From patchwork Tue Mar 23 01:27:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 12156557 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2C943C433C1 for ; Tue, 23 Mar 2021 01:33:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E776A619AF for ; Tue, 23 Mar 2021 01:33:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231441AbhCWBdE (ORCPT ); Mon, 22 Mar 2021 21:33:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:44330 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231434AbhCWBc1 (ORCPT ); Mon, 22 Mar 2021 21:32:27 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DDAEB61990; Tue, 23 Mar 2021 01:32:25 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94) (envelope-from ) id 1lOVuC-001cMk-RN; Mon, 22 Mar 2021 21:32:24 -0400 Message-ID: <20210323013224.729594322@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 22 Mar 2021 21:27:56 -0400 From: Steven Rostedt To: linux-trace-devel@vger.kernel.org Cc: Sameeruddin shaik , "Tzvetomir Stoyanov (VMware)" Subject: [PATCH 1/7] libtracefs: An API to set the filtering of functions References: <20210323012755.155237800@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: Sameeruddin shaik 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 Link: https://lore.kernel.org/linux-trace-devel/1616171938-18914-1-git-send-email-sameeruddin.shaik8@gmail.com Acked-by: "Tzvetomir Stoyanov (VMware)" Signed-off-by: Sameeruddin shaik Signed-off-by: Steven Rostedt (VMware) --- include/tracefs.h | 3 +- src/tracefs-tools.c | 111 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 113 insertions(+), 1 deletion(-) diff --git a/include/tracefs.h b/include/tracefs.h index f3eec62025f5..c1f07b0914f0 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -145,5 +145,6 @@ bool tracefs_option_is_enabled(struct tracefs_instance *instance, enum tracefs_o int tracefs_option_enable(struct tracefs_instance *instance, enum tracefs_option_id id); int tracefs_option_diasble(struct tracefs_instance *instance, enum tracefs_option_id id); const char *tracefs_option_name(enum tracefs_option_id id); - +int tracefs_function_filter(struct tracefs_instance *instance, const char **filters, + const char *module, bool reset, const char ***errs); #endif /* _TRACE_FS_H */ diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c index e2dfc7b8acff..4f8bcdc299df 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 +388,113 @@ 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; + const char **temp = NULL; + const char **e = NULL; + char *each_str = NULL; + int write_size = 0; + int size = 0; + int fd = -1; + int ret = 0; + int j = 0; + int i; + + fd = open(filter_path, O_WRONLY | flags); + if (fd < 0) + return 1; + + for (i = 0; filters[i]; i++) { + if (module) + write_size = asprintf(&each_str, "%s:mod:%s ", filters[i], module); + else + write_size = asprintf(&each_str, "%s ", filters[i]); + if (write_size < 0) { + ret = 1; + goto error; + } + size = write(fd, each_str, write_size); + /* compare written bytes*/ + if (size < write_size) { + if (errs) { + temp = realloc(e, (j + 1) * (sizeof(char *))); + if (!temp) { + free(e); + ret = 1; + goto error; + } else + e = temp; + + e[j++] = filters[i]; + ret -= 1; + } + } + free(each_str); + each_str = NULL; + } + if (errs) { + temp = realloc(e, (j + 1) * (sizeof(char *))); + if (!temp) { + free(e); + ret = 1; + goto error; + } else + e = temp; + e[j] = NULL; + *errs = e; + } + error: + if (each_str) + free(each_str); + 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: A pointer to array of constant strings that will be allocated + * on negative return of this function, pointing to the filters that + * failed.May be NULL, in which case this field will be ignored. + * + * 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 @filters. Otherwise, the functions set + * by @filters will be appended to the filter file + * + * returns -x on filter errors (where x is number of failed filter + * srtings) and if @errs is not NULL will be an allocated string array + * pointing to the strings in @filters that failed and must be freed + * with free(). + * + * returns 1 on general errors not realted to setting the filter. + * @errs is not set even if supplied. + * + * return 0 on success and @errs is not set. + */ +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) + return 1; + + ret = controlled_write(ftrace_filter_path, filters, module, reset, errs); + tracefs_put_tracing_file(ftrace_filter_path); + return ret; +}