Eiichi Tsukata | 781e954 | 2013-04-11 20:25:15 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Ftrace trace backend |
| 3 | * |
| 4 | * Copyright (C) 2013 Hitachi, Ltd. |
| 5 | * Created by Eiichi Tsukata <eiichi.tsukata.xh@hitachi.com> |
| 6 | * |
| 7 | * This work is licensed under the terms of the GNU GPL, version 2. See |
| 8 | * the COPYING file in the top-level directory. |
| 9 | * |
| 10 | */ |
| 11 | |
| 12 | #include <stdio.h> |
| 13 | #include <string.h> |
| 14 | #include <fcntl.h> |
| 15 | #include <limits.h> |
| 16 | #include "trace.h" |
| 17 | #include "trace/control.h" |
| 18 | |
| 19 | int trace_marker_fd; |
| 20 | |
| 21 | static int find_debugfs(char *debugfs) |
| 22 | { |
| 23 | char type[100]; |
| 24 | FILE *fp; |
| 25 | |
| 26 | fp = fopen("/proc/mounts", "r"); |
| 27 | if (fp == NULL) { |
| 28 | return 0; |
| 29 | } |
| 30 | |
| 31 | while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n", |
| 32 | debugfs, type) == 2) { |
| 33 | if (strcmp(type, "debugfs") == 0) { |
| 34 | break; |
| 35 | } |
| 36 | } |
| 37 | fclose(fp); |
| 38 | |
| 39 | if (strcmp(type, "debugfs") != 0) { |
| 40 | return 0; |
| 41 | } |
| 42 | return 1; |
| 43 | } |
| 44 | |
| 45 | void trace_print_events(FILE *stream, fprintf_function stream_printf) |
| 46 | { |
| 47 | TraceEventID i; |
| 48 | |
| 49 | for (i = 0; i < trace_event_count(); i++) { |
| 50 | TraceEvent *ev = trace_event_id(i); |
| 51 | stream_printf(stream, "%s [Event ID %u] : state %u\n", |
| 52 | trace_event_get_name(ev), i, trace_event_get_state_dynamic(ev)); |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state) |
| 57 | { |
| 58 | ev->dstate = state; |
| 59 | } |
| 60 | |
| 61 | bool trace_backend_init(const char *events, const char *file) |
| 62 | { |
| 63 | char debugfs[PATH_MAX]; |
| 64 | char path[PATH_MAX]; |
| 65 | int debugfs_found; |
| 66 | int trace_fd = -1; |
| 67 | |
| 68 | if (file) { |
| 69 | fprintf(stderr, "error: -trace file=...: " |
| 70 | "option not supported by the selected tracing backend\n"); |
| 71 | return false; |
| 72 | } |
| 73 | |
| 74 | debugfs_found = find_debugfs(debugfs); |
| 75 | if (debugfs_found) { |
| 76 | snprintf(path, PATH_MAX, "%s/tracing/tracing_on", debugfs); |
| 77 | trace_fd = open(path, O_WRONLY); |
| 78 | if (trace_fd < 0) { |
| 79 | perror("Could not open ftrace 'tracing_on' file"); |
| 80 | return false; |
| 81 | } else { |
| 82 | if (write(trace_fd, "1", 1) < 0) { |
| 83 | perror("Could not write to 'tracing_on' file"); |
| 84 | close(trace_fd); |
| 85 | return false; |
| 86 | } |
| 87 | close(trace_fd); |
| 88 | } |
| 89 | snprintf(path, PATH_MAX, "%s/tracing/trace_marker", debugfs); |
| 90 | trace_marker_fd = open(path, O_WRONLY); |
| 91 | if (trace_marker_fd < 0) { |
| 92 | perror("Could not open ftrace 'trace_marker' file"); |
| 93 | return false; |
| 94 | } |
| 95 | } else { |
| 96 | fprintf(stderr, "debugfs is not mounted\n"); |
| 97 | return false; |
| 98 | } |
| 99 | |
| 100 | trace_backend_init_events(events); |
| 101 | return true; |
| 102 | } |