From patchwork Thu Dec 17 09:46:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Tzvetomir Stoyanov (VMware)" X-Patchwork-Id: 11979441 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=-20.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 308B7C2BB9A for ; Thu, 17 Dec 2020 09:47:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F304A238E1 for ; Thu, 17 Dec 2020 09:47:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727739AbgLQJrO (ORCPT ); Thu, 17 Dec 2020 04:47:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727755AbgLQJrN (ORCPT ); Thu, 17 Dec 2020 04:47:13 -0500 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 304BDC0611C5 for ; Thu, 17 Dec 2020 01:46:33 -0800 (PST) Received: by mail-wm1-x331.google.com with SMTP id g185so5109815wmf.3 for ; Thu, 17 Dec 2020 01:46:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=N48y4S6J5pzX7y2q8ngaSZvSJdDoFqsjVlLTD+/lKmc=; b=i7ugzBGGovHzrMIpXRpyrpdj+bVTj9h15d2lUQelOpPJwsE4tf7O8jKbLF4SUobKWS jPRRK3J9AlgzhmWkW3y2LUpEES2t1w7ATu7gK0dMyJuUGP5Vgv982XDvt31e03hft4Mx 7AAcyHQDmlp153DMVqlfXJ7CyVLqsLpLFf1ofIq5weSqEqKOKk2BQlCupQswuWrQybuR eOhPEvM1RoLdx991c8njCm+/tH6EuDrAJ49Ta/QL9eCyQdDId9NJ8GE6dZHjqcC3Mc71 AoDoM1+1S9+2hx3rcsEY8S5kOOm+1sPnz07bdh3N8Mu2eZ4vQrqoVKnkZbmQj8ZJQ14T bAEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=N48y4S6J5pzX7y2q8ngaSZvSJdDoFqsjVlLTD+/lKmc=; b=Inlf0b8B0MGKdZKew0ESknBOzxHUKXeGBS4c6DhXwXd+aARtAd0d4qJy1ZH34lspT5 9HeHWKGhqx3DfBrNAb5W9F+cu1YMHdS1qdYY8bCQV4rb4zYuPFa6g+LXiJYAD35vE6F/ lY188eq+fJHQOoPWsWM+jcM4DzKeENvqZL05CNzdspqMCu/1D0tOJKkwtwiuRp1HH6KM CVp27NfE6/AlwkUTKTc66T4s3GIr748VrhFWjsZ1d6UCpFjwBkQ/iWuKq++xNnO0odaC 4dmsMm+S81na3Y7QuWyRfym2BxW69rT6aJBcSFbFpfgc3yyQyvcmDH5GJJqXIJElqlCa Lw+w== X-Gm-Message-State: AOAM533IS02d2DXpOcKPAdKVzQvQo/GF75ugZ/vPvE8AyjAq7q1dVDhj 4GZdlmi+zb4cZNT7PeSgzhQ= X-Google-Smtp-Source: ABdhPJwzCpvtJibQQuN9gZf+y3+8JsQlCmrt+xcnKSx7XOVFPyrUrKGaRkrS5TsV3+FnF0rp+oSY4Q== X-Received: by 2002:a1c:9dd8:: with SMTP id g207mr7587209wme.15.1608198391858; Thu, 17 Dec 2020 01:46:31 -0800 (PST) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id o125sm6773164wmo.30.2020.12.17.01.46.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Dec 2020 01:46:31 -0800 (PST) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH 3/9] libtracefs man pages: APIs for locating trace directory and files. Date: Thu, 17 Dec 2020 11:46:20 +0200 Message-Id: <20201217094626.1402191-4-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201217094626.1402191-1-tz.stoyanov@gmail.com> References: <20201217094626.1402191-1-tz.stoyanov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Documented APIs: tracefs_get_tracing_file() tracefs_put_tracing_file() tracefs_get_tracing_dir() tracefs_find_tracing_dir() Signed-off-by: Tzvetomir Stoyanov (VMware) --- Documentation/libtracefs-files.txt | 111 +++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 Documentation/libtracefs-files.txt diff --git a/Documentation/libtracefs-files.txt b/Documentation/libtracefs-files.txt new file mode 100644 index 0000000..b288892 --- /dev/null +++ b/Documentation/libtracefs-files.txt @@ -0,0 +1,111 @@ +libtracefs(3) +============= + +NAME +---- +tracefs_get_tracing_file, tracefs_put_tracing_file, tracefs_get_tracing_dir, +tracefs_find_tracing_dir - Find locations of trace directory and files. + +SYNOPSIS +-------- +[verse] +-- +*#include * + +char pass:[*]*tracefs_get_tracing_file*(const char pass:[*]_name_); +void *tracefs_put_tracing_file*(char pass:[*]_name_); +const char pass:[*]*tracefs_get_tracing_dir*(void); +char pass:[*]*tracefs_find_tracing_dir*(void); +-- + +DESCRIPTION +----------- +This set of APIs can be used to find the full path of the trace file +system mount point and trace files in it. + +The _tracefs_get_tracing_file()_ function returns the full path of the +file with given _name_ in the trace file system. The function works +only with files in the trasefs main directory, it is not trace instance +aware. It is recommended to use _tracefs_instance_get_file()_ and +_tracefs_instance_get_dir()_ instead. The returned string must be freed +with _tracefs_put_tracing_file()_. + +The _tracefs_put_tracing_file()_ function frees trace file name, +returned by _tracefs_get_tracing_file()_. + +The _tracefs_find_tracing_dir()_ function finds the mount point of the +trace file system and returns a full path to it. If the file system is +not mounted, it will mount it. The returned string must be freed. + +The _tracefs_get_tracing_dir()_ function returns the full path to the +trace file system. In the first function call, the mount point of the +tracing file system is located, cached and returned. It will mount it, +if it is not minted. On any subsequent call the cached path is returned. +The return string must _not_ be freed. + +RETURN VALUE +------------ +The _tracefs_get_tracing_file()_ function returns a string or NULL in case +of an error. The returned string must be freed with _tracefs_put_tracing_file()_. + +The _tracefs_find_tracing_dir()_ function returns a string or NULL in case +of an error. The returned string must be freed. + +The _tracefs_get_tracing_dir()_ function returns a constant string or NULL +in case of an error. The returned string must _not_ be freed. + +EXAMPLE +------- +[source,c] +-- +#include +... +char *trace_on = tracefs_get_tracing_file("tracing_on"); + if (trace_on) { + ... + tracefs_put_tracing_file(trace_on); + } +... +char *trace_dir = tracefs_find_tracing_dir(); + if (trace_dir) { + ... + free(trace_dir); + } +... +const char *trace_dir = tracefs_get_tracing_dir(); + +-- +FILES +----- +[verse] +-- +*tracefs.h* + Header file to include in order to have access to the library APIs. +*-ltracefs* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +_libtracefs(3)_, +_libtraceevent(3)_, +_trace-cmd(1)_ + +AUTHOR +------ +[verse] +-- +*Steven Rostedt* +*Tzvetomir Stoyanov* +-- +REPORTING BUGS +-------------- +Report bugs to + +LICENSE +------- +libtracefs is Free Software licensed under the GNU LGPL 2.1 + +RESOURCES +--------- +https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/ \ No newline at end of file