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=-14.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 2D770C11F68 for ; Fri, 2 Jul 2021 11:10:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 043F961422 for ; Fri, 2 Jul 2021 11:10:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230498AbhGBLNY (ORCPT ); Fri, 2 Jul 2021 07:13:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230424AbhGBLNX (ORCPT ); Fri, 2 Jul 2021 07:13:23 -0400 Received: from mail-wm1-x32b.google.com (mail-wm1-x32b.google.com [IPv6:2a00:1450:4864:20::32b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5112C061762 for ; Fri, 2 Jul 2021 04:10:50 -0700 (PDT) Received: by mail-wm1-x32b.google.com with SMTP id j39-20020a05600c1c27b029020028e48b8fso452494wms.0 for ; Fri, 02 Jul 2021 04:10:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=jz7LcsVd9TAAEtkyFW0BTciYkgBjKqx/JhrTethzbgk=; b=cmHFRuJOIo/o5/+70wMCuinR63uOWir/t8Z0T2EKQVPIKxd8DwetnUpteyebifQBCk UDiYWaRmmp+dy86WEHKShd6aoA7RTEWXwI5fafVwoQzquMTRbCxRP3/n0TXhD75MkOwy rYyZROSVCVcUPTsTchlPZNJQyR48LsNPgjRfkPhZIhOznKtkLfOOtw4l6PYWfQL41lpM gnWXlCIJjBdxzTFnAj50zwOH/KH7PohHITV2Oit3FuVs03ND5+bTWzfm/YXaiRH8o1fG icKhou6yTZtGLnNhAkOVYhYpWzcx23x0uDyVsnTZ/abpLdFjc1ndVG1kXVp3J36csybb gIRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=jz7LcsVd9TAAEtkyFW0BTciYkgBjKqx/JhrTethzbgk=; b=OvqgC2t2/9Af+t7nedbrzn2rNY0RhMOOHSpCtxW54W6y8oqW5GOENkt1vIfJ5bSyuD dz8uWMIs9rh72L0LtOSUB35c8Zy+qxr6h7vD95txREfbaBt6ilV3cx9RAkHenJSbgKnY RomIxYgfzrRIpS8QJUz3sUwRGQousFuROAOxyibtl3D3mO8hKZM/Ci7gS5HNvEsZdaoG sd4ghuy21YIvqr1xSltmyX0DLB/p82YQyVVsgIhgQp2psggzPHseitN5OZ+WgTHz2kfr Nt66wr2le62REBd530cE17hZbn2HWAAR7O1iSi9J8qFGMCgtW6Hv4V7W7LXTGedqaYG4 tDRg== X-Gm-Message-State: AOAM533c8NsvIkwg1vUaJ6SltOEh8UdetMHglNA2OwvSGQfmoB3gNFbI scf5zu1glJO3KYWC1dTramDjjAtbuM4= X-Google-Smtp-Source: ABdhPJzokSzzFY8vb0MYlXqI7Rp0cSGqAH0KCgzjrctkI99ORhxnuBIZ5Szv/TndZS1B9bhtz7a3FA== X-Received: by 2002:a05:600c:4304:: with SMTP id p4mr6987956wme.43.1625224248533; Fri, 02 Jul 2021 04:10:48 -0700 (PDT) Received: from [10.93.171.151] ([146.247.46.134]) by smtp.gmail.com with ESMTPSA id b187sm13552022wmh.32.2021.07.02.04.10.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 02 Jul 2021 04:10:47 -0700 (PDT) Subject: Re: [PATCH v4 1/7] libtracefs: Implement tracefs_instances() To: Steven Rostedt , linux-trace-devel@vger.kernel.org References: <20210702035443.154729-1-rostedt@goodmis.org> <20210702035443.154729-2-rostedt@goodmis.org> From: "Yordan Karadzhov (VMware)" Message-ID: <4335f4d8-73eb-a2e4-f439-95cbe69acff2@gmail.com> Date: Fri, 2 Jul 2021 14:10:46 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210702035443.154729-2-rostedt@goodmis.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On 2.07.21 г. 6:54, Steven Rostedt wrote: > From: "Steven Rostedt (VMware)" > > Implement tracefs_instances() that will take a regex (or NULL for all) and > return a list of instances in the system. > > Signed-off-by: Steven Rostedt (VMware) > --- > include/tracefs.h | 1 + > src/tracefs-instance.c | 78 ++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 79 insertions(+) > > diff --git a/include/tracefs.h b/include/tracefs.h > index da8ad4189d4d..a21d2d2f22a6 100644 > --- a/include/tracefs.h > +++ b/include/tracefs.h > @@ -44,6 +44,7 @@ int tracefs_instance_file_read_number(struct tracefs_instance *instance, > int tracefs_instance_file_open(struct tracefs_instance *instance, > const char *file, int mode); > int tracefs_instances_walk(int (*callback)(const char *, void *), void *context); > +char **tracefs_instances(const char *regex); > > bool tracefs_instance_exists(const char *name); > bool tracefs_file_exists(struct tracefs_instance *instance, const char *name); > diff --git a/src/tracefs-instance.c b/src/tracefs-instance.c > index 2aeb529903bd..d833fae0fb0c 100644 > --- a/src/tracefs-instance.c > +++ b/src/tracefs-instance.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > #include > #include > #include "tracefs.h" > @@ -630,6 +631,83 @@ out: > return fret; > } > > +static inline bool match(const char *str, regex_t *re) > +{ > + if (!re) > + return true; > + return regexec(re, str, 0, NULL, 0) == 0; > +} > + > +struct instance_list { > + regex_t *re; > + char **list; > + int size; > + int failed; > +}; > + > +static int build_list(const char *name, void *data) > +{ > + struct instance_list *list = data; > + char **instances; > + int ret = -1; > + > + if (!match(name, list->re)) > + return 0; > + > + instances = realloc(list->list, list->size + 2); > + if (!instances) > + goto out; > + > + list->list = instances; Hi Steven, I am not sure what was your original intention here, but this doesn't seem to work properly. Maybe we need something like this: int size = sizeof(*instances) * (list->size + 2); instances = realloc(list->list, size); if (!instances) goto out; instances[list->size + 1] = NULL; > + list->list[list->size] = strdup(name); > + if (!list->list[list->size]) > + goto out; > + > + list->size++; > + ret = 0; > + > + out: > + list->failed = ret; > + return ret; > +} > + > +/** > + * tracefs_instances - return a list of instance names > + * @regex: A regex of instances to filter on (NULL to match all) > + * > + * Returns a list of names of existing instances, that must be > + * freed with tracefs_list_free(). Note, if there are no matches > + * then an empty list will be returned (not NULL). > + * NULL on error. > + */ > +char **tracefs_instances(const char *regex) > +{ > + struct instance_list list = { .re = NULL, .list = NULL }; > + regex_t re; > + int ret; > + > + if (regex) { > + ret = regcomp(&re, regex, REG_ICASE|REG_NOSUB); > + if (ret < 0) > + return NULL; > + list.re = &re; > + } > + > + ret = tracefs_instances_walk(build_list, &list); > + if (ret < 0 || list.failed) { > + tracefs_list_free(list.list); > + list.list = NULL; > + } else { > + if (!list.list) { > + /* No matches should produce an empty list */ > + list.list = malloc(sizeof(*list.list)); > + if (list.list) > + list.list[0] = NULL; > + } Or you can just do: return calloc(1, sizeof(*list.list)); Thanks! Yordan > + } > + return list.list; > +} > + > /** > * tracefs_get_clock - Get the current trace clock > * @instance: ftrace instance, can be NULL for the top instance >