From patchwork Mon Nov 8 08:03:55 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: 12607977 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 D5431C4332F for ; Mon, 8 Nov 2021 08:04:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B76FA61208 for ; Mon, 8 Nov 2021 08:04:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237450AbhKHIG4 (ORCPT ); Mon, 8 Nov 2021 03:06:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237433AbhKHIGz (ORCPT ); Mon, 8 Nov 2021 03:06:55 -0500 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64ED2C061570 for ; Mon, 8 Nov 2021 00:04:11 -0800 (PST) Received: by mail-ed1-x52f.google.com with SMTP id r12so58963877edt.6 for ; Mon, 08 Nov 2021 00:04:11 -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=XJdkg/DlWu5oe4f4IN0Mj44ojw6UTNspDKNrK2yAX6w=; b=XBhqH/19TxTw/ZBXKIoNbuS/NPT5V5Wpf44naJ7DhdHdVy39uu60fgcbs7IIsNJ4D9 EboWN7Dpj58Gs+Vn6e64uSoOjSjzE8bk9br/ZgX4j7o5kSq/ingJAe9N4zDB5VXuDNsZ 29QiCRygbTk+q4nComhn6vVcH2sSaMnYVWMvrYoJTGfN8PF7L7gZxRjMABpUdc1lS2QU 8LP9tNeYft3qZNQUJROAp8Ldvg0/bireyUtQjUiES+FyI298dKkp7EAWqbD/3ZxtScQC ykDHVBa2joSc9cK1+3jWP/72emhxJyQdfZSYmL7NFxXO6vIwnfTu9yhB4LOcDPAD3U64 TnSg== 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=XJdkg/DlWu5oe4f4IN0Mj44ojw6UTNspDKNrK2yAX6w=; b=apc89Td4B6BCQ/C0tL7l0qNjuW6ovZ6zdyntq8SvVthAglDuUaePoCJyRha2zcDfw8 0lA4O3O4V9aLpVvScNMwgOzp2Zcb8TTi+QEBySPyWpSAeG+UUugC5M3vvRhFpNRt4l5y Lc21eVF7kky/srfRiyzF27+knB3gyY4Qr3dP2brmgm3YKORM2IYN2aPpqwjwka4FFFsI r5rfz+lJQdPLkgS1ge3+ufrgnDwXv348I45qqy7XvGqIKf9peiCWTNYZeMn418ZBFe3r JdTq9wFJSEgGphbkKJ/H8oo7N1Fmz4Sx1H7olIVoYb7p1Gf32QNKB8kjUQqPnO0IZrHs gfXg== X-Gm-Message-State: AOAM532XMnYxf1bqRbLEtLd/waH4LioWM4QQruHH0yVJNkFYmEmUtECa 5k/+JaFH4dVXUvEyGktBFhQ= X-Google-Smtp-Source: ABdhPJyOusrwH1OMSJD26ovBBSNKVI12oofMfUsex/7Q/kTmw4fDBsv1zzqcM33ITn7+Vq/MKMxS/w== X-Received: by 2002:a17:907:6eaa:: with SMTP id sh42mr87645459ejc.556.1636358649929; Mon, 08 Nov 2021 00:04:09 -0800 (PST) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id mp5sm7962309ejc.68.2021.11.08.00.04.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Nov 2021 00:04:09 -0800 (PST) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org, y.karadz@gmail.com Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v6 03/12] libtracefs: Remove redundant kprobes APIs Date: Mon, 8 Nov 2021 10:03:55 +0200 Message-Id: <20211108080404.55814-4-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 The newly introduced set of APIs tracefs_dynevent_...() can be used to manage kprobes. These legacy APIs are removed as redundant: tracefs_kprobe_clear_all(); tracefs_kprobe_clear_probe(); tracefs_get_kprobes() tracefs_kprobe_info() There is one functionality, missing in the new clear API - clearing all dynamic events from specific system only. If this is needed, tracefs_dynevent_destroy() can be extended with that use case. Signed-off-by: Tzvetomir Stoyanov (VMware) --- include/tracefs.h | 11 -- src/tracefs-kprobes.c | 370 ------------------------------------------ 2 files changed, 381 deletions(-) diff --git a/include/tracefs.h b/include/tracefs.h index dfd9b51..25d9e9a 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -261,12 +261,6 @@ enum tracefs_dynevent_type tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system, char **event, char **prefix, char **addr, char **format); -enum tracefs_kprobe_type { - TRACEFS_ALL_KPROBES, - TRACEFS_KPROBE, - TRACEFS_KRETPROBE, -}; - struct tracefs_dynevent * tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format); struct tracefs_dynevent * @@ -276,11 +270,6 @@ 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, const char *addr, const char *format); -char **tracefs_get_kprobes(enum tracefs_kprobe_type type); -enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event, - char **type, char **addr, char **format); -int tracefs_kprobe_clear_all(bool force); -int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force); enum tracefs_hist_key_type { TRACEFS_HIST_KEY_NORMAL = 0, diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c index b9aeb9d..3f46b8d 100644 --- a/src/tracefs-kprobes.c +++ b/src/tracefs-kprobes.c @@ -213,373 +213,3 @@ int tracefs_kretprobe_raw(const char *system, const char *event, { return insert_kprobe("r", system, event, addr, format); } - -/* - * Helper function to parse kprobes. - * @content: The content of kprobe_events on the first iteration. - * NULL on next iterations. - * @saveptr: Same as saveptr for strtok_r - * @type: Where to store the type (before ':') - * @system: Store the system of the kprobe (NULL to have event contain - * both system and event, as in "kprobes/myprobe"). - * @event: Where to store the event. - * @addr: Where to store the addr (may be NULL to ignore) - * @format: Where to store the format (may be NULL to ignore) - */ -static int parse_kprobe(char *content, char **saveptr, - char **type, char **system, char **event, - char **addr, char **format) -{ - char *p; - - p = strtok_r(content, ":", saveptr); - if (!p) - return 1; /* eof */ - *type = p; - - if (system) { - p = strtok_r(NULL, "/", saveptr); - if (!p) - return -1; - *system = p; - } - - p = strtok_r(NULL, " ", saveptr); - if (!p) - return -1; - *event = p; - - if (addr || format) { - p = strtok_r(NULL, " ", saveptr); - if (!p) - return -1; - if (addr) - *addr = p; - } - - p = strtok_r(NULL, "\n", saveptr); - if (!p) - return -1; - if (format) - *format = p; - - return 0; -} - -/** - * tracefs_get_kprobes - return a list kprobes (by group/event name) - * @type: The type of kprobes to return. - * - * If @type is TRACEFS_ALL_KPROBES all kprobes in the kprobe_events - * are returned. Otherwise if it is TRACEFS_KPROBE, then only - * normal kprobes (p:) are returned, or if type is TRACEFS_KRETPROBE - * then only kretprobes (r:) are returned. - * - * Returns a list of strings that contain the kprobes that exist - * in the kprobe_events files. The strings returned are in the - * "group/event" format. - * The list must be freed with tracefs_list_free(). - * If there are no kprobes, a list is still returned, but it contains - * only a NULL pointer. - * On error, NULL is returned. - */ -char **tracefs_get_kprobes(enum tracefs_kprobe_type type) -{ - char **list = NULL; - char *content; - char *saveptr; - char *event; - char *ktype; - int ret; - - errno = 0; - content = tracefs_instance_file_read(NULL, KPROBE_EVENTS, NULL); - if (!content) { - if (errno) - return NULL; - /* content is NULL on empty file, return an empty list */ - return trace_list_create_empty(); - } - - ret = parse_kprobe(content, &saveptr, &ktype, NULL, &event, NULL, NULL); - - while (!ret) { - char **tmp; - - if (type != TRACEFS_ALL_KPROBES) { - switch (*ktype) { - case 'p': - if (type != TRACEFS_KPROBE) - goto next; - break; - case 'r': - if (type != TRACEFS_KRETPROBE) - goto next; - break; - default: - goto next; - } - } - - tmp = tracefs_list_add(list, event); - if (!tmp) - goto fail; - list = tmp; - next: - ret = parse_kprobe(NULL, &saveptr, &ktype, NULL, &event, NULL, NULL); - } - - if (!list) - list = trace_list_create_empty(); - out: - free(content); - return list; - fail: - tracefs_list_free(list); - list = NULL; - goto out; -} - -/** - * tracefs_kprobe_info - return the type of kprobe specified. - * @group: The group the kprobe is in (NULL for the default "kprobes") - * @event: The name of the kprobe to find. - * @type: String to return kprobe type (before ':') NULL to ignore. - * @addr: String to return address kprobe is attached to. NULL to ignore. - * @format: String to return kprobe format. NULL to ignore. - * - * If @type, @addr, or @format is non NULL, then the returned string - * must be freed with free(). They will also be set to NULL, and - * even on error, they may contain strings to be freed. If they are - * not NULL, then they still need to be freed. - * - * Returns TRACEFS_ALL_KPROBES if an error occurs or the kprobe is not found, - * or the probe is of an unknown type. - * TRACEFS_KPROBE if the type of kprobe found is a normal kprobe. - * TRACEFS_KRETPROBE if the type of kprobe found is a kretprobe. - */ -enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event, - char **type, char **addr, char **format) -{ - enum tracefs_kprobe_type rtype = TRACEFS_ALL_KPROBES; - char *saveptr; - char *content; - char *system; - char *probe; - char *ktype; - char *kaddr; - char *kfmt; - int ret; - - if (!group) - group = KPROBE_DEFAULT_GROUP; - - if (type) - *type = NULL; - if (addr) - *addr = NULL; - if (format) - *format = NULL; - - content = tracefs_instance_file_read(NULL, KPROBE_EVENTS, NULL); - if (!content) - return rtype; - - ret = parse_kprobe(content, &saveptr, &ktype, &system, &probe, - &kaddr, &kfmt); - - while (!ret) { - - if (!strcmp(system, group) && !strcmp(probe, event)) { - if (type) - *type = strdup(ktype); - if (addr) - *addr = strdup(kaddr); - if (format) - *format = strdup(kfmt); - - switch (*ktype) { - case 'p': rtype = TRACEFS_KPROBE; break; - case 'r': rtype = TRACEFS_KRETPROBE; break; - } - break; - } - ret = parse_kprobe(NULL, &saveptr, &ktype, &system, &probe, - &kaddr, &kfmt); - } - free(content); - return rtype; -} - -static void disable_events(const char *system, const char *event, - char **list) -{ - struct tracefs_instance *instance; - int i; - - /* - * Note, this will not fail even on error. - * That is because even if something fails, it may still - * work enough to clear the kprobes. If that's the case - * the clearing after the loop will succeed and the function - * is a success, even though other parts had failed. If - * one of the kprobe events is enabled in one of the - * instances that fail, then the clearing will fail too - * and the function will return an error. - */ - - tracefs_event_disable(NULL, system, event); - /* No need to test results */ - - if (!list) - return; - - for (i = 0; list[i]; i++) { - instance = tracefs_instance_alloc(NULL, list[i]); - /* If this fails, try the next one */ - if (!instance) - continue; - tracefs_event_disable(instance, system, event); - tracefs_instance_free(instance); - } - return; -} - -static int clear_kprobe(const char *system, const char *event) -{ - /* '-' + ':' + '/' + '\n' + '\0' = 5 bytes */ - int len = strlen(system) + strlen(event) + 5; - char content[len]; - - sprintf(content, "-:%s/%s", system, event); - return tracefs_instance_file_append(NULL, KPROBE_EVENTS, content); -} - -static int kprobe_clear_probes(const char *group, bool force) -{ - char **instance_list; - char **kprobe_list; - char *saveptr; - char *system; - char *kprobe; - char *event; - int ret; - int i; - - kprobe_list = tracefs_get_kprobes(TRACEFS_ALL_KPROBES); - if (!kprobe_list) - return -1; - - instance_list = tracefs_instances(NULL); - /* - * Even if the above failed and instance_list is NULL, - * keep going, as the enabled event may simply be in the - * top level. - */ - - /* - * If a system is defined, the default is to pass unless - * an event fails to be removed. If a system is not defined, - * the default is to fail, unless all are removed. - */ - ret = group ? 0 : -1; - - for (i = 0; kprobe_list[i]; i++) { - kprobe = kprobe_list[i]; - - system = strtok_r(kprobe, "/", &saveptr); - if (!system) - goto out; - - event = strtok_r(NULL," ", &saveptr); - if (!event) - goto out; - - /* Skip if this does not match a given system */ - if (group && strcmp(system, group) != 0) - continue; - - if (force) - disable_events(system, event, instance_list); - - if (group) { - ret = clear_kprobe(system, event); - if (ret < 0) - goto out; - } else { - ret = tracefs_instance_file_clear(NULL, KPROBE_EVENTS); - /* On success stop the loop */ - if (!ret) - goto out; - } - - /* Set the default for whether a system is defined or not */ - ret = group ? 0 : -1; - } - out: - tracefs_list_free(instance_list); - tracefs_list_free(kprobe_list); - return ret; -} - -/** - * tracefs_kprobe_clear_all - clear kprobe events - * @force: Will attempt to disable all kprobe events and clear them - * - * Will remove all defined kprobe events. If any of them are enabled, - * and @force is not set, then it will error with -1 and errno to be - * EBUSY. If @force is set, then it will attempt to disable all the kprobe - * events in all instances, and try again. - * - * Returns zero on success, -1 otherwise. - */ -int tracefs_kprobe_clear_all(bool force) -{ - 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); -} - -/** - * tracefs_kprobe_clear_all - clear kprobe events - * @system: System to clear (NULL means default) - * @event: Name of probe to clear in system (NULL for all probes in system) - * @force: Will attempt to disable all kprobe events and clear them - * - * Will remove the kprobes that match the @system and @event. If @system - * is NULL, then "kprobes" is used and will ignore all other system - * groups of kprobes. The @event is NULL then all events under the given - * @system are removed, otherwise only the event that matches. - * - * Returns zero on success, -1 otherwise. - */ -int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force) -{ - char **instance_list; - int ret; - - if (!system) - system = "kprobes"; - - if (!event) - return kprobe_clear_probes(system, 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(system, event, instance_list); - tracefs_list_free(instance_list); - } - - ret = clear_kprobe(system, event); - - return ret < 0 ? -1 : 0; -}