From b86f08e9d6f083d20c81054e2fff0d54695a4a2e Mon Sep 17 00:00:00 2001
From: Howard Chu <hyc@symas.com>
Date: Mon, 21 Oct 2013 10:29:38 -0700
Subject: [PATCH] Add mdb_env_get_fd()

Return the environment's filedescriptor. Useful when the caller
is doing their own locking.
---
 libraries/liblmdb/lmdb.h | 12 ++++++++++++
 libraries/liblmdb/mdb.c  | 10 ++++++++++
 2 files changed, 22 insertions(+)

diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index f72869e..f6d0a0a 100644
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -679,6 +679,18 @@ int  mdb_env_get_flags(MDB_env *env, unsigned int *flags);
 	 */
 int  mdb_env_get_path(MDB_env *env, const char **path);
 
+	/** @brief Return the filedescriptor for the given environment.
+	 *
+	 * @param[in] env An environment handle returned by #mdb_env_create()
+	 * @param[out] fd Address of a mdb_filehandle_t to contain the descriptor.
+	 * @return A non-zero error value on failure and 0 on success. Some possible
+	 * errors are:
+	 * <ul>
+	 *	<li>EINVAL - an invalid parameter was specified.
+	 * </ul>
+	 */
+int  mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *fd);
+
 	/** @brief Set the size of the memory map to use for this environment.
 	 *
 	 * The size should be a multiple of the OS page size. The default is
diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index e52da91..33be876 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -7817,6 +7817,16 @@ mdb_env_get_path(MDB_env *env, const char **arg)
 	return MDB_SUCCESS;
 }
 
+int
+mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *arg)
+{
+	if (!env || !arg)
+		return EINVAL;
+
+	*arg = env->me_fd;
+	return MDB_SUCCESS;
+}
+
 /** Common code for #mdb_stat() and #mdb_env_stat().
  * @param[in] env the environment to operate in.
  * @param[in] db the #MDB_db record containing the stats to return.