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From: Jeff King <peff@peff.net>
To: Alexander Potashev <aspotashev@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>,
	Git Mailing List <git@vger.kernel.org>,
	Thomas Rast <trast@student.ethz.ch>
Subject: Re: [PATCH] diesys calls die and also reports strerror(errno)
Date: Thu, 4 Jun 2009 16:50:55 -0400	[thread overview]
Message-ID: <20090604205055.GB17478@sigill.intra.peff.net> (raw)
In-Reply-To: <1244081105-7149-1-git-send-email-aspotashev@gmail.com>

On Thu, Jun 04, 2009 at 06:05:05AM +0400, Alexander Potashev wrote:

> Firstly I was going to write a 'adapt_to_fmt' function which would
> double all inclusions of '%', and then use it for strerror(err) and
> make printf-like functions happy (actually 'die_routine').
> 
> BUT, Have you ever seen an error description containing '%'? I haven't.
> So, handling the case of '%'s is not worth injecting several dump lines
> into the sources of the Beatiful Content Tracker.

That makes me a little nervous. No, I don't think there are any '%'
signs in standard 'C' locale messages (at least not in GNU libc). But
what about other locales, especially ones which use a multi-byte
encoding?

Though your code does at least recognize the situation and does
something sane instead of feeding bogus parameters to fprintf.

> +void diesys(const char *err, ...)
> +{
> +	va_list params;
> +	char *fullfmt;
> +	const char *strerr;
> +
> +	va_start(params, err);
> +
> +	strerr = strerror(errno);
> +	if (strchr(strerr, '%'))
> +		strerr = "<error description contains '%%'>";
> +	fullfmt = xmalloc(strlen(err) + strlen(strerr) + 3);
> +	sprintf(fullfmt, "%s: %s", err, strerr);
> +	die_routine(fullfmt, params);
> +
> +	va_end(params);
> +}

Should we be calling malloc here? One of the possible error conditions
is that we're out of memory (though xmalloc itself just uses "die"). I
don't think there is a good reason not to use a reasonably-sized static
buffer, which should increase robustness (report() is already using a
1024-character buffer, so any message would be truncated there anyway).

-Peff

  reply	other threads:[~2009-06-04 20:51 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-02 21:34 [PATCH] add strerror(errno) to die() calls where applicable Thomas Rast
2009-06-03  1:55 ` Jeff King
     [not found]   ` <2325a7950906031855t1977448lbb1c8aa671c72f3d@mail.gmail.com>
2009-06-04  1:58     ` Alexander Potashev
2009-06-04 20:32       ` Jeff King
2009-06-04  2:05   ` [PATCH] diesys calls die and also reports strerror(errno) Alexander Potashev
2009-06-04 20:50     ` Jeff King [this message]
2009-06-04 21:13       ` Junio C Hamano
2009-06-05  6:25       ` Johannes Sixt
2009-06-05  7:12         ` Junio C Hamano
2009-06-06 22:09           ` Jeff King
2009-06-06 13:09   ` [PATCH] add strerror(errno) to die() calls where applicable Thomas Rast
2009-06-06 14:44     ` [PATCH v2 0/3] Thomas Rast <trast@student.ethz.ch> Thomas Rast
2009-06-08 21:02       ` [PATCH v3 0/3] die_errno() Thomas Rast
2009-06-27 15:58         ` [PATCH v4 0/4] die_errno() Thomas Rast
2009-06-27 15:58           ` [PATCH v4 1/4] Introduce die_errno() that appends strerror(errno) to die() Thomas Rast
2009-06-27 15:58           ` [PATCH v4 2/4] die_errno(): double % in strerror() output just in case Thomas Rast
2009-06-27 15:58           ` [PATCH v4 3/4] Convert existing die(..., strerror(errno)) to die_errno() Thomas Rast
2009-06-27 15:58           ` [PATCH v4 4/4] Use die_errno() instead of die() when checking syscalls Thomas Rast
2009-06-27 18:38           ` [PATCH v4 0/4] die_errno() Junio C Hamano
2009-06-08 21:02       ` [PATCH v3 1/3] Introduce die_errno() that appends strerror(errno) to die() Thomas Rast
2009-06-08 22:07         ` Jeff King
2009-06-09  8:22           ` Thomas Rast
2009-06-09  8:53             ` Jeff King
2009-06-09  9:29               ` Andreas Ericsson
2009-06-08 21:02       ` [PATCH v3 2/3] Convert existing die(..., strerror(errno)) to die_errno() Thomas Rast
2009-06-08 21:02       ` [PATCH v3 3/3] Use die_errno() instead of die() when checking syscalls Thomas Rast
2009-06-06 14:44     ` [PATCH v2 1/3] Introduce die_errno() that appends strerror(errno) to die() Thomas Rast
2009-06-06 20:36       ` Johannes Sixt
2009-06-06 20:56         ` Thomas Rast
2009-06-06 21:17           ` Johannes Sixt
2009-06-06 22:47           ` Jeff King
2009-06-06 22:13       ` Jeff King
2009-06-07 11:12         ` Alexander Potashev
2009-06-07 16:57           ` Junio C Hamano
2009-06-08 12:36             ` Jeff King
2009-06-08 15:35               ` Alexander Potashev
2009-06-08 22:04                 ` Jeff King
2009-06-06 14:44     ` [PATCH v2 2/3] Convert existing die(..., strerror(errno)) to die_errno() Thomas Rast
2009-06-06 20:31       ` Johannes Sixt
2009-06-06 14:44     ` [PATCH v2 3/3] Use die_errno() instead of die() when checking syscalls Thomas Rast
2009-06-06 21:02       ` Johannes Sixt
2009-06-06 22:27         ` Thomas Rast

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