ff2db69db7389976c0c1dd3bd891cf5fbc969620
[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 <inttypes.h>
20 #include <string.h>
21 #include <unistd.h>
22
23 #include <common/common.h>
24 #include <common/defaults.h>
25 #include <common/sessiond-comm/sessiond-comm.h>
26
27 #include "channel.h"
28 #include "kernel.h"
29 #include "ust-ctl.h"
30 #include "utils.h"
31 #include "ust-app.h"
32
33 /*
34 * Return allocated channel attributes.
35 */
36 struct lttng_channel *channel_new_default_attr(int dom)
37 {
38 struct lttng_channel *chan;
39
40 chan = zmalloc(sizeof(struct lttng_channel));
41 if (chan == NULL) {
42 PERROR("zmalloc channel init");
43 goto error_alloc;
44 }
45
46 if (snprintf(chan->name, sizeof(chan->name), "%s",
47 DEFAULT_CHANNEL_NAME) < 0) {
48 PERROR("snprintf default channel name");
49 goto error;
50 }
51
52 chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
53
54 switch (dom) {
55 case LTTNG_DOMAIN_KERNEL:
56 chan->attr.subbuf_size =
57 default_get_kernel_channel_subbuf_size();
58 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
59 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
60 chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
61 chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
62 break;
63 case LTTNG_DOMAIN_UST:
64 #if 0
65 case LTTNG_DOMAIN_UST_PID:
66 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
67 case LTTNG_DOMAIN_UST_EXEC_NAME:
68 #endif
69 chan->attr.subbuf_size = default_get_ust_channel_subbuf_size();
70 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
71 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
72 chan->attr.switch_timer_interval = DEFAULT_UST_CHANNEL_SWITCH_TIMER;
73 chan->attr.read_timer_interval = DEFAULT_UST_CHANNEL_READ_TIMER;
74 break;
75 default:
76 goto error; /* Not implemented */
77 }
78
79 return chan;
80
81 error:
82 free(chan);
83 error_alloc:
84 return NULL;
85 }
86
87 /*
88 * Disable kernel channel of the kernel session.
89 */
90 int channel_kernel_disable(struct ltt_kernel_session *ksession,
91 char *channel_name)
92 {
93 int ret;
94 struct ltt_kernel_channel *kchan;
95
96 assert(ksession);
97 assert(channel_name);
98
99 kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
100 if (kchan == NULL) {
101 ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
102 goto error;
103 }
104
105 /* Only if channel is enabled disable it. */
106 if (kchan->enabled == 1) {
107 ret = kernel_disable_channel(kchan);
108 if (ret < 0 && ret != -EEXIST) {
109 ret = LTTNG_ERR_KERN_CHAN_DISABLE_FAIL;
110 goto error;
111 }
112 }
113
114 ret = LTTNG_OK;
115
116 error:
117 return ret;
118 }
119
120 /*
121 * Enable kernel channel of the kernel session.
122 */
123 int channel_kernel_enable(struct ltt_kernel_session *ksession,
124 struct ltt_kernel_channel *kchan)
125 {
126 int ret;
127
128 assert(ksession);
129 assert(kchan);
130
131 if (kchan->enabled == 0) {
132 ret = kernel_enable_channel(kchan);
133 if (ret < 0) {
134 ret = LTTNG_ERR_KERN_CHAN_ENABLE_FAIL;
135 goto error;
136 }
137 } else {
138 ret = LTTNG_ERR_KERN_CHAN_EXIST;
139 goto error;
140 }
141
142 ret = LTTNG_OK;
143
144 error:
145 return ret;
146 }
147
148 /*
149 * Create kernel channel of the kernel session and notify kernel thread.
150 */
151 int channel_kernel_create(struct ltt_kernel_session *ksession,
152 struct lttng_channel *attr, int kernel_pipe)
153 {
154 int ret;
155 struct lttng_channel *defattr = NULL;
156
157 assert(ksession);
158
159 /* Creating channel attributes if needed */
160 if (attr == NULL) {
161 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
162 if (defattr == NULL) {
163 ret = LTTNG_ERR_FATAL;
164 goto error;
165 }
166 attr = defattr;
167 }
168
169 /* Channel not found, creating it */
170 ret = kernel_create_channel(ksession, attr);
171 if (ret < 0) {
172 ret = LTTNG_ERR_KERN_CHAN_FAIL;
173 goto error;
174 }
175
176 /* Notify kernel thread that there is a new channel */
177 ret = notify_thread_pipe(kernel_pipe);
178 if (ret < 0) {
179 ret = LTTNG_ERR_FATAL;
180 goto error;
181 }
182
183 ret = LTTNG_OK;
184 error:
185 free(defattr);
186 return ret;
187 }
188
189 /*
190 * Enable UST channel for session and domain.
191 */
192 int channel_ust_enable(struct ltt_ust_session *usess,
193 struct ltt_ust_channel *uchan)
194 {
195 int ret = LTTNG_OK;
196
197 assert(usess);
198 assert(uchan);
199
200 /* If already enabled, everything is OK */
201 if (uchan->enabled) {
202 DBG3("Channel %s already enabled. Skipping", uchan->name);
203 ret = LTTNG_ERR_UST_CHAN_EXIST;
204 goto end;
205 }
206
207 DBG2("Channel %s being enabled in UST domain", uchan->name);
208
209 /*
210 * Enable channel for UST global domain on all applications. Ignore return
211 * value here since whatever error we got, it means that the channel was
212 * not created on one or many registered applications and we can not report
213 * this to the user yet. However, at this stage, the channel was
214 * successfully created on the session daemon side so the enable-channel
215 * command is a success.
216 */
217 (void) ust_app_enable_channel_glb(usess, uchan);
218
219 uchan->enabled = 1;
220 DBG2("Channel %s enabled successfully", uchan->name);
221
222 end:
223 return ret;
224 }
225
226 /*
227 * Create UST channel for session and domain.
228 */
229 int channel_ust_create(struct ltt_ust_session *usess,
230 struct lttng_channel *attr, enum lttng_buffer_type type)
231 {
232 int ret = LTTNG_OK;
233 struct ltt_ust_channel *uchan = NULL;
234 struct lttng_channel *defattr = NULL;
235
236 assert(usess);
237
238 /* Creating channel attributes if needed */
239 if (attr == NULL) {
240 defattr = channel_new_default_attr(LTTNG_DOMAIN_UST);
241 if (defattr == NULL) {
242 ret = LTTNG_ERR_FATAL;
243 goto error;
244 }
245 attr = defattr;
246 }
247
248 if (attr->attr.subbuf_size < DEFAULT_UST_CHANNEL_SUBBUF_SIZE) {
249 ret = LTTNG_ERR_INVALID;
250 goto error;
251 }
252
253 /*
254 * Validate UST buffer size and number of buffers: must both be power of 2
255 * and nonzero. We validate right here for UST, because applications will
256 * not report the error to the user (unlike kernel tracing).
257 */
258 if (!attr->attr.subbuf_size ||
259 (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
260 ret = LTTNG_ERR_INVALID;
261 goto error;
262 }
263
264 if (!attr->attr.num_subbuf ||
265 (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
266 ret = LTTNG_ERR_INVALID;
267 goto error;
268 }
269
270 if (attr->attr.output != LTTNG_EVENT_MMAP) {
271 ret = LTTNG_ERR_NOT_SUPPORTED;
272 goto error;
273 }
274
275 /*
276 * The tracefile_size should not be < to the subbuf_size, otherwise
277 * we won't be able to write the packets on disk
278 */
279 if ((attr->attr.tracefile_size > 0) &&
280 (attr->attr.tracefile_size < attr->attr.subbuf_size)) {
281 ret = LTTNG_ERR_INVALID;
282 goto error;
283 }
284
285 /* Validate buffer type. */
286 switch (type) {
287 case LTTNG_BUFFER_PER_PID:
288 case LTTNG_BUFFER_PER_UID:
289 break;
290 default:
291 ret = LTTNG_ERR_BUFFER_NOT_SUPPORTED;
292 goto error;
293 }
294
295 /* Create UST channel */
296 uchan = trace_ust_create_channel(attr);
297 if (uchan == NULL) {
298 ret = LTTNG_ERR_FATAL;
299 goto error;
300 }
301 uchan->enabled = 1;
302 if (trace_ust_is_max_id(usess->used_channel_id)) {
303 ret = LTTNG_ERR_UST_CHAN_FAIL;
304 goto error;
305 }
306 uchan->id = trace_ust_get_next_chan_id(usess);
307
308 DBG2("Channel %s is being created for UST with buffer %d and id %" PRIu64,
309 uchan->name, type, uchan->id);
310
311 /* Flag session buffer type. */
312 if (!usess->buffer_type_changed) {
313 usess->buffer_type = type;
314 usess->buffer_type_changed = 1;
315 } else if (usess->buffer_type != type) {
316 /* Buffer type was already set. Refuse to create channel. */
317 ret = LTTNG_ERR_BUFFER_TYPE_MISMATCH;
318 goto error_free_chan;
319 }
320
321 /* Enable channel for global domain */
322 ret = ust_app_create_channel_glb(usess, uchan);
323 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
324 ret = LTTNG_ERR_UST_CHAN_FAIL;
325 goto error_free_chan;
326 }
327
328 /* Adding the channel to the channel hash table. */
329 rcu_read_lock();
330 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
331 rcu_read_unlock();
332
333 DBG2("Channel %s created successfully", uchan->name);
334
335 free(defattr);
336 return LTTNG_OK;
337
338 error_free_chan:
339 /*
340 * No need to remove the channel from the hash table because at this point
341 * it was not added hence the direct call and no call_rcu().
342 */
343 trace_ust_destroy_channel(uchan);
344 error:
345 free(defattr);
346 return ret;
347 }
348
349 /*
350 * Disable UST channel for session and domain.
351 */
352 int channel_ust_disable(struct ltt_ust_session *usess,
353 struct ltt_ust_channel *uchan)
354 {
355 int ret = LTTNG_OK;
356
357 assert(usess);
358 assert(uchan);
359
360 /* Already disabled */
361 if (uchan->enabled == 0) {
362 DBG2("Channel UST %s already disabled", uchan->name);
363 goto end;
364 }
365
366 DBG2("Channel %s being disabled in UST global domain", uchan->name);
367 /* Disable channel for global domain */
368 ret = ust_app_disable_channel_glb(usess, uchan);
369 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
370 ret = LTTNG_ERR_UST_CHAN_DISABLE_FAIL;
371 goto error;
372 }
373
374 uchan->enabled = 0;
375
376 DBG2("Channel %s disabled successfully", uchan->name);
377
378 return LTTNG_OK;
379
380 end:
381 error:
382 return ret;
383 }
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