File name too long

[Paul Slootman]

On Mon 10 Mar 2003, jw schultz wrote:
> 
> What you have done is hit a file created by something insane
> where the filename is 252 characters long.  Adding the
> prepended . and the appended .XXXXXX made it 260 characters
> long and the filesystem doesn't support that long a name.

Correct analysis.

> I have a recollection of someone suggesting a patch to
> so our use of mkstemp didn't increase the length of long
> filenames but i don't recall anything coming of that.
> 
> The easiest solution would be for the file creator to stop
> making such long file names.  If you cannot do that i have

That's just fixing the symptoms, not the cause of the problem...

> attached a patch against CVS with a quick hack that avoids
> the problem as long as you don't use --temp-dir.
> 
> > I've already posted this bug in debian bug tracking system 
> > (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=183667)
> > but maybe I have to do it here as well...
> 
> It isn't really a debian problem although maybe one of their
> developers would create a better fix than i just did.

By a coincidence I'm currently looking at the open bugs on the Debian
rsync package. I'm a Debian developer, although not the one that is in
charge of rsync. That developer is apparently short of time so he can't
properly maintain rsync at the moment, so I'm seeing whether I can fix
anything in the meantime.

Here's the patch I came up with for this. I did a bit too much I guess;
the get_tmpname function had most code duplicated in the branches with and
without tmpdir, and I hate that so I eliminated it...  I also added
comments (horror!)

What's not fixed is if the pathname of the tmpfile in the tmpdir is too
long (without the added gunk for the template). I haven't looked into
the tmpdir thing at all yet. However, I expect that that shouldn't be
too difficult to fix as well, if it's even necessary.

With this patch, I can successfully transfer a file that has a 255-char
filename.

Only thing that may be a problem is the NAME_MAX thing, but that's a
POSIX thing, so should be relatively safe (famous last words).


Paul Slootman

diff -ru orig/rsync-2.5.6/receiver.c rsync-2.5.6/receiver.c
--- orig/rsync-2.5.6/receiver.c	2003-01-21 00:32:17.000000000 +0100
+++ rsync-2.5.6/receiver.c	2003-03-10 17:03:47.000000000 +0100
@@ -166,37 +166,49 @@
 
 static int get_tmpname(char *fnametmp, char *fname)
 {
-	char *f;
-
-	/* open tmp file */
-	if (tmpdir) {
-		f = strrchr(fname,'/');
-		if (f == NULL) 
-			f = fname;
-		else 
-			f++;
-		if (strlen(tmpdir)+strlen(f)+10 > MAXPATHLEN) {
-			rprintf(FERROR,"filename too long\n");
-			return 0;
-		}
-		snprintf(fnametmp,MAXPATHLEN, "%s/.%s.XXXXXX",tmpdir,f);
-		return 1;
-	} 
-
-	f = strrchr(fname,'/');
+	char	*f;
+	int	slash = 0;	/* restore the '/' ? */
+	char	x = 0;		/* restore the shortened name (with this?) */
+	char	*dir = "";	/* what dir to put the temp file in */
+
+	if (tmpdir)
+		dir = tmpdir;
+	f = strrchr(fname,'/');	/* is there a directory to skip in fname? */
+	if (f == NULL) {
+		f = fname;		/* no */
+	}
+	else {
+		slash++;		/* yes */
+		*f = 0;
+		f++;
+		dir = fname;
+	}
 
-	if (strlen(fname)+9 > MAXPATHLEN) {
+	if (strlen(dir)+strlen(f)+1 > MAXPATHLEN) {
 		rprintf(FERROR,"filename too long\n");
 		return 0;
 	}
 
-	if (f) {
-		*f = 0;
-		snprintf(fnametmp,MAXPATHLEN,"%s/.%s.XXXXXX",
-			 fname,f+1);
+	if (strlen(f)+8 > NAME_MAX || strlen(dir)+strlen(f)+9 > MAXPATHLEN) {
+		/* temporarily shorten the name, it's just for a temp name anyway */
+		x = f[NAME_MAX-10];
+		f[NAME_MAX-10] = 0;
+	}
+
+	/* construct temp name template */
+	if (*dir) {
+		snprintf(fnametmp, MAXPATHLEN, "%s/.%s.XXXXXX", dir, f);
+	} 
+	else {
+		snprintf(fnametmp, MAXPATHLEN, ".%s.XXXXXX", f);
+	}
+
+	if (x)
+		f[NAME_MAX-10] = x; /* restore the name if necessary */
+
+	if (slash) {	/* restore slash if necessary */
+		f--;
 		*f = '/';
-	} else {
-		snprintf(fnametmp,MAXPATHLEN,".%s.XXXXXX",fname);
 	}
 
 	return 1;