Horton

Re: convert libpgport's pqsignal() to a void function

Nathan Bossart <nathandbossart@gmail.com>

View thread View on postgr.es
From: Nathan Bossart <nathandbossart@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Fujii Masao <masao.fujii@oss.nttdata.com>, Andy Fan <zhihuifan1213@163.com>, pgsql-hackers@lists.postgresql.org
Date: 2025-01-15T19:47:18Z
Lists: pgsql-hackers 
On Thu, Jan 16, 2025 at 08:21:08AM +1300, Thomas Munro wrote:
> On Thu, Jan 16, 2025 at 8:15 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
>> On Tue, Jan 14, 2025 at 11:08:05PM -0500, Tom Lane wrote:
>> > I wonder why we redefine those values?
>>
>> I wondered the same.  Those redefines have been there since commit 5049196,
>> but I haven't been able to find any real discussion in the archives about
>> it.  Maybe I will bug Magnus about it sometime, in case he happens to
>> remember the reason.
> 
> My guess would be: perhaps some ancient version of MinGW didn't define
> them?  They're defined by MinGW and native signal.h now and they have
> the same values, so we should remove them I think.

Okay.  If nothing else, it'd be interesting to see what the buildfarm
thinks.

> Assertion failed: 0, file ../src/port/pqsignal.c, line 147
> 
> Could be due to calling native signal() with a signal number other
> than the 6 values required to work by the C standard?

Looking closer, that probably makes more sense than my SIG_ERR redefinition
theory.  If that assertion is getting hit, that means signal() _is_
returning SIG_ERR (either the system one or our redefined version), and it
looks like it's pretty common to use -1 for SIG_ERR.  That'd only affect
Windows frontend programs, but it still sounds scary.  I'll try getting
more details about the error with some custom cfbot runs.

-- 
nathan

Commits

  1. Remove redefinitions of SIG_* macros in win32_port.h.

  2. Convert libpgport's pqsignal() to a void function.

  3. Avoid calling pqsignal() with invalid signals on Windows frontends.

  4. Avoid symbol collisions between pqsignal.c and legacy-pqsignal.c.

  5. Check that MyProcPid == getpid() in backend signal handlers.

  6. Further refactoring of c.h and nearby files.

  7. Here's the latest win32 signals code, this time in the form of a patch

  8. Add C version of initdb, from Andrew Dunstan.

  9. Allow Win32 to compile under MinGW. Major changes are: