kern/128933: realpath(3) does not follow SUS specification for a NULL/empty path

[Andrey Chernov]

The following reply was made to PR kern/128933; it has been noted by GNATS.

From: Andrey Chernov <ache at nagual.pp.ru>
To: James Vega <vega.james at gmail.com>
Cc: freebsd-gnats-submit at freebsd.org
Subject: Re: kern/128933: realpath(3) does not follow SUS specification for
	a NULL/empty path
Date: Tue, 18 Nov 2008 12:06:12 +0300

 On Mon, Nov 17, 2008 at 02:04:59AM +0000, James Vega wrote:
 > According to the Single Unix Specification[0], the realpath stdlib function should return NULL (to indicate an error) when the first argument to realpath is either NULL or an empty string and set errno to EINVAL/ENOENT respectively.
 > 
 > For the empty string case, FreeBSD is currently populating resolved with the current working directory and returning the pointer to that.
 > 
 > For the NULL case, I see no check whether path is NULL or not.  Instead, the first use of it is dereferencing the pointer
 > 
 >   if (path[0] == '/'
 > 
 > [0] - http://www.opengroup.org/onlinepubs/009695399/functions/realpath.html
 
 The situation is even worse. realpath(3) breaks those SUS rules 
 ("shall fail if") too:
 
 [ENOENT] A component of file_name does not name an existing file 
 [ENOTDIR] A component of the path prefix is not a directory
 
 i.e. realpath(3) does not detect fictional file name (last component) 
 with ENOENT and does not detect intermediate non-directories components 
 with ENOTDIR.
 
 See following examples with realpath(1):
 
 # realpath /non_existent
 /non_existent
 (should be "No such file or directory")
 
 
 # realpath /bin/non_existent/cp
 realpath: /bin/non_existent/cp: No such file or directory
 (should be: "Not a directory", as early as non_existent checked)
 
 -- 
 http://ache.pp.ru/