From: Markus Wichmann <nullplan@gmx.net>
To: musl@lists.openwall.com
Subject: Re: [musl] [PATCH] implement recallocarray(3)
Date: Sat, 1 Aug 2020 17:52:28 +0200 [thread overview]
Message-ID: <20200801155228.GC2076@voyager> (raw)
In-Reply-To: <20200801144658.6634-1-ariadne@dereferenced.org>
On Sat, Aug 01, 2020 at 08:46:58AM -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;
> +
> + if (new_size <= old_size) {
> + memset((char *) ptr + new_size, 0, old_size - new_size);
> + }
> +
> + newptr = reallocarray(ptr, m, n);
> + if (new_size > old_size) {
> + memset((char *) ptr + old_size, 0, new_size - old_size);
> + }
> +
> + return newptr;
> +}
Is there a reason for the call to reallocarray? The multiplication m * n
has already been tested for overflow and executed at that point. Might
as well just call realloc() there, right?
JM2C,
Markus
next prev parent reply other threads:[~2020-08-01 15:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-01 14:46 Ariadne Conill
2020-08-01 15:52 ` Markus Wichmann [this message]
2020-08-01 16:23 ` Ariadne Conill
2020-08-01 17:46 ` Rich Felker
2020-08-01 17:51 ` Ariadne Conill
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