sasl_gssapi: Made log_gss_error() a common GSS-API function

Made log_gss_error() a common function so that it can be used in both
the http_negotiate code as well as the curl_sasl_gssapi code.

lib/curl_gssapi.c

@@ -72,4 +72,45 @@ OM_uint32 Curl_gss_init_sec_context(
                               NULL /* time_rec */);
 }
 
+/*
+ * Curl_gss_log_error()
+ *
+ * This is used to log a GSS-API error status.
+ *
+ * Parameters:
+ *
+ * data    [in] - The session handle.
+ * status  [in] - The status code.
+ * prefix  [in] - The prefix of the log message.
+ */
+void Curl_gss_log_error(struct SessionHandle *data, OM_uint32 status,
+                        const char *prefix)
+{
+  OM_uint32 maj_stat;
+  OM_uint32 min_stat;
+  OM_uint32 msg_ctx = 0;
+  gss_buffer_desc status_string;
+  char buf[1024];
+  size_t len;
+
+  snprintf(buf, sizeof(buf), "%s", prefix);
+  len = strlen(buf);
+  do {
+    maj_stat = gss_display_status(&min_stat,
+                                  status,
+                                  GSS_C_MECH_CODE,
+                                  GSS_C_NO_OID,
+                                  &msg_ctx,
+                                  &status_string);
+    if(sizeof(buf) > len + status_string.length + 1) {
+      snprintf(buf + len, sizeof(buf) - len,
+        ": %s", (char*)status_string.value);
+      len += status_string.length;
+    }
+    gss_release_buffer(&min_stat, &status_string);
+  } while(!GSS_ERROR(maj_stat) && msg_ctx != 0);
+
+  infof(data, "%s\n", buf);
+}
+
 #endif /* HAVE_GSSAPI */