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LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)

NAME

libtraceevent - Linux kernel trace event library

SYNOPSIS

#include <event-parse.h>
Management of tep handler data structure and access of its members:

struct tep_handle *tep_alloc(void);
void tep_free(struct tep_handle *tep);
void tep_ref(struct tep_handle *tep);
void tep_unref(struct tep_handle *tep);
int tep_get_ref(struct tep_handle *tep);
void tep_set_flag(struct tep_handle *tep, enum tep_flag flag);
void tep_clear_flag(struct tep_handle *tep, enum tep_flag flag);
bool tep_test_flag(struct tep_handle *tep, enum tep_flag flags);
int tep_get_cpus(struct tep_handle *tep);
void tep_set_cpus(struct tep_handle *tep, int cpus);
int tep_get_long_size(strucqt tep_handle *tep);
void tep_set_long_size(struct tep_handle *tep, int long_size);
int tep_get_page_size(struct tep_handle *tep);
void tep_set_page_size(struct tep_handle *tep, int page_size);
int tep_get_sub_buffer_size(struct tep_handle *tep);
int tep_get_header_page_size(struct tep_handle *tep);
int tep_get_header_timestamp_size(struct tep_handle *tep);
bool tep_is_old_format(struct tep_handle *tep);
int tep_strerror(struct tep_handle *tep, enum tep_errno errnum, char *buf, size_t buflen); Register / unregister APIs:
int tep_register_function(struct tep_handle *tep, char *name, unsigned long long addr, char *mod);
int tep_register_event_handler(struct tep_handle *tep, int id, const char *sys_name, const char *event_name, tep_event_handler_func func, void *context);
int tep_unregister_event_handler(struct tep_handle *tep, int id, const char *sys_name, const char *event_name, tep_event_handler_func func, void *context);
int tep_register_print_string(struct tep_handle *tep, const char *fmt, unsigned long long addr);
int tep_register_print_function(struct tep_handle *tep, tep_func_handler func, enum tep_func_arg_type ret_type, char *name, ...);
int tep_unregister_print_function(struct tep_handle *tep, tep_func_handler func, char *name);
int tep_get_function_count(struct tep_handle tep); Trace printk parsing:
void *tep_print_printk(struct tep_handle *tep);
void tep_print_funcs(struct tep_handle *tep);
void tep_set_test_filters(struct tep_handle *tep, int test_filters);
void tep_plugin_print_options(struct trace_seq *s);
int tep_plugin_add_option(const char *name, const char *val); Meta data parsing:
int tep_parse_saved_cmdlines(struct tep_handle *tep, const char *buf);
int tep_parse_printk_formats(struct tep_handle *tep, const char *buf);
int tep_parse_kallsyms(struct tep_handle *tep, const char *buf); Plugins management:
struct tep_plugin_list *tep_load_plugins(struct tep_handle *tep);
void tep_unload_plugins(struct tep_plugin_list *plugin_list, struct tep_handle *tep);
char **tep_plugin_list_options(void);
void tep_plugin_free_options_list(char **list);
int tep_plugin_add_options(const char *name, struct tep_plugin_option *options);
void tep_plugin_remove_options(struct tep_plugin_option *options);
void tep_print_plugins(struct trace_seq *s, const char *prefix, const char *suffix, const struct tep_plugin_list *list);
void tep_load_plugins_hook(struct tep_handle *tep, const char *suffix,
void (*load_plugin)(struct tep_handle *tep,
const char *path,
const char *name,
void *data),
void *data);
int tep_add_plugin_path(struct tep_handle *tep, char *path,
enum tep_plugin_load_priority prio); Event related APIs:
struct tep_event *tep_get_event(struct tep_handle *tep, int index);
struct tep_event *tep_get_first_event(struct tep_handle *tep);
int tep_get_events_count(struct tep_handle *tep);
struct tep_event **tep_list_events(struct tep_handle *tep, enum tep_event_sort_type sort_type);
struct tep_event **tep_list_events_copy(struct tep_handle *tep, enum tep_event_sort_type sort_type);
void tep_print_event(struct tep_handle *tep, struct trace_seq *s, struct tep_record *record, const char *fmt, ...); Event finding:
struct tep_event *tep_find_event(struct tep_handle *tep, int id);
struct tep_event *tep_find_event_by_name(struct tep_handle *tep, const char *sys, const char *name);
struct tep_event *tep_find_event_by_record(struct tep_handle *tep, struct tep_record *record); Parsing of event files:
int tep_parse_header_page(struct tep_handle *tep, char *buf, unsigned long size, int long_size);
enum tep_errno tep_parse_event(struct tep_handle *tep, const char *buf, unsigned long size, const char *sys);
enum tep_errno tep_parse_format(struct tep_handle *tep, struct tep_event **eventp, const char *buf, unsigned long size, const char *sys); APIs related to fields from event’s format files:
struct tep_format_field **tep_event_common_fields(struct tep_event *event);
struct tep_format_field **tep_event_fields(struct tep_event *event);
void *tep_get_field_raw(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, int *len, int err);
int tep_get_field_val(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, unsigned long long *val, int err);
int tep_get_common_field_val(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, unsigned long long *val, int err);
int tep_get_any_field_val(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, unsigned long long *val, int err);
int tep_read_number_field(struct tep_format_field *field, const void *data, unsigned long long *value); Event fields printing:
void tep_print_field_content(struct trace_seq *s, void *data, int size, struct tep_format_field *field);
void tep_print_fields(struct trace_seq *s, void *data, int size, struct tep_event *event);
int tep_print_num_field(struct trace_seq *s, const char *fmt, struct tep_event *event, const char *name, struct tep_record *record, int err);
int tep_print_func_field(struct trace_seq *s, const char *fmt, struct tep_event *event, const char *name, struct tep_record *record, int err);
void tep_record_print_fields(struct trace_seq *s, struct tep_record *record, struct tep_event *event);
void tep_record_print_selected_fields(struct trace_seq *s, struct tep_record *record, struct tep_event *event, int select_mask); Event fields finding:
struct tep_format_field *tep_find_common_field(struct tep_event *event, const char *name);
struct tep_format_field *tep_find_field(struct tep_event_ormat *event, const char *name);
struct tep_format_field *tep_find_any_field(struct tep_event *event, const char *name); Functions resolver:
int tep_set_function_resolver(struct tep_handle *tep, tep_func_resolver_t *func, void *priv);
void tep_reset_function_resolver(struct tep_handle *tep);
const char *tep_find_function(struct tep_handle *tep, unsigned long long addr);
unsigned long long tep_find_function_address(struct tep_handle *tep, unsigned long long addr); Filter management:
struct tep_event_filter *tep_filter_alloc(struct tep_handle *tep);
enum tep_errno tep_filter_add_filter_str(struct tep_event_filter *filter, const char *filter_str);
enum tep_errno tep_filter_match(struct tep_event_filter *filter, struct tep_record *record);
int tep_filter_strerror(struct tep_event_filter *filter, enum tep_errno err, char *buf, size_t buflen);
int tep_event_filtered(struct tep_event_filter *filter, int event_id);
void tep_filter_reset(struct tep_event_filter *filter);
void tep_filter_free(struct tep_event_filter *filter);
char *tep_filter_make_string(struct tep_event_filter *filter, int event_id);
int tep_filter_remove_event(struct tep_event_filter *filter, int event_id);
int tep_filter_copy(struct tep_event_filter *dest, struct tep_event_filter *source);
int tep_filter_compare(struct tep_event_filter *filter1, struct tep_event_filter *filter2); Parsing various data from the records:
int tep_data_type(struct tep_handle *tep, struct tep_record *rec);
int tep_data_pid(struct tep_handle *tep, struct tep_record *rec);
int tep_data_preempt_count(struct tep_handle *tep, struct tep_record *rec);
int tep_data_flags(struct tep_handle *tep, struct tep_record *rec); Command and task related APIs:
const char *tep_data_comm_from_pid(struct tep_handle *tep, int pid);
struct cmdline *tep_data_pid_from_comm(struct tep_handle *tep, const char *comm, struct cmdline *next);
int tep_register_comm(struct tep_handle *tep, const char *comm, int pid);
int tep_override_comm(struct tep_handle *tep, const char *comm, int pid);
bool tep_is_pid_registered(struct tep_handle *tep, int pid);
int tep_cmdline_pid(struct tep_handle *tep, struct cmdline *cmdline); Endian related APIs:
int tep_is_bigendian(void);
unsigned long long tep_read_number(struct tep_handle *tep, const void *ptr, int size);
bool tep_is_file_bigendian(struct tep_handle *tep);
void tep_set_file_bigendian(struct tep_handle *tep, enum tep_endian endian);
bool tep_is_local_bigendian(struct tep_handle *tep);
void tep_set_local_bigendian(struct tep_handle *tep, enum tep_endian endian); Control library logs:
int tep_set_loglevel(enum tep_loglevel level); KVM plugin calllbacks: (Defined by the application and complied with -rdynamic)
const char *tep_plugin_kvm_get_func(struct tep_event *event,
struct tep_record *record,
unsigned long long *paddr);
void tep_plugin_kvm_put_func(const char *func); Trace sequences: #include <trace-seq.h>
void trace_seq_init(struct trace_seq *s);
void trace_seq_reset(struct trace_seq *s);
void trace_seq_destroy(struct trace_seq *s);
int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
int trace_seq_puts(struct trace_seq *s, const char *str);
int trace_seq_putc(struct trace_seq *s, unsigned char c);
void trace_seq_terminate(struct trace_seq *s);
int trace_seq_do_fprintf(struct trace_seq *s, FILE *fp);
int trace_seq_do_printf(struct trace_seq *s);

DESCRIPTION

The libtraceevent(3) library provides APIs to access kernel tracepoint events, located in the tracefs file system under the events directory.

ENVIRONMENT

TRACEEVENT_PLUGIN_DIR

Additional plugin directory. All shared object files, located in this directory will be loaded as traceevent plugins.

FILES

event-parse.h

Header file to include in order to have access to the library APIs. trace-seq.h
Header file to include in order to have access to trace sequences related APIs.
Trace sequences are used to allow a function to call several other functions
to create a string of data to use. -ltraceevent
Linker switch to add when building a program that uses the library.

SEE ALSO

trace-cmd(1)

AUTHOR

Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, author of this man page.

REPORTING BUGS

Report bugs to <linux-trace-devel@vger.kernel.org[3]>

LICENSE

libtraceevent is Free Software licensed under the GNU LGPL 2.1

RESOURCES

https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/

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
09/24/2022 libtraceevent 1.6.3