From 93134cfbc7c80dff0fe5b4b6b2352d44419dfadd Mon Sep 17 00:00:00 2001
From: Michal Hlavinka <mhlavink@redhat.com>
Date: Apr 02 2025 09:27:53 +0000
Subject: create temporary edit files at symlink target location


If file is a symlink, create new file at target location,
otherwise later rename() could fail, because symlink and target
can be at different directories which could mean different mount
points. This is especially true for containers and ostree

---

diff --git a/modules/files.c b/modules/files.c
index 109f4af..c3fef5b 100644
--- a/modules/files.c
+++ b/modules/files.c
@@ -360,6 +360,8 @@ editing_open(struct lu_module *module, const char *file_suffix,
 	     struct lu_error **error)
 {
 	struct editing *e;
+	struct stat st;
+	char *tmp;
 	char *backup_name;
 	int fd;
 
@@ -391,7 +393,23 @@ editing_open(struct lu_module *module, const char *file_suffix,
 		goto err_fscreate;
 	close(fd);
 
-	e->new_filename = g_strconcat(e->filename, "+", NULL);
+	/* If file is a symlink, create new file at target location,
+	 * otherwise later rename() could fail, because symlink and target
+	 * can be at different directories which could mean different mount
+	 * points. This is especially true for containers and ostree */
+	if (lstat(e->filename, &st) == 0 && S_ISLNK(st.st_mode)) {
+		tmp = realpath(e->filename, NULL);
+		if (tmp == NULL) {
+			lu_error_new(error, lu_error_generic,
+				     _("Error resolving `%s': %s"), e->filename,
+				     strerror(errno));
+			goto err_fscreate;
+		}
+		e->new_filename = g_strconcat(tmp, "+", NULL);
+		free(tmp);
+	} else {
+		e->new_filename = g_strconcat(e->filename, "+", NULL);
+	}
 	e->new_fd = open_and_copy_file(e->filename, e->new_filename, TRUE,
 			       	       error);
 	if (e->new_fd == -1)