Remove useless zero initialization
[lttng-tools.git] / ltt-sessiond / kernel-ctl.c
CommitLineData
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1/*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
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
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
8c0faa1d 19#define _GNU_SOURCE
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20#include <errno.h>
21#include <stdlib.h>
22#include <stdio.h>
f34daff7 23#include <string.h>
8c0faa1d 24#include <unistd.h>
20fe2104 25
8c0faa1d 26#include "lttngerr.h"
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27#include "ltt-sessiond.h"
28#include "libkernelctl.h"
29#include "kernel-ctl.h"
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30
31/*
32 * kernel_create_session
33 *
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34 * Create a new kernel session, register it to the kernel tracer and add it to
35 * the session daemon session.
20fe2104 36 */
8c0faa1d 37int kernel_create_session(struct ltt_session *session, int tracer_fd)
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38{
39 int ret;
40 struct ltt_kernel_session *lks;
41
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42 /* Allocate data structure */
43 lks = trace_create_kernel_session();
20fe2104 44 if (lks == NULL) {
54012638 45 ret = -1;
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46 goto error;
47 }
48
54012638 49 /* Kernel tracer session creation */
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50 ret = kernctl_create_session(tracer_fd);
51 if (ret < 0) {
54012638 52 perror("ioctl kernel create session");
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53 goto error;
54 }
55
20fe2104 56 lks->fd = ret;
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57 session->kernel_session = lks;
58 session->kern_session_count++;
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59
60 DBG("Kernel session created (fd: %d)", lks->fd);
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61
62 return 0;
63
64error:
65 return ret;
66}
67
68/*
69 * kernel_create_channel
70 *
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71 * Create a kernel channel, register it to the kernel tracer and add it to the
72 * kernel session.
20fe2104 73 */
8c0faa1d 74int kernel_create_channel(struct ltt_kernel_session *session)
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75{
76 int ret;
77 struct ltt_kernel_channel *lkc;
20fe2104 78
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79 /* Allocate kernel channel */
80 lkc = trace_create_kernel_channel();
81 if (lkc == NULL) {
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82 goto error;
83 }
84
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85 /* Kernel tracer channel creation */
86 ret = kernctl_create_channel(session->fd, lkc->channel);
20fe2104 87 if (ret < 0) {
54012638 88 perror("ioctl kernel create channel");
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89 goto error;
90 }
91
54012638 92 /* Setup the channel fd */
20fe2104 93 lkc->fd = ret;
54012638 94 /* Add channel to session */
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95 cds_list_add(&lkc->list, &session->channel_list.head);
96 session->channel_count++;
20fe2104 97
54012638 98 DBG("Kernel channel created (fd: %d and path: %s)", lkc->fd, lkc->pathname);
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99
100 return 0;
101
102error:
54012638 103 return -1;
20fe2104 104}
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105
106/*
107 * kernel_enable_event
108 *
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109 * Create a kernel event, enable it to the kernel tracer and add it to the
110 * channel event list of the kernel session.
f34daff7 111 */
8c0faa1d 112int kernel_enable_event(struct ltt_kernel_session *session, char *name)
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113{
114 int ret;
8c0faa1d 115 struct ltt_kernel_channel *chan;
f34daff7 116 struct ltt_kernel_event *event;
f34daff7 117
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118 event = trace_create_kernel_event(name, LTTNG_KERNEL_TRACEPOINTS);
119 if (event == NULL) {
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120 goto error;
121 }
122
8c0faa1d 123 cds_list_for_each_entry(chan, &session->channel_list.head, list) {
54012638 124 ret = kernctl_create_event(chan->fd, event->event);
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125 if (ret < 0) {
126 goto error;
127 }
f34daff7 128
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129 event->fd = ret;
130 /* Add event to event list */
131 cds_list_add(&event->list, &chan->events_list.head);
132 DBG("Event %s enabled (fd: %d)", name, event->fd);
133 }
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134
135 return 0;
136
137error:
54012638 138 return -1;
f34daff7 139}
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140
141/*
142 * kernel_open_metadata
143 *
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144 * Create kernel metadata, open from the kernel tracer and add it to the
145 * kernel session.
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146 */
147int kernel_open_metadata(struct ltt_kernel_session *session)
148{
149 int ret;
150 struct ltt_kernel_metadata *lkm;
aaf26714 151
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152 /* Allocate kernel metadata */
153 lkm = trace_create_kernel_metadata();
154 if (lkm == NULL) {
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155 goto error;
156 }
157
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158 /* Kernel tracer metadata creation */
159 ret = kernctl_open_metadata(session->fd, lkm->conf);
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160 if (ret < 0) {
161 goto error;
162 }
163
8c0faa1d 164 lkm->fd = ret;
aaf26714 165 session->metadata = lkm;
8c0faa1d 166
54012638 167 DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
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168
169 return 0;
170
171error:
54012638 172 return -1;
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173}
174
175/*
176 * kernel_start_session
177 *
178 * Start tracing session.
179 */
180int kernel_start_session(struct ltt_kernel_session *session)
181{
182 int ret;
183
184 ret = kernctl_start_session(session->fd);
185 if (ret < 0) {
186 goto error;
187 }
188
189 DBG("Kernel session started");
190
191 return 0;
192
193error:
194 return ret;
195}
196
197/*
198 * kernel_stop_session
199 *
200 * Stop tracing session.
201 */
202int kernel_stop_session(struct ltt_kernel_session *session)
203{
204 int ret;
205
206 ret = kernctl_stop_session(session->fd);
207 if (ret < 0) {
208 goto error;
209 }
210
211 DBG("Kernel session stopped");
212
213 return 0;
214
215error:
216 return ret;
217}
218
219/*
220 * kernel_create_channel_stream
221 *
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222 * Create a stream for a channel, register it to the kernel tracer and add it
223 * to the stream list of the channel.
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224 *
225 * Return the number of created stream. Else, a negative value.
226 */
227int kernel_create_channel_stream(struct ltt_kernel_channel *channel)
228{
229 int ret;
230 struct ltt_kernel_stream *lks;
231
232 while ((ret = kernctl_create_stream(channel->fd)) > 0) {
54012638 233 lks = trace_create_kernel_stream();
8c0faa1d 234 if (lks == NULL) {
54012638 235 close(ret);
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236 goto error;
237 }
238
239 lks->fd = ret;
240 ret = asprintf(&lks->pathname, "%s/trace_%d",
241 channel->pathname, channel->stream_count);
242 if (ret < 0) {
243 perror("asprintf kernel create stream");
244 goto error;
245 }
8c0faa1d 246
54012638 247 /* Add stream to channe stream list */
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248 cds_list_add(&lks->list, &channel->stream_list.head);
249 channel->stream_count++;
8c0faa1d 250
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251 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
252 channel->stream_count, lks->fd, lks->state, lks->pathname);
253 }
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254
255 return channel->stream_count;
256
257error:
54012638 258 return -1;
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259}
260
261/*
262 * kernel_create_metadata_stream
263 *
54012638 264 * Create the metadata stream and set it to the kernel session.
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265 */
266int kernel_create_metadata_stream(struct ltt_kernel_session *session)
267{
268 int ret;
269
270 ret = kernctl_create_stream(session->metadata->fd);
271 if (ret < 0) {
272 perror("kernel create metadata stream");
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273 goto error;
274 }
275
276 DBG("Kernel metadata stream created (fd: %d)", ret);
277 session->metadata_stream_fd = ret;
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278
279 return 0;
280
281error:
54012638 282 return -1;
aaf26714 283}
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