liblp: Support sdcards in PartitionOpener.
Before ImageManager was introduced, gsid avoided using PartitionOpener
when writing to external media. PartitionOpener couldn't interact with
non-boot devices, because it prepends /dev/block/by-name. We hacked
around this in both gsid and in first-stage init, which manually detects
the problem and prepends /dev/block instead.
After the ImageManager refactoring, sdcard support broke in gsid,
because it started relying on PartitionOpener. Let's fix this by allowing
/dev/block for mmcblk* names in PartitionOpener.
Bug: 139204329
Test: fiemap_image_test gtest
Change-Id: Ic1cbdbe0a18fc09522ee38cc62b35fd8193ce250
diff --git a/fs_mgr/liblp/partition_opener.cpp b/fs_mgr/liblp/partition_opener.cpp
index f1e8fc2..1d4db85 100644
--- a/fs_mgr/liblp/partition_opener.cpp
+++ b/fs_mgr/liblp/partition_opener.cpp
@@ -41,7 +41,21 @@
if (android::base::StartsWith(path, "/")) {
return path;
}
- return "/dev/block/by-name/" + path;
+
+ auto by_name = "/dev/block/by-name/" + path;
+ if (access(by_name.c_str(), F_OK) != 0) {
+ // If the by-name symlink doesn't exist, as a special case we allow
+ // certain devices to be used as partition names. This can happen if a
+ // Dynamic System Update is installed to an sdcard, which won't be in
+ // the boot device list.
+ //
+ // We whitelist because most devices in /dev/block are not valid for
+ // storing fiemaps.
+ if (android::base::StartsWith(path, "mmcblk")) {
+ return "/dev/block/" + path;
+ }
+ }
+ return by_name;
}
bool GetBlockDeviceInfo(const std::string& block_device, BlockDeviceInfo* device_info) {
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index 1a5ed28..dffd6af 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -602,19 +602,11 @@
return;
}
- // Find the name of the super partition for the GSI. It will either be
- // "userdata", or a block device such as an sdcard. There are no by-name
- // partitions other than userdata that we support installing GSIs to.
+ // Find the super name. PartitionOpener will ensure this translates to the
+ // correct block device path.
auto super = GetMetadataSuperBlockDevice(*metadata.get());
- std::string super_name = android::fs_mgr::GetBlockDevicePartitionName(*super);
- std::string super_path;
- if (super_name == "userdata") {
- super_path = "/dev/block/by-name/" + super_name;
- } else {
- super_path = "/dev/block/" + super_name;
- }
-
- if (!android::fs_mgr::CreateLogicalPartitions(*metadata.get(), super_path)) {
+ auto super_name = android::fs_mgr::GetBlockDevicePartitionName(*super);
+ if (!android::fs_mgr::CreateLogicalPartitions(*metadata.get(), super_name)) {
LOG(ERROR) << "GSI partition layout could not be instantiated";
return;
}