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 #ifdef I_TIME
22 # include <time.h>
23 #endif
24 #include <sys/types.h>
25 #if defined(HAS_SOCKET) && !defined(VMS) && !defined(ultrix) /* VMS handles sockets via vmsish.h, ULTRIX dies of socket struct redefinitions */
26 # include <sys/socket.h>
27 #endif
28 #include <sys/stat.h>
29 #include <errno.h>
30
31 #ifdef HAS_SELECT
32 #ifdef I_SYS_SELECT
33 #include <sys/select.h>
34 #endif
35 #endif
36
37 #ifdef EMULATE_POLL_WITH_SELECT
38
39 # define POLL_CAN_READ (POLLIN | POLLRDNORM )
40 # define POLL_CAN_WRITE (POLLOUT | POLLWRNORM | POLLWRBAND )
41 # define POLL_HAS_EXCP (POLLRDBAND | POLLPRI )
42
43 # define POLL_EVENTS_MASK (POLL_CAN_READ | POLL_CAN_WRITE | POLL_HAS_EXCP)
44
45 int
poll(struct pollfd * fds,unsigned long nfds,int timeout)46 poll(struct pollfd *fds, unsigned long nfds, int timeout)
47 {
48 int i,err;
49 fd_set rfd,wfd,efd,ifd;
50 struct timeval timebuf;
51 struct timeval *tbuf = (struct timeval *)0;
52 int n = 0;
53 int count;
54
55 FD_ZERO(&ifd);
56
57 again:
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__)
144 static int dummy;
145 #endif
146
147