imap/src/osdep/unix/crx_std.c

   1 /* ========================================================================
   2  * Copyright 1988-2006 University of Washington
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  *
  11  * ========================================================================
  12  */
  13
  14 /*
  15  * Program:     Exclusive create of a file
  16  *
  17  * Author:      Mark Crispin
  18  *              Networks and Distributed Computing
  19  *              Computing & Communications
  20  *              University of Washington
  21  *              Administration Building, AG-44
  22  *              Seattle, WA  98195
  23  *              Internet: MRC@CAC.Washington.EDU
  24  *
  25  * Date:        17 December 1999
  26  * Last Edited: 30 August 2006
  27  */
  28 \f
  29 /* Exclusive create of a file
  30  * Accepts: file name
  31  * Return: T if success, NIL if failed, -1 if retry
  32  */
  33
  34 long crexcl (char *name)
  35 {
  36   int i;
  37   int mask = umask (0);
  38   long ret = LONGT;
  39                                 /* try to get the lock */
  40   if ((i = open (name,O_WRONLY|O_CREAT|O_EXCL,(int) shlock_mode)) < 0)
  41     ret = (errno == EEXIST) ? -1 : NIL;
  42   else close (i);               /* made the file, now close it */
  43   umask (mask);                 /* restore previous mask */
  44   return LONGT;                 /* success */
  45 }