Story of abandoning own tool in favour of learning multiple projects and combining them

Adopting Debian Installer  (time scale)

In 2016 I started to formalize the way I want to replicate my debian installation on other PCs. I think I needed that once per year.

That is indicated by git commits of a repo with numbered scripts -- stages of installing debian & my expected packages & modifications, after booting with a usb flash drive.

Disk-partitioning was hard (shrinking Windows partitions), configuring apt also forever evolving.

Prior to that I would have just reattach the disks and copied the filesystem.

After 6 years, in 2022 (having used those tools about 10 times) I started to suspect I could spend my time better by learning & fixing a publicly developed tool.

And indeed in April 2023 I tried out the debian-installer (the "hd-media" option), with some pre-seeding.

Then I needed more than pre-seed & targeting unstable/SID: I wanted to understand all possible disk encryption setups, and using my additional apt repository (+ apt configuration).

Experiments

So, I was using the build system in debian-installer (to build customizations) and decided to use a virtual PC (KVM-qemu) to quickly test the result.

I had to overcome bug 940801

I could test the partitioning with encryption on a virtual disk (10GB).

• Started to wonder about having "udeb" packages in my reprepro.
• Not really sure what is inside "mini.iso", maybe all is inside the initrd?

Setting up PXE

I wanted to also avoid using flash drives/sd-cards  -- using PXE seems more elegant. Also using netboot rather than hd-media seems a nice simplification.

But there's a catch: this requires modifying DHCP server (which I cannot do on my main modem/route), and I didn't want to set a separate dhcp just for this use-case (on a linux box, with the only connection to the booting PC).

Anyway, I started still with KVM -- a new "bridge" with dhcp pointing at local tftp.

I had to use signed grub to boot with secure-boot.

Going for physical PC

So I installed dd-wrt on another router/wifi access point, and detached from its "bridge" between all LAN connectors one connector which is then serviced by a new dhcp server, and advertises the necessary option for PXE boot.

 

First successful run

I included a custom udeb: I needed a modified "choose-mirror" to debug still flaky pre-seed configuration of the net interface.

Partitioning seems intuitive (once you want to use the same key for both Swap & Root fs).

Choose the minimal (ssh server, standard), and after the reboot  do still some manual copying, apt configuration, and finally install my  "top" virtual packages.

логическая загадка

Есть 5 космических кораблей (из разных стран мира). У каждого есть номер (1-5), цвет, маскот и каждый привозит сувенир из Луны. Они не стартуют в своей стране но приземляются в ней.  Нам известны следующие факты: 

 

1. Синий корабль стартует в Хирошиме (Япония)
2. Русский корабль привезёт с Луны "флаг США" (как сувенир) 
3. В Люнбурге (в каком же государстве ... дочитать до конца и узнаешь) стартует корабль номер 1. 
4. Кошка путешествует в корабле с номером на 1 меньше чем номер золотого корабля. 
5. Соловей является маскотом корабля, с номером на 1 больше чем у зелёного корабля. 
6. Корабль со средним номером привозит "лунарный пыл" (как сувенир). 
7. Улитка маскот корабля, который стартует на Байконуре (будем считать городом в России). 
8. Корабль который стартовал на мысе Каневерале (США) привезет "старую лунарную камеру" (=сувенир). 
9. Маскотом на красном корабле является жаба. 
10. Зелённый корабль принадлежит Китае. 
11. У Японии номер 2. 
12. Серебристый корабль принадлежит Германии. 
13. Корабль США стартует в Пекинге. 
14. Германия привезёт в Люнбург с Луны "космическоя авто" и имеет номер на 1 меньше чем Россия. 
    

 

Вся эта информация хватит для того, чтобы ответить на следующие 2 вопроса:

1. A. Который корабль имеет зебру как маскота? 
2. B. Который корабль привезёт "женшину" как сувенир?
   

 Working on Proof-of-concept

Based on my git segments/sums, I can construct a 

poset of modifications (micro-features), and 

study them in isolation. For the whole-picture study I use (modified) xdot with an extension to handle "gitk://" actions, so I can open gitk (restricted to the segment history) by clicking on single nodes:

git-hierarchy contains the "git-graph -x" command to open such a graph.

Keeping up with debian Sid

My small build system

I need to replace some distro packages with my improvements.

For this I need to patch the sources -- I only handle git. I need to be notified, warned, when a new version is needed.

So I patched apt to report when a switch from my version to the upstream would happen (due to  "apt dist-upgrade").

In such a case I run my  git-rebase-origin which rebases my feature poset (of feature branches/segments mixed into "merges") over a refreshed remote branch.

Then I run my scripts to invoke gbp(1) with a suitable version string, and create the deb packages & put them in reprepro.

the sequence of commands to maintain apt itself:


$ cd ~/git/apt/
$ git-rebase-origin  
# this deduces the upstream -- base of my feature branches.

$ release
# this detects I'm building my extension of upstream debian package, so deduces the correct version, build, uploads, tags, pushes, installs.

When I only want to test some changes, I run 

$ snap

which creates a .deb package, installs it, withouth any reprepro etc.

Logický test

5 lodí, každá má číslo, barvu, maskota a suvenýr z Měsíce.
Nestartují ze své země, ale přistávají v ní.

1. Modrá loď startuje v Hirošimě
2. SSSR přiveze z Měsíce vlajku USA
3. v Lunburgu startuje loď s číslem 1.
4. Kočka cestuje v lodi s číslem o 1 menším než je číslo zlaté lodi.
5 Slavík je maskotem lodi, jejíž start. číslo je o 1 vyšší než číslo zelené lodi.
6 Loď s prostředním číslem veze zpět měsíční prach.
7 Hlemýžd je maskot lodi, jež startuje na Bajkonuru.
8 Stát, který odstartoval na mysu Caneveral, příveze zpět starou měsíční kameru.
9 Maskot v červené lodi je žába.
10 Zelená loď patří Číně.
11 Japonsko má startovní číslo 2.
12 Stříbrná loď patří NSR.
13 Loď USA startuje v Pekingu.
14 NSR přiveze do Lunburgu z měsíce kosmické auto a má startovní číslo o 1 nižší než SSSR.


Tyto infomace stačí k tomu, abychom zodpověděli dvě otázky:

A. Která loď má jako maskota zebru?
B. Která loď přiveze zpět z měsíce ženu?

Upgrading Nubia 7 mini

I recently bought this  phone on marktplaats, already upgraded to Mokee Android 7. I liked the features, my previous phone used Android 4.2.
So I bought another one for my wife, this time I had to make the upgrade myself. It was not straightforward:

The first nubia used as recovery  TWRP 3.0.2-0, the other is with clockwork-mod (v6.0.5.0).

• I had to resize the big "grow" partition manually, i.e. merge it with "userdata".
• suddenly I saw disconnections of Wifi, and that was due to the same MAC address of the 2 nubias.

MAC address

So I searched for a solution to tune the MAC address. I found the hint on Intf0MacAddress in WCNSS_qcom_cfg.ini. But it did not work.

/data/misc/wifi/WCNSS_qcom_cfg.ini  nor  /system/etc/wifi/WCNSS_qcom_cfg.ini

So I had a workaround to

echo 98:6c:f5:63:ec:d0 > /sys/devices/fb000000.qcom,wcnss-wlan/wcnss_mac_addr

while in airplane mode.
In the end I  found /persist/WCNSS_qcom_cfg.ini which indeed works, and overrides the other 2 files.

ANDROID_SERIAL to distinguish them?

To have them accessible via adb at the same time, I need to distinguish by this serial number, which is unfortunately identical. For now I overwrite the kernel cmdline in img_info with "androidboot.serialno=XXX"

Proximity sensor

After receiving some (whatsapp) calls, I noticed it was almost impossible to get the screen back on, as expected.

So, as a workaround I turned off  in Phone> Settings> Accessibility> Use proximity sensor.

But Whatsapp does not seem to have this option.

So I installed Sensors test and some app to "reset/calibrate" but to no effect.

So I started to look for the kernel driver, to fix a possible bug. There are confusingly multiple kernel sources on github:

1. https://github.com/nx507j-dev/android_kernel_nubia_nx507j
2. https://github.com/ztemt/NX507J_5.1_kernel
3. https://github.com/MoKee/android_kernel_nubia_nx507j.git
4. https://github.com/MoKee/android_kernel_zte_nx507j.git

The 3rd is the one used on Mokee (my fixes in https://github.com/mmaruska/android_kernel_nubia_nx507j). The other ones fail when (Android) "init" configures (selinux) sepolicy.

Btw. failures of the other kernels can be seen thanks to android ram-console: after the failure, the phone reboots to recovery and 

adb shell cat /proc/last_kmsg

shows the problem.

In the end the problems is only the calibration, so 

 echo 500 > prox_threshold_low  

fixes the issue. To see this value, I did:

cd /sys/class/proximity/proximity/
echo 1 > prox_debug

and "dmesg -c" while running the sensor test app, to see:

[43580.286869] [SENSOR_ALS_PROX] [taos_prox_threshold_set: 2338] proxdata = 396

I guess it's stored in /persist/proxdata/threshold ?

Other issues

calendar/alarm database -- crash when entering the Alarm app:

android.database.sqlite.SQLiteException: Can't downgrade database from version 12 to 8

I removed the relevant file.

SystemUI crash due to wallpaper using too big image

java.lang.RuntimeException: Canvas: trying to draw too large(143769600bytes) bitmap.
....
AppCrashReceiver: com.android.systemui stopped unexpectedly...

rm  /data/system/user/0/wallpaper_*



My improvements (divided into feature-segments)  https://github.com/mmaruska/android_kernel_nubia_nx507j/network

Taming Android am command

In Android an intent can carry data of a certain mime type.
To test this feature, I had an App which sets up an IntentFilter, and then I would manually trigger it:

am broadcast -t text/xml -a my.action.START -d "file:///system/usr/share/mmc/settings.xml"

It did not work, so I had to read better about am options:

So I learned about FLAG_DEBUG_LOG_RESOLUTION (I also saw it in the sources). So I added "-t 8" as option.
Then I saw that the type used during the matching was Null, so I verified the binder transaction code:reading from binder tx data and writing tx data Here the writing:

ActivityManagerProxy
broadcastIntent()....
intent.writeToParcel(data, 0); // serializes the Intent
data.writeString(resolvedType); // separately adds the type

So the type has to be delivered separately, but am does not do it:

private void sendBroadcast() throws Exception {
Intent intent = makeIntent(UserHandle.USER_CURRENT);
IntentReceiver receiver = new IntentReceiver();
System.out.println("Broadcasting: " + intent);
// this is the fix null -> intent.getType()
mAm.broadcastIntent(null, intent, /* null */ intent.getType(), receiver, 0, null, null, mReceiverPermission,
android.app.AppOpsManager.OP_NONE, true, false, mUserId);
receiver.waitForFinish();
}