Unable to link against third party library like openssl

[dscreve]

Running an SDK on a Mac.

I'm linking against libcrypto (openSSL) and it does not work.

I have installed libssl-dev in docker Image as below :
RUN apt update && apt -y install libssl-dev && apt -y clean

But I don't know how to tell him to add it in the generated SDK and I have the following error :
ld.lld: error: undefined symbol: RAND_bytes
(and many others for the all call to libcrypto).

I have openSSL installed on the Mac, and It seems to try to look in the Mac library :
ld.lld: warning: /opt/homebrew/Cellar/openssl@3/3.0.7/lib/libssl.a: archive member 'libssl-lib-bio_ssl.o' is neither ET_REL nor LLVM bitcode

How to fix this ?

[xtremekforever]

So my question is, how are you trying to link against libcrypto? Are you trying to use an -Xswiftc flag, or do you have it in your Package.swift as a systemLibrary?

[dscreve]

I have a systemLibrary :

  .systemLibrary(
        name: "OpenSSL",
        pkgConfig: "openssl",
        providers: [
            .apt(["openssl libssl-dev"]),
            .brew(["openssl"]),
        ])

[xtremekforever]

Okay, I did a little testing on my Linux system and found that if I include the pkgConfig: "openssl" line that swiftpm tries to look for -lssl on the host instead of in the target Swift SDK. So, if you remove that line, then it should start looking for libssl inside of the Swift SDK sysroot instead.

I didn't generate a Swift SDK with libssl-dev installed myself, but I got this result:

ld.lld: error: unable to find library -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Please give this a try!

[dscreve]

This works fine. But there somethings strange when compiling on the mac using the SDK.

When compiling C source code with SDK, it seems to use local header and not headers in SDK and does not conform to header search path.
For example, it uses /opt/local/include/openssl/ossl_typ.h instead of /opt/homebrew/Cellar/openssl@3/3.0.7/include/openssl/ossl_typ.h and not the file in the SDK.

[t089]

Try setting the pkg config search path. See here: #89 (comment)

[xtremekforever]

On my end in Linux, looks like setting these paths causes pkgconfig to work properly with the Swift SDK:

export PKG_CONFIG_SYSROOT_DIR=~/.swiftpm/swift
-sdks/6.0.3-RELEASE_ubuntu_jammy_aarch64.artifactbundle/6.0.3-RELEASE_ubuntu_jammy_aarch64/aarch64-unknown-linux-gnu/ubuntu-jammy.sdk
export PKG_CONFIG_PATH=$PKG_CONFIG_SYSROOT_DIR/usr/lib/aarch64-linux-gnu/pkgconfig

The only problem is that this seems like it's a lot of work to set these variables just for pkgconfig to point to the Swift SDK directory. I wonder if this should be moved into SwiftPM to automatically set these when a --swift-sdk is used...or has it been in some way? swiftlang/swift-package-manager#7472

[euanh]

The only problem is that this seems like it's a lot of work to set these variables just for pkgconfig to point to the Swift SDK directory. I wonder if this should be moved into SwiftPM to automatically set these when a --swift-sdk is used...or has it been in some way? swiftlang/swift-package-manager#7472

This is swiftlang/swift-package-manager#7409

[dscreve]

On my end in Linux, looks like setting these paths causes pkgconfig to work properly with the Swift SDK:

export PKG_CONFIG_SYSROOT_DIR=~/.swiftpm/swift
-sdks/6.0.3-RELEASE_ubuntu_jammy_aarch64.artifactbundle/6.0.3-RELEASE_ubuntu_jammy_aarch64/aarch64-unknown-linux-gnu/ubuntu-jammy.sdk
export PKG_CONFIG_PATH=$PKG_CONFIG_SYSROOT_DIR/usr/lib/aarch64-linux-gnu/pkgconfig

The only problem is that this seems like it's a lot of work to set these variables just for pkgconfig to point to the Swift SDK directory. I wonder if this should be moved into SwiftPM to automatically set these when a --swift-sdk is used...or has it been in some way? swiftlang/swift-package-manager#7472

This does not work when host is macOS. it still continues to use the macOS header : I use the function EVP_MD_get_type() which is declared in ubuntu-jammy.sdk/usr/include/openssl/evp.h but it tried to open /usr/local/include/openssl/evp.h on macOS, which does not contains declaration. It seems to ignore openssl.pc configuration.