Re: CFA: pseudo-reloc v2

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Oct  3 13:59, Charles Wilson wrote:
> #1) Using fprintf and mingw-specific error messages. This is bad, even
> if they are guarded by DEBUG:
> 
> #ifdef DEBUG
>       fprintf (stderr, "internal mingw runtime error:"
>                "psuedo_reloc version %d is unknown to this runtime.\n",
>                (int) v2_hdr->version);
> #endif
> 
> Maybe something like
> 
> #if defined(__INSIDE_CYGWIN__)
>      system_printf (
>         "Relocation error: invalid pseudo_reloc version %d.",
>         int) v2_hdr->version);
> #else
> #if defined(DEBUG) && defined(__MINGW32__)
>       fprintf (stderr, "internal mingw runtime error:"
>                "psuedo_reloc version %d is unknown to this runtime.\n",
>                (int) v2_hdr->version);
> #endif

The strace feature under the hood of system_printf is only available
from within the Cygwin DLL itself.  The pseudo_reloc.c file is not part
of the DLL, it's linked into the application.  Above all, the strace
fetaure is only accessible from C++ code.

So, actually fprintf(stderr) is more correct.  However, it's not safe to
assume that stdio has already been initialized when the runtime
relocator runs.  AFAICS, the relocator is called before dll_crt0_1 is
called and only in that latter function, the stdio descriptors are
initialized.

Failing relocation is as bad as any other error starting an application.
Wouldn't it be the right thing to raise an exception, along the lines of
the Windows exception which is raised when a loadtime linked DLL can't
be loaded?

> #2) __write_memory() does this:
>   assert (VirtualQuery (addr, &b, sizeof(b)));

Same problem here.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat