From patchwork Mon Nov 8 08:04:02 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: 12607991 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 21A6BC433FE for ; Mon, 8 Nov 2021 08:04:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AEFB6125F for ; Mon, 8 Nov 2021 08:04:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237469AbhKHIHC (ORCPT ); Mon, 8 Nov 2021 03:07:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237461AbhKHIHC (ORCPT ); Mon, 8 Nov 2021 03:07:02 -0500 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61FADC061570 for ; Mon, 8 Nov 2021 00:04:18 -0800 (PST) Received: by mail-ed1-x536.google.com with SMTP id x15so27689138edv.1 for ; Mon, 08 Nov 2021 00:04:18 -0800 (PST) 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=XJvnvRjQV5WIu4vp2/wBSqNpB3fDsNCwh2Y+3NXJ7Ao=; b=jfuW9NGm14hS1bW/HYuNcafXnEaZXlQ7acAS6sp3uNiDqa0xqYyUoH9JxTNdVn/yve nQt92UA0Z9VEjAZfTGzik8qMVwIPV7lLGF1UvPmxBwUtyzGYxY9CwMc/8dFIc651ZvY1 oKNUNZaKYNODMICwK5d7zDQdCPsimU3NTKuS+Qcmchcpee/1nQQuKo0rv1zt269RiYIm FwFxUYD3+5EBlUDgpmJ5iKSung2SMl7PsVqVq5losy+ZyDbjPp0VSfxBCMblRa9Q/6Pj aduQaRGOcTPbVne3lX5qhLNBG1qQe7j48JexbfyEdKCvYP28Tm7QqsX8mN98orsTMaGD S9aQ== 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=XJvnvRjQV5WIu4vp2/wBSqNpB3fDsNCwh2Y+3NXJ7Ao=; b=zFVDWrpwlTcXw7PI2Xi4QUKFs6O9gAEnEa3MVL8/tC90G4UCuKOO23CNXrHZG6OvxB XqPtdA0AoOZ6cQf5cyJiD89WYhPh171AIjU06WI8IeevsgexVaMf11eUulGWVwSix/QY o2p1D5izxMHRWPLmDVKNZx0dmWAr5CrNcOaYzcMwjTbJZm4F+91JeaFQlRu8MpsWj3vd Qgb+VHA9tjQXi3RpGp4ka8lffOle4xt037gMACTjGapQuXDJgCaJxR+t486tTG0Xj2DO 5hLtSll/ie4ATVq7dkCy163IyR5ZLrJnPjbcBnI3ARHYc3iOPSXysOlAqNU6W4yHfDHf nX4w== X-Gm-Message-State: AOAM531aIEIoZwayxZflrRZK4ti4e5x+AIy55cYdFKqp1l/I6a1xZ8wH /NOgj5RoenizJ6c22p8eHNrxevxt1zFbHw== X-Google-Smtp-Source: ABdhPJxnjPcTokHUACLdoooVP/8btbEjTpRoulfY5Y+69c5Qu/5K1OgjO31zOMCXMP0EmCxjsX5eTQ== X-Received: by 2002:a50:e141:: with SMTP id i1mr105557567edl.157.1636358656929; Mon, 08 Nov 2021 00:04:16 -0800 (PST) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id mp5sm7962309ejc.68.2021.11.08.00.04.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Nov 2021 00:04:16 -0800 (PST) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org, y.karadz@gmail.com Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v6 10/12] libtracefs: Update kprobes man pages Date: Mon, 8 Nov 2021 10:04:02 +0200 Message-Id: <20211108080404.55814-11-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211108080404.55814-1-tz.stoyanov@gmail.com> References: <20211108080404.55814-1-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 | 94 +++++++++++----------------- Documentation/libtracefs.txt | 6 ++ 2 files changed, 41 insertions(+), 59 deletions(-) diff --git a/Documentation/libtracefs-kprobes.txt b/Documentation/libtracefs-kprobes.txt index c10576e..4a4bf01 100644 --- a/Documentation/libtracefs-kprobes.txt +++ b/Documentation/libtracefs-kprobes.txt @@ -3,7 +3,8 @@ 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_raw, tracefs_kretprobe_raw - +Allocate, get, and create kprobes SYNOPSIS -------- @@ -11,18 +12,30 @@ 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_, unsigned int _max_); +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) and have the name of +_event_ (or _addr_ if _event_ is NULL). The kprobe 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_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 +49,17 @@ 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_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. +*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_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. +The *tracefs_kprobe_alloc*() and *tracefs_kretprobe_alloc*() APIs return a pointer to an allocated +tracefs_dynevent structure, describing the probe. This pointer must be freed by +*tracefs_dynevent_free*(3). Note, this only allocates a descriptor representing the kprobe. It does +not modify the running system. ERRORS ------ @@ -96,9 +71,10 @@ 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 +193,7 @@ int main (int argc, char **argv, char **env) exit(-1); } - tracefs_kprobe_clear_probe(mykprobe, NULL, true); + tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_KPROBE | TRACEFS_DYNEVENT_KRETPROBE, true); kprobe_create("open", "do_sys_openat2", "file=+0($arg2):ustring flags=+0($arg3):x64 mode=+8($arg3):x64\n"); @@ -247,7 +223,7 @@ 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_dynevent_destroy_all(TRACEFS_DYNEVENT_KPROBE | TRACEFS_DYNEVENT_KRETPROBE, true); tracefs_instance_destroy(instance); tep_free(tep); @@ -293,5 +269,5 @@ 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..430d02e 100644 --- a/Documentation/libtracefs.txt +++ b/Documentation/libtracefs.txt @@ -63,6 +63,12 @@ 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_, unsigned int _max_); + 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