The code for creating a Passwd from the fields of the raw syscall result
assumed that the syscall would return valid C strings in all non-error
cases. This is not true, and at least one platform (Android) will
populate the fields with null pointers where they are not supported.
To fix this and prevent the error from happening again, this commit
changes `cstr2string(ptr)` to check for a null pointer, and return an
`Option<String>`, with `None` being the null pointer case. While
arguably it should be the caller's job to check for a null pointer
before calling (since the safety precondition is that the pointer is to
a valid C string), relying on the type checker to force remembering this
edge case is safer in the long run.
`LANGUAGE=C` is not enough, `LC_ALL=C` is needed as the environment
variable that overrides all the other localization settings.
e.g.
```bash
$ LANGUAGE=C id foobar
id: ‘foobar’: no such user
$ LC_ALL=C id foobar
id: 'foobar': no such user
```
* replace `LANGUAGE` with `LC_ALL` as environment variable in the tests
* fix the the date string of affected uutils
* replace `‘` and `’` with `'`
A lot of tests depend on GNU's coreutils to be installed in order
to obtain reference values during testing.
In these cases testing is limited to `target_os = linux`.
This PR installs GNU's coreutils on "github actions" and adjusts the
tests for `who`, `stat` and `pinky` in order to be compatible with macOS.
* `brew install coreutils` (prefix is 'g', e.g. `gwho`, `gstat`, etc.
* switch paths for testing to something that's available on both OSs,
e.g. `/boot` -> `/bin`, etc.
* switch paths for testing to the macOS equivalent,
e.g. `/dev/pts/ptmx` -> `/dev/ptmx`, etc.
* exclude paths when no equivalent is available,
e.g. `/proc`, `/etc/fstab`, etc.
* refactor tests to make better use of the testing API
* fix a warning in utmpx.rs to print to stderr instead of stdout
* fix long_usage text in `who`
* fix minor output formatting in `stat`
* the `expected_result` function should be refactored
to reduce duplicate code
* more tests should be adjusted to not only run on `target_os = linux`
This closes#2181.
`who --lookup` is failing with a runtime panic (double free).
Since `crate::dns-lookup` already includes a safe wrapper for `getaddrinfo`
I used this crate instead of further debugging the existing code in
utmpx::canon_host().
* It was neccessary to remove the version constraint for libc in uucore.
