Re: [PATCH] fread does not return negative on error

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 23, 2009, 23:56 UTC
Message-ID: <7vhby64i8f.fsf@alter.siamese.dyndns.org>
In-Reply-To: <4A3FB479.2090902@lsrfire.ath.cx>

René Scharfe <rene.scharfe@lsrfire.ath.cx> writes:

> the following patch is for git.  I just removed the unneeded check for
> res == 0 from your version.  Does it look OK?

The patch looks good, and both of our in-tree users do error out when the returned value is 0 (imap-send.c checks with "<= 0" which looks a tad amateurish, though) correctly.

Funny, there is no caller of this function in the original context this bug originally found, which I think is linux-2.6/tools/perf ;-).

Thanks.

Show 23 quoted lines

> From: Roel Kluin <roel.kluin@gmail.com>
>
> size_t res cannot be less than 0. fread returns 0 on error.
>
> Reported-by: Ingo Molnar <mingo@elte.hu>
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
>  strbuf.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/strbuf.c b/strbuf.c
> index a884960..f03d117 100644
> --- a/strbuf.c
> +++ b/strbuf.c
> @@ -260,7 +260,7 @@ size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
>  	res = fread(sb->buf + sb->len, 1, size, f);
>  	if (res > 0)
>  		strbuf_setlen(sb, sb->len + res);
> -	else if (res < 0 && oldalloc == 0)
> +	else if (oldalloc == 0)
>  		strbuf_release(sb);
>  	return res;
>  }