Mike Lockwood | 1305e95 | 2011-12-07 08:17:59 -0800 | [diff] [blame] | 1 | /* $Id: bsd-poll.c,v 1.4 2008/08/29 21:32:38 dtucker Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au). |
| 5 | * |
| 6 | * Permission to use, copy, modify, and distribute this software for any |
| 7 | * purpose with or without fee is hereby granted, provided that the above |
| 8 | * copyright notice and this permission notice appear in all copies. |
| 9 | * |
| 10 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 11 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 12 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| 13 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 14 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| 15 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| 16 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| 17 | */ |
| 18 | |
| 19 | #include "includes.h" |
| 20 | #if !defined(HAVE_POLL) |
| 21 | |
| 22 | #ifdef HAVE_SYS_SELECT_H |
| 23 | # include <sys/select.h> |
| 24 | #endif |
| 25 | |
| 26 | #include <stdlib.h> |
| 27 | #include <errno.h> |
| 28 | #include "bsd-poll.h" |
| 29 | |
| 30 | /* |
| 31 | * A minimal implementation of poll(2), built on top of select(2). |
| 32 | * |
| 33 | * Only supports POLLIN and POLLOUT flags in pfd.events, and POLLIN, POLLOUT |
| 34 | * and POLLERR flags in revents. |
| 35 | * |
| 36 | * Supports pfd.fd = -1 meaning "unused" although it's not standard. |
| 37 | */ |
| 38 | |
| 39 | int |
| 40 | poll(struct pollfd *fds, nfds_t nfds, int timeout) |
| 41 | { |
| 42 | nfds_t i; |
| 43 | int saved_errno, ret, fd, maxfd = 0; |
| 44 | fd_set *readfds = NULL, *writefds = NULL, *exceptfds = NULL; |
| 45 | size_t nmemb; |
| 46 | struct timeval tv, *tvp = NULL; |
| 47 | |
| 48 | for (i = 0; i < nfds; i++) { |
| 49 | fd = fds[i].fd; |
| 50 | if (fd >= FD_SETSIZE) { |
| 51 | errno = EINVAL; |
| 52 | return -1; |
| 53 | } |
| 54 | maxfd = MAX(maxfd, fd); |
| 55 | } |
| 56 | |
| 57 | nmemb = howmany(maxfd + 1 , NFDBITS); |
| 58 | if ((readfds = calloc(nmemb, sizeof(fd_mask))) == NULL || |
| 59 | (writefds = calloc(nmemb, sizeof(fd_mask))) == NULL || |
| 60 | (exceptfds = calloc(nmemb, sizeof(fd_mask))) == NULL) { |
| 61 | saved_errno = ENOMEM; |
| 62 | ret = -1; |
| 63 | goto out; |
| 64 | } |
| 65 | |
| 66 | /* populate event bit vectors for the events we're interested in */ |
| 67 | for (i = 0; i < nfds; i++) { |
| 68 | fd = fds[i].fd; |
| 69 | if (fd == -1) |
| 70 | continue; |
| 71 | if (fds[i].events & POLLIN) { |
| 72 | FD_SET(fd, readfds); |
| 73 | FD_SET(fd, exceptfds); |
| 74 | } |
| 75 | if (fds[i].events & POLLOUT) { |
| 76 | FD_SET(fd, writefds); |
| 77 | FD_SET(fd, exceptfds); |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | /* poll timeout is msec, select is timeval (sec + usec) */ |
| 82 | if (timeout >= 0) { |
| 83 | tv.tv_sec = timeout / 1000; |
| 84 | tv.tv_usec = (timeout % 1000) * 1000; |
| 85 | tvp = &tv; |
| 86 | } |
| 87 | |
| 88 | ret = select(maxfd + 1, readfds, writefds, exceptfds, tvp); |
| 89 | saved_errno = errno; |
| 90 | |
| 91 | /* scan through select results and set poll() flags */ |
| 92 | for (i = 0; i < nfds; i++) { |
| 93 | fd = fds[i].fd; |
| 94 | fds[i].revents = 0; |
| 95 | if (fd == -1) |
| 96 | continue; |
| 97 | if (FD_ISSET(fd, readfds)) { |
| 98 | fds[i].revents |= POLLIN; |
| 99 | } |
| 100 | if (FD_ISSET(fd, writefds)) { |
| 101 | fds[i].revents |= POLLOUT; |
| 102 | } |
| 103 | if (FD_ISSET(fd, exceptfds)) { |
| 104 | fds[i].revents |= POLLERR; |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | out: |
| 109 | if (readfds != NULL) |
| 110 | free(readfds); |
| 111 | if (writefds != NULL) |
| 112 | free(writefds); |
| 113 | if (exceptfds != NULL) |
| 114 | free(exceptfds); |
| 115 | if (ret == -1) |
| 116 | errno = saved_errno; |
| 117 | return ret; |
| 118 | } |
| 119 | #endif |