From b49cb5eceaf426644da85ff9ab250d9c9aa7c510 Mon Sep 17 00:00:00 2001 From: Ryan Mitchell Date: Wed, 10 Feb 2021 11:27:29 -0800 Subject: [PATCH] Always delete old idmap in createIdmap If the target package updates its policies, and the overlay fails to successfully overlay any resources, the overlay should no longer work anymore. By deleting the old idmap file at the beginning of Idmap2Service::createIdmap, the overlay state will change to STATE_NO_IDMAP if the new idmap cannot be successfully generated. Bug: 173032050 Test: manual Change-Id: I1915e65feeb801d8602c12cc7df0f90da4c9b5c5 --- cmds/idmap2/idmap2d/Idmap2Service.cpp | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/cmds/idmap2/idmap2d/Idmap2Service.cpp b/cmds/idmap2/idmap2d/Idmap2Service.cpp index 312f4acbda9f1..05336baf9217f 100644 --- a/cmds/idmap2/idmap2d/Idmap2Service.cpp +++ b/cmds/idmap2/idmap2d/Idmap2Service.cpp @@ -161,6 +161,12 @@ Status Idmap2Service::createIdmap(const std::string& target_path, const std::str idmap_path.c_str(), uid)); } + // idmap files are mapped with mmap in libandroidfw. Deleting and recreating the idmap guarantees + // that existing memory maps will continue to be valid and unaffected. The file must be deleted + // before attempting to create the idmap, so that if idmap creation fails, the overlay will no + // longer be usable. + unlink(idmap_path.c_str()); + const auto target = GetTargetContainer(target_path); if (!target) { return error("failed to load target '%s'" + target_path); @@ -177,10 +183,6 @@ Status Idmap2Service::createIdmap(const std::string& target_path, const std::str return error(idmap.GetErrorMessage()); } - // idmap files are mapped with mmap in libandroidfw. Deleting and recreating the idmap guarantees - // that existing memory maps will continue to be valid and unaffected. - unlink(idmap_path.c_str()); - umask(kIdmapFilePermissionMask); std::ofstream fout(idmap_path); if (fout.fail()) {