From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Bossart, Nathan" <bossartn@amazon.com>
cc: "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Subject: Re: Improving psql's \password command
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Comments: In-reply-to "Bossart, Nathan" <bossartn@amazon.com>
	message dated "Thu, 11 Nov 2021 16:04:02 +0000"
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Date: Thu, 11 Nov 2021 11:11:51 -0500
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"Bossart, Nathan" <bossartn@amazon.com> writes:
> On 10/29/21, 5:07 PM, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
>> I was afraid somebody would say that.  I have looked at it, but AFAICS
>> we'd have to duplicate all of sprompt.c and nearly all of pg_get_line.c
>> in order to tie it into psql's SIGINT infrastructure, since we wouldn't
>> dare enable the signal handler except during the innermost fgets() call,
>> and if we did get a signal we'd still need to clean up the terminal echo
>> state, so we couldn't just longjmp out of simple_prompt().  The
>> cost/benefit ratio of that doesn't look very good.

> Hm.  Is it really necessary to duplicate all of sprompt.c and
> pg_get_line.c?  Would it be possible to teach the existing functions
> how to optionally enable SIGINT handling instead?  I wouldn't mind
> trying my hand at this if it seems like a reasonable approach.

It seems to me it'd overcomplicate simple_prompt's API for one use-case
... but if you want to try it, step right up.  (I suppose some of that
objection could be overcome by making simple_prompt into a wrapper
around another function not_so_simple_prompt.)

			regards, tom lane