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#include "iopause.h"
#include <poll.h>
#include "select.h"
#include "taia.h"
/**
@file iopause.c
@author djb
@source qmail
@brief stateful reading from net
@return > 0 if successful
*/
int iopause(iopause_fd *x, unsigned int len, struct taia *deadline, struct taia *stamp)
{
struct taia t;
int millisecs;
double d;
int i, r;
if (taia_less(deadline, stamp))
millisecs = 0;
else {
t = *stamp;
taia_sub(&t, deadline, &t);
d = taia_approx(&t);
if (d > 1000.0) d = 1000.0;
millisecs = d * 1000.0 + 20.0;
if (millisecs < 0) millisecs = 20.0;
}
for (i = 0; i < len; ++i) x[i].revents = 0;
#ifdef IOPAUSE_POLL
r = poll(x, len, millisecs);
/* XXX: some kernels apparently need x[0] even if len is 0 */
/* XXX: how to handle EAGAIN? are kernels really this dumb? */
/* XXX: how to handle EINVAL? when exactly can this happen? */
#else
struct timeval tv;
fd_set rfds;
fd_set wfds;
int nfds;
int fd;
FD_ZERO(&rfds);
FD_ZERO(&wfds);
nfds = 1;
for (i = 0; i < len; ++i) {
fd = x[i].fd;
if (fd < 0) continue;
if (fd >= 8 * sizeof(fd_set)) continue; /*XXX*/
if (fd >= nfds) nfds = fd + 1;
if (x[i].events & IOPAUSE_READ) FD_SET(fd, &rfds);
if (x[i].events & IOPAUSE_WRITE) FD_SET(fd, &wfds);
}
tv.tv_sec = millisecs / 1000;
tv.tv_usec = 1000 * (millisecs % 1000);
r = select(nfds, &rfds, &wfds, (fd_set *)0, &tv);
if (r <= 0) return r;
/* XXX: for EBADF, could seek out and destroy the bad descriptor */
for (i = 0; i < len; ++i) {
fd = x[i].fd;
if (fd < 0) continue;
if (fd >= 8 * sizeof(fd_set)) continue; /*XXX*/
if (x[i].events & IOPAUSE_READ)
if (FD_ISSET(fd, &rfds)) x[i].revents |= IOPAUSE_READ;
if (x[i].events & IOPAUSE_WRITE)
if (FD_ISSET(fd, &wfds)) x[i].revents |= IOPAUSE_WRITE;
}
#endif
return r;
}
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