From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00, DATE_IN_FUTURE_12_24,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 320D6C433E0 for ; Fri, 5 Mar 2021 11:21:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF7D465018 for ; Fri, 5 Mar 2021 11:20:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229528AbhCELU1 (ORCPT ); Fri, 5 Mar 2021 06:20:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229464AbhCELT7 (ORCPT ); Fri, 5 Mar 2021 06:19:59 -0500 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8D05C061574 for ; Fri, 5 Mar 2021 03:19:58 -0800 (PST) Received: by mail-pl1-x62c.google.com with SMTP id g20so1267541plo.2 for ; Fri, 05 Mar 2021 03:19:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=InTGYNTfaL4kjg4JYdOj9L+WtXl9SVBLxHl7IgJIOCE=; b=jIx5dR5RJ284bKlZBHqMZNdyKSGw/Mpx34xkqO5eCQHTgjDnsyyXf4Ug/wBmhzgA2O 2KW40XRJRBbi4/xdn4M5HekKW1tIZBNqY6b1RZMzB5MPiPvnBvO7J4dfItuQhHRxQjLH bQXz5VNnoiC5lW08oRHg8iajjanqxvQFbNr9GC4tCUrvLN+X7U2GnIYaETjOs1jC6gml 5kGd1FY8JEEND6jHA3FYm25+Qn33+lfPZwUBMPQefX+I6senqUdoag/HpXDN5uPQsduP Q+rXISSz4C++Ahut1vWb4kEohiR10VoSK7IU2xWzerTEOqaJZte8UbCVv+mn8WxCFhKF cPRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=InTGYNTfaL4kjg4JYdOj9L+WtXl9SVBLxHl7IgJIOCE=; b=RyTNGsyS/JK6LdDDeHvh+VcRwuwSdzhWasgRw1l1fEOO9lBubf4LpxyNGQ9vh/iM0K twMZeHjYaS5GNOb3HZ4M1usVRpBMqympVPIonFXa8BUEKvA3FMWIpQvQD2UhpQxVnLD4 3dnw8774af2T05Mt5pf0lcHbZYycB4A1oExS5y4cPCitj2/pV8ByaJyk0MrAhadc/fvr XeSuS0WPPMbHcwKPebfjQz5BBMHdSatcdzWssBwFCBERqLfZbx7U2QxheymO0ih05b7g Yuw3OzZDdIc1jbPtPhLRE4RDAALb8he2LrFFle80kfSJ309ffIoKjUsXEeRZvAFCSEwO 4eaw== X-Gm-Message-State: AOAM533DYLL0cki/TRp02dvEOXM0Qf0/3VD5MH/6IjKg64pZ7xVMfhp6 sVSuhLBzZyy4VZSTgD0Wc4M= X-Google-Smtp-Source: ABdhPJzi4TeODety4xxuOqGF7yYB13WoiKqXf4bohPjHQ3Wjy7Iu4NKOrjDtJac/uGc3f67aVjzKXQ== X-Received: by 2002:a17:90a:c594:: with SMTP id l20mr7084473pjt.163.1614943198436; Fri, 05 Mar 2021 03:19:58 -0800 (PST) Received: from localhost.localdomain ([45.118.75.3]) by smtp.gmail.com with ESMTPSA id k69sm2293881pfd.4.2021.03.05.03.19.56 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Mar 2021 03:19:57 -0800 (PST) From: Sameeruddin shaik To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org, Sameeruddin shaik Subject: [PATCH] libtracefs: An API to set the filtering of functions Date: Sat, 6 Mar 2021 16:50:25 +0530 Message-Id: <1615029625-9749-1-git-send-email-sameeruddin.shaik8@gmail.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org This new API will write the function filters into the set_ftrace_filter file. tracefs_function_filter() https://bugzilla.kernel.org/show_bug.cgi?id=210643 Signed-off-by: Sameeruddin shaik diff --git a/include/tracefs.h b/include/tracefs.h index f3eec62..2e5d3e3 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -50,6 +50,7 @@ int tracefs_trace_on(struct tracefs_instance *instance); int tracefs_trace_off(struct tracefs_instance *instance); int tracefs_trace_on_fd(int fd); int tracefs_trace_off_fd(int fd); +int tracefs_function_filter(struct tracefs_instance *instance, const char **filters, const char *module, bool reset, const char **errs); /** * tracefs_trace_on_get_fd - Get a file descriptor of "tracing_on" in given instance diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c index e2dfc7b..8311191 100644 --- a/src/tracefs-tools.c +++ b/src/tracefs-tools.c @@ -18,6 +18,7 @@ #include "tracefs-local.h" #define TRACE_CTRL "tracing_on" +#define TRACE_FILTER "set_ftrace_filter" static const char * const options_map[] = { "unknown", @@ -387,3 +388,90 @@ void tracefs_option_clear(struct tracefs_options_mask *options, enum tracefs_opt if (options && id > TRACEFS_OPTION_INVALID) options->mask &= ~(1ULL << (id - 1)); } + +static int controlled_write(const char *filter_path, const char **filters, const char *module, bool reset, const char **errs) +{ + int flags = reset ? O_TRUNC : O_APPEND; + int write_size; + char *each_str; + int ret = 0; + int j = 0; + int size; + int slen; + int fd; + int i; + + fd = open(filter_path, O_WRONLY | flags); + if (fd < 0) + return -1; + + for (i = 0; filters[i]; i++) { + slen = strlen(filters[i]); + if (!slen) + continue; + + if (module) + /* Adding 5 extra bytes for ":mod:"*/ + slen += strlen(module) + 5; + + /* Adding 2 extra byte for the space and '\0' at the end*/ + slen += 2; + each_str = calloc(1, slen); + if (!each_str) + return -1; + if (module) + write_size = snprintf(each_str, slen, "%s:mod:%s ", filters[i], module); + else + write_size = snprintf(each_str, slen, "%s ", filters[i]); + + size = write(fd, each_str, write_size); + /* compare written bytes and also compare the written bytes with difference of added 5 bytes to string for ":mod:"*/ + if ((size < write_size) && (size < (write_size - 5))) { + errs[j++] = filters[i]; + ret -= 1; + } + free(each_str); + } + errs[j] = NULL; + close(fd); + return ret; +} + +/** + * tracefs_function_filter - write to set_ftrace_filter file to trace particular functions + * @instance: ftrace instance, can be NULL for top tracing instance + * @filters: An array of function names ending with a NULL pointer + * @module: Module to be traced + * @reset: set to true to reset the file before applying the filter + * @errs: An Array of failed function names ending with a NULL pointer + * + * The @filters is an array of strings, where each string will be used to set + * a function or functions to be traced. + * + * If @reset is true, then all functions in the filter are cleared before + * adding functions from @filter. Otherwise, the functions set by @filter + * will be appended to the filter file + * + * The @errs is an array of strings, where each string is a failed function + * name + * + * returns -x (where x is number of failed filter srtings or it can be + * 1 for general errors), or 0 if there are no errors. + */ +int tracefs_function_filter(struct tracefs_instance *instance, const char **filters, const char *module, bool reset, const char **errs) +{ + char *ftrace_filter_path; + int ret = 0; + + if (!filters) + return -1; + + ftrace_filter_path = tracefs_instance_get_file(instance, TRACE_FILTER); + if (!ftrace_filter_path) + goto out; + + ret = controlled_write(ftrace_filter_path, filters, module, reset, errs); + out: + tracefs_put_tracing_file(ftrace_filter_path); + return ret; +} -- 2.7.4