Fix multiple error handling for UST tracing
[lttng-tools.git] / 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 <lttng/lttng.h>
23 #include <lttng-ht.h>
24 #include <lttng-sessiond-comm.h>
25 #include <lttngerr.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 chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
54 chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
55
56 switch (dom) {
57 case LTTNG_DOMAIN_KERNEL:
58 chan->attr.subbuf_size = DEFAULT_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 case LTTNG_DOMAIN_UST_PID:
64 chan->attr.subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
65 chan->attr.num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
66 chan->attr.output = DEFAULT_UST_CHANNEL_OUTPUT;
67 break;
68 default:
69 goto error; /* Not implemented */
70 }
71
72 return chan;
73
74 error:
75 free(chan);
76 error_alloc:
77 return NULL;
78 }
79
80 /*
81 * Disable kernel channel of the kernel session.
82 */
83 int channel_kernel_disable(struct ltt_kernel_session *ksession,
84 char *channel_name)
85 {
86 int ret;
87 struct ltt_kernel_channel *kchan;
88
89 kchan = trace_kernel_get_channel_by_name(channel_name, ksession);
90 if (kchan == NULL) {
91 ret = LTTCOMM_KERN_CHAN_NOT_FOUND;
92 goto error;
93 } else if (kchan->enabled == 1) {
94 ret = kernel_disable_channel(kchan);
95 if (ret < 0 && ret != -EEXIST) {
96 ret = LTTCOMM_KERN_CHAN_DISABLE_FAIL;
97 goto error;
98 }
99 }
100
101 ret = LTTCOMM_OK;
102
103 error:
104 return ret;
105 }
106
107 /*
108 * Enable kernel channel of the kernel session.
109 */
110 int channel_kernel_enable(struct ltt_kernel_session *ksession,
111 struct ltt_kernel_channel *kchan)
112 {
113 int ret;
114
115 if (kchan->enabled == 0) {
116 ret = kernel_enable_channel(kchan);
117 if (ret < 0) {
118 ret = LTTCOMM_KERN_CHAN_ENABLE_FAIL;
119 goto error;
120 }
121 }
122
123 ret = LTTCOMM_OK;
124
125 error:
126 return ret;
127 }
128
129 /*
130 * Create kernel channel of the kernel session and notify kernel thread.
131 */
132 int channel_kernel_create(struct ltt_kernel_session *ksession,
133 struct lttng_channel *attr, int kernel_pipe)
134 {
135 int ret;
136 struct lttng_channel *defattr = NULL;
137
138 /* Creating channel attributes if needed */
139 if (attr == NULL) {
140 defattr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
141 if (defattr == NULL) {
142 ret = LTTCOMM_FATAL;
143 goto error;
144 }
145 attr = defattr;
146 }
147
148 /* Channel not found, creating it */
149 ret = kernel_create_channel(ksession, attr, ksession->trace_path);
150 if (ret < 0) {
151 ret = LTTCOMM_KERN_CHAN_FAIL;
152 goto error;
153 }
154
155 /* Notify kernel thread that there is a new channel */
156 ret = notify_thread_pipe(kernel_pipe);
157 if (ret < 0) {
158 ret = LTTCOMM_FATAL;
159 goto error;
160 }
161
162 ret = LTTCOMM_OK;
163 error:
164 free(defattr);
165 return ret;
166 }
167
168 /*
169 * Enable UST channel for session and domain.
170 */
171 int channel_ust_enable(struct ltt_ust_session *usess, int domain,
172 struct ltt_ust_channel *uchan)
173 {
174 int ret = LTTCOMM_OK;
175
176 /* If already enabled, everything is OK */
177 if (uchan->enabled) {
178 DBG3("Channel %s already enabled. Skipping", uchan->name);
179 goto end;
180 }
181
182 switch (domain) {
183 case LTTNG_DOMAIN_UST:
184 DBG2("Channel %s being enabled in UST global domain", uchan->name);
185 /* Enable channel for global domain */
186 ret = ust_app_enable_channel_glb(usess, uchan);
187 break;
188 case LTTNG_DOMAIN_UST_PID:
189 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
190 case LTTNG_DOMAIN_UST_EXEC_NAME:
191 ret = LTTCOMM_NOT_IMPLEMENTED;
192 goto error;
193 }
194
195 if (ret < 0) {
196 if (ret != -EEXIST) {
197 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
198 goto error;
199 } else {
200 ret = LTTCOMM_OK;
201 }
202 }
203
204 uchan->enabled = 1;
205 DBG2("Channel %s enabled successfully", uchan->name);
206
207 end:
208 error:
209 return ret;
210 }
211
212 /*
213 * Create UST channel for session and domain.
214 */
215 int channel_ust_create(struct ltt_ust_session *usess, int domain,
216 struct lttng_channel *attr)
217 {
218 int ret = LTTCOMM_OK;
219 struct ltt_ust_channel *uchan = NULL;
220 struct lttng_channel *defattr = NULL;
221
222 /* Creating channel attributes if needed */
223 if (attr == NULL) {
224 defattr = channel_new_default_attr(domain);
225 if (defattr == NULL) {
226 ret = LTTCOMM_FATAL;
227 goto error;
228 }
229 attr = defattr;
230 }
231
232 /* Create UST channel */
233 uchan = trace_ust_create_channel(attr, usess->pathname);
234 if (uchan == NULL) {
235 ret = LTTCOMM_FATAL;
236 goto error;
237 }
238 uchan->enabled = 1;
239
240 switch (domain) {
241 case LTTNG_DOMAIN_UST:
242 DBG2("Channel %s being created in UST global domain", uchan->name);
243
244 /* Enable channel for global domain */
245 ret = ust_app_create_channel_glb(usess, uchan);
246 break;
247 case LTTNG_DOMAIN_UST_PID:
248 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
249 case LTTNG_DOMAIN_UST_EXEC_NAME:
250 default:
251 ret = LTTCOMM_NOT_IMPLEMENTED;
252 goto error_free_chan;
253 }
254
255 if (ret < 0 && ret != -EEXIST) {
256 ret = LTTCOMM_UST_CHAN_ENABLE_FAIL;
257 goto error_free_chan;
258 }
259
260 /* Adding the channel to the channel hash table. */
261 rcu_read_lock();
262 lttng_ht_add_unique_str(usess->domain_global.channels, &uchan->node);
263 rcu_read_unlock();
264
265 DBG2("Channel %s created successfully", uchan->name);
266
267 free(defattr);
268 return LTTCOMM_OK;
269
270 error_free_chan:
271 /*
272 * No need to remove the channel from the hash table because at this point
273 * it was not added hence the direct call and no call_rcu().
274 */
275 trace_ust_destroy_channel(uchan);
276 error:
277 free(defattr);
278 return ret;
279 }
280
281 /*
282 * Disable UST channel for session and domain.
283 */
284 int channel_ust_disable(struct ltt_ust_session *usess, int domain,
285 struct ltt_ust_channel *uchan)
286 {
287 int ret = LTTCOMM_OK;
288
289 /* Already disabled */
290 if (uchan->enabled == 0) {
291 DBG2("Channel UST %s already disabled", uchan->name);
292 goto end;
293 }
294
295 /* Get the right channel's hashtable */
296 switch (domain) {
297 case LTTNG_DOMAIN_UST:
298 DBG2("Channel %s being disabled in UST global domain", uchan->name);
299 /* Disable channel for global domain */
300 ret = ust_app_disable_channel_glb(usess, uchan);
301 break;
302 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
303 case LTTNG_DOMAIN_UST_EXEC_NAME:
304 case LTTNG_DOMAIN_UST_PID:
305 ret = LTTCOMM_NOT_IMPLEMENTED;
306 goto error;
307 }
308
309 if (ret < 0 && ret != -EEXIST) {
310 ret = LTTCOMM_UST_DISABLE_FAIL;
311 goto error;
312 }
313
314 uchan->enabled = 0;
315
316 DBG2("Channel %s disabled successfully", uchan->name);
317
318 return LTTCOMM_OK;
319
320 end:
321 error:
322 return ret;
323 }
This page took 0.051263 seconds and 4 git commands to generate.