103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
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/*
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* Ftrace trace backend
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*
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* Copyright (C) 2013 Hitachi, Ltd.
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* Created by Eiichi Tsukata <eiichi.tsukata.xh@hitachi.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <limits.h>
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#include "trace.h"
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#include "trace/control.h"
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int trace_marker_fd;
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static int find_debugfs(char *debugfs)
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{
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char type[100];
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FILE *fp;
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fp = fopen("/proc/mounts", "r");
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if (fp == NULL) {
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return 0;
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}
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while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
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debugfs, type) == 2) {
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if (strcmp(type, "debugfs") == 0) {
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break;
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}
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}
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fclose(fp);
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if (strcmp(type, "debugfs") != 0) {
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return 0;
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}
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return 1;
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}
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void trace_print_events(FILE *stream, fprintf_function stream_printf)
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{
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TraceEventID i;
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for (i = 0; i < trace_event_count(); i++) {
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TraceEvent *ev = trace_event_id(i);
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stream_printf(stream, "%s [Event ID %u] : state %u\n",
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trace_event_get_name(ev), i, trace_event_get_state_dynamic(ev));
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}
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}
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void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
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{
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ev->dstate = state;
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}
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bool trace_backend_init(const char *events, const char *file)
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{
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char debugfs[PATH_MAX];
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char path[PATH_MAX];
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int debugfs_found;
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int trace_fd = -1;
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if (file) {
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fprintf(stderr, "error: -trace file=...: "
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"option not supported by the selected tracing backend\n");
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return false;
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}
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debugfs_found = find_debugfs(debugfs);
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if (debugfs_found) {
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snprintf(path, PATH_MAX, "%s/tracing/tracing_on", debugfs);
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trace_fd = open(path, O_WRONLY);
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if (trace_fd < 0) {
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perror("Could not open ftrace 'tracing_on' file");
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return false;
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} else {
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if (write(trace_fd, "1", 1) < 0) {
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perror("Could not write to 'tracing_on' file");
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close(trace_fd);
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return false;
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}
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close(trace_fd);
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}
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snprintf(path, PATH_MAX, "%s/tracing/trace_marker", debugfs);
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trace_marker_fd = open(path, O_WRONLY);
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if (trace_marker_fd < 0) {
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perror("Could not open ftrace 'trace_marker' file");
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return false;
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}
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} else {
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fprintf(stderr, "debugfs is not mounted\n");
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return false;
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}
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trace_backend_init_events(events);
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return true;
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}
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