exec: use canonicalize to check for file existance too. better error message.

src/main.rs

@@ -253,18 +253,26 @@ fn exec(entryname: &str, cmdargs: &Vec<String>) -> std::io::Result<()> {
     let basedir: String = String::from("/etc/raou.d/");
     let filepath: String = basedir.to_string() + entryname;
 
-    let realpath = fs::canonicalize(&filepath)?;
+    let realpath = fs::canonicalize(&filepath);
-    if !realpath.starts_with(basedir) {
+    match realpath {
+        Ok(p) => {
+            if !p.starts_with(basedir) {
                 return Err(std::io::Error::new(
                     ErrorKind::InvalidInput,
                     "Specified entry is outside base directory",
                 ));
             }
-    if !std::path::Path::new(&filepath).exists() {
+        }
+        Err(e) => {
+            if e.kind() == ErrorKind::NotFound {
                 return Err(std::io::Error::new(
                     ErrorKind::NotFound,
-            format!("The entry {} does not exist", filepath),
+                    format!("The entry {} does not exist", entryname),
                 ));
+            } else {
+                return Err(e);
+            }
+        }
     }
     let entry: Entry = create_entry_from_file(&filepath)?;
     let destuserpasswd: Passwd = getpwnam(&entry.dest_user)?;