From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9FB77FBF3 for ; Mon, 15 May 2023 16:57:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22E81C433EF; Mon, 15 May 2023 16:57:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684169831; bh=Kd0NWkY0y7jCOTkO6lIGUyZ2q02mDPaJKTU8wMhqGfQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e2OHw+cvquEtb1p2M4TCFGkf4m1+S8EPHbOGBNpzMgct+m1sO7/wf9vPIjCFfoy7h 7fJKNbn9quLsgUVYM0fcW140tHlqgJl9tD2BI00Y73S1QzXVnLNstg0LgJqtiXroJb zNu1mstcRzy+v5xfWe5ECltl4CyIhfF8UeLTwzYk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christian Brauner , Kefeng Wang , Luis Chamberlain Subject: [PATCH 6.3 155/246] proc_sysctl: update docs for __register_sysctl_table() Date: Mon, 15 May 2023 18:26:07 +0200 Message-Id: <20230515161727.205115750@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161722.610123835@linuxfoundation.org> References: <20230515161722.610123835@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Luis Chamberlain commit 67ff32289acad9ed338cd9f2351b44939e55163e upstream. Update the docs for __register_sysctl_table() to make it clear no child entries can be passed. When the child is true these are non-leaf entries on the ctl table and sysctl treats these as directories. The point to __register_sysctl_table() is to deal only with directories not part of the ctl table where thay may riside, to be simple and avoid recursion. While at it, hint towards using long on extra1 and extra2 later. Cc: stable@vger.kernel.org # v5.17 Cc: Christian Brauner Cc: Kefeng Wang Signed-off-by: Luis Chamberlain Signed-off-by: Greg Kroah-Hartman --- fs/proc/proc_sysctl.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1287,7 +1287,7 @@ out: * __register_sysctl_table - register a leaf sysctl table * @set: Sysctl tree to register on * @path: The path to the directory the sysctl table is in. - * @table: the top-level table structure + * @table: the top-level table structure without any child * * Register a sysctl table hierarchy. @table should be a filled in ctl_table * array. A completely 0 filled entry terminates the table. @@ -1308,9 +1308,12 @@ out: * proc_handler - the text handler routine (described below) * * extra1, extra2 - extra pointers usable by the proc handler routines + * XXX: we should eventually modify these to use long min / max [0] + * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org * * Leaf nodes in the sysctl tree will be represented by a single file - * under /proc; non-leaf nodes will be represented by directories. + * under /proc; non-leaf nodes (where child is not NULL) are not allowed, + * sysctl_check_table() verifies this. * * There must be a proc_handler routine for any terminal nodes. * Several default handlers are available to cover common cases - @@ -1352,7 +1355,7 @@ struct ctl_table_header *__register_sysc spin_lock(&sysctl_lock); dir = &set->dir; - /* Reference moved down the diretory tree get_subdir */ + /* Reference moved down the directory tree get_subdir */ dir->header.nreg++; spin_unlock(&sysctl_lock); @@ -1369,6 +1372,11 @@ struct ctl_table_header *__register_sysc if (namelen == 0) continue; + /* + * namelen ensures if name is "foo/bar/yay" only foo is + * registered first. We traverse as if using mkdir -p and + * return a ctl_dir for the last directory entry. + */ dir = get_subdir(dir, name, namelen); if (IS_ERR(dir)) goto fail;