2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 * 2012 - David Goulet <dgoulet@efficios.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License, version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 #ifndef LIB_CONSUMER_H
21 #define LIB_CONSUMER_H
27 #include <lttng/lttng.h>
29 #include <common/hashtable/hashtable.h>
30 #include <common/compat/fcntl.h>
31 #include <common/sessiond-comm/sessiond-comm.h>
34 * When the receiving thread dies, we need to have a way to make the polling
35 * thread exit eventually. If all FDs hang up (normal case when the
36 * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
37 * for whatever reason some FDs remain open, the consumer should still exit
40 * If the timeout is reached, it means that during this period no events
41 * occurred on the FDs so we need to force an exit. This case should not happen
42 * but it is a safety to ensure we won't block the consumer indefinitely.
44 * The value of 2 seconds is an arbitrary choice.
46 #define LTTNG_CONSUMER_POLL_TIMEOUT 2000
48 /* Commands for consumer */
49 enum lttng_consumer_command
{
50 LTTNG_CONSUMER_ADD_CHANNEL
,
51 LTTNG_CONSUMER_ADD_STREAM
,
52 /* pause, delete, active depending on fd state */
53 LTTNG_CONSUMER_UPDATE_STREAM
,
54 /* inform the consumer to quit when all fd has hang up */
56 LTTNG_CONSUMER_ADD_RELAYD_SOCKET
,
57 /* Inform the consumer to kill a specific relayd connection */
58 LTTNG_CONSUMER_DESTROY_RELAYD
,
59 /* Return to the sessiond if there is data pending for a session */
60 LTTNG_CONSUMER_DATA_AVAILABLE
,
63 /* State of each fd in consumer */
64 enum lttng_consumer_stream_state
{
65 LTTNG_CONSUMER_ACTIVE_STREAM
,
66 LTTNG_CONSUMER_PAUSE_STREAM
,
67 LTTNG_CONSUMER_DELETE_STREAM
,
70 enum lttng_consumer_type
{
71 LTTNG_CONSUMER_UNKNOWN
= 0,
72 LTTNG_CONSUMER_KERNEL
,
77 struct lttng_consumer_channel
{
78 struct lttng_ht_node_ulong node
;
80 uint64_t max_sb_size
; /* the subbuffer size for this channel */
81 int refcount
; /* Number of streams referencing this channel */
83 * The number of streams to receive initially. Used to guarantee that we do
84 * not destroy a channel before receiving all its associated streams.
86 unsigned int nb_init_streams
;
93 struct lttng_ust_shm_handle
*handle
;
98 /* Forward declaration for UST. */
99 struct lttng_ust_lib_ring_buffer
;
102 * Internal representation of the streams, sessiond_key is used to identify
105 struct lttng_consumer_stream
{
106 /* HT node used by the data_ht and metadata_ht */
107 struct lttng_ht_node_ulong node
;
108 /* HT node used in consumer_data.stream_list_ht */
109 struct lttng_ht_node_ulong node_session_id
;
110 struct lttng_consumer_channel
*chan
; /* associated channel */
112 * key is the key used by the session daemon to refer to the
113 * object in the consumer daemon.
118 int out_fd
; /* output file to write the data */
119 off_t out_fd_offset
; /* write position in the output file descriptor */
120 char path_name
[PATH_MAX
]; /* tracefile name */
121 enum lttng_consumer_stream_state state
;
125 enum lttng_event_output output
; /* splice or mmap */
129 struct lttng_ust_lib_ring_buffer
*buf
;
132 int hangup_flush_done
;
133 /* UID/GID of the user owning the session to which stream belongs */
136 /* Network sequence number. Indicating on which relayd socket it goes. */
138 /* Identify if the stream is the metadata */
139 unsigned int metadata_flag
;
140 /* Used when the stream is set for network streaming */
141 uint64_t relayd_stream_id
;
142 /* Next sequence number to use for trace packet */
143 uint64_t next_net_seq_num
;
145 * Lock to use the stream FDs since they are used between threads. Using
146 * this lock with network streaming, when using the control mutex of a
147 * consumer_relayd_sock_pair, make sure to acquire this lock BEFORE locking
148 * it and releasing it AFTER the control mutex unlock.
150 pthread_mutex_t lock
;
151 /* Tracing session id */
156 * Internal representation of a relayd socket pair.
158 struct consumer_relayd_sock_pair
{
159 /* Network sequence number. */
161 /* Number of stream associated with this relayd */
162 unsigned int refcount
;
165 * This flag indicates whether or not we should destroy this object. The
166 * destruction should ONLY occurs when this flag is set and the refcount is
169 unsigned int destroy_flag
;
172 * Mutex protecting the control socket to avoid out of order packets
173 * between threads sending data to the relayd. Since metadata data is sent
174 * over that socket, at least two sendmsg() are needed (header + data)
175 * creating a race for packets to overlap between threads using it.
177 pthread_mutex_t ctrl_sock_mutex
;
179 /* Control socket. Command and metadata are passed over it */
180 struct lttcomm_sock control_sock
;
183 * We don't need a mutex at this point since we only splice or write single
184 * large chunk of data with a header appended at the begining. Moreover,
185 * this socket is for now only used in a single thread.
187 struct lttcomm_sock data_sock
;
188 struct lttng_ht_node_ulong node
;
192 * UST consumer local data to the program. One or more instance per
195 struct lttng_consumer_local_data
{
197 * Function to call when data is available on a buffer.
198 * Returns the number of bytes read, or negative error value.
200 ssize_t (*on_buffer_ready
)(struct lttng_consumer_stream
*stream
,
201 struct lttng_consumer_local_data
*ctx
);
203 * function to call when we receive a new channel, it receives a
204 * newly allocated channel, depending on the return code of this
205 * function, the new channel will be handled by the application
209 * > 0 (success, FD is kept by application)
210 * == 0 (success, FD is left to library)
213 int (*on_recv_channel
)(struct lttng_consumer_channel
*channel
);
215 * function to call when we receive a new stream, it receives a
216 * newly allocated stream, depending on the return code of this
217 * function, the new stream will be handled by the application
221 * > 0 (success, FD is kept by application)
222 * == 0 (success, FD is left to library)
225 int (*on_recv_stream
)(struct lttng_consumer_stream
*stream
);
227 * function to call when a stream is getting updated by the session
228 * daemon, this function receives the sessiond key and the new
229 * state, depending on the return code of this function the
230 * update of state for the stream is handled by the application
234 * > 0 (success, FD is kept by application)
235 * == 0 (success, FD is left to library)
238 int (*on_update_stream
)(int sessiond_key
, uint32_t state
);
239 /* socket to communicate errors with sessiond */
240 int consumer_error_socket
;
241 /* socket to exchange commands with sessiond */
242 char *consumer_command_sock_path
;
243 /* communication with splice */
244 int consumer_thread_pipe
[2];
245 int consumer_splice_metadata_pipe
[2];
246 /* Data stream poll thread pipe. To transfer data stream to the thread */
247 int consumer_data_pipe
[2];
248 /* to let the signal handler wake up the fd receiver thread */
249 int consumer_should_quit
[2];
250 /* Metadata poll thread pipe. Transfer metadata stream to it */
251 int consumer_metadata_pipe
[2];
255 * Library-level data. One instance per process.
257 struct lttng_consumer_global_data
{
259 * At this time, this lock is used to ensure coherence between the count
260 * and number of element in the hash table. It's also a protection for
261 * concurrent read/write between threads.
263 * XXX: We need to see if this lock is still needed with the lockless RCU
266 pthread_mutex_t lock
;
269 * Number of streams in the data stream hash table declared outside.
270 * Protected by consumer_data.lock.
274 /* Channel hash table protected by consumer_data.lock. */
275 struct lttng_ht
*channel_ht
;
277 * Flag specifying if the local array of FDs needs update in the
278 * poll function. Protected by consumer_data.lock.
280 unsigned int need_update
;
281 enum lttng_consumer_type type
;
284 * Relayd socket(s) hashtable indexed by network sequence number. Each
285 * stream has an index which associate the right relayd socket to use.
287 struct lttng_ht
*relayd_ht
;
290 * This hash table contains all streams (metadata and data) indexed by
291 * session id. In other words, the ht is indexed by session id and each
292 * bucket contains the list of associated streams.
294 * This HT uses the "node_session_id" of the consumer stream.
296 struct lttng_ht
*stream_list_ht
;
299 /* Defined in consumer.c and coupled with explanations */
300 extern struct lttng_ht
*metadata_ht
;
301 extern struct lttng_ht
*data_ht
;
304 * Init consumer data structures.
306 extern void lttng_consumer_init(void);
309 * Set the error socket for communication with a session daemon.
311 extern void lttng_consumer_set_error_sock(
312 struct lttng_consumer_local_data
*ctx
, int sock
);
315 * Set the command socket path for communication with a session daemon.
317 extern void lttng_consumer_set_command_sock_path(
318 struct lttng_consumer_local_data
*ctx
, char *sock
);
321 * Send return code to session daemon.
323 * Returns the return code of sendmsg : the number of bytes transmitted or -1
326 extern int lttng_consumer_send_error(
327 struct lttng_consumer_local_data
*ctx
, int cmd
);
330 * Called from signal handler to ensure a clean exit.
332 extern void lttng_consumer_should_exit(
333 struct lttng_consumer_local_data
*ctx
);
336 * Cleanup the daemon's socket on exit.
338 extern void lttng_consumer_cleanup(void);
341 * Flush pending writes to trace output disk file.
343 extern void lttng_consumer_sync_trace_file(
344 struct lttng_consumer_stream
*stream
, off_t orig_offset
);
347 * Poll on the should_quit pipe and the command socket return -1 on error and
348 * should exit, 0 if data is available on the command socket
350 extern int lttng_consumer_poll_socket(struct pollfd
*kconsumer_sockpoll
);
352 extern struct lttng_consumer_stream
*consumer_allocate_stream(
353 int channel_key
, int stream_key
,
354 int shm_fd
, int wait_fd
,
355 enum lttng_consumer_stream_state state
,
357 enum lttng_event_output output
,
358 const char *path_name
,
365 extern void consumer_del_stream(struct lttng_consumer_stream
*stream
,
366 struct lttng_ht
*ht
);
367 extern void consumer_del_metadata_stream(struct lttng_consumer_stream
*stream
,
368 struct lttng_ht
*ht
);
369 extern void consumer_del_channel(struct lttng_consumer_channel
*channel
);
370 extern struct lttng_consumer_channel
*consumer_allocate_channel(
372 int shm_fd
, int wait_fd
,
374 uint64_t max_sb_size
,
375 unsigned int nb_init_streams
);
376 int consumer_add_channel(struct lttng_consumer_channel
*channel
);
378 /* lttng-relayd consumer command */
379 struct consumer_relayd_sock_pair
*consumer_allocate_relayd_sock_pair(
381 struct consumer_relayd_sock_pair
*consumer_find_relayd(int key
);
382 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream
*stream
,
384 void consumer_steal_stream_key(int key
, struct lttng_ht
*ht
);
386 extern struct lttng_consumer_local_data
*lttng_consumer_create(
387 enum lttng_consumer_type type
,
388 ssize_t (*buffer_ready
)(struct lttng_consumer_stream
*stream
,
389 struct lttng_consumer_local_data
*ctx
),
390 int (*recv_channel
)(struct lttng_consumer_channel
*channel
),
391 int (*recv_stream
)(struct lttng_consumer_stream
*stream
),
392 int (*update_stream
)(int sessiond_key
, uint32_t state
));
393 extern void lttng_consumer_destroy(struct lttng_consumer_local_data
*ctx
);
394 extern ssize_t
lttng_consumer_on_read_subbuffer_mmap(
395 struct lttng_consumer_local_data
*ctx
,
396 struct lttng_consumer_stream
*stream
, unsigned long len
,
397 unsigned long padding
);
398 extern ssize_t
lttng_consumer_on_read_subbuffer_splice(
399 struct lttng_consumer_local_data
*ctx
,
400 struct lttng_consumer_stream
*stream
, unsigned long len
,
401 unsigned long padding
);
402 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data
*ctx
,
403 struct lttng_consumer_stream
*stream
);
404 extern int lttng_consumer_get_produced_snapshot(
405 struct lttng_consumer_local_data
*ctx
,
406 struct lttng_consumer_stream
*stream
,
408 extern void *consumer_thread_metadata_poll(void *data
);
409 extern void *consumer_thread_data_poll(void *data
);
410 extern void *consumer_thread_sessiond_poll(void *data
);
411 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
412 int sock
, struct pollfd
*consumer_sockpoll
);
414 ssize_t
lttng_consumer_read_subbuffer(struct lttng_consumer_stream
*stream
,
415 struct lttng_consumer_local_data
*ctx
);
416 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream
*stream
);
417 int consumer_add_relayd_socket(int net_seq_idx
, int sock_type
,
418 struct lttng_consumer_local_data
*ctx
, int sock
,
419 struct pollfd
*consumer_sockpoll
, struct lttcomm_sock
*relayd_sock
);
420 void consumer_flag_relayd_for_destroy(
421 struct consumer_relayd_sock_pair
*relayd
);
422 int consumer_data_available(uint64_t id
);
424 #endif /* LIB_CONSUMER_H */