libcurlwrapper

This library loads CURL from an Aroma Module instead of statically linking it to the binary. This results in a much smaller binary size (saves about 750KiB).

• Requires the CURLWrapperModule to be running via WUMSLoader.
• Requires wut for building.
• Use with curl 7.84.0 headers, other versions might not be compatible.
• See important changes in the Usage section.

Install via make install.

Usage

Make sure to define this in your Makefile:

WUMS_ROOT := $(DEVKITPRO)/wums

Use the normal curl headers, but link against -lcurlwrapper instead. For example replace -lcurl -lmbedtls -lmbedx509 -lmbedcrypto -lz with -lcurlwrapper.

If the CURLWrapperModule is not loaded curl_global_init will return a negative value.

Changes compared to normal CURL

libcurlwrapper tries to be a drop-in replacement for libcurl, but some things need to be considered.

All function are only available between calling curl_global_init and curl_global_cleanup.

Even functions like curl_version only work after calling curl_global_init.

Calling curl_easy_init will automatically add CA certificates.

It curl_easy_init returns success, curl_easy_setopt(curl, CURLOPT_CAINFO_BLOB, &blob); with current CA certificates will be called. These CA certificates are coming from the modules and can be updated in the future.

CURLOPT_SOCKOPTFUNCTION

• The CURLOPT_SOCKOPTFUNCTION callback requires a workaround to work properly.
• This is caused by setsockopt not being compatible with the sockets from the CURLWrapperModule.

Currently, there are two options to get the correct setsockopt function:

Option 1: CURLOPT_SOCKOPTDATA

• To get a pointer to the correct setsockopt function, you have to set the CURLOPT_SOCKOPTDATA to 0x13371337.
• The 0x13371337 will be replaced with a pointer to the correct setsockopt function.

Example:

static int initSocket(void *ptr, curl_socket_t socket, curlsocktype type) {    
  int r;
  // If ptr is not our magic value, it got replaced with a pointer to a valid setsockopt function.
  if ((uint32_t) ptr != 0x13371337) {
      r = reinterpret_cast<decltype(&setsockopt)>(ptr)(socket, SOL_SOCKET, SO_WINSCALE, &o, sizeof(o));
  } else {
      r = setsockopt(socket, SOL_SOCKET, SO_WINSCALE, &o, sizeof(o));
  }
   return r == 0 ? CURL_SOCKOPT_OK : CURL_SOCKOPT_ERROR;
}
[...]
// Set socktopt data to a magic value to get a pointer to the correct setsockopt function.
curl_easy_setopt(curl, CURLOPT_SOCKOPTDATA, 0x13371337);
curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, initSocket);

Downside of this option: the data pointer of CURLOPT_SOCKOPTFUNCTION can not be used.

Option 2: curlwrapper_setsockopt

This lib exposes the function curlwrapper_setsockopt which will call the correct function. Because this lib had no headers, you have to declare it in your app like this:

int curlwrapper_setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t optlen);

When using C++, you have to add extern "C" at the start.

Downside of this option: Linking to the original libcurl fails because curlwrapper_setsockopt is only defined in this wrapper lib.

Use this lib in Dockerfiles.

A prebuilt version of this lib can found on dockerhub. To use it for your projects, add this to your Dockerfile.

[...]
COPY --from=ghcr.io/wiiu-env/libcurlwrapper:[tag] /artifacts $DEVKITPRO
[...]

Replace [tag] with a tag you want to use, a list of tags can be found here. It's highly recommended to pin the version to the latest date instead of using latest.

Format the code via docker

docker run --rm -v ${PWD}:/src ghcr.io/wiiu-env/clang-format:13.0.0-2 -r ./source -i