From 390d71f1e546aa33b0ef34bf93e2a0f4327b978e Mon Sep 17 00:00:00 2001
From: Mike Belopuhov <mike@belopuhov.com>
Date: Thu, 13 Jun 2019 02:55:15 +0200
Subject: [PATCH] Expose EC_GROUP_get0_generator as EcGroup::generator

---
 openssl-sys/src/ec.rs |  2 ++
 openssl/src/ec.rs     | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/openssl-sys/src/ec.rs b/openssl-sys/src/ec.rs
index ca4c09ea..05faee27 100644
--- a/openssl-sys/src/ec.rs
+++ b/openssl-sys/src/ec.rs
@@ -30,6 +30,8 @@ extern "C" {
         ctx: *mut BN_CTX,
     ) -> c_int;
 
+    pub fn EC_GROUP_get0_generator(group: *const EC_GROUP) -> *const EC_POINT;
+
     pub fn EC_GROUP_get_curve_name(group: *const EC_GROUP) -> c_int;
 
     pub fn EC_GROUP_set_asn1_flag(key: *mut EC_GROUP, flag: c_int);
diff --git a/openssl/src/ec.rs b/openssl/src/ec.rs
index c65dd441..34b7f05e 100644
--- a/openssl/src/ec.rs
+++ b/openssl/src/ec.rs
@@ -208,6 +208,18 @@ impl EcGroupRef {
         unsafe { ffi::EC_GROUP_get_degree(self.as_ptr()) as u32 }
     }
 
+    /// Returns the generator for the given curve as a [`EcPoint`].
+    ///
+    /// OpenSSL documentation at [`EC_GROUP_get0_generator`]
+    ///
+    /// [`EC_GROUP_get0_generator`]: https://www.openssl.org/docs/man1.1.0/man3/EC_GROUP_get0_generator.html
+    pub fn generator(&self) -> &EcPointRef {
+        unsafe {
+            let ptr = ffi::EC_GROUP_get0_generator(self.as_ptr());
+            EcPointRef::from_ptr(ptr as *mut _)
+        }
+    }
+
     /// Places the order of the curve in the provided `BigNum`.
     ///
     /// OpenSSL documentation at [`EC_GROUP_get_order`]
@@ -889,6 +901,17 @@ mod test {
         assert!(public_key.eq(&group, key.public_key(), &mut ctx).unwrap());
     }
 
+    #[test]
+    fn generator() {
+        let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap();
+        let gen = group.generator();
+        let one = BigNum::from_u32(1).unwrap();
+        let mut ctx = BigNumContext::new().unwrap();
+        let mut ecp = EcPoint::new(&group).unwrap();
+        ecp.mul_generator(&group, &one, &mut ctx).unwrap();
+        assert!(ecp.eq(&group, gen, &mut ctx).unwrap());
+    }
+
     #[test]
     fn key_from_public_key() {
         let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap();