1 files changed, 82 insertions, 0 deletions
diff --git a/pkg/sentry/fs/host/socket_unsafe.go b/pkg/sentry/fs/host/socket_unsafe.go
new file mode 100644
index 000000000..bf8da6867
--- /dev/null
+++ b/pkg/sentry/fs/host/socket_unsafe.go
@@ -0,0 +1,82 @@
+// Copyright 2018 Google Inc.
+//
+// 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 host
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// buildIovec builds an iovec slice from the given []byte slice.
+func buildIovec(bufs [][]byte) (uintptr, []syscall.Iovec) {
+	var length uintptr
+	iovecs := make([]syscall.Iovec, 0, 10)
+	for i := range bufs {
+		if l := len(bufs[i]); l > 0 {
+			length += uintptr(l)
+			iovecs = append(iovecs, syscall.Iovec{
+				Base: &bufs[i][0],
+				Len:  uint64(l),
+			})
+		}
+	}
+	return length, iovecs
+}
+
+func fdReadVec(fd int, bufs [][]byte, control []byte, peek bool) (readLen uintptr, msgLen uintptr, controlLen uint64, err error) {
+	flags := uintptr(syscall.MSG_DONTWAIT | syscall.MSG_TRUNC)
+	if peek {
+		flags |= syscall.MSG_PEEK
+	}
+
+	length, iovecs := buildIovec(bufs)
+
+	var msg syscall.Msghdr
+	if len(control) != 0 {
+		msg.Control = &control[0]
+		msg.Controllen = uint64(len(control))
+	}
+
+	if len(iovecs) != 0 {
+		msg.Iov = &iovecs[0]
+		msg.Iovlen = uint64(len(iovecs))
+	}
+	n, _, e := syscall.RawSyscall(syscall.SYS_RECVMSG, uintptr(fd), uintptr(unsafe.Pointer(&msg)), flags)
+	if e != 0 {
+		return 0, 0, 0, e
+	}
+
+	if n > length {
+		return length, n, msg.Controllen, nil
+	}
+
+	return n, n, msg.Controllen, nil
+}
+
+func fdWriteVec(fd int, bufs [][]byte) (uintptr, error) {
+	_, iovecs := buildIovec(bufs)
+
+	var msg syscall.Msghdr
+	if len(iovecs) > 0 {
+		msg.Iov = &iovecs[0]
+		msg.Iovlen = uint64(len(iovecs))
+	}
+	n, _, e := syscall.RawSyscall(syscall.SYS_SENDMSG, uintptr(fd), uintptr(unsafe.Pointer(&msg)), syscall.MSG_DONTWAIT|syscall.MSG_NOSIGNAL)
+	if e != 0 {
+		return 0, e
+	}
+
+	return n, nil
+}