Re: [PATCH 1/5] Linux: Implement a useful version of _startup_fatal

[Florian Weimer <fweimer@redhat.com>]

* H. J. Lu:

> On Mon, May 2, 2022 at 12:53 PM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> * H. J. Lu:
>>
>> >> +#include_next <startup.h>
>> >> diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
>> >> new file mode 100644
>> >> index 0000000000..a5de941759
>> >> --- /dev/null
>> >> +++ b/sysdeps/unix/sysv/linux/startup.h
>> >> @@ -0,0 +1,38 @@
>> >> +/* Linux definitions of functions used by static libc main startup.
>> >> +   Copyright (C) 2017-2022 Free Software Foundation, Inc.
>> >                              Shouldn't it just be 2022?
>> >> +   This file is part of the GNU C Library.
>> >> +
>> >> +   The GNU C Library is free software; you can redistribute it and/or
>> >> +   modify it under the terms of the GNU Lesser General Public
>> >> +   License as published by the Free Software Foundation; either
>> >> +   version 2.1 of the License, or (at your option) any later version.
>> >> +
>> >> +   The GNU C Library is distributed in the hope that it will be useful,
>> >> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> >> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> >> +   Lesser General Public License for more details.
>> >> +
>> >> +   You should have received a copy of the GNU Lesser General Public
>> >> +   License along with the GNU C Library; if not, see
>> >> +   <https://www.gnu.org/licenses/>.  */
>> >> +
>> >> +#ifdef SHARED
>> >> +# include_next <startup.h>
>> >> +#else
>> >> +# include <sysdep.h>
>> >> +
>> >> +/* Avoid a run-time invocation of strlen.  */
>> >> +#define _startup_fatal(message)                                         \
>> >
>> > Is this needed only for static PIE?
>>
>> I don't know.  It's used from csu/libc-tls.c, some targets may need it
>> for ET_EXEC static linking, too.  I haven't checked.  The additional
>> code size is minimal.
>
> _startup_fatal was added for i386 static PIE.  I don't think it is
> needed for normal static executables.

Based on the current initialization ordering, it seems to me that we
need it for non-PIE static programs, too.  Maybe I should check this
tomorrow.

Thanks,
Florian