Allow channel mode override in snapshot sessions
[lttng-tools.git] / src / bin / lttng-sessiond / channel.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _LGPL_SOURCE
20 #include <inttypes.h>
21 #include <string.h>
22 #include <unistd.h>
23
24 #include <common/common.h>
25 #include <common/defaults.h>
26 #include <common/sessiond-comm/sessiond-comm.h>
27
28 #include "channel.h"
29 #include "lttng-sessiond.h"
30 #include "kernel.h"
31 #include "ust-ctl.h"
32 #include "utils.h"
33 #include "ust-app.h"
34 #include "agent.h"
35
36 /*
37 * Return allocated channel attributes.
38 */
39 struct lttng_channel *channel_new_default_attr(int dom,
40 enum lttng_buffer_type type)
41 {
42 struct lttng_channel *chan;
43 const char *channel_name = DEFAULT_CHANNEL_NAME;
44
45 chan = zmalloc(sizeof(struct lttng_channel));
46 if (chan == NULL) {
47 PERROR("zmalloc channel init");
48 goto error_alloc;
49 }
50
51 /* Same for all domains. */
52 chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
53 chan->attr.tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
54 chan->attr.tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
55
56 switch (dom) {
57 case LTTNG_DOMAIN_KERNEL:
58 assert(type == LTTNG_BUFFER_GLOBAL);
59 chan->attr.subbuf_size =
60 default_get_kernel_channel_subbuf_size();
61 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
62 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
63 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
64 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
65 chan->attr.live_timer_interval = DEFAULT_KERNEL_CHANNEL_LIVE_TIMER;
66 break;
67 case LTTNG_DOMAIN_JUL:
68 channel_name = DEFAULT_JUL_CHANNEL_NAME;
69 goto common_ust;
70 case LTTNG_DOMAIN_LOG4J:
71 channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
72 goto common_ust;
73 case LTTNG_DOMAIN_PYTHON:
74 channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
75 goto common_ust;
76 case LTTNG_DOMAIN_UST:
77 common_ust:
78 switch (type) {
79 case LTTNG_BUFFER_PER_UID:
80 chan->attr.subbuf_size = default_get_ust_uid_channel_subbuf_size();
81 chan->attr.num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
82 chan->attr.output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
83 chan->attr.switch_timer_interval =
84 DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
85 chan->attr.read_timer_interval =
86 DEFAULT_UST_UID_CHANNEL_READ_TIMER;
87 chan->attr.live_timer_interval =
88 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
89 break;
90 case LTTNG_BUFFER_PER_PID:
91 default:
92 chan->attr.subbuf_size = default_get_ust_pid_channel_subbuf_size();
93 chan->attr.num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
94 chan->attr.output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
95 chan->attr.switch_timer_interval =
96 DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
97 chan->attr.read_timer_interval =
98 DEFAULT_UST_PID_CHANNEL_READ_TIMER;
99 chan->attr.live_timer_interval =
100 DEFAULT_UST_UID_CHANNEL_LIVE_TIMER;
101 break;
102 }
103 break;
104 default:
105 goto error; /* Not implemented */
106 }
107
108 if (snprintf(chan->name, sizeof(chan->name), "%s",
109 channel_name) < 0) {
110 PERROR("snprintf default channel name");
111 goto error;
112 }
113 return chan;
114
115 error:
116 free(chan);
117 error_alloc:
118 return NULL;
119 }
120
121 /*
122 * Disable kernel channel of the kernel session.
123 */
124 int channel_kernel_disable(struct ltt_kernel_session *ksession,
125 char *channel_name)
126 {
127 int ret;
128 struct ltt_kernel_channel *kchan;
129
130 assert(ksession);
131 assert(channel_name);
132
133 kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
134 if (kchan == NULL) {
135 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
136 goto error;
137 }
138
139 /* Only if channel is enabled disable it. */
140 if (kchan->enabled == 1) {
141 ret = kernel_disable_channel(kchan);
142 if (ret < 0 && ret != -EEXIST) {
143 ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
144 goto error;
145 }
146 }
147
148 ret = LTTNG_OK;
149
150 error:
151 return ret;
152 }
153
154 /*
155 * Enable kernel channel of the kernel session.
156 */
157 int channel_kernel_enable(struct ltt_kernel_session *ksession,
158 struct ltt_kernel_channel *kchan)
159 {
160 int ret;
161
162 assert(ksession);
163 assert(kchan);
164
165 if (kchan->enabled == 0) {
166 ret = kernel_enable_channel(kchan);
167 if (ret < 0) {
168 ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
169 goto error;
170 }
171 } else {
172 ret = LTTNG_ERR_KERN_CHAN_EXIST;
173 goto error;
174 }
175
176 ret = LTTNG_OK;
177
178 error:
179 return ret;
180 }
181
182 static int channel_validate(struct lttng_channel *attr)
183 {
184 /*
185 * The ringbuffer (both in user space and kernel) behaves badly
186 * in overwrite mode and with less than 2 subbuffers so block it
187 * right away and send back an invalid attribute error.
188 */
189 if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
190 return -1;
191 }
192 return 0;
193 }
194
195 /*
196 * Create kernel channel of the kernel session and notify kernel thread.
197 */
198 int channel_kernel_create(struct ltt_kernel_session *ksession,
199 struct lttng_channel *attr, int kernel_pipe)
200 {
201 int ret;
202 struct lttng_channel *defattr = NULL;
203
204 assert(ksession);
205
206 /* Creating channel attributes if needed */
207 if (attr == NULL) {
208 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
209 LTTNG_BUFFER_GLOBAL);
210 if (defattr == NULL) {
211 ret = LTTNG_ERR_FATAL;
212 goto error;
213 }
214 attr = defattr;
215 }
216
217 /*
218 * Set the overwrite mode for this channel based on the session
219 * type unless the client explicitly overrides the channel mode.
220 */
221 if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
222 attr->attr.overwrite = !!ksession->snapshot_mode;
223 }
224
225 /* Enforce mmap output for snapshot sessions. */
226 if (ksession->snapshot_mode) {
227 attr->attr.output = LTTNG_EVENT_MMAP;
228 }
229
230 /* Validate common channel properties. */
231 if (channel_validate(attr) < 0) {
232 ret = LTTNG_ERR_INVALID;
233 goto error;
234 }
235
236 /* Channel not found, creating it */
237 ret = kernel_create_channel(ksession, attr);
238 if (ret < 0) {
239 ret = LTTNG_ERR_KERN_CHAN_FAIL;
240 goto error;
241 }
242
243 /* Notify kernel thread that there is a new channel */
244 ret = notify_thread_pipe(kernel_pipe);
245 if (ret < 0) {
246 ret = LTTNG_ERR_FATAL;
247 goto error;
248 }
249
250 ret = LTTNG_OK;
251 error:
252 free(defattr);
253 return ret;
254 }
255
256 /*
257 * Enable UST channel for session and domain.
258 */
259 int channel_ust_enable(struct ltt_ust_session *usess,
260 struct ltt_ust_channel *uchan)
261 {
262 int ret = LTTNG_OK;
263
264 assert(usess);
265 assert(uchan);
266
267 /* If already enabled, everything is OK */
268 if (uchan->enabled) {
269 DBG3("Channel %s already enabled. Skipping", uchan->name);
270 ret = LTTNG_ERR_UST_CHAN_EXIST;
271 goto end;
272 }
273
274 DBG2("Channel %s being enabled in UST domain", uchan->name);
275
276 /*
277 * Enable channel for UST global domain on all applications. Ignore return
278 * value here since whatever error we got, it means that the channel was
279 * not created on one or many registered applications and we can not report
280 * this to the user yet. However, at this stage, the channel was
281 * successfully created on the session daemon side so the enable-channel
282 * command is a success.
283 */
284 (void) ust_app_enable_channel_glb(usess, uchan);
285
286 uchan->enabled = 1;
287 DBG2("Channel %s enabled successfully", uchan->name);
288
289 end:
290 return ret;
291 }
292
293 /*
294 * Create UST channel for session and domain.
295 */
296 int channel_ust_create(struct ltt_ust_session *usess,
297 struct lttng_channel *attr, enum lttng_buffer_type type)
298 {
299 int ret = LTTNG_OK;
300 struct ltt_ust_channel *uchan = NULL;
301 struct lttng_channel *defattr = NULL;
302 enum lttng_domain_type domain = LTTNG_DOMAIN_UST;
303
304 assert(usess);
305
306 /* Creating channel attributes if needed */
307 if (attr == NULL) {
308 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST, type);
309 if (defattr == NULL) {
310 ret = LTTNG_ERR_FATAL;
311 goto error;
312 }
313 attr = defattr;
314 } else {
315 /*
316 * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
317 * based on the default name.
318 */
319 if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
320 domain = LTTNG_DOMAIN_JUL;
321 } else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
322 domain = LTTNG_DOMAIN_LOG4J;
323 } else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
324 domain = LTTNG_DOMAIN_PYTHON;
325 }
326 }
327
328 /*
329 * Set the overwrite mode for this channel based on the session
330 * type unless the client explicitly overrides the channel mode.
331 */
332 if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
333 attr->attr.overwrite = !!usess->snapshot_mode;
334 }
335
336 /* Enforce mmap output for snapshot sessions. */
337 if (usess->snapshot_mode) {
338 attr->attr.output = LTTNG_EVENT_MMAP;
339 }
340
341 /* Validate common channel properties. */
342 if (channel_validate(attr) < 0) {
343 ret = LTTNG_ERR_INVALID;
344 goto error;
345 }
346
347 /*
348 * Validate UST buffer size and number of buffers: must both be power of 2
349 * and nonzero. We validate right here for UST, because applications will
350 * not report the error to the user (unlike kernel tracing).
351 */
352 if (!attr->attr.subbuf_size ||
353 (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
354 ret = LTTNG_ERR_INVALID;
355 goto error;
356 }
357
358 /*
359 * Invalid subbuffer size if it's lower then the page size.
360 */
361 if (attr->attr.subbuf_size < page_size) {
362 ret = LTTNG_ERR_INVALID;
363 goto error;
364 }
365
366 if (!attr->attr.num_subbuf ||
367 (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
368 ret = LTTNG_ERR_INVALID;
369 goto error;
370 }
371
372 if (attr->attr.output != LTTNG_EVENT_MMAP) {
373 ret = LTTNG_ERR_NOT_SUPPORTED;
374 goto error;
375 }
376
377 /*
378 * The tracefile_size should not be < to the subbuf_size, otherwise
379 * we won't be able to write the packets on disk
380 */
381 if ((attr->attr.tracefile_size > 0) &&
382 (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
383 ret = LTTNG_ERR_INVALID;
384 goto error;
385 }
386
387 /* Validate buffer type. */
388 switch (type) {
389 case LTTNG_BUFFER_PER_PID:
390 break;
391 case LTTNG_BUFFER_PER_UID:
392 break;
393 default:
394 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
395 goto error;
396 }
397
398 /* Create UST channel */
399 uchan = trace_ust_create_channel(attr, domain);
400 if (uchan == NULL) {
401 ret = LTTNG_ERR_FATAL;
402 goto error;
403 }
404
405 uchan->enabled = 1;
406 if (trace_ust_is_max_id(usess->used_channel_id)) {
407 ret = LTTNG_ERR_UST_CHAN_FAIL;
408 goto error;
409 }
410 uchan->id = trace_ust_get_next_chan_id(usess);
411
412 DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
413 uchan->name, type, uchan->id);
414
415 /* Flag session buffer type. */
416 if (!usess->buffer_type_changed) {
417 usess->buffer_type = type;
418 usess->buffer_type_changed = 1;
419 } else if (usess->buffer_type != type) {
420 /* Buffer type was already set. Refuse to create channel. */
421 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
422 goto error_free_chan;
423 }
424
425 /* Enable channel for global domain */
426 ret = ust_app_create_channel_glb(usess, uchan);
427 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
428 ret = LTTNG_ERR_UST_CHAN_FAIL;
429 goto error_free_chan;
430 }
431
432 /* Adding the channel to the channel hash table. */
433 rcu_read_lock();
434 if (strncmp(uchan->name, DEFAULT_METADATA_NAME,
435 sizeof(uchan->name))) {
436 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
437 } else {
438 /*
439 * Copy channel attribute to session if this is metadata so if NO
440 * application exists we can access that data in the shadow copy during
441 * the global update of newly registered application.
442 */
443 memcpy(&usess->metadata_attr, &uchan->attr,
444 sizeof(usess->metadata_attr));
445 }
446 rcu_read_unlock();
447
448 DBG2("Channel %s created successfully", uchan->name);
449 if (domain != LTTNG_DOMAIN_UST) {
450 struct agent *agt = trace_ust_find_agent(usess, domain);
451
452 if (!agt) {
453 agt = agent_create(domain);
454 if (!agt) {
455 ret = LTTNG_ERR_NOMEM;
456 goto error_free_chan;
457 }
458 agent_add(agt, usess->agents);
459 }
460 }
461
462 free(defattr);
463 return LTTNG_OK;
464
465 error_free_chan:
466 /*
467 * No need to remove the channel from the hash table because at this point
468 * it was not added hence the direct call and no call_rcu().
469 */
470 trace_ust_destroy_channel(uchan);
471 error:
472 free(defattr);
473 return ret;
474 }
475
476 /*
477 * Disable UST channel for session and domain.
478 */
479 int channel_ust_disable(struct ltt_ust_session *usess,
480 struct ltt_ust_channel *uchan)
481 {
482 int ret = LTTNG_OK;
483
484 assert(usess);
485 assert(uchan);
486
487 /* Already disabled */
488 if (uchan->enabled == 0) {
489 DBG2("Channel UST %s already disabled", uchan->name);
490 goto end;
491 }
492
493 DBG2("Channel %s being disabled in UST global domain", uchan->name);
494 /* Disable channel for global domain */
495 ret = ust_app_disable_channel_glb(usess, uchan);
496 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
497 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
498 goto error;
499 }
500
501 uchan->enabled = 0;
502
503 DBG2("Channel %s disabled successfully", uchan->name);
504
505 return LTTNG_OK;
506
507 end:
508 error:
509 return ret;
510 }
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