From patchwork Fri Nov 5 12:16:14 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: 12604553 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 66DC2C433F5 for ; Fri, 5 Nov 2021 12:16:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E76061262 for ; Fri, 5 Nov 2021 12:16:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230317AbhKEMTK (ORCPT ); Fri, 5 Nov 2021 08:19:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229500AbhKEMTJ (ORCPT ); Fri, 5 Nov 2021 08:19:09 -0400 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFC37C061714 for ; Fri, 5 Nov 2021 05:16:29 -0700 (PDT) Received: by mail-wr1-x42e.google.com with SMTP id c4so13388676wrd.9 for ; Fri, 05 Nov 2021 05:16:29 -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=g5y4JKxCW95q80MrAIv4cs6zp/FN3hiMfsAH+/jv0vI=; b=ArL6OSdi+veAi5X5WiLWl/hzrANiYn0h9mt4QCkHdqsev6mYSh15yH0V5yeLexMxVR NnFYyyqdLc/uBUMrZom941qXCKahOq6m4ttsTd3P7q+JQYINs48IciK988A6apw3Noiz eQrdWWWHVTDHbvSJtqwGrv7DfFOa2Ca70YMZEtHp7ymyAV2/j9LN2D2dxwW06cQ+Lk2b 1Jsm8EUcwNAvhZsBrPxvmFxhcV1XsMGXOPam9rCsnt8pcfbhv4qnCFWdMVWc3nQLnTzZ qsWANlB3zPlzyTuY5UBC1pb/qLhwFv5lO4Yvmc3JqJtaBdMUuWiBYdfOSFYbgdp/MW2Y WIZw== 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=g5y4JKxCW95q80MrAIv4cs6zp/FN3hiMfsAH+/jv0vI=; b=RYeRLlLDQ4xzlsApvwPol6/qHvyA1+JA2WUkgJdNFVT8tXjdSwKfOZFIG2zecsMUKk uriDorUmZyCRJ7xyWBdqsECh1sKXmVOuSvkQgU6ndCsE1KxkVKk0TdfnuB5pBZNgon86 lNmDaQ7lnCmN7TgW+/p6WhZfGIUO3wjKMcEWNFEppJIEiNwWSH86nWP87P4nTWcgb00K /iTyZ0FkFTSF8ndcyujYurLwUN087Zh8AqItZQPX17eo9Jvd+tW50gliro2dOdSoBNSO ygCZTdpSO7iJrKNs5eBVbHY0n4UcIMEicJpiBtwbxSwqxM0C5ZjWTcoUe5/rCMcZXMFa ZprQ== X-Gm-Message-State: AOAM53137rLGgIFuH82aSTBTq4tmLZ1o+vWuhnEvaegRsJzgTyjAsi00 XcTbpa4Vr4Q9oVkI3Bwtd0s= X-Google-Smtp-Source: ABdhPJyUMxd5eHShu+UW68joo1m1Muw1UDN+KbpomeD6mQKGFF6LIeUR57U8OsOdQSALEq9OA+7HGg== X-Received: by 2002:adf:ec90:: with SMTP id z16mr47021171wrn.247.1636114588474; Fri, 05 Nov 2021 05:16:28 -0700 (PDT) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id x13sm7936531wrr.47.2021.11.05.05.16.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Nov 2021 05:16:27 -0700 (PDT) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org, y.karadz@gmail.com Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v5 02/12] libtracefs: New APIs for kprobe allocation Date: Fri, 5 Nov 2021 14:16:14 +0200 Message-Id: <20211105121624.398717-3-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211105121624.398717-1-tz.stoyanov@gmail.com> References: <20211105121624.398717-1-tz.stoyanov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org In order to be consistent with the other APIs, new APIs for kprobe allocation are introduced: tracefs_kprobe_alloc(); tracefs_kretprobe_alloc(); These APIs allocate new kpobe dynamic event, that can be used with tracefs_dynevent_... set of APIs. Signed-off-by: Tzvetomir Stoyanov (VMware) --- include/tracefs.h | 5 ++ src/tracefs-kprobes.c | 109 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 114 insertions(+) diff --git a/include/tracefs.h b/include/tracefs.h index eceb1f5..dfd9b51 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -267,6 +267,11 @@ enum tracefs_kprobe_type { TRACEFS_KRETPROBE, }; +struct tracefs_dynevent * +tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format); +struct tracefs_dynevent * +tracefs_kretprobe_alloc(const char *system, const char *event, + const char *addr, const char *format, unsigned int max); int tracefs_kprobe_raw(const char *system, const char *event, const char *addr, const char *format); int tracefs_kretprobe_raw(const char *system, const char *event, diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c index 6fdd8f9..b9aeb9d 100644 --- a/src/tracefs-kprobes.c +++ b/src/tracefs-kprobes.c @@ -20,6 +20,115 @@ #define KPROBE_EVENTS "kprobe_events" #define KPROBE_DEFAULT_GROUP "kprobes" +static struct tracefs_dynevent * +kprobe_alloc(enum tracefs_dynevent_type type, const char *system, const char *event, + const char *addr, const char *format) +{ + struct tracefs_dynevent *kp; + const char *sys = system; + const char *ename = event; + char *tmp; + + if (!addr) { + errno = EBADMSG; + return NULL; + } + if (!sys) + sys = KPROBE_DEFAULT_GROUP; + + if (!event) { + ename = strdup(addr); + if (!ename) + return NULL; + tmp = strchr(ename, ':'); + if (tmp) + *tmp = '\0'; + } + + kp = dynevent_alloc(type, sys, ename, addr, format); + if (!event) + free((char *)ename); + + return kp; +} + +/** + * tracefs_kprobe_alloc - Allocate new kprobe + * @system: The system name (NULL for the default kprobes) + * @event: The event to create (NULL to use @addr for the event) + * @addr: The function and offset (or address) to insert the probe + * @format: The format string to define the probe. + * + * Allocate a kprobe context that 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 + * + * The kprobe is not created in the system. + * + * Return a pointer to a kprobe context on success, or NULL on error. + * The returned pointer must be freed with tracefs_dynevent_free() + * + * errno will be set to EBADMSG if addr is NULL. + */ +struct tracefs_dynevent * +tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format) + +{ + return kprobe_alloc(TRACEFS_DYNEVENT_KPROBE, system, event, addr, format); +} + +/** + * tracefs_kretprobe_alloc - Allocate new kretprobe + * @system: The system name (NULL for the default kprobes) + * @event: The event to create (NULL to use @addr for the event) + * @addr: The function and offset (or address) to insert the retprobe + * @format: The format string to define the retprobe. + * @max: Maximum number of instances of the specified function that + * can be probed simultaneously, or 0 for the default value. + * + * Allocate a kretprobe that 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 raw format + * of the kprobe. See the Linux documentation file under: + * Documentation/trace/kprobetrace.rst + * The kretprobe is not created in the system. + * + * Return a pointer to a kprobe context on success, or NULL on error. + * The returned pointer must be freed with tracefs_dynevent_free() + * + * errno will be set to EBADMSG if addr is NULL. + */ +struct tracefs_dynevent * +tracefs_kretprobe_alloc(const char *system, const char *event, + const char *addr, const char *format, unsigned int max) +{ + struct tracefs_dynevent *kp; + int ret; + + kp = kprobe_alloc(TRACEFS_DYNEVENT_KRETPROBE, system, event, addr, format); + if (!kp) + return NULL; + + if (!max) + return kp; + + free(kp->prefix); + kp->prefix = NULL; + ret = asprintf(&kp->prefix, "r%d:", max); + if (ret < 0) + goto error; + + return kp; +error: + tracefs_dynevent_free(kp); + return NULL; +} + static int insert_kprobe(const char *type, const char *system, const char *event, const char *addr, const char *format)