From patchwork Mon Nov 1 09:08:53 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: 12596159 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 BAEE9C433FE for ; Mon, 1 Nov 2021 09:09:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A0D40610CB for ; Mon, 1 Nov 2021 09:09:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231582AbhKAJLm (ORCPT ); Mon, 1 Nov 2021 05:11:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231223AbhKAJLm (ORCPT ); Mon, 1 Nov 2021 05:11:42 -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 3D48CC061714 for ; Mon, 1 Nov 2021 02:09:09 -0700 (PDT) Received: by mail-ed1-x529.google.com with SMTP id g14so33563edz.2 for ; Mon, 01 Nov 2021 02:09:09 -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=0Ag3+lRl3WjP9UUCaGr1JGeRjb8a7DbSjVhJSHCr2jk=; b=ghMlyPsEgjQDF98DKuLKlvlou+hSY6eU2PcJWNsUiJbpOHSLVjF2tVJ3NB27wX22IA 3h3B4zFy4xXpGaSn0zo5Du5pHPNJ6UjJt6wMl/ZGn3CAb7DAJmlhChhW1CAOczJHOCbZ kEnbnC9uBFLenm0Ff6Kwy9NRhkRsmUdjzOntx3KCxIyLPbkirUeSuHrvyYaiJtYTseCf DuGiTMruQ41jLwLIeNxVTIkLVsp8QyZrBvUp9RrBRl6kgtkz+dUtUflFv+V5kddA0V1o QZpG5Cj96y514geymo4DcaW0YgO1dBHRBw2uyKM/rtOiQx0J+wDTO4KyH9Qz5pA/MgBL z6Yw== 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=0Ag3+lRl3WjP9UUCaGr1JGeRjb8a7DbSjVhJSHCr2jk=; b=GfFTOKSX2boMFAGze3ZdVMo1uG162PtZxTSKbL8qIwY3wjVPdgOwKmSKPY0CdEnNrX O8GKjVqwdsp+0h+cbPWDnkDpbpCzv5/iE3jAD5u7GRrJwfi/NGgpN0XVmiiFEWPv8qB/ Wgevoz1Bno9X/OAcSgN5sKAkeSjS5SZCvbTAGsSgKEFEwHO4ng3IBzFLoxmEA45QO2uI 5yxPPJd7lXHCnQIuBKuVzmS6sqs70XM/yBry3+LpFULmIPmUD37v1Qg3YMa6NXqICYsr bP4mL8Y6zjlozLoeNwsrbiTsr0DU0yd7CgdySgfMtp79ROdLrQz0uBL/kvodjqa8H6AZ TaoA== X-Gm-Message-State: AOAM532dcpI2EGPhsWsw0epkPQHzjgzInLzcYZc7P3PBzcegaKxlpMJx lJBNIgmAXg6xHd0q+RUeQ9a32fcBsy0q3w== X-Google-Smtp-Source: ABdhPJzowwEve4Tv71glvrbF6lehsih27fSpXnc8QPZpHtHtNv/stGgjunR/v/eCWTzeYaOyhGzwLQ== X-Received: by 2002:a50:d49c:: with SMTP id s28mr14122389edi.174.1635757747748; Mon, 01 Nov 2021 02:09:07 -0700 (PDT) Received: from oberon.zico.biz ([83.222.187.186]) by smtp.gmail.com with ESMTPSA id i8sm9873222edc.10.2021.11.01.02.09.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Nov 2021 02:09:07 -0700 (PDT) From: "Tzvetomir Stoyanov (VMware)" To: rostedt@goodmis.org, y.karadz@gmail.com Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v2 01/12] libtracefs: Add new internal APIs for dynamic events Date: Mon, 1 Nov 2021 11:08:53 +0200 Message-Id: <20211101090904.81454-2-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 Ftrace supports dynamic events, created by the user - kprobes, uprobes, eprobes and synthetic events. There are two interfaces for managing these events - new common "dynamic_events" file and event specific "kprobe_events", "uprobe_events", "synthetic_events" files. The configuration syntax for all dynamic events is almost the same. To simplify support of dynamic events in thw tracefs library, a new internal helper layer is implemented. It handles both configuration interfaces - the common "dynamic_events" file is preferred, if available. On the old kernels, where this file is missing, the event specific files are used. The new helper layer can be used to create, delete and get ftrace dynamic events form any type. Most of the APIs are internal, not exposed to the library users. Only one API is exposed publicly: tracefs_dynevent_list_free() This new logic is designed to be used internally within the library, from the APIs that implement kprobes, uprobes, eprobes and synthetic events support. Signed-off-by: Tzvetomir Stoyanov (VMware) --- include/tracefs-local.h | 35 +++ include/tracefs.h | 3 + src/Makefile | 1 + src/tracefs-dynevents.c | 492 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 531 insertions(+) create mode 100644 src/tracefs-dynevents.c diff --git a/include/tracefs-local.h b/include/tracefs-local.h index 684eccf..60440c6 100644 --- a/include/tracefs-local.h +++ b/include/tracefs-local.h @@ -15,6 +15,10 @@ #define BUILD_BUG_ON(cond) \ do { if (!(1/!(cond))) { } } while (0) +#define SET_BIT(M, B) do { (M) |= (1ULL << (B)); } while (0) +#define TEST_BIT(M, B) ((M) & (1ULL<<(B))) +#define CLEAR_BIT(M, B) do { (M) &= ~(1ULL << (B)); } while (0) + struct tracefs_options_mask { unsigned long long mask; }; @@ -94,4 +98,35 @@ int synth_add_start_field(struct tracefs_synth *synth, const char *start_field, const char *name, enum tracefs_hist_key_type type); + +/* Internal interface for ftrace dynamic events */ +enum trace_dynevent_type { + TRACE_DYNEVENT_KPROBE = 0, + TRACE_DYNEVENT_KRETPROBE, + TRACE_DYNEVENT_UPROBE, + TRACE_DYNEVENT_URETPROBE, + TRACE_DYNEVENT_EPROBE, + TRACE_DYNEVENT_SYNTH, + TRACE_DYNEVENT_MAX, +}; + +struct tracefs_dynevent { + char *trace_file; + char *prefix; + char *system; + char *event; + char *address; + char *format; + enum trace_dynevent_type type; +}; + +struct tracefs_dynevent * +dynevent_alloc(enum trace_dynevent_type type, const char *system, + const char *event, const char *address, const char *format); +void dynevent_free(struct tracefs_dynevent *devent); +int dynevent_create(struct tracefs_dynevent *devent); +int dynevent_destroy(struct tracefs_dynevent *devent); +struct tracefs_dynevent **dynevent_get_all(unsigned long type_mask, const char *system); +int dynevent_get_count(unsigned long type_mask, const char *system); + #endif /* _TRACE_FS_LOCAL_H */ diff --git a/include/tracefs.h b/include/tracefs.h index a2cda30..ee167be 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -238,6 +238,9 @@ ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags); void tracefs_trace_pipe_stop(struct tracefs_instance *instance); +struct tracefs_dynevent; +void tracefs_dynevent_list_free(struct tracefs_dynevent **events); + enum tracefs_kprobe_type { TRACEFS_ALL_KPROBES, TRACEFS_KPROBE, diff --git a/src/Makefile b/src/Makefile index 4e38d98..99cd7da 100644 --- a/src/Makefile +++ b/src/Makefile @@ -11,6 +11,7 @@ OBJS += tracefs-marker.o OBJS += tracefs-kprobes.o OBJS += tracefs-hist.o OBJS += tracefs-filter.o +OBJS += tracefs-dynevents.o # Order matters for the the three below OBJS += sqlhist-lex.o diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c new file mode 100644 index 0000000..0de4c49 --- /dev/null +++ b/src/tracefs-dynevents.c @@ -0,0 +1,492 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright (C) 2021 VMware Inc, Steven Rostedt + * + * Updates: + * Copyright (C) 2021, VMware, Tzvetomir Stoyanov + * + */ +#include +#include +#include +#include +#include +#include +#include + +#include "tracefs.h" +#include "tracefs-local.h" + +#define DYNEVENTS_EVENTS "dynamic_events" +#define KPROBE_EVENTS "kprobe_events" +#define UPROBE_EVENTS "uprobe_events" +#define SYNTH_EVENTS "synthetic_events" +#define DYNEVENTS_DEFAULT_GROUP "dynamic" + +struct dyn_events_desc; +static int dyn_generic_parse(struct dyn_events_desc *, + const char *, char *, struct tracefs_dynevent **); +static int dyn_synth_parse(struct dyn_events_desc *, + const char *, char *, struct tracefs_dynevent **); +static int dyn_generic_del(struct dyn_events_desc *, struct tracefs_dynevent *); +static int dyn_synth_del(struct dyn_events_desc *, struct tracefs_dynevent *); + +struct dyn_events_desc { + enum trace_dynevent_type type; + const char *file; + const char *prefix; + int (*dyn_events_del)(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn); + int (*dyn_events_parse)(struct dyn_events_desc *desc, const char *group, + char *line, struct tracefs_dynevent **ret_dyn); +} dynevents[] = { + {TRACE_DYNEVENT_KPROBE, NULL, "p", dyn_generic_del, dyn_generic_parse}, + {TRACE_DYNEVENT_KRETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse}, + {TRACE_DYNEVENT_UPROBE, NULL, "p", dyn_generic_del, dyn_generic_parse}, + {TRACE_DYNEVENT_URETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse}, + {TRACE_DYNEVENT_EPROBE, NULL, "e", dyn_generic_del, dyn_generic_parse}, + {TRACE_DYNEVENT_SYNTH, NULL, "s", dyn_synth_del, dyn_synth_parse}, +}; + +int dyn_generic_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn) +{ + char *str; + int ret; + + if (dyn->system) + ret = asprintf(&str, "-:%s/%s", dyn->system, dyn->event); + else + ret = asprintf(&str, "-:%s", dyn->event); + + if (ret < 0) + return -1; + + ret = tracefs_instance_file_append(NULL, desc->file, str); + free(str); + + return ret < 0 ? ret : 0; +} + +__hidden void dynevent_free(struct tracefs_dynevent *devent) +{ + if (!devent) + return; + free(devent->system); + free(devent->event); + free(devent->address); + free(devent->format); + free(devent->prefix); + free(devent->trace_file); + free(devent); +} + +static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group, + char *line, struct tracefs_dynevent **ret_dyn) +{ + struct tracefs_dynevent *dyn; + char *format = NULL; + char *address; + char *system; + char *prefix; + char *event; + char *sav; + + if (strncmp(line, desc->prefix, strlen(desc->prefix))) + return -1; + + prefix = strtok_r(line, ":", &sav); + if (!prefix) + return -1; + system = strtok_r(NULL, "/", &sav); + if (!system) + return -1; + event = strtok_r(NULL, " ", &sav); + if (!event) + return -1; + address = strtok_r(NULL, " ", &sav); + if (!address) + address = event + strlen(event) + 1; + else + format = address + strlen(address) + 1; + + /* KPROBEs and UPROBEs share the same prefix, check the format */ + if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) { + if (!strchr(address, '/')) + return -1; + } + if (group && strcmp(group, system) != 0) + return -1; + + if (!ret_dyn) + return 0; + + dyn = calloc(1, sizeof(*dyn)); + if (!dyn) + return -1; + + dyn->type = desc->type; + dyn->trace_file = strdup(desc->file); + if (!dyn->trace_file) + goto error; + dyn->system = strdup(system); + if (!dyn->system) + goto error; + /* Prefix of KRETPROBE can contain MAXACTIVE integer */ + dyn->prefix = strdup(prefix); + if (!dyn->prefix) + goto error; + dyn->event = strdup(event); + if (!dyn->event) + goto error; + if (desc->type == TRACE_DYNEVENT_SYNTH) { + /* Synthetic events have no address */ + dyn->format = strdup(address); + if (!dyn->format) + goto error; + } else { + dyn->address = strdup(address); + if (!dyn->address) + goto error; + if (*format != '\0') { + dyn->format = strdup(format); + if (!dyn->format) + goto error; + } + } + *ret_dyn = dyn; + return 0; +error: + dynevent_free(dyn); + return -1; +} + +int dyn_synth_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn) +{ + char *str; + int ret; + + if (strcmp(desc->file, DYNEVENTS_EVENTS)) + return dyn_generic_del(desc, dyn); + + ret = asprintf(&str, "!%s", dyn->event); + if (ret < 0) + return -1; + + ret = tracefs_instance_file_append(NULL, desc->file, str); + free(str); + + return ret < 0 ? ret : 0; +} + +static int dyn_synth_parse(struct dyn_events_desc *desc, const char *group, + char *line, struct tracefs_dynevent **ret_dyn) +{ + struct tracefs_dynevent *dyn; + char *format; + char *event; + char *sav; + + if (strcmp(desc->file, DYNEVENTS_EVENTS)) + return dyn_generic_parse(desc, group, line, ret_dyn); + + /* synthetic_events file has slightly different syntax */ + event = strtok_r(line, " ", &sav); + if (!event) + return -1; + + format = event + strlen(event) + 1; + if (*format == '\0') + return -1; + if (!ret_dyn) + return 0; + + dyn = calloc(1, sizeof(*dyn)); + if (!dyn) + return -1; + dyn->type = desc->type; + dyn->trace_file = strdup(desc->file); + if (!dyn->trace_file) + goto error; + + dyn->event = strdup(event); + if (!dyn->event) + goto error; + dyn->format = strdup(format+1); + if (!dyn->format) + goto error; + + *ret_dyn = dyn; + return 0; +error: + dynevent_free(dyn); + return -1; +} + +static void init_devent_desc(void) +{ + int i; + + BUILD_BUG_ON(ARRAY_SIZE(dynevents) != TRACE_DYNEVENT_MAX); + + /* Use ftrace dynamic_events, if available */ + if (tracefs_file_exists(NULL, DYNEVENTS_EVENTS)) { + for (i = 0; i < TRACE_DYNEVENT_MAX; i++) + dynevents[i].file = DYNEVENTS_EVENTS; + return; + } + + if (tracefs_file_exists(NULL, KPROBE_EVENTS)) { + dynevents[TRACE_DYNEVENT_KPROBE].file = KPROBE_EVENTS; + dynevents[TRACE_DYNEVENT_KRETPROBE].file = KPROBE_EVENTS; + } + if (tracefs_file_exists(NULL, UPROBE_EVENTS)) { + dynevents[TRACE_DYNEVENT_UPROBE].file = UPROBE_EVENTS; + dynevents[TRACE_DYNEVENT_URETPROBE].file = UPROBE_EVENTS; + } + if (tracefs_file_exists(NULL, SYNTH_EVENTS)) { + dynevents[TRACE_DYNEVENT_SYNTH].file = SYNTH_EVENTS; + dynevents[TRACE_DYNEVENT_SYNTH].prefix = ""; + } + +} + +static struct dyn_events_desc *get_devent_desc(enum trace_dynevent_type type) +{ + static bool init; + + if (!init) { + init_devent_desc(); + init = true; + } + + return &dynevents[type]; +} + +__hidden struct tracefs_dynevent * +dynevent_alloc(enum trace_dynevent_type type, const char *system, + const char *event, const char *address, const char *format) +{ + struct tracefs_dynevent *devent; + struct dyn_events_desc *desc; + + if (!event) { + errno = EINVAL; + return NULL; + } + + desc = get_devent_desc(type); + if (!desc || !desc->file) { + errno = ENOTSUP; + return NULL; + } + + devent = calloc(1, sizeof(*devent)); + if (!devent) + return NULL; + + devent->type = type; + devent->trace_file = strdup(desc->file); + if (!devent->trace_file) + goto err; + + if (!system) + system = DYNEVENTS_DEFAULT_GROUP; + devent->system = strdup(system); + if (!devent->system) + goto err; + + devent->event = strdup(event); + if (!devent->event) + goto err; + + devent->prefix = strdup(desc->prefix); + if (!devent->prefix) + goto err; + + if (address) { + devent->address = strdup(address); + if (!devent->address) + goto err; + } + if (format) { + devent->format = strdup(format); + if (!devent->format) + goto err; + } + + return devent; +err: + dynevent_free(devent); + return NULL; +} + +__hidden int dynevent_create(struct tracefs_dynevent *devent) +{ + char *str; + int ret; + + if (!devent) + return -1; + + if (devent->system && devent->system[0]) + ret = asprintf(&str, "%s%s%s/%s %s %s\n", + devent->prefix, strlen(devent->prefix) > 0 ? ":" : "", + devent->system, devent->event, + devent->address ? devent->address : "", + devent->format ? devent->format : ""); + else + ret = asprintf(&str, "%s%s%s %s %s\n", + devent->prefix, strlen(devent->prefix) > 0 ? ":" : "", + devent->event, + devent->address ? devent->address : "", + devent->format ? devent->format : ""); + if (ret < 0) + return -1; + + ret = tracefs_instance_file_append(NULL, devent->trace_file, str); + free(str); + + return ret < 0 ? ret : 0; +} + +__hidden int dynevent_destroy(struct tracefs_dynevent *devent) +{ + struct dyn_events_desc *desc; + + if (!devent) + return -1; + + desc = get_devent_desc(devent->type); + if (!desc) + return -1; + + return desc->dyn_events_del(desc, devent); +} + +static int get_all_type(enum trace_dynevent_type type, const char *system, + struct tracefs_dynevent ***ret_all) +{ + struct dyn_events_desc *desc; + struct tracefs_dynevent *devent, **tmp, **all = NULL; + char *content; + int count = 0; + char *line; + char *next; + int ret; + + desc = get_devent_desc(type); + if (!desc) + return -1; + + content = tracefs_instance_file_read(NULL, desc->file, NULL); + if (!content) + return -1; + + line = content; + do { + next = strchr(line, '\n'); + if (next) + *next = '\0'; + ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL); + if (!ret) { + if (ret_all) { + tmp = realloc(all, (count+1)*sizeof(struct tracefs_dynevent *)); + if (!tmp) + goto error; + all = tmp; + all[count] = devent; + } + count++; + } + line = next + 1; + } while (next); + + free(content); + if (ret_all) + *ret_all = all; + return count; + +error: + free(content); + free(all); + return -1; +} + +/** + * tracefs_dynevent_list_free - Deletes an array of pointers to dynamic event contexts + * @events: An array of pointers to dynamic event contexts. The last element of the array + * must be a NULL pointer. + */ +void tracefs_dynevent_list_free(struct tracefs_dynevent **events) +{ + int i = 0; + + if (!events) + return; + + while (events[i]) + dynevent_free(events[i++]); + + free(events); +} + +__hidden struct tracefs_dynevent **dynevent_get_all(unsigned long type_mask, const char *system) +{ + struct tracefs_dynevent **events, **tmp, **all_events = NULL; + int count, all = 0; + int i; + + for (i = 0; i < TRACE_DYNEVENT_MAX; i++) { + if (!TEST_BIT(type_mask, i)) + continue; + + count = get_all_type(i, system, &events); + if (count > 0) { + tmp = realloc(all_events, + (all + count)*sizeof(struct tracefs_dynevent *)); + if (!tmp) + goto error; + all_events = tmp; + memcpy(all_events + all, events, + count*sizeof(struct tracefs_dynevent *)); + all += count; + } + + } + + /* Add a NULL pointer at the end */ + if (all > 0) { + tmp = realloc(all_events, + (all + 1)*sizeof(struct tracefs_dynevent *)); + if (!tmp) + goto error; + + all_events = tmp; + all_events[all] = NULL; + } + + return all_events; + +error: + if (all_events) { + for (i = 0; i < all; i++) + free(all_events[i]); + free(all_events); + } + return NULL; +} + +__hidden int dynevent_get_count(unsigned long type_mask, const char *system) +{ + int count, all = 0; + int i; + + for (i = 0; i < TRACE_DYNEVENT_MAX; i++) { + if (!TEST_BIT(type_mask, i)) + continue; + count = get_all_type(i, system, NULL); + if (count > 0) + all += count; + } + + return all; +}