Tweak nbdkit-1.22.0 for CDI build

nbdkit.go

@@ -0,0 +1,569 @@
+/* Go helper functions.
+ * Copyright (C) 2013-2020 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+package nbdkit
+
+/*
+#cgo LDFLAGS: -lnbdkit
+#cgo LDFLAGS: -Wl,--unresolved-symbols=ignore-in-object-files
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#define NBDKIT_API_VERSION 2
+#include <nbdkit-plugin.h>
+#include "wrappers.h"
+*/
+import "C"
+
+import (
+	"fmt"
+	"reflect"
+	"syscall"
+	"unsafe"
+)
+
+// The plugin may raise errors by returning this struct (instead of nil).
+type PluginError struct {
+	Errmsg string        // string (passed to nbdkit_error)
+	Errno  syscall.Errno // errno (optional, use 0 if not available)
+}
+
+func (e PluginError) String() string {
+	if e.Errno != 0 {
+		return e.Errmsg
+	} else {
+		return fmt.Sprintf("%s (errno %d)", e.Errmsg, e.Errno)
+	}
+}
+
+func (e PluginError) Error() string {
+	return e.String()
+}
+
+// Flags and other constants.
+const (
+	ThreadModelSerializeConnections = uint32(C.NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS)
+	ThreadModelSerializeAllRequests = uint32(C.NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS)
+	ThreadModelSerializeRequests    = uint32(C.NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS)
+	ThreadModelParallel             = uint32(C.NBDKIT_THREAD_MODEL_PARALLEL)
+
+	FlagMayTrim  = uint32(C.NBDKIT_FLAG_MAY_TRIM)
+	FlagFUA      = uint32(C.NBDKIT_FLAG_FUA)
+	FlagReqOne   = uint32(C.NBDKIT_FLAG_REQ_ONE)
+	FlagFastZero = uint32(C.NBDKIT_FLAG_FAST_ZERO)
+
+	FUANone    = uint32(C.NBDKIT_FUA_NONE)
+	FUAEmulate = uint32(C.NBDKIT_FUA_EMULATE)
+	FUANative  = uint32(C.NBDKIT_FUA_NATIVE)
+
+	CacheNone    = uint32(C.NBDKIT_CACHE_NONE)
+	CacheEmulate = uint32(C.NBDKIT_CACHE_EMULATE)
+	CacheNative  = uint32(C.NBDKIT_CACHE_NATIVE)
+
+	ExtentHole = uint32(C.NBDKIT_EXTENT_HOLE)
+	ExtentZero = uint32(C.NBDKIT_EXTENT_ZERO)
+
+	// This is not defined by the header, but by this file.  It
+	// might be useful for plugins to know this (even though they
+	// probably wouldn't be source-compatible with other API
+	// versions) so we expose it to golang code.
+	APIVersion = uint32(C.NBDKIT_API_VERSION)
+)
+
+// The plugin interface.
+type PluginInterface interface {
+	Load()
+	Unload()
+
+	DumpPlugin()
+
+	Config(key string, value string) error
+	ConfigComplete() error
+	GetReady() error
+
+	PreConnect(readonly bool) error
+	Open(readonly bool) (ConnectionInterface, error) // required
+}
+
+// The client connection interface.
+type ConnectionInterface interface {
+	GetSize() (uint64, error) // required
+	IsRotational() (bool, error)
+	CanMultiConn() (bool, error)
+
+	PRead(buf []byte, offset uint64, flags uint32) error // required
+
+	// NB: PWrite will NOT be called unless CanWrite returns true.
+	CanWrite() (bool, error)
+	PWrite(buf []byte, offset uint64, flags uint32) error
+
+	// NB: Flush will NOT be called unless CanFlush returns true.
+	CanFlush() (bool, error)
+	Flush(flags uint32) error
+
+	// NB: Trim will NOT be called unless CanTrim returns true.
+	CanTrim() (bool, error)
+	Trim(count uint32, offset uint64, flags uint32) error
+
+	// NB: Zero will NOT be called unless CanZero returns true.
+	CanZero() (bool, error)
+	Zero(count uint32, offset uint64, flags uint32) error
+
+	Close()
+}
+
+// Default implementations for plugin interface methods.
+type Plugin struct{}
+type Connection struct{}
+
+func (p *Plugin) Load() {
+}
+
+func (p *Plugin) Unload() {
+}
+
+func (p *Plugin) DumpPlugin() {
+}
+
+func (p *Plugin) Config(key string, value string) error {
+	return nil
+}
+
+func (p *Plugin) ConfigComplete() error {
+	return nil
+}
+
+func (p *Plugin) GetReady() error {
+	return nil
+}
+
+func (p *Plugin) PreConnect(readonly bool) error {
+	return nil
+}
+
+func (p *Plugin) Open(readonly bool) (ConnectionInterface, error) {
+	panic("plugin must implement Open()")
+}
+
+func (c *Connection) Close() {
+}
+
+func (c *Connection) GetSize() (uint64, error) {
+	panic("plugin must implement GetSize()")
+}
+
+func (c *Connection) CanWrite() (bool, error) {
+	return false, nil
+}
+
+func (c *Connection) CanFlush() (bool, error) {
+	return false, nil
+}
+
+func (c *Connection) IsRotational() (bool, error) {
+	return false, nil
+}
+
+func (c *Connection) CanTrim() (bool, error) {
+	return false, nil
+}
+
+func (c *Connection) CanZero() (bool, error) {
+	return false, nil
+}
+
+func (c *Connection) CanMultiConn() (bool, error) {
+	return false, nil
+}
+
+func (c *Connection) PRead(buf []byte, offset uint64, flags uint32) error {
+	panic("plugin must implement PRead()")
+}
+
+func (c *Connection) PWrite(buf []byte, offset uint64, flags uint32) error {
+	panic("plugin CanWrite returns true, but no PWrite() function")
+}
+
+func (c *Connection) Flush(flags uint32) error {
+	panic("plugin CanFlush returns true, but no Flush() function")
+}
+
+func (c *Connection) Trim(count uint32, offset uint64, flags uint32) error {
+	panic("plugin CanTrim returns true, but no Trim() function")
+}
+
+func (c *Connection) Zero(count uint32, offset uint64, flags uint32) error {
+	panic("plugin CanZero returns true, but no Zero() function")
+}
+
+// The implementation of the user plugin.
+var pluginImpl PluginInterface
+var nextConnectionId uintptr
+var connectionMap map[uintptr]ConnectionInterface
+
+// Callbacks from the server.  These translate C to Go and back.
+
+func set_error(err error) {
+	perr, ok := err.(PluginError)
+	if ok {
+		if perr.Errno != 0 {
+			SetError(perr.Errno)
+		}
+		Error(perr.Errmsg)
+	} else {
+		Error(err.Error())
+	}
+}
+
+//export implLoad
+func implLoad() {
+	pluginImpl.Load()
+}
+
+//export implUnload
+func implUnload() {
+	pluginImpl.Unload()
+}
+
+//export implDumpPlugin
+func implDumpPlugin() {
+	pluginImpl.DumpPlugin()
+}
+
+//export implConfig
+func implConfig(key *C.char, value *C.char) C.int {
+	err := pluginImpl.Config(C.GoString(key), C.GoString(value))
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implConfigComplete
+func implConfigComplete() C.int {
+	err := pluginImpl.ConfigComplete()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implGetReady
+func implGetReady() C.int {
+	err := pluginImpl.GetReady()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implPreConnect
+func implPreConnect(c_readonly C.int) C.int {
+	readonly := false
+	if c_readonly != 0 {
+		readonly = true
+	}
+	err := pluginImpl.PreConnect(readonly)
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implOpen
+func implOpen(c_readonly C.int) unsafe.Pointer {
+	readonly := false
+	if c_readonly != 0 {
+		readonly = true
+	}
+	h, err := pluginImpl.Open(readonly)
+	if err != nil {
+		set_error(err)
+		return nil
+	}
+	id := nextConnectionId
+	nextConnectionId++
+	connectionMap[id] = h
+	return unsafe.Pointer(id)
+}
+
+func getConn(handle unsafe.Pointer) ConnectionInterface {
+	id := uintptr(handle)
+	h, ok := connectionMap[id]
+	if !ok {
+		panic(fmt.Sprintf("connection %d was not open", id))
+	}
+	return h
+}
+
+//export implClose
+func implClose(handle unsafe.Pointer) {
+	h := getConn(handle)
+	h.Close()
+	id := uintptr(handle)
+	delete(connectionMap, id)
+}
+
+//export implGetSize
+func implGetSize(handle unsafe.Pointer) C.int64_t {
+	h := getConn(handle)
+	size, err := h.GetSize()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return C.int64_t(size)
+}
+
+//export implCanWrite
+func implCanWrite(handle unsafe.Pointer) C.int {
+	h := getConn(handle)
+	b, err := h.CanWrite()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+//export implCanFlush
+func implCanFlush(handle unsafe.Pointer) C.int {
+	h := getConn(handle)
+	b, err := h.CanFlush()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+//export implIsRotational
+func implIsRotational(handle unsafe.Pointer) C.int {
+	h := getConn(handle)
+	b, err := h.IsRotational()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+//export implCanTrim
+func implCanTrim(handle unsafe.Pointer) C.int {
+	h := getConn(handle)
+	b, err := h.CanTrim()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+//export implCanZero
+func implCanZero(handle unsafe.Pointer) C.int {
+	h := getConn(handle)
+	b, err := h.CanZero()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+//export implCanMultiConn
+func implCanMultiConn(handle unsafe.Pointer) C.int {
+	h := getConn(handle)
+	b, err := h.CanMultiConn()
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+//export implPRead
+func implPRead(handle unsafe.Pointer, c_buf unsafe.Pointer,
+	count C.uint32_t, offset C.uint64_t, flags C.uint32_t) C.int {
+	h := getConn(handle)
+	// https://github.com/golang/go/issues/13656
+	// https://stackoverflow.com/a/25776046
+	hdr := reflect.SliceHeader{
+		Data: uintptr(c_buf),
+		Len:  int(count),
+		Cap:  int(count),
+	}
+	buf := *(*[]byte)(unsafe.Pointer(&hdr))
+	err := h.PRead(buf, uint64(offset), uint32(flags))
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implPWrite
+func implPWrite(handle unsafe.Pointer, c_buf unsafe.Pointer,
+	count C.uint32_t, offset C.uint64_t, flags C.uint32_t) C.int {
+	h := getConn(handle)
+	// https://github.com/golang/go/issues/13656
+	// https://stackoverflow.com/a/25776046
+	hdr := reflect.SliceHeader{
+		Data: uintptr(c_buf),
+		Len:  int(count),
+		Cap:  int(count),
+	}
+	buf := *(*[]byte)(unsafe.Pointer(&hdr))
+	err := h.PWrite(buf, uint64(offset), uint32(flags))
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implFlush
+func implFlush(handle unsafe.Pointer, flags C.uint32_t) C.int {
+	h := getConn(handle)
+	err := h.Flush(uint32(flags))
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implTrim
+func implTrim(handle unsafe.Pointer,
+	count C.uint32_t, offset C.uint64_t, flags C.uint32_t) C.int {
+	h := getConn(handle)
+	err := h.Trim(uint32(count), uint64(offset), uint32(flags))
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+//export implZero
+func implZero(handle unsafe.Pointer,
+	count C.uint32_t, offset C.uint64_t, flags C.uint32_t) C.int {
+	h := getConn(handle)
+	err := h.Zero(uint32(count), uint64(offset), uint32(flags))
+	if err != nil {
+		set_error(err)
+		return -1
+	}
+	return 0
+}
+
+// Called from C plugin_init function.
+func PluginInitialize(name string, impl PluginInterface) unsafe.Pointer {
+	// Initialize the connection map.  Note that connection IDs
+	// must start counting from 1 since we must never return what
+	// looks like a NULL pointer to the C code.
+	connectionMap = make(map[uintptr]ConnectionInterface)
+	nextConnectionId = 1
+
+	pluginImpl = impl
+
+	plugin := C.struct_nbdkit_plugin{}
+
+	// Set up the hidden plugin fields as for C.
+	struct_size := C.ulong(unsafe.Sizeof(plugin))
+	plugin._struct_size = struct_size
+	plugin._api_version = C.NBDKIT_API_VERSION
+	plugin._thread_model = C.NBDKIT_THREAD_MODEL_PARALLEL
+
+	// Set up the other fields.
+	plugin.name = C.CString(name)
+	plugin.load = (*[0]byte)(C.wrapper_load)
+	plugin.unload = (*[0]byte)(C.wrapper_unload)
+	plugin.dump_plugin = (*[0]byte)(C.wrapper_dump_plugin)
+	plugin.config = (*[0]byte)(C.wrapper_config)
+	plugin.config_complete = (*[0]byte)(C.wrapper_config_complete)
+	plugin.get_ready = (*[0]byte)(C.wrapper_get_ready)
+	plugin.preconnect = (*[0]byte)(C.wrapper_preconnect)
+	plugin.open = (*[0]byte)(C.wrapper_open)
+	plugin.close = (*[0]byte)(C.wrapper_close)
+	plugin.get_size = (*[0]byte)(C.wrapper_get_size)
+	plugin.can_write = (*[0]byte)(C.wrapper_can_write)
+	plugin.can_flush = (*[0]byte)(C.wrapper_can_flush)
+	plugin.is_rotational = (*[0]byte)(C.wrapper_is_rotational)
+	plugin.can_trim = (*[0]byte)(C.wrapper_can_trim)
+	plugin.can_zero = (*[0]byte)(C.wrapper_can_zero)
+	plugin.can_multi_conn = (*[0]byte)(C.wrapper_can_multi_conn)
+	plugin.pread = (*[0]byte)(C.wrapper_pread)
+	plugin.pwrite = (*[0]byte)(C.wrapper_pwrite)
+	plugin.flush = (*[0]byte)(C.wrapper_flush)
+	plugin.trim = (*[0]byte)(C.wrapper_trim)
+	plugin.zero = (*[0]byte)(C.wrapper_zero)
+
+	// Golang plugins don't preserve errno correctly.
+	plugin.errno_is_preserved = 0
+
+	// Return a newly malloced copy of the struct.  This must be
+	// globally available to the C code in the server, so it is
+	// never freed.
+	p := (*C.struct_nbdkit_plugin)(C.malloc(struct_size))
+	*p = plugin
+	return unsafe.Pointer(p)
+}

utils.go

@@ -0,0 +1,75 @@
+/* cgo wrappers.
+ * Copyright (C) 2013-2020 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+package nbdkit
+
+/*
+#cgo LDFLAGS: -lnbdkit
+
+#define NBDKIT_API_VERSION 2
+#include <nbdkit-plugin.h>
+
+// cgo cannot call varargs functions.
+void
+_nbdkit_debug (const char *s)
+{
+  nbdkit_debug ("%s", s);
+}
+
+// cgo cannot call varargs functions.
+void
+_nbdkit_error (const char *s)
+{
+  nbdkit_error ("%s", s);
+}
+*/
+import "C"
+import "syscall"
+
+// Utility functions.
+
+func Debug(s string) {
+	C._nbdkit_debug(C.CString(s))
+}
+
+// This function is provided but plugins would rarely need to call
+// this explicitly since returning an error from a plugin callback
+// will call it implicitly.
+func Error(s string) {
+	C._nbdkit_error(C.CString(s))
+}
+
+// Same applies as for Error().  Callers should not usually need to
+// call this.
+func SetError(err syscall.Errno) {
+	C.nbdkit_set_error(C.int(err))
+}

wrappers.go

@@ -0,0 +1,196 @@
+/* cgo wrappers.
+ * Copyright (C) 2013-2020 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+package nbdkit
+
+/*
+#cgo LDFLAGS: -lnbdkit
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define NBDKIT_API_VERSION 2
+#include <nbdkit-plugin.h>
+#include "wrappers.h"
+
+extern void implLoad ();
+void
+wrapper_load (void)
+{
+  implLoad ();
+}
+
+extern void implUnload ();
+void
+wrapper_unload (void)
+{
+  implUnload ();
+}
+
+extern void implDumpPlugin ();
+void
+wrapper_dump_plugin (void)
+{
+  implDumpPlugin ();
+}
+
+extern int implConfig ();
+int
+wrapper_config (const char *key, const char *value)
+{
+  return implConfig (key, value);
+}
+
+extern int implConfigComplete ();
+int
+wrapper_config_complete (void)
+{
+  return implConfigComplete ();
+}
+
+extern int implGetReady ();
+int
+wrapper_get_ready (void)
+{
+  return implGetReady ();
+}
+
+extern int implPreConnect ();
+int
+wrapper_preconnect (int readonly)
+{
+  return implPreConnect (readonly);
+}
+
+extern void *implOpen ();
+void *
+wrapper_open (int readonly)
+{
+  return implOpen (readonly);
+}
+
+extern void implClose ();
+void
+wrapper_close (void *handle)
+{
+  return implClose (handle);
+}
+
+extern int64_t implGetSize ();
+int64_t
+wrapper_get_size (void *handle)
+{
+  return implGetSize (handle);
+}
+
+extern int implCanWrite ();
+int
+wrapper_can_write (void *handle)
+{
+  return implCanWrite (handle);
+}
+
+extern int implCanFlush ();
+int
+wrapper_can_flush (void *handle)
+{
+  return implCanFlush (handle);
+}
+
+extern int implIsRotational ();
+int
+wrapper_is_rotational (void *handle)
+{
+  return implIsRotational (handle);
+}
+
+extern int implCanTrim ();
+int
+wrapper_can_trim (void *handle)
+{
+  return implCanTrim (handle);
+}
+
+extern int implCanZero ();
+int
+wrapper_can_zero (void *handle)
+{
+  return implCanZero (handle);
+}
+
+extern int implCanMultiConn ();
+int
+wrapper_can_multi_conn (void *handle)
+{
+  return implCanMultiConn (handle);
+}
+
+extern int implPRead ();
+int
+wrapper_pread (void *handle, void *buf,
+               uint32_t count, uint64_t offset, uint32_t flags)
+{
+  return implPRead (handle, buf, count, offset, flags);
+}
+
+extern int implPWrite ();
+int
+wrapper_pwrite (void *handle, const void *buf,
+                uint32_t count, uint64_t offset, uint32_t flags)
+{
+  return implPWrite (handle, buf, count, offset, flags);
+}
+
+extern int implFlush ();
+int
+wrapper_flush (void *handle, uint32_t flags)
+{
+  return implFlush (handle, flags);
+}
+
+extern int implTrim ();
+int
+wrapper_trim (void *handle,
+              uint32_t count, uint64_t offset, uint32_t flags)
+{
+  return implTrim (handle, count, offset, flags);
+}
+
+extern int implZero ();
+int
+wrapper_zero (void *handle,
+              uint32_t count, uint64_t offset, uint32_t flags)
+{
+  return implZero (handle, count, offset, flags);
+}
+*/
+import "C"

wrappers.h

@@ -0,0 +1,57 @@
+/* cgo wrappers.
+ * Copyright (C) 2013-2020 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+extern void    wrapper_load ();
+extern void    wrapper_unload ();
+extern void    wrapper_dump_plugin ();
+extern int     wrapper_config (const char *key, const char *value);
+extern int     wrapper_config_complete (void);
+extern int     wrapper_get_ready (void);
+extern int     wrapper_preconnect (int readonly);
+extern void *  wrapper_open (int readonly);
+extern void    wrapper_close (void *handle);
+extern int64_t wrapper_get_size (void *handle);
+extern int     wrapper_can_write (void *handle);
+extern int     wrapper_can_flush (void *handle);
+extern int     wrapper_is_rotational (void *handle);
+extern int     wrapper_can_trim (void *handle);
+extern int     wrapper_can_zero (void *handle);
+extern int     wrapper_can_multi_conn (void *handle);
+extern int     wrapper_pread (void *handle, void *buf,
+                              uint32_t count, uint64_t offset, uint32_t flags);
+extern int     wrapper_pwrite (void *handle, const void *buf,
+                               uint32_t count, uint64_t offset, uint32_t flags);
+extern int     wrapper_flush (void *handle, uint32_t flags);
+extern int     wrapper_trim (void *handle,
+                             uint32_t count, uint64_t offset, uint32_t flags);
+extern int     wrapper_zero (void *handle,
+                             uint32_t count, uint64_t offset, uint32_t flags);