Merge changes I819eb60a,I48a52aa0,Iab04742c into main

* changes:
  init: Reorder GetBlockDeviceSymlinks() so FindDmDevice() is first
  init: Add partition_uuid to Uevent
  fs_mgr: Add getter for androidboot.boot_part_uuid

fs_mgr/libfstab/fstab.cpp

@@ -950,6 +950,22 @@ std::set<std::string> GetBootDevices() {
     return ExtraBootDevices(fstab);
 }
 
+std::string GetBootPartUuid() {
+    std::string boot_part_uuid;
+
+    if (GetBootconfig("androidboot.boot_part_uuid", &boot_part_uuid)) {
+        return boot_part_uuid;
+    }
+
+    ImportKernelCmdline([&](std::string key, std::string value) {
+        if (key == "androidboot.boot_part_uuid") {
+            boot_part_uuid = value;
+        }
+    });
+
+    return boot_part_uuid;
+}
+
 std::string GetVerityDeviceName(const FstabEntry& entry) {
     std::string base_device;
     if (entry.mount_point == "/") {

fs_mgr/libfstab/include/fstab/fstab.h

@@ -126,6 +126,16 @@ void TransformFstabForDsu(Fstab* fstab, const std::string& dsu_slot,
 
 std::set<std::string> GetBootDevices();
 
+// Get the Partition UUID the kernel loaded from if the bootloader passed it.
+//
+// If the kernel's Partition UUID is provided then we can use this to help
+// identify which block device contains the filesystems we care about.
+//
+// NOTE: Nothing secures a UUID other than the convention that two disks
+// aren't supposed to both have the same UUID. We still need other mechanisms
+// to ensure we've got the right disk.
+std::string GetBootPartUuid();
+
 // Return the name of the dm-verity device for the given fstab entry. This does
 // not check whether the device is valid or exists; it merely returns the
 // expected name.

init/devices.cpp

@@ -376,7 +376,13 @@ std::vector<std::string> DeviceHandler::GetBlockDeviceSymlinks(const Uevent& uev
     std::string partition;
     std::string uuid;
 
-    if (FindPlatformDevice(uevent.path, &device)) {
+    if (FindDmDevice(uevent, &partition, &uuid)) {
+        std::vector<std::string> symlinks = {"/dev/block/mapper/" + partition};
+        if (!uuid.empty()) {
+            symlinks.emplace_back("/dev/block/mapper/by-uuid/" + uuid);
+        }
+        return symlinks;
+    } else if (FindPlatformDevice(uevent.path, &device)) {
         // Skip /devices/platform or /devices/ if present
         static constexpr std::string_view devices_platform_prefix = "/devices/platform/";
         static constexpr std::string_view devices_prefix = "/devices/";
@@ -392,12 +398,6 @@ std::vector<std::string> DeviceHandler::GetBlockDeviceSymlinks(const Uevent& uev
         type = "pci";
     } else if (FindVbdDevicePrefix(uevent.path, &device)) {
         type = "vbd";
-    } else if (FindDmDevice(uevent, &partition, &uuid)) {
-        std::vector<std::string> symlinks = {"/dev/block/mapper/" + partition};
-        if (!uuid.empty()) {
-            symlinks.emplace_back("/dev/block/mapper/by-uuid/" + uuid);
-        }
-        return symlinks;
     } else {
         return {};
     }

init/uevent.h

@@ -28,6 +28,7 @@ struct Uevent {
     std::string subsystem;
     std::string firmware;
     std::string partition_name;
+    std::string partition_uuid;
     std::string device_name;
     std::string modalias;
     int partition_num;

init/uevent_listener.cpp

@@ -66,6 +66,9 @@ static void ParseEvent(const char* msg, Uevent* uevent) {
         } else if (!strncmp(msg, "PARTNAME=", 9)) {
             msg += 9;
             uevent->partition_name = msg;
+        } else if (!strncmp(msg, "PARTUUID=", 9)) {
+            msg += 9;
+            uevent->partition_uuid = msg;
         } else if (!strncmp(msg, "DEVNAME=", 8)) {
             msg += 8;
             uevent->device_name = msg;
@@ -82,7 +85,7 @@ static void ParseEvent(const char* msg, Uevent* uevent) {
     if (LOG_UEVENTS) {
         LOG(INFO) << "event { '" << uevent->action << "', '" << uevent->path << "', '"
                   << uevent->subsystem << "', '" << uevent->firmware << "', " << uevent->major
-                  << ", " << uevent->minor << " }";
+                  << ", " << uevent->minor << ", " << uevent->partition_uuid << " }";
     }
 }