Database Develop

[help]magsisk echo script on boot

I want to make an echo command with magisk on boot
echo 0 > /sys/class/leds/button-backlight/max_brightness
so that it is applied on boot automatically
how to do that ?
thanks in advance

Just put your script in
Code:
/magisc/.core/service.d
and set execution permissions.
Since you want to edit sys files, you will need root permission. An example script would be (brightness.sh) :
Code:
#!/system/bin/sh
su -c 'echo 0 > /sys/class/leds/button-backlight/max_brightness'
Note :
If you want to execute your script at another boot stage you should have a look at this

pec0ra said:
Just put your script in
Code:
/magisc/.core/service.d
and set execution permissions.
Since you want to edit sys files, you will need root permission. An example script would be (brightness.sh) :
Code:
#!/system/bin/sh
su -c 'echo 0 > /sys/class/leds/button-backlight/max_brightness'
Note :
If you want to execute your script at another boot stage you should have a look at this
Click to expand...
Click to collapse
Can you tell what the -c flag in your example script is for?

Yaseen_the_Gamer said:
Can you tell what the -c flag in your example script is for?
Click to expand...
Click to collapse
https://github.com/topjohnwu/Magisk/blob/master/docs/tools.md#su
It's to use su directly in the command, basically.
Although in this case it's technically unnecessary since all Magisk boot scripts are run with superuser access.

[SOLVED] Cannot change LMK minfree values with script in /magisk/.core/service.d

Dear Community, dear Developers outside..
I'm using Magisk 14.0 on a Redmi Note 4 Snapdragon and super satisfied with it.
I just want to make simple changes like changing the lowmemorykiller minfree parameters - just like an init.d script in Kernel Adiutor..
Most of the commands are effective - but some of them are not..
This is what I want to apply for example:
chmod 666 /sys/module/lowmemorykiller/parameters/minfree
chown root /sys/module/lowmemorykiller/parameters/minfree
echo '7283,14566,21849,28928,36415,43698' > /sys/module/lowmemorykiller/parameters/minfree
..but does not work..
But these, for example.. these are working just fine:
echo '30' > /proc/sys/vm/swappiness
echo '0' > /sys/module/lowmemorykiller/parameters/enable_adaptive_lmk
echo '80' > /proc/sys/vm/overcommit_ratio
echo '400' > /proc/sys/vm/vfs_cache_pressure
echo '2430' > /proc/sys/vm/extra_free_kbytes
echo '4096' > /proc/sys/kernel/random/write_wakeup_threshold
echo '1024' > /sys/block/mmcblk0/queue/read_ahead_kb
echo '0' > /sys/block/mmcblk0/queue/iostats
echo '1' > /sys/block/mmcblk0/queue/add_random
echo '1024' > /sys/block/mmcblk1/queue/read_ahead_kb
echo '0' > /sys/block/mmcblk1/queue/iostats
echo '1' > /sys/block/mmcblk1/queue/add_random
swapoff /dev/block/zram0 > /dev/null 2>&1
echo '1' > /sys/block/zram0/reset
echo '0' > /sys/block/zram0/disksize
echo '1' > /sys/block/zram0/max_comp_streams
echo '524288000' > /sys/block/zram0/disksize
mkswap /dev/block/zram0 > /dev/null 2>&1
swapon /dev/block/zram0 > /dev/null 2>&1
echo '4096' > /proc/sys/kernel/random/read_wakeup_threshold
echo '4096' > /proc/sys/vm/min_free_kbytes
echo '0' > /proc/sys/vm/oom_kill_allocating_task
echo '90' > /proc/sys/vm/dirty_ratio
echo '70' > /proc/sys/vm/dirty_background_ratio
I do know that all I have to do is to put my script to one of these dirs - depending on when I want to run the scripts:
/magisk/.core/service.d
/magisk/.core/post-fs-data.d
But, as I mentioned - most of them has effect, some of them has no..
Any comment, any suggestion is more than appreciated.
Thank you!
[SOLVED] - solution is in post #5

Desperate bump..

I searched for help docs for service.d and post-fs-data.d but counldn't find them, can I ask you when each folder is executed, also does the scripts inside them must have .sh extension or not ?
I want to restart my systemui after boot complete, can you tell me if this script is ok ?
Code:
#!system/bin/sh
sleep 20
su
pkill -l TERM -f com.android.systemui
ps : the pkill command works fine after an "su" in terminal emulator
sorry for the offtopic !

@sheraro
https://github.com/topjohnwu/Magisk/blob/master/docs/README.MD

First of all: the solution for my issue was a simple sleep 30 in the services.sh to delay the start.. and I used an auxiliary file as well to make the changes (called from services.sh with 30sec delay, copied with the update-binary file directly, set permission to 0777 via config.sh) after that is all started working..
sheraro said:
I searched for help docs for service.d and post-fs-data.d but counldn't find them, can I ask you when each folder is executed, also does the scripts inside them must have .sh extension or not ?
I want to restart my systemui after boot complete, can you tell me if this script is ok ?
Code:
#!system/bin/sh
sleep 20
su
pkill -l TERM -f com.android.systemui
ps : the pkill command works fine after an "su" in terminal emulator
sorry for the offtopic !
Click to expand...
Click to collapse
So, second thing, @sheraro, I think you should delete the command su from your script because Magisk scripts are running as root anyway and if you issue su command it will start a shell with elevated privileges - an interactive shell, not what you want here, a sudo like command.. it works in the terminal because it is interactive but in the shell script if you start su it starts an interactive shell and it halts your script because it won't exit the shell you started.. and the next command will never run.. if you know what I mean.. but you don't need it anyway, because - as I mentioned - it is running as root anyway. +1: The syntax of the shebang is bad in your example, it is missing an exclamation mark. Can you re-test it like this:
Code:
#!/system/bin/sh
sleep 20
pkill -l TERM -f com.android.systemui
exit 0
.sh extension is not needed, the thing is: you have to set the correct permission in the config.sh like this:
Code:
set_permissions() {
# Default permissions, don't remove them
set_perm_recursive $MODPATH 0 0 0777 0777
[..omitted..]
Thing is: the files must have execute priv. and you can execute them like
Code:
$MODDIR/./desiredfilename
in the services.sh script.
Hope this helps.

crok.bic said:
.sh extension is not needed, the thing is: you have to set the correct permission in the config.sh like this:
Code:
set_permissions() {
# Default permissions, don't remove them
set_perm_recursive $MODPATH 0 0 0777 0777
[..omitted..]
Thing is: the files must have execute priv. and you can execute them like
Code:
$MODDIR/./desiredfilename
in the services.sh script.
Hope this helps.
Click to expand...
Click to collapse
I'm just pasting my script in service.d only, set permissions manually to 0777, corrected !#/system typo, removed su command, but no luck...
Where's services.sh and config.sh ?

sheraro said:
I'm just pasting my script in service.d only, set permissions manually to 0777, corrected !#/system typo, removed su command, but no luck...
Where's services.sh and config.sh ?
Click to expand...
Click to collapse
Reading your comment I think you are not developing a Magisk module, do you?
I do and this is why you have no idea where is config.sh, services.sh and the others I think.
If you just want to have some kind of "init.d script" support and run the script in your own phone *only* then your script should be in the folder /magisk/.core/service.d and it should have execute permission. That's all what you need - probably the sleep 20 is not enough, increase it to sleep 30 for instance.
If this is still not enough info I would suggest to read the Magisk documentation thoroughly (linked in post #4) and if you still stuck I suggest you to open your own thread, describe your problem thoroughly (what is your goal? what would you like to achive? how did you already try? what is happening but should not or not happening but you think it should happen? you know what I mean..) and ask the community. Probably you will be able to solve your issue in minutes/hours.

I changed it to sleep 100, same problem, you're right I should create a new thread for this.
I have a theme installed that mimics oreo style, but the systemUI is not themed until it's restarted, so I thought about a script executed after boot, anyway thanks for your help

It seems that sleep will delay the run of other modules' service.sh. is there any solution that will not affect other module?

nicorg3221 said:
It seems that sleep will delay the run of other modules' service.sh. is there any solution that will not affect other module?
Click to expand...
Click to collapse
I don't experience this behavior - what you described is the post-fs-data behavior.
I did the trick with a separate ("auxiliary") file and tried to explain how in post #5 but let me try again:
- created a file in the module's common folder (I gave the name `tweak`)
- this file starts with a shebang (it's a script..) and continues with a sleep 30 then comes my commands..
- then copied the file from the module to the Magisk module directory into /magisk/$MODDIR with the module file META-INF/com/google/android/update-binary (I added it to the copy section, manually.. I know, I know, it should work automagically anyway, but did not work and I was fed up with the coding, so hardcoded it.. sorry)
- I set the default file permission to 0777 in config.sh (yes, 0777, this is loose AF but works.. and I don't really care, the file contains code that can make the device *better* and has no suid bit set, so there is only little to no room to harm anything..)
- then I included a call in my module's common/service.sh like $MODDIR/./tweak to start my script
- when the tweak script starts it will start with the sleep 30 so implements the delay.. BUT!
- Because services.sh files from the modules are called parallelly by Magisk (by default, by it's nature, by it's code.. you got it) my module does not delays others - but still has the delay.
Hope this helps.

sheraro said:
I changed it to sleep 100, same problem, you're right I should create a new thread for this.
I have a theme installed that mimics oreo style, but the systemUI is not themed until it's restarted, so I thought about a script executed after boot, anyway thanks for your help
Click to expand...
Click to collapse
Pleased to help you - but honestly, if the only task you need is to kill and restart systemUI then I would do it via init.d script run by an app that mimics init.d scripting, or using a kernel that supports init.d scripts (if only you want to use that theme). It's just less complex for you I think, but honestly, a simple script file that has execute permission in /magisk/.core/services.d/ gives you 100% the same solution.

crok.bic said:
I don't experience this behavior - what you described is the post-fs-data behavior.
I did the trick with a separate ("auxiliary") file and tried to explain how in post #5 but let me try again:
- created a file in the module's common folder (I gave the name `tweak`)
- this file starts with a shebang (it's a script..) and continues with a sleep 30 then comes my commands..
- then copied the file from the module to the Magisk module directory into /magisk/$MODDIR with the module file META-INF/com/google/android/update-binary (I added it to the copy section, manually.. I know, I know, it should work automagically anyway, but did not work and I was fed up with the coding, so hardcoded it.. sorry)
- I set the default file permission to 0777 in config.sh (yes, 0777, this is loose AF but works.. and I don't really care, the file contains code that can make the device *better* and has no suid bit set, so there is only little to no room to harm anything..)
- then I included a call in my module's common/service.sh like $MODDIR/./tweak to start my script
- when the tweak script starts it will start with the sleep 30 so implements the delay.. BUT!
- Because services.sh files from the modules are called parallelly by Magisk (by default, by it's nature, by it's code.. you got it) my module does not delays others - but still has the delay.
Hope this helps.
Click to expand...
Click to collapse
I have my script in starting in .Core. Maybe that's the problem

nicorg3221 said:
I have my script in starting in .Core. Maybe that's the problem
Click to expand...
Click to collapse
..then it is in the wrong dir.. it is clearly described in the Magisk documentation.

I have researched a bit. I think you can use getprop sys.boot_completed to check if boot is completed. We should run init.d scripts after boot is completed instead of just wait for 30/100 seconds.
I place all my init.d scripts I want to run in /magisk/.core/service.d/init.d.
Then, I have a service.d script [exec_init_d.sh] in /magisk/.core/service.d. Magisk will run exec_init_d.sh when boot.
exec_init_d.sh will wait for sys.boot_completed and run all the files in /magisk/.core/service.d/init.d after boot completed
exec_init_d.sh
Code:
#!/system/bin/sh
# Please don't hardcode /magisk/modname/... ; instead, please use $MODDIR/...
# This will make your scripts compatible even if Magisk change its mount point in the future
MODDIR=${0%/*}
# This script will be executed in late_start service mode
# More info in the main Magisk thread
if [ "$1" != "1" ]; then
$0 1 &
log -p i -t Magisk "start new instance to let Magisk boot stages proceed"
exit
fi
#param
RUNLOG=0
RETRY_INTERVAL=5 #in seconds
MAX_RETRY=60
EXEC_WAIT=3 #in seconds
INIT_D_DIR=$MODDIR/init.d
LOG_PATH=$MODDIR/debug.log
#init
retry=${MAX_RETRY}
#wait for boot completed
log -p i -t Magisk "wait for boot completed"
while (("$retry" > "0")) && [ "$(getprop sys.boot_completed)" != "1" ]; do
sleep ${RETRY_INTERVAL}
((retry--))
done
if (("$retry" == "0")); then
log -p i -t Magisk "boot not completed within maximum number of retry"
else
log -p i -t Magisk "boot completed"
fi
sleep ${EXEC_WAIT}
log -p i -t Magisk "init.d execution started from ${INIT_D_DIR}"
if (("${RUNLOG}" == "1")); then
/data/magisk/busybox run-parts $INIT_D_DIR &> $LOG_PATH
log -p i -t Magisk "init.d execution output written to $LOG_PATH"
else
/data/magisk/busybox run-parts $INIT_D_DIR
fi
log -p i -t Magisk "init.d execution completed"

[WORKAROUND] - Magisk Not Installed - [Module]

I have Magisk v18.1 installed on my OG Pixel running PixelDust ROM and noticed every so often it loses root access. When entering the Magisk Manager app it also shows Magisk Not Installed. I did some investigating and found that magiskd (magisk daemon) gets terminated at some point randomly. Further testing revealed I could restart it manually by issuing "magisk --daemon" via SSH/ADB root shell.
I wrote a simple module to keep the daemon running and haven't noticed the "Magisk Not Found" error since. The module is just a simple bash script executed as service on boot that checks every minute for the daemon and runs the "magisk --daemon" command as root if not running. I am just posting it here to see if it can help anyone else who's root access disappears randomly on v17-19.3.
Please be aware that this is my first module ever. It was also originally started via an init.d script instead of the service hook in magisk, though it should work exactly the same. I have also noticed it is not possible for my module to restart magiskd yet if it was killed manually by the user.
GIt Repo:
https://github.com/Geofferey/mgkdhelper
Magisk Repo Submission:
https://github.com/Magisk-Modules-Repo/submission/issues/404
Release:
UNINSTALL INITIAL v1.0.0 RELEASE BEFORE INSTALL!!!
If you fail to do so you will have the old version and current version running at same time.
Download:
Current Release v2.1.0
Major thanks to @jcmm11 & @char101 whose contributions are now officially included in this module.

I just wanna say God bless you for this module, my man. I was frustratingly having my Magisk daemon getting killed 2-3 times a day On my LG V20. Since installing your module for the past 4 days ive yet to encounter such an issue. I greatly appreciate you coming up w/a solution to a problem that was frustrating me to the max

Geofferey said:
I wrote a simple module to keep the daemon running and haven't noticed the "Magisk Not Found" error since.
Click to expand...
Click to collapse
Thanks for that module. Very good idea and it's working perfectly fine. :good:

Hi,
There is no /data/local/run directory by default on my phone (OP6 Pie). So I suggest that either you create it first or simply uses /data/local/tmp to store the pid. Also creating the directory first might be a good idea. If you add -q to the grep command there is no need to redirect the output.
Code:
#!/system/xbin/bash
PIDFILE=/data/local/tmp/magiskd-helper.pid
LOGFILE=/data/local/tmp/magiskd-helper.log
is_magisk_running() {
ps -a | grep -q [m]agiskd
}
if [ ! -d /data/local/tmp ]; then
mkdir -p /data/local/tmp
fi
if [ -f $PIDFILE ]; then
kill -9 `cat $PIDFILE`
fi
echo $$ > $PIDFILE
RETRIES=0
while true; do
sleep 60
if ! is_magisk_running; then
echo `date` >> $LOGFILE
echo 'Magisk daemon appears to have crashed' >> $LOGFILE
echo 'Restarting magiskd...' >> $LOGFILE
/sbin/magisk --daemon
if is_magisk_running; then
echo 'Success!' >> $LOGFILE
RETRIES=0
else
echo 'Failure!' >> $LOGFILE
((++RETRIES))
if (( $RETRIES > 10 )); then
echo 'Giving up' >> $LOGFILE
break
fi
fi
echo >> $LOGFILE
fi
done

When first run, /system/bin/ps is linked to magisk builtin busybox, which don't have the -u option
Code:
ps: invalid option -- u
BusyBox v1.30.1-topjohnwu (2019-04-30 01:01:15 EDT) multi-call binary.
Usage: ps [-o COL1,COL2=HEADER] [-T]
Show list of processes
-o COL1,COL2=HEADER Select columns for display
-T Show threads

char101 said:
When first run, /system/bin/ps is linked to magisk builtin busybox, which don't have the -u option
Code:
ps: invalid option -- u
BusyBox v1.30.1-topjohnwu (2019-04-30 01:01:15 EDT) multi-call binary.
Usage: ps [-o COL1,COL2=HEADER] [-T]
Show list of processes
-o COL1,COL2=HEADER Select columns for display
-T Show threads
Click to expand...
Click to collapse
Try again after having install the 'Busybox for NDK' Magisk module (from osm0sis), maybe that the -u arg for ps command will works i ddon't remember me having testing it recently so idk if it will works but i think yeah

I have the GNU coreutils module installed so it is not the problem.
Also the original module redirect stderr to /dev/null so unless you modify it you won't see the error like I posted before.
My modifications
service.sh
Code:
#!/system/bin/sh
# Do NOT assume where your module will be located.
# ALWAYS use $MODDIR if you need to know where this script
# and module is placed.
# This will make sure your module will still work
# if Magisk change its mount point in the future
MODDIR=${0%/*}
# This script will be executed in late_start service mode
$MODDIR/common/magisk-monitor > /data/local/tmp/magisk-monitor.log 2>&1 &
magisk-monitor
Code:
#!/system/bin/sh
is_magisk_running() {
ps -A | grep -q [m]agiskd
}
sleep 300
echo `date`
echo 'magisk-monitor running'
echo
RETRIES=0
while true; do
sleep 60
if ! is_magisk_running; then
echo `date`
echo 'Magisk daemon appears to have crashed'
echo 'Restarting magiskd...'
/sbin/magisk --daemon
if is_magisk_running; then
echo 'Success!'
RETRIES=0
else
echo 'Failure!'
((++RETRIES))
if (( $RETRIES > 10 )); then
echo 'Giving up'
break
fi
fi
echo
fi
done

Rom said:
Try again after having install the 'Busybox for NDK' Magisk module (from osm0sis), maybe that the -u arg for ps command will works i ddon't remember me having testing it recently so idk if it will works but i think yeah
Click to expand...
Click to collapse
I doubt it... From busybox.net:
ps
Report process status
Options:
-o col1,col2=header Select columns for display
-T Show threads
Click to expand...
Click to collapse

It is better to just use 'ps -A' which will work on busybox ps and coreutils ps.

Didgeridoohan said:
I doubt it... From busybox.net:
Click to expand...
Click to collapse
I'm agree with u, but it was already happen for me that some other args works too, i had never know why.

I came across your module while looking for the same issue affecting many users on different devices (although it seems to be affecting Pie only). Magisk GitHub is also full of reports by people losing root and solving with a reboot. I don't know how impactful it is on the battery since it checks for Magisk every 60 seconds (I have just installed it) but so far your module is the only blessing we can get to avoid rebooting once/twice per day. I think you should definitely submit your module to the official repository!
P.s i had to create /data/local/run first for the pid

@Geoffrey another quick correction: in my case on MIUI 10 based on Pie, ps -a does not show the same output as ps -A. So I had to replace the -a in your script with an upper case A.

char101 said:
It is better to just use 'ps -A' which will work on busybox ps and coreutils ps.
Click to expand...
Click to collapse
Coreutils doesn't have a ps applet. If you want to use -u just use the full path /system/bin/ps to force the toybox applet.

@Geoffrey
First of all nice workaround. I did some cleanup and a few modifications if you want to post it to the Magisk repository (and I think you should).
Changed over to the current template.
Removed all the PID stuff, it's really not needed.
Replaced ps -a -u with pgrep. That eliminates any busybox vs toybox issues (at least the way it's being used here)
Removed bash. There's nothing here that requires a bash shell as opposed to the default shell.
Moved the script to it's own directory instead of xbin. Not all phones have xbin, and trying to use it on those that don't is problematic. Plus there's no reason the script needs to be in the PATH.
Added nohup to the script startup command in service.sh
Also always create the log file, with a "started on" line in it. That at least gives an indication that the script started.
So what we're left with.
mgkd-helper (in a script directory)
Code:
#!/system/bin/sh
LOGFILE=/data/local/tmp/magiskd-helper.log
rm -f $LOGFILE
echo "Started " $(date) >> $LOGFILE
echo "-----------------------------" >> $LOGFILE
echo >> $LOGFILE
while true; do
sleep 60
if ! pgrep magiskd >/dev/null; then
echo $(date) >> $LOGFILE
echo "Magisk daemon appears to have crashed" >> $LOGFILE
echo "Restarting magiskd..." >> $LOGFILE
if magisk --daemon; then
echo "success!" >> $LOGFILE
else
echo "failure!" >> $LOGFILE
fi
echo >> $LOGFILE
fi
done
service.sh
Code:
#!/system/bin/sh
# Do NOT assume where your module will be located.
# ALWAYS use $MODDIR if you need to know where this script
# and module is placed.
# This will make sure your module will still work
# if Magisk change its mount point in the future
MODDIR=${0%/*}
# This script will be executed in late_start service mode
#Magisk Daemon Helper
# Copyright (C) 2019 Geofferey @ XDA
# License: GPL V3+
nohup $MODDIR/script/mgkd-helper > /dev/null &
If you do decide to place it in the repository you need to do something with README.md
You should also replace META-INF/com/google/android/update-binary with the attached version. The included version is for standalone installs. Repository versions should use the alternate one. (Remove the ".txt")
Last note: tested this and it does work. I killed the running magiskd and a new one was started, with the appropriate log entry created

I wasn't able to start magiskd with "magisk -- daemon" via adb. It always says "No daemon found" instead of starting it. I seem to have lost root with the original script and I had to restart again. Any idea? I just enabled root via adb in Magisk. Not sure if that was the issue that I couldn't restart it.
And it seems like magiskd is killed in OxygenOS 9.0.5 on my OnePlus 6. Not sure if it is due to out of memory reasons but I can't get any logcat as I don't have root. Super annoying.

Will this be added to the magisk module repository? If it is there I couldn't find it. I do know there are links and a revision at the end of the thread by @jcmm11. I don't need the module, just curious if the revision will be put there eventually. I have had others with that problem that I have helped.
Thanks

martyfender said:
Will this be added to the magisk module repository? If it is there I couldn't find it. I do know there are links and a revision at the end of the thread by @jcmm11. I don't need the module, just curious if the revision will be put there eventually. I have had others with that problem that I have helped.
Thanks
Click to expand...
Click to collapse
I think it should be but it's up to @Geoffrey. It's his module. I cleaned it up a bit that's all. Most of the work is done. Biggest thing left to do is modify README.md

jcmm11 said:
@Geoffrey
First of all nice workaround. I did some cleanup and a few modifications if you want to post it to the Magisk repository (and I think you should).
Changed over to the current template.
Removed all the PID stuff, it's really not needed.
Replaced ps -a -u with pgrep. That eliminates any busybox vs toybox issues (at least the way it's being used here)
Removed bash. There's nothing here that requires a bash shell as opposed to the default shell.
Moved the script to it's own directory instead of xbin. Not all phones have xbin, and trying to use it on those that don't is problematic. Plus there's no reason the script needs to be in the PATH.
Added nohup to the script startup command in service.sh
Also always create the log file, with a "started on" line in it. That at least gives an indication that the script started.
So what we're left with.
mgkd-helper (in a script directory)
service.sh
If you do decide to place it in the repository you need to do something with README.md
You should also replace META-INF/com/google/android/update-binary with the attached version. The included version is for standalone installs. Repository versions should use the alternate one. (Remove the ".txt")
Last note: tested this and it does work. I killed the running magiskd and a new one was started, with the appropriate log entry created
Click to expand...
Click to collapse
Should we directly flash zip in twrp recovery

kryshnakishore said:
Should we directly flash zip in twrp recovery
Click to expand...
Click to collapse
You can flash it in recovery or via Magisk Manager, modules section, big + button at bottom of screen.

I've been looking for a solution to this since v17 ... started happening on 17, kept happening on 18, is even worse now on v19 ... :-/

How To Guide How to run a script at every boot using Magisk

How to run a script at every boot using Magisk
Note:
I tested the instructions below with Magisk 24.3 . They may or may not work with other versions of Magisk
Another very useful feature from Magisk that can also be used without creating a Magisk Module is the ability to start scripts after booting the phone:
To execute scripts after rebooting the phone just copy them to one of the directories
/data/adb/post-fs-data.d
/data/adb/service.d
on the phone, make the script executable (chmod +x scriptname) and reboot the phone.
(See also https://github.com/topjohnwu/Magisk/blob/master/docs/guides.md#boot-scripts)
Because the mapping will be done while booting the phone it will also survive updating the OS on the phone to a new version as long as the user data is not deleted and Magisk is installed.
To remove the script just delete the script and reboot the phone.
In case the phone does not boot anymore after adding the script just boot the phone from a recovery with adb support, for example from the TWRP:
Code:
# boot the phone into the bootloader and then do
sudo fastboot boot /data/backup/ASUS_ZENFONE8/twrp/twrp-3.6.1_12-1-I006D.img
Then connect via "adb shell" to the phone and delete the script .
I used this method to correct the SELinux context for the NFC device in the first version of AospExtended 9.0 for the ASUS Zenfone 8 (the device tree is recreated from scratch each time the phone boots so the change must be done after every reboot):
Code:
cat /data/adb/service.d/correct_dev_pn553.sh
#!/system/bin/sh
NFC_DEVICE="/dev/pn553"
echo ""
echo "The SELinux context for \"${NFC_DEVICE}\" is now:"
ls -lZ ${NFC_DEVICE}
echo ""
echo "Correcting the SELinux context for the NFC device \"${NFC_DEVICE}\" ..."
chcon -v u:object_r:nfc_device:s0 /dev/pn553
echo ""
echo "The SELinux context for \"${NFC_DEVICE}\" is now:"
ls -lZ ${NFC_DEVICE}
Again, if the script is tested and working you should create a Magisk module for it.
Update 06.06.2022 20:27
Corrected a minor typo
Update 18.06.2022
Corrected a typo : chmod -x must be chmod +x.
(Thanks to oldman20 for the hint)
​Update 26.06.2022​Fixed minor typos in the title of the post
Update 18.01.2023
See How to change any file or directory using Magisk for how to use this method change files on read-only mounted filesystems.

bnsmb said:
on the phone, make the script executable (chmod -x scriptname) and reboot the phone.
Click to expand...
Click to collapse
Correctly is chmod +x scriptname, right?

oldman20 said:
Correctly is chmod +x scriptname, right?
Click to expand...
Click to collapse
Yes, thanks for the hint . I corrected the post

How To Guide How to enable access via adb on a new installed OS

For automatic installation and configuration of a phone running the Android OS the access via adb is required. "Unfortunately" the access via adb is disabled in most Android distributions (in reality it is of course good that the access via adb is disabled in the default setting! See also the notes regarding the LineageOS at the end of this post))
There are (at least) two ways to enable access via adb:
Manually via the GUI of Android on the phone or via the Android command settings executed by the user root in a shell ,e.g.:
Bash:
settings put global development_settings_enabled 1
settings put global adb_enabled 1
The latter can also be done in a script in an adb shell -- but of course we need a working adb connection ....
One way around this problem is to use Magisk:
In principle this could be done using an init script for Magisk:
Magisk allows to run scripts while booting the phone (see How to run a script at every boot using Magisk); this feature could be used to enable adb via script.
Unfortunately, this method no longer works in the latest Android versions (Androd 12 and Android 13; Android 11 not tested):
Android now uses encryption for most of the files in the subdirectories in /data and to initiate the encryption keys for the files in these directories, the phone must boot once from the installed OS.
To use a Magisk init script to enable the access via adb, we need to create files in the directories /data/adb and /data/misc/adb. If you create these files while booting into TWRP recovery without a configured Android operating system, these files will be created unencrypted, making it impossible to boot the installed Android operating system:
If the Android operating system finds unencrpyted files in these directories at the first reboot, it boots into the installed recovery with the famous error message "Cannot load Android system. Your data may be corrupt" (see How to fix the error "Cannot load Android system. Your data may be corrupt" for details)
Fortunately, the Android operating system does not encrypt files in the directory /data/recovery (and therefore continues booting if there are already files in that directory) and the part of Magisk in the boot partition does not need the Magisk files /data/adb.
So to enable the access via adb using Magisk, we can create a script in the directory /data/recovery and a new Init .rc file for the Android operating system to execute that script while the Android OS is booting - for details about how to do that see How to trigger an action when a property is changed.
The working method to enable adb via Magisk is as follows:
- Boot the phone from a recovery (like TWRP)
- Install the new OS image but do not reboot the phone (see How to install an OS image using the TWRP binary twrp for how to install the OS via the cli commands from TWRP)
- Install Magisk into the boot partition of the phone and delete all files in /data/adb afterwards (see How to install Magisk into the boot partition using a script for how to install Magisk via script)
- copy a script to the directory /data/recovery on the phone that will enable access via adb using the Android command settings and copy the public ssl keys for the access via adb to the directory /data/misc/adb on the phone
- install a new init .rc file via Magisk which executes the script in the direcory /data/recovery to enable the access via adb - this script will be executed while doing the 1st reboot of the new installed Android OS.
(see How to trigger an action when a property is changed for how to add a new init .rc file using Magisk)
- reboot the phone
I wrote two scripts to enable adb using this method:
enable_adb_using_magisk.sh
The script enable_adb_using_magisk.sh must run in an adb session in TWRP after the new OS was installed and after Magisk has been installed into the boot partition but before the first reboot of the new installed operating system.
The script enable_adb_using_magisk.sh
- creates the script /data/recover/enable_adb_via_service.sh on the phone to enable adb and install the public ssl key for access via adb
- creates a new init *rc file using Magisk that will run the script /data/recover/enable_adb_via_service.sh on the phone while doing the 1st reboot (after the file encryption for the files /data is initalized by the Android OS)
To use the script enable_adb_using_magisk.sh manually after installing the new OS and Magisk do while the phone is booted into TWRP:
Bash:
#
# copy the script enable_adb_using_magisk.sh to the directory /tmp on the phone
#
adb push enable_adb_using_magisk.sh /tmp/enable_adb_using_magisk.sh
# copy the public ssl key for access via adb to the directory /tmp on the phone
#
adb push $HOME/.android/adbkey.pub /tmp/adbkey.pub
# execute the script /tmp/enable_adb_using_magisk.sh on the phone
#
adb shell sh /tmp/enable_adb_using_magisk.sh
# reboot the phone into the new installed OS
#
adb reboot
Notes:
The script enable_adb_using_magisk.sh installs the init *rc file into the boot partition from the slot for the next reboot: In this scenario this is the slot with the new installed OS.
To specify the boot partition to use add the boot partition as parameter, e.g.
Bash:
adb shell sh /tmp/enable_adb_using_magisk.sh _a
The init *rc service used is:
Spoiler: init *rc service to enable adb
Code:
#
# additional RC service to enable the access via adb after the 1st boot into the new installed Android OS
#
service bnsmb_enable_adb /system/bin/sh /data/recovery/enable_adb_via_service.sh
user root
group root
seclabel u:r:magisk:s0
disabled
oneshot
on zygote-start
setprop sys.bnsmb_enable_adb_done 0
start bnsmb_enable_adb
#
# Note: the following entries are for testing only!
#
on zygote-start
write /data/recovery/semfile Here_I_am
setprop sys.bnsmb.test.okay 0
The script enable_adb_using_magisk.sh creates the files adb_keys and adb_temp_keys.xml in the directory /data/misc/adb if the public ssl key /tmp/adbkey.pub exists on the phone.
Note that the file /data/misc/adb/db_temp_keys.xml is an Android Binary XML fIle (see How to change files in Android XML Binary format for details about Android Binary XML files)
To avoid the manual steps listed above I wrote another script:
enable_access_via_adb.sh
The script enable_access_via_adb.sh does all the steps listed above; the usage for enable_access_via_adb.sh is
Code:
[ OmniRom 13 Dev - [email protected] /data/develop/android/scripts_on_linux ] $ ./enable_access_via_adb.sh -h
enable_access_via_adb.sh version - v1.0.0.0 - shell script to enable adb access via an init .rc file configured via Magisk
enable_access_via_adb.sh [-h|help|-H] [--reboot|--noreboot] [--nopubkey|--pubkey]
[ OmniRom 13 Dev - [email protected] /data/develop/android/scripts_on_linux ] $
Spoiler: Detailed Usage
Code:
[ OmniRom 13 Dev - [email protected] /data/develop/android/scripts_on_linux ] $ ./enable_access_via_adb.sh -H
enable_access_via_adb.sh version - v1.0.0.0 - shell script to enable adb access via an init .rc file configured via Magisk
Usage
enable_access_via_adb.sh [-h|help|-H] [--reboot|--noreboot] [--nopubkey|--pubkey]
All parameter are optional. The parameter can be used in any order.
Use the parameter "help" or "-H" to print the detailed usage help; use the parameter "-h" to print only the short usage help
If the parameter "--reboot" is used the script will reboot the phone after installing Init .rc file; to disable the automatic reboot use the parameter "--noreboot".
Default is to ask the user for confirmation to reboot the phone.
Use the parameter "--nopubkey" to disable configuring the public key of the current user on the PC for the access via adb; use the parameter "--pubkey" to configure
the public key; default is to configure the public key.
The default public ssl key used is the key in the file "${HOME}/.android/adbkey.pub".
To change some of the values used by the script these environment variables can be set before starting the script:
Set the environment variable PUBLIC_KEY_ON_PC to the file with the public ssl key to use for the access via adb if another public key should be used
Set the environment variable REBOOT to "yes" before starting the script to automatically reboot the phone after enabling the root access
Set the environment variable REBOOT to "no" before starting the script to disable the automatic reboot after enabling the root access
See also the source code of the script
boot_phone_from_twrp.sh
for environment variables supported by this script
Prerequisites
- the phone must be connected via USB
- Magisk must be already installed in the boot partition of the phone
- the phone must be either booted into the fastbootd or bootloader with a working fastboot connection
or already booted into a recovery image with working adb connnection
The scripts boot_phone_from_twrp.sh and enable_adb_using_magisk.sh are required by this script -- see the source code of the script
[ OmniRom 13 Dev - [email protected] /data/develop/android/scripts_on_linux ] $
So installing a new OS and enabling access via adb in a script without user intervention can be done using these commands:
Bash:
#
# do a factory reset and install the OS image using the TRWP binary twrp
#
REBOOT=no ./install_os_via_twrp.sh factory_reset /data/backup/ASUS_ZENFONE8/omnirom_local/omni-13/omni-13-20221211-zenfone8-MICROG.zip
# install Magisk into the boot sector of the partition with the new OS and delete all files in /data/adb afterwards
#
# The parameter delete_adb_dir for the script "install_magisk_via_twrp.sh" is only available in version 2.2.0.0 or newer of the script.
#
REBOOT=no ./install_magisk_via_twrp.sh next copy_apk delete_adb_dir
# enable adb and copy the public keys for adb via new init *rc file using Magisk in the boot partition
#
REBOOT=no ./enable_access_via_adb.sh
# reboot the phone
#
adb reboot
# wait until the new OS is booted and adb is enabled
#
adb wait-for-device
# install the Magisk App
#
./install_apk.sh /data/backup/Android/EssentialApps/Magisk-v25.2.apk
# install the Magisk directories and binaries in /data/adb
#
REBOOT=no ./install_magisk_via_twrp.sh adb_only
# (optional) enable root access for the adb shell
#
REBOOT=yes ./init_magisk_db.sh
Notes:
The script enable_access_via_adb.sh needs the helper script boot_phone_from_twrp.sh.sh and the script enable_adb_using_magisk.sh .
The scripts can be downloaded from my homepage:
enable_access_via_adb.sh
enable_adb_using_magisk.sh
boot_phone_from_twrp.sh
The other scripts mentioned in ths post can also be downloaded from my home page:
install_os_via_twrp.sh (see How to install an OS image using the TWRP binary twrp for a descripton of this script)
install_magisk_via_twrp.sh (see How to install Magisk into the boot partition using a script for a description for this script)
install_apk.sh (see How to install packages (apk files) for Android via script for a description for this script)
init_magisk_db.sh (see How to enable root access using Magisk in a script for a description for this script)
Disabling the service to enable access via adb
To only run once, the script enable_adb_using_magisk.sh creates the file /data/recovery/adb_initialized exists on the phone. If that file already exists when enable_adb_using_magisk.sh starts, the script will do nothing and end immediately.
Therefor, it's not necessary to delete the new init *rc service.
It might even be useful to leave the service installed, since it can be used for other purposes later by modifying the script
However, if necessary, you can either delete the script used by the init *rc service enable_adb_using_magisk.sh or reinstall the original boot partition to get rid of the new service completely:
Bash:
#
# while the phone is booted into the Android OS with enabled root access or while the phone is booted into TWRP
#
# use the parameter "yes" for the script to run without requesting user input
#
adb shell su - -c /data/recovery/work/restore_boot_partition.sh
Directories and files used
Name
Type
Content
Comment
/tmp/adbkey.pubfilessl public key that should be configured/tmp is on a ramdisk so this file is lost after booting the phone/data/recovery/workDirectorytemporary files used for enabling adb/data/recovery/work/enable_adb_via_service.rcfileinit *rc file added to the boot partition via Magiks/data/recovery/work/boot_a.imgfileimage of the original boot partition/data/recovery/work/original_boot_partition.imgSymLinklink to the image with the original boot partition/data/recovery/work/restore_boot_partition.shfileScript to restore the boot partition using the image of the original boot partition/data/recovery/work/header
/data/recovery/work/kernel
/data/recovery/work/ramdisk.cpiofilescontents of the boot partition/data/recovery/adbkey.pubfilepublic ssl key to be configured for access via adb/data/recovery/adb_temp_keys.xml.humanfileXML file with the configuration for the access via adb
(will be converted to an XML file in Android binary XML format in /data/misc/adb)/data/recovery/enable_adb_via_service.shfilescript to enable the access via adb and installl the public ssl key for the access via adb
The script is configured in the init*rc file /data/recovery/work/enable_adb_via_service.rc/data/recovery/enable_adb_via_service.logfilelog file created by the script /data/recovery/enable_adb_via_service.sh/data/recovery/adb_initializedfilesemphor file for the script /data/recovery/enable_adb_via_service.sh - if this file exists the script will do nothing/data/recovery/semfilefiletest file created by the new init *rc service/data/recovery/log.gz
/data/recovery/last_log.gz
/data/recovery/recovery.fstab
/data/recovery/storage.fstabfileFiles created by TWRPonly for information
Enabling access via adb in the LineageOS (Update 11.01.2023)
In the LineageOS 19 for the ASUS Zenfone 8 access via adb is enabled in the default configuration.
Therefor these instructions are not necessary. The only configuration that must be done on a phone running the LineageOS is to copy the public ssl keys to /data/misc/adb to enable the access via adb.
Unfortunately the method used for this described in this post seems not to work in the LineageOS.
In addition, root access via adb can be enabled in the developer settings in the LineageOS. Until now I did not find out how to enable the plain root access from the LineageOS from within a script.
userdebug builds
In userdebug builds of Android the access via adb (without authentification) is enabled in the default.
Trouble Shooting
The script enable_adb_using_magisk.sh uses the log file /data/recovery/enable_adb_via_service.log if executed via init *rc service.
To check if the init *rc file was configured successfully check the properties
sys.bnsmb_enable_adb_done
sys.bnsmb.test.okay
in the running Android OS. Both properties should be defined with the value 0:
Code:
ASUS_I006D:/ # getprop sys.bnsmb_enable_adb_done
0
ASUS_I006D:/ #
ASUS_I006D:/ # getprop sys.bnsmb.test.okay
0
ASUS_I006D:/ #
In addition, if everything worked there should exist the file /data/recovery/semfile.
Code:
130|ASUS_I006D:/ # ls -l /data/recovery/semfile
-rw------- 1 root root 9 2022-12-29 11:44 /data/recovery/semfile
ASUS_I006D:/ #
Use the Android command start to check if the service exists and can be started, e.g.
Spoiler: start bnsmb_enable_adb
Code:
ASUS_I006D:/ # start bnsmb_enable_adb ; dmesg | tail -10
[ 3069.861365] [ 3069.861365] (CPU:2-pid:1:init) [12:35:31.711593934] init: Service 'exec 613 (/system/bin/flags_health_check UPDATABLE_CRASHING)' (pid 5734) exited with status 0 waiting took 0.024000 seconds
[ 3069.861402] [ 3069.861402] (CPU:2-pid:1:init) [12:35:31.711630236] init: Sending signal 9 to service 'exec 613 (/system/bin/flags_health_check UPDATABLE_CRASHING)' (pid 5734) process group...
[ 3069.861618] [ 3069.861618] (CPU:2-pid:1:init) [12:35:31.711846069] libprocessgroup: Successfully killed process cgroup uid 1000 pid 5734 in 0ms
[ 3071.202534] [ 3071.202486] (CPU:2-pid:5077:wk:0xffffffe40) [12:35:33.052716433] [BAT][CHG]asus_jeita_cc_worker set BATTMAN_OEM_WORK_EVENT : WORK_JEITA_CC
[ 3071.220807] [ 3071.220807] (CPU:0-pid:350:wk:0xffffffe40) [12:35:33.071038100] [BAT][CHG]handle_message set property:16 successfully
[ 3071.570753] [ 3071.570753] (CPU:2-pid:1:init) [12:35:33.420982631] init: starting service 'bnsmb_enable_adb'...
[ 3071.575971] [ 3071.575971] (CPU:3-pid:1:init) [12:35:33.426199819] init: Control message: Processed ctl.start for 'bnsmb_enable_adb' from pid: 5735 (start bnsmb_enable_adb)
[ 3071.614570] [ 3071.614570] (CPU:3-pid:1:init) [12:35:33.464799298] init: Service 'bnsmb_enable_adb' (pid 5736) exited with status 0 oneshot service took 0.040000 seconds in background
[ 3071.614609] [ 3071.614609] (CPU:3-pid:1:init) [12:35:33.464837267] init: Sending signal 9 to service 'bnsmb_enable_adb' (pid 5736) process group...
[ 3071.614788] [ 3071.614788] (CPU:3-pid:1:init) [12:35:33.465016277] libprocessgroup: Successfully killed process cgroup uid 0 pid 5736 in 0ms
ASUS_I006D:/ #
If something does not work execute the script manually in an adb session to check :
Spoiler: /data/recovery/enable_adb_via_service.sh
Code:
ASUS_I006D:/ # rm -f /data/recovery/adb_initialized
ASUS_I006D:/ #
ASUS_I006D:/ #
ASUS_I006D:/ # sh -x /data/recovery/enable_adb_via_service.sh
+ tty -s
+ '[' 0 -ne 0 ']'
+ PATH=/system/bin:/product/bin:/apex/com.android.runtime/bin:/apex/com.android.art/bin:/system_ext/bin:/system/bin:/system/xbin:/odm/bin:/vendor/bin:/vendor/xbin
+ export PATH
+ '[' ! -r /data/recovery/adb_initialized ']'
+ echo 'Sleeping 30 seconds now ...'
Sleeping 30 seconds now ...
+ sleep 30
+ touch /data/recovery/adb_initialized
+ settings put global development_settings_enabled 1
+ settings put global adb_enabled 1
+ '[' ! -d /data/misc/adb ']'
+ '[' ! -r /data/misc/adb/adb_keys ']'
+ '[' -r /data/recovery/adbkey.pub ']'
+ >>/data/misc/adb/adb_keys
+ cat /data/recovery/adbkey.pub
+ '[' -r /data/recovery/adb_temp_keys.xml.human ']'
+ xml2abx /data/recovery/adb_temp_keys.xml.human /data/misc/adb/adb_temp_keys.xml
+ chmod 0600 /data/misc/adb/adb_temp_keys.xml
+ chown system:shell /data/misc/adb/adb_temp_keys.xml
+ chcon -v u:object_r:adb_keys_file:s0 /data/misc/adb/adb_temp_keys.xml
chcon '/data/misc/adb/adb_temp_keys.xml' to u:object_r:adb_keys_file:s0
ASUS_I006D:/ #

Thank you for your explanation, I leave my footprint, I need this sometimes.