From patchwork Thu Nov 4 11:10:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Tzvetomir Stoyanov (VMware)" X-Patchwork-Id: 12602907 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F03BC433FE for ; Thu, 4 Nov 2021 11:11:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2573A611EE for ; Thu, 4 Nov 2021 11:11:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231420AbhKDLNj (ORCPT ); Thu, 4 Nov 2021 07:13:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54416 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231440AbhKDLNi (ORCPT ); Thu, 4 Nov 2021 07:13:38 -0400 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60EB7C06127A for ; Thu, 4 Nov 2021 04:11:00 -0700 (PDT) Received: by mail-wr1-x434.google.com with SMTP id b12so8001569wrh.4 for ; Thu, 04 Nov 2021 04:11:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=X58UzyB0GLSm23F3DovGKA2tUpNpMQEd/EUrBeLPFWg=; b=dORHV5vkH+HER7tqC0Q7vQMVDL6U5mQpQAi5l2jmPYZryoG1d9pd9fgvEd8wCoY5rW /XA6lG4pnb0qp0YdC9n8qYbUVW16EpYm4/9pTzeuVyirIFsGFMmsCqApE1pjQVpeT4h7 sn8iODGrt1ovzu6MFfq8Q1362bQcXW7dvGke4PigVFRnmQmT80AULFGLlBZZYi313EtE W8ii0fYAAMLH81zIUycwkXiEYJ12pcWukn6hEJhjTrG6hxPmMCKKWO0aSVESqZCHP0at L7/uGOLBi5e3EIV6P1ZxcAj+r45Y3gF1Tl3cWy+X90QM/OHa+4m1LQfXMKcx2xRa00Hw T1Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=X58UzyB0GLSm23F3DovGKA2tUpNpMQEd/EUrBeLPFWg=; b=qPbmOrEej0SAP2pdiiEnHr6OvST0pDpoJC3nF1OxUiy3sJXeXCrM2BTegC5NQnsPOD ckTsE80exCWBFxjtXE7FQYtcUYqsIqMttvUwQnjtUfu8X/bYFsZAQTkM9MDa3N/RDVvB 8ktyocOreFrYeRiKQXUwuF7ji3Gl/xyokg4SW0NUrSysmLhxFJYk4jN+vlfS0WA6pQZp JM+UotG5kgQtjjO4HcRe8McK4zZBPduKdkiaRDq0lzAJDalsifAMJGm1Crg5EfVDhb92 PvO1q/kVUW+GVYaH522ScT+srnSUEcoK5TTdrJb3zjve8oG9jpBwO5chIxZRUEOIPwbT 66kQ== X-Gm-Message-State: AOAM533WcafG1XsknnGP4KHnOAHKe9IjBKiiWL7hJPClazuZQ7cVKDC7 BxNLhP1RIMqImeQVkKPELGJwmhZfjlru6g== X-Google-Smtp-Source: ABdhPJwEnmP8JJ0KckUhp9qMSQrvRPtm169Ph6sm8uqBMsm0Vkwncqy/cccuUVzpoSJpoSXGnc4GYg== X-Received: by 2002:a05:6000:252:: with SMTP id m18mr41620629wrz.117.1636024258848; Thu, 04 Nov 2021 04:10:58 -0700 (PDT) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id l18sm5080843wrt.81.2021.11.04.04.10.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Nov 2021 04:10:58 -0700 (PDT) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org, y.karadz@gmail.com Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v4 09/10] libtracefs: Update kprobes man pages Date: Thu, 4 Nov 2021 13:10:46 +0200 Message-Id: <20211104111047.302660-10-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211104111047.302660-1-tz.stoyanov@gmail.com> References: <20211104111047.302660-1-tz.stoyanov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org As there are a lot of changes in the libtracefs kprobes APIs, the documentation of the library should be updated. Signed-off-by: Tzvetomir Stoyanov (VMware) --- Documentation/libtracefs-kprobes.txt | 111 +++++++++++++-------------- Documentation/libtracefs.txt | 7 ++ 2 files changed, 60 insertions(+), 58 deletions(-) diff --git a/Documentation/libtracefs-kprobes.txt b/Documentation/libtracefs-kprobes.txt index c10576e..fedac96 100644 --- a/Documentation/libtracefs-kprobes.txt +++ b/Documentation/libtracefs-kprobes.txt @@ -3,7 +3,9 @@ libtracefs(3) NAME ---- -tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_get_kprobes, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes +tracefs_kprobe_alloc, tracefs_kretprobe_alloc, tracefs_kprobe_info, +tracefs_kprobe_raw, tracefs_kretprobe_raw - Allocate, get, and create kprobes + SYNOPSIS -------- @@ -11,18 +13,44 @@ SYNOPSIS -- *#include * -int tracefs_kprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format); -int tracefs_kretprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format); -char pass:[*]pass:[*]tracefs_get_kprobes(enum tracefs_kprobe_type type); -enum tracefs_kprobe_type tracefs_kprobe_info(const char pass:[*]group, const char pass:[*]event, - char pass:[*]pass:[*]type, char pass:[*]pass:[*]addr, char pass:[*]pass:[*]format); -enum tracefs_kprobe_type tracefs_kprobe_type(const char pass:[*]group, const char pass:[*]event) -int tracefs_kprobe_clear_all(bool force); -int tracefs_kprobe_clear_probe(const char pass:[*]system, const char pass:[*]event, bool force); +struct tracefs_dynevent pass:[*] +*tracefs_kprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_, + const char pass:[*]_addr_, const char pass:[*]_format_); +struct tracefs_dynevent pass:[*] +*tracefs_kretprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_, + const char pass:[*]_addr_, const char pass:[*]_format_, int _max_); +enum tracefs_dynevent_type *tracefs_kprobe_info*(struct tracefs_dynevent pass:[*]_kprobe_, + char pass:[*]pass:[*]_system_, char pass:[*]pass:[*]_event_, + char pass:[*]pass:[*]_prefix_, char pass:[*]pass:[*]_addr_, + char pass:[*]pass:[*]_format_); +int *tracefs_kprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_, + const char pass:[*]_addr_, const char pass:[*]_format_); +int *tracefs_kretprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_, + const char pass:[*]_addr_, const char pass:[*]_format_); -- DESCRIPTION ----------- +*tracefs_kprobe_alloc*() allocates a new kprobe context. The kbrobe is not configured in the system. +The new kprobe will be in the _system_ group (or kprobes if _system_ is NULL). Have the name of +_event_ (or _addr_ if _event_ is NULL). Will be inserted to _addr_ (function name, with or without +offset, or a address). And the _format_ will define the format of the kprobe. See the Linux +documentation file under: Documentation/trace/kprobetrace.rst + +*tracefs_kretprobe_alloc*() is the same as *tracefs_kprobe_alloc*, but allocates context for +kretprobe. It has one additional parameter, which is optional, _max_ - maxactive count. +See description of kretprobes in the Documentation/trace/kprobetrace.rst file. + +*tracefs_kprobe_info*() returns the type and information of a given _kprobe_. If any of the +_system_, _event_, _prefix_, _addr_ or _format_ arguments are not NULL, then strings are allocated +and returned back via these arguments. The _system_ and _event_ holds the system and the name of the +kprobe. If _prefix_ is non NULL, then it will hold an allocated string that holds the prefix portion +of the kprobe in the kprobe_events file (the content up to the ":", including it). Note that for +kretprobes, the max active count is encoded in the prefix srting. If _addr_ is non NULL, it will +hold the address or function that the kprobe is attached to. If _format_ is non NULL, it will hold +the format string of the kprobe. Note, that the content in _group_, _event_, _prefix_, _addr_, and +_format_ must be freed with free(3) if they are set. + *tracefs_kprobe_raw*() will create a kprobe event. If _system_ is NULL, then the default "kprobes" is used for the group (event system). Otherwise if _system_ is specified then the kprobe will be created under the group by that name. The @@ -36,55 +64,21 @@ document. creates a kretprobe instead of a kprobe. The difference is also described in the Linux kernel source in the Documentation/trace/kprobetrace.rst file. -*tracefs_get_kprobes*() returns an array of strings (char pass:[*]) that contain -the registered kprobes and kretprobes depending on the given _type_. If _type_ is -TRACEFS_ALL_KPROBES, then all kprobes found are returned. If _type_ is -TRACEFS_KPROBE, then only normal kprobes are returned. If _type_ is -TRACEFS_KRETPROBE, then only kretprobes are returned. -The names are in the "system/event" format. -That is, one string holds both the kprobe's name as well as the group it is -defined under. These strings are allocated and may be modified with the -*strtok*(3) and *strtok_r*(3) functions. The string returned must be freed with -*tracefs_list_free*(3). - -*tracefs_kprobe_info*() returns the type of the given kprobe. If _group_ is -NULL, then the default "kprobes" is used. If _type_ is non NULL, then it will -hold an allocated string that holds the type portion of the kprobe in the -kprobe_events file (the content before the ":"). If _addr_ is non NULL, it will -hold the address or function that the kprobe is attached to. If _format_ is non -NULL, it will hold the format string of the kprobe. Note, that the content in -_type_, _addr_, and _format_ must be freed with free(3) if they are set. Even -in the case of an error, as they may hold information of what caused the error. - -*tracefs_kprobe_clear_all*() will try to remove all kprobes that have been -registered. If the @force flag is set, it will then disable those kprobe events -if they are enabled and then try to clear the kprobes. - -*tracefs_kprobe_clear_probe*() will try to clear specified kprobes. If _system_ -is NULL, then it will only clear the default kprobes under the "kprobes" group. -If _event_ is NULL, it will clear all kprobes under the given _system_. If the -_force_ flag is set, then it will disable the given kprobe events before clearing -them. - RETURN VALUE ------------ -*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_clear_all*(), -and *tracefs_kprobe_clear_probe*() return 0 on success, or -1 on error. - -If a parsing error occurs on *tracefs_kprobe_raw*() or *tracefs_kretprobe_raw*() -then *tracefs_error_last*(3) may be used to retrieve the error message explaining -the parsing issue. +*tracefs_kprobe_raw*() and *tracefs_kretprobe_raw*() return 0 on success, or -1 on error. +If a parsing error occurs on *tracefs_kprobe_raw*() or *tracefs_kretprobe_raw*() then +*tracefs_error_last*(3) may be used to retrieve the error message explaining the parsing issue. -*tracefs_get_kprobes*() returns an allocate string list of allocated strings -on success that must be freed with *tracefs_list_free*(3) and returns -NULL on error. +The *tracefs_kprobe_alloc*() and *tracefs_kretprobe_alloc*() APIs return pointer to allocated +tracefs_dynevent structure, describing the probe. This pointer must be freed by +*tracefs_dynevent_free*(3). -*tracefs_kprobe_info*() returns the type of the given kprobe. It returns -TRACEFS_KPROBE for normal kprobes, TRACEFS_KRETPROBE for kretprobes, and -on error, or if the kprobe is not found TRACEFS_ALL_KPROBES is returned. -If _type_, _addr_, or _format_ are non NULL, they will contain allocated -strings that must be freed by free(3) even in the case of error. +*tracefs_kprobe_info*() returns the type of the given kprobe. It returns TRACEFS_DYNEVENT_KPROBE for +normal kprobes, TRACEFS_DYNEVENT_KRETPROBE for kretprobes or TRACEFS_DYNEVENT_MAX on error. +If _system_, _event_, _prefix_, _addr_, or _format_ are non NULL, they will contain allocated +strings that must be freed by free(3). ERRORS ------ @@ -96,9 +90,10 @@ The following errors are for all the above calls: *ENOMEM* Memory allocation error. -*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*() can fail with the following errors: +*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_alloc*(), +and *tracefs_kretprobe_alloc*() can fail with the following errors: -*EBADMSG* Either _addr_ or _format_ are NULL. +*EBADMSG* if _addr_ is NULL. *EINVAL* Most likely a parsing error occurred (use *tracefs_error_last*(3) to possibly see what that error was). @@ -217,7 +212,7 @@ int main (int argc, char **argv, char **env) exit(-1); } - tracefs_kprobe_clear_probe(mykprobe, NULL, true); + tracefs_kprobe_destroy(NULL, true); kprobe_create("open", "do_sys_openat2", "file=+0($arg2):ustring flags=+0($arg3):x64 mode=+8($arg3):x64\n"); @@ -247,7 +242,7 @@ int main (int argc, char **argv, char **env) } while (waitpid(pid, NULL, WNOHANG) != pid); /* Will disable the events */ - tracefs_kprobe_clear_probe(mykprobe, NULL, true); + tracefs_kprobe_destroy(NULL, true); tracefs_instance_destroy(instance); tep_free(tep); @@ -293,5 +288,5 @@ https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/ COPYING ------- -Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under +Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL). diff --git a/Documentation/libtracefs.txt b/Documentation/libtracefs.txt index 2c9eabd..f679002 100644 --- a/Documentation/libtracefs.txt +++ b/Documentation/libtracefs.txt @@ -63,6 +63,13 @@ Writing data in the trace buffer: Control library logs: int *tracefs_set_loglevel*(enum tep_loglevel _level_); + +Kprobes and Kretprobes: + struct tracefs_dynevent pass:[*] *tracefs_kprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_); + struct tracefs_dynevent pass:[*] *tracefs_kretprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_, int _max_); + enum tracefs_kprobe_type *tracefs_kprobe_info*(struct tracefs_dynevent pass:[*]_kprobe_, char pass:[*]pass:[*]_system_, char pass:[*]pass:[*]_event_, char pass:[*]pass:[*]_prefix_, char pass:[*]pass:[*]_addr_, char pass:[*]pass:[*]_format_); + int *tracefs_kprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_); + int *tracefs_kretprobe_raw*(const char pass:[*]_system_, const char pass:[*]_event_, const char pass:[*]_addr_, const char pass:[*]_format_); -- DESCRIPTION