b5202fe6abe0807a35088e5b88ef8cd82e0779ce
[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 it
5 * under the terms of the GNU General Public License as published by the Free
6 * Software Foundation; only version 2 of the License.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15 * Place - Suite 330, Boston, MA 02111-1307, 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 = DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE;
58 chan->attr.num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
59 chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
60 break;
61 case LTTNG_DOMAIN_UST:
62 case LTTNG_DOMAIN_UST_PID:
63 chan->attr.subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
64 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
65 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
66 break;
67 default:
68 goto error; /* Not implemented */
69 }
70
71 return chan;
72
73 error:
74 free(chan);
75 error_alloc:
76 return NULL;
77 }
78
79 /*
80 * Disable kernel channel of the kernel session.
81 */
82 int channel_kernel_disable(struct ltt_kernel_session *ksession,
83 char *channel_name)
84 {
85 int ret;
86 struct ltt_kernel_channel *kchan;
87
88 kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
89 if (kchan == NULL) {
90 ret = LTTCOMM_KERN_CHAN_NOT_FOUND;
91 goto error;
92 } else if (kchan->enabled == 1) {
93 ret = kernel_disable_channel(kchan);
94 if (ret < 0 && ret != -EEXIST) {
95 ret = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
96 goto error;
97 }
98 }
99
100 ret = LTTCOMM_OK;
101
102 error:
103 return ret;
104 }
105
106 /*
107 * Enable kernel channel of the kernel session.
108 */
109 int channel_kernel_enable(struct ltt_kernel_session *ksession,
110 struct ltt_kernel_channel *kchan)
111 {
112 int ret;
113
114 if (kchan->enabled == 0) {
115 ret = kernel_enable_channel(kchan);
116 if (ret < 0) {
117 ret = LTTCOMM_KERN_CHAN_ENABLE_FAIL;
118 goto error;
119 }
120 }
121
122 ret = LTTCOMM_OK;
123
124 error:
125 return ret;
126 }
127
128 /*
129 * Create kernel channel of the kernel session and notify kernel thread.
130 */
131 int channel_kernel_create(struct ltt_kernel_session *ksession,
132 struct lttng_channel *attr, int kernel_pipe)
133 {
134 int ret;
135 struct lttng_channel *defattr = NULL;
136
137 /* Creating channel attributes if needed */
138 if (attr == NULL) {
139 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
140 if (defattr == NULL) {
141 ret = LTTCOMM_FATAL;
142 goto error;
143 }
144 attr = defattr;
145 }
146
147 /* Channel not found, creating it */
148 ret = kernel_create_channel(ksession, attr, ksession->trace_path);
149 if (ret < 0) {
150 ret = LTTCOMM_KERN_CHAN_FAIL;
151 goto error;
152 }
153
154 /* Notify kernel thread that there is a new channel */
155 ret = notify_thread_pipe(kernel_pipe);
156 if (ret < 0) {
157 ret = LTTCOMM_FATAL;
158 goto error;
159 }
160
161 ret = LTTCOMM_OK;
162 error:
163 free(defattr);
164 return ret;
165 }
166
167 /*
168 * Enable UST channel for session and domain.
169 */
170 int channel_ust_enable(struct ltt_ust_session *usess, int domain,
171 struct ltt_ust_channel *uchan)
172 {
173 int ret = LTTCOMM_OK;
174
175 /* If already enabled, everything is OK */
176 if (uchan->enabled) {
177 DBG3("Channel %s already enabled. Skipping", uchan->name);
178 goto end;
179 }
180
181 switch (domain) {
182 case LTTNG_DOMAIN_UST:
183 DBG2("Channel %s being enabled in UST global domain", uchan->name);
184 /* Enable channel for global domain */
185 ret = ust_app_enable_channel_glb(usess, uchan);
186 break;
187 case LTTNG_DOMAIN_UST_PID:
188 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
189 case LTTNG_DOMAIN_UST_EXEC_NAME:
190 ret = LTTCOMM_NOT_IMPLEMENTED;
191 goto error;
192 }
193
194 if (ret < 0) {
195 if (ret != -EEXIST) {
196 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
197 goto error;
198 } else {
199 ret = LTTCOMM_OK;
200 }
201 }
202
203 uchan->enabled = 1;
204 DBG2("Channel %s enabled successfully", uchan->name);
205
206 end:
207 error:
208 return ret;
209 }
210
211 /*
212 * Create UST channel for session and domain.
213 */
214 int channel_ust_create(struct ltt_ust_session *usess, int domain,
215 struct lttng_channel *attr)
216 {
217 int ret = LTTCOMM_OK;
218 struct ltt_ust_channel *uchan = NULL;
219 struct lttng_channel *defattr = NULL;
220
221 /* Creating channel attributes if needed */
222 if (attr == NULL) {
223 defattr = channel_new_default_attr(domain);
224 if (defattr == NULL) {
225 ret = LTTCOMM_FATAL;
226 goto error;
227 }
228 attr = defattr;
229 }
230
231 /* Create UST channel */
232 uchan = trace_ust_create_channel(attr, usess->pathname);
233 if (uchan == NULL) {
234 ret = LTTCOMM_FATAL;
235 goto error;
236 }
237 uchan->enabled = 1;
238
239 switch (domain) {
240 case LTTNG_DOMAIN_UST:
241 DBG2("Channel %s being created in UST global domain", uchan->name);
242
243 /* Enable channel for global domain */
244 ret = ust_app_create_channel_glb(usess, uchan);
245 break;
246 case LTTNG_DOMAIN_UST_PID:
247 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
248 case LTTNG_DOMAIN_UST_EXEC_NAME:
249 default:
250 ret = LTTCOMM_NOT_IMPLEMENTED;
251 goto error_free_chan;
252 }
253
254 if (ret < 0 && ret != -EEXIST) {
255 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
256 goto error_free_chan;
257 }
258
259 /* Adding the channel to the channel hash table. */
260 rcu_read_lock();
261 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
262 rcu_read_unlock();
263
264 DBG2("Channel %s created successfully", uchan->name);
265
266 free(defattr);
267 return LTTCOMM_OK;
268
269 error_free_chan:
270 /*
271 * No need to remove the channel from the hash table because at this point
272 * it was not added hence the direct call and no call_rcu().
273 */
274 trace_ust_destroy_channel(uchan);
275 error:
276 free(defattr);
277 return ret;
278 }
279
280 /*
281 * Disable UST channel for session and domain.
282 */
283 int channel_ust_disable(struct ltt_ust_session *usess, int domain,
284 struct ltt_ust_channel *uchan)
285 {
286 int ret = LTTCOMM_OK;
287
288 /* Already disabled */
289 if (uchan->enabled == 0) {
290 DBG2("Channel UST %s already disabled", uchan->name);
291 goto end;
292 }
293
294 /* Get the right channel's hashtable */
295 switch (domain) {
296 case LTTNG_DOMAIN_UST:
297 DBG2("Channel %s being disabled in UST global domain", uchan->name);
298 /* Disable channel for global domain */
299 ret = ust_app_disable_channel_glb(usess, uchan);
300 break;
301 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
302 case LTTNG_DOMAIN_UST_EXEC_NAME:
303 case LTTNG_DOMAIN_UST_PID:
304 ret = LTTCOMM_NOT_IMPLEMENTED;
305 goto error;
306 }
307
308 if (ret < 0 && ret != -EEXIST) {
309 ret = LTTCOMM_UST_DISABLE_FAIL;
310 goto error;
311 }
312
313 uchan->enabled = 0;
314
315 DBG2("Channel %s disabled successfully", uchan->name);
316
317 return LTTCOMM_OK;
318
319 end:
320 error:
321 return ret;
322 }
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