patch for syslog
[p5sagit/p5-mst-13.2.git] / ext / IO / poll.c
CommitLineData
cf7fe8a2 1/*
2 * poll.c
3 *
4 * Copyright (c) 1997-8 Graham Barr <gbarr@pobox.com>. All rights reserved.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the same terms as Perl itself.
7 *
b38f6a39 8 * For systems that do not have the poll() system call (for example Linux
9 * kernels < v2.1.23) try to emulate it as closely as possible using select()
cf7fe8a2 10 *
11 */
12
13#include "EXTERN.h"
14#include "perl.h"
15#include "poll.h"
16#ifdef I_SYS_TIME
17# include <sys/time.h>
18#endif
19#ifdef I_TIME
20# include <time.h>
21#endif
22#include <sys/types.h>
23#if defined(HAS_SOCKET) && !defined(VMS) /* VMS handles sockets via vmsish.h */
24# include <sys/socket.h>
25#endif
26#include <sys/stat.h>
27#include <errno.h>
28
465a6d9a 29#ifdef HAS_SELECT
30#ifdef I_SYS_SELECT
31#include <sys/select.h>
32#endif
33#endif
34
cf7fe8a2 35#ifdef EMULATE_POLL_WITH_SELECT
36
37# define POLL_CAN_READ (POLLIN | POLLRDNORM )
38# define POLL_CAN_WRITE (POLLOUT | POLLWRNORM | POLLWRBAND )
39# define POLL_HAS_EXCP (POLLRDBAND | POLLPRI )
40
41# define POLL_EVENTS_MASK (POLL_CAN_READ | POLL_CAN_WRITE | POLL_HAS_EXCP)
42
43int
35ef4773 44poll(struct pollfd *fds, unsigned long nfds, int timeout)
cf7fe8a2 45{
46 int i,err;
47 fd_set rfd,wfd,efd,ifd;
48 struct timeval timebuf;
49 struct timeval *tbuf = (struct timeval *)0;
50 int n = 0;
51 int count;
52
53 FD_ZERO(&ifd);
54
55again:
56
57 FD_ZERO(&rfd);
58 FD_ZERO(&wfd);
59 FD_ZERO(&efd);
60
61 for(i = 0 ; i < nfds ; i++) {
62 int events = fds[i].events;
63 int fd = fds[i].fd;
64
65 fds[i].revents = 0;
66
67 if(fd < 0 || FD_ISSET(fd, &ifd))
68 continue;
69
70 if(fd > n)
71 n = fd;
72
73 if(events & POLL_CAN_READ)
74 FD_SET(fd, &rfd);
75
76 if(events & POLL_CAN_WRITE)
77 FD_SET(fd, &wfd);
78
79 if(events & POLL_HAS_EXCP)
80 FD_SET(fd, &efd);
81 }
82
83 if(timeout >= 0) {
84 timebuf.tv_sec = timeout / 1000;
85 timebuf.tv_usec = (timeout % 1000) * 1000;
86 tbuf = &timebuf;
87 }
88
89 err = select(n+1,&rfd,&wfd,&efd,tbuf);
90
91 if(err < 0) {
92#ifdef HAS_FSTAT
93 if(errno == EBADF) {
94 for(i = 0 ; i < nfds ; i++) {
95 struct stat buf;
96 if((fstat(fds[i].fd,&buf) < 0) && (errno == EBADF)) {
97 FD_SET(fds[i].fd, &ifd);
98 goto again;
99 }
100 }
101 }
102#endif /* HAS_FSTAT */
103 return err;
104 }
105
106 count = 0;
107
108 for(i = 0 ; i < nfds ; i++) {
109 int revents = (fds[i].events & POLL_EVENTS_MASK);
110 int fd = fds[i].fd;
111
112 if(fd < 0)
113 continue;
114
115 if(FD_ISSET(fd, &ifd))
116 revents = POLLNVAL;
117 else {
118 if(!FD_ISSET(fd, &rfd))
119 revents &= ~POLL_CAN_READ;
120
121 if(!FD_ISSET(fd, &wfd))
122 revents &= ~POLL_CAN_WRITE;
123
124 if(!FD_ISSET(fd, &efd))
125 revents &= ~POLL_HAS_EXCP;
126 }
127
128 if((fds[i].revents = revents) != 0)
129 count++;
130 }
131
132 return count;
133}
134
135#endif /* EMULATE_POLL_WITH_SELECT */