Auto-detect shell on Windows

Signed-off-by: Stefan Scherer <scherer_stefan@icloud.com>

commands/detectshell.go

@@ -0,0 +1,24 @@
+// +build !windows
+
+package commands
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func detectShell() (string, error) {
+	shell := os.Getenv("SHELL")
+
+	if shell == "" {
+		fmt.Printf("The default lines below are for a sh/bash shell, you can specify the shell you're using, with the --shell flag.\n\n")
+		return "", ErrUnknownShell
+	}
+
+	if os.Getenv("__fish_bin_dir") != "" {
+		return "fish", nil
+	}
+
+	return filepath.Base(shell), nil
+}

commands/detectshell_test.go

@@ -0,0 +1,29 @@
+package commands
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDetectBash(t *testing.T) {
+	originalShell := os.Getenv("SHELL")
+	os.Setenv("SHELL", "/bin/bash")
+	defer os.Setenv("SHELL", originalShell)
+	shell, err := detectShell()
+	assert.Nil(t, err)
+	assert.Equal(t, "bash", shell)
+}
+
+func TestDetectFish(t *testing.T) {
+	originalShell := os.Getenv("SHELL")
+	os.Setenv("SHELL", "/bin/bash")
+	defer os.Setenv("SHELL", originalShell)
+	originalFishdir := os.Getenv("__fish_bin_dir")
+	os.Setenv("__fish_bin_dir", "/usr/local/Cellar/fish/2.2.0/bin")
+	defer os.Setenv("__fish_bin_dir", originalFishdir)
+	shell, err := detectShell()
+	assert.Nil(t, err)
+	assert.Equal(t, "fish", shell)
+}

commands/detectshell_unix_test.go

@@ -0,0 +1,21 @@
+// +build !windows
+
+package commands
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnknowShell(t *testing.T) {
+	originalShell := os.Getenv("SHELL")
+	os.Setenv("SHELL", "")
+	defer os.Setenv("SHELL", originalShell)
+	shell, err := detectShell()
+	fmt.Println(shell)
+	assert.Equal(t, err, ErrUnknownShell)
+	assert.Equal(t, "", shell)
+}

commands/detectshell_windows.go

@@ -0,0 +1,76 @@
+package commands
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"unsafe"
+)
+
+// re-implementation of private function in https://github.com/golang/go/blob/master/src/syscall/syscall_windows.go#L945
+func getProcessEntry(pid int) (pe *syscall.ProcessEntry32, err error) {
+	snapshot, err := syscall.CreateToolhelp32Snapshot(syscall.TH32CS_SNAPPROCESS, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.CloseHandle(syscall.Handle(snapshot))
+
+	var processEntry syscall.ProcessEntry32
+	processEntry.Size = uint32(unsafe.Sizeof(processEntry))
+	err = syscall.Process32First(snapshot, &processEntry)
+	if err != nil {
+		return nil, err
+	}
+
+	for {
+		if processEntry.ProcessID == uint32(pid) {
+			pe = &processEntry
+			return
+		}
+
+		err = syscall.Process32Next(snapshot, &processEntry)
+		if err != nil {
+			return nil, err
+		}
+	}
+}
+
+// startedBy returns the exe file name of the parent process.
+func startedBy() (exefile string, err error) {
+	ppid := os.Getppid()
+
+	pe, err := getProcessEntry(ppid)
+	if err != nil {
+		return "", err
+	}
+
+	name := syscall.UTF16ToString(pe.ExeFile[:])
+	return name, nil
+}
+
+func detectShell() (string, error) {
+	shell := os.Getenv("SHELL")
+
+	if shell == "" {
+		shell, err := startedBy()
+		if err != nil {
+			return "cmd", err // defaulting to cmd
+		}
+		if strings.Contains(strings.ToLower(shell), "powershell") {
+			return "powershell", nil
+		} else if strings.Contains(strings.ToLower(shell), "cmd") {
+			return "cmd", nil
+		} else {
+			fmt.Printf("You can further specify your shell with either 'cmd' or 'powershell' with the --shell flag.\n\n")
+			return "cmd", nil // this could be either powershell or cmd, defaulting to cmd
+		}
+	}
+
+	if os.Getenv("__fish_bin_dir") != "" {
+		return "fish", nil
+	}
+
+	return filepath.Base(shell), nil
+}

commands/detectshell_windows_test.go

@@ -15,3 +15,10 @@ func TestDetect(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, "cmd", shell)
 }
+
+func TestStartedBy(t *testing.T) {
+	shell, err := startedBy()
+	assert.Nil(t, err)
+	assert.NotNil(t, shell)
+	assert.Equal(t, "go.exe", shell)
+}

commands/env.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"text/template"
 
@@ -251,22 +250,3 @@ func (g *EnvUsageHintGenerator) GenerateUsageHint(userShell string, args []strin
 
 	return fmt.Sprintf("%s Run this command to configure your shell: \n%s %s\n", comment, comment, cmd)
 }
-
-func detectShell() (string, error) {
-	shell := os.Getenv("SHELL")
-
-	if shell == "" {
-		if runtime.GOOS == "windows" {
-			fmt.Printf("You can further specify your shell with either 'cmd' or 'powershell' with the --shell flag.\n\n")
-			return "cmd", nil // this could be either powershell or cmd, defaulting to cmd
-		}
-		fmt.Printf("The default lines below are for a sh/bash shell, you can specify the shell you're using, with the --shell flag.\n\n")
-		return "", ErrUnknownShell
-	}
-
-	if os.Getenv("__fish_bin_dir") != "" {
-		return "fish", nil
-	}
-
-	return filepath.Base(shell), nil
-}

commands/env_test.go

@@ -5,8 +5,6 @@ import (
 	"path/filepath"
 	"testing"
 
-	"fmt"
-
 	"github.com/docker/machine/commands/commandstest"
 	"github.com/docker/machine/commands/mcndirs"
 	"github.com/docker/machine/drivers/fakedriver"
@@ -552,34 +550,3 @@ func TestShellCfgUnset(t *testing.T) {
 		os.Setenv(test.noProxyVar, "")
 	}
 }
-
-func TestDetectBash(t *testing.T) {
-	originalShell := os.Getenv("SHELL")
-	os.Setenv("SHELL", "/bin/bash")
-	defer os.Setenv("SHELL", originalShell)
-	shell, err := detectShell()
-	assert.Nil(t, err)
-	assert.Equal(t, "bash", shell)
-}
-
-func TestDetectFish(t *testing.T) {
-	originalShell := os.Getenv("SHELL")
-	os.Setenv("SHELL", "/bin/bash")
-	defer os.Setenv("SHELL", originalShell)
-	originalFishdir := os.Getenv("__fish_bin_dir")
-	os.Setenv("__fish_bin_dir", "/usr/local/Cellar/fish/2.2.0/bin")
-	defer os.Setenv("__fish_bin_dir", originalFishdir)
-	shell, err := detectShell()
-	assert.Nil(t, err)
-	assert.Equal(t, "fish", shell)
-}
-
-func TestUnknowShell(t *testing.T) {
-	originalShell := os.Getenv("SHELL")
-	os.Setenv("SHELL", "")
-	defer os.Setenv("SHELL", originalShell)
-	shell, err := detectShell()
-	fmt.Println(shell)
-	assert.Equal(t, err, ErrUnknownShell)
-	assert.Equal(t, "", shell)
-}