lix/src/libfetchers/tarball.cc

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#include "fetchers.hh"
#include "cache.hh"
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#include "filetransfer.hh"
#include "globals.hh"
#include "store-api.hh"
#include "archive.hh"
#include "tarfile.hh"
namespace nix::fetchers {
DownloadFileResult downloadFile(
ref<Store> store,
const std::string & url,
const std::string & name,
bool immutable)
{
// FIXME: check store
Attrs inAttrs({
{"type", "file"},
{"url", url},
{"name", name},
});
auto cached = getCache()->lookupExpired(store, inAttrs);
auto useCached = [&]() -> DownloadFileResult
{
return {
.storePath = std::move(cached->storePath),
.etag = getStrAttr(cached->infoAttrs, "etag"),
.effectiveUrl = getStrAttr(cached->infoAttrs, "url")
};
};
if (cached && !cached->expired)
return useCached();
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FileTransferRequest request(url);
if (cached)
request.expectedETag = getStrAttr(cached->infoAttrs, "etag");
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FileTransferResult res;
try {
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res = getFileTransfer()->download(request);
} catch (FileTransferError & e) {
if (cached) {
warn("%s; using cached version", e.msg());
return useCached();
} else
throw;
}
// FIXME: write to temporary file.
Attrs infoAttrs({
{"etag", res.etag},
{"url", res.effectiveUri},
});
std::optional<StorePath> storePath;
if (res.cached) {
assert(cached);
assert(request.expectedETag == res.etag);
storePath = std::move(cached->storePath);
} else {
StringSink sink;
dumpString(*res.data, sink);
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auto hash = hashString(HashType::SHA256, *res.data);
ValidPathInfo info(store->makeFixedOutputPath(FileIngestionMethod::Flat, hash, name));
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info.narHash = hashString(HashType::SHA256, *sink.s);
info.narSize = sink.s->size();
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info.ca = FileSystemHash {
.method = FileIngestionMethod::Flat,
.hash = hash,
};
auto source = StringSource { *sink.s };
store->addToStore(info, source, NoRepair, NoCheckSigs);
storePath = std::move(info.path);
}
getCache()->add(
store,
inAttrs,
infoAttrs,
*storePath,
immutable);
if (url != res.effectiveUri)
getCache()->add(
store,
{
{"type", "file"},
{"url", res.effectiveUri},
{"name", name},
},
infoAttrs,
*storePath,
immutable);
return {
.storePath = std::move(*storePath),
.etag = res.etag,
.effectiveUrl = res.effectiveUri,
};
}
Tree downloadTarball(
ref<Store> store,
const std::string & url,
const std::string & name,
bool immutable)
{
Attrs inAttrs({
{"type", "tarball"},
{"url", url},
{"name", name},
});
auto cached = getCache()->lookupExpired(store, inAttrs);
if (cached && !cached->expired)
return Tree {
.actualPath = store->toRealPath(cached->storePath),
.storePath = std::move(cached->storePath),
.info = TreeInfo {
.lastModified = getIntAttr(cached->infoAttrs, "lastModified"),
},
};
auto res = downloadFile(store, url, name, immutable);
std::optional<StorePath> unpackedStorePath;
time_t lastModified;
if (cached && res.etag != "" && getStrAttr(cached->infoAttrs, "etag") == res.etag) {
unpackedStorePath = std::move(cached->storePath);
lastModified = getIntAttr(cached->infoAttrs, "lastModified");
} else {
Path tmpDir = createTempDir();
AutoDelete autoDelete(tmpDir, true);
unpackTarfile(store->toRealPath(res.storePath), tmpDir);
auto members = readDirectory(tmpDir);
if (members.size() != 1)
throw nix::Error("tarball '%s' contains an unexpected number of top-level files", url);
auto topDir = tmpDir + "/" + members.begin()->name;
lastModified = lstat(topDir).st_mtime;
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unpackedStorePath = store->addToStore(name, topDir, FileIngestionMethod::Recursive, HashType::SHA256, defaultPathFilter, NoRepair);
}
Attrs infoAttrs({
{"lastModified", lastModified},
{"etag", res.etag},
});
getCache()->add(
store,
inAttrs,
infoAttrs,
*unpackedStorePath,
immutable);
return Tree {
.actualPath = store->toRealPath(*unpackedStorePath),
.storePath = std::move(*unpackedStorePath),
.info = TreeInfo {
.lastModified = lastModified,
},
};
}
struct TarballInput : Input
{
ParsedURL url;
std::optional<Hash> hash;
TarballInput(const ParsedURL & url) : url(url)
{ }
std::string type() const override { return "tarball"; }
bool operator ==(const Input & other) const override
{
auto other2 = dynamic_cast<const TarballInput *>(&other);
return
other2
&& to_string() == other2->to_string()
&& hash == other2->hash;
}
bool isImmutable() const override
{
return hash || narHash;
}
ParsedURL toURL() const override
{
auto url2(url);
// NAR hashes are preferred over file hashes since tar/zip files
// don't have a canonical representation.
if (narHash)
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url2.query.insert_or_assign("narHash", narHash->to_string(Base::SRI));
else if (hash)
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url2.query.insert_or_assign("hash", hash->to_string(Base::SRI));
return url2;
}
Attrs toAttrsInternal() const override
{
Attrs attrs;
attrs.emplace("url", url.to_string());
if (hash)
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attrs.emplace("hash", hash->to_string(Base::SRI));
return attrs;
}
std::pair<Tree, std::shared_ptr<const Input>> fetchTreeInternal(nix::ref<Store> store) const override
{
auto tree = downloadTarball(store, url.to_string(), "source", false);
auto input = std::make_shared<TarballInput>(*this);
input->narHash = store->queryPathInfo(tree.storePath)->narHash;
return {std::move(tree), input};
}
};
struct TarballInputScheme : InputScheme
{
std::unique_ptr<Input> inputFromURL(const ParsedURL & url) override
{
if (url.scheme != "file" && url.scheme != "http" && url.scheme != "https") return nullptr;
if (!hasSuffix(url.path, ".zip")
&& !hasSuffix(url.path, ".tar")
&& !hasSuffix(url.path, ".tar.gz")
&& !hasSuffix(url.path, ".tar.xz")
&& !hasSuffix(url.path, ".tar.bz2"))
return nullptr;
auto input = std::make_unique<TarballInput>(url);
auto hash = input->url.query.find("hash");
if (hash != input->url.query.end()) {
// FIXME: require SRI hash.
input->hash = Hash(hash->second);
input->url.query.erase(hash);
}
auto narHash = input->url.query.find("narHash");
if (narHash != input->url.query.end()) {
// FIXME: require SRI hash.
input->narHash = Hash(narHash->second);
input->url.query.erase(narHash);
}
return input;
}
std::unique_ptr<Input> inputFromAttrs(const Attrs & attrs) override
{
if (maybeGetStrAttr(attrs, "type") != "tarball") return {};
for (auto & [name, value] : attrs)
if (name != "type" && name != "url" && name != "hash")
throw Error("unsupported tarball input attribute '%s'", name);
auto input = std::make_unique<TarballInput>(parseURL(getStrAttr(attrs, "url")));
if (auto hash = maybeGetStrAttr(attrs, "hash"))
// FIXME: require SRI hash.
input->hash = Hash(*hash);
return input;
}
};
static auto r1 = OnStartup([] { registerInputScheme(std::make_unique<TarballInputScheme>()); });
}