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Diffstat (limited to 'src/tracefs-events.c')
| -rw-r--r-- | src/tracefs-events.c | 1515 |
1 files changed, 1515 insertions, 0 deletions
diff --git a/src/tracefs-events.c b/src/tracefs-events.c new file mode 100644 index 0000000..c2adf41 --- /dev/null +++ b/src/tracefs-events.c @@ -0,0 +1,1515 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright (C) 2008, 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> + * + * Updates: + * Copyright (C) 2019, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com> + * + */ +#include <stdio.h> +#include <stdlib.h> +#include <dirent.h> +#include <unistd.h> +#include <errno.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <limits.h> + +#include <kbuffer.h> + +#include "tracefs.h" +#include "tracefs-local.h" + +static struct follow_event *root_followers; +static int nr_root_followers; + +static struct follow_event *root_missed_followers; +static int nr_root_missed_followers; + +struct cpu_iterate { + struct tracefs_cpu *tcpu; + struct tep_record record; + struct tep_event *event; + struct kbuffer *kbuf; + void *page; + int psize; + int cpu; +}; + +static int read_kbuf_record(struct cpu_iterate *cpu) +{ + unsigned long long ts; + void *ptr; + + if (!cpu || !cpu->kbuf) + return -1; + ptr = kbuffer_read_event(cpu->kbuf, &ts); + if (!ptr) + return -1; + + memset(&cpu->record, 0, sizeof(cpu->record)); + cpu->record.ts = ts; + cpu->record.size = kbuffer_event_size(cpu->kbuf); + cpu->record.record_size = kbuffer_curr_size(cpu->kbuf); + cpu->record.missed_events = kbuffer_missed_events(cpu->kbuf); + cpu->record.cpu = cpu->cpu; + cpu->record.data = ptr; + cpu->record.ref_count = 1; + + kbuffer_next_event(cpu->kbuf, NULL); + + return 0; +} + +int read_next_page(struct tep_handle *tep, struct cpu_iterate *cpu) +{ + enum kbuffer_long_size long_size; + enum kbuffer_endian endian; + int r; + + if (!cpu->tcpu) + return -1; + + r = tracefs_cpu_buffered_read(cpu->tcpu, cpu->page, true); + /* + * tracefs_cpu_buffered_read() only reads in full subbuffer size, + * but this wants partial buffers as well. If the function returns + * empty (-1 for EAGAIN), try tracefs_cpu_read() next, as that can + * read partially filled buffers too, but isn't as efficient. + */ + if (r <= 0) + r = tracefs_cpu_read(cpu->tcpu, cpu->page, true); + if (r <= 0) + return -1; + + if (!cpu->kbuf) { + if (tep_is_file_bigendian(tep)) + endian = KBUFFER_ENDIAN_BIG; + else + endian = KBUFFER_ENDIAN_LITTLE; + + if (tep_get_header_page_size(tep) == 8) + long_size = KBUFFER_LSIZE_8; + else + long_size = KBUFFER_LSIZE_4; + + cpu->kbuf = kbuffer_alloc(long_size, endian); + if (!cpu->kbuf) + return -1; + } + + kbuffer_load_subbuffer(cpu->kbuf, cpu->page); + if (kbuffer_subbuffer_size(cpu->kbuf) > r) { + tracefs_warning("%s: page_size > %d", __func__, r); + return -1; + } + + return 0; +} + +int read_next_record(struct tep_handle *tep, struct cpu_iterate *cpu) +{ + int id; + + do { + while (!read_kbuf_record(cpu)) { + id = tep_data_type(tep, &(cpu->record)); + cpu->event = tep_find_event(tep, id); + if (cpu->event) + return 0; + } + } while (!read_next_page(tep, cpu)); + + return -1; +} + +/** + * tracefs_follow_missed_events - Add callback for missed events for iterators + * @instance: The instance to follow + * @callback: The function to call when missed events is detected + * @callback_data: The data to pass to @callback + * + * This attaches a callback to an @instance or the root instance if @instance + * is NULL, where if tracefs_iterate_raw_events() is called, that if missed + * events are detected, it will call @callback, with the following parameters: + * @event: The event pointer of the record with the missing events + * @record; The event instance of @event. + * @cpu: The cpu that the event happened on. + * @callback_data: The same as @callback_data passed to the function. + * + * If the count of missing events is available, @record->missed_events + * will have a positive number holding the number of missed events since + * the last event on the same CPU, or just -1 if that number is unknown + * but missed events did happen. + * + * Returns 0 on success and -1 on error. + */ +int tracefs_follow_missed_events(struct tracefs_instance *instance, + int (*callback)(struct tep_event *, + struct tep_record *, + int, void *), + void *callback_data) +{ + struct follow_event **followers; + struct follow_event *follower; + struct follow_event follow; + int *nr_followers; + + follow.event = NULL; + follow.callback = callback; + follow.callback_data = callback_data; + + if (instance) { + followers = &instance->missed_followers; + nr_followers = &instance->nr_missed_followers; + } else { + followers = &root_missed_followers; + nr_followers = &nr_root_missed_followers; + } + follower = realloc(*followers, sizeof(*follower) * + ((*nr_followers) + 1)); + if (!follower) + return -1; + + *followers = follower; + follower[(*nr_followers)++] = follow; + + return 0; +} + +static int call_missed_events(struct tracefs_instance *instance, + struct tep_event *event, struct tep_record *record, int cpu) +{ + struct follow_event *followers; + int nr_followers; + int ret = 0; + int i; + + if (instance) { + followers = instance->missed_followers; + nr_followers = instance->nr_missed_followers; + } else { + followers = root_missed_followers; + nr_followers = nr_root_missed_followers; + } + + if (!followers) + return 0; + + for (i = 0; i < nr_followers; i++) { + ret |= followers[i].callback(event, record, + cpu, followers[i].callback_data); + } + + return ret; +} + +static int call_followers(struct tracefs_instance *instance, + struct tep_event *event, struct tep_record *record, int cpu) +{ + struct follow_event *followers; + int nr_followers; + int ret = 0; + int i; + + if (record->missed_events) + ret = call_missed_events(instance, event, record, cpu); + if (ret) + return ret; + + if (instance) { + followers = instance->followers; + nr_followers = instance->nr_followers; + } else { + followers = root_followers; + nr_followers = nr_root_followers; + } + + if (!followers) + return 0; + + for (i = 0; i < nr_followers; i++) { + if (followers[i].event == event) + ret |= followers[i].callback(event, record, + cpu, followers[i].callback_data); + } + + return ret; +} + +static int read_cpu_pages(struct tep_handle *tep, struct tracefs_instance *instance, + struct cpu_iterate *cpus, int count, + int (*callback)(struct tep_event *, + struct tep_record *, + int, void *), + void *callback_context, + bool *keep_going) +{ + bool has_data = false; + int ret; + int i, j; + + for (i = 0; i < count; i++) { + ret = read_next_record(tep, cpus + i); + if (!ret) + has_data = true; + } + + while (has_data && *(volatile bool *)keep_going) { + j = count; + for (i = 0; i < count; i++) { + if (!cpus[i].event) + continue; + if (j == count || cpus[j].record.ts > cpus[i].record.ts) + j = i; + } + if (j < count) { + if (call_followers(instance, cpus[j].event, &cpus[j].record, cpus[j].cpu)) + break; + if (callback && + callback(cpus[j].event, &cpus[j].record, cpus[j].cpu, callback_context)) + break; + cpus[j].event = NULL; + read_next_record(tep, cpus + j); + } else { + has_data = false; + } + } + + return 0; +} + +static int open_cpu_files(struct tracefs_instance *instance, cpu_set_t *cpus, + int cpu_size, struct cpu_iterate **all_cpus, int *count) +{ + struct tracefs_cpu *tcpu; + struct cpu_iterate *tmp; + int nr_cpus; + int cpu; + int i = 0; + + *all_cpus = NULL; + + nr_cpus = sysconf(_SC_NPROCESSORS_CONF); + for (cpu = 0; cpu < nr_cpus; cpu++) { + if (cpus && !CPU_ISSET_S(cpu, cpu_size, cpus)) + continue; + tcpu = tracefs_cpu_open(instance, cpu, true); + tmp = realloc(*all_cpus, (i + 1) * sizeof(*tmp)); + if (!tmp) { + i--; + goto error; + } + + *all_cpus = tmp; + + memset(tmp + i, 0, sizeof(*tmp)); + + if (!tcpu) + goto error; + + tmp[i].tcpu = tcpu; + tmp[i].cpu = cpu; + tmp[i].psize = tracefs_cpu_read_size(tcpu); + tmp[i].page = malloc(tmp[i].psize); + + if (!tmp[i++].page) + goto error; + } + *count = i; + return 0; + error: + tmp = *all_cpus; + for (; i >= 0; i--) { + tracefs_cpu_close(tmp[i].tcpu); + free(tmp[i].page); + } + free(tmp); + *all_cpus = NULL; + return -1; +} + +/** + * tracefs_follow_event - Add callback for specific events for iterators + * @tep: a handle to the trace event parser context + * @instance: The instance to follow + * @system: The system of the event to track + * @event_name: The name of the event to track + * @callback: The function to call when the event is hit in an iterator + * @callback_data: The data to pass to @callback + * + * This attaches a callback to an @instance or the root instance if @instance + * is NULL, where if tracefs_iterate_raw_events() is called, that if the specified + * event is hit, it will call @callback, with the following parameters: + * @event: The event pointer that was found by @system and @event_name. + * @record; The event instance of @event. + * @cpu: The cpu that the event happened on. + * @callback_data: The same as @callback_data passed to the function. + * + * Returns 0 on success and -1 on error. + */ +int tracefs_follow_event(struct tep_handle *tep, struct tracefs_instance *instance, + const char *system, const char *event_name, + int (*callback)(struct tep_event *, + struct tep_record *, + int, void *), + void *callback_data) +{ + struct follow_event **followers; + struct follow_event *follower; + struct follow_event follow; + int *nr_followers; + + if (!tep) { + errno = EINVAL; + return -1; + } + + follow.event = tep_find_event_by_name(tep, system, event_name); + if (!follow.event) { + errno = ENOENT; + return -1; + } + + follow.callback = callback; + follow.callback_data = callback_data; + + if (instance) { + followers = &instance->followers; + nr_followers = &instance->nr_followers; + } else { + followers = &root_followers; + nr_followers = &nr_root_followers; + } + follower = realloc(*followers, sizeof(*follower) * + ((*nr_followers) + 1)); + if (!follower) + return -1; + + *followers = follower; + follower[(*nr_followers)++] = follow; + + return 0; +} + +static bool top_iterate_keep_going; + +/* + * tracefs_iterate_raw_events - Iterate through events in trace_pipe_raw, + * per CPU trace buffers + * @tep: a handle to the trace event parser context + * @instance: ftrace instance, can be NULL for the top instance + * @cpus: Iterate only through the buffers of CPUs, set in the mask. + * If NULL, iterate through all CPUs. + * @cpu_size: size of @cpus set + * @callback: A user function, called for each record from the file + * @callback_context: A custom context, passed to the user callback function + * + * If the @callback returns non-zero, the iteration stops - in that case all + * records from the current page will be lost from future reads + * The events are iterated in sorted order, oldest first. + * + * Returns -1 in case of an error, or 0 otherwise + */ +int tracefs_iterate_raw_events(struct tep_handle *tep, + struct tracefs_instance *instance, + cpu_set_t *cpus, int cpu_size, + int (*callback)(struct tep_event *, + struct tep_record *, + int, void *), + void *callback_context) +{ + bool *keep_going = instance ? &instance->iterate_keep_going : + &top_iterate_keep_going; + struct follow_event *followers; + struct cpu_iterate *all_cpus; + int count = 0; + int ret; + int i; + + (*(volatile bool *)keep_going) = true; + + if (!tep) + return -1; + + if (instance) + followers = instance->followers; + else + followers = root_followers; + if (!callback && !followers) + return -1; + + ret = open_cpu_files(instance, cpus, cpu_size, &all_cpus, &count); + if (ret < 0) + goto out; + ret = read_cpu_pages(tep, instance, all_cpus, count, + callback, callback_context, + keep_going); + +out: + if (all_cpus) { + for (i = 0; i < count; i++) { + kbuffer_free(all_cpus[i].kbuf); + tracefs_cpu_close(all_cpus[i].tcpu); + free(all_cpus[i].page); + } + free(all_cpus); + } + + return ret; +} + +/** + * tracefs_iterate_stop - stop the iteration over the raw events. + * @instance: ftrace instance, can be NULL for top tracing instance. + */ +void tracefs_iterate_stop(struct tracefs_instance *instance) +{ + if (instance) + instance->iterate_keep_going = false; + else + top_iterate_keep_going = false; +} + +static int add_list_string(char ***list, const char *name) +{ + char **tmp; + + tmp = tracefs_list_add(*list, name); + if (!tmp) { + tracefs_list_free(*list); + *list = NULL; + return -1; + } + + *list = tmp; + return 0; +} + +__hidden char *trace_append_file(const char *dir, const char *name) +{ + char *file; + int ret; + + ret = asprintf(&file, "%s/%s", dir, name); + + return ret < 0 ? NULL : file; +} + +static int event_file(char **path, const char *system, + const char *event, const char *file) +{ + if (!system || !event || !file) + return -1; + + return asprintf(path, "events/%s/%s/%s", + system, event, file); +} + +/** + * tracefs_event_get_file - return a file in an event directory + * @instance: The instance the event is in (NULL for top level) + * @system: The system name that the event file is in + * @event: The event name of the event + * @file: The name of the file in the event directory. + * + * Returns a path to a file in the event director. + * or NULL on error. The path returned must be freed with + * tracefs_put_tracing_file(). + */ +char *tracefs_event_get_file(struct tracefs_instance *instance, + const char *system, const char *event, + const char *file) +{ + char *instance_path; + char *path; + int ret; + + ret = event_file(&path, system, event, file); + if (ret < 0) + return NULL; + + instance_path = tracefs_instance_get_file(instance, path); + free(path); + + return instance_path; +} + +/** + * tracefs_event_file_read - read the content from an event file + * @instance: The instance the event is in (NULL for top level) + * @system: The system name that the event file is in + * @event: The event name of the event + * @file: The name of the file in the event directory. + * @psize: the size of the content read. + * + * Reads the content of the event file that is passed via the + * arguments and returns the content. + * + * Return a string containing the content of the file or NULL + * on error. The string returned must be freed with free(). + */ +char *tracefs_event_file_read(struct tracefs_instance *instance, + const char *system, const char *event, + const char *file, int *psize) +{ + char *content; + char *path; + int ret; + + ret = event_file(&path, system, event, file); + if (ret < 0) + return NULL; + + content = tracefs_instance_file_read(instance, path, psize); + free(path); + return content; +} + +/** + * tracefs_event_file_write - write to an event file + * @instance: The instance the event is in (NULL for top level) + * @system: The system name that the event file is in + * @event: The event name of the event + * @file: The name of the file in the event directory. + * @str: The string to write into the file + * + * Writes the content of @str to a file in the instance directory. + * The content of the file will be overwritten by @str. + * + * Return 0 on success, and -1 on error. + */ +int tracefs_event_file_write(struct tracefs_instance *instance, + const char *system, const char *event, + const char *file, const char *str) +{ + char *path; + int ret; + + ret = event_file(&path, system, event, file); + if (ret < 0) + return -1; + + ret = tracefs_instance_file_write(instance, path, str); + free(path); + return ret; +} + +/** + * tracefs_event_file_append - write to an event file + * @instance: The instance the event is in (NULL for top level) + * @system: The system name that the event file is in + * @event: The event name of the event + * @file: The name of the file in the event directory. + * @str: The string to write into the file + * + * Writes the content of @str to a file in the instance directory. + * The content of @str will be appended to the content of the file. + * The current content should not be lost. + * + * Return 0 on success, and -1 on error. + */ +int tracefs_event_file_append(struct tracefs_instance *instance, + const char *system, const char *event, + const char *file, const char *str) +{ + char *path; + int ret; + + ret = event_file(&path, system, event, file); + if (ret < 0) + return -1; + + ret = tracefs_instance_file_append(instance, path, str); + free(path); + return ret; +} + +/** + * tracefs_event_file_clear - clear an event file + * @instance: The instance the event is in (NULL for top level) + * @system: The system name that the event file is in + * @event: The event name of the event + * @file: The name of the file in the event directory. + * + * Clears the content of the event file. That is, it is opened + * with O_TRUNC and then closed. + * + * Return 0 on success, and -1 on error. + */ +int tracefs_event_file_clear(struct tracefs_instance *instance, + const char *system, const char *event, + const char *file) +{ + char *path; + int ret; + + ret = event_file(&path, system, event, file); + if (ret < 0) + return -1; + + ret = tracefs_instance_file_clear(instance, path); + free(path); + return ret; +} + +/** + * tracefs_event_file_exits - test if a file exists + * @instance: The instance the event is in (NULL for top level) + * @system: The system name that the event file is in + * @event: The event name of the event + * @file: The name of the file in the event directory. + * + * Return true if the file exists, false if it odes not or + * an error occurred. + */ +bool tracefs_event_file_exists(struct tracefs_instance *instance, + const char *system, const char *event, + const char *file) +{ + char *path; + bool ret; + + if (event_file(&path, system, event, file) < 0) + return false; + + ret = tracefs_file_exists(instance, path); + free(path); + return ret; +} + +/** + * tracefs_event_systems - return list of systems for tracing + * @tracing_dir: directory holding the "events" directory + * if NULL, top tracing directory is used + * + * Returns an allocated list of system names. Both the names and + * the list must be freed with tracefs_list_free() + * The list returned ends with a "NULL" pointer + */ +char **tracefs_event_systems(const char *tracing_dir) +{ + struct dirent *dent; + char **systems = NULL; + char *events_dir; + struct stat st; + DIR *dir; + int ret; + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + if (!tracing_dir) + return NULL; + + events_dir = trace_append_file(tracing_dir, "events"); + if (!events_dir) + return NULL; + + /* + * Search all the directories in the events directory, + * and collect the ones that have the "enable" file. + */ + ret = stat(events_dir, &st); + if (ret < 0 || !S_ISDIR(st.st_mode)) + goto out_free; + + dir = opendir(events_dir); + if (!dir) + goto out_free; + + while ((dent = readdir(dir))) { + const char *name = dent->d_name; + char *enable; + char *sys; + + if (strcmp(name, ".") == 0 || + strcmp(name, "..") == 0) + continue; + + sys = trace_append_file(events_dir, name); + ret = stat(sys, &st); + if (ret < 0 || !S_ISDIR(st.st_mode)) { + free(sys); + continue; + } + + enable = trace_append_file(sys, "enable"); + + ret = stat(enable, &st); + if (ret >= 0) { + if (add_list_string(&systems, name) < 0) + goto out_free; + } + free(enable); + free(sys); + } + + closedir(dir); + + out_free: + free(events_dir); + return systems; +} + +/** + * tracefs_system_events - return list of events for system + * @tracing_dir: directory holding the "events" directory + * @system: the system to return the events for + * + * Returns an allocated list of event names. Both the names and + * the list must be freed with tracefs_list_free() + * The list returned ends with a "NULL" pointer + */ +char **tracefs_system_events(const char *tracing_dir, const char *system) +{ + struct dirent *dent; + char **events = NULL; + char *system_dir = NULL; + struct stat st; + DIR *dir; + int ret; + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + if (!tracing_dir || !system) + return NULL; + + asprintf(&system_dir, "%s/events/%s", tracing_dir, system); + if (!system_dir) + return NULL; + + ret = stat(system_dir, &st); + if (ret < 0 || !S_ISDIR(st.st_mode)) + goto out_free; + + dir = opendir(system_dir); + if (!dir) + goto out_free; + + while ((dent = readdir(dir))) { + const char *name = dent->d_name; + char *event; + + if (strcmp(name, ".") == 0 || + strcmp(name, "..") == 0) + continue; + + event = trace_append_file(system_dir, name); + ret = stat(event, &st); + if (ret < 0 || !S_ISDIR(st.st_mode)) { + free(event); + continue; + } + + if (add_list_string(&events, name) < 0) + goto out_free; + + free(event); + } + + closedir(dir); + + out_free: + free(system_dir); + + return events; +} + +/** + * tracefs_tracers - returns an array of available tracers + * @tracing_dir: The directory that contains the tracing directory + * + * Returns an allocate list of plugins. The array ends with NULL + * Both the plugin names and array must be freed with tracefs_list_free() + */ +char **tracefs_tracers(const char *tracing_dir) +{ + char *available_tracers; + struct stat st; + char **plugins = NULL; + char *buf; + char *str, *saveptr; + char *plugin; + int slen; + int len; + int ret; + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + if (!tracing_dir) + return NULL; + + available_tracers = trace_append_file(tracing_dir, "available_tracers"); + if (!available_tracers) + return NULL; + + ret = stat(available_tracers, &st); + if (ret < 0) + goto out_free; + + len = str_read_file(available_tracers, &buf, true); + if (len <= 0) + goto out_free; + + for (str = buf; ; str = NULL) { + plugin = strtok_r(str, " ", &saveptr); + if (!plugin) + break; + slen = strlen(plugin); + if (!slen) + continue; + + /* chop off any newlines */ + if (plugin[slen - 1] == '\n') + plugin[slen - 1] = '\0'; + + /* Skip the non tracers */ + if (strcmp(plugin, "nop") == 0 || + strcmp(plugin, "none") == 0) + continue; + + if (add_list_string(&plugins, plugin) < 0) + break; + } + free(buf); + + out_free: + free(available_tracers); + + return plugins; +} + +static int load_events(struct tep_handle *tep, + const char *tracing_dir, const char *system, bool check) +{ + int ret = 0, failure = 0; + char **events = NULL; + struct stat st; + int len = 0; + int i; + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + events = tracefs_system_events(tracing_dir, system); + if (!events) + return -ENOENT; + + for (i = 0; events[i]; i++) { + char *format; + char *buf; + + ret = asprintf(&format, "%s/events/%s/%s/format", + tracing_dir, system, events[i]); + if (ret < 0) { + failure = -ENOMEM; + break; + } + + ret = stat(format, &st); + if (ret < 0) + goto next_event; + + /* check if event is already added, to avoid duplicates */ + if (check && tep_find_event_by_name(tep, system, events[i])) + goto next_event; + + len = str_read_file(format, &buf, true); + if (len <= 0) + goto next_event; + + ret = tep_parse_event(tep, buf, len, system); + free(buf); +next_event: + free(format); + if (ret) + failure = ret; + } + + tracefs_list_free(events); + return failure; +} + +__hidden int trace_rescan_events(struct tep_handle *tep, + const char *tracing_dir, const char *system) +{ + /* ToDo: add here logic for deleting removed events from tep handle */ + return load_events(tep, tracing_dir, system, true); +} + +__hidden int trace_load_events(struct tep_handle *tep, + const char *tracing_dir, const char *system) +{ + return load_events(tep, tracing_dir, system, false); +} + +__hidden struct tep_event *get_tep_event(struct tep_handle *tep, + const char *system, const char *name) +{ + struct tep_event *event; + + /* Check if event exists in the system */ + if (!tracefs_event_file_exists(NULL, system, name, "format")) + return NULL; + + /* If the event is already loaded in the tep, return it */ + event = tep_find_event_by_name(tep, system, name); + if (event) + return event; + + /* Try to load any new events from the given system */ + if (trace_rescan_events(tep, NULL, system)) + return NULL; + + return tep_find_event_by_name(tep, system, name); +} + +static int read_header(struct tep_handle *tep, const char *tracing_dir) +{ + struct stat st; + char *header; + char *buf; + int len; + int ret = -1; + + header = trace_append_file(tracing_dir, "events/header_page"); + + ret = stat(header, &st); + if (ret < 0) + goto out; + + len = str_read_file(header, &buf, true); + if (len <= 0) + goto out; + + tep_parse_header_page(tep, buf, len, sizeof(long)); + + free(buf); + + ret = 0; + out: + free(header); + return ret; +} + +static bool contains(const char *name, const char * const *names) +{ + if (!names) + return false; + for (; *names; names++) + if (strcmp(name, *names) == 0) + return true; + return false; +} + +static void load_kallsyms(struct tep_handle *tep) +{ + char *buf; + + if (str_read_file("/proc/kallsyms", &buf, false) <= 0) + return; + + tep_parse_kallsyms(tep, buf); + free(buf); +} + +static int load_saved_cmdlines(const char *tracing_dir, + struct tep_handle *tep, bool warn) +{ + char *path; + char *buf; + int ret; + + path = trace_append_file(tracing_dir, "saved_cmdlines"); + if (!path) + return -1; + + ret = str_read_file(path, &buf, false); + free(path); + if (ret <= 0) + return -1; + + ret = tep_parse_saved_cmdlines(tep, buf); + free(buf); + + return ret; +} + +static void load_printk_formats(const char *tracing_dir, + struct tep_handle *tep) +{ + char *path; + char *buf; + int ret; + + path = trace_append_file(tracing_dir, "printk_formats"); + if (!path) + return; + + ret = str_read_file(path, &buf, false); + free(path); + if (ret <= 0) + return; + + tep_parse_printk_formats(tep, buf); + free(buf); +} + +/* + * Do a best effort attempt to load kallsyms, saved_cmdlines and + * printk_formats. If they can not be loaded, then this will not + * do the mappings. But this does not fail the loading of events. + */ +static void load_mappings(const char *tracing_dir, + struct tep_handle *tep) +{ + load_kallsyms(tep); + + /* If there's no tracing_dir no reason to go further */ + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + if (!tracing_dir) + return; + + load_saved_cmdlines(tracing_dir, tep, false); + load_printk_formats(tracing_dir, tep); +} + +int tracefs_load_cmdlines(const char *tracing_dir, struct tep_handle *tep) +{ + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + if (!tracing_dir) + return -1; + + return load_saved_cmdlines(tracing_dir, tep, true); +} + +static int fill_local_events_system(const char *tracing_dir, + struct tep_handle *tep, + const char * const *sys_names, + int *parsing_failures) +{ + char **systems = NULL; + int ret; + int i; + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + if (!tracing_dir) + return -1; + + systems = tracefs_event_systems(tracing_dir); + if (!systems) + return -1; + + ret = read_header(tep, tracing_dir); + if (ret < 0) { + ret = -1; + goto out; + } + + if (parsing_failures) + *parsing_failures = 0; + + for (i = 0; systems[i]; i++) { + if (sys_names && !contains(systems[i], sys_names)) + continue; + ret = trace_load_events(tep, tracing_dir, systems[i]); + if (ret && parsing_failures) + (*parsing_failures)++; + } + + /* Include ftrace, as it is excluded for not having "enable" file */ + if (!sys_names || contains("ftrace", sys_names)) + trace_load_events(tep, tracing_dir, "ftrace"); + + load_mappings(tracing_dir, tep); + + /* always succeed because parsing failures are not critical */ + ret = 0; +out: + tracefs_list_free(systems); + return ret; +} + +static void set_tep_cpus(const char *tracing_dir, struct tep_handle *tep) +{ + struct stat st; + char path[PATH_MAX]; + int cpus = sysconf(_SC_NPROCESSORS_CONF); + int max_cpu = 0; + int ret; + int i; + + if (!tracing_dir) + tracing_dir = tracefs_tracing_dir(); + + /* + * Paranoid: in case sysconf() above does not work. + * And we also only care about the number of tracing + * buffers that exist. If cpus is 32, but the top half + * is offline, there may only be 16 tracing buffers. + * That's what we want to know. + */ + for (i = 0; !cpus || i < cpus; i++) { + snprintf(path, PATH_MAX, "%s/per_cpu/cpu%d", tracing_dir, i); + ret = stat(path, &st); + if (!ret && S_ISDIR(st.st_mode)) + max_cpu = i + 1; + else if (i >= cpus) + break; + } + + if (!max_cpu) + max_cpu = cpus; + + tep_set_cpus(tep, max_cpu); +} + +/** + * tracefs_local_events_system - create a tep from the events of the specified subsystem. + * + * @tracing_dir: The directory that contains the events. + * @sys_name: Array of system names, to load the events from. + * The last element from the array must be NULL + * + * Returns a tep structure that contains the tep local to + * the system. + */ +struct tep_handle *tracefs_local_events_system(const char *tracing_dir, + const char * const *sys_names) +{ + struct tep_handle *tep = NULL; + + tep = tep_alloc(); + if (!tep) + return NULL; + + if (fill_local_events_system(tracing_dir, tep, sys_names, NULL)) { + tep_free(tep); + tep = NULL; + } + + set_tep_cpus(tracing_dir, tep); + + /* Set the long size for this tep handle */ + tep_set_long_size(tep, tep_get_header_page_size(tep)); + + return tep; +} + +/** + * tracefs_local_events - create a tep from the events on system + * @tracing_dir: The directory that contains the events. + * + * Returns a tep structure that contains the teps local to + * the system. + */ +struct tep_handle *tracefs_local_events(const char *tracing_dir) +{ + return tracefs_local_events_system(tracing_dir, NULL); +} + +/** + * tracefs_fill_local_events - Fill a tep with the events on system + * @tracing_dir: The directory that contains the events. + * @tep: Allocated tep handler which will be filled + * @parsing_failures: return number of failures while parsing the event files + * + * Returns whether the operation succeeded + */ +int tracefs_fill_local_events(const char *tracing_dir, + struct tep_handle *tep, int *parsing_failures) +{ + return fill_local_events_system(tracing_dir, tep, + NULL, parsing_failures); +} + +static bool match(const char *str, regex_t *re) +{ + return regexec(re, str, 0, NULL, 0) == 0; +} + +enum event_state { + STATE_INIT, + STATE_ENABLED, + STATE_DISABLED, + STATE_MIXED, + STATE_ERROR, +}; + +static int read_event_state(struct tracefs_instance *instance, const char *file, + enum event_state *state) +{ + char *val; + int ret = 0; + + if (*state == STATE_ERROR) + return -1; + + val = tracefs_instance_file_read(instance, file, NULL); + if (!val) + return -1; + + switch (val[0]) { + case '0': + switch (*state) { + case STATE_INIT: + *state = STATE_DISABLED; + break; + case STATE_ENABLED: + *state = STATE_MIXED; + break; + default: + break; + } + break; + case '1': + switch (*state) { + case STATE_INIT: + *state = STATE_ENABLED; + break; + case STATE_DISABLED: + *state = STATE_MIXED; + break; + default: + break; + } + break; + case 'X': + *state = STATE_MIXED; + break; + default: + *state = TRACEFS_ERROR; + ret = -1; + break; + } + free(val); + + return ret; +} + +static int enable_disable_event(struct tracefs_instance *instance, + const char *system, const char *event, + bool enable, enum event_state *state) +{ + const char *str = enable ? "1" : "0"; + char *system_event; + int ret; + + ret = asprintf(&system_event, "events/%s/%s/enable", system, event); + if (ret < 0) + return ret; + + if (state) + ret = read_event_state(instance, system_event, state); + else + ret = tracefs_instance_file_write(instance, system_event, str); + free(system_event); + + return ret; +} + +static int enable_disable_system(struct tracefs_instance *instance, + const char *system, bool enable, + enum event_state *state) +{ + const char *str = enable ? "1" : "0"; + char *system_path; + int ret; + + ret = asprintf(&system_path, "events/%s/enable", system); + if (ret < 0) + return ret; + + if (state) + ret = read_event_state(instance, system_path, state); + else + ret = tracefs_instance_file_write(instance, system_path, str); + free(system_path); + + return ret; +} + +static int enable_disable_all(struct tracefs_instance *instance, + bool enable) +{ + const char *str = enable ? "1" : "0"; + int ret; + + ret = tracefs_instance_file_write(instance, "events/enable", str); + return ret < 0 ? ret : 0; +} + +static int make_regex(regex_t *re, const char *match) +{ + int len = strlen(match); + char str[len + 3]; + char *p = &str[0]; + + if (!len || match[0] != '^') + *(p++) = '^'; + + strcpy(p, match); + p += len; + + if (!len || match[len-1] != '$') + *(p++) = '$'; + + *p = '\0'; + + return regcomp(re, str, REG_ICASE|REG_NOSUB); +} + +static int event_enable_disable(struct tracefs_instance *instance, + const char *system, const char *event, + bool enable, enum event_state *state) +{ + regex_t system_re, event_re; + char **systems; + char **events = NULL; + int ret = -1; + int s, e; + + /* Handle all events first */ + if (!system && !event) + return enable_disable_all(instance, enable); + + systems = tracefs_event_systems(NULL); + if (!systems) + goto out_free; + + if (system) { + ret = make_regex(&system_re, system); + if (ret < 0) + goto out_free; + } + if (event) { + ret = make_regex(&event_re, event); + if (ret < 0) { + if (system) + regfree(&system_re); + goto out_free; + } + } + + ret = -1; + for (s = 0; systems[s]; s++) { + if (system && !match(systems[s], &system_re)) + continue; + + /* Check for the short cut first */ + if (!event) { + ret = enable_disable_system(instance, systems[s], enable, state); + if (ret < 0) + break; + ret = 0; + continue; + } + + events = tracefs_system_events(NULL, systems[s]); + if (!events) + continue; /* Error? */ + + for (e = 0; events[e]; e++) { + if (!match(events[e], &event_re)) + continue; + ret = enable_disable_event(instance, systems[s], + events[e], enable, state); + if (ret < 0) + break; + ret = 0; + } + tracefs_list_free(events); + events = NULL; + } + if (system) + regfree(&system_re); + if (event) + regfree(&event_re); + + out_free: + tracefs_list_free(systems); + tracefs_list_free(events); + return ret; +} + +/** + * tracefs_event_enable - enable specified events + * @instance: ftrace instance, can be NULL for the top instance + * @system: A regex of a system (NULL to match all systems) + * @event: A regex of the event in the system (NULL to match all events) + * + * This will enable events that match the @system and @event. + * If both @system and @event are NULL, then it will enable all events. + * If @system is NULL, it will look at all systems for matching events + * to @event. + * If @event is NULL, then it will enable all events in the systems + * that match @system. + * + * Returns 0 on success, and -1 if it encountered an error, + * or if no events matched. If no events matched, then -1 is set + * but errno will not be. + */ +int tracefs_event_enable(struct tracefs_instance *instance, + const char *system, const char *event) +{ + return event_enable_disable(instance, system, event, true, NULL); +} + +int tracefs_event_disable(struct tracefs_instance *instance, + const char *system, const char *event) +{ + return event_enable_disable(instance, system, event, false, NULL); +} + +/** + * tracefs_event_is_enabled - return if the event is enabled or not + * @instance: ftrace instance, can be NULL for the top instance + * @system: The name of the system to check + * @event: The name of the event to check + * + * Checks is an event or multiple events are enabled. + * + * If @system is NULL, then it will check all the systems where @event is + * a match. + * + * If @event is NULL, then it will check all events where @system is a match. + * + * If both @system and @event are NULL, then it will check all events + * + * Returns TRACEFS_ALL_ENABLED if all matching are enabled. + * Returns TRACEFS_SOME_ENABLED if some are enabled and some are not + * Returns TRACEFS_ALL_DISABLED if none of the events are enabled. + * Returns TRACEFS_ERROR if there is an error reading the events. + */ +enum tracefs_enable_state +tracefs_event_is_enabled(struct tracefs_instance *instance, + const char *system, const char *event) +{ + enum event_state state = STATE_INIT; + int ret; + + ret = event_enable_disable(instance, system, event, false, &state); + + if (ret < 0) + return TRACEFS_ERROR; + + switch (state) { + case STATE_ENABLED: + return TRACEFS_ALL_ENABLED; + case STATE_DISABLED: + return TRACEFS_ALL_DISABLED; + case STATE_MIXED: + return TRACEFS_SOME_ENABLED; + default: + return TRACEFS_ERROR; + } +} |