Horton

Re: stopgap fix for signal handling during restore_command

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Thomas Munro <thomas.munro@gmail.com>, Michael Paquier <michael@paquier.xyz>, Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Fujii Masao <fujii@postgresql.org>, Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-03-01T04:36:03Z
Lists: pgsql-hackers 
On Sun, Feb 26, 2023 at 12:12:27PM -0800, Andres Freund wrote:
> On 2023-02-26 11:39:00 -0800, Nathan Bossart wrote:
>> What precisely did you have in mind?  AFAICT you are asking for a wrapper
>> around write().
> 
> Partially I just want something that can easily be searched for, that can have
> comments attached to it documenting why what it is doing is safe.
> 
> It'd not be a huge amount of work to have a slow and restricted string
> interpolation support, to make it easier to write messages. Converting floats
> is probably too hard to do safely, and I'm not sure %m can safely be
> supported. But basic things like %d would be pretty simple.
> 
> Basically a loop around the format string that directly writes to stderr using
> write(), and only supports a signal safe subset of normal format strings.

Got it, thanks.  I will try to put something together along these lines,
although I don't know if I'll pick up the interpolation support in this
thread.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Commits

  1. windows: msvc: Define STDIN/OUT/ERR_FILENO.

  2. Avoid calling proc_exit() in processes forked by system().

  3. Move extra code out of the Pre/PostRestoreCommand() section.