Function fix_pip_cache_ownership 

pub fn fix_pip_cache_ownership(user_home: &str) -> PipCacheFixResult

Fix ownership of the pip cache directory (~/.cache/pip).

When installation steps use sudo pip install, the pip cache directory (~/.cache/pip) can end up owned by root. This prevents the unprivileged user from writing to the cache, causing permission errors on subsequent pip install runs.

This function:

1. Checks if ~/.cache/pip exists
2. Compares the directory’s owner UID with the current effective UID
3. If the owner is root (UID 0) and we know the target user (via SUDO_USER or HOME metadata), runs chown -R to fix ownership

Arguments

• user_home - The user’s home directory path (e.g., /home/user)

Returns

A PipCacheFixResult indicating what action was taken.

Safety

Uses libc::geteuid() to check current effective UID. The chown command is only executed when running as root with SUDO_USER set, which is the expected scenario when sudo pip operations have corrupted cache ownership.