windows-sys bindings supported on Linux

[matheo-lucak]

Suggestion

Hello, firstly thanks for all the work to push on windows development.

I'm trying to use WinRM to communicate from a Linux client to Windows servers.
Compiling the WinRM client, and running it on a Windows machine works fine but compiling it on Linux fails, the linker fails to find required symbols of WinRM functions.

I've seen CI building Linux and testing for native linux for the C++/WinRT here. (Which I see has been deleted since for only cross building tests).
The crate windows-link also has a macro to run on non-windows targets

#[cfg(not(windows))]
#[macro_export]
macro_rules! link {
...
}

What is the scope of Linux support for the windows-sys crate ?

[kennykerr]

Do you have a minimal repro of what you're trying to accomplish? Keep in mind that the bindings for APIs are generated from metadata and I don't personally know much about WinRM or Linux. 😊

[riverar]

The only crates that continue to support limited non-Windows builds are:

• windows-bindgen and windows-metadata for code generation on non-Windows platforms
• windows-core and windows-result for COM support on non-Windows platforms

[tim-weis]

The #[cfg(not(windows))] gate is active when you're targeting a system that's not Windows. Is there (still) a practical reason why the link! (or the expensive link!) macro even have an implementation for non-Windows targets?

[matheo-lucak]

Do you have a minimal repro of what you're trying to accomplish? Keep in mind that the bindings for APIs are generated from metadata and I don't personally know much about WinRM or Linux. 😊

With this simple code, compiling on linux for linux target :
main.rs

fn main() {
    let mut handle: WSMAN_API_HANDLE = 0;
    unsafe {
        let result = WSManInitialize(WSMAN_FLAG_REQUESTED_API_VERSION_1_1, &mut handle);
        if result != 0 {
            panic!("Failed to initialize WSMan: {}", result);
        }
    }
    // Then we call other WSMan functions to create user, client, commands, etc..
}

cargo.toml

[package]
name = "wintest"
version = "0.1.0"
edition = "2021"

[dependencies]
windows-sys = { version = "0.59", features = ["Win32_System_RemoteManagement"] }

Compiling the program gives the linker error :

cargo r
   Compiling wintest v0.1.0 (/home/matska/Tests/wintest)
error: linking with `cc` failed: exit status: 1
  |
  = note: LC_ALL="C" PATH="/home/matska/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/bin:/home/matska/.cargo/bin:/home/matska/Utils/:/home/matska/Utils/dev-rust:/home/matska/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/wsl/lib:/mnt/c/Program Files (x86)/Common Files/Oracle/Java/java8path:/mnt/c/Program Files (x86)/Common Files/Oracle/Java/javapath:/mnt/c/Python39/Scripts/:/mnt/c/Python39/:/mnt/c/WINDOWS/system32:/mnt/c/WINDOWS:/mnt/c/WINDOWS/System32/Wbem:/mnt/c/WINDOWS/System32/WindowsPowerShell/v1.0/:/mnt/c/WINDOWS/System32/OpenSSH/:/mnt/c/Program Files/dotnet/:/mnt/c/ProgramData/chocolatey/bin:/mnt/c/Program Files/Git/cmd:/mnt/c/Users/m.lucak/.cargo/bin:/mnt/c/Users/m.lucak/AppData/Local/Microsoft/WindowsApps:/mnt/c/Program Files/JetBrains/RustRover 2024.2.2/bin:/mnt/c/Users/m.lucak/AppData/Local/Programs/Microsoft VS Code/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/usr/lib/rustup/bin" VSLANG="1033" "cc" "-m64" "/tmp/rustcJfC0Oo/symbols.o" "<8 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "/home/matska/Tests/wintest/target/debug/deps/{libwindows_sys-c4cb25bf3a48f262.rlib,libwindows_targets-7781b46b2bb04f6c.rlib}" "/home/matska/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/{libstd-1e40119a663b1e41.rlib,libpanic_unwind-c17245bd091354df.rlib,libobject-cd96b354c08fae15.rlib,libmemchr-65e636254baf89ab.rlib,libaddr2line-10dcc9a2e78b2b1e.rlib,libgimli-73aed197564ca365.rlib,librustc_demangle-6d92069f05504d6a.rlib,libstd_detect-3ddba380cdb712f3.rlib,libhashbrown-1c9b748326f090af.rlib,librustc_std_workspace_alloc-61109fcaa2782b03.rlib,libminiz_oxide-4f430c1ad3399055.rlib,libadler-396e0f8ad43d4281.rlib,libunwind-b3ec995576ac8387.rlib,libcfg_if-7a8d556bd2496467.rlib,liblibc-2cd05d129739cd79.rlib,liballoc-dcbc78300c47b651.rlib,librustc_std_workspace_core-3d3fdd80ec3c369e.rlib,libcore-919178916a309d3e.rlib,libcompiler_builtins-6497188c539eb018.rlib}" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "/home/matska/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/windows_x86_64_gnu-0.52.6/lib" "-L" "/home/matska/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/home/matska/Tests/wintest/target/debug/deps/wintest-7d3e2ea6b25c5dda" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs"
  = note: some arguments are omitted. use `--verbose` to show all linker arguments
  = note: /usr/sbin/ld: /home/matska/Tests/wintest/target/debug/deps/wintest-7d3e2ea6b25c5dda.dcly99qqef20d0ybzvnsfo9st.rcgu.o: in function `wintest::main':
          /home/matska/Tests/wintest/src/main.rs:8:(.text._ZN7wintest4main17h4f8b88528769695eE+0x1c): undefined reference to `WSManInitialize'
          collect2: error: ld returned 1 exit status

  = note: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
  = note: use the `-l` flag to specify native libraries to link
  = note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#rustc-link-lib)

error: could not compile `wintest` (bin "wintest") due to 1 previous error

And calling WSManInitialize uses the windows_targets::link! marco, which seems to use 'wsmsvc.dll' :

windows_targets::link!("wsmsvc.dll" "system" fn WSManInitialize(flags : u32, apihandle : *mut WSMAN_API_HANDLE) -> u32);

But indeed, as @tim-weis says, why is the link macro allows non-Windows platforms. It would mean there a way to link with .dll on linux ?

[kennykerr]

WSManInitialize is a Windows API implemented by the Windows operating system. It is documented as requiring Windows 8 or later.