From: NRK <nrk@disroot.org>
To: musl@lists.openwall.com
Cc: Tamir Duberstein <tamird@google.com>
Subject: Re: [musl] undefined behavior in fread.c
Date: Fri, 24 Feb 2023 19:55:11 +0600 [thread overview]
Message-ID: <20230224135511.iunglqtcvpjeqgtv@gen2.localdomain> (raw)
In-Reply-To: <20230224133413.GE4163@brightrain.aerifal.cx>
On Fri, Feb 24, 2023 at 08:34:14AM -0500, Rich Felker wrote:
> Is there any indication that passing NULL as the first argument to
> fread is not itself undefined?
C99 says the following:
| If size or nmemb is zero, fread returns zero and the contents of the
| array and the state of the stream remain unchanged.
It doesn't explicitly mention weather stream can be NULL or not in case
of 0 size/nmemb - but regardless, is there any actual reason for not
returning early?
The following should be OK as far as I see:
- if (!size) nmemb = 0;
+ if (!size || !nmemb) return 0;
or `if (!len) return 0;` could also work if multiplication overflow is
not a concern.
- NRK
next prev parent reply other threads:[~2023-02-24 13:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 12:52 Tamir Duberstein
2023-02-24 13:34 ` Rich Felker
2023-02-24 13:53 ` Jₑₙₛ Gustedt
2023-02-24 13:55 ` NRK [this message]
2023-02-24 14:07 ` Rich Felker
2023-02-24 14:17 ` NRK
2023-02-24 14:42 ` Tamir Duberstein
2023-02-24 15:13 ` NRK
2023-02-24 16:12 ` Tamir Duberstein
2023-02-24 16:40 ` Jₑₙₛ Gustedt
2023-02-24 16:42 ` Tamir Duberstein
2023-02-24 17:00 ` Jₑₙₛ Gustedt
2023-02-24 17:07 ` enh
2023-02-24 17:32 ` Tamir Duberstein
2023-02-24 16:42 ` enh
2023-02-24 20:07 ` Rich Felker
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