From patchwork Mon Jan 31 16:36:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12730875 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61D34C433F5 for ; Mon, 31 Jan 2022 16:36:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380512AbiAaQgs (ORCPT ); Mon, 31 Jan 2022 11:36:48 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:46956 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349716AbiAaQgs (ORCPT ); Mon, 31 Jan 2022 11:36:48 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 623F4608C1 for ; Mon, 31 Jan 2022 16:36:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1208C340EE; Mon, 31 Jan 2022 16:36:47 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1nEZfa-00BYap-Ra; Mon, 31 Jan 2022 11:36:46 -0500 From: Steven Rostedt To: linux-trace-devel@vger.kernel.org Cc: "Steven Rostedt (Google)" Subject: [PATCH 3/4] libtracefs: Check README to know if we should do old onmatch format Date: Mon, 31 Jan 2022 11:36:41 -0500 Message-Id: <20220131163642.2754485-4-rostedt@goodmis.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20220131163642.2754485-1-rostedt@goodmis.org> References: <20220131163642.2754485-1-rostedt@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: "Steven Rostedt (Google)" Older kernels use: onmatch(..).synth_event(...) Where the "synth_event" is the synthetic event that was created. The new format uses: onmatch(..).trace(synth_event,...) Where it uses the new "trace" command and the synthetic event is the first parameter. The tracefs README can determine which format is used. Search the README and if the string "trace(,param list)" is found, then we know that the kernel uses the new format. Yes, the README in the tracefs file system *is* an ABI. Fixes: 7c9000c7495b9 ("libtracefs: Create a way to create a synthetic event") Signed-off-by: Steven Rostedt (Google) --- src/tracefs-hist.c | 38 +++++++++++++++++++++++++++++++++++--- 1 file changed, 35 insertions(+), 3 deletions(-) diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c index 622fe5c98c41..ec63b88a0bca 100644 --- a/src/tracefs-hist.c +++ b/src/tracefs-hist.c @@ -674,6 +674,7 @@ struct action { * @end_filters: The fields in the end event to record * @start_parens: Current parenthesis level for start event * @end_parens: Current parenthesis level for end event + * @new_format: onmatch().trace(synth_event,..) or onmatch().synth_event(...) */ struct tracefs_synth { struct tracefs_instance *instance; @@ -702,6 +703,7 @@ struct tracefs_synth { int *start_type; char arg_name[16]; int arg_cnt; + bool new_format; }; /* @@ -949,6 +951,26 @@ static int alloc_synthetic_event(struct tracefs_synth *synth) return synth->dyn_event ? 0 : -1; } +/* + * See if it is onmatch().trace(synth_event,...) or + * onmatch().synth_event(...) + */ +static bool has_new_format() +{ + char *readme; + char *p; + int size; + + readme = tracefs_instance_file_read(NULL, "README", &size); + if (!readme) + return false; + + p = strstr(readme, "trace(,param list)"); + free(readme); + + return p != NULL; +} + /** * tracefs_synth_alloc - create a new tracefs_synth instance * @tep: The tep handle that holds the events to work on @@ -1037,6 +1059,8 @@ struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep, synth = NULL; } + synth->new_format = has_new_format(); + return synth; } @@ -1730,13 +1754,21 @@ static char *create_trace(char *hist, struct tracefs_synth *synth) char *name; int i; - hist = append_string(hist, NULL, ".trace("); - hist = append_string(hist, NULL, synth->name); + if (synth->new_format) { + hist = append_string(hist, NULL, ".trace("); + hist = append_string(hist, NULL, synth->name); + hist = append_string(hist, NULL, ","); + } else { + hist = append_string(hist, NULL, "."); + hist = append_string(hist, NULL, synth->name); + hist = append_string(hist, NULL, "("); + } for (i = 0; synth->synthetic_args && synth->synthetic_args[i]; i++) { name = synth->synthetic_args[i]; - hist = append_string(hist, NULL, ","); + if (i) + hist = append_string(hist, NULL, ","); hist = append_string(hist, NULL, name); }