workbench/network/stacks/AROSTCP/netlib/_lseek.c

   1 /* $Id$
   2  *
   3  *      _lseek.c - lseek() which knows sockets (SAS/C)
   4  *
   5  *      Copyright © 1994 AmiTCP/IP Group,
   6  *                       Network Solutions Development Inc.
   7  *                       All rights reserved.
   8  */
   9
  10 #include <ios1.h>
  11 #include <fcntl.h>
  12 #include <stdlib.h>
  13 #include <dos.h>
  14 #include <errno.h>
  15 #include <dos/dos.h>
  16 #include <proto/dos.h>
  17
  18 long
  19 __lseek(int fd, long rpos, int mode)
  20 {
  21   struct UFB *ufb;
  22   long        apos;
  23
  24   /*
  25    * Check for the break signals
  26    */
  27   __chkabort();
  28   /*
  29    * find the ufb *
  30    */
  31   if ((ufb = __chkufb(fd)) == NULL) {
  32     errno = EINVAL;
  33     return -1;
  34   }
  35
  36   _OSERR = 0;
  37
  38   if (ufb->ufbflg & UFB_SOCK) {
  39     errno = ESPIPE; /* illegal seek */
  40     return -1;
  41   }
  42
  43   if ((apos = Seek(ufb->ufbfh, rpos, mode - 1)) == -1) {
  44     _OSERR = IoErr();
  45     errno = EIO;
  46     return -1;
  47   }
  48
  49   switch (mode) {
  50   case 0:
  51     return rpos;
  52   case 1:
  53     return apos + rpos;
  54   case 2:
  55     return Seek(ufb->ufbfh, 0, 0);
  56   }
  57 }