Refactor pipe to support VFS2.

* Pulls common functionality (IO and locking on open) into pipe_util.go.
* Adds pipe/vfs.go, which implements a subset of vfs.FileDescriptionImpl.

A subsequent change will add support for pipes in memfs.

PiperOrigin-RevId: 275322385

1 files changed, 20 insertions, 4 deletions

diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go
index 8e4e8e82e..1a1b38f83 100644
--- a/pkg/sentry/kernel/pipe/pipe.go
+++ b/pkg/sentry/kernel/pipe/pipe.go
@@ -111,11 +111,27 @@ func NewPipe(isNamed bool, sizeBytes, atomicIOBytes int64) *Pipe {
 	if atomicIOBytes > sizeBytes {
 		atomicIOBytes = sizeBytes
 	}
-	return &Pipe{
-		isNamed:       isNamed,
-		max:           sizeBytes,
-		atomicIOBytes: atomicIOBytes,
+	var p Pipe
+	initPipe(&p, isNamed, sizeBytes, atomicIOBytes)
+	return &p
+}
+
+func initPipe(pipe *Pipe, isNamed bool, sizeBytes, atomicIOBytes int64) {
+	if sizeBytes < MinimumPipeSize {
+		sizeBytes = MinimumPipeSize
+	}
+	if sizeBytes > MaximumPipeSize {
+		sizeBytes = MaximumPipeSize
+	}
+	if atomicIOBytes <= 0 {
+		atomicIOBytes = 1
+	}
+	if atomicIOBytes > sizeBytes {
+		atomicIOBytes = sizeBytes
 	}
+	pipe.isNamed = isNamed
+	pipe.max = sizeBytes
+	pipe.atomicIOBytes = atomicIOBytes
 }
 
 // NewConnectedPipe initializes a pipe and returns a pair of objects