commit 8a69140bde95ee56138cac9d942a13d472e4188d
author Jason A. Donenfeld <Jason@zx2c4.com> Sun Sep 15 11:50:40 2019 -0600
committer Jason A. Donenfeld <Jason@zx2c4.com> Mon Sep 16 16:59:10 2019 +0000
tree ec8007b67578c7fd994dd02cfafe7329769119c5
parent 1a3b71a79e4aff00d87e69e0744746d7d67a3f8f

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>