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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/>.
*/
#include <config.h>
#ifdef HAVE_POLL
#include <stdlib.h>
#include <string.h>
#include <sys/poll.h>
#include <stddef.h>
#include "common/fdset_poll.h"
#define OS_FDS_CHUNKSIZE 8 /*!< Number of pollfd structs in a chunk. */
#define OS_FDS_KEEPCHUNKS 32 /*!< Will attempt to free memory when reached. */
struct fdset_t {
struct pollfd *fds;
nfds_t nfds;
size_t reserved;
size_t polled;
size_t begin;
};
fdset_t *fdset_poll_new()
{
fdset_t *set = malloc(sizeof(fdset_t));
if (!set) {
return 0;
}
/* Blank memory. */
memset(set, 0, sizeof(fdset_t));
return set;
}
int fdset_poll_destroy(fdset_t * fdset)
{
if(!fdset) {
return -1;
}
/*! \todo No teardown required I guess. */
/* OK if NULL. */
free(fdset->fds);
free(fdset);
return 0;
}
int fdset_poll_add(fdset_t *fdset, int fd, int events)
{
if (!fdset || fd < 0 || events <= 0) {
return -1;
}
/* Realloc needed. */
if (fdset->nfds == fdset->reserved) {
const size_t chunk = OS_FDS_CHUNKSIZE;
const size_t nsize = sizeof(struct pollfd) * (fdset->reserved + chunk);
struct pollfd *fds_n = malloc(nsize);
if (!fds_n) {
return -1;
}
/* Clear and copy old fdset data. */
memset(fds_n, 0, nsize);
memcpy(fds_n, fdset->fds, fdset->nfds * sizeof(struct pollfd));
free(fdset->fds);
fdset->fds = fds_n;
fdset->reserved += chunk;
}
/* Append. */
int nid = fdset->nfds++;
fdset->fds[nid].fd = fd;
fdset->fds[nid].events = POLLIN; /*! \todo Map events to POLL events. */
return 0;
}
int fdset_poll_remove(fdset_t *fdset, int fd)
{
if (!fdset || fd < 0) {
return -1;
}
/* Find file descriptor. */
unsigned found = 0;
size_t pos = 0;
for (size_t i = 0; i < fdset->nfds; ++i) {
if (fdset->fds[i].fd == fd) {
found = 1;
pos = i;
break;
}
}
/* Check. */
if (!found) {
return -1;
}
/* Overwrite current item. */
size_t remaining = ((fdset->nfds - pos) - 1) * sizeof(struct pollfd);
memmove(fdset->fds + pos, fdset->fds + (pos + 1), remaining);
--fdset->nfds;
/*! \todo Return memory if overallocated (nfds is far lower than reserved). */
/*! \todo Maybe >64 free chunks is excess? */
return 0;
}
int fdset_poll_wait(fdset_t *fdset)
{
if (!fdset || fdset->nfds < 1 || !fdset->fds) {
return -1;
}
/* Initialize pointers. */
fdset->polled = 0;
fdset->begin = 0;
/* Poll for events. */
int ret = poll(fdset->fds, fdset->nfds, -1);
if (ret < 0) {
return -1;
}
/* Set pointers for iterating. */
fdset->polled = ret;
fdset->begin = 0;
return ret;
}
int fdset_poll_begin(fdset_t *fdset, fdset_it_t *it)
{
if (!fdset || !it) {
return -1;
}
/* Find first. */
it->pos = 0;
return fdset_next(fdset, it);
}
int fdset_poll_end(fdset_t *fdset, fdset_it_t *it)
{
if (!fdset || !it || fdset->nfds < 1) {
return -1;
}
/* Check for polled events. */
if (fdset->polled < 1) {
it->fd = -1;
it->pos = 0;
return -1;
}
/* Trace last matching item from the end. */
struct pollfd* pfd = fdset->fds + fdset->nfds - 1;
while (pfd != fdset->fds) {
if (pfd->events & pfd->revents) {
it->fd = pfd->fd;
it->pos = pfd - fdset->fds;
return 0;
}
}
/* No end found, ends on the beginning. */
it->fd = -1;
it->pos = 0;
return -1;
}
int fdset_poll_next(fdset_t *fdset, fdset_it_t *it)
{
if (!fdset || !it || fdset->nfds < 1) {
return -1;
}
/* Find next with matching flags. */
for (; it->pos < fdset->nfds; ++it->pos) {
struct pollfd* pfd = fdset->fds + it->pos;
if (pfd->events & pfd->revents) {
it->fd = pfd->fd;
it->events = pfd->revents; /*! \todo MAP events. */
++it->pos; /* Next will start after current. */
return 0;
}
}
/* No matching event found. */
it->fd = -1;
it->pos = 0;
return -1;
}
const char* fdset_poll_method()
{
return "poll";
}
/* Package APIs. */
struct fdset_backend_t FDSET_POLL = {
.fdset_new = fdset_poll_new,
.fdset_destroy = fdset_poll_destroy,
.fdset_add = fdset_poll_add,
.fdset_remove = fdset_poll_remove,
.fdset_wait = fdset_poll_wait,
.fdset_begin = fdset_poll_begin,
.fdset_end = fdset_poll_end,
.fdset_next = fdset_poll_next,
.fdset_method = fdset_poll_method
};
#endif
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