From patchwork Mon Nov 1 09:08:55 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: 12596163 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 AD190C433F5 for ; Mon, 1 Nov 2021 09:09:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93EFE610A2 for ; Mon, 1 Nov 2021 09:09:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231663AbhKAJLo (ORCPT ); Mon, 1 Nov 2021 05:11:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231223AbhKAJLo (ORCPT ); Mon, 1 Nov 2021 05:11:44 -0400 Received: from mail-ed1-x529.google.com (mail-ed1-x529.google.com [IPv6:2a00:1450:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BDDFC061764 for ; Mon, 1 Nov 2021 02:09:11 -0700 (PDT) Received: by mail-ed1-x529.google.com with SMTP id f8so40513132edy.4 for ; Mon, 01 Nov 2021 02:09:11 -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=EurvI2Ss2jj+0FFeY+TsOaNc1bjeg/+ms9WvczUT5Gs=; b=UT/N1bk3piEZa/F6hJdH2jhMrveS97ab9yzw6zbyDzz/oIkI4yq5QckZuw9snnc/eg BOKbN1dhm+s9IN2cUWtBucDbG6aB+wShT7YagebMbs0k3x6Khn8xRh1qvdbLb4waiPMG hGJrVOMgq/2gWDKKc/eX8kqOrb3IhngSCSKuBTFZA5Rxa2fjTxKYQNtEW0Rs+BcGsxUc vg/Be9Piz4Ol5SsmDjj7AoNz00Vx30AreyJ0PlZuodIbtVrQ8dlk6Kj3Xp6SnNj+R/VA iTC0Nx1BB5424HAQmgqo/sKCTYFDzF63wK1u17Poq2CYsldCcDguBFo3iK3YstV/X2Vh B6ww== 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=EurvI2Ss2jj+0FFeY+TsOaNc1bjeg/+ms9WvczUT5Gs=; b=oNGPicczD7TdipwtsJZmNsXgOSut/hlBsNC/xUBXZvIBGT1fHIxdKzbX/A0PP2yNXS x33ek0SGz00TMDH8r05xS6/j0CHh7qVjwdU/zXlqLF7WHRg/7WH+IVFcY/a9Sg4NtdnL jsFX/h2/J11Dq+H+BbDJIM7/+Vm76t6Q8NtlL72nQo7T4r3GpNw+I1WoAClUMJbdLDMs Z0mWjfyEWRlQDkAO+TVGOZZUxvf29hwyP5E44ytQuhuRNju7alm4YgjzQB+1r96xIjq+ nun0T67KZxrg0NWfH4YOfdhWqBsOKT27S3ghc4FK+wSOONiVrfzJWvdnxZBuZzuirZbt xZYg== X-Gm-Message-State: AOAM531DqauyIYI7HSAN781zyxPrjU5SDSbGImDik07mdioXNddIcD+f uEmIDxzLQjw89Ig9hufSQCc= X-Google-Smtp-Source: ABdhPJzEdpnpfEvG6DAZVfA51pi9jWQky4COKLFVR/d07budCnXBFwNw0A65aJD+K0+d7/drLBjNFQ== X-Received: by 2002:a05:6402:50ca:: with SMTP id h10mr8011194edb.277.1635757749988; Mon, 01 Nov 2021 02:09:09 -0700 (PDT) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id i8sm9873222edc.10.2021.11.01.02.09.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Nov 2021 02:09:09 -0700 (PDT) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org, y.karadz@gmail.com Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v2 03/12] libtracefs: New kprobes APIs Date: Mon, 1 Nov 2021 11:08:55 +0200 Message-Id: <20211101090904.81454-4-tz.stoyanov@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211101090904.81454-1-tz.stoyanov@gmail.com> References: <20211101090904.81454-1-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, a new set of kprobe APIs is introduced: tracefs_kprobe_alloc(); tracefs_kretprobe_alloc(); tracefs_kprobe_create(); tracefs_kprobe_destroy(); tracefs_kprobe_free(); These APIs work with kprobe context, represented by the tracefs_dynevent structure. Signed-off-by: Tzvetomir Stoyanov (VMware) --- include/tracefs.h | 8 ++ src/tracefs-kprobes.c | 168 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 176 insertions(+) diff --git a/include/tracefs.h b/include/tracefs.h index 4e721eb..85185ce 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -247,6 +247,14 @@ 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, int max); +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe); +int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force); +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe); 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 d4c5f9e..906f914 100644 --- a/src/tracefs-kprobes.c +++ b/src/tracefs-kprobes.c @@ -20,6 +20,134 @@ #define KPROBE_EVENTS "kprobe_events" #define KPROBE_DEFAULT_GROUP "kprobes" +static struct tracefs_dynevent * +kprobe_alloc(enum trace_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 context + * @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_kprobe_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(TRACE_DYNEVENT_KPROBE, system, event, addr, format); +} + +/** + * tracefs_kretprobe_alloc - Allocate new kretprobe context + * @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. + * + * 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_kprobe_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, int max) +{ + struct tracefs_dynevent *kp; + int ret; + + kp = kprobe_alloc(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format); + if (!kp) + return NULL; + if (max) { + free(kp->prefix); + kp->prefix = NULL; + ret = asprintf(&kp->prefix, "r%d:", max); + if (ret < 0) + goto error; + } + + return kp; +error: + dynevent_free(kp); + return NULL; +} + +/** + * tracefs_kprobe_create - Create a kprobe or kretprobe in the system + * @kprobe: Pointer to a kprobe context, describing the probe + * + * Return 0 on success, or -1 on error. + */ +int tracefs_kprobe_create(struct tracefs_dynevent *kprobe) +{ + return dynevent_create(kprobe); +} + +/** + * tracefs_kprobe_free - Free a kprobe context + * @kprobe: Pointer to a kprobe context + * + * The kprobe/kretprobe, described by this context, is not + * removed from the system by this API. It only frees the memory. + */ +void tracefs_kprobe_free(struct tracefs_dynevent *kprobe) +{ + dynevent_free(kprobe); +} + + static int insert_kprobe(const char *type, const char *system, const char *event, const char *addr, const char *format) @@ -474,3 +602,43 @@ int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force return ret < 0 ? -1 : 0; } + +/** + * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system + * @kprobe: A kprobe context, describing the kprobe that will be deleted. + * If NULL, all kprobes and kretprobes in the system will be deleted + * @force: Will attempt to disable all kprobe events and clear them + * + * The kprobe/kretprobe context is not freed by this API. + * It only removes the probe from the system. + * + * Return 0 on success, or -1 on error. + */ +int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force) +{ + char **instance_list; + int ret; + + if (!kprobe) { + if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0) + return 0; + if (!force) + return -1; + /* Attempt to disable all kprobe events */ + return kprobe_clear_probes(NULL, force); + } + + /* + * Since we know we are disabling a specific event, try + * to disable it first before clearing it. + */ + if (force) { + instance_list = tracefs_instances(NULL); + disable_events(kprobe->system, kprobe->event, instance_list); + tracefs_list_free(instance_list); + } + + ret = dynevent_destroy(kprobe); + + return ret < 0 ? -1 : 0; +}