RTCCertificate serialization.

webrtc/base/opensslidentity.cc

Index: webrtc/base/opensslidentity.cc
diff --git a/webrtc/base/opensslidentity.cc b/webrtc/base/opensslidentity.cc
index 9c2112e157c0dc71099b57a764c58c4e48d4c28b..d86974569c40f58948a811e840871d410cc9f3ad 100644
--- a/webrtc/base/opensslidentity.cc
+++ b/webrtc/base/opensslidentity.cc
@@ -181,6 +181,28 @@ void OpenSSLKeyPair::AddReference() {
 #endif
 }
 
+std::string OpenSSLKeyPair::PrivateKeyToPemString() const {
+  BIO* temp_memory_bio = BIO_new(BIO_s_mem());
+  if (!temp_memory_bio) {
+    LOG_F(LS_ERROR) << "Failed to allocate temporary memory bio";
+    RTC_NOTREACHED();
+    return "";
+  }
+  if (!PEM_write_bio_PrivateKey(
+      temp_memory_bio, pkey_, nullptr, nullptr, 0, nullptr, nullptr)) {
+    LOG_F(LS_ERROR) << "Failed to read private key";
+    BIO_free(temp_memory_bio);
+    RTC_NOTREACHED();
+    return "";
+  }
+  BIO_write(temp_memory_bio, "\0", 1);
+  char* buffer;
+  BIO_get_mem_data(temp_memory_bio, &buffer);
+  std::string priv_key_str = buffer;
+  BIO_free(temp_memory_bio);
+  return priv_key_str;
+}
+
 #if !defined(NDEBUG)
 // Print a certificate to the log, for debugging.
 static void PrintCert(X509* x509) {
@@ -475,6 +497,10 @@ bool OpenSSLIdentity::ConfigureIdentity(SSL_CTX* ctx) {
   return true;
 }
 
+std::string OpenSSLIdentity::PrivateKeyToPemString() const {
+  return key_pair_->PrivateKeyToPemString();
+}
+
 }  // namespace rtc
 
 #endif  // HAVE_OPENSSL_SSL_H