[lttng-tools.git] / src / common / compat / poll.h

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _LTT_POLL_H
#define _LTT_POLL_H

#include <assert.h>
#include <string.h>
#include <unistd.h>

#include <common/common.h>

/*
 * Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
 */
static inline void __lttng_poll_free(void *events)
{
	free(events);
}

/*
 * epoll(7) implementation.
 */
#ifdef HAVE_EPOLL
#include <sys/epoll.h>
#include <stdio.h>
#include <features.h>
#include <common/compat/fcntl.h>

/* See man epoll(7) for this define path */
#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"

enum {
	/* Polling variables compatibility for epoll */
	LPOLLIN = EPOLLIN,
	LPOLLPRI = EPOLLPRI,
	LPOLLOUT = EPOLLOUT,
	LPOLLRDNORM = EPOLLRDNORM,
	LPOLLRDBAND = EPOLLRDBAND,
	LPOLLWRNORM = EPOLLWRNORM,
	LPOLLWRBAND = EPOLLWRBAND,
	LPOLLMSG = EPOLLMSG,
	LPOLLERR = EPOLLERR,
	LPOLLHUP = EPOLLHUP,
	LPOLLNVAL = EPOLLHUP,
	LPOLLRDHUP = EPOLLRDHUP,
	/* Close on exec feature of epoll */
#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
#else
	/*
	 * EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
	 * epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
	 * epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
	 * directly to fcntl(..) instead.
	 */
	LTTNG_CLOEXEC = FD_CLOEXEC,
#endif
};

struct compat_epoll_event {
	int epfd;
	uint32_t nb_fd;       /* Current number of fd in events */
	uint32_t alloc_size; /* Size of events array */
	uint32_t init_size;	/* Initial size of events array */
	struct epoll_event *events;
};
#define lttng_poll_event compat_epoll_event

static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
		int index, uint32_t nb_fd)
{
	assert(events);
	assert(index != nb_fd);

	if (index == 0 || nb_fd == 0) {
		return -1;
	} else {
		return events->events[index - 1].data.fd;
	}
}

/*
 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
 * being the index of the events array.
 */
#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)

/* Create the epoll set. */
extern int compat_epoll_create(struct lttng_poll_event *events,
		int size, int flags);
#define lttng_poll_create(events, size, flags) \
	compat_epoll_create(events, size, flags)

#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
		int flags)
{
	return epoll_create1(flags);
}
#else
static inline int compat_glibc_epoll_create(int size, int flags)
{
	/*
	 * epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	 * epoll_create(..) also means that we lose the possibility to
	 * directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	 * fcntl(..).
	 */
	int efd = epoll_create(size);
	assert(fcntl(efd, F_SETFD, flags) != -1);
	return efd;
}
#endif

/*
 * Wait on epoll set with the number of fd registered to the lttng_poll_event
 * data structure (events).
 */
extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
		bool interruptible);
#define lttng_poll_wait(events, timeout) \
	compat_epoll_wait(events, timeout, false)
#define lttng_poll_wait_interruptible(events, timeout) \
	compat_epoll_wait(events, timeout, true)

/*
 * Add a fd to the epoll set and resize the epoll_event structure if needed.
 */
extern int compat_epoll_add(struct lttng_poll_event *events,
		int fd, uint32_t req_events);
#define lttng_poll_add(events, fd, req_events) \
	compat_epoll_add(events, fd, req_events)

/*
 * Remove a fd from the epoll set.
 */
extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
#define lttng_poll_del(events, fd) \
	compat_epoll_del(events, fd)

/*
 * Modify an fd's events in the epoll set.
 */
extern int compat_epoll_mod(struct lttng_poll_event *events,
		int fd, uint32_t req_events);
#define lttng_poll_mod(events, fd, req_events) \
	compat_epoll_mod(events, fd, req_events)

/*
 * Set up the poll set limits variable poll_max_size
 */
extern int compat_epoll_set_max_size(void);
#define lttng_poll_set_max_size() \
	compat_epoll_set_max_size()

/*
 * This function memset with zero the structure since it can be reused at each
 * round of a main loop. Being in a loop and using a non static number of fds,
 * this function must be called to insure coherent events with associted fds.
 */
static inline void lttng_poll_reset(struct lttng_poll_event *events)
{
	if (events && events->events) {
		memset(events->events, 0,
				events->nb_fd * sizeof(struct epoll_event));
	}
}

/*
 * Initialize an already allocated poll event data structure. For epoll(), the
 * epfd is set to -1 to indicate that it's not usable.
 */
static inline void lttng_poll_init(struct lttng_poll_event *events)
{
	memset(events, 0, sizeof(struct lttng_poll_event));
	/* Set fd to -1 so if clean before created, we don't close 0. */
	events->epfd = -1;
}

/*
 * Clean the events structure of a lttng_poll_event. It's the caller
 * responsability to free the lttng_poll_event memory.
 */
static inline void lttng_poll_clean(struct lttng_poll_event *events)
{
	int ret;

	if (!events) {
		return;
	}

	if (events->epfd >= 0) {
		ret = close(events->epfd);
		if (ret) {
			PERROR("close");
		}
	}

	__lttng_poll_free((void *) events->events);
}

#else	/* HAVE_EPOLL */
/*
 * Fallback on poll(2) API
 */

/* Needed for some poll event values */
#ifndef __USE_XOPEN
#define __USE_XOPEN
#endif

/* Needed for some poll event values */
#ifndef __USE_GNU
#define __USE_GNU
#endif

#include <poll.h>
#include <stdint.h>

enum {
	/* Polling variables compatibility for poll */
	LPOLLIN = POLLIN,
	LPOLLPRI = POLLPRI,
	LPOLLOUT = POLLOUT,
	LPOLLRDNORM = POLLRDNORM,
	LPOLLRDBAND = POLLRDBAND,
	LPOLLWRNORM = POLLWRNORM,
	LPOLLWRBAND = POLLWRBAND,
#if __linux__
	LPOLLMSG = POLLMSG,
	LPOLLRDHUP = POLLRDHUP,
#elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
	LPOLLMSG = 0,
	LPOLLRDHUP = 0,
#else
#error "Please add support for your OS."
#endif /* __linux__ */
	LPOLLERR = POLLERR,
	LPOLLHUP = POLLHUP | POLLNVAL,
	/* Close on exec feature does not exist for poll(2) */
	LTTNG_CLOEXEC = 0xdead,
};

struct compat_poll_event_array {
	uint32_t nb_fd;       /* Current number of fd in events */
	uint32_t alloc_size; /* Size of events array */
	/* Initial size of the pollset. We never shrink below that. */
	uint32_t init_size;
	struct pollfd *events;
};

struct compat_poll_event {
	/*
	 * Modified by the wait action. Updated using current fields if the
	 * need_update flag is set.
	 */
	struct compat_poll_event_array wait;
	/*
	 * This is modified by add/del actions being the _current_ flow of
	 * execution before a poll wait is done.
	 */
	struct compat_poll_event_array current;

	/* Indicate if wait.events need to be updated from current. */
	int need_update:1;
};
#define lttng_poll_event compat_poll_event

static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
		int index, uint32_t nb_fd)
{
	assert(events);
	assert(index != nb_fd);

	if (index == 0 || nb_fd == 0) {
		return -1;
	} else {
		return events->current.events[index - 1].fd;
	}
}

/*
 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
 * being the index of the events array.
 * LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
 * current list for test compatibility purposes.
 */
#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)

/*
 * Create a pollfd structure of size 'size'.
 */
extern int compat_poll_create(struct lttng_poll_event *events, int size);
#define lttng_poll_create(events, size, flags) \
	compat_poll_create(events, size)

/*
 * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
 * structure.
 */
extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
		bool interruptible);
#define lttng_poll_wait(events, timeout) \
	compat_poll_wait(events, timeout, false)
#define lttng_poll_wait_interruptible(events, timeout) \
	compat_poll_wait(events, timeout, true)

/*
 * Add the fd to the pollfd structure. Resize if needed.
 */
extern int compat_poll_add(struct lttng_poll_event *events,
		int fd, uint32_t req_events);
#define lttng_poll_add(events, fd, req_events) \
	compat_poll_add(events, fd, req_events)

/*
 * Remove the fd from the pollfd. Memory allocation is done to recreate a new
 * pollfd, data is copied from the old pollfd to the new and, finally, the old
 * one is freed().
 */
extern int compat_poll_del(struct lttng_poll_event *events, int fd);
#define lttng_poll_del(events, fd) \
	compat_poll_del(events, fd)

/*
 * Modify an fd's events in the poll set.
 */
extern int compat_poll_mod(struct lttng_poll_event *events,
		int fd, uint32_t req_events);
#define lttng_poll_mod(events, fd, req_events) \
	compat_poll_mod(events, fd, req_events)

/*
 * Set up the poll set limits variable poll_max_size
 */
extern int compat_poll_set_max_size(void);
#define lttng_poll_set_max_size() \
	compat_poll_set_max_size()

/*
 * No need to reset a pollfd structure for poll(2)
 */
static inline void lttng_poll_reset(struct lttng_poll_event *events)
{}

/*
 * Initialize an already allocated poll event data structure.
 */
static inline void lttng_poll_init(struct lttng_poll_event *events)
{
	memset(events, 0, sizeof(struct lttng_poll_event));
}

/*
 * Clean the events structure of a lttng_poll_event. It's the caller
 * responsability to free the lttng_poll_event memory.
 */
static inline void lttng_poll_clean(struct lttng_poll_event *events)
{
	if (events) {
		__lttng_poll_free((void *) events->wait.events);
		__lttng_poll_free((void *) events->current.events);
	}
}

#endif /* HAVE_EPOLL */

#endif /* _LTT_POLL_H */
Commit	Line	Data
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	26
5eb91c98 DG	27	/*
	28	* Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
	29	*/
	30	static inline void __lttng_poll_free(void *events)
	31	{
0e428499	32	free(events);
5eb91c98 DG	33	}
	34
	35	/*
	36	* epoll(7) implementation.
	37	*/
	38	#ifdef HAVE_EPOLL
	39	#include <sys/epoll.h>
76d7553f	40	#include <stdio.h>
f263b7fd JD	41	#include <features.h>
f263b7fd JD	42	#include <common/compat/fcntl.h>
5eb91c98 DG	43
5eb91c98 DG	44	/* See man epoll(7) for this define path */
990570ed	45	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
5eb91c98 DG	46
	47	enum {
	48	/* Polling variables compatibility for epoll */
	49	LPOLLIN = EPOLLIN,
	50	LPOLLPRI = EPOLLPRI,
	51	LPOLLOUT = EPOLLOUT,
	52	LPOLLRDNORM = EPOLLRDNORM,
	53	LPOLLRDBAND = EPOLLRDBAND,
	54	LPOLLWRNORM = EPOLLWRNORM,
	55	LPOLLWRBAND = EPOLLWRBAND,
	56	LPOLLMSG = EPOLLMSG,
	57	LPOLLERR = EPOLLERR,
	58	LPOLLHUP = EPOLLHUP,
	59	LPOLLNVAL = EPOLLHUP,
	60	LPOLLRDHUP = EPOLLRDHUP,
	61	/* Close on exec feature of epoll */
062fc3d8	62	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
5eb91c98	63	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
f263b7fd JD	64	#else
	65	/*
	66	* EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
	67	* epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
	68	* epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
	69	* directly to fcntl(..) instead.
	70	*/
	71	LTTNG_CLOEXEC = FD_CLOEXEC,
	72	#endif
5eb91c98 DG	73	};
	74
	75	struct compat_epoll_event {
	76	int epfd;
	77	uint32_t nb_fd; /* Current number of fd in events */
d21b0d71 DG	78	uint32_t alloc_size; /* Size of events array */
d21b0d71 DG	79	uint32_t init_size; /* Initial size of events array */
5eb91c98 DG	80	struct epoll_event *events;
	81	};
	82	#define lttng_poll_event compat_epoll_event
	83
beaad64c DG	84	static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
	85	int index, uint32_t nb_fd)
	86	{
	87	assert(events);
	88	assert(index != nb_fd);
	89
	90	if (index == 0 \|\| nb_fd == 0) {
	91	return -1;
	92	} else {
	93	return events->events[index - 1].data.fd;
	94	}
	95	}
	96
5eb91c98 DG	97	/*
	98	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	99	* being the index of the events array.
	100	*/
	101	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
	102	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
	103	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
	104	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
beaad64c DG	105	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
beaad64c DG	106	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
5eb91c98	107
5a12931e	108	/* Create the epoll set. */
5eb91c98 DG	109	extern int compat_epoll_create(struct lttng_poll_event *events,
	110	int size, int flags);
	111	#define lttng_poll_create(events, size, flags) \
65b1b198	112	compat_epoll_create(events, size, flags)
5eb91c98	113
062fc3d8	114	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
f263b7fd JD	115	static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
	116	int flags)
	117	{
	118	return epoll_create1(flags);
	119	}
	120	#else
	121	static inline int compat_glibc_epoll_create(int size, int flags)
	122	{
	123	/*
	124	* epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	125	* epoll_create(..) also means that we lose the possibility to
	126	* directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	127	* fcntl(..).
	128	*/
	129	int efd = epoll_create(size);
	130	assert(fcntl(efd, F_SETFD, flags) != -1);
	131	return efd;
	132	}
	133	#endif
	134
5eb91c98 DG	135	/*
	136	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	137	* data structure (events).
	138	*/
9f32e9bf MD	139	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
9f32e9bf MD	140	bool interruptible);
5eb91c98	141	#define lttng_poll_wait(events, timeout) \
9f32e9bf MD	142	compat_epoll_wait(events, timeout, false)
	143	#define lttng_poll_wait_interruptible(events, timeout) \
	144	compat_epoll_wait(events, timeout, true)
5eb91c98 DG	145
	146	/*
	147	* Add a fd to the epoll set and resize the epoll_event structure if needed.
	148	*/
	149	extern int compat_epoll_add(struct lttng_poll_event *events,
	150	int fd, uint32_t req_events);
	151	#define lttng_poll_add(events, fd, req_events) \
65b1b198	152	compat_epoll_add(events, fd, req_events)
5eb91c98 DG	153
	154	/*
	155	* Remove a fd from the epoll set.
	156	*/
	157	extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
	158	#define lttng_poll_del(events, fd) \
65b1b198	159	compat_epoll_del(events, fd)
5eb91c98	160
f057dfc3 JG	161	/*
	162	* Modify an fd's events in the epoll set.
	163	*/
	164	extern int compat_epoll_mod(struct lttng_poll_event *events,
	165	int fd, uint32_t req_events);
	166	#define lttng_poll_mod(events, fd, req_events) \
2a85be8e	167	compat_epoll_mod(events, fd, req_events)
f057dfc3	168
5eb91c98 DG	169	/*
	170	* Set up the poll set limits variable poll_max_size
	171	*/
dbe23f45	172	extern int compat_epoll_set_max_size(void);
65b1b198 MD	173	#define lttng_poll_set_max_size() \
65b1b198 MD	174	compat_epoll_set_max_size()
5eb91c98 DG	175
	176	/*
	177	* This function memset with zero the structure since it can be reused at each
	178	* round of a main loop. Being in a loop and using a non static number of fds,
	179	* this function must be called to insure coherent events with associted fds.
	180	*/
	181	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	182	{
	183	if (events && events->events) {
	184	memset(events->events, 0,
	185	events->nb_fd * sizeof(struct epoll_event));
	186	}
	187	}
	188
6d737ce4 DG	189	/*
	190	* Initialize an already allocated poll event data structure. For epoll(), the
	191	* epfd is set to -1 to indicate that it's not usable.
	192	*/
	193	static inline void lttng_poll_init(struct lttng_poll_event *events)
	194	{
c5854b1c	195	memset(events, 0, sizeof(struct lttng_poll_event));
6d737ce4 DG	196	/* Set fd to -1 so if clean before created, we don't close 0. */
	197	events->epfd = -1;
	198	}
	199
5eb91c98 DG	200	/*
	201	* Clean the events structure of a lttng_poll_event. It's the caller
	202	* responsability to free the lttng_poll_event memory.
	203	*/
	204	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	205	{
76d7553f MD	206	int ret;
76d7553f MD	207
3cc04881 DG	208	if (!events) {
	209	return;
	210	}
	211
	212	if (events->epfd >= 0) {
76d7553f MD	213	ret = close(events->epfd);
76d7553f MD	214	if (ret) {
6f04ed72	215	PERROR("close");
76d7553f	216	}
5eb91c98	217	}
3cc04881 DG	218
3cc04881 DG	219	__lttng_poll_free((void *) events->events);
5eb91c98 DG	220	}
	221
	222	#else /* HAVE_EPOLL */
	223	/*
	224	* Fallback on poll(2) API
	225	*/
	226
	227	/* Needed for some poll event values */
	228	#ifndef __USE_XOPEN
	229	#define __USE_XOPEN
	230	#endif
	231
	232	/* Needed for some poll event values */
	233	#ifndef __USE_GNU
	234	#define __USE_GNU
	235	#endif
	236
	237	#include <poll.h>
	238	#include <stdint.h>
	239
	240	enum {
	241	/* Polling variables compatibility for poll */
	242	LPOLLIN = POLLIN,
	243	LPOLLPRI = POLLPRI,
	244	LPOLLOUT = POLLOUT,
	245	LPOLLRDNORM = POLLRDNORM,
	246	LPOLLRDBAND = POLLRDBAND,
	247	LPOLLWRNORM = POLLWRNORM,
	248	LPOLLWRBAND = POLLWRBAND,
1268b9d6	249	#if __linux__
5eb91c98	250	LPOLLMSG = POLLMSG,
1268b9d6	251	LPOLLRDHUP = POLLRDHUP,
a97dd6ce	252	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__) \|\| defined(__APPLE__))
1268b9d6 DG	253	LPOLLMSG = 0,
1268b9d6 DG	254	LPOLLRDHUP = 0,
b2c3836f MD	255	#else
b2c3836f MD	256	#error "Please add support for your OS."
1268b9d6	257	#endif /* __linux__ */
5eb91c98 DG	258	LPOLLERR = POLLERR,
5eb91c98 DG	259	LPOLLHUP = POLLHUP \| POLLNVAL,
5eb91c98 DG	260	/* Close on exec feature does not exist for poll(2) */
	261	LTTNG_CLOEXEC = 0xdead,
	262	};
	263
d21b0d71	264	struct compat_poll_event_array {
5eb91c98	265	uint32_t nb_fd; /* Current number of fd in events */
d21b0d71 DG	266	uint32_t alloc_size; /* Size of events array */
	267	/* Initial size of the pollset. We never shrink below that. */
	268	uint32_t init_size;
5eb91c98 DG	269	struct pollfd *events;
5eb91c98 DG	270	};
d21b0d71 DG	271
	272	struct compat_poll_event {
	273	/*
	274	* Modified by the wait action. Updated using current fields if the
	275	* need_update flag is set.
	276	*/
	277	struct compat_poll_event_array wait;
	278	/*
	279	* This is modified by add/del actions being the _current_ flow of
	280	* execution before a poll wait is done.
	281	*/
	282	struct compat_poll_event_array current;
dbe23f45	283
d21b0d71 DG	284	/* Indicate if wait.events need to be updated from current. */
	285	int need_update:1;
	286	};
5eb91c98 DG	287	#define lttng_poll_event compat_poll_event
5eb91c98 DG	288
beaad64c DG	289	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	290	int index, uint32_t nb_fd)
	291	{
	292	assert(events);
	293	assert(index != nb_fd);
	294
	295	if (index == 0 \|\| nb_fd == 0) {
	296	return -1;
	297	} else {
	298	return events->current.events[index - 1].fd;
	299	}
	300	}
	301
5eb91c98 DG	302	/*
	303	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	304	* being the index of the events array.
7e222fa8 YL	305	* LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
7e222fa8 YL	306	* current list for test compatibility purposes.
5eb91c98	307	*/
d21b0d71 DG	308	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
d21b0d71 DG	309	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
7e222fa8	310	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
d21b0d71	311	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
beaad64c DG	312	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
beaad64c DG	313	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
5eb91c98 DG	314
	315	/*
	316	* Create a pollfd structure of size 'size'.
	317	*/
	318	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	319	#define lttng_poll_create(events, size, flags) \
65b1b198	320	compat_poll_create(events, size)
5eb91c98 DG	321
	322	/*
	323	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	324	* structure.
	325	*/
9f32e9bf MD	326	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
9f32e9bf MD	327	bool interruptible);
5eb91c98	328	#define lttng_poll_wait(events, timeout) \
9f32e9bf MD	329	compat_poll_wait(events, timeout, false)
	330	#define lttng_poll_wait_interruptible(events, timeout) \
	331	compat_poll_wait(events, timeout, true)
5eb91c98 DG	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) \
65b1b198	339	compat_poll_add(events, fd, req_events)
5eb91c98 DG	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) \
65b1b198	348	compat_poll_del(events, fd)
5eb91c98	349
f057dfc3	350	/*
b14f53d4	351	* Modify an fd's events in the poll set.
f057dfc3 JG	352	*/
	353	extern int compat_poll_mod(struct lttng_poll_event *events,
	354	int fd, uint32_t req_events);
	355	#define lttng_poll_mod(events, fd, req_events) \
2a85be8e	356	compat_poll_mod(events, fd, req_events)
f057dfc3	357
5eb91c98 DG	358	/*
	359	* Set up the poll set limits variable poll_max_size
	360	*/
dbe23f45	361	extern int compat_poll_set_max_size(void);
65b1b198 MD	362	#define lttng_poll_set_max_size() \
65b1b198 MD	363	compat_poll_set_max_size()
5eb91c98 DG	364
	365	/*
	366	* No need to reset a pollfd structure for poll(2)
	367	*/
	368	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	369	{}
	370
6d737ce4 DG	371	/*
	372	* Initialize an already allocated poll event data structure.
	373	*/
	374	static inline void lttng_poll_init(struct lttng_poll_event *events)
	375	{
	376	memset(events, 0, sizeof(struct lttng_poll_event));
	377	}
	378
5eb91c98 DG	379	/*
	380	* Clean the events structure of a lttng_poll_event. It's the caller
	381	* responsability to free the lttng_poll_event memory.
	382	*/
	383	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	384	{
	385	if (events) {
d21b0d71 DG	386	__lttng_poll_free((void *) events->wait.events);
d21b0d71 DG	387	__lttng_poll_free((void *) events->current.events);
5eb91c98 DG	388	}
	389	}
	390
	391	#endif /* HAVE_EPOLL */
	392
	393	#endif /* _LTT_POLL_H */