Fix race condition in Portage symlink creation.

diff --git a/pym/portage/util/movefile.py b/pym/portage/util/movefile.py
index 298d1518691cb6eb28b59fbe3bb0efdbe06707ca..f8cc695fb6d6b11a5c2b4663ad684b31ed6b5ba0 100644 (file)
--- a/pym/portage/util/movefile.py
+++ b/pym/portage/util/movefile.py
@@ -80,10 +80,18 @@ def movefile(src, dest, newmtime=None, sstat=None, mysettings=None,
                                        target=target[len(mysettings["D"]):]
                        if destexists and not stat.S_ISDIR(dstat[stat.ST_MODE]):
                                os.unlink(dest)
-                       if selinux_enabled:
-                               selinux.symlink(target, dest, src)
-                       else:
-                               os.symlink(target,dest)
+                       try:
+                               if selinux_enabled:
+                                       selinux.symlink(target, dest, src)
+                               else:
+                                       os.symlink(target, dest)
+                       except OSError as e:
+                               # Some programs will create symlinks automatically, so we have
+                               # to tolerate these links being recreated during the merge
+                               # process. In any case, if the link is pointing at the right
+                               # place, we're in good shape.
+                               if e.errno != errno.ENOENT or target != os.readlink(dest):
+                                       raise
                        lchown(dest,sstat[stat.ST_UID],sstat[stat.ST_GID])
                        # utime() only works on the target of a symlink, so it's not
                        # possible to perserve mtime on symlinks.