[](https://github.com/sthima/libstapsdt) [](https://travis-ci.org/sthima/libstapsdt) [](https://libstapsdt.readthedocs.org/) ------------------------------------------------------------------------------- `libstapsdt` is a library which allows creating and firing Systemtap's USDT probes at runtime. It's inspired on [chrisa/libusdt](https://github.com/chrisa/libusdt/). The goal of this library is to add USDT probes functionality to dynamic languages. ## Table of Contents - [Table of Contents](#table-of-contents) - [How it works](#how-it-works) - [Dependencies](#dependencies) - [Ubuntu 16.04](#ubuntu-1604) - [Install](#install) - [Demo](#demo) - [Run tests](#run-tests) - [Write your own wrapper](#write-your-own-wrapper) ## How it works Systemtap's USDT implementation allows only statically defined probes because they are set as ELF notes by the compiler. To create probes at runtime, `libstapsdt` takes advantage of shared libraries: it creates a small library with an ELF note and links it at runtime. This way, most existing tools will keep working as expected. ## Dependencies `libstapsdt` currently requires the following dependencies: * libelf (from elfutils) ### Ubuntu 16.04 ```bash sudo apt install libelf1 libelf-dev ``` ## Install To build and install libstapsdt, just run: ```bash make sudo make install sudo ldconfig ``` ## Demo There's a demo program available. To build it, run: ```bash make demo # Executable will be available at ./demo ``` Usage: ```bash ./demo PROVIDER_NAME PROBE_NAME ``` After running the demo program, it can be instrumented with proper tools. Here's an example using [eBPF/bcc](https://github.com/iovisor/bcc) trace tool (built from source): ```bash sudo /usr/share/bcc/tools/trace -p $(pgrep demo) 'u::PROBE_NAME' ``` ## Run tests To run tests, just run the command below. Please be aware that there are only a few tests for now, but more will be added in the future. ```bash make test ``` # Wrappers Here is a list of wrappers for other languages: * [Python](https://pypi.org/project/stapsdt/) * [NodeJS](https://www.npmjs.com/package/usdt) * [Go](https://github.com/mmcshane/salp) ## Write your own wrapper `libstapsdt` is written in C, which makes it very portable to almost any language. Most dynamic languages provide a way to wrap C code. Feel free to develop a wrapper in your language of choice. If you do, please let us know to update our wrappers list!