mirror of https://github.com/slackhq/nebula.git
162 lines
3.4 KiB
Go
162 lines
3.4 KiB
Go
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package sshd
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import (
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"errors"
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"flag"
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"fmt"
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"github.com/armon/go-radix"
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"sort"
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"strings"
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)
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// CommandFlags is a function called before help or command execution to parse command line flags
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// It should return a flag.FlagSet instance and a pointer to the struct that will contain parsed flags
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type CommandFlags func() (*flag.FlagSet, interface{})
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// CommandCallback is the function called when your command should execute.
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// fs will be a a pointer to the struct provided by Command.Flags callback, if there was one. -h and -help are reserved
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// and handled automatically for you.
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// a will be any unconsumed arguments, if no Command.Flags was available this will be all the flags passed in.
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// w is the writer to use when sending messages back to the client.
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// If an error is returned by the callback it is logged locally, the callback should handle messaging errors to the user
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// where appropriate
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type CommandCallback func(fs interface{}, a []string, w StringWriter) error
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type Command struct {
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Name string
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ShortDescription string
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Help string
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Flags CommandFlags
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Callback CommandCallback
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}
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func execCommand(c *Command, args []string, w StringWriter) error {
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var (
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fl *flag.FlagSet
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fs interface{}
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)
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if c.Flags != nil {
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fl, fs = c.Flags()
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if fl != nil {
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//TODO: handle the error
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fl.Parse(args)
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args = fl.Args()
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}
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}
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return c.Callback(fs, args, w)
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}
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func dumpCommands(c *radix.Tree, w StringWriter) {
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err := w.WriteLine("Available commands:")
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if err != nil {
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//TODO: log
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return
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}
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cmds := make([]string, 0)
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for _, l := range allCommands(c) {
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cmds = append(cmds, fmt.Sprintf("%s - %s", l.Name, l.ShortDescription))
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}
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sort.Strings(cmds)
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err = w.Write(strings.Join(cmds, "\n") + "\n\n")
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if err != nil {
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//TODO: log
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}
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}
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func lookupCommand(c *radix.Tree, sCmd string) (*Command, error) {
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cmd, ok := c.Get(sCmd)
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if !ok {
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return nil, nil
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}
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command, ok := cmd.(*Command)
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if !ok {
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return nil, errors.New("failed to cast command")
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}
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return command, nil
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}
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func matchCommand(c *radix.Tree, cmd string) []string {
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cmds := make([]string, 0)
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c.WalkPrefix(cmd, func(found string, v interface{}) bool {
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cmds = append(cmds, found)
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return false
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})
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sort.Strings(cmds)
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return cmds
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}
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func allCommands(c *radix.Tree) []*Command {
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cmds := make([]*Command, 0)
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c.WalkPrefix("", func(found string, v interface{}) bool {
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cmd, ok := v.(*Command)
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if ok {
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cmds = append(cmds, cmd)
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}
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return false
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})
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return cmds
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}
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func helpCallback(commands *radix.Tree, a []string, w StringWriter) (err error) {
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// Just typed help
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if len(a) == 0 {
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dumpCommands(commands, w)
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return nil
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}
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// We are printing a specific commands help text
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cmd, err := lookupCommand(commands, a[0])
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if err != nil {
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//TODO: handle error
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//TODO: message the user
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return
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}
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if cmd != nil {
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err = w.WriteLine(fmt.Sprintf("%s - %s", cmd.Name, cmd.ShortDescription))
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if err != nil {
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return err
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}
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if cmd.Help != "" {
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err = w.WriteLine(fmt.Sprintf(" %s", cmd.Help))
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if err != nil {
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return err
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}
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}
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if cmd.Flags != nil {
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fs, _ := cmd.Flags()
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if fs != nil {
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fs.SetOutput(w.GetWriter())
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fs.PrintDefaults()
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}
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}
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return nil
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}
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err = w.WriteLine("Command not available " + a[0])
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if err != nil {
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return err
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}
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return nil
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}
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func checkHelpArgs(args []string) bool {
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for _, a := range args {
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if a == "-h" || a == "-help" {
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return true
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}
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}
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return false
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}
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