Fixed incorrect EOF handling in MemBio, added error description

Actually, EOF wasn't handled at all and it caused `mem_bio.read_to_end()` to fail. Which in turn failed all `write_pem` implementations.

src/bio/mod.rs

@@ -1,5 +1,5 @@
 use libc::{c_void, c_int};
-use std::io::{IoResult, IoError, OtherIoError};
+use std::io::{EndOfFile, IoResult, IoError, OtherIoError};
 use std::io::{Reader, Writer};
 use std::ptr;
 
@@ -62,9 +62,22 @@ impl Reader for MemBio {
                           buf.len() as c_int)
         };
 
-        if ret < 0 {
+        if ret <= 0 {
-            // FIXME: provide details from OpenSSL
+            let is_eof = unsafe { ffi::BIO_eof(self.bio) };
-            Err(IoError{kind: OtherIoError, desc: "mem bio read error", detail: None})
+            let err = if is_eof {
+                IoError {
+                    kind: EndOfFile,
+                    desc: "MemBio EOF",
+                    detail: None
+                }
+            } else {
+                IoError {
+                    kind: OtherIoError,
+                    desc: "MemBio read error",
+                    detail: Some(format!("{}", SslError::get()))
+                }
+            };
+            Err(err)
         } else {
             Ok(ret as uint)
         }
@@ -78,8 +91,11 @@ impl Writer for MemBio {
                            buf.len() as c_int)
         };
         if buf.len() != ret as uint {
-            // FIXME: provide details from OpenSSL
+            Err(IoError {
-            Err(IoError{kind: OtherIoError, desc: "mem bio write error", detail: None})
+                kind: OtherIoError,
+                desc: "MemBio write error",
+                detail: Some(format!("{}", SslError::get()))
+            })
         } else {
             Ok(())
         }

src/ffi.rs

@@ -1,6 +1,7 @@
 #![allow(non_camel_case_types, non_uppercase_statics, non_snake_case)]
 #![allow(dead_code)]
 use libc::{c_void, c_int, c_char, c_ulong, c_long, c_uint, c_uchar, size_t};
+use std::ptr;
 
 pub type ASN1_INTEGER = c_void;
 pub type ASN1_STRING = c_void;
@@ -84,6 +85,8 @@ pub type PrivateKeyWriteCallback = extern "C" fn(buf: *mut c_char, size: c_int,
                                                  rwflag: c_int, user_data: *mut c_void)
                                                  -> c_int;
 
+pub static BIO_CTRL_EOF: c_int = 2;
+
 pub static CRYPTO_LOCK: c_int = 1;
 
 pub static MBSTRING_ASC:  c_int = MBSTRING_FLAG | 1;
@@ -195,12 +198,19 @@ extern "C" {
     pub fn bn_is_zero(a: *mut BIGNUM) -> c_int;
 }
 
+// Functions converted from macros
+pub unsafe fn BIO_eof(b: *mut BIO) -> bool {
+    BIO_ctrl(b, BIO_CTRL_EOF, 0, ptr::null_mut()) == 1
+}
+
+// True functions
 extern "C" {
     pub fn ASN1_INTEGER_set(dest: *mut ASN1_INTEGER, value: c_long) -> c_int;
     pub fn ASN1_STRING_type_new(ty: c_int) -> *mut ASN1_STRING;
     pub fn ASN1_TIME_free(tm: *mut ASN1_TIME);
 
-    pub fn BIO_free_all(a: *mut BIO);
+    pub fn BIO_ctrl(b: *mut BIO, cmd: c_int, larg: c_long, parg: *mut c_void) -> c_long;
+    pub fn BIO_free_all(b: *mut BIO);
     pub fn BIO_new(type_: *const BIO_METHOD) -> *mut BIO;
     pub fn BIO_read(b: *mut BIO, buf: *mut c_void, len: c_int) -> c_int;
     pub fn BIO_write(b: *mut BIO, buf: *const c_void, len: c_int) -> c_int;

src/ssl/tests.rs

@@ -1,4 +1,4 @@
-use std::io::Writer;
+use std::io::{File, Open, Write, Writer};
 use std::io::net::tcp::TcpStream;
 use std::num::FromStrRadix;
 use std::str;
@@ -218,6 +218,22 @@ fn test_cert_gen() {
 
     let res = gen.generate();
     assert!(res.is_ok());
+
+    let (cert, pkey) = res.unwrap();
+
+    #[cfg(unix)]
+    static NULL_PATH: &'static str = "/dev/null";
+    #[cfg(windows)]
+    static NULL_PATH: &'static str = "nul";
+
+    let cert_path = Path::new(NULL_PATH);
+    let mut file = File::open_mode(&cert_path, Open, Write).unwrap();
+    assert!(cert.write_pem(&mut file).is_ok());
+
+    let key_path = Path::new(NULL_PATH);
+    let mut file = File::open_mode(&key_path, Open, Write).unwrap();
+    assert!(pkey.write_pem(&mut file).is_ok());
+
     // FIXME: check data in result to be correct, needs implementation
     // of X509 getters
 }