core: merge branch 'th/sysctl-ifname-race-bgo775613'

https://bugzilla.gnome.org/show_bug.cgi?id=775613

38 files changed, 1221 insertions, 534 deletions

diff --git a/shared/nm-utils/nm-macros-internal.h b/shared/nm-utils/nm-macros-internal.h
index fdb45f9291..24499172ca 100644
--- a/shared/nm-utils/nm-macros-internal.h
+++ b/shared/nm-utils/nm-macros-internal.h
@@ -22,7 +22,9 @@
 #ifndef __NM_MACROS_INTERNAL_H__
 #define __NM_MACROS_INTERNAL_H__
 
+#include <stdio.h>
 #include <stdlib.h>
+#include <errno.h>
 
 #include "nm-glib.h"
 
@@ -59,6 +61,37 @@ _nm_auto_free_gstring_impl (GString **str)
 }
 #define nm_auto_free_gstring nm_auto(_nm_auto_free_gstring_impl)
 
+static inline void
+_nm_auto_close_impl (int *pfd)
+{
+	if (*pfd >= 0) {
+		int errsv = errno;
+
+		(void) close (*pfd);
+		errno = errsv;
+	}
+}
+#define nm_auto_close nm_auto(_nm_auto_close_impl)
+
+static inline void
+_nm_auto_fclose_impl (FILE **pfd)
+{
+	if (*pfd) {
+		int errsv = errno;
+
+		(void) fclose (*pfd);
+		errno = errsv;
+	}
+}
+#define nm_auto_fclose nm_auto(_nm_auto_fclose_impl)
+
+static inline void
+_nm_auto_protect_errno (int *p_saved_errno)
+{
+	errno = *p_saved_errno;
+}
+#define NM_AUTO_PROTECT_ERRNO(errsv_saved) nm_auto(_nm_auto_protect_errno) _nm_unused const int errsv_saved = (errno)
+
 /*****************************************************************************/
 
 /* http://stackoverflow.com/a/11172679 */
diff --git a/src/devices/adsl/nm-atm-manager.c b/src/devices/adsl/nm-atm-manager.c
index 2ff2fc1840..b04e9fe717 100644
--- a/src/devices/adsl/nm-atm-manager.c
+++ b/src/devices/adsl/nm-atm-manager.c
@@ -137,7 +137,7 @@ adsl_add (NMAtmManager *self, GUdevDevice *udev_device)
 	atm_index_path = g_strdup_printf ("/sys/class/atm/%s/atmindex",
 	                                  NM_ASSERT_VALID_PATH_COMPONENT (ifname));
 	atm_index = (int) nm_platform_sysctl_get_int_checked (NM_PLATFORM_GET,
-	                                                      atm_index_path,
+	                                                      NMP_SYSCTL_PATHID_ABSOLUTE (atm_index_path),
 	                                                      10, 0, G_MAXINT,
 	                                                      -1);
 	if (atm_index < 0) {
diff --git a/src/devices/adsl/nm-device-adsl.c b/src/devices/adsl/nm-device-adsl.c
index 6cf808e687..9af6e69035 100644
--- a/src/devices/adsl/nm-device-adsl.c
+++ b/src/devices/adsl/nm-device-adsl.c
@@ -158,7 +158,7 @@ br2684_assign_vcc (NMDeviceAdsl *self, NMSettingAdsl *s_adsl)
 	g_return_val_if_fail (priv->brfd == -1, FALSE);
 	g_return_val_if_fail (priv->nas_ifname != NULL, FALSE);
 
-	priv->brfd = socket (PF_ATMPVC, SOCK_DGRAM, ATM_AAL5);
+	priv->brfd = socket (PF_ATMPVC, SOCK_DGRAM | SOCK_CLOEXEC, ATM_AAL5);
 	if (priv->brfd < 0) {
 		errsv = errno;
 		_LOGE (LOGD_ADSL, "failed to open ATM control socket (%d)", errsv);
@@ -344,7 +344,7 @@ br2684_create_iface (NMDeviceAdsl *self,
 		nm_clear_g_source (&priv->nas_update_id);
 	}
 
-	fd = socket (PF_ATMPVC, SOCK_DGRAM, ATM_AAL5);
+	fd = socket (PF_ATMPVC, SOCK_DGRAM | SOCK_CLOEXEC, ATM_AAL5);
 	if (fd < 0) {
 		errsv = errno;
 		_LOGE (LOGD_ADSL, "failed to open ATM control socket (%d)", errsv);
@@ -547,7 +547,7 @@ carrier_update_cb (gpointer user_data)
 
 	path  = g_strdup_printf ("/sys/class/atm/%s/carrier",
 	                         NM_ASSERT_VALID_PATH_COMPONENT (nm_device_get_iface (NM_DEVICE (self))));
-	carrier = (int) nm_platform_sysctl_get_int_checked (NM_PLATFORM_GET, path, 10, 0, 1, -1);
+	carrier = (int) nm_platform_sysctl_get_int_checked (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (path), 10, 0, 1, -1);
 	g_free (path);
 
 	if (carrier != -1)
diff --git a/src/devices/bluetooth/nm-bluez5-dun.c b/src/devices/bluetooth/nm-bluez5-dun.c
index 4c93feba60..aba3a0dd97 100644
--- a/src/devices/bluetooth/nm-bluez5-dun.c
+++ b/src/devices/bluetooth/nm-bluez5-dun.c
@@ -64,7 +64,7 @@ dun_connect (NMBluez5DunContext *context)
 		.channel = context->rfcomm_channel
 	};
 
-	context->rfcomm_fd = socket (AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
+	context->rfcomm_fd = socket (AF_BLUETOOTH, SOCK_STREAM | SOCK_CLOEXEC, BTPROTO_RFCOMM);
 	if (context->rfcomm_fd < 0) {
 		int errsv = errno;
 		error = g_error_new (NM_BT_ERROR, NM_BT_ERROR_DUN_CONNECT_FAILED,
@@ -112,7 +112,7 @@ dun_connect (NMBluez5DunContext *context)
 	context->rfcomm_id = devid;
 
 	snprintf (tty, ttylen, "/dev/rfcomm%d", devid);
-	while ((context->rfcomm_tty_fd = open (tty, O_RDONLY | O_NOCTTY)) < 0 && try--) {
+	while ((context->rfcomm_tty_fd = open (tty, O_RDONLY | O_NOCTTY | O_CLOEXEC)) < 0 && try--) {
 		if (try) {
 			g_usleep (100 * 1000);
 			continue;
diff --git a/src/devices/nm-device-ethernet.c b/src/devices/nm-device-ethernet.c
index 43084d49b9..2f9a092a0f 100644
--- a/src/devices/nm-device-ethernet.c
+++ b/src/devices/nm-device-ethernet.c
@@ -208,7 +208,7 @@ _update_s390_subchannels (NMDeviceEthernet *self)
 			gs_free char *path = NULL, *value = NULL;
 
 			path = g_strdup_printf ("%s/%s", parent_path, item);
-			value = nm_platform_sysctl_get (NM_PLATFORM_GET, path);
+			value = nm_platform_sysctl_get (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (path));
 
 			if (   !strcmp (item, "portname")
 			    && !g_strcmp0 (value, "no portname required")) {
@@ -827,7 +827,7 @@ link_negotiation_set (NMDevice *device)
 		}
 	}
 
-	if (!nm_platform_ethtool_get_link_settings (NM_PLATFORM_GET, nm_device_get_iface (device),
+	if (!nm_platform_ethtool_get_link_settings (NM_PLATFORM_GET, nm_device_get_ifindex (device),
 	                                            &link_autoneg, &link_speed, &link_duplex)) {
 		_LOGW (LOGD_DEVICE, "set-link: unable to retrieve link negotiation");
 		return;
@@ -852,7 +852,7 @@ link_negotiation_set (NMDevice *device)
 	}
 
 	if (!nm_platform_ethtool_set_link_settings (NM_PLATFORM_GET,
-	                                            nm_device_get_iface (device),
+	                                            nm_device_get_ifindex (device),
 	                                            autoneg,
 	                                            speed,
 	                                            duplex)) {
@@ -1243,7 +1243,7 @@ wake_on_lan_enable (NMDevice *device)
 	}
 	wol = NM_SETTING_WIRED_WAKE_ON_LAN_IGNORE;
 found:
-	return nm_platform_ethtool_set_wake_on_lan (NM_PLATFORM_GET, nm_device_get_iface (device), wol, password);
+	return nm_platform_ethtool_set_wake_on_lan (NM_PLATFORM_GET, nm_device_get_ifindex (device), wol, password);
 }
 
 /*****************************************************************************/
@@ -1609,7 +1609,7 @@ get_link_speed (NMDevice *device)
 	NMDeviceEthernetPrivate *priv = NM_DEVICE_ETHERNET_GET_PRIVATE (self);
 	guint32 speed;
 
-	if (!nm_platform_ethtool_get_link_settings (NM_PLATFORM_GET, nm_device_get_iface (device), NULL, &speed, NULL))
+	if (!nm_platform_ethtool_get_link_settings (NM_PLATFORM_GET, nm_device_get_ifindex (device), NULL, &speed, NULL))
 		return;
 	if (priv->speed == speed)
 		return;
diff --git a/src/devices/nm-device-infiniband.c b/src/devices/nm-device-infiniband.c
index 47c2a01656..b0871b0a95 100644
--- a/src/devices/nm-device-infiniband.c
+++ b/src/devices/nm-device-infiniband.c
@@ -77,10 +77,11 @@ get_generic_capabilities (NMDevice *device)
 static NMActStageReturn
 act_stage1_prepare (NMDevice *dev, NMDeviceStateReason *reason)
 {
+	nm_auto_close int dirfd = -1;
 	NMActStageReturn ret;
 	NMSettingInfiniband *s_infiniband;
+	char ifname_verified[IFNAMSIZ];
 	const char *transport_mode;
-	char *mode_path;
 	gboolean ok, no_firmware = FALSE;
 
 	g_return_val_if_fail (reason != NULL, NM_ACT_STAGE_RETURN_FAILURE);
@@ -94,11 +95,8 @@ act_stage1_prepare (NMDevice *dev, NMDeviceStateReason *reason)
 
 	transport_mode = nm_setting_infiniband_get_transport_mode (s_infiniband);
 
-	mode_path = g_strdup_printf ("/sys/class/net/%s/mode",
-	                             NM_ASSERT_VALID_PATH_COMPONENT (nm_device_get_iface (dev)));
-	if (!g_file_test (mode_path, G_FILE_TEST_EXISTS)) {
-		g_free (mode_path);
-
+	dirfd = nm_platform_sysctl_open_netdir (NM_PLATFORM_GET, nm_device_get_ifindex (dev), ifname_verified);
+	if (dirfd < 0) {
 		if (!strcmp (transport_mode, "datagram"))
 			return NM_ACT_STAGE_RETURN_SUCCESS;
 		else {
@@ -109,8 +107,7 @@ act_stage1_prepare (NMDevice *dev, NMDeviceStateReason *reason)
 
 	/* With some drivers the interface must be down to set transport mode */
 	nm_device_take_down (dev, TRUE);
-	ok = nm_platform_sysctl_set (NM_PLATFORM_GET, mode_path, transport_mode);
-	g_free (mode_path);
+	ok = nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_verified, "mode"), transport_mode);
 	nm_device_bring_up (dev, TRUE, &no_firmware);
 
 	if (!ok) {
diff --git a/src/devices/nm-device-tun.c b/src/devices/nm-device-tun.c
index 15bcacb0bc..ea70f1a539 100644
--- a/src/devices/nm-device-tun.c
+++ b/src/devices/nm-device-tun.c
@@ -80,7 +80,7 @@ reload_tun_properties (NMDeviceTun *self)
 
 	ifindex = nm_device_get_ifindex (NM_DEVICE (self));
 	if (ifindex > 0) {
-		if (!nm_platform_link_tun_get_properties (NM_PLATFORM_GET, ifindex, &props)) {
+		if (!nm_platform_link_tun_get_properties (NM_PLATFORM_GET, ifindex, NULL, &props)) {
 			_LOGD (LOGD_DEVICE, "tun-properties: cannot loading tun properties from platform for ifindex %d", ifindex);
 			ifindex = 0;
 		} else if (g_strcmp0 (priv->mode, props.mode) != 0) {
@@ -181,7 +181,7 @@ update_connection (NMDevice *device, NMConnection *connection)
 		nm_connection_add_setting (connection, (NMSetting *) s_tun);
 	}
 
-	if (!nm_platform_link_tun_get_properties (NM_PLATFORM_GET, nm_device_get_ifindex (device), &props)) {
+	if (!nm_platform_link_tun_get_properties (NM_PLATFORM_GET, nm_device_get_ifindex (device), NULL, &props)) {
 		_LOGW (LOGD_PLATFORM, "failed to get TUN interface info while updating connection.");
 		return;
 	}
diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 2785a1a890..af201d8ce9 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -629,13 +629,13 @@ init_ip6_config_dns_priority (NMDevice *self, NMIP6Config *config)
 gboolean
 nm_device_ipv6_sysctl_set (NMDevice *self, const char *property, const char *value)
 {
-	return nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip6_property_path (nm_device_get_ip_iface (self), property), value);
+	return nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (nm_device_get_ip_iface (self), property)), value);
 }
 
 static guint32
 nm_device_ipv6_sysctl_get_int32 (NMDevice *self, const char *property, gint32 fallback)
 {
-	return nm_platform_sysctl_get_int32 (NM_PLATFORM_GET, nm_utils_ip6_property_path (nm_device_get_ip_iface (self), property), fallback);
+	return nm_platform_sysctl_get_int32 (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (nm_device_get_ip_iface (self), property)), fallback);
 }
 
 gboolean
@@ -6771,7 +6771,7 @@ save_ip6_properties (NMDevice *self)
 	g_hash_table_remove_all (priv->ip6_saved_properties);
 
 	for (i = 0; i < G_N_ELEMENTS (ip6_properties_to_save); i++) {
-		value = nm_platform_sysctl_get (NM_PLATFORM_GET, nm_utils_ip6_property_path (ifname, ip6_properties_to_save[i]));
+		value = nm_platform_sysctl_get (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (ifname, ip6_properties_to_save[i])));
 		if (value) {
 			g_hash_table_insert (priv->ip6_saved_properties,
 			                     (char *) ip6_properties_to_save[i],
@@ -6832,7 +6832,7 @@ set_nm_ipv6ll (NMDevice *self, gboolean enable)
 		if (enable) {
 			/* Bounce IPv6 to ensure the kernel stops IPv6LL address generation */
 			value = nm_platform_sysctl_get (NM_PLATFORM_GET,
-			                                nm_utils_ip6_property_path (nm_device_get_ip_iface (self), "disable_ipv6"));
+			                                NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (nm_device_get_ip_iface (self), "disable_ipv6")));
 			if (g_strcmp0 (value, "0") == 0)
 				nm_device_ipv6_sysctl_set (self, "disable_ipv6", "1");
 			g_free (value);
@@ -6898,7 +6898,7 @@ _ip6_privacy_get (NMDevice *self)
 	 * Instead of reading static config files in /etc, just read the current sysctl value.
 	 * This works as NM only writes to "/proc/sys/net/ipv6/conf/IFNAME/use_tempaddr", but leaves
 	 * the "default" entry untouched. */
-	ip6_privacy = nm_platform_sysctl_get_int32 (NM_PLATFORM_GET, "/proc/sys/net/ipv6/conf/default/use_tempaddr", NM_SETTING_IP6_CONFIG_PRIVACY_UNKNOWN);
+	ip6_privacy = nm_platform_sysctl_get_int32 (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE ("/proc/sys/net/ipv6/conf/default/use_tempaddr"), NM_SETTING_IP6_CONFIG_PRIVACY_UNKNOWN);
 	return _ip6_privacy_clamp (ip6_privacy);
 }
 
@@ -7406,14 +7406,14 @@ share_init (void)
 	char **iter;
 	int errsv;
 
-	if (!nm_platform_sysctl_set (NM_PLATFORM_GET, "/proc/sys/net/ipv4/ip_forward", "1")) {
+	if (!nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE ("/proc/sys/net/ipv4/ip_forward"), "1")) {
 		errsv = errno;
 		nm_log_err (LOGD_SHARING, "share: error enabling IPv4 forwarding: (%d) %s",
 		            errsv, strerror (errsv));
 		return FALSE;
 	}
 
-	if (!nm_platform_sysctl_set (NM_PLATFORM_GET, "/proc/sys/net/ipv4/ip_dynaddr", "1")) {
+	if (!nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE ("/proc/sys/net/ipv4/ip_dynaddr"), "1")) {
 		errsv = errno;
 		nm_log_err (LOGD_SHARING, "share: error enabling dynamic addresses: (%d) %s",
 		            errsv, strerror (errsv));
@@ -7754,7 +7754,7 @@ activate_stage5_ip6_config_commit (NMDevice *self)
 		method = nm_utils_get_ip_config_method (connection, NM_TYPE_SETTING_IP6_CONFIG);
 
 		if (strcmp (method, NM_SETTING_IP6_CONFIG_METHOD_SHARED) == 0) {
-			if (!nm_platform_sysctl_set (NM_PLATFORM_GET, "/proc/sys/net/ipv6/conf/all/forwarding", "1")) {
+			if (!nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE ("/proc/sys/net/ipv6/conf/all/forwarding"), "1")) {
 				errsv = errno;
 				_LOGE (LOGD_SHARING, "share: error enabling IPv6 forwarding: (%d) %s", errsv, strerror (errsv));
 				nm_device_ip_method_failed (self, AF_INET6, NM_DEVICE_STATE_REASON_SHARED_START_FAILED);
diff --git a/src/devices/tests/test-lldp.c b/src/devices/tests/test-lldp.c
index 5d28d461df..4d25f9a681 100644
--- a/src/devices/tests/test-lldp.c
+++ b/src/devices/tests/test-lldp.c
@@ -350,7 +350,7 @@ _test_recv_fixture_setup (TestRecvFixture *fixture, gconstpointer user_data)
 	struct ifreq ifr = { };
 	int fd, s;
 
-	fd = open ("/dev/net/tun", O_RDWR);
+	fd = open ("/dev/net/tun", O_RDWR | O_CLOEXEC);
 	g_assert (fd >= 0);
 
 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
@@ -358,7 +358,7 @@ _test_recv_fixture_setup (TestRecvFixture *fixture, gconstpointer user_data)
 	g_assert (ioctl (fd, TUNSETIFF, &ifr) >= 0);
 
 	/* Bring the interface up */
-	s = socket (AF_INET, SOCK_DGRAM, 0);
+	s = socket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	g_assert (s >= 0);
 	ifr.ifr_flags |= IFF_UP;
 	g_assert (ioctl (s, SIOCSIFFLAGS, &ifr) >= 0);
diff --git a/src/devices/wwan/nm-modem.c b/src/devices/wwan/nm-modem.c
index df71017745..635f20ea74 100644
--- a/src/devices/wwan/nm-modem.c
+++ b/src/devices/wwan/nm-modem.c
@@ -497,18 +497,18 @@ ppp_stats (NMPPPManager *ppp_manager,
 static gboolean
 port_speed_is_zero (const char *port)
 {
-    struct termios options;
-    gs_fd_close int fd = -1;
+	struct termios options;
+	nm_auto_close int fd = -1;
 
-    fd = open (port, O_RDWR | O_NONBLOCK | O_NOCTTY);
-    if (fd < 0)
+	fd = open (port, O_RDWR | O_NONBLOCK | O_NOCTTY | O_CLOEXEC);
+	if (fd < 0)
 		return FALSE;
 
-    memset (&options, 0, sizeof (struct termios));
-    if (tcgetattr (fd, &options) != 0)
-        return FALSE;
+	memset (&options, 0, sizeof (struct termios));
+	if (tcgetattr (fd, &options) != 0)
+		return FALSE;
 
-    return cfgetospeed (&options) == B0;
+	return cfgetospeed (&options) == B0;
 }
 
 static NMActStageReturn
diff --git a/src/dns/nm-dns-manager.c b/src/dns/nm-dns-manager.c
index c8ebe23a4c..c52777cff7 100644
--- a/src/dns/nm-dns-manager.c
+++ b/src/dns/nm-dns-manager.c
@@ -719,7 +719,7 @@ update_resolv_conf (NMDnsManager *self,
 		}
 	}
 
-	if ((f = fopen (MY_RESOLV_CONF_TMP, "w")) == NULL) {
+	if ((f = fopen (MY_RESOLV_CONF_TMP, "we")) == NULL) {
 		errsv = errno;
 		g_set_error (error,
 		             NM_MANAGER_ERROR,
@@ -1594,7 +1594,7 @@ _check_resconf_immutable (NMDnsManagerResolvConfManager rc_manager)
 			}
 		}
 
-		fd = open (_PATH_RESCONF, O_RDONLY);
+		fd = open (_PATH_RESCONF, O_RDONLY | O_CLOEXEC);
 		if (fd != -1) {
 			if (ioctl (fd, FS_IOC_GETFLAGS, &flags) != -1)
 				immutable = NM_FLAGS_HAS (flags, FS_IMMUTABLE_FL);
diff --git a/src/main-utils.c b/src/main-utils.c
index bad3141abf..9e3aa7bd55 100644
--- a/src/main-utils.c
+++ b/src/main-utils.c
@@ -95,7 +95,7 @@ nm_main_utils_write_pidfile (const char *pidfile)
 	int fd;
 	gboolean success = FALSE;
 
-	if ((fd = open (pidfile, O_CREAT|O_WRONLY|O_TRUNC, 00644)) < 0) {
+	if ((fd = open (pidfile, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 00644)) < 0) {
 		fprintf (stderr, _("Opening %s failed: %s\n"), pidfile, strerror (errno));
 		return FALSE;
 	}
diff --git a/src/ndisc/nm-lndp-ndisc.c b/src/ndisc/nm-lndp-ndisc.c
index 6378c90039..9e5cdaa059 100644
--- a/src/ndisc/nm-lndp-ndisc.c
+++ b/src/ndisc/nm-lndp-ndisc.c
@@ -521,7 +521,7 @@ static inline int
 ipv6_sysctl_get (NMPlatform *platform, const char *ifname, const char *property, int min, int max, int defval)
 {
 	return (int) nm_platform_sysctl_get_int_checked (platform,
-	                                                 nm_utils_ip6_property_path (ifname, property),
+	                                                 NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (ifname, property)),
 	                                                 10,
 	                                                 min,
 	                                                 max,
diff --git a/src/nm-core-utils.c b/src/nm-core-utils.c
index a0067aafc1..70af933835 100644
--- a/src/nm-core-utils.c
+++ b/src/nm-core-utils.c
@@ -2802,6 +2802,246 @@ nm_utils_fd_read_loop_exact (int fd, void *buf, size_t nbytes, bool do_poll)
 	return 0;
 }
 
+_nm_printf (3, 4)
+static int
+_get_contents_error (GError **error, int errsv, const char *format, ...)
+{
+	if (errsv < 0)
+		errsv = -errsv;
+	else if (!errsv)
+		errsv = errno;
+
+	if (error) {
+		char *msg;
+		va_list args;
+
+		va_start (args, format);
+		msg = g_strdup_vprintf (format, args);
+		va_end (args);
+		g_set_error (error,
+		             G_FILE_ERROR,
+		             g_file_error_from_errno (errsv),
+		             "%s: %s",
+		             msg, g_strerror (errsv));
+		g_free (msg);
+	}
+	return -errsv;
+}
+
+/**
+ * nm_utils_fd_get_contents:
+ * @fd: open file descriptor to read. The fd will not be closed,
+ *   but don't rely on it's state afterwards.
+ * @max_length: allocate at most @max_length bytes. If the
+ *   file is larger, reading will fail. Set to zero to use
+ *   a very large default.
+ *
+ *   WARNING: @max_length is here to avoid a crash for huge/unlimited files.
+ *   For example, stat(/sys/class/net/enp0s25/ifindex) gives a filesize of
+ *   4K, although the actual real is small. @max_length is the memory
+ *   allocated in the process of reading the file, thus it must be at least
+ *   the size reported by fstat.
+ *   If you set it to 1K, read will fail because fstat() claims the
+ *   file is larger.
+ *
+ * @contents: the output buffer with the file read. It is always
+ *   NUL terminated. The buffer is at most @max_length long, including
+ *  the NUL byte. That is, it reads only files up to a length of
+ *  @max_length - 1 bytes.
+ * @length: optional output argument of the read file size.
+ *
+ * A reimplementation of g_file_get_contents() with a few differences:
+ *   - accepts an open fd, instead of a path name. This allows you to
+ *     use openat().
+ *   - limits the maxium filesize to max_length.
+ *
+ * Returns: a negative error code on failure.
+ */
+int
+nm_utils_fd_get_contents (int fd,
+                          gsize max_length,
+                          char **contents,
+                          gsize *length,
+                          GError **error)
+{
+	struct stat stat_buf;
+	gs_free char *str = NULL;
+
+	g_return_val_if_fail (fd >= 0, -EINVAL);
+	g_return_val_if_fail (contents, -EINVAL);
+	g_return_val_if_fail (!error || !*error, -EINVAL);
+
+	if (fstat (fd, &stat_buf) < 0)
+		return _get_contents_error (error, 0, "failure during fstat");
+
+	if (!max_length) {
+		/* default to a very large size, but not extreme */
+		max_length = 2 * 1024 * 1024;
+	}
+
+	if (   stat_buf.st_size > 0
+	    && S_ISREG (stat_buf.st_mode)) {
+		const gsize n_stat = stat_buf.st_size;
+		ssize_t n_read;
+
+		if (n_stat > max_length - 1)
+			return _get_contents_error (error, EMSGSIZE, "file too large (%zu+1 bytes with maximum %zu bytes)", n_stat, max_length);
+
+		str = g_try_malloc (n_stat + 1);
+		if (!str)
+			return _get_contents_error (error, ENOMEM, "failure to allocate buffer of %zu+1 bytes", n_stat);
+
+		n_read = nm_utils_fd_read_loop (fd, str, n_stat, TRUE);
+		if (n_read < 0)
+			return _get_contents_error (error, n_read, "error reading %zu bytes from file descriptor", n_stat);
+		str[n_read] = '\0';
+
+		if (n_read < n_stat) {
+			char *tmp;
+
+			tmp = g_try_realloc (str, n_read + 1);
+			if (!tmp)
+				return _get_contents_error (error, ENOMEM, "failure to reallocate buffer with %zu bytes", n_read + 1);
+			str = tmp;
+		}
+		NM_SET_OUT (length, n_read);
+	} else {
+		nm_auto_fclose FILE *f = NULL;
+		char buf[4096];
+		gsize n_have, n_alloc;
+
+		if (!(f = fdopen (fd, "r")))
+			return _get_contents_error (error, 0, "failure during fdopen");
+
+		n_have = 0;
+		n_alloc = 0;
+
+		while (!feof (f)) {
+			int errsv;
+			gsize n_read;
+
+			n_read = fread (buf, 1, sizeof (buf), f);
+			errsv = errno;
+			if (ferror (f))
+				return _get_contents_error (error, errsv, "error during fread");
+
+			if (   n_have > G_MAXSIZE - 1 - n_read
+			    || n_have + n_read + 1 > max_length) {
+				return _get_contents_error (error, EMSGSIZE, "file stream too large (%zu+1 bytes with maximum %zu bytes)",
+				                            (n_have > G_MAXSIZE - 1 - n_read) ? G_MAXSIZE : n_have + n_read,
+				                            max_length);
+			}
+
+			if (n_have + n_read + 1 >= n_alloc) {
+				char *tmp;
+
+				if (str) {
+					if (n_alloc >= max_length / 2)
+						n_alloc = max_length;
+					else
+						n_alloc *= 2;
+				} else
+					n_alloc = NM_MIN (n_read + 1, sizeof (buf));
+
+				tmp = g_try_realloc (str, n_alloc);
+				if (!tmp)
+					return _get_contents_error (error, ENOMEM, "failure to allocate buffer of %zu bytes", n_alloc);
+				str = tmp;
+			}
+
+			memcpy (str + n_have, buf, n_read);
+			n_have += n_read;
+		}
+
+		if (n_alloc == 0)
+			str = g_new0 (gchar, 1);
+		else {
+			str[n_have] = '\0';
+			if (n_have + 1 < n_alloc) {
+				char *tmp;
+
+				tmp = g_try_realloc (str, n_have + 1);
+				if (!tmp)
+					return _get_contents_error (error, ENOMEM, "failure to truncate buffer to %zu bytes", n_have + 1);
+				str = tmp;
+			}
+		}
+
+		NM_SET_OUT (length, n_have);
+	}
+
+	*contents = g_steal_pointer (&str);
+	return 0;
+}
+
+/**
+ * nm_utils_file_get_contents:
+ * @dirfd: optional file descriptor to use openat(). If negative, use plain open().
+ * @filename: the filename to open. Possibly relative to @dirfd.
+ * @max_length: allocate at most @max_length bytes.
+ *   WARNING: see nm_utils_fd_get_contents() hint about @max_length.
+ * @contents: the output buffer with the file read. It is always
+ *   NUL terminated. The buffer is at most @max_length long, including
+ *  the NUL byte. That is, it reads only files up to a length of
+ *  @max_length - 1 bytes.
+ * @length: optional output argument of the read file size.
+ *
+ * A reimplementation of g_file_get_contents() with a few differences:
+ *   - accepts an @dirfd to open @filename relative to that path via openat().
+ *   - limits the maxium filesize to max_length.
+ *   - uses O_CLOEXEC on internal file descriptor
+ *
+ * Returns: a negative error code on failure.
+ */
+int
+nm_utils_file_get_contents (int dirfd,
+                            const char *filename,
+                            gsize max_length,
+                            char **contents,
+                            gsize *length,
+                            GError **error)
+{
+	nm_auto_close int fd = -1;
+	int errsv;
+
+	g_return_val_if_fail (filename && filename[0], -EINVAL);
+
+	if (dirfd >= 0) {
+		fd = openat (dirfd, filename, O_RDONLY | O_CLOEXEC);
+		if (fd < 0) {
+			errsv = errno;
+
+			g_set_error (error,
+			             G_FILE_ERROR,
+			             g_file_error_from_errno (errsv),
+			             "Failed to open file \"%s\" with openat: %s",
+			             filename,
+			             g_strerror (errsv));
+			return -errsv;
+		}
+	} else {
+		fd = open (filename, O_RDONLY | O_CLOEXEC);
+		if (fd < 0) {
+			errsv = errno;
+
+			g_set_error (error,
+			             G_FILE_ERROR,
+			             g_file_error_from_errno (errsv),
+			             "Failed to open file \"%s\": %s",
+			             filename,
+			             g_strerror (errsv));
+			return -errsv;
+		}
+	}
+	return nm_utils_fd_get_contents (fd,
+	                                 max_length,
+	                                 contents,
+	                                 length,
+	                                 error);
+}
+
+/*****************************************************************************/
+
 /* taken from systemd's dev_urandom(). */
 int
 nm_utils_read_urandom (void *p, size_t nbytes)
@@ -2810,7 +3050,7 @@ nm_utils_read_urandom (void *p, size_t nbytes)
 	int r;
 
 again:
-	fd = open ("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+	fd = open ("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOCTTY);
 	if (fd < 0) {
 		r = errno;
 		if (r == EINTR)
diff --git a/src/nm-core-utils.h b/src/nm-core-utils.h
index 9cf196f709..f9d30b5ce4 100644
--- a/src/nm-core-utils.h
+++ b/src/nm-core-utils.h
@@ -313,6 +313,25 @@ int nm_utils_fd_wait_for_event (int fd, int event, gint64 timeout_ns);
 ssize_t nm_utils_fd_read_loop (int fd, void *buf, size_t nbytes, bool do_poll);
 int nm_utils_fd_read_loop_exact (int fd, void *buf, size_t nbytes, bool do_poll);
 
+int nm_utils_fd_get_contents (int fd,
+                              gsize max_length,
+                              char **contents,
+                              gsize *length,
+                              GError **error);
+
+int nm_utils_file_get_contents (int dirfd,
+                                const char *filename,
+                                gsize max_length,
+                                char **contents,
+                                gsize *length,
+                                GError **error);
+
+gboolean nm_utils_file_set_contents (const gchar *filename,
+                                     const gchar *contents,
+                                     gssize length,
+                                     mode_t mode,
+                                     GError **error);
+
 int nm_utils_read_urandom (void *p, size_t n);
 
 char *nm_utils_machine_id_read (void);
@@ -445,12 +464,6 @@ const char *nm_utils_dnsmasq_status_to_string (int status, char *dest, gsize siz
 void nm_utils_get_reverse_dns_domains_ip4 (guint32 ip, guint8 plen, GPtrArray *domains);
 void nm_utils_get_reverse_dns_domains_ip6 (const struct in6_addr *ip, guint8 plen, GPtrArray *domains);
 
-gboolean nm_utils_file_set_contents (const gchar *filename,
-                                     const gchar *contents,
-                                     gssize length,
-                                     mode_t mode,
-                                     GError **error);
-
 struct stat;
 
 gboolean nm_utils_validate_plugin (const char *path, struct stat *stat, GError **error);
diff --git a/src/nm-iface-helper.c b/src/nm-iface-helper.c
index aa14b085fe..393e8acc57 100644
--- a/src/nm-iface-helper.c
+++ b/src/nm-iface-helper.c
@@ -246,7 +246,7 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 		char val[16];
 
 		g_snprintf (val, sizeof (val), "%d", rdata->mtu);
-		nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip6_property_path (global_opt.ifname, "mtu"), val);
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "mtu")), val);
 	}
 
 	nm_ip6_config_merge (existing, ndisc_config, NM_IP_CONFIG_MERGE_DEFAULT);
@@ -465,7 +465,7 @@ main (int argc, char *argv[])
 	}
 
 	if (global_opt.dhcp4_address) {
-		nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip4_property_path (global_opt.ifname, "promote_secondaries"), "1");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip4_property_path (global_opt.ifname, "promote_secondaries")), "1");
 
 		dhcp4_client = nm_dhcp_manager_start_ip4 (nm_dhcp_manager_get (),
 		                                          global_opt.ifname,
@@ -512,10 +512,10 @@ main (int argc, char *argv[])
 		if (iid)
 			nm_ndisc_set_iid (ndisc, *iid);
 
-		nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip6_property_path (global_opt.ifname, "accept_ra"), "1");
-		nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_defrtr"), "0");
-		nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_pinfo"), "0");
-		nm_platform_sysctl_set (NM_PLATFORM_GET, nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_rtr_pref"), "0");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra")), "1");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_defrtr")), "0");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_pinfo")), "0");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_rtr_pref")), "0");
 
 		g_signal_connect (NM_PLATFORM_GET,
 		                  NM_PLATFORM_SIGNAL_IP6_ADDRESS_CHANGED,
diff --git a/src/nm-logging.c b/src/nm-logging.c
index 50927f8caf..c242d90319 100644
--- a/src/nm-logging.c
+++ b/src/nm-logging.c
@@ -599,6 +599,7 @@ _nm_log_impl (const char *file,
 	va_list args;
 	char *msg;
 	GTimeVal tv;
+	int errno_saved;
 
 	if ((guint) level >= G_N_ELEMENTS (_nm_logging_enabled_state))
 		g_return_if_reached ();
@@ -606,6 +607,8 @@ _nm_log_impl (const char *file,
 	if (!(_nm_logging_enabled_state[level] & domain))
 		return;
 
+	errno_saved = errno;
+
 	/* Make sure that %m maps to the specified error */
 	if (error != 0) {
 		if (error < 0)
@@ -719,6 +722,8 @@ _nm_log_impl (const char *file,
 	}
 
 	g_free (msg);
+
+	errno = errno_saved;
 }
 
 /*****************************************************************************/
diff --git a/src/nm-manager.c b/src/nm-manager.c
index 8414f18802..58a60b197f 100644
--- a/src/nm-manager.c
+++ b/src/nm-manager.c
@@ -5450,7 +5450,7 @@ rfkill_change (NMManager *self, const char *desc, RfKillType rtype, gboolean ena
 	g_return_if_fail (rtype == RFKILL_TYPE_WLAN || rtype == RFKILL_TYPE_WWAN);
 
 	errno = 0;
-	fd = open ("/dev/rfkill", O_RDWR);
+	fd = open ("/dev/rfkill", O_RDWR | O_CLOEXEC);
 	if (fd < 0) {
 		if (errno == EACCES)
 			_LOGW (LOGD_RFKILL, "(%s): failed to open killswitch device", desc);
diff --git a/src/platform/nm-fake-platform.c b/src/platform/nm-fake-platform.c
index 0f34b8453f..b92f56ce21 100644
--- a/src/platform/nm-fake-platform.c
+++ b/src/platform/nm-fake-platform.c
@@ -118,21 +118,43 @@ _ip4_address_equal_peer_net (in_addr_t peer1, in_addr_t peer2, guint8 plen)
 
 /*****************************************************************************/
 
+#define ASSERT_SYSCTL_ARGS(pathid, dirfd, path) \
+	G_STMT_START { \
+		const char *const _pathid = (pathid); \
+		const int _dirfd = (dirfd); \
+		const char *const _path = (path); \
+		\
+		g_assert (_path && _path[0]); \
+		g_assert (!strstr (_path, "/../")); \
+		if (_dirfd < 0) { \
+			g_assert (!_pathid); \
+			g_assert (_path[0] == '/'); \
+			g_assert (   g_str_has_prefix (_path, "/proc/sys/") \
+			          || g_str_has_prefix (_path, "/sys/")); \
+		} else { \
+			g_assert_not_reached (); \
+		} \
+	} G_STMT_END
+
 static gboolean
-sysctl_set (NMPlatform *platform, const char *path, const char *value)
+sysctl_set (NMPlatform *platform, const char *pathid, int dirfd, const char *path, const char *value)
 {
 	NMFakePlatformPrivate *priv = NM_FAKE_PLATFORM_GET_PRIVATE ((NMFakePlatform *) platform);
 
+	ASSERT_SYSCTL_ARGS (pathid, dirfd, path);
+
 	g_hash_table_insert (priv->options, g_strdup (path), g_strdup (value));
 
 	return TRUE;
 }
 
 static char *
-sysctl_get (NMPlatform *platform, const char *path)
+sysctl_get (NMPlatform *platform, const char *pathid, int dirfd, const char *path)
 {
 	NMFakePlatformPrivate *priv = NM_FAKE_PLATFORM_GET_PRIVATE ((NMFakePlatform *) platform);
 
+	ASSERT_SYSCTL_ARGS (pathid, dirfd, path);
+
 	return g_strdup (g_hash_table_lookup (priv->options, path));
 }
 
diff --git a/src/platform/nm-linux-platform.c b/src/platform/nm-linux-platform.c
index ab2ab9b017..7a7947c6d7 100644
--- a/src/platform/nm-linux-platform.c
+++ b/src/platform/nm-linux-platform.c
@@ -239,7 +239,7 @@ static void do_request_all_no_delayed_actions (NMPlatform *platform, DelayedActi
 static void cache_pre_hook (NMPCache *cache, const NMPObject *old, const NMPObject *new, NMPCacheOpsType ops_type, gpointer user_data);
 static void cache_prune_candidates_prune (NMPlatform *platform);
 static gboolean event_handler_read_netlink (NMPlatform *platform, gboolean wait_for_acks);
-static void _assert_netns_current (NMPlatform *platform);
+static void ASSERT_NETNS_CURRENT (NMPlatform *platform);
 
 /*****************************************************************************/
 
@@ -573,18 +573,14 @@ _lookup_cached_link (const NMPCache *cache, int ifindex, gboolean *completed_fro
 #define DEVTYPE_PREFIX "DEVTYPE="
 
 static char *
-_linktype_read_devtype (const char *ifname)
+_linktype_read_devtype (int dirfd)
 {
-	char uevent[NM_STRLEN ("/sys/class/net/123456789012345/uevent\0") + 100 /*safety*/];
 	char *contents = NULL;
 	char *cont, *end;
 
-	nm_sprintf_buf (uevent,
-	                "/sys/class/net/%s/uevent",
-	                NM_ASSERT_VALID_PATH_COMPONENT (ifname));
-	nm_assert (strlen (uevent) < sizeof (uevent) - 1);
+	nm_assert (dirfd >= 0);
 
-	if (!g_file_get_contents (uevent, &contents, NULL, NULL))
+	if (nm_utils_file_get_contents (dirfd, "uevent", 1*1024*1024, &contents, NULL, NULL) < 0)
 		return NULL;
 	for (cont = contents; cont; cont = end) {
 		end = strpbrk (cont, "\r\n");
@@ -614,7 +610,8 @@ _linktype_get_type (NMPlatform *platform,
 {
 	guint i;
 
-	_assert_netns_current (platform);
+	ASSERT_NETNS_CURRENT (platform);
+	nm_assert (ifname);
 
 	if (completed_from_cache) {
 		const NMPObject *obj;
@@ -635,7 +632,7 @@ _linktype_get_type (NMPlatform *platform,
 		 * of messing stuff up. */
 		if (   obj
 		    && !NM_IN_SET (obj->link.type, NM_LINK_TYPE_UNKNOWN, NM_LINK_TYPE_NONE)
-		    && !g_strcmp0 (ifname, obj->link.name)
+		    && nm_streq (ifname, obj->link.name)
 		    && (   !kind
 		        || !g_strcmp0 (kind, obj->link.kind))) {
 			nm_assert (obj->link.kind == g_intern_string (obj->link.kind));
@@ -656,7 +653,7 @@ _linktype_get_type (NMPlatform *platform,
 			NMPlatformTunProperties props;
 
 			if (   platform
-			    && nm_platform_link_tun_get_properties_ifname (platform, ifname, &props)) {
+			    && nm_platform_link_tun_get_properties (platform, ifindex, ifname, &props)) {
 				if (!g_strcmp0 (props.mode, "tap"))
 					return NM_LINK_TYPE_TAP;
 				if (!g_strcmp0 (props.mode, "tun"))
@@ -679,50 +676,52 @@ _linktype_get_type (NMPlatform *platform,
 	else if (arptype == ARPHRD_TUNNEL6)
 		return NM_LINK_TYPE_IP6TNL;
 
-	if (ifname) {
-		char anycast_mask[NM_STRLEN ("/sys/class/net/123456789012345/anycast_mask\0") + 100 /*safety*/];
-		gs_free char *driver = NULL;
-		gs_free char *devtype = NULL;
+	{
+		NMPUtilsEthtoolDriverInfo driver_info;
 
 		/* Fallback OVS detection for kernel <= 3.16 */
-		if (nmp_utils_ethtool_get_driver_info (ifname, &driver, NULL, NULL)) {
-			if (!g_strcmp0 (driver, "openvswitch"))
+		if (nmp_utils_ethtool_get_driver_info (ifindex, &driver_info)) {
+			if (nm_streq (driver_info.driver, "openvswitch"))
 				return NM_LINK_TYPE_OPENVSWITCH;
 
 			if (arptype == 256) {
 				/* Some s390 CTC-type devices report 256 for the encapsulation type
 				 * for some reason, but we need to call them Ethernet.
 				 */
-				if (!g_strcmp0 (driver, "ctcm"))
+				if (nm_streq (driver_info.driver, "ctcm"))
 					return NM_LINK_TYPE_ETHERNET;
 			}
 		}
+	}
 
-		nm_sprintf_buf (anycast_mask,
-		                "/sys/class/net/%s/anycast_mask",
-		                NM_ASSERT_VALID_PATH_COMPONENT (ifname));
-		nm_assert (strlen (anycast_mask) < sizeof (anycast_mask) - 1);
-
-		if (g_file_test (anycast_mask, G_FILE_TEST_EXISTS))
-			return NM_LINK_TYPE_OLPC_MESH;
-
-		devtype = _linktype_read_devtype (ifname);
-		for (i = 0; devtype && i < G_N_ELEMENTS (linktypes); i++) {
-			if (g_strcmp0 (devtype, linktypes[i].devtype) == 0) {
-				if (linktypes[i].nm_type == NM_LINK_TYPE_BNEP) {
-					/* Both BNEP and 6lowpan use DEVTYPE=bluetooth, so we must
-					 * use arptype to distinguish between them.
-					 */
-					if (arptype != ARPHRD_ETHER)
-						continue;
+	{
+		nm_auto_close int dirfd = -1;
+		gs_free char *devtype = NULL;
+		char ifname_verified[IFNAMSIZ];
+
+		dirfd = nmp_utils_sysctl_open_netdir (ifindex, ifname, ifname_verified);
+		if (dirfd >= 0) {
+			if (faccessat (dirfd, "anycast_mask", F_OK, 0) == 0)
+				return NM_LINK_TYPE_OLPC_MESH;
+
+			devtype = _linktype_read_devtype (dirfd);
+			for (i = 0; devtype && i < G_N_ELEMENTS (linktypes); i++) {
+				if (g_strcmp0 (devtype, linktypes[i].devtype) == 0) {
+					if (linktypes[i].nm_type == NM_LINK_TYPE_BNEP) {
+						/* Both BNEP and 6lowpan use DEVTYPE=bluetooth, so we must
+						 * use arptype to distinguish between them.
+						 */
+						if (arptype != ARPHRD_ETHER)
+							continue;
+					}
+					return linktypes[i].nm_type;
 				}
-				return linktypes[i].nm_type;
 			}
-		}
 
-		/* Fallback for drivers that don't call SET_NETDEV_DEVTYPE() */
-		if (wifi_utils_is_wifi (ifname))
-			return NM_LINK_TYPE_WIFI;
+			/* Fallback for drivers that don't call SET_NETDEV_DEVTYPE() */
+			if (wifi_utils_is_wifi (dirfd, ifname_verified))
+				return NM_LINK_TYPE_WIFI;
+		}
 
 		if (arptype == ARPHRD_ETHER) {
 			/* Misc non-upstream WWAN drivers.  rmnet is Qualcomm's proprietary
@@ -2481,50 +2480,66 @@ nm_linux_platform_setup (void)
 	              NULL);
 }
 
-/*****************************************************************************/
-
 static void
-_assert_netns_current (NMPlatform *platform)
+ASSERT_NETNS_CURRENT (NMPlatform *platform)
 {
-#if NM_MORE_ASSERTS
 	nm_assert (NM_IS_LINUX_PLATFORM (platform));
-
 	nm_assert (NM_IN_SET (nm_platform_netns_get (platform), NULL, nmp_netns_get_current ()));
-#endif
 }
 
+/*****************************************************************************/
+
+#define ASSERT_SYSCTL_ARGS(pathid, dirfd, path) \
+	G_STMT_START { \
+		const char *const _pathid = (pathid); \
+		const int _dirfd = (dirfd); \
+		const char *const _path = (path); \
+		\
+		nm_assert (_path && _path[0]); \
+		g_assert (!strstr (_path, "/../")); \
+		if (_dirfd < 0) { \
+			nm_assert (!_pathid); \
+			nm_assert (_path[0] == '/'); \
+			nm_assert (   g_str_has_prefix (_path, "/proc/sys/") \
+			           || g_str_has_prefix (_path, "/sys/")); \
+		} else { \
+			nm_assert (_pathid && _pathid[0] && _pathid[0] != '/'); \
+			nm_assert (_path[0] != '/'); \
+		} \
+	} G_STMT_END
+
 static void
-_log_dbg_sysctl_set_impl (NMPlatform *platform, const char *path, const char *value)
+_log_dbg_sysctl_set_impl (NMPlatform *platform, const char *pathid, int dirfd, const char *path, const char *value)
 {
 	GError *error = NULL;
 	char *contents, *contents_escaped;
 	char *value_escaped = g_strescape (value, NULL);
 
-	if (!g_file_get_contents (path, &contents, NULL, &error)) {
-		_LOGD ("sysctl: setting '%s' to '%s' (current value cannot be read: %s)", path, value_escaped, error->message);
+	if (nm_utils_file_get_contents (dirfd, path, 1*1024*1024, &contents, NULL, &error) < 0) {
+		_LOGD ("sysctl: setting '%s' to '%s' (current value cannot be read: %s)", pathid, value_escaped, error->message);
 		g_clear_error (&error);
 	} else {
 		g_strstrip (contents);
 		contents_escaped = g_strescape (contents, NULL);
 		if (strcmp (contents, value) == 0)
-			_LOGD ("sysctl: setting '%s' to '%s' (current value is identical)", path, value_escaped);
+			_LOGD ("sysctl: setting '%s' to '%s' (current value is identical)", pathid, value_escaped);
 		else
-			_LOGD ("sysctl: setting '%s' to '%s' (current value is '%s')", path, value_escaped, contents_escaped);
+			_LOGD ("sysctl: setting '%s' to '%s' (current value is '%s')", pathid, value_escaped, contents_escaped);
 		g_free (contents);
 		g_free (contents_escaped);
 	}
 	g_free (value_escaped);
 }
 
-#define _log_dbg_sysctl_set(platform, path, value) \
+#define _log_dbg_sysctl_set(platform, pathid, dirfd, path, value) \
 	G_STMT_START { \
 		if (_LOGD_ENABLED ()) { \
-			_log_dbg_sysctl_set_impl (platform, path, value); \
+			_log_dbg_sysctl_set_impl (platform, pathid, dirfd, path, value); \
 		} \
 	} G_STMT_END
 
 static gboolean
-sysctl_set (NMPlatform *platform, const char *path, const char *value)
+sysctl_set (NMPlatform *platform, const char *pathid, int dirfd, const char *path, const char *value)
 {
 	nm_auto_pop_netns NMPNetns *netns = NULL;
 	int fd, tries;
@@ -2537,32 +2552,46 @@ sysctl_set (NMPlatform *platform, const char *path, const char *value)
 	g_return_val_if_fail (path != NULL, FALSE);
 	g_return_val_if_fail (value != NULL, FALSE);
 
-	/* Don't write outside known locations */
-	g_assert (g_str_has_prefix (path, "/proc/sys/")
-	          || g_str_has_prefix (path, "/sys/"));
-	/* Don't write to suspicious locations */
-	g_assert (!strstr (path, "/../"));
+	ASSERT_SYSCTL_ARGS (pathid, dirfd, path);
 
-	if (!nm_platform_netns_push (platform, &netns)) {
-		errno = ENETDOWN;
-		return FALSE;
-	}
+	if (dirfd < 0) {
+		if (!nm_platform_netns_push (platform, &netns)) {
+			errno = ENETDOWN;
+			return FALSE;
+		}
 
-	fd = open (path, O_WRONLY | O_TRUNC);
-	if (fd == -1) {
-		errsv = errno;
-		if (errsv == ENOENT) {
-			_LOGD ("sysctl: failed to open '%s': (%d) %s",
-			       path, errsv, strerror (errsv));
-		} else {
-			_LOGE ("sysctl: failed to open '%s': (%d) %s",
-			       path, errsv, strerror (errsv));
+		pathid = path;
+
+		fd = open (path, O_WRONLY | O_TRUNC | O_CLOEXEC);
+		if (fd == -1) {
+			errsv = errno;
+			if (errsv == ENOENT) {
+				_LOGD ("sysctl: failed to open '%s': (%d) %s",
+				       pathid, errsv, strerror (errsv));
+			} else {
+				_LOGE ("sysctl: failed to open '%s': (%d) %s",
+				       pathid, errsv, strerror (errsv));
+			}
+			errno = errsv;
+			return FALSE;
+		}
+	} else {
+		fd = openat (dirfd, path, O_WRONLY | O_TRUNC | O_CLOEXEC);
+		if (fd == -1) {
+			errsv = errno;
+			if (errsv == ENOENT) {
+				_LOGD ("sysctl: failed to openat '%s': (%d) %s",
+				       pathid, errsv, strerror (errsv));
+			} else {
+				_LOGE ("sysctl: failed to openat '%s': (%d) %s",
+				       pathid, errsv, strerror (errsv));
+			}
+			errno = errsv;
+			return FALSE;
 		}
-		errno = errsv;
-		return FALSE;
 	}
 
-	_log_dbg_sysctl_set (platform, path, value);
+	_log_dbg_sysctl_set (platform, pathid, dirfd, path, value);
 
 	/* Most sysfs and sysctl options don't care about a trailing LF, while some
 	 * (like infiniband) do.  So always add the LF.  Also, neither sysfs nor
@@ -2635,7 +2664,7 @@ _nm_logging_clear_platform_logging_cache_impl (void)
 }
 
 static void
-_log_dbg_sysctl_get_impl (NMPlatform *platform, const char *path, const char *contents)
+_log_dbg_sysctl_get_impl (NMPlatform *platform, const char *pathid, const char *contents)
 {
 	NMLinuxPlatformPrivate *priv = NM_LINUX_PLATFORM_GET_PRIVATE (platform);
 	const char *prev_value = NULL;
@@ -2645,24 +2674,24 @@ _log_dbg_sysctl_get_impl (NMPlatform *platform, const char *path, const char *co
 		sysctl_clear_cache_list = g_slist_prepend (sysctl_clear_cache_list, platform);
 		priv->sysctl_get_prev_values = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
 	} else
-		prev_value = g_hash_table_lookup (priv->sysctl_get_prev_values, path);
+		prev_value = g_hash_table_lookup (priv->sysctl_get_prev_values, pathid);
 
 	if (prev_value) {
 		if (strcmp (prev_value, contents) != 0) {
 			char *contents_escaped = g_strescape (contents, NULL);
 			char *prev_value_escaped = g_strescape (prev_value, NULL);
 
-			_LOGD ("sysctl: reading '%s': '%s' (changed from '%s' on last read)", path, contents_escaped, prev_value_escaped);
+			_LOGD ("sysctl: reading '%s': '%s' (changed from '%s' on last read)", pathid, contents_escaped, prev_value_escaped);
 			g_free (contents_escaped);
 			g_free (prev_value_escaped);
-			g_hash_table_insert (priv->sysctl_get_prev_values, g_strdup (path), g_strdup (contents));
+			g_hash_table_insert (priv->sysctl_get_prev_values, g_strdup (pathid), g_strdup (contents));
 		}
 	} else {
 		char *contents_escaped = g_strescape (contents, NULL);
 
-		_LOGD ("sysctl: reading '%s': '%s'", path, contents_escaped);
+		_LOGD ("sysctl: reading '%s': '%s'", pathid, contents_escaped);
 		g_free (contents_escaped);
-		g_hash_table_insert (priv->sysctl_get_prev_values, g_strdup (path), g_strdup (contents));
+		g_hash_table_insert (priv->sysctl_get_prev_values, g_strdup (pathid), g_strdup (contents));
 	}
 
 	if (   !priv->sysctl_get_warned
@@ -2672,43 +2701,42 @@ _log_dbg_sysctl_get_impl (NMPlatform *platform, const char *path, const char *co
 	}
 }
 
-#define _log_dbg_sysctl_get(platform, path, contents) \
+#define _log_dbg_sysctl_get(platform, pathid, contents) \
 	G_STMT_START { \
 		if (_LOGD_ENABLED ()) \
-			_log_dbg_sysctl_get_impl (platform, path, contents); \
+			_log_dbg_sysctl_get_impl (platform, pathid, contents); \
 	} G_STMT_END
 
 static char *
-sysctl_get (NMPlatform *platform, const char *path)
+sysctl_get (NMPlatform *platform, const char *pathid, int dirfd, const char *path)
 {
 	nm_auto_pop_netns NMPNetns *netns = NULL;
 	GError *error = NULL;
 	char *contents;
 
-	/* Don't write outside known locations */
-	g_assert (g_str_has_prefix (path, "/proc/sys/")
-	          || g_str_has_prefix (path, "/sys/"));
-	/* Don't write to suspicious locations */
-	g_assert (!strstr (path, "/../"));
+	ASSERT_SYSCTL_ARGS (pathid, dirfd, path);
 
-	if (!nm_platform_netns_push (platform, &netns))
-		return NULL;
+	if (dirfd < 0) {
+		if (!nm_platform_netns_push (platform, &netns))
+			return NULL;
+		pathid = path;
+	}
 
-	if (!g_file_get_contents (path, &contents, NULL, &error)) {
+	if (nm_utils_file_get_contents (dirfd, path, 1*1024*1024, &contents, NULL, &error) < 0) {
 		/* We assume FAILED means EOPNOTSUP */
 		if (   g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT)
 		    || g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NODEV)
 		    || g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_FAILED))
-			_LOGD ("error reading %s: %s", path, error->message);
+			_LOGD ("error reading %s: %s", pathid, error->message);
 		else
-			_LOGE ("error reading %s: %s", path, error->message);
+			_LOGE ("error reading %s: %s", pathid, error->message);
 		g_clear_error (&error);
 		return NULL;
 	}
 
 	g_strstrip (contents);
 
-	_log_dbg_sysctl_get (platform, path, contents);
+	_log_dbg_sysctl_get (platform, pathid, contents);
 
 	return contents;
 }
@@ -2763,8 +2791,7 @@ do_emit_signal (NMPlatform *platform, const NMPObject *obj, NMPCacheOpsType cach
 	nm_assert (!obj || cache_op == NMP_CACHE_OPS_REMOVED || obj == nmp_cache_lookup_obj (NM_LINUX_PLATFORM_GET_PRIVATE (platform)->cache, obj));
 	nm_assert (!obj || cache_op != NMP_CACHE_OPS_REMOVED || obj != nmp_cache_lookup_obj (NM_LINUX_PLATFORM_GET_PRIVATE (platform)->cache, obj));
 
-	/* we raise the signals inside the namespace of the NMPlatform instance. */
-	_assert_netns_current (platform);
+	ASSERT_NETNS_CURRENT (platform);
 
 	switch (cache_op) {
 	case NMP_CACHE_OPS_ADDED:
@@ -4428,10 +4455,6 @@ static gboolean
 link_supports_carrier_detect (NMPlatform *platform, int ifindex)
 {
 	nm_auto_pop_netns NMPNetns *netns = NULL;
-	const char *name = nm_platform_link_get_name (platform, ifindex);
-
-	if (!name)
-		return FALSE;
 
 	if (!nm_platform_netns_push (platform, &netns))
 		return FALSE;
@@ -4440,7 +4463,7 @@ link_supports_carrier_detect (NMPlatform *platform, int ifindex)
 	 * us whether the device actually supports carrier detection in the first
 	 * place. We assume any device that does implements one of these two APIs.
 	 */
-	return nmp_utils_ethtool_supports_carrier_detect (name) || nmp_utils_mii_supports_carrier_detect (name);
+	return nmp_utils_ethtool_supports_carrier_detect (ifindex) || nmp_utils_mii_supports_carrier_detect (ifindex);
 }
 
 static gboolean
@@ -4458,7 +4481,7 @@ link_supports_vlans (NMPlatform *platform, int ifindex)
 	if (!nm_platform_netns_push (platform, &netns))
 		return FALSE;
 
-	return nmp_utils_ethtool_supports_vlans (obj->link.name);
+	return nmp_utils_ethtool_supports_vlans (ifindex);
 }
 
 static NMPlatformError
@@ -4526,7 +4549,7 @@ link_get_permanent_address (NMPlatform *platform,
 	if (!nm_platform_netns_push (platform, &netns))
 		return FALSE;
 
-	return nmp_utils_ethtool_get_permanent_address (nm_platform_link_get_name (platform, ifindex), buf, length);
+	return nmp_utils_ethtool_get_permanent_address (ifindex, buf, length);
 }
 
 static gboolean
@@ -4555,44 +4578,27 @@ nla_put_failure:
 static char *
 link_get_physical_port_id (NMPlatform *platform, int ifindex)
 {
-	const char *ifname;
-	char *path, *id;
+	nm_auto_close int dirfd = -1;
+	char ifname_verified[IFNAMSIZ];
 
-	ifname = nm_platform_link_get_name (platform, ifindex);
-	if (!ifname)
+	dirfd = nm_platform_sysctl_open_netdir (platform, ifindex, ifname_verified);
+	if (dirfd < 0)
 		return NULL;
-
-	ifname = NM_ASSERT_VALID_PATH_COMPONENT (ifname);
-
-	path = g_strdup_printf ("/sys/class/net/%s/phys_port_id", ifname);
-	id = sysctl_get (platform, path);
-	g_free (path);
-
-	return id;
+	return sysctl_get (platform, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_verified, "phys_port_id"));
 }
 
 static guint
 link_get_dev_id (NMPlatform *platform, int ifindex)
 {
-	const char *ifname;
-	gs_free char *path = NULL, *id = NULL;
-	gint64 int_val;
-
-	ifname = nm_platform_link_get_name (platform, ifindex);
-	if (!ifname)
-		return 0;
-
-	ifname = NM_ASSERT_VALID_PATH_COMPONENT (ifname);
+	nm_auto_close int dirfd = -1;
+	char ifname_verified[IFNAMSIZ];
 
-	path = g_strdup_printf ("/sys/class/net/%s/dev_id", ifname);
-	id = sysctl_get (platform, path);
-	if (!id || !*id)
+	dirfd = nm_platform_sysctl_open_netdir (platform, ifindex, ifname_verified);
+	if (dirfd < 0)
 		return 0;
-
-	/* Value is reported as hex */
-	int_val = _nm_utils_ascii_str_to_int64 (id, 16, 0, G_MAXUINT16, 0);
-
-	return errno ? 0 : (int) int_val;
+	return nm_platform_sysctl_get_int_checked (platform,
+	                                           NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_verified, "dev_id"),
+	                                           16, 0, G_MAXUINT16, 0);
 }
 
 static int
@@ -5161,7 +5167,7 @@ tun_add (NMPlatform *platform, const char *name, gboolean tap,
 	_LOGD ("link: add %s '%s' owner %" G_GINT64_FORMAT " group %" G_GINT64_FORMAT,
 	       tap ? "tap" : "tun", name, owner, group);
 
-	fd = open ("/dev/net/tun", O_RDWR);
+	fd = open ("/dev/net/tun", O_RDWR | O_CLOEXEC);
 	if (fd < 0)
 		return FALSE;
 
@@ -5250,9 +5256,9 @@ _infiniband_partition_action (NMPlatform *platform,
                               const NMPlatformLink **out_link)
 {
 	NMLinuxPlatformPrivate *priv = NM_LINUX_PLATFORM_GET_PRIVATE (platform);
-	const NMPObject *obj_parent;
+	nm_auto_close int dirfd = -1;
+	char ifname_parent[IFNAMSIZ];
 	const NMPObject *obj;
-	char path[NM_STRLEN ("/sys/class/net/%s/%s") + IFNAMSIZ + 100];
 	char id[20];
 	char name[IFNAMSIZ];
 	gboolean success;
@@ -5260,20 +5266,18 @@ _infiniband_partition_action (NMPlatform *platform,
 	nm_assert (NM_IN_SET (action, INFINIBAND_ACTION_CREATE_CHILD, INFINIBAND_ACTION_DELETE_CHILD));
 	nm_assert (p_key > 0 && p_key <= 0xffff && p_key != 0x8000);
 
-	obj_parent = nmp_cache_lookup_link (priv->cache, parent);
-	if (!obj_parent || !obj_parent->link.name[0]) {
+	dirfd = nm_platform_sysctl_open_netdir (platform, parent, ifname_parent);
+	if (dirfd < 0) {
 		errno = ENOENT;
 		return FALSE;
 	}
 
-	nm_sprintf_buf (path,
-	                "/sys/class/net/%s/%s",
-	                NM_ASSERT_VALID_PATH_COMPONENT (obj_parent->link.name),
-	                (action == INFINIBAND_ACTION_CREATE_CHILD
-	                     ? "create_child"
-	                     : "delete_child"));
 	nm_sprintf_buf (id, "0x%04x", p_key);
-	success = nm_platform_sysctl_set (platform, path, id);
+	if (action == INFINIBAND_ACTION_CREATE_CHILD)
+		success = nm_platform_sysctl_set (platform, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_parent, "create_child"), id);
+	else
+		success = nm_platform_sysctl_set (platform, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_parent, "delete_child"), id);
+
 	if (!success) {
 		if (   action == INFINIBAND_ACTION_DELETE_CHILD
 		    && errno == ENODEV)
@@ -5281,7 +5285,7 @@ _infiniband_partition_action (NMPlatform *platform,
 		return FALSE;
 	}
 
-	nm_utils_new_infiniband_name (name, obj_parent->link.name, p_key);
+	nm_utils_new_infiniband_name (name, ifname_parent, p_key);
 	do_request_link (platform, 0, name);
 
 	if (action == INFINIBAND_ACTION_DELETE_CHILD)
@@ -5515,7 +5519,7 @@ link_get_wake_on_lan (NMPlatform *platform, int ifindex)
 		return FALSE;
 
 	if (type == NM_LINK_TYPE_ETHERNET)
-		return nmp_utils_ethtool_get_wake_on_lan (nm_platform_link_get_name (platform, ifindex));
+		return nmp_utils_ethtool_get_wake_on_lan (ifindex);
 	else if (type == NM_LINK_TYPE_WIFI) {
 		WifiData *wifi_data = wifi_get_wifi_data (platform, ifindex);
 
@@ -5535,14 +5539,17 @@ link_get_driver_info (NMPlatform *platform,
                       char **out_fw_version)
 {
 	nm_auto_pop_netns NMPNetns *netns = NULL;
+	NMPUtilsEthtoolDriverInfo driver_info;
 
 	if (!nm_platform_netns_push (platform, &netns))
 		return FALSE;
 
-	return nmp_utils_ethtool_get_driver_info (nm_platform_link_get_name (platform, ifindex),
-	                                          out_driver_name,
-	                                          out_driver_version,
-	                                          out_fw_version);
+	if (!nmp_utils_ethtool_get_driver_info (ifindex, &driver_info))
+		return FALSE;
+	NM_SET_OUT (out_driver_name,    g_strdup (driver_info.driver));
+	NM_SET_OUT (out_driver_version, g_strdup (driver_info.version));
+	NM_SET_OUT (out_fw_version,     g_strdup (driver_info.fw_version));
+	return TRUE;
 }
 
 /*****************************************************************************/
diff --git a/src/platform/nm-platform-utils.c b/src/platform/nm-platform-utils.c
index 9ef0707d58..8b6994e20e 100644
--- a/src/platform/nm-platform-utils.c
+++ b/src/platform/nm-platform-utils.c
@@ -31,15 +31,39 @@
 #include <linux/mii.h>
 #include <linux/version.h>
 #include <linux/rtnetlink.h>
+#include <fcntl.h>
 
 #include "nm-utils.h"
 #include "nm-setting-wired.h"
 
 #include "nm-core-utils.h"
 
+extern char *if_indextoname (unsigned int __ifindex, char *__ifname);
+
 /******************************************************************
  * ethtool
  ******************************************************************/
+
+NM_UTILS_ENUM2STR_DEFINE_STATIC (_ethtool_cmd_to_string, guint32,
+	NM_UTILS_ENUM2STR (ETHTOOL_GDRVINFO,   "ETHTOOL_GDRVINFO"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GFEATURES,  "ETHTOOL_GFEATURES"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GLINK,      "ETHTOOL_GLINK"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GPERMADDR,  "ETHTOOL_GPERMADDR"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GSET,       "ETHTOOL_GSET"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GSSET_INFO, "ETHTOOL_GSSET_INFO"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GSTATS,     "ETHTOOL_GSTATS"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GSTRINGS,   "ETHTOOL_GSTRINGS"),
+	NM_UTILS_ENUM2STR (ETHTOOL_GWOL,       "ETHTOOL_GWOL"),
+	NM_UTILS_ENUM2STR (ETHTOOL_SSET,       "ETHTOOL_SSET"),
+	NM_UTILS_ENUM2STR (ETHTOOL_SWOL,       "ETHTOOL_SWOL"),
+);
+
+static const char *
+_ethtool_data_to_string (gconstpointer edata, char *buf, gsize len)
+{
+	return _ethtool_cmd_to_string (*((guint32 *) edata), buf, len);
+}
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
 #define ethtool_cmd_speed(pedata) ((pedata)->speed)
 
@@ -47,55 +71,84 @@
 	G_STMT_START { (pedata)->speed = (guint16) (speed); } G_STMT_END
 #endif
 
-
 static gboolean
-ethtool_get (const char *name, gpointer edata)
+ethtool_get (int ifindex, gpointer edata)
 {
-	struct ifreq ifr;
-	int fd;
+	char ifname[IFNAMSIZ];
+	char sbuf[50];
 
-	if (!name || !*name)
-		return FALSE;
+	nm_assert (ifindex > 0);
 
-	if (!nmp_utils_device_exists (name))
+	/* ethtool ioctl API uses the ifname to refer to an interface. That is racy
+	 * as interfaces can be renamed *sigh*.
+	 *
+	 * Note that we anyway have to verify whether the interface exists, before
+	 * calling ioctl for a non-existing ifname. This is to prevent autoloading
+	 * of kernel modules *sigh*.
+	 * Thus, as we anyway verify the existence of ifname before doing the call,
+	 * go one step further and lookup the ifname everytime anew.
+	 *
+	 * This does not solve the renaming race, but it minimizes the time for
+	 * the race to happen as much as possible. */
+
+	if (!if_indextoname (ifindex, ifname)) {
+		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s: request fails resolving ifindex: %s",
+		              ifindex,
+		              _ethtool_data_to_string (edata, sbuf, sizeof (sbuf)),
+		              g_strerror (errno));
 		return FALSE;
+	}
 
-	/* nmp_utils_device_exists() already errors out if @name is invalid. */
-	nm_assert (strlen (name) < IFNAMSIZ);
-
-	memset (&ifr, 0, sizeof (ifr));
-	nm_utils_ifname_cpy (ifr.ifr_name, name);
-	ifr.ifr_data = edata;
+	{
+		nm_auto_close int fd = -1;
+		struct ifreq ifr = {
+			.ifr_data = edata,
+		};
+
+		memcpy (ifr.ifr_name, ifname, sizeof (ifname));
+
+		fd = socket (PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+		if (fd < 0) {
+			nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s, %s: failed creating socket for ioctl: %s",
+			              ifindex,
+			              _ethtool_data_to_string (edata, sbuf, sizeof (sbuf)),
+			              ifname,
+			              g_strerror (errno));
+			return FALSE;
+		}
 
-	fd = socket (PF_INET, SOCK_DGRAM, 0);
-	if (fd < 0) {
-		nm_log_err (LOGD_PLATFORM, "ethtool: Could not open socket.");
-		return FALSE;
-	}
+		if (ioctl (fd, SIOCETHTOOL, &ifr) < 0) {
+			nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s, %s: failed: %s",
+			              ifindex,
+			              _ethtool_data_to_string (edata, sbuf, sizeof (sbuf)),
+			              ifname,
+			              strerror (errno));
+			return FALSE;
+		}
 
-	if (ioctl (fd, SIOCETHTOOL, &ifr) < 0) {
-		nm_log_dbg (LOGD_PLATFORM, "ethtool: Request failed: %s", strerror (errno));
-		close (fd);
-		return FALSE;
+		nm_log_trace (LOGD_PLATFORM, "ethtool[%d]: %s, %s: success",
+		              ifindex,
+		              _ethtool_data_to_string (edata, sbuf, sizeof (sbuf)),
+		              ifname);
+		return TRUE;
 	}
-
-	close (fd);
-	return TRUE;
 }
 
 static int
-ethtool_get_stringset_index (const char *ifname, int stringset_id, const char *string)
+ethtool_get_stringset_index (int ifindex, int stringset_id, const char *string)
 {
 	gs_free struct ethtool_sset_info *info = NULL;
 	gs_free struct ethtool_gstrings *strings = NULL;
 	guint32 len, i;
 
+	g_return_val_if_fail (ifindex > 0, -1);
+
 	info = g_malloc0 (sizeof (*info) + sizeof (guint32));
 	info->cmd = ETHTOOL_GSSET_INFO;
 	info->reserved = 0;
 	info->sset_mask = 1ULL << stringset_id;
 
-	if (!ethtool_get (ifname, info))
+	if (!ethtool_get (ifindex, info))
 		return -1;
 	if (!info->sset_mask)
 		return -1;
@@ -106,7 +159,7 @@ ethtool_get_stringset_index (const char *ifname, int stringset_id, const char *s
 	strings->cmd = ETHTOOL_GSTRINGS;
 	strings->string_set = stringset_id;
 	strings->len = len;
-	if (!ethtool_get (ifname, strings))
+	if (!ethtool_get (ifindex, strings))
 		return -1;
 
 	for (i = 0; i < len; i++) {
@@ -118,32 +171,30 @@ ethtool_get_stringset_index (const char *ifname, int stringset_id, const char *s
 }
 
 gboolean
-nmp_utils_ethtool_get_driver_info (const char *ifname,
-                                   char **out_driver_name,
-                                   char **out_driver_version,
-                                   char **out_fw_version)
+nmp_utils_ethtool_get_driver_info (int ifindex,
+                                   NMPUtilsEthtoolDriverInfo *data)
 {
-	struct ethtool_drvinfo drvinfo = { 0 };
-
-	if (!ifname)
-		return FALSE;
-
-	drvinfo.cmd = ETHTOOL_GDRVINFO;
-	if (!ethtool_get (ifname, &drvinfo))
-		return FALSE;
-
-	if (out_driver_name)
-		*out_driver_name = g_strdup (drvinfo.driver);
-	if (out_driver_version)
-		*out_driver_version = g_strdup (drvinfo.version);
-	if (out_fw_version)
-		*out_fw_version = g_strdup (drvinfo.fw_version);
-
-	return TRUE;
+	struct ethtool_drvinfo *drvinfo;
+	G_STATIC_ASSERT (sizeof (*data) == sizeof (*drvinfo));
+	G_STATIC_ASSERT (offsetof (NMPUtilsEthtoolDriverInfo, driver)     == offsetof (struct ethtool_drvinfo, driver));
+	G_STATIC_ASSERT (offsetof (NMPUtilsEthtoolDriverInfo, version)    == offsetof (struct ethtool_drvinfo, version));
+	G_STATIC_ASSERT (offsetof (NMPUtilsEthtoolDriverInfo, fw_version) == offsetof (struct ethtool_drvinfo, fw_version));
+	G_STATIC_ASSERT (sizeof (data->driver)     == sizeof (drvinfo->driver));
+	G_STATIC_ASSERT (sizeof (data->version)    == sizeof (drvinfo->version));
+	G_STATIC_ASSERT (sizeof (data->fw_version) == sizeof (drvinfo->fw_version));
+
+	g_return_val_if_fail (ifindex > 0, FALSE);
+	g_return_val_if_fail (data, FALSE);
+
+	drvinfo = (struct ethtool_drvinfo *) data;
+
+	memset (drvinfo, 0, sizeof (*drvinfo));
+	drvinfo->cmd = ETHTOOL_GDRVINFO;
+	return ethtool_get (ifindex, drvinfo);
 }
 
 gboolean
-nmp_utils_ethtool_get_permanent_address (const char *ifname,
+nmp_utils_ethtool_get_permanent_address (int ifindex,
                                          guint8 *buf,
                                          size_t *length)
 {
@@ -153,14 +204,13 @@ nmp_utils_ethtool_get_permanent_address (const char *ifname,
 	} edata;
 	guint i;
 
-	if (!ifname)
-		return FALSE;
+	g_return_val_if_fail (ifindex > 0, FALSE);
 
 	memset (&edata, 0, sizeof (edata));
 	edata.e.cmd = ETHTOOL_GPERMADDR;
 	edata.e.size = NM_UTILS_HWADDR_LEN_MAX;
 
-	if (!ethtool_get (ifname, &edata.e))
+	if (!ethtool_get (ifindex, &edata.e))
 		return FALSE;
 
 	if (edata.e.size > NM_UTILS_HWADDR_LEN_MAX)
@@ -187,29 +237,30 @@ not_all_0or1:
 }
 
 gboolean
-nmp_utils_ethtool_supports_carrier_detect (const char *ifname)
+nmp_utils_ethtool_supports_carrier_detect (int ifindex)
 {
 	struct ethtool_cmd edata = { .cmd = ETHTOOL_GLINK };
 
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
 	/* We ignore the result. If the ETHTOOL_GLINK call succeeded, then we
 	 * assume the device supports carrier-detect, otherwise we assume it
 	 * doesn't.
 	 */
-	return ethtool_get (ifname, &edata);
+	return ethtool_get (ifindex, &edata);
 }
 
 gboolean
-nmp_utils_ethtool_supports_vlans (const char *ifname)
+nmp_utils_ethtool_supports_vlans (int ifindex)
 {
 	gs_free struct ethtool_gfeatures *features = NULL;
 	int idx, block, bit, size;
 
-	if (!ifname)
-		return FALSE;
+	g_return_val_if_fail (ifindex > 0, FALSE);
 
-	idx = ethtool_get_stringset_index (ifname, ETH_SS_FEATURES, "vlan-challenged");
+	idx = ethtool_get_stringset_index (ifindex, ETH_SS_FEATURES, "vlan-challenged");
 	if (idx == -1) {
-		nm_log_dbg (LOGD_PLATFORM, "ethtool: vlan-challenged ethtool feature does not exist for %s?", ifname);
+		nm_log_dbg (LOGD_PLATFORM, "ethtool: vlan-challenged ethtool feature does not exist for %d?", ifindex);
 		return FALSE;
 	}
 
@@ -221,54 +272,52 @@ nmp_utils_ethtool_supports_vlans (const char *ifname)
 	features->cmd = ETHTOOL_GFEATURES;
 	features->size = size;
 
-	if (!ethtool_get (ifname, features))
+	if (!ethtool_get (ifindex, features))
 		return FALSE;
 
 	return !(features->features[block].active & (1 << bit));
 }
 
 int
-nmp_utils_ethtool_get_peer_ifindex (const char *ifname)
+nmp_utils_ethtool_get_peer_ifindex (int ifindex)
 {
 	gs_free struct ethtool_stats *stats = NULL;
 	int peer_ifindex_stat;
 
-	if (!ifname)
-		return 0;
+	g_return_val_if_fail (ifindex > 0, 0);
 
-	peer_ifindex_stat = ethtool_get_stringset_index (ifname, ETH_SS_STATS, "peer_ifindex");
+	peer_ifindex_stat = ethtool_get_stringset_index (ifindex, ETH_SS_STATS, "peer_ifindex");
 	if (peer_ifindex_stat == -1) {
-		nm_log_dbg (LOGD_PLATFORM, "ethtool: peer_ifindex stat for %s does not exist?", ifname);
+		nm_log_dbg (LOGD_PLATFORM, "ethtool: peer_ifindex stat for %d does not exist?", ifindex);
 		return FALSE;
 	}
 
 	stats = g_malloc0 (sizeof (*stats) + (peer_ifindex_stat + 1) * sizeof (guint64));
 	stats->cmd = ETHTOOL_GSTATS;
 	stats->n_stats = peer_ifindex_stat + 1;
-	if (!ethtool_get (ifname, stats))
+	if (!ethtool_get (ifindex, stats))
 		return 0;
 
 	return stats->data[peer_ifindex_stat];
 }
 
 gboolean
-nmp_utils_ethtool_get_wake_on_lan (const char *ifname)
+nmp_utils_ethtool_get_wake_on_lan (int ifindex)
 {
 	struct ethtool_wolinfo wol;
 
-	if (!ifname)
-		return FALSE;
+	g_return_val_if_fail (ifindex > 0, FALSE);
 
 	memset (&wol, 0, sizeof (wol));
 	wol.cmd = ETHTOOL_GWOL;
-	if (!ethtool_get (ifname, &wol))
+	if (!ethtool_get (ifindex, &wol))
 		return FALSE;
 
 	return wol.wolopts != 0;
 }
 
 gboolean
-nmp_utils_ethtool_get_link_settings (const char *ifname,
+nmp_utils_ethtool_get_link_settings (int ifindex,
                                      gboolean *out_autoneg,
                                      guint32 *out_speed,
                                      NMPlatformLinkDuplexType *out_duplex)
@@ -277,7 +326,9 @@ nmp_utils_ethtool_get_link_settings (const char *ifname,
 		.cmd = ETHTOOL_GSET,
 	};
 
-	if (!ethtool_get (ifname, &edata))
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
+	if (!ethtool_get (ifindex, &edata))
 		return FALSE;
 
 	if (out_autoneg)
@@ -311,14 +362,19 @@ nmp_utils_ethtool_get_link_settings (const char *ifname,
 }
 
 gboolean
-nmp_utils_ethtool_set_link_settings (const char *ifname, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex)
+nmp_utils_ethtool_set_link_settings (int ifindex,
+                                     gboolean autoneg,
+                                     guint32 speed,
+                                     NMPlatformLinkDuplexType duplex)
 {
 	struct ethtool_cmd edata = {
 		.cmd = ETHTOOL_GSET,
 	};
 
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
 	/* retrieve first current settings */
-	if (!ethtool_get (ifname, &edata))
+	if (!ethtool_get (ifindex, &edata))
 		return FALSE;
 
 	/* then change the needed ones */
@@ -346,16 +402,18 @@ nmp_utils_ethtool_set_link_settings (const char *ifname, gboolean autoneg, guint
 		}
 	}
 
-	return ethtool_get (ifname, &edata);
+	return ethtool_get (ifindex, &edata);
 }
 
 gboolean
-nmp_utils_ethtool_set_wake_on_lan (const char *ifname,
+nmp_utils_ethtool_set_wake_on_lan (int ifindex,
                                    NMSettingWiredWakeOnLan wol,
                                    const char *wol_password)
 {
 	struct ethtool_wolinfo wol_info = { };
 
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
 	if (wol == NM_SETTING_WIRED_WAKE_ON_LAN_IGNORE)
 		return TRUE;
 
@@ -386,7 +444,7 @@ nmp_utils_ethtool_set_wake_on_lan (const char *ifname,
 		wol_info.wolopts |= WAKE_MAGICSECURE;
 	}
 
-	return ethtool_get (ifname, &wol_info);
+	return ethtool_get (ifindex, &wol_info);
 }
 
 /******************************************************************
@@ -394,51 +452,45 @@ nmp_utils_ethtool_set_wake_on_lan (const char *ifname,
  ******************************************************************/
 
 gboolean
-nmp_utils_mii_supports_carrier_detect (const char *ifname)
+nmp_utils_mii_supports_carrier_detect (int ifindex)
 {
-	int fd, errsv;
+	char ifname[IFNAMSIZ];
+	nm_auto_close int fd = -1;
 	struct ifreq ifr;
 	struct mii_ioctl_data *mii;
-	gboolean supports_mii = FALSE;
 
-	if (!ifname)
-		return FALSE;
+	g_return_val_if_fail (ifindex > 0, FALSE);
 
-	if (!nmp_utils_device_exists (ifname))
+	if (!if_indextoname (ifindex, ifname)) {
+		nm_log_trace (LOGD_PLATFORM, "mii[%d]: carrier-detect no: request fails resolving ifindex: %s", ifindex, g_strerror (errno));
 		return FALSE;
+	}
 
-	fd = socket (PF_INET, SOCK_DGRAM, 0);
+	fd = socket (PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	if (fd < 0) {
-		nm_log_err (LOGD_PLATFORM, "mii: couldn't open control socket (%s)", ifname);
+		nm_log_trace (LOGD_PLATFORM, "mii[%d,%s]: carrier-detect no: couldn't open control socket: %s", ifindex, ifname, g_strerror (errno));
 		return FALSE;
 	}
 
 	memset (&ifr, 0, sizeof (struct ifreq));
-	nm_utils_ifname_cpy (ifr.ifr_name, ifname);
+	memcpy (ifr.ifr_name, ifname, IFNAMSIZ);
 
-	errno = 0;
 	if (ioctl (fd, SIOCGMIIPHY, &ifr) < 0) {
-		errsv = errno;
-		nm_log_dbg (LOGD_PLATFORM, "mii: SIOCGMIIPHY failed: %s (%d) (%s)", strerror (errsv), errsv, ifname);
-		goto out;
+		nm_log_trace (LOGD_PLATFORM, "mii[%d,%s]: carrier-detect no: SIOCGMIIPHY failed: %s", ifindex, ifname, strerror (errno));
+		return FALSE;
 	}
 
 	/* If we can read the BMSR register, we assume that the card supports MII link detection */
 	mii = (struct mii_ioctl_data *) &ifr.ifr_ifru;
 	mii->reg_num = MII_BMSR;
 
-	if (ioctl (fd, SIOCGMIIREG, &ifr) == 0) {
-		nm_log_dbg (LOGD_PLATFORM, "mii: SIOCGMIIREG result 0x%X (%s)", mii->val_out, ifname);
-		supports_mii = TRUE;
-	} else {
-		errsv = errno;
-		nm_log_dbg (LOGD_PLATFORM, "mii: SIOCGMIIREG failed: %s (%d) (%s)", strerror (errsv), errsv, ifname);
+	if (ioctl (fd, SIOCGMIIREG, &ifr) != 0) {
+		nm_log_trace (LOGD_PLATFORM, "mii[%d,%s]: carrier-detect no: SIOCGMIIREG failed: %s", ifindex, ifname, strerror (errno));
+		return FALSE;
 	}
 
-out:
-	close (fd);
-	nm_log_dbg (LOGD_PLATFORM, "mii: MII %s supported (%s)", supports_mii ? "is" : "not", ifname);
-	return supports_mii;
+	nm_log_trace (LOGD_PLATFORM, "mii[%d,%s]: carrier-detect yes: SIOCGMIIREG result 0x%X", ifindex, ifname, mii->val_out);
+	return TRUE;
 }
 
 /******************************************************************
@@ -486,22 +538,6 @@ out:
  * utils
  *****************************************************************************/
 
-gboolean
-nmp_utils_device_exists (const char *name)
-{
-#define SYS_CLASS_NET "/sys/class/net/"
-	char sysdir[NM_STRLEN (SYS_CLASS_NET) + IFNAMSIZ];
-
-	if (   !name
-	    || strlen (name) >= IFNAMSIZ
-	    || !nm_utils_is_valid_path_component (name))
-		g_return_val_if_reached (FALSE);
-
-	memcpy (sysdir, SYS_CLASS_NET, NM_STRLEN (SYS_CLASS_NET));
-	nm_utils_ifname_cpy (&sysdir[NM_STRLEN (SYS_CLASS_NET)], name);
-	return g_file_test (sysdir, G_FILE_TEST_EXISTS);
-}
-
 NMIPConfigSource
 nmp_utils_ip_config_source_from_rtprot (guint8 rtprot)
 {
@@ -623,3 +659,83 @@ nmp_utils_ip_config_source_to_string (NMIPConfigSource source, char *buf, gsize
 	return buf;
 }
 
+/**
+ * nmp_utils_sysctl_open_netdir:
+ * @ifindex: the ifindex for which to open "/sys/class/net/%s"
+ * @ifname_guess: (allow-none): optional argument, if present used as initial
+ *   guess as the current name for @ifindex. If guessed right,
+ *   it saves an addtional if_indextoname() call.
+ * @out_ifname: (allow-none): if present, must be at least IFNAMSIZ
+ *   characters. On success, this will contain the actual ifname
+ *   found while opening the directory.
+ *
+ * Returns: a negative value on failure, on success returns the open fd
+ *   to the "/sys/class/net/%s" directory for @ifindex.
+ */
+int
+nmp_utils_sysctl_open_netdir (int ifindex,
+                              const char *ifname_guess,
+                              char *out_ifname)
+{
+	#define SYS_CLASS_NET "/sys/class/net/"
+	const char *ifname = ifname_guess;
+	char ifname_buf_last_try[IFNAMSIZ];
+	char ifname_buf[IFNAMSIZ];
+	guint try_count = 0;
+	char sysdir[NM_STRLEN (SYS_CLASS_NET) + IFNAMSIZ] = SYS_CLASS_NET;
+	char fd_buf[256];
+	ssize_t nn;
+
+	g_return_val_if_fail (ifindex >= 0, -1);
+
+	ifname_buf_last_try[0] = '\0';
+
+	for (try_count = 0; try_count < 10; try_count++, ifname = NULL) {
+		nm_auto_close int fd_dir = -1;
+		nm_auto_close int fd_ifindex = -1;
+		int fd;
+
+		if (!ifname) {
+			ifname = if_indextoname (ifindex, ifname_buf);
+			if (!ifname)
+				return -1;
+		}
+
+		nm_assert (nm_utils_iface_valid_name (ifname));
+
+		if (g_strlcpy (&sysdir[NM_STRLEN (SYS_CLASS_NET)], ifname, IFNAMSIZ) >= IFNAMSIZ)
+			g_return_val_if_reached (-1);
+
+		/* we only retry, if the name changed since previous attempt.
+		 * Hence, it is extremely unlikely that this loop runes until the
+		 * end of the @try_count. */
+		if (nm_streq (ifname, ifname_buf_last_try))
+			return -1;
+		strcpy (ifname_buf_last_try, ifname);
+
+		fd_dir = open (sysdir, O_DIRECTORY | O_CLOEXEC);
+		if (fd_dir < 0)
+			continue;
+
+		fd_ifindex = openat (fd_dir, "ifindex", O_CLOEXEC);
+		if (fd_ifindex < 0)
+			continue;
+
+		nn = nm_utils_fd_read_loop (fd_ifindex, fd_buf, sizeof (fd_buf) - 2, FALSE);
+		if (nn <= 0)
+			continue;
+		fd_buf[nn] = '\0';
+
+		if (ifindex != _nm_utils_ascii_str_to_int64 (fd_buf, 10, 1, G_MAXINT, -1))
+			continue;
+
+		if (out_ifname)
+			strcpy (out_ifname, ifname);
+
+		fd = fd_dir;
+		fd_dir = -1;
+		return fd;
+	}
+
+	return -1;
+}
diff --git a/src/platform/nm-platform-utils.h b/src/platform/nm-platform-utils.h
index 4b4868c1e8..ea9607e6a3 100644
--- a/src/platform/nm-platform-utils.h
+++ b/src/platform/nm-platform-utils.h
@@ -27,38 +27,55 @@
 #include "nm-setting-wired.h"
 
 
-const char *nmp_utils_ethtool_get_driver (const char *ifname);
-gboolean nmp_utils_ethtool_supports_carrier_detect (const char *ifname);
-gboolean nmp_utils_ethtool_supports_vlans (const char *ifname);
-int nmp_utils_ethtool_get_peer_ifindex (const char *ifname);
-gboolean nmp_utils_ethtool_get_wake_on_lan (const char *ifname);
-gboolean nmp_utils_ethtool_set_wake_on_lan (const char *ifname, NMSettingWiredWakeOnLan wol,
+const char *nmp_utils_ethtool_get_driver (int ifindex);
+gboolean nmp_utils_ethtool_supports_carrier_detect (int ifindex);
+gboolean nmp_utils_ethtool_supports_vlans (int ifindex);
+int nmp_utils_ethtool_get_peer_ifindex (int ifindex);
+gboolean nmp_utils_ethtool_get_wake_on_lan (int ifindex);
+gboolean nmp_utils_ethtool_set_wake_on_lan (int ifindex, NMSettingWiredWakeOnLan wol,
                                             const char *wol_password);
 
-gboolean nmp_utils_ethtool_get_link_settings (const char *ifname, gboolean *out_autoneg, guint32 *out_speed, NMPlatformLinkDuplexType *out_duplex);
-gboolean nmp_utils_ethtool_set_link_settings (const char *ifname, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex);
+gboolean nmp_utils_ethtool_get_link_settings (int ifindex, gboolean *out_autoneg, guint32 *out_speed, NMPlatformLinkDuplexType *out_duplex);
+gboolean nmp_utils_ethtool_set_link_settings (int ifindex, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex);
 
-gboolean nmp_utils_ethtool_get_driver_info (const char *ifname,
-                                            char **out_driver_name,
-                                            char **out_driver_version,
-                                            char **out_fw_version);
+typedef struct {
+	/* We don't want to include <linux/ethtool.h> in header files,
+	 * thus create a ABI compatible version of struct ethtool_drvinfo.*/
+	guint32 _private_cmd;
+	char    driver[32];
+	char    version[32];
+	char    fw_version[32];
+	char    _private_bus_info[32];
+	char    _private_erom_version[32];
+	char    _private_reserved2[12];
+	guint32 _private_n_priv_flags;
+	guint32 _private_n_stats;
+	guint32 _private_testinfo_len;
+	guint32 _private_eedump_len;
+	guint32 _private_regdump_len;
+} NMPUtilsEthtoolDriverInfo;
 
-gboolean  nmp_utils_ethtool_get_permanent_address (const char *ifname,
+gboolean nmp_utils_ethtool_get_driver_info (int ifindex,
+                                            NMPUtilsEthtoolDriverInfo *data);
+
+gboolean  nmp_utils_ethtool_get_permanent_address (int ifindex,
                                                    guint8 *buf,
                                                    size_t *length);
 
 
-gboolean nmp_utils_mii_supports_carrier_detect (const char *ifname);
+gboolean nmp_utils_mii_supports_carrier_detect (int ifindex);
 
 
 const char *nmp_utils_udev_get_driver (GUdevDevice *device);
 
-gboolean nmp_utils_device_exists (const char *name);
-
 NMIPConfigSource nmp_utils_ip_config_source_from_rtprot (guint8 rtprot) _nm_const;
 guint8           nmp_utils_ip_config_source_coerce_to_rtprot   (NMIPConfigSource source) _nm_const;
 NMIPConfigSource nmp_utils_ip_config_source_coerce_from_rtprot (NMIPConfigSource source) _nm_const;
 NMIPConfigSource nmp_utils_ip_config_source_round_trip_rtprot  (NMIPConfigSource source) _nm_const;
 const char *     nmp_utils_ip_config_source_to_string (NMIPConfigSource source, char *buf, gsize len);
 
+int nmp_utils_sysctl_open_netdir (int ifindex,
+                                  const char *ifname_guess,
+                                  char *out_ifname);
+
 #endif /* __NM_PLATFORM_UTILS_H__ */
diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index af574a355c..d0b65adf08 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -266,8 +266,39 @@ nm_platform_process_events (NMPlatform *self)
 /*****************************************************************************/
 
 /**
+ * nm_platform_sysctl_open_netdir:
+ * @self: platform instance
+ * @ifindex: the ifindex for which to open /sys/class/net/%s
+ * @out_ifname: optional output argument of the found ifname.
+ *
+ * Wraps nmp_utils_sysctl_open_netdir() by first changing into the right
+ * network-namespace.
+ *
+ * Returns: on success, the open file descriptor to the /sys/class/net/%s
+ *   directory.
+ */
+int
+nm_platform_sysctl_open_netdir (NMPlatform *self, int ifindex, char *out_ifname)
+{
+	const char*ifname_guess;
+	_CHECK_SELF_NETNS (self, klass, netns, -1);
+
+	g_return_val_if_fail (ifindex > 0, -1);
+
+	/* we don't have an @ifname_guess argument to make the API nicer.
+	 * But still do a cache-lookup first. Chances are good that we have
+	 * the right ifname cached and save if_indextoname() */
+	ifname_guess = nm_platform_link_get_name (self, ifindex);
+
+	return nmp_utils_sysctl_open_netdir (ifindex, ifname_guess, out_ifname);
+}
+
+/**
  * nm_platform_sysctl_set:
  * @self: platform instance
+ * @pathid: if @dirfd is present, this must be the full path that is looked up.
+ *   It is required for logging.
+ * @dirfd: optional file descriptor for parent directory for openat()
  * @path: Absolute option path
  * @value: Value to write
  *
@@ -278,14 +309,14 @@ nm_platform_process_events (NMPlatform *self)
  * Returns: %TRUE on success.
  */
 gboolean
-nm_platform_sysctl_set (NMPlatform *self, const char *path, const char *value)
+nm_platform_sysctl_set (NMPlatform *self, const char *pathid, int dirfd, const char *path, const char *value)
 {
 	_CHECK_SELF (self, klass, FALSE);
 
 	g_return_val_if_fail (path, FALSE);
 	g_return_val_if_fail (value, FALSE);
 
-	return klass->sysctl_set (self, path, value);
+	return klass->sysctl_set (self, pathid, dirfd, path, value);
 }
 
 gboolean
@@ -305,7 +336,7 @@ nm_platform_sysctl_set_ip6_hop_limit_safe (NMPlatform *self, const char *iface,
 		return FALSE;
 
 	path = nm_utils_ip6_property_path (iface, "hop_limit");
-	cur = nm_platform_sysctl_get_int_checked (self, path, 10, 1, G_MAXINT32, -1);
+	cur = nm_platform_sysctl_get_int_checked (self, NMP_SYSCTL_PATHID_ABSOLUTE (path), 10, 1, G_MAXINT32, -1);
 
 	/* only allow increasing the hop-limit to avoid DOS by an attacker
 	 * setting a low hop-limit (CVE-2015-2924, rh#1209902) */
@@ -316,7 +347,7 @@ nm_platform_sysctl_set_ip6_hop_limit_safe (NMPlatform *self, const char *iface,
 		char svalue[20];
 
 		sprintf (svalue, "%d", value);
-		nm_platform_sysctl_set (self, path, svalue);
+		nm_platform_sysctl_set (self, NMP_SYSCTL_PATHID_ABSOLUTE (path), svalue);
 	}
 
 	return TRUE;
@@ -325,23 +356,29 @@ nm_platform_sysctl_set_ip6_hop_limit_safe (NMPlatform *self, const char *iface,
 /**
  * nm_platform_sysctl_get:
  * @self: platform instance
+ * @dirfd: if non-negative, used to lookup the path via openat().
+ * @pathid: if @dirfd is present, this must be the full path that is looked up.
+ *   It is required for logging.
  * @path: Absolute path to sysctl
  *
  * Returns: (transfer full): Contents of the virtual sysctl file.
  */
 char *
-nm_platform_sysctl_get (NMPlatform *self, const char *path)
+nm_platform_sysctl_get (NMPlatform *self, const char *pathid, int dirfd, const char *path)
 {
 	_CHECK_SELF (self, klass, NULL);
 
 	g_return_val_if_fail (path, NULL);
 
-	return klass->sysctl_get (self, path);
+	return klass->sysctl_get (self, pathid, dirfd, path);
 }
 
 /**
  * nm_platform_sysctl_get_int32:
  * @self: platform instance
+ * @pathid: if @dirfd is present, this must be the full path that is looked up.
+ *   It is required for logging.
+ * @dirfd: if non-negative, used to lookup the path via openat().
  * @path: Absolute path to sysctl
  * @fallback: default value, if the content of path could not be read
  * as decimal integer.
@@ -351,14 +388,17 @@ nm_platform_sysctl_get (NMPlatform *self, const char *path)
  * value, on success %errno will be set to zero.
  */
 gint32
-nm_platform_sysctl_get_int32 (NMPlatform *self, const char *path, gint32 fallback)
+nm_platform_sysctl_get_int32 (NMPlatform *self, const char *pathid, int dirfd, const char *path, gint32 fallback)
 {
-	return nm_platform_sysctl_get_int_checked (self, path, 10, G_MININT32, G_MAXINT32, fallback);
+	return nm_platform_sysctl_get_int_checked (self, pathid, dirfd, path, 10, G_MININT32, G_MAXINT32, fallback);
 }
 
 /**
  * nm_platform_sysctl_get_int_checked:
  * @self: platform instance
+ * @pathid: if @dirfd is present, this must be the full path that is looked up.
+ *   It is required for logging.
+ * @dirfd: if non-negative, used to lookup the path via openat().
  * @path: Absolute path to sysctl
  * @base: base of numeric conversion
  * @min: minimal value that is still valid
@@ -373,7 +413,7 @@ nm_platform_sysctl_get_int32 (NMPlatform *self, const char *path, gint32 fallbac
  * (inclusive) or @fallback.
  */
 gint64
-nm_platform_sysctl_get_int_checked (NMPlatform *self, const char *path, guint base, gint64 min, gint64 max, gint64 fallback)
+nm_platform_sysctl_get_int_checked (NMPlatform *self, const char *pathid, int dirfd, const char *path, guint base, gint64 min, gint64 max, gint64 fallback)
 {
 	char *value = NULL;
 	gint32 ret;
@@ -383,7 +423,7 @@ nm_platform_sysctl_get_int_checked (NMPlatform *self, const char *path, guint ba
 	g_return_val_if_fail (path, fallback);
 
 	if (path)
-		value = nm_platform_sysctl_get (self, path);
+		value = nm_platform_sysctl_get (self, pathid, dirfd, path);
 
 	if (!value) {
 		errno = EINVAL;
@@ -1668,34 +1708,44 @@ nm_platform_link_tun_add (NMPlatform *self,
 
 /*****************************************************************************/
 
-static char *
-link_option_path (NMPlatform *self, int master, const char *category, const char *option)
+static gboolean
+link_set_option (NMPlatform *self, int ifindex, const char *category, const char *option, const char *value)
 {
-	const char *name = nm_platform_link_get_name (self, master);
-
-	if (!name || !category || !option)
-		return NULL;
+	nm_auto_close int dirfd = -1;
+	char ifname_verified[IFNAMSIZ];
+	const char *path;
 
-	return g_strdup_printf ("/sys/class/net/%s/%s/%s",
-	                        NM_ASSERT_VALID_PATH_COMPONENT (name),
-	                        NM_ASSERT_VALID_PATH_COMPONENT (category),
-	                        NM_ASSERT_VALID_PATH_COMPONENT (option));
-}
+	if (!category || !option)
+		return FALSE;
 
-static gboolean
-link_set_option (NMPlatform *self, int master, const char *category, const char *option, const char *value)
-{
-	gs_free char *path = link_option_path (self, master, category, option);
+	dirfd = nm_platform_sysctl_open_netdir (self, ifindex, ifname_verified);
+	if (dirfd < 0)
+		return FALSE;
 
-	return path && nm_platform_sysctl_set (self, path, value);
+	path = nm_sprintf_bufa (strlen (category) + strlen (option) + 2,
+	                        "%s/%s",
+	                        category, option);
+	return nm_platform_sysctl_set (self, NMP_SYSCTL_PATHID_NETDIR_unsafe (dirfd, ifname_verified, path), value);
 }
 
 static char *
-link_get_option (NMPlatform *self, int master, const char *category, const char *option)
+link_get_option (NMPlatform *self, int ifindex, const char *category, const char *option)
 {
-	gs_free char *path = link_option_path (self, master, category, option);
+	nm_auto_close int dirfd = -1;
+	char ifname_verified[IFNAMSIZ];
+	const char *path;
+
+	if (!category || !option)
+		return NULL;
+
+	dirfd = nm_platform_sysctl_open_netdir (self, ifindex, ifname_verified);
+	if (dirfd < 0)
+		return NULL;
 
-	return path ? nm_platform_sysctl_get (self, path) : NULL;
+	path = nm_sprintf_bufa (strlen (category) + strlen (option) + 2,
+	                        "%s/%s",
+	                        category, option);
+	return nm_platform_sysctl_get (self, NMP_SYSCTL_PATHID_NETDIR_unsafe (dirfd, ifname_verified, path));
 }
 
 static const char *
@@ -1973,10 +2023,11 @@ nm_platform_link_infiniband_get_properties (NMPlatform *self,
                                             int *out_p_key,
                                             const char **out_mode)
 {
+	nm_auto_close int dirfd = -1;
+	char ifname_verified[IFNAMSIZ];
 	const NMPlatformLnkInfiniband *plnk;
 	const NMPlatformLink *plink;
-	const char *iface;
-	char *path, *contents;
+	char *contents;
 	const char *mode;
 	int p_key = 0;
 
@@ -2000,15 +2051,13 @@ nm_platform_link_infiniband_get_properties (NMPlatform *self,
 	/* Could not get the link information via netlink. To support older kernels,
 	 * fallback to reading sysfs. */
 
-	iface = NM_ASSERT_VALID_PATH_COMPONENT (plink->name);
+	dirfd = nm_platform_sysctl_open_netdir (self, ifindex, ifname_verified);
+	if (dirfd < 0)
+		return FALSE;
 
-	/* Fall back to reading sysfs */
-	path = g_strdup_printf ("/sys/class/net/%s/mode", iface);
-	contents = nm_platform_sysctl_get (self, path);
-	g_free (path);
+	contents = nm_platform_sysctl_get (self, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_verified, "mode"));
 	if (!contents)
 		return FALSE;
-
 	if (strstr (contents, "datagram"))
 		mode = "datagram";
 	else if (strstr (contents, "connected"))
@@ -2017,13 +2066,7 @@ nm_platform_link_infiniband_get_properties (NMPlatform *self,
 		mode = NULL;
 	g_free (contents);
 
-	path = g_strdup_printf ("/sys/class/net/%s/pkey", iface);
-	contents = nm_platform_sysctl_get (self, path);
-	g_free (path);
-	if (!contents)
-		return FALSE;
-	p_key = (int) _nm_utils_ascii_str_to_int64 (contents, 16, 0, 0xFFFF, -1);
-	g_free (contents);
+	p_key = nm_platform_sysctl_get_int_checked (self, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname_verified, "pkey"), 16, 0, 0xFFFF, -1);
 	if (p_key < 0)
 		return FALSE;
 
@@ -2216,7 +2259,7 @@ nm_platform_link_veth_get_properties (NMPlatform *self, int ifindex, int *out_pe
 
 		if (!nm_platform_netns_push (self, &netns))
 			return FALSE;
-		peer_ifindex = nmp_utils_ethtool_get_peer_ifindex (plink->name);
+		peer_ifindex = nmp_utils_ethtool_get_peer_ifindex (plink->ifindex);
 		if (peer_ifindex <= 0)
 			return FALSE;
 
@@ -2226,57 +2269,53 @@ nm_platform_link_veth_get_properties (NMPlatform *self, int ifindex, int *out_pe
 }
 
 gboolean
-nm_platform_link_tun_get_properties_ifname (NMPlatform *self, const char *ifname, NMPlatformTunProperties *props)
+nm_platform_link_tun_get_properties (NMPlatform *self, int ifindex, const char *ifname_guess, NMPlatformTunProperties *props)
 {
-	char path[256];
-	char *val;
+	nm_auto_close int dirfd = -1;
+	const char *ifname;
+	char ifname_verified[IFNAMSIZ];
+	gint64 flags;
 	gboolean success = TRUE;
-
 	_CHECK_SELF (self, klass, FALSE);
 
+	g_return_val_if_fail (ifindex > 0, FALSE);
 	g_return_val_if_fail (props, FALSE);
 
+	/* ifname_guess is an optional argument to find a guess for the ifname corresponding to
+	 * ifindex. */
+	if (!ifname_guess) {
+		/* if NULL, obtain the guess from the platform cache. */
+		ifname = nm_platform_link_get_name (self, ifindex);
+	} else if (!ifname_guess[0]) {
+		/* if empty, don't use a guess. That means to use if_indextoname(). */
+		ifname = NULL;
+	} else
+		ifname = ifname_guess;
+
 	memset (props, 0, sizeof (*props));
 	props->owner = -1;
 	props->group = -1;
 
-	if (!ifname || !nm_utils_iface_valid_name (ifname))
+	dirfd = nm_platform_sysctl_open_netdir (self, ifindex, ifname_verified);
+	if (dirfd < 0)
 		return FALSE;
 
-	nm_sprintf_buf (path, "/sys/class/net/%s/owner", ifname);
-	val = nm_platform_sysctl_get (self, path);
-	if (val) {
-		props->owner = _nm_utils_ascii_str_to_int64 (val, 10, -1, G_MAXINT64, -1);
-		if (errno)
-			success = FALSE;
-		g_free (val);
-	} else
+	ifname = ifname_verified;
+
+	props->owner = nm_platform_sysctl_get_int_checked (self, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname, "owner"), 10, -1, G_MAXINT64, -1);
+	if (errno)
 		success = FALSE;
 
-	nm_sprintf_buf (path, "/sys/class/net/%s/group", ifname);
-	val = nm_platform_sysctl_get (self, path);
-	if (val) {
-		props->group = _nm_utils_ascii_str_to_int64 (val, 10, -1, G_MAXINT64, -1);
-		if (errno)
-			success = FALSE;
-		g_free (val);
-	} else
+	props->group = nm_platform_sysctl_get_int_checked (self, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname, "group"), 10, -1, G_MAXINT64, -1);
+	if (errno)
 		success = FALSE;
 
-	nm_sprintf_buf (path, "/sys/class/net/%s/tun_flags", ifname);
-	val = nm_platform_sysctl_get (self, path);
-	if (val) {
-		gint64 flags;
-
-		flags = _nm_utils_ascii_str_to_int64 (val, 16, 0, G_MAXINT64, 0);
-		if (!errno) {
-			props->mode = ((flags & (IFF_TUN | IFF_TAP)) == IFF_TUN) ? "tun" : "tap";
-			props->no_pi = !!(flags & IFF_NO_PI);
-			props->vnet_hdr = !!(flags & IFF_VNET_HDR);
-			props->multi_queue = !!(flags & NM_IFF_MULTI_QUEUE);
-		} else
-			success = FALSE;
-		g_free (val);
+	flags = nm_platform_sysctl_get_int_checked (self, NMP_SYSCTL_PATHID_NETDIR (dirfd, ifname, "tun_flags"), 16, 0, G_MAXINT64, -1);
+	if (flags >= 0) {
+		props->mode = ((flags & (IFF_TUN | IFF_TAP)) == IFF_TUN) ? "tun" : "tap";
+		props->no_pi = !!(flags & IFF_NO_PI);
+		props->vnet_hdr = !!(flags & IFF_VNET_HDR);
+		props->multi_queue = !!(flags & NM_IFF_MULTI_QUEUE);
 	} else
 		success = FALSE;
 
@@ -2284,17 +2323,6 @@ nm_platform_link_tun_get_properties_ifname (NMPlatform *self, const char *ifname
 }
 
 gboolean
-nm_platform_link_tun_get_properties (NMPlatform *self, int ifindex, NMPlatformTunProperties *props)
-{
-	_CHECK_SELF (self, klass, FALSE);
-
-	g_return_val_if_fail (ifindex > 0, FALSE);
-	g_return_val_if_fail (props != NULL, FALSE);
-
-	return nm_platform_link_tun_get_properties_ifname (self, nm_platform_link_get_name (self, ifindex), props);
-}
-
-gboolean
 nm_platform_wifi_get_capabilities (NMPlatform *self, int ifindex, NMDeviceWifiCapabilities *caps)
 {
 	_CHECK_SELF (self, klass, FALSE);
@@ -2479,27 +2507,33 @@ _to_string_ifa_flags (guint32 ifa_flags, char *buf, gsize size)
 /*****************************************************************************/
 
 gboolean
-nm_platform_ethtool_set_wake_on_lan (NMPlatform *self, const char *ifname, NMSettingWiredWakeOnLan wol, const char *wol_password)
+nm_platform_ethtool_set_wake_on_lan (NMPlatform *self, int ifindex, NMSettingWiredWakeOnLan wol, const char *wol_password)
 {
 	_CHECK_SELF_NETNS (self, klass, netns, FALSE);
 
-	return nmp_utils_ethtool_set_wake_on_lan (ifname, wol, wol_password);
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
+	return nmp_utils_ethtool_set_wake_on_lan (ifindex, wol, wol_password);
 }
 
 gboolean
-nm_platform_ethtool_set_link_settings (NMPlatform *self, const char *ifname, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex)
+nm_platform_ethtool_set_link_settings (NMPlatform *self, int ifindex, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex)
 {
 	_CHECK_SELF_NETNS (self, klass, netns, FALSE);
 
-	return nmp_utils_ethtool_set_link_settings (ifname, autoneg, speed, duplex);
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
+	return nmp_utils_ethtool_set_link_settings (ifindex, autoneg, speed, duplex);
 }
 
 gboolean
-nm_platform_ethtool_get_link_settings (NMPlatform *self, const char *ifname, gboolean *out_autoneg, guint32 *out_speed,  NMPlatformLinkDuplexType *out_duplex)
+nm_platform_ethtool_get_link_settings (NMPlatform *self, int ifindex, gboolean *out_autoneg, guint32 *out_speed,  NMPlatformLinkDuplexType *out_duplex)
 {
 	_CHECK_SELF_NETNS (self, klass, netns, FALSE);
 
-	return nmp_utils_ethtool_get_link_settings (ifname, out_autoneg, out_speed, out_duplex);
+	g_return_val_if_fail (ifindex > 0, FALSE);
+
+	return nmp_utils_ethtool_get_link_settings (ifindex, out_autoneg, out_speed, out_duplex);
 }
 
 /*****************************************************************************/
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index a546e4eaec..55d7a6f20e 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -500,8 +500,8 @@ struct _NMPlatform {
 typedef struct {
 	GObjectClass parent;
 
-	gboolean (*sysctl_set) (NMPlatform *, const char *path, const char *value);
-	char * (*sysctl_get) (NMPlatform *, const char *path);
+	gboolean (*sysctl_set) (NMPlatform *, const char *pathid, int dirfd, const char *path, const char *value);
+	char * (*sysctl_get) (NMPlatform *, const char *pathid, int dirfd, const char *path);
 
 	const NMPlatformLink *(*link_get) (NMPlatform *platform, int ifindex);
 	const NMPlatformLink *(*link_get_by_ifname) (NMPlatform *platform, const char *ifname);
@@ -717,10 +717,24 @@ const char *nm_link_type_to_string (NMLinkType link_type);
 const char *_nm_platform_error_to_string (NMPlatformError error);
 #define nm_platform_error_to_string(error) NM_UTILS_LOOKUP_STR (_nm_platform_error_to_string, error)
 
-gboolean nm_platform_sysctl_set (NMPlatform *self, const char *path, const char *value);
-char *nm_platform_sysctl_get (NMPlatform *self, const char *path);
-gint32 nm_platform_sysctl_get_int32 (NMPlatform *self, const char *path, gint32 fallback);
-gint64 nm_platform_sysctl_get_int_checked (NMPlatform *self, const char *path, guint base, gint64 min, gint64 max, gint64 fallback);
+#define NMP_SYSCTL_PATHID_ABSOLUTE(path) \
+	((const char *) NULL), -1, (path)
+
+#define NMP_SYSCTL_PATHID_NETDIR_unsafe(dirfd, ifname, path) \
+	nm_sprintf_bufa (NM_STRLEN ("net:/sys/class/net//\0") + IFNAMSIZ + strlen (path), \
+	                 "net:/sys/class/net/%s/%s", (ifname), (path)), \
+	(dirfd), (path)
+
+#define NMP_SYSCTL_PATHID_NETDIR(dirfd, ifname, path) \
+	nm_sprintf_bufa (NM_STRLEN ("net:/sys/class/net//"path"/\0") + IFNAMSIZ, \
+	                 "net:/sys/class/net/%s/%s", (ifname), path), \
+	(dirfd), (""path"")
+
+int nm_platform_sysctl_open_netdir (NMPlatform *self, int ifindex, char *out_ifname);
+gboolean nm_platform_sysctl_set (NMPlatform *self, const char *pathid, int dirfd, const char *path, const char *value);
+char *nm_platform_sysctl_get (NMPlatform *self, const char *pathid, int dirfd, const char *path);
+gint32 nm_platform_sysctl_get_int32 (NMPlatform *self, const char *pathid, int dirfd, const char *path, gint32 fallback);
+gint64 nm_platform_sysctl_get_int_checked (NMPlatform *self, const char *pathid, int dirfd, const char *path, guint base, gint64 min, gint64 max, gint64 fallback);
 
 gboolean nm_platform_sysctl_set_ip6_hop_limit_safe (NMPlatform *self, const char *iface, int value);
 
@@ -851,9 +865,7 @@ NMPlatformError nm_platform_link_infiniband_delete (NMPlatform *self,
 gboolean nm_platform_link_infiniband_get_properties (NMPlatform *self, int ifindex, int *parent, int *p_key, const char **mode);
 
 gboolean nm_platform_link_veth_get_properties   (NMPlatform *self, int ifindex, int *out_peer_ifindex);
-gboolean nm_platform_link_tun_get_properties    (NMPlatform *self, int ifindex, NMPlatformTunProperties *properties);
-
-gboolean nm_platform_link_tun_get_properties_ifname (NMPlatform *platform, const char *ifname, NMPlatformTunProperties *props);
+gboolean nm_platform_link_tun_get_properties    (NMPlatform *self, int ifindex, const char *ifname_guess, NMPlatformTunProperties *properties);
 
 gboolean    nm_platform_wifi_get_capabilities (NMPlatform *self, int ifindex, NMDeviceWifiCapabilities *caps);
 gboolean    nm_platform_wifi_get_bssid        (NMPlatform *self, int ifindex, guint8 *bssid);
@@ -980,8 +992,8 @@ const char *nm_platform_route_scope2str (int scope, char *buf, gsize len);
 
 int nm_platform_ip_address_cmp_expiry (const NMPlatformIPAddress *a, const NMPlatformIPAddress *b);
 
-gboolean nm_platform_ethtool_set_wake_on_lan (NMPlatform *self, const char *ifname, NMSettingWiredWakeOnLan wol, const char *wol_password);
-gboolean nm_platform_ethtool_set_link_settings (NMPlatform *self, const char *ifname, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex);
-gboolean nm_platform_ethtool_get_link_settings (NMPlatform *self, const char *ifname, gboolean *out_autoneg, guint32 *out_speed, NMPlatformLinkDuplexType *out_duplex);
+gboolean nm_platform_ethtool_set_wake_on_lan (NMPlatform *self, int ifindex, NMSettingWiredWakeOnLan wol, const char *wol_password);
+gboolean nm_platform_ethtool_set_link_settings (NMPlatform *self, int ifindex, gboolean autoneg, guint32 speed, NMPlatformLinkDuplexType duplex);
+gboolean nm_platform_ethtool_get_link_settings (NMPlatform *self, int ifindex, gboolean *out_autoneg, guint32 *out_speed, NMPlatformLinkDuplexType *out_duplex);
 
 #endif /* __NETWORKMANAGER_PLATFORM_H__ */
diff --git a/src/platform/nmp-netns.c b/src/platform/nmp-netns.c
index f3704f0313..232c6efc9e 100644
--- a/src/platform/nmp-netns.c
+++ b/src/platform/nmp-netns.c
@@ -284,7 +284,7 @@ _netns_new (GError **error)
 	int fd_net, fd_mnt;
 	int errsv;
 
-	fd_net = open (PROC_SELF_NS_NET, O_RDONLY);
+	fd_net = open (PROC_SELF_NS_NET, O_RDONLY | O_CLOEXEC);
 	if (fd_net == -1) {
 		errsv = errno;
 		g_set_error (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
@@ -293,7 +293,7 @@ _netns_new (GError **error)
 		return NULL;
 	}
 
-	fd_mnt = open (PROC_SELF_NS_MNT, O_RDONLY);
+	fd_mnt = open (PROC_SELF_NS_MNT, O_RDONLY | O_CLOEXEC);
 	if (fd_mnt == -1) {
 		errsv = errno;
 		g_set_error (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
@@ -631,7 +631,7 @@ nmp_netns_bind_to_path (NMPNetns *self, const char *filename, int *out_fd)
 	}
 
 	if (out_fd) {
-		if ((fd = open (filename, O_RDONLY)) == -1) {
+		if ((fd = open (filename, O_RDONLY | O_CLOEXEC)) == -1) {
 			errsv = errno;
 			_LOGE (self, "bind: failed to open %s: %s", filename, g_strerror (errsv));
 			umount2 (filename, MNT_DETACH);
diff --git a/src/platform/nmp-netns.h b/src/platform/nmp-netns.h
index eb33f2ed64..56c1e7e83a 100644
--- a/src/platform/nmp-netns.h
+++ b/src/platform/nmp-netns.h
@@ -53,8 +53,12 @@ int nmp_netns_get_fd_mnt (NMPNetns *self);
 static inline void
 _nm_auto_pop_netns (NMPNetns **p)
 {
-	if (*p)
+	if (*p) {
+		int errsv = errno;
+
 		nmp_netns_pop (*p);
+		errno = errsv;
+	}
 }
 
 #define nm_auto_pop_netns __attribute__((cleanup(_nm_auto_pop_netns)))
diff --git a/src/platform/nmp-object.c b/src/platform/nmp-object.c
index 936c41f270..c0380ec567 100644
--- a/src/platform/nmp-object.c
+++ b/src/platform/nmp-object.c
@@ -125,7 +125,7 @@ _vlan_xgress_qos_mappings_cpy (guint *dst_n_map,
 /*****************************************************************************/
 
 static const char *
-_link_get_driver (GUdevDevice *udev_device, const char *kind, const char *ifname)
+_link_get_driver (GUdevDevice *udev_device, const char *kind, int ifindex)
 {
 	const char *driver = NULL;
 
@@ -140,14 +140,12 @@ _link_get_driver (GUdevDevice *udev_device, const char *kind, const char *ifname
 	if (kind)
 		return kind;
 
-	if (ifname) {
-		char *d;
+	if (ifindex > 0) {
+		NMPUtilsEthtoolDriverInfo driver_info;
 
-		if (nmp_utils_ethtool_get_driver_info (ifname, &d, NULL, NULL)) {
-			driver = d && d[0] ? g_intern_string (d) : NULL;
-			g_free (d);
-			if (driver)
-				return driver;
+		if (nmp_utils_ethtool_get_driver_info (ifindex, &driver_info)) {
+			if (driver_info.driver[0])
+				return g_intern_string (driver_info.driver);
 		}
 	}
 
@@ -169,7 +167,7 @@ _nmp_object_fixup_link_udev_fields (NMPObject *obj, gboolean use_udev)
 	if (obj->_link.netlink.is_in_netlink) {
 		driver = _link_get_driver (obj->_link.udev.device,
 		                           obj->link.kind,
-		                           obj->link.name);
+		                           obj->link.ifindex);
 		if (obj->_link.udev.device)
 			initialized = TRUE;
 		else if (!use_udev) {
diff --git a/src/platform/tests/test-common.c b/src/platform/tests/test-common.c
index f23cec4606..89cbd188ed 100644
--- a/src/platform/tests/test-common.c
+++ b/src/platform/tests/test-common.c
@@ -1407,7 +1407,7 @@ nmtstp_namespace_create (int unshare_flags, GError **error)
 	int pipefd_p2c[2];
 	ssize_t r;
 
-	e = pipe (pipefd_c2p);
+	e = pipe2 (pipefd_c2p, O_CLOEXEC);
 	if (e != 0) {
 		errsv = errno;
 		g_set_error (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
@@ -1415,7 +1415,7 @@ nmtstp_namespace_create (int unshare_flags, GError **error)
 		return FALSE;
 	}
 
-	e = pipe (pipefd_p2c);
+	e = pipe2 (pipefd_p2c, O_CLOEXEC);
 	if (e != 0) {
 		errsv = errno;
 		g_set_error (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
@@ -1549,7 +1549,26 @@ nmtstp_namespace_get_fd_for_process (pid_t pid, const char *ns_name)
 
 	nm_sprintf_buf (p, "/proc/%lu/ns/%s", (long unsigned) pid, ns_name);
 
-	return open(p, O_RDONLY);
+	return open(p, O_RDONLY | O_CLOEXEC);
+}
+
+/*****************************************************************************/
+
+void
+nmtstp_netns_select_random (NMPlatform **platforms, gsize n_platforms, NMPNetns **netns)
+{
+	int i;
+
+	g_assert (platforms);
+	g_assert (n_platforms && n_platforms <= G_MAXINT32);
+	g_assert (netns && !*netns);
+	for (i = 0; i < n_platforms; i++)
+		g_assert (NM_IS_PLATFORM (platforms[i]));
+
+	i = nmtst_get_rand_int () % (n_platforms + 1);
+	if (i == 0)
+		return;
+	g_assert (nm_platform_netns_push (platforms[i - 1], netns));
 }
 
 /*****************************************************************************/
@@ -1573,21 +1592,21 @@ unshare_user (void)
 
 	/* Since Linux 3.19 we have to disable setgroups() in order to map users.
 	 * Just proceed if the file is not there. */
-	f = fopen ("/proc/self/setgroups", "w");
+	f = fopen ("/proc/self/setgroups", "we");
 	if (f) {
 		fprintf (f, "deny");
 		fclose (f);
 	}
 
 	/* Map current UID to root in NS to be created. */
-	f = fopen ("/proc/self/uid_map", "w");
+	f = fopen ("/proc/self/uid_map", "we");
 	if (!f)
 		return FALSE;
 	fprintf (f, "0 %d 1", uid);
 	fclose (f);
 
 	/* Map current GID to root in NS to be created. */
-	f = fopen ("/proc/self/gid_map", "w");
+	f = fopen ("/proc/self/gid_map", "we");
 	if (!f)
 		return FALSE;
 	fprintf (f, "0 %d 1", gid);
diff --git a/src/platform/tests/test-common.h b/src/platform/tests/test-common.h
index a9f4959091..48a41de63a 100644
--- a/src/platform/tests/test-common.h
+++ b/src/platform/tests/test-common.h
@@ -53,6 +53,10 @@ int nmtstp_namespace_get_fd_for_process (pid_t pid, const char *ns_name);
 
 /*****************************************************************************/
 
+void nmtstp_netns_select_random (NMPlatform **platforms, gsize n_platforms, NMPNetns **netns);
+
+/*****************************************************************************/
+
 typedef struct {
 	gulong handler_id;
 	const char *name;
diff --git a/src/platform/tests/test-link.c b/src/platform/tests/test-link.c
index e3b55e73c8..c2b3de1391 100644
--- a/src/platform/tests/test-link.c
+++ b/src/platform/tests/test-link.c
@@ -398,26 +398,28 @@ test_software (NMLinkType link_type, const char *link_typename)
 	accept_signal (link_changed);
 
 	/* Set master option */
-	switch (link_type) {
-	case NM_LINK_TYPE_BRIDGE:
-		if (nmtstp_is_sysfs_writable ()) {
-			g_assert (nm_platform_sysctl_master_set_option (NM_PLATFORM_GET, ifindex, "forward_delay", "628"));
-			value = nm_platform_sysctl_master_get_option (NM_PLATFORM_GET, ifindex, "forward_delay");
-			g_assert_cmpstr (value, ==, "628");
-			g_free (value);
-		}
-		break;
-	case NM_LINK_TYPE_BOND:
-		if (nmtstp_is_sysfs_writable ()) {
-			g_assert (nm_platform_sysctl_master_set_option (NM_PLATFORM_GET, ifindex, "mode", "active-backup"));
-			value = nm_platform_sysctl_master_get_option (NM_PLATFORM_GET, ifindex, "mode");
-			/* When reading back, the output looks slightly different. */
-			g_assert (g_str_has_prefix (value, "active-backup"));
-			g_free (value);
+	if (nmtstp_is_root_test ()) {
+		switch (link_type) {
+		case NM_LINK_TYPE_BRIDGE:
+			if (nmtstp_is_sysfs_writable ()) {
+				g_assert (nm_platform_sysctl_master_set_option (NM_PLATFORM_GET, ifindex, "forward_delay", "628"));
+				value = nm_platform_sysctl_master_get_option (NM_PLATFORM_GET, ifindex, "forward_delay");
+				g_assert_cmpstr (value, ==, "628");
+				g_free (value);
+			}
+			break;
+		case NM_LINK_TYPE_BOND:
+			if (nmtstp_is_sysfs_writable ()) {
+				g_assert (nm_platform_sysctl_master_set_option (NM_PLATFORM_GET, ifindex, "mode", "active-backup"));
+				value = nm_platform_sysctl_master_get_option (NM_PLATFORM_GET, ifindex, "mode");
+				/* When reading back, the output looks slightly different. */
+				g_assert (g_str_has_prefix (value, "active-backup"));
+				g_free (value);
+			}
+			break;
+		default:
+			break;
 		}
-		break;
-	default:
-		break;
 	}
 
 	/* Enslave and release */
@@ -1941,7 +1943,7 @@ _test_netns_check_skip (void)
 	G_STMT_START { \
 		gs_free char *_val = NULL; \
 		\
-		_val = nm_platform_sysctl_get (plat, path); \
+		_val = nm_platform_sysctl_get (plat, NMP_SYSCTL_PATHID_ABSOLUTE (path)); \
 		g_assert_cmpstr (_val, ==, value); \
 	} G_STMT_END
 
@@ -1954,6 +1956,7 @@ test_netns_general (gpointer fixture, gconstpointer test_data)
 	char sbuf[100];
 	int i, j, k;
 	gboolean ethtool_support;
+	NMPUtilsEthtoolDriverInfo driver_info;
 
 	if (_test_netns_check_skip ())
 		return;
@@ -2013,7 +2016,7 @@ test_netns_general (gpointer fixture, gconstpointer test_data)
 			else
 				path = "/proc/sys/net/ipv6/conf/dummy2b/disable_ipv6";
 		}
-		g_assert (nm_platform_sysctl_set (pl, path, nm_sprintf_buf (sbuf, "%d", j)));
+		g_assert (nm_platform_sysctl_set (pl, NMP_SYSCTL_PATHID_ABSOLUTE (path), nm_sprintf_buf (sbuf, "%d", j)));
 		_sysctl_assert_eq (pl, path, nm_sprintf_buf (sbuf, "%d", j));
 	}
 
@@ -2024,9 +2027,8 @@ test_netns_general (gpointer fixture, gconstpointer test_data)
 	 * skip asserts that are known to fail. */
 	ethtool_support = nmtstp_run_command ("ethtool -i dummy1_ > /dev/null") == 0;
 	if (ethtool_support) {
-		g_assert ( nmp_utils_ethtool_get_driver_info ("dummy1_", NULL, NULL, NULL));
-		g_assert ( nmp_utils_ethtool_get_driver_info ("dummy2a", NULL, NULL, NULL));
-		g_assert (!nmp_utils_ethtool_get_driver_info ("dummy2b", NULL, NULL, NULL));
+		g_assert (nmp_utils_ethtool_get_driver_info (nmtstp_link_get_typed (platform_1, 0, "dummy1_", NM_LINK_TYPE_DUMMY)->ifindex, &driver_info));
+		g_assert (nmp_utils_ethtool_get_driver_info (nmtstp_link_get_typed (platform_1, 0, "dummy2a", NM_LINK_TYPE_DUMMY)->ifindex, &driver_info));
 		g_assert_cmpint (nmtstp_run_command ("ethtool -i dummy1_ > /dev/null"), ==, 0);
 		g_assert_cmpint (nmtstp_run_command ("ethtool -i dummy2a > /dev/null"), ==, 0);
 		g_assert_cmpint (nmtstp_run_command ("ethtool -i dummy2b 2> /dev/null"), !=, 0);
@@ -2035,9 +2037,8 @@ test_netns_general (gpointer fixture, gconstpointer test_data)
 	g_assert (nm_platform_netns_push (platform_2, &netns_tmp));
 
 	if (ethtool_support) {
-		g_assert ( nmp_utils_ethtool_get_driver_info ("dummy1_", NULL, NULL, NULL));
-		g_assert (!nmp_utils_ethtool_get_driver_info ("dummy2a", NULL, NULL, NULL));
-		g_assert ( nmp_utils_ethtool_get_driver_info ("dummy2b", NULL, NULL, NULL));
+		g_assert (nmp_utils_ethtool_get_driver_info (nmtstp_link_get_typed (platform_2, 0, "dummy1_", NM_LINK_TYPE_DUMMY)->ifindex, &driver_info));
+		g_assert (nmp_utils_ethtool_get_driver_info (nmtstp_link_get_typed (platform_2, 0, "dummy2b", NM_LINK_TYPE_DUMMY)->ifindex, &driver_info));
 		g_assert_cmpint (nmtstp_run_command ("ethtool -i dummy1_ > /dev/null"), ==, 0);
 		g_assert_cmpint (nmtstp_run_command ("ethtool -i dummy2a 2> /dev/null"), !=, 0);
 		g_assert_cmpint (nmtstp_run_command ("ethtool -i dummy2b > /dev/null"), ==, 0);
@@ -2056,7 +2057,6 @@ test_netns_set_netns (gpointer fixture, gconstpointer test_data)
 	gs_unref_object NMPlatform *platform_1 = NULL;
 	gs_unref_object NMPlatform *platform_2 = NULL;
 	nm_auto_pop_netns NMPNetns *netns_pop = NULL;
-	int i;
 
 	if (_test_netns_check_skip ())
 		return;
@@ -2065,9 +2065,7 @@ test_netns_set_netns (gpointer fixture, gconstpointer test_data)
 	platforms[1] = platform_1 = _test_netns_create_platform ();
 	platforms[2] = platform_2 = _test_netns_create_platform ();
 
-	i = nmtst_get_rand_int () % 4;
-	if (i != 3)
-		g_assert (nm_platform_netns_push (platforms[i], &netns_pop));
+	nmtstp_netns_select_random (platforms, G_N_ELEMENTS (platforms), &netns_pop);
 
 #define LINK_MOVE_NAME "link-move"
 	g_assert (!nm_platform_link_get_by_ifname (platform_1, LINK_MOVE_NAME));
@@ -2187,7 +2185,7 @@ test_netns_push (gpointer fixture, gconstpointer test_data)
 
 		_ADD_DUMMY (pl[i].platform, pl[i].device_name);
 
-		g_assert (nm_platform_sysctl_set (pl[i].platform, pl[i].sysctl_path, pl[i].sysctl_value));
+		g_assert (nm_platform_sysctl_set (pl[i].platform, NMP_SYSCTL_PATHID_ABSOLUTE (pl[i].sysctl_path), pl[i].sysctl_value));
 
 		tmp = _get_current_namespace_id (CLONE_NEWNET);
 		g_ptr_array_add (device_names, tmp);
@@ -2294,9 +2292,7 @@ test_netns_bind_to_path (gpointer fixture, gconstpointer test_data)
 	platforms[1] = platform_1 = _test_netns_create_platform ();
 	platforms[2] = platform_2 = _test_netns_create_platform ();
 
-	i = nmtst_get_rand_int () % 4;
-	if (i != 3)
-		g_assert (nm_platform_netns_push (platforms[i], &netns_pop));
+	nmtstp_netns_select_random (platforms, G_N_ELEMENTS (platforms), &netns_pop);
 
 	g_assert_cmpint (mount ("tmpfs", P_VAR_RUN, "tmpfs", MS_NOATIME | MS_NODEV | MS_NOSUID, "mode=0755,size=32K"), ==, 0);
 	g_assert_cmpint (mkdir (P_VAR_RUN_NETNS, 755), ==, 0);
@@ -2325,6 +2321,173 @@ test_netns_bind_to_path (gpointer fixture, gconstpointer test_data)
 
 /*****************************************************************************/
 
+static void
+test_sysctl_rename (void)
+{
+	NMPlatform *const PL = NM_PLATFORM_GET;
+	const char *const IFNAME[3] = {
+		"nm-dummy-0",
+		"nm-dummy-1",
+		"nm-dummy-2",
+	};
+	int ifindex[G_N_ELEMENTS (IFNAME)] = { 0 };
+	nm_auto_close int dirfd = -1;
+	int i;
+	char ifname_buf[IFNAMSIZ];
+	char *s;
+	const NMPlatformLink *pllink;
+
+	ifindex[0] = nmtstp_link_dummy_add (PL, -1, IFNAME[0])->ifindex;
+	ifindex[1] = nmtstp_link_dummy_add (PL, -1, IFNAME[1])->ifindex;
+
+	s = (nmtst_get_rand_int () % 2) ? NULL : ifname_buf;
+
+	if (nmtst_get_rand_int () % 2) {
+		/* bring the platform cache out of sync */
+		nmtstp_run_command_check ("ip link set %s name %s", IFNAME[0], IFNAME[2]);
+		nm_platform_process_events (PL);
+		nmtstp_run_command_check ("ip link set %s name %s", IFNAME[2], IFNAME[0]);
+
+		pllink = nm_platform_link_get_by_ifname (PL, IFNAME[2]);
+		g_assert (pllink && pllink->ifindex == ifindex[0]);
+		pllink = nm_platform_link_get_by_ifname (PL, IFNAME[0]);
+		g_assert (!pllink);
+	}
+
+	/* open dirfd for IFNAME[0] */
+	i = nmtst_get_rand_int () % (2 + G_N_ELEMENTS (IFNAME));
+	if (i == 0) {
+		dirfd = nm_platform_sysctl_open_netdir (PL,
+		                                        ifindex[0],
+		                                        s);
+	} else {
+		const char *ifname_guess;
+
+		/* provide a wrong or no guess. */
+		ifname_guess = i == 1 ? NULL : IFNAME[i - 2];
+		dirfd = nmp_utils_sysctl_open_netdir (ifindex[0],
+		                                       ifname_guess,
+		                                       s);
+	}
+	g_assert (dirfd >= 0);
+	if (s)
+		g_assert_cmpstr (s, ==, IFNAME[0]);
+
+	/* possibly rename the interfaces. */
+	switch (nmtst_get_rand_int () % 4) {
+	case 0:
+		break;
+	case 1:
+		nmtstp_run_command_check ("ip link set %s name %s", IFNAME[0], IFNAME[2]);
+		break;
+	case 2:
+		nmtstp_run_command_check ("ip link set %s name %s", IFNAME[0], IFNAME[2]);
+		nmtstp_run_command_check ("ip link set %s name %s", IFNAME[1], IFNAME[0]);
+		break;
+	}
+
+	/* possibly, resync platform cache (should make no difference). */
+	if (nmtst_get_rand_int () % 2)
+		nm_platform_process_events (PL);
+
+	/* check that we still read the same file. */
+	switch (nmtst_get_rand_int () % 2) {
+	case 0: {
+		gs_free char *c = NULL;
+
+		if (nm_utils_file_get_contents (dirfd, "ifindex", 1*1024*1024, &c, NULL, NULL) < 0)
+			g_assert_not_reached();
+		g_assert_cmpint (ifindex[0], ==, (int) _nm_utils_ascii_str_to_int64 (c, 10, 0, G_MAXINT, -1));
+		break;
+	}
+	case 1: {
+		g_assert_cmpint (ifindex[0], ==, (gint32) nm_platform_sysctl_get_int32 (PL, NMP_SYSCTL_PATHID_NETDIR (dirfd, s ?: "<unknown>", "ifindex"), -1));
+		break;
+	}
+	default:
+		g_assert_not_reached ();
+	}
+
+	nm_platform_process_events (PL);
+	nmtstp_link_del (PL, -1, ifindex[0], NULL);
+	nmtstp_link_del (PL, -1, ifindex[1], NULL);
+}
+
+/*****************************************************************************/
+
+static void
+test_sysctl_netns_switch (void)
+{
+	const char *const IFNAME = "nm-dummy-0";
+	int ifindex, ifindex_tmp;
+	nm_auto_close int dirfd = -1;
+	char ifname_buf[IFNAMSIZ];
+	char *s;
+	gs_unref_object NMPlatform *platform_0 = NULL;
+	gs_unref_object NMPlatform *platform_1 = NULL;
+	gs_unref_object NMPlatform *platform_2 = NULL;
+	nm_auto_pop_netns NMPNetns *netns_pop_1 = NULL;
+	nm_auto_pop_netns NMPNetns *netns_pop_2 = NULL;
+	nm_auto_pop_netns NMPNetns *netns_pop_3 = NULL;
+	NMPlatform *PL;
+	NMPlatform *platforms[3];
+
+	if (_test_netns_check_skip ())
+		return;
+
+	platforms[0] = platform_0 = nm_linux_platform_new (TRUE);
+	platforms[1] = platform_1 = _test_netns_create_platform ();
+	platforms[2] = platform_2 = _test_netns_create_platform ();
+	PL = platforms[nmtst_get_rand_int () % 3];
+
+	nmtstp_netns_select_random (platforms, G_N_ELEMENTS (platforms), &netns_pop_1);
+
+	ifindex = nmtstp_link_dummy_add (PL, FALSE, IFNAME)->ifindex;
+
+	nmtstp_netns_select_random (platforms, G_N_ELEMENTS (platforms), &netns_pop_2);
+
+	s = (nmtst_get_rand_int () % 2) ? NULL : ifname_buf;
+	dirfd = nm_platform_sysctl_open_netdir (PL,
+	                                        ifindex,
+	                                        s);
+	g_assert (dirfd >= 0);
+	if (s)
+		g_assert_cmpstr (s, ==, IFNAME);
+
+	nmtstp_netns_select_random (platforms, G_N_ELEMENTS (platforms), &netns_pop_3);
+
+	/* even if we switch to other namespaces, we can still lookup the path correctly,
+	 * either using dirfd or via the platform instance (which switches namespace as needed). */
+	{
+		gs_free char *c = NULL;
+
+		if (nm_utils_file_get_contents (dirfd, "ifindex", 0, &c, NULL, NULL) < 0)
+			g_assert_not_reached();
+		g_assert_cmpint (ifindex, ==, (int) _nm_utils_ascii_str_to_int64 (c, 10, 0, G_MAXINT, -1));
+	}
+	g_assert_cmpint (ifindex, ==, (gint32) nm_platform_sysctl_get_int32 (PL, NMP_SYSCTL_PATHID_NETDIR (dirfd, s ?: "<unknown>", "ifindex"), -1));
+	g_assert_cmpint (ifindex, ==, (gint32) nm_platform_sysctl_get_int32 (PL, NMP_SYSCTL_PATHID_ABSOLUTE (nm_sprintf_bufa (100, "/sys/class/net/%s/ifindex", IFNAME)), -1));
+
+	/* accessing the path directly, only succeeds iff the current namespace happens to be the namespace
+	 * in which we created the link. */
+	{
+		gs_free char *c = NULL;
+
+		if (nm_utils_file_get_contents (-1, nm_sprintf_bufa (100, "/sys/class/net/%s/ifindex", IFNAME), 0, &c, NULL, NULL) < 0)
+			ifindex_tmp = -1;
+		else
+			ifindex_tmp = _nm_utils_ascii_str_to_int64 (c, 10, 0, G_MAXINT, -2);
+	}
+	if (nmp_netns_get_current () == nm_platform_netns_get (PL))
+		g_assert_cmpint (ifindex_tmp, ==, ifindex);
+	else
+		g_assert_cmpint (ifindex_tmp, ==, -1);
+
+	nmtstp_link_del (PL, FALSE, ifindex, NULL);
+}
+
+/*****************************************************************************/
+
 NMTstpSetupFunc const _nmtstp_setup_platform_func = SETUP;
 
 void
@@ -2378,5 +2541,8 @@ _nmtstp_setup_tests (void)
 		g_test_add_vtable ("/general/netns/set-netns", 0, NULL, _test_netns_setup, test_netns_set_netns, _test_netns_teardown);
 		g_test_add_vtable ("/general/netns/push", 0, NULL, _test_netns_setup, test_netns_push, _test_netns_teardown);
 		g_test_add_vtable ("/general/netns/bind-to-path", 0, NULL, _test_netns_setup, test_netns_bind_to_path, _test_netns_teardown);
+
+		g_test_add_func ("/general/sysctl/rename", test_sysctl_rename);
+		g_test_add_func ("/general/sysctl/netns-switch", test_sysctl_netns_switch);
 	}
 }
diff --git a/src/platform/wifi/wifi-utils-wext.c b/src/platform/wifi/wifi-utils-wext.c
index 3936bbe37c..af8cf2dee6 100644
--- a/src/platform/wifi/wifi-utils-wext.c
+++ b/src/platform/wifi/wifi-utils-wext.c
@@ -577,7 +577,7 @@ wifi_wext_init (const char *iface, int ifindex, gboolean check_scan)
 	wext->parent.set_mesh_channel = wifi_wext_set_mesh_channel;
 	wext->parent.set_mesh_ssid = wifi_wext_set_mesh_ssid;
 
-	wext->fd = socket (PF_INET, SOCK_DGRAM, 0);
+	wext->fd = socket (PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	if (wext->fd < 0)
 		goto error;
 
@@ -662,10 +662,17 @@ wifi_wext_is_wifi (const char *iface)
 	struct iwreq iwr;
 	gboolean is_wifi = FALSE;
 
-	if (!nmp_utils_device_exists (iface))
-		return FALSE;
+	/* performing an ioctl on a non-existing name may cause the automatic
+	 * loading of kernel modules, which should be avoided.
+	 *
+	 * Usually, we should thus make sure that an inteface with this name
+	 * exists.
+	 *
+	 * Note that wifi_wext_is_wifi() has only one caller which just verified
+	 * that an interface with this name exists.
+	 */
 
-	fd = socket (PF_INET, SOCK_DGRAM, 0);
+	fd = socket (PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	if (fd >= 0) {
 		nm_utils_ifname_cpy (iwr.ifr_ifrn.ifrn_name, iface);
 		if (ioctl (fd, SIOCGIWNAME, &iwr) == 0)
diff --git a/src/platform/wifi/wifi-utils.c b/src/platform/wifi/wifi-utils.c
index de858e499a..b8da02c15e 100644
--- a/src/platform/wifi/wifi-utils.c
+++ b/src/platform/wifi/wifi-utils.c
@@ -26,6 +26,7 @@
 #include <sys/stat.h>
 #include <stdio.h>
 #include <string.h>
+#include <fcntl.h>
 
 #include "wifi-utils-private.h"
 #include "wifi-utils-nl80211.h"
@@ -34,6 +35,8 @@
 #endif
 #include "nm-core-utils.h"
 
+#include "platform/nm-platform-utils.h"
+
 gpointer
 wifi_data_new (const char *iface, int ifindex, gsize len)
 {
@@ -180,30 +183,19 @@ wifi_utils_deinit (WifiData *data)
 }
 
 gboolean
-wifi_utils_is_wifi (const char *iface)
+wifi_utils_is_wifi (int dirfd, const char *ifname)
 {
-	char phy80211_path[NM_STRLEN ("/sys/class/net/123456789012345/phy80211\0") + 100 /*safety*/];
-	struct stat s;
-
-	g_return_val_if_fail (iface != NULL, FALSE);
-
-	nm_sprintf_buf (phy80211_path,
-	                "/sys/class/net/%s/phy80211",
-	                NM_ASSERT_VALID_PATH_COMPONENT (iface));
-	nm_assert (strlen (phy80211_path) < sizeof (phy80211_path) - 1);
+	g_return_val_if_fail (dirfd >= 0, FALSE);
 
-	if ((stat (phy80211_path, &s) == 0 && (s.st_mode & S_IFDIR)))
+	if (faccessat (dirfd, "phy80211", F_OK, 0) == 0)
 		return TRUE;
-
 #if HAVE_WEXT
-	if (wifi_wext_is_wifi (iface))
+	if (wifi_wext_is_wifi (ifname))
 		return TRUE;
 #endif
-
 	return FALSE;
 }
 
-
 /* OLPC Mesh-only functions */
 
 guint32
diff --git a/src/platform/wifi/wifi-utils.h b/src/platform/wifi/wifi-utils.h
index 8e2b93f1f0..4fd5a80bbe 100644
--- a/src/platform/wifi/wifi-utils.h
+++ b/src/platform/wifi/wifi-utils.h
@@ -28,7 +28,7 @@
 
 typedef struct WifiData WifiData;
 
-gboolean wifi_utils_is_wifi (const char *iface);
+gboolean wifi_utils_is_wifi (int dirfd, const char *ifname);
 
 WifiData *wifi_utils_init (const char *iface, int ifindex, gboolean check_scan);
 
diff --git a/src/ppp/nm-ppp-manager.c b/src/ppp/nm-ppp-manager.c
index c8d43299d9..e33d9fe6fc 100644
--- a/src/ppp/nm-ppp-manager.c
+++ b/src/ppp/nm-ppp-manager.c
@@ -148,7 +148,7 @@ monitor_cb (gpointer user_data)
 		if (errno != ENODEV)
 			_LOGW ("could not read ppp stats: %s", strerror (errno));
 	} else {
-		g_signal_emit (manager, signals[STATS], 0, 
+		g_signal_emit (manager, signals[STATS], 0,
 		               stats.p.ppp_ibytes,
 		               stats.p.ppp_obytes);
 	}
@@ -165,7 +165,7 @@ monitor_stats (NMPPPManager *manager)
 	if (priv->monitor_fd >= 0)
 		return;
 
-	priv->monitor_fd = socket (AF_INET, SOCK_DGRAM, 0);
+	priv->monitor_fd = socket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	if (priv->monitor_fd >= 0) {
 		g_warn_if_fail (priv->monitor_id == 0);
 		if (priv->monitor_id)
diff --git a/src/settings/nm-inotify-helper.c b/src/settings/nm-inotify-helper.c
index 44a102b059..a0432a25c0 100644
--- a/src/settings/nm-inotify-helper.c
+++ b/src/settings/nm-inotify-helper.c
@@ -144,7 +144,7 @@ init_inotify (NMInotifyHelper *self)
 	GIOChannel *channel;
 	guint source_id;
 
-	priv->ifd = inotify_init ();
+	priv->ifd = inotify_init1 (IN_CLOEXEC);
 	if (priv->ifd == -1) {
 		int errsv = errno;
 
diff --git a/src/settings/plugins/ifcfg-rh/shvar.c b/src/settings/plugins/ifcfg-rh/shvar.c
index 22c942fce2..28989e1dfc 100644
--- a/src/settings/plugins/ifcfg-rh/shvar.c
+++ b/src/settings/plugins/ifcfg-rh/shvar.c
@@ -641,11 +641,11 @@ svOpenFileInternal (const char *name, gboolean create, GError **error)
 
 	s->fd = -1;
 	if (create)
-		s->fd = open (name, O_RDWR); /* NOT O_CREAT */
+		s->fd = open (name, O_RDWR | O_CLOEXEC); /* NOT O_CREAT */
 
 	if (!create || s->fd == -1) {
 		/* try read-only */
-		s->fd = open (name, O_RDONLY); /* NOT O_CREAT */
+		s->fd = open (name, O_RDONLY | O_CLOEXEC); /* NOT O_CREAT */
 		if (s->fd == -1)
 			errsv = errno;
 		else
@@ -1017,7 +1017,7 @@ svWriteFile (shvarFile *s, int mode, GError **error)
 
 	if (s->modified) {
 		if (s->fd == -1)
-			s->fd = open (s->fileName, O_WRONLY | O_CREAT, mode);
+			s->fd = open (s->fileName, O_WRONLY | O_CREAT | O_CLOEXEC, mode);
 		if (s->fd == -1) {
 			int errsv = errno;
 
diff --git a/src/settings/plugins/ifupdown/nms-ifupdown-interface-parser.c b/src/settings/plugins/ifupdown/nms-ifupdown-interface-parser.c
index df6d248c03..e86f521647 100644
--- a/src/settings/plugins/ifupdown/nms-ifupdown-interface-parser.c
+++ b/src/settings/plugins/ifupdown/nms-ifupdown-interface-parser.c
@@ -117,7 +117,7 @@ _recursive_ifparser (const char *eni_file, int quiet)
 			nm_log_warn (LOGD_SETTINGS, "interfaces file %s doesn't exist\n", eni_file);
 		return;
 	}
-	inp = fopen (eni_file, "r");
+	inp = fopen (eni_file, "re");
 	if (inp == NULL) {
 		if (!quiet)
 			nm_log_warn (LOGD_SETTINGS, "Can't open %s\n", eni_file);
diff --git a/src/tests/test-general-with-expect.c b/src/tests/test-general-with-expect.c
index 9338557b41..fbed7799b1 100644
--- a/src/tests/test-general-with-expect.c
+++ b/src/tests/test-general-with-expect.c
@@ -26,6 +26,7 @@
 #include <netinet/ether.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <fcntl.h>
 
 #include "NetworkManagerUtils.h"
 #include "nm-multi-index.h"
@@ -173,7 +174,7 @@ test_nm_utils_kill_child_create_and_join_pgroup (void)
 	int pipefd[2];
 	pid_t pgid;
 
-	err = pipe (pipefd);
+	err = pipe2 (pipefd, O_CLOEXEC);
 	g_assert (err == 0);
 
 	pgid = fork();