[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>

/*
 * Maximum number of fd we can monitor.
 *
 * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will
 * be used for the maximum size of the poll set. If this interface is not
 * available, according to the manpage, the max_user_watches value is 1/25 (4%)
 * of the available low memory divided by the registration cost in bytes which
 * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel.
 *
 * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by
 * getrlimit(2).
 */
extern unsigned int poll_max_size;

/*
 * 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>

/* 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 */
	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
};

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. No memory allocation is done here.
 */
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)

/*
 * 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);
#define lttng_poll_wait(events, timeout) \
	compat_epoll_wait(events, timeout)

/*
 * 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)

/*
 * Set up the poll set limits variable poll_max_size
 */
extern void 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));
	}
}

/*
 * 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) {
		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__))
	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 needs to be realloc. */
	int need_realloc:1;
	/* 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.
 */
#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)->wait.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);
#define lttng_poll_wait(events, timeout) \
	compat_poll_wait(events, timeout)

/*
 * 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)

/*
 * Set up the poll set limits variable poll_max_size
 */
extern void 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)
{}

/*
 * 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
	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
	56	/* See man epoll(7) for this define path */
	57	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
	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 */
	80	uint32_t alloc_size; /* Size of events array */
	81	uint32_t init_size; /* Initial size of events array */
	82	struct epoll_event *events;
	83	};
	84	#define lttng_poll_event compat_epoll_event
	85
	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
	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
	107	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	108	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	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) \
	116	compat_epoll_create(events, size, flags)
	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) \
	124	compat_epoll_wait(events, timeout)
	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) \
	132	compat_epoll_add(events, fd, req_events)
	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) \
	139	compat_epoll_del(events, fd)
	140
	141	/*
	142	* Set up the poll set limits variable poll_max_size
	143	*/
	144	extern void compat_epoll_set_max_size(void);
	145	#define lttng_poll_set_max_size() \
	146	compat_epoll_set_max_size()
	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	{
	167	int ret;
	168
	169	if (events) {
	170	ret = close(events->epfd);
	171	if (ret) {
	172	perror("close");
	173	}
	174	__lttng_poll_free((void *) events->events);
	175	}
	176	}
	177
	178	#else /* HAVE_EPOLL */
	179	/*
	180	* Fallback on poll(2) API
	181	*/
	182
	183	/* Needed for some poll event values */
	184	#ifndef __USE_XOPEN
	185	#define __USE_XOPEN
	186	#endif
	187
	188	/* Needed for some poll event values */
	189	#ifndef __USE_GNU
	190	#define __USE_GNU
	191	#endif
	192
	193	#include <poll.h>
	194	#include <stdint.h>
	195
	196	enum {
	197	/* Polling variables compatibility for poll */
	198	LPOLLIN = POLLIN,
	199	LPOLLPRI = POLLPRI,
	200	LPOLLOUT = POLLOUT,
	201	LPOLLRDNORM = POLLRDNORM,
	202	LPOLLRDBAND = POLLRDBAND,
	203	LPOLLWRNORM = POLLWRNORM,
	204	LPOLLWRBAND = POLLWRBAND,
	205	#if __linux__
	206	LPOLLMSG = POLLMSG,
	207	LPOLLRDHUP = POLLRDHUP,
	208	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__))
	209	LPOLLMSG = 0,
	210	LPOLLRDHUP = 0,
	211	#else
	212	#error "Please add support for your OS."
	213	#endif /* __linux__ */
	214	LPOLLERR = POLLERR,
	215	LPOLLHUP = POLLHUP \| POLLNVAL,
	216	/* Close on exec feature does not exist for poll(2) */
	217	LTTNG_CLOEXEC = 0xdead,
	218	};
	219
	220	struct compat_poll_event_array {
	221	uint32_t nb_fd; /* Current number of fd in events */
	222	uint32_t alloc_size; /* Size of events array */
	223	/* Initial size of the pollset. We never shrink below that. */
	224	uint32_t init_size;
	225	struct pollfd *events;
	226	};
	227
	228	struct compat_poll_event {
	229	/*
	230	* Modified by the wait action. Updated using current fields if the
	231	* need_update flag is set.
	232	*/
	233	struct compat_poll_event_array wait;
	234	/*
	235	* This is modified by add/del actions being the _current_ flow of
	236	* execution before a poll wait is done.
	237	*/
	238	struct compat_poll_event_array current;
	239	/* Indicate if wait.events needs to be realloc. */
	240	int need_realloc:1;
	241	/* Indicate if wait.events need to be updated from current. */
	242	int need_update:1;
	243	};
	244	#define lttng_poll_event compat_poll_event
	245
	246	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	247	int index, uint32_t nb_fd)
	248	{
	249	assert(events);
	250	assert(index != nb_fd);
	251
	252	if (index == 0 \|\| nb_fd == 0) {
	253	return -1;
	254	} else {
	255	return events->current.events[index - 1].fd;
	256	}
	257	}
	258
	259	/*
	260	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	261	* being the index of the events array.
	262	*/
	263	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
	264	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
	265	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd
	266	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
	267	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	268	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	269
	270	/*
	271	* Create a pollfd structure of size 'size'.
	272	*/
	273	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	274	#define lttng_poll_create(events, size, flags) \
	275	compat_poll_create(events, size)
	276
	277	/*
	278	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	279	* structure.
	280	*/
	281	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout);
	282	#define lttng_poll_wait(events, timeout) \
	283	compat_poll_wait(events, timeout)
	284
	285	/*
	286	* Add the fd to the pollfd structure. Resize if needed.
	287	*/
	288	extern int compat_poll_add(struct lttng_poll_event *events,
	289	int fd, uint32_t req_events);
	290	#define lttng_poll_add(events, fd, req_events) \
	291	compat_poll_add(events, fd, req_events)
	292
	293	/*
	294	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	295	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	296	* one is freed().
	297	*/
	298	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	299	#define lttng_poll_del(events, fd) \
	300	compat_poll_del(events, fd)
	301
	302	/*
	303	* Set up the poll set limits variable poll_max_size
	304	*/
	305	extern void compat_poll_set_max_size(void);
	306	#define lttng_poll_set_max_size() \
	307	compat_poll_set_max_size()
	308
	309	/*
	310	* No need to reset a pollfd structure for poll(2)
	311	*/
	312	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	313	{}
	314
	315	/*
	316	* Clean the events structure of a lttng_poll_event. It's the caller
	317	* responsability to free the lttng_poll_event memory.
	318	*/
	319	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	320	{
	321	if (events) {
	322	__lttng_poll_free((void *) events->wait.events);
	323	__lttng_poll_free((void *) events->current.events);
	324	}
	325	}
	326
	327	#endif /* HAVE_EPOLL */
	328
	329	#endif /* _LTT_POLL_H */