Re: Bug with pg_ctl -w/wait and config-only directories

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Magnus Hagander <magnus(at)hagander(dot)net>, Peter Eisentraut <peter_e(at)gmx(dot)net>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, "Mr(dot) Aaron W(dot) Swenson" <titanofold(at)gentoo(dot)org>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Bug with pg_ctl -w/wait and config-only directories
Date: 2011-10-04 15:12:35
Message-ID: 201110041512.p94FCaE15821@momjian.us
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Robert Haas wrote:
> On Tue, Oct 4, 2011 at 10:55 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> >> It seems both ugly and unnecessary to declare dump_config_variable as
> >> char[MAXPGPATH]. ?MAXPGPATH doesn't seem like the right length for a
> >> buffer intended to hold a GUC name, but in fact I don't think you need
> >> a buffer at all. ?I think you can just declare it as char * and say
> >> dump_config_variable = optarg. getopt() doesn't overwrite the input
> >> argument vector, does it?
> >
> > Well, as I remember, it writes a null byte at the end of the argument
> > and then passes the pointer to the start --- when it advances to the
> > next argument, it removes the null, so the pointer might still be valid,
> > but does not have proper termination (or maybe that's what strtok()
> > does). ?However, I can find no documentation that mentions this
> > restriction, so perhaps it is old and no longer valid.
> >
> > If you look in our code you will see tons of cases of:
> >
> > ? ? ? ?user = strdup(optarg);
> > ? ? ? ?pg_data = xstrdup(optarg);
> > ? ? ? ?my_opts->dbname = mystrdup(optarg);
> >
> > However, I see other cases where we just assign optarg and optarg is a
> > string, e.g. pg_dump:
> >
> > ? ? ? ?username = optarg;
> >
> > Doing a Google search shows both types of coding in random code pieces.
> >
> > Are the optarg string duplication calls unnecessary and can be removed?
> > Either that, or we need to add some.
>
> Well, if you want to keep it, I'd suggest using malloc() to get an
> appropriate size buffer (not palloc) rather than using some arbitrary
> constant for the length.

The new code does strdup(), which will match what is passed.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

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