ust consumer: flag shm/wait fd as copy
[lttng-tools.git] / include / lttng / lttng-consumer.h
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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
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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
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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 */
44enum 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 */
54enum lttng_consumer_stream_state {
55 LTTNG_CONSUMER_ACTIVE_STREAM,
56 LTTNG_CONSUMER_PAUSE_STREAM,
57 LTTNG_CONSUMER_DELETE_STREAM,
58};
59
60struct lttng_consumer_channel_list {
61 struct cds_list_head head;
62};
63
64struct lttng_consumer_stream_list {
65 struct cds_list_head head;
66};
67
68enum lttng_consumer_type {
69 LTTNG_CONSUMER_UNKNOWN = 0,
70 LTTNG_CONSUMER_KERNEL,
71 LTTNG_CONSUMER_UST,
72};
73
74struct 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;
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86 int shm_fd_is_copy;
87 int wait_fd_is_copy;
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88};
89
90/* Forward declaration for UST. */
13161846 91struct lttng_ust_lib_ring_buffer;
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92
93/*
94 * Internal representation of the streams, sessiond_key is used to identify
95 * uniquely a stream.
96 */
97struct 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 */
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115 int shm_fd_is_copy;
116 int wait_fd_is_copy;
3bd1e081 117 /* For UST */
13161846 118 struct lttng_ust_lib_ring_buffer *buf;
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119 int cpu;
120};
121
122/*
123 * UST consumer local data to the program. One or more instance per
124 * process.
125 */
126struct 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 */
181struct 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 */
213extern 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 */
219extern 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 */
228extern 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 */
234extern void lttng_consumer_should_exit(
235 struct lttng_consumer_local_data *ctx);
236
237/*
238 * Cleanup the daemon's socket on exit.
239 */
240extern void lttng_consumer_cleanup(void);
241
242/*
243 * Flush pending writes to trace output disk file.
244 */
245extern 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 */
252extern int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
253
254extern int consumer_update_poll_array(
255 struct lttng_consumer_local_data *ctx, struct pollfd **pollfd,
256 struct lttng_consumer_stream **local_consumer_streams);
257
258extern 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);
265extern int consumer_add_stream(struct lttng_consumer_stream *stream);
266extern void consumer_del_stream(struct lttng_consumer_stream *stream);
267extern void consumer_change_stream_state(int stream_key,
268 enum lttng_consumer_stream_state state);
269extern void consumer_del_channel(struct lttng_consumer_channel *channel);
270extern 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);
275int consumer_add_channel(struct lttng_consumer_channel *channel);
276
277extern 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));
283extern void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
284extern int lttng_consumer_on_read_subbuffer_mmap(
285 struct lttng_consumer_local_data *ctx,
286 struct lttng_consumer_stream *stream, unsigned long len);
287extern int lttng_consumer_on_read_subbuffer_splice(
288 struct lttng_consumer_local_data *ctx,
289 struct lttng_consumer_stream *stream, unsigned long len);
290extern int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx,
291 struct lttng_consumer_stream *stream);
292extern int lttng_consumer_get_produced_snapshot(
293 struct lttng_consumer_local_data *ctx,
294 struct lttng_consumer_stream *stream,
295 unsigned long *pos);
296extern void *lttng_consumer_thread_poll_fds(void *data);
297extern void *lttng_consumer_thread_receive_fds(void *data);
298extern int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
299 int sock, struct pollfd *consumer_sockpoll);
300
301#endif /* _LTTNG_CONSUMER_H */
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