AIX Open Source

Hi everyone,

If you've used our IBM Open SDK for Rust on AIX Community Edition for 1.84 (available for download at: https://early-access.ibm.com/software/support/trial/cst/programwebsite.wss?siteId=2171&h=null&p=null )
and have feedback or questions for us we'd be interested to hear it!

We'll also post in this thread to address some common issues you might be encountering.

Thanks,

Adam

A migration tip: AIX support in the broader Rust crate ecosystem in under active development, so it's often necessary to move dependencies to newer versions when building for AIX to work around compilation issues caused by limited support.

We maintain a list of crates for which IBM has contributed AIX support, and the versions where that support starts, in our official documentation here: https://ibmdocs-test.dcs.ibm.com/docs/en/osfroa/1.84?topic=started-introducing-rustc-compiler

A migration tip: AIX support in the broader Rust crate ecosystem in under active development, so it's often necessary to move dependencies to newer versions when building for AIX to solve build issues related to limited support.

We maintain a list of crates for which IBM has contributed AIX support, and the versions where that support starts, in our official documentation here: 
https://ibmdocs-test.dcs.ibm.com/docs/en/osfroa/1.84?topic=started-introducing-rustc-compiler

Errors related to sa_sigaction on AIX and How to Mitigate Them

If you encounter errors similar to the following, it is likely due to using an outdated crate version (such as jobserver in this example). Please update your Cargo.toml to use the fixed versions, e.g., jobserver v0.1.33.

error[E0609]: no field `sa_union` on type `sigaction`
   --> /home/buildusr/.cargo/registry/src/index.crates.io-d11c229612889eed/jobserver-0.1.32/src/unix.rs:399:17
    |
399 |             new.sa_union.__su_sigaction = sigusr1_handler;
    |                 ^^^^^^^^ unknown field
    |
    = note: available fields are: `sa_sigaction`, `sa_mask`, `sa_flags

This kind of error can also occur if your code references sa_union.__su_sigaction on AIX. In that case, update it to use sa_sigaction directly instead.

This change is due to a recent update in the libc crate, where sa_sigaction is now defined as a direct member of struct sigaction on AIX. In the AIX system header, struct sigaction contains a union named sa_union, which includes two members: __su_handler and __su_sigaction, corresponding to the sa_handler and sa_sigaction fields defined in the POSIX specification. Previously, the definition of struct sigaction in the libc crate mirrored this AIX structure directly, using the union. As a result, any Rust code referencing sa_sigaction, whether in shipped crates or user code, needed to use sa_union.__su_sigaction on AIX.

Other operating systems, such as Linux, also define a union for sa_handler and sa_sigaction within struct sigaction. However, the libc crate implementations on those platforms define sa_sigaction directly as a member of struct sigaction rather than within a union, which greatly simplifies the code.

To bring AIX in line with other platforms, we have updated the libc crate's AIX implementation to define sa_sigaction as a direct member of struct sigaction. This change is included in libc v0.2.171 and later. We have also updated the nix (v0.29.0), jobserver (v0.1.33), and signal-hook (patch pending review) crates, along with relevant test cases, to reflect this change.