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From: Florian Weimer <fw@deneb.enyo.de>
To: Rich Felker <dalias@libc.org>
Cc: Ariadne Conill <ariadne@dereferenced.org>,  musl@lists.openwall.com
Subject: Re: [musl] perhaps we should add re[c]allocarray?
Date: Tue, 21 Jul 2020 20:58:04 +0200	[thread overview]
Message-ID: <87pn8or8zn.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20200721183945.GQ14669@brightrain.aerifal.cx> (Rich Felker's message of "Tue, 21 Jul 2020 14:39:46 -0400")

* Rich Felker:

> recallocarray presumably needs to zero the new part which means it
> needs to know the old exact size, which means it depends on having
> either knowledge of implementation internals or a working, exact
> malloc_usable_size (AFAIK all legacy/existing ones except musl
> mallocng are broken and return a value greater than the originally
> allocated size).

The caller has to pass the old member count to recallocarray, in an
additional argument.  I think this avoids this particular issue, and
also makes it easy to achive interposition-safety.

  reply	other threads:[~2020-07-21 18:58 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-21 10:18 Ariadne Conill
2020-07-21 16:56 ` Markus Wichmann
2020-07-21 17:27   ` Hadrien Lacour
2020-07-21 23:19   ` Ariadne Conill
2020-07-21 18:39 ` Rich Felker
2020-07-21 18:58   ` Florian Weimer [this message]
2020-07-21 20:40     ` Rich Felker
2020-07-21 23:21       ` Ariadne Conill
2020-07-22  0:21         ` Rich Felker
2020-07-22  0:24           ` Ariadne Conill
2020-07-21 19:40   ` Leah Neukirchen

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