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
  34
  35 int rep_poll(struct pollfd *fds, nfds_t nfds, int timeout)
  36 {
  37         fd_set rfds, wfds, efds;
  38         struct timeval tv, *ptv;
  39         int max_fd;
  40         int rc;
  41         nfds_t i;
  42
  43         if (fds == NULL) {
  44                 errno = EFAULT;
  45                 return -1;
  46         }
  47
  48         FD_ZERO(&rfds);
  49         FD_ZERO(&wfds);
  50         FD_ZERO(&efds);
  51
  52         rc = 0;
  53         max_fd = 0;
  54
  55         /* compute fd_sets and find largest descriptor */
  56         for (i = 0; i < nfds; i++) {
  57                 if ((fds[i].fd < 0) || (fds[i].fd >= FD_SETSIZE)) {
  58                         fds[i].revents = POLLNVAL;
  59                         continue;
  60                 }
  61
  62                 if (fds[i].events & (POLLIN | POLLRDNORM)) {
  63                         FD_SET(fds[i].fd, &rfds);
  64                 }
  65                 if (fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
  66                         FD_SET(fds[i].fd, &wfds);
  67                 }
  68                 if (fds[i].events & (POLLPRI | POLLRDBAND)) {
  69                         FD_SET(fds[i].fd, &efds);
  70                 }
  71                 if (fds[i].fd > max_fd &&
  72                     (fds[i].events & (POLLIN | POLLOUT | POLLPRI |
  73                                       POLLRDNORM | POLLRDBAND |
  74                                       POLLWRNORM | POLLWRBAND))) {
  75                         max_fd = fds[i].fd;
  76                 }
  77         }
  78
  79         if (timeout < 0) {
  80                 ptv = NULL;
  81         } else {
  82                 ptv = &tv;
  83                 if (timeout == 0) {
  84                         tv.tv_sec = 0;
  85                         tv.tv_usec = 0;
  86                 } else {
  87                         tv.tv_sec = timeout / 1000;
  88                         tv.tv_usec = (timeout % 1000) * 1000;
  89                 }
  90         }
  91
  92         rc = select(max_fd + 1, &rfds, &wfds, &efds, ptv);
  93         if (rc < 0) {
  94                 return -1;
  95         }
  96
  97         for (rc = 0, i = 0; i < nfds; i++) {
  98                 if ((fds[i].fd < 0) || (fds[i].fd >= FD_SETSIZE)) {
  99                         continue;
 100                 }
 101
 102                 fds[i].revents = 0;
 103
 104                 if (FD_ISSET(fds[i].fd, &rfds)) {
 105                         int err = errno;
 106                         int available = 0;
 107                         int ret;
 108
 109                         /* support for POLLHUP */
 110                         ret = ioctl(fds[i].fd, FIONREAD, &available);
 111                         if ((ret == -1) || (available == 0)) {
 112                                 fds[i].revents |= POLLHUP;
 113                         } else {
 114                                 fds[i].revents |= fds[i].events
 115                                         & (POLLIN | POLLRDNORM);
 116                         }
 117
 118                         errno = err;
 119                 }
 120                 if (FD_ISSET(fds[i].fd, &wfds)) {
 121                         fds[i].revents |= fds[i].events
 122                                 & (POLLOUT | POLLWRNORM | POLLWRBAND);
 123                 }
 124                 if (FD_ISSET(fds[i].fd, &efds)) {
 125                         fds[i].revents |= fds[i].events
 126                                 & (POLLPRI | POLLRDBAND);
 127                 }
 128                 if (fds[i].revents & ~POLLHUP) {
 129                         rc++;
 130                 }
 131         }
 132         return rc;
 133 }