3925c6ba5afc8e17f193dea1b497c7291a5ac52f
[lttng-tools.git] / ltt-sessiond / kernel-ctl.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
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
19 #define _GNU_SOURCE
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <stdlib.h>
23 #include <stdio.h>
24 #include <string.h>
25 #include <unistd.h>
26
27 #include "lttngerr.h"
28 #include "ltt-sessiond.h"
29 #include "libkernelctl.h"
30 #include "kernel-ctl.h"
31
32 /*
33 * kernel_create_session
34 *
35 * Create a new kernel session, register it to the kernel tracer and add it to
36 * the session daemon session.
37 */
38 int kernel_create_session(struct ltt_session *session, int tracer_fd)
39 {
40 int ret;
41 struct ltt_kernel_session *lks;
42
43 /* Allocate data structure */
44 lks = trace_create_kernel_session();
45 if (lks == NULL) {
46 ret = -1;
47 goto error;
48 }
49
50 /* Kernel tracer session creation */
51 ret = kernctl_create_session(tracer_fd);
52 if (ret < 0) {
53 perror("ioctl kernel create session");
54 goto error;
55 }
56
57 lks->fd = ret;
58 /* Prevent fd duplication after execlp() */
59 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
60 if (ret < 0) {
61 perror("fcntl session fd");
62 }
63
64 lks->kconsumer_fds_sent = 0;
65 session->kernel_session = lks;
66 session->kern_session_count++;
67
68 DBG("Kernel session created (fd: %d)", lks->fd);
69
70 return 0;
71
72 error:
73 return ret;
74 }
75
76 /*
77 * kernel_create_channel
78 *
79 * Create a kernel channel, register it to the kernel tracer and add it to the
80 * kernel session.
81 */
82 int kernel_create_channel(struct ltt_kernel_session *session, struct lttng_channel *chan)
83 {
84 int ret;
85 struct ltt_kernel_channel *lkc;
86
87 /* Allocate kernel channel */
88 lkc = trace_create_kernel_channel(chan);
89 if (lkc == NULL) {
90 goto error;
91 }
92
93 /* Kernel tracer channel creation */
94 ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
95 if (ret < 0) {
96 perror("ioctl kernel create channel");
97 goto error;
98 }
99
100 /* Setup the channel fd */
101 lkc->fd = ret;
102 /* Prevent fd duplication after execlp() */
103 ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
104 if (ret < 0) {
105 perror("fcntl session fd");
106 }
107
108 /* Add channel to session */
109 cds_list_add(&lkc->list, &session->channel_list.head);
110 session->channel_count++;
111
112 DBG("Kernel channel %s created (fd: %d and path: %s)",
113 lkc->channel->name, lkc->fd, lkc->pathname);
114
115 return 0;
116
117 error:
118 return -1;
119 }
120
121 /*
122 * kernel_create_event
123 *
124 * Create a kernel event, enable it to the kernel tracer and add it to the
125 * channel event list of the kernel session.
126 */
127 int kernel_create_event(struct ltt_kernel_channel *channel, struct lttng_event *ev)
128 {
129 int ret;
130 struct ltt_kernel_event *event;
131
132 event = trace_create_kernel_event(ev);
133 if (event == NULL) {
134 goto error;
135 }
136
137 ret = kernctl_create_event(channel->fd, event->event);
138 if (ret < 0) {
139 ERR("Unable to enable event %s for channel %s", ev->name, channel->channel->name);
140 goto error;
141 }
142
143 event->fd = ret;
144 /* Prevent fd duplication after execlp() */
145 ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
146 if (ret < 0) {
147 perror("fcntl session fd");
148 }
149
150 /* Add event to event list */
151 cds_list_add(&event->list, &channel->events_list.head);
152 DBG("Event %s enabled (fd: %d)", ev->name, event->fd);
153
154 return 0;
155
156 error:
157 return -1;
158 }
159
160 /*
161 * kernel_open_metadata
162 *
163 * Create kernel metadata, open from the kernel tracer and add it to the
164 * kernel session.
165 */
166 int kernel_open_metadata(struct ltt_kernel_session *session)
167 {
168 int ret;
169 struct ltt_kernel_metadata *lkm;
170
171 /* Allocate kernel metadata */
172 lkm = trace_create_kernel_metadata();
173 if (lkm == NULL) {
174 goto error;
175 }
176
177 /* Kernel tracer metadata creation */
178 ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
179 if (ret < 0) {
180 goto error;
181 }
182
183 lkm->fd = ret;
184 /* Prevent fd duplication after execlp() */
185 ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
186 if (ret < 0) {
187 perror("fcntl session fd");
188 }
189
190 session->metadata = lkm;
191
192 DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
193
194 return 0;
195
196 error:
197 return -1;
198 }
199
200 /*
201 * kernel_start_session
202 *
203 * Start tracing session.
204 */
205 int kernel_start_session(struct ltt_kernel_session *session)
206 {
207 int ret;
208
209 ret = kernctl_start_session(session->fd);
210 if (ret < 0) {
211 perror("ioctl start session");
212 goto error;
213 }
214
215 DBG("Kernel session started");
216
217 return 0;
218
219 error:
220 return ret;
221 }
222
223 /*
224 * kernel_wait_quiescent
225 *
226 * Make a kernel wait to make sure in-flight probe have completed.
227 */
228 void kernel_wait_quiescent(int fd)
229 {
230 int ret;
231
232 DBG("Kernel quiescent wait on %d", fd);
233
234 ret = kernctl_wait_quiescent(fd);
235 if (ret < 0) {
236 perror("wait quiescent ioctl");
237 ERR("Kernel quiescent wait failed");
238 }
239 }
240
241 /*
242 * kernel_metadata_flush_buffer
243 *
244 * Force flush buffer of metadata.
245 */
246 int kernel_metadata_flush_buffer(int fd)
247 {
248 int ret;
249
250 ret = kernctl_buffer_flush(fd);
251 if (ret < 0) {
252 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
253 }
254
255 return 0;
256 }
257
258 /*
259 * kernel_flush_buffer
260 *
261 * Force flush buffer for channel.
262 */
263 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
264 {
265 int ret;
266 struct ltt_kernel_stream *stream;
267
268 DBG("Flush buffer for channel %s", channel->channel->name);
269
270 cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
271 DBG("Flushing channel stream %d", stream->fd);
272 ret = kernctl_buffer_flush(stream->fd);
273 if (ret < 0) {
274 perror("ioctl");
275 ERR("Fail to flush buffer for stream %d (ret: %d)",
276 stream->fd, ret);
277 }
278 }
279
280 return 0;
281 }
282
283 /*
284 * kernel_stop_session
285 *
286 * Stop tracing session.
287 */
288 int kernel_stop_session(struct ltt_kernel_session *session)
289 {
290 int ret;
291
292 ret = kernctl_stop_session(session->fd);
293 if (ret < 0) {
294 goto error;
295 }
296
297 DBG("Kernel session stopped");
298
299 return 0;
300
301 error:
302 return ret;
303 }
304
305 /*
306 * kernel_open_channel_stream
307 *
308 * Open stream of channel, register it to the kernel tracer and add it
309 * to the stream list of the channel.
310 *
311 * Return the number of created stream. Else, a negative value.
312 */
313 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
314 {
315 int ret;
316 struct ltt_kernel_stream *lks;
317
318 while ((ret = kernctl_create_stream(channel->fd)) > 0) {
319 lks = trace_create_kernel_stream();
320 if (lks == NULL) {
321 close(ret);
322 goto error;
323 }
324
325 lks->fd = ret;
326 /* Prevent fd duplication after execlp() */
327 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
328 if (ret < 0) {
329 perror("fcntl session fd");
330 }
331
332 ret = asprintf(&lks->pathname, "%s/trace_%d",
333 channel->pathname, channel->stream_count);
334 if (ret < 0) {
335 perror("asprintf kernel create stream");
336 goto error;
337 }
338
339 /* Add stream to channe stream list */
340 cds_list_add(&lks->list, &channel->stream_list.head);
341 channel->stream_count++;
342
343 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
344 channel->stream_count, lks->fd, lks->state, lks->pathname);
345 }
346
347 return channel->stream_count;
348
349 error:
350 return -1;
351 }
352
353 /*
354 * kernel_open_metadata_stream
355 *
356 * Open the metadata stream and set it to the kernel session.
357 */
358 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
359 {
360 int ret;
361
362 ret = kernctl_create_stream(session->metadata->fd);
363 if (ret < 0) {
364 perror("kernel create metadata stream");
365 goto error;
366 }
367
368 DBG("Kernel metadata stream created (fd: %d)", ret);
369 session->metadata_stream_fd = ret;
370 /* Prevent fd duplication after execlp() */
371 ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
372 if (ret < 0) {
373 perror("fcntl session fd");
374 }
375
376 return 0;
377
378 error:
379 return -1;
380 }
381
382 /*
383 * kernel_list_events
384 *
385 * Get the event list from the kernel tracer and return that list in the CTF
386 * format.
387 */
388 ssize_t kernel_list_events(int tracer_fd, char **list)
389 {
390 int fd;
391 char *buf, *line = NULL;
392 size_t nb, nbmem, total = 0;
393 ssize_t size;
394 FILE *fp;
395
396 fd = kernctl_tracepoint_list(tracer_fd);
397 if (fd < 0) {
398 perror("kernel tracepoint list");
399 goto error;
400 }
401
402 fp = fdopen(fd, "r");
403 if (fp == NULL) {
404 perror("kernel tracepoint list fdopen");
405 goto error;
406 }
407
408 /*
409 * Init memory size counter
410 * See kernel-ctl.h for explanation of this value
411 */
412 nbmem = KERNEL_EVENT_LIST_SIZE;
413 buf = malloc(nbmem);
414
415 while ((size = getline(&line, &nb, fp)) != -1) {
416 if (total + size > nbmem) {
417 DBG("Reallocating event list from %zd to %zd bytes", nbmem,
418 total + size + KERNEL_EVENT_LIST_SIZE);
419 /* Adding the default size again */
420 nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
421 buf = realloc(buf, nbmem);
422 if (buf == NULL) {
423 perror("realloc list events");
424 goto error;
425 }
426 }
427 memcpy(buf + total, line, size);
428 total += size;
429 }
430
431 *list = buf;
432
433 DBG("Kernel list events done");
434
435 return total;
436
437 error:
438 return -1;
439 }
This page took 0.064989 seconds and 3 git commands to generate.