1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/osdep/unix/crx_nfs.c	Mon Sep 14 15:17:45 2009 +0900
     1.3 @@ -0,0 +1,79 @@
     1.4 +/* ========================================================================
     1.5 + * Copyright 1988-2006 University of Washington
     1.6 + *
     1.7 + * Licensed under the Apache License, Version 2.0 (the "License");
     1.8 + * you may not use this file except in compliance with the License.
     1.9 + * You may obtain a copy of the License at
    1.10 + *
    1.11 + *     http://www.apache.org/licenses/LICENSE-2.0
    1.12 + *
    1.13 + * 
    1.14 + * ========================================================================
    1.15 + */
    1.16 +
    1.17 +/*
    1.18 + * Program:	Exclusive create of a file, NFS kludge version
    1.19 + *
    1.20 + * Author:	Mark Crispin
    1.21 + *		Networks and Distributed Computing
    1.22 + *		Computing & Communications
    1.23 + *		University of Washington
    1.24 + *		Administration Building, AG-44
    1.25 + *		Seattle, WA  98195
    1.26 + *		Internet: MRC@CAC.Washington.EDU
    1.27 + *
    1.28 + * Date:	17 December 1999
    1.29 + * Last Edited:	30 August 2006
    1.30 + */
    1.31 +
    1.32 +
    1.33 +/* SUN-OS had an NFS, As kludgy as an albatross;
    1.34 + * And everywhere that it was installed, It was a total loss.
    1.35 + *  -- MRC 9/25/91
    1.36 + */
    1.37 +
    1.38 +/* Exclusive create of a file
    1.39 + * Accepts: file name
    1.40 + * Return: T if success, NIL if failed, -1 if retry
    1.41 + */
    1.42 +
    1.43 +long crexcl (char *name)
    1.44 +{
    1.45 +  long ret = -1;
    1.46 +  int i;
    1.47 +  char hitch[MAILTMPLEN];
    1.48 +  struct stat sb;
    1.49 +  int mask = umask (0);
    1.50 +				/* build hitching post file name */
    1.51 +  sprintf (hitch,"%s.%lu.%d.",name,(unsigned long) time (0),getpid ());
    1.52 +  i = strlen (hitch);		/* append local host name */
    1.53 +  gethostname (hitch + i,(MAILTMPLEN - i) - 1);
    1.54 +				/* try to get hitching-post file */
    1.55 +  if ((i = open (hitch,O_WRONLY|O_CREAT|O_EXCL,(int) shlock_mode)) >= 0) {
    1.56 +    close (i);			/* close the hitching-post */
    1.57 +    /* Note: link() may return an error even if it actually succeeded.  So we
    1.58 +     * always check for success via the link count, and ignore the error if
    1.59 +     * the link count is right.
    1.60 +     */
    1.61 +				/* tie hitching-post to lock */
    1.62 +    i = link (hitch,name) ? errno : 0;
    1.63 +				/* success if link count now 2 */
    1.64 +    if (!stat (hitch,&sb) && (sb.st_nlink == 2)) ret = LONGT;
    1.65 +    else if (i == EPERM) {	/* links not allowed? */
    1.66 +      /* Probably a FAT filesystem on Linux.  It can't be NFS, so try creating
    1.67 +       * the lock file directly.
    1.68 +       */
    1.69 +      if ((i = open (name,O_WRONLY|O_CREAT|O_EXCL,(int) shlock_mode)) >= 0){
    1.70 +	close (i);		/* close the file */
    1.71 +	ret = LONGT;		/* success */
    1.72 +      }
    1.73 +				/* fail unless error is EEXIST */
    1.74 +      else if (errno != EEXIST) ret = NIL;
    1.75 +    }
    1.76 +    unlink (hitch);		/* flush hitching post */
    1.77 +  }
    1.78 +				/* fail unless error is EEXIST */
    1.79 +  else if (errno != EEXIST) ret = NIL;
    1.80 +  umask (mask);			/* restore previous mask */
    1.81 +  return ret;
    1.82 +}