testcases/kernel/uevents/uevent02.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2019 Cyril Hrubis <chrubis@suse.cz>
 * Copyright (c) Linux Test Project, 2019-2023
 */

/*\
 * Very simple uevent netlink socket test.
 *
 * We fork a child that listens for a kernel events while parents creates and
 * removes a tun network device which should produce two several add and remove
 * events.
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/if_tun.h>

#include "tst_kconfig.h"
#include "tst_test.h"

#include "uevent.h"

#define TUN_PATH "/dev/net/tun"
#define MAX_ADD_UEVENTS 4
#define MAX_REM_UEVENTS 4

static struct uevent_desc add = {
	.msg = "add@/devices/virtual/net/ltp-tun0",
	.value_cnt = 4,
	.values = (const char*[]) {
		"ACTION=add",
		"DEVPATH=/devices/virtual/net/ltp-tun0",
		"SUBSYSTEM=net",
		"INTERFACE=ltp-tun0",
	}
};

static struct uevent_desc add_rx = {
	.msg = "add@/devices/virtual/net/ltp-tun0/queues/rx-0",
	.value_cnt = 3,
	.values = (const char*[]) {
		"ACTION=add",
		"DEVPATH=/devices/virtual/net/ltp-tun0/queues/rx-0",
		"SUBSYSTEM=queues",
	}
};

static struct uevent_desc add_tx = {
	.msg = "add@/devices/virtual/net/ltp-tun0/queues/tx-0",
	.value_cnt = 3,
	.values = (const char*[]) {
		"ACTION=add",
		"DEVPATH=/devices/virtual/net/ltp-tun0/queues/tx-0",
		"SUBSYSTEM=queues",
	}
};

static struct uevent_desc rem_rx = {
	.msg = "remove@/devices/virtual/net/ltp-tun0/queues/rx-0",
	.value_cnt = 3,
	.values = (const char*[]) {
		"ACTION=remove",
		"DEVPATH=/devices/virtual/net/ltp-tun0/queues/rx-0",
		"SUBSYSTEM=queues",
	}
};

static struct uevent_desc rem_tx = {
	.msg = "remove@/devices/virtual/net/ltp-tun0/queues/tx-0",
	.value_cnt = 3,
	.values = (const char*[]) {
		"ACTION=remove",
		"DEVPATH=/devices/virtual/net/ltp-tun0/queues/tx-0",
		"SUBSYSTEM=queues",
	}
};

static struct uevent_desc rem = {
	.msg = "remove@/devices/virtual/net/ltp-tun0",
	.value_cnt = 4,
	.values = (const char*[]) {
		"ACTION=remove",
		"DEVPATH=/devices/virtual/net/ltp-tun0",
		"SUBSYSTEM=net",
		"INTERFACE=ltp-tun0",
	}
};

static const struct uevent_desc *add_uevents[MAX_ADD_UEVENTS];
static const struct uevent_desc *rem_uevents[MAX_REM_UEVENTS];

static void generate_tun_uevents(void)
{
	int fd = SAFE_OPEN(TUN_PATH, O_RDWR);

	struct ifreq ifr = {
		.ifr_flags = IFF_TUN,
		.ifr_name = "ltp-tun0",
	};

	SAFE_IOCTL(fd, TUNSETIFF, (void *)&ifr);

	SAFE_IOCTL(fd, TUNSETPERSIST, 0);

	SAFE_CLOSE(fd);
}

static void verify_uevent(void)
{
	int pid, fd;

	pid = SAFE_FORK();
	if (!pid) {
		fd = open_uevent_netlink();
		TST_CHECKPOINT_WAKE(0);
		wait_for_uevents_unordered(fd, add_uevents);
		wait_for_uevents_unordered(fd, rem_uevents);
		close(fd);
		exit(0);
	}

	TST_CHECKPOINT_WAIT(0);

	generate_tun_uevents();

	wait_for_pid(pid);
}

static void setup(void)
{
	struct tst_kconfig_var kconfig = TST_KCONFIG_INIT("CONFIG_RPS");
	int i = 0, j = 0;

	tst_kconfig_read(&kconfig, 1);

	add_uevents[i++] = &add;
	if (kconfig.choice == 'y')
		add_uevents[i++] = &add_rx;
	add_uevents[i++] = &add_tx;
	add_uevents[i++] = NULL;

	if (kconfig.choice == 'y')
		rem_uevents[j++] = &rem_rx;
	rem_uevents[j++] = &rem_tx;
	rem_uevents[j++] = &rem;
	rem_uevents[j++] = NULL;
}

static struct tst_test test = {
	.setup = setup,
	.test_all = verify_uevent,
	.forks_child = 1,
	.needs_checkpoints = 1,
	.needs_kconfigs = (const char *const []) {
		"CONFIG_TUN",
		NULL
	},
	.needs_root = 1
};