init.te: allow writing to /sys/kernel/debug/tracing/tracing_on

Needed to disable tracing. See frameworks/native/cmds/atrace/atrace.rc

Also allow shell getattr access to the tracing file. That way
"ls -la" returns something meaningful.

Bug: 26217098
Change-Id: I4eee1aff1127db8945612133c8ae16c34cfbb786

init.te

@@ -108,6 +108,9 @@ allow init { sysfs_type debugfs_type }:{ dir file lnk_file } relabelto;
 allow init dev_type:dir create_dir_perms;
 allow init dev_type:lnk_file create;
 
+# Disable tracing by writing to /sys/kernel/debug/tracing/tracing_on
+allow init debugfs_tracing:file w_file_perms;
+
 # chown/chmod on pseudo files.
 allow init { fs_type -contextmount_type -sdcard_type -rootfs }:file { open read setattr };
 allow init { fs_type -contextmount_type -sdcard_type -rootfs }:dir  { open read setattr search };

shell.te

@@ -71,6 +71,7 @@ set_prop(shell, powerctl_prop)
 # systrace support - allow atrace to run
 allow shell debugfs_tracing:dir r_dir_perms;
 allow shell debugfs_tracing:file rw_file_perms;
+allow shell debugfs_trace_marker:file getattr;
 allow shell atrace_exec:file rx_file_perms;
 
 userdebug_or_eng(`