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Date: Sun, 25 Aug 2019 17:53:38 +0200
From: Quentin Rameau <quinq@fifth.space>
To: pgsql-hackers@postgresql.org
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [PATCH] Fix missing argument handling in psql getopt
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In-Reply-To: <14042.1566745352@sss.pgh.pa.us>
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Precedence: bulk

Hello Tom,

> > When passing an argument option with a missing argument, strcmp
> > would be called with the argv terminating NULL. =20
>=20
> Um ... so how would control get there with optind too large?

That's from the getopt specification[0]:

=E2=80=9CIf the option was the last character in the string pointed to by an
element of argv, then optarg shall contain the next element of argv,
and optind shall be incremented by 2. If the resulting value of optind
is greater than argc, this indicates a missing option-argument, and
getopt() shall return an error indication.=E2=80=9D

So in the case of =E2=80=9Cpsql -h=E2=80=9C, optarg points to argv[2] and o=
ptind is set
to 3 (optind is initialized to 1, then incremented by 2).

> What test case/platform are you considering?

Test case is just running psql -h.
The bug has been exposed by testing psql on musl.

> (There really shouldn't be *any* case where getopt advances
> optind past argc, imo.)

Actually that's the typical error case, as per the specification quoted
above.

[0] https://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html