platform_system_core/logcat/logcatd.rc

#
# init scriptures for logcatd persistent logging.
#
# Make sure any property changes are only performed with /data mounted, after
# post-fs-data state because otherwise behavior is undefined. The exceptions
# are device adjustments for logcatd service properties (persist.* overrides
# notwithstanding) for logd.logpersistd.size and logd.logpersistd.buffer.

# persist to non-persistent trampolines to permit device properties can be
# overridden when /data mounts, or during runtime.
on property:persist.logd.logpersistd.size=256
    setprop persist.logd.logpersistd.size ""
    setprop logd.logpersistd.size ""

on property:persist.logd.logpersistd.size=*
    # expect /init to report failure if property empty (default)
    setprop logd.logpersistd.size ${persist.logd.logpersistd.size}

on property:persist.logd.logpersistd.buffer=all
    setprop persist.logd.logpersistd.buffer ""
    setprop logd.logpersistd.buffer ""

on property:persist.logd.logpersistd.buffer=*
    # expect /init to report failure if property empty (default)
    setprop logd.logpersistd.buffer ${persist.logd.logpersistd.buffer}

on property:persist.logd.logpersistd=logcatd
    setprop logd.logpersistd logcatd

# enable, prep and start logcatd service
on load_persist_props_action
    setprop logd.logpersistd.enable true

on property:logd.logpersistd.enable=true && property:logd.logpersistd=logcatd
    # all exec/services are called with umask(077), so no gain beyond 0700
    mkdir /data/misc/logd 0700 logd log
    start logcatd

# stop logcatd service and clear data
on property:logd.logpersistd.enable=true && property:logd.logpersistd=clear
    setprop persist.logd.logpersistd ""
    stop logcatd
    # logd for clear of only our files in /data/misc/logd
    exec - logd log -- /system/bin/logcat -c -f /data/misc/logd/logcat -n ${logd.logpersistd.size:-256}
    setprop logd.logpersistd ""

# stop logcatd service
on property:logd.logpersistd=stop
    setprop persist.logd.logpersistd ""
    stop logcatd
    setprop logd.logpersistd ""

on property:logd.logpersistd.enable=false
    stop logcatd

# logcatd service
service logcatd /system/bin/logcatd -L -b ${logd.logpersistd.buffer:-all} -v threadtime -v usec -v printable -D -f /data/misc/logd/logcat -r 1024 -n ${logd.logpersistd.size:-256} --id=${ro.build.id}
    class late_start
    disabled
    # logd for write to /data/misc/logd, log group for read from log daemon
    user logd
    group log
    writepid /dev/cpuset/system-background/tasks