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
25 #include <urcu/list.h>
26 #include <lttng/lttng.h>
29 * When the receiving thread dies, we need to have a way to make the polling
30 * thread exit eventually. If all FDs hang up (normal case when the
31 * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
32 * for whatever reason some FDs remain open, the consumer should still exit
35 * If the timeout is reached, it means that during this period no events
36 * occurred on the FDs so we need to force an exit. This case should not happen
37 * but it is a safety to ensure we won't block the consumer indefinitely.
39 * The value of 2 seconds is an arbitrary choice.
41 #define LTTNG_CONSUMER_POLL_TIMEOUT 2000
43 /* Commands for consumer */
44 enum lttng_consumer_command
{
45 LTTNG_CONSUMER_ADD_CHANNEL
,
46 LTTNG_CONSUMER_ADD_STREAM
,
47 /* pause, delete, active depending on fd state */
48 LTTNG_CONSUMER_UPDATE_STREAM
,
49 /* inform the consumer to quit when all fd has hang up */
53 /* State of each fd in consumer */
54 enum lttng_consumer_stream_state
{
55 LTTNG_CONSUMER_ACTIVE_STREAM
,
56 LTTNG_CONSUMER_PAUSE_STREAM
,
57 LTTNG_CONSUMER_DELETE_STREAM
,
60 struct lttng_consumer_channel_list
{
61 struct cds_list_head head
;
64 struct lttng_consumer_stream_list
{
65 struct cds_list_head head
;
68 enum lttng_consumer_type
{
69 LTTNG_CONSUMER_UNKNOWN
= 0,
70 LTTNG_CONSUMER_KERNEL
,
74 struct lttng_consumer_channel
{
75 struct cds_list_head list
;
77 uint64_t max_sb_size
; /* the subbuffer size for this channel */
78 int refcount
; /* Number of streams referencing this channel */
84 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 cds_list_head list
;
99 struct lttng_consumer_channel
*chan
; /* associated channel */
101 * key is the key used by the session daemon to refer to the
102 * object in the consumer daemon.
107 int out_fd
; /* output file to write the data */
108 off_t out_fd_offset
; /* write position in the output file descriptor */
109 char path_name
[PATH_MAX
]; /* tracefile name */
110 enum lttng_consumer_stream_state state
;
114 enum lttng_event_output output
; /* splice or mmap */
118 struct lttng_ust_lib_ring_buffer
*buf
;
123 * UST consumer local data to the program. One or more instance per
126 struct lttng_consumer_local_data
{
127 /* function to call when data is available on a buffer */
128 int (*on_buffer_ready
)(struct lttng_consumer_stream
*stream
);
130 * function to call when we receive a new channel, it receives a
131 * newly allocated channel, depending on the return code of this
132 * function, the new channel will be handled by the application
136 * > 0 (success, FD is kept by application)
137 * == 0 (success, FD is left to library)
140 int (*on_recv_channel
)(struct lttng_consumer_channel
*channel
);
142 * function to call when we receive a new stream, it receives a
143 * newly allocated stream, depending on the return code of this
144 * function, the new stream will be handled by the application
148 * > 0 (success, FD is kept by application)
149 * == 0 (success, FD is left to library)
152 int (*on_recv_stream
)(struct lttng_consumer_stream
*stream
);
154 * function to call when a stream is getting updated by the session
155 * daemon, this function receives the sessiond key and the new
156 * state, depending on the return code of this function the
157 * update of state for the stream is handled by the application
161 * > 0 (success, FD is kept by application)
162 * == 0 (success, FD is left to library)
165 int (*on_update_stream
)(int sessiond_key
, uint32_t state
);
166 /* socket to communicate errors with sessiond */
167 int consumer_error_socket
;
168 /* socket to exchange commands with sessiond */
169 char *consumer_command_sock_path
;
170 /* communication with splice */
171 int consumer_thread_pipe
[2];
172 /* pipe to wake the poll thread when necessary */
173 int consumer_poll_pipe
[2];
174 /* to let the signal handler wake up the fd receiver thread */
175 int consumer_should_quit
[2];
179 * Library-level data. One instance per process.
181 struct lttng_consumer_global_data
{
183 * consumer_data.lock protects consumer_data.fd_list,
184 * consumer_data.stream_count, and consumer_data.need_update. It
185 * ensures the count matches the number of items in the fd_list.
186 * It ensures the list updates *always* trigger an fd_array
187 * update (therefore need to make list update vs
188 * consumer_data.need_update flag update atomic, and also flag
189 * read, fd array and flag clear atomic).
191 pthread_mutex_t lock
;
193 * Number of streams in the list below. Protected by
194 * consumer_data.lock.
198 * Lists of streams and channels. Protected by consumer_data.lock.
200 struct lttng_consumer_stream_list stream_list
;
201 struct lttng_consumer_channel_list channel_list
;
203 * Flag specifying if the local array of FDs needs update in the
204 * poll function. Protected by consumer_data.lock.
206 unsigned int need_update
;
207 enum lttng_consumer_type type
;
211 * Set the error socket for communication with a session daemon.
213 extern void lttng_consumer_set_error_sock(
214 struct lttng_consumer_local_data
*ctx
, int sock
);
217 * Set the command socket path for communication with a session daemon.
219 extern void lttng_consumer_set_command_sock_path(
220 struct lttng_consumer_local_data
*ctx
, char *sock
);
223 * Send return code to session daemon.
225 * Returns the return code of sendmsg : the number of bytes transmitted or -1
228 extern int lttng_consumer_send_error(
229 struct lttng_consumer_local_data
*ctx
, int cmd
);
232 * Called from signal handler to ensure a clean exit.
234 extern void lttng_consumer_should_exit(
235 struct lttng_consumer_local_data
*ctx
);
238 * Cleanup the daemon's socket on exit.
240 extern void lttng_consumer_cleanup(void);
243 * Flush pending writes to trace output disk file.
245 extern void lttng_consumer_sync_trace_file(
246 struct lttng_consumer_stream
*stream
, off_t orig_offset
);
249 * Poll on the should_quit pipe and the command socket return -1 on error and
250 * should exit, 0 if data is available on the command socket
252 extern int lttng_consumer_poll_socket(struct pollfd
*kconsumer_sockpoll
);
254 extern int consumer_update_poll_array(
255 struct lttng_consumer_local_data
*ctx
, struct pollfd
**pollfd
,
256 struct lttng_consumer_stream
**local_consumer_streams
);
258 extern struct lttng_consumer_stream
*consumer_allocate_stream(
259 int channel_key
, int stream_key
,
260 int shm_fd
, int wait_fd
,
261 enum lttng_consumer_stream_state state
,
263 enum lttng_event_output output
,
264 const char *path_name
);
265 extern int consumer_add_stream(struct lttng_consumer_stream
*stream
);
266 extern void consumer_del_stream(struct lttng_consumer_stream
*stream
);
267 extern void consumer_change_stream_state(int stream_key
,
268 enum lttng_consumer_stream_state state
);
269 extern void consumer_del_channel(struct lttng_consumer_channel
*channel
);
270 extern struct lttng_consumer_channel
*consumer_allocate_channel(
272 int shm_fd
, int wait_fd
,
274 uint64_t max_sb_size
);
275 int consumer_add_channel(struct lttng_consumer_channel
*channel
);
277 extern struct lttng_consumer_local_data
*lttng_consumer_create(
278 enum lttng_consumer_type type
,
279 int (*buffer_ready
)(struct lttng_consumer_stream
*stream
),
280 int (*recv_channel
)(struct lttng_consumer_channel
*channel
),
281 int (*recv_stream
)(struct lttng_consumer_stream
*stream
),
282 int (*update_stream
)(int sessiond_key
, uint32_t state
));
283 extern void lttng_consumer_destroy(struct lttng_consumer_local_data
*ctx
);
284 extern int lttng_consumer_on_read_subbuffer_mmap(
285 struct lttng_consumer_local_data
*ctx
,
286 struct lttng_consumer_stream
*stream
, unsigned long len
);
287 extern int lttng_consumer_on_read_subbuffer_splice(
288 struct lttng_consumer_local_data
*ctx
,
289 struct lttng_consumer_stream
*stream
, unsigned long len
);
290 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data
*ctx
,
291 struct lttng_consumer_stream
*stream
);
292 extern int lttng_consumer_get_produced_snapshot(
293 struct lttng_consumer_local_data
*ctx
,
294 struct lttng_consumer_stream
*stream
,
296 extern void *lttng_consumer_thread_poll_fds(void *data
);
297 extern void *lttng_consumer_thread_receive_fds(void *data
);
298 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
299 int sock
, struct pollfd
*consumer_sockpoll
);
301 #endif /* _LTTNG_CONSUMER_H */