bool kprobe_exists()

in helpers/trace_helpers.c [1071:1119]

• 43 lines of code
• 13 McCabe index (conditional complexity)

bool kprobe_exists(const char *name)
{
	char sym_name[256];
	FILE *f;
	int ret;

	f = fopen("/sys/kernel/debug/tracing/available_filter_functions", "r");
	if (!f)
		goto slow_path;

	while (true) {
		ret = fscanf(f, "%s%*[^\n]\n", sym_name);
		if (ret == EOF && feof(f))
			break;
		if (ret != 1) {
			fprintf(stderr, "failed to read symbol from available_filter_functions\n");
			break;
		}
		if (!strcmp(name, sym_name)) {
			fclose(f);
			return true;
		}
	}

	fclose(f);
	return false;

slow_path:
	f = fopen("/proc/kallsyms", "r");
	if (!f)
		return false;

	while (true) {
		ret = fscanf(f, "%*x %*c %s%*[^\n]\n", sym_name);
		if (ret == EOF && feof(f))
			break;
		if (ret != 1) {
			fprintf(stderr, "failed to read symbol from kallsyms\n");
			break;
		}
		if (!strcmp(name, sym_name)) {
			fclose(f);
			return true;
		}
	}

	fclose(f);
	return false;
}