Attachment 693874 Details for Bug 877084 – [PATCH] fix the race in getting hostname through reverse-lookup

[patch] [PATCH] fix the race in getting hostname through reverse-lookup

0001-policy-dns-fix-a-race-in-looking-up-hostname-and-upd.patch (text/plain), 8.55 KB, created by Jirka Klimes on 2013-02-06 11:48:12 UTC

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Creator: Jirka Klimes

Created: 2013-02-06 11:48:12 UTC

Size: 8.55 KB

patch

obsolete

>From dc8696e79d31b659f8d7a8386b3731065a0f33c0 Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ji=C5=99=C3=AD=20Klime=C5=A1?= <jklimes@redhat.com>
>Date: Tue, 5 Feb 2013 17:29:15 +0100
>Subject: [PATCH 1/2] policy,dns: fix a race in looking up hostname and
> updating DNS (rh #877084)
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>"config-changed" signal is added to dns-manager and emited when resolv.conf is
>changed. Policy listens for the signal and restarts reverse-lookup in order to
>get correct results.
>
>Signed-off-by: JiÅÃ KlimeÅ¡ <jklimes@redhat.com>
>---
> src/dns-manager/nm-dns-manager.c | 27 ++++++++++++++--
> src/dns-manager/nm-dns-manager.h |  5 ++-
> src/nm-policy.c                  | 67 ++++++++++++++++++++++++++++++++++++++--
> 3 files changed, 93 insertions(+), 6 deletions(-)
>
>diff --git a/src/dns-manager/nm-dns-manager.c b/src/dns-manager/nm-dns-manager.c
>index 38691f3..1e67616 100644
>--- a/src/dns-manager/nm-dns-manager.c
>+++ b/src/dns-manager/nm-dns-manager.c
>@@ -16,7 +16,7 @@
>  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
>  *
>  * Copyright (C) 2004 - 2005 Colin Walters <walters@redhat.com>
>- * Copyright (C) 2004 - 2012 Red Hat, Inc.
>+ * Copyright (C) 2004 - 2013 Red Hat, Inc.
>  * Copyright (C) 2005 - 2008 Novell, Inc.
>  *   and others
>  */
>@@ -81,6 +81,14 @@ typedef struct {
> 	char *last_iface;
> } NMDnsManagerPrivate;
> 
>+enum {
>+	CONFIG_CHANGED,
>+
>+	LAST_SIGNAL
>+};
>+
>+static guint signals[LAST_SIGNAL] = { 0 };
>+
> 
> typedef struct {
> 	GPtrArray *nameservers;
>@@ -761,6 +769,10 @@ update_dns (NMDnsManager *self,
> 	if (success == FALSE)
> 		success = update_resolv_conf (domain, searches, nameservers, iface, error);
> 
>+	/* signal that resolv.conf was changed */
>+	if (success)
>+		g_signal_emit (self, signals[CONFIG_CHANGED], 0);
>+
> 	if (searches)
> 		g_strfreev (searches);
> 	if (nameservers)
>@@ -1164,9 +1176,20 @@ nm_dns_manager_class_init (NMDnsManagerClass *klass)
> {
> 	GObjectClass *object_class = G_OBJECT_CLASS (klass);
> 
>+	g_type_class_add_private (object_class, sizeof (NMDnsManagerPrivate));
>+
>+	/* virtual methods */
> 	object_class->dispose = dispose;
> 	object_class->finalize = finalize;
> 
>-	g_type_class_add_private (object_class, sizeof (NMDnsManagerPrivate));
>+	/* signals */
>+	signals[CONFIG_CHANGED] =
>+		g_signal_new ("config-changed",
>+		              G_OBJECT_CLASS_TYPE (object_class),
>+		              G_SIGNAL_RUN_FIRST,
>+		              G_STRUCT_OFFSET (NMDnsManagerClass, config_changed),
>+		              NULL, NULL,
>+		              g_cclosure_marshal_VOID__VOID,
>+		              G_TYPE_NONE, 0);
> }
> 
>diff --git a/src/dns-manager/nm-dns-manager.h b/src/dns-manager/nm-dns-manager.h
>index f559865..275c4cf 100644
>--- a/src/dns-manager/nm-dns-manager.h
>+++ b/src/dns-manager/nm-dns-manager.h
>@@ -16,7 +16,7 @@
>  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
>  *
>  * Copyright (C) 2004 - 2005 Colin Walters <walters@redhat.com>
>- * Copyright (C) 2004 - 2010 Red Hat, Inc.
>+ * Copyright (C) 2004 - 2013 Red Hat, Inc.
>  * Copyright (C) 2005 - 2008 Novell, Inc.
>  *   and others
>  */
>@@ -60,6 +60,9 @@ typedef struct {
> 
> typedef struct {
> 	GObjectClass parent;
>+
>+	/* Signals */
>+	void (*config_changed) (NMDnsManager *mgr);
> } NMDnsManagerClass;
> 
> GType nm_dns_manager_get_type (void);
>diff --git a/src/nm-policy.c b/src/nm-policy.c
>index 420a941..342ecb7 100644
>--- a/src/nm-policy.c
>+++ b/src/nm-policy.c
>@@ -15,7 +15,7 @@
>  * with this program; if not, write to the Free Software Foundation, Inc.,
>  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
>  *
>- * Copyright (C) 2004 - 2012 Red Hat, Inc.
>+ * Copyright (C) 2004 - 2013 Red Hat, Inc.
>  * Copyright (C) 2007 - 2008 Novell, Inc.
>  */
> 
>@@ -62,6 +62,10 @@ struct NMPolicy {
> 	NMDevice *default_device6;
> 
> 	HostnameThread *lookup;
>+	guint32 lookup_ipv4_addr;          /* IPv4 for reverse lookup */
>+	struct in6_addr *lookup_ipv6_addr; /* IPv6 for reverse lookup */
>+	NMDnsManager *dns_manager;
>+	gulong config_changed_id;
> 
> 	gint reset_retries_id;  /* idle handler for resetting the retries count */
> 
>@@ -237,6 +241,15 @@ _set_hostname (NMPolicy *policy,
> 	 * there was no valid hostname to start with.
> 	 */
> 
>+	/* Clear lookup adresses if we have a hostname, so that we didn't
>+	 * restart reverse lookup thread later.
>+	 */
>+	if (new_hostname) {
>+		policy->lookup_ipv4_addr = 0;
>+		g_free (policy->lookup_ipv6_addr);
>+		policy->lookup_ipv6_addr = NULL;
>+	}
>+
> 	/* Don't change the hostname or update DNS this is the first time we're
> 	 * trying to change the hostname, and it's not actually changing.
> 	 */
>@@ -398,7 +411,8 @@ update_system_hostname (NMPolicy *policy, NMDevice *best4, NMDevice *best6)
> 		g_assert (addr4); /* checked for > 1 address above */
> 
> 		/* Start the hostname lookup thread */
>-		policy->lookup = hostname4_thread_new (nm_ip4_address_get_address (addr4), lookup_callback, policy);
>+		policy->lookup_ipv4_addr = nm_ip4_address_get_address (addr4);
>+		policy->lookup = hostname4_thread_new (policy->lookup_ipv4_addr, lookup_callback, policy);
> 	} else if (best6) {
> 		NMIP6Config *ip6_config;
> 		NMIP6Address *addr6;
>@@ -416,7 +430,9 @@ update_system_hostname (NMPolicy *policy, NMDevice *best4, NMDevice *best6)
> 		g_assert (addr6); /* checked for > 1 address above */
> 
> 		/* Start the hostname lookup thread */
>-		policy->lookup = hostname6_thread_new (nm_ip6_address_get_address (addr6), lookup_callback, policy);
>+		policy->lookup_ipv6_addr = g_malloc0 (sizeof (struct in6_addr));
>+		memcpy (policy->lookup_ipv6_addr, nm_ip6_address_get_address (addr6), sizeof (struct in6_addr));
>+		policy->lookup = hostname6_thread_new (policy->lookup_ipv6_addr, lookup_callback, policy);
> 	}
> 
> 	if (!policy->lookup) {
>@@ -1792,6 +1808,43 @@ firewall_started (NMFirewallManager *manager,
> }
> 
> static void
>+dns_config_changed (NMDnsManager *dns_manager, gpointer user_data)
>+{
>+	NMPolicy *policy = (NMPolicy *) user_data;
>+
>+	/* Restart a thread for reverse-DNS lookup after we are signalled that
>+	 * DNS changed. Because the result from a previous run may not be right
>+	 * (race in updating DNS and doing the reverse lookup).
>+	 */
>+
>+	/* Stop a lookup thread if any. */
>+	if (policy->lookup) {
>+		hostname_thread_kill (policy->lookup);
>+		policy->lookup = NULL;
>+	}
>+
>+	/* Re-start the hostname lookup thread if we don't have hostname yet. */
>+	if (policy->lookup_ipv4_addr) {
>+		char buf[INET_ADDRSTRLEN];
>+		struct in_addr addr = { .s_addr = policy->lookup_ipv4_addr };
>+		
>+		if (!inet_ntop (AF_INET, &addr, buf, sizeof (buf)))
>+			strcpy (buf, "(unknown)");
>+		nm_log_dbg (LOGD_DNS, "restarting IPv4 reverse-lookup thread for address %s'", buf);
>+
>+		policy->lookup = hostname4_thread_new (policy->lookup_ipv4_addr, lookup_callback, policy);
>+	} else if (policy->lookup_ipv6_addr) {
>+		char buf[INET6_ADDRSTRLEN];
>+
>+		if (!inet_ntop (AF_INET6, policy->lookup_ipv6_addr, buf, sizeof (buf)))
>+			strcpy (buf, "(unknown)");
>+		nm_log_dbg (LOGD_DNS, "restarting IPv6 reverse-lookup thread for address %s'", buf);
>+
>+		policy->lookup = hostname6_thread_new (policy->lookup_ipv6_addr, lookup_callback, policy);
>+	}
>+}
>+
>+static void
> connection_updated (NMSettings *settings,
>                     NMConnection *connection,
>                     gpointer user_data)
>@@ -1917,6 +1970,10 @@ nm_policy_new (NMManager *manager, NMSettings *settings)
> 	                       G_CALLBACK (firewall_started), policy);
> 	policy->fw_started_id = id;
> 
>+	policy->dns_manager = nm_dns_manager_get (NULL);
>+	policy->config_changed_id = g_signal_connect (policy->dns_manager, "config-changed",
>+	                                              G_CALLBACK (dns_config_changed), policy);
>+
> 	_connect_manager_signal (policy, "state-changed", global_state_changed);
> 	_connect_manager_signal (policy, "notify::" NM_MANAGER_HOSTNAME, hostname_changed);
> 	_connect_manager_signal (policy, "notify::" NM_MANAGER_SLEEPING, sleeping_changed);
>@@ -1955,6 +2012,7 @@ nm_policy_destroy (NMPolicy *policy)
> 		hostname_thread_kill (policy->lookup);
> 		policy->lookup = NULL;
> 	}
>+	g_free (policy->lookup_ipv6_addr);
> 
> 	g_slist_foreach (policy->pending_activation_checks, (GFunc) activate_data_free, NULL);
> 	g_slist_free (policy->pending_activation_checks);
>@@ -1965,6 +2023,9 @@ nm_policy_destroy (NMPolicy *policy)
> 	g_signal_handler_disconnect (policy->fw_manager, policy->fw_started_id);
> 	g_object_unref (policy->fw_manager);
> 
>+	g_signal_handler_disconnect (policy->dns_manager, policy->config_changed_id);
>+	g_object_unref (policy->dns_manager);
>+
> 	for (iter = policy->manager_ids; iter; iter = g_slist_next (iter))
> 		g_signal_handler_disconnect (policy->manager, GPOINTER_TO_UINT (iter->data));
> 	g_slist_free (policy->manager_ids);
>-- 
>1.7.11.7
>

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Attachments on bug 877084: 664980 | 693874