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 *
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()
10 *
11 */
12
13#include "EXTERN.h"
14#include "perl.h"
15#include "XSUB.h"
16
17#include "poll.h"
18#ifdef I_SYS_TIME
19# include <sys/time.h>
20#endif
21#include <time.h>
22#include <sys/types.h>
23#if defined(HAS_SOCKET) && !defined(VMS) && !defined(ultrix) /* VMS handles sockets via vmsish.h, ULTRIX dies of socket struct redefinitions */
24#  include <sys/socket.h>
25#endif
26#include <sys/stat.h>
27#include <errno.h>
28
29#ifdef HAS_SELECT
30#ifdef I_SYS_SELECT
31#include <sys/select.h>
32#endif
33#endif
34
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
44poll(struct pollfd *fds, unsigned long nfds, int timeout)
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
55#ifdef HAS_FSTAT
56again:
57#endif
58
59    FD_ZERO(&rfd);
60    FD_ZERO(&wfd);
61    FD_ZERO(&efd);
62
63    for(i = 0 ; i < (int)nfds ; i++) {
64        int events = fds[i].events;
65        int fd = fds[i].fd;
66
67        fds[i].revents = 0;
68
69        if(fd < 0 || FD_ISSET(fd, &ifd))
70            continue;
71
72        if(fd > n)
73            n = fd;
74
75        if(events & POLL_CAN_READ)
76            FD_SET(fd, &rfd);
77
78        if(events & POLL_CAN_WRITE)
79            FD_SET(fd, &wfd);
80
81        if(events & POLL_HAS_EXCP)
82            FD_SET(fd, &efd);
83    }
84
85    if(timeout >= 0) {
86        timebuf.tv_sec = timeout / 1000;
87        timebuf.tv_usec = (timeout % 1000) * 1000;
88        tbuf = &timebuf;
89    }
90
91    err = select(n+1,&rfd,&wfd,&efd,tbuf);
92
93    if(err < 0) {
94#ifdef HAS_FSTAT
95        if(errno == EBADF) {
96            for(i = 0 ; i < nfds ; i++) {
97                struct stat buf;
98                if((fstat(fds[i].fd,&buf) < 0) && (errno == EBADF)) {
99                    FD_SET(fds[i].fd, &ifd);
100                    goto again;
101                }
102            }
103        }
104#endif /* HAS_FSTAT */
105        return err;
106    }
107
108    count = 0;
109
110    for(i = 0 ; i < (int)nfds ; i++) {
111        int revents = (fds[i].events & POLL_EVENTS_MASK);
112        int fd = fds[i].fd;
113
114        if(fd < 0)
115            continue;
116
117        if(FD_ISSET(fd, &ifd))
118            revents = POLLNVAL;
119        else {
120            if(!FD_ISSET(fd, &rfd))
121                revents &= ~POLL_CAN_READ;
122
123            if(!FD_ISSET(fd, &wfd))
124                revents &= ~POLL_CAN_WRITE;
125
126            if(!FD_ISSET(fd, &efd))
127                revents &= ~POLL_HAS_EXCP;
128        }
129
130        if((fds[i].revents = revents) != 0)
131            count++;
132    }
133
134    return count;
135}
136
137#endif /* EMULATE_POLL_WITH_SELECT */
138
139/* gcc for SunOS 4 produces code from an empty (code/symbolwise)
140 * source code file that makes the SunOS 4.x /usr/bin/ld fail with
141 * ld: poll.o: premature EOF
142 * To avoid this, have at least something in here.  */
143#if defined(__sun) && !defined(__SVR4) && defined(__GNUC__)
144static int dummy;
145#endif
146
147