bool ftrace_init(void) { char mount_point[PATH_MAX]; char path[PATH_MAX]; int debugfs_found; int trace_fd = -1; debugfs_found = find_mount(mount_point, "debugfs"); if (debugfs_found) { snprintf(path, PATH_MAX, "%s/tracing/tracing_on", mount_point); trace_fd = open(path, O_WRONLY); if (trace_fd < 0) { if (errno == EACCES) { trace_marker_fd = open("/dev/null", O_WRONLY); if (trace_marker_fd != -1) { return true; } } perror("Could not open ftrace 'tracing_on' file"); return false; } else { if (write(trace_fd, "1", 1) < 0) { perror("Could not write to 'tracing_on' file"); close(trace_fd); return false; } close(trace_fd); } snprintf(path, PATH_MAX, "%s/tracing/trace_marker", mount_point); trace_marker_fd = open(path, O_WRONLY); if (trace_marker_fd < 0) { perror("Could not open ftrace 'trace_marker' file"); return false; } } else { fprintf(stderr, "debugfs is not mounted\n"); return false; } return true; }