1 files changed, 99 insertions, 0 deletions
diff --git a/internal/acl/c.go b/internal/acl/c.go
new file mode 100644
index 00000000..89bc0469
--- /dev/null
+++ b/internal/acl/c.go
@@ -0,0 +1,99 @@
+package acl
+
+import (
+	"errors"
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+//#include <stdlib.h>
+//#include <sys/acl.h>
+//#include <acl/libacl.h>
+//#cgo linux LDFLAGS: -lacl
+import "C"
+
+type acl struct {
+	val   C.acl_t
+	freed bool
+}
+
+func aclGetFile(path string, t C.acl_type_t) (*acl, error) {
+	p := C.CString(path)
+	a, err := C.acl_get_file(p, t)
+	C.free(unsafe.Pointer(p))
+
+	if errors.Is(err, syscall.ENODATA) {
+		err = nil
+	}
+	return &acl{val: a, freed: false}, err
+}
+
+func (a *acl) setFile(path string, t C.acl_type_t) error {
+	if C.acl_valid(a.val) != 0 {
+		return fmt.Errorf("invalid acl")
+	}
+
+	p := C.CString(path)
+	_, err := C.acl_set_file(p, t, a.val)
+	C.free(unsafe.Pointer(p))
+	return err
+}
+
+func (a *acl) removeEntry(tt C.acl_tag_t, tq int) error {
+	var e C.acl_entry_t
+
+	// get first entry
+	if r, err := C.acl_get_entry(a.val, C.ACL_FIRST_ENTRY, &e); err != nil {
+		return err
+	} else if r == 0 {
+		// return on acl with no entries
+		return nil
+	}
+
+	for {
+		if r, err := C.acl_get_entry(a.val, C.ACL_NEXT_ENTRY, &e); err != nil {
+			return err
+		} else if r == 0 {
+			// return on drained acl
+			return nil
+		}
+
+		var (
+			q int
+			t C.acl_tag_t
+		)
+
+		// get current entry tag type
+		if _, err := C.acl_get_tag_type(e, &t); err != nil {
+			return err
+		}
+
+		// get current entry qualifier
+		if rq, err := C.acl_get_qualifier(e); err != nil {
+			// neither ACL_USER nor ACL_GROUP
+			if errors.Is(err, syscall.EINVAL) {
+				continue
+			}
+
+			return err
+		} else {
+			q = *(*int)(rq)
+			C.acl_free(rq)
+		}
+
+		// delete on match
+		if t == tt && q == tq {
+			_, err := C.acl_delete_entry(a.val, e)
+			return err
+		}
+	}
+}
+
+func (a *acl) free() {
+	if a.freed {
+		panic("acl already freed")
+	}
+	C.acl_free(unsafe.Pointer(a.val))
+	a.freed = true
+}