os.path.expanduser ignores os.seteuid

[Sean 'Shaleh' Perry]

On 04-Jun-2002 Graham Guttocks wrote:
> Why doesn't os.path.expanduser pay attention to the fact that I've
> changed the process's effective user id?
> 
> As root:
> 
> Python 2.1.3 (#1, Apr 11 2002, 18:30:30) 
> [GCC 2.95.3 20010315 (release) [FreeBSD]] on freebsd4
> Type "copyright", "credits" or "license" for more information.
>>>> import os
>>>> os.seteuid(667)
>>>> os.path.expanduser("~")
> '/root'
>>>> 
> 
> Other functions like os.getlogin() don't have this problem.
> 

def expanduser(path):
    """Expand ~ and ~user constructions.  If user or $HOME is unknown,
    do nothing."""
    if path[:1] != '~':
        return path
    i, n = 1, len(path)
    while i < n and path[i] != '/':
        i = i + 1
    if i == 1:
        if not os.environ.has_key('HOME'):
            return path
        userhome = os.environ['HOME']
    else:
        import pwd
        try:
            pwent = pwd.getpwnam(path[1:i])
        except KeyError:
            return path
        userhome = pwent[5]
    if userhome[-1:] == '/': i = i + 1
    return userhome + path[i:]

is from python 2.2.  It uses short circuit eval for the '~' case and simply
reads the environment $HOME.  If you could pass '~user/' it would give you the
answer you want.