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5eb91c98 DG |
1 | /* |
2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> | |
3 | * | |
d14d33bf AM |
4 | * This program is free software; you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License, version 2 only, | |
6 | * as published by the Free Software Foundation. | |
5eb91c98 DG |
7 | * |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
d14d33bf AM |
13 | * You should have received a copy of the GNU General Public License along |
14 | * with this program; if not, write to the Free Software Foundation, Inc., | |
15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
5eb91c98 DG |
16 | */ |
17 | ||
18 | #ifndef _LTT_POLL_H | |
19 | #define _LTT_POLL_H | |
20 | ||
beaad64c | 21 | #include <assert.h> |
5eb91c98 DG |
22 | #include <string.h> |
23 | #include <unistd.h> | |
24 | ||
990570ed | 25 | #include <common/common.h> |
5eb91c98 DG |
26 | |
27 | /* | |
28 | * Maximum number of fd we can monitor. | |
29 | * | |
30 | * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will | |
31 | * be used for the maximum size of the poll set. If this interface is not | |
32 | * available, according to the manpage, the max_user_watches value is 1/25 (4%) | |
33 | * of the available low memory divided by the registration cost in bytes which | |
34 | * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel. | |
35 | * | |
36 | * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by | |
37 | * getrlimit(2). | |
38 | */ | |
39 | extern unsigned int poll_max_size; | |
40 | ||
41 | /* | |
42 | * Used by lttng_poll_clean to free the events structure in a lttng_poll_event. | |
43 | */ | |
44 | static inline void __lttng_poll_free(void *events) | |
45 | { | |
0e428499 | 46 | free(events); |
5eb91c98 DG |
47 | } |
48 | ||
49 | /* | |
50 | * epoll(7) implementation. | |
51 | */ | |
52 | #ifdef HAVE_EPOLL | |
53 | #include <sys/epoll.h> | |
76d7553f | 54 | #include <stdio.h> |
5eb91c98 DG |
55 | |
56 | /* See man epoll(7) for this define path */ | |
990570ed | 57 | #define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches" |
5eb91c98 DG |
58 | |
59 | enum { | |
60 | /* Polling variables compatibility for epoll */ | |
61 | LPOLLIN = EPOLLIN, | |
62 | LPOLLPRI = EPOLLPRI, | |
63 | LPOLLOUT = EPOLLOUT, | |
64 | LPOLLRDNORM = EPOLLRDNORM, | |
65 | LPOLLRDBAND = EPOLLRDBAND, | |
66 | LPOLLWRNORM = EPOLLWRNORM, | |
67 | LPOLLWRBAND = EPOLLWRBAND, | |
68 | LPOLLMSG = EPOLLMSG, | |
69 | LPOLLERR = EPOLLERR, | |
70 | LPOLLHUP = EPOLLHUP, | |
71 | LPOLLNVAL = EPOLLHUP, | |
72 | LPOLLRDHUP = EPOLLRDHUP, | |
73 | /* Close on exec feature of epoll */ | |
74 | LTTNG_CLOEXEC = EPOLL_CLOEXEC, | |
75 | }; | |
76 | ||
77 | struct compat_epoll_event { | |
78 | int epfd; | |
79 | uint32_t nb_fd; /* Current number of fd in events */ | |
d21b0d71 DG |
80 | uint32_t alloc_size; /* Size of events array */ |
81 | uint32_t init_size; /* Initial size of events array */ | |
5eb91c98 DG |
82 | struct epoll_event *events; |
83 | }; | |
84 | #define lttng_poll_event compat_epoll_event | |
85 | ||
beaad64c DG |
86 | static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events, |
87 | int index, uint32_t nb_fd) | |
88 | { | |
89 | assert(events); | |
90 | assert(index != nb_fd); | |
91 | ||
92 | if (index == 0 || nb_fd == 0) { | |
93 | return -1; | |
94 | } else { | |
95 | return events->events[index - 1].data.fd; | |
96 | } | |
97 | } | |
98 | ||
5eb91c98 DG |
99 | /* |
100 | * For the following calls, consider 'e' to be a lttng_poll_event pointer and i | |
101 | * being the index of the events array. | |
102 | */ | |
103 | #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd | |
104 | #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events | |
105 | #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd | |
106 | #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size | |
beaad64c DG |
107 | #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \ |
108 | __lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd) | |
5eb91c98 DG |
109 | |
110 | /* | |
111 | * Create the epoll set. No memory allocation is done here. | |
112 | */ | |
113 | extern int compat_epoll_create(struct lttng_poll_event *events, | |
114 | int size, int flags); | |
115 | #define lttng_poll_create(events, size, flags) \ | |
65b1b198 | 116 | compat_epoll_create(events, size, flags) |
5eb91c98 DG |
117 | |
118 | /* | |
119 | * Wait on epoll set with the number of fd registered to the lttng_poll_event | |
120 | * data structure (events). | |
121 | */ | |
122 | extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout); | |
123 | #define lttng_poll_wait(events, timeout) \ | |
65b1b198 | 124 | compat_epoll_wait(events, timeout) |
5eb91c98 DG |
125 | |
126 | /* | |
127 | * Add a fd to the epoll set and resize the epoll_event structure if needed. | |
128 | */ | |
129 | extern int compat_epoll_add(struct lttng_poll_event *events, | |
130 | int fd, uint32_t req_events); | |
131 | #define lttng_poll_add(events, fd, req_events) \ | |
65b1b198 | 132 | compat_epoll_add(events, fd, req_events) |
5eb91c98 DG |
133 | |
134 | /* | |
135 | * Remove a fd from the epoll set. | |
136 | */ | |
137 | extern int compat_epoll_del(struct lttng_poll_event *events, int fd); | |
138 | #define lttng_poll_del(events, fd) \ | |
65b1b198 | 139 | compat_epoll_del(events, fd) |
5eb91c98 DG |
140 | |
141 | /* | |
142 | * Set up the poll set limits variable poll_max_size | |
143 | */ | |
144 | extern void compat_epoll_set_max_size(void); | |
65b1b198 MD |
145 | #define lttng_poll_set_max_size() \ |
146 | compat_epoll_set_max_size() | |
5eb91c98 DG |
147 | |
148 | /* | |
149 | * This function memset with zero the structure since it can be reused at each | |
150 | * round of a main loop. Being in a loop and using a non static number of fds, | |
151 | * this function must be called to insure coherent events with associted fds. | |
152 | */ | |
153 | static inline void lttng_poll_reset(struct lttng_poll_event *events) | |
154 | { | |
155 | if (events && events->events) { | |
156 | memset(events->events, 0, | |
157 | events->nb_fd * sizeof(struct epoll_event)); | |
158 | } | |
159 | } | |
160 | ||
161 | /* | |
162 | * Clean the events structure of a lttng_poll_event. It's the caller | |
163 | * responsability to free the lttng_poll_event memory. | |
164 | */ | |
165 | static inline void lttng_poll_clean(struct lttng_poll_event *events) | |
166 | { | |
76d7553f MD |
167 | int ret; |
168 | ||
3cc04881 DG |
169 | if (!events) { |
170 | return; | |
171 | } | |
172 | ||
173 | if (events->epfd >= 0) { | |
76d7553f MD |
174 | ret = close(events->epfd); |
175 | if (ret) { | |
176 | perror("close"); | |
177 | } | |
5eb91c98 | 178 | } |
3cc04881 DG |
179 | |
180 | __lttng_poll_free((void *) events->events); | |
5eb91c98 DG |
181 | } |
182 | ||
183 | #else /* HAVE_EPOLL */ | |
184 | /* | |
185 | * Fallback on poll(2) API | |
186 | */ | |
187 | ||
188 | /* Needed for some poll event values */ | |
189 | #ifndef __USE_XOPEN | |
190 | #define __USE_XOPEN | |
191 | #endif | |
192 | ||
193 | /* Needed for some poll event values */ | |
194 | #ifndef __USE_GNU | |
195 | #define __USE_GNU | |
196 | #endif | |
197 | ||
198 | #include <poll.h> | |
199 | #include <stdint.h> | |
200 | ||
201 | enum { | |
202 | /* Polling variables compatibility for poll */ | |
203 | LPOLLIN = POLLIN, | |
204 | LPOLLPRI = POLLPRI, | |
205 | LPOLLOUT = POLLOUT, | |
206 | LPOLLRDNORM = POLLRDNORM, | |
207 | LPOLLRDBAND = POLLRDBAND, | |
208 | LPOLLWRNORM = POLLWRNORM, | |
209 | LPOLLWRBAND = POLLWRBAND, | |
1268b9d6 | 210 | #if __linux__ |
5eb91c98 | 211 | LPOLLMSG = POLLMSG, |
1268b9d6 | 212 | LPOLLRDHUP = POLLRDHUP, |
3247be18 | 213 | #elif (defined(__FreeBSD__) || defined(__CYGWIN__)) |
1268b9d6 DG |
214 | LPOLLMSG = 0, |
215 | LPOLLRDHUP = 0, | |
b2c3836f MD |
216 | #else |
217 | #error "Please add support for your OS." | |
1268b9d6 | 218 | #endif /* __linux__ */ |
5eb91c98 DG |
219 | LPOLLERR = POLLERR, |
220 | LPOLLHUP = POLLHUP | POLLNVAL, | |
5eb91c98 DG |
221 | /* Close on exec feature does not exist for poll(2) */ |
222 | LTTNG_CLOEXEC = 0xdead, | |
223 | }; | |
224 | ||
d21b0d71 | 225 | struct compat_poll_event_array { |
5eb91c98 | 226 | uint32_t nb_fd; /* Current number of fd in events */ |
d21b0d71 DG |
227 | uint32_t alloc_size; /* Size of events array */ |
228 | /* Initial size of the pollset. We never shrink below that. */ | |
229 | uint32_t init_size; | |
5eb91c98 DG |
230 | struct pollfd *events; |
231 | }; | |
d21b0d71 DG |
232 | |
233 | struct compat_poll_event { | |
234 | /* | |
235 | * Modified by the wait action. Updated using current fields if the | |
236 | * need_update flag is set. | |
237 | */ | |
238 | struct compat_poll_event_array wait; | |
239 | /* | |
240 | * This is modified by add/del actions being the _current_ flow of | |
241 | * execution before a poll wait is done. | |
242 | */ | |
243 | struct compat_poll_event_array current; | |
244 | /* Indicate if wait.events needs to be realloc. */ | |
245 | int need_realloc:1; | |
246 | /* Indicate if wait.events need to be updated from current. */ | |
247 | int need_update:1; | |
248 | }; | |
5eb91c98 DG |
249 | #define lttng_poll_event compat_poll_event |
250 | ||
beaad64c DG |
251 | static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events, |
252 | int index, uint32_t nb_fd) | |
253 | { | |
254 | assert(events); | |
255 | assert(index != nb_fd); | |
256 | ||
257 | if (index == 0 || nb_fd == 0) { | |
258 | return -1; | |
259 | } else { | |
260 | return events->current.events[index - 1].fd; | |
261 | } | |
262 | } | |
263 | ||
5eb91c98 DG |
264 | /* |
265 | * For the following calls, consider 'e' to be a lttng_poll_event pointer and i | |
266 | * being the index of the events array. | |
267 | */ | |
d21b0d71 DG |
268 | #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd |
269 | #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents | |
270 | #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd | |
271 | #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size | |
beaad64c DG |
272 | #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \ |
273 | __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd) | |
5eb91c98 DG |
274 | |
275 | /* | |
276 | * Create a pollfd structure of size 'size'. | |
277 | */ | |
278 | extern int compat_poll_create(struct lttng_poll_event *events, int size); | |
279 | #define lttng_poll_create(events, size, flags) \ | |
65b1b198 | 280 | compat_poll_create(events, size) |
5eb91c98 DG |
281 | |
282 | /* | |
283 | * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data | |
284 | * structure. | |
285 | */ | |
286 | extern int compat_poll_wait(struct lttng_poll_event *events, int timeout); | |
287 | #define lttng_poll_wait(events, timeout) \ | |
65b1b198 | 288 | compat_poll_wait(events, timeout) |
5eb91c98 DG |
289 | |
290 | /* | |
291 | * Add the fd to the pollfd structure. Resize if needed. | |
292 | */ | |
293 | extern int compat_poll_add(struct lttng_poll_event *events, | |
294 | int fd, uint32_t req_events); | |
295 | #define lttng_poll_add(events, fd, req_events) \ | |
65b1b198 | 296 | compat_poll_add(events, fd, req_events) |
5eb91c98 DG |
297 | |
298 | /* | |
299 | * Remove the fd from the pollfd. Memory allocation is done to recreate a new | |
300 | * pollfd, data is copied from the old pollfd to the new and, finally, the old | |
301 | * one is freed(). | |
302 | */ | |
303 | extern int compat_poll_del(struct lttng_poll_event *events, int fd); | |
304 | #define lttng_poll_del(events, fd) \ | |
65b1b198 | 305 | compat_poll_del(events, fd) |
5eb91c98 DG |
306 | |
307 | /* | |
308 | * Set up the poll set limits variable poll_max_size | |
309 | */ | |
310 | extern void compat_poll_set_max_size(void); | |
65b1b198 MD |
311 | #define lttng_poll_set_max_size() \ |
312 | compat_poll_set_max_size() | |
5eb91c98 DG |
313 | |
314 | /* | |
315 | * No need to reset a pollfd structure for poll(2) | |
316 | */ | |
317 | static inline void lttng_poll_reset(struct lttng_poll_event *events) | |
318 | {} | |
319 | ||
320 | /* | |
321 | * Clean the events structure of a lttng_poll_event. It's the caller | |
322 | * responsability to free the lttng_poll_event memory. | |
323 | */ | |
324 | static inline void lttng_poll_clean(struct lttng_poll_event *events) | |
325 | { | |
326 | if (events) { | |
d21b0d71 DG |
327 | __lttng_poll_free((void *) events->wait.events); |
328 | __lttng_poll_free((void *) events->current.events); | |
5eb91c98 DG |
329 | } |
330 | } | |
331 | ||
332 | #endif /* HAVE_EPOLL */ | |
333 | ||
334 | #endif /* _LTT_POLL_H */ |