[termux-packages] / README.md

termux-packages
===============
This project contains scripts and patches to cross compile and package packages for
the [Termux](http://termux.com/) Android application.


Overview
========
In a non-rooted Android device an app such as Termux may not write to system locations,
which is why every package is installed inside the private file area of the Termux app:
	PREFIX=/data/data/com.termux/files/usr

For simplicity while developing and building, the build scripts here assume that a /data
folder is reserved for use on the host builder, which requires setup:
	sudo mkdir /data
	sudo chown $USER /data

The basic flow is then to run "./build-package.sh $PKG", which
	- Sets up a patched stand-alone Android NDK toolchain
	- Reads packages/$PKG/build.sh to find out where to find the source code of the
	  package and how to build it.
	- Applies all patches in packages/$PKG/\*.patch
	- Builds the package and installs it to $PREFIX
	- Packages the package in one or more .dpkg files for distribution
Reading and following build-package.sh is the best way to understand what's going on here.

Additional utilities are contained here:
	- build-all.sh, used for building all packages in the correct order (using buildorder.py)
	- check-pie.sh, used for verifying that all binaries are using PIE, which is required for Android 5+
	- check-versions.sh, used for checking for package updates
	- clean-rebuild-all.sh, used for doing a clean rebuild of all packages (takes a couple of hours)
	- list-packages.sh, used for listing all packages with a one-line summary


Resources about cross-compiling packages
========================================
* [Linux From Scratch](http://www.linuxfromscratch.org/blfs/view/svn/index.html)

* [Beyond Linux From Scratch](http://www.linuxfromscratch.org/blfs/view/svn/)

* [Cross-Compiled Linux From Scratch](http://cross-lfs.org/view/svn/x86_64-64/)

* [OpenWrt](https://openwrt.org/), an embedded Linx distribution, contains [patches and build scripts](https://dev.openwrt.org/browser/packages)

* http://dan.drown.org/android contains [patches for cross-compiling to Android](http://dan.drown.org/android/src/) as well as [work notes](http://dan.drown.org/android/worknotes.html), including a modified dynamic linker to avoid messing with LD_LIBRARY_PATH.

* [CCTools](http://cctools.info/index.php?title=Main_Page) is an Android native IDE containing [patches for several programs](https://code.google.com/p/cctools/source/browse/#svn%2Ftrunk%2Fcctools-repo%2Fpatches) and [a bug tracker](https://code.google.com/p/cctools/issues/list).

* [BotBrew](http://botbrew.com/) was a package manager for rooted devices with [sources on github](https://github.com/jyio/botbrew). Based on opkg and was transitioning to apt.

* [Kivy recipes](https://github.com/kivy/python-for-android/tree/master/recipes) contains recipes for building packages for Android.


Common porting problems
=======================
* The Android bionic libc does not have iconv and gettext/libintl functionality built in. A package from the NDK, libandroid-support,
contains these and may be used by all packages.

* "error: z: no archive symbol table (run ranlib)" usually means that the build machines libz is used instead of the one for cross compilation, due to the builder library -L path being setup incorrectly

* rindex(3) is defined in &lt;strings.h&gt; but does not exist in NDK, but strrchr(3) from &lt;string.h&gt; is preferred anyway

* &lt;sys/termios.h&gt; does not exist, but &lt;termios.h&gt; is the standard location.

* &lt;sys/fcntl.h&gt; does not exist, but &lt;fcntl.h&gt; is the standard location.

* glob(3) system function (glob.h) - not in bionic, but use the libglob package

* undefined reference to 'rpl_malloc' and/or 'rpl_realloc': These functions are added by some autoconf setups
  when it fails to detect 0-safe malloc and realloc during cross-compilating. Avoided by defining
  "ac_cv_func_malloc_0_nonnull=yes ac_cv_func_realloc_0_nonnull=yes".
  See http://wiki.buici.com/xwiki/bin/view/Programing+C+and+C%2B%2B/Autoconf+and+RPL_MALLOC

* cmake and cross compiling: http://www.cmake.org/Wiki/CMake_Cross_Compiling
  CMAKE_FIND_ROOT_PATH=$TERMUX_PREFIX to search there.
  CMAKE_FIND_ROOT_PATH_MODE_LIBRARY=ONLY and
  CMAKE_FIND_ROOT_PATH_MODE_INCLUDE=ONLY
  for only searching there and don't fall back to build machines

* Android is removing sys/timeb.h because it was removed in POSIX 2008, but ftime(3) can be replaced with gettimeofday(2)

* mempcpy(3) is a GNU extension. We have added it to &lt;string.h&gt; provided TERMUX_EXPOSE_MEMPCPY is defined,
  so use something like CFLAGS+=" -DTERMUX_EXPOSE_MEMPCPY=1" for packages expecting that function to exist.


dlopen() and RTLD&#95;&#42; flags
=================================
&lt;dlfn.h&gt; declares

> enum { RTLD_NOW  = 2, RTLD_LAZY = 1, RTLD_LOCAL  = 0, RTLD_GLOBAL = 0x00100, RTLD_NOLOAD = 4}; // 64 bit
> enum { RTLD_NOW  = 0, RTLD_LAZY = 1, RTLD_LOCAL  = 0, RTLD_GLOBAL = 2,       RTLD_NOLOAD = 4}; // 32 bit

These differs from glibc ones in that

1. They are not preprocessor #define:s so cannot be checked for with #ifdef RTLD_GLOBAL (dln.c in ruby does this)
2. They differ in value from glibc ones, so cannot be hardcoded in files (DLFCN.py in python does this)
3. They are missing some values (RTLD_BINDING_MASK, RTLD_NOLOAD, ...)


RPATH, LD_LIBRARY_PATH AND RUNPATH
==================================
On desktop linux the linker searches for shared libraries in:
1. RPATH - a list of directories which is linked into the executable, supported on most UNIX systems. It is ignored if RUNPATH is present.
2. LD_LIBRARY_PATH - an environment variable which holds a list of directories
3. RUNPATH - same as RPATH, but searched after LD_LIBRARY_PATH, supported only on most recent UNIX systems, e.g. on most current Linux systems
The Android linker (/system/bin/linker) does not support RPATH or RUNPATH, so we set LD_LIBRARY_PATH=$USR/lib and try to avoid building
useless rpath entries with --disable-rpath configure flags.
Another option to avoid depending on LD_LIBRARY_PATH would be supplying a custom linker - this is not done due to the overhead of maintaining a custom linker.


Warnings about unused DT entries
================================
Starting from 5.1 the Android linker warns about VERNEED (0x6FFFFFFE) and VERNEEDNUM (0x6FFFFFFF) ELF dynamic sections:
	WARNING: linker: $BINARY: unused DT entry: type 0x6ffffffe arg ...
	WARNING: linker: $BINARY: unused DT entry: type 0x6fffffff arg ...
These may come from version scripts in a Makefile such as:
	-Wl,--version-script=$(top_srcdir)/proc/libprocps.sym
The termux-elf-cleaner utilty is run from build-package.sh and should normally take care of that problem.


Bootstrapping
=============
To get files on device one option is:
	udpsvd -vE 0.0.0.0 8069 tftpd -c . # Run on device. -c arg to allow file uploading
	printf "mode binary\nput out.md\nquit" | tftp 192.168.0.12 8069 # on computer
Another is with ftp:
	tcpsvd -vE 0.0.0.0 8021 ftpd -w . # Run on device. -w arg to allow file uploading
	printf "put tmp.c\nquit" | ftp -n 192.168.0.12 8021 # Run on computer. -n arg to use anonymous login
NOTE: The ftpd and tftpd programs has been patched to run without chroot. This means that the directory
      serving is only the starting point and clients may cd out of if the access the whole system!
Commit	Line	Data
798619b9 FF	1	termux-packages
	2	===============
	3	This project contains scripts and patches to cross compile and package packages for
	4	the [Termux](http://termux.com/) Android application.
	5
	6
	7	Overview
	8	========
	9	In a non-rooted Android device an app such as Termux may not write to system locations,
	10	which is why every package is installed inside the private file area of the Termux app:
	11	PREFIX=/data/data/com.termux/files/usr
	12
	13	For simplicity while developing and building, the build scripts here assume that a /data
	14	folder is reserved for use on the host builder, which requires setup:
	15	sudo mkdir /data
	16	sudo chown $USER /data
	17
	18	The basic flow is then to run "./build-package.sh $PKG", which
	19	- Sets up a patched stand-alone Android NDK toolchain
	20	- Reads packages/$PKG/build.sh to find out where to find the source code of the
	21	package and how to build it.
	22	- Applies all patches in packages/$PKG/\*.patch
	23	- Builds the package and installs it to $PREFIX
	24	- Packages the package in one or more .dpkg files for distribution
	25	Reading and following build-package.sh is the best way to understand what's going on here.
	26
	27	Additional utilities are contained here:
	28	- build-all.sh, used for building all packages in the correct order (using buildorder.py)
	29	- check-pie.sh, used for verifying that all binaries are using PIE, which is required for Android 5+
	30	- check-versions.sh, used for checking for package updates
	31	- clean-rebuild-all.sh, used for doing a clean rebuild of all packages (takes a couple of hours)
	32	- list-packages.sh, used for listing all packages with a one-line summary
	33
	34
	35	Resources about cross-compiling packages
	36	========================================
	37	* [Linux From Scratch](http://www.linuxfromscratch.org/blfs/view/svn/index.html)
	38
	39	* [Beyond Linux From Scratch](http://www.linuxfromscratch.org/blfs/view/svn/)
	40
	41	* [Cross-Compiled Linux From Scratch](http://cross-lfs.org/view/svn/x86_64-64/)
	42
	43	* [OpenWrt](https://openwrt.org/), an embedded Linx distribution, contains [patches and build scripts](https://dev.openwrt.org/browser/packages)
	44
	45	* http://dan.drown.org/android contains [patches for cross-compiling to Android](http://dan.drown.org/android/src/) as well as [work notes](http://dan.drown.org/android/worknotes.html), including a modified dynamic linker to avoid messing with LD_LIBRARY_PATH.
	46
	47	* [CCTools](http://cctools.info/index.php?title=Main_Page) is an Android native IDE containing [patches for several programs](https://code.google.com/p/cctools/source/browse/#svn%2Ftrunk%2Fcctools-repo%2Fpatches) and [a bug tracker](https://code.google.com/p/cctools/issues/list).
	48
	49	* [BotBrew](http://botbrew.com/) was a package manager for rooted devices with [sources on github](https://github.com/jyio/botbrew). Based on opkg and was transitioning to apt.
	50
	51	* [Kivy recipes](https://github.com/kivy/python-for-android/tree/master/recipes) contains recipes for building packages for Android.
	52
	53
	54	Common porting problems
	55	=======================
	56	* The Android bionic libc does not have iconv and gettext/libintl functionality built in. A package from the NDK, libandroid-support,
	57	contains these and may be used by all packages.
	58
	59	* "error: z: no archive symbol table (run ranlib)" usually means that the build machines libz is used instead of the one for cross compilation, due to the builder library -L path being setup incorrectly
	60
	61	* rindex(3) is defined in <strings.h> but does not exist in NDK, but strrchr(3) from <string.h> is preferred anyway
	62
	63	* <sys/termios.h> does not exist, but <termios.h> is the standard location.
	64
65	* <sys/fcntl.h> does not exist, but <fcntl.h> is the standard location.
66
67	* glob(3) system function (glob.h) - not in bionic, but use the libglob package
68
69	* undefined reference to 'rpl_malloc' and/or 'rpl_realloc': These functions are added by some autoconf setups
70	when it fails to detect 0-safe malloc and realloc during cross-compilating. Avoided by defining
71	"ac_cv_func_malloc_0_nonnull=yes ac_cv_func_realloc_0_nonnull=yes".
72	See http://wiki.buici.com/xwiki/bin/view/Programing+C+and+C%2B%2B/Autoconf+and+RPL_MALLOC
73
74	* cmake and cross compiling: http://www.cmake.org/Wiki/CMake_Cross_Compiling
75	CMAKE_FIND_ROOT_PATH=$TERMUX_PREFIX to search there.
76	CMAKE_FIND_ROOT_PATH_MODE_LIBRARY=ONLY and
77	CMAKE_FIND_ROOT_PATH_MODE_INCLUDE=ONLY
78	for only searching there and don't fall back to build machines
79
80	* Android is removing sys/timeb.h because it was removed in POSIX 2008, but ftime(3) can be replaced with gettimeofday(2)
81
82	* mempcpy(3) is a GNU extension. We have added it to <string.h> provided TERMUX_EXPOSE_MEMPCPY is defined,
83	so use something like CFLAGS+=" -DTERMUX_EXPOSE_MEMPCPY=1" for packages expecting that function to exist.
84
85
86	dlopen() and RTLD_* flags
87	=================================
88	<dlfn.h> declares
89
90	> enum { RTLD_NOW = 2, RTLD_LAZY = 1, RTLD_LOCAL = 0, RTLD_GLOBAL = 0x00100, RTLD_NOLOAD = 4}; // 64 bit
91	> enum { RTLD_NOW = 0, RTLD_LAZY = 1, RTLD_LOCAL = 0, RTLD_GLOBAL = 2, RTLD_NOLOAD = 4}; // 32 bit
92
93	These differs from glibc ones in that
94
95	1. They are not preprocessor #define:s so cannot be checked for with #ifdef RTLD_GLOBAL (dln.c in ruby does this)
96	2. They differ in value from glibc ones, so cannot be hardcoded in files (DLFCN.py in python does this)
97	3. They are missing some values (RTLD_BINDING_MASK, RTLD_NOLOAD, ...)
98
99
100	RPATH, LD_LIBRARY_PATH AND RUNPATH
101	==================================
102	On desktop linux the linker searches for shared libraries in:
103	1. RPATH - a list of directories which is linked into the executable, supported on most UNIX systems. It is ignored if RUNPATH is present.
104	2. LD_LIBRARY_PATH - an environment variable which holds a list of directories
105	3. RUNPATH - same as RPATH, but searched after LD_LIBRARY_PATH, supported only on most recent UNIX systems, e.g. on most current Linux systems
106	The Android linker (/system/bin/linker) does not support RPATH or RUNPATH, so we set LD_LIBRARY_PATH=$USR/lib and try to avoid building
107	useless rpath entries with --disable-rpath configure flags.
108	Another option to avoid depending on LD_LIBRARY_PATH would be supplying a custom linker - this is not done due to the overhead of maintaining a custom linker.
109
110
111	Warnings about unused DT entries
112	================================
113	Starting from 5.1 the Android linker warns about VERNEED (0x6FFFFFFE) and VERNEEDNUM (0x6FFFFFFF) ELF dynamic sections:
114	WARNING: linker: $BINARY: unused DT entry: type 0x6ffffffe arg ...
115	WARNING: linker: $BINARY: unused DT entry: type 0x6fffffff arg ...
116	These may come from version scripts in a Makefile such as:
117	-Wl,--version-script=$(top_srcdir)/proc/libprocps.sym
118	The termux-elf-cleaner utilty is run from build-package.sh and should normally take care of that problem.
119
120
121	Bootstrapping
122	=============
123	To get files on device one option is:
124	udpsvd -vE 0.0.0.0 8069 tftpd -c . # Run on device. -c arg to allow file uploading
125	printf "mode binary\nput out.md\nquit" \| tftp 192.168.0.12 8069 # on computer
126	Another is with ftp:
127	tcpsvd -vE 0.0.0.0 8021 ftpd -w . # Run on device. -w arg to allow file uploading
128	printf "put tmp.c\nquit" \| ftp -n 192.168.0.12 8021 # Run on computer. -n arg to use anonymous login
129	NOTE: The ftpd and tftpd programs has been patched to run without chroot. This means that the directory
130	serving is only the starting point and clients may cd out of if the access the whole system!
131