2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as published by the Free Software Foundation.
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.
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
26 #include <sys/socket.h>
27 #include <sys/types.h>
32 #include <common/common.h>
33 #include <common/kernel-ctl/kernel-ctl.h>
34 #include <common/sessiond-comm/sessiond-comm.h>
35 #include <common/sessiond-comm/relayd.h>
36 #include <common/compat/fcntl.h>
37 #include <common/pipe.h>
38 #include <common/relayd/relayd.h>
39 #include <common/utils.h>
40 #include <common/consumer-stream.h>
42 #include "kernel-consumer.h"
44 extern struct lttng_consumer_global_data consumer_data
;
45 extern int consumer_poll_timeout
;
46 extern volatile int consumer_quit
;
49 * Take a snapshot for a specific fd
51 * Returns 0 on success, < 0 on error
53 int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream
*stream
)
56 int infd
= stream
->wait_fd
;
58 ret
= kernctl_snapshot(infd
);
61 perror("Getting sub-buffer snapshot.");
68 * Get the produced position
70 * Returns 0 on success, < 0 on error
72 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream
*stream
,
76 int infd
= stream
->wait_fd
;
78 ret
= kernctl_snapshot_get_produced(infd
, pos
);
81 perror("kernctl_snapshot_get_produced");
88 * Get the consumerd position
90 * Returns 0 on success, < 0 on error
92 int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream
*stream
,
96 int infd
= stream
->wait_fd
;
98 ret
= kernctl_snapshot_get_consumed(infd
, pos
);
101 perror("kernctl_snapshot_get_consumed");
108 * Take a snapshot of all the stream of a channel
110 * Returns 0 on success, < 0 on error
112 int lttng_kconsumer_snapshot_channel(uint64_t key
, char *path
,
113 uint64_t relayd_id
, struct lttng_consumer_local_data
*ctx
)
116 unsigned long consumed_pos
, produced_pos
;
117 struct lttng_consumer_channel
*channel
;
118 struct lttng_consumer_stream
*stream
;
120 DBG("Kernel consumer snapshot channel %lu", key
);
124 channel
= consumer_find_channel(key
);
126 ERR("No channel found for key %lu", key
);
131 /* Splice is not supported yet for channel snapshot. */
132 if (channel
->output
!= CONSUMER_CHANNEL_MMAP
) {
133 ERR("Unsupported output %d", channel
->output
);
138 cds_list_for_each_entry(stream
, &channel
->streams
.head
, send_node
) {
140 * Lock stream because we are about to change its state.
142 pthread_mutex_lock(&stream
->lock
);
145 * Assign the received relayd ID so we can use it for streaming. The streams
146 * are not visible to anyone so this is OK to change it.
148 stream
->net_seq_idx
= relayd_id
;
149 channel
->relayd_id
= relayd_id
;
150 if (relayd_id
!= (uint64_t) -1ULL) {
151 ret
= consumer_send_relayd_stream(stream
, path
);
153 ERR("sending stream to relayd");
157 ret
= utils_create_stream_file(path
, stream
->name
,
158 stream
->chan
->tracefile_size
,
159 stream
->tracefile_count_current
,
160 stream
->uid
, stream
->gid
);
162 ERR("utils_create_stream_file");
166 stream
->out_fd
= ret
;
167 stream
->tracefile_size_current
= 0;
169 DBG("Kernel consumer snapshot stream %s/%s (%lu)", path
,
170 stream
->name
, stream
->key
);
173 ret
= kernctl_buffer_flush(stream
->wait_fd
);
175 ERR("Failed to flush kernel stream");
179 ret
= lttng_kconsumer_take_snapshot(stream
);
181 ERR("Taking kernel snapshot");
185 ret
= lttng_kconsumer_get_produced_snapshot(stream
, &produced_pos
);
187 ERR("Produced kernel snapshot position");
191 ret
= lttng_kconsumer_get_consumed_snapshot(stream
, &consumed_pos
);
193 ERR("Consumerd kernel snapshot position");
197 if (stream
->max_sb_size
== 0) {
198 ret
= kernctl_get_max_subbuf_size(stream
->wait_fd
,
199 &stream
->max_sb_size
);
201 ERR("Getting kernel max_sb_size");
206 while (consumed_pos
< produced_pos
) {
208 unsigned long len
, padded_len
;
210 DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos
);
212 ret
= kernctl_get_subbuf(stream
->wait_fd
, &consumed_pos
);
214 if (errno
!= EAGAIN
) {
215 PERROR("kernctl_get_subbuf snapshot");
218 DBG("Kernel consumer get subbuf failed. Skipping it.");
219 consumed_pos
+= stream
->max_sb_size
;
223 ret
= kernctl_get_subbuf_size(stream
->wait_fd
, &len
);
225 ERR("Snapshot kernctl_get_subbuf_size");
226 goto error_put_subbuf
;
229 ret
= kernctl_get_padded_subbuf_size(stream
->wait_fd
, &padded_len
);
231 ERR("Snapshot kernctl_get_padded_subbuf_size");
232 goto error_put_subbuf
;
235 read_len
= lttng_consumer_on_read_subbuffer_mmap(ctx
, stream
, len
,
238 * We write the padded len in local tracefiles but the data len
239 * when using a relay. Display the error but continue processing
240 * to try to release the subbuffer.
242 if (relayd_id
!= (uint64_t) -1ULL) {
243 if (read_len
!= len
) {
244 ERR("Error sending to the relay (ret: %zd != len: %lu)",
248 if (read_len
!= padded_len
) {
249 ERR("Error writing to tracefile (ret: %zd != len: %lu)",
250 read_len
, padded_len
);
254 ret
= kernctl_put_subbuf(stream
->wait_fd
);
256 ERR("Snapshot kernctl_put_subbuf");
259 consumed_pos
+= stream
->max_sb_size
;
262 if (relayd_id
== (uint64_t) -1ULL) {
263 ret
= close(stream
->out_fd
);
265 PERROR("Kernel consumer snapshot close out_fd");
270 close_relayd_stream(stream
);
271 stream
->net_seq_idx
= (uint64_t) -1ULL;
273 pthread_mutex_unlock(&stream
->lock
);
281 ret
= kernctl_put_subbuf(stream
->wait_fd
);
283 ERR("Snapshot kernctl_put_subbuf error path");
286 pthread_mutex_unlock(&stream
->lock
);
293 * Read the whole metadata available for a snapshot.
295 * Returns 0 on success, < 0 on error
297 int lttng_kconsumer_snapshot_metadata(uint64_t key
, char *path
,
298 uint64_t relayd_id
, struct lttng_consumer_local_data
*ctx
)
300 int ret
, use_relayd
= 0;
302 struct lttng_consumer_channel
*metadata_channel
;
303 struct lttng_consumer_stream
*metadata_stream
;
307 DBG("Kernel consumer snapshot metadata with key %" PRIu64
" at path %s",
312 metadata_channel
= consumer_find_channel(key
);
313 if (!metadata_channel
) {
314 ERR("Kernel snapshot metadata not found for key %" PRIu64
, key
);
319 metadata_stream
= metadata_channel
->metadata_stream
;
320 assert(metadata_stream
);
322 /* Flag once that we have a valid relayd for the stream. */
323 if (relayd_id
!= (uint64_t) -1ULL) {
328 ret
= consumer_send_relayd_stream(metadata_stream
, path
);
333 ret
= utils_create_stream_file(path
, metadata_stream
->name
,
334 metadata_stream
->chan
->tracefile_size
,
335 metadata_stream
->tracefile_count_current
,
336 metadata_stream
->uid
, metadata_stream
->gid
);
340 metadata_stream
->out_fd
= ret
;
344 ret_read
= lttng_kconsumer_read_subbuffer(metadata_stream
, ctx
);
346 if (ret_read
!= -EPERM
) {
347 ERR("Kernel snapshot reading metadata subbuffer (ret: %ld)",
351 /* ret_read is negative at this point so we will exit the loop. */
354 } while (ret_read
>= 0);
357 close_relayd_stream(metadata_stream
);
358 metadata_stream
->net_seq_idx
= (uint64_t) -1ULL;
360 ret
= close(metadata_stream
->out_fd
);
362 PERROR("Kernel consumer snapshot metadata close out_fd");
364 * Don't go on error here since the snapshot was successful at this
365 * point but somehow the close failed.
368 metadata_stream
->out_fd
= -1;
379 * Receive command from session daemon and process it.
381 * Return 1 on success else a negative value or 0.
383 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
384 int sock
, struct pollfd
*consumer_sockpoll
)
387 enum lttng_error_code ret_code
= LTTNG_OK
;
388 struct lttcomm_consumer_msg msg
;
390 ret
= lttcomm_recv_unix_sock(sock
, &msg
, sizeof(msg
));
391 if (ret
!= sizeof(msg
)) {
392 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_ERROR_RECV_CMD
);
398 if (msg
.cmd_type
== LTTNG_CONSUMER_STOP
) {
400 * Notify the session daemon that the command is completed.
402 * On transport layer error, the function call will print an error
403 * message so handling the returned code is a bit useless since we
404 * return an error code anyway.
406 (void) consumer_send_status_msg(sock
, ret_code
);
410 /* relayd needs RCU read-side protection */
413 switch (msg
.cmd_type
) {
414 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET
:
416 /* Session daemon status message are handled in the following call. */
417 ret
= consumer_add_relayd_socket(msg
.u
.relayd_sock
.net_index
,
418 msg
.u
.relayd_sock
.type
, ctx
, sock
, consumer_sockpoll
,
419 &msg
.u
.relayd_sock
.sock
, msg
.u
.relayd_sock
.session_id
);
422 case LTTNG_CONSUMER_ADD_CHANNEL
:
424 struct lttng_consumer_channel
*new_channel
;
427 /* First send a status message before receiving the fds. */
428 ret
= consumer_send_status_msg(sock
, ret_code
);
430 /* Somehow, the session daemon is not responding anymore. */
433 DBG("consumer_add_channel %" PRIu64
, msg
.u
.channel
.channel_key
);
434 new_channel
= consumer_allocate_channel(msg
.u
.channel
.channel_key
,
435 msg
.u
.channel
.session_id
, msg
.u
.channel
.pathname
,
436 msg
.u
.channel
.name
, msg
.u
.channel
.uid
, msg
.u
.channel
.gid
,
437 msg
.u
.channel
.relayd_id
, msg
.u
.channel
.output
,
438 msg
.u
.channel
.tracefile_size
,
439 msg
.u
.channel
.tracefile_count
, 0,
440 msg
.u
.channel
.monitor
);
441 if (new_channel
== NULL
) {
442 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_OUTFD_ERROR
);
445 new_channel
->nb_init_stream_left
= msg
.u
.channel
.nb_init_streams
;
446 switch (msg
.u
.channel
.output
) {
447 case LTTNG_EVENT_SPLICE
:
448 new_channel
->output
= CONSUMER_CHANNEL_SPLICE
;
450 case LTTNG_EVENT_MMAP
:
451 new_channel
->output
= CONSUMER_CHANNEL_MMAP
;
454 ERR("Channel output unknown %d", msg
.u
.channel
.output
);
458 /* Translate and save channel type. */
459 switch (msg
.u
.channel
.type
) {
460 case CONSUMER_CHANNEL_TYPE_DATA
:
461 case CONSUMER_CHANNEL_TYPE_METADATA
:
462 new_channel
->type
= msg
.u
.channel
.type
;
469 if (ctx
->on_recv_channel
!= NULL
) {
470 ret_recv
= ctx
->on_recv_channel(new_channel
);
472 ret
= consumer_add_channel(new_channel
, ctx
);
473 } else if (ret_recv
< 0) {
477 ret
= consumer_add_channel(new_channel
, ctx
);
480 /* If we received an error in add_channel, we need to report it. */
482 ret
= consumer_send_status_msg(sock
, ret
);
491 case LTTNG_CONSUMER_ADD_STREAM
:
494 struct lttng_pipe
*stream_pipe
;
495 struct lttng_consumer_stream
*new_stream
;
496 struct lttng_consumer_channel
*channel
;
500 * Get stream's channel reference. Needed when adding the stream to the
503 channel
= consumer_find_channel(msg
.u
.stream
.channel_key
);
506 * We could not find the channel. Can happen if cpu hotplug
507 * happens while tearing down.
509 ERR("Unable to find channel key %" PRIu64
, msg
.u
.stream
.channel_key
);
510 ret_code
= LTTNG_ERR_KERN_CHAN_NOT_FOUND
;
513 /* First send a status message before receiving the fds. */
514 ret
= consumer_send_status_msg(sock
, ret_code
);
516 /* Somehow, the session daemon is not responding anymore. */
519 if (ret_code
!= LTTNG_OK
) {
520 /* Channel was not found. */
525 if (lttng_consumer_poll_socket(consumer_sockpoll
) < 0) {
530 /* Get stream file descriptor from socket */
531 ret
= lttcomm_recv_fds_unix_sock(sock
, &fd
, 1);
532 if (ret
!= sizeof(fd
)) {
533 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_ERROR_RECV_FD
);
539 * Send status code to session daemon only if the recv works. If the
540 * above recv() failed, the session daemon is notified through the
541 * error socket and the teardown is eventually done.
543 ret
= consumer_send_status_msg(sock
, ret_code
);
545 /* Somehow, the session daemon is not responding anymore. */
549 new_stream
= consumer_allocate_stream(channel
->key
,
551 LTTNG_CONSUMER_ACTIVE_STREAM
,
560 if (new_stream
== NULL
) {
565 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_OUTFD_ERROR
);
571 new_stream
->chan
= channel
;
572 new_stream
->wait_fd
= fd
;
573 switch (channel
->output
) {
574 case CONSUMER_CHANNEL_SPLICE
:
575 new_stream
->output
= LTTNG_EVENT_SPLICE
;
577 case CONSUMER_CHANNEL_MMAP
:
578 new_stream
->output
= LTTNG_EVENT_MMAP
;
581 ERR("Stream output unknown %d", channel
->output
);
586 * We've just assigned the channel to the stream so increment the
587 * refcount right now. We don't need to increment the refcount for
588 * streams in no monitor because we handle manually the cleanup of
589 * those. It is very important to make sure there is NO prior
590 * consumer_del_stream() calls or else the refcount will be unbalanced.
592 if (channel
->monitor
) {
593 uatomic_inc(&new_stream
->chan
->refcount
);
597 * The buffer flush is done on the session daemon side for the kernel
598 * so no need for the stream "hangup_flush_done" variable to be
599 * tracked. This is important for a kernel stream since we don't rely
600 * on the flush state of the stream to read data. It's not the case for
601 * user space tracing.
603 new_stream
->hangup_flush_done
= 0;
605 if (ctx
->on_recv_stream
) {
606 ret
= ctx
->on_recv_stream(new_stream
);
608 consumer_stream_free(new_stream
);
613 if (new_stream
->metadata_flag
) {
614 channel
->metadata_stream
= new_stream
;
617 /* Do not monitor this stream. */
618 if (!channel
->monitor
) {
619 DBG("Kernel consumer add stream %s in no monitor mode with "
620 "relayd id %" PRIu64
, new_stream
->name
,
621 new_stream
->net_seq_idx
);
622 cds_list_add(&new_stream
->send_node
, &channel
->streams
.head
);
626 ret
= consumer_send_relayd_stream(new_stream
, NULL
);
628 consumer_stream_free(new_stream
);
632 /* Get the right pipe where the stream will be sent. */
633 if (new_stream
->metadata_flag
) {
634 stream_pipe
= ctx
->consumer_metadata_pipe
;
636 stream_pipe
= ctx
->consumer_data_pipe
;
639 ret
= lttng_pipe_write(stream_pipe
, &new_stream
, sizeof(new_stream
));
641 ERR("Consumer write %s stream to pipe %d",
642 new_stream
->metadata_flag
? "metadata" : "data",
643 lttng_pipe_get_writefd(stream_pipe
));
644 consumer_stream_free(new_stream
);
648 DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64
,
649 new_stream
->name
, fd
, new_stream
->relayd_stream_id
);
652 case LTTNG_CONSUMER_UPDATE_STREAM
:
657 case LTTNG_CONSUMER_DESTROY_RELAYD
:
659 uint64_t index
= msg
.u
.destroy_relayd
.net_seq_idx
;
660 struct consumer_relayd_sock_pair
*relayd
;
662 DBG("Kernel consumer destroying relayd %" PRIu64
, index
);
664 /* Get relayd reference if exists. */
665 relayd
= consumer_find_relayd(index
);
666 if (relayd
== NULL
) {
667 DBG("Unable to find relayd %" PRIu64
, index
);
668 ret_code
= LTTNG_ERR_NO_CONSUMER
;
672 * Each relayd socket pair has a refcount of stream attached to it
673 * which tells if the relayd is still active or not depending on the
676 * This will set the destroy flag of the relayd object and destroy it
677 * if the refcount reaches zero when called.
679 * The destroy can happen either here or when a stream fd hangs up.
682 consumer_flag_relayd_for_destroy(relayd
);
685 ret
= consumer_send_status_msg(sock
, ret_code
);
687 /* Somehow, the session daemon is not responding anymore. */
693 case LTTNG_CONSUMER_DATA_PENDING
:
696 uint64_t id
= msg
.u
.data_pending
.session_id
;
698 DBG("Kernel consumer data pending command for id %" PRIu64
, id
);
700 ret
= consumer_data_pending(id
);
702 /* Send back returned value to session daemon */
703 ret
= lttcomm_send_unix_sock(sock
, &ret
, sizeof(ret
));
705 PERROR("send data pending ret code");
710 * No need to send back a status message since the data pending
711 * returned value is the response.
715 case LTTNG_CONSUMER_SNAPSHOT_CHANNEL
:
717 if (msg
.u
.snapshot_channel
.metadata
== 1) {
718 ret
= lttng_kconsumer_snapshot_metadata(msg
.u
.snapshot_channel
.key
,
719 msg
.u
.snapshot_channel
.pathname
,
720 msg
.u
.snapshot_channel
.relayd_id
, ctx
);
722 ERR("Snapshot metadata failed");
723 ret_code
= LTTNG_ERR_KERN_META_FAIL
;
726 ret
= lttng_kconsumer_snapshot_channel(msg
.u
.snapshot_channel
.key
,
727 msg
.u
.snapshot_channel
.pathname
,
728 msg
.u
.snapshot_channel
.relayd_id
, ctx
);
730 ERR("Snapshot channel failed");
731 ret_code
= LTTNG_ERR_KERN_CHAN_FAIL
;
735 ret
= consumer_send_status_msg(sock
, ret_code
);
737 /* Somehow, the session daemon is not responding anymore. */
742 case LTTNG_CONSUMER_DESTROY_CHANNEL
:
744 uint64_t key
= msg
.u
.destroy_channel
.key
;
745 struct lttng_consumer_channel
*channel
;
747 channel
= consumer_find_channel(key
);
749 ERR("Kernel consumer destroy channel %" PRIu64
" not found", key
);
750 ret_code
= LTTNG_ERR_KERN_CHAN_NOT_FOUND
;
753 ret
= consumer_send_status_msg(sock
, ret_code
);
755 /* Somehow, the session daemon is not responding anymore. */
760 * This command should ONLY be issued for channel with streams set in
763 assert(!channel
->monitor
);
766 * The refcount should ALWAYS be 0 in the case of a channel in no
769 assert(!uatomic_sub_return(&channel
->refcount
, 1));
771 consumer_del_channel(channel
);
783 * Return 1 to indicate success since the 0 value can be a socket
784 * shutdown during the recv() or send() call.
790 /* This will issue a consumer stop. */
795 * Consume data on a file descriptor and write it on a trace file.
797 ssize_t
lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream
*stream
,
798 struct lttng_consumer_local_data
*ctx
)
800 unsigned long len
, subbuf_size
, padding
;
803 int infd
= stream
->wait_fd
;
805 DBG("In read_subbuffer (infd : %d)", infd
);
806 /* Get the next subbuffer */
807 err
= kernctl_get_next_subbuf(infd
);
811 * This is a debug message even for single-threaded consumer,
812 * because poll() have more relaxed criterions than get subbuf,
813 * so get_subbuf may fail for short race windows where poll()
814 * would issue wakeups.
816 DBG("Reserving sub buffer failed (everything is normal, "
817 "it is due to concurrency)");
821 /* Get the full subbuffer size including padding */
822 err
= kernctl_get_padded_subbuf_size(infd
, &len
);
825 perror("Getting sub-buffer len failed.");
830 switch (stream
->chan
->output
) {
831 case CONSUMER_CHANNEL_SPLICE
:
833 * XXX: The lttng-modules splice "actor" does not handle copying
834 * partial pages hence only using the subbuffer size without the
835 * padding makes the splice fail.
840 /* splice the subbuffer to the tracefile */
841 ret
= lttng_consumer_on_read_subbuffer_splice(ctx
, stream
, subbuf_size
,
844 * XXX: Splice does not support network streaming so the return value
845 * is simply checked against subbuf_size and not like the mmap() op.
847 if (ret
!= subbuf_size
) {
849 * display the error but continue processing to try
850 * to release the subbuffer
852 ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
856 case CONSUMER_CHANNEL_MMAP
:
857 /* Get subbuffer size without padding */
858 err
= kernctl_get_subbuf_size(infd
, &subbuf_size
);
861 perror("Getting sub-buffer len failed.");
866 /* Make sure the tracer is not gone mad on us! */
867 assert(len
>= subbuf_size
);
869 padding
= len
- subbuf_size
;
871 /* write the subbuffer to the tracefile */
872 ret
= lttng_consumer_on_read_subbuffer_mmap(ctx
, stream
, subbuf_size
,
875 * The mmap operation should write subbuf_size amount of data when
876 * network streaming or the full padding (len) size when we are _not_
879 if ((ret
!= subbuf_size
&& stream
->net_seq_idx
!= (uint64_t) -1ULL) ||
880 (ret
!= len
&& stream
->net_seq_idx
== (uint64_t) -1ULL)) {
882 * Display the error but continue processing to try to release the
885 ERR("Error writing to tracefile "
886 "(ret: %zd != len: %lu != subbuf_size: %lu)",
887 ret
, len
, subbuf_size
);
891 ERR("Unknown output method");
895 err
= kernctl_put_next_subbuf(infd
);
898 if (errno
== EFAULT
) {
899 perror("Error in unreserving sub buffer\n");
900 } else if (errno
== EIO
) {
901 /* Should never happen with newer LTTng versions */
902 perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
913 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream
*stream
)
920 * Don't create anything if this is set for streaming or should not be
923 if (stream
->net_seq_idx
== (uint64_t) -1ULL && stream
->chan
->monitor
) {
924 ret
= utils_create_stream_file(stream
->chan
->pathname
, stream
->name
,
925 stream
->chan
->tracefile_size
, stream
->tracefile_count_current
,
926 stream
->uid
, stream
->gid
);
930 stream
->out_fd
= ret
;
931 stream
->tracefile_size_current
= 0;
934 if (stream
->output
== LTTNG_EVENT_MMAP
) {
935 /* get the len of the mmap region */
936 unsigned long mmap_len
;
938 ret
= kernctl_get_mmap_len(stream
->wait_fd
, &mmap_len
);
941 PERROR("kernctl_get_mmap_len");
944 stream
->mmap_len
= (size_t) mmap_len
;
946 stream
->mmap_base
= mmap(NULL
, stream
->mmap_len
, PROT_READ
,
947 MAP_PRIVATE
, stream
->wait_fd
, 0);
948 if (stream
->mmap_base
== MAP_FAILED
) {
949 PERROR("Error mmaping");
955 /* we return 0 to let the library handle the FD internally */
959 if (stream
->out_fd
>= 0) {
962 err
= close(stream
->out_fd
);
971 * Check if data is still being extracted from the buffers for a specific
972 * stream. Consumer data lock MUST be acquired before calling this function
973 * and the stream lock.
975 * Return 1 if the traced data are still getting read else 0 meaning that the
976 * data is available for trace viewer reading.
978 int lttng_kconsumer_data_pending(struct lttng_consumer_stream
*stream
)
984 ret
= kernctl_get_next_subbuf(stream
->wait_fd
);
986 /* There is still data so let's put back this subbuffer. */
987 ret
= kernctl_put_subbuf(stream
->wait_fd
);
989 ret
= 1; /* Data is pending */
993 /* Data is NOT pending and ready to be read. */