Re: sys_siglist[] is causing us trouble again

On Wed, Jul 15, 2020 at 7:48 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> As of a couple days ago, buildfarm member caiman (Fedora rawhide)
> is failing like this in all the pre-v12 branches:
>
> ccache gcc -Wall -Wmissing-prototypes -Wpointer-arith
> -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute
> -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard
> -Wno-format-truncation -Wno-stringop-truncation -g -O2 -DFRONTEND
> -I../../src/include -D_GNU_SOURCE -I/usr/include/libxml2 -c -o
> wait_error.o wait_error.c
> wait_error.c: In function \342\200\230wait_result_to_str\342\200\231:
> wait_error.c:71:6: error: \342\200\230sys_siglist\342\200\231 undeclared
> (first use in this function)
> 71 | sys_siglist[WTERMSIG(exitstatus)] : "(unknown)");
> | ^~~~~~~~~~~
> wait_error.c:71:6: note: each undeclared identifier is reported only once
> for each function it appears in
> make[2]: *** [<builtin>: wait_error.o] Error 1
>
> We haven't changed anything, ergo something changed at the OS level.
>
> Oddly, we'd not get to this code unless configure set
> HAVE_DECL_SYS_SIGLIST, so it's defined *somewhere*. I suspect the root
> issue here is some rearrangement of system header files combined with
> wait_error.c (and maybe other places?) not including exactly the same
> headers that configure tested.
>
> Anyway, rather than installing rawhide and trying to debug this,
> I'd like to make a modest proposal: let's back-patch the v12
> patches that made us stop relying on sys_siglist[], viz a73d08319
> and cc92cca43. Per the discussions that led to those patches,
> it's been decades since any platform didn't have POSIX-compliant
> strsignal(), so we'd be much better off relying on that.
>
> regards, tom lane
>

I believe it's related with these recent glibc changes at rawhide.
https://src.fedoraproject.org/rpms/glibc/c/0aab7eb58528999277c626fc16682da179de03d0?branch=master

- signal: Move sys_errlist to a compat symbol
- signal: Move sys_siglist to a compat symbol
SHA512 (glibc-2.31.9000-683-gffb17e7ba3.tar.xz) =
103ff3c04de5dc149df93e5399de1630f6fff1b8d7f127881d6e530492b8b953a8064205ceecb311a77c0a10de3a5ab2056121fd1fa833a30327c6b1f08beacc