2 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
3 * Copyright (C) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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
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.
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.
20 #ifndef _LTTNG_CONSUMER_H
21 #define _LTTNG_CONSUMER_H
27 #include <lttng/lttng.h>
29 #include <common/hashtable/hashtable.h>
30 #include <common/compat/fcntl.h>
33 * When the receiving thread dies, we need to have a way to make the polling
34 * thread exit eventually. If all FDs hang up (normal case when the
35 * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
36 * for whatever reason some FDs remain open, the consumer should still exit
39 * If the timeout is reached, it means that during this period no events
40 * occurred on the FDs so we need to force an exit. This case should not happen
41 * but it is a safety to ensure we won't block the consumer indefinitely.
43 * The value of 2 seconds is an arbitrary choice.
45 #define LTTNG_CONSUMER_POLL_TIMEOUT 2000
47 /* Commands for consumer */
48 enum lttng_consumer_command
{
49 LTTNG_CONSUMER_ADD_CHANNEL
,
50 LTTNG_CONSUMER_ADD_STREAM
,
51 /* pause, delete, active depending on fd state */
52 LTTNG_CONSUMER_UPDATE_STREAM
,
53 /* inform the consumer to quit when all fd has hang up */
57 /* State of each fd in consumer */
58 enum lttng_consumer_stream_state
{
59 LTTNG_CONSUMER_ACTIVE_STREAM
,
60 LTTNG_CONSUMER_PAUSE_STREAM
,
61 LTTNG_CONSUMER_DELETE_STREAM
,
64 enum lttng_consumer_type
{
65 LTTNG_CONSUMER_UNKNOWN
= 0,
66 LTTNG_CONSUMER_KERNEL
,
71 struct lttng_consumer_channel
{
72 struct lttng_ht_node_ulong node
;
74 uint64_t max_sb_size
; /* the subbuffer size for this channel */
75 int refcount
; /* Number of streams referencing this channel */
81 struct lttng_ust_shm_handle
*handle
;
87 /* Forward declaration for UST. */
88 struct lttng_ust_lib_ring_buffer
;
91 * Internal representation of the streams, sessiond_key is used to identify
94 struct lttng_consumer_stream
{
95 struct lttng_ht_node_ulong node
;
96 struct lttng_consumer_channel
*chan
; /* associated channel */
98 * key is the key used by the session daemon to refer to the
99 * object in the consumer daemon.
104 int out_fd
; /* output file to write the data */
105 off_t out_fd_offset
; /* write position in the output file descriptor */
106 char path_name
[PATH_MAX
]; /* tracefile name */
107 enum lttng_consumer_stream_state state
;
111 enum lttng_event_output output
; /* splice or mmap */
115 struct lttng_ust_lib_ring_buffer
*buf
;
118 int hangup_flush_done
;
119 /* UID/GID of the user owning the session to which stream belongs */
125 * UST consumer local data to the program. One or more instance per
128 struct lttng_consumer_local_data
{
130 * Function to call when data is available on a buffer.
131 * Returns the number of bytes read, or negative error value.
133 ssize_t (*on_buffer_ready
)(struct lttng_consumer_stream
*stream
,
134 struct lttng_consumer_local_data
*ctx
);
136 * function to call when we receive a new channel, it receives a
137 * newly allocated channel, depending on the return code of this
138 * function, the new channel will be handled by the application
142 * > 0 (success, FD is kept by application)
143 * == 0 (success, FD is left to library)
146 int (*on_recv_channel
)(struct lttng_consumer_channel
*channel
);
148 * function to call when we receive a new stream, it receives a
149 * newly allocated stream, depending on the return code of this
150 * function, the new stream will be handled by the application
154 * > 0 (success, FD is kept by application)
155 * == 0 (success, FD is left to library)
158 int (*on_recv_stream
)(struct lttng_consumer_stream
*stream
);
160 * function to call when a stream is getting updated by the session
161 * daemon, this function receives the sessiond key and the new
162 * state, depending on the return code of this function the
163 * update of state for the stream is handled by the application
167 * > 0 (success, FD is kept by application)
168 * == 0 (success, FD is left to library)
171 int (*on_update_stream
)(int sessiond_key
, uint32_t state
);
172 /* socket to communicate errors with sessiond */
173 int consumer_error_socket
;
174 /* socket to exchange commands with sessiond */
175 char *consumer_command_sock_path
;
176 /* communication with splice */
177 int consumer_thread_pipe
[2];
178 /* pipe to wake the poll thread when necessary */
179 int consumer_poll_pipe
[2];
180 /* to let the signal handler wake up the fd receiver thread */
181 int consumer_should_quit
[2];
185 * Library-level data. One instance per process.
187 struct lttng_consumer_global_data
{
190 * At this time, this lock is used to ensure coherence between the count
191 * and number of element in the hash table. It's also a protection for
192 * concurrent read/write between threads.
194 * XXX: We need to see if this lock is still needed with the lockless RCU
197 pthread_mutex_t lock
;
200 * Number of streams in the hash table. Protected by consumer_data.lock.
204 * Hash tables of streams and channels. Protected by consumer_data.lock.
206 struct lttng_ht
*stream_ht
;
207 struct lttng_ht
*channel_ht
;
209 * Flag specifying if the local array of FDs needs update in the
210 * poll function. Protected by consumer_data.lock.
212 unsigned int need_update
;
213 enum lttng_consumer_type type
;
217 * Init consumer data structures.
219 extern void lttng_consumer_init(void);
222 * Set the error socket for communication with a session daemon.
224 extern void lttng_consumer_set_error_sock(
225 struct lttng_consumer_local_data
*ctx
, int sock
);
228 * Set the command socket path for communication with a session daemon.
230 extern void lttng_consumer_set_command_sock_path(
231 struct lttng_consumer_local_data
*ctx
, char *sock
);
234 * Send return code to session daemon.
236 * Returns the return code of sendmsg : the number of bytes transmitted or -1
239 extern int lttng_consumer_send_error(
240 struct lttng_consumer_local_data
*ctx
, int cmd
);
243 * Called from signal handler to ensure a clean exit.
245 extern void lttng_consumer_should_exit(
246 struct lttng_consumer_local_data
*ctx
);
249 * Cleanup the daemon's socket on exit.
251 extern void lttng_consumer_cleanup(void);
254 * Flush pending writes to trace output disk file.
256 extern void lttng_consumer_sync_trace_file(
257 struct lttng_consumer_stream
*stream
, off_t orig_offset
);
260 * Poll on the should_quit pipe and the command socket return -1 on error and
261 * should exit, 0 if data is available on the command socket
263 extern int lttng_consumer_poll_socket(struct pollfd
*kconsumer_sockpoll
);
265 extern int consumer_update_poll_array(
266 struct lttng_consumer_local_data
*ctx
, struct pollfd
**pollfd
,
267 struct lttng_consumer_stream
**local_consumer_streams
);
269 extern struct lttng_consumer_stream
*consumer_allocate_stream(
270 int channel_key
, int stream_key
,
271 int shm_fd
, int wait_fd
,
272 enum lttng_consumer_stream_state state
,
274 enum lttng_event_output output
,
275 const char *path_name
,
278 extern int consumer_add_stream(struct lttng_consumer_stream
*stream
);
279 extern void consumer_del_stream(struct lttng_consumer_stream
*stream
);
280 extern void consumer_change_stream_state(int stream_key
,
281 enum lttng_consumer_stream_state state
);
282 extern void consumer_del_channel(struct lttng_consumer_channel
*channel
);
283 extern struct lttng_consumer_channel
*consumer_allocate_channel(
285 int shm_fd
, int wait_fd
,
287 uint64_t max_sb_size
);
288 int consumer_add_channel(struct lttng_consumer_channel
*channel
);
290 extern struct lttng_consumer_local_data
*lttng_consumer_create(
291 enum lttng_consumer_type type
,
292 ssize_t (*buffer_ready
)(struct lttng_consumer_stream
*stream
,
293 struct lttng_consumer_local_data
*ctx
),
294 int (*recv_channel
)(struct lttng_consumer_channel
*channel
),
295 int (*recv_stream
)(struct lttng_consumer_stream
*stream
),
296 int (*update_stream
)(int sessiond_key
, uint32_t state
));
297 extern void lttng_consumer_destroy(struct lttng_consumer_local_data
*ctx
);
298 extern ssize_t
lttng_consumer_on_read_subbuffer_mmap(
299 struct lttng_consumer_local_data
*ctx
,
300 struct lttng_consumer_stream
*stream
, unsigned long len
);
301 extern ssize_t
lttng_consumer_on_read_subbuffer_splice(
302 struct lttng_consumer_local_data
*ctx
,
303 struct lttng_consumer_stream
*stream
, unsigned long len
);
304 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data
*ctx
,
305 struct lttng_consumer_stream
*stream
);
306 extern int lttng_consumer_get_produced_snapshot(
307 struct lttng_consumer_local_data
*ctx
,
308 struct lttng_consumer_stream
*stream
,
310 extern void *lttng_consumer_thread_poll_fds(void *data
);
311 extern void *lttng_consumer_thread_receive_fds(void *data
);
312 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
313 int sock
, struct pollfd
*consumer_sockpoll
);
315 ssize_t
lttng_consumer_read_subbuffer(struct lttng_consumer_stream
*stream
,
316 struct lttng_consumer_local_data
*ctx
);
317 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream
*stream
);
319 #endif /* _LTTNG_CONSUMER_H */