-# termux-packages
-Scripts and patches for building Termux packages
+Termux packages
+===============
+[](https://gitter.im/termux/termux)
+
+This project contains scripts and patches to build packages for the
+[Termux](https://termux.com/) Android application.
+
+Setting up a build environment using Docker
+===========================================
+For most people the best way to obtain an environment for building packages is by using Docker. This should work everywhere Docker is supported (replace `/` with `\` if using Windows) and ensures an up to date build environment that is tested by other package builders.
+
+Run the following script to setup a container (from an image created by [scripts/Dockerfile](scripts/Dockerfile)) suitable for building packages:
+
+ ./scripts/run-docker.sh
+
+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.
+
+The docker container used for building packages is a Ubuntu 16.10 installation with necessary packages
+pre-installed. The default user is a non-root user to avoid problems with package builds modifying the system
+by mistake, but `sudo` can be used to install additional Ubuntu packages to be used during development.
+
+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.
+
+Note that building packages can take up a lot of space (especially if `build-all.sh` is used to build all packages) and you may need to [increase the base device size](http://www.projectatomic.io/blog/2016/03/daemon_option_basedevicesize/) if running with a storage driver using a small base size of 10 GB.
+
+Build environment without Docker
+================================
+If you can't run Docker you can use a Ubuntu 16.10 installation (either by installing a virtual maching guest or on direct hardware) by using the below scripts:
+
+- 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}`.
+
+There is also a [Vagrantfile](scripts/Vagrantfile) available as a shortcut for setting up an Ubuntu installation with the above steps applied.
+
+Building a package
+==================
+The basic build operation is to run `./build-package.sh $PKG`, which:
+
+1. Sets up a patched stand-alone Android NDK toolchain if necessary.
+
+2. Reads `packages/$PKG/build.sh` to find out where to find the source code of the package and how to build it.
+
+3. Extracts the source in `$HOME/.termux-build/$PKG/src`.
+
+4. Applies all patches in packages/$PKG/\*.patch.
+
+5. Builds the package under `$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`.
+
+6. 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).
+
+7. Creates a deb package file for distribution in `debs/`.
+
+Reading [build-package.sh](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.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/check-versions.sh: used for checking for package updates.
+
+* scripts/list-packages.sh: used for listing all packages with a one-line summary.
+
+
+Resources
+=========
+* [Android changes for NDK developers](https://android.googlesource.com/platform/bionic/+/master/android-changes-for-ndk-developers.md)
+
+* [Linux From Scratch](http://www.linuxfromscratch.org/lfs/view/stable/)
+
+* [Beyond Linux From Scratch](http://www.linuxfromscratch.org/blfs/view/stable/)
+
+* [OpenWrt](https://openwrt.org/) as an embedded Linx distribution contains [patches and build scripts](https://dev.openwrt.org/browser/packages)
+
+* [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 `libandroid-support` package 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) does not exist, but strrchr(3) 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.
+
+* <sys/timeb.h> does not exist (removed in POSIX 2008), but ftime(3) can be replaced with gettimeofday(2).
+
+* <glob.h> does not exist, but is available through the `libandroid-glob` package.
+
+* SYSV shared memory is not supported by the kernel. A `libandroid-shmem` package, which emulates SYSV shared memory on top of the [ashmem](http://elinux.org/Android_Kernel_Features#ashmem) shared memory system, is available. Use it with `LDFLAGS+=" -landroid-shmem`.
+
+* SYSV semaphores is not supported by the kernel. Use unnamed POSIX semaphores instead (named semaphores are unimplemented).
+
+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 (which the linker warns about) with --disable-rpath configure flags. NOTE: Starting from Android 7.0 RUNPATH (but not RPATH) is supported.
+
+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/0x6fffffff). These may come from version scripts (`-Wl,--version-script=`). The termux-elf-cleaner utilty is run from build-package.sh and should normally take care of that problem. NOTE: Starting from Android 6.0 symbol versioning is supported.
~mdw / termux-packages / blobdiff