Turn chasquid-userdb into chasquid-util

This patch removes chasquid-userdb and adds a more generic and extensive
chasquid-util, that supports various operations on user databases as well as
aliases lookups.

The code is not very pretty but for now I took a more practical approach, the
tool is ancillary and can be tidied up later.

cmd/chasquid-util/chasquid-util.go

@@ -0,0 +1,198 @@
+// chasquid-util is a command-line utility for chasquid-related operations.
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"syscall"
+
+	"bytes"
+
+	"blitiri.com.ar/go/chasquid/internal/aliases"
+	"blitiri.com.ar/go/chasquid/internal/config"
+	"blitiri.com.ar/go/chasquid/internal/userdb"
+
+	"github.com/docopt/docopt-go"
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+// Usage, which doubles as parameter definitions thanks to docopt.
+const usage = `
+Usage:
+  chasquid-util adduser <db> <username> [--password=<password>]
+  chasquid-util removeuser <db> <username>
+  chasquid-util authenticate <db> <username> [--password=<password>]
+  chasquid-util check-userdb <db>
+  chasquid-util aliases-resolve <configdir> <address>
+`
+
+// Command-line arguments.
+var args map[string]interface{}
+
+func main() {
+	args, _ = docopt.Parse(usage, nil, true, "", false)
+
+	commands := map[string]func(){
+		"adduser":         AddUser,
+		"removeuser":      RemoveUser,
+		"authenticate":    Authenticate,
+		"check-userdb":    CheckUserDB,
+		"aliases-resolve": AliasesResolve,
+	}
+
+	for cmd, f := range commands {
+		if args[cmd].(bool) {
+			f()
+		}
+	}
+}
+
+func Fatalf(s string, arg ...interface{}) {
+	fmt.Printf(s+"\n", arg...)
+	os.Exit(1)
+}
+
+// chasquid-util check-userdb <db>
+func CheckUserDB() {
+	_, err := userdb.Load(args["<db>"].(string))
+	if err != nil {
+		Fatalf("Error loading database: %v", err)
+	}
+
+	fmt.Println("Database loaded")
+}
+
+// chasquid-util adduser <db> <username> [--password=<password>]
+func AddUser() {
+	db, err := userdb.Load(args["<db>"].(string))
+	if err != nil {
+		if os.IsNotExist(err) {
+			fmt.Println("Creating database")
+		} else {
+			Fatalf("Error loading database: %v", err)
+		}
+	}
+
+	password := getPassword()
+
+	err = db.AddUser(args["<username>"].(string), password)
+	if err != nil {
+		Fatalf("Error adding user: %v", err)
+	}
+
+	err = db.Write()
+	if err != nil {
+		Fatalf("Error writing database: %v", err)
+	}
+
+	fmt.Println("Added user")
+}
+
+// chasquid-util authenticate <db> <username> [--password=<password>]
+func Authenticate() {
+	db, err := userdb.Load(args["<db>"].(string))
+	if err != nil {
+		Fatalf("Error loading database: %v", err)
+	}
+
+	password := getPassword()
+	ok := db.Authenticate(args["<username>"].(string), password)
+	if ok {
+		fmt.Println("Authentication succeeded")
+	} else {
+		Fatalf("Authentication failed")
+	}
+}
+
+func getPassword() string {
+	password, ok := args["--password"].(string)
+	if ok {
+		return password
+	}
+
+	fmt.Printf("Password: ")
+	p1, err := terminal.ReadPassword(syscall.Stdin)
+	fmt.Printf("\n")
+	if err != nil {
+		Fatalf("Error reading password: %v\n", err)
+	}
+
+	fmt.Printf("Confirm password: ")
+	p2, err := terminal.ReadPassword(syscall.Stdin)
+	fmt.Printf("\n")
+	if err != nil {
+		Fatalf("Error reading password: %v", err)
+	}
+
+	if !bytes.Equal(p1, p2) {
+		Fatalf("Passwords don't match")
+	}
+
+	return string(p1)
+}
+
+// chasquid-util removeuser <db> <username>
+func RemoveUser() {
+	db, err := userdb.Load(args["<db>"].(string))
+	if err != nil {
+		Fatalf("Error loading database: %v", err)
+	}
+
+	present := db.RemoveUser(args["<username>"].(string))
+	if !present {
+		Fatalf("Unknown user")
+	}
+
+	err = db.Write()
+	if err != nil {
+		Fatalf("Error writing database: %v", err)
+	}
+
+	fmt.Println("Removed user")
+}
+
+// chasquid-util aliases-resolve <configdir> <address>
+func AliasesResolve() {
+	configDir := args["<configdir>"].(string)
+	conf, err := config.Load(configDir + "/chasquid.conf")
+	if err != nil {
+		Fatalf("Error reading config")
+	}
+	os.Chdir(configDir)
+
+	r := aliases.NewResolver()
+	r.SuffixSep = conf.SuffixSeparators
+	r.DropChars = conf.DropCharacters
+
+	domainDirs, err := ioutil.ReadDir("domains/")
+	if err != nil {
+		Fatalf("Error reading domains/ directory: %v", err)
+	}
+	if len(domainDirs) == 0 {
+		Fatalf("No domains found in config")
+	}
+
+	for _, info := range domainDirs {
+		name := info.Name()
+		aliasfile := "domains/" + name + "/aliases"
+		r.AddDomain(name)
+		err := r.AddAliasesFile(name, aliasfile)
+		if err == nil {
+			fmt.Printf("%s: loaded %q\n", name, aliasfile)
+		} else if err != nil && os.IsNotExist(err) {
+			fmt.Printf("%s: no aliases file\n", name)
+		} else {
+			fmt.Printf("%s: error loading %q: %v\n", name, aliasfile, err)
+		}
+	}
+
+	rcpts, err := r.Resolve(args["<address>"].(string))
+	if err != nil {
+		Fatalf("Error resolving: %v", err)
+	}
+	for _, rcpt := range rcpts {
+		fmt.Printf("%v  %s\n", rcpt.Type, rcpt.Addr)
+	}
+
+}