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 

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 }