ios_system: Drop-in replacement for system() in iOS programs

When porting Unix utilities to iOS (vim, TeX, python...), sometimes the source code executes system commands, using system() calls. These calls are rejected at compile time, with: error: 'system' is unavailable: not available on iOS.

This project provides a drop-in replacement for system(). Simply add the following lines at the beginning of you header file:

extern int ios_system(char* cmd);
#define system ios_system

link with the ios_system.framework, and your calls to system() will be handled by this framework.

The commands available are defined in ios_system.m. They are configurable through a series of #define.

There are, first, shell commands (ls, cp, rm...), archive commands (curl, tar, gz, compress...) plus a few interpreted languages (python, lua, TeX). Scripts written in one of the interpreted languages are also executed, if they are in the $PATH.

For each set of commands, we need to provide the associated framework. Frameworks for small commands are in this project. Frameworks for interpreted languages are larger, and available separately: python, lua and TeX. Some commands (curl, python) require OpenSSH and libssl2, which you will have to download and compile separately.

This ios_system framework has been successfully ported into a shell, Blink and into an editor, iVim. In both cases, it provides a Unix look-and-feel (well, mostly feel).

Issues: In iOS, you cannot write in the ~ directory, only in ~/Documents/, ~/Library/ and ~/tmp. Most Unix programs assume the configuration files are in $HOME. So either you redefine $HOME to ~/Documents/ or you set configuration variables (using setenv) to some other place.

Here's what I have:

setenv PATH = $PATH:~/Library/bin:~/Documents/bin
setenv PYTHONHOME = $HOME/Library/
setenv SSH_HOME = $HOME/Documents/
setenv CURL_HOME = $HOME/Documents/
setenv HGRCPATH = $HOME/Documents/.hgrc/
setenv SSL_CERT_FILE = $HOME/Documents/cacert.pem

Your Mileage May Vary.

Installation:

Run the script ./get_sources.sh. This will download the latest sources form Apple OpenSource and patch them for compatibility with iOS.
(optional) Run the script ./get_python_lua.sh. It will download the sources for python and lua.
If you do not need Python, delete the python_grp folder, comment out the #define FEAT_PYTHON line in ios_system.m (if you are linking with iVim, also remove it from the CFLAGS of iVim).
If you do need Python: open ../python_ios/libffi-3.2.1/libffi.xcodeproj/, hit Build. It will create libffi.a. Click on Products, control-click on libffi.a, go to "Show in Finder". Copy it to the ../python_ios/ directory.
Same with Lua: if you do not need it, comment the #define FEAT_LUA line in ios_system.m.
If you need Tex, follow the instructions at https://github.com/holzschu/lib-tex, and link with the dynamic libraries created. Otherwise, comment out #define TEX_COMMANDS.
Open the Xcode project ios_system.xcodeproj and hit build. This will create the ios_system framework, ready to be included in your own projects. Alternatively, drag ios_system.xcodeproj into you project, add ios_system.framework to your linked binaries and compile.

CliffsDover/ios_system

ios_system: Drop-in replacement for system() in iOS programs

Installation: