Got an error while building to SunOS

[KrutNA]

Steps to reproduce:

Try to build users crate to sparcv9-sun-solaris or x86_64-sun-solaris archs.
I'm trying to cross compile fselect and used cross for cross compiling to other archs

Expected:

Compiled successfully.

Got:

   Compiling users v0.9.1
error[E0425]: cannot find function `getgrouplist` in crate `libc`
   --> /cargo/registry/src/github.com-1ecc6299db9ec823/users-0.9.1/src/base.rs:707:15
    |
707 |         libc::getgrouplist(name.as_ptr(), gid, buff.as_mut_ptr(), &mut count)
    |               ^^^^^^^^^^^^ help: a function with a similar name exists: `getgroups`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0425`.
error: could not compile `users`.
warning: build failed, waiting for other jobs to finish...
error: build failed

As I checked crate libc, I found in documentation: there is no functions getgrouplist for this archs.
libc/platform-specific-documentation

[ogham]

I did some digging into this. Oracle's libc documentation has a page for getgrouplist, but I've seen references to other projects saying Solaris doesn't have that function, so there must be a reason why it's missing from Rust's libc.

If we can't use getgrouplist, then, we'd have to write our own version. However — and this is where it gets difficult — we'd have to iterate through the groups list using getgrent/setgrent/endgrent, which mutates a structure internal to libc that's effectively global. See the doc comment for all_users for why this is so annoying. As this is meant to be a library, rather than an application, we have no way of ensuring that our getgrouplist replacement is the only code using those three functions exclusively.

I'll have to mark this one as "help wanted" until a better solution comes along. The only workaround I can offer is to add a feature flag to omit all the functions that use getgrouplist, but that doesn't help you if you're trying to port an existing application.

[Toasterson]

@papertigers @jclulow can we push that function on the illumos side into libc? I think this library is the only one implementing user related functionality in rust so some better support is good for rust projects wanting to check/modify os user configs.

I get this error aswell on illumos

[papertigers]

It's there now: https://rust-lang.github.io/libc/x86_64-unknown-illumos/doc/libc/fn.getgrouplist.html
And the corresponding illumos commit: illumos/illumos-gate@f2c438c

[Toasterson]

Awesome thanks. Now with a modern enough version of libc and your PR it compiled. Up to testing metadata agent on bhyve :)

[nospam3089]

For what it's worth, the addition of getgrouplist was mentioned in the Release Notes for r151038.

[Toasterson]

Ping @ogham getgrouplist has been added for illumos libc in rust. do you need anything else?