Fix env parsing off by one

[serpilliere]

Fix issue #34

[serpilliere]

This PR fixes the off by one described in #34

Note:
It seems that the PAM environment only selects arbitrary variables

pam/src/client.rs

Line 170 in 1bc5a7e

self.set_env("HOME", user.home_dir().to_str().unwrap())?;

        self.set_env("HOME", user.home_dir().to_str().unwrap())?;
        self.set_env("PWD", user.home_dir().to_str().unwrap())?;
        self.set_env("SHELL", user.shell().to_str().unwrap())?;

But the PAM environment can set important other variables: for example in a kerberos environement, you have the KRB5CCNAME which points to the kerberos ticket for the user freshly logged in using pam.
This variable is in most system forwarded to the user environment (for example in SSH).

So if you are ok with this, maybe we could modify this code to inherit every environment variable positioned by the PAM to the process, instead of just arbitrary one.

Or if you are not ok with this principle, maybe we could expose an API for get all pam variable to the use api, something in the client.rs like:

    /// Retreive environement variable set by pam
    pub fn get_env_list(&mut self) -> Vec<(String, String)> {
        let pam_env = getenvlist(self.handle);
        let mut env = vec![];
        for (name, value) in pam_env {
            env.push((name, value));
        }
        env
    }

So the end user could do this on its own

Note: I think in an old version of your code, you forwarded every environment variables if I remember correctly.

[serpilliere]

Hi @1wilkens
I added the get_env_list function to the client, so the user will be able to retrieve PAM environment variable.
Moreover, I added a set of those environment variable to the initialize_environment so by default it will be pushed to the logged env.