diff options
Diffstat (limited to 'src/tracefs-dynevents.c')
| -rw-r--r-- | src/tracefs-dynevents.c | 779 |
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); +} |