lib/replace/poll.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    poll.c - poll wrapper
   4
   5    This file is based on code from libssh (LGPLv2.1+ at the time it
   6    was downloaded), thus the following copyrights:
   7
   8    Copyright (c) 2009-2010 by Andreas Schneider <mail@cynapses.org>
   9    Copyright (c) 2003-2009 by Aris Adamantiadis
  10    Copyright (c) 2009 Aleksandar Kanchev
  11    Copyright (C) Volker Lendecke 2011
  12
  13      ** NOTE! The following LGPL license applies to the replace
  14      ** library. This does NOT imply that all of Samba is released
  15      ** under the LGPL
  16
  17    This library is free software; you can redistribute it and/or
  18    modify it under the terms of the GNU Lesser General Public
  19    License as published by the Free Software Foundation; either
  20    version 3 of the License, or (at your option) any later version.
  21
  22    This library is distributed in the hope that it will be useful,
  23    but WITHOUT ANY WARRANTY; without even the implied warranty of
  24    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25    Lesser General Public License for more details.
  26
  27    You should have received a copy of the GNU Lesser General Public
  28    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  29  */
  30
  31 #include "replace.h"
  32 #include "system/select.h"
  33 #ifdef HAVE_SYS_TIME_H
  34 #include <sys/time.h>
  35 #endif
  36 #ifdef HAVE_SYS_IOCTL_H
  37 #include <sys/ioctl.h>
  38 #endif
  39
  40
  41 int rep_poll(struct pollfd *fds, nfds_t nfds, int timeout)
  42 {
  43         fd_set rfds, wfds, efds;
  44         struct timeval tv, *ptv;
  45         int max_fd;
  46         int rc;
  47         nfds_t i;
  48
  49         if ((fds == NULL) && (nfds != 0)) {
  50                 errno = EFAULT;
  51                 return -1;
  52         }
  53
  54         FD_ZERO(&rfds);
  55         FD_ZERO(&wfds);
  56         FD_ZERO(&efds);
  57
  58         rc = 0;
  59         max_fd = 0;
  60
  61         /* compute fd_sets and find largest descriptor */
  62         for (i = 0; i < nfds; i++) {
  63                 if ((fds[i].fd < 0) || (fds[i].fd >= FD_SETSIZE)) {
  64                         fds[i].revents = POLLNVAL;
  65                         continue;
  66                 }
  67
  68                 if (fds[i].events & (POLLIN | POLLRDNORM)) {
  69                         FD_SET(fds[i].fd, &rfds);
  70                 }
  71                 if (fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
  72                         FD_SET(fds[i].fd, &wfds);
  73                 }
  74                 if (fds[i].events & (POLLPRI | POLLRDBAND)) {
  75                         FD_SET(fds[i].fd, &efds);
  76                 }
  77                 if (fds[i].fd > max_fd &&
  78                     (fds[i].events & (POLLIN | POLLOUT | POLLPRI |
  79                                       POLLRDNORM | POLLRDBAND |
  80                                       POLLWRNORM | POLLWRBAND))) {
  81                         max_fd = fds[i].fd;
  82                 }
  83         }
  84
  85         if (timeout < 0) {
  86                 ptv = NULL;
  87         } else {
  88                 ptv = &tv;
  89                 if (timeout == 0) {
  90                         tv.tv_sec = 0;
  91                         tv.tv_usec = 0;
  92                 } else {
  93                         tv.tv_sec = timeout / 1000;
  94                         tv.tv_usec = (timeout % 1000) * 1000;
  95                 }
  96         }
  97
  98         rc = select(max_fd + 1, &rfds, &wfds, &efds, ptv);
  99         if (rc < 0) {
 100                 return -1;
 101         }
 102
 103         for (rc = 0, i = 0; i < nfds; i++) {
 104                 if ((fds[i].fd < 0) || (fds[i].fd >= FD_SETSIZE)) {
 105                         continue;
 106                 }
 107
 108                 fds[i].revents = 0;
 109
 110                 if (FD_ISSET(fds[i].fd, &rfds)) {
 111                         int err = errno;
 112                         int available = 0;
 113                         int ret;
 114
 115                         /* support for POLLHUP */
 116                         ret = ioctl(fds[i].fd, FIONREAD, &available);
 117                         if ((ret == -1) || (available == 0)) {
 118                                 fds[i].revents |= POLLHUP;
 119                         } else {
 120                                 fds[i].revents |= fds[i].events
 121                                         & (POLLIN | POLLRDNORM);
 122                         }
 123
 124                         errno = err;
 125                 }
 126                 if (FD_ISSET(fds[i].fd, &wfds)) {
 127                         fds[i].revents |= fds[i].events
 128                                 & (POLLOUT | POLLWRNORM | POLLWRBAND);
 129                 }
 130                 if (FD_ISSET(fds[i].fd, &efds)) {
 131                         fds[i].revents |= fds[i].events
 132                                 & (POLLPRI | POLLRDBAND);
 133                 }
 134                 if (fds[i].revents & ~POLLHUP) {
 135                         rc++;
 136                 }
 137         }
 138         return rc;
 139 }