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, 25 insertions, 0 deletions

diff --git a/pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go b/pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go
new file mode 100644
index 000000000..6af5c400f
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go
@@ -0,0 +1,25 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package vfs2
+
+import (
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/syscalls"
+)
+
+// Override syscall table to add syscalls implementations from this package.
+func Override(table map[uintptr]kernel.Syscall) {
+	table[63] = syscalls.Supported("read", Read)
+}