Fix possible error on close
[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;
f3ed775e 57 lks->kconsumer_fds_sent = 0;
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58 session->kernel_session = lks;
59 session->kern_session_count++;
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60
61 DBG("Kernel session created (fd: %d)", lks->fd);
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62
63 return 0;
64
65error:
66 return ret;
67}
68
69/*
70 * kernel_create_channel
71 *
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72 * Create a kernel channel, register it to the kernel tracer and add it to the
73 * kernel session.
20fe2104 74 */
f3ed775e 75int kernel_create_channel(struct ltt_kernel_session *session, struct lttng_channel *chan)
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76{
77 int ret;
78 struct ltt_kernel_channel *lkc;
20fe2104 79
54012638 80 /* Allocate kernel channel */
f3ed775e 81 lkc = trace_create_kernel_channel(chan);
54012638 82 if (lkc == NULL) {
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83 goto error;
84 }
85
54012638 86 /* Kernel tracer channel creation */
f3ed775e 87 ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
20fe2104 88 if (ret < 0) {
54012638 89 perror("ioctl kernel create channel");
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90 goto error;
91 }
92
54012638 93 /* Setup the channel fd */
20fe2104 94 lkc->fd = ret;
54012638 95 /* Add channel to session */
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96 cds_list_add(&lkc->list, &session->channel_list.head);
97 session->channel_count++;
20fe2104 98
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99 DBG("Kernel channel %s created (fd: %d and path: %s)",
100 lkc->channel->name, lkc->fd, lkc->pathname);
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101
102 return 0;
103
104error:
54012638 105 return -1;
20fe2104 106}
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107
108/*
f3ed775e 109 * kernel_create_event
f34daff7 110 *
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111 * Create a kernel event, enable it to the kernel tracer and add it to the
112 * channel event list of the kernel session.
f34daff7 113 */
f3ed775e 114int kernel_create_event(struct ltt_kernel_channel *channel, struct lttng_event *ev)
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115{
116 int ret;
117 struct ltt_kernel_event *event;
f34daff7 118
f3ed775e 119 event = trace_create_kernel_event(ev);
54012638 120 if (event == NULL) {
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121 goto error;
122 }
123
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124 ret = kernctl_create_event(channel->fd, event->event);
125 if (ret < 0) {
126 ERR("Unable to enable event %s for channel %s", ev->name, channel->channel->name);
127 goto error;
8c0faa1d 128 }
f34daff7 129
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130 event->fd = ret;
131 /* Add event to event list */
132 cds_list_add(&event->list, &channel->events_list.head);
133 DBG("Event %s enabled (fd: %d)", ev->name, event->fd);
134
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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
54012638 158 /* Kernel tracer metadata creation */
f3ed775e 159 ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
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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) {
f3ed775e 186 perror("ioctl start session");
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187 goto error;
188 }
189
190 DBG("Kernel session started");
191
192 return 0;
193
194error:
195 return ret;
196}
197
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198/*
199 * kernel_wait_quiescent
200 *
201 * Make a kernel wait to make sure in-flight probe have completed.
202 */
203void kernel_wait_quiescent(int fd)
204{
205 int ret;
206
207 DBG("Kernel quiescent wait on %d", fd);
208
209 ret = kernctl_wait_quiescent(fd);
210 if (ret < 0) {
211 perror("wait quiescent ioctl");
212 ERR("Kernel quiescent wait failed");
213 }
214}
215
216/*
217 * kernel_metadata_flush_buffer
218 *
219 * Force flush buffer of metadata.
220 */
221int kernel_metadata_flush_buffer(int fd)
222{
223 int ret;
224
225 ret = kernctl_buffer_flush(fd);
226 if (ret < 0) {
227 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
228 }
229
230 return 0;
231}
232
233/*
234 * kernel_flush_buffer
235 *
236 * Force flush buffer for channel.
237 */
238int kernel_flush_buffer(struct ltt_kernel_channel *channel)
239{
240 int ret;
241 struct ltt_kernel_stream *stream;
242
243 DBG("Flush buffer for channel %s", channel->channel->name);
244
245 cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
246 DBG("Flushing channel stream %d", stream->fd);
247 ret = kernctl_buffer_flush(stream->fd);
248 if (ret < 0) {
249 perror("ioctl");
250 ERR("Fail to flush buffer for stream %d (ret: %d)",
251 stream->fd, ret);
252 }
253 }
254
255 return 0;
256}
257
8c0faa1d
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258/*
259 * kernel_stop_session
260 *
261 * Stop tracing session.
262 */
263int kernel_stop_session(struct ltt_kernel_session *session)
264{
265 int ret;
266
267 ret = kernctl_stop_session(session->fd);
268 if (ret < 0) {
269 goto error;
270 }
271
272 DBG("Kernel session stopped");
273
274 return 0;
275
276error:
277 return ret;
278}
279
280/*
f3ed775e 281 * kernel_open_channel_stream
8c0faa1d 282 *
f3ed775e 283 * Open stream of channel, register it to the kernel tracer and add it
54012638 284 * to the stream list of the channel.
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285 *
286 * Return the number of created stream. Else, a negative value.
287 */
f3ed775e 288int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
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289{
290 int ret;
291 struct ltt_kernel_stream *lks;
292
293 while ((ret = kernctl_create_stream(channel->fd)) > 0) {
54012638 294 lks = trace_create_kernel_stream();
8c0faa1d 295 if (lks == NULL) {
54012638 296 close(ret);
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297 goto error;
298 }
299
300 lks->fd = ret;
301 ret = asprintf(&lks->pathname, "%s/trace_%d",
302 channel->pathname, channel->stream_count);
303 if (ret < 0) {
304 perror("asprintf kernel create stream");
305 goto error;
306 }
8c0faa1d 307
54012638 308 /* Add stream to channe stream list */
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309 cds_list_add(&lks->list, &channel->stream_list.head);
310 channel->stream_count++;
8c0faa1d 311
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312 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
313 channel->stream_count, lks->fd, lks->state, lks->pathname);
314 }
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315
316 return channel->stream_count;
317
318error:
54012638 319 return -1;
8c0faa1d
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320}
321
322/*
f3ed775e 323 * kernel_open_metadata_stream
8c0faa1d 324 *
f3ed775e 325 * Open the metadata stream and set it to the kernel session.
8c0faa1d 326 */
f3ed775e 327int kernel_open_metadata_stream(struct ltt_kernel_session *session)
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328{
329 int ret;
330
331 ret = kernctl_create_stream(session->metadata->fd);
332 if (ret < 0) {
333 perror("kernel create metadata stream");
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334 goto error;
335 }
336
337 DBG("Kernel metadata stream created (fd: %d)", ret);
338 session->metadata_stream_fd = ret;
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339
340 return 0;
341
342error:
54012638 343 return -1;
aaf26714 344}
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345
346/*
347 * kernel_list_events
348 *
349 * Get the event list from the kernel tracer and return that list in the CTF
350 * format.
351 */
352ssize_t kernel_list_events(int tracer_fd, char **list)
353{
354 int fd;
355 char *buf, *line = NULL;
356 size_t nb, nbmem, total = 0;
357 ssize_t size;
358 FILE *fp;
359
360 fd = kernctl_tracepoint_list(tracer_fd);
361 if (fd < 0) {
362 perror("kernel tracepoint list");
363 goto error;
364 }
365
366 fp = fdopen(fd, "r");
367 if (fp == NULL) {
368 perror("kernel tracepoint list fdopen");
369 goto error;
370 }
371
372 /*
373 * Init memory size counter
374 * See kernel-ctl.h for explanation of this value
375 */
376 nbmem = KERNEL_EVENT_LIST_SIZE;
377 buf = malloc(nbmem);
378
379 while ((size = getline(&line, &nb, fp)) != -1) {
380 if (total + size > nbmem) {
d686b40f 381 DBG("Reallocating event list from %zd to %zd bytes", nbmem,
2ef84c95
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382 total + size + KERNEL_EVENT_LIST_SIZE);
383 /* Adding the default size again */
384 nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
385 buf = realloc(buf, nbmem);
386 if (buf == NULL) {
387 perror("realloc list events");
388 goto error;
389 }
390 }
391 memcpy(buf + total, line, size);
392 total += size;
393 }
394
395 *list = buf;
396
397 DBG("Kernel list events done");
398
399 return total;
400
401error:
402 return -1;
403}
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