From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37539C433EB for ; Fri, 19 Mar 2021 18:38:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2105A61974 for ; Fri, 19 Mar 2021 18:38:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231214AbhCSSin (ORCPT ); Fri, 19 Mar 2021 14:38:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:59328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230351AbhCSSiD (ORCPT ); Fri, 19 Mar 2021 14:38:03 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E0B7C61991; Fri, 19 Mar 2021 18:38:02 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94) (envelope-from ) id 1lNK0X-0017nB-Ty; Fri, 19 Mar 2021 14:38:01 -0400 Message-ID: <20210319183801.808862244@goodmis.org> User-Agent: quilt/0.66 Date: Fri, 19 Mar 2021 14:34:38 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Yordan Karadzhov Subject: [for-next][PATCH 12/13] seq_buf: Add seq_buf_terminate() API References: <20210319183426.840228082@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" In the case that the seq_buf buffer needs to be printed directly, add a way to make sure that the buffer is safe to read by forcing a nul terminating character at the end of the string, or the last byte of the buffer if the string has overflowed. Signed-off-by: Steven Rostedt (VMware) --- include/linux/seq_buf.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h index 9d6c28cc4d8f..5b31c5147969 100644 --- a/include/linux/seq_buf.h +++ b/include/linux/seq_buf.h @@ -71,6 +71,31 @@ static inline unsigned int seq_buf_used(struct seq_buf *s) return min(s->len, s->size); } +/** + * seq_buf_terminate - Make sure buffer is nul terminated + * @s: the seq_buf descriptor to terminate. + * + * This makes sure that the buffer in @s is nul terminated and + * safe to read as a string. + * + * Note, if this is called when the buffer has overflowed, then + * the last byte of the buffer is zeroed, and the len will still + * point passed it. + * + * After this function is called, s->buffer is safe to use + * in string operations. + */ +static inline void seq_buf_terminate(struct seq_buf *s) +{ + if (WARN_ON(s->size == 0)) + return; + + if (seq_buf_buffer_left(s)) + s->buffer[s->len] = 0; + else + s->buffer[s->size - 1] = 0; +} + /** * seq_buf_get_buf - get buffer to write arbitrary data to * @s: the seq_buf handle -- 2.30.1