Re: [PATCH] fs/9p/xattr.c: avoid format-overflow warning

[asmadeus@codewreck.org]

Christian Schoenebeck wrote on Mon, Oct 09, 2023 at 08:34:15PM +0200:
> > +++ b/fs/9p/xattr.c
> > @@ -139,7 +139,7 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
> >  
> >  ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
> >  {
> > -	return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
> > +	return v9fs_xattr_get(dentry, "", buffer, buffer_size);
> >  }
> >  
> >  static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
> > 
> 
> Mmm, that's not the same is it? Have you tested this change?
> 
> Currently this function causes a 'Txattrwalk' 9p message to be sent to 9p
> server with its name[s] field being NULL, and the latter being the magical
> hint to 9p server to not send an attribute, but rather the list of attributes.
> 
> With your change I would assume that it would rather ask server for one
> attribute called "". I have not tested myself, just worrying that it might
> break behaviour.

p9pdu_vwritef should output the same (just a 0 length) for both NULL and
"" so I think it should be ok, but it definitely needs testing.

I'll try to find time to check (getfattr -d should be enough) later this
week and add it to the pile

-- 
Dominique Martinet | Asmadeus