github.com/coltonfike/e2c@v21.1.0+incompatible/node/config.go (about)

     1  // Copyright 2014 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package node
    18  
    19  import (
    20  	"crypto/ecdsa"
    21  	"fmt"
    22  	"io/ioutil"
    23  	"os"
    24  	"path/filepath"
    25  	"runtime"
    26  	"strings"
    27  	"sync"
    28  
    29  	"github.com/ethereum/go-ethereum/accounts"
    30  	"github.com/ethereum/go-ethereum/accounts/external"
    31  	"github.com/ethereum/go-ethereum/accounts/keystore"
    32  	"github.com/ethereum/go-ethereum/accounts/pluggable"
    33  	"github.com/ethereum/go-ethereum/accounts/scwallet"
    34  	"github.com/ethereum/go-ethereum/accounts/usbwallet"
    35  	"github.com/ethereum/go-ethereum/common"
    36  	"github.com/ethereum/go-ethereum/crypto"
    37  	"github.com/ethereum/go-ethereum/log"
    38  	"github.com/ethereum/go-ethereum/p2p"
    39  	"github.com/ethereum/go-ethereum/p2p/enode"
    40  	"github.com/ethereum/go-ethereum/params"
    41  	"github.com/ethereum/go-ethereum/plugin"
    42  	"github.com/ethereum/go-ethereum/rpc"
    43  )
    44  
    45  const (
    46  	datadirPrivateKey      = "nodekey"            // Path within the datadir to the node's private key
    47  	datadirDefaultKeyStore = "keystore"           // Path within the datadir to the keystore
    48  	datadirStaticNodes     = "static-nodes.json"  // Path within the datadir to the static node list
    49  	datadirTrustedNodes    = "trusted-nodes.json" // Path within the datadir to the trusted node list
    50  	datadirNodeDatabase    = "nodes"              // Path within the datadir to store the node infos
    51  )
    52  
    53  // Config represents a small collection of configuration values to fine tune the
    54  // P2P network layer of a protocol stack. These values can be further extended by
    55  // all registered services.
    56  type Config struct {
    57  	// Name sets the instance name of the node. It must not contain the / character and is
    58  	// used in the devp2p node identifier. The instance name of geth is "geth". If no
    59  	// value is specified, the basename of the current executable is used.
    60  	Name string `toml:"-"`
    61  
    62  	// UserIdent, if set, is used as an additional component in the devp2p node identifier.
    63  	UserIdent string `toml:",omitempty"`
    64  
    65  	// Version should be set to the version number of the program. It is used
    66  	// in the devp2p node identifier.
    67  	Version string `toml:"-"`
    68  
    69  	// DataDir is the file system folder the node should use for any data storage
    70  	// requirements. The configured data directory will not be directly shared with
    71  	// registered services, instead those can use utility methods to create/access
    72  	// databases or flat files. This enables ephemeral nodes which can fully reside
    73  	// in memory.
    74  	DataDir string
    75  
    76  	// Configuration of peer-to-peer networking.
    77  	P2P p2p.Config
    78  
    79  	// KeyStoreDir is the file system folder that contains private keys. The directory can
    80  	// be specified as a relative path, in which case it is resolved relative to the
    81  	// current directory.
    82  	//
    83  	// If KeyStoreDir is empty, the default location is the "keystore" subdirectory of
    84  	// DataDir. If DataDir is unspecified and KeyStoreDir is empty, an ephemeral directory
    85  	// is created by New and destroyed when the node is stopped.
    86  	KeyStoreDir string `toml:",omitempty"`
    87  
    88  	// ExternalSigner specifies an external URI for a clef-type signer
    89  	ExternalSigner string `toml:"omitempty"`
    90  
    91  	// UseLightweightKDF lowers the memory and CPU requirements of the key store
    92  	// scrypt KDF at the expense of security.
    93  	UseLightweightKDF bool `toml:",omitempty"`
    94  
    95  	// InsecureUnlockAllowed allows user to unlock accounts in unsafe http environment.
    96  	InsecureUnlockAllowed bool `toml:",omitempty"`
    97  
    98  	// NoUSB disables hardware wallet monitoring and connectivity.
    99  	NoUSB bool `toml:",omitempty"`
   100  
   101  	// SmartCardDaemonPath is the path to the smartcard daemon's socket
   102  	SmartCardDaemonPath string `toml:",omitempty"`
   103  
   104  	// IPCPath is the requested location to place the IPC endpoint. If the path is
   105  	// a simple file name, it is placed inside the data directory (or on the root
   106  	// pipe path on Windows), whereas if it's a resolvable path name (absolute or
   107  	// relative), then that specific path is enforced. An empty path disables IPC.
   108  	IPCPath string `toml:",omitempty"`
   109  
   110  	// HTTPHost is the host interface on which to start the HTTP RPC server. If this
   111  	// field is empty, no HTTP API endpoint will be started.
   112  	HTTPHost string `toml:",omitempty"`
   113  
   114  	// HTTPPort is the TCP port number on which to start the HTTP RPC server. The
   115  	// default zero value is/ valid and will pick a port number randomly (useful
   116  	// for ephemeral nodes).
   117  	HTTPPort int `toml:",omitempty"`
   118  
   119  	// HTTPCors is the Cross-Origin Resource Sharing header to send to requesting
   120  	// clients. Please be aware that CORS is a browser enforced security, it's fully
   121  	// useless for custom HTTP clients.
   122  	HTTPCors []string `toml:",omitempty"`
   123  
   124  	// HTTPVirtualHosts is the list of virtual hostnames which are allowed on incoming requests.
   125  	// This is by default {'localhost'}. Using this prevents attacks like
   126  	// DNS rebinding, which bypasses SOP by simply masquerading as being within the same
   127  	// origin. These attacks do not utilize CORS, since they are not cross-domain.
   128  	// By explicitly checking the Host-header, the server will not allow requests
   129  	// made against the server with a malicious host domain.
   130  	// Requests using ip address directly are not affected
   131  	HTTPVirtualHosts []string `toml:",omitempty"`
   132  
   133  	// HTTPModules is a list of API modules to expose via the HTTP RPC interface.
   134  	// If the module list is empty, all RPC API endpoints designated public will be
   135  	// exposed.
   136  	HTTPModules []string `toml:",omitempty"`
   137  
   138  	// HTTPTimeouts allows for customization of the timeout values used by the HTTP RPC
   139  	// interface.
   140  	HTTPTimeouts rpc.HTTPTimeouts
   141  
   142  	// WSHost is the host interface on which to start the websocket RPC server. If
   143  	// this field is empty, no websocket API endpoint will be started.
   144  	WSHost string `toml:",omitempty"`
   145  
   146  	// WSPort is the TCP port number on which to start the websocket RPC server. The
   147  	// default zero value is/ valid and will pick a port number randomly (useful for
   148  	// ephemeral nodes).
   149  	WSPort int `toml:",omitempty"`
   150  
   151  	// WSOrigins is the list of domain to accept websocket requests from. Please be
   152  	// aware that the server can only act upon the HTTP request the client sends and
   153  	// cannot verify the validity of the request header.
   154  	WSOrigins []string `toml:",omitempty"`
   155  
   156  	// WSModules is a list of API modules to expose via the websocket RPC interface.
   157  	// If the module list is empty, all RPC API endpoints designated public will be
   158  	// exposed.
   159  	WSModules []string `toml:",omitempty"`
   160  
   161  	// WSExposeAll exposes all API modules via the WebSocket RPC interface rather
   162  	// than just the public ones.
   163  	//
   164  	// *WARNING* Only set this if the node is running in a trusted network, exposing
   165  	// private APIs to untrusted users is a major security risk.
   166  	WSExposeAll bool `toml:",omitempty"`
   167  
   168  	// GraphQLHost is the host interface on which to start the GraphQL server. If this
   169  	// field is empty, no GraphQL API endpoint will be started.
   170  	GraphQLHost string `toml:",omitempty"`
   171  
   172  	// GraphQLPort is the TCP port number on which to start the GraphQL server. The
   173  	// default zero value is/ valid and will pick a port number randomly (useful
   174  	// for ephemeral nodes).
   175  	GraphQLPort int `toml:",omitempty"`
   176  
   177  	// GraphQLCors is the Cross-Origin Resource Sharing header to send to requesting
   178  	// clients. Please be aware that CORS is a browser enforced security, it's fully
   179  	// useless for custom HTTP clients.
   180  	GraphQLCors []string `toml:",omitempty"`
   181  
   182  	// GraphQLVirtualHosts is the list of virtual hostnames which are allowed on incoming requests.
   183  	// This is by default {'localhost'}. Using this prevents attacks like
   184  	// DNS rebinding, which bypasses SOP by simply masquerading as being within the same
   185  	// origin. These attacks do not utilize CORS, since they are not cross-domain.
   186  	// By explicitly checking the Host-header, the server will not allow requests
   187  	// made against the server with a malicious host domain.
   188  	// Requests using ip address directly are not affected
   189  	GraphQLVirtualHosts []string `toml:",omitempty"`
   190  
   191  	// Logger is a custom logger to use with the p2p.Server.
   192  	Logger log.Logger `toml:",omitempty"`
   193  
   194  	staticNodesWarning     bool
   195  	trustedNodesWarning    bool
   196  	oldGethResourceWarning bool
   197  	Plugins                *plugin.Settings `toml:",omitempty"`
   198  	// Quorum: EnableNodePermission comes from EnableNodePermissionFlag --permissioned.
   199  	EnableNodePermission bool `toml:",omitempty"`
   200  }
   201  
   202  // IPCEndpoint resolves an IPC endpoint based on a configured value, taking into
   203  // account the set data folders as well as the designated platform we're currently
   204  // running on.
   205  func (c *Config) IPCEndpoint() string {
   206  	// Short circuit if IPC has not been enabled
   207  	if c.IPCPath == "" {
   208  		return ""
   209  	}
   210  	// On windows we can only use plain top-level pipes
   211  	if runtime.GOOS == "windows" {
   212  		if strings.HasPrefix(c.IPCPath, `\\.\pipe\`) {
   213  			return c.IPCPath
   214  		}
   215  		return `\\.\pipe\` + c.IPCPath
   216  	}
   217  	// Resolve names into the data directory full paths otherwise
   218  	if filepath.Base(c.IPCPath) == c.IPCPath {
   219  		if c.DataDir == "" {
   220  			return filepath.Join(os.TempDir(), c.IPCPath)
   221  		}
   222  		return filepath.Join(c.DataDir, c.IPCPath)
   223  	}
   224  	return c.IPCPath
   225  }
   226  
   227  // NodeDB returns the path to the discovery node database.
   228  func (c *Config) NodeDB() string {
   229  	if c.DataDir == "" {
   230  		return "" // ephemeral
   231  	}
   232  	return c.ResolvePath(datadirNodeDatabase)
   233  }
   234  
   235  // DefaultIPCEndpoint returns the IPC path used by default.
   236  func DefaultIPCEndpoint(clientIdentifier string) string {
   237  	if clientIdentifier == "" {
   238  		clientIdentifier = strings.TrimSuffix(filepath.Base(os.Args[0]), ".exe")
   239  		if clientIdentifier == "" {
   240  			panic("empty executable name")
   241  		}
   242  	}
   243  	config := &Config{DataDir: DefaultDataDir(), IPCPath: clientIdentifier + ".ipc"}
   244  	return config.IPCEndpoint()
   245  }
   246  
   247  // HTTPEndpoint resolves an HTTP endpoint based on the configured host interface
   248  // and port parameters.
   249  func (c *Config) HTTPEndpoint() string {
   250  	if c.HTTPHost == "" {
   251  		return ""
   252  	}
   253  	return fmt.Sprintf("%s:%d", c.HTTPHost, c.HTTPPort)
   254  }
   255  
   256  // GraphQLEndpoint resolves a GraphQL endpoint based on the configured host interface
   257  // and port parameters.
   258  func (c *Config) GraphQLEndpoint() string {
   259  	if c.GraphQLHost == "" {
   260  		return ""
   261  	}
   262  	return fmt.Sprintf("%s:%d", c.GraphQLHost, c.GraphQLPort)
   263  }
   264  
   265  // DefaultHTTPEndpoint returns the HTTP endpoint used by default.
   266  func DefaultHTTPEndpoint() string {
   267  	config := &Config{HTTPHost: DefaultHTTPHost, HTTPPort: DefaultHTTPPort}
   268  	return config.HTTPEndpoint()
   269  }
   270  
   271  // WSEndpoint resolves a websocket endpoint based on the configured host interface
   272  // and port parameters.
   273  func (c *Config) WSEndpoint() string {
   274  	if c.WSHost == "" {
   275  		return ""
   276  	}
   277  	return fmt.Sprintf("%s:%d", c.WSHost, c.WSPort)
   278  }
   279  
   280  // DefaultWSEndpoint returns the websocket endpoint used by default.
   281  func DefaultWSEndpoint() string {
   282  	config := &Config{WSHost: DefaultWSHost, WSPort: DefaultWSPort}
   283  	return config.WSEndpoint()
   284  }
   285  
   286  // ExtRPCEnabled returns the indicator whether node enables the external
   287  // RPC(http, ws or graphql).
   288  func (c *Config) ExtRPCEnabled() bool {
   289  	return c.HTTPHost != "" || c.WSHost != "" || c.GraphQLHost != ""
   290  }
   291  
   292  // NodeName returns the devp2p node identifier.
   293  func (c *Config) NodeName() string {
   294  	name := c.name()
   295  	// Backwards compatibility: previous versions used title-cased "Geth", keep that.
   296  	if name == "geth" || name == "geth-testnet" {
   297  		name = "Geth"
   298  	}
   299  	if c.UserIdent != "" {
   300  		name += "/" + c.UserIdent
   301  	}
   302  	if c.Version != "" {
   303  		name += "/v" + c.Version
   304  	}
   305  	name += "/" + runtime.GOOS + "-" + runtime.GOARCH
   306  	name += "/" + runtime.Version()
   307  	return name
   308  }
   309  
   310  func (c *Config) name() string {
   311  	if c.Name == "" {
   312  		progname := strings.TrimSuffix(filepath.Base(os.Args[0]), ".exe")
   313  		if progname == "" {
   314  			panic("empty executable name, set Config.Name")
   315  		}
   316  		return progname
   317  	}
   318  	return c.Name
   319  }
   320  
   321  // These resources are resolved differently for "geth" instances.
   322  var isOldGethResource = map[string]bool{
   323  	"chaindata":          true,
   324  	"nodes":              true,
   325  	"nodekey":            true,
   326  	"static-nodes.json":  false, // no warning for these because they have their
   327  	"trusted-nodes.json": false, // own separate warning.
   328  }
   329  
   330  // ResolvePath resolves path in the instance directory.
   331  func (c *Config) ResolvePath(path string) string {
   332  	if filepath.IsAbs(path) {
   333  		return path
   334  	}
   335  	if c.DataDir == "" {
   336  		return ""
   337  	}
   338  	// Backwards-compatibility: ensure that data directory files created
   339  	// by geth 1.4 are used if they exist.
   340  	if warn, isOld := isOldGethResource[path]; isOld {
   341  		oldpath := ""
   342  		if c.name() == "geth" {
   343  			oldpath = filepath.Join(c.DataDir, path)
   344  		}
   345  		if oldpath != "" && common.FileExist(oldpath) {
   346  			if warn {
   347  				c.warnOnce(&c.oldGethResourceWarning, "Using deprecated resource file %s, please move this file to the 'geth' subdirectory of datadir.", oldpath)
   348  			}
   349  			return oldpath
   350  		}
   351  	}
   352  	return filepath.Join(c.instanceDir(), path)
   353  }
   354  
   355  func (c *Config) instanceDir() string {
   356  	if c.DataDir == "" {
   357  		return ""
   358  	}
   359  	return filepath.Join(c.DataDir, c.name())
   360  }
   361  
   362  // NodeKey retrieves the currently configured private key of the node, checking
   363  // first any manually set key, falling back to the one found in the configured
   364  // data folder. If no key can be found, a new one is generated.
   365  func (c *Config) NodeKey() *ecdsa.PrivateKey {
   366  	// Use any specifically configured key.
   367  	if c.P2P.PrivateKey != nil {
   368  		return c.P2P.PrivateKey
   369  	}
   370  	// Generate ephemeral key if no datadir is being used.
   371  	if c.DataDir == "" {
   372  		key, err := crypto.GenerateKey()
   373  		if err != nil {
   374  			log.Crit(fmt.Sprintf("Failed to generate ephemeral node key: %v", err))
   375  		}
   376  		return key
   377  	}
   378  
   379  	keyfile := c.ResolvePath(datadirPrivateKey)
   380  	if key, err := crypto.LoadECDSA(keyfile); err == nil {
   381  		return key
   382  	}
   383  	// No persistent key found, generate and store a new one.
   384  	key, err := crypto.GenerateKey()
   385  	if err != nil {
   386  		log.Crit(fmt.Sprintf("Failed to generate node key: %v", err))
   387  	}
   388  	instanceDir := filepath.Join(c.DataDir, c.name())
   389  	if err := os.MkdirAll(instanceDir, 0700); err != nil {
   390  		log.Error(fmt.Sprintf("Failed to persist node key: %v", err))
   391  		return key
   392  	}
   393  	keyfile = filepath.Join(instanceDir, datadirPrivateKey)
   394  	if err := crypto.SaveECDSA(keyfile, key); err != nil {
   395  		log.Error(fmt.Sprintf("Failed to persist node key: %v", err))
   396  	}
   397  	return key
   398  }
   399  
   400  // StaticNodes returns a list of node enode URLs configured as static nodes.
   401  func (c *Config) StaticNodes() []*enode.Node {
   402  	return c.parsePersistentNodes(&c.staticNodesWarning, c.ResolvePath(datadirStaticNodes))
   403  }
   404  
   405  // TrustedNodes returns a list of node enode URLs configured as trusted nodes.
   406  func (c *Config) TrustedNodes() []*enode.Node {
   407  	return c.parsePersistentNodes(&c.trustedNodesWarning, c.ResolvePath(datadirTrustedNodes))
   408  }
   409  
   410  // parsePersistentNodes parses a list of discovery node URLs loaded from a .json
   411  // file from within the data directory.
   412  func (c *Config) parsePersistentNodes(w *bool, path string) []*enode.Node {
   413  	// Short circuit if no node config is present
   414  	if c.DataDir == "" {
   415  		return nil
   416  	}
   417  	if _, err := os.Stat(path); err != nil {
   418  		return nil
   419  	}
   420  	c.warnOnce(w, "Found deprecated node list file %s, please use the TOML config file instead.", path)
   421  
   422  	// Load the nodes from the config file.
   423  	var nodelist []string
   424  	if err := common.LoadJSON(path, &nodelist); err != nil {
   425  		log.Error(fmt.Sprintf("Can't load node list file: %v", err))
   426  		return nil
   427  	}
   428  	// Interpret the list as a discovery node array
   429  	var nodes []*enode.Node
   430  	for _, url := range nodelist {
   431  		if url == "" {
   432  			continue
   433  		}
   434  		node, err := enode.Parse(enode.ValidSchemes, url)
   435  		if err != nil {
   436  			log.Error(fmt.Sprintf("Node URL %s: %v\n", url, err))
   437  			continue
   438  		}
   439  		nodes = append(nodes, node)
   440  	}
   441  	return nodes
   442  }
   443  
   444  // AccountConfig determines the settings for scrypt and keydirectory
   445  func (c *Config) AccountConfig() (int, int, string, error) {
   446  	scryptN := keystore.StandardScryptN
   447  	scryptP := keystore.StandardScryptP
   448  	if c.UseLightweightKDF {
   449  		scryptN = keystore.LightScryptN
   450  		scryptP = keystore.LightScryptP
   451  	}
   452  
   453  	var (
   454  		keydir string
   455  		err    error
   456  	)
   457  	switch {
   458  	case filepath.IsAbs(c.KeyStoreDir):
   459  		keydir = c.KeyStoreDir
   460  	case c.DataDir != "":
   461  		if c.KeyStoreDir == "" {
   462  			keydir = filepath.Join(c.DataDir, datadirDefaultKeyStore)
   463  		} else {
   464  			keydir, err = filepath.Abs(c.KeyStoreDir)
   465  		}
   466  	case c.KeyStoreDir != "":
   467  		keydir, err = filepath.Abs(c.KeyStoreDir)
   468  	}
   469  	return scryptN, scryptP, keydir, err
   470  }
   471  
   472  // Quorum
   473  //
   474  // Make sure plugin base dir exists
   475  func (c *Config) ResolvePluginBaseDir() error {
   476  	if c.Plugins == nil {
   477  		return nil
   478  	}
   479  	baseDir := c.Plugins.BaseDir.String()
   480  	if baseDir == "" {
   481  		baseDir = filepath.Join(c.DataDir, "plugins")
   482  	}
   483  	if !common.FileExist(baseDir) {
   484  		if err := os.MkdirAll(baseDir, 0755); err != nil {
   485  			return err
   486  		}
   487  	}
   488  	absBaseDir, err := filepath.Abs(baseDir)
   489  	if err != nil {
   490  		return err
   491  	}
   492  	c.Plugins.BaseDir = plugin.EnvironmentAwaredValue(absBaseDir)
   493  	return nil
   494  }
   495  
   496  // check if smart-contract-based permissioning is enabled by reading `--permissioned` flag and checking permission config file
   497  func (c *Config) IsPermissionEnabled() bool {
   498  	fullPath := filepath.Join(c.DataDir, params.PERMISSION_MODEL_CONFIG)
   499  	if _, err := os.Stat(fullPath); err != nil {
   500  		log.Warn(fmt.Sprintf("%s file is missing. Smart-contract-based permission service will be disabled", params.PERMISSION_MODEL_CONFIG), "error", err)
   501  		return false
   502  	}
   503  	return true
   504  }
   505  
   506  func makeAccountManager(conf *Config) (*accounts.Manager, string, error) {
   507  	scryptN, scryptP, keydir, err := conf.AccountConfig()
   508  	var ephemeral string
   509  	if keydir == "" {
   510  		// There is no datadir.
   511  		keydir, err = ioutil.TempDir("", "go-ethereum-keystore")
   512  		ephemeral = keydir
   513  	}
   514  
   515  	if err != nil {
   516  		return nil, "", err
   517  	}
   518  	if err := os.MkdirAll(keydir, 0700); err != nil {
   519  		return nil, "", err
   520  	}
   521  	// Assemble the account manager and supported backends
   522  	var backends []accounts.Backend
   523  	if len(conf.ExternalSigner) > 0 {
   524  		log.Info("Using external signer", "url", conf.ExternalSigner)
   525  		if extapi, err := external.NewExternalBackend(conf.ExternalSigner); err == nil {
   526  			backends = append(backends, extapi)
   527  		} else {
   528  			return nil, "", fmt.Errorf("error connecting to external signer: %v", err)
   529  		}
   530  	}
   531  	if len(backends) == 0 {
   532  		// For now, we're using EITHER external signer OR local signers.
   533  		// If/when we implement some form of lockfile for USB and keystore wallets,
   534  		// we can have both, but it's very confusing for the user to see the same
   535  		// accounts in both externally and locally, plus very racey.
   536  		backends = append(backends, keystore.NewKeyStore(keydir, scryptN, scryptP))
   537  		if !conf.NoUSB {
   538  			// Start a USB hub for Ledger hardware wallets
   539  			if ledgerhub, err := usbwallet.NewLedgerHub(); err != nil {
   540  				log.Warn(fmt.Sprintf("Failed to start Ledger hub, disabling: %v", err))
   541  			} else {
   542  				backends = append(backends, ledgerhub)
   543  			}
   544  			// Start a USB hub for Trezor hardware wallets (HID version)
   545  			if trezorhub, err := usbwallet.NewTrezorHubWithHID(); err != nil {
   546  				log.Warn(fmt.Sprintf("Failed to start HID Trezor hub, disabling: %v", err))
   547  			} else {
   548  				backends = append(backends, trezorhub)
   549  			}
   550  			// Start a USB hub for Trezor hardware wallets (WebUSB version)
   551  			if trezorhub, err := usbwallet.NewTrezorHubWithWebUSB(); err != nil {
   552  				log.Warn(fmt.Sprintf("Failed to start WebUSB Trezor hub, disabling: %v", err))
   553  			} else {
   554  				backends = append(backends, trezorhub)
   555  			}
   556  		}
   557  		if len(conf.SmartCardDaemonPath) > 0 {
   558  			// Start a smart card hub
   559  			if schub, err := scwallet.NewHub(conf.SmartCardDaemonPath, scwallet.Scheme, keydir); err != nil {
   560  				log.Warn(fmt.Sprintf("Failed to start smart card hub, disabling: %v", err))
   561  			} else {
   562  				backends = append(backends, schub)
   563  			}
   564  		}
   565  		if conf.Plugins != nil {
   566  			if _, ok := conf.Plugins.Providers[plugin.AccountPluginInterfaceName]; ok {
   567  				pluginBackend := pluggable.NewBackend()
   568  				backends = append(backends, pluginBackend)
   569  			}
   570  		}
   571  	}
   572  
   573  	return accounts.NewManager(&accounts.Config{InsecureUnlockAllowed: conf.InsecureUnlockAllowed}, backends...), ephemeral, nil
   574  }
   575  
   576  var warnLock sync.Mutex
   577  
   578  func (c *Config) warnOnce(w *bool, format string, args ...interface{}) {
   579  	warnLock.Lock()
   580  	defer warnLock.Unlock()
   581  
   582  	if *w {
   583  		return
   584  	}
   585  	l := c.Logger
   586  	if l == nil {
   587  		l = log.Root()
   588  	}
   589  	l.Warn(fmt.Sprintf(format, args...))
   590  	*w = true
   591  }