Hack in command-line specification of domain, cert and key

.gitignore

@@ -1,2 +1,4 @@
 /crockery
 /crockery.db
+/cert
+/key

README.md

@@ -72,6 +72,18 @@ Probably other stuff. Email is big, and just keeps getting bigger.
 
 ## How
 
+### Building a binary
+
+```
+$ go build ur.gs/crockery/cmd/crockery
+$ sudo setcap 'cap_net_bind_service=+ep' ./crockery
+```
+
+The second step allows crockery to bind to the various low-numbered ports it
+needs (25, 587, 149, 993) **without** running as root. Don't bother with it if
+you're going to be running crockery as root, e.g., as a container or a single-
+purpose system.
+
 ### Initialize a new database
 
 ```

cmd/crockery/main.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
+	"flag"
 	"log"
 	"os"
 	"os/signal"
@@ -10,7 +12,19 @@ import (
 	"ur.gs/crockery/internal/store"
 )
 
+var (
+	domain   = flag.String("domain", "", "Domain to serve email for")
+	certFile = flag.String("cert", "", "Path to a PEM-encoded certificate bundle for TLS support")
+	keyFile  = flag.String("key", "", "Path to a PEM-encoded key for TLS support")
+)
+
 func main() {
+	flag.Parse()
+
+	if *domain == "" {
+		log.Fatal("A domain must be specified on the command line (for now!)")
+	}
+
 	ctx, cancel := context.WithCancel(context.Background())
 
 	datastore, err := store.New(ctx, "crockery.db")
@@ -18,6 +32,25 @@ func main() {
 		log.Fatal("Couldn't open crockery.db:", err)
 	}
 
+	// FIXME: This will eventually come from the datastore itself, via `crockery init`
+	datastore.SetDomain(*domain)
+	log.Printf("Running as %s", datastore.Domain())
+
+	// FIXME: This will eventually come from the datastore itself, via ACME
+	if *certFile != "" || *keyFile != "" {
+		cert, err := tls.LoadX509KeyPair(*certFile, *keyFile)
+		if err != nil {
+			log.Fatalf("Couldn't setup TLS: %v", err)
+		}
+
+		if cert.PrivateKey == nil {
+			log.Fatal("No private key for TLS certificate")
+		}
+
+		datastore.SetTLS(cert)
+		log.Print("Successfully loaded TLS certificate and key")
+	}
+
 	srv, err := services.New(ctx, datastore)
 	if err != nil {
 		log.Fatal("Couldn't start services:", err)

internal/imap/server.go

@@ -19,11 +19,13 @@ type Server interface {
 
 func NewServer(cancel context.CancelFunc, datastore store.Interface, starttls bool) Server {
 	out := &concrete{
-		cancel: cancel,
+		cancel:   cancel,
-		store:  datastore,
+		store:    datastore,
+		starttls: starttls,
 	}
 
 	out.server = imapserver.New(out)
+	out.server.TLSConfig = out.store.TLSConfig()
 
 	if starttls {
 		out.server.Addr = ":143"
@@ -35,13 +37,22 @@ func NewServer(cancel context.CancelFunc, datastore store.Interface, starttls bo
 }
 
 type concrete struct {
-	cancel context.CancelFunc
+	cancel   context.CancelFunc
-	store  store.Interface
+	store    store.Interface
-	server *imapserver.Server
+	server   *imapserver.Server
+	starttls bool
 }
 
 func (c *concrete) Run() {
-	if err := c.server.ListenAndServe(); err != nil {
+	var err error
+
+	if c.starttls {
+		err = c.server.ListenAndServe()
+	} else {
+		err = c.server.ListenAndServeTLS()
+	}
+
+	if err != nil {
 		log.Printf("Error serving IMAP %s: %v", c.server.Addr, err)
 	} else {
 		log.Printf("Stopped listening on IMAP %s", c.server.Addr)
@@ -56,7 +67,7 @@ func (c *concrete) Login(string, string) (imapbackend.User, error) {
 }
 
 func (c *concrete) Close() error {
-	c.cancel()  // FIXME: this doesn't touch the server
+	c.cancel() // FIXME: this doesn't touch the server
 
 	return nil
 }

internal/smtp/server.go

@@ -24,6 +24,7 @@ func NewServer(cancel context.CancelFunc, datastore store.Interface, submission
 
 	out.server = smtp.NewServer(out)
 	out.server.Domain = datastore.Domain()
+	out.server.TLSConfig = datastore.TLSConfig()
 
 	if submission {
 		out.server.Addr = ":587"

internal/store/store.go

@@ -2,20 +2,60 @@ package store
 
 import (
 	"context"
+	"crypto/tls"
 )
 
 type Interface interface {
 	Domain() string
+	TLS() tls.Certificate
+	TLSConfig() *tls.Config
+
+	SetDomain(string)
+	SetTLS(tls.Certificate)
 }
 
 func New(ctx context.Context, filename string) (Interface, error) {
-	return &concrete{domain: "example.com"}, nil
+	return &concrete{
+		filename: filename,
+	}, nil
 }
 
 type concrete struct {
+	filename string
+
+	// TODO: these will eventually be persisted to the file in `filename`
 	domain string
+	cert   tls.Certificate
 }
 
 func (c *concrete) Domain() string {
 	return c.domain
 }
+
+func (c *concrete) TLS() tls.Certificate {
+	return c.cert
+}
+
+func (c *concrete) TLSConfig() *tls.Config {
+	return &tls.Config{
+		GetCertificate: func(*tls.ClientHelloInfo) (*tls.Certificate, error) {
+			certCopy := c.TLS()
+
+			return &certCopy, nil
+		},
+
+		ServerName: c.Domain(),
+	}
+}
+
+func (c *concrete) SetDomain(domain string) {
+	c.domain = domain
+
+	return
+}
+
+func (c *concrete) SetTLS(cert tls.Certificate) {
+	c.cert = cert
+
+	return
+}