am 4ac5775d: Merge "Fix handling of wrapped processes [part 2]"

* commit '4ac5775d63791ae3635882a3b49f5ebc253262bb':
  Fix handling of wrapped processes [part 2]

core/java/com/android/internal/os/ZygoteInit.java

@@ -17,7 +17,6 @@
 package com.android.internal.os;
 
 import static android.system.OsConstants.POLLIN;
-import static android.system.OsConstants.POLLOUT;
 import static android.system.OsConstants.S_IRWXG;
 import static android.system.OsConstants.S_IRWXO;
 
@@ -276,6 +275,14 @@ public class ZygoteInit {
         long startTime = SystemClock.uptimeMillis();
 
         // Drop root perms while running static initializers.
+        final int reuid = Os.getuid();
+        final int regid = Os.getgid();
+
+        // We need to drop root perms only if we're already root. In the case of "wrapped"
+        // processes (see WrapperInit), this function is called from an unprivileged uid
+        // and gid.
+        boolean droppedPriviliges = false;
+        if (reuid == ROOT_UID && regid == ROOT_GID) {
             try {
                 Os.setregid(ROOT_GID, UNPRIVILEGED_GID);
                 Os.setreuid(ROOT_UID, UNPRIVILEGED_UID);
@@ -283,6 +290,9 @@ public class ZygoteInit {
                 throw new RuntimeException("Failed to drop root", ex);
             }
 
+            droppedPriviliges = true;
+        }
+
         // Alter the target heap utilization.  With explicit GCs this
         // is not likely to have any effect.
         float defaultUtilization = runtime.getTargetHeapUtilization();
@@ -335,7 +345,8 @@ public class ZygoteInit {
             // Fill in dex caches with classes, fields, and methods brought in by preloading.
             runtime.preloadDexCaches();
 
-            // Bring back root. We'll need it later.
+            // Bring back root. We'll need it later if we're in the zygote.
+            if (droppedPriviliges) {
                 try {
                     Os.setreuid(ROOT_UID, ROOT_UID);
                     Os.setregid(ROOT_GID, ROOT_GID);
@@ -344,6 +355,7 @@ public class ZygoteInit {
                 }
             }
         }
+    }
 
     /**
      * Load in commonly used resources, so they can be shared across