Provided by: libtracefs-doc_1.7.0-1_all 
NAME
libtracefs - Linux kernel trace file system library
SYNOPSIS
#include <tracefs.h>
Locations of tracing files and directories:
char *tracefs_get_tracing_file(const char *name);
void tracefs_put_tracing_file(char *name);
const char *tracefs_tracing_dir(void);
const char *tracefs_debug_dir(void);
int tracefs_set_tracing_dir(char *tracing_dir)
int tracefs_tracing_dir_is_mounted(bool mount, const char **path);
Trace instances:
struct tracefs_instance *tracefs_instance_create(const char *name);
int tracefs_instance_destroy(struct tracefs_instance *instance);
struct tracefs_instance *tracefs_instance_alloc(const char *tracing_dir, const char *name);
void tracefs_instance_free(struct tracefs_instance *instance);
char **tracefs_instances(const char *regex);
void tracefs_instance_reset(struct tracefs_instance *instance);
bool tracefs_instance_is_new(struct tracefs_instance *instance);
bool tracefs_file_exists(struct tracefs_instance *instance, char *name);
bool tracefs_dir_exists(struct tracefs_instance *instance, char *name);
char *tracefs_instance_get_file(struct tracefs_instance *instance, const char *file);
char *tracefs_instance_get_dir(struct tracefs_instance *instance);
int tracefs_instance_file_open(struct tracefs_instance *instance, const char *file, int mode);
int tracefs_instance_file_write(struct tracefs_instance *instance, const char *file, const char *str);
int tracefs_instance_file_append(struct tracefs_instance *instance, const char *file, const char *str);
int tracefs_instance_file_clear(struct tracefs_instance *instance, const char *file);
char *tracefs_instance_file_read(struct tracefs_instance *instance, const char *file, int *psize);
int tracefs_instance_file_read_number(struct tracefs_instance *instance, const char *file, long long int *res);
const char *tracefs_instance_get_name(struct tracefs_instance *instance);
const char *tracefs_instance_get_trace_dir(struct tracefs_instance *instance);
int tracefs_instances_walk(int (*callback)(const char *, void *), void *context);
bool tracefs_instance_exists(const char *name);
int tracefs_instance_set_affinity(struct tracefs_instance *instance, const char *cpu_str);
int tracefs_instance_set_affinity_set(struct tracefs_instance *instance, cpu_set_t *set, size_t set_size);
int tracefs_instance_set_affinity_raw(struct tracefs_instance *instance, const char *mask);
char *tracefs_instance_get_affinity(struct tracefs_instance *instance);
int tracefs_instance_get_affinity_set(struct tracefs_instance *instance, cpu_set_t *set, size_t set_size);
char *tracefs_instance_get_affinity_raw(struct tracefs_instance *instance);
size_t tracefs_instance_get_buffer_size(struct tracefs_instance *instance, int cpu);
int tracefs_instance_set_buffer_size(struct tracefs_instance *instance, size_t size, int cpu);
Trace events:
char **tracefs_event_systems(const char *tracing_dir);
char **tracefs_system_events(const char *tracing_dir, const char *system);
int tracefs_event_enable(struct tracefs_instance *instance, const char *system,
const char *event);
int tracefs_event_disable(struct tracefs_instance *instance, const char *system,
const char *event);
enum tracefs_enable_state tracefs_event_is_enabled(struct tracefs_instance *instance,
const char *system, const char *event);
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);
void tracefs_iterate_stop(struct tracefs_instance *instance);
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);
int tracefs_follow_missed_events(struct tracefs_instance *instance,
int (*callback)(struct tep_event *,
struct tep_record *,
int, void *),
void *callback_data);
struct tep_handle *tracefs_local_events(const char *tracing_dir);
struct tep_handle *tracefs_local_events_system(const char *tracing_dir, const char * const *sys_names);
int tracefs_fill_local_events(const char *tracing_dir, struct tep_handle *tep, int *parsing_failures);
int tracefs_load_cmdlines(const char *tracing_dir, struct tep_handle *tep);
char *tracefs_event_get_file(struct tracefs_instance *instance, const char *system, const char *event,
const char *file);
char *tracefs_event_file_read(struct tracefs_instance *instance, const char *system, const char *event,
const char *file, int *psize);
int tracefs_event_file_write(struct tracefs_instance *instance, const char *system, const char *event,
const char *file, const char *str);
int tracefs_event_file_append(struct tracefs_instance *instance, const char *system, const char *event,
const char *file, const char *str);
int tracefs_event_file_clear(struct tracefs_instance *instance, const char *system, const char *event,
const char *file);
bool tracefs_event_file_exists(struct tracefs_instance *instance, const char *system, const char *event,
Event filters:
int tracefs_filter_string_append(struct tep_event *event, char **filter,
struct tracefs_filter type, const char *field,
enum tracefs_synth_compare compare, const char *val);
int tracefs_filter_string_verify(struct tep_event *event, const char *filter, char **err);
int tracefs_event_filter_apply(struct tracefs_instance *instance, struct tep_event *event, const char *filter);
int tracefs_event_filter_clear(struct tracefs_instance *instance, struct tep_event *event);
Function filters:
int tracefs_function_filter(struct tracefs_instance *instance, const char *filter, const char *module, int flags);
int tracefs_function_notrace(struct tracefs_instance *instance, const char *filter, const char *module, int flags);
int tracefs_filter_functions(const char *filter, const char *module, char ***list);
Trace helper functions:
void tracefs_list_free(char **list);
char **tracefs_list_add(char *list, const char *string);
int *tracefs_list_size(char **list);
char *tracefs_get_clock(struct tracefs_instance *instance);
int tracefs_trace_is_on(struct tracefs_instance *instance);
int tracefs_trace_on(struct tracefs_instance *instance);
int tracefs_trace_off(struct tracefs_instance *instance);
int tracefs_trace_on_get_fd(struct tracefs_instance *instance);
int tracefs_trace_on_fd(int fd);
int tracefs_trace_off_fd(int fd);
Trace stream:
ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int flags);
ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags);
void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
Trace options:
const struct tracefs_options_mask *tracefs_options_get_supported(struct tracefs_instance *instance);
bool tracefs_option_is_supported(struct tracefs_instance *instance, enum tracefs_option_id id);
const struct tracefs_options_mask *tracefs_options_get_enabled(struct tracefs_instance *instance);
bool tracefs_option_is_enabled(struct tracefs_instance *instance, enum tracefs_option_id id);
bool tracefs_option_mask_is_set(const struct tracefs_options_mask options, enum tracefs_option_id id);
int *tracefs_option_enable(struct tracefs_instance *instance, enum tracefs_option_id id);
int tracefs_option_disable(struct tracefs_instance *instance, enum tracefs_option_id id);
const char *tracefs_option_name(enum tracefs_option_id id);
enum tracefs_option_id tracefs_option_id(const char *name);
Ftrace tracers:
char **tracefs_tracers(const char *tracing_dir);
char ** tracefs_instance_tracers(struct tracefs_instance *instance);
bool tracefs_tracer_available(const char *tracing_dir, const char *tracer);
int tracefs_tracer_set(struct tracefs_instance *instance, enum tracefs_tracers tracer);
int tracefs_tracer_set(struct tracefs_instance *instance, enum tracefs_tracers tracer, const char *name);
int tracefs_tracer_clear(struct tracefs_instance *instance);
Writing data in the trace buffer:
int tracefs_print_init(struct tracefs_instance *instance);
int tracefs_printf(struct tracefs_instance *instance, const char *fmt, ...);
int tracefs_vprintf(struct tracefs_instance *instance, const char *fmt, va_list ap);
void tracefs_print_close(struct tracefs_instance *instance);
int tracefs_binary_init(struct tracefs_instance *instance);
int tracefs_binary_write(struct tracefs_instance *instance, void *data, int len);
void tracefs_binary_close(struct tracefs_instance *instance);
Control library logs:
int tracefs_set_loglevel(enum tep_loglevel level);
Dynamic event generic APIs:
struct tracefs_dynevent;
enum tracefs_dynevent_type;
int tracefs_dynevent_create(struct tracefs_dynevent *devent);
int tracefs_dynevent_destroy(struct tracefs_dynevent *devent, bool force);
int tracefs_dynevent_destroy_all(unsigned int types, bool force);
void tracefs_dynevent_free(struct tracefs_dynevent *devent);
void tracefs_dynevent_list_free(struct tracefs_dynevent **events);
struct tracefs_dynevent *tracefs_dynevent_get(enum tracefs_dynevent_type type, const char *system, const char *event);
struct tracefs_dynevent **tracefs_dynevent_get_all(unsigned int types, const char *system);
enum tracefs_dynevent_type tracefs_dynevent_info(struct tracefs_dynevent *dynevent, char **system, char **event, char **prefix, char **addr, char **format);
struct tep_event *tracefs_dynevent_get_event(struct tep_handle *tep, struct tracefs_dynevent *dynevent);
Even probes (eprobes):
struct tracefs_dynevent * tracefs_eprobe_alloc(const char *system, const char *event, const char *target_system, const char *target_event, const char *fetchargs);
Uprobes, Kprobes and Kretprobes:
struct tracefs_dynevent * tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format);
struct tracefs_dynevent * tracefs_kretprobe_alloc(const char *system, const char *event, const char *addr, const char *format, unsigned int max);
int tracefs_kprobe_raw(const char *system, const char *event, const char *addr, const char *format);
int tracefs_kretprobe_raw(const char *system, const char *event, const char *addr, const char *format);
tracefs_uprobe_alloc(const char *system, const char *event,
const char *file, unsigned long long offset, const char *fetchargs)
tracefs_uretprobe_alloc(const char *system, const char *event,
const char *file, unsigned long long offset, const char *fetchargs);
int tracefs_kprobe_destroy(const char *system, const char *event,
const char *addr, const char *format, bool force);
Synthetic events:
struct tracefs_synth *tracefs_sql(struct tep_handle *tep, const char *name,
const char *sql_buffer, char **err);
struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
const char *name,
const char *start_system,
const char *start_event,
const char *end_system,
const char *end_event,
const char *start_match_field,
const char *end_match_field,
const char *match_name);
int tracefs_synth_add_match_field(struct tracefs_synth *synth,
const char *start_match_field,
const char *end_match_field,
const char *name);
int tracefs_synth_add_compare_field(struct tracefs_synth *synth,
const char *start_compare_field,
const char *end_compare_field,
enum tracefs_synth_calc calc,
const char *name);
int tracefs_synth_add_start_field(struct tracefs_synth *synth,
const char *start_field,
const char *name);
int tracefs_synth_add_end_field(struct tracefs_synth *synth,
const char *end_field,
const char *name);
int tracefs_synth_append_start_filter(struct tracefs_synth *synth,
struct tracefs_filter type,
const char *field,
enum tracefs_synth_compare compare,
const char *val);
int tracefs_synth_append_end_filter(struct tracefs_synth *synth,
struct tracefs_filter type,
const char *field,
enum tracefs_synth_compare compare,
const char *val);
void tracefs_synth_free(struct tracefs_synth *synth);
int tracefs_synth_create(struct tracefs_synth *synth);
int tracefs_synth_destroy(struct tracefs_synth *synth);
int tracefs_synth_set_instance(struct tracefs_synth *synth, struct tracefs_instance *instance);
int tracefs_synth_echo_cmd(struct trace_seq *seq, struct tracefs_synth *synth);
bool tracefs_synth_complete(struct tracefs_synth *synth);
struct tracefs_hist *tracefs_synth_get_start_hist(struct tracefs_synth *synth);
int tracefs_synth_trace(struct tracefs_synth *synth,
enum tracefs_synth_handler type, const char *var);
int tracefs_synth_snapshot(struct tracefs_synth *synth,
enum tracefs_synth_handler type, const char *var);
int tracefs_synth_save(struct tracefs_synth *synth,
enum tracefs_synth_handler type, const char *var,
char **save_fields);
const char *tracefs_synth_get_name(struct tracefs_synth *synth);
int tracefs_synth_raw_fmt(struct trace_seq *seq, struct tracefs_synth *synth);
const char *tracefs_synth_show_event(struct tracefs_synth *synth);
const char *tracefs_synth_show_start_hist(struct tracefs_synth *synth);
const char *tracefs_synth_show_end_hist(struct tracefs_synth *synth);
struct tep_event *tracefs_synth_get_event(struct tep_handle *tep, struct tracefs_synth *synth);
Ftrace errors reporting:
char *tracefs_error_last(struct tracefs_instance *instance);
char *tracefs_error_all(struct tracefs_instance *instance);
int tracefs_error_clear(struct tracefs_instance *instance);
Histograms:
struct tracefs_hist *tracefs_hist_alloc(struct tracefs_tep * tep,
const char *system, const char *event,
const char *key, enum tracefs_hist_key_type type);
struct tracefs_hist *tracefs_hist_alloc_2d(struct tracefs_tep * tep,
const char *system, const char *event,
const char *key1, enum tracefs_hist_key_type type1,
const char *key2, enum tracefs_hist_key_type type2));
struct tracefs_hist *tracefs_hist_alloc_nd(struct tracefs_tep * tep,
const char *system, const char *event,
struct tracefs_hist_axis *axes);
struct tracefs_hist *tracefs_hist_alloc_nd_cnt(struct tep_handle *tep,
const char *system, const char *event_name,
struct tracefs_hist_axis_cnt *axes);
void tracefs_hist_free(struct tracefs_hist *hist);
int tracefs_hist_add_key(struct tracefs_hist *hist, const char *key,
enum tracefs_hist_key_type type);
int tracefs_hist_add_key_cnt(struct tracefs_hist *hist, const char *key,
enum tracefs_hist_key_type type, int cnt);
int tracefs_hist_add_value(struct tracefs_hist *hist, const char *value);
int tracefs_hist_add_sort_key(struct tracefs_hist *hist,
const char *sort_key);
int tracefs_hist_set_sort_key(struct tracefs_hist *hist,
const char *sort_key, ...);
int tracefs_hist_sort_key_direction(struct tracefs_hist *hist,
const char *sort_key,
enum tracefs_hist_sort_direction dir);
int tracefs_hist_add_name(struct tracefs_hist *hist, const char *name);
int tracefs_hist_append_filter(struct tracefs_hist *hist,
enum tracefs_filter type,
const char *field,
enum tracefs_compare compare,
const char *val);
int tracefs_hist_echo_cmd(struct trace_seq *s, struct tracefs_instance *instance,
struct tracefs_hist *hist,
enum tracefs_hist_command command);
int tracefs_hist_command(struct tracefs_instance *instance,
struct tracefs_hist *hist,
enum tracefs_hist_command command);
const char *tracefs_hist_get_name(struct tracefs_hist *hist);
const char *tracefs_hist_get_event(struct tracefs_hist *hist);
const char *tracefs_hist_get_system(struct tracefs_hist *hist);
int tracefs_hist_start(struct tracefs_instance *instance, struct tracefs_hist *hist);
int tracefs_hist_destroy(struct tracefs_instance *instance, struct tracefs_hist *hist);
int tracefs_hist_pause(struct tracefs_instance *instance, struct tracefs_hist *hist);
int tracefs_hist_continue(struct tracefs_instance *instance, struct tracefs_hist *hist);
int tracefs_hist_reset(struct tracefs_instance *instance, struct tracefs_hist *hist);
Recording of trace_pipe_raw files:
struct tracefs_cpu *tracefs_cpu_open(struct tracefs_instance *instance,
int cpu, bool nonblock);
struct tracefs_cpu *tracefs_cpu_alloc_fd(int fd, int subbuf_size, bool nonblock);
void tracefs_cpu_close(struct tracefs_cpu *tcpu);
void tracefs_cpu_free_fd(struct tracefs_cpu *tcpu);
int tracefs_cpu_read_size(struct tracefs_cpu *tcpu);
int tracefs_cpu_read(struct tracefs_cpu *tcpu, void *buffer, bool nonblock);
int tracefs_cpu_buffered_read(struct tracefs_cpu *tcpu, void *buffer, bool nonblock);
int tracefs_cpu_write(struct tracefs_cpu *tcpu, int wfd, bool nonblock);
int tracefs_cpu_stop(struct tracefs_cpu *tcpu);
int tracefs_cpu_flush(struct tracefs_cpu *tcpu, void *buffer);
int tracefs_cpu_flush_write(struct tracefs_cpu *tcpu, int wfd);
int tracefs_cpu_pipe(struct tracefs_cpu *tcpu, int wfd, bool nonblock);
Helper functions for guest tracing:
char *tracefs_find_cid_pid(int cid);
char *tracefs_instance_find_cid_pid(struct tracefs_instance *instance, int cid);
int tracefs_time_conversion(int cpu, int *shift, int *multi, long long *offset);
DESCRIPTION
The libtracefs(3) library provides APIs to access kernel trace file system.
FILES
tracefs.h
Header file to include in order to have access to the library APIs.
-ltracefs
Linker switch to add when building a program that uses the library.
SEE ALSO
libtraceevent(3), trace-cmd(1)
AUTHOR
Steven Rostedt <rostedt@goodmis.org[1]>
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>
REPORTING BUGS
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
LICENSE
libtracefs is Free Software licensed under the GNU LGPL 2.1
RESOURCES
https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
COPYING
Copyright (C) 2020 VMware, Inc. Free use of this software is granted under the terms of
the GNU Public License (GPL).
NOTES
1. rostedt@goodmis.org
mailto:rostedt@goodmis.org
2. tz.stoyanov@gmail.com
mailto:tz.stoyanov@gmail.com
3. linux-trace-devel@vger.kernel.org
mailto:linux-trace-devel@vger.kernel.org