Make password callback return a Result

openssl/src/dsa.rs

@@ -237,7 +237,7 @@ mod test {
         Dsa::private_key_from_pem_callback(key, |password| {
                 password_queried = true;
                 password[..6].copy_from_slice(b"mypass");
-                6
+                Ok(6)
             })
             .unwrap();
 

openssl/src/macros.rs

@@ -81,7 +81,7 @@ macro_rules! private_key_from_pem {
         pub fn private_key_from_pem_callback<F>(pem: &[u8],
                                                 callback: F)
                                                 -> Result<$t, ::error::ErrorStack>
-            where F: FnOnce(&mut [u8]) -> usize
+            where F: FnOnce(&mut [u8]) -> Result<usize, ::error::ErrorStack>
         {
             unsafe {
                 ffi::init();

openssl/src/rsa.rs

@@ -421,7 +421,7 @@ mod test {
         Rsa::private_key_from_pem_callback(key, |password| {
                 password_queried = true;
                 password[..6].copy_from_slice(b"mypass");
-                6
+                Ok(6)
             })
             .unwrap();
 

openssl/src/util.rs

@@ -4,6 +4,8 @@ use std::cell::UnsafeCell;
 use std::panic::{self, AssertUnwindSafe};
 use std::slice;
 
+use error::ErrorStack;
+
 /// Wraps a user-supplied callback and a slot for panics thrown inside the callback (while FFI
 /// frames are on the stack).
 ///
@@ -64,7 +66,7 @@ pub unsafe extern fn invoke_passwd_cb<F>(buf: *mut c_char,
                                          _rwflag: c_int,
                                          cb_state: *mut c_void)
                                          -> c_int
-    where F: FnOnce(&mut [u8]) -> usize
+    where F: FnOnce(&mut [u8]) -> Result<usize, ErrorStack>
 {
     let callback = &mut *(cb_state as *mut CallbackState<F>);
 
@@ -74,7 +76,11 @@ pub unsafe extern fn invoke_passwd_cb<F>(buf: *mut c_char,
     }));
 
     match result {
-        Ok(len) => len as c_int,
+        Ok(Ok(len)) => len as c_int,
+        Ok(Err(_)) => {
+            // FIXME restore error stack
+            0
+        }
         Err(err) => {
             callback.panic = Some(err);
             0