Re: [PATCH] issue #532 read-only admin area

Karl Fogel <kfogel@newton.ch.collab.net> writes:

> > I'll move the code in question into apr_file_set_read_only() in io.c
> > like so
>
> Even if no one has provided the Win32 know-how in APR yet, we could
> still at least put the skeleton in place and have the Unix side done.
> I think that would be better than adding a WIN32 conditional to
> Subversion, considering that the minimal APR change here is so
> trivial.

Damn! That means I need to think of a complete interface instead of
just one function ;-)

Well, Branko suggested

  apr_file_(get|set)_perms
  apr_file_(get|set)_read_only
  apr_file_(get|set)_executable

First, APR already has apr_file_set_perms:

  apr_status_t apr_file_perms_set(const char *fname, apr_fileperms_t perms);

and it provides apr_stat to get the perms, so that interface is
complete, and the (possibly buggy!) Unix implementation is
available. I assume a Win32 implementation could be provided.

Now APR doesn't appear to have a boolean type so in keeping with the
rest of APR:

  #define APR_FILE_ATTRIBUTE_READONLY 0x01
  #define APR_FILE_ATTRIBUTE_EXECUTABLE 0x02

  /* Holds or'ed values of APR_FILE_ATTRIBUTE_... */
  typedef apr_int32_t apr_fileattributes_t;

  apr_status_t apr_file_set_attributes(char const *fname,
                                       apr_fileattributes_t attributes);
  apr_status_t apr_file_get_attributes(char const *fname,
                                       apr_fileattributes_t *attributes);

These have fairly obvious implementations in terms of
apr_file_perms_set and apr_stat on Unix. I assume a Win32
implementation could be provided.

However, this get/set interface doesn't allow Unix to set readonly
differently for user, group, world and any attempt to make it do so
just reinvents apr_file_perms_set. So what I don't understand is why
Win32 cannot simply do the right thing 'under the hood' of
apr_file_perms_set. This is documented to return APR_INCOMPLETE and
APR_ENOTIMPL if the platform cannot fully comply. It gets 3 sets of
read/write/execute flags, Win32 could ignore or extrapolate from those
as required. If it needs to set an ACL as well as a permission can
apr_file_perms_set not do that? What exactly is the Win32 readonly and
executable interface? Can someone with Win32 knowledge contribute?
Why is more than apr_file_perms_set required?

-- 
Philip
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