[lttng-tools.git] / src / common / 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 <unistd.h>

#include <lttng/lttng.h>

#include "src/common/hashtable/hashtable.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,
};

enum lttng_consumer_type {
	LTTNG_CONSUMER_UNKNOWN = 0,
	LTTNG_CONSUMER_KERNEL,
	LTTNG_CONSUMER64_UST,
	LTTNG_CONSUMER32_UST,
};

struct lttng_consumer_channel {
	struct lttng_ht_node_ulong node;
	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 wait_fd_is_copy;
	int cpucount;
};

/* 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 lttng_ht_node_ulong node;
	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;
	int hangup_flush_done;
	/* UID/GID of the user owning the session to which stream belongs */
	uid_t uid;
	gid_t gid;
};

/*
 * 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,
			struct lttng_consumer_local_data *ctx);
	/*
	 * 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 {

	/*
	 * At this time, this lock is used to ensure coherence between the count
	 * and number of element in the hash table. It's also a protection for
	 * concurrent read/write between threads.
	 *
	 * XXX: We need to see if this lock is still needed with the lockless RCU
	 * hash tables.
	 */
	pthread_mutex_t lock;

	/*
	 * Number of streams in the hash table. Protected by consumer_data.lock.
	 */
	int stream_count;
	/*
	 * Hash tables of streams and channels. Protected by consumer_data.lock.
	 */
	struct lttng_ht *stream_ht;
	struct lttng_ht *channel_ht;
	/*
	 * 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;
};

/*
 * Init consumer data structures.
 */
extern void lttng_consumer_init(void);

/*
 * 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,
		uid_t uid,
		gid_t gid);
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,
			struct lttng_consumer_local_data *ctx),
		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);

int lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
		struct lttng_consumer_local_data *ctx);
int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);

#endif /* _LTTNG_CONSUMER_H */
Commit	Line	Data
	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 <unistd.h>
	26
	27	#include <lttng/lttng.h>
	28
	29	#include "src/common/hashtable/hashtable.h"
	30
	31	/*
	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
	36	* eventually.
	37	*
	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.
	41	*
	42	* The value of 2 seconds is an arbitrary choice.
	43	*/
	44	#define LTTNG_CONSUMER_POLL_TIMEOUT 2000
	45
	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 */
	53	LTTNG_CONSUMER_STOP,
	54	};
	55
	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,
	61	};
	62
	63	enum lttng_consumer_type {
	64	LTTNG_CONSUMER_UNKNOWN = 0,
	65	LTTNG_CONSUMER_KERNEL,
	66	LTTNG_CONSUMER64_UST,
	67	LTTNG_CONSUMER32_UST,
	68	};
	69
	70	struct lttng_consumer_channel {
	71	struct lttng_ht_node_ulong node;
	72	int key;
	73	uint64_t max_sb_size; /* the subbuffer size for this channel */
	74	int refcount; /* Number of streams referencing this channel */
	75	/* For UST */
	76	int shm_fd;
	77	int wait_fd;
	78	void *mmap_base;
	79	size_t mmap_len;
	80	struct lttng_ust_shm_handle *handle;
	81	int nr_streams;
	82	int wait_fd_is_copy;
	83	int cpucount;
	84	};
	85
	86	/* Forward declaration for UST. */
	87	struct lttng_ust_lib_ring_buffer;
	88
	89	/*
	90	* Internal representation of the streams, sessiond_key is used to identify
	91	* uniquely a stream.
	92	*/
	93	struct lttng_consumer_stream {
	94	struct lttng_ht_node_ulong node;
	95	struct lttng_consumer_channel chan; / associated channel */
	96	/*
	97	* key is the key used by the session daemon to refer to the
	98	* object in the consumer daemon.
	99	*/
	100	int key;
	101	int shm_fd;
	102	int wait_fd;
	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;
	107	size_t shm_len;
	108	void *mmap_base;
	109	size_t mmap_len;
	110	enum lttng_event_output output; /* splice or mmap */
	111	int shm_fd_is_copy;
	112	int wait_fd_is_copy;
	113	/* For UST */
	114	struct lttng_ust_lib_ring_buffer *buf;
	115	int cpu;
	116	int hangup_flush_done;
	117	/* UID/GID of the user owning the session to which stream belongs */
	118	uid_t uid;
	119	gid_t gid;
	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	struct lttng_consumer_local_data *ctx);
	130	/*
	131	* function to call when we receive a new channel, it receives a
	132	* newly allocated channel, depending on the return code of this
	133	* function, the new channel will be handled by the application
	134	* or the library.
	135	*
	136	* Returns:
	137	* > 0 (success, FD is kept by application)
	138	* == 0 (success, FD is left to library)
	139	* < 0 (error)
	140	*/
	141	int (on_recv_channel)(struct lttng_consumer_channel channel);
	142	/*
	143	* function to call when we receive a new stream, it receives a
	144	* newly allocated stream, depending on the return code of this
	145	* function, the new stream will be handled by the application
	146	* or the library.
	147	*
	148	* Returns:
	149	* > 0 (success, FD is kept by application)
	150	* == 0 (success, FD is left to library)
	151	* < 0 (error)
	152	*/
	153	int (on_recv_stream)(struct lttng_consumer_stream stream);
	154	/*
	155	* function to call when a stream is getting updated by the session
	156	* daemon, this function receives the sessiond key and the new
	157	* state, depending on the return code of this function the
	158	* update of state for the stream is handled by the application
	159	* or the library.
	160	*
	161	* Returns:
	162	* > 0 (success, FD is kept by application)
	163	* == 0 (success, FD is left to library)
	164	* < 0 (error)
	165	*/
	166	int (*on_update_stream)(int sessiond_key, uint32_t state);
	167	/* socket to communicate errors with sessiond */
	168	int consumer_error_socket;
	169	/* socket to exchange commands with sessiond */
	170	char *consumer_command_sock_path;
	171	/* communication with splice */
	172	int consumer_thread_pipe[2];
	173	/* pipe to wake the poll thread when necessary */
	174	int consumer_poll_pipe[2];
	175	/* to let the signal handler wake up the fd receiver thread */
	176	int consumer_should_quit[2];
	177	};
	178
	179	/*
	180	* Library-level data. One instance per process.
	181	*/
	182	struct lttng_consumer_global_data {
	183
	184	/*
	185	* At this time, this lock is used to ensure coherence between the count
	186	* and number of element in the hash table. It's also a protection for
	187	* concurrent read/write between threads.
	188	*
	189	* XXX: We need to see if this lock is still needed with the lockless RCU
	190	* hash tables.
	191	*/
	192	pthread_mutex_t lock;
	193
	194	/*
	195	* Number of streams in the hash table. Protected by consumer_data.lock.
	196	*/
	197	int stream_count;
	198	/*
	199	* Hash tables of streams and channels. Protected by consumer_data.lock.
	200	*/
	201	struct lttng_ht *stream_ht;
	202	struct lttng_ht *channel_ht;
	203	/*
	204	* Flag specifying if the local array of FDs needs update in the
	205	* poll function. Protected by consumer_data.lock.
	206	*/
	207	unsigned int need_update;
	208	enum lttng_consumer_type type;
	209	};
	210
	211	/*
	212	* Init consumer data structures.
	213	*/
	214	extern void lttng_consumer_init(void);
	215
	216	/*
	217	* Set the error socket for communication with a session daemon.
	218	*/
	219	extern void lttng_consumer_set_error_sock(
	220	struct lttng_consumer_local_data *ctx, int sock);
	221
	222	/*
	223	* Set the command socket path for communication with a session daemon.
	224	*/
	225	extern void lttng_consumer_set_command_sock_path(
	226	struct lttng_consumer_local_data ctx, char sock);
	227
	228	/*
	229	* Send return code to session daemon.
	230	*
	231	* Returns the return code of sendmsg : the number of bytes transmitted or -1
	232	* on error.
	233	*/
	234	extern int lttng_consumer_send_error(
	235	struct lttng_consumer_local_data *ctx, int cmd);
	236
	237	/*
	238	* Called from signal handler to ensure a clean exit.
	239	*/
	240	extern void lttng_consumer_should_exit(
	241	struct lttng_consumer_local_data *ctx);
	242
	243	/*
	244	* Cleanup the daemon's socket on exit.
	245	*/
	246	extern void lttng_consumer_cleanup(void);
	247
	248	/*
	249	* Flush pending writes to trace output disk file.
	250	*/
	251	extern void lttng_consumer_sync_trace_file(
	252	struct lttng_consumer_stream *stream, off_t orig_offset);
	253
	254	/*
	255	* Poll on the should_quit pipe and the command socket return -1 on error and
	256	* should exit, 0 if data is available on the command socket
	257	*/
	258	extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
	259
	260	extern int consumer_update_poll_array(
	261	struct lttng_consumer_local_data ctx, struct pollfd *pollfd,
	262	struct lttng_consumer_stream **local_consumer_streams);
	263
	264	extern struct lttng_consumer_stream *consumer_allocate_stream(
	265	int channel_key, int stream_key,
	266	int shm_fd, int wait_fd,
	267	enum lttng_consumer_stream_state state,
	268	uint64_t mmap_len,
	269	enum lttng_event_output output,
	270	const char *path_name,
	271	uid_t uid,
	272	gid_t gid);
	273	extern int consumer_add_stream(struct lttng_consumer_stream *stream);
	274	extern void consumer_del_stream(struct lttng_consumer_stream *stream);
	275	extern void consumer_change_stream_state(int stream_key,
	276	enum lttng_consumer_stream_state state);
	277	extern void consumer_del_channel(struct lttng_consumer_channel *channel);
	278	extern struct lttng_consumer_channel *consumer_allocate_channel(
	279	int channel_key,
	280	int shm_fd, int wait_fd,
	281	uint64_t mmap_len,
	282	uint64_t max_sb_size);
	283	int consumer_add_channel(struct lttng_consumer_channel *channel);
	284
	285	extern struct lttng_consumer_local_data *lttng_consumer_create(
	286	enum lttng_consumer_type type,
	287	int (buffer_ready)(struct lttng_consumer_stream stream,
	288	struct lttng_consumer_local_data *ctx),
	289	int (recv_channel)(struct lttng_consumer_channel channel),
	290	int (recv_stream)(struct lttng_consumer_stream stream),
	291	int (*update_stream)(int sessiond_key, uint32_t state));
	292	extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
	293	extern int lttng_consumer_on_read_subbuffer_mmap(
	294	struct lttng_consumer_local_data *ctx,
	295	struct lttng_consumer_stream *stream, unsigned long len);
	296	extern int lttng_consumer_on_read_subbuffer_splice(
	297	struct lttng_consumer_local_data *ctx,
	298	struct lttng_consumer_stream *stream, unsigned long len);
	299	extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
	300	struct lttng_consumer_stream *stream);
	301	extern int lttng_consumer_get_produced_snapshot(
	302	struct lttng_consumer_local_data *ctx,
	303	struct lttng_consumer_stream *stream,
	304	unsigned long *pos);
	305	extern void lttng_consumer_thread_poll_fds(void data);
	306	extern void lttng_consumer_thread_receive_fds(void data);
	307	extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
	308	int sock, struct pollfd *consumer_sockpoll);
	309
	310	int lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
	311	struct lttng_consumer_local_data *ctx);
	312	int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
	313
	314	#endif /* _LTTNG_CONSUMER_H */