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 | |
b72687b8 | 14 | #include <lttng/align.h> |
4318ae1b | 15 | #include <lttng/ringbuffer-config.h> |
2fed87ae | 16 | #include "vatomic.h" |
4931a13e MD |
17 | #include "backend.h" |
18 | #include "frontend.h" | |
a6352fd4 | 19 | #include "smp.h" |
431d5cf0 | 20 | #include "shm.h" |
cd61d9bf | 21 | #include "ust-compat.h" |
852c2936 MD |
22 | |
23 | /** | |
24 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
25 | * @config: ring buffer instance configuration | |
26 | * @buf: the buffer struct | |
27 | * @size: total size of the buffer | |
28 | * @num_subbuf: number of subbuffers | |
29 | * @extra_reader_sb: need extra subbuffer for reader | |
30 | */ | |
31 | static | |
4cfec15c MD |
32 | int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config, |
33 | struct lttng_ust_lib_ring_buffer_backend *bufb, | |
852c2936 | 34 | size_t size, size_t num_subbuf, |
a6352fd4 | 35 | int extra_reader_sb, |
38fae1d3 | 36 | struct lttng_ust_shm_handle *handle, |
1d498196 | 37 | struct shm_object *shmobj) |
852c2936 | 38 | { |
34daae3e | 39 | struct channel_backend *chanb; |
852c2936 MD |
40 | unsigned long subbuf_size, mmap_offset = 0; |
41 | unsigned long num_subbuf_alloc; | |
852c2936 | 42 | unsigned long i; |
2657d1ba | 43 | long page_size; |
852c2936 | 44 | |
34daae3e MD |
45 | chanb = &shmp(handle, bufb->chan)->backend; |
46 | if (!chanb) | |
47 | return -EINVAL; | |
48 | ||
852c2936 MD |
49 | subbuf_size = chanb->subbuf_size; |
50 | num_subbuf_alloc = num_subbuf; | |
51 | ||
a6352fd4 | 52 | if (extra_reader_sb) |
852c2936 | 53 | num_subbuf_alloc++; |
852c2936 | 54 | |
b72687b8 | 55 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
56 | if (page_size <= 0) { |
57 | goto page_size_error; | |
58 | } | |
59 | ||
4cfec15c | 60 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
1d498196 | 61 | set_shmp(bufb->array, zalloc_shm(shmobj, |
4cfec15c | 62 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc)); |
b5a3dfa5 | 63 | if (caa_unlikely(!shmp(handle, bufb->array))) |
852c2936 MD |
64 | goto array_error; |
65 | ||
431d5cf0 MD |
66 | /* |
67 | * This is the largest element (the buffer pages) which needs to | |
2657d1ba | 68 | * be aligned on page size. |
431d5cf0 | 69 | */ |
2657d1ba | 70 | align_shm(shmobj, page_size); |
1d498196 | 71 | set_shmp(bufb->memory_map, zalloc_shm(shmobj, |
a6352fd4 | 72 | subbuf_size * num_subbuf_alloc)); |
b5a3dfa5 | 73 | if (caa_unlikely(!shmp(handle, bufb->memory_map))) |
a6352fd4 | 74 | goto memory_map_error; |
852c2936 MD |
75 | |
76 | /* Allocate backend pages array elements */ | |
77 | for (i = 0; i < num_subbuf_alloc; i++) { | |
4cfec15c | 78 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
aead2025 | 79 | set_shmp(shmp_index(handle, bufb->array, i)->shmp, |
1d498196 | 80 | zalloc_shm(shmobj, |
4cfec15c | 81 | sizeof(struct lttng_ust_lib_ring_buffer_backend_pages))); |
4746ae29 | 82 | if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp)) |
852c2936 MD |
83 | goto free_array; |
84 | } | |
85 | ||
86 | /* Allocate write-side subbuffer table */ | |
4cfec15c | 87 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
1d498196 | 88 | set_shmp(bufb->buf_wsb, zalloc_shm(shmobj, |
4cfec15c | 89 | sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) |
1d498196 | 90 | * num_subbuf)); |
b5a3dfa5 | 91 | if (caa_unlikely(!shmp(handle, bufb->buf_wsb))) |
852c2936 MD |
92 | goto free_array; |
93 | ||
34daae3e MD |
94 | for (i = 0; i < num_subbuf; i++) { |
95 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
96 | ||
97 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
98 | if (!sb) | |
99 | goto free_array; | |
100 | sb->id = subbuffer_id(config, 0, 1, i); | |
101 | } | |
852c2936 MD |
102 | |
103 | /* Assign read-side subbuffer table */ | |
104 | if (extra_reader_sb) | |
105 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
106 | num_subbuf_alloc - 1); | |
107 | else | |
108 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
109 | ||
1ff31389 | 110 | /* Allocate subbuffer packet counter table */ |
bf8f2ef2 | 111 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
1ff31389 JD |
112 | set_shmp(bufb->buf_cnt, zalloc_shm(shmobj, |
113 | sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) | |
114 | * num_subbuf)); | |
115 | if (caa_unlikely(!shmp(handle, bufb->buf_cnt))) | |
116 | goto free_wsb; | |
117 | ||
852c2936 MD |
118 | /* Assign pages to page index */ |
119 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
120 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
121 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
1d498196 MD |
122 | struct shm_ref ref; |
123 | ||
124 | ref.index = bufb->memory_map._ref.index; | |
125 | ref.offset = bufb->memory_map._ref.offset; | |
126 | ref.offset += i * subbuf_size; | |
127 | ||
34daae3e MD |
128 | sbp = shmp_index(handle, bufb->array, i); |
129 | if (!sbp) | |
130 | goto free_array; | |
131 | pages = shmp(handle, sbp->shmp); | |
132 | if (!pages) | |
133 | goto free_array; | |
134 | set_shmp(pages->p, ref); | |
852c2936 | 135 | if (config->output == RING_BUFFER_MMAP) { |
34daae3e | 136 | pages->mmap_offset = mmap_offset; |
852c2936 MD |
137 | mmap_offset += subbuf_size; |
138 | } | |
139 | } | |
852c2936 MD |
140 | return 0; |
141 | ||
1ff31389 JD |
142 | free_wsb: |
143 | /* bufb->buf_wsb will be freed by shm teardown */ | |
852c2936 | 144 | free_array: |
a6352fd4 MD |
145 | /* bufb->array[i] will be freed by shm teardown */ |
146 | memory_map_error: | |
147 | /* bufb->array will be freed by shm teardown */ | |
852c2936 | 148 | array_error: |
2657d1ba | 149 | page_size_error: |
852c2936 MD |
150 | return -ENOMEM; |
151 | } | |
152 | ||
4cfec15c | 153 | int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb, |
a6352fd4 | 154 | struct channel_backend *chanb, int cpu, |
38fae1d3 | 155 | struct lttng_ust_shm_handle *handle, |
1d498196 | 156 | struct shm_object *shmobj) |
852c2936 | 157 | { |
4cfec15c | 158 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 | 159 | |
1d498196 | 160 | set_shmp(bufb->chan, handle->chan._ref); |
852c2936 MD |
161 | bufb->cpu = cpu; |
162 | ||
163 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
164 | chanb->num_subbuf, | |
a6352fd4 | 165 | chanb->extra_reader_sb, |
1d498196 | 166 | handle, shmobj); |
852c2936 MD |
167 | } |
168 | ||
4cfec15c | 169 | void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb, |
38fae1d3 | 170 | struct lttng_ust_shm_handle *handle) |
852c2936 | 171 | { |
34daae3e MD |
172 | struct channel_backend *chanb; |
173 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
174 | unsigned long num_subbuf_alloc; |
175 | unsigned int i; | |
176 | ||
34daae3e MD |
177 | chanb = &shmp(handle, bufb->chan)->backend; |
178 | if (!chanb) | |
15500a1b | 179 | return; |
34daae3e MD |
180 | config = &chanb->config; |
181 | ||
852c2936 MD |
182 | num_subbuf_alloc = chanb->num_subbuf; |
183 | if (chanb->extra_reader_sb) | |
184 | num_subbuf_alloc++; | |
185 | ||
34daae3e MD |
186 | for (i = 0; i < chanb->num_subbuf; i++) { |
187 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; | |
188 | ||
189 | sb = shmp_index(handle, bufb->buf_wsb, i); | |
190 | if (!sb) | |
15500a1b | 191 | return; |
34daae3e MD |
192 | sb->id = subbuffer_id(config, 0, 1, i); |
193 | } | |
852c2936 MD |
194 | if (chanb->extra_reader_sb) |
195 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
196 | num_subbuf_alloc - 1); | |
197 | else | |
198 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
199 | ||
200 | for (i = 0; i < num_subbuf_alloc; i++) { | |
34daae3e MD |
201 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp; |
202 | struct lttng_ust_lib_ring_buffer_backend_pages *pages; | |
203 | ||
204 | sbp = shmp_index(handle, bufb->array, i); | |
205 | if (!sbp) | |
15500a1b | 206 | return; |
34daae3e MD |
207 | pages = shmp(handle, sbp->shmp); |
208 | if (!pages) | |
15500a1b | 209 | return; |
852c2936 | 210 | /* Don't reset mmap_offset */ |
34daae3e MD |
211 | v_set(config, &pages->records_commit, 0); |
212 | v_set(config, &pages->records_unread, 0); | |
213 | pages->data_size = 0; | |
852c2936 MD |
214 | /* Don't reset backend page and virt addresses */ |
215 | } | |
216 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
217 | v_set(config, &bufb->records_read, 0); | |
218 | } | |
219 | ||
220 | /* | |
221 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
222 | * each buffer when calling channel_backend_reset. | |
223 | */ | |
224 | void channel_backend_reset(struct channel_backend *chanb) | |
225 | { | |
14641deb | 226 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
4cfec15c | 227 | const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config; |
852c2936 MD |
228 | |
229 | /* | |
230 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
231 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
232 | * priv, notifiers, config, cpumask and name. | |
233 | */ | |
234 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
235 | } | |
236 | ||
852c2936 MD |
237 | /** |
238 | * channel_backend_init - initialize a channel backend | |
239 | * @chanb: channel backend | |
240 | * @name: channel name | |
241 | * @config: client ring buffer configuration | |
852c2936 | 242 | * @parent: dentry of parent directory, %NULL for root directory |
2657d1ba | 243 | * @subbuf_size: size of sub-buffers (> page size, power of 2) |
852c2936 | 244 | * @num_subbuf: number of sub-buffers (power of 2) |
38fae1d3 | 245 | * @lttng_ust_shm_handle: shared memory handle |
5ea386c3 | 246 | * @stream_fds: stream file descriptors. |
852c2936 MD |
247 | * |
248 | * Returns channel pointer if successful, %NULL otherwise. | |
249 | * | |
250 | * Creates per-cpu channel buffers using the sizes and attributes | |
251 | * specified. The created channel buffer files will be named | |
252 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
253 | * | |
254 | * Called with CPU hotplug disabled. | |
255 | */ | |
256 | int channel_backend_init(struct channel_backend *chanb, | |
257 | const char *name, | |
4cfec15c | 258 | const struct lttng_ust_lib_ring_buffer_config *config, |
a3f61e7f | 259 | size_t subbuf_size, size_t num_subbuf, |
a9ff648c | 260 | struct lttng_ust_shm_handle *handle, |
5ea386c3 | 261 | const int *stream_fds) |
852c2936 | 262 | { |
14641deb | 263 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
852c2936 MD |
264 | unsigned int i; |
265 | int ret; | |
6c1f7d8b | 266 | size_t shmsize = 0, num_subbuf_alloc; |
2657d1ba | 267 | long page_size; |
852c2936 MD |
268 | |
269 | if (!name) | |
270 | return -EPERM; | |
271 | ||
b72687b8 | 272 | page_size = LTTNG_UST_PAGE_SIZE; |
2657d1ba MD |
273 | if (page_size <= 0) { |
274 | return -ENOMEM; | |
275 | } | |
852c2936 | 276 | /* Check that the subbuffer size is larger than a page. */ |
2657d1ba | 277 | if (subbuf_size < page_size) |
852c2936 MD |
278 | return -EINVAL; |
279 | ||
280 | /* | |
12bcbbdb MD |
281 | * Make sure the number of subbuffers and subbuffer size are |
282 | * power of 2, and nonzero. | |
852c2936 | 283 | */ |
12bcbbdb | 284 | if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) |
e52b0723 | 285 | return -EINVAL; |
12bcbbdb | 286 | if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) |
e52b0723 | 287 | return -EINVAL; |
3d8e9399 MD |
288 | /* |
289 | * Overwrite mode buffers require at least 2 subbuffers per | |
290 | * buffer. | |
291 | */ | |
292 | if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2) | |
293 | return -EINVAL; | |
852c2936 MD |
294 | |
295 | ret = subbuffer_id_check_index(config, num_subbuf); | |
296 | if (ret) | |
297 | return ret; | |
298 | ||
852c2936 MD |
299 | chanb->buf_size = num_subbuf * subbuf_size; |
300 | chanb->subbuf_size = subbuf_size; | |
301 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
302 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
303 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
304 | chanb->extra_reader_sb = | |
305 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
306 | chanb->num_subbuf = num_subbuf; | |
a6352fd4 MD |
307 | strncpy(chanb->name, name, NAME_MAX); |
308 | chanb->name[NAME_MAX - 1] = '\0'; | |
193183fb | 309 | memcpy(&chanb->config, config, sizeof(*config)); |
852c2936 | 310 | |
1d498196 | 311 | /* Per-cpu buffer size: control (prior to backend) */ |
b72687b8 | 312 | shmsize = lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer)); |
4cfec15c | 313 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer); |
b72687b8 | 314 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_hot)); |
d2f09c1c | 315 | shmsize += sizeof(struct commit_counters_hot) * num_subbuf; |
b72687b8 | 316 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct commit_counters_cold)); |
d2f09c1c MD |
317 | shmsize += sizeof(struct commit_counters_cold) * num_subbuf; |
318 | /* Sampled timestamp end */ | |
b72687b8 | 319 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(uint64_t)); |
d2f09c1c | 320 | shmsize += sizeof(uint64_t) * num_subbuf; |
1d498196 MD |
321 | |
322 | /* Per-cpu buffer size: backend */ | |
323 | /* num_subbuf + 1 is the worse case */ | |
324 | num_subbuf_alloc = num_subbuf + 1; | |
b72687b8 | 325 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp)); |
4cfec15c | 326 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc; |
b72687b8 | 327 | shmsize += lttng_ust_offset_align(shmsize, page_size); |
1d498196 | 328 | shmsize += subbuf_size * num_subbuf_alloc; |
b72687b8 | 329 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages)); |
4cfec15c | 330 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc; |
b72687b8 | 331 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer)); |
4cfec15c | 332 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) * num_subbuf; |
b72687b8 | 333 | shmsize += lttng_ust_offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_counts)); |
bf8f2ef2 | 334 | shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_counts) * num_subbuf; |
1d498196 | 335 | |
852c2936 | 336 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { |
4cfec15c | 337 | struct lttng_ust_lib_ring_buffer *buf; |
852c2936 | 338 | /* |
a6352fd4 | 339 | * We need to allocate for all possible cpus. |
852c2936 | 340 | */ |
852c2936 | 341 | for_each_possible_cpu(i) { |
1d498196 | 342 | struct shm_object *shmobj; |
5ea386c3 | 343 | |
74d81a6c | 344 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 345 | SHM_OBJECT_SHM, stream_fds[i], i); |
afdf9825 MD |
346 | if (!shmobj) |
347 | goto end; | |
4cfec15c MD |
348 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
349 | set_shmp(chanb->buf[i].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 MD |
350 | buf = shmp(handle, chanb->buf[i].shmp); |
351 | if (!buf) | |
352 | goto end; | |
5d61a504 | 353 | set_shmp(buf->self, chanb->buf[i].shmp._ref); |
1d498196 MD |
354 | ret = lib_ring_buffer_create(buf, chanb, i, |
355 | handle, shmobj); | |
852c2936 MD |
356 | if (ret) |
357 | goto free_bufs; /* cpu hotplug locked */ | |
358 | } | |
852c2936 | 359 | } else { |
1d498196 | 360 | struct shm_object *shmobj; |
4cfec15c | 361 | struct lttng_ust_lib_ring_buffer *buf; |
a6352fd4 | 362 | |
74d81a6c | 363 | shmobj = shm_object_table_alloc(handle->table, shmsize, |
4b68c31f | 364 | SHM_OBJECT_SHM, stream_fds[0], -1); |
afdf9825 MD |
365 | if (!shmobj) |
366 | goto end; | |
4cfec15c MD |
367 | align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); |
368 | set_shmp(chanb->buf[0].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer))); | |
1d498196 | 369 | buf = shmp(handle, chanb->buf[0].shmp); |
a6352fd4 MD |
370 | if (!buf) |
371 | goto end; | |
cb14bae9 | 372 | set_shmp(buf->self, chanb->buf[0].shmp._ref); |
1d498196 MD |
373 | ret = lib_ring_buffer_create(buf, chanb, -1, |
374 | handle, shmobj); | |
852c2936 MD |
375 | if (ret) |
376 | goto free_bufs; | |
377 | } | |
378 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
379 | ||
380 | return 0; | |
381 | ||
382 | free_bufs: | |
a6352fd4 MD |
383 | /* We only free the buffer data upon shm teardown */ |
384 | end: | |
852c2936 MD |
385 | return -ENOMEM; |
386 | } | |
387 | ||
852c2936 MD |
388 | /** |
389 | * channel_backend_free - destroy the channel | |
390 | * @chan: the channel | |
391 | * | |
392 | * Destroy all channel buffers and frees the channel. | |
393 | */ | |
1d498196 | 394 | void channel_backend_free(struct channel_backend *chanb, |
38fae1d3 | 395 | struct lttng_ust_shm_handle *handle) |
852c2936 | 396 | { |
45e9e699 | 397 | /* SHM teardown takes care of everything */ |
852c2936 MD |
398 | } |
399 | ||
852c2936 MD |
400 | /** |
401 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
402 | * @bufb : buffer backend | |
403 | * @offset : offset within the buffer | |
404 | * @dest : destination address | |
405 | * @len : length to copy to destination | |
406 | * | |
407 | * Should be protected by get_subbuf/put_subbuf. | |
408 | * Returns the length copied. | |
409 | */ | |
4cfec15c | 410 | size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 411 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 412 | { |
34daae3e MD |
413 | struct channel_backend *chanb; |
414 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 415 | ssize_t orig_len; |
4cfec15c | 416 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 417 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 | 418 | unsigned long sb_bindex, id; |
99b99b47 | 419 | void *src; |
852c2936 | 420 | |
34daae3e MD |
421 | chanb = &shmp(handle, bufb->chan)->backend; |
422 | if (!chanb) | |
423 | return 0; | |
424 | config = &chanb->config; | |
852c2936 MD |
425 | orig_len = len; |
426 | offset &= chanb->buf_size - 1; | |
a6352fd4 | 427 | |
b5a3dfa5 | 428 | if (caa_unlikely(!len)) |
852c2936 | 429 | return 0; |
a6352fd4 MD |
430 | id = bufb->buf_rsb.id; |
431 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 432 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
433 | if (!rpages) |
434 | return 0; | |
a6352fd4 MD |
435 | /* |
436 | * Underlying layer should never ask for reads across | |
437 | * subbuffers. | |
438 | */ | |
439 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
440 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
441 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
442 | backend_pages = shmp(handle, rpages->shmp); |
443 | if (!backend_pages) | |
444 | return 0; | |
445 | src = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
446 | if (caa_unlikely(!src)) |
447 | return 0; | |
448 | memcpy(dest, src, len); | |
852c2936 MD |
449 | return orig_len; |
450 | } | |
852c2936 | 451 | |
852c2936 MD |
452 | /** |
453 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
454 | * @bufb : buffer backend | |
455 | * @offset : offset within the buffer | |
456 | * @dest : destination address | |
457 | * @len : destination's length | |
458 | * | |
0bf3c920 | 459 | * Return string's length, or -EINVAL on error. |
852c2936 | 460 | * Should be protected by get_subbuf/put_subbuf. |
0bf3c920 | 461 | * Destination length should be at least 1 to hold '\0'. |
852c2936 | 462 | */ |
4cfec15c | 463 | int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset, |
38fae1d3 | 464 | void *dest, size_t len, struct lttng_ust_shm_handle *handle) |
852c2936 | 465 | { |
34daae3e MD |
466 | struct channel_backend *chanb; |
467 | const struct lttng_ust_lib_ring_buffer_config *config; | |
a6352fd4 | 468 | ssize_t string_len, orig_offset; |
852c2936 | 469 | char *str; |
4cfec15c | 470 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 471 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
852c2936 MD |
472 | unsigned long sb_bindex, id; |
473 | ||
34daae3e MD |
474 | chanb = &shmp(handle, bufb->chan)->backend; |
475 | if (!chanb) | |
476 | return -EINVAL; | |
477 | config = &chanb->config; | |
0bf3c920 MD |
478 | if (caa_unlikely(!len)) |
479 | return -EINVAL; | |
852c2936 | 480 | offset &= chanb->buf_size - 1; |
852c2936 | 481 | orig_offset = offset; |
852c2936 MD |
482 | id = bufb->buf_rsb.id; |
483 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 484 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
485 | if (!rpages) |
486 | return -EINVAL; | |
a6352fd4 MD |
487 | /* |
488 | * Underlying layer should never ask for reads across | |
489 | * subbuffers. | |
490 | */ | |
491 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
852c2936 MD |
492 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
493 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
494 | backend_pages = shmp(handle, rpages->shmp); |
495 | if (!backend_pages) | |
496 | return -EINVAL; | |
497 | str = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
99b99b47 MD |
498 | if (caa_unlikely(!str)) |
499 | return -EINVAL; | |
a6352fd4 MD |
500 | string_len = strnlen(str, len); |
501 | if (dest && len) { | |
502 | memcpy(dest, str, string_len); | |
503 | ((char *)dest)[0] = 0; | |
504 | } | |
505 | return offset - orig_offset; | |
852c2936 | 506 | } |
852c2936 MD |
507 | |
508 | /** | |
509 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
510 | * @bufb : buffer backend | |
511 | * @offset : offset within the buffer. | |
512 | * | |
513 | * Return the address where a given offset is located (for read). | |
514 | * Should be used to get the current subbuffer header pointer. Given we know | |
22b22ce9 MD |
515 | * it's never on a page boundary, it's safe to read/write directly |
516 | * from/to this address, as long as the read/write is never bigger than | |
517 | * a page size. | |
852c2936 | 518 | */ |
4cfec15c | 519 | void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 520 | size_t offset, |
38fae1d3 | 521 | struct lttng_ust_shm_handle *handle) |
852c2936 | 522 | { |
4cfec15c | 523 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 524 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
525 | struct channel_backend *chanb; |
526 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 MD |
527 | unsigned long sb_bindex, id; |
528 | ||
34daae3e MD |
529 | chanb = &shmp(handle, bufb->chan)->backend; |
530 | if (!chanb) | |
531 | return NULL; | |
532 | config = &chanb->config; | |
852c2936 | 533 | offset &= chanb->buf_size - 1; |
852c2936 MD |
534 | id = bufb->buf_rsb.id; |
535 | sb_bindex = subbuffer_id_get_index(config, id); | |
4746ae29 | 536 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
537 | if (!rpages) |
538 | return NULL; | |
852c2936 MD |
539 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
540 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
541 | backend_pages = shmp(handle, rpages->shmp); |
542 | if (!backend_pages) | |
543 | return NULL; | |
544 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 545 | } |
852c2936 MD |
546 | |
547 | /** | |
548 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
549 | * @bufb : buffer backend | |
550 | * @offset : offset within the buffer. | |
551 | * | |
552 | * Return the address where a given offset is located. | |
553 | * Should be used to get the current subbuffer header pointer. Given we know | |
554 | * it's always at the beginning of a page, it's safe to write directly to this | |
555 | * address, as long as the write is never bigger than a page size. | |
556 | */ | |
4cfec15c | 557 | void *lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb, |
1d498196 | 558 | size_t offset, |
38fae1d3 | 559 | struct lttng_ust_shm_handle *handle) |
852c2936 | 560 | { |
a6352fd4 | 561 | size_t sbidx; |
4cfec15c | 562 | struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages; |
15500a1b | 563 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
34daae3e MD |
564 | struct channel_backend *chanb; |
565 | const struct lttng_ust_lib_ring_buffer_config *config; | |
852c2936 | 566 | unsigned long sb_bindex, id; |
34daae3e | 567 | struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb; |
852c2936 | 568 | |
34daae3e MD |
569 | chanb = &shmp(handle, bufb->chan)->backend; |
570 | if (!chanb) | |
571 | return NULL; | |
572 | config = &chanb->config; | |
852c2936 MD |
573 | offset &= chanb->buf_size - 1; |
574 | sbidx = offset >> chanb->subbuf_size_order; | |
34daae3e MD |
575 | sb = shmp_index(handle, bufb->buf_wsb, sbidx); |
576 | if (!sb) | |
577 | return NULL; | |
578 | id = sb->id; | |
852c2936 | 579 | sb_bindex = subbuffer_id_get_index(config, id); |
4746ae29 | 580 | rpages = shmp_index(handle, bufb->array, sb_bindex); |
15500a1b MD |
581 | if (!rpages) |
582 | return NULL; | |
852c2936 MD |
583 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
584 | && subbuffer_id_is_noref(config, id)); | |
15500a1b MD |
585 | backend_pages = shmp(handle, rpages->shmp); |
586 | if (!backend_pages) | |
587 | return NULL; | |
588 | return shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1)); | |
852c2936 | 589 | } |