xref: /aosp_15_r20/external/ltp/testcases/kernel/syscalls/ioctl/ioctl07.c (revision 49cdfc7efb34551c7342be41a7384b9c40d7cab7)

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2017 Carlo Marcelo Arenas Belón <[email protected]>
 */

/*\
 * [Description]
 *
 * Very basic test for the RND* ioctls.
 *
 * Reads the entropy available from both /proc and the ioctl and compares
 * they are similar enough (within a configured fuzz factor).
 *
 */

#include <asm/types.h>
#include <linux/random.h>
#include <stdlib.h>
#include "tst_test.h"

static char *s_fuzz;
static int fuzz = 2;
static int fd;

static void verify_ioctl(void)
{
	int cnt, pcnt;

	SAFE_IOCTL(fd, RNDGETENTCNT, &cnt);
	SAFE_FILE_SCANF("/proc/sys/kernel/random/entropy_avail", "%d", &pcnt);
	tst_res(TINFO, "entropy value from ioctl: %d, proc: %d", cnt, pcnt);

	if (abs(pcnt - cnt) <= fuzz)
		tst_res(TPASS, "entropy value within expected parameters");
	else
		tst_res(TFAIL, "incorrect entropy value from ioctl");
}

static void setup(void)
{
	fd = SAFE_OPEN("/dev/urandom", O_RDONLY);
	if (s_fuzz)
		fuzz = SAFE_STRTOL(s_fuzz, 0, 4096);
}

static void cleanup(void)
{
	if (fd > 0)
		SAFE_CLOSE(fd);
}

static struct tst_test test = {
	.setup = setup,
	.cleanup = cleanup,
	.options = (struct tst_option[]) {
		{"f:", &s_fuzz, "Fuzz factor for valid match (default 2)"},
		{}
	},
	.test_all = verify_ioctl,
};