7ebe4b16eb49a467dda2420892685283eaf3375b
[lttng-tools.git] / src / bin / lttng-sessiond / channel.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #define _GNU_SOURCE
19 #include <string.h>
20 #include <unistd.h>
21
22 #include <common/common.h>
23 #include <common/defaults.h>
24 #include <common/sessiond-comm/sessiond-comm.h>
25
26 #include "channel.h"
27 #include "kernel.h"
28 #include "ust-ctl.h"
29 #include "utils.h"
30 #include "ust-app.h"
31
32 /*
33 * Return allocated channel attributes.
34 */
35 struct lttng_channel *channel_new_default_attr(int dom)
36 {
37 struct lttng_channel *chan;
38
39 chan = zmalloc(sizeof(struct lttng_channel));
40 if (chan == NULL) {
41 PERROR("zmalloc channel init");
42 goto error_alloc;
43 }
44
45 if (snprintf(chan->name, sizeof(chan->name), "%s",
46 DEFAULT_CHANNEL_NAME) < 0) {
47 PERROR("snprintf default channel name");
48 goto error;
49 }
50
51 chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
52 chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
53 chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
54
55 switch (dom) {
56 case LTTNG_DOMAIN_KERNEL:
57 chan->attr.subbuf_size =
58 default_get_kernel_channel_subbuf_size();
59 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
60 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
61 break;
62 case LTTNG_DOMAIN_UST:
63 #if 0
64 case LTTNG_DOMAIN_UST_PID:
65 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
66 case LTTNG_DOMAIN_UST_EXEC_NAME:
67 #endif
68 chan->attr.subbuf_size = default_get_ust_channel_subbuf_size();
69 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
70 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
71 break;
72 default:
73 goto error; /* Not implemented */
74 }
75
76 return chan;
77
78 error:
79 free(chan);
80 error_alloc:
81 return NULL;
82 }
83
84 /*
85 * Disable kernel channel of the kernel session.
86 */
87 int channel_kernel_disable(struct ltt_kernel_session *ksession,
88 char *channel_name)
89 {
90 int ret;
91 struct ltt_kernel_channel *kchan;
92
93 assert(ksession);
94 assert(channel_name);
95
96 kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
97 if (kchan == NULL) {
98 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
99 goto error;
100 }
101
102 /* Only if channel is enabled disable it. */
103 if (kchan->enabled == 1) {
104 ret = kernel_disable_channel(kchan);
105 if (ret < 0 && ret != -EEXIST) {
106 ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
107 goto error;
108 }
109 }
110
111 ret = LTTNG_OK;
112
113 error:
114 return ret;
115 }
116
117 /*
118 * Enable kernel channel of the kernel session.
119 */
120 int channel_kernel_enable(struct ltt_kernel_session *ksession,
121 struct ltt_kernel_channel *kchan)
122 {
123 int ret;
124
125 assert(ksession);
126 assert(kchan);
127
128 if (kchan->enabled == 0) {
129 ret = kernel_enable_channel(kchan);
130 if (ret < 0) {
131 ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
132 goto error;
133 }
134 } else {
135 ret = LTTNG_ERR_KERN_CHAN_EXIST;
136 goto error;
137 }
138
139 ret = LTTNG_OK;
140
141 error:
142 return ret;
143 }
144
145 /*
146 * Create kernel channel of the kernel session and notify kernel thread.
147 */
148 int channel_kernel_create(struct ltt_kernel_session *ksession,
149 struct lttng_channel *attr, int kernel_pipe)
150 {
151 int ret;
152 struct lttng_channel *defattr = NULL;
153
154 assert(ksession);
155
156 /* Creating channel attributes if needed */
157 if (attr == NULL) {
158 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
159 if (defattr == NULL) {
160 ret = LTTNG_ERR_FATAL;
161 goto error;
162 }
163 attr = defattr;
164 }
165
166 /* Channel not found, creating it */
167 ret = kernel_create_channel(ksession, attr);
168 if (ret < 0) {
169 ret = LTTNG_ERR_KERN_CHAN_FAIL;
170 goto error;
171 }
172
173 /* Notify kernel thread that there is a new channel */
174 ret = notify_thread_pipe(kernel_pipe);
175 if (ret < 0) {
176 ret = LTTNG_ERR_FATAL;
177 goto error;
178 }
179
180 ret = LTTNG_OK;
181 error:
182 free(defattr);
183 return ret;
184 }
185
186 /*
187 * Enable UST channel for session and domain.
188 */
189 int channel_ust_enable(struct ltt_ust_session *usess, int domain,
190 struct ltt_ust_channel *uchan)
191 {
192 int ret = LTTNG_OK;
193
194 assert(usess);
195 assert(uchan);
196
197 /* If already enabled, everything is OK */
198 if (uchan->enabled) {
199 DBG3("Channel %s already enabled. Skipping", uchan->name);
200 ret = LTTNG_ERR_UST_CHAN_EXIST;
201 goto end;
202 }
203
204 switch (domain) {
205 case LTTNG_DOMAIN_UST:
206 DBG2("Channel %s being enabled in UST global domain", uchan->name);
207
208 /*
209 * Enable channel for UST global domain on all applications. Ignore
210 * return value here since whatever error we got, it means that the
211 * channel was not created on one or many registered applications and
212 * we can not report this to the user yet. However, at this stage, the
213 * channel was successfully created on the session daemon side so the
214 * enable-channel command is a success.
215 */
216 (void) ust_app_create_channel_glb(usess, uchan);
217 break;
218 #if 0
219 case LTTNG_DOMAIN_UST_PID:
220 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
221 case LTTNG_DOMAIN_UST_EXEC_NAME:
222 #endif
223 default:
224 ret = LTTNG_ERR_UND;
225 goto error;
226 }
227
228 uchan->enabled = 1;
229 DBG2("Channel %s enabled successfully", uchan->name);
230
231 end:
232 error:
233 return ret;
234 }
235
236 /*
237 * Create UST channel for session and domain.
238 */
239 int channel_ust_create(struct ltt_ust_session *usess, int domain,
240 struct lttng_channel *attr)
241 {
242 int ret = LTTNG_OK;
243 struct ltt_ust_channel *uchan = NULL;
244 struct lttng_channel *defattr = NULL;
245
246 assert(usess);
247
248 /* Creating channel attributes if needed */
249 if (attr == NULL) {
250 defattr = channel_new_default_attr(domain);
251 if (defattr == NULL) {
252 ret = LTTNG_ERR_FATAL;
253 goto error;
254 }
255 attr = defattr;
256 }
257
258 if (attr->attr.subbuf_size < DEFAULT_UST_CHANNEL_SUBBUF_SIZE) {
259 ret = LTTNG_ERR_INVALID;
260 goto error;
261 }
262
263 /*
264 * Validate UST buffer size and number of buffers: must both be power of 2
265 * and nonzero. We validate right here for UST, because applications will
266 * not report the error to the user (unlike kernel tracing).
267 */
268 if (!attr->attr.subbuf_size ||
269 (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
270 ret = LTTNG_ERR_INVALID;
271 goto error;
272 }
273
274 if (!attr->attr.num_subbuf ||
275 (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
276 ret = LTTNG_ERR_INVALID;
277 goto error;
278 }
279
280 if (attr->attr.output != LTTNG_EVENT_MMAP) {
281 ret = LTTNG_ERR_NOT_SUPPORTED;
282 goto error;
283 }
284
285 /* Create UST channel */
286 uchan = trace_ust_create_channel(attr, usess->pathname);
287 if (uchan == NULL) {
288 ret = LTTNG_ERR_FATAL;
289 goto error;
290 }
291 uchan->enabled = 1;
292
293 switch (domain) {
294 case LTTNG_DOMAIN_UST:
295 DBG2("Channel %s being created in UST global domain", uchan->name);
296
297 /* Enable channel for global domain */
298 ret = ust_app_create_channel_glb(usess, uchan);
299 break;
300 #if 0
301 case LTTNG_DOMAIN_UST_PID:
302 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
303 case LTTNG_DOMAIN_UST_EXEC_NAME:
304 #endif
305 default:
306 ret = LTTNG_ERR_UND;
307 goto error_free_chan;
308 }
309
310 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
311 ret = LTTNG_ERR_UST_CHAN_FAIL;
312 goto error_free_chan;
313 }
314
315 /* Adding the channel to the channel hash table. */
316 rcu_read_lock();
317 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
318 rcu_read_unlock();
319
320 DBG2("Channel %s created successfully", uchan->name);
321
322 free(defattr);
323 return LTTNG_OK;
324
325 error_free_chan:
326 /*
327 * No need to remove the channel from the hash table because at this point
328 * it was not added hence the direct call and no call_rcu().
329 */
330 trace_ust_destroy_channel(uchan);
331 error:
332 free(defattr);
333 return ret;
334 }
335
336 /*
337 * Disable UST channel for session and domain.
338 */
339 int channel_ust_disable(struct ltt_ust_session *usess, int domain,
340 struct ltt_ust_channel *uchan)
341 {
342 int ret = LTTNG_OK;
343
344 assert(usess);
345 assert(uchan);
346
347 /* Already disabled */
348 if (uchan->enabled == 0) {
349 DBG2("Channel UST %s already disabled", uchan->name);
350 goto end;
351 }
352
353 /* Get the right channel's hashtable */
354 switch (domain) {
355 case LTTNG_DOMAIN_UST:
356 DBG2("Channel %s being disabled in UST global domain", uchan->name);
357 /* Disable channel for global domain */
358 ret = ust_app_disable_channel_glb(usess, uchan);
359 break;
360 #if 0
361 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
362 case LTTNG_DOMAIN_UST_EXEC_NAME:
363 case LTTNG_DOMAIN_UST_PID:
364 #endif
365 default:
366 ret = LTTNG_ERR_UND;
367 goto error;
368 }
369
370 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
371 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
372 goto error;
373 }
374
375 uchan->enabled = 0;
376
377 DBG2("Channel %s disabled successfully", uchan->name);
378
379 return LTTNG_OK;
380
381 end:
382 error:
383 return ret;
384 }
This page took 0.038222 seconds and 3 git commands to generate.