From patchwork Mon Dec 21 06:02:49 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: 11984257 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,URIBL_BLOCKED, 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 DB3B7C4332B for ; Mon, 21 Dec 2020 06:03:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEAC622B2D for ; Mon, 21 Dec 2020 06:03:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727837AbgLUGD6 (ORCPT ); Mon, 21 Dec 2020 01:03:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728050AbgLUGD5 (ORCPT ); Mon, 21 Dec 2020 01:03:57 -0500 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1BC3C0611CD for ; Sun, 20 Dec 2020 22:03:02 -0800 (PST) Received: by mail-ed1-x52b.google.com with SMTP id i24so8466038edj.8 for ; Sun, 20 Dec 2020 22:03:02 -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=KxK4jW156xLsSBmOYzmXTCWc9wZHIsV4UBpC0gCdWoQ=; b=Cp/QtCb3aYixgUoRk1n0JiO3O/v1p41mGeQ9DuI4ALwrzBZldD7BsEZGzb6EU+MOXF ytJAl5DpEC4GKDEjHmRvp2lcWIGqWrPeIrcETnkrK+8YQGJ+aUt/0nxiPNc/bJnZTLg1 9tX+BxMEEOI4M2kD6ddwD7AKng4de+bvPanl/hPrghGoWVr+sXw9LuYXu9VFI9eDZlCM lHcvE54wrKqfuNfYt4bEgoRD4mhH37VpGeBLhSAUrZC0FJV4oVRrtG+THr/dSq6TQml8 3VW29rdqGLC87LOjrt2ocW2w9ZLw2WTgTf/5nA6PSfv2/62CWnjfwEwfsJczDVcED791 gQ7g== 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=KxK4jW156xLsSBmOYzmXTCWc9wZHIsV4UBpC0gCdWoQ=; b=huiT13ykEHoGkQixSP4sGt2waATvJrZYiKgzrTJWEejGedQjdcsPmslX6djNe55PbO yM3hpe1eACgUS062siDMojoM53cbfydQRNgRfLTQh21OJuiYOjcFAy2l64ENIFzF8hUy JREm1pjjKWIi0HX5Zg++mMRJXa9XjnObFqmABSzYV29NssPGDt0sdHIHQGBlxNddGkal iM20wawE1vGY5qNBCsWmXhGlYfy5r15k+8lL+3icJFAtLKDZhOoLk/rcoNG5CtTzl1dw jT9O54Qc1ytn6QtaiCshDKToWbbA0JY9kx1HdAW91XjTsRKekqD/1g8INev6gVdzuVo1 XmGA== X-Gm-Message-State: AOAM532f+/Pt/xr4CTKqrZpRIDNZp4TpN40T0aVv/RLKV1d1sNfa+Dwi vXQBS408LW7cfFR77+EEYvUNy8tBg4QWl/pm X-Google-Smtp-Source: ABdhPJxHBP6Ifz+pEIHFg4jJQA/owawLZj6Hf6kstz6Dh0v8FfrwuDfTWh1UMlEsk+XuHmQRM2HOGw== X-Received: by 2002:aa7:d297:: with SMTP id w23mr14634300edq.374.1608530581628; Sun, 20 Dec 2020 22:03:01 -0800 (PST) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id z10sm8560885ejl.30.2020.12.20.22.03.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Dec 2020 22:03:00 -0800 (PST) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v2 5/8] libtracefs man pages: APIs for working with files in trace instances. Date: Mon, 21 Dec 2020 08:02:49 +0200 Message-Id: <20201221060252.177890-6-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201221060252.177890-1-tz.stoyanov@gmail.com> References: <20201221060252.177890-1-tz.stoyanov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Documented APIs: tracefs_file_exists() tracefs_dir_exists() tracefs_instance_get_file() tracefs_instance_get_dir() tracefs_instance_file_write() tracefs_instance_file_read() Signed-off-by: Tzvetomir Stoyanov (VMware) --- Documentation/libtracefs-instances-files.txt | 160 +++++++++++++++++++ 1 file changed, 160 insertions(+) create mode 100644 Documentation/libtracefs-instances-files.txt diff --git a/Documentation/libtracefs-instances-files.txt b/Documentation/libtracefs-instances-files.txt new file mode 100644 index 0000000..7f9d381 --- /dev/null +++ b/Documentation/libtracefs-instances-files.txt @@ -0,0 +1,160 @@ +libtracefs(3) +============= + +NAME +---- +tracefs_file_exists, tracefs_dir_exists, tracefs_instance_get_file, +tracefs_instance_get_dir, tracefs_instance_file_write, +tracefs_instance_file_read - Work with files in tracing instances. + +SYNOPSIS +-------- +[verse] +-- +*#include * + +bool *tracefs_file_exists*(struct tracefs_instance pass:[*]_instance_, char pass:[*]_name_); +bool *tracefs_dir_exists*(struct tracefs_instance pass:[*]_instance_, char pass:[*]_name_); +char pass:[*]*tracefs_instance_get_file*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_file_); +char pass:[*]*tracefs_instance_get_dir*(struct tracefs_instance pass:[*]_instance_); +int *tracefs_instance_file_write*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_file_, const char pass:[*]_str_); +char pass:[*]*tracefs_instance_file_read*(struct tracefs_instance pass:[*]_instance_, char pass:[*]_file_, int pass:[*]_psize_); + +-- + +DESCRIPTION +----------- +This set of APIs can be used to work with trace files in all trace instances. +Each of these APIs take an _instance_ argument, that can be NULL to act +on the top level instance. Otherwise, it acts on an instance created with +*tracefs_insance_create*(3) + +The _tracefs_file_exists()_ function checks if a file with _name_ exists in _instance_. + +The _tracefs_dir_exists()_ function checks if a directory with _name_ exists in _instance_. + +The _tracefs_instance_get_file()_ function returns the full path of the file +with given _name_ in _instance_. Note, it does not check if the file exists in +the instance. + +The _tracefs_instance_get_dir()_ function returns the full path of the directory +with given _name_ in _instance_. Note, it does not check if the directory exists +in the instance. + +The _tracefs_instance_file_write()_ function writes a string _str_ in a _file_ from +the given _instance_, without the terminating NULL character. + +The _tracefs_instance_file_read()_ function reads the content of a _file_ from +the given _instance_. + +RETURN VALUE +------------ +The _tracefs_file_exists()_ and _tracefs_dir_exists()_ functions return true if the +file / directory exist in the given instance or false if it does not exist. + +The _tracefs_instance_get_file()_ and _tracefs_instance_get_dir()_ functions return +a string or NULL in case of an error. The returned string must be freed with +_tracefs_put_tracing_file()_. + +The _tracefs_instance_file_write()_ function returns the number of written bytes, +or -1 in case of an error. + +The _tracefs_instance_file_read()_ function returns a pointer to a NULL terminated +string, read from the file, or NULL in case of an error. The returned string must +be freed with free(). + +EXAMPLE +------- +[source,c] +-- +#include + +struct tracefs_instance *inst = tracefs_instance_create("foo"); + if (!inst) { + /* Error creating a new trace instance */ + ... + } + + if (tracefs_file_exists(inst,"trace_clock")) { + /* The instance foo supports trace clock */ + char *path, *clock; + int size; + + path = = tracefs_instance_get_file(inst, "trace_clock") + if (!path) { + /* Error getting the path to trace_clock file in instance foo */ + ... + } + ... + tracefs_put_tracing_file(path); + + clock = tracefs_instance_file_read(inst, "trace_clock", &size); + if (!clock) { + /* Failed to read trace_clock file in instance foo */ + ... + } + ... + free(clock); + + if (tracefs_instance_file_write(inst, "trace_clock", "global") != strlen("global")) { + /* Failed to set gloabl trace clock in instance foo */ + ... + } + } else { + /* The instance foo does not support trace clock */ + } + + if (tracefs_dir_exists(inst,"options")) { + /* The instance foo supports trace options */ + char *path = tracefs_instance_get_file(inst, "options"); + if (!path) { + /* Error getting the path to options directory in instance foo */ + ... + } + + tracefs_put_tracing_file(path); + } else { + /* The instance foo does not support trace options */ + } + + ... + + if (tracefs_instance_is_new(inst)) + tracefs_instance_destroy(inst); + else + tracefs_instance_free(inst); +-- +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