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// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <sys/sendfile.h>
#include <tracefs.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include "trace.h"
#include "utils.h"
/*
* enable_tracer_by_name - enable a tracer on the given instance
*/
int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer_name)
{
enum tracefs_tracers tracer;
int retval;
tracer = TRACEFS_TRACER_CUSTOM;
debug_msg("enabling %s tracer\n", tracer_name);
retval = tracefs_tracer_set(inst, tracer, tracer_name);
if (retval < 0) {
if (errno == ENODEV)
err_msg("tracer %s not found!\n", tracer_name);
err_msg("failed to enable the tracer %s\n", tracer_name);
return -1;
}
return 0;
}
/*
* disable_tracer - set nop tracer to the insta
*/
void disable_tracer(struct tracefs_instance *inst)
{
enum tracefs_tracers t = TRACEFS_TRACER_NOP;
int retval;
retval = tracefs_tracer_set(inst, t);
if (retval < 0)
err_msg("oops, error disabling tracer\n");
}
/*
* create_instance - create a trace instance with *instance_name
*/
struct tracefs_instance *create_instance(char *instance_name)
{
return tracefs_instance_create(instance_name);
}
/*
* destroy_instance - remove a trace instance and free the data
*/
void destroy_instance(struct tracefs_instance *inst)
{
tracefs_instance_destroy(inst);
tracefs_instance_free(inst);
}
/*
* save_trace_to_file - save the trace output of the instance to the file
*/
int save_trace_to_file(struct tracefs_instance *inst, const char *filename)
{
const char *file = "trace";
mode_t mode = 0644;
char buffer[4096];
int out_fd, in_fd;
int retval = -1;
in_fd = tracefs_instance_file_open(inst, file, O_RDONLY);
if (in_fd < 0) {
err_msg("Failed to open trace file\n");
return -1;
}
out_fd = creat(filename, mode);
if (out_fd < 0) {
err_msg("Failed to create output file %s\n", filename);
goto out_close_in;
}
do {
retval = read(in_fd, buffer, sizeof(buffer));
if (retval <= 0)
goto out_close;
retval = write(out_fd, buffer, retval);
if (retval < 0)
goto out_close;
} while (retval > 0);
retval = 0;
out_close:
close(out_fd);
out_close_in:
close(in_fd);
return retval;
}
/*
* 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.
*/
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 (!event->handler)
return 0;
event->handler(s, record, event, context);
return 0;
}
/*
* trace_instance_destroy - destroy and free a rtla trace instance
*/
void trace_instance_destroy(struct trace_instance *trace)
{
if (trace->inst) {
disable_tracer(trace->inst);
destroy_instance(trace->inst);
}
if (trace->seq)
free(trace->seq);
if (trace->tep)
tep_free(trace->tep);
}
/*
* trace_instance_init - create an rtla 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.
*/
int trace_instance_init(struct trace_instance *trace, char *tool_name)
{
trace->seq = calloc(1, sizeof(*trace->seq));
if (!trace->seq)
goto out_err;
trace_seq_init(trace->seq);
trace->inst = create_instance(tool_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 rtla instance
*/
int trace_instance_start(struct trace_instance *trace)
{
return tracefs_trace_on(trace->inst);
}
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