Is OpenSSL supported to be built as WebAssembly (wasm)?

[xb284524239]

My project uses the "openssl" crate.

When I use the command cargo build --lib --release --target x86_64-pc-windows-msvc, the build can be completed successfully.

However, when I use the command cargo build --lib --release --target wasm32-unknown-unknown, the build fails and prints the following error message:

PS C:\Workspace\VSCode_Workspace\payslip> cargo build --lib --release --target wasm32-unknown-unknown
    Blocking waiting for file lock on package cache
    Blocking waiting for file lock on package cache
   Compiling openssl-sys v0.9.104
   Compiling color_quant v1.1.0
   Compiling icu_properties_data v1.5.0
   Compiling unicode-ccc v0.4.0
   Compiling jpeg-decoder v0.3.1
   Compiling unicode-segmentation v1.12.0
   Compiling byteorder-lite v0.1.0
   Compiling i-slint-common v1.9.1
The following warnings were emitted during compilation:

warning: [email protected]: Could not find directory of OpenSSL installation, and this `-sys` crate cannot proceed without this knowledge. If OpenSSL is installed and this crate had trouble finding it,  you can set the `OPENSSL_DIR` environment variable for the compilation process. See stderr section below for further information.

error: failed to run custom build command for `openssl-sys v0.9.104`

Caused by:
  process didn't exit successfully: `C:\Workspace\VSCode_Workspace\payslip\target\release\build\openssl-sys-1b1cf58633c0b3ed\build-script-main` (exit code: 101)
  --- stdout
  cargo:rustc-check-cfg=cfg(osslconf, values("OPENSSL_NO_OCB", "OPENSSL_NO_SM4", "OPENSSL_NO_SEED", "OPENSSL_NO_CHACHA", "OPENSSL_NO_CAST", "OPENSSL_NO_IDEA", "OPENSSL_NO_CAMELLIA", "OPENSSL_NO_RC4", "OPENSSL_NO_BF", "OPENSSL_NO_PSK", "OPENSSL_NO_DEPRECATED_3_0", "OPENSSL_NO_SCRYPT", "OPENSSL_NO_SM3", "OPENSSL_NO_RMD160", "OPENSSL_NO_EC2M", "OPENSSL_NO_OCSP", "OPENSSL_NO_CMS", "OPENSSL_NO_COMP", "OPENSSL_NO_SOCK", "OPENSSL_NO_STDIO", "OPENSSL_NO_EC", "OPENSSL_NO_SSL3_METHOD", "OPENSSL_NO_KRB5", "OPENSSL_NO_TLSEXT", "OPENSSL_NO_SRP", "OPENSSL_NO_RFC3779", 
"OPENSSL_NO_SHA", "OPENSSL_NO_NEXTPROTONEG", "OPENSSL_NO_ENGINE", "OPENSSL_NO_BUF_FREELISTS"))
  cargo:rustc-check-cfg=cfg(openssl)
  cargo:rustc-check-cfg=cfg(libressl)
  cargo:rustc-check-cfg=cfg(boringssl)
  cargo:rustc-check-cfg=cfg(libressl250)
  cargo:rustc-check-cfg=cfg(libressl251)
  cargo:rustc-check-cfg=cfg(libressl252)
  cargo:rustc-check-cfg=cfg(libressl261)
  cargo:rustc-check-cfg=cfg(libressl270)
  cargo:rustc-check-cfg=cfg(libressl271)
  cargo:rustc-check-cfg=cfg(libressl273)
  cargo:rustc-check-cfg=cfg(libressl280)
  cargo:rustc-check-cfg=cfg(libressl281)
  cargo:rustc-check-cfg=cfg(libressl291)
  cargo:rustc-check-cfg=cfg(libressl310)
  cargo:rustc-check-cfg=cfg(libressl321)
  cargo:rustc-check-cfg=cfg(libressl332)
  cargo:rustc-check-cfg=cfg(libressl340)
  cargo:rustc-check-cfg=cfg(libressl350)
  cargo:rustc-check-cfg=cfg(libressl360)
  cargo:rustc-check-cfg=cfg(libressl361)
  cargo:rustc-check-cfg=cfg(libressl370)
  cargo:rustc-check-cfg=cfg(libressl380)
  cargo:rustc-check-cfg=cfg(libressl381)
  cargo:rustc-check-cfg=cfg(libressl382)
  cargo:rustc-check-cfg=cfg(libressl390)
  cargo:rustc-check-cfg=cfg(libressl400)
  cargo:rustc-check-cfg=cfg(ossl101)
  cargo:rustc-check-cfg=cfg(ossl102)
  cargo:rustc-check-cfg=cfg(ossl102f)
  cargo:rustc-check-cfg=cfg(ossl102h)
  cargo:rustc-check-cfg=cfg(ossl110)
  cargo:rustc-check-cfg=cfg(ossl110f)
  cargo:rustc-check-cfg=cfg(ossl110g)
  cargo:rustc-check-cfg=cfg(ossl110h)
  cargo:rustc-check-cfg=cfg(ossl111)
  cargo:rustc-check-cfg=cfg(ossl111b)
  cargo:rustc-check-cfg=cfg(ossl111c)
  cargo:rustc-check-cfg=cfg(ossl111d)
  cargo:rustc-check-cfg=cfg(ossl300)
  cargo:rustc-check-cfg=cfg(ossl310)
  cargo:rustc-check-cfg=cfg(ossl320)
  cargo:rustc-check-cfg=cfg(ossl330)
  cargo:rustc-check-cfg=cfg(ossl340)
  cargo:rerun-if-env-changed=WASM32_UNKNOWN_UNKNOWN_OPENSSL_LIB_DIR
  WASM32_UNKNOWN_UNKNOWN_OPENSSL_LIB_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_LIB_DIR
  OPENSSL_LIB_DIR unset
  cargo:rerun-if-env-changed=WASM32_UNKNOWN_UNKNOWN_OPENSSL_INCLUDE_DIR
  WASM32_UNKNOWN_UNKNOWN_OPENSSL_INCLUDE_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_INCLUDE_DIR
  OPENSSL_INCLUDE_DIR unset
  cargo:rerun-if-env-changed=WASM32_UNKNOWN_UNKNOWN_OPENSSL_DIR
  WASM32_UNKNOWN_UNKNOWN_OPENSSL_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_DIR
  OPENSSL_DIR unset
  cargo:rerun-if-env-changed=OPENSSL_NO_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_ALLOW_CROSS_wasm32-unknown-unknown
  cargo:rerun-if-env-changed=PKG_CONFIG_ALLOW_CROSS_wasm32_unknown_unknown
  cargo:rerun-if-env-changed=TARGET_PKG_CONFIG_ALLOW_CROSS
  cargo:rerun-if-env-changed=PKG_CONFIG_ALLOW_CROSS
  cargo:rerun-if-env-changed=PKG_CONFIG_wasm32-unknown-unknown
  cargo:rerun-if-env-changed=PKG_CONFIG_wasm32_unknown_unknown
  cargo:rerun-if-env-changed=TARGET_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_wasm32-unknown-unknown
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_wasm32_unknown_unknown
  cargo:rerun-if-env-changed=TARGET_PKG_CONFIG_SYSROOT_DIR
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR


  Could not find openssl via pkg-config:
  pkg-config has not been configured to support cross-compilation.

  Install a sysroot for the target platform and configure it via
  PKG_CONFIG_SYSROOT_DIR and PKG_CONFIG_PATH, or install a
  cross-compiling wrapper for pkg-config and set it via
  PKG_CONFIG environment variable.

  cargo:warning=Could not find directory of OpenSSL installation, and this `-sys` crate cannot proceed without this knowledge. If OpenSSL is installed and this crate had trouble finding it,  you can set the `OPENSSL_DIR` environment variable for the compilation process. See stderr section below for further information.

  --- stderr


  Could not find directory of OpenSSL installation, and this `-sys` crate cannot
  proceed without this knowledge. If OpenSSL is installed and this crate had
  trouble finding it,  you can set the `OPENSSL_DIR` environment variable for the
  compilation process.

  Make sure you also have the development packages of openssl installed.
  For example, `libssl-dev` on Ubuntu or `openssl-devel` on Fedora.

  If you're in a situation where you think the directory *should* be found
  automatically, please open a bug at https://github.com/sfackler/rust-openssl
  and include information about your system as well as this message.

  $HOST = x86_64-pc-windows-msvc
  $TARGET = wasm32-unknown-unknown
  openssl-sys = 0.9.104


warning: build failed, waiting for other jobs to finish...

[sfackler]

You'd need to build OpenSSL to target WASM and point openssl-sys to it. I don't know if that's possible or not.