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
use alloc::boxed::Box;
use alloc::vec::Vec;
use core::usize;
use intrusive_collections::intrusive_adapter;
use intrusive_collections::{LinkedList, LinkedListLink};
use kalloc::list::List;
use kcore::{
chan::{ChanId, ChanKind, Dirent},
dev::Device,
error::{Error, Result},
};
use ksched::sync::Condvar;
use ksched::sync::Mutex;
fn parse_path<'a>(path: u64) -> (u64, usize, &'a mut Node) {
let raw_path = (path >> 3) << 3;
let node_id = (path - raw_path) as usize;
let node = unsafe { (raw_path as *mut Node).as_mut().unwrap() };
(raw_path, node_id, node)
}
#[derive(Default)]
pub struct Pipe(Mutex<LinkedList<NodeAdapter>>);
#[repr(align(8))]
struct Node {
nref: usize,
dref: [usize; 2],
cvar: [Condvar; 2],
data: [List<Vec<u8>>; 2],
link: LinkedListLink,
}
intrusive_adapter!(NodeAdapter = Box<Node>: Node { link: LinkedListLink });
#[async_trait::async_trait_try]
impl Device for Pipe {
async fn shutdown(self)
where
Self: Sized,
{
}
async fn attach(&self, aname: &[u8]) -> Result<ChanId>
where
Self: Sized,
{
let mut g = self.0.lock().await;
let node = Box::try_new(Node {
nref: 1,
dref: [0; 2],
cvar: [Condvar::new(), Condvar::new()],
data: [List::new(), List::new()],
link: LinkedListLink::new(),
})?;
let path = node.as_ref() as *const _ as u64;
debug_assert_eq!(path % 8, 0);
g.push_back(node);
Ok(ChanId {
path,
version: 0,
kind: ChanKind::Dir,
})
}
async fn open(
&self,
dir: &ChanId,
name: &[u8],
create_dir: Option<bool>,
) -> Result<Option<ChanId>> {
let g = self.0.lock().await;
let (raw_path, node_id, node) = parse_path(dir.path);
let ret = if name.is_empty() {
node.nref += 1;
if (1..=2).contains(&node_id) {
node.dref[node_id - 1] += 1;
}
Ok(Some(dir.clone()))
} else if create_dir.is_some() {
Err(Error::BadRequest("create in devpipe"))
} else {
debug_assert_eq!(dir.kind, ChanKind::Dir);
match name {
b"data" => {
node.nref += 1;
node.dref[0] += 1;
Ok(Some(ChanId {
path: raw_path + 1,
version: 0,
kind: ChanKind::File,
}))
}
b"data1" => {
node.nref += 1;
node.dref[1] += 1;
Ok(Some(ChanId {
path: raw_path + 2,
version: 0,
kind: ChanKind::File,
}))
}
_ => Ok(None),
}
};
drop(g);
ret
}
async fn close(&self, c: ChanId) {
let (_raw_path, node_id, node) = parse_path(c.path);
let mut g = self.0.lock().await;
node.nref -= 1;
if (1..=2).contains(&node_id) {
let di = node_id - 1;
node.dref[di] -= 1;
node.cvar[1 - di].notify_all();
}
if node.nref == 0 {
debug_assert_eq!(node.dref, [0, 0]);
let mut cur = unsafe { g.cursor_mut_from_ptr(node) };
cur.remove();
}
drop(g);
}
async fn remove(&self, c: &ChanId) -> Result<bool> {
Err(Error::BadRequest("remove file of devpipe"))
}
async fn truncate(&self, c: &ChanId, size: usize) -> Result<usize> {
Ok(0)
}
async fn stat(&self, c: &ChanId) -> Result<Dirent> {
todo!()
}
async fn wstat(&self, c: &ChanId, dirent: &Dirent) -> Result<()> {
todo!()
}
async fn read(&self, c: &ChanId, buf: &mut [u8], off: usize) -> Result<usize> {
debug_assert_eq!(c.kind, ChanKind::File);
let (_raw_path, node_id, node) = parse_path(c.path);
debug_assert!(node_id == 1 || node_id == 2);
let di = node_id - 1;
loop {
let g = self.0.lock().await;
let mut empty = false;
let mut i = 0;
if let Some(bytes) = node.data[di].back_mut() {
while i < buf.len() {
if let Some(b) = bytes.pop() {
buf[i] = b;
i += 1;
} else {
break;
}
}
if bytes.is_empty() {
empty = true;
}
}
if empty {
node.data[di].pop_back();
}
if empty || i != 0 || buf.len() == 0 {
return Ok(i);
}
if node.dref[1 - di] == 0 {
return Ok(0);
}
node.cvar[di].await_notify(g).await;
}
}
async fn write(&self, c: &ChanId, buf: &[u8], off: usize) -> Result<usize> {
debug_assert_eq!(c.kind, ChanKind::File);
let (_raw_path, node_id, node) = parse_path(c.path);
debug_assert!(node_id == 1 || node_id == 2);
let di = node_id - 1;
let mut v = Vec::new();
v.try_reserve(buf.len())?;
for b in buf {
v.push(*b);
}
v.reverse();
let g = self.0.lock().await;
if node.dref[1 - di] == 0 {
return Err(Error::Gone("write broken pipe"));
}
node.data[1 - di].push_front(v)?;
node.cvar[1 - di].notify_all();
drop(g);
Ok(buf.len())
}
}
#[cfg(test)]
mod tests {
use super::*;
use alloc::sync::Arc;
use kcore::chan::Chan;
use ksched::task;
#[test]
fn test_pipe() {
let devpipe = Arc::new(Pipe::default());
task::spawn(async move {
let p = Chan::attach(devpipe, b"").await.unwrap();
let data = p.open(b"data", None).await.unwrap().unwrap();
let data1 = p.open(b"data1", None).await.unwrap().unwrap();
assert_eq!(data.is_dir(), false);
assert_eq!(data1.is_dir(), false);
task::spawn(async move {
assert_eq!(data.write(b"12345", 0).await.unwrap(), 5);
let mut buf = [0u8; 10];
assert_eq!(data.read(&mut buf, 0).await.unwrap(), 4);
assert_eq!(&buf[0..4], b"abcd");
data.close().await;
})
.unwrap();
task::spawn(async move {
let mut buf = [0u8; 5];
assert_eq!(data1.read(&mut buf, 0).await.unwrap(), 5);
assert_eq!(&buf, b"12345");
assert_eq!(data1.write(b"abcd", 0).await.unwrap(), 4);
data1.close().await;
})
.unwrap();
p.close().await;
})
.unwrap();
task::run();
}
#[test]
fn test_pipe_read_portion() {
let devpipe = Arc::new(Pipe::default());
task::spawn(async move {
let p = Chan::attach(devpipe, b"").await.unwrap();
let data = p.open(b"data", None).await.unwrap().unwrap();
let data1 = p.open(b"data1", None).await.unwrap().unwrap();
task::spawn(async move {
assert_eq!(data.write(b"12345abcd", 0).await.unwrap(), 9);
assert_eq!(data.write(b"0", 0).await.unwrap(), 1);
data.close().await;
})
.unwrap();
task::spawn(async move {
let mut buf = [0u8; 5];
assert_eq!(data1.read(&mut buf, 0).await.unwrap(), 5);
assert_eq!(&buf, b"12345");
assert_eq!(data1.read(&mut buf, 0).await.unwrap(), 4);
assert_eq!(&buf[0..4], b"abcd");
assert_eq!(data1.read(&mut buf, 0).await.unwrap(), 1);
assert_eq!(&buf[0..1], b"0");
assert_eq!(data1.read(&mut buf, 0).await.unwrap(), 0);
data1.close().await;
})
.unwrap();
p.close().await;
})
.unwrap();
task::run();
}
#[test]
fn test_pipe_write_broken() {
let devpipe = Arc::new(Pipe::default());
task::spawn(async move {
let p = Chan::attach(devpipe, b"").await.unwrap();
let data = p.open(b"data", None).await.unwrap().unwrap();
assert_eq!(data.write(b"", 0).await.is_err(), true);
data.close().await;
p.close().await;
})
.unwrap();
task::run();
}
#[test]
fn test_pipe_read_empty() {
let devpipe = Arc::new(Pipe::default());
task::spawn(async move {
let p = Chan::attach(devpipe, b"").await.unwrap();
let data = p.open(b"data", None).await.unwrap().unwrap();
let mut buf = [0; 10];
assert_eq!(data.read(&mut buf, 0).await.unwrap(), 0);
data.close().await;
p.close().await;
})
.unwrap();
task::run();
}
}