2 * Copyright (C) 2011 EfficiOS Inc.
4 * SPDX-License-Identifier: LGPL-2.1-only
14 #include <common/common.hpp>
17 * Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
19 static inline void __lttng_poll_free(void *events)
25 * epoll(7) implementation.
28 #include <sys/epoll.h>
31 #include <common/compat/fcntl.hpp>
33 /* See man epoll(7) for this define path */
34 #define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
37 /* Polling variables compatibility for epoll */
41 LPOLLRDNORM = EPOLLRDNORM,
42 LPOLLRDBAND = EPOLLRDBAND,
43 LPOLLWRNORM = EPOLLWRNORM,
44 LPOLLWRBAND = EPOLLWRBAND,
49 LPOLLRDHUP = EPOLLRDHUP,
50 /* Close on exec feature of epoll */
51 #if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
52 LTTNG_CLOEXEC = EPOLL_CLOEXEC,
55 * EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
56 * epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
57 * epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
58 * directly to fcntl(..) instead.
60 LTTNG_CLOEXEC = FD_CLOEXEC,
64 struct compat_epoll_event {
66 uint32_t nb_fd; /* Current number of fd in events */
67 uint32_t alloc_size; /* Size of events array */
68 uint32_t init_size; /* Initial size of events array */
69 struct epoll_event *events;
71 #define lttng_poll_event compat_epoll_event
73 static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
74 int index, uint32_t nb_fd)
77 LTTNG_ASSERT(index != nb_fd);
79 if (index == 0 || nb_fd == 0) {
82 return events->events[index - 1].data.fd;
87 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
88 * being the index of the events array.
90 #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
91 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
92 #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
93 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
94 #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
95 __lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
97 /* Create the epoll set. */
98 extern int compat_epoll_create(struct lttng_poll_event *events,
100 #define lttng_poll_create(events, size, flags) \
101 compat_epoll_create(events, size, flags)
103 #if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
104 static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
107 return epoll_create1(flags);
110 static inline int compat_glibc_epoll_create(int size, int flags)
113 * epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
114 * epoll_create(..) also means that we lose the possibility to
115 * directly set the EPOLL_CLOEXEC, so try and do it anyway but through
118 int efd = epoll_create(size);
119 LTTNG_ASSERT(fcntl(efd, F_SETFD, flags) != -1);
125 * Wait on epoll set with the number of fd registered to the lttng_poll_event
126 * data structure (events).
128 extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
130 #define lttng_poll_wait(events, timeout) \
131 compat_epoll_wait(events, timeout, false)
132 #define lttng_poll_wait_interruptible(events, timeout) \
133 compat_epoll_wait(events, timeout, true)
136 * Add a fd to the epoll set and resize the epoll_event structure if needed.
138 extern int compat_epoll_add(struct lttng_poll_event *events,
139 int fd, uint32_t req_events);
140 #define lttng_poll_add(events, fd, req_events) \
141 compat_epoll_add(events, fd, req_events)
144 * Remove a fd from the epoll set.
146 extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
147 #define lttng_poll_del(events, fd) \
148 compat_epoll_del(events, fd)
151 * Modify an fd's events in the epoll set.
153 extern int compat_epoll_mod(struct lttng_poll_event *events,
154 int fd, uint32_t req_events);
155 #define lttng_poll_mod(events, fd, req_events) \
156 compat_epoll_mod(events, fd, req_events)
159 * Set up the poll set limits variable poll_max_size
161 extern int compat_epoll_set_max_size(void);
162 #define lttng_poll_set_max_size() \
163 compat_epoll_set_max_size()
166 * This function memset with zero the structure since it can be reused at each
167 * round of a main loop. Being in a loop and using a non static number of fds,
168 * this function must be called to insure coherent events with associted fds.
170 static inline void lttng_poll_reset(struct lttng_poll_event *events)
172 if (events && events->events) {
173 memset(events->events, 0,
174 events->nb_fd * sizeof(struct epoll_event));
179 * Initialize an already allocated poll event data structure. For epoll(), the
180 * epfd is set to -1 to indicate that it's not usable.
182 static inline void lttng_poll_init(struct lttng_poll_event *events)
184 memset(events, 0, sizeof(struct lttng_poll_event));
185 /* Set fd to -1 so if clean before created, we don't close 0. */
190 * Clean the events structure of a lttng_poll_event. It's the caller
191 * responsability to free the lttng_poll_event memory.
193 static inline void lttng_poll_clean(struct lttng_poll_event *events)
201 if (events->epfd >= 0) {
202 ret = close(events->epfd);
208 __lttng_poll_free((void *) events->events);
211 #else /* HAVE_EPOLL */
213 * Fallback on poll(2) API
216 /* Needed for some poll event values */
221 /* Needed for some poll event values */
230 /* Polling variables compatibility for poll */
234 LPOLLRDNORM = POLLRDNORM,
235 LPOLLRDBAND = POLLRDBAND,
236 LPOLLWRNORM = POLLWRNORM,
237 LPOLLWRBAND = POLLWRBAND,
240 LPOLLRDHUP = POLLRDHUP,
241 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
245 #error "Please add support for your OS."
246 #endif /* __linux__ */
248 LPOLLHUP = POLLHUP | POLLNVAL,
249 /* Close on exec feature does not exist for poll(2) */
250 LTTNG_CLOEXEC = 0xdead,
253 struct compat_poll_event_array {
254 uint32_t nb_fd; /* Current number of fd in events */
255 uint32_t alloc_size; /* Size of events array */
256 /* Initial size of the pollset. We never shrink below that. */
258 struct pollfd *events;
261 struct compat_poll_event {
263 * Modified by the wait action. Updated using current fields if the
264 * need_update flag is set.
266 struct compat_poll_event_array wait;
268 * This is modified by add/del actions being the _current_ flow of
269 * execution before a poll wait is done.
271 struct compat_poll_event_array current;
273 /* Indicate if wait.events need to be updated from current. */
276 #define lttng_poll_event compat_poll_event
278 static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
279 int index, uint32_t nb_fd)
281 LTTNG_ASSERT(events);
282 LTTNG_ASSERT(index != nb_fd);
284 if (index == 0 || nb_fd == 0) {
287 return events->current.events[index - 1].fd;
292 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
293 * being the index of the events array.
294 * LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
295 * current list for test compatibility purposes.
297 #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
298 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
299 #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
300 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
301 #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
302 __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
305 * Create a pollfd structure of size 'size'.
307 extern int compat_poll_create(struct lttng_poll_event *events, int size);
308 #define lttng_poll_create(events, size, flags) \
309 compat_poll_create(events, size)
312 * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
315 extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
317 #define lttng_poll_wait(events, timeout) \
318 compat_poll_wait(events, timeout, false)
319 #define lttng_poll_wait_interruptible(events, timeout) \
320 compat_poll_wait(events, timeout, true)
323 * Add the fd to the pollfd structure. Resize if needed.
325 extern int compat_poll_add(struct lttng_poll_event *events,
326 int fd, uint32_t req_events);
327 #define lttng_poll_add(events, fd, req_events) \
328 compat_poll_add(events, fd, req_events)
331 * Remove the fd from the pollfd. Memory allocation is done to recreate a new
332 * pollfd, data is copied from the old pollfd to the new and, finally, the old
335 extern int compat_poll_del(struct lttng_poll_event *events, int fd);
336 #define lttng_poll_del(events, fd) \
337 compat_poll_del(events, fd)
340 * Modify an fd's events in the poll set.
342 extern int compat_poll_mod(struct lttng_poll_event *events,
343 int fd, uint32_t req_events);
344 #define lttng_poll_mod(events, fd, req_events) \
345 compat_poll_mod(events, fd, req_events)
348 * Set up the poll set limits variable poll_max_size
350 extern int compat_poll_set_max_size(void);
351 #define lttng_poll_set_max_size() \
352 compat_poll_set_max_size()
355 * No need to reset a pollfd structure for poll(2)
357 static inline void lttng_poll_reset(
358 struct lttng_poll_event *events __attribute__((unused)))
362 * Initialize an already allocated poll event data structure.
364 static inline void lttng_poll_init(struct lttng_poll_event *events)
366 memset(events, 0, sizeof(struct lttng_poll_event));
370 * Clean the events structure of a lttng_poll_event. It's the caller
371 * responsability to free the lttng_poll_event memory.
373 static inline void lttng_poll_clean(struct lttng_poll_event *events)
376 __lttng_poll_free((void *) events->wait.events);
377 __lttng_poll_free((void *) events->current.events);
381 #endif /* HAVE_EPOLL */
383 #endif /* _LTT_POLL_H */