path: root/third_party/nix/src/libstore/builtins/fetchurl.cc

#include <absl/strings/match.h>
#include <glog/logging.h>

#include "libstore/builtins.hh"
#include "libstore/download.hh"
#include "libstore/store-api.hh"
#include "libutil/archive.hh"
#include "libutil/compression.hh"

namespace nix {

void builtinFetchurl(const BasicDerivation& drv, const std::string& netrcData) {
  /* Make the host's netrc data available. Too bad curl requires
     this to be stored in a file. It would be nice if we could just
     pass a pointer to the data. */
  if (netrcData != "") {
    settings.netrcFile = "netrc";
    writeFile(settings.netrcFile, netrcData, 0600);
  }

  auto getAttr = [&](const std::string& name) {
    auto i = drv.env.find(name);
    if (i == drv.env.end())
      throw Error(format("attribute '%s' missing") % name);
    return i->second;
  };

  Path storePath = getAttr("out");
  auto mainUrl = getAttr("url");
  bool unpack = get(drv.env, "unpack", "") == "1";

  /* Note: have to use a fresh downloader here because we're in
     a forked process. */
  auto downloader = makeDownloader();

  auto fetch = [&](const std::string& url) {
    auto source = sinkToSource([&](Sink& sink) {
      /* No need to do TLS verification, because we check the hash of
         the result anyway. */
      DownloadRequest request(url);
      request.verifyTLS = false;
      request.decompress = false;

      auto decompressor = makeDecompressionSink(
          unpack && absl::EndsWith(mainUrl, ".xz") ? "xz" : "none", sink);
      downloader->download(std::move(request), *decompressor);
      decompressor->finish();
    });

    if (unpack)
      restorePath(storePath, *source);
    else
      writeFile(storePath, *source);

    auto executable = drv.env.find("executable");
    if (executable != drv.env.end() && executable->second == "1") {
      if (chmod(storePath.c_str(), 0755) == -1)
        throw SysError(format("making '%1%' executable") % storePath);
    }
  };

  /* Try the hashed mirrors first. */
  if (getAttr("outputHashMode") == "flat") {
    auto hash_ = Hash::deserialize(getAttr("outputHash"),
                                   parseHashType(getAttr("outputHashAlgo")));
    if (hash_.ok()) {
      auto h = *hash_;
      for (auto hashedMirror : settings.hashedMirrors.get()) {
        try {
          if (!absl::EndsWith(hashedMirror, "/")) {
            hashedMirror += '/';
          }
          fetch(hashedMirror + printHashType(h.type) + "/" +
                h.to_string(Base16, false));
          return;
        } catch (Error& e) {
          LOG(ERROR) << e.what();
        }
      }
    } else {
      LOG(ERROR) << "checking mirrors for '" << mainUrl
                 << "': " << hash_.status().ToString();
    }
  }

  /* Otherwise try the specified URL. */
  fetch(mainUrl);
}

}  // namespace nix