libs/liblock/locklockf.c

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