libndr: Avoid assigning duplicate versions to symbols

[Andreas Schneider]

On Tuesday, 20 October 2020 08:49:18 CEST Amitay Isaacs via samba-technical 
wrote:
> Hi,
> 
> On freebsd 12, the linking of libndr.so fails with following error:
> 
> [ 918/3912] Linking bin/default/librpc/libndr.so
> ld: error: duplicate symbol '_ndr_pull_error' in version script
> ld: error: duplicate symbol '_ndr_push_error' in version script
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
> 
> This happened because symbols _ndr_push_error and _ndr_pull_error were
> added to abi_match in commit 42ac80fb46cfb485e8c4a26d455fa784fdd1daed.
> It generates the following snippet in ndr.vscript.
> 
> --------------------
> NDR_1.0.0 {
>         global:
>                 _ndr_pull_error;
>                 _ndr_push_error;
>                 ndr_print_steal_switch_value;
>                 ndr_push_steal_switch_value;
> } NDR_0.2.1;
> 
> NDR_1.0.1 {
>         global:
>                 ndr_*;
>                 GUID_*;
>                 _ndr_pull_error;
>                 _ndr_push_error;
>         local:
>                 ndr_table_*;
>                 _end;
>                 __bss_start;
>                 _edata;
>                 *;
> };
> --------------------
> 
> Symbols _ndr_push_error and _ndr_pull_error are added to both versions
> NDR_1.0.0 and NDR_1.0.1. This does not seem to be a problem for linux
> ld.  It seems to ignore the later version assignments to the same
> symbol as seen from the objdump:
> 
> $ objdump -T bin/default/librpc/libndr.so.1.0.1  | grep _ndr_pu.._error
> 0000000000012afe g    DF .text    0000000000000162  NDR_1.0.0  
> _ndr_push_error 0000000000012973 g    DF .text    000000000000018b 
> NDR_1.0.0   _ndr_pull_error
> 
> One solution is to avoid adding specific symbols to abi_match and only
> use wildcards in abi_match.  This avoids the need to modify wafsamba
> abi_write_vscript() function in samba_abi.py.  Patch is attached that
> changes the symbols _ndr_push_error and _ndr_pull_error to wildcard
> patterns as _ndr_push_error* and _ndr_pull_error*.

This looks fine for me, but I think we need a bug for 4.13 for that?


	Andreas

-- 
Andreas Schneider                      asn at samba.org
Samba Team                             www.samba.org
GPG-ID:     8DFF53E18F2ABC8D8F3C92237EE0FC4DCC014E3D