wasmux/uapi/string/src/strerror.cpp.js

WebAssembly toolchain for compiling libc and kernel into system-level WASM modules

const fs = require("node:fs");
const path = require("node:path");

const { cxx } = require("bitmake");

module.exports = function(mk)
{
  const config = require(mk.SCRIPT_INPUT.toString());

  const unkErrorStr = "Unknown error";

  const errors = [];
  errors[config.success.code] = config.success.description;
  for (const {code, description} of Object.values(config.errors)) {
    errors[code] = description;
  }

  const lines = [];

  lines.push(cxx.generatedScriptNameComment(__filename));
  lines.push("");
  lines.push("#include <wasmux-config.h>");
  lines.push("#include <string.h>");
  lines.push("#include <errno.h>");
  lines.push("#include <wasmux/compiler.h>");
  lines.push("");
  lines.push(`static const char* s_errors[${errors.length}] =`);
  lines.push("{");

  for (let code = 0; code < errors.length; ++code) {
    const desc = errors[code] ? `"${errors[code]}"` : "nullptr";
    lines.push(`  ${desc},`);
  }

  lines.push("};");
  lines.push("");
  lines.push('extern "C" char* __strerror(int errnum)');
  lines.push("{");
  lines.push(`  if (errnum < ${errors.length} && s_errors[errnum]) {`);
  lines.push("    return const_cast<char*>(s_errors[errnum]);");
  lines.push("  }");
  lines.push(`  memcpy(__get_local_buffer_data(), "${unkErrorStr}", ${unkErrorStr.length + 1});`);
  /* TODO: Unknown error + atoi(errnum) */
  lines.push("  return __get_local_buffer_data();");
  lines.push("}");
  lines.push('extern "C" __ATTR_ALIAS(__strerror, strerror) __ATTR_WEAK;');
  lines.push("");

  fs.mkdirSync(path.dirname(mk.SCRIPT_OUTPUT.toString()), { recursive: true });
  fs.writeFileSync(mk.SCRIPT_OUTPUT.toString(), lines.join('\n'), "utf8");
}