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6533b585 DG |
1 | /* |
2 | * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; only version 2 | |
7 | * of the License. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | */ | |
18 | ||
19 | #ifndef _LTTNG_KCONSUMERD_H | |
20 | #define _LTTNG_KCONSUMERD_H | |
21 | ||
22 | #include <limits.h> | |
23 | #include <lttng/lttng.h> | |
24 | ||
25 | /* | |
26 | * When the receiving thread dies, we need to have a way to make the polling | |
27 | * thread exit eventually. If all FDs hang up (normal case when the | |
28 | * ltt-sessiond stops), we can exit cleanly, but if there is a problem and for | |
29 | * whatever reason some FDs remain open, the consumer should still exit | |
30 | * eventually. | |
31 | * | |
32 | * If the timeout is reached, it means that during this period no events | |
33 | * occurred on the FDs so we need to force an exit. This case should not happen | |
34 | * but it is a safety to ensure we won't block the consumer indefinitely. | |
35 | * | |
36 | * The value of 2 seconds is an arbitrary choice. | |
37 | */ | |
38 | #define LTTNG_KCONSUMERD_POLL_GRACE_PERIOD 2000 | |
39 | ||
40 | /* Commands for kconsumerd */ | |
41 | enum lttng_kconsumerd_command { | |
42 | ADD_STREAM, | |
43 | UPDATE_STREAM, /* pause, delete, active depending on fd state */ | |
44 | STOP, /* inform the kconsumerd to quit when all fd has hang up */ | |
45 | }; | |
46 | ||
47 | /* State of each fd in consumerd */ | |
48 | enum lttng_kconsumerd_fd_state { | |
49 | ACTIVE_FD, | |
50 | PAUSE_FD, | |
51 | DELETE_FD, | |
52 | }; | |
53 | ||
54 | struct lttng_kconsumerd_fd_list { | |
55 | struct cds_list_head head; | |
56 | }; | |
57 | ||
58 | /* | |
59 | * Internal representation of the FDs, sessiond_fd is used to identify uniquely | |
60 | * a fd | |
61 | */ | |
62 | struct lttng_kconsumerd_fd { | |
63 | struct cds_list_head list; | |
64 | int sessiond_fd; /* used to identify uniquely a fd with sessiond */ | |
65 | int consumerd_fd; /* fd to consume */ | |
66 | int out_fd; /* output file to write the data */ | |
67 | off_t out_fd_offset; /* write position in the output file descriptor */ | |
68 | char path_name[PATH_MAX]; /* tracefile name */ | |
69 | enum lttng_kconsumerd_fd_state state; | |
70 | unsigned long max_sb_size; /* the subbuffer size for this channel */ | |
71 | void *mmap_base; | |
72 | size_t mmap_len; | |
73 | enum lttng_event_output output; /* splice or mmap */ | |
74 | }; | |
75 | ||
76 | /* | |
77 | * Kernel consumer local data to the program. | |
78 | */ | |
79 | struct lttng_kconsumerd_local_data { | |
80 | /* function to call when data is available on a buffer */ | |
81 | int (*on_buffer_ready)(struct lttng_kconsumerd_fd *kconsumerd_fd); | |
82 | /* socket to communicate errors with sessiond */ | |
83 | int kconsumerd_error_socket; | |
84 | /* socket to exchange commands with sessiond */ | |
85 | char *kconsumerd_command_sock_path; | |
86 | /* communication with splice */ | |
87 | int kconsumerd_thread_pipe[2]; | |
88 | /* pipe to wake the poll thread when necessary */ | |
89 | int kconsumerd_poll_pipe[2]; | |
90 | /* to let the signal handler wake up the fd receiver thread */ | |
91 | int kconsumerd_should_quit[2]; | |
92 | }; | |
93 | ||
94 | /* | |
95 | * Initialise the necessary environnement: | |
96 | * - create a new context | |
97 | * - create the poll_pipe | |
98 | * - create the should_quit pipe (for signal handler) | |
99 | * - create the thread pipe (for splice) | |
100 | * | |
101 | * Takes a function pointer as argument, this function is called when data is | |
102 | * available on a buffer. This function is responsible to do the | |
103 | * kernctl_get_next_subbuf, read the data with mmap or splice depending on the | |
104 | * buffer configuration and then kernctl_put_next_subbuf at the end. | |
105 | * | |
106 | * Returns a pointer to the new context or NULL on error. | |
107 | */ | |
108 | extern struct lttng_kconsumerd_local_data *lttng_kconsumerd_create( | |
109 | int (*buffer_ready)(struct lttng_kconsumerd_fd *kconsumerd_fd)); | |
110 | ||
111 | /* | |
112 | * Close all fds associated with the instance and free the context. | |
113 | */ | |
114 | extern void lttng_kconsumerd_destroy(struct lttng_kconsumerd_local_data *ctx); | |
115 | ||
116 | /* | |
117 | * Mmap the ring buffer, read it and write the data to the tracefile. | |
118 | * | |
119 | * Returns the number of bytes written. | |
120 | */ | |
121 | extern int lttng_kconsumerd_on_read_subbuffer_mmap( | |
122 | struct lttng_kconsumerd_local_data *ctx, | |
123 | struct lttng_kconsumerd_fd *kconsumerd_fd, unsigned long len); | |
124 | ||
125 | /* | |
126 | * Splice the data from the ring buffer to the tracefile. | |
127 | * | |
128 | * Returns the number of bytes spliced. | |
129 | */ | |
130 | extern int lttng_kconsumerd_on_read_subbuffer_splice( | |
131 | struct lttng_kconsumerd_local_data *ctx, | |
132 | struct lttng_kconsumerd_fd *kconsumerd_fd, unsigned long len); | |
133 | ||
92ab9ab6 JD |
134 | /* |
135 | * Take a snapshot for a specific fd | |
136 | * | |
137 | * Returns 0 on success, < 0 on error | |
138 | */ | |
139 | int lttng_kconsumerd_take_snapshot(struct lttng_kconsumerd_local_data *ctx, | |
140 | struct lttng_kconsumerd_fd *kconsumerd_fd); | |
141 | ||
142 | /* | |
143 | * Get the produced position | |
144 | * | |
145 | * Returns 0 on success, < 0 on error | |
146 | */ | |
147 | int lttng_kconsumerd_get_produced_snapshot( | |
148 | struct lttng_kconsumerd_local_data *ctx, | |
149 | struct lttng_kconsumerd_fd *kconsumerd_fd, | |
150 | unsigned long *pos); | |
151 | ||
6533b585 DG |
152 | /* |
153 | * Send return code to session daemon. | |
154 | * | |
155 | * Returns the return code of sendmsg : the number of bytes transmitted or -1 | |
156 | * on error. | |
157 | */ | |
158 | extern int lttng_kconsumerd_send_error( | |
159 | struct lttng_kconsumerd_local_data *ctx, int cmd); | |
160 | ||
161 | /* | |
162 | * Poll on the should_quit pipe and the command socket return -1 on error and | |
163 | * should exit, 0 if data is available on the command socket. | |
164 | */ | |
165 | extern int lttng_kconsumerd_poll_socket(struct pollfd *kconsumerd_sockpoll); | |
166 | ||
167 | /* | |
168 | * This thread polls the fds in the ltt_fd_list to consume the data and write | |
169 | * it to tracefile if necessary. | |
170 | */ | |
171 | extern void *lttng_kconsumerd_thread_poll_fds(void *data); | |
172 | ||
173 | /* | |
174 | * This thread listens on the consumerd socket and receives the file | |
175 | * descriptors from ltt-sessiond. | |
176 | */ | |
177 | extern void *lttng_kconsumerd_thread_receive_fds(void *data); | |
178 | ||
179 | /* | |
180 | * Called from signal handler to ensure a clean exit. | |
181 | */ | |
182 | extern void lttng_kconsumerd_should_exit( | |
183 | struct lttng_kconsumerd_local_data *ctx); | |
184 | ||
185 | /* | |
186 | * Cleanup the daemon's socket on exit. | |
187 | */ | |
188 | extern void lttng_kconsumerd_cleanup(void); | |
189 | ||
190 | /* | |
191 | * Set the error socket for communication with a session daemon. | |
192 | */ | |
193 | extern void lttng_kconsumerd_set_error_sock( | |
194 | struct lttng_kconsumerd_local_data *ctx, int sock); | |
195 | ||
196 | /* | |
197 | * Set the command socket path for communication with a session daemon. | |
198 | */ | |
199 | extern void lttng_kconsumerd_set_command_sock_path( | |
200 | struct lttng_kconsumerd_local_data *ctx, char *sock); | |
201 | ||
202 | #endif /* _LTTNG_KCONSUMERD_H */ |