Remove unnecessary error types

Executable without parent directory should never happen. In either case,
the current working directory is used as a fallback and the error is
logged. This is the same procedure used for the resources directory.

talpid-core/src/tunnel/mod.rs

@@ -26,14 +26,6 @@ mod errors {
             TunnelMonitoringError {
                 description("Error while setting up or processing events from the VPN tunnel")
             }
-            /// Failed to get the current executable path.
-            ExecutablePathInaccessible {
-                description("Error while reading current executable path")
-            }
-            /// Obtained executable path doesn't have a parent directory.
-            ExecutableHasNoParentDir {
-                description("Executable path has no directories")
-            }
             /// The OpenVPN plugin was not found.
             PluginNotFound {
                 description("No OpenVPN plugin found")
@@ -199,7 +191,7 @@ impl TunnelMonitor {
 
     fn get_plugin_path() -> Result<PathBuf> {
         let library = Self::get_library_name().chain_err(|| ErrorKind::PluginNotFound)?;
-        let mut path = Self::get_executable_dir().chain_err(|| ErrorKind::PluginNotFound)?;
+        let mut path = Self::get_executable_dir();
 
         path.push(library);
 
@@ -211,13 +203,20 @@ impl TunnelMonitor {
         }
     }
 
-    fn get_executable_dir() -> Result<PathBuf> {
-        let exe_path = env::current_exe().chain_err(|| ErrorKind::ExecutablePathInaccessible)?;
-
-        exe_path
-            .parent()
-            .map(Path::to_path_buf)
-            .ok_or(ErrorKind::ExecutableHasNoParentDir.into())
+    fn get_executable_dir() -> PathBuf {
+        match env::current_exe() {
+            Ok(mut path) => {
+                path.pop();
+                path
+            }
+            Err(e) => {
+                error!(
+                    "Failed finding the install directory. Using working directory: {}",
+                    e
+                );
+                PathBuf::from(".")
+            }
+        }
     }
 
     fn get_library_name() -> Result<&'static str> {