Support pipes and sockets in VFS2 gofer fs.

Named pipes and sockets can be represented in two ways in gofer fs:
1. As a file on the remote filesystem. In this case, all file operations are
   passed through 9p.
2. As a synthetic file that is internal to the sandbox. In this case, the
   dentry stores an endpoint or VFSPipe for sockets and pipes respectively,
   which replaces interactions with the remote fs through the gofer.
In gofer.filesystem.MknodAt, we attempt to call mknod(2) through 9p,
and if it fails, fall back to the synthetic version.

Updates #1200.

PiperOrigin-RevId: 308828161

1 files changed, 27 insertions, 27 deletions

diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index 9015f2cc1..8d7f8f8af 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -351,33 +351,6 @@ func (vfs *VirtualFilesystem) MknodAt(ctx context.Context, creds *auth.Credentia
 	}
 }
 
-// BoundEndpointAt gets the bound endpoint at the given path, if one exists.
-func (vfs *VirtualFilesystem) BoundEndpointAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) (transport.BoundEndpoint, error) {
-	if !pop.Path.Begin.Ok() {
-		if pop.Path.Absolute {
-			return nil, syserror.ECONNREFUSED
-		}
-		return nil, syserror.ENOENT
-	}
-	rp := vfs.getResolvingPath(creds, pop)
-	for {
-		bep, err := rp.mount.fs.impl.BoundEndpointAt(ctx, rp)
-		if err == nil {
-			vfs.putResolvingPath(rp)
-			return bep, nil
-		}
-		if checkInvariants {
-			if rp.canHandleError(err) && rp.Done() {
-				panic(fmt.Sprintf("%T.BoundEndpointAt() consumed all path components and returned %v", rp.mount.fs.impl, err))
-			}
-		}
-		if !rp.handleError(err) {
-			vfs.putResolvingPath(rp)
-			return nil, err
-		}
-	}
-}
-
 // OpenAt returns a FileDescription providing access to the file at the given
 // path. A reference is taken on the returned FileDescription.
 func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *OpenOptions) (*FileDescription, error) {
@@ -675,6 +648,33 @@ func (vfs *VirtualFilesystem) UnlinkAt(ctx context.Context, creds *auth.Credenti
 	}
 }
 
+// BoundEndpointAt gets the bound endpoint at the given path, if one exists.
+func (vfs *VirtualFilesystem) BoundEndpointAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *BoundEndpointOptions) (transport.BoundEndpoint, error) {
+	if !pop.Path.Begin.Ok() {
+		if pop.Path.Absolute {
+			return nil, syserror.ECONNREFUSED
+		}
+		return nil, syserror.ENOENT
+	}
+	rp := vfs.getResolvingPath(creds, pop)
+	for {
+		bep, err := rp.mount.fs.impl.BoundEndpointAt(ctx, rp, *opts)
+		if err == nil {
+			vfs.putResolvingPath(rp)
+			return bep, nil
+		}
+		if checkInvariants {
+			if rp.canHandleError(err) && rp.Done() {
+				panic(fmt.Sprintf("%T.BoundEndpointAt() consumed all path components and returned %v", rp.mount.fs.impl, err))
+			}
+		}
+		if !rp.handleError(err) {
+			vfs.putResolvingPath(rp)
+			return nil, err
+		}
+	}
+}
+
 // ListxattrAt returns all extended attribute names for the file at the given
 // path.
 func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, size uint64) ([]string, error) {