Merge "fs_mgr: overlay check shared blocks for / if /system is not"
diff --git a/fs_mgr/libfs_avb/avb_ops.cpp b/fs_mgr/libfs_avb/avb_ops.cpp
index 6a3e2c0..c192bf5 100644
--- a/fs_mgr/libfs_avb/avb_ops.cpp
+++ b/fs_mgr/libfs_avb/avb_ops.cpp
@@ -36,6 +36,7 @@
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <libavb/libavb.h>
+#include <libdm/dm.h>
#include <utils/Compat.h>
#include "util.h"
@@ -104,6 +105,20 @@
return AVB_IO_RESULT_OK;
}
+// Converts a partition name (with ab_suffix) to the corresponding mount point.
+// e.g., "system_a" => "/system",
+// e.g., "vendor_a" => "/vendor",
+static std::string DeriveMountPoint(const std::string& partition_name) {
+ const std::string ab_suffix = fs_mgr_get_slot_suffix();
+ std::string mount_point(partition_name);
+ auto found = partition_name.rfind(ab_suffix);
+ if (found != std::string::npos) {
+ mount_point.erase(found); // converts system_a => system
+ }
+
+ return "/" + mount_point;
+}
+
FsManagerAvbOps::FsManagerAvbOps() {
// We only need to provide the implementation of read_from_partition()
// operation since that's all what is being used by the avb_slot_verify().
@@ -122,14 +137,53 @@
avb_ops_.user_data = this;
}
+// Given a partition name (with ab_suffix), e.g., system_a, returns the corresponding
+// dm-linear path for it. e.g., /dev/block/dm-0. If not found, returns an empty string.
+// This assumes that the prefix of the partition name and the mount point are the same.
+// e.g., partition vendor_a is mounted under /vendor, product_a is mounted under /product, etc.
+// This might not be true for some special fstab files, e.g., fstab.postinstall.
+// But it's good enough for the default fstab. Also note that the logical path is a
+// fallback solution when the physical path (/dev/block/by-name/<partition>) cannot be found.
+std::string FsManagerAvbOps::GetLogicalPath(const std::string& partition_name) {
+ if (fstab_.empty() && !ReadDefaultFstab(&fstab_)) {
+ return "";
+ }
+
+ const auto mount_point = DeriveMountPoint(partition_name);
+ if (mount_point.empty()) return "";
+
+ auto fstab_entry = GetEntryForMountPoint(&fstab_, mount_point);
+ if (!fstab_entry) return "";
+
+ std::string device_path;
+ if (fstab_entry->fs_mgr_flags.logical) {
+ dm::DeviceMapper& dm = dm::DeviceMapper::Instance();
+ if (!dm.GetDmDevicePathByName(fstab_entry->blk_device, &device_path)) {
+ LERROR << "Failed to resolve logical device path for: " << fstab_entry->blk_device;
+ return "";
+ }
+ return device_path;
+ }
+
+ return "";
+}
+
AvbIOResult FsManagerAvbOps::ReadFromPartition(const char* partition, int64_t offset,
size_t num_bytes, void* buffer,
size_t* out_num_read) {
- const std::string path = "/dev/block/by-name/"s + partition;
+ std::string path = "/dev/block/by-name/"s + partition;
// Ensures the device path (a symlink created by init) is ready to access.
if (!WaitForFile(path, 1s)) {
- return AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION;
+ LERROR << "Device path not found: " << path;
+ // Falls back to logical path if the physical path is not found.
+ // This mostly only works for emulator (no bootloader). Because in normal
+ // device, bootloader is unable to read logical partitions. So if libavb in
+ // the bootloader failed to read a physical partition, it will failed to boot
+ // the HLOS and we won't reach the code here.
+ path = GetLogicalPath(partition);
+ if (path.empty() || !WaitForFile(path, 1s)) return AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION;
+ LINFO << "Fallback to use logical device path: " << path;
}
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC)));
diff --git a/fs_mgr/libfs_avb/avb_ops.h b/fs_mgr/libfs_avb/avb_ops.h
index a849d94..b39812d 100644
--- a/fs_mgr/libfs_avb/avb_ops.h
+++ b/fs_mgr/libfs_avb/avb_ops.h
@@ -28,6 +28,7 @@
#include <vector>
#include <fs_avb/types.h>
+#include <fstab/fstab.h>
#include <libavb/libavb.h>
namespace android {
@@ -60,7 +61,9 @@
std::vector<VBMetaData>* out_vbmeta_images);
private:
+ std::string GetLogicalPath(const std::string& partition_name);
AvbOps avb_ops_;
+ Fstab fstab_;
};
} // namespace fs_mgr
