add support custom tls config

Author: daqingshu

doc.go

@@ -68,6 +68,47 @@ Valid values for sslmode are:
 	  the server was signed by a trusted CA and the server host name
 	  matches the one in the certificate)
 
+For support ssl key in memory, we extend sslmode. For example:
+
+	import (
+		"crypto/tls"
+		"crypto/x509"
+		"io/ioutil"
+		"log"
+
+		"github.com/lib/pq"
+	)
+
+	func main() {
+		rootCertPool := x509.NewCertPool()
+		pem, err := ioutil.ReadFile("ca.crt")
+		if err != nil {
+			log.Fatal(err)
+		}
+		if ok := rootCertPool.AppendCertsFromPEM(pem); !ok {
+			log.Fatal("Failed to append PEM.")
+		}
+		clientCert := make([]tls.Certificate, 0, 1)
+		certs, err := tls.LoadX509KeyPair("client1.crt", "client1.key")
+		if err != nil {
+			log.Fatal(err)
+		}
+		clientCert = append(clientCert, certs)
+		err = pq.RegisterTLSConfig("custom", &tls.Config{
+			RootCAs:      rootCertPool,
+			Certificates: clientCert,
+			ServerName:   "pq.example.com",
+		})
+		if err != nil {
+			log.Fatal(err)
+		}
+		connStr := "host=pq.example.com port=5432 user=user1 dbname=pqgotest password=pqgotest sslmode=custom"
+		db, err := sql.Open("postgres", connStr)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
 See http://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING
 for more information about connection string parameters.
 

ssl.go

@@ -3,18 +3,74 @@ package pq
 import (
 	"crypto/tls"
 	"crypto/x509"
+	"fmt"
 	"io/ioutil"
 	"net"
 	"os"
 	"os/user"
 	"path/filepath"
+	"strings"
+	"sync"
 )
 
+// Registry for custom tls.Configs
+var (
+	tlsConfigLock     sync.RWMutex
+	tlsConfigRegistry map[string]*tls.Config
+)
+
+func RegisterTLSConfig(key string, config *tls.Config) error {
+	if _, isBool := readBool(key); isBool || strings.ToLower(key) == "require" || strings.ToLower(key) == "verify-ca" || strings.ToLower(key) == "verify-full" || strings.ToLower(key) == "disable" {
+		return fmt.Errorf("key '%s' is reserved", key)
+	}
+
+	tlsConfigLock.Lock()
+	if tlsConfigRegistry == nil {
+		tlsConfigRegistry = make(map[string]*tls.Config)
+	}
+
+	tlsConfigRegistry[key] = config
+	tlsConfigLock.Unlock()
+	return nil
+}
+
+// DeregisterTLSConfig removes the tls.Config associated with key.
+func DeregisterTLSConfig(key string) {
+	tlsConfigLock.Lock()
+	if tlsConfigRegistry != nil {
+		delete(tlsConfigRegistry, key)
+	}
+	tlsConfigLock.Unlock()
+}
+
+func getTLSConfigClone(key string) (config *tls.Config) {
+	tlsConfigLock.RLock()
+	if v, ok := tlsConfigRegistry[key]; ok {
+		config = v.Clone()
+	}
+	tlsConfigLock.RUnlock()
+	return
+}
+
+// Returns the bool value of the input.
+// The 2nd return value indicates if the input was a valid bool value
+func readBool(input string) (value bool, valid bool) {
+	switch input {
+	case "1", "true", "TRUE", "True":
+		return true, true
+	case "0", "false", "FALSE", "False":
+		return false, true
+	}
+
+	// Not a valid bool value
+	return
+}
+
 // ssl generates a function to upgrade a net.Conn based on the "sslmode" and
 // related settings. The function is nil when no upgrade should take place.
 func ssl(o values) (func(net.Conn) (net.Conn, error), error) {
 	verifyCaOnly := false
-	tlsConf := tls.Config{}
+	tlsConf := &tls.Config{}
 	switch mode := o["sslmode"]; mode {
 	// "require" is the default.
 	case "", "require":
@@ -47,14 +103,19 @@ func ssl(o values) (func(net.Conn) (net.Conn, error), error) {
 	case "disable":
 		return nil, nil
 	default:
-		return nil, fmterrorf(`unsupported sslmode %q; only "require" (default), "verify-full", "verify-ca", and "disable" supported`, mode)
+		{
+			tlsConf = getTLSConfigClone(mode)
+			if tlsConf == nil {
+				return nil, fmterrorf(`unsupported sslmode %q; only "require" (default), "verify-full", "verify-ca", and "disable" supported`, mode)
+			}
+		}
 	}
 
-	err := sslClientCertificates(&tlsConf, o)
+	err := sslClientCertificates(tlsConf, o)
 	if err != nil {
 		return nil, err
 	}
-	err = sslCertificateAuthority(&tlsConf, o)
+	err = sslCertificateAuthority(tlsConf, o)
 	if err != nil {
 		return nil, err
 	}
@@ -67,9 +128,9 @@ func ssl(o values) (func(net.Conn) (net.Conn, error), error) {
 	tlsConf.Renegotiation = tls.RenegotiateFreelyAsClient
 
 	return func(conn net.Conn) (net.Conn, error) {
-		client := tls.Client(conn, &tlsConf)
+		client := tls.Client(conn, tlsConf)
 		if verifyCaOnly {
-			err := sslVerifyCertificateAuthority(client, &tlsConf)
+			err := sslVerifyCertificateAuthority(client, tlsConf)
 			if err != nil {
 				return nil, err
 			}