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// SPDX-License-Identifier: GPL-2.0
/*
* trace helpers.
*
* Copyright (C) 2022 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
*/
#include <sys/sendfile.h>
#include <tracefs.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <rv.h>
#include <trace.h>
#include <utils.h>
/*
* create_instance - create a trace instance with *instance_name
*/
static struct tracefs_instance *create_instance(char *instance_name)
{
return tracefs_instance_create(instance_name);
}
/*
* destroy_instance - remove a trace instance and free the data
*/
static void destroy_instance(struct tracefs_instance *inst)
{
tracefs_instance_destroy(inst);
tracefs_instance_free(inst);
}
/**
* collect_registered_events - call the existing callback function for the event
*
* If an event has a registered callback function, call it.
* Otherwise, ignore the event.
*
* Returns 0 if the event was collected, 1 if the tool should stop collecting trace.
*/
int
collect_registered_events(struct tep_event *event, struct tep_record *record,
int cpu, void *context)
{
struct trace_instance *trace = context;
struct trace_seq *s = trace->seq;
if (should_stop())
return 1;
if (!event->handler)
return 0;
event->handler(s, record, event, context);
return 0;
}
/**
* trace_instance_destroy - destroy and free a rv trace instance
*/
void trace_instance_destroy(struct trace_instance *trace)
{
if (trace->inst) {
destroy_instance(trace->inst);
trace->inst = NULL;
}
if (trace->seq) {
free(trace->seq);
trace->seq = NULL;
}
if (trace->tep) {
tep_free(trace->tep);
trace->tep = NULL;
}
}
/**
* trace_instance_init - create a trace instance
*
* It is more than the tracefs instance, as it contains other
* things required for the tracing, such as the local events and
* a seq file.
*
* Note that the trace instance is returned disabled. This allows
* the tool to apply some other configs, like setting priority
* to the kernel threads, before starting generating trace entries.
*
* Returns 0 on success, non-zero otherwise.
*/
int trace_instance_init(struct trace_instance *trace, char *name)
{
trace->seq = calloc(1, sizeof(*trace->seq));
if (!trace->seq)
goto out_err;
trace_seq_init(trace->seq);
trace->inst = create_instance(name);
if (!trace->inst)
goto out_err;
trace->tep = tracefs_local_events(NULL);
if (!trace->tep)
goto out_err;
/*
* Let the main enable the record after setting some other
* things such as the priority of the tracer's threads.
*/
tracefs_trace_off(trace->inst);
return 0;
out_err:
trace_instance_destroy(trace);
return 1;
}
/**
* trace_instance_start - start tracing a given rv instance
*
* Returns 0 on success, -1 otherwise.
*/
int trace_instance_start(struct trace_instance *trace)
{
return tracefs_trace_on(trace->inst);
}
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