct lttng_ust_lib_ring_buffer_backend *bufb, | |
852c2936 | 36 | size_t size, size_t num_subbuf, |
a6352fd4 | 37 | int extra_reader_sb, |
38fae1d3 | 38 | struct lttng_ust_shm_handle *handle, |
1d498196 | 39 | struct shm_object *shmobj) |
852c2936 | 40 | { |
34daae3e | 41 | struct channel_backend *chanb; |
852c2936 MD |
42 | unsigned long subbuf_size, mmap_offset = 0; |
43 | unsigned long num_subbuf_alloc; | |
852c2936 | 44 | unsigned long i; |
2657d1ba | 45 | long page_size; |
852c2936 | 46 | |
34daae3e MD |
47 | chanb = &shmp(handle, bufb->chan)->backend; |
48 | if (!chanb) | |
49 | return -EINVAL; | |
50 | ||
852c2936 MD |
51 | subbuf_size = chanb->subbuf_size; |
52 | num_subbuf_alloc = num_subbuf; | |
53 | ||
a6352fd4 | 54 | if (extra_reader_sb) |
852c2936 | 55 | num_subbuf_alloc++; |
852c2936 | 56 | |
b72687b8 | 57 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
58 | if (page_size <= 0) { |
59 | goto page_size_error; | |
60 | } | |
61 | ||
4cfec15c | 62 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
1d498196 | 63 | set_shmp(bufb->array, zalloc_shm(shmobj, |
4cfec15c | 64 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc)); |
b5a3dfa5 | 65 | if (caa_unlikely(!shmp(handle, bufb->array))) |
852c2936 MD |
66 | goto array_error; |
67 | ||
431d5cf0 MD |
68 | /* |
69 | * This is the largest element (the buffer pages) which needs to | |
2657d1ba | 70 | * be aligned on page size. |
431d5cf0 | 71 | */ |
2657d1ba | 72 | align_shm(shmobj, page_size); |
1d498196 | 73 | set_shmp(bufb->memory_map, zalloc_shm(shmobj, |
a6352fd4 | 74 | subbuf_size * num_subbuf_alloc)); |
b5a3dfa5 | 75 | if (caa_unlikely(!shmp(handle, bufb->memory_map))) |
a6352fd4 | 76 | goto memory_map_error; |
852c2936 MD |
77 | |
78 | /* Allocate backend pages array elements */ | |
79 | for (i = 0; i < num_subbuf_alloc; i++) { | |
4cfec15c | 80 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
aead2025 | 81 | set_shmp(shmp_index(handle, bufb->array, i)->shmp, |
1d498196 | 82 | zalloc_shm(shmobj, |
4cfec15c | 83 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages))); |
4746ae29 | 84 | if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp)) |
852c2936 MD |
85 | goto free_array; |
86 | } | |
87 | ||
88 | /* Allocate write-side subbuffer table */ | |
4cfec15c | 89 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
1d498196 | 90 | set_shmp(bufb->buf_wsb, zalloc_shm(shmobj, |
4cfec15c | 91 | sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) |
1d498196 | 92 | * num_subbuf)); |
b5a3dfa5 | 93 | if (caa_unlikely(!shmp(handle, bufb->buf_wsb))) |
852c2936 MD |
94 | goto free_array; |
95 | ||
34daae3e MD |
96 | for (i = 0; i < num_subbuf; i++) { |
97 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
98 | ||
99 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
100 | if (!sb) | |
101 | goto free_array; | |
102 | sb->id = subbuffer_id(config, 0, 1, i); | |
103 | } | |
852c2936 MD |
104 | |
105 | /* Assign read-side subbuffer table */ | |
106 | if (extra_reader_sb) | |
107 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
108 | num_subbuf_alloc - 1); | |
109 | else | |
110 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
111 | ||
1ff31389 | 112 | /* Allocate subbuffer packet counter table */ |
bf8f2ef2 | 113 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
1ff31389 JD |
114 | set_shmp(bufb->buf_cnt, zalloc_shm(shmobj, |
115 | sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) | |
116 | * num_subbuf)); | |
117 | if (caa_unlikely(!shmp(handle, bufb->buf_cnt))) | |
118 | goto free_wsb; | |
119 | ||
852c2936 MD |
120 | /* Assign pages to page index */ |
121 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
122 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
123 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
1d498196 MD |
124 | struct shm_ref ref; |
125 | ||
126 | ref.index = bufb->memory_map._ref.index; | |
127 | ref.offset = bufb->memory_map._ref.offset; | |
128 | ref.offset += i * subbuf_size; | |
129 | ||
34daae3e MD |
130 | sbp = shmp_index(handle, bufb->array, i); |
131 | if (!sbp) | |
132 | goto free_array; | |
133 | pages = shmp(handle, sbp->shmp); | |
134 | if (!pages) | |
135 | goto free_array; | |
136 | set_shmp(pages->p, ref); | |
852c2936 | 137 | if (config->output == RING_BUFFER_MMAP) { |
34daae3e | 138 | pages->mmap_offset = mmap_offset; |
852c2936 MD |
139 | mmap_offset += subbuf_size; |
140 | } | |
141 | } | |
852c2936 MD |
142 | return 0; |
143 | ||
1ff31389 JD |
144 | free_wsb: |
145 | /* bufb->buf_wsb will be freed by shm teardown */ | |
852c2936 | 146 | free_array: |
a6352fd4 MD |
147 | /* bufb->array[i] will be freed by shm teardown */ |
148 | memory_map_error: | |
149 | /* bufb->array will be freed by shm teardown */ | |
852c2936 | 150 | array_error: |
2657d1ba | 151 | page_size_error: |
852c2936 MD |
152 | return -ENOMEM; |
153 | } | |
154 | ||
4cfec15c | 155 | int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb, |
a6352fd4 | 156 | struct channel_backend *chanb, int cpu, |
38fae1d3 | 157 | struct lttng_ust_shm_handle *handle, |
1d498196 | 158 | struct shm_object *shmobj) |
852c2936 | 159 | { |
4cfec15c | 160 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 | 161 | |
1d498196 | 162 | set_shmp(bufb->chan, handle->chan._ref); |
852c2936 MD |
163 | bufb->cpu = cpu; |
164 | ||
165 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
166 | chanb->num_subbuf, | |
a6352fd4 | 167 | chanb->extra_reader_sb, |
1d498196 | 168 | handle, shmobj); |
852c2936 MD |
169 | } |
170 | ||
4cfec15c | 171 | void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb, |
38fae1d3 | 172 | struct lttng_ust_shm_handle *handle) |
852c2936 | 173 | { |
34daae3e MD |
174 | struct channel_backend *chanb; |
175 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
176 | unsigned long num_subbuf_alloc; |
177 | unsigned int i; | |
178 | ||
34daae3e MD |
179 | chanb = &shmp(handle, bufb->chan)->backend; |
180 | if (!chanb) | |
15500a1b | 181 | return; |
34daae3e MD |
182 | config = &chanb->config; |
183 | ||
852c2936 MD |
184 | num_subbuf_alloc = chanb->num_subbuf; |
185 | if (chanb->extra_reader_sb) | |
186 | num_subbuf_alloc++; | |
187 | ||
34daae3e MD |
188 | for (i = 0; i < chanb->num_subbuf; i++) { |
189 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
190 | ||
191 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
192 | if (!sb) | |
15500a1b | 193 | return; |
34daae3e MD |
194 | sb->id = subbuffer_id(config, 0, 1, i); |
195 | } | |
852c2936 MD |
196 | if (chanb->extra_reader_sb) |
197 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
198 | num_subbuf_alloc - 1); | |
199 | else | |
200 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
201 | ||
202 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
203 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
204 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
205 | ||
206 | sbp = shmp_index(handle, bufb->array, i); | |
207 | if (!sbp) | |
15500a1b | 208 | return; |
34daae3e MD |
209 | pages = shmp(handle, sbp->shmp); |
210 | if (!pages) | |
15500a1b | 211 | return; |
852c2936 | 212 | /* Don't reset mmap_offset */ |
34daae3e MD |
213 | v_set(config, &pages->records_commit, 0); |
214 | v_set(config, &pages->records_unread, 0); | |
215 | pages->data_size = 0; | |
852c2936 MD |
216 | /* Don't reset backend page and virt addresses */ |
217 | } | |
218 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
219 | v_set(config, &bufb->records_read, 0); | |
220 | } | |
221 | ||
222 | /* | |
223 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
224 | * each buffer when calling channel_backend_reset. | |
225 | */ | |
226 | void channel_backend_reset(struct channel_backend *chanb) | |
227 | { | |
5198080d MJ |
228 | struct lttng_ust_lib_ring_buffer_channel *chan = caa_container_of(chanb, |
229 | struct lttng_ust_lib_ring_buffer_channel, backend); | |
4cfec15c | 230 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 MD |
231 | |
232 | /* | |
233 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
234 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
235 | * priv, notifiers, config, cpumask and name. | |
236 | */ | |
237 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
238 | } | |
239 | ||
852c2936 MD |
240 | /** |
241 | * channel_backend_init - initialize a channel backend | |
242 | * @chanb: channel backend | |
243 | * @name: channel name | |
244 | * @config: client ring buffer configuration | |
852c2936 | 245 | * @parent: dentry of parent directory, %NULL for root directory |
2657d1ba | 246 | * @subbuf_size: size of sub-buffers (> page size, power of 2) |
852c2936 | 247 | * @num_subbuf: number of sub-buffers (power of 2) |
38fae1d3 | 248 | * @lttng_ust_shm_handle: shared memory handle |
5ea386c3 | 249 | * @stream_fds: stream file descriptors. |
852c2936 MD |
250 | * |
251 | * Returns channel pointer if successful, %NULL otherwise. | |
252 | * | |
253 | * Creates per-cpu channel buffers using the sizes and attributes | |
254 | * specified. The created channel buffer files will be named | |
255 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
256 | * | |
257 | * Called with CPU hotplug disabled. | |
258 | */ | |
259 | int channel_backend_init(struct channel_backend *chanb, | |
260 | const char *name, | |
4cfec15c | 261 | const struct lttng_ust_lib_ring_buffer_config *config, |
a3f61e7f | 262 | size_t subbuf_size, size_t num_subbuf, |
a9ff648c | 263 | struct lttng_ust_shm_handle *handle, |
5ea386c3 | 264 | const int *stream_fds) |
852c2936 | 265 | { |
5198080d MJ |
266 | struct lttng_ust_lib_ring_buffer_channel *chan = caa_container_of(chanb, |
267 | struct lttng_ust_lib_ring_buffer_channel, backend); | |
852c2936 MD |
268 | unsigned int i; |
269 | int ret; | |
6c1f7d8b | 270 | size_t shmsize = 0, num_subbuf_alloc; |
2657d1ba | 271 | long page_size; |
852c2936 MD |
272 | |
273 | if (!name) | |
274 | return -EPERM; | |
275 | ||
b72687b8 | 276 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
277 | if (page_size <= 0) { |
278 | return -ENOMEM; | |
279 | } | |
852c2936 | 280 | /* Check that the subbuffer size is larger than a page. */ |
2657d1ba | 281 | if (subbuf_size < page_size) |
852c2936 MD |
282 | return -EINVAL; |
283 | ||
284 | /* | |
12bcbbdb MD |
285 | * Make sure the number of subbuffers and subbuffer size are |
286 | * power of 2, and nonzero. | |
852c2936 | 287 | */ |
12bcbbdb | 288 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
e52b0723 | 289 | return -EINVAL; |
12bcbbdb | 290 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
e52b0723 | 291 | return -EINVAL; |
3d8e9399 MD |
292 | /* |
293 | * Overwrite mode buffers require at least 2 subbuffers per | |
294 | * buffer. | |
295 | */ | |
296 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
297 | return -EINVAL; | |
852c2936 MD |
298 | |
299 | ret = subbuffer_id_check_index(config, num_subbuf); | |
300 | if (ret) | |
301 | return ret; | |
302 | ||
852c2936 MD |
303 | chanb->buf_size = num_subbuf * subbuf_size; |
304 | chanb->subbuf_size = subbuf_size; | |
305 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
306 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
307 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
308 | chanb->extra_reader_sb = | |
309 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
310 | chanb->num_subbuf = num_subbuf; | |
a6352fd4 MD |
311 | strncpy(chanb->name, name, NAME_MAX); |
312 | chanb->name[NAME_MAX - 1] = '\0'; | |
193183fb | 313 | memcpy(&chanb->config, config, sizeof(*config)); |
852c2936 | 314 | |
1d498196 | 315 | /* Per-cpu buffer size: control (prior to backend) */ |
b72687b8 | 316 | shmsize = lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer)); |
4cfec15c | 317 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer); |
b72687b8 | 318 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_hot)); |
d2f09c1c | 319 | shmsize += sizeof(struct commit_counters_hot) * num_subbuf; |
b72687b8 | 320 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_cold)); |
d2f09c1c MD |
321 | shmsize += sizeof(struct commit_counters_cold) * num_subbuf; |
322 | /* Sampled timestamp end */ | |
b72687b8 | 323 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(uint64_t)); |
d2f09c1c | 324 | shmsize += sizeof(uint64_t) * num_subbuf; |
1d498196 MD |
325 | |
326 | /* Per-cpu buffer size: backend */ | |
327 | /* num_subbuf + 1 is the worse case */ | |
328 | num_subbuf_alloc = num_subbuf + 1; | |
b72687b8 | 329 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
4cfec15c | 330 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc; |
b72687b8 | 331 | shmsize += lttng_ust_offset_align(shmsize, page_size); |
1d498196 | 332 | shmsize += subbuf_size * num_subbuf_alloc; |
b72687b8 | 333 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
4cfec15c | 334 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc; |
b72687b8 | 335 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
4cfec15c | 336 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) * num_subbuf; |
b72687b8 | 337 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
bf8f2ef2 | 338 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) * num_subbuf; |
1d498196 | 339 | |
852c2936 | 340 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
4cfec15c | 341 | struct lttng_ust_lib_ring_buffer *buf; |
852c2936 | 342 | /* |
a6352fd4 | 343 | * We need to allocate for all possible cpus. |
852c2936 | 344 | */ |
852c2936 | 345 | for_each_possible_cpu(i) { |
1d498196 | 346 | struct shm_object *shmobj; |
5ea386c3 | 347 | |
74d81a6c | 348 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 349 | SHM_OBJECT_SHM, stream_fds[i], i); |
afdf9825 MD |
350 | if (!shmobj) |
351 | goto end; | |
4cfec15c MD |
352 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
353 | set_shmp(chanb->buf[i].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 MD |
354 | buf = shmp(handle, chanb->buf[i].shmp); |
355 | if (!buf) | |
356 | goto end; | |
5d61a504 | 357 | set_shmp(buf->self, chanb->buf[i].shmp._ref); |
1d498196 MD |
358 | ret = lib_ring_buffer_create(buf, chanb, i, |
359 | handle, shmobj); | |
852c2936 MD |
360 | if (ret) |
361 | goto free_bufs; /* cpu hotplug locked */ | |
362 | } | |
852c2936 | 363 | } else { |
1d498196 | 364 | struct shm_object *shmobj; |
4cfec15c | 365 | struct lttng_ust_lib_ring_buffer *buf; |
a6352fd4 | 366 | |
74d81a6c | 367 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 368 | SHM_OBJECT_SHM, stream_fds[0], -1); |
afdf9825 MD |
369 | if (!shmobj) |
370 | goto end; | |
4cfec15c MD |
371 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
372 | set_shmp(chanb->buf[0].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 | 373 | buf = shmp(handle, chanb->buf[0].shmp); |
a6352fd4 MD |
374 | if (!buf) |
375 | goto end; | |
cb14bae9 | 376 | set_shmp(buf->self, chanb->buf[0].shmp._ref); |
1d498196 MD |
377 | ret = lib_ring_buffer_create(buf, chanb, -1, |
378 | handle, shmobj); | |
852c2936 MD |
379 | if (ret) |
380 | goto free_bufs; | |
381 | } | |
382 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
383 | ||
384 | return 0; | |
385 | ||
386 | free_bufs: | |
a6352fd4 MD |
387 | /* We only free the buffer data upon shm teardown */ |
388 | end: | |
852c2936 MD |
389 | return -ENOMEM; |
390 | } | |
391 | ||
852c2936 MD |
392 | /** |
393 | * channel_backend_free - destroy the channel | |
394 | * @chan: the channel | |
395 | * | |
396 | * Destroy all channel buffers and frees the channel. | |
397 | */ | |
1d498196 | 398 | void channel_backend_free(struct channel_backend *chanb, |
38fae1d3 | 399 | struct lttng_ust_shm_handle *handle) |
852c2936 | 400 | { |
45e9e699 | 401 | /* SHM teardown takes care of everything */ |
852c2936 MD |
402 | } |
403 | ||
852c2936 MD |
404 | /** |
405 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
406 | * @bufb : buffer backend | |
407 | * @offset : offset within the buffer | |
408 | * @dest : destination address | |
409 | * @len : length to copy to destination | |
410 | * | |
411 | * Should be protected by get_subbuf/put_subbuf. | |
412 | * Returns the length copied. | |
413 | */ | |
4cfec15c | 414 | size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 415 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 416 | { |
34daae3e MD |
417 | struct channel_backend *chanb; |
418 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 419 | ssize_t orig_len; |
4cfec15c | 420 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 421 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 | 422 | unsigned long sb_bindex, id; |
99b99b47 | 423 | void *src; |
852c2936 | 424 | |
34daae3e MD |
425 | chanb = &shmp(handle, bufb->chan)->backend; |
426 | if (!chanb) | |
427 | return 0; | |
428 | config = &chanb->config; | |
852c2936 MD |
429 | orig_len = len; |
430 | offset &= chanb->buf_size - 1; | |
a6352fd4 | 431 | |
b5a3dfa5 | 432 | if (caa_unlikely(!len)) |
852c2936 | 433 | return 0; |
a6352fd4 MD |
434 | id = bufb->buf_rsb.id; |
435 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 436 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
437 | if (!rpages) |
438 | return 0; | |
a6352fd4 MD |
439 | /* |
440 | * Underlying layer should never ask for reads across | |
441 | * subbuffers. | |
442 | */ | |
443 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
444 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
445 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
446 | backend_pages = shmp(handle, rpages->shmp); |
447 | if (!backend_pages) | |
448 | return 0; | |
449 | src = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
450 | if (caa_unlikely(!src)) |
451 | return 0; | |
452 | memcpy(dest, src, len); | |
852c2936 MD |
453 | return orig_len; |
454 | } | |
852c2936 | 455 | |
852c2936 MD |
456 | /** |
457 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
458 | * @bufb : buffer backend | |
459 | * @offset : offset within the buffer | |
460 | * @dest : destination address | |
461 | * @len : destination's length | |
462 | * | |
0bf3c920 | 463 | * Return string's length, or -EINVAL on error. |
852c2936 | 464 | * Should be protected by get_subbuf/put_subbuf. |
0bf3c920 | 465 | * Destination length should be at least 1 to hold '\0'. |
852c2936 | 466 | */ |
4cfec15c | 467 | int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 468 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 469 | { |
34daae3e MD |
470 | struct channel_backend *chanb; |
471 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 472 | ssize_t string_len, orig_offset; |
852c2936 | 473 | char *str; |
4cfec15c | 474 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 475 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 MD |
476 | unsigned long sb_bindex, id; |
477 | ||
34daae3e MD |
478 | chanb = &shmp(handle, bufb->chan)->backend; |
479 | if (!chanb) | |
480 | return -EINVAL; | |
481 | config = &chanb->config; | |
0bf3c920 MD |
482 | if (caa_unlikely(!len)) |
483 | return -EINVAL; | |
852c2936 | 484 | offset &= chanb->buf_size - 1; |
852c2936 | 485 | orig_offset = offset; |
852c2936 MD |
486 | id = bufb->buf_rsb.id; |
487 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 488 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
489 | if (!rpages) |
490 | return -EINVAL; | |
a6352fd4 MD |
491 | /* |
492 | * Underlying layer should never ask for reads across | |
493 | * subbuffers. | |
494 | */ | |
495 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
852c2936 MD |
496 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
497 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
498 | backend_pages = shmp(handle, rpages->shmp); |
499 | if (!backend_pages) | |
500 | return -EINVAL; | |
501 | str = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
502 | if (caa_unlikely(!str)) |
503 | return -EINVAL; | |
a6352fd4 MD |
504 | string_len = strnlen(str, len); |
505 | if (dest && len) { | |
506 | memcpy(dest, str, string_len); | |
507 | ((char *)dest)[0] = 0; | |
508 | } | |
509 | return offset - orig_offset; | |
852c2936 | 510 | } |
852c2936 MD |
511 | |
512 | /** | |
513 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
514 | * @bufb : buffer backend | |
515 | * @offset : offset within the buffer. | |
516 | * | |
517 | * Return the address where a given offset is located (for read). | |
518 | * Should be used to get the current subbuffer header pointer. Given we know | |
22b22ce9 MD |
519 | * it's never on a page boundary, it's safe to read/write directly |
520 | * from/to this address, as long as the read/write is never bigger than | |
521 | * a page size. | |
852c2936 | 522 | */ |
4cfec15c | 523 | void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 524 | size_t offset, |
38fae1d3 | 525 | struct lttng_ust_shm_handle *handle) |
852c2936 | 526 | { |
4cfec15c | 527 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 528 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
529 | struct channel_backend *chanb; |
530 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
531 | unsigned long sb_bindex, id; |
532 | ||
34daae3e MD |
533 | chanb = &shmp(handle, bufb->chan)->backend; |
534 | if (!chanb) | |
535 | return NULL; | |
536 | config = &chanb->config; | |
852c2936 | 537 | offset &= chanb->buf_size - 1; |
852c2936 MD |
538 | id = bufb->buf_rsb.id; |
539 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 540 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
541 | if (!rpages) |
542 | return NULL; | |
852c2936 MD |
543 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
544 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
545 | backend_pages = shmp(handle, rpages->shmp); |
546 | if (!backend_pages) | |
547 | return NULL; | |
548 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 549 | } |
852c2936 MD |
550 | |
551 | /** | |
552 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
553 | * @bufb : buffer backend | |
554 | * @offset : offset within the buffer. | |
555 | * | |
556 | * Return the address where a given offset is located. | |
557 | * Should be used to get the current subbuffer header pointer. Given we know | |
558 | * it's always at the beginning of a page, it's safe to write directly to this | |
559 | * address, as long as the write is never bigger than a page size. | |
560 | */ | |
4cfec15c | 561 | void *lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 562 | size_t offset, |
38fae1d3 | 563 | struct lttng_ust_shm_handle *handle) |
852c2936 | 564 | { |
a6352fd4 | 565 | size_t sbidx; |
4cfec15c | 566 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 567 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
568 | struct channel_backend *chanb; |
569 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 | 570 | unsigned long sb_bindex, id; |
34daae3e | 571 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; |
852c2936 | 572 | |
34daae3e MD |
573 | chanb = &shmp(handle, bufb->chan)->backend; |
574 | if (!chanb) | |
575 | return NULL; | |
576 | config = &chanb->config; | |
852c2936 MD |
577 | offset &= chanb->buf_size - 1; |
578 | sbidx = offset >> chanb->subbuf_size_order; | |
34daae3e MD |
579 | sb = shmp_index(handle, bufb->buf_wsb, sbidx); |
580 | if (!sb) | |
581 | return NULL; | |
582 | id = sb->id; | |
852c2936 | 583 | sb_bindex = subbuffer_id_get_index(config, id); |
4746ae29 | 584 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
585 | if (!rpages) |
586 | return NULL; | |
852c2936 MD |
587 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
588 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
589 | backend_pages = shmp(handle, rpages->shmp); |
590 | if (!backend_pages) | |
591 | return NULL; | |
592 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 593 | } |