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1// SPDX-License-Identifier: GPL-2.02/*3 * trace helpers.4 *5 * Copyright (C) 2022 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>6 */7 8#include <sys/sendfile.h>9#include <tracefs.h>10#include <signal.h>11#include <stdlib.h>12#include <unistd.h>13#include <errno.h>14 15#include <rv.h>16#include <trace.h>17#include <utils.h>18 19/*20 * create_instance - create a trace instance with *instance_name21 */22static struct tracefs_instance *create_instance(char *instance_name)23{24 return tracefs_instance_create(instance_name);25}26 27/*28 * destroy_instance - remove a trace instance and free the data29 */30static void destroy_instance(struct tracefs_instance *inst)31{32 tracefs_instance_destroy(inst);33 tracefs_instance_free(inst);34}35 36/**37 * collect_registered_events - call the existing callback function for the event38 *39 * If an event has a registered callback function, call it.40 * Otherwise, ignore the event.41 *42 * Returns 0 if the event was collected, 1 if the tool should stop collecting trace.43 */44int45collect_registered_events(struct tep_event *event, struct tep_record *record,46 int cpu, void *context)47{48 struct trace_instance *trace = context;49 struct trace_seq *s = trace->seq;50 51 if (should_stop())52 return 1;53 54 if (!event->handler)55 return 0;56 57 event->handler(s, record, event, context);58 59 return 0;60}61 62/**63 * trace_instance_destroy - destroy and free a rv trace instance64 */65void trace_instance_destroy(struct trace_instance *trace)66{67 if (trace->inst) {68 destroy_instance(trace->inst);69 trace->inst = NULL;70 }71 72 if (trace->seq) {73 free(trace->seq);74 trace->seq = NULL;75 }76 77 if (trace->tep) {78 tep_free(trace->tep);79 trace->tep = NULL;80 }81}82 83/**84 * trace_instance_init - create an trace instance85 *86 * It is more than the tracefs instance, as it contains other87 * things required for the tracing, such as the local events and88 * a seq file.89 *90 * Note that the trace instance is returned disabled. This allows91 * the tool to apply some other configs, like setting priority92 * to the kernel threads, before starting generating trace entries.93 *94 * Returns 0 on success, non-zero otherwise.95 */96int trace_instance_init(struct trace_instance *trace, char *name)97{98 trace->seq = calloc(1, sizeof(*trace->seq));99 if (!trace->seq)100 goto out_err;101 102 trace_seq_init(trace->seq);103 104 trace->inst = create_instance(name);105 if (!trace->inst)106 goto out_err;107 108 trace->tep = tracefs_local_events(NULL);109 if (!trace->tep)110 goto out_err;111 112 /*113 * Let the main enable the record after setting some other114 * things such as the priority of the tracer's threads.115 */116 tracefs_trace_off(trace->inst);117 118 return 0;119 120out_err:121 trace_instance_destroy(trace);122 return 1;123}124 125/**126 * trace_instance_start - start tracing a given rv instance127 *128 * Returns 0 on success, -1 otherwise.129 */130int trace_instance_start(struct trace_instance *trace)131{132 return tracefs_trace_on(trace->inst);133}134