platform_system_core/bootstat/bootstat.rc

# This file is the LOCAL_INIT_RC file for the bootstat command.

on post-fs-data
    mkdir /data/misc/bootstat 0700 root root

# Record the time at which the user has successfully entered the pin to decrypt
# the device, /data is decrypted, and the system is entering the main boot phase.
#
# post-fs-data: /data is writable
# property:init.svc.bootanim=running: The boot animation is running
# property:ro.crypto.type=block: FDE device
on post-fs-data && property:init.svc.bootanim=running && property:ro.crypto.type=block
    exec - root root -- /system/bin/bootstat -r post_decrypt_time_elapsed

# sys.logbootcomplete is a signal to enable the bootstat logging mechanism.
# This signaling is necessary to prevent logging boot metrics after a runtime
# restart (e.g., adb shell stop && adb shell start).  /proc/uptime is not reset
# during a runtime restart, which leads to false boot time metrics being reported.
#
# The 'on boot' event occurs once per hard boot (device power on), which
# switches the flag on. If the device performs a runtime restart, the flag is
# switched off and cannot be switched on until the device hard boots again.

# Enable bootstat logging on boot.
on boot
    setprop sys.logbootcomplete 1

# Disable further bootstat logging on a runtime restart. A runtime restart is
# signaled by the zygote stopping.
on property:init.svc.zygote=stopping
    setprop sys.logbootcomplete 0

# Record boot complete metrics.
on property:sys.boot_completed=1 && property:sys.logbootcomplete=1
    # Record boot_complete and related stats (decryption, etc).
    exec - root root -- /system/bin/bootstat --record_boot_complete

    # Record the boot reason.
    exec - root root -- /system/bin/bootstat --record_boot_reason

    # Record time since factory reset.
    exec - root root -- /system/bin/bootstat --record_time_since_factory_reset

    # Log all boot events.
    exec - root root -- /system/bin/bootstat -l