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-rw-r--r--src/tracefs-dynevents.c779
1 files changed, 779 insertions, 0 deletions
diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
new file mode 100644
index 0000000..7a3c45c
--- /dev/null
+++ b/src/tracefs-dynevents.c
@@ -0,0 +1,779 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ *
+ * Updates:
+ * Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+
+#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"
+
+#define EVENT_INDEX(B) (ffs(B) - 1)
+
+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 tracefs_dynevent_type type;
+ const char *file;
+ const char *prefix;
+ int (*del)(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn);
+ int (*parse)(struct dyn_events_desc *desc, const char *group,
+ char *line, struct tracefs_dynevent **ret_dyn);
+} dynevents[] = {
+ {TRACEFS_DYNEVENT_KPROBE, KPROBE_EVENTS, "p", dyn_generic_del, dyn_generic_parse},
+ {TRACEFS_DYNEVENT_KRETPROBE, KPROBE_EVENTS, "r", dyn_generic_del, dyn_generic_parse},
+ {TRACEFS_DYNEVENT_UPROBE, UPROBE_EVENTS, "p", dyn_generic_del, dyn_generic_parse},
+ {TRACEFS_DYNEVENT_URETPROBE, UPROBE_EVENTS, "r", dyn_generic_del, dyn_generic_parse},
+ {TRACEFS_DYNEVENT_EPROBE, "", "e", dyn_generic_del, dyn_generic_parse},
+ {TRACEFS_DYNEVENT_SYNTH, SYNTH_EVENTS, "", dyn_synth_del, dyn_synth_parse},
+};
+
+
+
+static 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;
+}
+
+/**
+ * tracefs_dynevent_free - Free a dynamic event context
+ * @devent: Pointer to a dynamic event context
+ *
+ * The dynamic event, described by this context, is not
+ * removed from the system by this API. It only frees the memory.
+ */
+void tracefs_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 void parse_prefix(char *word, char **prefix, char **system, char **name)
+{
+ char *sav;
+
+ *prefix = NULL;
+ *system = NULL;
+ *name = NULL;
+
+ *prefix = strtok_r(word, ":", &sav);
+ *system = strtok_r(NULL, "/", &sav);
+ if (!(*system))
+ return;
+
+ *name = strtok_r(NULL, " \t", &sav);
+ if (!(*name)) {
+ *name = *system;
+ *system = NULL;
+ }
+}
+
+/*
+ * Parse lines from dynamic_events, kprobe_events and uprobe_events files
+ * PREFIX[:[SYSTEM/]EVENT] [ADDRSS] [FORMAT]
+ */
+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 *word;
+ char *format = NULL;
+ char *address = NULL;
+ char *system;
+ char *prefix;
+ char *event;
+ char *sav;
+
+ if (strncmp(line, desc->prefix, strlen(desc->prefix)))
+ return -1;
+
+ word = strtok_r(line, " \t", &sav);
+ if (!word || *word == '\0')
+ return -1;
+
+ parse_prefix(word, &prefix, &system, &event);
+ if (!prefix)
+ return -1;
+
+ if (desc->type != TRACEFS_DYNEVENT_SYNTH) {
+ address = strtok_r(NULL, " \t", &sav);
+ if (!address || *address == '\0')
+ return -1;
+ }
+
+ format = strtok_r(NULL, "", &sav);
+
+ /* KPROBEs and UPROBEs share the same prefix, check the format */
+ if (desc->type & (TRACEFS_DYNEVENT_UPROBE | TRACEFS_DYNEVENT_URETPROBE)) {
+ if (!strchr(address, '/'))
+ return -1;
+ }
+
+ if (group && (!system || 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->prefix = strdup(prefix);
+ if (!dyn->prefix)
+ goto error;
+
+ if (system) {
+ dyn->system = strdup(system);
+ if (!dyn->system)
+ goto error;
+ }
+
+ if (event) {
+ dyn->event = strdup(event);
+ if (!dyn->event)
+ goto error;
+ }
+
+ if (address) {
+ dyn->address = strdup(address);
+ if (!dyn->address)
+ goto error;
+ }
+
+ if (format) {
+ dyn->format = strdup(format);
+ if (!dyn->format)
+ goto error;
+ }
+
+ *ret_dyn = dyn;
+ return 0;
+error:
+ tracefs_dynevent_free(dyn);
+ return -1;
+}
+
+static 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;
+}
+
+/*
+ * Parse lines from synthetic_events file
+ * EVENT ARG [ARG]
+ */
+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, " \t", &sav);
+ if (!event || *event == '\0')
+ return -1;
+
+ format = strtok_r(NULL, "", &sav);
+ if (!format || *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:
+ tracefs_dynevent_free(dyn);
+ return -1;
+}
+
+static void init_devent_desc(void)
+{
+ int i;
+
+ BUILD_BUG_ON(ARRAY_SIZE(dynevents) != EVENT_INDEX(TRACEFS_DYNEVENT_MAX));
+
+ if (!tracefs_file_exists(NULL, DYNEVENTS_EVENTS))
+ return;
+
+ /* Use ftrace dynamic_events, if available */
+ for (i = 0; i < EVENT_INDEX(TRACEFS_DYNEVENT_MAX); i++)
+ dynevents[i].file = DYNEVENTS_EVENTS;
+
+ dynevents[EVENT_INDEX(TRACEFS_DYNEVENT_SYNTH)].prefix = "s";
+}
+
+static struct dyn_events_desc *get_devent_desc(enum tracefs_dynevent_type type)
+{
+
+ static bool init;
+
+ if (type >= TRACEFS_DYNEVENT_MAX)
+ return NULL;
+
+ if (!init) {
+ init_devent_desc();
+ init = true;
+ }
+
+ return &dynevents[EVENT_INDEX(type)];
+}
+
+/**
+ * dynevent_alloc - Allocate new dynamic event
+ * @type: Type of the dynamic event
+ * @system: The system name (NULL for the default dynamic)
+ * @event: Name of the event
+ * @addr: The function and offset (or address) to insert the probe
+ * @format: The format string to define the probe.
+ *
+ * Allocate a dynamic event context that will be in the @system group
+ * (or dynamic if @system is NULL). Have the name of @event and
+ * will be associated to @addr, if applicable for that event type
+ * (function name, with or without offset, or a address). And the @format will
+ * define the format of the kprobe.
+ * The dynamic event is not created in the system.
+ *
+ * Return a pointer to a dynamic event context on success, or NULL on error.
+ * The returned pointer must be freed with tracefs_dynevent_free()
+ *
+ * errno will be set to EINVAL if event is NULL.
+ */
+__hidden struct tracefs_dynevent *
+dynevent_alloc(enum tracefs_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:
+ tracefs_dynevent_free(devent);
+ return NULL;
+}
+
+/**
+ * tracefs_dynevent_create - Create a dynamic event in the system
+ * @devent: Pointer to a dynamic event context, describing the event
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_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) ? ":" : "",
+ 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) ? ":" : "",
+ 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;
+}
+
+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);
+ }
+}
+
+/**
+ * tracefs_dynevent_destroy - Remove a dynamic event from the system
+ * @devent: A dynamic event context, describing the dynamic event that will be deleted.
+ * @force: Will attempt to disable all events before removing them.
+ *
+ * The dynamic event context is not freed by this API. It only removes the event from the system.
+ * If there are any enabled events, and @force is not set, then it will error with -1 and errno
+ * to be EBUSY.
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_dynevent_destroy(struct tracefs_dynevent *devent, bool force)
+{
+ struct dyn_events_desc *desc;
+ char **instance_list;
+
+ if (!devent)
+ return -1;
+
+ if (force) {
+ instance_list = tracefs_instances(NULL);
+ disable_events(devent->system, devent->event, instance_list);
+ tracefs_list_free(instance_list);
+ }
+
+ desc = get_devent_desc(devent->type);
+ if (!desc)
+ return -1;
+
+ return desc->del(desc, devent);
+}
+
+static int get_all_dynevents(enum tracefs_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->parse(desc, system, line, ret_all ? &devent : NULL);
+ if (!ret) {
+ if (ret_all) {
+ tmp = realloc(all, (count + 1) * sizeof(*tmp));
+ 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;
+
+ if (!events)
+ return;
+
+ for (i = 0; events[i]; i++)
+ tracefs_dynevent_free(events[i]);
+
+ free(events);
+}
+
+/**
+ * tracefs_dynevent_get_all - return an array of pointers to dynamic events of given types
+ * @types: Dynamic event type, or bitmask of dynamic event types. If 0 is passed, all types
+ * are considered.
+ * @system: Get events from that system only. If @system is NULL, events from all systems
+ * are returned.
+ *
+ * Returns an array of pointers to dynamic events of given types that exist in the system.
+ * The array must be freed with tracefs_dynevent_list_free(). If there are no events a NULL
+ * pointer is returned.
+ */
+struct tracefs_dynevent **
+tracefs_dynevent_get_all(unsigned int types, const char *system)
+{
+ struct tracefs_dynevent **events, **tmp, **all_events = NULL;
+ int count, all = 0;
+ int i;
+
+ for (i = 1; i < TRACEFS_DYNEVENT_MAX; i <<= 1) {
+ if (types) {
+ if (i > types)
+ break;
+ if (!(types & i))
+ continue;
+ }
+ count = get_all_dynevents(i, system, &events);
+ if (count > 0) {
+ tmp = realloc(all_events, (all + count + 1) * sizeof(*tmp));
+ if (!tmp)
+ goto error;
+ all_events = tmp;
+ memcpy(all_events + all, events, count * sizeof(*events));
+ all += count;
+ /* Add a NULL pointer at the end */
+ all_events[all] = NULL;
+ free(events);
+ }
+ }
+
+ return all_events;
+
+error:
+ if (all_events) {
+ for (i = 0; i < all; i++)
+ free(all_events[i]);
+ free(all_events);
+ }
+ return NULL;
+}
+
+/**
+ * tracefs_dynevent_get - return a single dynamic event if it exists
+ * @type; Dynamic event type
+ * @system: Get events from that system only. May be NULL.
+ * @event: Get event of the system type (may not be NULL)
+ *
+ * Returns the dynamic event of the given @type and @system for with the @event
+ * name. If @system is NULL, it will return the first dynamic event that it finds
+ * that matches the @event name.
+ *
+ * The returned event must be freed with tracefs_dynevent_free().
+ * NULL is returned if no event match is found, or other error.
+ */
+struct tracefs_dynevent *
+tracefs_dynevent_get(enum tracefs_dynevent_type type, const char *system,
+ const char *event)
+{
+ struct tracefs_dynevent **events;
+ struct tracefs_dynevent *devent = NULL;
+ int count;
+ int i;
+
+ if (!event) {
+ errno = -EINVAL;
+ return NULL;
+ }
+
+ count = get_all_dynevents(type, system, &events);
+ if (count <= 0)
+ return NULL;
+
+ for (i = 0; i < count; i++) {
+ if (strcmp(events[i]->event, event) == 0)
+ break;
+ }
+ if (i < count) {
+ devent = events[i];
+ events[i] = NULL;
+ }
+
+ tracefs_dynevent_list_free(events);
+
+ return devent;
+}
+
+/**
+ * tracefs_dynevent_destroy_all - removes all dynamic events of given types from the system
+ * @types: Dynamic event type, or bitmask of dynamic event types. If 0 is passed, all types
+ * are considered.
+ * @force: Will attempt to disable all events before removing them.
+ *
+ * Will remove all dynamic events of the given types from the system. If there are any enabled
+ * events, and @force is not set, then the removal of these will fail. If @force is set, then
+ * it will attempt to disable all the events in all instances before removing them.
+ *
+ * Returns zero if all requested events are removed successfully, or -1 if some of them are not
+ * removed.
+ */
+int tracefs_dynevent_destroy_all(unsigned int types, bool force)
+{
+ struct tracefs_dynevent **all;
+ int ret = 0;
+ int i;
+
+ all = tracefs_dynevent_get_all(types, NULL);
+ if (!all)
+ return 0;
+
+ for (i = 0; all[i]; i++) {
+ if (tracefs_dynevent_destroy(all[i], force))
+ ret = -1;
+ }
+
+ tracefs_dynevent_list_free(all);
+
+ return ret;
+}
+
+/**
+ * dynevent_get_count - Count dynamic events of given types and system
+ * @types: Dynamic event type, or bitmask of dynamic event types. If 0 is passed, all types
+ * are considered.
+ * @system: Count events from that system only. If @system is NULL, events from all systems
+ * are counted.
+ *
+ * Return the count of requested dynamic events
+ */
+__hidden int dynevent_get_count(unsigned int types, const char *system)
+{
+ int count, all = 0;
+ int i;
+
+ for (i = 1; i < TRACEFS_DYNEVENT_MAX; i <<= 1) {
+ if (types) {
+ if (i > types)
+ break;
+ if (!(types & i))
+ continue;
+ }
+ count = get_all_dynevents(i, system, NULL);
+ if (count > 0)
+ all += count;
+ }
+
+ return all;
+}
+
+static enum tracefs_dynevent_type
+dynevent_info(struct tracefs_dynevent *dynevent, char **system,
+ char **event, char **prefix, char **addr, char **format)
+{
+ char **lv[] = { system, event, prefix, addr, format };
+ char **rv[] = { &dynevent->system, &dynevent->event, &dynevent->prefix,
+ &dynevent->address, &dynevent->format };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(lv); i++) {
+ if (lv[i]) {
+ if (*rv[i]) {
+ *lv[i] = strdup(*rv[i]);
+ if (!*lv[i])
+ goto error;
+ } else {
+ *lv[i] = NULL;
+ }
+ }
+ }
+
+ return dynevent->type;
+
+error:
+ for (i--; i >= 0; i--) {
+ if (lv[i])
+ free(*lv[i]);
+ }
+
+ return TRACEFS_DYNEVENT_UNKNOWN;
+}
+
+/**
+ * tracefs_dynevent_info - return details of a dynamic event
+ * @dynevent: A dynamic event context, describing given dynamic event.
+ * @group: return, group in which the dynamic event is configured
+ * @event: return, name of the dynamic event
+ * @prefix: return, prefix string of the dynamic event
+ * @addr: return, the function and offset (or address) of the dynamic event
+ * @format: return, the format string of the dynamic event
+ *
+ * Returns the type of the dynamic event, or TRACEFS_DYNEVENT_UNKNOWN in case of an error.
+ * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
+ * If a valid pointer is passed, in case of success - a string is allocated and returned.
+ * These strings must be freed with free().
+ */
+enum tracefs_dynevent_type
+tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system,
+ char **event, char **prefix, char **addr, char **format)
+{
+ if (!dynevent)
+ return TRACEFS_DYNEVENT_UNKNOWN;
+
+ return dynevent_info(dynevent, system, event, prefix, addr, format);
+}
+
+/**
+ * tracefs_dynevent_get_event - return tep event representing the given dynamic event
+ * @tep: a handle to the trace event parser context that holds the events
+ * @dynevent: a dynamic event context, describing given dynamic event.
+ *
+ * Returns a pointer to a tep event describing the given dynamic event. The pointer
+ * is managed by the @tep handle and must not be freed. In case of an error, or in case
+ * the requested dynamic event is missing in the @tep handler - NULL is returned.
+ */
+struct tep_event *
+tracefs_dynevent_get_event(struct tep_handle *tep, struct tracefs_dynevent *dynevent)
+{
+ if (!tep || !dynevent || !dynevent->event)
+ return NULL;
+
+ return get_tep_event(tep, dynevent->system, dynevent->event);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 00:23:47 +0000