Make zygotes aware of their supported ABIs.

Query system properties for the list of ABIs and pass
it as a command line argument to ZygoteInit.

Also add a new Zygote command that returns this list of
ABIs to peers.

Change-Id: I68034c6f63fa626911122579a011a0a25a8cda94
diff --git a/cmds/app_process/app_main.cpp b/cmds/app_process/app_main.cpp
index e0290c3..3e8d6a0 100644
--- a/cmds/app_process/app_main.cpp
+++ b/cmds/app_process/app_main.cpp
@@ -10,8 +10,9 @@
 #include <binder/IPCThreadState.h>
 #include <binder/ProcessState.h>
 #include <utils/Log.h>
-#include <cutils/process_name.h>
 #include <cutils/memory.h>
+#include <cutils/process_name.h>
+#include <cutils/properties.h>
 #include <cutils/trace.h>
 #include <android_runtime/AndroidRuntime.h>
 
@@ -135,6 +136,12 @@
     return (end - start);
 }
 
+#if defined(__LP64__)
+static const char ABI_LIST_PROPERTY[] = "ro.product.cpu.abilist64";
+#else
+static const char ABI_LIST_PROPERTY[] = "ro.product.cpu.abilist32";
+#endif
+
 int main(int argc, char* const argv[])
 {
     AppRuntime runtime(argv[0], computeArgBlockSize(argc, argv));
@@ -205,6 +212,17 @@
             args.add(String8("start-system-server"));
         }
 
+        char prop[PROP_VALUE_MAX];
+        if (property_get(ABI_LIST_PROPERTY, prop, NULL) == 0) {
+            LOG_ALWAYS_FATAL("app_process: Unable to deterimine ABI list from property %s.",
+                ABI_LIST_PROPERTY);
+            return 11;
+        }
+
+        String8 abiFlag("--abi-list=");
+        abiFlag.append(prop);
+        args.add(abiFlag);
+
         // In zygote mode, pass all remaining arguments to the zygote
         // main() method.
         for (; i < argc; ++i) {