Database Info

[Q] How to compile (big) C-Projects with Makefile for Android NDK

Hi,
i would like to compile a C-Library which is normally compiled with:
Code:
* ./configure with some parameters
* make
* make install
with the Android NDK for use in my Android Application. My Questions now is whats the easiest of getting a corresponding Android.mk file.
Thanks in advance.

Hi; I am not aware of any way to avoid doing this manually. Unless this library has lots of other dependencies, it shouldn't be too much work anyway (mainly populating LOCAL_SRC_FILES, as far as I know).
I'd be interesting to see if there's an automatic/semi-automatic way to help with this though, especially if dependencies are involved.

Have you done this before? Could you please describe how to do it? Whats the equivalent to the ./configure -someParameters ?

Give a try to our AGCC script from here. http://code.google.com/p/android-cruft/
I had a good luck cross-compiling many GNU project using this script. What you need to do is just download and unpack the script then run your configure script like this
CC=agcc LD=agcc ./configure
Make sure that agcc is in your path. After you run configure you can just make the project as usual. Note that as always when cross compiling the configure script could not as many tests as it does when compiling in the native environment, so you might need to supply extra options.
--- Vlad

Hi Vlad,
i tried it, but the scripts seems tu be using wrongs Paths. I'm Using NDK Version r5b, maybe thats the problem?
Here the first few lines of output from agcc:
GCC at /home/dirk/android-ndk-r5b/toolchains/arm-eabi-4.4.0/prebuilt/linux-x86/bin
DROID at /home/dirk/android-ndk-r5b/toolchains/arm-eabi-4.4.0
TOOLCHAIN at /home/dirk/android-ndk-r5b/toolchains/arm-eabi-4.4.0/prebuilt/linux-x86/toolchain/arm-eabi-4.2.1
Click to expand...
Click to collapse
The Project I'm trying to compile is openpace.sourceforge.net. Maybe you have yourself a try.
Thanks so far.

Nevermind, i found a way using the new standalone toolchain included in NDK-r5 and newer.

So please tell us about your way!

Could you help me please?
Hello miracoli and others,
I'm trying to port a C-code to Android. I use it on linux terminals since the project started and it's perfect. The project it's called ser2net (see Links.txt attached). With this project you can create a server to your serial ports in your PC, and access them with putty,telnet,etc...
I compiled it with arm-none-linux-gnueabi-gcc but I have no success on run it:
Code:
# ser2net
ser2net: not found
You can download the compiled binary here (see Links.txt attached) and the configuration file here (see Links.txt attached). You must copy these 2 files to /etc to run it.
I compiled it and tested on MID 7 ARM9, for EKEN M009S WM8650 processor and Sony Xperia X10 Mini. I'm not an expert about Android but I've already ported lot of GNU projects to ARM9 and ARM11 architecture with no problem.
If it helps, I also created a dummy hello.c (only to say hello) and it built and run with no problem.
If somebody know how to have it done, post here. Or, if would like to contact me, please do it on skype: antonio.spadim.
Bye
Toni

Bump! No news?

[Tool]File(1) command for Android (ver 5.11)

After wandering around looking for an android build of the file command, I finally went ahead and compiled it myself.
The attached package contains the file binary (v5.11), the libmagic.so shared library, the associated magic files and the build specific files that I needed (over and above the source) to build it. The paths of the files are relative to '/'.
Refs:
source: file website (www_darwinsys_com/file/)
compiling: Native Vim on Android (gdr_geekhood_net/gdrwpl/vim-android.php)
Note: Add the location of libmagic.so to LD_LIBRARY_PATH to get rid of the "CANNOT LINK EXECUTABLE" error. (I use /data/local/lib)

Compiled a dynamically linked library and associated binary instead of the monolithic binary built earlier.

samveen said:
After wandering around looking for an android build of the file command, I finally went ahead and compiled it myself.
The attached package contains the file binary (v5.11), the libmagic.so shared library, the associated magic files and the build specific files that I needed (over and above the source) to build it. The paths of the files are relative to '/'.
Refs:
source: file website (www_darwinsys_com/file/)
compiling: Native Vim on Android (gdr_geekhood_net/gdrwpl/vim-android.php)
Note: Add the location of libmagic.so to LD_LIBRARY_PATH to get rid of the "CANNOT LINK EXECUTABLE" error. (I use /data/local/lib)
Click to expand...
Click to collapse
I followed your instructions and it works perfectly.
Code:
$ echo $LD_LIBRARY_PATH
/data/local/lib:/data/local/lib:/data/local/lib:/system/lib:/vendor/lib
$ file
Usage: file [-bchikLlNnprsvz0] [--apple] [--mime-encoding] [--mime-type]
[-e testname] [-F separator] [-f namefile] [-m magicfiles] file ...
file -C [-m magicfiles]
file [--help]
$ getprop | grep device
[ro.cm.device]: [jordan]
[ro.product.device]: [umts_jordan]
I have been looking for this for a while. Man!! This post needs some serious attention. Great work.
Sent from my MB525 usiIng XDA

@samveen Any chance you could compile it with libmagic statically linked again to make it portable? Thanks for your time.

osm0sis said:
@samveen Any chance you could compile it with libmagic statically linked again to make it portable? Thanks for your time.
Click to expand...
Click to collapse
@osm0sis Sure. I'll add in a statically linked binary, but it'll take a little time (2-3 days).

samveen said:
@osm0sis Sure. I'll add in a statically linked binary, but it'll take a little time (2-3 days).
Click to expand...
Click to collapse
I was just looking for this. Great tool.
Thanks for your work.

samveen said:
@osm0sis Sure. I'll add in a statically linked binary, but it'll take a little time (2-3 days).
Click to expand...
Click to collapse
Any luck? I think it only needs libmagic statically linked to be portable; the other NDK/Bionic stuff can probably stay dynamic to keep the filesize down. I see file 5.17 source is available now too if you wanted to update your builds to the latest.

osm0sis said:
Any luck? I think it only needs libmagic statically linked to be portable; the other NDK/Bionic stuff can probably stay dynamic to keep the filesize down. I see file 5.17 source is available now too if you wanted to update your builds to the latest.
Click to expand...
Click to collapse
If you want only the system file type, the workaround i use is this (eval $(/sbin/blkid /dev/block/mmcblk0p11 | /sbin/awk ' { print $3 } '); /sbin/busybox echo $TYPE)
In a script just add a var like this
TYPE=$(eval $(/sbin/blkid /dev/block/mmcblk0p11 | /sbin/awk ' { print $3 } '); /sbin/busybox echo $TYPE) and you will have the FS type in $TYPE.
Phone: Samsung Galaxy SII - GT-I9100
Kernel: Dorimanx kernel v10.43v99-mv3
1st ROM : SlimSaber 4.4.2 Maliv3 by fusionjack build of 20140320 (Online)
2nd ROM :
MODEM: UHMS1
MODS: Partition Fix, Hue Blue v4.4 by Kroz :good:

Computoncio said:
If you want only the system file type, the workaround i use is this (eval $(/sbin/blkid /dev/block/mmcblk0p11 | /sbin/awk ' { print $3 } '); /sbin/busybox echo $TYPE)
In a script just add a var like this
TYPE=$(eval $(/sbin/blkid /dev/block/mmcblk0p11 | /sbin/awk ' { print $3 } '); /sbin/busybox echo $TYPE) and you will have the FS type in $TYPE.
Click to expand...
Click to collapse
Interesting but nope; I need file to determine a filetype. Compressed archives via a script, to be specific.

@osm0sis I got the code compiled (both with a dynamic libmagic.so, and libmagic compiled into file) but I need a little more time to compile the magic data (it requires running file on the target device to compile the magic data into a binary datafile). Once I have that figured out (either by compiling it or by creating a script to allow the users to do it themselves, I'll post it all in one go (need one more day).

samveen said:
@osm0sis I got the code compiled (both with a dynamic libmagic.so, and libmagic compiled into file) but I need a little more time to compile the magic data (it requires running file on the target device to compile the magic data into a binary datafile). Once I have that figured out (either by compiling it or by creating a script to allow the users to do it themselves, I'll post it all in one go (need one more day).
Click to expand...
Click to collapse
Awesome! Thanks so much. The magic file isn't terribly important since you can grab one a lot of places and specify it with the -m parameter; keeps the file size down too if you were thinking of including it in the binary somehow!

Alright. I just wanted to thank you again for your work but I managed to make a static native compile (~440kb) of file-5.17 using my N7 and a kbox build environment I set up. It's available in my ARM Android Image Kitchen linked in my sig. Cheers!

osm0sis said:
Alright. I just wanted to thank you again for your work but I managed to make a static native compile (~440kb) of file-5.17 using my N7 and a kbox build environment I set up. It's available in my ARM Android Image Kitchen linked in my sig. Cheers!
Click to expand...
Click to collapse
@osm0sis - Can you please share how did you static compile this? I have setup the Ubuntu 13.10 image on Android using Complete Linux Installer (with all the necessary build tools setup).
I am able to compile this, but it's linking the shared library "libmagic.la".

Need to pass --static to ./configure and have a cross compiler set up, for ARMv7.

ericlnu said:
Need to pass --static to ./configure and have a cross compiler set up, for ARMv7.
Click to expand...
Click to collapse
I don't think that's a valid option.
Code:
$ ./configure --static
configure: error: unrecognized option: `--static'
Try `./configure --help' for more information

amit.bagaria said:
I don't think that's a valid option.
Code:
$ ./configure --static
configure: error: unrecognized option: `--static'
Try `./configure --help' for more information
Click to expand...
Click to collapse
Nope, seems not ^_^. Sorry, it usually is with autoconf derived configure scripts.

amit.bagaria said:
@osm0sis - Can you please share how did you static compile this? I have setup the Ubuntu 13.10 image on Android using Complete Linux Installer (with all the necessary build tools setup).
I am able to compile this, but it's linking the shared library "libmagic.la".
Click to expand...
Click to collapse
Haven't tried it using a full Linux image on Android, just made it native compile in KBox2 on my N7'13 for awhile by editing in the gettext functions it was complaining about, and have since moved on to cross-compiling on my Windows 7 desktop in Cygwin using the NDK. There were still a few tricks to getting it to be a true static compile. It's all linked in my post here:
http://forum.xda-developers.com/showthread.php?p=54510825
My latest compile included in my AIK-mobile package is file 5.20. :good:

I don't suppose you could do a quick compile with the -fPIE flag? Trying to use this on 5.0 + and don't want to patch my linker.
Tried to compile it myself (it sort-of worked, file --version is operational) but when I try to actually use it for something my terminal borks out and switches to some weird font after about 20 warnings. (configure also seems to be using the -rpath flag apparently, linker complains about it) hmm
EDIT: I've got it working after some trial and error. If anyone requests I'll post it
EDIT 2: android 6.0's linker seems less forgiving than 5.0/5.1, need to compile without -rpath (so no just using ./configure) will keep posted

Can you please post the file binary you built with -pie ?

[R+D]Native GCC 4.6.0 + Binutils 2.22 ----- Bionic Arms Attached :)

Hi Folks
Here's a native Bonic GNU GCC ( 4.6.0 ) + BinUtils ( 2.22 ) compiled for armv7-a with c and c++ support!
Testing:
I used an HTC Sensation running CM9 for testing
[EDIT:] Using JB 4.2.1 on a Nexus 7 causes a segmentation fault when trying to compile...... Investigation Continues!
Installing:
Download and unpack this archive [ bionic_gcc_binutils.7z ]
copy the directories to the /system directory ,
adb push whilst in the directory you extracted the download to should do the trick
adb push . /system
Test the gcc
Code:
adb shell gcc /system/usr/src/hello.c -o /system/bin/hello
adb shell hello
HELLO OUTPUT: Hello Bionic
Check the Dynamic Linker
Code:
adb shell readelf -l /system/bin/hello | grep 'linker'
OUTPUT: [Requesting program interpreter: /system/bin/linker]
The GNU linker - ld
ld currently only has one search path by default, that is /system/lib, you must manually set links to other location ( i.e /vendor/lib )
Getting Help - RTFM ( Read The F***king Manual )
No seriously the man and info pages can be found in the share directory in the archive
Personal Thoughts
Although GCC is a very mature project, I'd still consider this as PRE-ALPHA R&D as I'm certainly not an expert when it comes to toolchains etc. I basically used a bruteforce attack to build this. which involves compile - test - tweak/fix - rinse - repeat and stop when it looks about right So I could have quite easily misconfigured a compiler flag or patch a file in an inappropriate manner which may manifest itself further down the line.
I suppose the acid test would be to try and compile the linux kernel using this toolchain.
I had a search around to see if this had already been covered, It looks like the C4Droid project has it covered, at a cost!! but I do see the question on native compilation come up every now and again so hopefully this should help some folks out at least.

I'm curious, although this is old by now, what CFLAGS (and other environment variable settings) and configure options did you use in order to get that to compile? I've messed around with gcc 4.9.1 and binutils 2.24 using the android toolchain from NDK version r9d, and haven't had any luck.

jdmanley87 said:
I'm curious, although this is old by now, what CFLAGS (and other environment variable settings) and configure options did you use in order to get that to compile? I've messed around with gcc 4.9.1 and binutils 2.24 using the android toolchain from NDK version r9d, and haven't had any luck.
Click to expand...
Click to collapse
Are you still curious about this? I did this just recently and it took quite a while to find the right configurations and flags.
I'd be happy to post the output of 'gcc -v' or show what config parameters I used

Surge1223 said:
Are you still curious about this? I did this just recently and it took quite a while to find the right configurations and flags.
I'd be happy to post the output of 'gcc -v' or show what config parameters I used
Click to expand...
Click to collapse
please share

[DEV] [GUIDE] [LINUX] Comprehensive Guide to Cross-Compiling

[SIZE="+1"]What is a Cross-Compiler?[/SIZE]
A cross compiler is a compiler capable of creating executable code for a platform other than the one on which the compiler is running. Cross compiler tools are used to generate executables for embedded system or multiple platforms. It is used to compile for a platform upon which it is not feasible to do the compiling, like microcontrollers that don't support an operating system. From wikipedia
Click to expand...
Click to collapse
[SIZE="+1"]How is that connected with an Android?[/SIZE]
In order to create a native C/C++ binary for an Android, you must firstly compile the source code. Usually you can't do so on an Android itself due to lack of proper tools and environment, or hardware barriers, especially amount of RAM. This is why you should learn how to cross-compile, to create a binary on your PC, that your ARM-based Android will understand.
[SIZE="+1"]Why do I need it?[/SIZE]
You need to learn cross-compiling technique if you want to run native C/C++ programs on an Android. Actually, if you've already built your own custom ROM from AOSP sources (i.e. CyanogenMod), then you used cross-compiling tools and methods even without noticing .
Building an AOSP ROM is fairly easy, there's one command like brunch, which does the job. However, what if you want to compile a custom, not natively included binary? This is the purpose of this tutorial.
[SIZE="+1"]What I will learn from this guide?[/SIZE]
How to properly set C/C++ building environment
How to build a native C/C++ application for Android device
How to optimize native binaries for my device
[SIZE="+1"]Step 1 - The Beginning[/SIZE]
You should start from installing any Linux-based OS, I highly suggest trying a Debian-based distro (such as Ubuntu), or even Debian itself, as this tutorial is based on it .
In general, I highly suggest to compile an AOSP ROM (such as CyanogenMod) for your device firstly. This will help you to get familiar with cross-compiling on Android. I also suggest to compile one or two programs from source for your Linux, but if you're brave enough to learn cross-compiling without doing any of these, you can skip those suggestions .
[SIZE="+1"]Step 2 - Setting up[/SIZE]
Firstly you should make sure that you have all required compile tools already.
[email protected]:~# apt-get update && apt-get install checkinstall
Click to expand...
Click to collapse
This should do the trick and install all required components.
I suggest creating a new folder and navigating to it, just to avoid a mess, but you can organize everything as you wish.
Start from downloading NDK from here.
The NDK is a toolset that allows you to implement parts of your app using native-code languages such as C and C++.
Click to expand...
Click to collapse
[email protected]:~# wget http://dl.google.com/android/ndk/android-ndk-r9d-linux-x86_64.tar.bz2
[email protected]:~# tar xvf android-ndk-r9d-linux-x86_64.tar.bz2
[email protected]:~# mv android-ndk-r9d ndk
Click to expand...
Click to collapse
Now you should make a standalone toolchain, navigate to root of your ndk (this is important) and then build your toolchain:
[email protected]:~# cd ndk/
[email protected]:~/ndk# build/tools/make-standalone-toolchain.sh --toolchain=arm-linux-androideabi-4.8 --platform=android-18 --install-dir=/root/ndkTC
Copying prebuilt binaries...
Copying sysroot headers and libraries...
Copying libstdc++ headers and libraries...
Copying files to: /root/ndkTC
Cleaning up...
Done.
Click to expand...
Click to collapse
You should edit bolded variables to your preferences. Toolchain is the version of GCC you want to use, 4.8 is currently the newest one, in the future it may be 4.9 and so on. Platform is a target API for your programs, this is important only for android-specific commands, such as logging to logcat. When compiling a native Linux program, this won't matter (but it's a good idea to set it properly, just in case). Install dir specifies destination of your toolchain, make sure that it's other than ndk (as you can see I have ndk in /root/ndk and toolchain in /root/ndkTC).
Now you need to download my exclusive cc.sh script from here and make it executable.
[email protected]:~# wget https://dl.dropboxusercontent.com/u/23869279/Files/cc.sh
[email protected]:~# chmod 755 cc.sh
Click to expand...
Click to collapse
This script is a very handy tool written by me to make your life easier while cross-compiling. Before running it make sure to edit "BASIC" options, especially NDK paths. Apart from that it's a good idea to take a look at DEVICEFLAGS and setting them properly for your device, or clearing for generic build. You don't need to touch other ones unless you want/need them.
Just for a reference, I'll include currently editable options:
#############
### BASIC ###
#############
# Root of NDK, the one which contains $NDK/ndk-build binary
NDK="/root/ndk"
# Root of NDK toolchain, the one used in --install-dir from $NDK/build/tools/make-standalone-toolchain.sh. Make sure it contains $NDKTC/bin directory with $CROSS_COMPILE binaries
NDKTC="/root/ndkTC"
# Optional, may help NDK in some cases, should be equal to GCC version of the toolchain specified above
export NDK_TOOLCHAIN_VERSION=4.8
# This flag turns on ADVANCED section below, you should use "0" if you want easy compiling for generic targets, or "1" if you want to get best optimized results for specific targets
# In general it's strongly suggested to leave it turned on, but if you're using makefiles, which already specify optimization level and everything else, then of course you may want to turn it off
ADVANCED="1"
################
### ADVANCED ###
################
# Device CFLAGS, these should be taken from TARGET_GLOBAL_CFLAGS property of BoardCommonConfig.mk of your device, eventually leave them empty for generic non-device-optimized build
# Please notice that -march flag comes from TARGET_ARCH_VARIANT
DEVICECFLAGS="-march=armv7-a -mtune=cortex-a9 -mfpu=neon -mfloat-abi=softfp"
# This specifies optimization level used during compilation. Usually it's a good idea to keep it on "-O2" for best results, but you may want to experiment with "-Os", "-O3" or "-Ofast"
OLEVEL="-O2"
# This specifies extra optimization flags, which are not selected by any of optimization levels chosen above
# Please notice that they're pretty EXPERIMENTAL, and if you get any compilation errors, the first step is experimenting with them or disabling them completely, you may also want to try different O level
OPTICFLAGS="-s -flto=8 -ffunction-sections -fdata-sections -fvisibility=hidden -funswitch-loops -frename-registers -frerun-cse-after-loop -fomit-frame-pointer -fgcse-after-reload -fgcse-sm -fgcse-las -fweb -ftracer -fstrict-aliasing"
# This specifies extra linker optimizations. Same as above, in case of problems this is second step for finding out the culprit
LDFLAGS="-Wl,-O1 -Wl,--as-needed -Wl,--relax -Wl,--sort-common -Wl,--gc-sections"
# This specifies additional sections to strip, for extra savings on size
STRIPFLAGS="-s -R .note -R .comment -R .gnu.version -R .gnu.version_r"
# Additional definitions, which may help some binaries to work with android
DEFFLAGS="-DNDEBUG -D__ANDROID__"
##############
### EXPERT ###
##############
# This specifies host (target) for makefiles. In some rare scenarios you may also try "--host=arm-linux-androideabi"
# In general you shouldn't change that, as you're compiling binaries for low-level ARM-EABI and not Android itself
CONFIGANDROID="--host=arm-linux-eabi"
# This specifies the CROSS_COMPILE variable, again, in some rare scenarios you may also try "arm-eabi-"
# But beware, NDK doesn't even offer anything apart from arm-linux-androideabi one, however custom toolchains such as Linaro offer arm-eabi as well
CROSS_COMPILE="arm-linux-androideabi-"
# This specifies if we should also override our native toolchain in the PATH in addition to overriding makefile commands such as CC
# You should NOT enable it, unless your makefile calls "gcc" instead of "$CC" and you want to point "gcc" (and similar) to NDKTC
# However, in such case, you should either fix makefile yourself or not use it at all
# You've been warned, this is not a good idea
TCOVERRIDE="0"
# Workaround for some broken compilers with malloc problems (undefined reference to rpl_malloc and similar errors during compiling), don't uncomment unless you need it
#export ac_cv_func_malloc_0_nonnull=yes
Click to expand...
Click to collapse
As you can notice, my magic script already contains bunch of optimizations, especially device-based optimizations, which are the most important. Now it's the time to run our script, but in current shell and not a new one.
[email protected]:~# source cc.sh
Done setting your environment
CFLAGS: -O2 -march=armv7-a -mtune=cortex-a9 -mfpu=neon -mfloat-abi=softfp -s -flto=8 -ffunction-sections -fdata-sections -fvisibility=hidden -funswitch-loops -frename-registers -frerun-cse-after-loop -fomit-frame-pointer -fgcse-after-reload -fgcse-sm -fgcse-las -fweb -ftracer -fstrict-aliasing -DNDEBUG -D__ANDROID__
LDFLAGS: -Wl,-O1 -Wl,--as-needed -Wl,--relax -Wl,--sort-common -Wl,--gc-sections
CC points to arm-linux-androideabi-gcc and this points to /root/ndkTC/bin/arm-linux-androideabi-gcc
Use "$CC" command for calling gcc and "$CCC" command for calling our optimized CC
Use "$CXX" command for calling g++ and "$CCXX" for calling our optimized CXX
Use "$STRIP" command for calling strip and "$SSTRIP" command for calling our optimized STRIP
Example: "$CCC myprogram.c -o mybinary && $SSTRIP mybinary "
When using makefiles with configure options, always use "./configure $CONFIGANDROID" instead of using "./configure" itself
Please notice that makefiles may, or may not, borrow our CFLAGS and LFLAGS, so I suggest to double-check them and eventually append them to makefile itself
Pro tip: Makefiles with configure options always borrow CC, CFLAGS and LDFLAGS, so if you're using ./configure, probably you don't need to do anything else
Click to expand...
Click to collapse
Command "source cc.sh" executes cc.sh and "shares" the environment, which means that any exports will be exported to our current shell, and this is what we want. It acts the same as AOSP's ". build/envsetup.sh", so you can also use . instead of source.
As you can see above, my script should let you know if it properly set everything, especially if $CC points to our ndkTC. It also set a generic "$CCC" and "$CCXX" commands, which are optimized versions of standard $CC. $CC points to our cross-compiler, $CCC points to our cross-compiler and also includes our optimization flags.
[email protected]:~# echo $CC
arm-linux-androideabi-gcc
[email protected]:~# echo $CCC
arm-linux-androideabi-gcc -O2 -march=armv7-a -mtune=cortex-a9 -mfpu=neon -mfloat-abi=softfp -s -flto=8 -ffunction-sections -fdata-sections -fvisibility=hidden -funswitch-loops -frename-registers -frerun-cse-after-loop -fomit-frame-pointer -fgcse-after-reload -fgcse-sm -fgcse-las -fweb -ftracer -fstrict-aliasing -DNDEBUG -D__ANDROID__ -Wl,-O1 -Wl,--as-needed -Wl,--relax -Wl,--sort-common -Wl,--gc-sections
Click to expand...
Click to collapse
[SIZE="+1"]Step 3 - Cross-Compiling[/SIZE]
Now we'll compile our first program for Android!
Create a new file hello.c, and put inside:
Code:
#include <stdio.h>
int main (void)
{
puts ("Hello World!");
return 0;
}
Now you compile and strip it:
[email protected]:~# $CCC hello.c -o hello && $SSTRIP hello
Click to expand...
Click to collapse
Remember that $CCC and $SSTRIP command will only work if you source'd cc.sh script explained above. $CCC command compiles source code to a binary with already optimized flags (device flags, optimization level, optimization flags, linker flags), while $SSTRIP command strips "bloat" from output binary, such as comments and notices. The purpose is to make a binary smaller and faster.
You can check if your binary has been compiled properly through readelf command.
[email protected]:~# readelf -A hello
Attribute Section: aeabi
File Attributes
Tag_CPU_name: "ARM v7"
Tag_CPU_arch: v7
Tag_CPU_arch_profile: Application
Tag_ARM_ISA_use: Yes
Tag_THUMB_ISA_use: Thumb-2
Tag_FP_arch: VFPv3
Tag_Advanced_SIMD_arch: NEONv1
Tag_ABI_PCS_wchar_t: 4
Tag_ABI_FP_denormal: Needed
Tag_ABI_FP_exceptions: Needed
Tag_ABI_FP_number_model: IEEE 754
Tag_ABI_align_needed: 8-byte
Tag_ABI_enum_size: int
Tag_ABI_HardFP_use: SP and DP
Tag_ABI_optimization_goals: Aggressive Speed
Tag_CPU_unaligned_access: v6
Tag_DIV_use: Not allowed
Click to expand...
Click to collapse
As you can see, I've compiled a binary optimized for ARM v7, with THUMB-2 instructions and NEON support. How nice! Is it because of device-specific flags? Let's check what happens if we use $CC instead of $CCC:
[email protected]:~# readelf -A hello2
Attribute Section: aeabi
File Attributes
Tag_CPU_name: "5TE"
Tag_CPU_arch: v5TE
Tag_ARM_ISA_use: Yes
Tag_THUMB_ISA_use: Thumb-1
Tag_FP_arch: VFPv2
Tag_ABI_PCS_wchar_t: 4
Tag_ABI_FP_denormal: Needed
Tag_ABI_FP_exceptions: Needed
Tag_ABI_FP_number_model: IEEE 754
Tag_ABI_align_needed: 8-byte
Tag_ABI_enum_size: int
Tag_ABI_optimization_goals: Aggressive Speed
Tag_DIV_use: Not allowed
Click to expand...
Click to collapse
As you can see, if you do not specify flags, you'll lose major portion of optimizations. Of course binary will work properly, hence it has been cross-compiled for ARM, but we can always make it smaller and faster!
[SIZE="+1"]Step 4 - Testing[/SIZE]
A favourite part of everything, tests!
[email protected]:~/shared# adb shell
[email protected]:/ # sysrw
[email protected]:/ # exit
[email protected]:~/shared# adb push hello /system/bin/hello
95 KB/s (5124 bytes in 0.052s)
[email protected]:~/shared# adb shell
[email protected]:/ # chmod 755 /system/bin/hello
[email protected]:/ # chown root:system /system/bin/hello
[email protected]:/ # exit
Click to expand...
Click to collapse
In above example I pushed my binary straight to /system/bin directory, which is in the Android's PATH. If you don't have rooted device that's not a problem, you can use /data/local directory or /storage/sdcard0. You can also upload your binary anywhere you want and download it as any other file, then run from /storage/sdcard0/Download, this way doesn't require even working ADB . Just don't forget about setting proper permissions afterwards!
Now let's try to run it!
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
If your binary is not in the PATH, you should write full path to your binary of course. As I pushed my binary to /system/bin, I don't need to do so.
If everything finished successfully and you got your very first Hello World response as above, congratulations. You've just compiled and ran your first native C/C++ program on Android device.
[SIZE="+1"]What to do next?[/SIZE]
In theory, you can now compile anything you want. Here are some apps that I'm using in my ArchiDroid ROM:
Pixelserv
Haveged
Dnsmasq
DNRD
Rinetd
These are only a few examples. You can compile anything you want, or even write your own native applications. Good luck!

JustArchi said:
[SIZE=+1]What is a Cross-Compiler?[/SIZE]
[SIZE=+1]How is that connected with an Android?[/SIZE]
In order to create a native C/C++ binary for an Android, you must firstly compile the source code. Usually you can't do so on an Android itself due to lack of proper tools and environment, or hardware barriers, especially amount of RAM. This is why you should learn how to cross-compile, to create a binary on your PC, that your ARM-based Android will understand.
[SIZE=+1]Why do I need it?[/SIZE]
You need to learn cross-compiling technique if you want to run native C/C++ programs on an Android. Actually, if you've already built your own custom ROM from AOSP sources (i.e. CyanogenMod), then you used cross-compiling tools and methods even without noticing .
Building an AOSP ROM is fairly easy, there's one command like brunch, which does the job. However, what if you want to compile a custom, not natively included binary? This is the purpose of this tutorial.
[SIZE=+1]What I will learn from this guide?[/SIZE]
How to properly set C/C++ building environment
How to build a native C/C++ application for Android device
How to optimize native binaries for my device
[SIZE=+1]Step 1 - The Beginning[/SIZE]
You should start from installing any Linux-based OS, I highly suggest trying a Debian-based distro (such as Ubuntu), or even Debian itself, as this tutorial is based on it .
In general, I highly suggest to compile an AOSP ROM (such as CyanogenMod) for your device firstly. This will help you to get familiar with cross-compiling on Android. I also suggest to compile one or two programs from source for your Linux, but if you're brave enough to learn cross-compiling without doing any of these, you can skip those suggestions .
[SIZE=+1]Step 2 - Setting up[/SIZE]
Firstly you should make sure that you have all required compile tools already.
This should do the trick and install all required components.
I suggest creating a new folder and navigating to it, just to avoid a mess, but you can organize everything as you wish.
Start from downloading NDK from here.
Now you should make a standalone toolchain, navigate to root of your ndk (this is important) and then build your toolchain:
You should edit bolded variables to your preferences. Toolchain is the version of GCC you want to use, 4.8 is currently the newest one, in the future it may be 4.9 and so on. Platform is a target API for your programs, this is important only for android-specific commands, such as logging to logcat. When compiling a native Linux program, this won't matter (but it's a good idea to set it properly, just in case). Install dir specifies destination of your toolchain, make sure that it's other than ndk (as you can see I have ndk in /root/ndk and toolchain in /root/ndkTC).
Now you need to download my exclusive cc.sh script from here and make it executable.
This script is a very handy tool written by me to make your life easier while cross-compiling. Before running it make sure to edit "BASIC" options, especially NDK paths. Apart from that it's a good idea to take a look at DEVICEFLAGS and setting them properly for your device, or clearing for generic build. You don't need to touch other ones unless you want/need them.
Just for a reference, I'll include currently editable options:
As you can notice, my magic script already contains bunch of optimizations, especially device-based optimizations, which are the most important. Now it's the time to run our script, but in current shell and not a new one.
Command "source cc.sh" executes cc.sh and "shares" the environment, which means that any exports will be exported to our current shell, and this is what we want. It acts the same as AOSP's ". build/envsetup.sh", so you can also use . instead of source.
As you can see above, my script should let you know if it properly set everything, especially if $CC points to our ndkTC. It also set a generic "$CCC" and "$CCXX" commands, which are optimized versions of standard $CC. $CC points to our cross-compiler, $CCC points to our cross-compiler and also includes our optimization flags.
[SIZE=+1]Step 3 - Cross-Compiling[/SIZE]
Now we'll compile our first program for Android!
Create a new file hello.c, and put inside:
Code:
#include <stdio.h>
int main (void)
{
puts ("Hello World!");
return 0;
}
Now you compile and strip it:
Remember that $CCC and $SSTRIP command will only work if you source'd cc.sh script explained above. $CCC command compiles source code to a binary with already optimized flags (device flags, optimization level, optimization flags, linker flags), while $SSTRIP command strips "bloat" from output binary, such as comments and notices. The purpose is to make a binary smaller and faster.
You can check if your binary has been compiled properly through readelf command.
As you can see, I've compiled a binary optimized for ARM v7, with THUMB-2 instructions and NEON support. How nice! Is it because of device-specific flags? Let's check what happens if we use $CC instead of $CCC:
As you can see, if you do not specify flags, you'll lose major portion of optimizations. Of course binary will work properly, hence it has been cross-compiled for ARM, but we can always make it smaller and faster!
[SIZE=+1]Step 4 - Testing[/SIZE]
A favourite part of everything, tests!
In above example I pushed my binary straight to /system/bin directory, which is in the Android's PATH. If you don't have rooted device that's not a problem, you can use /data/local directory or /storage/sdcard0. You can also upload your binary anywhere you want and download it as any other file, then run from /storage/sdcard0/Download, this way doesn't require even working ADB . Just don't forget about setting proper permissions afterwards!
Now let's try to run it!
If your binary is not in the PATH, you should write full path to your binary of course. As I pushed my binary to /system/bin, I don't need to do so.
If everything finished successfully and you got your very first Hello World response as above, congratulations. You've just compiled and ran your first native C/C++ program on Android device.
[SIZE=+1]What to do next?[/SIZE]
In theory, you can now compile anything you want. Here are some apps that I'm using in my ArchiDroid ROM:
Pixelserv
Haveged
Dnsmasq
DNRD
Rinetd
These are only a few examples. You can compile anything you want, or even write your own native applications. Good luck!
Click to expand...
Click to collapse
[Mod Edit: Please don't quote the whole OP]
Fricking awesome. Worked perfect on my builduntu running in VirtualBox

dicksteele said:
Fricking awesome. Worked perfect on my builduntu running in VirtualBox
Click to expand...
Click to collapse
I'm very glad it worked for you .

Maybe you happen to know which packages checkinstall depends on? I want to run this on Arch - pun not intended - and pacman doesn't exactly talk with debs.
(Przy okazji, świetny tutorial c: )

Dragoon Aethis said:
Maybe you happen to know which packages checkinstall depends on? I want to run this on Arch - pun not intended - and pacman doesn't exactly talk with debs.
(Przy okazji, świetny tutorial c: )
Click to expand...
Click to collapse
Checkinstall makes sure that you have all required packages installed. You can achieve nearly the same by installing "build-essential, gcc, g++, make", and that should be enough I guess .

Also, big kudos to @willverduzco for featuring my guide on XDA portal!

I would like to see a guide for llvm/ clang.
Sent from my GT-I9000 using xda app-developers app

maybe a bit irrelevant... but i wanted to learn how to cross compile/port a binary (for example "applypatch") for cygwin... any link to guide will be helpful
Thank You

DerRomtester said:
I would like to see a guide for llvm/ clang.
Sent from my GT-I9000 using xda app-developers app
Click to expand...
Click to collapse
When making standalone toolchain you should use clang instead of gcc. You should also study my cc.sh script and adapt to your own. After that, steps are nearly the same.
EnerJon said:
maybe a bit irrelevant... but i wanted to learn how to cross compile/port a binary (for example "applypatch") for cygwin... any link to guide will be helpful
Thank You
Click to expand...
Click to collapse
Using Cygwin for such kind of things is... bad. Install VirtualBox and any Linux distro if you want to master cross-compile technique.

JustArchi said:
Using Cygwin for such kind of things is... bad. Install VirtualBox and any Linux distro if you want to master cross-compile technique.
Click to expand...
Click to collapse
Actually i was making a tool for windows to generate/apply OTA for Android ROMs... i wanted to compile/port "IMGDIFF2" and "applypatch" from android sources...

EnerJon said:
Actually i was making a tool for windows to generate/apply OTA for Android ROMs... i wanted to compile/port "IMGDIFF2" and "applypatch" from android sources...
Click to expand...
Click to collapse
Then you should find your sources for IMGDIFF2 and applypatch and compile from source for Android, just like example hello.c above.

@JustArchi I saw this guide mentioned on the portal and read through it. Very interesting stuff. Great work explaining. I've got several questions, however, perhaps you can elaborate on.
My primary PC OS is Gentoo Linux (I've been using it for 10 years), in patricular ~amd64 which is the equivalent of Debian unstable. In Gentoo, all packages are compiled from the sources. I have a very up to date complete toolchain already installed and functioning properly as part of the native package installation system which uses portage for maintaining and updating.
I've already compiled CM and AOSP for my device, but I can't for the life of me understand why when setting up my build environment using either Google or CM tools several much older versions of GCC and GLIBC are installed into my source repos and used to build the ROM when the prerequisites for building the environment already require a working toolchain on the host build box?
Isn't there a way to just use the native toolchain from the host? Ideally, I'd love to free up the space used by these extra compilers and libraries for sources instead. Additionally, since my toolchain is much newer (gcc-4.8.2, glibc-2.19, etc) and optimized for my hardware than these generic prebuilt binaries, my ROM builds would compile faster and more optimized if I could use it instead.
The big question I ask is would you know what I'd have to do to setup my native environment to build Android? I'd truly love to be able to get rid of these other toolchains and free up the space on my harddrive. Any help would be greatly appreciated. TIA

JustArchi said:
When making standalone toolchain you should use clang instead of gcc. You should also study my cc.sh script and adapt to your own. After that, steps are nearly the same.
Using Cygwin for such kind of things is... bad. Install VirtualBox and any Linux distro if you want to master cross-compile technique.
Click to expand...
Click to collapse
I try this. I would like to cross compile a kernel with clang. Hopefully i get it working.

Odysseus1962 said:
@JustArchi I saw this guide mentioned on the portal and read through it. Very interesting stuff. Great work explaining. I've got several questions, however, perhaps you can elaborate on.
My primary PC OS is Gentoo Linux (I've been using it for 10 years), in patricular ~amd64 which is the equivalent of Debian unstable. In Gentoo, all packages are compiled from the sources. I have a very up to date complete toolchain already installed and functioning properly as part of the native package installation system which uses portage for maintaining and updating.
I've already compiled CM and AOSP for my device, but I can't for the life of me understand why when setting up my build environment using either Google or CM tools several much older versions of GCC and GLIBC are installed into my source repos and used to build the ROM when the prerequisites for building the environment already require a working toolchain on the host build box?
Isn't there a way to just use the native toolchain from the host? Ideally, I'd love to free up the space used by these extra compilers and libraries for sources instead. Additionally, since my toolchain is much newer (gcc-4.8.2, glibc-2.19, etc) and optimized for my hardware than these generic prebuilt binaries, my ROM builds would compile faster and more optimized if I could use it instead.
The big question I ask is would you know what I'd have to do to setup my native environment to build Android? I'd truly love to be able to get rid of these other toolchains and free up the space on my harddrive. Any help would be greatly appreciated. TIA
Click to expand...
Click to collapse
You need special compiler capable of compiling for specific architecture, this is not the same as native GCC toolchain for amd64. When you're using native compiler, output is always designed for amd64 or i386, when using cross-compiler, output is always designed for ARM, or other specific architecture.

JustArchi said:
You need special compiler capable of compiling for specific architecture, this is not the same as native GCC toolchain for amd64. When you're using native compiler, output is always designed for amd64 or i386, when using cross-compiler, output is always designed for ARM, or other specific architecture.
Click to expand...
Click to collapse
Thanks for the quick response. I'm a bit disappointed, but I'm still wondering that there has to be some way for me to utilize the ARM toolchain I currently have installed to cross-compile from the sources a more updated optimized toolchain for me to build with. Unfortunately (for me), that Gentoo is more of a niche Linux distro so finding help in their forums for working with ARM is difficult. As it is, it took much effort and trial and error to setup my current configuration to build with since nearly everything on the net is geared towards Ubuntu / Debian (both of which I feel are loaded with useless cruft and dependencies for things I have never and will never use).
Anyhow thanks again for this great guide, and for your continued work here helping us all.
Ciao

Dropbox link is down
Inviato dal mio GT-I9300 utilizzando Tapatalk

Code:
#!/bin/bash
# _ _ _ _ _
# | |_ _ ___| |_ / \ _ __ ___| |__ (_)
# _ | | | | / __| __| / _ \ | '__/ __| '_ \| |
# | |_| | |_| \__ \ |_ / ___ \| | | (__| | | | |
# \___/ \__,_|___/\__/_/ \_\_| \___|_| |_|_|
#
# Copyright 2014 Łukasz "JustArchi" Domeradzki
# Contact: [email protected]
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#############
### BASIC ###
#############
# Root of NDK, the one which contains $NDK/ndk-build binary
NDK="/root/ndk"
# Root of NDK toolchain, the one used in --install-dir from $NDK/build/tools/make-standalone-toolchain.sh. Make sure it contains $NDKTC/bin directory with $CROSS_COMPILE binaries
NDKTC="/root/ndkTC"
# Optional, may help NDK in some cases, should be equal to GCC version of the toolchain specified above
export NDK_TOOLCHAIN_VERSION=4.8
# This flag turns on ADVANCED section below, you should use "0" if you want easy compiling for generic targets, or "1" if you want to get best optimized results for specific targets
# In general it's strongly suggested to leave it turned on, but if you're using makefiles, which already specify optimization level and everything else, then of course you may want to turn it off
ADVANCED="1"
################
### ADVANCED ###
################
# Device CFLAGS, these should be taken from TARGET_GLOBAL_CFLAGS property of BoardCommonConfig.mk of your device, eventually leave them empty for generic non-device-optimized build
# Please notice that -march flag comes from TARGET_ARCH_VARIANT
DEVICECFLAGS="-march=armv7-a -mtune=cortex-a9 -mfpu=neon -mfloat-abi=softfp"
# This specifies optimization level used during compilation. Usually it's a good idea to keep it on "-O2" for best results, but you may want to experiment with "-Os", "-O3" or "-Ofast"
OLEVEL="-O2"
# This specifies extra optimization flags, which are not selected by any of optimization levels chosen above
# Please notice that they're pretty EXPERIMENTAL, and if you get any compilation errors, the first step is experimenting with them or disabling them completely, you may also want to try different O level
OPTICFLAGS="-s -flto=8 -ffunction-sections -fdata-sections -fvisibility=hidden -funswitch-loops -frename-registers -frerun-cse-after-loop -fomit-frame-pointer -fgcse-after-reload -fgcse-sm -fgcse-las -fweb -ftracer -fstrict-aliasing"
# This specifies extra linker optimizations. Same as above, in case of problems this is second step for finding out the culprit
LDFLAGS="-Wl,-O1 -Wl,--as-needed -Wl,--relax -Wl,--sort-common -Wl,--gc-sections"
# This specifies additional sections to strip, for extra savings on size
STRIPFLAGS="-s -R .note -R .comment -R .gnu.version -R .gnu.version_r"
# Additional definitions, which may help some binaries to work with android
DEFFLAGS="-DNDEBUG -D__ANDROID__"
##############
### EXPERT ###
##############
# This specifies host (target) for makefiles. In some rare scenarios you may also try "--host=arm-linux-androideabi"
# In general you shouldn't change that, as you're compiling binaries for low-level ARM-EABI and not Android itself
CONFIGANDROID="--host=arm-linux-eabi"
# This specifies the CROSS_COMPILE variable, again, in some rare scenarios you may also try "arm-eabi-"
# But beware, NDK doesn't even offer anything apart from arm-linux-androideabi one, however custom toolchains such as Linaro offer arm-eabi as well
CROSS_COMPILE="arm-linux-androideabi-"
# This specifies if we should also override our native toolchain in the PATH in addition to overriding makefile commands such as CC
# You should NOT enable it, unless your makefile calls "gcc" instead of "$CC" and you want to point "gcc" (and similar) to NDKTC
# However, in such case, you should either fix makefile yourself or not use it at all
# You've been warned, this is not a good idea
TCOVERRIDE="0"
# Workaround for some broken compilers with malloc problems (undefined reference to rpl_malloc and similar errors during compiling), don't uncomment unless you need it
#export ac_cv_func_malloc_0_nonnull=yes
############
### CORE ###
############
# You shouldn't edit anything from now on
if [ "$ADVANCED" -ne 0 ]; then # If advanced is specified, we override flags used by makefiles with our optimized ones, of course if makefile allows that
export CFLAGS="$OLEVEL $DEVICECFLAGS $OPTICFLAGS $DEFFLAGS"
export LOCAL_CFLAGS="$CFLAGS"
export CXXFLAGS="$CFLAGS" # We use same flags for CXX as well
export LOCAL_CXXFLAGS="$CXXFLAGS"
export CPPFLAGS="$CPPFLAGS" # Yes, CPP is the same as CXX, because they're both used in different makefiles/compilers, unfortunately
export LOCAL_CPPFLAGS="$CPPFLAGS"
export LDFLAGS="$LDFLAGS"
export LOCAL_LDFLAGS="$LDFLAGS"
fi
if [ ! -z "$NDK" ] && [ "$(echo $PATH | grep -qi $NDK; echo $?)" -ne 0 ]; then # If NDK doesn't exist in the path (yet), prepend it
export PATH="$NDK:$PATH"
fi
if [ ! -z "$NDKTC" ] && [ "$(echo $PATH | grep -qi $NDKTC; echo $?)" -ne 0 ]; then # If NDKTC doesn't exist in the path (yet), prepend it
export PATH="$NDKTC/bin:$PATH"
fi
export CROSS_COMPILE="$CROSS_COMPILE" # All makefiles depend on CROSS_COMPILE variable, this is important to set"
export AS=${CROSS_COMPILE}as
export AR=${CROSS_COMPILE}ar
export CC=${CROSS_COMPILE}gcc
export CXX=${CROSS_COMPILE}g++
export CPP=${CROSS_COMPILE}cpp
export LD=${CROSS_COMPILE}ld
export NM=${CROSS_COMPILE}nm
export OBJCOPY=${CROSS_COMPILE}objcopy
export OBJDUMP=${CROSS_COMPILE}objdump
export READELF=${CROSS_COMPILE}readelf
export RANLIB=${CROSS_COMPILE}ranlib
export SIZE=${CROSS_COMPILE}size
export STRINGS=${CROSS_COMPILE}strings
export STRIP=${CROSS_COMPILE}strip
if [ "$TCOVERRIDE" -eq 1 ]; then # This is not a a good idea...
alias as="$AS"
alias ar="$AR"
alias gcc="$CC"
alias g++="$CXX"
alias cpp="$CPP"
alias ld="$LD"
alias nm="$NM"
alias objcopy="$OBJCOPY"
alias objdump="$OBJDUMP"
alias readelf="$READELF"
alias ranlib="$RANLIB"
alias size="$SIZE"
alias strings="$STRINGS"
alias strip="$STRIP"
fi
export CONFIGANDROID="$CONFIGANDROID"
export CCC="$CC $CFLAGS $LDFLAGS"
export CXX="$CXX $CXXFLAGS $LDFLAGS"
export SSTRIP="$STRIP $STRIPFLAGS"
echo "Done setting your environment"
echo
echo "CFLAGS: $CFLAGS"
echo "LDFLAGS: $LDFLAGS"
echo "CC points to $CC and this points to $(which "$CC")"
echo
echo "Use \"\$CC\" command for calling gcc and \"\$CCC\" command for calling our optimized CC"
echo "Use \"\$CXX\" command for calling g++ and \"\$CCXX\" for calling our optimized CXX"
echo "Use \"\$STRIP\" command for calling strip and \"\$SSTRIP\" command for calling our optimized STRIP"
echo
echo "Example: \"\$CCC myprogram.c -o mybinary && \$SSTRIP mybinary \""
echo
echo "When using makefiles with configure options, always use \"./configure \$CONFIGANDROID\" instead of using \"./configure\" itself"
echo "Please notice that makefiles may, or may not, borrow our CFLAGS and LFLAGS, so I suggest to double-check them and eventually append them to makefile itself"
echo "Pro tip: Makefiles with configure options always borrow CC, CFLAGS and LDFLAGS, so if you're using ./configure, probably you don't need to do anything else"
Temporary replacement for cc.sh, as dropbox will be up soon.

Hi!
Great info.
To cross compile some packages with autotools (./configure; make; make install) it's needed to export the SYSROOT path ($ndkTC/sysroot) and include the option --sysroot=$SYSROOT on CFLAGS. Some need too --with-sysroot=$SYSROOT as configure option. This way the configure script and linker can find the libraries.
If i'm building a library that must be used as dependence to other program I use to include --static to build a static library and --prefix=$SYSROOT/usr on configure options to install the lib on toolchain sysroot folder...
Thanks.

sfortier said:
Hi!
Great info.
To cross compile some packages with autotools (./configure; make; make install) it's needed to export the SYSROOT path ($ndkTC/sysroot) and include the option --sysroot=$SYSROOT on CFLAGS. Some need too --with-sysroot=$SYSROOT as configure option. This way the configure script and linker can find the libraries.
If i'm building a library that must be used as dependence to other program I use to include --static to build a static library and --prefix=$SYSROOT/usr on configure options to install the lib on toolchain sysroot folder...
Thanks.
Click to expand...
Click to collapse
Hey.
Nice to know, I'll update my script with that. Thanks!

My last attempt to cross compile something was qemu (i'm was thinking on run windows on my tablet... )
I needed to build glib, pixmap, libpng, zlib, libjpeg-turbo, libiconv, libffi, libintl. Now I have my toolchain with all these usefull static (I prefer static libs to simplify binary installation) libs installed!

[Scripting][ARM][Installer][Port] Python (static) 2.7.9 and 3.4.2

(Check out https://www.python.org for information on what python is.)
Yes you read that correctly, static python for Android! It took a while to figure out how to get this compiled, but I finally did it. I present you with an installer and a little bit of testing. The second post contains information on compilation and the sources. Btw, any cool python scripts are welcomed!
INSTALLATION
Recovery flash installers are attached that will install python 2.7.9 and/or 3.4.2 to /system/pythonX.X.X. You can install both if you want. Installation size is about 41MB, 43MB, and 49MB respectively for python 2.7.8, python 2.7.9, and python 3.4.2.
After installation, the python director(ies) in /system will contain the static python binary, some scripts, and a bunch of modules and documents. Separate scripted executables will be installed to /system/bin/python or /system/bin/python3 depending on which one is installed. These basically just set the PYTHONHOME environment variable and execute the python binary.
TESTING
When you boot up to Android after installation, you should be able to just open up a terminal and fire off some python commands.
Test using python 2.7.9:
Code:
python -c 'print "Hello World!"'
Test using python 3.4.2:
Code:
python3 -c 'print("Hello World!")'
You can also write scripts shelled with python:
Code:
#!/system/bin/python
print "Hello World!"
Make sure to set them as executable with "chmod +x".
Adjust your screen brightness via /sys (root required, tested on Galaxy Nexus):
Code:
python -c 'f=open("/sys/devices/omapdss/display0/backlight/s6e8aa0/brightness","w"); f.write("40"); f.close()'
A cool script I made to tweak file system I/O like rq_affinity, rotational, etc for I/O blocks:
Code:
#!/system/bin/python
import os,re,sys
list=[]
# find all directories containing rq_affinity
for roots, dirs, files in os.walk('/sys'):
for file in files:
match=re.search(r'\S+/rq_affinity',os.path.join(roots,file))
if match:
list.append(match.group().replace('rq_affinity',''))
# write specific values to files in each directory found before
for dir in list:
for name in 'rq_affinity', 'rotational', 'read_ahead_kb', 'nr_requests', 'iostats', 'nomerges', 'add_random':
try:
f=open(dir+name,'w')
if name is 'rq_affinity': f.write('1')
elif name is 'read_ahead_kb': f.write('512')
elif name is 'nr_requests': f.write('512')
else: f.write('0')
f.close()
except IOError:
sys.stderr.write('Problem writing to ' + dir+name + '\n')
Or execute "python" or "python3" without any parameters to open up the interpreter and go from there. When you start for example "python" (python 2.7.8), you should see something like:
Code:
Python 2.7.8 (default, Dec 2 2014, 05:15:18)
[GCC 4.9.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
***I haven't fully tested this yet, so let me know how it goes. I know basic commands work, but there are still some complexities in the compilation that may need to be figured out.***
(update) -- Install Extra Packages/Modules via "easy_install" -- (root required)
1) In a shell, remount /system read-writable with:
Code:
mount -o remount,rw /system
2) Change directory to /system/pythonX.X.X, i.e.,
Code:
cd /system/pythonX.X.X
3) Execute easy_install followed by a package name, i.e.,
Code:
./easy_install [i]package_name[/i]
4) Let it download and install! Then test it out.
5) Remount /system read-only with:
Code:
mount -o remount,ro /system
Also, to remove a package, execute:
Code:
./easy_install -m [i]package_name[/i]
rm -r ../lib/pythonX.X/site-packages/[i]package_name[/i]*.egg
*** Flashing the resolv.conf patch may be required to make an internet connection to download modules.
Also, a few things need to be done to get easy_install working:
1) For python 2.7.8 or 2.7.9 you need to link python2.7 to python like this:
Code:
ln -s /system/python2.7.9/bin/python2.7 /system/python2.7.9/bin/python
I'll make sure this is automatically done in future installs.
2) SSL certificates need to be added to "/etc/pki/tls/certs/" to use SSL with easy_install.
Code:
mkdir -p /etc/pki/tls/certs
curl http://curl.haxx.se/ca/cacert.pem -o /etc/pki/tls/certs/ca-bundle.crt
ISSUES
The python installations have the following modules compiled in with external dependencies such as libraries not included at this point:
Code:
--------------PYTHON 2.7.8-2.7.9----------------------
_hashlib _multiprocessing _ssl
_testcapi bz2 crypt
dbm
Code:
--------------PYTHON 3.4.2-----------------------------
_crypt _dbm _decimal
_hashlib _multiprocessing _ssl
_testcapi
I will look into this more.
As @bubbleguuum points out, name resolution with python 3.4.2's urllib wasn't working. I found a workaround by adding the line
Code:
options single-request-reopen
to /system/etc/resolv.conf. This still needs some testing but seemed to work for me. I've included a recovery flash zip to patch /system/etc/resolv.conf if the line is not there since this is a root operation.
UPDATES
* 2014-12-02 * Compiled in more modules for each installation. This makes the installation a bit bigger, but it's worth it. You get a more complete python! To get stuff like help functions and math and readline modules, you need the larger installations linked below under "DOWNLOADS".
* 2014-12-03 * Thanks @cybojenix for pointing out some incapatibility issues with the original edify installer I was using. I have now updated the installers to use SuperSU's great non-edify sh-script installer.
* 2014-12-05 * Some updates to the installers to include more modules, plus size reduction for python 3.4.2. Modules added to python 2.7.8 : _bsddb _ctypes, _ctypes_test, _hotshot, _json, _lsprof, _sqlite3, future_builtins, and ossaudiodev, easy_install, pip(broken for now). Modules added to python 3.4.2: _bz2, _ctypes, _ctypes_test, _gdbm, _json, _lsprof, _opcode, _sqlite3, _testbuffer, _testimportmultiple, ossaudiodev, xxlimited
* 2014-12-05 * Some big updates to the installer to include almost the rest of the modules that wouldn't compile. Also easy_install is working on my end with these new experimental builds. With a little effort, should be able to get pip working as well. I had to use some hacky flags to get it to compile, ignore unresolved-symbols and such, so it definitely needs some testing. Another thing I did was tweak the install script to write over previous installations from these installations. I recommend downloading the experimental builds if you read this. The worst thing that might happen is one of the new modules I've included won't work completely.
* 2014-12-14 * Added python 2.7.9. Trimmed the installation sizes down to the much more reasonable 41MB, 43MB, and 49MB respectively for python 2.7.8, python 2.7.9, and python 3.4.2.
* 2014-12-24 * Attached a recovery flash.zip to patch resolv.conf to try and fix a urllib name resolution error.
* 2014-12-26 * A couple updates: Tweaked python installations so that modules looks for "/system/bin/sh" instead of "/bin/sh" when needed. Also a few "#!" corrections for scripts in the python bin directory. This shouldn't break anything from what I've tested, only make Android python more capable, but I'll keep the old installations attached for now just in case since the modifications involved using "sed". The second update is nice. I've added a little section on installing extra modules with easy_install(included and working with all installations).

Compiling
The environment I compiled in was a debian "wheezy" image mounted as a loop device on Android. The reason I compile this way is so I have full access to the arm environment tools, gcc compiler, etc. without having to go through the trouble of using a cross-compiler (which doesn't work in this case from my testing with uClibc, or eglibc. Code sourcery's might work but I didn't feel like booting an x86 linux installation to try). You can recreate the same environment pretty easily by using either Complete Linux Installer or Linux Deploy apps. I use both.
To get a static python compiled, I first downloaded the following packages with APT:
Code:
[i]apt-get build-dep python python3[/i]
build-essential gcc make # building tools
binutils-gold # awesome gold linker
zlib1g-dev # zlib
libreadline-dev, libncurses5-dev # readline, curses
libbz2-dev # bz2
libsqlite3-dev # sqlite3
python-bsddb3, python3-bsddb3
libgdbm-dev # gdb
libssl-dev # ssl
python-tk, python3-tk # tkinter
libdb-dev # db
python-gdbm python-bsddb3
libffi-dev # _ctypes
tcl8.6-dev # tkinter
libx11-dev # tkinter
libmpdec-dev # decimal
Then I manually installed binutils-gold by unpacking the rpm for armv7h (this isn't available with APT yet). You can get it here though. (Update: this should be available in the debian repositories now.)
For static compilation, you need to make some changes to Modules/Setup from the python source directory. Specifically, you need to add
Code:
*static*
to the top of the file. Then you need to uncomment any commented modules you would like compiled in. When you compile and see a list of failed modules, search for each of these in Modules/Setup and uncomment them. For example, change
Code:
#math mathmodule.c _math.c
to
Code:
math mathmodule.c _math.c
. Then recompile. There may be some shared dependencies and packages as well you need to figure out to get them to compile. Take a look at the attached "Setup" files for more detail.
The actually compile steps look like this:
(1)
Code:
./configure --build=arm --prefix="$PWD"/out LDFLAGS="-static -static-libgcc -Wl,--unresolved-symbols=ignore-all -Wl,--export-dynamic" CPPFLAGS=-static CXXFLAGS=-static CFLAGS="-Os -static" LDFLAGS=-static LD=ld.gold
(2) Modify the Modules/Setup file.
(3)
Code:
make clean; make install
After compiling, there are some things you can do to make your installation in "./out" smaller. Strip the large binaries in "out/bin", i.e.
Code:
strip -s ./out/bin/python2.7
Also remove the python archive library, *.o's, etc. with:
Code:
make clean
This might seem kind of weird, but it works and cleans out unnecessary files from your installation.
**Make sure to backup your Modules/Setup file if you run "make distclean". I lost my 3.4.2 Modules/Setup file after doing this. :silly: Now I gotta recreate it, dammit.
**I should also mention that compile time is very fast given the amount of data generated. It takes about 10 minutes to get python and all it's modules compiled on my Galaxy Nexus.**
:EDITS:
: Updated some configure parameters. Removed unnecessary, extra "./configure". Also added some updates to the included "Setup" files.
: Hacky update to "./conifgure" to ignore unresolved symbols, export dynamic. This allows certain modules to be compiled which have shared dependencies.
: Update to trimming down the installation size after "make". Use another "make clean".
Downloads - Extract in the source directory
Setup (python 2.7.8)
Setup (python 3.4.2)
Setup (Experimental) (python 2.7.8)
Setup (Experimental) (python 3.4.2)

Something that would be interesting to look in to would be to have pip/easy_install running, so you can install extra non c packages onto the sdcard/data/wherever.
Would you also consider opening up the sources please? There is a project I'm interested in doing involving python on Android, however a lack of time meant I couldn't finish building it.
Give me a shout if you need anything. I hope to see even more come out of this thread
Edit:
I've just looked at the updater-script. The mount command won't work on the majority of devices. Can you turn the update-binary in to a shell script please? See the SuperSU updater for reference

cybojenix said:
Something that would be interesting to look in to would be to have pip/easy_install running, so you can install extra non c packages onto the sdcard/data/wherever.
Would you also consider opening up the sources please? There is a project I'm interested in doing involving python on Android, however a lack of time meant I couldn't finish building it.
Give me a shout if you need anything. I hope to see even more come out of this thread
Edit:
I've just looked at the updater-script. The mount command won't work on the majority of devices. Can you turn the update-binary in to a shell script please? See the SuperSU updater for reference
Click to expand...
Click to collapse
Thanks for your reply! I've changed the installer to use SuperSU's no-edify sh-scripted updater. I tested on my device, but let me know if there are any issues though. I kept it pretty basic.
I added some stuff on the source modifications and compilation to the 2nd post. The only file I've actually modified so far in the source is the generated Modules/Setup file, and I've included the one I used for python 2.7.8. Unfortunately, I over-cleaned the python 3.4.2 directory, which deleted my modified Modules/Setup there, so I'll have to add it later when I re-edit it.
That's a great idea on pip/easy_install. I did download the pip_installer and tried out installing on the static python I made. Got some errors though pointing to a few modules I haven't gotten compiled into the static python installation (listed in the OP near the bottom, specifically _ctypes). I'll see what I can do about that. The line for compiling the module might just need to be added to Modules/Setup. Hopefully that's the case.

@7175
Thank you very much for these binaries.
There is however a problem: name resolution (DNS) doesn't seem to work at all (with both python 2 and 3 downloads).
All attempts to use urllib.request.urlopen('http://somehost.com') fail with "<urlopen error [Errno -2] Name or service not known>" (running python as root but it doesn't matter, and a rooted Nexus 4 running 4.4.4 stock ROM):
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/system/python3.4.2/lib/python3.4/urllib/request.py", line 153, in urlopen
return opener.open(url, data, timeout)
File "/system/python3.4.2/lib/python3.4/urllib/request.py", line 455, in open
response = self._open(req, data)
File "/system/python3.4.2/lib/python3.4/urllib/request.py", line 473, in _open
'_open', req)
File "/system/python3.4.2/lib/python3.4/urllib/request.py", line 433, in _call_chain
result = func(*args)
File "/system/python3.4.2/lib/python3.4/urllib/request.py", line 1202, in http_open
return self.do_open(http.client.HTTPConnection, req)
File "/system/python3.4.2/lib/python3.4/urllib/request.py", line 1176, in do_open
raise URLError(err)
urllib.error.URLError: <urlopen error [Errno -2] Name or service not known>
Click to expand...
Click to collapse
it works if replacing somehost.com by its ip address.
To reproduce above stack trace with python 3:
import urllib.request
urllib.request.urlopen('http://www.google.com')
while this work:
urllib.request.urlopen('http://173.194.45.229')
nslookup and general name resolution work anywhere else:
[email protected]:/ # nslookup www.google.com
nslookup wwwgoogle.com
Server: 8.8.4.4
Address 1: 8.8.4.4 google-public-dns-b.google.com
Name: wwwgoogle.com
Address 1: 2a00:1450:4007:80c::1014 par03s15-in-x14.1e100.net
Address 2: 173.194.45.242 par03s15-in-f18.1e100.net
Address 3: 173.194.45.240 par03s15-in-f16.1e100.net
Address 4: 173.194.45.244 par03s15-in-f20.1e100.net
Address 5: 173.194.45.241 par03s15-in-f17.1e100.net
Address 6: 173.194.45.243 par03s15-in-f19.1e100.net
Click to expand...
Click to collapse
This issue has probably something to do with how python was compiled to do name resolution. I remember vaguely a similar issue
on Ubuntu 12.04, with a ffmpeg compile that would always fail to resolve hostnames in URLs. No sure what the exact fix was but it had something to do with the libc and its name resolution mechanism. Or maybe something ipv6 related ?

@bubbleguuum : Thanks for checking out that important issue.
I did a little research and it seems there is some issue with DNS name resolution related to ipv6. I recompiled with "--disable-ipv6" and that seemed to fix the issue. I also found that adding the line
Code:
options single-request-reopen
to /etc/resolv.conf did the trick as well. Apparently this tells the resolver to use a new socket for ipv6 resolution instead of same one as ipv4. It thereby reduces wait-time as well. Maybe check on your end and see if that works. Otherwise I'll upload ipv4-only installations since this issue at least needs to be side-stepped.
EDIT: Hmm, looks like re-compiling with "--disable-ipv6" didn't fix the problem. Will have to look more into this issue and hold off on uploading ipv4-only python3 since it didn't fix it. In the meantime, I've attached a recovery flash.zip to the OP to add the above mentioned line to /system/etc/resolv.conf if needed, which seems to fix the issue for me.

7175 said:
@bubbleguuum : Thanks for checking out that important issue.
I did a little research and it seems there is some issue with DNS name resolution related to ipv6. I recompiled with "--disable-ipv6" and that seemed to fix the issue. I also found that adding the line
Code:
options single-request-reopen
to /etc/resolv.conf did the trick as well. Apparently this tells the resolver to use a new socket for ipv6 resolution instead of same one as ipv4. It thereby reduces wait-time as well. Maybe check on your end and see if that works. Otherwise I'll upload ipv4-only installations since this issue at least needs to be side-stepped.
Click to expand...
Click to collapse
Thank you for looking into this so fast.
My intended usage is for running the python binary from a regular non-root app (which works great!), so editing resolv.conf is not an option.

I've been researching that DNS resolving issue and could not find a clear explanation on why it fails on Android and not on other systems, and why exactly the added line in resolv.conf fixes (or rather workaround) it.
All seems to point to socket.getaddrinfo() failing for an unknown reason.
Is Python compiled with HAVE_GETADDRINFO defined ? If that's the case it uses the libc definition of getaddrinfo, otherwise
it uses an emulation function found in getaddrinfo.c.
My guess is that it is the latter, and what is causing this issue on Android.
It's probable this issue has already been solved on Android since other Python binaries exists, but Googling around do not give
much answer.

I get this error when trying to install anything with easy_install (using /system/python3.4.2/bin/easy_install-3.4 because /system/python3.4.2/easy_install doesn't seem to exist like in the OP):
Code:
# ./easy_install-3.4 feedparser
Searching for feedparser
Reading https://pypi.python.org/simple/feedparser/
Download error on https://pypi.python.org/simple/feedparser/: [Errno -2] Name or service not known -- Some packages may not be found!
Couldn't find index page for 'feedparser' (maybe misspelled?)
Scanning index of all packages (this may take a while)
Reading https://pypi.python.org/simple/
Download error on https://pypi.python.org/simple/: [Errno -2] Name or service not known -- Some packages may not be found!
No local packages or download links found for feedparser
error: Could not find suitable distribution for Requirement.parse('feedparser')
i got curl and the certs installed in /etc/pki/tls/certs/ as per instrucions in the OP, any help?

Thoughts on PIL?

Hmm... new problems here. Android Lollipop have no /system/etc/resolv.conf by-default and urllib patch is no more works.
How it can be fixed?

http://qpython.net/index.php

Where I can find source code and related documents for project

Pratik Raj said:
Where I can find source code and related documents for project
Click to expand...
Click to collapse
I would like to know the same, as well as what license it is under... Also, I don't care about the network, but does it work on Oreo? Also, do you think I could customise the installer to install to a non-system location (/tmp) so that my flashable zip can use python?

hackintosh5 said:
I would like to know the same, as well as what license it is under... Also, I don't care about the network, but does it work on Oreo? Also, do you think I could customise the installer to install to a non-system location (/tmp) so that my flashable zip can use python?
Click to expand...
Click to collapse
Idk about OP, but I can surely post my source for python 2.7 on arm/arm64. I compiled it like a year ago, but it wasn't too bad, just required a bunch of patches and code for dlopen

I just want to say thank you so much.