-# termux-packages
-Scripts and patches for building Termux packages
+Termux packages
+===============
+[](https://gitter.im/termux/termux)
+
+This project contains scripts and patches to cross compile and package packages for
+the [Termux](https://termux.com/) Android application.
+
+The scripts and patches to build each package is licensed under the same license as
+the actual package (so the patches and scripts to build bash are licensed under
+the same license as bash, while the patches and scripts to build python are licensed
+under the same license as python, etc).
+
+NOTE: This is in a rough state - be prepared for some work and frustrations, and give
+feedback if you find incorrect our outdated things!
+
+
+Build environment on Ubuntu 16.04
+=================================
+Packages are normally built using Ubuntu 16.04. Most packages should build also under
+other Linux distributions (or even on OS X), but those environments will need manual setup
+adapted from the below setup for Ubuntu:
+
+* Run `scripts/setup-ubuntu.sh` to install required packages and setup the `/data/` folder.
+
+* Run `scripts/setup-android-sdk.sh` to install the Android SDK and NDK at `$HOME/lib/android-{sdk,ndk}`.
+
+
+Build environment using Docker
+==============================
+A Docker container configured for building images can be downloaded and run with:
+
+ ./scripts/run-docker.sh
+
+This will set you up with a interactive prompt in a container, where this source folder
+is mounted as the /root/termux-packages data volume, so changes are kept in sync between
+the host and the container when trying things out before committing, and built deb files
+will be available on the host in the `debs/` directory just as when building on the host.
+
+Build commands can be given to be executed in the docker container directly:
+
+ ./scripts/run-docker.sh ./build-package.sh libandroid-support
+
+will launch the docker container, execute the `./build-package.sh libandroid-support`
+command inside it and afterwards return you to the host prompt, with the newly built
+deb in `debs/` to try out.
+
+
+Building a package
+==================
+The basic build operation is to run `./build-package.sh $PKG`, which:
+
+* Sets up a patched stand-alone Android NDK toolchain if necessary.
+
+* Reads `packages/$PKG/build.sh` to find out where to find the source code of the package and how to build it.
+
+* Extracts the source in `$HOME/.termux-build/$PKG/src`.
+
+* Applies all patches in packages/$PKG/\*.patch.
+
+* Builds the package under `$HOME/.termux-build/$PKG/` (either in the build/ directory there or in the
+ src/ directory if the package is specified to build in the src dir) and installs it to `$PREFIX`.
+
+* Extracts modified files in `$PREFIX` into `$HOME/.termux-build/$PKG/massage` and massages the
+ files there for distribution (removes some files, splits it up in sub-packages, modifies elf files).
+
+* Creates a deb package file for distribution in `debs/`.
+
+Reading `build-package.sh` is the best way to understand what is going on.
+
+
+Additional utilities
+====================
+* build-all.sh: used for building all packages in the correct order (using buildorder.py).
+
+* clean-rebuild-all.sh: used for doing a clean rebuild of all packages.
+
+* scripts/check-pie.sh: Used for verifying that all binaries are using PIE, which is required for Android 5+.
+
+* scripts/detect-hardlinks.sh: Used for finding if any packages uses hardlinks, which does not work on Android M.
+
+* scripts/check-versions.sh: used for checking for package updates.
+
+* scripts/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/stable/)
+
+* [Cross-Compiled Linux From Scratch](http://www.clfs.org/view/CLFS-3.0.0-SYSVINIT/mips64-64/)
+
+* [OpenWrt](https://openwrt.org/) as 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`.
+
+* [Kivy recipes](https://github.com/kivy/python-for-android/tree/master/pythonforandroid/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 <strings.h> but does not exist in NDK, but strrchr(3) from <string.h> is preferred anyway
+
+* <sys/termios.h> does not exist, but <termios.h> is the standard location.
+
+* <sys/fcntl.h> does not exist, but <fcntl.h> is the standard location.
+
+* glob(3) system function (glob.h) - not in bionic, but use the `libandroid-glob` package
+
+* [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 <string.h> 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_* flags
+=================================
+<dlfcn.h> originally declares
+
+ enum { RTLD_NOW=0, RTLD_LAZY=1, RTLD_LOCAL=0, RTLD_GLOBAL=2, RTLD_NOLOAD=4}; // 32-bit
+ enum { RTLD_NOW=2, RTLD_LAZY=1, RTLD_LOCAL=0, RTLD_GLOBAL=0x00100, RTLD_NOLOAD=4}; // 64-bit
+
+These differs from glibc ones in that
+
+1. They are not preprocessor #define:s so cannot be checked for with `#ifdef RTLD_GLOBAL`. Termux patches this to #define values for compatibility with several packages.
+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, RUNPATH AND LD\_LIBRARY\_PATH
+====================================
+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
+
+The Android linker (/system/bin/linker) does not support `RPATH` or `RUNPATH`, so we set `LD_LIBRARY_PATH=$PREFIX/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.
~mdw / termux-packages / blobdiff