From b5ad9369fe07383d88ae9af3276eaf34723223d7 Mon Sep 17 00:00:00 2001
From: ed <s@ocv.me>
Date: Sat, 7 Sep 2024 19:17:32 +0000
Subject: [PATCH] confine xlink behavior behind its volflag

symlinks between volumes will only be created if xlink is
enabled, so such symlinks should be ignored if xlink is
disabled, as they might originate from other software

this prevents accidental rewriting of non-dedup symlinks
---
 copyparty/up2k.py | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index c4add624..b73e6732 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -3755,8 +3755,11 @@ class Up2k(object):
                     cur = None
                     try:
                         ptop = dbv.realpath
+                        xlink = bool(dbv.flags.get("xlink"))
                         cur, wark, _, _, _, _ = self._find_from_vpath(ptop, volpath)
-                        self._forget_file(ptop, volpath, cur, wark, True, st.st_size)
+                        self._forget_file(
+                            ptop, volpath, cur, wark, True, st.st_size, xlink
+                        )
                     finally:
                         if cur:
                             cur.connection.commit()
@@ -3980,13 +3983,15 @@ class Up2k(object):
             if c2 and c2 != c1:
                 self._copy_tags(c1, c2, w)
 
+            xlink = bool(svn.flags.get("xlink"))
+
             with self.reg_mutex:
                 has_dupes = self._forget_file(
-                    svn.realpath, srem, c1, w, is_xvol, fsize_ or fsize
+                    svn.realpath, srem, c1, w, is_xvol, fsize_ or fsize, xlink
                 )
 
             if not is_xvol:
-                has_dupes = self._relink(w, svn.realpath, srem, dabs)
+                has_dupes = self._relink(w, svn.realpath, srem, dabs, c1, xlink)
 
             curs.add(c1)
 
@@ -4129,6 +4134,7 @@ class Up2k(object):
         wark: Optional[str],
         drop_tags: bool,
         sz: int,
+        xlink: bool,
     ) -> bool:
         """
         mutex(main,reg) me
@@ -4140,7 +4146,7 @@ class Up2k(object):
         if wark and cur:
             self.log("found {} in db".format(wark))
             if drop_tags:
-                if self._relink(wark, ptop, vrem, ""):
+                if self._relink(wark, ptop, vrem, "", cur, xlink):
                     has_dupes = True
                     drop_tags = False
 
@@ -4172,7 +4178,15 @@ class Up2k(object):
 
         return has_dupes
 
-    def _relink(self, wark: str, sptop: str, srem: str, dabs: str) -> int:
+    def _relink(
+        self,
+        wark: str,
+        sptop: str,
+        srem: str,
+        dabs: str,
+        vcur: Optional["sqlite3.Cursor"],
+        xlink: bool,
+    ) -> int:
         """
         update symlinks from file at svn/srem to dabs (rename),
         or to first remaining full if no dabs (delete)
@@ -4188,6 +4202,8 @@ class Up2k(object):
             argv = (wark[:16], wark)
 
         for ptop, cur in self.cur.items():
+            if not xlink and cur and cur != vcur:
+                continue
             for rd, fn in cur.execute(q, argv):
                 if rd.startswith("//") or fn.startswith("//"):
                     rd, fn = s3dec(rd, fn)