CODEWITHSUNDEEP
rustcygwingnu
mattmc
mattmc

Reputation: 479

Linking NTDLL in Rust application using Cygwin while targeting x86_64-pc-windows-gnu

I opened a pull request in DarkEld3r's os_info repository to retrieve the actual Windows version and edition name.

The application needs to link to ntdll.dll in order to use RtlGetVersion(). The DLL is linked correctly when the target is set to x86_64-pc-windows-msvc while using Cygwin and the normal Windows console. When the target is x86_64-pc-windows-gnu, the linker returns an error:

   Running `rustc --crate-name print_version examples\print_version.rs --crate-type bin --emit=dep-info,link -C debuginfo=2 -C metadata=ec9720acb7c740b3 -C extra-filename=-ec9720acb7c740b3 --out-dir C:\projects\os-info\target\debug\examples -L dependency=C:\projects\os-info\target\debug\deps --extern kernel32=C:\projects\os-info\target\debug\deps\libkernel32-beacffc979f26c46.rlib --extern user32=C:\projects\os-info\target\debug\deps\libuser32-fbb28ae30109687c.rlib --extern winapi=C:\projects\os-info\target\debug\deps\libwinapi-bb7af3f2a31ea235.rlib --extern os_info=C:\projects\os-info\target\debug\deps\libos_info-c5887b186deb8679.rlib`
error: linking with `gcc` failed: exit code: 1
  |
  = note: "gcc" "-Wl,--enable-long-section-names" "-fno-use-linker-plugin" "-Wl,--nxcompat" "-nostdlib" "-m64" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\crt2.o" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\rsbegin.o" "-L" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version0.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version1.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version10.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version11.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version12.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version2.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version3.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version4.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version5.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version6.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version7.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version8.rust-cgu.o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.print_version9.rust-cgu.o" "-o" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.exe" "C:\\projects\\os-info\\target\\debug\\examples\\print_version-ec9720acb7c740b3.crate.allocator.rust-cgu.o" "-Wl,--gc-sections" "-nodefaultlibs" "-L" "C:\\projects\\os-info\\target\\debug\\deps" "-L" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib" "-Wl,-Bstatic" "C:\\projects\\os-info\\target\\debug\\deps\\libos_info-c5887b186deb8679.rlib" "C:\\projects\\os-info\\target\\debug\\deps\\libkernel32-beacffc979f26c46.rlib" "C:\\projects\\os-info\\target\\debug\\deps\\libuser32-fbb28ae30109687c.rlib" "C:\\projects\\os-info\\target\\debug\\deps\\libwinapi-bb7af3f2a31ea235.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libstd-60d4a252bdda9250.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libpanic_unwind-0b63e20460046692.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libunwind-7daa32005d584d8a.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\liblibc-49ff25caaa6e945f.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\liballoc_system-a05404e5e059417a.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\liballoc-f824a78e715239af.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libstd_unicode-2abaea46f194a6e1.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\librand-81cbf6f1d5a19206.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libcore-f2bd2d524c6ace24.rlib" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\libcompiler_builtins-c6139fac5e899293.rlib" "-Wl,-Bdynamic" "-l" "ntdll" "-l" "kernel32" "-l" "user32" "-l" "advapi32" "-l" "ws2_32" "-l" "userenv" "-l" "shell32" "-Wl,-Bstatic" "-l" "gcc_eh" "-l" "pthread" "-Wl,-Bdynamic" "-lmingwex" "-lmingw32" "-lgcc" "-lmsvcrt" "-luser32" "-lkernel32" "C:\\Users\\appveyor\\.rustup\\toolchains\\stable-x86_64-pc-windows-gnu\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib\\rsend.o"
  = note: ld: cannot find -lntdll

NTDLL.DLL is linked on line 12 of this file.

I haven't found any questions regarding linking to NTDLL. I found How do I specify the linker path in Rust?, but that solution didn't work for me either. I found the "libntdll.a" library in the /usr/lib/w32api directory of Cygwin, but it seems like GCC isn't using it.

Is there any way to get this to work on Windows while targeting GNU, or am I forced to use the MSVC target when linking system DLLs?

Upvotes: 3

Views: 1125

Answers (2)

AldaronLau
AldaronLau

Reputation: 1194

The ntdll.dll file is not on the path by default for the GNU windows target, so you can add it by writing the following in a build.rs file:

fn main() {
    println!(r"cargo:rustc-link-search=C:\windows\system32");
}

Upvotes: 0

mattmc
mattmc

Reputation: 479

I figured out how to do it by looking at the winapi crate repository.

Since, 0.2.8 of the crate doesn't support the RtlGetVersion() DLL function, I had to include libntdll.a in the repo. Once that's was done, I had to create a custom build script to include the source path of the library.

```

/// build.rs
/// Run custom functionality when a build executes
fn main() {
    use std::env::var;
    use std::path::Path;

    // When targeting x86_64-pc-windows-gnu, we need to include the DLL libraries
    // found in the lib/x86_64 directory
    if var("TARGET").map(|target| target == "x86_64-pc-windows-gnu").unwrap_or(false) {
        let dir = var("CARGO_MANIFEST_DIR").unwrap();
        println!("cargo:rustc-link-search=native={}", Path::new(&dir).join("lib/x86_64").display());
    }

    // When targeting i686-pc-windows-gnu, we need to include the DLL libraries
    // found in the lib/i686 directory
    if var("TARGET").map(|target| target == "i686-pc-windows-gnu").unwrap_or(false) {
        let dir = var("CARGO_MANIFEST_DIR").unwrap();
        println!("cargo:rustc-link-search=native={}", Path::new(&dir).join("lib/i686").display());
    }
}

```

Upvotes: 2

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