From 486fc0eadede5895b823e785d3e50ac16c0e185c Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Fri, 3 Jun 2016 10:33:54 +0200 Subject: [PATCH] dns: follow resolv.conf if it is a symlink for 'rc-manager=file' Until before 1.2.0, NetworkManager would always write resolv.conf as file, but if /etc/resolv.conf was a symlink, it would follow the link instead of replacing it with a file ([1], [2]). With 1.2.0, we initially dropped that behavior and added a new 'rc-manager=none' which writes resolv.conf to /var/run/NetworkManager and symlinks resolv.conf [3]. In case resolv.conf being already a symlink to another target, it would not be replaced [4]. Later, we added 'rc-manager=file', which always writes /etc/resolv.conf as file [5]. With 1.4.0, we will rename 'rc-manager=none' to 'rc-manager=symlink' [6]. This commit now fixes 'rc-manager=file' to restores the pre-1.2 behavior and follow symlinks. [1] 5761e328b81ce8894c2657ce0994ba401923ba35 [2] https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/324233 [3] 4805be2ed27b71a6099477d86dbc109adb41b819 [4] 583568e12f9e580cd2903811637c9f9b7a2f1088 [5] 288799713dc78bc45e2b0a9cf41d228f5d95315f [6] cd6a469668028fbc347919ed3580275f9894a1f2 https://github.com/NetworkManager/NetworkManager/pull/7 (cherry picked from commit 718fd2243690b8c72dd1cb32f67114f304542082) --- man/NetworkManager.conf.xml | 4 +++- src/dns-manager/nm-dns-manager.c | 14 ++++++++++---- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/man/NetworkManager.conf.xml b/man/NetworkManager.conf.xml index ee9b5679f3..ea0573fa5f 100644 --- a/man/NetworkManager.conf.xml +++ b/man/NetworkManager.conf.xml @@ -324,7 +324,9 @@ no-auto-default=* /etc/resolv.conf to its private resolv.conf file in the runtime state directory. file: NetworkManager will write - /etc/resolv.conf as file. + /etc/resolv.conf as file. If it finds + a symlink, it will follow the symlink and update the target + instead. resolvconf: NetworkManager will run resolvconf to update the DNS configuration. netconfig: NetworkManager will run diff --git a/src/dns-manager/nm-dns-manager.c b/src/dns-manager/nm-dns-manager.c index dfeece6240..8134f2f4a4 100644 --- a/src/dns-manager/nm-dns-manager.c +++ b/src/dns-manager/nm-dns-manager.c @@ -674,6 +674,8 @@ update_resolv_conf (NMDnsManager *self, gs_free char *content = NULL; SpawnResult write_file_result = SR_SUCCESS; int errsv; + const char *rc_path = _PATH_RESCONF; + nm_auto_free char *rc_path_real = NULL; /* If we are not managing /etc/resolv.conf and it points to * MY_RESOLV_CONF, don't write the private DNS configuration to @@ -697,18 +699,22 @@ update_resolv_conf (NMDnsManager *self, if (rc_manager == NM_DNS_MANAGER_RESOLV_CONF_MAN_FILE) { GError *local = NULL; + rc_path_real = realpath (rc_path, NULL); + if (rc_path_real) + rc_path = rc_path_real; + /* we first write to /etc/resolv.conf directly. If that fails, * we still continue to write to runstatedir but remember the * error. */ - if (!g_file_set_contents (_PATH_RESCONF, content, -1, &local)) { + if (!g_file_set_contents (rc_path, content, -1, &local)) { _LOGT ("update-resolv-conf: write to %s failed (rc-manager=%s, %s)", - _PATH_RESCONF, _rc_manager_to_string (rc_manager), local->message); + rc_path, _rc_manager_to_string (rc_manager), local->message); write_file_result = SR_ERROR; g_propagate_error (error, local); error = NULL; } else { _LOGT ("update-resolv-conf: write to %s succeeded (rc-manager=%s)", - _PATH_RESCONF, _rc_manager_to_string (rc_manager)); + rc_path, _rc_manager_to_string (rc_manager)); } } @@ -766,7 +772,7 @@ update_resolv_conf (NMDnsManager *self, if (rc_manager == NM_DNS_MANAGER_RESOLV_CONF_MAN_FILE) { _LOGT ("update-resolv-conf: write internal file %s succeeded (rc-manager=%s)", - _PATH_RESCONF, _rc_manager_to_string (rc_manager)); + rc_path, _rc_manager_to_string (rc_manager)); return write_file_result; }