storaged: allow shell to call dumpsys storaged

Test: adb kill-server && adb shell dumpsys storaged
Bug: 36492915
Change-Id: I3a1a2ad2f016ddd5770d585cae82c8be69001df9

private/shell.te

@@ -10,3 +10,6 @@ allow shell atrace_exec:file rx_file_perms;
 # Run app_process.
 # XXX Transition into its own domain?
 app_domain(shell)
+
+# allow shell to call dumpsys storaged
+binder_call(shell, storaged)

private/storaged.te

@@ -21,6 +21,10 @@ userdebug_or_eng(`
   allow storaged debugfs_mmc:file r_file_perms;
 ')
 
+# Needed to provide debug dump output via dumpsys pipes.
+allow storaged shell:fd use;
+allow storaged shell:fifo_file write;
+
 # Binder permissions
 add_service(storaged, storaged_service)