proprietary_vendor_xiaomi_sm8450-common/proprietary/system_ext/etc/init/tcmd.rc

# Copyright (c) 2021 Qualcomm Technologies, Inc.
# All Rights Reserved.
# Confidential and Proprietary - Qualcomm Technologies, Inc.

#start tcmd
service tcmd /system/system_ext/bin/tcmd
    class late_start
    socket tcmd  stream 660 root inet
    group system readproc inet radio wakelock oem_2901
    user system
    disabled

on property:persist.vendor.tcmd.feature=1
    start tcmd

on property:persist.vendor.tcmd.feature=0
    stop tcmd