windows: add various functions for shutting down and logging out

There are a few functions to control the behavior of shutdown and
logout, both for what the current process does during shutdown, and also
whether or not the current process is running in an interactive session.
The below code is a port of the MSDN example code to Go using one of the
added new functions:

https://docs.microsoft.com/en-us/windows/win32/shutdown/how-to-shut-down-the-system

func shutdownLikeMSDNDoes() error {
  seShutdownName, err := windows.UTF16PtrFromString("SeShutdownPrivilege")
  if err != nil {
    return err
  }

  var shutdownPriv windows.Tokenprivileges
  err = windows.LookupPrivilegeValue(nil, seShutdownName, &shutdownPriv.Privileges[0].Luid)
  if err != nil {
    return err
  }
  shutdownPriv.Privileges[0].Attributes = windows.SE_PRIVILEGE_ENABLED
  shutdownPriv.PrivilegeCount = 1

  process, err := windows.GetCurrentProcess()
  if err != nil {
    return err
  }
  var token windows.Token
  err = windows.OpenProcessToken(process, windows.TOKEN_ADJUST_PRIVILEGES | windows.TOKEN_QUERY, &token)
  if err != nil {
    return err
  }
  defer token.Close()

  err = windows.AdjustTokenPrivileges(token, false, &shutdownPriv, 0, nil, nil)
  if err != nil {
    return err
  }

  err = windows.ExitWindowsEx(windows.EWX_SHUTDOWN | windows.EWX_FORCE,
    windows.SHTDN_REASON_MAJOR_OPERATINGSYSTEM | windows.SHTDN_REASON_MINOR_UPGRADE | windows.SHTDN_REASON_FLAG_PLANNED)
  if err != nil {
    return err
  }

  return nil
}

Note, though, that this function doesn't set the token privs back to how
they were before, which isn't good. A more robust method than the MSDN
one above would be to duplicate&impersonate.

Fixes: golang/go#34271
Change-Id: Ibe55ddd35b709d9ab793cb9af47c39901c5e5c69
Reviewed-on: https://go-review.googlesource.com/c/sys/+/195497
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bruce Downs <bruceadowns@gmail.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

windows/syscall_windows.go

@@ -296,6 +296,10 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetVolumeLabel(rootPathName *uint16, volumeName *uint16) (err error) = SetVolumeLabelW
 //sys	SetVolumeMountPoint(volumeMountPoint *uint16, volumeName *uint16) (err error) = SetVolumeMountPointW
 //sys	MessageBox(hwnd Handle, text *uint16, caption *uint16, boxtype uint32) (ret int32, err error) [failretval==0] = user32.MessageBoxW
+//sys	ExitWindowsEx(flags uint32, reason uint32) (err error) = user32.ExitWindowsEx
+//sys	InitiateSystemShutdownEx(machineName *uint16, message *uint16, timeout uint32, forceAppsClosed bool, rebootAfterShutdown bool, reason uint32) (err error) = advapi32.InitiateSystemShutdownExW
+//sys	SetProcessShutdownParameters(level uint32, flags uint32) (err error) = kernel32.SetProcessShutdownParameters
+//sys	GetProcessShutdownParameters(level *uint32, flags *uint32) (err error) = kernel32.GetProcessShutdownParameters
 //sys	clsidFromString(lpsz *uint16, pclsid *GUID) (ret error) = ole32.CLSIDFromString
 //sys	stringFromGUID2(rguid *GUID, lpsz *uint16, cchMax int32) (chars int32) = ole32.StringFromGUID2
 //sys	coCreateGuid(pguid *GUID) (ret error) = ole32.CoCreateGuid

windows/types_windows.go

@@ -1688,3 +1688,68 @@ type OsVersionInfoEx struct {
 	ProductType       byte
 	_                 byte
 }
+
+const (
+	EWX_LOGOFF          = 0x00000000
+	EWX_SHUTDOWN        = 0x00000001
+	EWX_REBOOT          = 0x00000002
+	EWX_FORCE           = 0x00000004
+	EWX_POWEROFF        = 0x00000008
+	EWX_FORCEIFHUNG     = 0x00000010
+	EWX_QUICKRESOLVE    = 0x00000020
+	EWX_RESTARTAPPS     = 0x00000040
+	EWX_HYBRID_SHUTDOWN = 0x00400000
+	EWX_BOOTOPTIONS     = 0x01000000
+
+	SHTDN_REASON_FLAG_COMMENT_REQUIRED          = 0x01000000
+	SHTDN_REASON_FLAG_DIRTY_PROBLEM_ID_REQUIRED = 0x02000000
+	SHTDN_REASON_FLAG_CLEAN_UI                  = 0x04000000
+	SHTDN_REASON_FLAG_DIRTY_UI                  = 0x08000000
+	SHTDN_REASON_FLAG_USER_DEFINED              = 0x40000000
+	SHTDN_REASON_FLAG_PLANNED                   = 0x80000000
+	SHTDN_REASON_MAJOR_OTHER                    = 0x00000000
+	SHTDN_REASON_MAJOR_NONE                     = 0x00000000
+	SHTDN_REASON_MAJOR_HARDWARE                 = 0x00010000
+	SHTDN_REASON_MAJOR_OPERATINGSYSTEM          = 0x00020000
+	SHTDN_REASON_MAJOR_SOFTWARE                 = 0x00030000
+	SHTDN_REASON_MAJOR_APPLICATION              = 0x00040000
+	SHTDN_REASON_MAJOR_SYSTEM                   = 0x00050000
+	SHTDN_REASON_MAJOR_POWER                    = 0x00060000
+	SHTDN_REASON_MAJOR_LEGACY_API               = 0x00070000
+	SHTDN_REASON_MINOR_OTHER                    = 0x00000000
+	SHTDN_REASON_MINOR_NONE                     = 0x000000ff
+	SHTDN_REASON_MINOR_MAINTENANCE              = 0x00000001
+	SHTDN_REASON_MINOR_INSTALLATION             = 0x00000002
+	SHTDN_REASON_MINOR_UPGRADE                  = 0x00000003
+	SHTDN_REASON_MINOR_RECONFIG                 = 0x00000004
+	SHTDN_REASON_MINOR_HUNG                     = 0x00000005
+	SHTDN_REASON_MINOR_UNSTABLE                 = 0x00000006
+	SHTDN_REASON_MINOR_DISK                     = 0x00000007
+	SHTDN_REASON_MINOR_PROCESSOR                = 0x00000008
+	SHTDN_REASON_MINOR_NETWORKCARD              = 0x00000009
+	SHTDN_REASON_MINOR_POWER_SUPPLY             = 0x0000000a
+	SHTDN_REASON_MINOR_CORDUNPLUGGED            = 0x0000000b
+	SHTDN_REASON_MINOR_ENVIRONMENT              = 0x0000000c
+	SHTDN_REASON_MINOR_HARDWARE_DRIVER          = 0x0000000d
+	SHTDN_REASON_MINOR_OTHERDRIVER              = 0x0000000e
+	SHTDN_REASON_MINOR_BLUESCREEN               = 0x0000000F
+	SHTDN_REASON_MINOR_SERVICEPACK              = 0x00000010
+	SHTDN_REASON_MINOR_HOTFIX                   = 0x00000011
+	SHTDN_REASON_MINOR_SECURITYFIX              = 0x00000012
+	SHTDN_REASON_MINOR_SECURITY                 = 0x00000013
+	SHTDN_REASON_MINOR_NETWORK_CONNECTIVITY     = 0x00000014
+	SHTDN_REASON_MINOR_WMI                      = 0x00000015
+	SHTDN_REASON_MINOR_SERVICEPACK_UNINSTALL    = 0x00000016
+	SHTDN_REASON_MINOR_HOTFIX_UNINSTALL         = 0x00000017
+	SHTDN_REASON_MINOR_SECURITYFIX_UNINSTALL    = 0x00000018
+	SHTDN_REASON_MINOR_MMC                      = 0x00000019
+	SHTDN_REASON_MINOR_SYSTEMRESTORE            = 0x0000001a
+	SHTDN_REASON_MINOR_TERMSRV                  = 0x00000020
+	SHTDN_REASON_MINOR_DC_PROMOTION             = 0x00000021
+	SHTDN_REASON_MINOR_DC_DEMOTION              = 0x00000022
+	SHTDN_REASON_UNKNOWN                        = SHTDN_REASON_MINOR_NONE
+	SHTDN_REASON_LEGACY_API                     = SHTDN_REASON_MAJOR_LEGACY_API | SHTDN_REASON_FLAG_PLANNED
+	SHTDN_REASON_VALID_BIT_MASK                 = 0xc0ffffff
+
+	SHUTDOWN_NORETRY = 0x1
+)

windows/zsyscall_windows.go

@@ -234,6 +234,10 @@ var (
 	procSetVolumeLabelW                    = modkernel32.NewProc("SetVolumeLabelW")
 	procSetVolumeMountPointW               = modkernel32.NewProc("SetVolumeMountPointW")
 	procMessageBoxW                        = moduser32.NewProc("MessageBoxW")
+	procExitWindowsEx                      = moduser32.NewProc("ExitWindowsEx")
+	procInitiateSystemShutdownExW          = modadvapi32.NewProc("InitiateSystemShutdownExW")
+	procSetProcessShutdownParameters       = modkernel32.NewProc("SetProcessShutdownParameters")
+	procGetProcessShutdownParameters       = modkernel32.NewProc("GetProcessShutdownParameters")
 	procCLSIDFromString                    = modole32.NewProc("CLSIDFromString")
 	procStringFromGUID2                    = modole32.NewProc("StringFromGUID2")
 	procCoCreateGuid                       = modole32.NewProc("CoCreateGuid")
@@ -2584,6 +2588,66 @@ func MessageBox(hwnd Handle, text *uint16, caption *uint16, boxtype uint32) (ret
 	return
 }
 
+func ExitWindowsEx(flags uint32, reason uint32) (err error) {
+	r1, _, e1 := syscall.Syscall(procExitWindowsEx.Addr(), 2, uintptr(flags), uintptr(reason), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func InitiateSystemShutdownEx(machineName *uint16, message *uint16, timeout uint32, forceAppsClosed bool, rebootAfterShutdown bool, reason uint32) (err error) {
+	var _p0 uint32
+	if forceAppsClosed {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	var _p1 uint32
+	if rebootAfterShutdown {
+		_p1 = 1
+	} else {
+		_p1 = 0
+	}
+	r1, _, e1 := syscall.Syscall6(procInitiateSystemShutdownExW.Addr(), 6, uintptr(unsafe.Pointer(machineName)), uintptr(unsafe.Pointer(message)), uintptr(timeout), uintptr(_p0), uintptr(_p1), uintptr(reason))
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func SetProcessShutdownParameters(level uint32, flags uint32) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetProcessShutdownParameters.Addr(), 2, uintptr(level), uintptr(flags), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func GetProcessShutdownParameters(level *uint32, flags *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall(procGetProcessShutdownParameters.Addr(), 2, uintptr(unsafe.Pointer(level)), uintptr(unsafe.Pointer(flags)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func clsidFromString(lpsz *uint16, pclsid *GUID) (ret error) {
 	r0, _, _ := syscall.Syscall(procCLSIDFromString.Addr(), 2, uintptr(unsafe.Pointer(lpsz)), uintptr(unsafe.Pointer(pclsid)), 0)
 	if r0 != 0 {