[PATCH 1/5] Linux: Implement a useful version of _startup_fatal
H.J. Lu
hjl.tools@gmail.com
Mon May 2 19:45:28 GMT 2022
On Mon, May 2, 2022 at 12:16 PM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> ---
> sysdeps/unix/sysv/linux/i386/startup.h | 17 ++----------
> sysdeps/unix/sysv/linux/startup.h | 38 ++++++++++++++++++++++++++
> 2 files changed, 40 insertions(+), 15 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/startup.h
>
> diff --git a/sysdeps/unix/sysv/linux/i386/startup.h b/sysdeps/unix/sysv/linux/i386/startup.h
> index 67c9310f3a..694d6cf4e7 100644
> --- a/sysdeps/unix/sysv/linux/i386/startup.h
> +++ b/sysdeps/unix/sysv/linux/i386/startup.h
> @@ -19,19 +19,6 @@
> #if BUILD_PIE_DEFAULT
> /* Can't use "call *%gs:SYSINFO_OFFSET" during statup in static PIE. */
> # define I386_USE_SYSENTER 0
> -
> -# include <sysdep.h>
> -# include <abort-instr.h>
> -
> -__attribute__ ((__noreturn__))
> -static inline void
> -_startup_fatal (const char *message __attribute__ ((unused)))
> -{
> - /* This is only called very early during startup in static PIE.
> - FIXME: How can it be improved? */
> - ABORT_INSTRUCTION;
> - __builtin_unreachable ();
> -}
> -#else
> -# include_next <startup.h>
> #endif
> +
> +#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?
> + do \
> + { \
> + size_t message_length = __builtin_strlen (message); \
> + if (! __builtin_constant_p (message_length)) \
> + { \
> + extern void _startup_fatal_not_constant (void); \
> + _startup_fatal_not_constant (); \
> + } \
> + INTERNAL_SYSCALL_CALL (write, STDERR_FILENO, message, message_length); \
> + INTERNAL_SYSCALL_CALL (exit_group, 127); \
> + } \
> + while (0)
> +#endif /* !SHARED */
> --
> 2.35.1
>
>
--
H.J.
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