liblock/locklockf.c

   1 /*
   2 ** Copyright 1998 - 1999 Double Precision, Inc.  See COPYING for
   3 ** distribution information.
   4 */
   5
   6 /* $Id: locklockf.c,v 1.4 2002/09/02 16:55:56 mrsam Exp $ */
   7
   8 #if     HAVE_CONFIG_H
   9 #include        "config.h"
  10 #endif
  11 #include        <sys/types.h>
  12 #if     HAVE_FCNTL_H
  13 #include        <fcntl.h>
  14 #endif
  15 #if     HAVE_SYS_FCNTL_H
  16 #include        <sys/fcntl.h>
  17 #endif
  18 #if     HAVE_UNISTD_H
  19 #include        <unistd.h>
  20 #endif
  21 #if     HAVE_ERRNO_H
  22 #include        <errno.h>
  23 #endif
  24 #include        "liblock.h"
  25
  26 int     ll_lockfd(int fd, int ltype, LL_OFFSET_TYPE start, LL_OFFSET_TYPE len)
  27 {
  28 off_t   p;
  29
  30         if (ltype & ll_whence_curpos)
  31                 p=lseek(fd, start, SEEK_CUR);
  32         else if (ltype && ll_whence_end)
  33                 p=lseek(fd, start, SEEK_END);
  34         else    p=lseek(fd, start, SEEK_SET);
  35
  36         if (p < 0)      return (-1);
  37
  38         if (lockf(fd, ltype & ll_unlock ? F_ULOCK:
  39                 ltype & ll_wait ? F_LOCK:F_TLOCK, len))
  40         {
  41                 lseek(fd, p, SEEK_SET);
  42                 return (-1);
  43         }
  44         lseek(fd, SEEK_SET, p);
  45         return (0);
  46 }