Build out a new error type

openssl/src/ssl/error.rs

@@ -3,12 +3,136 @@ pub use self::OpensslError::*;
 
 use libc::c_ulong;
 use std::error;
+use std::error::Error as StdError;
 use std::fmt;
 use std::ffi::CStr;
 use std::io;
+use std::str;
 
 use ffi;
 
+/// An SSL error.
+#[derive(Debug)]
+pub enum Error {
+    /// The SSL session has been closed by the other end
+    ZeroReturn,
+    /// An attempt to read data from the underlying socket returned
+    /// `WouldBlock`. Wait for read readiness and reattempt the operation.
+    WantRead(io::Error),
+    /// An attempt to write data from the underlying socket returned
+    /// `WouldBlock`. Wait for write readiness and reattempt the operation.
+    WantWrite(io::Error),
+    #[doc(hidden)] // unused for now
+    WantX509Lookup,
+    /// An error reported by the underlying stream.
+    Stream(io::Error),
+    /// An error in the OpenSSL library.
+    Ssl(Vec<OpenSslError>),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        try!(fmt.write_str(self.description()));
+        match *self {
+            Error::Stream(ref err) => write!(fmt, ": {}", err),
+            Error::WantRead(ref err) => write!(fmt, ": {}", err),
+            Error::WantWrite(ref err) => write!(fmt, ": {}", err),
+            Error::Ssl(ref errs) => {
+                let mut first = true;
+                for err in errs {
+                    if first {
+                        try!(fmt.write_str(": "));
+                        first = false;
+                    } else {
+                        try!(fmt.write_str(", "));
+                    }
+                    try!(fmt.write_str(&err.reason()))
+                }
+                Ok(())
+            }
+            _ => Ok(())
+        }
+    }
+}
+
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        match *self {
+            Error::ZeroReturn => "The SSL session was closed by the other end",
+            Error::WantRead(_) => "A read attempt returned a `WouldBlock` error",
+            Error::WantWrite(_) => "A write attempt returned a `WouldBlock` error",
+            Error::WantX509Lookup => "The client certificate callback requested to be called again",
+            Error::Stream(_) => "The underlying stream reported an error",
+            Error::Ssl(_) => "The OpenSSL library reported an error",
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match *self {
+            Error::WantRead(ref err) => Some(err),
+            Error::WantWrite(ref err) => Some(err),
+            Error::Stream(ref err) => Some(err),
+            _ => None
+        }
+    }
+}
+
+/// An error reported from OpenSSL.
+pub struct OpenSslError(c_ulong);
+
+impl OpenSslError {
+    /// Returns the contents of the OpenSSL error stack.
+    pub fn get_stack() -> Vec<OpenSslError> {
+        ffi::init();
+
+        let mut errs = vec!();
+        loop {
+            match unsafe { ffi::ERR_get_error() } {
+                0 => break,
+                err => errs.push(OpenSslError(err))
+            }
+        }
+        errs
+    }
+
+    /// Returns the name of the library reporting the error.
+    pub fn library(&self) -> &'static str {
+        get_lib(self.0)
+    }
+
+    /// Returns the name of the function reporting the error.
+    pub fn function(&self) -> &'static str {
+        get_func(self.0)
+    }
+
+    /// Returns the reason for the error.
+    pub fn reason(&self) -> &'static str {
+        get_reason(self.0)
+    }
+}
+
+impl fmt::Debug for OpenSslError {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("OpenSslError")
+           .field("library", &self.library())
+           .field("function", &self.function())
+           .field("reason", &self.reason())
+           .finish()
+    }
+}
+
+impl fmt::Display for OpenSslError {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.write_str(&self.reason())
+    }
+}
+
+impl error::Error for OpenSslError {
+    fn description(&self) -> &str {
+        "An OpenSSL error"
+    }
+}
+
 /// An SSL error
 #[derive(Debug)]
 pub enum SslError {
@@ -115,27 +239,27 @@ pub enum OpensslError {
     }
 }
 
-fn get_lib(err: c_ulong) -> String {
+fn get_lib(err: c_ulong) -> &'static str {
     unsafe {
         let cstr = ffi::ERR_lib_error_string(err);
-        let bytes = CStr::from_ptr(cstr as *const _).to_bytes().to_vec();
-        String::from_utf8(bytes).unwrap()
+        let bytes = CStr::from_ptr(cstr as *const _).to_bytes();
+        str::from_utf8(bytes).unwrap()
     }
 }
 
-fn get_func(err: c_ulong) -> String {
+fn get_func(err: c_ulong) -> &'static str {
     unsafe {
         let cstr = ffi::ERR_func_error_string(err);
-        let bytes = CStr::from_ptr(cstr as *const _).to_bytes().to_vec();
-        String::from_utf8(bytes).unwrap()
+        let bytes = CStr::from_ptr(cstr as *const _).to_bytes();
+        str::from_utf8(bytes).unwrap()
     }
 }
 
-fn get_reason(err: c_ulong) -> String {
+fn get_reason(err: c_ulong) -> &'static str {
     unsafe {
         let cstr = ffi::ERR_reason_error_string(err);
-        let bytes = CStr::from_ptr(cstr as *const _).to_bytes().to_vec();
-        String::from_utf8(bytes).unwrap()
+        let bytes = CStr::from_ptr(cstr as *const _).to_bytes();
+        str::from_utf8(bytes).unwrap()
     }
 }
 
@@ -161,9 +285,9 @@ impl SslError {
     fn from_error_code(err: c_ulong) -> OpensslError {
         ffi::init();
         UnknownError {
-            library: get_lib(err),
-            function: get_func(err),
-            reason: get_reason(err)
+            library: get_lib(err).to_owned(),
+            function: get_func(err).to_owned(),
+            reason: get_reason(err).to_owned()
         }
     }
 }

openssl/src/ssl/mod.rs

@@ -22,7 +22,7 @@ use std::marker::PhantomData;
 use ffi;
 use ffi_extras;
 use dh::DH;
-use ssl::error::{NonblockingSslError, SslError, StreamError, OpenSslErrors};
+use ssl::error::{NonblockingSslError, SslError, StreamError, OpenSslErrors, OpenSslError};
 use x509::{X509StoreContext, X509FileType, X509};
 use crypto::pkey::PKey;
 
@@ -31,6 +31,9 @@ mod bio;
 #[cfg(test)]
 mod tests;
 
+#[doc(inline)]
+pub use ssl::error::Error;
+
 extern "C" {
     fn rust_SSL_clone(ssl: *mut ffi::SSL);
 }
@@ -954,7 +957,17 @@ impl<S: Read+Write> SslStream<S> {
         if ret > 0 {
             Ok(stream)
         } else {
-            Err(stream.make_error(ret))
+            match stream.make_old_error(ret) {
+                SslError::StreamError(e) => {
+                    // This is fine - nonblocking sockets will finish the handshake in read/write
+                    if e.kind() == io::ErrorKind::WouldBlock {
+                        Ok(stream)
+                    } else {
+                        Err(SslError::StreamError(e))
+                    }
+                }
+                e => Err(e)
+            }
         }
     }
 
@@ -966,7 +979,17 @@ impl<S: Read+Write> SslStream<S> {
         if ret > 0 {
             Ok(stream)
         } else {
-            Err(stream.make_error(ret))
+            match stream.make_old_error(ret) {
+                SslError::StreamError(e) => {
+                    // This is fine - nonblocking sockets will finish the handshake in read/write
+                    if e.kind() == io::ErrorKind::WouldBlock {
+                        Ok(stream)
+                    } else {
+                        Err(SslError::StreamError(e))
+                    }
+                }
+                e => Err(e)
+            }
         }
     }
 
@@ -986,7 +1009,31 @@ impl<S: Read+Write> SslStream<S> {
 }
 
 impl<S> SslStream<S> {
-    fn make_error(&mut self, ret: c_int) -> SslError {
+    fn make_error(&mut self, ret: c_int) -> Error {
+        match self.ssl.get_error(ret) {
+            LibSslError::ErrorSsl => Error::Ssl(OpenSslError::get_stack()),
+            LibSslError::ErrorSyscall => {
+                let errs = OpenSslError::get_stack();
+                if errs.is_empty() {
+                    if ret == 0 {
+                        Error::Stream(io::Error::new(io::ErrorKind::ConnectionAborted,
+                                                     "unexpected EOF observed"))
+                    } else {
+                        Error::Stream(self.get_bio_error())
+                    }
+                } else {
+                    Error::Ssl(errs)
+                }
+            }
+            LibSslError::ErrorZeroReturn => Error::ZeroReturn,
+            LibSslError::ErrorWantWrite => Error::WantWrite(self.get_bio_error()),
+            LibSslError::ErrorWantRead => Error::WantRead(self.get_bio_error()),
+            err => Error::Stream(io::Error::new(io::ErrorKind::Other,
+                                                format!("unexpected error {:?}", err))),
+        }
+    }
+
+    fn make_old_error(&mut self, ret: c_int) -> SslError {
         match self.ssl.get_error(ret) {
             LibSslError::ErrorSsl => SslError::get(),
             LibSslError::ErrorSyscall => {
@@ -1045,6 +1092,32 @@ impl<S> SslStream<S> {
         }
     }
 
+    /// Like `read`, but returns an `ssl::Error` rather than an `io::Error`.
+    ///
+    /// This is particularly useful with a nonblocking socket, where the error
+    /// value will identify if OpenSSL is waiting on read or write readiness.
+    pub fn ssl_read(&mut self, buf: &mut [u8]) -> Result<usize, Error> {
+        let ret = self.ssl.read(buf);
+        if ret >= 0 {
+            Ok(ret as usize)
+        } else {
+            Err(self.make_error(ret))
+        }
+    }
+
+    /// Like `write`, but returns an `ssl::Error` rather than an `io::Error`.
+    ///
+    /// This is particularly useful with a nonblocking socket, where the error
+    /// value will identify if OpenSSL is waiting on read or write readiness.
+    pub fn ssl_write(&mut self, buf: &[u8]) -> Result<usize, Error> {
+        let ret = self.ssl.write(buf);
+        if ret >= 0 {
+            Ok(ret as usize)
+        } else {
+            Err(self.make_error(ret))
+        }
+    }
+
     /// Returns the OpenSSL `Ssl` object associated with this stream.
     pub fn ssl(&self) -> &Ssl {
         &self.ssl
@@ -1061,30 +1134,27 @@ impl SslStream<::std::net::TcpStream> {
 
 impl<S: Read> Read for SslStream<S> {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let ret = self.ssl.read(buf);
-        if ret >= 0 {
-            return Ok(ret as usize);
-        }
-
-        match self.make_error(ret) {
-            SslError::SslSessionClosed => Ok(0),
-            SslError::StreamError(e) => Err(e),
-            e => Err(io::Error::new(io::ErrorKind::Other, e)),
+        match self.ssl_read(buf) {
+            Ok(n) => Ok(n),
+            Err(Error::ZeroReturn) => Ok(0),
+            Err(Error::Stream(e)) => Err(e),
+            Err(Error::WantRead(e)) => Err(e),
+            Err(Error::WantWrite(e)) => Err(e),
+            Err(e) => Err(io::Error::new(io::ErrorKind::Other, e)),
         }
     }
 }
 
 impl<S: Write> Write for SslStream<S> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        let ret = self.ssl.write(buf);
-        if ret > 0 {
-            return Ok(ret as usize);
-        }
-
-        match self.make_error(ret) {
-            SslError::StreamError(e) => Err(e),
-            e => Err(io::Error::new(io::ErrorKind::Other, e)),
+        self.ssl_write(buf).map_err(|e| {
+            match e {
+                Error::Stream(e) => e,
+                Error::WantRead(e) => e,
+                Error::WantWrite(e) => e,
+                e => io::Error::new(io::ErrorKind::Other, e),
             }
+        })
     }
 
     fn flush(&mut self) -> io::Result<()> {
@@ -1174,7 +1244,9 @@ impl MaybeSslStream<net::TcpStream> {
     }
 }
 
-/// An SSL stream wrapping a nonblocking socket.
+/// # Deprecated
+///
+/// Use `SslStream` with `ssl_read` and `ssl_write`.
 #[derive(Clone)]
 pub struct NonblockingSslStream<S> {
     stream: S,