1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
#include <poll.h>
#include "taia.h"
#include "select.h"
#include "iopause.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;
}
|
