[PATCH] ntdll: Implement RtlCaptureStackBackTrace() for x86_64.

[Zebediah Figura]

For what it's worth:

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=40868
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47101

On 7/31/19 4:57 PM, Chip Davis wrote:
> Signed-off-by: Chip Davis <cdavis at codeweavers.com>
> ---
>   dlls/ntdll/signal_x86_64.c | 111 ++++++++++++++++++++++++++++++++++++-
>   1 file changed, 109 insertions(+), 2 deletions(-)
> 
> diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c
> index b024de76421..94412302152 100644
> --- a/dlls/ntdll/signal_x86_64.c
> +++ b/dlls/ntdll/signal_x86_64.c
> @@ -4436,13 +4436,120 @@ __ASM_GLOBAL_FUNC( RtlRaiseException,
>                      "call " __ASM_NAME("RtlRaiseStatus") /* does not return */ );
>   
>   
> +static inline ULONG hash_pointers( void **ptrs, ULONG count )
> +{
> +    /* Based on MurmurHash2, which is in the public domain */
> +    static const ULONG m = 0x5bd1e995;
> +    static const ULONG r = 24;
> +    ULONG hash = count * sizeof(void*);
> +    for (; count > 0; ptrs++, count--)
> +    {
> +        ULONG_PTR data = (ULONG_PTR)*ptrs;
> +        ULONG k1 = (ULONG)(data & 0xffffffff), k2 = (ULONG)(data >> 32);
> +        k1 *= m;
> +        k1 = (k1 ^ (k1 >> r)) * m;
> +        k2 *= m;
> +        k2 = (k2 ^ (k2 >> r)) * m;
> +        hash = (((hash * m) ^ k1) * m) ^ k2;
> +    }
> +    hash = (hash ^ (hash >> 13)) * m;
> +    return hash ^ (hash >> 15);
> +}
> +
> +
>   /*************************************************************************
>    *		RtlCaptureStackBackTrace (NTDLL.@)
>    */
>   USHORT WINAPI RtlCaptureStackBackTrace( ULONG skip, ULONG count, PVOID *buffer, ULONG *hash )
>   {
> -    FIXME( "(%d, %d, %p, %p) stub!\n", skip, count, buffer, hash );
> -    return 0;
> +    UNWIND_HISTORY_TABLE table;
> +    DISPATCHER_CONTEXT dispatch;
> +    CONTEXT context;
> +    LDR_MODULE *module;
> +    NTSTATUS status;
> +    ULONG i;
> +    USHORT num_entries = 0;
> +
> +    TRACE( "(%u, %u, %p, %p)", skip, count, buffer, hash );
> +
> +    RtlCaptureContext( &context );
> +    dispatch.TargetIp      = 0;
> +    dispatch.ContextRecord = &context;
> +    dispatch.HistoryTable  = &table;
> +    if (hash) *hash = 0;
> +    for (i = 0; i < skip + count; i++)
> +    {
> +        /* FIXME: should use the history table to make things faster */
> +
> +        dispatch.ImageBase = 0;
> +        dispatch.ControlPc = context.Rip;
> +        dispatch.ScopeIndex = 0;
> +
> +        /* first look for PE exception information */
> +
> +        if ((dispatch.FunctionEntry = lookup_function_info( dispatch.ControlPc, &dispatch.ImageBase, &module )))
> +        {
> +            RtlVirtualUnwind( UNW_FLAG_NHANDLER, dispatch.ImageBase, dispatch.ControlPc,
> +                              dispatch.FunctionEntry, &context, &dispatch.HandlerData,
> +                              &dispatch.EstablisherFrame, NULL );
> +            goto unwind_done;
> +        }
> +
> +        /* then look for host system exception information */
> +
> +        if (!module || (module->Flags & LDR_WINE_INTERNAL))
> +        {
> +            BOOL got_info = FALSE;
> +            struct dwarf_eh_bases bases;
> +            const struct dwarf_fde *fde = _Unwind_Find_FDE( (void *)(dispatch.ControlPc - 1), &bases );
> +
> +            if (fde)
> +            {
> +                status = dwarf_virtual_unwind( dispatch.ControlPc, &dispatch.EstablisherFrame, &context,
> +                                               fde, &bases, &dispatch.LanguageHandler, &dispatch.HandlerData );
> +                if (status != STATUS_SUCCESS) return status;
> +                got_info = TRUE;
> +            }
> +#ifdef HAVE_LIBUNWIND_H
> +            else
> +            {
> +                status = libunwind_virtual_unwind( dispatch.ControlPc, &got_info, &dispatch.EstablisherFrame, &context,
> +                                                   &dispatch.LanguageHandler, &dispatch.HandlerData );
> +                if (status != STATUS_SUCCESS) return i;
> +            }
> +#endif
> +
> +            if (got_info)
> +            {
> +                dispatch.FunctionEntry = NULL;
> +                goto unwind_done;
> +            }
> +        }
> +        else WARN( "exception data not found in %s\n", debugstr_w(module->BaseDllName.Buffer) );
> +
> +        context.Rip = *(ULONG64 *)context.Rsp;
> +        context.Rsp = context.Rsp + sizeof(ULONG64);
> +        dispatch.EstablisherFrame = context.Rsp;
> +
> +    unwind_done:
> +        if (!dispatch.EstablisherFrame) break;
> +
> +        if ((dispatch.EstablisherFrame & 7) ||
> +            dispatch.EstablisherFrame < (ULONG64)NtCurrentTeb()->Tib.StackLimit ||
> +            dispatch.EstablisherFrame > (ULONG64)NtCurrentTeb()->Tib.StackBase)
> +        {
> +            ERR( "invalid frame %lx (%p-%p)\n", dispatch.EstablisherFrame,
> +                 NtCurrentTeb()->Tib.StackLimit, NtCurrentTeb()->Tib.StackBase );
> +            break;
> +        }
> +
> +        if (context.Rsp == (ULONG64)NtCurrentTeb()->Tib.StackBase) break;
> +
> +        if (i >= skip) buffer[num_entries++] = (void *)context.Rip;
> +    }
> +    if (hash && num_entries > 0) *hash = hash_pointers( buffer, num_entries );
> +    TRACE( "captured %hu frames\n", num_entries );
> +    return num_entries;
>   }
>   
>   
>