fs_mgr: correct support for ro.build.system_root_image
Failed to convert fstab entries from "/" to "/system" when setting
up directory tree. Introduce an internal fs_mgr_mount_point to
simplify conversion.
Test: manual
Bug: 109821005
Change-Id: Iadc1e967b92702cf01b6522f8f13b2cf3685f2af
diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index fb57715..531610e 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -141,14 +141,13 @@
constexpr char upperdir_option[] = "upperdir=";
// default options for mount_point, returns empty string for none available.
-std::string fs_mgr_get_overlayfs_options(const char* mount_point) {
- auto fsrec_mount_point = std::string(mount_point);
- auto candidate = fs_mgr_get_overlayfs_candidate(fsrec_mount_point);
+std::string fs_mgr_get_overlayfs_options(const std::string& mount_point) {
+ auto candidate = fs_mgr_get_overlayfs_candidate(mount_point);
if (candidate.empty()) return "";
- auto context = fs_mgr_get_context(fsrec_mount_point);
+ auto context = fs_mgr_get_context(mount_point);
if (!context.empty()) context = ",rootcontext="s + context;
- return "override_creds=off,"s + lowerdir_option + fsrec_mount_point + "," + upperdir_option +
+ return "override_creds=off,"s + lowerdir_option + mount_point + "," + upperdir_option +
candidate + upper_name + ",workdir=" + candidate + work_name + context;
}
@@ -167,10 +166,11 @@
return true;
}
-std::string fs_mgr_get_overlayfs_options(const fstab* fstab, const char* mount_point) {
- if (fs_mgr_system_root_image(fstab) && ("/"s == mount_point)) mount_point = "/system";
-
- return fs_mgr_get_overlayfs_options(mount_point);
+const char* fs_mgr_mount_point(const fstab* fstab, const char* mount_point) {
+ if (!mount_point) return mount_point;
+ if ("/"s != mount_point) return mount_point;
+ if (!fs_mgr_system_root_image(fstab)) return mount_point;
+ return "/system";
}
// return true if system supports overlayfs
@@ -196,7 +196,7 @@
if (!fsrec) return false;
auto fsrec_mount_point = fsrec->mount_point;
- if (!fsrec_mount_point) return false;
+ if (!fsrec_mount_point || !fsrec_mount_point[0]) return false;
if (!fsrec->blk_device) return false;
if (!fsrec->fs_type) return false;
@@ -309,15 +309,12 @@
return ret;
}
-bool fs_mgr_overlayfs_mount(const fstab* fstab, const fstab_rec* fsrec) {
- if (!fs_mgr_wants_overlayfs(fsrec)) return false;
- auto fsrec_mount_point = fsrec->mount_point;
- if (!fsrec_mount_point || !fsrec_mount_point[0]) return false;
- auto options = fs_mgr_get_overlayfs_options(fstab, fsrec_mount_point);
+bool fs_mgr_overlayfs_mount(const std::string& mount_point) {
+ auto options = fs_mgr_get_overlayfs_options(mount_point);
if (options.empty()) return false;
// hijack __mount() report format to help triage
- auto report = "__mount(source=overlay,target="s + fsrec_mount_point + ",type=overlay";
+ auto report = "__mount(source=overlay,target="s + mount_point + ",type=overlay";
const auto opt_list = android::base::Split(options, ",");
for (const auto opt : opt_list) {
if (android::base::StartsWith(opt, upperdir_option)) {
@@ -327,7 +324,7 @@
}
report = report + ")=";
- auto ret = mount("overlay", fsrec_mount_point, "overlay", MS_RDONLY | MS_RELATIME,
+ auto ret = mount("overlay", mount_point.c_str(), "overlay", MS_RDONLY | MS_RELATIME,
options.c_str());
if (ret) {
PERROR << report << ret;
@@ -338,8 +335,7 @@
}
}
-bool fs_mgr_overlayfs_already_mounted(const char* mount_point) {
- if (!mount_point) return false;
+bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point) {
std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)> fstab(
fs_mgr_read_fstab("/proc/mounts"), fs_mgr_free_fstab);
if (!fstab) return false;
@@ -351,7 +347,7 @@
if (("overlay"s != fs_type) && ("overlayfs"s != fs_type)) continue;
auto fsrec_mount_point = fsrec->mount_point;
if (!fsrec_mount_point) continue;
- if (strcmp(fsrec_mount_point, mount_point)) continue;
+ if (mount_point != fsrec_mount_point) continue;
const auto fs_options = fsrec->fs_options;
if (!fs_options) continue;
const auto options = android::base::Split(fs_options, ",");
@@ -377,11 +373,10 @@
for (auto i = 0; i < fstab->num_entries; i++) {
const auto fsrec = &fstab->recs[i];
- auto fsrec_mount_point = fsrec->mount_point;
- if (!fsrec_mount_point) continue;
- if (fs_mgr_overlayfs_already_mounted(fsrec_mount_point)) continue;
-
- if (fs_mgr_overlayfs_mount(fstab.get(), fsrec)) ret = true;
+ if (!fs_mgr_wants_overlayfs(fsrec)) continue;
+ std::string mount_point(fs_mgr_mount_point(fstab.get(), fsrec->mount_point));
+ if (fs_mgr_overlayfs_already_mounted(mount_point)) continue;
+ if (fs_mgr_overlayfs_mount(mount_point)) ret = true;
}
return ret;
}
@@ -405,11 +400,12 @@
std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),
fs_mgr_free_fstab);
std::vector<std::string> mounts;
+ mount_point = fs_mgr_mount_point(fstab.get(), mount_point);
if (fstab) {
if (!fs_mgr_get_entry_for_mount_point(fstab.get(), kOverlayMountPoint)) return ret;
for (auto i = 0; i < fstab->num_entries; i++) {
const auto fsrec = &fstab->recs[i];
- auto fsrec_mount_point = fsrec->mount_point;
+ auto fsrec_mount_point = fs_mgr_mount_point(fstab.get(), fsrec->mount_point);
if (!fsrec_mount_point) continue;
if (mount_point && strcmp(fsrec_mount_point, mount_point)) continue;
if (!fs_mgr_wants_overlayfs(fsrec)) continue;
@@ -418,9 +414,6 @@
if (mounts.empty()) return ret;
}
- if (mount_point && ("/"s == mount_point) && fs_mgr_system_root_image(fstab.get())) {
- mount_point = "/system";
- }
auto overlay = kOverlayMountPoint + "/overlay/";
auto save_errno = errno;
if (!mkdir(overlay.c_str(), 0755)) {
@@ -443,11 +436,10 @@
// If something is altered, set *change.
bool fs_mgr_overlayfs_teardown(const char* mount_point, bool* change) {
if (change) *change = false;
- if (mount_point && ("/"s == mount_point)) {
- std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)> fstab(
- fs_mgr_read_fstab_default(), fs_mgr_free_fstab);
- if (fs_mgr_system_root_image(fstab.get())) mount_point = "/system";
- }
+ mount_point = fs_mgr_mount_point(std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)>(
+ fs_mgr_read_fstab_default(), fs_mgr_free_fstab)
+ .get(),
+ mount_point);
auto ret = true;
const auto overlay = kOverlayMountPoint + "/overlay";
const auto oldpath = overlay + (mount_point ?: "");