VMware vSphere Driver

This patch introduces the new VMware vSphere VMDK Driver - "vmdk".
The driver uses VMCI Sockets
(https://www.vmware.com/support/developer/vmci-sdk/)
to communicate directly with a vSphere host, removing the need
for the sizeable VMware SDK for Go library dependency.

.gitignore

@@ -7,6 +7,7 @@
 *.d
 *.out
 got
+gob
 libstorage.paw
 .site/
 site/

drivers/storage/vmw/vmci/connection_types.h

@@ -0,0 +1,63 @@
+// Copyright 2016 VMware, Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Shared info (magic, err. codes, etc) on vSocket command channel
+
+#ifndef _CONNECTION_TYPES_H_
+#define _CONNECTION_TYPES_H_
+
+#define MAGIC 0xbadbeef
+
+// -1 always indicates failure
+#define CONN_FAILURE (-1)
+
+// 0 is usually success. Note: sometimes we return socket FD on success
+#define CONN_SUCCESS  (0)
+
+// First non privileged port
+#define START_NON_PRIVILEGED_PORT 1024
+
+/*
+ * Check and set errno helper
+ * Useful when send/recv gets us less than we wanted, and we want to set errno
+ * for the caller to know about the protocol Issue
+ */
+ #define CHECK_ERRNO(_ret)  {if (_ret >= 0 && errno == 0) { errno = EBADMSG; }}
+
+/*
+ * This function acquires and returns address family for vSockets.
+ * On failure returns -1 an sets errno (if not set by VMCISock_GetAFValue ())
+ *
+ * The address family for vSockets must be acquired, it is not static.
+ * The code opens and keeps FD to /dev/vsock to indicate to the kernel
+ * that VMCI driver is used by this process.
+ * Needs to be called once per process.
+ * <af> is expected to be closed by process completion
+ */
+static inline int
+vsock_get_family(void)
+{
+   static int af = -1;
+
+   errno = 0;
+   if (af == -1) { // TODO: for multi-thread will need a lock. Issue #35
+      af = VMCISock_GetAFValue();
+   }
+   if (af == -1 && errno == 0) {
+      errno = EAFNOSUPPORT; // report "family not supported" upstairs
+   }
+   return af;
+}
+
+#endif // _CONNECTION_TYPES_H_

drivers/storage/vmw/vmci/vmci.go

@@ -0,0 +1,174 @@
+// Copyright 2016 VMware, Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// The default (ESX) implementation of the VmdkCmdRunner interface.
+// This implementation sends synchronous commands to and receives responses
+// from ESX.
+
+// +build linux darwin
+// +build !libstorage_storage_driver libstorage_storage_driver_vmdk libstorage_storage_driver_photon
+
+package vmci
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"sync"
+	"syscall"
+	"time"
+	"unsafe"
+
+	log "github.com/Sirupsen/logrus"
+)
+
+/*
+#include "vmci_client.h"
+*/
+import "C"
+
+// EsxVmdkCmd struct - empty , we use it only to implement VmdkCmdRunner
+// interface
+type EsxVmdkCmd struct {
+	Mtx *sync.Mutex // For serialization of Run comand/response
+}
+
+const (
+	commBackendName string = "vsocket"
+	maxRetryCount          = 5
+	// Server side understand protocol version. If you are changing
+	// client/server protocol we use over VMCI, PLEASE DO NOT FORGET TO CHANGE
+	// IT FOR SERVER in file <vmdk_ops.py> !
+	clientProtocolVersion = "2"
+)
+
+// A request to be passed to ESX service
+type requestToVmci struct {
+	Ops     string     `json:"cmd"`
+	Details VolumeInfo `json:"details"`
+	Version string     `json:"version,omitempty"`
+}
+
+// VolumeInfo we get about the volume from upstairs
+type VolumeInfo struct {
+	Name    string            `json:"Name"`
+	Options map[string]string `json:"Opts,omitempty"`
+}
+
+type vmciError struct {
+	Error string `json:",omitempty"`
+}
+
+// EsxPort used to connect to ESX, passed in as command line param
+var EsxPort = 1019
+
+// Run command Guest VM requests on ESX via vmdkops_serv.py listening on
+// vSocket
+// *
+// * For each request:
+// *   - Establishes a vSocket connection
+// *   - Sends json string up to ESX
+// *   - waits for reply and returns resulting JSON or an error
+func (vmdkCmd EsxVmdkCmd) Run(
+	cmd string, name string, opts map[string]string) ([]byte, error) {
+
+	vmdkCmd.Mtx.Lock()
+	defer vmdkCmd.Mtx.Unlock()
+	protocolVersion := os.Getenv("VDVS_TEST_PROTOCOL_VERSION")
+	log.Debugf("Run get request: version=%s", protocolVersion)
+	if protocolVersion == "" {
+		protocolVersion = clientProtocolVersion
+	}
+	jsonStr, err := json.Marshal(&requestToVmci{
+		Ops:     cmd,
+		Details: VolumeInfo{Name: name, Options: opts},
+		Version: protocolVersion})
+	if err != nil {
+		return nil, fmt.Errorf("Failed to marshal json: %v", err)
+	}
+
+	cmdS := C.CString(string(jsonStr))
+	defer C.free(unsafe.Pointer(cmdS))
+
+	beS := C.CString(commBackendName)
+	defer C.free(unsafe.Pointer(beS))
+
+	// Get the response data in json
+	ans := (*C.be_answer)(C.calloc(1, C.sizeof_struct_be_answer))
+	defer C.free(unsafe.Pointer(ans))
+
+	var ret C.be_sock_status
+	for i := 0; i <= maxRetryCount; i++ {
+		ret, err = C.Vmci_GetReply(C.int(EsxPort), cmdS, beS, ans)
+		if ret == 0 {
+			// Received no error, exit loop.
+			// C.Vmci_GetReply indicates success/faulure by <ret> value.
+			// Cgo  interface adds <err> based on errno. We do not explicitly
+			// reset errno in our code. Still, we do not want a stale errno
+			// to confuse this code into thinking there was an error even when
+			// ret==0, so explicitly declare success on <ret> value only, and
+			break
+		}
+
+		var msg string
+		if err != nil {
+			var errno syscall.Errno
+			errno = err.(syscall.Errno)
+			msg = fmt.Sprintf("Run '%s' failed: %v (errno=%d) - %s",
+				cmd, err, int(errno), C.GoString(&ans.errBuf[0]))
+			if i < maxRetryCount {
+				log.Warnf(msg + " Retrying...")
+				time.Sleep(time.Second * 1)
+				continue
+			}
+			if errno == syscall.ECONNRESET || errno == syscall.ETIMEDOUT {
+				msg += " Cannot communicate with ESX, please refer to the " +
+					"FAQ " +
+					"https://github.com/vmware/docker-volume-vsphere/wiki#faq"
+			}
+		} else {
+			msg = fmt.Sprintf("Internal issue: ret != 0 but errno is not "+
+				"set. Cancelling operation - %s ", C.GoString(&ans.errBuf[0]))
+		}
+
+		log.Warnf(msg)
+		return nil, errors.New(msg)
+	}
+
+	response := []byte(C.GoString(ans.buf))
+	C.Vmci_FreeBuf(ans)
+
+	err = unmarshalError(response)
+	if err != nil && len(err.Error()) != 0 {
+		return nil, err
+	}
+	// There was no error, so return the slice containing the json response
+	return response, nil
+}
+
+func unmarshalError(str []byte) error {
+	// Unmarshalling null always succeeds
+	if string(str) == "null" {
+		return nil
+	}
+	errStruct := vmciError{}
+	err := json.Unmarshal(str, &errStruct)
+	if err != nil {
+		// We didn't unmarshal an error, so there is no error ;)
+		return nil
+	}
+	// Return the unmarshaled error string as an `error`
+	return errors.New(errStruct.Error)
+}