Define iptables error

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "iptables"
-version = "0.4.0"
+version = "0.4.1"
 authors = ["Navid Fathollahzade <[email protected]>", "Pit Kleyersburg <[email protected]>"]
 edition = "2018"
 description = "Rust bindings for iptables"

src/error.rs

@@ -0,0 +1,27 @@
+use std::convert::From;
+use std::error::Error;
+use std::fmt;
+use std::process::Output;
+
+#[derive(Debug)]
+pub struct IptablesError {
+    pub code: i32,
+    pub msg: String,
+}
+
+impl fmt::Display for IptablesError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "code: {}, msg: {}", self.code, self.msg)
+    }
+}
+
+impl From<Output> for IptablesError {
+    fn from(output: Output) -> Self {
+        Self {
+            code: output.status.code().unwrap_or(-1),
+            msg: String::from_utf8_lossy(output.stderr.as_slice()).into(),
+        }
+    }
+}
+
+impl Error for IptablesError {}

src/lib.rs

@@ -14,9 +14,13 @@
 //! assert!(ipt.delete_chain("nat", "NEWCHAINNAME").is_ok());
 //! ```
 
+pub mod error;
+
+use error::IptablesError;
 use lazy_static::lazy_static;
 use nix::fcntl::{flock, FlockArg};
 use regex::{Match, Regex};
+use std::convert::From;
 use std::error::Error;
 use std::ffi::OsStr;
 use std::fs::File;
@@ -60,12 +64,7 @@ fn error_from_str(msg: &str) -> Box<dyn Error> {
 
 fn output_to_result(output: Output) -> Result<(), Box<dyn Error>> {
     if !output.status.success() {
-        let msg = format!(
-            "iptables returned non-zero status code: {} - {}",
-            output.status.code().unwrap_or(-1),
-            String::from_utf8_lossy(output.stderr.as_slice()),
-        );
-        return Err(error_from_str(msg.as_str()));
+        return Err(Box::new(IptablesError::from(output)));
     }
     Ok(())
 }