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Date: Wed, 5 Nov 2008 15:12:12 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: haradats@nttdata.co.jp, linux-security-module@vger.kernel.org,
       linux-kernel@vger.kernel.org, takedakn@nttdata.co.jp,
       penguin-kernel@I-love.SAKURA.ne.jp
Subject: Re: [TOMOYO #12 (2.6.28-rc2-mm1) 04/11] Introduce d_realpath().
Message-Id: <20081105151212.9c6053eb.akpm@linux-foundation.org>
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	<20081104060948.233911964@nttdata.co.jp>
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On Tue, 04 Nov 2008 15:08:51 +0900
Kentaro Takeda <takedakn@nttdata.co.jp> wrote:

> +		/*
> +		 * Exception: Use /proc/self/ rather than /proc/\$/
> +		 * for current process.
> +		 */
> +		name = dentry->d_name.name;
> +		name_len = dentry->d_name.len;
> +		if (IS_ROOT(parent) &&
> +		    parent->d_sb->s_magic == PROC_SUPER_MAGIC &&
> +		    !strict_strtoul(name, 10, &pid)) {

Well that looks like rather a hack.

It would still be a hack, but a better implementation might be to save
the procfs superblock's address in a global then do


#ifdef CONFIG_PROCFS
static inline bool is_procfs_sb(struct super_block *sb)
{
	return sb == saved_procfs_sb;
}
#else
static inline bool is_procfs_sb(struct super_block *sb)
{
	return false;
}
#endif