Refactor server certificates

4 files changed, 265 insertions, 285 deletions

diff --git a/examples/auth.go b/examples/auth.go
index eb7b129..4d61ea2 100644
--- a/examples/auth.go
+++ b/examples/auth.go
@@ -41,7 +41,7 @@ func main() {
 	mux.HandleFunc("/logout", logout)
 
 	var server gemini.Server
-	if err := server.CertificateStore.Load("/var/lib/gemini/certs"); err != nil {
+	if err := server.Certificates.Load("/var/lib/gemini/certs"); err != nil {
 		log.Fatal(err)
 	}
 	server.Register("localhost", &mux)
diff --git a/examples/server.go b/examples/server.go
index 11ea9ed..6c29cdd 100644
--- a/examples/server.go
+++ b/examples/server.go
@@ -3,54 +3,38 @@
 package main
 
 import (
-	"bytes"
+	"crypto"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
+	"io"
 	"log"
 	"os"
 	"time"
 
-	gmi "git.sr.ht/~adnano/go-gemini"
+	"git.sr.ht/~adnano/go-gemini"
 )
 
 func main() {
-	var server gmi.Server
-	if err := server.CertificateStore.Load("/var/lib/gemini/certs"); err != nil {
+	var server gemini.Server
+	if err := server.Certificates.Load("/var/lib/gemini/certs"); err != nil {
 		log.Fatal(err)
 	}
-	server.GetCertificate = func(hostname string, store *gmi.CertificateStore) *tls.Certificate {
-		cert, err := store.Lookup(hostname)
-		if err != nil {
-			switch err {
-			case gmi.ErrCertificateExpired:
-				// Generate a new certificate if the current one is expired.
-				log.Print("Old certificate expired, creating new one")
-				fallthrough
-			case gmi.ErrCertificateUnknown:
-				// Generate a certificate if one does not exist.
-				cert, err := gmi.CreateCertificate(gmi.CertificateOptions{
-					DNSNames: []string{hostname},
-					Duration: time.Hour,
-				})
-				if err != nil {
-					// Failed to generate new certificate, abort
-					return nil
-				}
-				// Store and return the new certificate
-				err = writeCertificate("/var/lib/gemini/certs/"+hostname, cert)
-				if err != nil {
-					return nil
-				}
-				store.Add(hostname, cert)
-				return &cert
-			}
+	server.CreateCertificate = func(hostname string) (tls.Certificate, error) {
+		fmt.Println("Generating certificate for", hostname)
+		cert, err := gemini.CreateCertificate(gemini.CertificateOptions{
+			DNSNames: []string{hostname},
+			Duration: time.Minute, // for testing purposes
+		})
+		if err == nil {
+			// Write the new certificate to disk
+			err = writeCertificate("/var/lib/gemini/certs/"+hostname, cert)
 		}
-		return cert
+		return cert, err
 	}
 
-	var mux gmi.ServeMux
-	mux.Handle("/", gmi.FileServer(gmi.Dir("/var/www")))
+	var mux gemini.ServeMux
+	mux.Handle("/", gemini.FileServer(gemini.Dir("/var/www")))
 
 	server.Register("localhost", &mux)
 	if err := server.ListenAndServe(); err != nil {
@@ -61,22 +45,13 @@ func main() {
 // writeCertificate writes the provided certificate and private key
 // to path.crt and path.key respectively.
 func writeCertificate(path string, cert tls.Certificate) error {
-	crt, err := marshalX509Certificate(cert.Leaf.Raw)
-	if err != nil {
-		return err
-	}
-	key, err := marshalPrivateKey(cert.PrivateKey)
-	if err != nil {
-		return err
-	}
-
 	// Write the certificate
 	crtPath := path + ".crt"
 	crtOut, err := os.OpenFile(crtPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
 		return err
 	}
-	if _, err := crtOut.Write(crt); err != nil {
+	if err := marshalX509Certificate(crtOut, cert.Leaf.Raw); err != nil {
 		return err
 	}
 
@@ -86,30 +61,19 @@ func writeCertificate(path string, cert tls.Certificate) error {
 	if err != nil {
 		return err
 	}
-	if _, err := keyOut.Write(key); err != nil {
-		return err
-	}
-	return nil
+	return marshalPrivateKey(keyOut, cert.PrivateKey)
 }
 
-// marshalX509Certificate returns a PEM-encoded version of the given raw certificate.
-func marshalX509Certificate(cert []byte) ([]byte, error) {
-	var b bytes.Buffer
-	if err := pem.Encode(&b, &pem.Block{Type: "CERTIFICATE", Bytes: cert}); err != nil {
-		return nil, err
-	}
-	return b.Bytes(), nil
+// marshalX509Certificate writes a PEM-encoded version of the given certificate.
+func marshalX509Certificate(w io.Writer, cert []byte) error {
+	return pem.Encode(w, &pem.Block{Type: "CERTIFICATE", Bytes: cert})
 }
 
-// marshalPrivateKey returns PEM encoded versions of the given certificate and private key.
-func marshalPrivateKey(priv interface{}) ([]byte, error) {
-	var b bytes.Buffer
+// marshalPrivateKey writes a PEM-encoded version of the given private key.
+func marshalPrivateKey(w io.Writer, priv crypto.PrivateKey) error {
 	privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
 	if err != nil {
-		return nil, err
-	}
-	if err := pem.Encode(&b, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
-		return nil, err
+		return err
 	}
-	return b.Bytes(), nil
+	return pem.Encode(w, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes})
 }
diff --git a/mux.go b/mux.go
new file mode 100644
index 0000000..47aa618
--- /dev/null
+++ b/mux.go
@@ -0,0 +1,210 @@
+package gemini
+
+import (
+	"net/url"
+	"path"
+	"sort"
+	"strings"
+	"sync"
+)
+
+// The following code is modified from the net/http package.
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// ServeMux is a Gemini request multiplexer.
+// It matches the URL of each incoming request against a list of registered
+// patterns and calls the handler for the pattern that
+// most closely matches the URL.
+//
+// Patterns name fixed, rooted paths, like "/favicon.ico",
+// or rooted subtrees, like "/images/" (note the trailing slash).
+// Longer patterns take precedence over shorter ones, so that
+// if there are handlers registered for both "/images/"
+// and "/images/thumbnails/", the latter handler will be
+// called for paths beginning "/images/thumbnails/" and the
+// former will receive requests for any other paths in the
+// "/images/" subtree.
+//
+// Note that since a pattern ending in a slash names a rooted subtree,
+// the pattern "/" matches all paths not matched by other registered
+// patterns, not just the URL with Path == "/".
+//
+// If a subtree has been registered and a request is received naming the
+// subtree root without its trailing slash, ServeMux redirects that
+// request to the subtree root (adding the trailing slash). This behavior can
+// be overridden with a separate registration for the path without
+// the trailing slash. For example, registering "/images/" causes ServeMux
+// to redirect a request for "/images" to "/images/", unless "/images" has
+// been registered separately.
+//
+// ServeMux also takes care of sanitizing the URL request path and
+// redirecting any request containing . or .. elements or repeated slashes
+// to an equivalent, cleaner URL.
+type ServeMux struct {
+	mu sync.RWMutex
+	m  map[string]muxEntry
+	es []muxEntry // slice of entries sorted from longest to shortest.
+}
+
+type muxEntry struct {
+	r       Responder
+	pattern string
+}
+
+// cleanPath returns the canonical path for p, eliminating . and .. elements.
+func cleanPath(p string) string {
+	if p == "" {
+		return "/"
+	}
+	if p[0] != '/' {
+		p = "/" + p
+	}
+	np := path.Clean(p)
+	// path.Clean removes trailing slash except for root;
+	// put the trailing slash back if necessary.
+	if p[len(p)-1] == '/' && np != "/" {
+		// Fast path for common case of p being the string we want:
+		if len(p) == len(np)+1 && strings.HasPrefix(p, np) {
+			np = p
+		} else {
+			np += "/"
+		}
+	}
+	return np
+}
+
+// Find a handler on a handler map given a path string.
+// Most-specific (longest) pattern wins.
+func (mux *ServeMux) match(path string) Responder {
+	// Check for exact match first.
+	v, ok := mux.m[path]
+	if ok {
+		return v.r
+	}
+
+	// Check for longest valid match.  mux.es contains all patterns
+	// that end in / sorted from longest to shortest.
+	for _, e := range mux.es {
+		if strings.HasPrefix(path, e.pattern) {
+			return e.r
+		}
+	}
+	return nil
+}
+
+// redirectToPathSlash determines if the given path needs appending "/" to it.
+// This occurs when a handler for path + "/" was already registered, but
+// not for path itself. If the path needs appending to, it creates a new
+// URL, setting the path to u.Path + "/" and returning true to indicate so.
+func (mux *ServeMux) redirectToPathSlash(path string, u *url.URL) (*url.URL, bool) {
+	mux.mu.RLock()
+	shouldRedirect := mux.shouldRedirectRLocked(path)
+	mux.mu.RUnlock()
+	if !shouldRedirect {
+		return u, false
+	}
+	path = path + "/"
+	u = &url.URL{Path: path, RawQuery: u.RawQuery}
+	return u, true
+}
+
+// shouldRedirectRLocked reports whether the given path and host should be redirected to
+// path+"/". This should happen if a handler is registered for path+"/" but
+// not path -- see comments at ServeMux.
+func (mux *ServeMux) shouldRedirectRLocked(path string) bool {
+	if _, exist := mux.m[path]; exist {
+		return false
+	}
+
+	n := len(path)
+	if n == 0 {
+		return false
+	}
+	if _, exist := mux.m[path+"/"]; exist {
+		return path[n-1] != '/'
+	}
+
+	return false
+}
+
+// Respond dispatches the request to the responder whose
+// pattern most closely matches the request URL.
+func (mux *ServeMux) Respond(w *ResponseWriter, r *Request) {
+	path := cleanPath(r.URL.Path)
+
+	// If the given path is /tree and its handler is not registered,
+	// redirect for /tree/.
+	if u, ok := mux.redirectToPathSlash(path, r.URL); ok {
+		Redirect(w, u.String())
+		return
+	}
+
+	if path != r.URL.Path {
+		u := *r.URL
+		u.Path = path
+		Redirect(w, u.String())
+		return
+	}
+
+	mux.mu.RLock()
+	defer mux.mu.RUnlock()
+
+	resp := mux.match(path)
+	if resp == nil {
+		w.WriteStatus(StatusNotFound)
+		return
+	}
+	resp.Respond(w, r)
+}
+
+// Handle registers the responder for the given pattern.
+// If a responder already exists for pattern, Handle panics.
+func (mux *ServeMux) Handle(pattern string, responder Responder) {
+	mux.mu.Lock()
+	defer mux.mu.Unlock()
+
+	if pattern == "" {
+		panic("gemini: invalid pattern")
+	}
+	if responder == nil {
+		panic("gemini: nil responder")
+	}
+	if _, exist := mux.m[pattern]; exist {
+		panic("gemini: multiple registrations for " + pattern)
+	}
+
+	if mux.m == nil {
+		mux.m = make(map[string]muxEntry)
+	}
+	e := muxEntry{responder, pattern}
+	mux.m[pattern] = e
+	if pattern[len(pattern)-1] == '/' {
+		mux.es = appendSorted(mux.es, e)
+	}
+}
+
+func appendSorted(es []muxEntry, e muxEntry) []muxEntry {
+	n := len(es)
+	i := sort.Search(n, func(i int) bool {
+		return len(es[i].pattern) < len(e.pattern)
+	})
+	if i == n {
+		return append(es, e)
+	}
+	// we now know that i points at where we want to insert
+	es = append(es, muxEntry{}) // try to grow the slice in place, any entry works.
+	copy(es[i+1:], es[i:])      // move shorter entries down
+	es[i] = e
+	return es
+}
+
+// HandleFunc registers the responder function for the given pattern.
+func (mux *ServeMux) HandleFunc(pattern string, responder func(*ResponseWriter, *Request)) {
+	if responder == nil {
+		panic("gemini: nil responder")
+	}
+	mux.Handle(pattern, ResponderFunc(responder))
+}
diff --git a/server.go b/server.go
index 65e62b5..f991f08 100644
--- a/server.go
+++ b/server.go
@@ -7,11 +7,8 @@ import (
 	"log"
 	"net"
 	"net/url"
-	"path"
-	"sort"
 	"strconv"
 	"strings"
-	"sync"
 	"time"
 )
 
@@ -21,13 +18,12 @@ type Server struct {
 	// If Addr is empty, the server will listen on the address ":1965".
 	Addr string
 
-	// CertificateStore contains the certificates used by the server.
-	CertificateStore CertificateStore
+	// Certificates contains the certificates used by the server.
+	Certificates CertificateStore
 
-	// GetCertificate, if not nil, will be called to retrieve the certificate
-	// to use for a given hostname.
-	// If the certificate is nil, the connection will be aborted.
-	GetCertificate func(hostname string, store *CertificateStore) *tls.Certificate
+	// CreateCertificate, if not nil, will be called to create a new certificate
+	// if the current one is expired or missing.
+	CreateCertificate func(hostname string) (tls.Certificate, error)
 
 	// registered responders
 	responders map[responderKey]Responder
@@ -69,6 +65,9 @@ func (s *Server) Register(pattern string, responder Responder) {
 		key.wildcard = true
 	}
 
+	if _, ok := s.responders[key]; ok {
+		panic("gemini: multiple registrations for " + pattern)
+	}
 	s.responders[key] = responder
 }
 
@@ -90,18 +89,11 @@ func (s *Server) ListenAndServe() error {
 	}
 	defer ln.Close()
 
-	config := &tls.Config{
-		ClientAuth: tls.RequestClientCert,
-		MinVersion: tls.VersionTLS12,
-		GetCertificate: func(h *tls.ClientHelloInfo) (*tls.Certificate, error) {
-			if s.GetCertificate != nil {
-				return s.GetCertificate(h.ServerName, &s.CertificateStore), nil
-			}
-			return s.CertificateStore.Lookup(h.ServerName)
-		},
-	}
-	tlsListener := tls.NewListener(ln, config)
-	return s.Serve(tlsListener)
+	return s.Serve(tls.NewListener(ln, &tls.Config{
+		ClientAuth:     tls.RequestClientCert,
+		MinVersion:     tls.VersionTLS12,
+		GetCertificate: s.getCertificate,
+	}))
 }
 
 // Serve listens for requests on the provided listener.
@@ -135,6 +127,21 @@ func (s *Server) Serve(l net.Listener) error {
 	}
 }
 
+func (s *Server) getCertificate(h *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	cert, err := s.Certificates.Lookup(h.ServerName)
+	switch err {
+	case ErrCertificateExpired, ErrCertificateUnknown:
+		if s.CreateCertificate != nil {
+			cert, err := s.CreateCertificate(h.ServerName)
+			if err == nil {
+				s.Certificates.Add(h.ServerName, cert)
+			}
+			return &cert, err
+		}
+	}
+	return cert, err
+}
+
 // respond responds to a connection.
 func (s *Server) respond(conn net.Conn) {
 	r := bufio.NewReader(conn)
@@ -317,204 +324,3 @@ type ResponderFunc func(*ResponseWriter, *Request)
 func (f ResponderFunc) Respond(w *ResponseWriter, r *Request) {
 	f(w, r)
 }
-
-// The following code is modified from the net/http package.
-
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// ServeMux is a Gemini request multiplexer.
-// It matches the URL of each incoming request against a list of registered
-// patterns and calls the handler for the pattern that
-// most closely matches the URL.
-//
-// Patterns name fixed, rooted paths, like "/favicon.ico",
-// or rooted subtrees, like "/images/" (note the trailing slash).
-// Longer patterns take precedence over shorter ones, so that
-// if there are handlers registered for both "/images/"
-// and "/images/thumbnails/", the latter handler will be
-// called for paths beginning "/images/thumbnails/" and the
-// former will receive requests for any other paths in the
-// "/images/" subtree.
-//
-// Note that since a pattern ending in a slash names a rooted subtree,
-// the pattern "/" matches all paths not matched by other registered
-// patterns, not just the URL with Path == "/".
-//
-// If a subtree has been registered and a request is received naming the
-// subtree root without its trailing slash, ServeMux redirects that
-// request to the subtree root (adding the trailing slash). This behavior can
-// be overridden with a separate registration for the path without
-// the trailing slash. For example, registering "/images/" causes ServeMux
-// to redirect a request for "/images" to "/images/", unless "/images" has
-// been registered separately.
-//
-// ServeMux also takes care of sanitizing the URL request path and
-// redirecting any request containing . or .. elements or repeated slashes
-// to an equivalent, cleaner URL.
-type ServeMux struct {
-	mu sync.RWMutex
-	m  map[string]muxEntry
-	es []muxEntry // slice of entries sorted from longest to shortest.
-}
-
-type muxEntry struct {
-	r       Responder
-	pattern string
-}
-
-// cleanPath returns the canonical path for p, eliminating . and .. elements.
-func cleanPath(p string) string {
-	if p == "" {
-		return "/"
-	}
-	if p[0] != '/' {
-		p = "/" + p
-	}
-	np := path.Clean(p)
-	// path.Clean removes trailing slash except for root;
-	// put the trailing slash back if necessary.
-	if p[len(p)-1] == '/' && np != "/" {
-		// Fast path for common case of p being the string we want:
-		if len(p) == len(np)+1 && strings.HasPrefix(p, np) {
-			np = p
-		} else {
-			np += "/"
-		}
-	}
-	return np
-}
-
-// Find a handler on a handler map given a path string.
-// Most-specific (longest) pattern wins.
-func (mux *ServeMux) match(path string) Responder {
-	// Check for exact match first.
-	v, ok := mux.m[path]
-	if ok {
-		return v.r
-	}
-
-	// Check for longest valid match.  mux.es contains all patterns
-	// that end in / sorted from longest to shortest.
-	for _, e := range mux.es {
-		if strings.HasPrefix(path, e.pattern) {
-			return e.r
-		}
-	}
-	return nil
-}
-
-// redirectToPathSlash determines if the given path needs appending "/" to it.
-// This occurs when a handler for path + "/" was already registered, but
-// not for path itself. If the path needs appending to, it creates a new
-// URL, setting the path to u.Path + "/" and returning true to indicate so.
-func (mux *ServeMux) redirectToPathSlash(path string, u *url.URL) (*url.URL, bool) {
-	mux.mu.RLock()
-	shouldRedirect := mux.shouldRedirectRLocked(path)
-	mux.mu.RUnlock()
-	if !shouldRedirect {
-		return u, false
-	}
-	path = path + "/"
-	u = &url.URL{Path: path, RawQuery: u.RawQuery}
-	return u, true
-}
-
-// shouldRedirectRLocked reports whether the given path and host should be redirected to
-// path+"/". This should happen if a handler is registered for path+"/" but
-// not path -- see comments at ServeMux.
-func (mux *ServeMux) shouldRedirectRLocked(path string) bool {
-	if _, exist := mux.m[path]; exist {
-		return false
-	}
-
-	n := len(path)
-	if n == 0 {
-		return false
-	}
-	if _, exist := mux.m[path+"/"]; exist {
-		return path[n-1] != '/'
-	}
-
-	return false
-}
-
-// Respond dispatches the request to the responder whose
-// pattern most closely matches the request URL.
-func (mux *ServeMux) Respond(w *ResponseWriter, r *Request) {
-	path := cleanPath(r.URL.Path)
-
-	// If the given path is /tree and its handler is not registered,
-	// redirect for /tree/.
-	if u, ok := mux.redirectToPathSlash(path, r.URL); ok {
-		Redirect(w, u.String())
-		return
-	}
-
-	if path != r.URL.Path {
-		u := *r.URL
-		u.Path = path
-		Redirect(w, u.String())
-		return
-	}
-
-	mux.mu.RLock()
-	defer mux.mu.RUnlock()
-
-	resp := mux.match(path)
-	if resp == nil {
-		w.WriteStatus(StatusNotFound)
-		return
-	}
-	resp.Respond(w, r)
-}
-
-// Handle registers the responder for the given pattern.
-// If a responder already exists for pattern, Handle panics.
-func (mux *ServeMux) Handle(pattern string, responder Responder) {
-	mux.mu.Lock()
-	defer mux.mu.Unlock()
-
-	if pattern == "" {
-		panic("gemini: invalid pattern")
-	}
-	if responder == nil {
-		panic("gemini: nil responder")
-	}
-	if _, exist := mux.m[pattern]; exist {
-		panic("gemini: multiple registrations for " + pattern)
-	}
-
-	if mux.m == nil {
-		mux.m = make(map[string]muxEntry)
-	}
-	e := muxEntry{responder, pattern}
-	mux.m[pattern] = e
-	if pattern[len(pattern)-1] == '/' {
-		mux.es = appendSorted(mux.es, e)
-	}
-}
-
-func appendSorted(es []muxEntry, e muxEntry) []muxEntry {
-	n := len(es)
-	i := sort.Search(n, func(i int) bool {
-		return len(es[i].pattern) < len(e.pattern)
-	})
-	if i == n {
-		return append(es, e)
-	}
-	// we now know that i points at where we want to insert
-	es = append(es, muxEntry{}) // try to grow the slice in place, any entry works.
-	copy(es[i+1:], es[i:])      // move shorter entries down
-	es[i] = e
-	return es
-}
-
-// HandleFunc registers the responder function for the given pattern.
-func (mux *ServeMux) HandleFunc(pattern string, responder func(*ResponseWriter, *Request)) {
-	if responder == nil {
-		panic("gemini: nil responder")
-	}
-	mux.Handle(pattern, ResponderFunc(responder))
-}