Re: CVS commit: src/lib/libc/stdlib

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Thu, Nov 02, 2017 at 08:26:58PM +0100, Kamil Rytarowski wrote:
> On 02.11.2017 20:15, Joerg Sonnenberger wrote:
> > On Thu, Nov 02, 2017 at 08:15:01PM +0100, Joerg Sonnenberger wrote:
> >> On Thu, Nov 02, 2017 at 06:37:15PM +0000, Kamil Rytarowski wrote:
> >>> Module Name:	src
> >>> Committed By:	kamil
> >>> Date:		Thu Nov  2 18:37:15 UTC 2017
> >>>
> >>> Modified Files:
> >>> 	src/lib/libc/stdlib: atexit.c
> >>>
> >>> Log Message:
> >>> Correct handling of __cxa_atexit(a,b,NULL) in libc
> >>
> >> I don't get it. This seems to be quite wrong.
> >>
> >>> Correct a bug that __cxa_atexit(x,y,NULL) is handled in the same way as
> >>> atexit(x) (which is simplified to __cxa_atexit(x,NULL,NULL).
> >>
> >> __cxa_atexit(x,y,NULL) is not invalid. Please revert this.
> > 
> > ...is invalid, of course.
> > 
> > Joerg
> > 
> 
> What's the rationale for being wrong?

The DSO handle is a required part of the (external) __cxa_atexit interface.
The atexit mapping is an implementation detail and not part of the public
interface. Doing it directly creates UB as it involves casting function
pointers between incompatible types.

Joerg