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8ba26eae MD |
1 | /* |
2 | * liblttd header file | |
008e2515 | 3 | * |
8ba26eae | 4 | * Copyright 2005-2010 - |
d9cbca27 | 5 | * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
008e2515 MSL |
6 | * Copyright 2010- |
7 | * Oumarou Dicko <oumarou.dicko@polymtl.ca> | |
8 | * Michael Sills-Lavoie <michael.sills-lavoie@polymtl.ca> | |
9 | * | |
8ba26eae MD |
10 | * This library is free software; you can redistribute it and/or |
11 | * modify it under the terms of the GNU Lesser General Public | |
12 | * License as published by the Free Software Foundation; either | |
13 | * version 2.1 of the License, or (at your option) any later version. | |
008e2515 | 14 | * |
8ba26eae | 15 | * This library is distributed in the hope that it will be useful, |
008e2515 | 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
8ba26eae MD |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
18 | * Lesser General Public License for more details. | |
008e2515 | 19 | * |
8ba26eae MD |
20 | * You should have received a copy of the GNU Lesser General Public |
21 | * License along with this library; if not, write to the Free Software | |
22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
008e2515 MSL |
23 | */ |
24 | ||
25 | #ifndef _LIBLTTD_H | |
26 | #define _LIBLTTD_H | |
27 | ||
28 | #include <pthread.h> | |
d9cbca27 | 29 | #include <dirent.h> |
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30 | |
31 | /** | |
d6d516b7 MSL |
32 | * struct fd_pair - Contains the data associated with the channel file |
33 | * descriptor. The lib user can use user_data to store the data associated to | |
34 | * the specified channel. The lib user can read but MUST NOT change the other | |
35 | * attributes. | |
36 | * @channel: channel file descriptor | |
37 | * @n_sb: the number of subbuffer for this channel | |
38 | * @max_sb_size: the subbuffer size for this channel | |
39 | * @mmap: Not used anymore. | |
40 | * @mutex: a mutex for internal library usage | |
41 | * @user_data: library user data | |
42 | */ | |
008e2515 | 43 | struct fd_pair { |
008e2515 | 44 | int channel; |
008e2515 | 45 | unsigned int n_sb; |
008e2515 | 46 | unsigned int max_sb_size; |
008e2515 | 47 | void *mmap; |
008e2515 | 48 | pthread_mutex_t mutex; |
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49 | void *user_data; |
50 | }; | |
51 | ||
d9cbca27 MSL |
52 | struct channel_trace_fd { |
53 | struct fd_pair *pair; | |
54 | int num_pairs; | |
55 | }; | |
56 | ||
57 | struct inotify_watch { | |
58 | int wd; | |
59 | char path_channel[PATH_MAX]; | |
60 | char *base_path_channel; | |
61 | }; | |
62 | ||
63 | struct inotify_watch_array { | |
64 | struct inotify_watch *elem; | |
65 | int num; | |
66 | }; | |
67 | ||
68 | struct liblttd_callbacks; | |
69 | ||
70 | /** | |
71 | * struct liblttd_instance - Contains the data associated with a trace instance. | |
72 | * The lib user can read but MUST NOT change any attributes but callbacks. | |
73 | * @callbacks: Contains the necessary callbacks for a tracing session. | |
74 | */ | |
75 | struct liblttd_instance { | |
76 | struct liblttd_callbacks *callbacks; | |
77 | ||
78 | int inotify_fd; | |
79 | struct channel_trace_fd fd_pairs; | |
80 | struct inotify_watch_array inotify_watch_array; | |
81 | ||
82 | /* protects fd_pairs and inotify_watch_array */ | |
83 | pthread_rwlock_t fd_pairs_lock; | |
84 | ||
85 | char channel_name[PATH_MAX]; | |
86 | unsigned long num_threads; | |
87 | int quit_program; | |
88 | int dump_flight_only; | |
89 | int dump_normal_only; | |
90 | int verbose_mode; | |
91 | }; | |
d6d516b7 | 92 | |
008e2515 | 93 | /** |
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94 | * struct liblttd_callbacks - Contains the necessary callbacks for a tracing |
95 | * session. The user can set the unnecessary functions to NULL if he does not | |
96 | * need them. | |
008e2515 MSL |
97 | */ |
98 | struct liblttd_callbacks { | |
99 | /** | |
d6d516b7 | 100 | * on_open_channel - Is called after a channel file is open. |
8ba26eae MD |
101 | * |
102 | * @data: pointer to the callbacks structure that has been passed to | |
103 | * the lib. | |
d6d516b7 | 104 | * @pair: structure that contains the data associated with the |
8ba26eae MD |
105 | * channel file descriptor. The library user can use user_data to |
106 | * store the data associated to the specified channel. | |
107 | * @relative_channel_path: | |
108 | * represents a relative path to the channel file. This path is | |
109 | * relative to the root folder of the trace channels. | |
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110 | * |
111 | * Returns 0 if the callback succeeds else not 0. | |
112 | */ | |
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113 | int (*on_open_channel)(struct liblttd_callbacks *data, |
114 | struct fd_pair *pair, | |
115 | char *relative_channel_path); | |
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116 | |
117 | /** | |
d6d516b7 | 118 | * on_close_channel - Is called after a channel file is closed. |
8ba26eae MD |
119 | * |
120 | * @data: pointer to the callbacks structure that has been passed to the | |
121 | * lib. | |
d6d516b7 | 122 | * @pair: structure that contains the data associated with the channel |
8ba26eae MD |
123 | * file descriptor. The lib user should clean user_data at this |
124 | * time. | |
d6d516b7 MSL |
125 | * |
126 | * Returns 0 if the callback succeeds else not 0. | |
127 | * | |
128 | * After a channel file has been closed, it will never be read again. | |
129 | */ | |
8ba26eae MD |
130 | int (*on_close_channel)(struct liblttd_callbacks *data, |
131 | struct fd_pair *pair); | |
008e2515 | 132 | |
008e2515 | 133 | /** |
d6d516b7 MSL |
134 | * on_new_channels_folder - Is called when the library enter in a new |
135 | * subfolder while it is scanning the trace channel tree. It can be used | |
136 | * to create the output file structure of the trace. | |
8ba26eae MD |
137 | * |
138 | * @data: pointer to the callbacks structure that has been passed to the | |
139 | * library. | |
140 | * @relative_folder_path: | |
141 | * represents a relative path to the channel folder. This path is | |
142 | * relative to the root folder of the trace channels. | |
d6d516b7 MSL |
143 | * |
144 | * Returns 0 if the callback succeeds else not 0. | |
145 | */ | |
8ba26eae MD |
146 | int (*on_new_channels_folder)(struct liblttd_callbacks *data, |
147 | char *relative_folder_path); | |
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148 | |
149 | /** | |
d6d516b7 MSL |
150 | * on_read_subbuffer - Is called after a subbuffer is a reserved. |
151 | * | |
8ba26eae MD |
152 | * @data: pointer to the callbacks structure that has been passed to the |
153 | * library. | |
154 | * @pair: structure that contains the data associated with the channel | |
155 | * file descriptor. | |
156 | * @len: represents the length the data that has to be read. | |
d6d516b7 MSL |
157 | * |
158 | * Returns 0 if the callback succeeds else not 0. | |
159 | * | |
8ba26eae | 160 | * It has to be thread safe, because it is called by many threads. |
d6d516b7 | 161 | */ |
8ba26eae MD |
162 | int (*on_read_subbuffer)(struct liblttd_callbacks *data, |
163 | struct fd_pair *pair, unsigned int len); | |
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164 | |
165 | /** | |
d6d516b7 MSL |
166 | * on_trace_en - Is called at the very end of the tracing session. At |
167 | * this time, all the channels have been closed and the threads have | |
168 | * been destroyed. | |
169 | * | |
8ba26eae MD |
170 | * @instance: pointer to the instance structure that has been passed to |
171 | * the library. | |
d6d516b7 MSL |
172 | * |
173 | * Returns 0 if the callback succeeds else not 0. | |
174 | * | |
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175 | * After this callback is called, no other callback will be called |
176 | * again and the tracing instance will be deleted automatically by | |
177 | * liblttd. After this call, the user must not use the liblttd instance. | |
178 | */ | |
8ba26eae | 179 | int (*on_trace_end)(struct liblttd_instance *instance); |
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180 | |
181 | /** | |
d6d516b7 MSL |
182 | * on_new_thread - Is called after a new thread has been created. |
183 | * | |
8ba26eae MD |
184 | * @data: pointer to the callbacks structure that has been passed to the |
185 | * lib. | |
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186 | * @thread_num: represents the id of the thread. |
187 | * | |
188 | * Returns 0 if the callback succeeds else not 0. | |
189 | * | |
8ba26eae | 190 | * It has to be thread safe, because it is called by many threads. |
d6d516b7 | 191 | */ |
8ba26eae MD |
192 | int (*on_new_thread)(struct liblttd_callbacks *data, |
193 | unsigned long thread_num); | |
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194 | |
195 | /** | |
8ba26eae | 196 | * on_close_thread - Is called just before a thread is destroyed. |
d6d516b7 | 197 | * |
8ba26eae MD |
198 | * @data: pointer to the callbacks structure that has been passed to the |
199 | * library. | |
d6d516b7 MSL |
200 | * @thread_num: represents the number of the thread. |
201 | * | |
202 | * Returns 0 if the callback succeeds else not 0. | |
203 | * | |
8ba26eae | 204 | * It has to be thread safe, because it is called by many threads. |
d6d516b7 | 205 | */ |
8ba26eae MD |
206 | int (*on_close_thread)(struct liblttd_callbacks *data, |
207 | unsigned long thread_num); | |
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208 | |
209 | /** | |
d6d516b7 MSL |
210 | * The library's data. |
211 | */ | |
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212 | void *user_data; |
213 | }; | |
214 | ||
215 | /** | |
d6d516b7 MSL |
216 | * liblttd_new_instance - Is called to create a new tracing session. |
217 | * | |
8ba26eae MD |
218 | * @callbacks: Pointer to a callbacks structure that contain the user |
219 | * callbacks and data. | |
d6d516b7 | 220 | * @channel_path: This argument is a path to the root folder of the trace's |
8ba26eae MD |
221 | * channels. |
222 | * @n_threads: This argument represents the number of threads that will be | |
223 | * used by the library. | |
224 | * @flight_only: If this argument to set to 1, only the channel that are in | |
225 | * flight recorder mode will be recorded. | |
226 | * @normal_only: If this argument to set to 1, only the channel that are in | |
227 | * normal mode will be recorded. | |
228 | * @verbose: If this argument to set to 1, more informations will be | |
229 | * printed. | |
d6d516b7 MSL |
230 | * |
231 | * Returns the instance if the function succeeds else NULL. | |
232 | */ | |
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233 | struct liblttd_instance * |
234 | liblttd_new_instance(struct liblttd_callbacks *callbacks, char *channel_path, | |
235 | unsigned long n_threads, int flight_only, int normal_only, | |
236 | int verbose); | |
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237 | |
238 | /** | |
d6d516b7 MSL |
239 | * liblttd_start - Is called to start a new tracing session. |
240 | * | |
8ba26eae | 241 | * @instance: The tracing session instance that needs to be started. |
d6d516b7 MSL |
242 | * |
243 | * Returns 0 if the function succeeds. | |
244 | * | |
8ba26eae MD |
245 | * This is a blocking function. The caller will be blocked on it until the |
246 | * tracing session is stopped by the user using liblttd_stop_instance or until | |
247 | * the trace is stopped by LTTng directly. | |
d6d516b7 MSL |
248 | */ |
249 | int liblttd_start_instance(struct liblttd_instance *instance); | |
250 | ||
251 | /** | |
252 | * liblttd_stop - Is called to stop a tracing session. | |
253 | * | |
254 | * @instance: The tracing session instance that needs to be stoped. | |
255 | * | |
256 | * Returns 0 if the function succeeds. | |
257 | * | |
8ba26eae MD |
258 | * This function returns immediately, it only tells liblttd to stop the |
259 | * instance. The on_trace_end callback will be called when the tracing session | |
260 | * will really be stopped (after every thread has finished using it). The | |
261 | * instance is deleted automatically by liblttd after on_trace_end is called. | |
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262 | */ |
263 | int liblttd_stop_instance(struct liblttd_instance *instance); | |
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264 | |
265 | #endif /*_LIBLTTD_H */ |