Re: [PATCH v2 2/3] Linux: Implement a useful version of _startup_fatal

[Florian Weimer <fweimer@redhat.com>]

* Adhemerval Zanella:

> On 04/05/2022 13:48, Florian Weimer wrote:
>> 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.
>> +   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)                                         \
>> +  do                                                                    \
>> +    {                                                                   \
>> +      size_t message_length = __builtin_strlen (message);               \
>
> Shoudn't we use double underscore name to avoid clash with local
> variables?

I think it's a problem only if message expands to something that uses
message_length, which is as likely as __message_length.  message can't
be a complex expression anyway because we don't want to call strlen at
this point.

Thanks,
Florian