Allow init to skip mounting /product and /product_services
mainline-core is still in the progress of defining interfaces between
/system, /product, /product_services. Before that was completely done,
just updating /system to GSI usually couldn't boot a device.
Therefore, this CL allows GSI to specify a config file, telling init
not to mount /product and /product_services. And fallback to
/system/product and /system/product_services in the GSI.
Bug: 120208657
Test: boots a device with /system/etc/init/config/skip_mount.cfg and
checks both /product and /product_services are not mounted.
Change-Id: Ibe2abad30b178a6e552fb21e4b30207fc3ef5523
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index c96c381..acefdf0 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -42,6 +42,7 @@
#include "uevent_listener.h"
#include "util.h"
+using android::base::ReadFileToString;
using android::base::Split;
using android::base::Timer;
using android::fs_mgr::AvbHandle;
@@ -73,6 +74,8 @@
bool CreateLogicalPartitions();
bool MountPartition(FstabEntry* fstab_entry);
bool MountPartitions();
+ bool TrySwitchSystemAsRoot();
+ bool TrySkipMountingPartitions();
bool IsDmLinearEnabled();
bool GetDmLinearMetadataDevice();
bool InitDmLinearBackingDevices(const android::fs_mgr::LpMetadata& metadata);
@@ -398,10 +401,10 @@
return true;
}
-bool FirstStageMount::MountPartitions() {
- // If system is in the fstab then we're not a system-as-root device, and in
- // this case, we mount system first then pivot to it. From that point on,
- // we are effectively identical to a system-as-root device.
+// If system is in the fstab then we're not a system-as-root device, and in
+// this case, we mount system first then pivot to it. From that point on,
+// we are effectively identical to a system-as-root device.
+bool FirstStageMount::TrySwitchSystemAsRoot() {
auto system_partition = std::find_if(fstab_.begin(), fstab_.end(), [](const auto& entry) {
return entry.mount_point == "/system";
});
@@ -416,6 +419,44 @@
fstab_.erase(system_partition);
}
+ return true;
+}
+
+// For GSI to skip mounting /product and /product_services, until there are
+// well-defined interfaces between them and /system. Otherwise, the GSI flashed
+// on /system might not be able to work with /product and /product_services.
+// When they're skipped here, /system/product and /system/product_services in
+// GSI will be used.
+bool FirstStageMount::TrySkipMountingPartitions() {
+ constexpr const char kSkipMountConfig[] = "/system/etc/init/config/skip_mount.cfg";
+
+ std::string skip_config;
+ if (!ReadFileToString(kSkipMountConfig, &skip_config)) {
+ return true;
+ }
+
+ for (const auto& skip_mount_point : Split(skip_config, "\n")) {
+ if (skip_mount_point.empty()) {
+ continue;
+ }
+ auto removing_entry =
+ std::find_if(fstab_.begin(), fstab_.end(), [&skip_mount_point](const auto& entry) {
+ return entry.mount_point == skip_mount_point;
+ });
+ if (removing_entry != fstab_.end()) {
+ fstab_.erase(removing_entry);
+ LOG(INFO) << "Skip mounting partition: " << skip_mount_point;
+ }
+ }
+
+ return true;
+}
+
+bool FirstStageMount::MountPartitions() {
+ if (!TrySwitchSystemAsRoot()) return false;
+
+ if (!TrySkipMountingPartitions()) return false;
+
for (auto& fstab_entry : fstab_) {
if (!MountPartition(&fstab_entry) && !fstab_entry.fs_mgr_flags.no_fail) {
return false;