stacks_common/util/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
/*
copyright: (c) 2013-2020 by Blockstack PBC, a public benefit corporation.
This file is part of Blockstack.
Blockstack is free software. You may redistribute or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License or
(at your option) any later version.
Blockstack is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY, including without the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Blockstack. If not, see <http://www.gnu.org/licenses/>.
*/
use std::io;
use std::io::{Read, Write};
use std::sync::mpsc::{sync_channel, Receiver, SyncSender, TryRecvError, TrySendError};
/// Inter-thread pipe for streaming messages, built on channels.
/// Used mainly in conjunction with networking.
/// * The read endpoint lives inside the connection, and will consume data from another thread to
/// be sent out on the network.
/// * The write endpoint gets fed into calls to consensus_serialize(), to be sent out on the
/// network.
#[derive(Debug)]
pub struct PipeRead {
input: Receiver<Vec<u8>>,
buf: Vec<u8>,
i: usize,
block: bool,
}
#[derive(Debug)]
pub struct PipeWrite {
output: SyncSender<Vec<u8>>,
buf: Option<Vec<u8>>,
}
pub struct Pipe {}
#[allow(clippy::new_ret_no_self)]
impl Pipe {
pub fn new() -> (PipeRead, PipeWrite) {
let (send, recv) = sync_channel(1);
(PipeRead::new(recv), PipeWrite::new(send))
}
}
impl PipeRead {
fn new(input: Receiver<Vec<u8>>) -> PipeRead {
PipeRead {
input,
buf: vec![],
i: 0,
block: true,
}
}
pub fn set_nonblocking(&mut self, flag: bool) {
self.block = !flag;
}
fn drain_buf(&mut self, buf: &mut [u8]) -> usize {
if self.i < self.buf.len() {
// have buffered data from the last read
let buf_available = &self.buf[self.i..];
let to_copy = if buf_available.len() < buf.len() {
buf_available.len()
} else {
buf.len()
};
if to_copy > 0 {
trace!(
"Pipe read {} bytes from buffer [{}...]",
to_copy,
buf_available[0]
);
}
buf[..to_copy].copy_from_slice(&buf_available[..to_copy]);
self.i += to_copy;
if self.i >= self.buf.len() {
trace!("Pipe read buffer drained from {} bytes", self.i);
// drained!
self.buf.clear();
self.i = 0;
}
to_copy
} else {
0
}
}
fn fill_buf(&mut self, buf: &mut [u8]) -> io::Result<usize> {
assert_eq!(self.buf.len(), 0);
assert_eq!(self.i, 0);
let mut copied = 0;
let mut disconnected = false;
let mut blocked = false;
while copied < buf.len() && !disconnected && !blocked {
let next_bytes = match self.input.try_recv() {
Ok(bytes) => {
trace!("Pipe received {} bytes", bytes.len());
bytes
}
Err(tre) => match tre {
TryRecvError::Empty => {
// no data yet
if self.block {
match self.input.recv() {
Ok(bytes) => bytes,
Err(_e) => {
// dead
trace!("Pipe read disconnect on blocking read ({})", _e);
disconnected = true;
vec![]
}
}
} else {
trace!("Pipe read {} bytes before blocking", copied);
blocked = true;
vec![]
}
}
TryRecvError::Disconnected => {
// dead
trace!("Pipe read disconnect");
disconnected = true;
vec![]
}
},
};
let remaining = buf[copied..].len();
let to_copy = if next_bytes.len() < remaining {
next_bytes.len()
} else {
remaining
};
trace!(
"Pipe read copied {} bytes from channel ({} total)",
to_copy,
copied
);
buf[copied..(copied + to_copy)].copy_from_slice(&next_bytes[0..to_copy]);
copied += to_copy;
// buffer remainder
if copied == buf.len() && to_copy < next_bytes.len() {
trace!(
"Pipe read buffered {} bytes [{}...]",
&next_bytes[to_copy..].len(),
next_bytes[to_copy]
);
self.buf.extend_from_slice(&next_bytes[to_copy..]);
}
}
if disconnected && copied == 0 {
// out of data, and will never get more
return Err(io::Error::from(io::ErrorKind::BrokenPipe));
}
if blocked && copied == 0 {
return Err(io::Error::from(io::ErrorKind::WouldBlock));
}
Ok(copied)
}
}
impl PipeWrite {
fn new(output: SyncSender<Vec<u8>>) -> PipeWrite {
PipeWrite { output, buf: None }
}
fn write_or_buffer(&mut self, buf: &[u8]) -> io::Result<usize> {
if buf.len() == 0 {
return Ok(0);
}
// add buf to our internal buffer...
if self.buf.is_none() {
let data = buf.to_vec();
self.buf = Some(data);
} else {
let mut tmp = self.buf.take().unwrap(); // safe due to check above
tmp.extend_from_slice(buf);
self.buf = Some(tmp);
}
// will be Some() either way
let data = self.buf.take().unwrap();
let _len = data.len();
// ...and try to send the whole thing over
match self.output.try_send(data) {
Ok(_) => {
trace!("Pipe wrote {} bytes", _len);
}
Err(TrySendError::Full(data)) => {
trace!("Pipe write buffered {} bytes", data.len());
self.buf = Some(data);
}
Err(TrySendError::Disconnected(_)) => {
// will never succeed
return Err(io::Error::from(io::ErrorKind::BrokenPipe));
}
}
// either way we consumed it
Ok(buf.len())
}
/// How many bytes are pending?
pub fn pending(&self) -> usize {
self.buf.as_ref().map(|b| b.len()).unwrap_or(0)
}
/// Try and flush all data to the reader.
/// Return True if we succeeded; False if not.
pub fn try_flush(&mut self) -> io::Result<bool> {
let data = self.buf.take();
if let Some(bytes) = data {
match self.output.try_send(bytes) {
Err(TrySendError::Full(ret_bytes)) => {
// try again
self.buf = Some(ret_bytes);
Ok(false)
}
Err(TrySendError::Disconnected(_)) => {
// broken
Err(io::Error::from(io::ErrorKind::BrokenPipe))
}
Ok(_) => {
// sent!
Ok(true)
}
}
} else {
// done!
Ok(true)
}
}
}
impl Read for PipeRead {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let copied = self.drain_buf(buf);
if copied == buf.len() {
trace!(
"Read {} bytes total from buffer (pipe channel not used)",
copied
);
return Ok(copied);
}
let filled = match self.fill_buf(&mut buf[copied..]) {
Ok(cnt) => cnt,
Err(e) => match e.kind() {
io::ErrorKind::BrokenPipe | io::ErrorKind::WouldBlock => {
if copied > 0 {
// if we get EPIPE or EWOULDBLOCK when getting data from the writer, but we hit the
// buffer, then this isn't a failure.
0
} else {
trace!("Error reading from pipe: {:?}", &e);
return Err(e);
}
}
_ => {
trace!("Error reading from pipe: {:?}", &e);
return Err(e);
}
},
};
trace!(
"Read {} bytes total from pipe channel and buffer",
copied + filled
);
Ok(copied + filled)
}
}
impl Write for PipeWrite {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.write_or_buffer(buf)
}
fn flush(&mut self) -> io::Result<()> {
if let Some(bytes) = self.buf.take() {
let _len = bytes.len();
self.output
.send(bytes)
.map_err(|_e| io::Error::from(io::ErrorKind::BrokenPipe))?;
trace!("Pipe wrote {} bytes on flush", _len);
}
Ok(())
}
}
#[cfg(test)]
mod test {
use std::io::prelude::*;
use std::io::{Read, Write};
use std::{io, thread};
use rand;
use rand::RngCore;
use super::*;
use crate::util::*;
#[test]
fn test_connection_pipe_oneshot() {
let tests = vec![
// .0: the list of vecs to send to the writer
// .1: the number of bytes to read each time
// .2: the expected Result<num-bytes-total, error-encountered>
(vec![0, 1, 2], vec![3], vec![Ok(3)]),
(vec![0, 1, 2], vec![1, 2], vec![Ok(1), Ok(2)]),
(vec![0, 1, 2], vec![1, 1, 1], vec![Ok(1), Ok(1), Ok(1)]),
(vec![0, 1, 2], vec![0, 3], vec![Ok(0), Ok(3)]),
(vec![0, 1, 2], vec![4], vec![Ok(3)]),
(
vec![0, 1, 2],
vec![4, 1],
vec![Ok(3), Err(io::Error::from(io::ErrorKind::WouldBlock))],
),
];
for (send_bytes, recv_list, outputs) in tests.iter() {
test_debug!(
"send {:?}, recv {:?}, expect {:?}",
send_bytes,
recv_list,
outputs
);
assert_eq!(recv_list.len(), outputs.len());
let (mut pipe_read, mut pipe_write) = Pipe::new();
let mut recv_buf = vec![];
let expected_recv_buf = send_bytes.clone();
pipe_read.set_nonblocking(true);
let _ = pipe_write.write(&send_bytes[..]).unwrap();
for i in 0..recv_list.len() {
let mut buf = vec![0u8; recv_list[i]];
match pipe_read.read(&mut buf) {
Ok(num_bytes) => {
assert!(
outputs[i].is_ok(),
"Expected {:?}, got Ok({})",
&outputs[i],
num_bytes
);
let num_bytes_expected = outputs[i].as_ref().ok().unwrap();
assert_eq!(
num_bytes, *num_bytes_expected,
"Expected {}, got {}",
num_bytes, num_bytes_expected
);
recv_buf.extend_from_slice(&buf[0..num_bytes]);
}
Err(e) => {
assert!(
outputs[i].is_err(),
"Expected {:?}, got Err({:?})",
&outputs[i],
&e
);
let expected_output_err = outputs[i].as_ref().err().unwrap();
assert_eq!(
expected_output_err.kind(),
e.kind(),
"I/O error mismatch: expected {:?}, got {:?}",
e.kind(),
expected_output_err.kind()
);
}
}
}
assert_eq!(recv_buf, expected_recv_buf);
}
}
#[test]
fn test_connection_pipe_producer_consumer() {
let mut buf = vec![0; 1048576];
let mut rng = rand::thread_rng();
rng.fill_bytes(&mut buf);
let buf_compare = buf.clone(); // for use in the consumer
let (mut pipe_read, mut pipe_write) = Pipe::new();
pipe_read.set_nonblocking(false);
let producer = thread::spawn(move || {
let mut rng = rand::thread_rng();
let mut i = 0;
let mut broken_pipe = false;
while i < buf.len() && !broken_pipe {
let mut span = (rng.next_u32() % 4096) as usize;
if i + span > buf.len() {
span = buf.len() - i;
}
let nw = match pipe_write.write(&buf[i..(i + span)]) {
Ok(sz) => sz,
Err(e) => match e.kind() {
io::ErrorKind::BrokenPipe => {
broken_pipe = true;
0
}
_ => {
assert!(false, "unwrapped err: {:?}", &e);
unreachable!();
}
},
};
i += span;
}
let _ = pipe_write.flush();
if broken_pipe {
assert_eq!(i, buf.len());
}
test_debug!("producer exit; wrote {} bytes", i);
});
let consumer = thread::spawn(move || {
let mut rng = rand::thread_rng();
let mut input = vec![];
let mut broken_pipe = false;
while input.len() < buf_compare.len() && !broken_pipe {
let span = (rng.next_u32() % 4096) as usize;
let mut next_bytes = vec![0u8; span];
let nr = match pipe_read.read(&mut next_bytes[..]) {
Ok(sz) => sz,
Err(e) => match e.kind() {
io::ErrorKind::BrokenPipe => {
test_debug!("Read pipe broke");
broken_pipe = true;
0
}
_ => {
assert!(false, "unwrapped err: {:?}", &e);
unreachable!();
}
},
};
input.extend_from_slice(&next_bytes[0..nr]);
test_debug!("Read buffer added {} bytes (now {})", nr, input.len());
assert!(
nr == span || input.len() == buf_compare.len(),
"nr = {}, span = {}, input.len() = {}, buf_compare.len() = {}",
nr,
span,
input.len(),
buf_compare.len()
);
}
test_debug!("consumer exit; read {} bytes", input.len());
if broken_pipe {
assert_eq!(input.len(), buf_compare.len());
}
assert_eq!(input, buf_compare.to_vec());
});
producer.join().unwrap();
consumer.join().unwrap();
}
#[test]
fn test_pipe_nonblocking_try_flush() {
let mut rng = rand::thread_rng();
let mut input = vec![];
for i in 0..100 {
let span = ((rng.next_u32() % 4096) + 1) as usize;
let mut next_bytes = vec![0u8; span];
rng.fill_bytes(&mut next_bytes);
input.push(next_bytes);
}
let (mut pipe_read, mut pipe_write) = Pipe::new();
pipe_read.set_nonblocking(true);
// test write/read over and over
for segment in input.iter() {
let mut bytes = vec![0u8; segment.len()];
// read should fail with EWOULDBLOCK
let res = pipe_read.read(&mut bytes).unwrap_err();
assert_eq!(res.kind(), io::ErrorKind::WouldBlock);
let _ = pipe_write.write(segment).unwrap();
// should should succeed since the data is in the receiver's inbox
let res = pipe_write.try_flush().unwrap();
assert!(res);
// read all data (should work now)
let nr = pipe_read.read(&mut bytes).unwrap();
assert_eq!(nr, segment.len());
assert_eq!(*segment, bytes);
// subsequent read fails with EWOULDBLOCK
let mut next_bytes = vec![0u8];
let res = pipe_read.read(&mut next_bytes).unwrap_err();
assert_eq!(res.kind(), io::ErrorKind::WouldBlock);
// flush should have succeeded
let res = pipe_write.try_flush().unwrap();
assert!(res);
}
// subsequent read fails with EWOULDBLOCK
let mut next_bytes = vec![0u8];
let res = pipe_read.read(&mut next_bytes).unwrap_err();
assert_eq!(res.kind(), io::ErrorKind::WouldBlock);
// once the write end is dropped, then this data is still consumable but we get broken-pipe
// once it's all been read.
let _ = pipe_write.write(&[1u8, 1u8]).unwrap();
drop(pipe_write);
let mut next_bytes = vec![0u8];
let res = pipe_read.read(&mut next_bytes).unwrap();
assert_eq!(res, 1);
let mut next_bytes = vec![0u8];
let res = pipe_read.read(&mut next_bytes).unwrap();
assert_eq!(res, 1);
let mut next_bytes = vec![0u8];
let res = pipe_read.read(&mut next_bytes).unwrap_err();
assert_eq!(res.kind(), io::ErrorKind::BrokenPipe);
}
#[test]
fn test_pipe_nonblocking_try_flush_multiple_write() {
let mut rng = rand::thread_rng();
let mut input = vec![];
for i in 0..100 {
let span = ((rng.next_u32() % 4096) + 1) as usize;
let mut next_bytes = vec![0u8; span];
rng.fill_bytes(&mut next_bytes);
input.push(next_bytes);
}
let (mut pipe_read, mut pipe_write) = Pipe::new();
pipe_read.set_nonblocking(true);
// test write/read over and over, but issue multiple writes.
// The first write should be flushed, but until a read happens,
// the subsequent writes should not flush.
for segment in input.iter() {
let mut bytes = vec![0u8; segment.len()];
// read should fail with EWOULDBLOCK
let res = pipe_read.read(&mut bytes).unwrap_err();
assert_eq!(res.kind(), io::ErrorKind::WouldBlock);
// write each _byte_
for (i, byte) in segment.iter().enumerate() {
let _ = pipe_write.write(&[*byte]).unwrap();
let res = pipe_write.try_flush().unwrap();
// first write flushes; subsequent ones don't
if i == 0 {
assert!(res);
} else {
assert!(!res);
}
}
// first read gets back 1 byte
let nr = pipe_read.read(&mut bytes).unwrap();
assert_eq!(nr, 1);
assert_eq!(bytes[0], segment[0]);
// try_flush puts all data into the reader's inbox,
// and drains the write buffer.
let res = pipe_write.try_flush().unwrap();
assert!(res);
// next read gets back the remaining data
let nr = pipe_read.read(&mut bytes[1..]).unwrap();
assert_eq!(nr, segment.len() - 1);
assert_eq!(*segment, bytes);
// subsequent read fails with EWOULDBLOCK
let mut next_bytes = vec![0u8];
let res = pipe_read.read(&mut next_bytes).unwrap_err();
assert_eq!(res.kind(), io::ErrorKind::WouldBlock);
// flush should have succeeded
let res = pipe_write.try_flush().unwrap();
assert!(res);
}
}
}