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/* Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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, see <http://www.gnu.org/licenses/>.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE /* Required for RTLD_DEFAULT. */
#endif
#include <dlfcn.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <config.h>
#include "common/fdset.h"
/* Workarounds for clock_gettime() not available on some platforms. */
#ifdef HAVE_CLOCK_GETTIME
#define time_now(x) clock_gettime(CLOCK_MONOTONIC, (x))
typedef struct timespec timev_t;
#elif HAVE_GETTIMEOFDAY
#include <sys/time.h>
#define time_now(x) gettimeofday((x), NULL)
typedef struct timeval timev_t;
#else
#error Neither clock_gettime() nor gettimeofday() found. At least one is required.
#endif
struct fdset_backend_t _fdset_backend = {
};
/*! \brief Set backend implementation. */
static void fdset_set_backend(struct fdset_backend_t *backend) {
memcpy(&_fdset_backend, backend, sizeof(struct fdset_backend_t));
}
/* Linux epoll API. */
#ifdef HAVE_EPOLL_WAIT
#include "common/fdset_epoll.h"
#endif /* HAVE_EPOLL_WAIT */
/* BSD kqueue API */
#ifdef HAVE_KQUEUE
#include "common/fdset_kqueue.h"
#endif /* HAVE_KQUEUE */
/* POSIX poll API */
#ifdef HAVE_POLL
#include "common/fdset_poll.h"
#endif /* HAVE_POLL */
/*! \brief Bootstrap polling subsystem (it is called automatically). */
void __attribute__ ((constructor)) fdset_init()
{
/* Preference: epoll */
#ifdef HAVE_EPOLL_WAIT
if (dlsym(RTLD_DEFAULT, "epoll_wait") != 0) {
fdset_set_backend(&FDSET_EPOLL);
return;
}
#endif
/* Preference: kqueue */
#ifdef HAVE_KQUEUE
if (dlsym(RTLD_DEFAULT, "kqueue") != 0) {
fdset_set_backend(&FDSET_KQUEUE);
return;
}
#endif
/* Fallback: poll */
#ifdef HAVE_POLL
if (dlsym(RTLD_DEFAULT, "poll") != 0) {
fdset_set_backend(&FDSET_POLL);
return;
}
#endif
/* This shouldn't happen. */
fprintf(stderr, "fdset: fatal error - no valid fdset backend found\n");
return;
}
/*!
* \brief Compare file descriptors.
*
* \param a File descriptor.
* \param b File descriptor.
*
* \retval -1 if a < b
* \retval 0 if a == b
* \retval 1 if a > b
*/
static inline int fdset_compare(void *a, void *b)
{
if (a > b) return 1;
if (a < b) return -1;
return 0;
}
fdset_t *fdset_new() {
fdset_t* set = _fdset_backend.fdset_new();
fdset_base_t *base = (fdset_base_t*)set;
if (base != NULL) {
/* Create atimes list. */
base->atimes = skip_create_list(fdset_compare);
if (base->atimes == NULL) {
fdset_destroy(set);
set = NULL;
}
}
return set;
}
int fdset_destroy(fdset_t* fdset) {
fdset_base_t *base = (fdset_base_t*)fdset;
if (base != NULL && base->atimes != NULL) {
skip_destroy_list(&base->atimes, NULL, free);
}
return _fdset_backend.fdset_destroy(fdset);
}
int fdset_remove(fdset_t *fdset, int fd) {
fdset_base_t *base = (fdset_base_t*)fdset;
if (base != NULL && base->atimes != NULL) {
skip_remove(base->atimes, (void*)((size_t)fd), NULL, free);
}
return _fdset_backend.fdset_remove(fdset, fd);
}
int fdset_set_watchdog(fdset_t* fdset, int fd, int interval)
{
fdset_base_t *base = (fdset_base_t*)fdset;
if (base == NULL || base->atimes == NULL) {
return -1;
}
/* Lift watchdog if interval is negative. */
if (interval < 0) {
skip_remove(base->atimes, (void*)((size_t)fd), NULL, free);
return 0;
}
/* Find if exists. */
timev_t *ts = NULL;
ts = (timev_t*)skip_find(base->atimes, (void*)((size_t)fd));
if (ts == NULL) {
ts = malloc(sizeof(timev_t));
if (ts == NULL) {
return -1;
}
skip_insert(base->atimes, (void*)((size_t)fd), (void*)ts, NULL);
}
/* Update clock. */
if (time_now(ts) < 0) {
return -1;
}
ts->tv_sec += interval; /* Only seconds precision. */
return 0;
}
int fdset_sweep(fdset_t* fdset, void(*cb)(fdset_t*, int, void*), void *data)
{
fdset_base_t *base = (fdset_base_t*)fdset;
if (base == NULL || base->atimes == NULL) {
return -1;
}
/* Get time threshold. */
timev_t now;
if (time_now(&now) < 0) {
return -1;
}
/* Inspect all nodes. */
int sweeped = 0;
const skip_node_t *n = skip_first(base->atimes);
while (n != NULL) {
const skip_node_t* pnext = skip_next(n);
/* Evaluate */
timev_t *ts = (timev_t*)n->value;
if (ts->tv_sec <= now.tv_sec) {
cb(fdset, (int)(((ssize_t)n->key)), data);
++sweeped;
}
n = pnext;
}
return sweeped;
}
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