CVS: rdesktop disk.c,1.38,1.39

Update of /cvsroot/rdesktop/rdesktop
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv30175

Modified Files:
	disk.c 
Log Message:
Support for file systems that cannot handle O_EXCL.


Index: disk.c
===================================================================
RCS file: /cvsroot/rdesktop/rdesktop/disk.c,v
retrieving revision 1.38
retrieving revision 1.39
diff -C2 -d -r1.38 -r1.39
*** disk.c	21 Oct 2004 08:28:03 -0000	1.38
--- disk.c	28 Oct 2004 07:46:39 -0000	1.39
***************
*** 192,195 ****
--- 192,245 ----
  }
  
+ /* Just like open(2), but if a open with O_EXCL fails, retry with
+    GUARDED semantics. This might be necessary because some filesystems
+    (such as NFS filesystems mounted from a unfsd server) doesn't
+    support O_EXCL. GUARDED semantics are subject to race conditions,
+    but we can live with that.
+ */
+ static int
+ open_weak_exclusive(const char *pathname, int flags, mode_t mode)
+ {
+ 	int ret;
+ 	struct stat statbuf;
+ 
+ 	ret = open(pathname, flags, mode);
+ 	if (ret != -1 || !(flags & O_EXCL))
+ 	{
+ 		/* Success, or not using O_EXCL */
+ 		return ret;
+ 	}
+ 
+ 	/* An error occured, and we are using O_EXCL. In case the FS
+ 	   doesn't support O_EXCL, some kind of error will be
+ 	   returned. Unfortunately, we don't know which one. Linux
+ 	   2.6.8 seems to return 524, but I cannot find a documented
+ 	   #define for this case. So, we'll return only on errors that
+ 	   we know aren't related to O_EXCL. */
+ 	switch (errno)
+ 	{
+ 		case EACCES:
+ 		case EEXIST:
+ 		case EINTR:
+ 		case EISDIR:
+ 		case ELOOP:
+ 		case ENAMETOOLONG:
+ 		case ENOENT:
+ 		case ENOTDIR:
+ 			return ret;
+ 	}
+ 
+ 	/* Retry with GUARDED semantics */
+ 	if (stat(pathname, &statbuf) != -1)
+ 	{
+ 		/* File exists */
+ 		errno = EEXIST;
+ 		return -1;
+ 	}
+ 	else
+ 	{
+ 		return open(pathname, flags & ~O_EXCL, mode);
+ 	}
+ }
  
  /* Enumeration of devices from rdesktop.c        */
***************
*** 335,339 ****
  		}
  
! 		handle = open(path, flags, mode);
  		if (handle == -1)
  		{
--- 385,389 ----
  		}
  
! 		handle = open_weak_exclusive(path, flags, mode);
  		if (handle == -1)
  		{



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