Linux on Android related question

[Diego Iastrubni]

Hi David,

On יום שישי, 26 בדצמבר 2014 15:54:12 David Harel wrote:
> My son purchased an Android phone in China (against my recommendation).
> It's a phone by Coolpad the module is 7620l
You should have a talk to your son ;-)

> Apparently the Android installation for Chinese is different than what we
> are used to get in "Western countries". No Google account, no Google play
> store and it seems that all network activities went through China (for
> inspection?, really slow on network activity).
Actually... not. GApps is not officially part of AOSP (which in my book is the 
definition of "android"... but the world is moving and my definition is becoming 
less correct as the name of Android advances in the english alphabet).

Nokia/MS did the same. Jolla are going this as well. The Android emulators 
usually do this as well.

> It took me a while to find English Rom for it and then some time to root it
> (temporarily - will explain later).
> Now I got Google account and other "Western" stuff but still:
> 1. Root is removed after reboot
> 2. Google play services crashes and so does the address book sync operation.
> 
> Looking at the article: http://elinux.org/Android_Booting
> my questions:
> 1. Any idea where I can find strace for Android (based on Arm CPU)
Just compile it statically with your favorite ARM toolchain. Then push it into 
/data/local/tmp (adb push strace-static-ftw /data/local/tmp; adb shell chmod 
777 /data/local/tmp/strace-static-ftw)

BTW: in this page http://elinux.org/Android_Tools which point here for 
instructions on building:
http://discuz-android.blogspot.co.il/2008/01/create-google-android-strace-tool.html

and here for downloads:
http://benno.id.au/blog/2007/11/18/android-runtime-strace
http://benno.id.au/android/strace

I still recommend compiling your own.

> 2. Can I go into "Console mode" ? In case I fiddle with init*.rc scripts
> and break the OS (for manual recovery of those scripts).
You need a serial console for this, good luck with that.
The "console" you get when you run over adb is running using a limited 
account... but it might be the way for you to "root" the device.

Just for reference, here is how to get a serial console on nexus5:
http://www.abclinuxu.cz/blog/Lorris/2013/12/serial-console-on-google-nexus-5

And this is on Galaxy S4:
http://forum.xda-developers.com/showthread.php?t=1901376

Not trivial!

> 3. The su command (and copies of it that had SUID bit set on it) were
> deleted during boot. Any idea what could have done that?
Do you put it on "/bin" or "/sbin"? Those directories are not mapped to a real 
device, but are part of the initrd. On reboot they are restored. Not a good 
place to save stuff.

I wrote about something similar (Hebrew) a few days/weeks ago. Have a good 
reading: http://cucomania.mooo.com/he/posts/349