v2api: add Darwin xattr support

1 files changed, 106 insertions, 0 deletions

diff --git a/internal/fusefrontend/node_xattr_darwin.go b/internal/fusefrontend/node_xattr_darwin.go
index e69de29..82c0dff 100644
--- a/internal/fusefrontend/node_xattr_darwin.go
+++ b/internal/fusefrontend/node_xattr_darwin.go
@@ -0,0 +1,106 @@
+package fusefrontend
+
+import (
+	"syscall"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/hanwen/go-fuse/v2/fs"
+
+	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
+)
+
+// On Darwin we have to unset XATTR_NOSECURITY 0x0008
+func filterXattrSetFlags(flags int) int {
+	// See https://opensource.apple.com/source/xnu/xnu-1504.15.3/bsd/sys/xattr.h.auto.html
+	const XATTR_NOSECURITY = 0x0008
+
+	return flags &^ XATTR_NOSECURITY
+}
+
+func (n *Node) getXAttr(cAttr string) (out []byte, errno syscall.Errno) {
+	dirfd, cName, errno := n.prepareAtSyscall("")
+	if errno != 0 {
+		return
+	}
+	defer syscall.Close(dirfd)
+
+	// O_NONBLOCK to not block on FIFOs.
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+	defer syscall.Close(fd)
+
+	cData, err := syscallcompat.Fgetxattr(fd, cAttr)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+
+	return cData, 0
+}
+
+func (n *Node) setXAttr(cAttr string, cData []byte, flags uint32) (errno syscall.Errno) {
+	dirfd, cName, errno := n.prepareAtSyscall("")
+	if errno != 0 {
+		return
+	}
+	defer syscall.Close(dirfd)
+
+	// O_NONBLOCK to not block on FIFOs.
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_WRONLY|syscall.O_NONBLOCK, 0)
+	// Directories cannot be opened read-write. Retry.
+	if err == syscall.EISDIR {
+		fd, err = syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK, 0)
+	}
+	if err != nil {
+		fs.ToErrno(err)
+	}
+	defer syscall.Close(fd)
+
+	err = unix.Fsetxattr(fd, cAttr, cData, int(flags))
+	return fs.ToErrno(err)
+}
+
+func (n *Node) removeXAttr(cAttr string) (errno syscall.Errno) {
+	dirfd, cName, errno := n.prepareAtSyscall("")
+	if errno != 0 {
+		return
+	}
+	defer syscall.Close(dirfd)
+
+	// O_NONBLOCK to not block on FIFOs.
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_WRONLY|syscall.O_NONBLOCK, 0)
+	// Directories cannot be opened read-write. Retry.
+	if err == syscall.EISDIR {
+		fd, err = syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK, 0)
+	}
+	if err != nil {
+		return fs.ToErrno(err)
+	}
+	defer syscall.Close(fd)
+
+	err = unix.Fremovexattr(fd, cAttr)
+	return fs.ToErrno(err)
+}
+
+func (n *Node) listXAttr() (out []string, errno syscall.Errno) {
+	dirfd, cName, errno := n.prepareAtSyscall("")
+	if errno != 0 {
+		return
+	}
+	defer syscall.Close(dirfd)
+
+	// O_NONBLOCK to not block on FIFOs.
+	fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+	defer syscall.Close(fd)
+
+	cNames, err := syscallcompat.Flistxattr(fd)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+	return cNames, 0
+}