-
Notifications
You must be signed in to change notification settings - Fork 731
/
named_pipe.rs
993 lines (890 loc) · 34.5 KB
/
named_pipe.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
use std::ffi::OsStr;
use std::io::{self, Read, Write};
use std::os::windows::io::{AsRawHandle, FromRawHandle, RawHandle};
use std::sync::atomic::Ordering::{Relaxed, SeqCst};
use std::sync::atomic::{AtomicBool, AtomicUsize};
use std::sync::{Arc, Mutex};
use std::{fmt, mem, slice};
use windows_sys::Win32::Foundation::{
ERROR_BROKEN_PIPE, ERROR_IO_INCOMPLETE, ERROR_IO_PENDING, ERROR_NO_DATA, ERROR_PIPE_CONNECTED,
ERROR_PIPE_LISTENING, HANDLE, INVALID_HANDLE_VALUE,
};
use windows_sys::Win32::Storage::FileSystem::{
ReadFile, WriteFile, FILE_FLAG_FIRST_PIPE_INSTANCE, FILE_FLAG_OVERLAPPED, PIPE_ACCESS_DUPLEX,
};
use windows_sys::Win32::System::Pipes::{
ConnectNamedPipe, CreateNamedPipeW, DisconnectNamedPipe, PIPE_TYPE_BYTE,
PIPE_UNLIMITED_INSTANCES,
};
use windows_sys::Win32::System::IO::{
CancelIoEx, GetOverlappedResult, OVERLAPPED, OVERLAPPED_ENTRY,
};
use crate::event::Source;
use crate::sys::windows::iocp::{CompletionPort, CompletionStatus};
use crate::sys::windows::{Event, Handle, Overlapped};
use crate::Registry;
use crate::{Interest, Token};
/// Non-blocking windows named pipe.
///
/// This structure internally contains a `HANDLE` which represents the named
/// pipe, and also maintains state associated with the mio event loop and active
/// I/O operations that have been scheduled to translate IOCP to a readiness
/// model.
///
/// Note, IOCP is a *completion* based model whereas mio is a *readiness* based
/// model. To bridge this, `NamedPipe` performs internal buffering. Writes are
/// written to an internal buffer and the buffer is submitted to IOCP. IOCP
/// reads are submitted using internal buffers and `NamedPipe::read` reads from
/// this internal buffer.
///
/// # Trait implementations
///
/// The `Read` and `Write` traits are implemented for `NamedPipe` and for
/// `&NamedPipe`. This represents that a named pipe can be concurrently read and
/// written to and also can be read and written to at all. Typically a named
/// pipe needs to be connected to a client before it can be read or written,
/// however.
///
/// Note that for I/O operations on a named pipe to succeed then the named pipe
/// needs to be associated with an event loop. Until this happens all I/O
/// operations will return a "would block" error.
///
/// # Managing connections
///
/// The `NamedPipe` type supports a `connect` method to connect to a client and
/// a `disconnect` method to disconnect from that client. These two methods only
/// work once a named pipe is associated with an event loop.
///
/// The `connect` method will succeed asynchronously and a completion can be
/// detected once the object receives a writable notification.
///
/// # Named pipe clients
///
/// Currently to create a client of a named pipe server then you can use the
/// `OpenOptions` type in the standard library to create a `File` that connects
/// to a named pipe. Afterwards you can use the `into_raw_handle` method coupled
/// with the `NamedPipe::from_raw_handle` method to convert that to a named pipe
/// that can operate asynchronously. Don't forget to pass the
/// `FILE_FLAG_OVERLAPPED` flag when opening the `File`.
pub struct NamedPipe {
inner: Arc<Inner>,
}
/// # Notes
///
/// The memory layout of this structure must be fixed as the
/// `ptr_from_*_overlapped` methods depend on it, see the `ptr_from` test.
#[repr(C)]
struct Inner {
// NOTE: careful modifying the order of these three fields, the `ptr_from_*`
// methods depend on the layout!
connect: Overlapped,
read: Overlapped,
write: Overlapped,
// END NOTE.
handle: Handle,
connecting: AtomicBool,
io: Mutex<Io>,
pool: Mutex<BufferPool>,
}
impl Inner {
/// Converts a pointer to `Inner.connect` to a pointer to `Inner`.
///
/// # Unsafety
///
/// Caller must ensure `ptr` is pointing to `Inner.connect`.
unsafe fn ptr_from_conn_overlapped(ptr: *mut OVERLAPPED) -> *const Inner {
// `connect` is the first field, so the pointer are the same.
ptr.cast()
}
/// Same as [`ptr_from_conn_overlapped`] but for `Inner.read`.
unsafe fn ptr_from_read_overlapped(ptr: *mut OVERLAPPED) -> *const Inner {
// `read` is after `connect: Overlapped`.
(ptr as *mut Overlapped).wrapping_sub(1) as *const Inner
}
/// Same as [`ptr_from_conn_overlapped`] but for `Inner.write`.
unsafe fn ptr_from_write_overlapped(ptr: *mut OVERLAPPED) -> *const Inner {
// `read` is after `connect: Overlapped` and `read: Overlapped`.
(ptr as *mut Overlapped).wrapping_sub(2) as *const Inner
}
/// Issue a connection request with the specified overlapped operation.
///
/// This function will issue a request to connect a client to this server,
/// returning immediately after starting the overlapped operation.
///
/// If this function immediately succeeds then `Ok(true)` is returned. If
/// the overlapped operation is enqueued and pending, then `Ok(false)` is
/// returned. Otherwise an error is returned indicating what went wrong.
///
/// # Unsafety
///
/// This function is unsafe because the kernel requires that the
/// `overlapped` pointer is valid until the end of the I/O operation. The
/// kernel also requires that `overlapped` is unique for this I/O operation
/// and is not in use for any other I/O.
///
/// To safely use this function callers must ensure that this pointer is
/// valid until the I/O operation is completed, typically via completion
/// ports and waiting to receive the completion notification on the port.
pub unsafe fn connect_overlapped(&self, overlapped: *mut OVERLAPPED) -> io::Result<bool> {
if ConnectNamedPipe(self.handle.raw(), overlapped) != 0 {
return Ok(true);
}
let err = io::Error::last_os_error();
match err.raw_os_error().map(|e| e as u32) {
Some(ERROR_PIPE_CONNECTED) => Ok(true),
Some(ERROR_NO_DATA) => Ok(true),
Some(ERROR_IO_PENDING) => Ok(false),
_ => Err(err),
}
}
/// Disconnects this named pipe from any connected client.
pub fn disconnect(&self) -> io::Result<()> {
if unsafe { DisconnectNamedPipe(self.handle.raw()) } == 0 {
Err(io::Error::last_os_error())
} else {
Ok(())
}
}
/// Issues an overlapped read operation to occur on this pipe.
///
/// This function will issue an asynchronous read to occur in an overlapped
/// fashion, returning immediately. The `buf` provided will be filled in
/// with data and the request is tracked by the `overlapped` function
/// provided.
///
/// If the operation succeeds immediately, `Ok(Some(n))` is returned where
/// `n` is the number of bytes read. If an asynchronous operation is
/// enqueued, then `Ok(None)` is returned. Otherwise if an error occurred
/// it is returned.
///
/// When this operation completes (or if it completes immediately), another
/// mechanism must be used to learn how many bytes were transferred (such as
/// looking at the filed in the IOCP status message).
///
/// # Unsafety
///
/// This function is unsafe because the kernel requires that the `buf` and
/// `overlapped` pointers to be valid until the end of the I/O operation.
/// The kernel also requires that `overlapped` is unique for this I/O
/// operation and is not in use for any other I/O.
///
/// To safely use this function callers must ensure that the pointers are
/// valid until the I/O operation is completed, typically via completion
/// ports and waiting to receive the completion notification on the port.
pub unsafe fn read_overlapped(
&self,
buf: &mut [u8],
overlapped: *mut OVERLAPPED,
) -> io::Result<Option<usize>> {
let len = std::cmp::min(buf.len(), u32::MAX as usize) as u32;
let res = ReadFile(
self.handle.raw(),
buf.as_mut_ptr() as *mut _,
len,
std::ptr::null_mut(),
overlapped,
);
if res == 0 {
let err = io::Error::last_os_error();
if err.raw_os_error() != Some(ERROR_IO_PENDING as i32) {
return Err(err);
}
}
let mut bytes = 0;
let res = GetOverlappedResult(self.handle.raw(), overlapped, &mut bytes, 0);
if res == 0 {
let err = io::Error::last_os_error();
if err.raw_os_error() == Some(ERROR_IO_INCOMPLETE as i32) {
Ok(None)
} else {
Err(err)
}
} else {
Ok(Some(bytes as usize))
}
}
/// Issues an overlapped write operation to occur on this pipe.
///
/// This function will issue an asynchronous write to occur in an overlapped
/// fashion, returning immediately. The `buf` provided will be filled in
/// with data and the request is tracked by the `overlapped` function
/// provided.
///
/// If the operation succeeds immediately, `Ok(Some(n))` is returned where
/// `n` is the number of bytes written. If an asynchronous operation is
/// enqueued, then `Ok(None)` is returned. Otherwise if an error occurred
/// it is returned.
///
/// When this operation completes (or if it completes immediately), another
/// mechanism must be used to learn how many bytes were transferred (such as
/// looking at the filed in the IOCP status message).
///
/// # Unsafety
///
/// This function is unsafe because the kernel requires that the `buf` and
/// `overlapped` pointers to be valid until the end of the I/O operation.
/// The kernel also requires that `overlapped` is unique for this I/O
/// operation and is not in use for any other I/O.
///
/// To safely use this function callers must ensure that the pointers are
/// valid until the I/O operation is completed, typically via completion
/// ports and waiting to receive the completion notification on the port.
pub unsafe fn write_overlapped(
&self,
buf: &[u8],
overlapped: *mut OVERLAPPED,
) -> io::Result<Option<usize>> {
let len = std::cmp::min(buf.len(), u32::MAX as usize) as u32;
let res = WriteFile(
self.handle.raw(),
buf.as_ptr() as *const _,
len,
std::ptr::null_mut(),
overlapped,
);
if res == 0 {
let err = io::Error::last_os_error();
if err.raw_os_error() != Some(ERROR_IO_PENDING as i32) {
return Err(err);
}
}
let mut bytes = 0;
let res = GetOverlappedResult(self.handle.raw(), overlapped, &mut bytes, 0);
if res == 0 {
let err = io::Error::last_os_error();
if err.raw_os_error() == Some(ERROR_IO_INCOMPLETE as i32) {
Ok(None)
} else {
Err(err)
}
} else {
Ok(Some(bytes as usize))
}
}
/// Calls the `GetOverlappedResult` function to get the result of an
/// overlapped operation for this handle.
///
/// This function takes the `OVERLAPPED` argument which must have been used
/// to initiate an overlapped I/O operation, and returns either the
/// successful number of bytes transferred during the operation or an error
/// if one occurred.
///
/// # Unsafety
///
/// This function is unsafe as `overlapped` must have previously been used
/// to execute an operation for this handle, and it must also be a valid
/// pointer to an `Overlapped` instance.
#[inline]
unsafe fn result(&self, overlapped: *mut OVERLAPPED) -> io::Result<usize> {
let mut transferred = 0;
let r = GetOverlappedResult(self.handle.raw(), overlapped, &mut transferred, 0);
if r == 0 {
Err(io::Error::last_os_error())
} else {
Ok(transferred as usize)
}
}
}
#[test]
fn ptr_from() {
use std::mem::ManuallyDrop;
use std::ptr;
let pipe = unsafe { ManuallyDrop::new(NamedPipe::from_raw_handle(ptr::null_mut())) };
let inner: &Inner = &pipe.inner;
assert_eq!(
inner as *const Inner,
unsafe { Inner::ptr_from_conn_overlapped(&inner.connect as *const _ as *mut OVERLAPPED) },
"`ptr_from_conn_overlapped` incorrect"
);
assert_eq!(
inner as *const Inner,
unsafe { Inner::ptr_from_read_overlapped(&inner.read as *const _ as *mut OVERLAPPED) },
"`ptr_from_read_overlapped` incorrect"
);
assert_eq!(
inner as *const Inner,
unsafe { Inner::ptr_from_write_overlapped(&inner.write as *const _ as *mut OVERLAPPED) },
"`ptr_from_write_overlapped` incorrect"
);
}
struct Io {
// Uniquely identifies the selector associated with this named pipe
cp: Option<Arc<CompletionPort>>,
// Token used to identify events
token: Option<Token>,
read: State,
write: State,
connect_error: Option<io::Error>,
}
#[derive(Debug)]
enum State {
None,
Pending(Vec<u8>, usize),
Ok(Vec<u8>, usize),
Err(io::Error),
}
// Odd tokens are for named pipes
static NEXT_TOKEN: AtomicUsize = AtomicUsize::new(1);
fn would_block() -> io::Error {
io::ErrorKind::WouldBlock.into()
}
impl NamedPipe {
/// Creates a new named pipe at the specified `addr` given a "reasonable
/// set" of initial configuration options.
pub fn new<A: AsRef<OsStr>>(addr: A) -> io::Result<NamedPipe> {
use std::os::windows::ffi::OsStrExt;
let name: Vec<_> = addr.as_ref().encode_wide().chain(Some(0)).collect();
// Safety: syscall
let h = unsafe {
CreateNamedPipeW(
name.as_ptr(),
PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE | FILE_FLAG_OVERLAPPED,
PIPE_TYPE_BYTE,
PIPE_UNLIMITED_INSTANCES,
65536,
65536,
0,
std::ptr::null_mut(),
)
};
if h == INVALID_HANDLE_VALUE {
Err(io::Error::last_os_error())
} else {
// Safety: nothing actually unsafe about this. The trait fn includes
// `unsafe`.
Ok(unsafe { Self::from_raw_handle(h as RawHandle) })
}
}
/// Attempts to call `ConnectNamedPipe`, if possible.
///
/// This function will attempt to connect this pipe to a client in an
/// asynchronous fashion. If the function immediately establishes a
/// connection to a client then `Ok(())` is returned. Otherwise if a
/// connection attempt was issued and is now in progress then a "would
/// block" error is returned.
///
/// When the connection is finished then this object will be flagged as
/// being ready for a write, or otherwise in the writable state.
///
/// # Errors
///
/// This function will return a "would block" error if the pipe has not yet
/// been registered with an event loop, if the connection operation has
/// previously been issued but has not yet completed, or if the connect
/// itself was issued and didn't finish immediately.
///
/// Normal I/O errors from the call to `ConnectNamedPipe` are returned
/// immediately.
pub fn connect(&self) -> io::Result<()> {
// "Acquire the connecting lock" or otherwise just make sure we're the
// only operation that's using the `connect` overlapped instance.
if self.inner.connecting.swap(true, SeqCst) {
return Err(would_block());
}
// Now that we've flagged ourselves in the connecting state, issue the
// connection attempt. Afterwards interpret the return value and set
// internal state accordingly.
let res = unsafe {
let overlapped = self.inner.connect.as_ptr() as *mut _;
self.inner.connect_overlapped(overlapped)
};
match res {
// The connection operation finished immediately, so let's schedule
// reads/writes and such.
Ok(true) => {
self.inner.connecting.store(false, SeqCst);
Inner::post_register(&self.inner, None);
Ok(())
}
// If the overlapped operation was successful and didn't finish
// immediately then we forget a copy of the arc we hold
// internally. This ensures that when the completion status comes
// in for the I/O operation finishing it'll have a reference
// associated with it and our data will still be valid. The
// `connect_done` function will "reify" this forgotten pointer to
// drop the refcount on the other side.
Ok(false) => {
mem::forget(self.inner.clone());
Err(would_block())
}
Err(e) => {
self.inner.connecting.store(false, SeqCst);
Err(e)
}
}
}
/// Takes any internal error that has happened after the last I/O operation
/// which hasn't been retrieved yet.
///
/// This is particularly useful when detecting failed attempts to `connect`.
/// After a completed `connect` flags this pipe as writable then callers
/// must invoke this method to determine whether the connection actually
/// succeeded. If this function returns `None` then a client is connected,
/// otherwise it returns an error of what happened and a client shouldn't be
/// connected.
pub fn take_error(&self) -> io::Result<Option<io::Error>> {
Ok(self.inner.io.lock().unwrap().connect_error.take())
}
/// Disconnects this named pipe from a connected client.
///
/// This function will disconnect the pipe from a connected client, if any,
/// transitively calling the `DisconnectNamedPipe` function.
///
/// After a `disconnect` is issued, then a `connect` may be called again to
/// connect to another client.
pub fn disconnect(&self) -> io::Result<()> {
self.inner.disconnect()
}
}
impl FromRawHandle for NamedPipe {
unsafe fn from_raw_handle(handle: RawHandle) -> NamedPipe {
NamedPipe {
inner: Arc::new(Inner {
handle: Handle::new(handle as HANDLE),
connect: Overlapped::new(connect_done),
connecting: AtomicBool::new(false),
read: Overlapped::new(read_done),
write: Overlapped::new(write_done),
io: Mutex::new(Io {
cp: None,
token: None,
read: State::None,
write: State::None,
connect_error: None,
}),
pool: Mutex::new(BufferPool::with_capacity(2)),
}),
}
}
}
impl Read for NamedPipe {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
<&NamedPipe as Read>::read(&mut &*self, buf)
}
}
impl Write for NamedPipe {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
<&NamedPipe as Write>::write(&mut &*self, buf)
}
fn flush(&mut self) -> io::Result<()> {
<&NamedPipe as Write>::flush(&mut &*self)
}
}
impl<'a> Read for &'a NamedPipe {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let mut state = self.inner.io.lock().unwrap();
if state.token.is_none() {
return Err(would_block());
}
match mem::replace(&mut state.read, State::None) {
// In theory not possible with `token` checked above,
// but return would block for now.
State::None => Err(would_block()),
// A read is in flight, still waiting for it to finish
State::Pending(buf, amt) => {
state.read = State::Pending(buf, amt);
Err(would_block())
}
// We previously read something into `data`, try to copy out some
// data. If we copy out all the data schedule a new read and
// otherwise store the buffer to get read later.
State::Ok(data, cur) => {
let n = {
let mut remaining = &data[cur..];
remaining.read(buf)?
};
let next = cur + n;
if next != data.len() {
state.read = State::Ok(data, next);
} else {
self.inner.put_buffer(data);
Inner::schedule_read(&self.inner, &mut state, None);
}
Ok(n)
}
// Looks like an in-flight read hit an error, return that here while
// we schedule a new one.
State::Err(e) => {
Inner::schedule_read(&self.inner, &mut state, None);
if e.raw_os_error() == Some(ERROR_BROKEN_PIPE as i32) {
Ok(0)
} else {
Err(e)
}
}
}
}
}
impl<'a> Write for &'a NamedPipe {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
// Make sure there's no writes pending
let mut io = self.inner.io.lock().unwrap();
if io.token.is_none() {
return Err(would_block());
}
match io.write {
State::None => {}
State::Err(_) => match mem::replace(&mut io.write, State::None) {
State::Err(e) => return Err(e),
// `io` is locked, so this branch is unreachable
_ => unreachable!(),
},
// any other state should be handled in `write_done`
_ => {
return Err(would_block());
}
}
// Move `buf` onto the heap and fire off the write
let mut owned_buf = self.inner.get_buffer();
owned_buf.extend(buf);
match Inner::maybe_schedule_write(&self.inner, owned_buf, 0, &mut io)? {
// Some bytes are written immediately
Some(n) => Ok(n),
// Write operation is anqueued for whole buffer
None => Ok(buf.len()),
}
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
impl Source for NamedPipe {
fn register(&mut self, registry: &Registry, token: Token, _: Interest) -> io::Result<()> {
let mut io = self.inner.io.lock().unwrap();
io.check_association(registry, false)?;
if io.token.is_some() {
return Err(io::Error::new(
io::ErrorKind::AlreadyExists,
"I/O source already registered with a `Registry`",
));
}
if io.cp.is_none() {
let selector = registry.selector();
io.cp = Some(selector.clone_port());
let inner_token = NEXT_TOKEN.fetch_add(2, Relaxed) + 2;
selector.inner.cp.add_handle(inner_token, self)?;
}
io.token = Some(token);
drop(io);
Inner::post_register(&self.inner, None);
Ok(())
}
fn reregister(&mut self, registry: &Registry, token: Token, _: Interest) -> io::Result<()> {
let mut io = self.inner.io.lock().unwrap();
io.check_association(registry, true)?;
io.token = Some(token);
drop(io);
Inner::post_register(&self.inner, None);
Ok(())
}
fn deregister(&mut self, registry: &Registry) -> io::Result<()> {
let mut io = self.inner.io.lock().unwrap();
io.check_association(registry, true)?;
if io.token.is_none() {
return Err(io::Error::new(
io::ErrorKind::NotFound,
"I/O source not registered with `Registry`",
));
}
io.token = None;
Ok(())
}
}
impl AsRawHandle for NamedPipe {
fn as_raw_handle(&self) -> RawHandle {
self.inner.handle.raw() as RawHandle
}
}
impl fmt::Debug for NamedPipe {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.handle.fmt(f)
}
}
impl Drop for NamedPipe {
fn drop(&mut self) {
// Cancel pending reads/connects, but don't cancel writes to ensure that
// everything is flushed out.
unsafe {
if self.inner.connecting.load(SeqCst) {
drop(cancel(&self.inner.handle, &self.inner.connect));
}
let io = self.inner.io.lock().unwrap();
if let State::Pending(..) = io.read {
drop(cancel(&self.inner.handle, &self.inner.read));
}
}
}
}
impl Inner {
/// Schedules a read to happen in the background, executing an overlapped
/// operation.
///
/// This function returns `true` if a normal error happens or if the read
/// is scheduled in the background. If the pipe is no longer connected
/// (ERROR_PIPE_LISTENING) then `false` is returned and no read is
/// scheduled.
fn schedule_read(me: &Arc<Inner>, io: &mut Io, events: Option<&mut Vec<Event>>) -> bool {
// Check to see if a read is already scheduled/completed
match io.read {
State::None => {}
_ => return true,
}
// Allocate a buffer and schedule the read.
let mut buf = me.get_buffer();
let e = unsafe {
let overlapped = me.read.as_ptr() as *mut _;
let slice = slice::from_raw_parts_mut(buf.as_mut_ptr(), buf.capacity());
me.read_overlapped(slice, overlapped)
};
match e {
// See `NamedPipe::connect` above for the rationale behind `forget`
Ok(_) => {
io.read = State::Pending(buf, 0); // 0 is ignored on read side
mem::forget(me.clone());
true
}
// If ERROR_PIPE_LISTENING happens then it's not a real read error,
// we just need to wait for a connect.
Err(ref e) if e.raw_os_error() == Some(ERROR_PIPE_LISTENING as i32) => false,
// If some other error happened, though, we're now readable to give
// out the error.
Err(e) => {
io.read = State::Err(e);
io.notify_readable(events);
true
}
}
}
/// Maybe schedules overlapped write operation.
///
/// * `None` means that overlapped operation was enqueued
/// * `Some(n)` means that `n` bytes was immediately written.
/// Note, that `write_done` will fire anyway to clean up the state.
fn maybe_schedule_write(
me: &Arc<Inner>,
buf: Vec<u8>,
pos: usize,
io: &mut Io,
) -> io::Result<Option<usize>> {
// Very similar to `schedule_read` above, just done for the write half.
let e = unsafe {
let overlapped = me.write.as_ptr() as *mut _;
me.write_overlapped(&buf[pos..], overlapped)
};
// See `connect` above for the rationale behind `forget`
match e {
// `n` bytes are written immediately
Ok(Some(n)) => {
io.write = State::Ok(buf, pos);
mem::forget(me.clone());
Ok(Some(n))
}
// write operation is enqueued
Ok(None) => {
io.write = State::Pending(buf, pos);
mem::forget(me.clone());
Ok(None)
}
Err(e) => Err(e),
}
}
fn schedule_write(
me: &Arc<Inner>,
buf: Vec<u8>,
pos: usize,
io: &mut Io,
events: Option<&mut Vec<Event>>,
) {
match Inner::maybe_schedule_write(me, buf, pos, io) {
Ok(Some(_)) => {
// immediate result will be handled in `write_done`,
// so we'll reinterpret the `Ok` state
let state = mem::replace(&mut io.write, State::None);
io.write = match state {
State::Ok(buf, pos) => State::Pending(buf, pos),
// io is locked, so this branch is unreachable
_ => unreachable!(),
};
mem::forget(me.clone());
}
Ok(None) => (),
Err(e) => {
io.write = State::Err(e);
io.notify_writable(events);
}
}
}
fn post_register(me: &Arc<Inner>, mut events: Option<&mut Vec<Event>>) {
let mut io = me.io.lock().unwrap();
#[allow(clippy::needless_option_as_deref)]
if Inner::schedule_read(me, &mut io, events.as_deref_mut()) {
if let State::None = io.write {
io.notify_writable(events);
}
}
}
fn get_buffer(&self) -> Vec<u8> {
self.pool.lock().unwrap().get(4 * 1024)
}
fn put_buffer(&self, buf: Vec<u8>) {
self.pool.lock().unwrap().put(buf)
}
}
unsafe fn cancel(handle: &Handle, overlapped: &Overlapped) -> io::Result<()> {
let ret = CancelIoEx(handle.raw(), overlapped.as_ptr());
// `CancelIoEx` returns 0 on error:
// https://docs.microsoft.com/en-us/windows/win32/fileio/cancelioex-func
if ret == 0 {
Err(io::Error::last_os_error())
} else {
Ok(())
}
}
fn connect_done(status: &OVERLAPPED_ENTRY, events: Option<&mut Vec<Event>>) {
let status = CompletionStatus::from_entry(status);
// Acquire the `Arc<Inner>`. Note that we should be guaranteed that
// the refcount is available to us due to the `mem::forget` in
// `connect` above.
let me = unsafe { Arc::from_raw(Inner::ptr_from_conn_overlapped(status.overlapped())) };
// Flag ourselves as no longer using the `connect` overlapped instances.
let prev = me.connecting.swap(false, SeqCst);
assert!(prev, "NamedPipe was not previously connecting");
// Stash away our connect error if one happened
debug_assert_eq!(status.bytes_transferred(), 0);
unsafe {
match me.result(status.overlapped()) {
Ok(n) => debug_assert_eq!(n, 0),
Err(e) => me.io.lock().unwrap().connect_error = Some(e),
}
}
// We essentially just finished a registration, so kick off a
// read and register write readiness.
Inner::post_register(&me, events);
}
fn read_done(status: &OVERLAPPED_ENTRY, events: Option<&mut Vec<Event>>) {
let status = CompletionStatus::from_entry(status);
// Acquire the `FromRawArc<Inner>`. Note that we should be guaranteed that
// the refcount is available to us due to the `mem::forget` in
// `schedule_read` above.
let me = unsafe { Arc::from_raw(Inner::ptr_from_read_overlapped(status.overlapped())) };
// Move from the `Pending` to `Ok` state.
let mut io = me.io.lock().unwrap();
let mut buf = match mem::replace(&mut io.read, State::None) {
State::Pending(buf, _) => buf,
_ => unreachable!(),
};
unsafe {
match me.result(status.overlapped()) {
Ok(n) => {
debug_assert_eq!(status.bytes_transferred() as usize, n);
buf.set_len(status.bytes_transferred() as usize);
io.read = State::Ok(buf, 0);
}
Err(e) => {
debug_assert_eq!(status.bytes_transferred(), 0);
io.read = State::Err(e);
}
}
}
// Flag our readiness that we've got data.
io.notify_readable(events);
}
fn write_done(status: &OVERLAPPED_ENTRY, events: Option<&mut Vec<Event>>) {
let status = CompletionStatus::from_entry(status);
// Acquire the `Arc<Inner>`. Note that we should be guaranteed that
// the refcount is available to us due to the `mem::forget` in
// `schedule_write` above.
let me = unsafe { Arc::from_raw(Inner::ptr_from_write_overlapped(status.overlapped())) };
// Make the state change out of `Pending`. If we wrote the entire buffer
// then we're writable again and otherwise we schedule another write.
let mut io = me.io.lock().unwrap();
let (buf, pos) = match mem::replace(&mut io.write, State::None) {
// `Ok` here means, that the operation was completed immediately
// `bytes_transferred` is already reported to a client
State::Ok(..) => {
io.notify_writable(events);
return;
}
State::Pending(buf, pos) => (buf, pos),
_ => unreachable!(),
};
unsafe {
match me.result(status.overlapped()) {
Ok(n) => {
debug_assert_eq!(status.bytes_transferred() as usize, n);
let new_pos = pos + (status.bytes_transferred() as usize);
if new_pos == buf.len() {
me.put_buffer(buf);
io.notify_writable(events);
} else {
Inner::schedule_write(&me, buf, new_pos, &mut io, events);
}
}
Err(e) => {
debug_assert_eq!(status.bytes_transferred(), 0);
io.write = State::Err(e);
io.notify_writable(events);
}
}
}
}
impl Io {
fn check_association(&self, registry: &Registry, required: bool) -> io::Result<()> {
match self.cp {
Some(ref cp) if !registry.selector().same_port(cp) => Err(io::Error::new(
io::ErrorKind::AlreadyExists,
"I/O source already registered with a different `Registry`",
)),
None if required => Err(io::Error::new(
io::ErrorKind::NotFound,
"I/O source not registered with `Registry`",
)),
_ => Ok(()),
}
}
fn notify_readable(&self, events: Option<&mut Vec<Event>>) {
if let Some(token) = self.token {
let mut ev = Event::new(token);
ev.set_readable();
if let Some(events) = events {
events.push(ev);
} else {
let _ = self.cp.as_ref().unwrap().post(ev.to_completion_status());
}
}
}
fn notify_writable(&self, events: Option<&mut Vec<Event>>) {
if let Some(token) = self.token {
let mut ev = Event::new(token);
ev.set_writable();
if let Some(events) = events {
events.push(ev);
} else {
let _ = self.cp.as_ref().unwrap().post(ev.to_completion_status());
}
}
}
}
struct BufferPool {
pool: Vec<Vec<u8>>,
}
impl BufferPool {
fn with_capacity(cap: usize) -> BufferPool {
BufferPool {
pool: Vec::with_capacity(cap),
}
}
fn get(&mut self, default_cap: usize) -> Vec<u8> {
self.pool
.pop()
.unwrap_or_else(|| Vec::with_capacity(default_cap))
}
fn put(&mut self, mut buf: Vec<u8>) {
if self.pool.len() < self.pool.capacity() {
unsafe {
buf.set_len(0);
}
self.pool.push(buf);
}
}
}