osxkeychain: use go build constraint

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

osxkeychain/osxkeychain.go

@@ -0,0 +1,189 @@
+//go:build darwin && cgo
+
+package osxkeychain
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Security -framework Foundation
+
+#include "osxkeychain.h"
+#include <stdlib.h>
+*/
+import "C"
+
+import (
+	"errors"
+	"strconv"
+	"unsafe"
+
+	"github.com/docker/docker-credential-helpers/credentials"
+	"github.com/docker/docker-credential-helpers/registryurl"
+)
+
+// errCredentialsNotFound is the specific error message returned by OS X
+// when the credentials are not in the keychain.
+const errCredentialsNotFound = "The specified item could not be found in the keychain."
+
+// errCredentialsNotFound is the specific error message returned by OS X
+// when environment does not allow showing dialog to unlock keychain.
+const errInteractionNotAllowed = "User interaction is not allowed."
+
+// ErrInteractionNotAllowed is returned if keychain password prompt can not be shown.
+var ErrInteractionNotAllowed = errors.New(`keychain cannot be accessed because the current session does not allow user interaction. The keychain may be locked; unlock it by running "security -v unlock-keychain ~/Library/Keychains/login.keychain-db" and try again`)
+
+// Osxkeychain handles secrets using the OS X Keychain as store.
+type Osxkeychain struct{}
+
+// Add adds new credentials to the keychain.
+func (h Osxkeychain) Add(creds *credentials.Credentials) error {
+	_ = h.Delete(creds.ServerURL) // ignore errors as existing credential may not exist.
+
+	s, err := splitServer(creds.ServerURL)
+	if err != nil {
+		return err
+	}
+	defer freeServer(s)
+
+	label := C.CString(credentials.CredsLabel)
+	defer C.free(unsafe.Pointer(label))
+	username := C.CString(creds.Username)
+	defer C.free(unsafe.Pointer(username))
+	secret := C.CString(creds.Secret)
+	defer C.free(unsafe.Pointer(secret))
+
+	errMsg := C.keychain_add(s, label, username, secret)
+	if errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		return errors.New(C.GoString(errMsg))
+	}
+
+	return nil
+}
+
+// Delete removes credentials from the keychain.
+func (h Osxkeychain) Delete(serverURL string) error {
+	s, err := splitServer(serverURL)
+	if err != nil {
+		return err
+	}
+	defer freeServer(s)
+
+	if errMsg := C.keychain_delete(s); errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		switch goMsg := C.GoString(errMsg); goMsg {
+		case errCredentialsNotFound:
+			return credentials.NewErrCredentialsNotFound()
+		case errInteractionNotAllowed:
+			return ErrInteractionNotAllowed
+		default:
+			return errors.New(goMsg)
+		}
+	}
+
+	return nil
+}
+
+// Get returns the username and secret to use for a given registry server URL.
+func (h Osxkeychain) Get(serverURL string) (string, string, error) {
+	s, err := splitServer(serverURL)
+	if err != nil {
+		return "", "", err
+	}
+	defer freeServer(s)
+
+	var usernameLen C.uint
+	var username *C.char
+	var secretLen C.uint
+	var secret *C.char
+	defer C.free(unsafe.Pointer(username))
+	defer C.free(unsafe.Pointer(secret))
+
+	errMsg := C.keychain_get(s, &usernameLen, &username, &secretLen, &secret)
+	if errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		switch goMsg := C.GoString(errMsg); goMsg {
+		case errCredentialsNotFound:
+			return "", "", credentials.NewErrCredentialsNotFound()
+		case errInteractionNotAllowed:
+			return "", "", ErrInteractionNotAllowed
+		default:
+			return "", "", errors.New(goMsg)
+		}
+	}
+
+	user := C.GoStringN(username, C.int(usernameLen))
+	pass := C.GoStringN(secret, C.int(secretLen))
+	return user, pass, nil
+}
+
+// List returns the stored URLs and corresponding usernames.
+func (h Osxkeychain) List() (map[string]string, error) {
+	credsLabelC := C.CString(credentials.CredsLabel)
+	defer C.free(unsafe.Pointer(credsLabelC))
+
+	var pathsC **C.char
+	defer C.free(unsafe.Pointer(pathsC))
+	var acctsC **C.char
+	defer C.free(unsafe.Pointer(acctsC))
+	var listLenC C.uint
+	errMsg := C.keychain_list(credsLabelC, &pathsC, &acctsC, &listLenC)
+	defer C.freeListData(&pathsC, listLenC)
+	defer C.freeListData(&acctsC, listLenC)
+	if errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		switch goMsg := C.GoString(errMsg); goMsg {
+		case errCredentialsNotFound:
+			return make(map[string]string), nil
+		case errInteractionNotAllowed:
+			return nil, ErrInteractionNotAllowed
+		default:
+			return nil, errors.New(goMsg)
+		}
+	}
+
+	var listLen int
+	listLen = int(listLenC)
+	pathTmp := (*[1 << 30]*C.char)(unsafe.Pointer(pathsC))[:listLen:listLen]
+	acctTmp := (*[1 << 30]*C.char)(unsafe.Pointer(acctsC))[:listLen:listLen]
+	// taking the array of c strings into go while ignoring all the stuff irrelevant to credentials-helper
+	resp := make(map[string]string)
+	for i := 0; i < listLen; i++ {
+		if C.GoString(pathTmp[i]) == "0" {
+			continue
+		}
+		resp[C.GoString(pathTmp[i])] = C.GoString(acctTmp[i])
+	}
+	return resp, nil
+}
+
+func splitServer(serverURL string) (*C.struct_Server, error) {
+	u, err := registryurl.Parse(serverURL)
+	if err != nil {
+		return nil, err
+	}
+
+	proto := C.kSecProtocolTypeHTTPS
+	if u.Scheme == "http" {
+		proto = C.kSecProtocolTypeHTTP
+	}
+	var port int
+	p := u.Port()
+	if p != "" {
+		port, err = strconv.Atoi(p)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &C.struct_Server{
+		proto: C.SecProtocolType(proto),
+		host:  C.CString(u.Hostname()),
+		port:  C.uint(port),
+		path:  C.CString(u.Path),
+	}, nil
+}
+
+func freeServer(s *C.struct_Server) {
+	C.free(unsafe.Pointer(s.host))
+	C.free(unsafe.Pointer(s.path))
+}