kernel/core/fd.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2008  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *  Copyright (C) 2009  Martin 'povik' Poviser (martin.povik@gmail.com)
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20
  21 #include <build.h>
  22 #include <system.h>
  23 #include <string.h>
  24 #include <fd.h>
  25 #include <errno.h>
  26
  27 fd_t fd_list;
  28
  29 fd_t *fd_get (int id)
  30 {
  31         fd_t *fd;
  32         for (fd = fd_list.next; fd != &fd_list; fd = fd->next) {
  33                 if (fd->id == (unsigned) id)
  34                         return fd;
  35         }
  36
  37         return 0;
  38 }
  39
  40 fd_t *fd_create (int flags)
  41 {
  42         int id = 0;
  43         fd_t *fd = kmalloc (sizeof (fd_t));
  44
  45         if (!fd) {
  46                 errno_set (ENOMEM);
  47                 return 0;
  48         }
  49
  50         while (id >= 0) {
  51                 id ++;
  52                 if (!fd_get (id))
  53                         break;
  54         }
  55
  56         if (id < 0) {
  57                 errno_set (ENFILE);
  58                 return 0;
  59         }
  60
  61         fd->id = id;
  62         fd->flags = flags;
  63
  64         fd->e = 1;
  65         fd->s = (char *) 0;
  66         fd->p = 0;
  67         fd->path = 0;
  68         fd->proc = 0;
  69
  70         /* add into list */
  71         fd->next = &fd_list;
  72         fd->prev = fd_list.prev;
  73         fd->prev->next = fd;
  74         fd->next->prev = fd;
  75
  76         return fd;
  77 }
  78
  79 int fd_delete (fd_t *fd)
  80 {
  81         if (!fd)
  82                 return 0;
  83
  84         if (fd->path)
  85                 kfree (fd->path);
  86
  87         fd->s = 0;
  88         fd->e = 0;
  89         fd->flags = 0;
  90         fd->id = 0;
  91         fd->p = 0;
  92         fd->dev = 0;
  93         fd->proc = 0;
  94
  95         /* delete old file descriptor from fd_list */
  96         fd->next->prev = fd->prev;
  97         fd->prev->next = fd->next;
  98
  99         kfree (fd);
 100
 101         return 1;
 102 }
 103
 104 unsigned int init_fd ()
 105 {
 106         fd_list.next = &fd_list;
 107         fd_list.prev = &fd_list;
 108
 109         /* HACK: first we need create file descriptor 0 and 1 for stdout and stdin */
 110         stdin = fd_create (0);
 111         stdout = fd_create (0);
 112
 113         return 1;
 114 }