ueventd: fix subsystem list logic issues

1) Check subsystems list before doing usb subsystem logic.  This allows
   developers to handle usb* subsystems in ueventd.rc files.
2) Fix a bug where each subsystem_ instance is not reinitialized, but
   rather only the name_ member was set.

Test: boot bullhead
Test: check that multiple uevent_devname subsystems work when
      specified in ueventd.rc
Change-Id: Ifcac04763afcaf72a3b14ef5f3a6cb89981b51a1

3 files changed, 16 insertions, 17 deletions

diff --git a/init/devices.cpp b/init/devices.cpp
index d59f53c74..af6b50acb 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -386,26 +386,24 @@ void DeviceHandler::HandleDeviceEvent(const Uevent& uevent) {
         if (StartsWith(uevent.path, "/devices")) {
             links = GetBlockDeviceSymlinks(uevent);
         }
-    } else if (StartsWith(uevent.subsystem, "usb")) {
-        if (uevent.subsystem == "usb") {
-            if (!uevent.device_name.empty()) {
-                devpath = "/dev/" + uevent.device_name;
-            } else {
-                // This imitates the file system that would be created
-                // if we were using devfs instead.
-                // Minors are broken up into groups of 128, starting at "001"
-                int bus_id = uevent.minor / 128 + 1;
-                int device_id = uevent.minor % 128 + 1;
-                devpath = StringPrintf("/dev/bus/usb/%03d/%03d", bus_id, device_id);
-            }
-        } else {
-            // ignore other USB events
-            return;
-        }
     } else if (const auto subsystem =
                    std::find(subsystems_.cbegin(), subsystems_.cend(), uevent.subsystem);
                subsystem != subsystems_.cend()) {
         devpath = subsystem->ParseDevPath(uevent);
+    } else if (uevent.subsystem == "usb") {
+        if (!uevent.device_name.empty()) {
+            devpath = "/dev/" + uevent.device_name;
+        } else {
+            // This imitates the file system that would be created
+            // if we were using devfs instead.
+            // Minors are broken up into groups of 128, starting at "001"
+            int bus_id = uevent.minor / 128 + 1;
+            int device_id = uevent.minor % 128 + 1;
+            devpath = StringPrintf("/dev/bus/usb/%03d/%03d", bus_id, device_id);
+        }
+    } else if (StartsWith(uevent.subsystem, "usb")) {
+        // ignore other USB events
+        return;
     } else {
         devpath = "/dev/" + Basename(uevent.path);
     }
diff --git a/init/devices.h b/init/devices.h
index dd44337dc..1f8f1e8a9 100644
--- a/init/devices.h
+++ b/init/devices.h
@@ -72,6 +72,7 @@ class Subsystem {
     friend class SubsystemParser;
 
     Subsystem() {}
+    Subsystem(std::string name) : name_(std::move(name)) {}
 
     // Returns the full path for a uevent of a device that is a member of this subsystem,
     // according to the rules parsed from ueventd.rc
diff --git a/init/ueventd_parser.cpp b/init/ueventd_parser.cpp
index e831b8b63..cd7adb433 100644
--- a/init/ueventd_parser.cpp
+++ b/init/ueventd_parser.cpp
@@ -82,7 +82,7 @@ Result<Success> SubsystemParser::ParseSection(std::vector<std::string>&& args,
         return Error() << "ignoring duplicate subsystem entry";
     }
 
-    subsystem_.name_ = args[1];
+    subsystem_ = Subsystem(std::move(args[1]));
 
     return Success();
 }