Tuesday, December 30, 2014

Make for Android and associated problems

NOTE: Your phone, your responsibility. (all stuff from previous posts)

I managed to compile make for android. But unfortunately it is not foolproof. Download it here and push the contents to the /system folder in the emulator. But there is one slight problem. There is a function that make uses called ttyname(). This function is supposed to be defined in libc. But as android doesn't run on standard libc but bionic. It has not been implemented and left as a stub. It basically returns the name of the terminal device like "/dev/pts/1". I think the best way to get around would be to implement it in bionic stubs code itself. But that would require replacing libc. And I don't like the sound of it. Another way would be to implement it in make. But I wasn't gonna spend this night doing that. So instead i hardcoded it to return "root".

And fortunately enough make seems to work fine without it. I wrote a small makefile and compiled to check. Sorry I did't include that in the package. But have fun trying it out by writing your own.

Let me know if you have any thoughts on implementation of ttyname.

PS: I have made progress on putting the scripts together for build system. Stay tuned 

System image [android-19] with gcc, g++, file and vim

I have uploaded the system image so that you can simply download it and try it out without having to remount or push. Copy the android-19 directory to "system-images" directory of your sdk and create a new avd for android-19 or use the old one doesn't matter. Just remember to close any avds that are open and restart them.

I have also included two source files for hello world, one for C and another for C++. They are there in "/system/bin" directory. Check the system by

Cheers, Have a nice day !!!

Edit: I've also included file and vim binaries, check em out

Monday, December 29, 2014

C C++ programming on Android [added g++ and vim to the package] (ARM specific)

NOTE: Same as old one. If you are dumb enough to spoil your device or emulator (lol), don't blame me. Try at your own risk

For long we have distanced using android as a development machine. This might not be far.

Yesterday, I successfully compiled gcc that could run on android. And today without much delay g++ is here. I've also added vim from my older post. Now you can push all the binaries to the phone and have a nice programming package on phone. I have done a basic sanity test on the binaries and they seem to be working fine. I've also included three sample programs in the bin directory. If possible remove them before pushing to the device. (for details on how to push them to the emulator see my last post)

This system will create binaries that will definitely run on all arm (32 bit) android devices. That means you can compile on your phone and then send it to another phone and it would work (lol, what am I writing. Sorry, sleepy :( ). This will create similar binaries to that of your ndk. So basically all the executables that you could compile with your ndk. Now you can on the phone.

Now to the backsides of it. It takes up large space (around 500 MB). Most of the system partitions are smaller than this so it would require that the partitions be resized and mounted. I could probably make a zip to install but due to this problem it wouldn't work on most devices. You need to edit the system partition size. And I have no idea how to do that, because I don't have an android phone. But if there is anyone willing to do this, please let me know how that turns out.

I've seen a friend of mine try use vim on his phone. And trust me it sucks. We will need a better editor and also a better terminal. For now I would suggest using terminal emulator to try it out. But it will not be as good as a personal computer. I wonder how it will be on a physical keyboard android device. I will search for my old HTC Dream, and hopefully it will work. I also have memory issues on that to be taken care of (half GB extra system storage on HTC Dream, you got to be kidding me). I will let you guys know how that turns out. Meanwhile have fun trying it out.

And ya I almost forgot download it here.

PS: I did try to make a nice build system out of this. But due to my laziness and non-linear working style it has become difficult to put together a script to do the whole build as I initially intended to. But I promise that in near future that I will try and put it up on github or something, after I get it to work. 

Sunday, December 28, 2014

GCC on Android [ARM Specific]

NOTE: I am not responsible for whatever damage you might cause to your emulator or device. You wish to try it out, its by your own will.

Last week, I compiled binutils for android. This week I have another of linux utility for you - "GCC". I haven't fully tested any of these. I've only checked for their sanity. Also owing to the fact that I do not own an android device makes it more problematic. I've only tested it on emulator. I expect it work on devices. I will be more than thankful if anyone can confirm it. The package is very big [around 154 MB zip]. I will probably write how I achieved it some time in future. Unzip the file and copy the contents of the "sysroot" directory to "/system/" in your emulator.You might need to do

adb remount

before that in order to mount the /system/ partition as rw. If you are willing to try in a mobile device.  Open the device prompt by "adb shell" and then

# mount
rootfs / rootfs ro 0 0
tmpfs /dev tmpfs rw,nosuid,mode=755 0 0
devpts /dev/pts devpts rw,mode=600 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
none /acct cgroup rw,cpuacct 0 0
tmpfs /mnt/asec tmpfs rw,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,mode=755,gid=1000 0 0
none /dev/cpuctl cgroup rw,cpu 0 0
/dev/block/mtdblock0 /system yaffs2 rw 0 0
/dev/block/mtdblock1 /data yaffs2 rw,nosuid,nodev 0 0
/dev/block/mtdblock2 /cache yaffs2 rw,nosuid,nodev 0 0

will display the various devices and the mount points. Now you can do remount on "/system" directory. In my case this will be

mount -o remount,rw /dev/block/mtdblock0 /system

Because my system files are contained in "/dev/block/mtdblock0". Now that you have remounted push all the contents of "sysroot" directory to "/system". (Please note that this won't work if you don't have enough space in the system partition. You will need to find a way to increase the space. If you are using an emulator start the emulator with "emulator" binary in sdk "/tools" directory by invoking "./emulator -partition-size 1024 @<avd-name>",  the size of partition can be adjusted to your will. Note that you will need to first create an "avd" for this. Use the GUI in eclipse to do so)

adb push  sysroot/ /system/

[NOTE: This command might not work in all systems. adb push doesn't handle directories. It only works on my macbook. On my ubuntu it doesn't work. If it doesn't work find a better way to handle this or you are stuck copying each of them manually. Or write a script to copy all the contents]

 Now you can use vim that I had previously compiled and posted months ago in conjunction with gcc to create c programs on your mobile and compile them over your device. I could have also included the vim program in the package. I forgot that unfortunately

Somewhere in the bin directory I've included two hello world programs by mistake. one is written in 'c' and the other in assembly. Compile them to test the working of the system.

Above is the output from my adb. And yes I forgot to include a newline character in the hello.c program, get over it.

I expect everything to go fine. There are two versions of toolchain in there, one that produces code for "arm-linux-androideabi" (default one). There is also a second one "arm-none-eabi" this can, in theory be used to produce os independent code like for an arm micro-controller.

I am working on another stupid idea now. I'll let you guys know of when that happens :)

Wednesday, December 17, 2014

Binutils on Android

This is a quick post. I managed to compile binutils to run on android. I have just run a sanity test on them. I am still not sure of its behaviour. But as of now, every thing seems to be running smooth. Once again, I haven't had much time to test it. The assembler seems to be working, I verified it by assembling hello world program on device then pulling it back and linking it with ndk. The compiled program, sure enough spit out "hello, world!". You can download the compiled package here.

I shall keep you posted on the future developments.

PS: Please don't question why the port