Make Linux ACL support optional, as it requires CGo and makes the binary less portable

1 files changed, 35 insertions, 0 deletions

diff --git a/internal/io/fs/permissions/permission_linuxacl.go b/internal/io/fs/permissions/permission_linuxacl.go
new file mode 100644
index 0000000..7d2d7ca
--- /dev/null
+++ b/internal/io/fs/permissions/permission_linuxacl.go
@@ -0,0 +1,35 @@
+// +build linuxacl
+
+package permissions
+
+/*
+#include "permission_linuxacl.h"
+#cgo LDFLAGS: -L. -lacl
+*/
+import "C"
+
+import (
+	"errors"
+	"unsafe"
+)
+
+// ToRead checks whether user has Linux file system permissions to read a given file.
+func ToRead(user, filePath string) (bool, error) {
+	cUser := C.CString(user)
+	cFilePath := C.CString(filePath)
+
+	defer C.free(unsafe.Pointer(cUser))
+	defer C.free(unsafe.Pointer(cFilePath))
+
+	cOk, err := C.permission_to_read(cUser, cFilePath)
+	if cOk == 1 {
+		return true, nil
+	}
+
+	if err != nil {
+		// err contains errno message
+		return false, err
+	}
+
+	return false, errors.New("User without permission to read file")
+}