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use std::ffi::OsStr;
use std::io;
use widestring::WideCString;
use winapi::shared::winerror::{ERROR_CALL_NOT_IMPLEMENTED, NO_ERROR};
use winapi::um::winsvc;
use service::{ServiceControl, ServiceStatus};
mod errors {
error_chain! {
errors {
InvalidServiceName {
description("Invalid service name")
}
}
foreign_links {
System(::std::io::Error);
}
}
}
pub use self::errors::*;
/// Struct that holds unique token for updating the status of the corresponding service.
#[derive(Debug, Clone, Copy)]
pub struct ServiceStatusHandle(winsvc::SERVICE_STATUS_HANDLE);
impl ServiceStatusHandle {
fn from_handle(handle: winsvc::SERVICE_STATUS_HANDLE) -> Self {
ServiceStatusHandle(handle)
}
/// Report the new service status to the system
pub fn set_service_status(&self, service_status: ServiceStatus) -> io::Result<()> {
let mut raw_service_status = service_status.to_raw();
let result = unsafe { winsvc::SetServiceStatus(self.0, &mut raw_service_status) };
if result == 0 {
Err(io::Error::last_os_error())
} else {
Ok(())
}
}
}
// Underlying SERVICE_STATUS_HANDLE is thread safe.
// See remarks section for more info:
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms686241(v=vs.85).aspx
unsafe impl Send for ServiceStatusHandle {}
/// Abstraction over the return value of service control handler.
/// The meaning of each of variants in this enum depends on the type of received event.
/// See the "Return value" section of corresponding MSDN article for more info:
/// https://msdn.microsoft.com/en-us/library/windows/desktop/ms683241(v=vs.85).aspx
#[derive(Debug)]
pub enum ServiceControlHandlerResult {
/// Either used to aknowledge the call or grant the permission in advanced events.
NoError,
/// The received event is not implemented.
NotImplemented,
/// This variant is used to deny permission and return the reason error code in advanced
/// events.
Other(u32),
}
impl ServiceControlHandlerResult {
pub fn to_raw(&self) -> u32 {
match *self {
ServiceControlHandlerResult::NoError => NO_ERROR,
ServiceControlHandlerResult::NotImplemented => ERROR_CALL_NOT_IMPLEMENTED,
ServiceControlHandlerResult::Other(code) => code,
}
}
}
/// Register a closure for receiving service events.
/// Returns `ServiceStatusHandle` that can be used to report the service status back to the system.
pub fn register_control_handler<
S: AsRef<OsStr>,
F: Fn(ServiceControl) -> ServiceControlHandlerResult + 'static,
>(
service_name: S,
event_handler: F,
) -> Result<ServiceStatusHandle> {
// Move closure data on heap.
// The Box<HandlerFn> is a trait object and is stored on stack at this point.
let heap_event_handler = Box::new(event_handler) as Box<HandlerFn>;
// Box again to move trait object to heap.
let boxed_event_handler: Box<Box<HandlerFn>> = Box::new(heap_event_handler);
// Important: leak the Box<Box<HandlerFn>> which will be released in `service_control_handler`.
let context = Box::into_raw(boxed_event_handler) as *mut ::std::os::raw::c_void;
let service_name =
WideCString::from_str(service_name).chain_err(|| ErrorKind::InvalidServiceName)?;
let status_handle = unsafe {
winsvc::RegisterServiceCtrlHandlerExW(
service_name.as_ptr(),
Some(service_control_handler),
context,
)
};
if status_handle.is_null() {
Err(io::Error::last_os_error().into())
} else {
Ok(ServiceStatusHandle::from_handle(status_handle))
}
}
/// Alias for control event handler closure.
type HandlerFn = Fn(ServiceControl) -> ServiceControlHandlerResult;
/// Static service control handler
#[allow(dead_code)]
extern "system" fn service_control_handler(
control: u32,
_event_type: u32,
_event_data: *mut ::std::os::raw::c_void,
context: *mut ::std::os::raw::c_void,
) -> u32 {
// Important: cast context to &mut Box<HandlerFn> without taking ownership.
let handler_fn = unsafe { &mut *(context as *mut Box<HandlerFn>) };
match ServiceControl::from_raw(control) {
Ok(service_control) => {
let return_code = ((handler_fn)(service_control)).to_raw();
// Important: release context upon Stop, Shutdown or Preshutdown at the end of the
// service lifecycle.
match service_control {
ServiceControl::Stop | ServiceControl::Shutdown | ServiceControl::Preshutdown => {
let _owned_boxed_handler: Box<Box<HandlerFn>> =
unsafe { Box::from_raw(context as *mut Box<HandlerFn>) };
}
_ => (),
};
return_code
}
// Report all unknown control commands as unimplemented
Err(_) => ServiceControlHandlerResult::NotImplemented.to_raw(),
}
}
|
