RDA Python package, including a C code wrapper, to execute commandline applications via setuid for effective and common user names.

Overview

rda_python_setuid provides a C binary (pywrapper) that acquires a setuid effective user, then execvs a Python entry point script. This allows Python programs to run as a designated common user (e.g. gdexdata) without requiring sudo access.

Two modes are supported:

• Mode 1 (CommonUser program): a symlink dsarch -> pywrapper runs setuid_dsarch as the common user.
• Mode 2 (pgstart specialist): a copy pgstart_zji runs any command as specialist zji via pgstart.py, restricted to authorized users.

Dependency requirement

Any Python package whose programs are to be run via the setuid mechanism must declare rda_python_setuid as a dependency in its pyproject.toml:

[project]
dependencies = [
  "rda_python_setuid",
  ...
]

It must also register each wrapped program's connector entry point with a setuid_ prefix:

[project.scripts]
"setuid_dsarch" = "rda_python_dsarch.dsarch:main"

pip install then places setuid_dsarch in the environment's bin/ directory automatically. pywrapper-install --link locks it down to chmod 700 so users cannot bypass the setuid wrapper by running it directly.

Environment setup

Option A — Python venv (DECS machines)

python3 -m venv $ENVHOME          # e.g. /glade/u/home/gdexdata/gdexmsenv
source $ENVHOME/bin/activate
pip install rda_python_setuid rda_python_dsarch ...

Option B — Conda (DAV/Casper)

conda create -n pg-gdex python=3.10
conda activate pg-gdex
pip install rda_python_setuid rda_python_dsarch ...

The conda environment is typically at /glade/work/gdexdata/conda-envs/pg-gdex.

Installation

After setting up the environment and installing packages, run pywrapper-install with no arguments to display the full user guide:

pywrapper-install

Full setuid setup (requires sudo access to CommonUser)

# 1. Install the target package (pulls in rda_python_setuid automatically):
pip install rda_python_dsarch

# 2. Compile pywrapper C binary (once per environment):
pywrapper-install --user gdexdata

# 3. Wire up each program as a setuid entry:
pywrapper-install --link dsarch --user gdexdata

# 4. Optionally, allow a specialist to run commands as themselves:
pywrapper-install --pgstart --user zji

Simple install (no sudo required, runs as current user)

Users who do not need the setuid mechanism can skip steps 2–4 and create a direct symlink from dsarch to setuid_dsarch:

pip install rda_python_dsarch
pywrapper-install --link dsarch --simple

Runtime flow

user runs:  dsarch [args]
              |  (symlink -> pywrapper, setuid bit -> EUID=gdexdata)
pywrapper.c:  execv(bin/setuid_dsarch, args)
              |  (chmod 700, only gdexdata can exec directly)
setuid_dsarch: calls dsarch:main() as gdexdata

Github

https://github.com/NCAR/rda-python-setuid