commit ee8e3dd67c910907115c7cef87be3d898d71a05d
author Tom Cherry <tomcherry@google.com> Wed Feb 21 15:01:22 2018 -0800
committer Tom Cherry <tomcherry@google.com> Wed Feb 21 15:10:17 2018 -0800
tree 022d9c97d9bdc95c34dbf0052b8dcf9ce394bc46
parent 44c7b6ad0ac277a8ed3ee2278f6c1ee23f130ab5

Remove non-trivial constructors/destructors from SystemProperties

With the goal of disallowing exit time destructors, SystemProperties's
non-trivial destructor needs to be removed.  This means replacing the
union hack with yet another hack as we don't want to allocate anything
despite relying on some polymorphism.

Bug: 73485611
Test: boot bullhead
Change-Id: I64223714c9b26c9724bfb8f3e2b0168e47b56bc8

libc/system_properties/system_properties.cpp

diff --git a/libc/system_properties/system_properties.cpp b/libc/system_properties/system_properties.cpp
index c610df2..7c48b8e 100644
--- a/libc/system_properties/system_properties.cpp
+++ b/libc/system_properties/system_properties.cpp
@@ -63,7 +63,7 @@
   ErrnoRestorer errno_restorer;
 
   if (initialized_) {
-    contexts()->ResetAccess();
+    contexts_->ResetAccess();
     return true;
   }
 
@@ -74,19 +74,19 @@
 
   if (is_dir(property_filename_)) {
     if (access("/dev/__properties__/property_info", R_OK) == 0) {
-      new (&contexts_union_.contexts_serialized) ContextsSerialized();
-      if (!contexts_union_.contexts_serialized.Initialize(false, property_filename_, nullptr)) {
+      contexts_ = new (contexts_data_) ContextsSerialized();
+      if (!contexts_->Initialize(false, property_filename_, nullptr)) {
         return false;
       }
     } else {
-      new (&contexts_union_.contexts_split) ContextsSplit();
-      if (!contexts_union_.contexts_split.Initialize(false, property_filename_, nullptr)) {
+      contexts_ = new (contexts_data_) ContextsSplit();
+      if (!contexts_->Initialize(false, property_filename_, nullptr)) {
         return false;
       }
     }
   } else {
-    new (&contexts_union_.contexts_pre_split) ContextsPreSplit();
-    if (!contexts_union_.contexts_pre_split.Initialize(false, property_filename_, nullptr)) {
+    contexts_ = new (contexts_data_) ContextsPreSplit();
+    if (!contexts_->Initialize(false, property_filename_, nullptr)) {
       return false;
     }
   }
@@ -100,8 +100,8 @@
   }
   strcpy(property_filename_, filename);
 
-  new (&contexts_union_.contexts_serialized) ContextsSerialized();
-  if (!contexts_union_.contexts_serialized.Initialize(true, property_filename_, fsetxattr_failed)) {
+  contexts_ = new (contexts_data_) ContextsSerialized();
+  if (!contexts_->Initialize(true, property_filename_, fsetxattr_failed)) {
     return false;
   }
   initialized_ = true;
@@ -113,7 +113,7 @@
     return -1;
   }
 
-  prop_area* pa = contexts()->GetSerialPropArea();
+  prop_area* pa = contexts_->GetSerialPropArea();
   if (!pa) {
     return -1;
   }
@@ -127,7 +127,7 @@
     return nullptr;
   }
 
-  prop_area* pa = contexts()->GetPropAreaForName(name);
+  prop_area* pa = contexts_->GetPropAreaForName(name);
   if (!pa) {
     async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
     return nullptr;
@@ -231,7 +231,7 @@
     return -1;
   }
 
-  prop_area* pa = contexts()->GetSerialPropArea();
+  prop_area* pa = contexts_->GetSerialPropArea();
   if (!pa) {
     return -1;
   }
@@ -269,12 +269,12 @@
     return -1;
   }
 
-  prop_area* serial_pa = contexts()->GetSerialPropArea();
+  prop_area* serial_pa = contexts_->GetSerialPropArea();
   if (serial_pa == nullptr) {
     return -1;
   }
 
-  prop_area* pa = contexts()->GetPropAreaForName(name);
+  prop_area* pa = contexts_->GetPropAreaForName(name);
   if (!pa) {
     async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
     return -1;
@@ -319,7 +319,7 @@
       return -1;
     }
 
-    prop_area* serial_pa = contexts()->GetSerialPropArea();
+    prop_area* serial_pa = contexts_->GetSerialPropArea();
     if (serial_pa == nullptr) {
       return -1;
     }
@@ -364,7 +364,7 @@
     return -1;
   }
 
-  contexts()->ForEach(propfn, cookie);
+  contexts_->ForEach(propfn, cookie);
 
   return 0;
 }