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 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, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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.
19 #ifndef _LTTNG_CONSUMER_H
20 #define _LTTNG_CONSUMER_H
26 #include <lttng/lttng.h>
28 #include <common/hashtable/hashtable.h>
29 #include <common/compat/fcntl.h>
32 * When the receiving thread dies, we need to have a way to make the polling
33 * thread exit eventually. If all FDs hang up (normal case when the
34 * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
35 * for whatever reason some FDs remain open, the consumer should still exit
38 * If the timeout is reached, it means that during this period no events
39 * occurred on the FDs so we need to force an exit. This case should not happen
40 * but it is a safety to ensure we won't block the consumer indefinitely.
42 * The value of 2 seconds is an arbitrary choice.
44 #define LTTNG_CONSUMER_POLL_TIMEOUT 2000
46 /* Commands for consumer */
47 enum lttng_consumer_command
{
48 LTTNG_CONSUMER_ADD_CHANNEL
,
49 LTTNG_CONSUMER_ADD_STREAM
,
50 /* pause, delete, active depending on fd state */
51 LTTNG_CONSUMER_UPDATE_STREAM
,
52 /* inform the consumer to quit when all fd has hang up */
56 /* State of each fd in consumer */
57 enum lttng_consumer_stream_state
{
58 LTTNG_CONSUMER_ACTIVE_STREAM
,
59 LTTNG_CONSUMER_PAUSE_STREAM
,
60 LTTNG_CONSUMER_DELETE_STREAM
,
63 enum lttng_consumer_type
{
64 LTTNG_CONSUMER_UNKNOWN
= 0,
65 LTTNG_CONSUMER_KERNEL
,
70 struct lttng_consumer_channel
{
71 struct lttng_ht_node_ulong node
;
73 uint64_t max_sb_size
; /* the subbuffer size for this channel */
74 int refcount
; /* Number of streams referencing this channel */
80 struct lttng_ust_shm_handle
*handle
;
86 /* Forward declaration for UST. */
87 struct lttng_ust_lib_ring_buffer
;
90 * Internal representation of the streams, sessiond_key is used to identify
93 struct lttng_consumer_stream
{
94 struct lttng_ht_node_ulong node
;
95 struct lttng_consumer_channel
*chan
; /* associated channel */
97 * key is the key used by the session daemon to refer to the
98 * object in the consumer daemon.
103 int out_fd
; /* output file to write the data */
104 off_t out_fd_offset
; /* write position in the output file descriptor */
105 char path_name
[PATH_MAX
]; /* tracefile name */
106 enum lttng_consumer_stream_state state
;
110 enum lttng_event_output output
; /* splice or mmap */
114 struct lttng_ust_lib_ring_buffer
*buf
;
117 int hangup_flush_done
;
118 /* UID/GID of the user owning the session to which stream belongs */
124 * UST consumer local data to the program. One or more instance per
127 struct lttng_consumer_local_data
{
129 * Function to call when data is available on a buffer.
130 * Returns the number of bytes read, or negative error value.
132 ssize_t (*on_buffer_ready
)(struct lttng_consumer_stream
*stream
,
133 struct lttng_consumer_local_data
*ctx
);
135 * function to call when we receive a new channel, it receives a
136 * newly allocated channel, depending on the return code of this
137 * function, the new channel will be handled by the application
141 * > 0 (success, FD is kept by application)
142 * == 0 (success, FD is left to library)
145 int (*on_recv_channel
)(struct lttng_consumer_channel
*channel
);
147 * function to call when we receive a new stream, it receives a
148 * newly allocated stream, depending on the return code of this
149 * function, the new stream will be handled by the application
153 * > 0 (success, FD is kept by application)
154 * == 0 (success, FD is left to library)
157 int (*on_recv_stream
)(struct lttng_consumer_stream
*stream
);
159 * function to call when a stream is getting updated by the session
160 * daemon, this function receives the sessiond key and the new
161 * state, depending on the return code of this function the
162 * update of state for the stream is handled by the application
166 * > 0 (success, FD is kept by application)
167 * == 0 (success, FD is left to library)
170 int (*on_update_stream
)(int sessiond_key
, uint32_t state
);
171 /* socket to communicate errors with sessiond */
172 int consumer_error_socket
;
173 /* socket to exchange commands with sessiond */
174 char *consumer_command_sock_path
;
175 /* communication with splice */
176 int consumer_thread_pipe
[2];
177 /* pipe to wake the poll thread when necessary */
178 int consumer_poll_pipe
[2];
179 /* to let the signal handler wake up the fd receiver thread */
180 int consumer_should_quit
[2];
184 * Library-level data. One instance per process.
186 struct lttng_consumer_global_data
{
189 * At this time, this lock is used to ensure coherence between the count
190 * and number of element in the hash table. It's also a protection for
191 * concurrent read/write between threads.
193 * XXX: We need to see if this lock is still needed with the lockless RCU
196 pthread_mutex_t lock
;
199 * Number of streams in the hash table. Protected by consumer_data.lock.
203 * Hash tables of streams and channels. Protected by consumer_data.lock.
205 struct lttng_ht
*stream_ht
;
206 struct lttng_ht
*channel_ht
;
208 * Flag specifying if the local array of FDs needs update in the
209 * poll function. Protected by consumer_data.lock.
211 unsigned int need_update
;
212 enum lttng_consumer_type type
;
216 * Init consumer data structures.
218 extern void lttng_consumer_init(void);
221 * Set the error socket for communication with a session daemon.
223 extern void lttng_consumer_set_error_sock(
224 struct lttng_consumer_local_data
*ctx
, int sock
);
227 * Set the command socket path for communication with a session daemon.
229 extern void lttng_consumer_set_command_sock_path(
230 struct lttng_consumer_local_data
*ctx
, char *sock
);
233 * Send return code to session daemon.
235 * Returns the return code of sendmsg : the number of bytes transmitted or -1
238 extern int lttng_consumer_send_error(
239 struct lttng_consumer_local_data
*ctx
, int cmd
);
242 * Called from signal handler to ensure a clean exit.
244 extern void lttng_consumer_should_exit(
245 struct lttng_consumer_local_data
*ctx
);
248 * Cleanup the daemon's socket on exit.
250 extern void lttng_consumer_cleanup(void);
253 * Flush pending writes to trace output disk file.
255 extern void lttng_consumer_sync_trace_file(
256 struct lttng_consumer_stream
*stream
, off_t orig_offset
);
259 * Poll on the should_quit pipe and the command socket return -1 on error and
260 * should exit, 0 if data is available on the command socket
262 extern int lttng_consumer_poll_socket(struct pollfd
*kconsumer_sockpoll
);
264 extern int consumer_update_poll_array(
265 struct lttng_consumer_local_data
*ctx
, struct pollfd
**pollfd
,
266 struct lttng_consumer_stream
**local_consumer_streams
);
268 extern struct lttng_consumer_stream
*consumer_allocate_stream(
269 int channel_key
, int stream_key
,
270 int shm_fd
, int wait_fd
,
271 enum lttng_consumer_stream_state state
,
273 enum lttng_event_output output
,
274 const char *path_name
,
277 extern int consumer_add_stream(struct lttng_consumer_stream
*stream
);
278 extern void consumer_del_stream(struct lttng_consumer_stream
*stream
);
279 extern void consumer_change_stream_state(int stream_key
,
280 enum lttng_consumer_stream_state state
);
281 extern void consumer_del_channel(struct lttng_consumer_channel
*channel
);
282 extern struct lttng_consumer_channel
*consumer_allocate_channel(
284 int shm_fd
, int wait_fd
,
286 uint64_t max_sb_size
);
287 int consumer_add_channel(struct lttng_consumer_channel
*channel
);
289 extern struct lttng_consumer_local_data
*lttng_consumer_create(
290 enum lttng_consumer_type type
,
291 ssize_t (*buffer_ready
)(struct lttng_consumer_stream
*stream
,
292 struct lttng_consumer_local_data
*ctx
),
293 int (*recv_channel
)(struct lttng_consumer_channel
*channel
),
294 int (*recv_stream
)(struct lttng_consumer_stream
*stream
),
295 int (*update_stream
)(int sessiond_key
, uint32_t state
));
296 extern void lttng_consumer_destroy(struct lttng_consumer_local_data
*ctx
);
297 extern ssize_t
lttng_consumer_on_read_subbuffer_mmap(
298 struct lttng_consumer_local_data
*ctx
,
299 struct lttng_consumer_stream
*stream
, unsigned long len
);
300 extern ssize_t
lttng_consumer_on_read_subbuffer_splice(
301 struct lttng_consumer_local_data
*ctx
,
302 struct lttng_consumer_stream
*stream
, unsigned long len
);
303 extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data
*ctx
,
304 struct lttng_consumer_stream
*stream
);
305 extern int lttng_consumer_get_produced_snapshot(
306 struct lttng_consumer_local_data
*ctx
,
307 struct lttng_consumer_stream
*stream
,
309 extern void *lttng_consumer_thread_poll_fds(void *data
);
310 extern void *lttng_consumer_thread_receive_fds(void *data
);
311 extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data
*ctx
,
312 int sock
, struct pollfd
*consumer_sockpoll
);
314 ssize_t
lttng_consumer_read_subbuffer(struct lttng_consumer_stream
*stream
,
315 struct lttng_consumer_local_data
*ctx
);
316 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream
*stream
);
318 #endif /* _LTTNG_CONSUMER_H */