lzc: move lzc_ioctl_fd() into lzc proper

Name the OS-specific call lzc_ioctl_fd_os(), and make lzc_ioctl_fd()
wrap it, so we can do more in the wrapper.

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #17344

lib/libzfs_core/Makefile.am

@@ -1,18 +1,21 @@
 libzfs_core_la_CFLAGS  = $(AM_CFLAGS) $(LIBRARY_CFLAGS)
 libzfs_core_la_CFLAGS += -fvisibility=hidden
 
+libzfs_core_la_CPPFLAGS  = $(AM_CPPFLAGS)
+libzfs_core_la_CPPFLAGS += -I$(srcdir)/%D%
+
 lib_LTLIBRARIES += libzfs_core.la
 CPPCHECKTARGETS += libzfs_core.la
 
 libzfs_core_la_SOURCES = \
-	%D%/libzfs_core.c
+	%D%/libzfs_core.c \
+	%D%/libzfs_core_impl.h
 
 if BUILD_LINUX
 libzfs_core_la_SOURCES += \
 	%D%/os/linux/libzfs_core_ioctl.c
 endif
 
-libzfs_core_la_CPPFLAGS  = $(AM_CPPFLAGS)
 if BUILD_FREEBSD
 libzfs_core_la_CPPFLAGS += -Iinclude/os/freebsd/zfs
 

lib/libzfs_core/libzfs_core.c

@@ -96,6 +96,8 @@
 #define	BIG_PIPE_SIZE (64 * 1024) /* From sys/pipe.h */
 #endif
 
+#include "libzfs_core_impl.h"
+
 static int g_fd = -1;
 static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;
 static int g_refcount;
@@ -171,6 +173,12 @@ libzfs_core_fini(void)
 	(void) pthread_mutex_unlock(&g_lock);
 }
 
+int
+lzc_ioctl_fd(int fd, unsigned long ioc, zfs_cmd_t *zc)
+{
+	return (lzc_ioctl_fd_os(fd, ioc, zc));
+}
+
 static int
 lzc_ioctl(zfs_ioc_t ioc, const char *name,
     nvlist_t *source, nvlist_t **resultp)

lib/libzfs_core/libzfs_core_impl.h

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2012, 2020 by Delphix. All rights reserved.
+ * Copyright 2017 RackTop Systems.
+ * Copyright (c) 2017 Open-E, Inc. All Rights Reserved.
+ * Copyright (c) 2019 Datto Inc.
+ */
+
+#ifndef	_LIBZFS_CORE_IMPL_H
+#define	_LIBZFS_CORE_IMPL_H
+
+struct zfs_cmd;
+int lzc_ioctl_fd_os(int, unsigned long, struct zfs_cmd *);
+
+#endif	/* _LIBZFS_CORE_IMPL_H */

lib/libzfs_core/os/freebsd/libzfs_core_ioctl.c

@@ -26,6 +26,7 @@
 #include <os/freebsd/zfs/sys/zfs_ioctl_compat.h>
 #include <err.h>
 #include <libzfs_core.h>
+#include "libzfs_core_impl.h"
 
 int zfs_ioctl_version = ZFS_IOCVER_UNDEF;
 
@@ -101,7 +102,7 @@ zcmd_ioctl_compat(int fd, int request, zfs_cmd_t *zc, const int cflag)
  * error is returned zc_nvlist_dst_size won't be updated.
  */
 int
-lzc_ioctl_fd(int fd, unsigned long request, zfs_cmd_t *zc)
+lzc_ioctl_fd_os(int fd, unsigned long request, zfs_cmd_t *zc)
 {
 	size_t oldsize;
 	int ret, cflag = ZFS_CMD_COMPAT_NONE;

lib/libzfs_core/os/linux/libzfs_core_ioctl.c

@@ -23,9 +23,10 @@
 #include <sys/param.h>
 #include <sys/zfs_ioctl.h>
 #include <libzfs_core.h>
+#include "libzfs_core_impl.h"
 
 int
-lzc_ioctl_fd(int fd, unsigned long request, zfs_cmd_t *zc)
+lzc_ioctl_fd_os(int fd, unsigned long request, zfs_cmd_t *zc)
 {
 	return (ioctl(fd, request, zc));
 }