com32/lib/sys/read.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 /*
  29  * read.c
  30  *
  31  * Reading from a file descriptor
  32  */
  33
  34 #include <errno.h>
  35 #include <string.h>
  36 #include <com32.h>
  37 #include <minmax.h>
  38 #include <klibc/compiler.h>
  39 #include "file.h"
  40
  41 ssize_t read(int fd, void *buf, size_t count)
  42 {
  43     struct file_info *fp = &__file_info[fd];
  44
  45     if (fd >= NFILES || !fp->iop) {
  46         errno = EBADF;
  47         return -1;
  48     }
  49
  50     return fp->iop->read(fp, buf, count);
  51 }