Add vfs.FileDescription to FD table

FD table now holds both VFS1 and VFS2 types and uses the correct
one based on what's set.

Parts of this CL are just initial changes (e.g. sys_read.go,
runsc/main.go) to serve as a template for the remaining changes.

Updates #1487
Updates #1623

PiperOrigin-RevId: 292023223

1 files changed, 1 insertions, 1 deletions

diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go
index c54735148..421845ebb 100644
--- a/pkg/sentry/syscalls/linux/sys_file.go
+++ b/pkg/sentry/syscalls/linux/sys_file.go
@@ -767,7 +767,7 @@ func Close(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
 	// Note that Remove provides a reference on the file that we may use to
 	// flush. It is still active until we drop the final reference below
 	// (and other reference-holding operations complete).
-	file := t.FDTable().Remove(fd)
+	file, _ := t.FDTable().Remove(fd)
 	if file == nil {
 		return 0, nil, syserror.EBADF
 	}