Add the sysrq_file special file and give ADB write access.

Change-Id: Ief2d412dddf4cefdf43a26538c4be060df4cc787

adbd.te

@@ -36,3 +36,6 @@ allow adbd shell:process noatsecure;
 # XXX Run screencap in a separate domain?
 binder_use(adbd)
 binder_call(adbd, surfaceflinger)
+
+# Write to the sysrq file
+allow adbd sysrq_file:file w_file_perms;

file.te

@@ -78,6 +78,8 @@ type security_file, file_type;
 type bluetooth_efs_file, file_type;
 # Downloaded files
 type download_file, file_type;
+# The sysrq special file
+type sysrq_file, file_type;
 
 # Socket types
 type adbd_socket, file_type;

file_contexts

@@ -208,3 +208,6 @@
 # asec containers
 /mnt/asec(/.*)?         u:object_r:asec_apk_file:s0
 /data/app-asec(/.*)?    u:object_r:asec_image_file:s0
+#############################
+# special /proc files
+/proc/sysrq-trigger  u:object_r:sysrq_file:s0