Read .rc files from bootstrap apexes

To start an early_hal service from a bootstrap vendor apex, init now
reads .rc files from bootstrap apexes as well.

In this change, perform_apex_config command is re-purposed to support
bootstrap mode. Now we have some similarity between two apexd calls:

- for bootstrap apexes (in the bootstrap mount namespace):

  exec_start apexd-bootstrap
  perform_apex_config --bootstrap

- for normal apexes (in the default mount namespace):

  restart apexd
  ...
  wait_for_prop apexd.status activated
  perform_apex_config

Note that some tasks in perform_apex_config are not needed in the
bootstrap.  For example, we don't need to create apexdata directories
for bootstrap apexes.

Bug: 290148081
Test: VendorApexHostTestCases
Change-Id: I8f683a4dcd7cd9a2466a4b1b417d84c025c37761

init/README.md

@@ -674,11 +674,12 @@ provides the `aidl_lazy_test_1` interface.
   _options_ include "barrier=1", "noauto\_da\_alloc", "discard", ... as
   a comma separated string, e.g. barrier=1,noauto\_da\_alloc
 
-`perform_apex_config`
+`perform_apex_config [--bootstrap]`
 > Performs tasks after APEXes are mounted. For example, creates data directories
   for the mounted APEXes, parses config file(s) from them, and updates linker
   configurations. Intended to be used only once when apexd notifies the mount
   event by setting `apexd.status` to ready.
+  Use --bootstrap when invoking in the bootstrap mount namespace.
 
 `restart [--only-if-running] <service>`
 > Stops and restarts a running service, does nothing if the service is currently

init/builtins.cpp

@@ -1292,10 +1292,21 @@ static Result<void> create_apex_data_dirs() {
 }
 
 static Result<void> do_perform_apex_config(const BuiltinArguments& args) {
-    auto create_dirs = create_apex_data_dirs();
-    if (!create_dirs.ok()) {
-        return create_dirs.error();
+    bool bootstrap = false;
+    if (args.size() == 2) {
+        if (args[1] != "--bootstrap") {
+            return Error() << "Unexpected argument: " << args[1];
+        }
+        bootstrap = true;
     }
+
+    if (!bootstrap) {
+        auto create_dirs = create_apex_data_dirs();
+        if (!create_dirs.ok()) {
+            return create_dirs.error();
+        }
+    }
+
     auto parse_configs = ParseApexConfigs(/*apex_name=*/"");
     if (!parse_configs.ok()) {
         return parse_configs.error();
@@ -1306,8 +1317,10 @@ static Result<void> do_perform_apex_config(const BuiltinArguments& args) {
         return update_linker_config.error();
     }
 
-    // Now start delayed services
-    ServiceList::GetInstance().MarkServicesUpdate();
+    if (!bootstrap) {
+        // Now start delayed services
+        ServiceList::GetInstance().MarkServicesUpdate();
+    }
     return {};
 }
 
@@ -1362,7 +1375,7 @@ const BuiltinFunctionMap& GetBuiltinFunctionMap() {
         // mount and umount are run in the same context as mount_all for symmetry.
         {"mount_all",               {0,     kMax, {false,  do_mount_all}}},
         {"mount",                   {3,     kMax, {false,  do_mount}}},
-        {"perform_apex_config",     {0,     0,    {false,  do_perform_apex_config}}},
+        {"perform_apex_config",     {0,     1,    {false,  do_perform_apex_config}}},
         {"umount",                  {1,     1,    {false,  do_umount}}},
         {"umount_all",              {0,     1,    {false,  do_umount_all}}},
         {"update_linker_config",    {0,     0,    {false,  do_update_linker_config}}},

rootdir/init.rc

@@ -74,9 +74,7 @@ on early-init
     # become available. Note that this is executed as exec_start to ensure that
     # the libraries are available to the processes started after this statement.
     exec_start apexd-bootstrap
-
-    # Generate linker config based on apex mounted in bootstrap namespace
-    update_linker_config
+    perform_apex_config --bootstrap
 
     # These must already exist by the time boringssl_self_test32 / boringssl_self_test64 run.
     mkdir /dev/boringssl 0755 root root