Merge branch 'fix-systemd-resolved-detection'

2 files changed, 30 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91d202aeaa..b5c2b0abdf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -60,6 +60,9 @@ Line wrap the file at 100 chars.                                              Th
 #### Windows
 - Add better offline detection
 
+#### Linux
+- Fix `systemd-resolved` detection by better compraing `/etc/resolv.conf` symlinks.
+
 
 ## [2019.4] - 2019-05-08
 This release is identical to 2019.4-beta1
diff --git a/talpid-core/src/dns/linux/systemd_resolved.rs b/talpid-core/src/dns/linux/systemd_resolved.rs
index a633cea91e..1cd953bea6 100644
--- a/talpid-core/src/dns/linux/systemd_resolved.rs
+++ b/talpid-core/src/dns/linux/systemd_resolved.rs
@@ -54,7 +54,13 @@ pub enum Error {
     MatchDBusTypeError(#[error(cause)] dbus::arg::TypeMismatchError),
 }
 
-const DYNAMIC_RESOLV_CONF_PATH: &str = "/run/systemd/resolve/resolv.conf";
+lazy_static! {
+    static ref RESOLVED_PATHS: Vec<&'static Path> = vec![
+        Path::new("/run/systemd/resolve/stub-resolv.conf"),
+        Path::new("/run/systemd/resolve/resolv.conf"),
+    ];
+}
+
 const RESOLVED_DNS_SERVER_ADDRESS: [u8; 4] = [127, 0, 0, 53];
 
 const RESOLVED_BUS: &str = "org.freedesktop.resolve1";
@@ -103,7 +109,7 @@ impl SystemdResolved {
 
     fn ensure_resolv_conf_is_resolved_symlink() -> Result<()> {
         let is_correct_symlink = fs::read_link(RESOLV_CONF_PATH)
-            .map(|resolv_conf_target| resolv_conf_target == Path::new(DYNAMIC_RESOLV_CONF_PATH))
+            .map(|resolv_conf_target| Self::compare_resolvconf_symlink(&resolv_conf_target))
             .unwrap_or_else(|_| false);
         if is_correct_symlink {
             Ok(())
@@ -112,6 +118,25 @@ impl SystemdResolved {
         }
     }
 
+    fn compare_resolvconf_symlink(link_path: &Path) -> bool {
+        // if link path is relative to /etc/resolv.conf, resolve the path and compare it.
+        if link_path.is_relative() {
+            match Path::new("/etc/").join(link_path).canonicalize() {
+                Ok(link_destination) => RESOLVED_PATHS.contains(&link_destination.as_ref()),
+                Err(e) => {
+                    log::error!(
+                        "Failed to canonicalize resolv conf path {} - {}",
+                        link_path.display(),
+                        e
+                    );
+                    false
+                }
+            }
+        } else {
+            RESOLVED_PATHS.contains(&link_path)
+        }
+    }
+
     fn ensure_resolv_conf_has_resolved_dns() -> Result<()> {
         let resolv_conf_contents =
             fs::read_to_string(RESOLV_CONF_PATH).map_err(Error::ReadResolvConfFailed)?;