golang/xenlight/xenlight.go

/*
 * Copyright (C) 2016 George W. Dunlap, Citrix Systems UK Ltd
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; If not, see <http://www.gnu.org/licenses/>.
 */

// Package xenlight provides bindings to Xen's libxl C library.
package xenlight

/*

#cgo LDFLAGS: -lxenlight -lyajl -lxentoollog
#include <stdlib.h>
#include <libxl.h>
#include <libxl_utils.h>

#define INVALID_DOMID_TYPED ((uint32_t) INVALID_DOMID)

static const libxl_childproc_hooks childproc_hooks = { .chldowner = libxl_sigchld_owner_mainloop };

void xenlight_set_chldproc(libxl_ctx *ctx) {
	libxl_childproc_setmode(ctx, &childproc_hooks, NULL);
}
*/
import "C"

/*
 * Other flags that may be needed at some point:
 *  -lnl-route-3 -lnl-3
 *
 * To get back to static linking:
 * #cgo LDFLAGS: -lxenlight -lyajl_s -lxengnttab -lxenstore -lxenguest -lxentoollog -lxenevtchn -lxenctrl -lxenforeignmemory -lxencall -lz -luuid -lutil
 */

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"unsafe"
)

var libxlErrors = map[Error]string{
	ErrorNonspecific:                  "Non-specific error",
	ErrorVersion:                      "Wrong version",
	ErrorFail:                         "Failed",
	ErrorNi:                           "Not Implemented",
	ErrorNomem:                        "No memory",
	ErrorInval:                        "Invalid argument",
	ErrorBadfail:                      "Bad Fail",
	ErrorGuestTimedout:                "Guest timed out",
	ErrorTimedout:                     "Timed out",
	ErrorNoparavirt:                   "No Paravirtualization",
	ErrorNotReady:                     "Not ready",
	ErrorOseventRegFail:               "OS event registration failed",
	ErrorBufferfull:                   "Buffer full",
	ErrorUnknownChild:                 "Unknown child",
	ErrorLockFail:                     "Lock failed",
	ErrorJsonConfigEmpty:              "JSON config empty",
	ErrorDeviceExists:                 "Device exists",
	ErrorCheckpointDevopsDoesNotMatch: "Checkpoint devops does not match",
	ErrorCheckpointDeviceNotSupported: "Checkpoint device not supported",
	ErrorVnumaConfigInvalid:           "VNUMA config invalid",
	ErrorDomainNotfound:               "Domain not found",
	ErrorAborted:                      "Aborted",
	ErrorNotfound:                     "Not found",
	ErrorDomainDestroyed:              "Domain destroyed",
	ErrorFeatureRemoved:               "Feature removed",
}

const (
	DomidInvalid Domid = Domid(C.INVALID_DOMID_TYPED)
)

func (e Error) Error() string {
	if s, ok := libxlErrors[e]; ok {
		return s
	}

	return fmt.Sprintf("libxl error: %d", e)
}

// Context represents a libxl_ctx.
type Context struct {
	ctx         *C.libxl_ctx
	logger      *C.xentoollog_logger_stdiostream
	sigchld     chan os.Signal
	sigchldDone chan struct{}
}

// Golang always unmasks SIGCHLD, and internally has ways of
// distributing SIGCHLD to multiple recipients.  libxl has provision
// for this model: just tell it when a SIGCHLD happened, and it will
// look after its own processes.
//
// This should "play nicely" with other users of SIGCHLD as long as
// they don't reap libxl's processes.
//
// Every context needs to be notified on each SIGCHLD; so spin up a
// new goroutine for each context.  If there are a large number of
// contexts, this means each context will be woken up looking through
// its own list of children.
//
// The alternate would be to register a fork callback, such that the
// xenlight package can make a single list of all children, and only
// notify the specific libxl context(s) that have children woken.  But
// it's not clear to me this will be much more work than having the
// xenlight go library do the same thing; doing it in separate go
// threads has the potential to do it in parallel.  Leave that as an
// optimization for later if it turns out to be a bottleneck.
func sigchldHandler(ctx *Context) {
	for _ = range ctx.sigchld {
		C.libxl_childproc_sigchld_occurred(ctx.ctx)
	}
	close(ctx.sigchldDone)
}

// NewContext returns a new Context.
func NewContext() (ctx *Context, err error) {
	ctx = &Context{}

	defer func() {
		if err != nil {
			ctx.Close()
			ctx = nil
		}
	}()

	// Create a logger
	ctx.logger = C.xtl_createlogger_stdiostream(C.stderr, C.XTL_ERROR, 0)

	// Allocate a context
	ret := C.libxl_ctx_alloc(&ctx.ctx, C.LIBXL_VERSION, 0,
		(*C.xentoollog_logger)(unsafe.Pointer(ctx.logger)))
	if ret != 0 {
		return ctx, Error(ret)
	}

	// Tell libxl that we'll be dealing with SIGCHLD...
	C.xenlight_set_chldproc(ctx.ctx)

	// ...and arrange to keep that promise.
	ctx.sigchld = make(chan os.Signal, 2)
	ctx.sigchldDone = make(chan struct{}, 1)
	signal.Notify(ctx.sigchld, syscall.SIGCHLD)

	// This goroutine will run until the ctx.sigchld is closed in
	// ctx.Close(); at which point it will close ctx.sigchldDone.
	go sigchldHandler(ctx)

	return ctx, nil
}

// Close closes the Context.
func (ctx *Context) Close() error {
	// Tell our SIGCHLD notifier to shut down, and wait for it to exit
	// before we free the context.
	if ctx.sigchld != nil {
		signal.Stop(ctx.sigchld)
		close(ctx.sigchld)

		<-ctx.sigchldDone

		ctx.sigchld = nil
		ctx.sigchldDone = nil
	}

	if ctx.ctx != nil {
		ret := C.libxl_ctx_free(ctx.ctx)
		if ret != 0 {
			return Error(ret)
		}
		ctx.ctx = nil
	}

	if ctx.logger != nil {
		C.xtl_logger_destroy((*C.xentoollog_logger)(unsafe.Pointer(ctx.logger)))
		ctx.logger = nil
	}

	return nil
}

/*
 * Types: Builtins
 */

type Domid uint32

// NameToDomid returns the Domid for a domain, given its name, if it exists.
//
// NameToDomid does not guarantee that the domid associated with name at
// the time NameToDomid is called is the same as the domid associated with
// name at the time NameToDomid returns.
func (Ctx *Context) NameToDomid(name string) (Domid, error) {
	var domid C.uint32_t

	cname := C.CString(name)
	defer C.free(unsafe.Pointer(cname))

	if ret := C.libxl_name_to_domid(Ctx.ctx, cname, &domid); ret != 0 {
		return DomidInvalid, Error(ret)
	}

	return Domid(domid), nil
}

// DomidToName returns the name for a domain, given its domid. If there
// is no domain with the given domid, DomidToName will return the empty
// string.
//
// DomidToName does not guarantee that the name (if any) associated with domid
// at the time DomidToName is called is the same as the name (if any) associated
// with domid at the time DomidToName returns.
func (Ctx *Context) DomidToName(domid Domid) string {
	cname := C.libxl_domid_to_name(Ctx.ctx, C.uint32_t(domid))
	defer C.free(unsafe.Pointer(cname))

	return C.GoString(cname)
}

// Devid is a device ID.
type Devid int

// Uuid is a domain UUID.
type Uuid [16]byte

// String formats a Uuid in the form "xxxx-xx-xx-xx-xxxxxx".
func (u Uuid) String() string {
	s := "%x%x%x%x-%x%x-%x%x-%x%x-%x%x%x%x%x%x"
	opts := make([]interface{}, 16)

	for i, v := range u {
		opts[i] = v
	}

	return fmt.Sprintf(s, opts...)
}

func (u *Uuid) fromC(c *C.libxl_uuid) error {
	for i := range *u {
		u[i] = byte(c.uuid[i])
	}

	return nil
}

func (u *Uuid) toC(cu *C.libxl_uuid) error {
	for i, v := range u {
		cu.uuid[i] = C.uint8_t(v)
	}

	return nil
}

// defboolVal represents a defbool value.
type defboolVal int

const (
	defboolDefault defboolVal = 0
	defboolFalse   defboolVal = -1
	defboolTrue    defboolVal = 1
)

// Defbool represents a libxl_defbool.
type Defbool struct {
	val defboolVal
}

func (d Defbool) String() string {
	switch d.val {
	case defboolDefault:
		return "<default>"
	case defboolFalse:
		return "False"
	case defboolTrue:
		return "True"
	}

	return ""
}

// Set sets the value of the Defbool.
func (d *Defbool) Set(b bool) {
	if b {
		d.val = defboolTrue
		return
	}
	d.val = defboolFalse
}

// Unset resets the Defbool to default value.
func (d *Defbool) Unset() {
	d.val = defboolDefault
}

// SetIfDefault sets the value of Defbool only if
// its current value is default.
func (d *Defbool) SetIfDefault(b bool) {
	if d.IsDefault() {
		d.Set(b)
	}
}

// IsDefault returns true if the value of Defbool
// is default, returns false otherwise.
func (d *Defbool) IsDefault() bool {
	return d.val == defboolDefault
}

// Val returns the boolean value associated with the
// Defbool value. An error is returned if the value
// is default.
func (d *Defbool) Val() (bool, error) {
	if d.IsDefault() {
		return false, fmt.Errorf("%v: cannot take value of default defbool", ErrorInval)
	}

	return (d.val > 0), nil
}

func (d *Defbool) fromC(c *C.libxl_defbool) error {
	if C.libxl_defbool_is_default(*c) {
		d.val = defboolDefault
		return nil
	}

	if C.libxl_defbool_val(*c) {
		d.val = defboolTrue
		return nil
	}

	d.val = defboolFalse

	return nil
}

func (d *Defbool) toC(cd *C.libxl_defbool) error {
	if !d.IsDefault() {
		val, _ := d.Val()
		C.libxl_defbool_set(cd, C.bool(val))
	}

	return nil
}

// Mac represents a libxl_mac, or simply a MAC address.
type Mac [6]byte

// String formats a Mac address to string representation.
func (mac Mac) String() string {
	s := "%02x:%02x:%02x:%02x:%02x:%02x"
	opts := make([]interface{}, 6)

	for i, v := range mac {
		opts[i] = v
	}

	return fmt.Sprintf(s, opts...)
}

func (mac *Mac) fromC(cmac *C.libxl_mac) error {
	for i := range *mac {
		mac[i] = byte(cmac[i])
	}

	return nil
}

func (mac Mac) toC(cm *C.libxl_mac) error {
	for i, v := range mac {
		(*cm)[i] = C.uint8_t(v)
	}

	return nil
}

// MsVmGenid represents a libxl_ms_vm_genid.
type MsVmGenid [int(C.LIBXL_MS_VM_GENID_LEN)]byte

func (mvg *MsVmGenid) fromC(cmvg *C.libxl_ms_vm_genid) error {
	for i := range *mvg {
		mvg[i] = byte(cmvg.bytes[i])
	}

	return nil
}

func (mvg *MsVmGenid) toC(cmvg *C.libxl_ms_vm_genid) error {
	for i, v := range mvg {
		cmvg.bytes[i] = C.uint8_t(v)
	}

	return nil
}

// EvLink represents a libxl_ev_link.
//
// Represented as an empty struct for now, as there is no
// apparent need for the internals of this type to be exposed
// through the Go package.
type EvLink struct{}

func (el *EvLink) fromC(cel *C.libxl_ev_link) error     { return nil }
func (el *EvLink) toC(cel *C.libxl_ev_link) (err error) { return }

// CpuidPolicyList represents a libxl_cpuid_policy_list.
//
// The value of CpuidPolicyList is honored when used as input to libxl. If
// a struct contains a field of type CpuidPolicyList, that field will be left
// empty when it is returned from libxl.
type CpuidPolicyList string

func (cpl *CpuidPolicyList) fromC(ccpl *C.libxl_cpuid_policy_list) error { *cpl = ""; return nil }

func (cpl CpuidPolicyList) toC(ccpl *C.libxl_cpuid_policy_list) error {
	if cpl == "" {
		*ccpl = nil
		return nil
	}

	s := C.CString(string(cpl))
	defer C.free(unsafe.Pointer(s))

	ret := C.libxl_cpuid_parse_config(ccpl, s)
	if ret != 0 {
		C.libxl_cpuid_dispose(ccpl)

		// libxl_cpuid_parse_config doesn't return a normal libxl error.
		return ErrorInval
	}

	return nil
}

// Hwcap represents a libxl_hwcap.
type Hwcap [8]uint32

func (hwcap *Hwcap) fromC(chwcap *C.libxl_hwcap) error {
	for i := range *hwcap {
		hwcap[i] = uint32(chwcap[i])
	}

	return nil
}

func (hwcap *Hwcap) toC(chwcap *C.libxl_hwcap) error {
	for i, v := range hwcap {
		(*chwcap)[i] = C.uint32_t(v)
	}

	return nil
}

// KeyValueList represents a libxl_key_value_list.
//
// Represented as an empty struct for now, as there is no
// apparent need for this type to be exposed through the
// Go package.
type KeyValueList struct{}

func (kvl KeyValueList) fromC(ckvl *C.libxl_key_value_list) error     { return nil }
func (kvl KeyValueList) toC(ckvl *C.libxl_key_value_list) (err error) { return }

// StringList represents a libxl_string_list.
type StringList []string

func (sl *StringList) fromC(csl *C.libxl_string_list) error {
	size := int(C.libxl_string_list_length(csl))
	list := (*[1 << 30]*C.char)(unsafe.Pointer(csl))[:size:size]

	*sl = make([]string, size)

	for i, v := range list {
		(*sl)[i] = C.GoString(v)
	}

	return nil
}

func (sl StringList) toC(csl *C.libxl_string_list) error {
	var char *C.char
	size := len(sl)
	*csl = (C.libxl_string_list)(C.malloc(C.ulong(size) * C.ulong(unsafe.Sizeof(char))))
	clist := (*[1 << 30]*C.char)(unsafe.Pointer(csl))[:size:size]

	for i, v := range sl {
		clist[i] = C.CString(v)
	}

	return nil
}

// Bitmap represents a libxl_bitmap.
//
// Implement the Go bitmap type such that the underlying data can
// easily be copied in and out.  NB that we still have to do copies
// both directions, because cgo runtime restrictions forbid passing to
// a C function a pointer to a Go-allocated structure which contains a
// pointer.
type Bitmap struct {
	// typedef struct {
	//     uint32_t size;          /* number of bytes in map */
	//     uint8_t *map;
	// } libxl_bitmap;
	bitmap []C.uint8_t
}

func (bm *Bitmap) fromC(cbm *C.libxl_bitmap) error {
	bm.bitmap = nil
	if size := int(cbm.size); size > 0 {
		// Alloc a Go slice for the bytes
		bm.bitmap = make([]C.uint8_t, size)

		// Make a slice pointing to the C array
		cs := (*[1 << 30]C.uint8_t)(unsafe.Pointer(cbm._map))[:size:size]

		// And copy the C array into the Go array
		copy(bm.bitmap, cs)
	}

	return nil
}

func (bm *Bitmap) toC(cbm *C.libxl_bitmap) error {
	size := len(bm.bitmap)
	cbm.size = C.uint32_t(size)
	if cbm.size > 0 {
		cbm._map = (*C.uint8_t)(C.malloc(C.ulong(cbm.size) * C.sizeof_uint8_t))
		cs := (*[1 << 31]C.uint8_t)(unsafe.Pointer(cbm._map))[:size:size]

		copy(cs, bm.bitmap)
	}

	return nil
}

func (sr ShutdownReason) String() (str string) {
	cstr := C.libxl_shutdown_reason_to_string(C.libxl_shutdown_reason(sr))
	str = C.GoString(cstr)

	return
}

func (dt DomainType) String() (str string) {
	cstr := C.libxl_domain_type_to_string(C.libxl_domain_type(dt))
	str = C.GoString(cstr)

	return
}

// const char *libxl_scheduler_to_string(libxl_scheduler p);
func (s Scheduler) String() string {
	cs := C.libxl_scheduler_to_string(C.libxl_scheduler(s))
	// No need to free const return value

	return C.GoString(cs)
}

// int libxl_scheduler_from_string(const char *s, libxl_scheduler *e);
func (s *Scheduler) FromString(gstr string) (err error) {
	*s, err = SchedulerFromString(gstr)
	return
}

func SchedulerFromString(name string) (s Scheduler, err error) {
	cname := C.CString(name)
	defer C.free(unsafe.Pointer(cname))

	var cs C.libxl_scheduler

	ret := C.libxl_scheduler_from_string(cname, &cs)
	if ret != 0 {
		err = Error(-ret)
		return
	}

	s = Scheduler(cs)

	return
}

// libxl_cpupoolinfo * libxl_list_cpupool(libxl_ctx*, int *nb_pool_out);
// void libxl_cpupoolinfo_list_free(libxl_cpupoolinfo *list, int nb_pool);
func (Ctx *Context) ListCpupool() (list []Cpupoolinfo) {
	var nbPool C.int

	c_cpupool_list := C.libxl_list_cpupool(Ctx.ctx, &nbPool)

	defer C.libxl_cpupoolinfo_list_free(c_cpupool_list, nbPool)

	if int(nbPool) == 0 {
		return
	}

	// Magic
	cpupoolListSlice := (*[1 << 30]C.libxl_cpupoolinfo)(unsafe.Pointer(c_cpupool_list))[:nbPool:nbPool]
	for i := range cpupoolListSlice {
		var info Cpupoolinfo
		_ = info.fromC(&cpupoolListSlice[i])
		list = append(list, info)
	}

	return
}

// int libxl_cpupool_info(libxl_ctx *ctx, libxl_cpupoolinfo *info, uint32_t poolid);
func (Ctx *Context) CpupoolInfo(Poolid uint32) (pool Cpupoolinfo, err error) {
	var c_cpupool C.libxl_cpupoolinfo

	ret := C.libxl_cpupool_info(Ctx.ctx, &c_cpupool, C.uint32_t(Poolid))
	if ret != 0 {
		err = Error(-ret)
		return
	}
	defer C.libxl_cpupoolinfo_dispose(&c_cpupool)

	err = pool.fromC(&c_cpupool)

	return
}

// int libxl_cpupool_create(libxl_ctx *ctx, const char *name,
//                          libxl_scheduler sched,
//                          libxl_bitmap cpumap, libxl_uuid *uuid,
//                          uint32_t *poolid);
// FIXME: uuid
// FIXME: Setting poolid
func (Ctx *Context) CpupoolCreate(Name string, Scheduler Scheduler, Cpumap Bitmap) (err error, Poolid uint32) {
	poolid := C.uint32_t(C.LIBXL_CPUPOOL_POOLID_ANY)
	name := C.CString(Name)
	defer C.free(unsafe.Pointer(name))

	// For now, just do what xl does, and make a new uuid every time we create the pool
	var uuid C.libxl_uuid
	C.libxl_uuid_generate(&uuid)

	var cbm C.libxl_bitmap
	if err = Cpumap.toC(&cbm); err != nil {
		return
	}
	defer C.libxl_bitmap_dispose(&cbm)

	ret := C.libxl_cpupool_create(Ctx.ctx, name, C.libxl_scheduler(Scheduler),
		cbm, &uuid, &poolid)
	if ret != 0 {
		err = Error(-ret)
		return
	}

	Poolid = uint32(poolid)

	return
}

// int libxl_cpupool_destroy(libxl_ctx *ctx, uint32_t poolid);
func (Ctx *Context) CpupoolDestroy(Poolid uint32) (err error) {
	ret := C.libxl_cpupool_destroy(Ctx.ctx, C.uint32_t(Poolid))
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

// int libxl_cpupool_cpuadd(libxl_ctx *ctx, uint32_t poolid, int cpu);
func (Ctx *Context) CpupoolCpuadd(Poolid uint32, Cpu int) (err error) {
	ret := C.libxl_cpupool_cpuadd(Ctx.ctx, C.uint32_t(Poolid), C.int(Cpu))
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

// int libxl_cpupool_cpuadd_cpumap(libxl_ctx *ctx, uint32_t poolid,
//                                 const libxl_bitmap *cpumap);
func (Ctx *Context) CpupoolCpuaddCpumap(Poolid uint32, Cpumap Bitmap) (err error) {
	var cbm C.libxl_bitmap
	if err = Cpumap.toC(&cbm); err != nil {
		return
	}
	defer C.libxl_bitmap_dispose(&cbm)

	ret := C.libxl_cpupool_cpuadd_cpumap(Ctx.ctx, C.uint32_t(Poolid), &cbm)
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

// int libxl_cpupool_cpuremove(libxl_ctx *ctx, uint32_t poolid, int cpu);
func (Ctx *Context) CpupoolCpuremove(Poolid uint32, Cpu int) (err error) {
	ret := C.libxl_cpupool_cpuremove(Ctx.ctx, C.uint32_t(Poolid), C.int(Cpu))
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

// int libxl_cpupool_cpuremove_cpumap(libxl_ctx *ctx, uint32_t poolid,
//                                    const libxl_bitmap *cpumap);
func (Ctx *Context) CpupoolCpuremoveCpumap(Poolid uint32, Cpumap Bitmap) (err error) {
	var cbm C.libxl_bitmap
	if err = Cpumap.toC(&cbm); err != nil {
		return
	}
	defer C.libxl_bitmap_dispose(&cbm)

	ret := C.libxl_cpupool_cpuremove_cpumap(Ctx.ctx, C.uint32_t(Poolid), &cbm)
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

// int libxl_cpupool_rename(libxl_ctx *ctx, const char *name, uint32_t poolid);
func (Ctx *Context) CpupoolRename(Name string, Poolid uint32) (err error) {
	name := C.CString(Name)
	defer C.free(unsafe.Pointer(name))

	ret := C.libxl_cpupool_rename(Ctx.ctx, name, C.uint32_t(Poolid))
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

// int libxl_cpupool_cpuadd_node(libxl_ctx *ctx, uint32_t poolid, int node, int *cpus);
func (Ctx *Context) CpupoolCpuaddNode(Poolid uint32, Node int) (Cpus int, err error) {
	ccpus := C.int(0)

	ret := C.libxl_cpupool_cpuadd_node(Ctx.ctx, C.uint32_t(Poolid), C.int(Node), &ccpus)
	if ret != 0 {
		err = Error(-ret)
		return
	}

	Cpus = int(ccpus)

	return
}

// int libxl_cpupool_cpuremove_node(libxl_ctx *ctx, uint32_t poolid, int node, int *cpus);
func (Ctx *Context) CpupoolCpuremoveNode(Poolid uint32, Node int) (Cpus int, err error) {
	ccpus := C.int(0)

	ret := C.libxl_cpupool_cpuremove_node(Ctx.ctx, C.uint32_t(Poolid), C.int(Node), &ccpus)
	if ret != 0 {
		err = Error(-ret)
		return
	}

	Cpus = int(ccpus)

	return
}

// int libxl_cpupool_movedomain(libxl_ctx *ctx, uint32_t poolid, uint32_t domid);
func (Ctx *Context) CpupoolMovedomain(Poolid uint32, Id Domid) (err error) {
	ret := C.libxl_cpupool_movedomain(Ctx.ctx, C.uint32_t(Poolid), C.uint32_t(Id))
	if ret != 0 {
		err = Error(-ret)
		return
	}

	return
}

//
// Utility functions
//
func (Ctx *Context) CpupoolFindByName(name string) (info Cpupoolinfo, found bool) {
	plist := Ctx.ListCpupool()

	for i := range plist {
		if plist[i].PoolName == name {
			found = true
			info = plist[i]
			return
		}
	}
	return
}

func (Ctx *Context) CpupoolMakeFree(Cpumap Bitmap) (err error) {
	plist := Ctx.ListCpupool()

	for i := range plist {
		var Intersection Bitmap
		Intersection = Cpumap.And(plist[i].Cpumap)
		if !Intersection.IsEmpty() {
			err = Ctx.CpupoolCpuremoveCpumap(plist[i].Poolid, Intersection)
			if err != nil {
				return
			}
		}
	}
	return
}

/*
 * Bitmap operations
 */

func (bm *Bitmap) Test(bit int) bool {
	ubit := uint(bit)
	if bit > bm.Max() || bm.bitmap == nil {
		return false
	}

	return (bm.bitmap[bit/8] & (1 << (ubit & 7))) != 0
}

func (bm *Bitmap) Set(bit int) {
	ibit := bit / 8
	if ibit+1 > len(bm.bitmap) {
		bm.bitmap = append(bm.bitmap, make([]C.uint8_t, ibit+1-len(bm.bitmap))...)
	}

	bm.bitmap[ibit] |= 1 << (uint(bit) & 7)
}

func (bm *Bitmap) SetRange(start int, end int) {
	for i := start; i <= end; i++ {
		bm.Set(i)
	}
}

func (bm *Bitmap) Clear(bit int) {
	ubit := uint(bit)
	if bit > bm.Max() || bm.bitmap == nil {
		return
	}

	bm.bitmap[bit/8] &= ^(1 << (ubit & 7))
}

func (bm *Bitmap) ClearRange(start int, end int) {
	for i := start; i <= end; i++ {
		bm.Clear(i)
	}
}

func (bm *Bitmap) Max() int {
	return len(bm.bitmap)*8 - 1
}

func (bm *Bitmap) IsEmpty() bool {
	for i := 0; i < len(bm.bitmap); i++ {
		if bm.bitmap[i] != 0 {
			return false
		}
	}
	return true
}

func (a Bitmap) And(b Bitmap) (c Bitmap) {
	var max, min int
	if len(a.bitmap) > len(b.bitmap) {
		max = len(a.bitmap)
		min = len(b.bitmap)
	} else {
		max = len(b.bitmap)
		min = len(a.bitmap)
	}
	c.bitmap = make([]C.uint8_t, max)

	for i := 0; i < min; i++ {
		c.bitmap[i] = a.bitmap[i] & b.bitmap[i]
	}
	return
}

func (bm Bitmap) String() (s string) {
	lastOnline := false
	crange := false
	printed := false
	var i int
	/// --x-xxxxx-x -> 2,4-8,10
	/// --x-xxxxxxx -> 2,4-10
	for i = 0; i <= bm.Max(); i++ {
		if bm.Test(i) {
			if !lastOnline {
				// Switching offline -> online, print this cpu
				if printed {
					s += ","
				}
				s += fmt.Sprintf("%d", i)
				printed = true
			} else if !crange {
				// last was online, but we're not in a range; print -
				crange = true
				s += "-"
			} else {
				// last was online, we're in a range,  nothing else to do
			}
			lastOnline = true
		} else {
			if lastOnline {
				// Switching online->offline; do we need to end a range?
				if crange {
					s += fmt.Sprintf("%d", i-1)
				}
			}
			lastOnline = false
			crange = false
		}
	}
	if lastOnline {
		// Switching online->offline; do we need to end a range?
		if crange {
			s += fmt.Sprintf("%d", i-1)
		}
	}

	return
}

//int libxl_get_max_cpus(libxl_ctx *ctx);
func (Ctx *Context) GetMaxCpus() (maxCpus int, err error) {
	ret := C.libxl_get_max_cpus(Ctx.ctx)
	if ret < 0 {
		err = Error(-ret)
		return
	}
	maxCpus = int(ret)
	return
}

//int libxl_get_online_cpus(libxl_ctx *ctx);
func (Ctx *Context) GetOnlineCpus() (onCpus int, err error) {
	ret := C.libxl_get_online_cpus(Ctx.ctx)
	if ret < 0 {
		err = Error(-ret)
		return
	}
	onCpus = int(ret)
	return
}

//int libxl_get_max_nodes(libxl_ctx *ctx);
func (Ctx *Context) GetMaxNodes() (maxNodes int, err error) {
	ret := C.libxl_get_max_nodes(Ctx.ctx)
	if ret < 0 {
		err = Error(-ret)
		return
	}
	maxNodes = int(ret)
	return
}

//int libxl_get_free_memory(libxl_ctx *ctx, uint64_t *memkb);
func (Ctx *Context) GetFreeMemory() (memkb uint64, err error) {
	var cmem C.uint64_t
	ret := C.libxl_get_free_memory(Ctx.ctx, &cmem)

	if ret < 0 {
		err = Error(-ret)
		return
	}

	memkb = uint64(cmem)
	return

}

//int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
func (Ctx *Context) GetPhysinfo() (physinfo *Physinfo, err error) {
	var cphys C.libxl_physinfo
	C.libxl_physinfo_init(&cphys)
	defer C.libxl_physinfo_dispose(&cphys)

	ret := C.libxl_get_physinfo(Ctx.ctx, &cphys)

	if ret < 0 {
		err = Error(ret)
		return
	}
	err = physinfo.fromC(&cphys)

	return
}

//const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx);
func (Ctx *Context) GetVersionInfo() (info *VersionInfo, err error) {
	var cinfo *C.libxl_version_info

	cinfo = C.libxl_get_version_info(Ctx.ctx)

	err = info.fromC(cinfo)

	return
}

func (Ctx *Context) DomainInfo(Id Domid) (di *Dominfo, err error) {
	var cdi C.libxl_dominfo
	C.libxl_dominfo_init(&cdi)
	defer C.libxl_dominfo_dispose(&cdi)

	ret := C.libxl_domain_info(Ctx.ctx, &cdi, C.uint32_t(Id))

	if ret != 0 {
		err = Error(-ret)
		return
	}

	err = di.fromC(&cdi)

	return
}

func (Ctx *Context) DomainUnpause(Id Domid) (err error) {
	ret := C.libxl_domain_unpause(Ctx.ctx, C.uint32_t(Id), nil)

	if ret != 0 {
		err = Error(-ret)
	}
	return
}

//int libxl_domain_pause(libxl_ctx *ctx, uint32_t domain);
func (Ctx *Context) DomainPause(id Domid) (err error) {
	ret := C.libxl_domain_pause(Ctx.ctx, C.uint32_t(id), nil)

	if ret != 0 {
		err = Error(-ret)
	}
	return
}

//int libxl_domain_shutdown(libxl_ctx *ctx, uint32_t domid);
func (Ctx *Context) DomainShutdown(id Domid) (err error) {
	ret := C.libxl_domain_shutdown(Ctx.ctx, C.uint32_t(id), nil)

	if ret != 0 {
		err = Error(-ret)
	}
	return
}

//int libxl_domain_reboot(libxl_ctx *ctx, uint32_t domid);
func (Ctx *Context) DomainReboot(id Domid) (err error) {
	ret := C.libxl_domain_reboot(Ctx.ctx, C.uint32_t(id), nil)

	if ret != 0 {
		err = Error(-ret)
	}
	return
}

//libxl_dominfo * libxl_list_domain(libxl_ctx*, int *nb_domain_out);
//void libxl_dominfo_list_free(libxl_dominfo *list, int nb_domain);
func (Ctx *Context) ListDomain() (glist []Dominfo) {
	var nbDomain C.int
	clist := C.libxl_list_domain(Ctx.ctx, &nbDomain)
	defer C.libxl_dominfo_list_free(clist, nbDomain)

	if int(nbDomain) == 0 {
		return
	}

	gslice := (*[1 << 30]C.libxl_dominfo)(unsafe.Pointer(clist))[:nbDomain:nbDomain]
	for i := range gslice {
		var info Dominfo
		_ = info.fromC(&gslice[i])
		glist = append(glist, info)
	}

	return
}

//libxl_vcpuinfo *libxl_list_vcpu(libxl_ctx *ctx, uint32_t domid,
//				int *nb_vcpu, int *nr_cpus_out);
//void libxl_vcpuinfo_list_free(libxl_vcpuinfo *, int nr_vcpus);
func (Ctx *Context) ListVcpu(id Domid) (glist []Vcpuinfo) {
	var nbVcpu C.int
	var nrCpu C.int

	clist := C.libxl_list_vcpu(Ctx.ctx, C.uint32_t(id), &nbVcpu, &nrCpu)
	defer C.libxl_vcpuinfo_list_free(clist, nbVcpu)

	if int(nbVcpu) == 0 {
		return
	}

	gslice := (*[1 << 30]C.libxl_vcpuinfo)(unsafe.Pointer(clist))[:nbVcpu:nbVcpu]
	for i := range gslice {
		var info Vcpuinfo
		_ = info.fromC(&gslice[i])
		glist = append(glist, info)
	}

	return
}

func (ct ConsoleType) String() (str string) {
	cstr := C.libxl_console_type_to_string(C.libxl_console_type(ct))
	str = C.GoString(cstr)

	return
}

//int libxl_console_get_tty(libxl_ctx *ctx, uint32_t domid, int cons_num,
//libxl_console_type type, char **path);
func (Ctx *Context) ConsoleGetTty(id Domid, consNum int, conType ConsoleType) (path string, err error) {
	var cpath *C.char
	ret := C.libxl_console_get_tty(Ctx.ctx, C.uint32_t(id), C.int(consNum), C.libxl_console_type(conType), &cpath)
	if ret != 0 {
		err = Error(-ret)
		return
	}
	defer C.free(unsafe.Pointer(cpath))

	path = C.GoString(cpath)
	return
}

//int libxl_primary_console_get_tty(libxl_ctx *ctx, uint32_t domid_vm,
//					char **path);
func (Ctx *Context) PrimaryConsoleGetTty(domid uint32) (path string, err error) {
	var cpath *C.char
	ret := C.libxl_primary_console_get_tty(Ctx.ctx, C.uint32_t(domid), &cpath)
	if ret != 0 {
		err = Error(-ret)
		return
	}
	defer C.free(unsafe.Pointer(cpath))

	path = C.GoString(cpath)
	return
}

// DeviceNicAdd adds a nic to a domain.
func (Ctx *Context) DeviceNicAdd(domid Domid, nic *DeviceNic) error {
	var cnic C.libxl_device_nic

	if err := nic.toC(&cnic); err != nil {
		return err
	}
	defer C.libxl_device_nic_dispose(&cnic)

	ret := C.libxl_device_nic_add(Ctx.ctx, C.uint32_t(domid), &cnic, nil)
	if ret != 0 {
		return Error(ret)
	}

	return nil
}

// DeviceNicRemove removes a nic from a domain.
func (Ctx *Context) DeviceNicRemove(domid Domid, nic *DeviceNic) error {
	var cnic C.libxl_device_nic

	if err := nic.toC(&cnic); err != nil {
		return err
	}
	defer C.libxl_device_nic_dispose(&cnic)

	ret := C.libxl_device_nic_remove(Ctx.ctx, C.uint32_t(domid), &cnic, nil)
	if ret != 0 {
		return Error(ret)
	}

	return nil
}

// DevicePciAdd is used to passthrough a PCI device to a domain.
func (Ctx *Context) DevicePciAdd(domid Domid, pci *DevicePci) error {
	var cpci C.libxl_device_pci

	if err := pci.toC(&cpci); err != nil {
		return err
	}
	defer C.libxl_device_pci_dispose(&cpci)

	ret := C.libxl_device_pci_add(Ctx.ctx, C.uint32_t(domid), &cpci, nil)
	if ret != 0 {
		return Error(ret)
	}

	return nil
}

// DevicePciRemove removes a PCI device from a domain.
func (Ctx *Context) DevicePciRemove(domid Domid, pci *DevicePci) error {
	var cpci C.libxl_device_pci

	if err := pci.toC(&cpci); err != nil {
		return err
	}
	defer C.libxl_device_pci_dispose(&cpci)

	ret := C.libxl_device_pci_remove(Ctx.ctx, C.uint32_t(domid), &cpci, nil)
	if ret != 0 {
		return Error(ret)
	}

	return nil
}

// DeviceUsbdevAdd adds a USB device to a domain.
func (Ctx *Context) DeviceUsbdevAdd(domid Domid, usbdev *DeviceUsbdev) error {
	var cusbdev C.libxl_device_usbdev

	if err := usbdev.toC(&cusbdev); err != nil {
		return err
	}
	defer C.libxl_device_usbdev_dispose(&cusbdev)

	ret := C.libxl_device_usbdev_add(Ctx.ctx, C.uint32_t(domid), &cusbdev, nil)
	if ret != 0 {
		return Error(ret)
	}

	return nil
}

// DeviceUsbdevRemove removes a USB device from a domain.
func (Ctx *Context) DeviceUsbdevRemove(domid Domid, usbdev *DeviceUsbdev) error {
	var cusbdev C.libxl_device_usbdev

	if err := usbdev.toC(&cusbdev); err != nil {
		return err
	}
	defer C.libxl_device_usbdev_dispose(&cusbdev)

	ret := C.libxl_device_usbdev_remove(Ctx.ctx, C.uint32_t(domid), &cusbdev, nil)
	if ret != 0 {
		return Error(ret)
	}

	return nil
}

// DomainCreateNew creates a new domain.
func (Ctx *Context) DomainCreateNew(config *DomainConfig) (Domid, error) {
	var cdomid C.uint32_t
	var cconfig C.libxl_domain_config
	err := config.toC(&cconfig)
	if err != nil {
		return Domid(0), fmt.Errorf("converting domain config to C: %v", err)
	}
	defer C.libxl_domain_config_dispose(&cconfig)

	ret := C.libxl_domain_create_new(Ctx.ctx, &cconfig, &cdomid, nil, nil)
	if ret != 0 {
		return Domid(0), Error(ret)
	}

	return Domid(cdomid), nil
}