From 6d2f8d67f2423ba6a337359ecf0188bd52227dce Mon Sep 17 00:00:00 2001
From: Ummon <greg.burri@gmail.com>
Date: Wed, 10 Dec 2014 22:25:32 +0100
Subject: [PATCH] Add the openssl function prototype 'HMAC_CTX_cleanup'.

---
 openssl-sys/src/lib.rs | 1 +
 src/crypto/hmac.rs     | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/openssl-sys/src/lib.rs b/openssl-sys/src/lib.rs
index 0644a674..1faf749e 100644
--- a/openssl-sys/src/lib.rs
+++ b/openssl-sys/src/lib.rs
@@ -361,6 +361,7 @@ extern "C" {
     pub fn HMAC_Init_ex(ctx: *mut HMAC_CTX, key: *const u8, keylen: c_int, md: *const EVP_MD, imple: *const ENGINE);
     pub fn HMAC_Final(ctx: *mut HMAC_CTX, output: *mut u8, len: *mut c_uint);
     pub fn HMAC_Update(ctx: *mut HMAC_CTX, input: *const u8, len: c_uint);
+    pub fn HMAC_CTX_cleanup(ctx: *mut HMAC_CTX);
 
 
     pub fn PEM_read_bio_X509(bio: *mut BIO, out: *mut *mut X509, callback: Option<PasswordCallback>,
diff --git a/src/crypto/hmac.rs b/src/crypto/hmac.rs
index a7a854b7..8096a948 100644
--- a/src/crypto/hmac.rs
+++ b/src/crypto/hmac.rs
@@ -61,6 +61,14 @@ impl HMAC {
     }
 }
 
+impl Drop for HMAC {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::HMAC_CTX_cleanup(&mut self.ctx);
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use serialize::hex::FromHex;