linux-kernel - Re: [PATCH 3/3] firmware loader: allow distribution to choose default search paths

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Message-ID: <s5hwqq8u3o1.wl%tiwai@suse.de>
Date:	Wed, 05 Jun 2013 14:45:34 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Ming Lei <ming.lei@...onical.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 3/3] firmware loader: allow distribution to choose default search paths

At Wed, 5 Jun 2013 20:36:19 +0800,
Ming Lei wrote:
> 
> On Wed, Jun 5, 2013 at 7:57 PM, Takashi Iwai <tiwai@...e.de> wrote:
> >
> > Hmm, separating with semicolons isn't so common, but we can live with
> 
> Looks there are seldom such usage patterns in kernel, so could you let me
> know which separator is more common?

$PATH uses colon, but I don't know of many others.

> > it.  I thought the previous loop can be kept but just pass each member
> > to fw_get_file_firmware() unconditionally.  This will reduce the
> > changes, I guess.  But it's just a matter of taste, here is no
> > critically hot path, after all.
> 
> Yes, aother way is to move 'fw_path_para' out of fw_path[], and only
> let  fw_get_fw_file_from_paths() deal with 'fw_path_para' and
> CONFIG_FW_CUSTOMIZED_PATH. Looks it is still clean.

Why not just pass all strings to fw_get_fw_file_from_paths(), no
matter whether it's a single or multiple path strings?

static const char * const fw_path[] = {
	fw_path_para,
#ifdef CONFIG_FW_CUSTOMIZED_PATH
	CONFIG_FW_CUSTOMIZED_PATH,
#endif
	"/lib/firmware/updates/" UTS_RELEASE,
	"/lib/firmware/updates",
	"/lib/firmware/" UTS_RELEASE,
};

....

	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
		/* skip the unset customized path */
		if (!fw_path[i][0])
			continue;
		success = fw_get_fw_file_from_paths(fw_path[i], path, buf);
		if (success)
			break;
	}

> 
> 
> >> +             if (strstr(path, ".."))
> >> +                     continue;
> >
> > I expect you'll prepare this path sanity check part in a separate
> > patch, right?  It's basically independent from the new kconfig.
> 
> Yes, it will be submitted as another patch, also I plan to add
> the check on firmware_name in _request_firmware_prepare()
> so that the similar problem can be found earlier.

Sounds good.


Takashi
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