Add new function to exec cmds in host for process isolated containers

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

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"time"
 
 	"github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/options"
@@ -11,6 +12,8 @@ import (
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 )
 
+var errTaskNotIsolated = errors.New("task is not isolated")
+
 // shimTaskPidPair groups a process pid to its execID if it was user generated.
 type shimTaskPidPair struct {
 	// Pid is the pid of the container process.

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

@@ -594,7 +594,7 @@ func (ht *hcsTask) closeHost(ctx context.Context) {
 
 func (ht *hcsTask) ExecInHost(ctx context.Context, req *shimdiag.ExecProcessRequest) (int, error) {
 	if ht.host == nil {
-		return 0, errors.New("task is not isolated")
+		return cmd.ExecInShimHost(ctx, req)
 	}
 	return cmd.ExecInUvm(ctx, ht.host, req)
 }
@@ -613,7 +613,7 @@ func (ht *hcsTask) DumpGuestStacks(ctx context.Context) string {
 
 func (ht *hcsTask) Share(ctx context.Context, req *shimdiag.ShareRequest) error {
 	if ht.host == nil {
-		return errors.New("task is not isolated")
+		return errTaskNotIsolated
 	}
 	// For hyper-v isolated WCOW the task used isn't the standard hcsTask so we
 	// only have to deal with the LCOW case here.

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

@@ -222,7 +222,7 @@ func (wpst *wcowPodSandboxTask) waitParentExit() {
 
 func (wpst *wcowPodSandboxTask) ExecInHost(ctx context.Context, req *shimdiag.ExecProcessRequest) (int, error) {
 	if wpst.host == nil {
-		return 0, errors.New("task is not isolated")
+		return 0, errTaskNotIsolated
 	}
 	return cmd.ExecInUvm(ctx, wpst.host, req)
 }
@@ -241,7 +241,7 @@ func (wpst *wcowPodSandboxTask) DumpGuestStacks(ctx context.Context) string {
 
 func (wpst *wcowPodSandboxTask) Share(ctx context.Context, req *shimdiag.ShareRequest) error {
 	if wpst.host == nil {
-		return errors.New("task is not isolated")
+		return errTaskNotIsolated
 	}
 	options := wpst.host.DefaultVSMBOptions(req.ReadOnly)
 	_, err := wpst.host.AddVSMB(ctx, req.HostPath, options)

internal/cmd/diag.go

@@ -3,13 +3,16 @@ package cmd
 import (
 	"context"
 	"errors"
+	"os/exec"
 
 	"github.com/Microsoft/hcsshim/internal/log"
 	"github.com/Microsoft/hcsshim/internal/logfields"
 	"github.com/Microsoft/hcsshim/internal/shimdiag"
 	"github.com/Microsoft/hcsshim/internal/uvm"
+	errorspkg "github.com/pkg/errors"
 )
 
+// ExecInUvm is a helper function used to execute commands specified in `req` inside the given UVM.
 func ExecInUvm(ctx context.Context, vm *uvm.UtilityVM, req *shimdiag.ExecProcessRequest) (int, error) {
 	if len(req.Args) == 0 {
 		return 0, errors.New("missing command")
@@ -34,3 +37,24 @@ func ExecInUvm(ctx context.Context, vm *uvm.UtilityVM, req *shimdiag.ExecProcess
 	err = cmd.Run()
 	return cmd.ExitState.ExitCode(), err
 }
+
+// ExecInShimHost is a helper function used to execute commands specified in `req` in the shim's
+// hosting system.
+func ExecInShimHost(ctx context.Context, req *shimdiag.ExecProcessRequest) (int, error) {
+	if len(req.Args) == 0 {
+		return 0, errors.New("missing command")
+	}
+	cmdArgsWithoutName := []string{""}
+	if len(req.Args) > 1 {
+		cmdArgsWithoutName = req.Args[1:]
+	}
+	cmd := exec.Command(req.Args[0], cmdArgsWithoutName...)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			return exiterr.ExitCode(), errorspkg.Wrapf(exiterr, "command output: %v", string(output))
+		}
+		return -1, errorspkg.Wrapf(err, "command output: %v", string(output))
+	}
+	return 0, nil
+}