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