From: Wolf <wolf@wolfsden.cz>
To: musl@lists.openwall.com
Cc: Ariadne Conill <ariadne@dereferenced.org>
Subject: Re: [musl] [PATCH v4] implement recallocarray(3)
Date: Mon, 3 Aug 2020 17:11:50 +0200 [thread overview]
Message-ID: <20200803151150.wv4zbj7jkwjdfsvp@wolfsden.cz> (raw)
In-Reply-To: <20200802225426.32002-1-ariadne@dereferenced.org>
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On 2020-08-02 16:54:26 -0600, Ariadne Conill wrote:
> +void *recallocarray(void *ptr, size_t om, size_t m, size_t n)
> +{
> + void *newptr;
> + size_t old_size, new_size;
> +
> + if (n && m > -1 / n) {
> + errno = ENOMEM;
> + return 0;
> + }
> + new_size = m * n;
> +
> + if (n && om > -1 / n) {
> + errno = EINVAL;
> + return 0;
> + }
> + old_size = om * n;
> +
> + newptr = calloc(m, n);
> + if (!newptr)
> + return ptr;
From reading openbsd's source I would say this should return 0 (or
newptr), not ptr. Otherwise I'm not sure how the caller could tell if
the resize failed or not.
> +
> + if (new_size <= old_size) {
> + memcpy((char *) newptr, ptr, new_size);
> + }
> + else {
> + memcpy((char *) newptr, ptr, old_size);
> + memset((char *) newptr + old_size, 0, new_size - old_size);
> + }
> +
> + memset(ptr, 0, old_size);
> + free(ptr);
> +
> + return newptr;
> +}
W.
--
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.
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next prev parent reply other threads:[~2020-08-03 15:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-02 22:54 Ariadne Conill
2020-08-03 0:45 ` Rich Felker
2020-08-03 1:35 ` Ariadne Conill
2020-08-03 1:58 ` Rich Felker
2020-08-03 15:11 ` Wolf [this message]
2020-08-03 15:15 ` Wolf
2020-08-03 15:25 ` Rich Felker
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