init_gsi: Add support for optional alternate CAF audio policy

init/Android.bp

@@ -7,6 +7,7 @@ cc_binary {
         
         // SoC-specific quirks
         "quirks/soc/mtk_ril.cpp",
+        "quirks/soc/caf_audio.cpp",
         
         // Device-specific quirks
         "quirks/device/unihertz_keylayout.cpp",

init/init_gsi.cpp

@@ -59,6 +59,8 @@ int main(int argc, char **argv) {
         // Reset SPL / device model related props during late init
         // so that they are set before keystore / vold is started.
         handle_device_model_props();
+    } else if (argc >= 2 && strcmp(argv[1], "--post-fs-data") == 0) {
+        Quirks::RunPostData();
     } else {
         Quirks::Run();
     }

init/init_gsi.rc

@@ -4,5 +4,9 @@ on late-init
 on post-fs
     exec u:r:init_gsi:s0 root -- /system_ext/bin/init_gsi
 
+# When we call our post-fs-data actions, we would like persist properties to be available
+on load_persist_props_action
+    exec u:r:init_gsi:s0 root -- /system_ext/bin/init_gsi --post-fs-data
+
 on property:persist.sys.gsi.hw.mainkeys=*
     setprop qemu.hw.mainkeys ${persist.sys.gsi.hw.mainkeys}

init/quirks.cpp

@@ -40,6 +40,16 @@ void Quirks::Run() {
     }
 }
 
+void Quirks::RunPostData() {
+    if (quirks == nullptr) return;
+    
+    for (DeviceQuirk* quirk : *quirks) {
+        if (quirk->ShouldRun()) {
+            quirk->RunPostData();
+        }
+    }
+}
+
 // Utility functions for use with quirks
 #define QUIRKS_TMP_BASE_PATH "/mnt/quirks"
 #define QUIRKS_TMP_FILES_PATH QUIRKS_TMP_BASE_PATH "/files"

init/quirks.h

@@ -29,7 +29,8 @@ class DeviceQuirk {
 public:
     DeviceQuirk();
     virtual bool ShouldRun() = 0;
-    virtual void Run() = 0;
+    virtual void Run() {}
+    virtual void RunPostData() {}
     virtual ~DeviceQuirk();
 };
 
@@ -39,6 +40,7 @@ public:
 namespace Quirks {
     void Add(DeviceQuirk* quirk);
     void Run();
+    void RunPostData();
 
     int OverrideWithBindMount(filesystem::path src, filesystem::path dst);
 

init/quirks/soc/caf_audio.cpp

@@ -0,0 +1,21 @@
+#include "../../quirks.h"
+#include <android-base/properties.h>
+#include <filesystem>
+
+using namespace std;
+
+class CafAudioQuirk : DeviceQuirk {
+public:
+    bool ShouldRun() {
+        return filesystem::exists("/vendor/etc/audio/audio_policy_configuration.xml");
+    }
+    
+    void RunPostData() {
+        if (android::base::GetBoolProperty("persist.sys.gsi.alternate_audio_policy", false)) {
+            Quirks::OverrideWithBindMount("/vendor/etc/audio/audio_policy_configuration.xml", "/vendor/etc/audio_policy_configuration.xml");
+            android::base::SetProperty("ctl.restart", "audioserver"); // Ensure our new policy is loaded into audioserver
+        }
+    }
+};
+
+LOAD_QUIRK(CafAudioQuirk);