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 * Find a relayd and send the stream
110 * Returns 0 on success, < 0 on error
113 int send_relayd_stream(struct lttng_consumer_stream
*stream
, char *path
)
115 struct consumer_relayd_sock_pair
*relayd
;
122 stream_path
= stream
->chan
->pathname
;
124 /* The stream is not metadata. Get relayd reference if exists. */
126 relayd
= consumer_find_relayd(stream
->net_seq_idx
);
127 if (relayd
!= NULL
) {
128 /* Add stream on the relayd */
129 pthread_mutex_lock(&relayd
->ctrl_sock_mutex
);
130 ret
= relayd_add_stream(&relayd
->control_sock
,
131 stream
->name
, stream_path
,
132 &stream
->relayd_stream_id
,
133 stream
->chan
->tracefile_size
,
134 stream
->chan
->tracefile_count
);
135 pthread_mutex_unlock(&relayd
->ctrl_sock_mutex
);
139 uatomic_inc(&relayd
->refcount
);
140 } else if (stream
->net_seq_idx
!= (uint64_t) -1ULL) {
141 ERR("Network sequence index %" PRIu64
" unknown. Not adding stream.",
142 stream
->net_seq_idx
);
153 * Find a relayd and close the stream
156 void close_relayd_stream(struct lttng_consumer_stream
*stream
)
158 struct consumer_relayd_sock_pair
*relayd
;
160 /* The stream is not metadata. Get relayd reference if exists. */
162 relayd
= consumer_find_relayd(stream
->net_seq_idx
);
163 if (relayd
!= NULL
) {
164 consumer_stream_relayd_close(stream
, relayd
);
170 * Take a snapshot of all the stream of a channel
172 * Returns 0 on success, < 0 on error
174 int lttng_kconsumer_snapshot_channel(uint64_t key
, char *path
,
175 uint64_t relayd_id
, struct lttng_consumer_local_data
*ctx
)
178 unsigned long consumed_pos
, produced_pos
;
179 struct lttng_consumer_channel
*channel
;
180 struct lttng_consumer_stream
*stream
;
182 DBG("Kernel consumer snapshot channel %lu", key
);
186 channel
= consumer_find_channel(key
);
188 ERR("No channel found for key %lu", key
);
193 /* Splice is not supported yet for channel snapshot. */
194 if (channel
->output
!= CONSUMER_CHANNEL_MMAP
) {
195 ERR("Unsupported output %d", channel
->output
);
200 cds_list_for_each_entry(stream
, &channel
->stream_no_monitor_list
.head
,
203 * Lock stream because we are about to change its state.
205 pthread_mutex_lock(&stream
->lock
);
207 stream
->net_seq_idx
= relayd_id
;
208 channel
->relayd_id
= relayd_id
;
209 if (relayd_id
!= (uint64_t) -1ULL) {
210 ret
= send_relayd_stream(stream
, path
);
212 ERR("sending stream to relayd");
215 DBG("Stream %s sent to the relayd", stream
->name
);
217 ret
= utils_create_stream_file(path
, stream
->name
,
218 stream
->chan
->tracefile_size
, stream
->tracefile_count_current
,
219 stream
->uid
, stream
->gid
);
221 ERR("utils_create_stream_file");
225 stream
->out_fd
= ret
;
226 stream
->tracefile_size_current
= 0;
228 DBG("Kernel consumer snapshot stream %s/%s (%lu)", path
,
229 stream
->name
, stream
->key
);
232 ret
= kernctl_buffer_flush(stream
->wait_fd
);
234 ERR("Failed to flush kernel metadata stream");
238 ret
= lttng_kconsumer_take_snapshot(stream
);
240 ERR("Taking kernel snapshot");
244 ret
= lttng_kconsumer_get_produced_snapshot(stream
, &produced_pos
);
246 ERR("Produced kernel snapshot position");
250 ret
= lttng_kconsumer_get_consumed_snapshot(stream
, &consumed_pos
);
252 ERR("Consumerd kernel snapshot position");
256 if (stream
->max_sb_size
== 0) {
257 ret
= kernctl_get_max_subbuf_size(stream
->wait_fd
,
258 &stream
->max_sb_size
);
260 ERR("Getting kernel max_sb_size");
265 while (consumed_pos
< produced_pos
) {
267 unsigned long len
, padded_len
;
269 DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos
);
271 ret
= kernctl_get_subbuf(stream
->wait_fd
, &consumed_pos
);
273 if (errno
!= EAGAIN
) {
274 PERROR("kernctl_get_subbuf snapshot");
277 DBG("Kernel consumer get subbuf failed. Skipping it.");
278 consumed_pos
+= stream
->max_sb_size
;
282 ret
= kernctl_get_subbuf_size(stream
->wait_fd
, &len
);
284 ERR("Snapshot kernctl_get_subbuf_size");
288 ret
= kernctl_get_padded_subbuf_size(stream
->wait_fd
, &padded_len
);
290 ERR("Snapshot kernctl_get_padded_subbuf_size");
294 read_len
= lttng_consumer_on_read_subbuffer_mmap(ctx
, stream
, len
,
297 * We write the padded len in local tracefiles but the
298 * data len when using a relay.
299 * Display the error but continue processing to try to
300 * release the subbuffer.
302 if (relayd_id
!= (uint64_t) -1ULL) {
303 if (read_len
!= len
) {
304 ERR("Error sending to the relay (ret: %zd != len: %lu)",
308 if (read_len
!= padded_len
) {
309 ERR("Error writing to tracefile (ret: %zd != len: %lu)",
310 read_len
, padded_len
);
314 ret
= kernctl_put_subbuf(stream
->wait_fd
);
316 ERR("Snapshot kernctl_put_subbuf");
319 consumed_pos
+= stream
->max_sb_size
;
322 if (relayd_id
== (uint64_t) -1ULL) {
323 ret
= close(stream
->out_fd
);
325 PERROR("Kernel consumer snapshot close out_fd");
330 close_relayd_stream(stream
);
331 stream
->net_seq_idx
= (uint64_t) -1ULL;
333 pthread_mutex_unlock(&stream
->lock
);
341 pthread_mutex_unlock(&stream
->lock
);
348 * Read the whole metadata available for a snapshot.
350 * Returns 0 on success, < 0 on error
352 int lttng_kconsumer_snapshot_metadata(uint64_t key
, char *path
,
353 struct lttng_consumer_local_data
*ctx
)
355 struct lttng_consumer_channel
*metadata_channel
;
356 struct lttng_consumer_stream
*metadata_stream
;
359 DBG("Kernel consumer snapshot metadata with key %" PRIu64
" at path %s",
364 metadata_channel
= consumer_find_channel(key
);
365 if (!metadata_channel
) {
366 ERR("Snapshot kernel metadata channel not found for key %lu", key
);
371 metadata_stream
= metadata_channel
->metadata_stream
;
372 assert(metadata_stream
);
374 ret
= utils_create_stream_file(path
, metadata_stream
->name
,
375 metadata_stream
->chan
->tracefile_size
,
376 metadata_stream
->tracefile_count_current
,
377 metadata_stream
->uid
, metadata_stream
->gid
);
381 metadata_stream
->out_fd
= ret
;
385 ret
= lttng_kconsumer_read_subbuffer(metadata_stream
, ctx
);
388 ERR("Kernel snapshot reading subbuffer");
391 /* "ret" is negative at this point so we will exit the loop. */
403 * Receive command from session daemon and process it.
405 * Return 1 on success else a negative value or 0.
407 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
408 int sock
, struct pollfd
*consumer_sockpoll
)
411 enum lttng_error_code ret_code
= LTTNG_OK
;
412 struct lttcomm_consumer_msg msg
;
414 ret
= lttcomm_recv_unix_sock(sock
, &msg
, sizeof(msg
));
415 if (ret
!= sizeof(msg
)) {
416 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_ERROR_RECV_CMD
);
422 if (msg
.cmd_type
== LTTNG_CONSUMER_STOP
) {
424 * Notify the session daemon that the command is completed.
426 * On transport layer error, the function call will print an error
427 * message so handling the returned code is a bit useless since we
428 * return an error code anyway.
430 (void) consumer_send_status_msg(sock
, ret_code
);
434 /* relayd needs RCU read-side protection */
437 switch (msg
.cmd_type
) {
438 case LTTNG_CONSUMER_ADD_RELAYD_SOCKET
:
440 /* Session daemon status message are handled in the following call. */
441 ret
= consumer_add_relayd_socket(msg
.u
.relayd_sock
.net_index
,
442 msg
.u
.relayd_sock
.type
, ctx
, sock
, consumer_sockpoll
,
443 &msg
.u
.relayd_sock
.sock
, msg
.u
.relayd_sock
.session_id
);
446 case LTTNG_CONSUMER_ADD_CHANNEL
:
448 struct lttng_consumer_channel
*new_channel
;
451 /* First send a status message before receiving the fds. */
452 ret
= consumer_send_status_msg(sock
, ret_code
);
454 /* Somehow, the session daemon is not responding anymore. */
457 DBG("consumer_add_channel %" PRIu64
, msg
.u
.channel
.channel_key
);
458 new_channel
= consumer_allocate_channel(msg
.u
.channel
.channel_key
,
459 msg
.u
.channel
.session_id
, msg
.u
.channel
.pathname
,
460 msg
.u
.channel
.name
, msg
.u
.channel
.uid
, msg
.u
.channel
.gid
,
461 msg
.u
.channel
.relayd_id
, msg
.u
.channel
.output
,
462 msg
.u
.channel
.tracefile_size
,
463 msg
.u
.channel
.tracefile_count
,
464 msg
.u
.channel
.monitor
);
465 if (new_channel
== NULL
) {
466 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_OUTFD_ERROR
);
469 new_channel
->nb_init_stream_left
= msg
.u
.channel
.nb_init_streams
;
471 /* Translate and save channel type. */
472 switch (msg
.u
.channel
.type
) {
473 case CONSUMER_CHANNEL_TYPE_DATA
:
474 case CONSUMER_CHANNEL_TYPE_METADATA
:
475 new_channel
->type
= msg
.u
.channel
.type
;
482 if (ctx
->on_recv_channel
!= NULL
) {
483 ret_recv
= ctx
->on_recv_channel(new_channel
);
485 ret
= consumer_add_channel(new_channel
, ctx
);
486 } else if (ret_recv
< 0) {
490 ret
= consumer_add_channel(new_channel
, ctx
);
493 /* If we received an error in add_channel, we need to report it. */
495 ret
= consumer_send_status_msg(sock
, ret
);
504 case LTTNG_CONSUMER_ADD_STREAM
:
507 struct lttng_pipe
*stream_pipe
;
508 struct lttng_consumer_stream
*new_stream
;
509 struct lttng_consumer_channel
*channel
;
513 * Get stream's channel reference. Needed when adding the stream to the
516 channel
= consumer_find_channel(msg
.u
.stream
.channel_key
);
519 * We could not find the channel. Can happen if cpu hotplug
520 * happens while tearing down.
522 ERR("Unable to find channel key %" PRIu64
, msg
.u
.stream
.channel_key
);
523 ret_code
= LTTNG_ERR_KERN_CHAN_NOT_FOUND
;
526 /* First send a status message before receiving the fds. */
527 ret
= consumer_send_status_msg(sock
, ret_code
);
530 * Somehow, the session daemon is not responding
535 if (ret_code
!= LTTNG_OK
) {
537 * Channel was not found.
543 if (lttng_consumer_poll_socket(consumer_sockpoll
) < 0) {
548 /* Get stream file descriptor from socket */
549 ret
= lttcomm_recv_fds_unix_sock(sock
, &fd
, 1);
550 if (ret
!= sizeof(fd
)) {
551 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_ERROR_RECV_FD
);
557 * Send status code to session daemon only if the recv works. If the
558 * above recv() failed, the session daemon is notified through the
559 * error socket and the teardown is eventually done.
561 ret
= consumer_send_status_msg(sock
, ret_code
);
563 /* Somehow, the session daemon is not responding anymore. */
567 new_stream
= consumer_allocate_stream(channel
->key
,
569 LTTNG_CONSUMER_ACTIVE_STREAM
,
578 if (new_stream
== NULL
) {
583 lttng_consumer_send_error(ctx
, LTTCOMM_CONSUMERD_OUTFD_ERROR
);
588 new_stream
->chan
= channel
;
589 new_stream
->wait_fd
= fd
;
590 switch (channel
->output
) {
591 case CONSUMER_CHANNEL_SPLICE
:
592 new_stream
->output
= LTTNG_EVENT_SPLICE
;
594 case CONSUMER_CHANNEL_MMAP
:
595 new_stream
->output
= LTTNG_EVENT_MMAP
;
598 ERR("Stream output unknown %d", channel
->output
);
603 * We've just assigned the channel to the stream so increment the
604 * refcount right now. We don't need to increment the refcount for
605 * streams in no monitor because we handle manually the cleanup of
606 * those. It is very important to make sure there is NO prior
607 * consumer_del_stream() calls or else the refcount will be unbalanced.
609 if (channel
->monitor
) {
610 uatomic_inc(&new_stream
->chan
->refcount
);
614 * The buffer flush is done on the session daemon side for the kernel
615 * so no need for the stream "hangup_flush_done" variable to be
616 * tracked. This is important for a kernel stream since we don't rely
617 * on the flush state of the stream to read data. It's not the case for
618 * user space tracing.
620 new_stream
->hangup_flush_done
= 0;
622 ret
= send_relayd_stream(new_stream
, NULL
);
624 consumer_del_stream(new_stream
, NULL
);
628 if (ctx
->on_recv_stream
) {
629 ret
= ctx
->on_recv_stream(new_stream
);
631 consumer_del_stream(new_stream
, NULL
);
636 if (new_stream
->metadata_flag
) {
637 channel
->metadata_stream
= new_stream
;
640 /* Do not monitor this stream. */
641 if (!channel
->monitor
) {
642 DBG("Kernel consumer add stream %s in no monitor mode with"
643 "relayd id %" PRIu64
, new_stream
->name
,
644 new_stream
->relayd_stream_id
);
645 cds_list_add(&new_stream
->no_monitor_node
,
646 &channel
->stream_no_monitor_list
.head
);
650 /* Get the right pipe where the stream will be sent. */
651 if (new_stream
->metadata_flag
) {
652 stream_pipe
= ctx
->consumer_metadata_pipe
;
654 stream_pipe
= ctx
->consumer_data_pipe
;
657 ret
= lttng_pipe_write(stream_pipe
, &new_stream
, sizeof(new_stream
));
659 ERR("Consumer write %s stream to pipe %d",
660 new_stream
->metadata_flag
? "metadata" : "data",
661 lttng_pipe_get_writefd(stream_pipe
));
662 consumer_del_stream(new_stream
, NULL
);
666 DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64
,
667 new_stream
->name
, fd
, new_stream
->relayd_stream_id
);
670 case LTTNG_CONSUMER_UPDATE_STREAM
:
675 case LTTNG_CONSUMER_DESTROY_RELAYD
:
677 uint64_t index
= msg
.u
.destroy_relayd
.net_seq_idx
;
678 struct consumer_relayd_sock_pair
*relayd
;
680 DBG("Kernel consumer destroying relayd %" PRIu64
, index
);
682 /* Get relayd reference if exists. */
683 relayd
= consumer_find_relayd(index
);
684 if (relayd
== NULL
) {
685 DBG("Unable to find relayd %" PRIu64
, index
);
686 ret_code
= LTTNG_ERR_NO_CONSUMER
;
690 * Each relayd socket pair has a refcount of stream attached to it
691 * which tells if the relayd is still active or not depending on the
694 * This will set the destroy flag of the relayd object and destroy it
695 * if the refcount reaches zero when called.
697 * The destroy can happen either here or when a stream fd hangs up.
700 consumer_flag_relayd_for_destroy(relayd
);
703 ret
= consumer_send_status_msg(sock
, ret_code
);
705 /* Somehow, the session daemon is not responding anymore. */
711 case LTTNG_CONSUMER_DATA_PENDING
:
714 uint64_t id
= msg
.u
.data_pending
.session_id
;
716 DBG("Kernel consumer data pending command for id %" PRIu64
, id
);
718 ret
= consumer_data_pending(id
);
720 /* Send back returned value to session daemon */
721 ret
= lttcomm_send_unix_sock(sock
, &ret
, sizeof(ret
));
723 PERROR("send data pending ret code");
728 * No need to send back a status message since the data pending
729 * returned value is the response.
733 case LTTNG_CONSUMER_SNAPSHOT_CHANNEL
:
735 if (msg
.u
.snapshot_channel
.metadata
== 1) {
736 ret
= lttng_kconsumer_snapshot_metadata(msg
.u
.snapshot_channel
.key
,
737 msg
.u
.snapshot_channel
.pathname
, ctx
);
739 ERR("Snapshot metadata failed");
740 ret_code
= LTTNG_ERR_KERN_META_FAIL
;
743 ret
= lttng_kconsumer_snapshot_channel(msg
.u
.snapshot_channel
.key
,
744 msg
.u
.snapshot_channel
.pathname
,
745 msg
.u
.snapshot_channel
.relayd_id
, ctx
);
747 ERR("Snapshot channel failed");
748 ret_code
= LTTNG_ERR_KERN_CHAN_FAIL
;
752 ret
= consumer_send_status_msg(sock
, ret_code
);
754 /* Somehow, the session daemon is not responding anymore. */
759 case LTTNG_CONSUMER_DESTROY_CHANNEL
:
761 uint64_t key
= msg
.u
.destroy_channel
.key
;
762 struct lttng_consumer_channel
*channel
;
764 channel
= consumer_find_channel(key
);
766 ERR("Kernel consumer destroy channel %" PRIu64
" not found", key
);
767 ret_code
= LTTNG_ERR_KERN_CHAN_NOT_FOUND
;
770 ret
= consumer_send_status_msg(sock
, ret_code
);
772 /* Somehow, the session daemon is not responding anymore. */
777 * This command should ONLY be issued for channel with streams set in
780 assert(!channel
->monitor
);
783 * The refcount should ALWAYS be 0 in the case of a channel in no
786 assert(!uatomic_sub_return(&channel
->refcount
, 1));
788 consumer_del_channel(channel
);
800 * Return 1 to indicate success since the 0 value can be a socket
801 * shutdown during the recv() or send() call.
807 /* This will issue a consumer stop. */
812 * Consume data on a file descriptor and write it on a trace file.
814 ssize_t
lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream
*stream
,
815 struct lttng_consumer_local_data
*ctx
)
817 unsigned long len
, subbuf_size
, padding
;
820 int infd
= stream
->wait_fd
;
822 DBG("In read_subbuffer (infd : %d)", infd
);
823 /* Get the next subbuffer */
824 err
= kernctl_get_next_subbuf(infd
);
828 * This is a debug message even for single-threaded consumer,
829 * because poll() have more relaxed criterions than get subbuf,
830 * so get_subbuf may fail for short race windows where poll()
831 * would issue wakeups.
833 DBG("Reserving sub buffer failed (everything is normal, "
834 "it is due to concurrency)");
838 /* Get the full subbuffer size including padding */
839 err
= kernctl_get_padded_subbuf_size(infd
, &len
);
842 perror("Getting sub-buffer len failed.");
847 switch (stream
->chan
->output
) {
848 case CONSUMER_CHANNEL_SPLICE
:
850 * XXX: The lttng-modules splice "actor" does not handle copying
851 * partial pages hence only using the subbuffer size without the
852 * padding makes the splice fail.
857 /* splice the subbuffer to the tracefile */
858 ret
= lttng_consumer_on_read_subbuffer_splice(ctx
, stream
, subbuf_size
,
861 * XXX: Splice does not support network streaming so the return value
862 * is simply checked against subbuf_size and not like the mmap() op.
864 if (ret
!= subbuf_size
) {
866 * display the error but continue processing to try
867 * to release the subbuffer
869 ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
873 case CONSUMER_CHANNEL_MMAP
:
874 /* Get subbuffer size without padding */
875 err
= kernctl_get_subbuf_size(infd
, &subbuf_size
);
878 perror("Getting sub-buffer len failed.");
883 /* Make sure the tracer is not gone mad on us! */
884 assert(len
>= subbuf_size
);
886 padding
= len
- subbuf_size
;
888 /* write the subbuffer to the tracefile */
889 ret
= lttng_consumer_on_read_subbuffer_mmap(ctx
, stream
, subbuf_size
,
892 * The mmap operation should write subbuf_size amount of data when
893 * network streaming or the full padding (len) size when we are _not_
896 if ((ret
!= subbuf_size
&& stream
->net_seq_idx
!= (uint64_t) -1ULL) ||
897 (ret
!= len
&& stream
->net_seq_idx
== (uint64_t) -1ULL)) {
899 * Display the error but continue processing to try to release the
902 ERR("Error writing to tracefile "
903 "(ret: %zd != len: %lu != subbuf_size: %lu)",
904 ret
, len
, subbuf_size
);
908 ERR("Unknown output method");
912 err
= kernctl_put_next_subbuf(infd
);
915 if (errno
== EFAULT
) {
916 perror("Error in unreserving sub buffer\n");
917 } else if (errno
== EIO
) {
918 /* Should never happen with newer LTTng versions */
919 perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
930 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream
*stream
)
937 * Don't create anything if this is set for streaming or should not be
940 if (stream
->net_seq_idx
== (uint64_t) -1ULL && stream
->chan
->monitor
) {
941 ret
= utils_create_stream_file(stream
->chan
->pathname
, stream
->name
,
942 stream
->chan
->tracefile_size
, stream
->tracefile_count_current
,
943 stream
->uid
, stream
->gid
);
947 stream
->out_fd
= ret
;
948 stream
->tracefile_size_current
= 0;
951 if (stream
->output
== LTTNG_EVENT_MMAP
) {
952 /* get the len of the mmap region */
953 unsigned long mmap_len
;
955 ret
= kernctl_get_mmap_len(stream
->wait_fd
, &mmap_len
);
958 PERROR("kernctl_get_mmap_len");
961 stream
->mmap_len
= (size_t) mmap_len
;
963 stream
->mmap_base
= mmap(NULL
, stream
->mmap_len
, PROT_READ
,
964 MAP_PRIVATE
, stream
->wait_fd
, 0);
965 if (stream
->mmap_base
== MAP_FAILED
) {
966 PERROR("Error mmaping");
972 /* we return 0 to let the library handle the FD internally */
979 err
= close(stream
->out_fd
);
987 * Check if data is still being extracted from the buffers for a specific
988 * stream. Consumer data lock MUST be acquired before calling this function
989 * and the stream lock.
991 * Return 1 if the traced data are still getting read else 0 meaning that the
992 * data is available for trace viewer reading.
994 int lttng_kconsumer_data_pending(struct lttng_consumer_stream
*stream
)
1000 ret
= kernctl_get_next_subbuf(stream
->wait_fd
);
1002 /* There is still data so let's put back this subbuffer. */
1003 ret
= kernctl_put_subbuf(stream
->wait_fd
);
1005 ret
= 1; /* Data is pending */
1009 /* Data is NOT pending and ready to be read. */