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, 5 insertions, 106 deletions

diff --git a/pkg/sentry/kernel/pipe/reader_writer.go b/pkg/sentry/kernel/pipe/reader_writer.go
index 7c307f013..b4d29fc77 100644
--- a/pkg/sentry/kernel/pipe/reader_writer.go
+++ b/pkg/sentry/kernel/pipe/reader_writer.go
@@ -16,16 +16,12 @@ package pipe
 
 import (
 	"io"
-	"math"
-	"syscall"
 
-	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
-	"gvisor.dev/gvisor/pkg/waiter"
 )
 
 // ReaderWriter satisfies the FileOperations interface and services both
@@ -45,124 +41,27 @@ type ReaderWriter struct {
 	*Pipe
 }
 
-// Release implements fs.FileOperations.Release.
-func (rw *ReaderWriter) Release() {
-	rw.Pipe.rClose()
-	rw.Pipe.wClose()
-
-	// Wake up readers and writers.
-	rw.Pipe.Notify(waiter.EventIn | waiter.EventOut)
-}
-
 // Read implements fs.FileOperations.Read.
 func (rw *ReaderWriter) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, _ int64) (int64, error) {
-	n, err := rw.Pipe.read(ctx, readOps{
-		left: func() int64 {
-			return dst.NumBytes()
-		},
-		limit: func(l int64) {
-			dst = dst.TakeFirst64(l)
-		},
-		read: func(buf *buffer) (int64, error) {
-			n, err := dst.CopyOutFrom(ctx, buf)
-			dst = dst.DropFirst64(n)
-			return n, err
-		},
-	})
-	if n > 0 {
-		rw.Pipe.Notify(waiter.EventOut)
-	}
-	return n, err
+	return rw.Pipe.Read(ctx, dst)
 }
 
 // WriteTo implements fs.FileOperations.WriteTo.
 func (rw *ReaderWriter) WriteTo(ctx context.Context, _ *fs.File, w io.Writer, count int64, dup bool) (int64, error) {
-	ops := readOps{
-		left: func() int64 {
-			return count
-		},
-		limit: func(l int64) {
-			count = l
-		},
-		read: func(buf *buffer) (int64, error) {
-			n, err := buf.ReadToWriter(w, count, dup)
-			count -= n
-			return n, err
-		},
-	}
-	if dup {
-		// There is no notification for dup operations.
-		return rw.Pipe.dup(ctx, ops)
-	}
-	n, err := rw.Pipe.read(ctx, ops)
-	if n > 0 {
-		rw.Pipe.Notify(waiter.EventOut)
-	}
-	return n, err
+	return rw.Pipe.WriteTo(ctx, w, count, dup)
 }
 
 // Write implements fs.FileOperations.Write.
 func (rw *ReaderWriter) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, _ int64) (int64, error) {
-	n, err := rw.Pipe.write(ctx, writeOps{
-		left: func() int64 {
-			return src.NumBytes()
-		},
-		limit: func(l int64) {
-			src = src.TakeFirst64(l)
-		},
-		write: func(buf *buffer) (int64, error) {
-			n, err := src.CopyInTo(ctx, buf)
-			src = src.DropFirst64(n)
-			return n, err
-		},
-	})
-	if n > 0 {
-		rw.Pipe.Notify(waiter.EventIn)
-	}
-	return n, err
+	return rw.Pipe.Write(ctx, src)
 }
 
 // ReadFrom implements fs.FileOperations.WriteTo.
 func (rw *ReaderWriter) ReadFrom(ctx context.Context, _ *fs.File, r io.Reader, count int64) (int64, error) {
-	n, err := rw.Pipe.write(ctx, writeOps{
-		left: func() int64 {
-			return count
-		},
-		limit: func(l int64) {
-			count = l
-		},
-		write: func(buf *buffer) (int64, error) {
-			n, err := buf.WriteFromReader(r, count)
-			count -= n
-			return n, err
-		},
-	})
-	if n > 0 {
-		rw.Pipe.Notify(waiter.EventIn)
-	}
-	return n, err
-}
-
-// Readiness returns the ready events in the underlying pipe.
-func (rw *ReaderWriter) Readiness(mask waiter.EventMask) waiter.EventMask {
-	return rw.Pipe.rwReadiness() & mask
+	return rw.Pipe.ReadFrom(ctx, r, count)
 }
 
 // Ioctl implements fs.FileOperations.Ioctl.
 func (rw *ReaderWriter) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO, args arch.SyscallArguments) (uintptr, error) {
-	// Switch on ioctl request.
-	switch int(args[1].Int()) {
-	case linux.FIONREAD:
-		v := rw.queued()
-		if v > math.MaxInt32 {
-			v = math.MaxInt32 // Silently truncate.
-		}
-		// Copy result to user-space.
-		_, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{
-			AddressSpaceActive: true,
-		})
-		return 0, err
-	default:
-		return 0, syscall.ENOTTY
-	}
+	return rw.Pipe.Ioctl(ctx, io, args)
 }