Applied, thanks!
Sergey Bugaev, le mer. 03 janv. 2024 20:14:40 +0300, a ecrit:
> Instead of relying on the stack frame layout to figure out where the stack
> pointer was prior to the _hurd_stack_setup () call, just pass the pointer
> as an argument explicitly. This is less brittle and much more portable.
>
> Signed-off-by: Sergey Bugaev
> ---
> sysdeps/mach/hurd/i386/static-start.S | 3 +++
> sysdeps/mach/hurd/x86/init-first.c | 16 +++-
> sysdeps/mach/hurd/x86_64/static-start.S | 1 +
> 3 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/sysdeps/mach/hurd/i386/static-start.S
> b/sysdeps/mach/hurd/i386/static-start.S
> index d83505b2..3ffcb47d 100644
> --- a/sysdeps/mach/hurd/i386/static-start.S
> +++ b/sysdeps/mach/hurd/i386/static-start.S
> @@ -19,7 +19,10 @@
> .text
> .globl _start
> _start:
> + pushl %esp
> call _hurd_stack_setup
> + /* No need to "addl %4, %esp", since _hurd_stack_setup
> + * returns with an already adjusted stack pointer. */
> xorl %edx, %edx
> jmp _start1
>
> diff --git a/sysdeps/mach/hurd/x86/init-first.c
> b/sysdeps/mach/hurd/x86/init-first.c
> index bb051418..6f71d71b 100644
> --- a/sysdeps/mach/hurd/x86/init-first.c
> +++ b/sysdeps/mach/hurd/x86/init-first.c
> @@ -197,7 +197,7 @@ strong_alias (posixland_init, __libc_init_first);
> which should not exist at all. */
> void
> inhibit_stack_protector
> -_hurd_stack_setup (void)
> +_hurd_stack_setup (void **argptr)
> {
>/* This is the very first C code that runs in a statically linked
> executable -- calling this function is the first thing that _start in
> @@ -206,14 +206,12 @@ _hurd_stack_setup (void)
>
> _start1 expects the arguments, environment, and a Hurd data block to be
> located at the top of the stack. The data may already be located there,
> - or we may need to receive it from the exec server. */
> - void *caller = __builtin_extract_return_addr (__builtin_return_address
> (0));
> - /* If the arguments and environment are already located on the stack, this
> is
> - where they are, just above our call frame. Note that this may not be a
> - valid pointer in case we're supposed to receive the arguments from the
> exec
> - server, so we can not dereference it yet. */
> - void **p = (void **) __builtin_frame_address (0) + 2;
> + or we may need to receive it from the exec server. If the data is
> located
> + on the stack (just above our call frame), argptr points to it. Note
> that
> + this may not be a valid pointer in case we're supposed to receive the
> + arguments from the exec server, so we can not dereference it yet. */
>
> + void *caller = __builtin_extract_return_addr (__builtin_return_address
> (0));
>/* Init the essential things. */
>first_init ();
>
> @@ -245,7 +243,7 @@ _hurd_stack_setup (void)
> the stack pointer to the data (which is somewhere on the current stack
> anyway). This way, _start1 find the data on the top of the stack, just
> as
> it expects to. */
> - _hurd_startup (p, );
> + _hurd_startup (argptr, );
>__builtin_unreachable ();
> }
> #endif
> diff --git a/sysdeps/mach/hurd/x86_64/static-start.S
> b/sysdeps/mach/hurd/x86_64/static-start.S
> index 9b9db937..0ec00905 100644
> --- a/sysdeps/mach/hurd/x86_64/static-start.S
> +++ b/sysdeps/mach/hurd/x86_64/static-start.S
> @@ -25,6 +25,7 @@ _start:
> leaq __strlen_sse2(%rip), %rax
> movq %rax, strlen@GOTPCREL(%rip)
>
> + movq %rsp, %rdi
> call _hurd_stack_setup
> xorq %rdx, %rdx
> jmp _start1
> --
> 2.43.0
>
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
