cmd: remove startsubsys command

SFTPGo is not designed to be used as an OpenSSH subsystem — many
features do not work correctly in subsystem mode. The functionality
was added after a user request in the pkg/sftp repository to
demonstrate that it was feasible, not for actual practical use.

Signed-off-by: Nicola Murino <[email protected]>

internal/cmd/startsubsys.go

@@ -1,227 +0,0 @@
-// Copyright (C) 2019 Nicola Murino
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published
-// by the Free Software Foundation, version 3.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program. If not, see <https://www.gnu.org/licenses/>.
-
-package cmd
-
-import (
-	"io"
-	"os"
-	"os/user"
-	"path/filepath"
-
-	"github.com/rs/xid"
-	"github.com/rs/zerolog"
-	"github.com/spf13/cobra"
-	"github.com/spf13/viper"
-
-	"github.com/drakkan/sftpgo/v2/internal/common"
-	"github.com/drakkan/sftpgo/v2/internal/config"
-	"github.com/drakkan/sftpgo/v2/internal/dataprovider"
-	"github.com/drakkan/sftpgo/v2/internal/logger"
-	"github.com/drakkan/sftpgo/v2/internal/plugin"
-	"github.com/drakkan/sftpgo/v2/internal/sftpd"
-	"github.com/drakkan/sftpgo/v2/internal/version"
-)
-
-var (
-	logJournalD     = false
-	preserveHomeDir = false
-	baseHomeDir     = ""
-	subsystemCmd    = &cobra.Command{
-		Use:   "startsubsys",
-		Short: "Use sftpgo as SFTP file transfer subsystem",
-		Long: `In this mode SFTPGo speaks the server side of SFTP protocol to stdout and
-expects client requests from stdin.
-This mode is not intended to be called directly, but from sshd using the
-Subsystem option.
-For example adding a line like this one in "/etc/ssh/sshd_config":
-
-Subsystem	sftp	sftpgo startsubsys
-
-Command-line flags should be specified in the Subsystem declaration.
-`,
-		Run: func(_ *cobra.Command, _ []string) {
-			logSender := "startsubsys"
-			connectionID := xid.New().String()
-			var zeroLogLevel zerolog.Level
-			switch logLevel {
-			case "info":
-				zeroLogLevel = zerolog.InfoLevel
-			case "warn":
-				zeroLogLevel = zerolog.WarnLevel
-			case "error":
-				zeroLogLevel = zerolog.ErrorLevel
-			default:
-				zeroLogLevel = zerolog.DebugLevel
-			}
-			logger.SetLogTime(logUTCTime)
-			if logJournalD {
-				logger.InitJournalDLogger(zeroLogLevel)
-			} else {
-				logger.InitStdErrLogger(zeroLogLevel)
-			}
-			osUser, err := user.Current()
-			if err != nil {
-				logger.Error(logSender, connectionID, "unable to get the current user: %v", err)
-				os.Exit(1)
-			}
-			username := osUser.Username
-			homedir := osUser.HomeDir
-			logger.Info(logSender, connectionID, "starting SFTPGo %v as subsystem, user %q home dir %q config dir %q base home dir %q",
-				version.Get(), username, homedir, configDir, baseHomeDir)
-			err = config.LoadConfig(configDir, configFile)
-			if err != nil {
-				logger.Error(logSender, connectionID, "unable to load configuration: %v", err)
-				os.Exit(1)
-			}
-			kmsConfig := config.GetKMSConfig()
-			if err := kmsConfig.Initialize(); err != nil {
-				logger.Error(logSender, connectionID, "unable to initialize KMS: %v", err)
-				os.Exit(1)
-			}
-			if err := plugin.Initialize(config.GetPluginsConfig(), logLevel); err != nil {
-				logger.Error(logSender, connectionID, "unable to initialize plugin system: %v", err)
-				os.Exit(1)
-			}
-			mfaConfig := config.GetMFAConfig()
-			err = mfaConfig.Initialize()
-			if err != nil {
-				logger.Error(logSender, "", "unable to initialize MFA: %v", err)
-				os.Exit(1)
-			}
-			dataProviderConf := config.GetProviderConf()
-			if dataProviderConf.Driver == dataprovider.SQLiteDataProviderName || dataProviderConf.Driver == dataprovider.BoltDataProviderName {
-				logger.Debug(logSender, connectionID, "data provider %q not supported in subsystem mode, using %q provider",
-					dataProviderConf.Driver, dataprovider.MemoryDataProviderName)
-				dataProviderConf.Driver = dataprovider.MemoryDataProviderName
-				dataProviderConf.Name = ""
-			}
-			config.SetProviderConf(dataProviderConf)
-			err = dataprovider.Initialize(dataProviderConf, configDir, false)
-			if err != nil {
-				logger.Error(logSender, connectionID, "unable to initialize the data provider: %v", err)
-				os.Exit(1)
-			}
-			smtpConfig := config.GetSMTPConfig()
-			err = smtpConfig.Initialize(configDir, false)
-			if err != nil {
-				logger.Error(logSender, connectionID, "unable to initialize SMTP configuration: %v", err)
-				os.Exit(1)
-			}
-			commonConfig := config.GetCommonConfig()
-			// idle connection are managed externally
-			commonConfig.IdleTimeout = 0
-			config.SetCommonConfig(commonConfig)
-			if err := common.Initialize(config.GetCommonConfig(), dataProviderConf.GetShared()); err != nil {
-				logger.Error(logSender, connectionID, "%v", err)
-				os.Exit(1)
-			}
-			httpConfig := config.GetHTTPConfig()
-			if err := httpConfig.Initialize(configDir); err != nil {
-				logger.Error(logSender, connectionID, "unable to initialize http client: %v", err)
-				os.Exit(1)
-			}
-			commandConfig := config.GetCommandConfig()
-			if err := commandConfig.Initialize(); err != nil {
-				logger.Error(logSender, connectionID, "unable to initialize commands configuration: %v", err)
-				os.Exit(1)
-			}
-			user, err := dataprovider.UserExists(username, "")
-			if err == nil {
-				if user.HomeDir != filepath.Clean(homedir) && !preserveHomeDir {
-					// update the user
-					user.HomeDir = filepath.Clean(homedir)
-					err = dataprovider.UpdateUser(&user, dataprovider.ActionExecutorSystem, "", "")
-					if err != nil {
-						logger.Error(logSender, connectionID, "unable to update user %q: %v", username, err)
-						os.Exit(1)
-					}
-				}
-			} else {
-				user.Username = username
-				if baseHomeDir != "" && filepath.IsAbs(baseHomeDir) {
-					user.HomeDir = filepath.Join(baseHomeDir, username)
-				} else {
-					user.HomeDir = filepath.Clean(homedir)
-				}
-				logger.Debug(logSender, connectionID, "home dir for new user %q", user.HomeDir)
-				user.Password = connectionID
-				user.Permissions = make(map[string][]string)
-				user.Permissions["/"] = []string{dataprovider.PermAny}
-				err = dataprovider.AddUser(&user, dataprovider.ActionExecutorSystem, "", "")
-				if err != nil {
-					logger.Error(logSender, connectionID, "unable to add user %q: %v", username, err)
-					os.Exit(1)
-				}
-			}
-			err = user.LoadAndApplyGroupSettings()
-			if err != nil {
-				logger.Error(logSender, connectionID, "unable to apply group settings for user %q: %v", username, err)
-				os.Exit(1)
-			}
-			err = sftpd.ServeSubSystemConnection(&user, connectionID, os.Stdin, os.Stdout)
-			if err != nil && err != io.EOF {
-				logger.Warn(logSender, connectionID, "serving subsystem finished with error: %v", err)
-				os.Exit(1)
-			}
-			logger.Info(logSender, connectionID, "serving subsystem finished")
-			plugin.Handler.Cleanup()
-			os.Exit(0)
-		},
-	}
-)
-
-func init() {
-	subsystemCmd.Flags().BoolVarP(&preserveHomeDir, "preserve-home", "p", false, `If the user already exists, the existing home
-directory will not be changed`)
-	subsystemCmd.Flags().StringVarP(&baseHomeDir, "base-home-dir", "d", "", `If the user does not exist specify an alternate
-starting directory. The home directory for a new
-user will be:
-
-[base-home-dir]/[username]
-
-base-home-dir must be an absolute path.`)
-	subsystemCmd.Flags().BoolVarP(&logJournalD, "log-to-journald", "j", false, `Send logs to journald. Only available on Linux.
-Use:
-
-$ journalctl -o verbose -f
-
-To see full logs.
-If not set, the logs will be sent to the standard
-error`)
-
-	addConfigFlags(subsystemCmd)
-
-	viper.SetDefault(logLevelKey, defaultLogLevel)
-	viper.BindEnv(logLevelKey, "SFTPGO_LOG_LEVEL") //nolint:errcheck
-	subsystemCmd.Flags().StringVar(&logLevel, logLevelFlag, viper.GetString(logLevelKey),
-		`Set the log level. Supported values:
-
-debug, info, warn, error.
-
-This flag can be set
-using SFTPGO_LOG_LEVEL env var too.
-`)
-	viper.BindPFlag(logLevelKey, subsystemCmd.Flags().Lookup(logLevelFlag)) //nolint:errcheck
-
-	viper.SetDefault(logUTCTimeKey, defaultLogUTCTime)
-	viper.BindEnv(logUTCTimeKey, "SFTPGO_LOG_UTC_TIME") //nolint:errcheck
-	subsystemCmd.Flags().BoolVar(&logUTCTime, logUTCTimeFlag, viper.GetBool(logUTCTimeKey),
-		`Use UTC time for logging. This flag can be set
-using SFTPGO_LOG_UTC_TIME env var too.
-`)
-	viper.BindPFlag(logUTCTimeKey, subsystemCmd.Flags().Lookup(logUTCTimeFlag)) //nolint:errcheck
-
-	rootCmd.AddCommand(subsystemCmd)
-}