Fix relative paths (with dot) not working for job containers

internal/jobcontainers/jobcontainer.go

@@ -174,14 +174,22 @@ func (c *JobContainer) CreateProcess(ctx context.Context, config interface{}) (_
 		return nil, errors.New("console emulation not supported for job containers")
 	}
 
-	absPath, commandLine, err := getApplicationName(conf.CommandLine, c.sandboxMount, os.Getenv("PATH"))
+	// Replace any occurences of the sandbox mount point env variable in the commandline.
+	// %CONTAINER_SANDBOX_MOUNTPOINT%\mybinary.exe -> C:\C\123456789\mybinary.exe
+	commandLine := c.replaceWithMountPoint(conf.CommandLine)
+
+	workDir := c.sandboxMount
+	if conf.WorkingDirectory != "" {
+		workDir = c.replaceWithMountPoint(conf.WorkingDirectory)
+	}
+
+	// Reassign commandline here in case it needed to be quoted. For example if "foo bar baz" was supplied, and
+	// "foo bar.exe" exists, then return: "\"foo bar\" baz"
+	absPath, commandLine, err := getApplicationName(commandLine, workDir, os.Getenv("PATH"))
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to get application name from commandline %q", conf.CommandLine)
 	}
 
-	commandLine = strings.ReplaceAll(commandLine, "%"+sandboxMountPointEnvVar+"%", c.sandboxMount)
-	commandLine = strings.ReplaceAll(commandLine, "$env:"+sandboxMountPointEnvVar, c.sandboxMount)
-
 	var token windows.Token
 	if getUserTokenInheritAnnotation(c.spec.Annotations) {
 		token, err = openCurrentProcessToken()
@@ -205,12 +213,12 @@ func (c *JobContainer) CreateProcess(ctx context.Context, config interface{}) (_
 
 	cmd := &exec.Cmd{
 		Env:  env,
-		Dir:  c.sandboxMount,
+		Dir:  workDir,
 		Path: absPath,
 		Args: splitArgs(commandLine),
 		SysProcAttr: &syscall.SysProcAttr{
 			// CREATE_BREAKAWAY_FROM_JOB to make sure that we're not inheriting the job object (and by extension its limits)
-			// from whatever process is running this code.
+			// from whatever process is going to launch the container.
 			CreationFlags: windows.CREATE_NEW_PROCESS_GROUP | windows.CREATE_BREAKAWAY_FROM_JOB,
 			Token:         syscall.Token(token),
 		},
@@ -566,3 +574,9 @@ func systemProcessInformation() ([]*winapi.SYSTEM_PROCESS_INFORMATION, error) {
 
 	return procInfos, nil
 }
+
+// Takes a string and replaces any occurences of CONTAINER_SANDBOX_MOUNT_POINT with where the containers volume is mounted.
+func (c *JobContainer) replaceWithMountPoint(str string) string {
+	str = strings.ReplaceAll(str, "%"+sandboxMountPointEnvVar+"%", c.sandboxMount)
+	return strings.ReplaceAll(str, "$env:"+sandboxMountPointEnvVar, c.sandboxMount)
+}

internal/jobcontainers/path.go

@@ -3,6 +3,7 @@ package jobcontainers
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/Microsoft/hcsshim/internal/winapi"
@@ -71,6 +72,10 @@ func getApplicationName(commandLine, workingDirectory, pathEnv string) (string,
 		searchPath string
 		result     string
 	)
+
+	// Clean the path, to get rid of any . elements
+	commandLine = filepath.Clean(commandLine)
+
 	// First we get the system paths concatenated with semicolons (C:\windows;C:\windows\system32;C:\windows\system;)
 	// and use this as the basis for the directories to search for the application.
 	systemPaths, err := getSystemPaths()

internal/jobcontainers/path_test.go

@@ -3,9 +3,16 @@ package jobcontainers
 import (
 	"os"
 	"os/exec"
+	"strings"
 	"testing"
 )
 
+func assertStr(t *testing.T, a string, b string) {
+	if !strings.EqualFold(a, b) {
+		t.Fatalf("expected %s, got %s", a, b)
+	}
+}
+
 func TestSearchPath(t *testing.T) {
 	// Testing that relative paths work.
 	_, err := searchPathForExe("windows\\system32\\ping", "C:\\")
@@ -17,30 +24,52 @@ func TestSearchPath(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+
+	_, err = searchPathForExe("ping", "C:\\windows\\system32")
+	if err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestGetApplicationName(t *testing.T) {
+	expected := "C:\\WINDOWS\\system32\\ping.exe"
+
 	cwd, err := os.Getwd()
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	_, _, err = getApplicationName("ping", cwd, os.Getenv("PATH"))
+	path, _, err := getApplicationName("ping", cwd, os.Getenv("PATH"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	assertStr(t, expected, path)
+
+	path, _, err = getApplicationName("./ping", cwd, os.Getenv("PATH"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	assertStr(t, expected, path)
+
+	path, _, err = getApplicationName(".\\ping", cwd, os.Getenv("PATH"))
 	if err != nil {
 		t.Fatal(err)
 	}
+	assertStr(t, expected, path)
 
 	// Test that we only find the first element of the commandline if the binary exists.
-	_, _, err = getApplicationName("ping test", cwd, os.Getenv("PATH"))
+	path, _, err = getApplicationName("ping test", cwd, os.Getenv("PATH"))
 	if err != nil {
 		t.Fatal(err)
 	}
+	assertStr(t, expected, path)
 
 	// Test quoted application name with an argument afterwards.
 	path, cmdLine, err := getApplicationName("\"ping\" 127.0.0.1", cwd, os.Getenv("PATH"))
 	if err != nil {
 		t.Fatal(err)
 	}
+	assertStr(t, expected, path)
 
 	args := splitArgs(cmdLine)
 	cmd := &exec.Cmd{