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To: Magnus Hagander <magnus@hagander.net>
cc: Andrew Dunstan <andrew@dunslane.net>, Bruce Momjian <bruce@momjian.us>,
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Subject: Re: [HACKERS] Moving tablespaces 
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Comments: In-reply-to Magnus Hagander <magnus@hagander.net>
	message dated "Tue, 06 Dec 2011 16:39:51 +0100"
Date: Tue, 06 Dec 2011 11:07:56 -0500
Message-ID: <21564.1323187676@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Magnus Hagander <magnus@hagander.net> writes:
> There is some nice precedent in the CREATE TABLESPACE command (though
> dependent on HAVE_SYMLINK and not HAVE_READLINK), so I'm just going to
> copy the error message from there.

Fair enough.

Looking at the existing readlink use in port/exec.c, it strikes me that
another thing you'd better do is include a check for buffer overrun,
ie the test needs to be more like

		rllen = readlink(fname, link_buf, sizeof(link_buf));
		if (rllen < 0 || rllen >= sizeof(link_buf))
			... fail ...

Also, you're assuming that the result is already null-terminated,
which is incorrect.

			regards, tom lane