libc/sys/select.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include <sys/select.h>
  21 #include <sys/time.h>
  22 #include <errno.h>
  23 #include <_libc.h>
  24
  25 void _fd_clr (int fd, fd_set *set)
  26 {
  27         if (!set || fd < 0)
  28                 return;
  29
  30         unsigned i;
  31
  32         for (i = 0; i < set->count; i ++)
  33                 if (set->fd[i] == fd) {
  34                         set->fd[i] = -1;
  35
  36                         if (set->count == i+1)
  37                                 set->count --;
  38                         break;
  39                 }
  40 }
  41
  42 int _fd_isset (int fd, fd_set *set)
  43 {
  44         if (!set || fd < 0)
  45                 return 0;
  46
  47         unsigned i;
  48
  49         for (i = 0; i < set->count; i ++)
  50                 if (set->fd[i] == fd)
  51                         return 1;
  52
  53         return 0;
  54 }
  55
  56 void _fd_set (int fd, fd_set *set)
  57 {
  58         if (!set || fd < 0)
  59                 return;
  60
  61         unsigned i;
  62         unsigned y = 0;
  63
  64         /* try to find free entry in actual list */
  65         for (i = 0; i < set->count; i ++)
  66                 if (set->fd[i] == -1) {
  67                         set->fd[i] = fd;
  68                         y ++;
  69                         break;
  70                 }
  71
  72         /* add new entry into list */
  73         if (!y) {
  74                 if (set->count < FD_SETSIZE)
  75                         set->fd[set->count ++] = fd;
  76         }
  77 }
  78
  79 void _fd_zero (fd_set *set)
  80 {
  81         if (!set)
  82                 return;
  83
  84         set->count = 0;
  85 }
  86
  87 int select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
  88 {
  89         struct select_t {
  90                 int nfds;
  91                 fd_set *readfds;
  92                 fd_set *writefds;
  93                 fd_set *exceptfds;
  94                 struct timeval *timeout;
  95         };
  96
  97         struct select_t s;
  98         s.nfds = nfds;
  99         s.readfds = readfds;
 100         s.writefds = writefds;
 101         s.exceptfds = exceptfds;
 102         s.timeout = timeout;
 103
 104         asm volatile (
 105                 "movl $64, %%eax;"
 106                 "movl %0, %%ebx;"
 107                 "int $0x80;":: "b" (&s) : "%eax", "memory");
 108
 109         errno_update ();
 110
 111         /* get return value */
 112         return (int) *SYSV_SELECT;
 113 }