Add shimdiag flag to find shim process ID for shims

* Adds a new -pids flag to the `shimdiag list` command that will print out the
process ID of the shim executable.

Sample output:

PS C:\> shimdiag.exe list -pids
Shim                                                                     Pid
k8s.io-3719754aab39925924b0beb27d2a195a4a6784c6ebe3690b81b2e7274a7021af  65892
k8s.io-908ea3697874891fd5814b1967515d3214257b65fc1974bdafd17276ee8ba3e5  69444

Signed-off-by: Daniel Canter <[email protected]>

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

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"os"
 	"runtime"
 	"strings"
 	"sync"
@@ -474,3 +475,18 @@ func (s *service) DiagStacks(ctx context.Context, req *shimdiag.StacksRequest) (
 	}
 	return resp, nil
 }
+
+func (s *service) DiagPid(ctx context.Context, req *shimdiag.PidRequest) (*shimdiag.PidResponse, error) {
+	if s == nil {
+		return nil, nil
+	}
+	defer panicRecover()
+	ctx, span := trace.StartSpan(ctx, "DiagPid")
+	defer span.End()
+
+	span.AddAttributes(trace.StringAttribute("tid", s.tid))
+
+	return &shimdiag.PidResponse{
+		Pid: int32(os.Getpid()),
+	}, nil
+}

cmd/shimdiag/list.go

@@ -1,25 +1,69 @@
 package main
 
 import (
+	"context"
 	"fmt"
+	"os"
+	"text/tabwriter"
 
 	"github.com/Microsoft/hcsshim/internal/appargs"
+	"github.com/Microsoft/hcsshim/internal/shimdiag"
 	"github.com/urfave/cli"
 )
 
 var listCommand = cli.Command{
 	Name:      "list",
 	Usage:     "Lists running shims",
 	ArgsUsage: " ",
-	Before:    appargs.Validate(),
+	Flags: []cli.Flag{
+		cli.BoolFlag{
+			Name:  "pids",
+			Usage: "Shows the process IDs of each shim",
+		},
+	},
+	Before: appargs.Validate(),
 	Action: func(ctx *cli.Context) error {
+		pids := ctx.Bool("pids")
 		shims, err := findShims("")
 		if err != nil {
 			return err
 		}
+
+		getPid := func(shimStr string) (int32, error) {
+			shim, err := getShim(shimStr)
+			if err != nil {
+				return 0, err
+			}
+			defer shim.Close()
+
+			svc := shimdiag.NewShimDiagClient(shim)
+			resp, err := svc.DiagPid(context.Background(), &shimdiag.PidRequest{})
+			if err != nil {
+				return 0, err
+			}
+			return resp.Pid, nil
+		}
+
+		w := new(tabwriter.Writer)
+		w.Init(os.Stdout, 0, 8, 0, '\t', 0)
+
+		if pids {
+			fmt.Fprintln(w, "Shim \t Pid")
+		}
+
 		for _, shim := range shims {
-			fmt.Println(shim)
+			output := shim
+			if pids {
+				pid, err := getPid(shim)
+				if err != nil {
+					return err
+				}
+				fmt.Fprintf(w, "%s \t %d\n", output, pid)
+			} else {
+				fmt.Println(shim)
+			}
 		}
+		w.Flush()
 		return nil
 	},
 }