ctlsock: add CtlSock API

ctlsock/ctlsock.go

@@ -2,25 +2,60 @@
 // gocryptfs control socket interface. This interface can be
 // activated by passing `-ctlsock /tmp/my.sock` to gocryptfs on the
 // command line.
+// See gocryptfs-xray for a usage example.
 package ctlsock
 
-// RequestStruct is sent by a client
-type RequestStruct struct {
-	EncryptPath string
-	DecryptPath string
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+	"time"
+)
+
+func (r *ResponseStruct) Error() string {
+	return fmt.Sprintf("errno %d: %s", r.ErrNo, r.ErrText)
 }
 
-// ResponseStruct is sent by the server in response to a request
-type ResponseStruct struct {
-	// Result is the resulting decrypted or encrypted path. Empty on error.
-	Result string
-	// ErrNo is the error number as defined in errno.h.
-	// 0 means success and -1 means that the error number is not known
-	// (look at ErrText in this case).
-	ErrNo int32
-	// ErrText is a detailed error message.
-	ErrText string
-	// WarnText contains warnings that may have been encountered while
-	// processing the message.
-	WarnText string
+// CtlSock encapsulates a control socket
+type CtlSock struct {
+	Conn net.Conn
+}
+
+// New opens the socket at `socketPath` and stores it in a `CtlSock` object.
+func New(socketPath string) (*CtlSock, error) {
+	conn, err := net.DialTimeout("unix", socketPath, 1*time.Second)
+	if err != nil {
+		return nil, err
+	}
+	return &CtlSock{Conn: conn}, nil
+}
+
+// Query sends a request to the control socket returns the response.
+func (c *CtlSock) Query(req *RequestStruct) (*ResponseStruct, error) {
+	c.Conn.SetDeadline(time.Now().Add(time.Second))
+	msg, err := json.Marshal(req)
+	if err != nil {
+		return nil, err
+	}
+	_, err = c.Conn.Write(msg)
+	if err != nil {
+		return nil, err
+	}
+	buf := make([]byte, 5000)
+	n, err := c.Conn.Read(buf)
+	if err != nil {
+		return nil, err
+	}
+	buf = buf[:n]
+	var resp ResponseStruct
+	json.Unmarshal(buf, &resp)
+	if resp.ErrNo != 0 {
+		return nil, &resp
+	}
+	return &resp, nil
+}
+
+// Close closes the socket
+func (c *CtlSock) Close() {
+	c.Conn.Close()
 }

ctlsock/json_abi.go

@@ -0,0 +1,26 @@
+package ctlsock
+
+// RequestStruct is sent by a client (encoded as JSON).
+// You cannot perform both encryption and decryption in the same request.
+type RequestStruct struct {
+	// EncryptPath is the path that should be encrypted.
+	EncryptPath string
+	// DecryptPath is the path that should be decrypted.
+	DecryptPath string
+}
+
+// ResponseStruct is sent by the server in response to a request
+// (encoded as JSON).
+type ResponseStruct struct {
+	// Result is the resulting decrypted or encrypted path. Empty on error.
+	Result string
+	// ErrNo is the error number as defined in errno.h.
+	// 0 means success and -1 means that the error number is not known
+	// (look at ErrText in this case).
+	ErrNo int32
+	// ErrText is a detailed error message.
+	ErrText string
+	// WarnText contains warnings that may have been encountered while
+	// processing the message.
+	WarnText string
+}