Subject: Re: filehandle
To: YAMAMOTO Takashi <>
From: Martin Husemann <>
List: tech-kern
Date: 07/21/2006 22:49:58
On Fri, Jul 21, 2006 at 07:10:20PM +0100, David Laight wrote:
> So you continue to export fhandle_y, but don't expose the header file
> that defines any contents.

Hmmm, we could actually define a special version (completely independend
of the kernel fhandle_t) for userland:

  typedef struct fhandle {
      size_t fh_size;
  } fhandle_t;

and then use small libc wrappers around the real syscall, that keep the
old signature:

  int fhopen(fhandle_t *fh, int flags)
      return fhopen2(((char*)fh)+sizeof(fhandle_t), fh->fh_size, flags);


  int getfh2(const char *path, fhandle_t *fh, size_t *fh_size)
     int err;
     size_t s = *fh_size;

     if (s > sizeof(fhandle_t))
        s -= sizeof(fhandle_t);
     err = sys__getfh30(path, ((char*)fh)+sizeof(fhandle_t), &s);
     if (err == 0)
        fh->fh_size = s;
     *fh_size = s + sizeof(fhandle_t);

But I'm not realy sure I like this.