Port: Add OSX support to poll compat
[lttng-tools.git] / src / common / compat / poll.h
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
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.
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 *
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.
16 */
17
18 #ifndef _LTT_POLL_H
19 #define _LTT_POLL_H
20
21 #include <assert.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #include <common/common.h>
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 {
46 free(events);
47 }
48
49 /*
50 * epoll(7) implementation.
51 */
52 #ifdef HAVE_EPOLL
53 #include <sys/epoll.h>
54 #include <stdio.h>
55 #include <features.h>
56 #include <common/compat/fcntl.h>
57
58 /* See man epoll(7) for this define path */
59 #define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
60
61 enum {
62 /* Polling variables compatibility for epoll */
63 LPOLLIN = EPOLLIN,
64 LPOLLPRI = EPOLLPRI,
65 LPOLLOUT = EPOLLOUT,
66 LPOLLRDNORM = EPOLLRDNORM,
67 LPOLLRDBAND = EPOLLRDBAND,
68 LPOLLWRNORM = EPOLLWRNORM,
69 LPOLLWRBAND = EPOLLWRBAND,
70 LPOLLMSG = EPOLLMSG,
71 LPOLLERR = EPOLLERR,
72 LPOLLHUP = EPOLLHUP,
73 LPOLLNVAL = EPOLLHUP,
74 LPOLLRDHUP = EPOLLRDHUP,
75 /* Close on exec feature of epoll */
76 #if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
77 LTTNG_CLOEXEC = EPOLL_CLOEXEC,
78 #else
79 /*
80 * EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
81 * epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
82 * epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
83 * directly to fcntl(..) instead.
84 */
85 LTTNG_CLOEXEC = FD_CLOEXEC,
86 #endif
87 };
88
89 struct compat_epoll_event {
90 int epfd;
91 uint32_t nb_fd; /* Current number of fd in events */
92 uint32_t alloc_size; /* Size of events array */
93 uint32_t init_size; /* Initial size of events array */
94 struct epoll_event *events;
95 };
96 #define lttng_poll_event compat_epoll_event
97
98 static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
99 int index, uint32_t nb_fd)
100 {
101 assert(events);
102 assert(index != nb_fd);
103
104 if (index == 0 || nb_fd == 0) {
105 return -1;
106 } else {
107 return events->events[index - 1].data.fd;
108 }
109 }
110
111 /*
112 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
113 * being the index of the events array.
114 */
115 #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
116 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
117 #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
118 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
119 #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
120 __lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
121
122 /*
123 * Create the epoll set. No memory allocation is done here.
124 */
125 extern int compat_epoll_create(struct lttng_poll_event *events,
126 int size, int flags);
127 #define lttng_poll_create(events, size, flags) \
128 compat_epoll_create(events, size, flags)
129
130 #if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
131 static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
132 int flags)
133 {
134 return epoll_create1(flags);
135 }
136 #else
137 static inline int compat_glibc_epoll_create(int size, int flags)
138 {
139 /*
140 * epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
141 * epoll_create(..) also means that we lose the possibility to
142 * directly set the EPOLL_CLOEXEC, so try and do it anyway but through
143 * fcntl(..).
144 */
145 int efd = epoll_create(size);
146 assert(fcntl(efd, F_SETFD, flags) != -1);
147 return efd;
148 }
149 #endif
150
151 /*
152 * Wait on epoll set with the number of fd registered to the lttng_poll_event
153 * data structure (events).
154 */
155 extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout);
156 #define lttng_poll_wait(events, timeout) \
157 compat_epoll_wait(events, timeout)
158
159 /*
160 * Add a fd to the epoll set and resize the epoll_event structure if needed.
161 */
162 extern int compat_epoll_add(struct lttng_poll_event *events,
163 int fd, uint32_t req_events);
164 #define lttng_poll_add(events, fd, req_events) \
165 compat_epoll_add(events, fd, req_events)
166
167 /*
168 * Remove a fd from the epoll set.
169 */
170 extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
171 #define lttng_poll_del(events, fd) \
172 compat_epoll_del(events, fd)
173
174 /*
175 * Set up the poll set limits variable poll_max_size
176 */
177 extern int compat_epoll_set_max_size(void);
178 #define lttng_poll_set_max_size() \
179 compat_epoll_set_max_size()
180
181 /*
182 * This function memset with zero the structure since it can be reused at each
183 * round of a main loop. Being in a loop and using a non static number of fds,
184 * this function must be called to insure coherent events with associted fds.
185 */
186 static inline void lttng_poll_reset(struct lttng_poll_event *events)
187 {
188 if (events && events->events) {
189 memset(events->events, 0,
190 events->nb_fd * sizeof(struct epoll_event));
191 }
192 }
193
194 /*
195 * Initialize an already allocated poll event data structure. For epoll(), the
196 * epfd is set to -1 to indicate that it's not usable.
197 */
198 static inline void lttng_poll_init(struct lttng_poll_event *events)
199 {
200 memset(events, 0, sizeof(struct lttng_poll_event));
201 /* Set fd to -1 so if clean before created, we don't close 0. */
202 events->epfd = -1;
203 }
204
205 /*
206 * Clean the events structure of a lttng_poll_event. It's the caller
207 * responsability to free the lttng_poll_event memory.
208 */
209 static inline void lttng_poll_clean(struct lttng_poll_event *events)
210 {
211 int ret;
212
213 if (!events) {
214 return;
215 }
216
217 if (events->epfd >= 0) {
218 ret = close(events->epfd);
219 if (ret) {
220 PERROR("close");
221 }
222 }
223
224 __lttng_poll_free((void *) events->events);
225 }
226
227 #else /* HAVE_EPOLL */
228 /*
229 * Fallback on poll(2) API
230 */
231
232 /* Needed for some poll event values */
233 #ifndef __USE_XOPEN
234 #define __USE_XOPEN
235 #endif
236
237 /* Needed for some poll event values */
238 #ifndef __USE_GNU
239 #define __USE_GNU
240 #endif
241
242 #include <poll.h>
243 #include <stdint.h>
244
245 enum {
246 /* Polling variables compatibility for poll */
247 LPOLLIN = POLLIN,
248 LPOLLPRI = POLLPRI,
249 LPOLLOUT = POLLOUT,
250 LPOLLRDNORM = POLLRDNORM,
251 LPOLLRDBAND = POLLRDBAND,
252 LPOLLWRNORM = POLLWRNORM,
253 LPOLLWRBAND = POLLWRBAND,
254 #if __linux__
255 LPOLLMSG = POLLMSG,
256 LPOLLRDHUP = POLLRDHUP,
257 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
258 LPOLLMSG = 0,
259 LPOLLRDHUP = 0,
260 #else
261 #error "Please add support for your OS."
262 #endif /* __linux__ */
263 LPOLLERR = POLLERR,
264 LPOLLHUP = POLLHUP | POLLNVAL,
265 /* Close on exec feature does not exist for poll(2) */
266 LTTNG_CLOEXEC = 0xdead,
267 };
268
269 struct compat_poll_event_array {
270 uint32_t nb_fd; /* Current number of fd in events */
271 uint32_t alloc_size; /* Size of events array */
272 /* Initial size of the pollset. We never shrink below that. */
273 uint32_t init_size;
274 struct pollfd *events;
275 };
276
277 struct compat_poll_event {
278 /*
279 * Modified by the wait action. Updated using current fields if the
280 * need_update flag is set.
281 */
282 struct compat_poll_event_array wait;
283 /*
284 * This is modified by add/del actions being the _current_ flow of
285 * execution before a poll wait is done.
286 */
287 struct compat_poll_event_array current;
288
289 /* Indicate if wait.events need to be updated from current. */
290 int need_update:1;
291 };
292 #define lttng_poll_event compat_poll_event
293
294 static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
295 int index, uint32_t nb_fd)
296 {
297 assert(events);
298 assert(index != nb_fd);
299
300 if (index == 0 || nb_fd == 0) {
301 return -1;
302 } else {
303 return events->current.events[index - 1].fd;
304 }
305 }
306
307 /*
308 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
309 * being the index of the events array.
310 */
311 #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
312 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
313 #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd
314 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
315 #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
316 __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
317
318 /*
319 * Create a pollfd structure of size 'size'.
320 */
321 extern int compat_poll_create(struct lttng_poll_event *events, int size);
322 #define lttng_poll_create(events, size, flags) \
323 compat_poll_create(events, size)
324
325 /*
326 * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
327 * structure.
328 */
329 extern int compat_poll_wait(struct lttng_poll_event *events, int timeout);
330 #define lttng_poll_wait(events, timeout) \
331 compat_poll_wait(events, timeout)
332
333 /*
334 * Add the fd to the pollfd structure. Resize if needed.
335 */
336 extern int compat_poll_add(struct lttng_poll_event *events,
337 int fd, uint32_t req_events);
338 #define lttng_poll_add(events, fd, req_events) \
339 compat_poll_add(events, fd, req_events)
340
341 /*
342 * Remove the fd from the pollfd. Memory allocation is done to recreate a new
343 * pollfd, data is copied from the old pollfd to the new and, finally, the old
344 * one is freed().
345 */
346 extern int compat_poll_del(struct lttng_poll_event *events, int fd);
347 #define lttng_poll_del(events, fd) \
348 compat_poll_del(events, fd)
349
350 /*
351 * Set up the poll set limits variable poll_max_size
352 */
353 extern int compat_poll_set_max_size(void);
354 #define lttng_poll_set_max_size() \
355 compat_poll_set_max_size()
356
357 /*
358 * No need to reset a pollfd structure for poll(2)
359 */
360 static inline void lttng_poll_reset(struct lttng_poll_event *events)
361 {}
362
363 /*
364 * Initialize an already allocated poll event data structure.
365 */
366 static inline void lttng_poll_init(struct lttng_poll_event *events)
367 {
368 memset(events, 0, sizeof(struct lttng_poll_event));
369 }
370
371 /*
372 * Clean the events structure of a lttng_poll_event. It's the caller
373 * responsability to free the lttng_poll_event memory.
374 */
375 static inline void lttng_poll_clean(struct lttng_poll_event *events)
376 {
377 if (events) {
378 __lttng_poll_free((void *) events->wait.events);
379 __lttng_poll_free((void *) events->current.events);
380 }
381 }
382
383 #endif /* HAVE_EPOLL */
384
385 #endif /* _LTT_POLL_H */
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