virtcontainers: copy files from host to guest

Some hypervisors like firecracker don't support 9p, hence "static" files should
be copied from host to container rootfs (guest). File are copied using CopyFile
request.

Signed-off-by: Julio Montes <[email protected]>

virtcontainers/kata_agent.go

@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -252,6 +253,11 @@ func (k *kataAgent) configure(h hypervisor, id, sharePath string, builtin bool,
 		k.proxyBuiltIn = true
 	}
 
+	caps := h.capabilities()
+	if !caps.is9pSupported() {
+		return nil
+	}
+
 	// Adding the shared volume.
 	// This volume contains all bind mounted container bundles.
 	sharedVolume := Volume{
@@ -612,22 +618,27 @@ func (k *kataAgent) startSandbox(sandbox *Sandbox) error {
 		return err
 	}
 
-	sharedDir9pOptions = append(sharedDir9pOptions, fmt.Sprintf("msize=%d", sandbox.config.HypervisorConfig.Msize9p))
+	storages := []*grpc.Storage{}
+	caps := sandbox.hypervisor.capabilities()
 
-	// We mount the shared directory in a predefined location
-	// in the guest.
-	// This is where at least some of the host config files
-	// (resolv.conf, etc...) and potentially all container
-	// rootfs will reside.
-	sharedVolume := &grpc.Storage{
-		Driver:     kata9pDevType,
-		Source:     mountGuest9pTag,
-		MountPoint: kataGuestSharedDir,
-		Fstype:     type9pFs,
-		Options:    sharedDir9pOptions,
-	}
+	if caps.is9pSupported() {
+		sharedDir9pOptions = append(sharedDir9pOptions, fmt.Sprintf("msize=%d", sandbox.config.HypervisorConfig.Msize9p))
 
-	storages := []*grpc.Storage{sharedVolume}
+		// We mount the shared directory in a predefined location
+		// in the guest.
+		// This is where at least some of the host config files
+		// (resolv.conf, etc...) and potentially all container
+		// rootfs will reside.
+		sharedVolume := &grpc.Storage{
+			Driver:     kata9pDevType,
+			Source:     mountGuest9pTag,
+			MountPoint: kataGuestSharedDir,
+			Fstype:     type9pFs,
+			Options:    sharedDir9pOptions,
+		}
+
+		storages = append(storages, sharedVolume)
+	}
 
 	if sandbox.shmSize > 0 {
 		path := filepath.Join(kataGuestSandboxDir, shmDir)
@@ -915,6 +926,48 @@ func (k *kataAgent) buildContainerRootfs(sandbox *Sandbox, c *Container, rootPat
 	return nil, nil
 }
 
+func (k *kataAgent) copyFiles(containerMounts, newMounts []Mount) error {
+	for _, nm := range newMounts {
+		for _, m := range containerMounts {
+			if nm.Destination != m.Destination {
+				continue
+			}
+
+			st, err := os.Stat(m.HostPath)
+			if err != nil {
+				k.Logger().WithError(err).WithField("path", m.HostPath).Error("Could get file information")
+				continue
+			}
+
+			b, err := ioutil.ReadFile(m.HostPath)
+			if err != nil {
+				k.Logger().WithError(err).WithField("path", m.HostPath).Error("Could not read file")
+				continue
+			}
+
+			k.Logger().WithFields(logrus.Fields{
+				"source": m.HostPath,
+				"dest":   nm.Source,
+			}).Debugf("Copying file from host to guest")
+
+			cpReq := &grpc.CopyFileRequest{
+				Content:  b,
+				Path:     nm.Source,
+				Offset:   0,
+				DirMode:  uint32(dirMode),
+				FileMode: uint32(st.Mode().Perm()),
+				FileSize: st.Size(),
+			}
+
+			if _, err = k.sendReq(cpReq); err != nil {
+				k.Logger().WithError(err).Error("Could not send CopyFile request")
+			}
+		}
+	}
+
+	return nil
+}
+
 func (k *kataAgent) createContainer(sandbox *Sandbox, c *Container) (p *Process, err error) {
 	span, _ := k.trace("createContainer")
 	defer span.Finish()
@@ -1003,6 +1056,14 @@ func (k *kataAgent) createContainer(sandbox *Sandbox, c *Container) (p *Process,
 
 	k.handleShm(grpcSpec, sandbox)
 
+	caps := sandbox.hypervisor.capabilities()
+	if !caps.is9pSupported() {
+		// 9p is not supported, files must be copied
+		if err := k.copyFiles(c.mounts, newMounts); err != nil {
+			return nil, err
+		}
+	}
+
 	req := &grpc.CreateContainerRequest{
 		ContainerId:  c.id,
 		ExecId:       c.id,
@@ -1490,6 +1551,9 @@ func (k *kataAgent) installReqFunc(c *kataclient.AgentClient) {
 	k.reqHandlers["grpc.GuestDetailsRequest"] = func(ctx context.Context, req interface{}, opts ...golangGrpc.CallOption) (interface{}, error) {
 		return k.client.GetGuestDetails(ctx, req.(*grpc.GuestDetailsRequest), opts...)
 	}
+	k.reqHandlers["grpc.CopyFileRequest"] = func(ctx context.Context, req interface{}, opts ...golangGrpc.CallOption) (interface{}, error) {
+		return k.client.CopyFile(ctx, req.(*grpc.CopyFileRequest), opts...)
+	}
 	k.reqHandlers["grpc.SetGuestDateTimeRequest"] = func(ctx context.Context, req interface{}, opts ...golangGrpc.CallOption) (interface{}, error) {
 		return k.client.SetGuestDateTime(ctx, req.(*grpc.SetGuestDateTimeRequest), opts...)
 	}