Add utility function for sharing files into UVMs from the host

cmd/containerd-shim-runhcs-v1/task_wcow_podsandbox.go

@@ -8,10 +8,7 @@ import (
 	"github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/options"
 	"github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/stats"
 	"github.com/Microsoft/hcsshim/internal/cmd"
-	"github.com/Microsoft/hcsshim/internal/guestrequest"
 	"github.com/Microsoft/hcsshim/internal/log"
-	"github.com/Microsoft/hcsshim/internal/requesttype"
-	hcsschema "github.com/Microsoft/hcsshim/internal/schema2"
 	"github.com/Microsoft/hcsshim/internal/shimdiag"
 	"github.com/Microsoft/hcsshim/internal/uvm"
 	eventstypes "github.com/containerd/containerd/api/events"
@@ -243,25 +240,7 @@ func (wpst *wcowPodSandboxTask) Share(ctx context.Context, req *shimdiag.ShareRe
 	if wpst.host == nil {
 		return errTaskNotIsolated
 	}
-	options := wpst.host.DefaultVSMBOptions(req.ReadOnly)
-	_, err := wpst.host.AddVSMB(ctx, req.HostPath, options)
-	if err != nil {
-		return err
-	}
-	sharePath, err := wpst.host.GetVSMBUvmPath(ctx, req.HostPath, req.ReadOnly)
-	if err != nil {
-		return err
-	}
-	guestReq := guestrequest.GuestRequest{
-		ResourceType: guestrequest.ResourceTypeMappedDirectory,
-		RequestType:  requesttype.Add,
-		Settings: &hcsschema.MappedDirectory{
-			HostPath:      sharePath,
-			ContainerPath: req.UvmPath,
-			ReadOnly:      req.ReadOnly,
-		},
-	}
-	return wpst.host.GuestRequest(ctx, guestReq)
+	return wpst.host.Share(ctx, req.HostPath, req.UvmPath, req.ReadOnly)
 }
 
 func (wpst *wcowPodSandboxTask) Stats(ctx context.Context) (*stats.Statistics, error) {

internal/uvm/share.go

@@ -0,0 +1,72 @@
+package uvm
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/Microsoft/hcsshim/internal/guestrequest"
+	"github.com/Microsoft/hcsshim/internal/requesttype"
+	hcsschema "github.com/Microsoft/hcsshim/internal/schema2"
+)
+
+// Share shares in file(s) from `reqHostPath` on the host machine to `reqUVMPath` inside the UVM.
+// This function handles both LCOW and WCOW scenarios.
+func (uvm *UtilityVM) Share(ctx context.Context, reqHostPath, reqUVMPath string, readOnly bool) (err error) {
+	if uvm.OS() == "windows" {
+		options := uvm.DefaultVSMBOptions(readOnly)
+		vsmbShare, err := uvm.AddVSMB(ctx, reqHostPath, options)
+		if err != nil {
+			return err
+		}
+		defer func() {
+			if err != nil {
+				vsmbShare.Release(ctx)
+			}
+		}()
+
+		sharePath, err := uvm.GetVSMBUvmPath(ctx, reqHostPath, readOnly)
+		if err != nil {
+			return err
+		}
+		guestReq := guestrequest.GuestRequest{
+			ResourceType: guestrequest.ResourceTypeMappedDirectory,
+			RequestType:  requesttype.Add,
+			Settings: &hcsschema.MappedDirectory{
+				HostPath:      sharePath,
+				ContainerPath: reqUVMPath,
+				ReadOnly:      readOnly,
+			},
+		}
+		if err := uvm.GuestRequest(ctx, guestReq); err != nil {
+			return err
+		}
+	} else {
+		st, err := os.Stat(reqHostPath)
+		if err != nil {
+			return fmt.Errorf("could not open '%s' path on host: %s", reqHostPath, err)
+		}
+		var (
+			hostPath       string = reqHostPath
+			restrictAccess bool
+			fileName       string
+			allowedNames   []string
+		)
+		if !st.IsDir() {
+			hostPath, fileName = filepath.Split(hostPath)
+			allowedNames = append(allowedNames, fileName)
+			restrictAccess = true
+		}
+		plan9Share, err := uvm.AddPlan9(ctx, hostPath, reqUVMPath, readOnly, restrictAccess, allowedNames)
+		if err != nil {
+			return err
+		}
+		defer func() {
+			if err != nil {
+				plan9Share.Release(ctx)
+			}
+		}()
+	}
+	return nil
+}