Enable runsc/fsgofer support on arm64.

newfstatat() syscall is not supported on arm64, so we resort
to use the fstatat() syscall.

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: I9e89d46c5ec9ae07db201c9da5b6dda9bfd2eaf0

1 files changed, 49 insertions, 0 deletions

diff --git a/runsc/fsgofer/fsgofer_amd64_unsafe.go b/runsc/fsgofer/fsgofer_amd64_unsafe.go
new file mode 100644
index 000000000..5d4aab597
--- /dev/null
+++ b/runsc/fsgofer/fsgofer_amd64_unsafe.go
@@ -0,0 +1,49 @@
+// Copyright 2019 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.
+
+// +build amd64
+
+package fsgofer
+
+import (
+	"syscall"
+	"unsafe"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/syserr"
+)
+
+func statAt(dirFd int, name string) (syscall.Stat_t, error) {
+	nameBytes, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		return syscall.Stat_t{}, err
+	}
+	namePtr := unsafe.Pointer(nameBytes)
+
+	var stat syscall.Stat_t
+	statPtr := unsafe.Pointer(&stat)
+
+	if _, _, errno := syscall.Syscall6(
+		syscall.SYS_NEWFSTATAT,
+		uintptr(dirFd),
+		uintptr(namePtr),
+		uintptr(statPtr),
+		linux.AT_SYMLINK_NOFOLLOW,
+		0,
+		0); errno != 0 {
+
+		return syscall.Stat_t{}, syserr.FromHost(errno).ToError()
+	}
+	return stat, nil
+}