[lttng-tools.git] / include / lttng / lttng-consumer.h

/*
 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
 * Copyright (C) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; only version 2
 * of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef _LTTNG_CONSUMER_H
#define _LTTNG_CONSUMER_H

#include <limits.h>
#include <poll.h>
#include <urcu/list.h>
#include <lttng/lttng.h>

/*
 * When the receiving thread dies, we need to have a way to make the polling
 * thread exit eventually. If all FDs hang up (normal case when the
 * lttng-sessiond stops), we can exit cleanly, but if there is a problem and
 * for whatever reason some FDs remain open, the consumer should still exit
 * eventually.
 *
 * If the timeout is reached, it means that during this period no events
 * occurred on the FDs so we need to force an exit. This case should not happen
 * but it is a safety to ensure we won't block the consumer indefinitely.
 *
 * The value of 2 seconds is an arbitrary choice.
 */
#define LTTNG_CONSUMER_POLL_TIMEOUT 2000

/* Commands for consumer */
enum lttng_consumer_command {
	LTTNG_CONSUMER_ADD_CHANNEL,
	LTTNG_CONSUMER_ADD_STREAM,
	/* pause, delete, active depending on fd state */
	LTTNG_CONSUMER_UPDATE_STREAM,
	/* inform the consumer to quit when all fd has hang up */
	LTTNG_CONSUMER_STOP,
};

/* State of each fd in consumer */
enum lttng_consumer_stream_state {
	LTTNG_CONSUMER_ACTIVE_STREAM,
	LTTNG_CONSUMER_PAUSE_STREAM,
	LTTNG_CONSUMER_DELETE_STREAM,
};

struct lttng_consumer_channel_list {
	struct cds_list_head head;
};

struct lttng_consumer_stream_list {
	struct cds_list_head head;
};

enum lttng_consumer_type {
	LTTNG_CONSUMER_UNKNOWN = 0,
	LTTNG_CONSUMER_KERNEL,
	LTTNG_CONSUMER_UST,
};

struct lttng_consumer_channel {
	struct cds_list_head list;
	int key;
	uint64_t max_sb_size; /* the subbuffer size for this channel */
	int refcount; /* Number of streams referencing this channel */
	/* For UST */
	int shm_fd;
	int wait_fd;
	void *mmap_base;
	size_t mmap_len;
	struct lttng_ust_shm_handle *handle;
	int nr_streams;
	int shm_fd_is_copy;
	int wait_fd_is_copy;
};

/* Forward declaration for UST. */
struct lttng_ust_lib_ring_buffer;

/*
 * Internal representation of the streams, sessiond_key is used to identify
 * uniquely a stream.
 */
struct lttng_consumer_stream {
	struct cds_list_head list;
	struct lttng_consumer_channel *chan;	/* associated channel */
	/*
	 * key is the key used by the session daemon to refer to the
	 * object in the consumer daemon.
	 */
	int key;
	int shm_fd;
	int wait_fd;
	int out_fd; /* output file to write the data */
	off_t out_fd_offset; /* write position in the output file descriptor */
	char path_name[PATH_MAX]; /* tracefile name */
	enum lttng_consumer_stream_state state;
	size_t shm_len;
	void *mmap_base;
	size_t mmap_len;
	enum lttng_event_output output; /* splice or mmap */
	int shm_fd_is_copy;
	int wait_fd_is_copy;
	/* For UST */
	struct lttng_ust_lib_ring_buffer *buf;
	int cpu;
};

/*
 * UST consumer local data to the program. One or more instance per
 * process.
 */
struct lttng_consumer_local_data {
	/* function to call when data is available on a buffer */
	int (*on_buffer_ready)(struct lttng_consumer_stream *stream);
	/*
	 * function to call when we receive a new channel, it receives a
	 * newly allocated channel, depending on the return code of this
	 * function, the new channel will be handled by the application
	 * or the library.
	 *
	 * Returns:
	 *    > 0 (success, FD is kept by application)
	 *   == 0 (success, FD is left to library)
	 *    < 0 (error)
	 */
	int (*on_recv_channel)(struct lttng_consumer_channel *channel);
	/*
	 * function to call when we receive a new stream, it receives a
	 * newly allocated stream, depending on the return code of this
	 * function, the new stream will be handled by the application
	 * or the library.
	 *
	 * Returns:
	 *    > 0 (success, FD is kept by application)
	 *   == 0 (success, FD is left to library)
	 *    < 0 (error)
	 */
	int (*on_recv_stream)(struct lttng_consumer_stream *stream);
	/*
	 * function to call when a stream is getting updated by the session
	 * daemon, this function receives the sessiond key and the new
	 * state, depending on the return code of this function the
	 * update of state for the stream is handled by the application
	 * or the library.
	 *
	 * Returns:
	 *    > 0 (success, FD is kept by application)
	 *   == 0 (success, FD is left to library)
	 *    < 0 (error)
	 */
	int (*on_update_stream)(int sessiond_key, uint32_t state);
	/* socket to communicate errors with sessiond */
	int consumer_error_socket;
	/* socket to exchange commands with sessiond */
	char *consumer_command_sock_path;
	/* communication with splice */
	int consumer_thread_pipe[2];
	/* pipe to wake the poll thread when necessary */
	int consumer_poll_pipe[2];
	/* to let the signal handler wake up the fd receiver thread */
	int consumer_should_quit[2];
};

/*
 * Library-level data. One instance per process.
 */
struct lttng_consumer_global_data {
	/*
	 * consumer_data.lock protects consumer_data.fd_list,
	 * consumer_data.stream_count, and consumer_data.need_update. It
	 * ensures the count matches the number of items in the fd_list.
	 * It ensures the list updates *always* trigger an fd_array
	 * update (therefore need to make list update vs
	 * consumer_data.need_update flag update atomic, and also flag
	 * read, fd array and flag clear atomic).
	 */
	pthread_mutex_t lock;
	/*
	 * Number of streams in the list below. Protected by
	 * consumer_data.lock.
	 */
	int stream_count;
	/*
	 * Lists of streams and channels. Protected by consumer_data.lock.
	 */
	struct lttng_consumer_stream_list stream_list;
	struct lttng_consumer_channel_list channel_list;
	/*
	 * Flag specifying if the local array of FDs needs update in the
	 * poll function. Protected by consumer_data.lock.
	 */
	unsigned int need_update;
	enum lttng_consumer_type type;
};

/*
 * Set the error socket for communication with a session daemon.
 */
extern void lttng_consumer_set_error_sock(
		struct lttng_consumer_local_data *ctx, int sock);

/*
 * Set the command socket path for communication with a session daemon.
 */
extern void lttng_consumer_set_command_sock_path(
		struct lttng_consumer_local_data *ctx, char *sock);

/*
 * Send return code to session daemon.
 *
 * Returns the return code of sendmsg : the number of bytes transmitted or -1
 * on error.
 */
extern int lttng_consumer_send_error(
		struct lttng_consumer_local_data *ctx, int cmd);

/*
 * Called from signal handler to ensure a clean exit.
 */
extern void lttng_consumer_should_exit(
		struct lttng_consumer_local_data *ctx);

/*
 * Cleanup the daemon's socket on exit.
 */
extern void lttng_consumer_cleanup(void);

/*
 * Flush pending writes to trace output disk file.
 */
extern void lttng_consumer_sync_trace_file(
		struct lttng_consumer_stream *stream, off_t orig_offset);

/*
 * Poll on the should_quit pipe and the command socket return -1 on error and
 * should exit, 0 if data is available on the command socket
 */
extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);

extern int consumer_update_poll_array(
		struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
		struct lttng_consumer_stream **local_consumer_streams);

extern struct lttng_consumer_stream *consumer_allocate_stream(
		int channel_key, int stream_key,
		int shm_fd, int wait_fd,
		enum lttng_consumer_stream_state state,
		uint64_t mmap_len,
		enum lttng_event_output output,
		const char *path_name);
extern int consumer_add_stream(struct lttng_consumer_stream *stream);
extern void consumer_del_stream(struct lttng_consumer_stream *stream);
extern void consumer_change_stream_state(int stream_key,
		enum lttng_consumer_stream_state state);
extern void consumer_del_channel(struct lttng_consumer_channel *channel);
extern struct lttng_consumer_channel *consumer_allocate_channel(
		int channel_key,
		int shm_fd, int wait_fd,
		uint64_t mmap_len,
		uint64_t max_sb_size);
int consumer_add_channel(struct lttng_consumer_channel *channel);

extern struct lttng_consumer_local_data *lttng_consumer_create(
		enum lttng_consumer_type type,
		int (*buffer_ready)(struct lttng_consumer_stream *stream),
		int (*recv_channel)(struct lttng_consumer_channel *channel),
		int (*recv_stream)(struct lttng_consumer_stream *stream),
		int (*update_stream)(int sessiond_key, uint32_t state));
extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
extern int lttng_consumer_on_read_subbuffer_mmap(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream, unsigned long len);
extern int lttng_consumer_on_read_subbuffer_splice(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream, unsigned long len);
extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream);
extern int lttng_consumer_get_produced_snapshot(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream,
		unsigned long *pos);
extern void *lttng_consumer_thread_poll_fds(void *data);
extern void *lttng_consumer_thread_receive_fds(void *data);
extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
		int sock, struct pollfd *consumer_sockpoll);

#endif /* _LTTNG_CONSUMER_H */
Commit	Line	Data
3bd1e081 MD	1	/*
	2	* Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
	3	* Copyright (C) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	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
	8	* of the License.
	9	*
	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.
	14	*
	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.
	18	*/
	19
	20	#ifndef _LTTNG_CONSUMER_H
	21	#define _LTTNG_CONSUMER_H
	22
	23	#include <limits.h>
	24	#include <poll.h>
	25	#include <urcu/list.h>
	26	#include <lttng/lttng.h>
	27
	28	/*
	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
32258573 DG	31	* lttng-sessiond stops), we can exit cleanly, but if there is a problem and
32258573 DG	32	* for whatever reason some FDs remain open, the consumer should still exit
3bd1e081 MD	33	* eventually.
	34	*
	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.
	38	*
	39	* The value of 2 seconds is an arbitrary choice.
	40	*/
	41	#define LTTNG_CONSUMER_POLL_TIMEOUT 2000
	42
	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 */
	50	LTTNG_CONSUMER_STOP,
	51	};
	52
	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,
	58	};
	59
	60	struct lttng_consumer_channel_list {
	61	struct cds_list_head head;
	62	};
	63
	64	struct lttng_consumer_stream_list {
	65	struct cds_list_head head;
	66	};
	67
	68	enum lttng_consumer_type {
	69	LTTNG_CONSUMER_UNKNOWN = 0,
	70	LTTNG_CONSUMER_KERNEL,
	71	LTTNG_CONSUMER_UST,
	72	};
	73
	74	struct lttng_consumer_channel {
	75	struct cds_list_head list;
	76	int key;
	77	uint64_t max_sb_size; /* the subbuffer size for this channel */
	78	int refcount; /* Number of streams referencing this channel */
	79	/* For UST */
	80	int shm_fd;
	81	int wait_fd;
	82	void *mmap_base;
	83	size_t mmap_len;
13161846	84	struct lttng_ust_shm_handle *handle;
3bd1e081	85	int nr_streams;
b5c5fc29 MD	86	int shm_fd_is_copy;
b5c5fc29 MD	87	int wait_fd_is_copy;
3bd1e081 MD	88	};
	89
	90	/* Forward declaration for UST. */
13161846	91	struct lttng_ust_lib_ring_buffer;
3bd1e081 MD	92
	93	/*
	94	* Internal representation of the streams, sessiond_key is used to identify
	95	* uniquely a stream.
	96	*/
	97	struct lttng_consumer_stream {
	98	struct cds_list_head list;
	99	struct lttng_consumer_channel chan; / associated channel */
	100	/*
	101	* key is the key used by the session daemon to refer to the
	102	* object in the consumer daemon.
	103	*/
	104	int key;
	105	int shm_fd;
	106	int wait_fd;
	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;
	111	size_t shm_len;
	112	void *mmap_base;
	113	size_t mmap_len;
	114	enum lttng_event_output output; /* splice or mmap */
b5c5fc29 MD	115	int shm_fd_is_copy;
b5c5fc29 MD	116	int wait_fd_is_copy;
3bd1e081	117	/* For UST */
13161846	118	struct lttng_ust_lib_ring_buffer *buf;
3bd1e081 MD	119	int cpu;
	120	};
	121
	122	/*
	123	* UST consumer local data to the program. One or more instance per
	124	* process.
	125	*/
	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);
	129	/*
	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
	133	* or the library.
	134	*
	135	* Returns:
	136	* > 0 (success, FD is kept by application)
	137	* == 0 (success, FD is left to library)
	138	* < 0 (error)
	139	*/
	140	int (on_recv_channel)(struct lttng_consumer_channel channel);
	141	/*
	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
	145	* or the library.
	146	*
	147	* Returns:
	148	* > 0 (success, FD is kept by application)
	149	* == 0 (success, FD is left to library)
	150	* < 0 (error)
	151	*/
	152	int (on_recv_stream)(struct lttng_consumer_stream stream);
	153	/*
	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
	158	* or the library.
	159	*
	160	* Returns:
	161	* > 0 (success, FD is kept by application)
	162	* == 0 (success, FD is left to library)
	163	* < 0 (error)
	164	*/
	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];
	176	};
	177
	178	/*
	179	* Library-level data. One instance per process.
	180	*/
	181	struct lttng_consumer_global_data {
	182	/*
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).
190	*/
191	pthread_mutex_t lock;
192	/*
193	* Number of streams in the list below. Protected by
194	* consumer_data.lock.
195	*/
196	int stream_count;
197	/*
198	* Lists of streams and channels. Protected by consumer_data.lock.
199	*/
200	struct lttng_consumer_stream_list stream_list;
201	struct lttng_consumer_channel_list channel_list;
202	/*
203	* Flag specifying if the local array of FDs needs update in the
204	* poll function. Protected by consumer_data.lock.
205	*/
206	unsigned int need_update;
207	enum lttng_consumer_type type;
208	};
209
210	/*
211	* Set the error socket for communication with a session daemon.
212	*/
213	extern void lttng_consumer_set_error_sock(
214	struct lttng_consumer_local_data *ctx, int sock);
215
216	/*
217	* Set the command socket path for communication with a session daemon.
218	*/
219	extern void lttng_consumer_set_command_sock_path(
220	struct lttng_consumer_local_data ctx, char sock);
221
222	/*
223	* Send return code to session daemon.
224	*
225	* Returns the return code of sendmsg : the number of bytes transmitted or -1
226	* on error.
227	*/
228	extern int lttng_consumer_send_error(
229	struct lttng_consumer_local_data *ctx, int cmd);
230
231	/*
232	* Called from signal handler to ensure a clean exit.
233	*/
234	extern void lttng_consumer_should_exit(
235	struct lttng_consumer_local_data *ctx);
236
237	/*
238	* Cleanup the daemon's socket on exit.
239	*/
240	extern void lttng_consumer_cleanup(void);
241
242	/*
243	* Flush pending writes to trace output disk file.
244	*/
245	extern void lttng_consumer_sync_trace_file(
246	struct lttng_consumer_stream *stream, off_t orig_offset);
247
248	/*
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
251	*/
252	extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
253
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);
257
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,
262	uint64_t mmap_len,
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(
271	int channel_key,
272	int shm_fd, int wait_fd,
273	uint64_t mmap_len,
274	uint64_t max_sb_size);
275	int consumer_add_channel(struct lttng_consumer_channel *channel);
276
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,
295	unsigned long *pos);
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);
300
301	#endif /* _LTTNG_CONSUMER_H */