101 lines
4.1 KiB
Markdown
101 lines
4.1 KiB
Markdown
[](https://github.com/wiiu-env/libcurlwrapper/actions/workflows/push_image.yml)
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# libcurlwrapper
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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).
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- Requires the [CURLWrapperModule](https://github.com/wiiu-env/CURLWrapperModule) to be running via [WUMSLoader](https://github.com/wiiu-env/WUMSLoader).
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- Requires [wut](https://github.com/devkitPro/wut) for building.
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- Use with curl 7.84.0 headers, other versions might not be compatible.
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- See important changes in the Usage section.
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Install via `make install`.
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## Usage
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Make sure to define this in your Makefile:
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```
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WUMS_ROOT := $(DEVKITPRO)/wums
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```
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Use the normal curl headers, but link against `-lcurlwrapper` instead. For example replace `-lcurl -lmbedtls -lmbedx509 -lmbedcrypto -lz` with `-lcurlwrapper`.
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**If the CURLWrapperModule is not loaded `curl_global_init` will return a negative value.**
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## Changes compared to normal CURL
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libcurlwrapper tries to be a drop-in replacement for libcurl, but some things need to be considered.
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### All function are only available between calling `curl_global_init` and `curl_global_cleanup`.
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Even functions like `curl_version` only work after calling `curl_global_init`.
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### Calling `curl_easy_init` will automatically add CA certificates.
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It `curl_easy_init` returns success, `curl_easy_setopt(curl, CURLOPT_CAINFO_BLOB, &blob);` with current CA certificates will be called.
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These CA certificates are coming from the modules and can be updated in the future.
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### CURLOPT_SOCKOPTFUNCTION
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- The `CURLOPT_SOCKOPTFUNCTION` callback requires a workaround to work properly.
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- This is caused by `setsockopt` not being compatible with the sockets from the CURLWrapperModule.
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Currently, there are two options to get the correct `setsockopt` function:
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#### Option 1: CURLOPT_SOCKOPTDATA
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- To get a pointer to the correct `setsockopt` function, you have to set the `CURLOPT_SOCKOPTDATA` to 0x13371337.
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- The `0x13371337` will be replaced with a pointer to the correct `setsockopt` function.
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Example:
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```C
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static int initSocket(void *ptr, curl_socket_t socket, curlsocktype type) {
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int r;
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// If ptr is not our magic value, it got replaced with a pointer to a valid setsockopt function.
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if ((uint32_t) ptr != 0x13371337) {
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r = reinterpret_cast<decltype(&setsockopt)>(ptr)(socket, SOL_SOCKET, SO_WINSCALE, &o, sizeof(o));
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} else {
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r = setsockopt(socket, SOL_SOCKET, SO_WINSCALE, &o, sizeof(o));
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}
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return r == 0 ? CURL_SOCKOPT_OK : CURL_SOCKOPT_ERROR;
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}
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[...]
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// Set socktopt data to a magic value to get a pointer to the correct setsockopt function.
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curl_easy_setopt(curl, CURLOPT_SOCKOPTDATA, 0x13371337);
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curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, initSocket);
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```
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Downside of this option: the data pointer of `CURLOPT_SOCKOPTFUNCTION` can not be used.
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#### Option 2: curlwrapper_setsockopt
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This lib exposes the function `curlwrapper_setsockopt` which will call the correct function. Because this lib had no headers, you have to
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declare it in your app like this:
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````C
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int curlwrapper_setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t optlen);
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````
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When using C++, you have to add `extern "C"` at the start.
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Downside of this option: Linking to the original libcurl fails because `curlwrapper_setsockopt` is only defined in this wrapper lib.
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## Use this lib in Dockerfiles.
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A prebuilt version of this lib can found on dockerhub. To use it for your projects, add this to your Dockerfile.
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```
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[...]
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COPY --from=ghcr.io/wiiu-env/libcurlwrapper:[tag] /artifacts $DEVKITPRO
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[...]
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```
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Replace [tag] with a tag you want to use, a list of tags can be found [here](https://github.com/wiiu-env/libcurlwrapper/pkgs/container/libcurlwrapper/versions).
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It's highly recommended to pin the version to the **latest date** instead of using `latest`.
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## Format the code via docker
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`docker run --rm -v ${PWD}:/src ghcr.io/wiiu-env/clang-format:13.0.0-2 -r ./source -i`
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