mbed TLS should build out of the box on most systems. Some platform specific options are available in the fully-documented configuration file *include/mbedtls/config.h*, which is also the place where features can be selected.
The main systems used for development are CMake and yotta. Those systems are always complete and up-to-date. The others should reflect all changes present in the CMake and yotta build system, but some features are not ported there by default.
Please note that the yotta option is slightly different from the other build systems:
- a more minimalistic configuration file is used by default
- depending on the yotta target, features of mbed OS will be used in examples and tests
Yotta
-----
`yotta <http://yottabuild.org>` is a package manager and build system developped by mbed; it is the build system of mbed OS. To install it on your platform, please follow the `yotta installation instructions <http://docs.yottabuild.org/#installing>`.
Once yotta is installed, you can use it to download the latest version of mbed TLS form the yotta registry with::
yotta install mbedtls
and build it with::
yotta build
If, on the other hand, you already have a copy of mbed TLS from a source other than the yotta registry, for example from cloning our github repository, or from downloading a tarball of the standalone edition, then you'll need first need to generate the yotta module by running::
yotta/create-module.sh
from the mbed TLS root directory. This will create the yotta module in the *yotta/module* directory. You can then change to that directory and build as usual::
cd yotta/module
yotta build
In any case, you'll probably want to set the yotta target before building unless it's already set globally; for more information on using yotta, please consult the `yotta documentation <http://docs.yottabuild.org/>`.
The yotta edition of mbed TLS includes a few example programs, some of which demonstrate integration with mbed OS; for more details, please consult the `Readme at the root of the yotta module <https://github.com/ARMmbed/mbedtls/blob/development/yotta/data/README.md>`.
We intentionally only use the absolute minimum of **Make** functionality, as we have discovered that a lot of **Make** features are not supported on all different implementations of Make on different platforms. As such, the Makefiles sometimes require some handwork or `export` statements in order to work for your platform.
The tests need Perl to be built and run. If you don't have Perl installed, you can skip buiding the tests with::
make no_test
You'll still be able to run a much smaller set of tests with::
programs/test/selftest
In order to build for a Windows platform, you should use WINDOWS_BUILD=1 if the target is Windows but the build environment is Unix-like (for instance when cross-compiling, or compiling from an MSYS shell), and WINDOWS=1 if the build environment is a Windows shell (for instance using mingw32-make) (in that case some targets will not be available).
Setting the variable SHARED in your environment will build a shared library in addition to the static library. Setting DEBUG gives you a debug build. You can override CFLAGS and LDFLAGS by setting them in your environment or on the make command line; if you do so, essential parts such as -I will still be preserved. Warning options may be overridden separately using WARNING_CFLAGS.
Depending on your platform, you might run into some issues. Please check the Makefiles in *library/*, *programs/* and *tests/* for options to manually add or remove for specific platforms. You can also check `the mbed TLS Knowledge Base <https://tls.mbed.org/kb>`_ for articles on your platform or issue.
There are many different build modes available within the CMake buildsystem. Most of them are available for gcc and clang, though some are compiler-specific:
Note that, with CMake, if you want to change the compiler or its options after you already ran CMake, you need to clear its cache first, eg (using GNU find)::
The solution file 'mbedTLS.sln' contains all the basic projects needed to build the library and all the programs. The files in tests are not generated and compiled, as these need a perl environment as well. However, the `selftest` program in *programs/test/* is still available.
We've included example programs for a lot of different features and uses in *programs/*. Most programs only focus on a single feature or usage scenario, so keep that in mind when copying parts of the code.
mbed TLS includes an elaborate test suite in *tests/* that initially requires Perl to generate the tests files (e.g. *test_suite_mpi.c*). These files are generates from a **function file** (e.g. *suites/test_suite_mpi.function*) and a **data file** (e.g. *suites/test_suite_mpi.data*). The **function file** contains the test functions. The **data file** contains the test cases, specified as parameters that will be passed to the test function.
-*tests/ssl-opt.sh* runs integration tests for various TLS options (renegotiation, resumption, etc.) and tests interoperability of these options with other implementations.
-*tests/compat.sh* tests interoperability of every ciphersuite with other implementations.
-*tests/scripts/test-ref-configs.pl* test builds in various reduced configurations.
We provide some non-standard configurations focused on specific use cases in the configs/ directory. You can read more about those in configs/README.txt
We graciously accept bugs and contributions from the community. There are some requirements we need to fulfil in order to be able to integrate contributions in the main code.
Simple bug fixes to existing code do not contain copyright themselves and we can integrate those without any issue. The same goes for trivial contributions.
For larger contributions, e.g. a new feature, the code possible falls under copyright law. We then need your consent to share in the ownership of the copyright. We have a form for that, which we will mail to you in case you submit a contribution or pull request that we deem this necessary for.
