Create all trace directories and files with client user credentials
[lttng-tools.git] / liblttng-ustconsumer / lttng-ustconsumer.c
1 /*
2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; only version 2
8 * of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 */
19
20 #define _GNU_SOURCE
21 #include <assert.h>
22 #include <fcntl.h>
23 #include <poll.h>
24 #include <pthread.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <sys/mman.h>
28 #include <sys/socket.h>
29 #include <sys/types.h>
30 #include <unistd.h>
31
32 #include <lttng-sessiond-comm.h>
33 #include <lttng/lttng-ustconsumer.h>
34 #include <lttng/ust-ctl.h>
35 #include <lttngerr.h>
36
37 extern struct lttng_consumer_global_data consumer_data;
38 extern int consumer_poll_timeout;
39 extern volatile int consumer_quit;
40
41 /*
42 * Mmap the ring buffer, read it and write the data to the tracefile.
43 *
44 * Returns the number of bytes written
45 */
46 int lttng_ustconsumer_on_read_subbuffer_mmap(
47 struct lttng_consumer_local_data *ctx,
48 struct lttng_consumer_stream *stream, unsigned long len)
49 {
50 unsigned long mmap_offset;
51 long ret = 0;
52 off_t orig_offset = stream->out_fd_offset;
53 int outfd = stream->out_fd;
54
55 /* get the offset inside the fd to mmap */
56 ret = ustctl_get_mmap_read_offset(stream->chan->handle,
57 stream->buf, &mmap_offset);
58 if (ret != 0) {
59 ret = -errno;
60 perror("ustctl_get_mmap_read_offset");
61 goto end;
62 }
63 while (len > 0) {
64 ret = write(outfd, stream->mmap_base + mmap_offset, len);
65 if (ret >= len) {
66 len = 0;
67 } else if (ret < 0) {
68 ret = -errno;
69 perror("Error in file write");
70 goto end;
71 }
72 /* This won't block, but will start writeout asynchronously */
73 sync_file_range(outfd, stream->out_fd_offset, ret,
74 SYNC_FILE_RANGE_WRITE);
75 stream->out_fd_offset += ret;
76 }
77
78 lttng_consumer_sync_trace_file(stream, orig_offset);
79
80 goto end;
81
82 end:
83 return ret;
84 }
85
86 /*
87 * Splice the data from the ring buffer to the tracefile.
88 *
89 * Returns the number of bytes spliced.
90 */
91 int lttng_ustconsumer_on_read_subbuffer_splice(
92 struct lttng_consumer_local_data *ctx,
93 struct lttng_consumer_stream *stream, unsigned long len)
94 {
95 return -ENOSYS;
96 }
97
98 /*
99 * Take a snapshot for a specific fd
100 *
101 * Returns 0 on success, < 0 on error
102 */
103 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
104 struct lttng_consumer_stream *stream)
105 {
106 int ret = 0;
107
108 ret = ustctl_snapshot(stream->chan->handle, stream->buf);
109 if (ret != 0) {
110 ret = errno;
111 perror("Getting sub-buffer snapshot.");
112 }
113
114 return ret;
115 }
116
117 /*
118 * Get the produced position
119 *
120 * Returns 0 on success, < 0 on error
121 */
122 int lttng_ustconsumer_get_produced_snapshot(
123 struct lttng_consumer_local_data *ctx,
124 struct lttng_consumer_stream *stream,
125 unsigned long *pos)
126 {
127 int ret;
128
129 ret = ustctl_snapshot_get_produced(stream->chan->handle,
130 stream->buf, pos);
131 if (ret != 0) {
132 ret = errno;
133 perror("kernctl_snapshot_get_produced");
134 }
135
136 return ret;
137 }
138
139 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
140 int sock, struct pollfd *consumer_sockpoll)
141 {
142 ssize_t ret;
143 struct lttcomm_consumer_msg msg;
144
145 ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
146 if (ret != sizeof(msg)) {
147 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
148 return ret;
149 }
150 if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
151 return -ENOENT;
152 }
153
154 switch (msg.cmd_type) {
155 case LTTNG_CONSUMER_ADD_CHANNEL:
156 {
157 struct lttng_consumer_channel *new_channel;
158 int fds[1];
159 size_t nb_fd = 1;
160
161 /* block */
162 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
163 return -EINTR;
164 }
165 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
166 if (ret != sizeof(fds)) {
167 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
168 return ret;
169 }
170
171 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
172
173 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
174 fds[0], -1,
175 msg.u.channel.mmap_len,
176 msg.u.channel.max_sb_size);
177 if (new_channel == NULL) {
178 lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
179 goto end_nosignal;
180 }
181 if (ctx->on_recv_channel != NULL) {
182 ret = ctx->on_recv_channel(new_channel);
183 if (ret == 0) {
184 consumer_add_channel(new_channel);
185 } else if (ret < 0) {
186 goto end_nosignal;
187 }
188 } else {
189 consumer_add_channel(new_channel);
190 }
191 goto end_nosignal;
192 }
193 case LTTNG_CONSUMER_ADD_STREAM:
194 {
195 struct lttng_consumer_stream *new_stream;
196 int fds[2];
197 size_t nb_fd = 2;
198
199 /* block */
200 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
201 return -EINTR;
202 }
203 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
204 if (ret != sizeof(fds)) {
205 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
206 return ret;
207 }
208
209 DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
210 fds[0], fds[1]);
211 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
212 new_stream = consumer_allocate_stream(msg.u.channel.channel_key,
213 msg.u.stream.stream_key,
214 fds[0], fds[1],
215 msg.u.stream.state,
216 msg.u.stream.mmap_len,
217 msg.u.stream.output,
218 msg.u.stream.path_name,
219 msg.u.stream.uid,
220 msg.u.stream.gid);
221 if (new_stream == NULL) {
222 lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
223 goto end;
224 }
225 if (ctx->on_recv_stream != NULL) {
226 ret = ctx->on_recv_stream(new_stream);
227 if (ret == 0) {
228 consumer_add_stream(new_stream);
229 } else if (ret < 0) {
230 goto end;
231 }
232 } else {
233 consumer_add_stream(new_stream);
234 }
235 break;
236 }
237 case LTTNG_CONSUMER_UPDATE_STREAM:
238 {
239 return -ENOSYS;
240 #if 0
241 if (ctx->on_update_stream != NULL) {
242 ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
243 if (ret == 0) {
244 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
245 } else if (ret < 0) {
246 goto end;
247 }
248 } else {
249 consumer_change_stream_state(msg.u.stream.stream_key,
250 msg.u.stream.state);
251 }
252 #endif
253 break;
254 }
255 default:
256 break;
257 }
258 end:
259 /* signal the poll thread */
260 ret = write(ctx->consumer_poll_pipe[1], "4", 1);
261 if (ret < 0) {
262 perror("write consumer poll");
263 }
264 end_nosignal:
265 return 0;
266 }
267
268 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
269 {
270 struct lttng_ust_object_data obj;
271
272 obj.handle = -1;
273 obj.shm_fd = chan->shm_fd;
274 obj.wait_fd = chan->wait_fd;
275 obj.memory_map_size = chan->mmap_len;
276 chan->handle = ustctl_map_channel(&obj);
277 if (!chan->handle) {
278 return -ENOMEM;
279 }
280 /*
281 * The channel fds are passed to ustctl, we only keep a copy.
282 */
283 chan->shm_fd_is_copy = 1;
284 chan->wait_fd_is_copy = 1;
285
286 return 0;
287 }
288
289 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
290 {
291 ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
292 stream->hangup_flush_done = 1;
293 }
294
295 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
296 {
297 ustctl_unmap_channel(chan->handle);
298 }
299
300 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
301 {
302 struct lttng_ust_object_data obj;
303 int ret;
304
305 obj.handle = -1;
306 obj.shm_fd = stream->shm_fd;
307 obj.wait_fd = stream->wait_fd;
308 obj.memory_map_size = stream->mmap_len;
309 ret = ustctl_add_stream(stream->chan->handle, &obj);
310 if (ret)
311 return ret;
312 stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
313 if (!stream->buf)
314 return -EBUSY;
315 stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
316 if (!stream->mmap_base) {
317 return -EINVAL;
318 }
319 /*
320 * The stream fds are passed to ustctl, we only keep a copy.
321 */
322 stream->shm_fd_is_copy = 1;
323 stream->wait_fd_is_copy = 1;
324
325 return 0;
326 }
327
328 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
329 {
330 ustctl_close_stream_read(stream->chan->handle, stream->buf);
331 }
332
333
334 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
335 struct lttng_consumer_local_data *ctx)
336 {
337 unsigned long len;
338 int err;
339 long ret = 0;
340 struct lttng_ust_shm_handle *handle;
341 struct lttng_ust_lib_ring_buffer *buf;
342 char dummy;
343 ssize_t readlen;
344
345 DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
346 stream->wait_fd, stream->key);
347
348 /* We can consume the 1 byte written into the wait_fd by UST */
349 if (!stream->hangup_flush_done) {
350 do {
351 readlen = read(stream->wait_fd, &dummy, 1);
352 } while (readlen == -1 && errno == -EINTR);
353 if (readlen == -1) {
354 ret = readlen;
355 goto end;
356 }
357 }
358
359 buf = stream->buf;
360 handle = stream->chan->handle;
361 /* Get the next subbuffer */
362 err = ustctl_get_next_subbuf(handle, buf);
363 if (err != 0) {
364 ret = -ret; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
365 /*
366 * This is a debug message even for single-threaded consumer,
367 * because poll() have more relaxed criterions than get subbuf,
368 * so get_subbuf may fail for short race windows where poll()
369 * would issue wakeups.
370 */
371 DBG("Reserving sub buffer failed (everything is normal, "
372 "it is due to concurrency)");
373 goto end;
374 }
375 assert(stream->output == LTTNG_EVENT_MMAP);
376 /* read the used subbuffer size */
377 err = ustctl_get_padded_subbuf_size(handle, buf, &len);
378 assert(err == 0);
379 /* write the subbuffer to the tracefile */
380 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
381 if (ret < 0) {
382 /*
383 * display the error but continue processing to try
384 * to release the subbuffer
385 */
386 ERR("Error writing to tracefile");
387 }
388 err = ustctl_put_next_subbuf(handle, buf);
389 assert(err == 0);
390 end:
391 return ret;
392 }
393
394 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
395 {
396 int ret;
397
398 /* Opening the tracefile in write mode */
399 if (stream->path_name != NULL) {
400 ret = open(stream->path_name,
401 O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
402 if (ret < 0) {
403 ERR("Opening %s", stream->path_name);
404 perror("open");
405 goto error;
406 }
407 stream->out_fd = ret;
408 ret = chown(stream->path_name, stream->uid, stream->gid);
409 if (ret < 0) {
410 ERR("Changing ownership of %s", stream->path_name);
411 perror("chown");
412 }
413 }
414
415 /* we return 0 to let the library handle the FD internally */
416 return 0;
417
418 error:
419 return ret;
420 }
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