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
,
61 /* State of each fd in consumer */
62 enum lttng_consumer_stream_state
{
63 LTTNG_CONSUMER_ACTIVE_STREAM
,
64 LTTNG_CONSUMER_PAUSE_STREAM
,
65 LTTNG_CONSUMER_DELETE_STREAM
,
68 enum lttng_consumer_type
{
69 LTTNG_CONSUMER_UNKNOWN
= 0,
70 LTTNG_CONSUMER_KERNEL
,
75 struct lttng_consumer_channel
{
76 struct lttng_ht_node_ulong node
;
78 uint64_t max_sb_size
; /* the subbuffer size for this channel */
79 int refcount
; /* Number of streams referencing this channel */
85 struct lttng_ust_shm_handle
*handle
;
90 /* Forward declaration for UST. */
91 struct lttng_ust_lib_ring_buffer
;
94 * Internal representation of the streams, sessiond_key is used to identify
97 struct lttng_consumer_stream
{
98 struct lttng_ht_node_ulong node
;
99 struct lttng_ht_node_ulong waitfd_node
;
100 struct lttng_consumer_channel
*chan
; /* associated channel */
102 * key is the key used by the session daemon to refer to the
103 * object in the consumer daemon.
108 int out_fd
; /* output file to write the data */
109 off_t out_fd_offset
; /* write position in the output file descriptor */
110 char path_name
[PATH_MAX
]; /* tracefile name */
111 enum lttng_consumer_stream_state state
;
115 enum lttng_event_output output
; /* splice or mmap */
119 struct lttng_ust_lib_ring_buffer
*buf
;
122 int hangup_flush_done
;
123 /* UID/GID of the user owning the session to which stream belongs */
126 /* Network sequence number. Indicating on which relayd socket it goes. */
128 /* Identify if the stream is the metadata */
129 unsigned int metadata_flag
;
130 /* Used when the stream is set for network streaming */
131 uint64_t relayd_stream_id
;
132 /* Next sequence number to use for trace packet */
133 uint64_t next_net_seq_num
;
137 * Internal representation of a relayd socket pair.
139 struct consumer_relayd_sock_pair
{
140 /* Network sequence number. */
142 /* Number of stream associated with this relayd */
143 unsigned int refcount
;
146 * This flag indicates whether or not we should destroy this object. The
147 * destruction should ONLY occurs when this flag is set and the refcount is
150 unsigned int destroy_flag
;
153 * Mutex protecting the control socket to avoid out of order packets
154 * between threads sending data to the relayd. Since metadata data is sent
155 * over that socket, at least two sendmsg() are needed (header + data)
156 * creating a race for packets to overlap between threads using it.
158 pthread_mutex_t ctrl_sock_mutex
;
160 /* Control socket. Command and metadata are passed over it */
161 struct lttcomm_sock control_sock
;
164 * We don't need a mutex at this point since we only splice or write single
165 * large chunk of data with a header appended at the begining. Moreover,
166 * this socket is for now only used in a single thread.
168 struct lttcomm_sock data_sock
;
169 struct lttng_ht_node_ulong node
;
173 * UST consumer local data to the program. One or more instance per
176 struct lttng_consumer_local_data
{
178 * Function to call when data is available on a buffer.
179 * Returns the number of bytes read, or negative error value.
181 ssize_t (*on_buffer_ready
)(struct lttng_consumer_stream
*stream
,
182 struct lttng_consumer_local_data
*ctx
);
184 * function to call when we receive a new channel, it receives a
185 * newly allocated channel, depending on the return code of this
186 * function, the new channel will be handled by the application
190 * > 0 (success, FD is kept by application)
191 * == 0 (success, FD is left to library)
194 int (*on_recv_channel
)(struct lttng_consumer_channel
*channel
);
196 * function to call when we receive a new stream, it receives a
197 * newly allocated stream, depending on the return code of this
198 * function, the new stream will be handled by the application
202 * > 0 (success, FD is kept by application)
203 * == 0 (success, FD is left to library)
206 int (*on_recv_stream
)(struct lttng_consumer_stream
*stream
);
208 * function to call when a stream is getting updated by the session
209 * daemon, this function receives the sessiond key and the new
210 * state, depending on the return code of this function the
211 * update of state for the stream is handled by the application
215 * > 0 (success, FD is kept by application)
216 * == 0 (success, FD is left to library)
219 int (*on_update_stream
)(int sessiond_key
, uint32_t state
);
220 /* socket to communicate errors with sessiond */
221 int consumer_error_socket
;
222 /* socket to exchange commands with sessiond */
223 char *consumer_command_sock_path
;
224 /* communication with splice */
225 int consumer_thread_pipe
[2];
226 int consumer_splice_metadata_pipe
[2];
227 /* pipe to wake the poll thread when necessary */
228 int consumer_poll_pipe
[2];
229 /* to let the signal handler wake up the fd receiver thread */
230 int consumer_should_quit
[2];
231 /* Metadata poll thread pipe. Transfer metadata stream to it */
232 int consumer_metadata_pipe
[2];
236 * Library-level data. One instance per process.
238 struct lttng_consumer_global_data
{
240 * At this time, this lock is used to ensure coherence between the count
241 * and number of element in the hash table. It's also a protection for
242 * concurrent read/write between threads.
244 * XXX: We need to see if this lock is still needed with the lockless RCU
247 pthread_mutex_t lock
;
250 * Number of streams in the hash table. Protected by consumer_data.lock.
254 * Hash tables of streams and channels. Protected by consumer_data.lock.
256 struct lttng_ht
*stream_ht
;
257 struct lttng_ht
*channel_ht
;
259 * Flag specifying if the local array of FDs needs update in the
260 * poll function. Protected by consumer_data.lock.
262 unsigned int need_update
;
263 enum lttng_consumer_type type
;
266 * Relayd socket(s) hashtable indexed by network sequence number. Each
267 * stream has an index which associate the right relayd socket to use.
269 struct lttng_ht
*relayd_ht
;
273 * Init consumer data structures.
275 extern void lttng_consumer_init(void);
278 * Set the error socket for communication with a session daemon.
280 extern void lttng_consumer_set_error_sock(
281 struct lttng_consumer_local_data
*ctx
, int sock
);
284 * Set the command socket path for communication with a session daemon.
286 extern void lttng_consumer_set_command_sock_path(
287 struct lttng_consumer_local_data
*ctx
, char *sock
);
290 * Send return code to session daemon.
292 * Returns the return code of sendmsg : the number of bytes transmitted or -1
295 extern int lttng_consumer_send_error(
296 struct lttng_consumer_local_data
*ctx
, int cmd
);
299 * Called from signal handler to ensure a clean exit.
301 extern void lttng_consumer_should_exit(
302 struct lttng_consumer_local_data
*ctx
);
305 * Cleanup the daemon's socket on exit.
307 extern void lttng_consumer_cleanup(void);
310 * Flush pending writes to trace output disk file.
312 extern void lttng_consumer_sync_trace_file(
313 struct lttng_consumer_stream
*stream
, off_t orig_offset
);
316 * Poll on the should_quit pipe and the command socket return -1 on error and
317 * should exit, 0 if data is available on the command socket
319 extern int lttng_consumer_poll_socket(struct pollfd
*kconsumer_sockpoll
);
321 extern int consumer_update_poll_array(
322 struct lttng_consumer_local_data
*ctx
, struct pollfd
**pollfd
,
323 struct lttng_consumer_stream
**local_consumer_streams
);
325 extern struct lttng_consumer_stream
*consumer_allocate_stream(
326 int channel_key
, int stream_key
,
327 int shm_fd
, int wait_fd
,
328 enum lttng_consumer_stream_state state
,
330 enum lttng_event_output output
,
331 const char *path_name
,
336 extern int consumer_add_stream(struct lttng_consumer_stream
*stream
);
337 extern void consumer_del_stream(struct lttng_consumer_stream
*stream
);
338 extern void consumer_change_stream_state(int stream_key
,
339 enum lttng_consumer_stream_state state
);
340 extern void consumer_del_channel(struct lttng_consumer_channel
*channel
);
341 extern struct lttng_consumer_channel
*consumer_allocate_channel(
343 int shm_fd
, int wait_fd
,
345 uint64_t max_sb_size
);
346 int consumer_add_channel(struct lttng_consumer_channel
*channel
);
348 /* lttng-relayd consumer command */
349 int consumer_add_relayd(struct consumer_relayd_sock_pair
*relayd
);
350 struct consumer_relayd_sock_pair
*consumer_allocate_relayd_sock_pair(
352 struct consumer_relayd_sock_pair
*consumer_find_relayd(int key
);
353 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream
*stream
,
355 void consumer_destroy_relayd(struct consumer_relayd_sock_pair
*relayd
);
357 extern struct lttng_consumer_local_data
*lttng_consumer_create(
358 enum lttng_consumer_type type
,
359 ssize_t (*buffer_ready
)(struct lttng_consumer_stream
*stream
,
360 struct lttng_consumer_local_data
*ctx
),
361 int (*recv_channel
)(struct lttng_consumer_channel
*channel
),
362 int (*recv_stream
)(struct lttng_consumer_stream
*stream
),
363 int (*update_stream
)(int sessiond_key
, uint32_t state
));
364 extern void lttng_consumer_destroy(struct lttng_consumer_local_data
*ctx
);
365 extern ssize_t
lttng_consumer_on_read_subbuffer_mmap(
366 struct lttng_consumer_local_data
*ctx
,
367 struct lttng_consumer_stream
*stream
, unsigned long len
);
368 extern ssize_t
lttng_consumer_on_read_subbuffer_splice(
369 struct lttng_consumer_local_data
*ctx
,
370 struct lttng_consumer_stream
*stream
, unsigned long len
);
371 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data
*ctx
,
372 struct lttng_consumer_stream
*stream
);
373 extern int lttng_consumer_get_produced_snapshot(
374 struct lttng_consumer_local_data
*ctx
,
375 struct lttng_consumer_stream
*stream
,
377 extern void *lttng_consumer_thread_poll_fds(void *data
);
378 extern void *lttng_consumer_thread_receive_fds(void *data
);
379 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
380 int sock
, struct pollfd
*consumer_sockpoll
);
382 ssize_t
lttng_consumer_read_subbuffer(struct lttng_consumer_stream
*stream
,
383 struct lttng_consumer_local_data
*ctx
);
384 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream
*stream
);
385 int consumer_add_relayd_socket(int net_seq_idx
, int sock_type
,
386 struct lttng_consumer_local_data
*ctx
, int sock
,
387 struct pollfd
*consumer_sockpoll
, struct lttcomm_sock
*relayd_sock
);
388 void consumer_flag_relayd_for_destroy(
389 struct consumer_relayd_sock_pair
*relayd
);
391 #endif /* LIB_CONSUMER_H */