From patchwork Tue Jun 8 21:27:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12308195 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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 1066FC4743F for ; Tue, 8 Jun 2021 21:29:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6F5061375 for ; Tue, 8 Jun 2021 21:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231830AbhFHVaw (ORCPT ); Tue, 8 Jun 2021 17:30:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:41968 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234102AbhFHV3j (ORCPT ); Tue, 8 Jun 2021 17:29:39 -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 ADD5660FF0; Tue, 8 Jun 2021 21:27:45 +0000 (UTC) Date: Tue, 8 Jun 2021 17:27:44 -0400 From: Steven Rostedt To: Linux Trace Devel Cc: Julia Lawall Subject: [PATCH v2] libtraceevent: Handle parsing of "(REC)->" case Message-ID: <20210608172744.796e93b7@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: "Steven Rostedt (VMware)" If a trace event wraps the special __entry variable to dereference it with parenthesis, it shows up in the trace event format file wrapping the "(REC)" as well. For example, the "func_repeats" event passed the __entry into a helper macro in the TP_printk() portion, and the macro correctly wrapped its parameter in parenthesis. This caused the output to show: "(((u64)(REC)->top_delta_ts << 32) | (REC)->bottom_delta_ts)" The parser then failed to parse the "(REC)->" portion, as it expected the "->" to appear directly after the "REC". This is not a requirement, and the parser should be able to handle such cases. When this occurred, trace-cmd would error with the following message: trace-cmd: No such file or directory Error: expected type 4 but read 5 Fixes: 6582b0a ("tools/events: Add files to create libtraceevent.a") Reported-by: Julia Lawall Signed-off-by: Steven Rostedt (VMware) --- Changes since v1: Update the change log to show the error message, in case it happens again, it can be something to reference. src/event-parse.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/src/event-parse.c b/src/event-parse.c index 97c1a97..1217491 100644 --- a/src/event-parse.c +++ b/src/event-parse.c @@ -2311,8 +2311,19 @@ process_entry(struct tep_event *event __maybe_unused, struct tep_print_arg *arg, char *field; char *token; - if (read_expected(TEP_EVENT_OP, "->") < 0) - goto out_err; + type = read_token_item(&token); + /* + * Check if REC happens to be surrounded by parenthesis, and + * return if that's the case, as "(REC)->" is valid. + * but return TEP_EVENT_ITEM. + */ + if (type == TEP_EVENT_DELIM && strcmp(token, ")") == 0) { + *tok = token; + return TEP_EVENT_ITEM; + } + + if (test_type_token(type, token, TEP_EVENT_OP, "->")) + goto out_free; if (read_expect_type(TEP_EVENT_ITEM, &token) < 0) goto out_free; @@ -2338,7 +2349,6 @@ process_entry(struct tep_event *event __maybe_unused, struct tep_print_arg *arg, out_free: free_token(token); - out_err: *tok = NULL; return TEP_EVENT_ERROR; } @@ -3033,6 +3043,17 @@ process_paren(struct tep_event *event, struct tep_print_arg *arg, char **tok) if (type == TEP_EVENT_ERROR) goto out_free; + /* + * If REC is surrounded by parenthesis, the process_arg() + * will return TEP_EVENT_ITEM with token == ")". In + * this case, we need to continue processing the item + * and return. + */ + if (type == TEP_EVENT_ITEM && strcmp(token, ")") == 0) { + free_token(token); + return process_entry(event, arg, tok); + } + if (test_type_token(type, token, TEP_EVENT_DELIM, ")")) goto out_free;