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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 | ||
6d737ce4 DG |
161 | /* |
162 | * Initialize an already allocated poll event data structure. For epoll(), the | |
163 | * epfd is set to -1 to indicate that it's not usable. | |
164 | */ | |
165 | static inline void lttng_poll_init(struct lttng_poll_event *events) | |
166 | { | |
c5854b1c | 167 | memset(events, 0, sizeof(struct lttng_poll_event)); |
6d737ce4 DG |
168 | /* Set fd to -1 so if clean before created, we don't close 0. */ |
169 | events->epfd = -1; | |
170 | } | |
171 | ||
5eb91c98 DG |
172 | /* |
173 | * Clean the events structure of a lttng_poll_event. It's the caller | |
174 | * responsability to free the lttng_poll_event memory. | |
175 | */ | |
176 | static inline void lttng_poll_clean(struct lttng_poll_event *events) | |
177 | { | |
76d7553f MD |
178 | int ret; |
179 | ||
3cc04881 DG |
180 | if (!events) { |
181 | return; | |
182 | } | |
183 | ||
184 | if (events->epfd >= 0) { | |
76d7553f MD |
185 | ret = close(events->epfd); |
186 | if (ret) { | |
187 | perror("close"); | |
188 | } | |
5eb91c98 | 189 | } |
3cc04881 DG |
190 | |
191 | __lttng_poll_free((void *) events->events); | |
5eb91c98 DG |
192 | } |
193 | ||
194 | #else /* HAVE_EPOLL */ | |
195 | /* | |
196 | * Fallback on poll(2) API | |
197 | */ | |
198 | ||
199 | /* Needed for some poll event values */ | |
200 | #ifndef __USE_XOPEN | |
201 | #define __USE_XOPEN | |
202 | #endif | |
203 | ||
204 | /* Needed for some poll event values */ | |
205 | #ifndef __USE_GNU | |
206 | #define __USE_GNU | |
207 | #endif | |
208 | ||
209 | #include <poll.h> | |
210 | #include <stdint.h> | |
211 | ||
212 | enum { | |
213 | /* Polling variables compatibility for poll */ | |
214 | LPOLLIN = POLLIN, | |
215 | LPOLLPRI = POLLPRI, | |
216 | LPOLLOUT = POLLOUT, | |
217 | LPOLLRDNORM = POLLRDNORM, | |
218 | LPOLLRDBAND = POLLRDBAND, | |
219 | LPOLLWRNORM = POLLWRNORM, | |
220 | LPOLLWRBAND = POLLWRBAND, | |
1268b9d6 | 221 | #if __linux__ |
5eb91c98 | 222 | LPOLLMSG = POLLMSG, |
1268b9d6 | 223 | LPOLLRDHUP = POLLRDHUP, |
3247be18 | 224 | #elif (defined(__FreeBSD__) || defined(__CYGWIN__)) |
1268b9d6 DG |
225 | LPOLLMSG = 0, |
226 | LPOLLRDHUP = 0, | |
b2c3836f MD |
227 | #else |
228 | #error "Please add support for your OS." | |
1268b9d6 | 229 | #endif /* __linux__ */ |
5eb91c98 DG |
230 | LPOLLERR = POLLERR, |
231 | LPOLLHUP = POLLHUP | POLLNVAL, | |
5eb91c98 DG |
232 | /* Close on exec feature does not exist for poll(2) */ |
233 | LTTNG_CLOEXEC = 0xdead, | |
234 | }; | |
235 | ||
d21b0d71 | 236 | struct compat_poll_event_array { |
5eb91c98 | 237 | uint32_t nb_fd; /* Current number of fd in events */ |
d21b0d71 DG |
238 | uint32_t alloc_size; /* Size of events array */ |
239 | /* Initial size of the pollset. We never shrink below that. */ | |
240 | uint32_t init_size; | |
5eb91c98 DG |
241 | struct pollfd *events; |
242 | }; | |
d21b0d71 DG |
243 | |
244 | struct compat_poll_event { | |
245 | /* | |
246 | * Modified by the wait action. Updated using current fields if the | |
247 | * need_update flag is set. | |
248 | */ | |
249 | struct compat_poll_event_array wait; | |
250 | /* | |
251 | * This is modified by add/del actions being the _current_ flow of | |
252 | * execution before a poll wait is done. | |
253 | */ | |
254 | struct compat_poll_event_array current; | |
255 | /* Indicate if wait.events needs to be realloc. */ | |
256 | int need_realloc:1; | |
257 | /* Indicate if wait.events need to be updated from current. */ | |
258 | int need_update:1; | |
259 | }; | |
5eb91c98 DG |
260 | #define lttng_poll_event compat_poll_event |
261 | ||
beaad64c DG |
262 | static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events, |
263 | int index, uint32_t nb_fd) | |
264 | { | |
265 | assert(events); | |
266 | assert(index != nb_fd); | |
267 | ||
268 | if (index == 0 || nb_fd == 0) { | |
269 | return -1; | |
270 | } else { | |
271 | return events->current.events[index - 1].fd; | |
272 | } | |
273 | } | |
274 | ||
5eb91c98 DG |
275 | /* |
276 | * For the following calls, consider 'e' to be a lttng_poll_event pointer and i | |
277 | * being the index of the events array. | |
278 | */ | |
d21b0d71 DG |
279 | #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd |
280 | #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents | |
281 | #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd | |
282 | #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size | |
beaad64c DG |
283 | #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \ |
284 | __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd) | |
5eb91c98 DG |
285 | |
286 | /* | |
287 | * Create a pollfd structure of size 'size'. | |
288 | */ | |
289 | extern int compat_poll_create(struct lttng_poll_event *events, int size); | |
290 | #define lttng_poll_create(events, size, flags) \ | |
65b1b198 | 291 | compat_poll_create(events, size) |
5eb91c98 DG |
292 | |
293 | /* | |
294 | * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data | |
295 | * structure. | |
296 | */ | |
297 | extern int compat_poll_wait(struct lttng_poll_event *events, int timeout); | |
298 | #define lttng_poll_wait(events, timeout) \ | |
65b1b198 | 299 | compat_poll_wait(events, timeout) |
5eb91c98 DG |
300 | |
301 | /* | |
302 | * Add the fd to the pollfd structure. Resize if needed. | |
303 | */ | |
304 | extern int compat_poll_add(struct lttng_poll_event *events, | |
305 | int fd, uint32_t req_events); | |
306 | #define lttng_poll_add(events, fd, req_events) \ | |
65b1b198 | 307 | compat_poll_add(events, fd, req_events) |
5eb91c98 DG |
308 | |
309 | /* | |
310 | * Remove the fd from the pollfd. Memory allocation is done to recreate a new | |
311 | * pollfd, data is copied from the old pollfd to the new and, finally, the old | |
312 | * one is freed(). | |
313 | */ | |
314 | extern int compat_poll_del(struct lttng_poll_event *events, int fd); | |
315 | #define lttng_poll_del(events, fd) \ | |
65b1b198 | 316 | compat_poll_del(events, fd) |
5eb91c98 DG |
317 | |
318 | /* | |
319 | * Set up the poll set limits variable poll_max_size | |
320 | */ | |
321 | extern void compat_poll_set_max_size(void); | |
65b1b198 MD |
322 | #define lttng_poll_set_max_size() \ |
323 | compat_poll_set_max_size() | |
5eb91c98 DG |
324 | |
325 | /* | |
326 | * No need to reset a pollfd structure for poll(2) | |
327 | */ | |
328 | static inline void lttng_poll_reset(struct lttng_poll_event *events) | |
329 | {} | |
330 | ||
6d737ce4 DG |
331 | /* |
332 | * Initialize an already allocated poll event data structure. | |
333 | */ | |
334 | static inline void lttng_poll_init(struct lttng_poll_event *events) | |
335 | { | |
336 | memset(events, 0, sizeof(struct lttng_poll_event)); | |
337 | } | |
338 | ||
5eb91c98 DG |
339 | /* |
340 | * Clean the events structure of a lttng_poll_event. It's the caller | |
341 | * responsability to free the lttng_poll_event memory. | |
342 | */ | |
343 | static inline void lttng_poll_clean(struct lttng_poll_event *events) | |
344 | { | |
345 | if (events) { | |
d21b0d71 DG |
346 | __lttng_poll_free((void *) events->wait.events); |
347 | __lttng_poll_free((void *) events->current.events); | |
5eb91c98 DG |
348 | } |
349 | } | |
350 | ||
351 | #endif /* HAVE_EPOLL */ | |
352 | ||
353 | #endif /* _LTT_POLL_H */ |