add --env mode to mshell to print cwd and environment (for server initpk). needed because OSX does not support 'env -0'

main-mshell.go

@@ -425,6 +425,19 @@ func handleInstall() (int, error) {
 	return 0, nil
 }
 
+func handleEnv() (int, error) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		return 1, err
+	}
+	fmt.Printf("%s\x00", cwd)
+	fullEnv := os.Environ()
+	for _, envLine := range fullEnv {
+		fmt.Printf("%s\x00", envLine)
+	}
+	return 0, nil
+}
+
 func handleUsage() {
 	usage := `
 Client Usage: mshell [opts] --ssh user@host -- [command]
@@ -482,6 +495,14 @@ func main() {
 	} else if firstArg == "--version" {
 		fmt.Printf("mshell v%s\n", base.MShellVersion)
 		return
+	} else if firstArg == "--env" {
+		rtnCode, err := handleEnv()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "[error] %v\n", err)
+		}
+		if rtnCode != 0 {
+			os.Exit(rtnCode)
+		}
 	} else if firstArg == "--single" {
 		handleSingle()
 		return

pkg/packet/packet.go

@@ -433,16 +433,17 @@ func FmtMessagePacket(fmtStr string, args ...interface{}) *MessagePacketType {
 }
 
 type InitPacketType struct {
-	Type          string   `json:"type"`
-	Version       string   `json:"version"`
-	MShellHomeDir string   `json:"mshellhomedir,omitempty"`
-	HomeDir       string   `json:"homedir,omitempty"`
-	Env           []string `json:"env,omitempty"`
-	User          string   `json:"user,omitempty"`
-	HostName      string   `json:"hostname,omitempty"`
-	NotFound      bool     `json:"notfound,omitempty"`
-	UName         string   `json:"uname,omitempty"`
-	RemoteId      string   `json:"remoteid,omitempty"`
+	Type          string `json:"type"`
+	Version       string `json:"version"`
+	MShellHomeDir string `json:"mshellhomedir,omitempty"`
+	HomeDir       string `json:"homedir,omitempty"`
+	Cwd           string `json:"cwd,omitempty"`
+	Env           []byte `json:"env,omitempty"` // "env -0" format
+	User          string `json:"user,omitempty"`
+	HostName      string `json:"hostname,omitempty"`
+	NotFound      bool   `json:"notfound,omitempty"`
+	UName         string `json:"uname,omitempty"`
+	RemoteId      string `json:"remoteid,omitempty"`
 }
 
 func (*InitPacketType) GetType() string {

pkg/shexec/shexec.go

@@ -7,8 +7,10 @@
 package shexec
 
 import (
+	"bytes"
 	"context"
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -38,6 +40,8 @@ const FirstExtraFilesFdNum = 3
 const DefaultTermType = "xterm-256color"
 const DefaultMaxPtySize = 1024 * 1024
 
+const GetStateTimeout = 5 * time.Second
+
 const ClientCommand = `
 PATH=$PATH:~/.mshell;
 which mshell > /dev/null;
@@ -1095,10 +1099,70 @@ func MakeInitPacket() *packet.InitPacketType {
 func MakeServerInitPacket() (*packet.InitPacketType, error) {
 	var err error
 	initPacket := MakeInitPacket()
-	initPacket.Env = os.Environ()
+	cwd, env, err := GetCurrentState()
+	if err != nil {
+		return nil, err
+	}
+	initPacket.Cwd = cwd
+	initPacket.Env = env
 	initPacket.RemoteId, err = base.GetRemoteId()
 	if err != nil {
 		return nil, err
 	}
 	return initPacket, nil
 }
+
+func parseEnv(env []byte) map[string]string {
+	envLines := bytes.Split(env, []byte{0})
+	rtn := make(map[string]string)
+	for _, envLine := range envLines {
+		if len(envLine) == 0 {
+			continue
+		}
+		eqIdx := bytes.Index(envLine, []byte{'='})
+		if eqIdx == -1 {
+			continue
+		}
+		varName := string(envLine[0:eqIdx])
+		varVal := string(envLine[eqIdx+1:])
+		rtn[varName] = varVal
+	}
+	return rtn
+}
+
+func getStderr(err error) string {
+	exitErr, ok := err.(*exec.ExitError)
+	if !ok {
+		return ""
+	}
+	if len(exitErr.Stderr) == 0 {
+		return ""
+	}
+	lines := strings.SplitN(string(exitErr.Stderr), "\n", 2)
+	if len(lines[0]) > 100 {
+		return lines[0][0:100]
+	}
+	return lines[0]
+}
+
+func GetCurrentState() (string, []byte, error) {
+	execFile, err := os.Executable()
+	if err != nil {
+		return "", nil, fmt.Errorf("cannot find local mshell executable: %w", err)
+	}
+	ctx, _ := context.WithTimeout(context.Background(), GetStateTimeout)
+	ecmd := exec.CommandContext(ctx, "bash", "-l", "-c", fmt.Sprintf("%s --env", shellescape.Quote(execFile)))
+	outputBytes, err := ecmd.Output()
+	if err != nil {
+		errMsg := getStderr(err)
+		if errMsg != "" {
+			return "", nil, errors.New(errMsg)
+		}
+		return "", nil, err
+	}
+	idx := bytes.Index(outputBytes, []byte{0})
+	if idx == -1 {
+		return "", nil, fmt.Errorf("invalid current state output no NUL byte separator")
+	}
+	return string(outputBytes[0:idx]), outputBytes[idx+1:], nil
+}