eldritch horrors
f38ae92a38
add a reset() method to close the wrapped fd instead of assigning magic
constants. also make the from-fd constructor explicit so you can't
accidentally assign the *wrong* magic constant, or even an unrelated
integer that also just happens to be an fd by pure chance.
Change-Id: I51311b0f6e040240886b5103d39d1794a6acc325
129 lines
3.6 KiB
C++
129 lines
3.6 KiB
C++
#include <nlohmann/json.hpp>
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#include "remote-fs-accessor.hh"
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#include "nar-accessor.hh"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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namespace nix {
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RemoteFSAccessor::RemoteFSAccessor(ref<Store> store, const Path & cacheDir)
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: store(store)
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, cacheDir(cacheDir)
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{
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if (cacheDir != "")
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createDirs(cacheDir);
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}
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Path RemoteFSAccessor::makeCacheFile(std::string_view hashPart, const std::string & ext)
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{
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assert(cacheDir != "");
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return fmt("%s/%s.%s", cacheDir, hashPart, ext);
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}
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ref<FSAccessor> RemoteFSAccessor::addToCache(std::string_view hashPart, std::string && nar)
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{
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if (cacheDir != "") {
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try {
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/* FIXME: do this asynchronously. */
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writeFile(makeCacheFile(hashPart, "nar"), nar);
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} catch (...) {
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ignoreException();
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}
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}
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auto narAccessor = makeNarAccessor(std::move(nar));
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nars.emplace(hashPart, narAccessor);
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if (cacheDir != "") {
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try {
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nlohmann::json j = listNar(narAccessor, "", true);
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writeFile(makeCacheFile(hashPart, "ls"), j.dump());
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} catch (...) {
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ignoreException();
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}
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}
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return narAccessor;
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}
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std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path & path_, bool requireValidPath)
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{
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auto path = canonPath(path_);
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auto [storePath, restPath] = store->toStorePath(path);
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if (requireValidPath && !store->isValidPath(storePath))
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throw InvalidPath("path '%1%' is not a valid store path", store->printStorePath(storePath));
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auto i = nars.find(std::string(storePath.hashPart()));
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if (i != nars.end()) return {i->second, restPath};
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std::string listing;
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Path cacheFile;
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if (cacheDir != "" && pathExists(cacheFile = makeCacheFile(storePath.hashPart(), "nar"))) {
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try {
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listing = nix::readFile(makeCacheFile(storePath.hashPart(), "ls"));
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auto narAccessor = makeLazyNarAccessor(listing,
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[cacheFile](uint64_t offset, uint64_t length) {
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AutoCloseFD fd{open(cacheFile.c_str(), O_RDONLY | O_CLOEXEC)};
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if (!fd)
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throw SysError("opening NAR cache file '%s'", cacheFile);
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if (lseek(fd.get(), offset, SEEK_SET) != (off_t) offset)
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throw SysError("seeking in '%s'", cacheFile);
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std::string buf(length, 0);
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readFull(fd.get(), buf.data(), length);
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return buf;
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});
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nars.emplace(storePath.hashPart(), narAccessor);
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return {narAccessor, restPath};
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} catch (SysError &) { }
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try {
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auto narAccessor = makeNarAccessor(nix::readFile(cacheFile));
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nars.emplace(storePath.hashPart(), narAccessor);
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return {narAccessor, restPath};
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} catch (SysError &) { }
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}
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StringSink sink;
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store->narFromPath(storePath, sink);
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return {addToCache(storePath.hashPart(), std::move(sink.s)), restPath};
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}
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FSAccessor::Stat RemoteFSAccessor::stat(const Path & path)
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{
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auto res = fetch(path);
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return res.first->stat(res.second);
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}
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StringSet RemoteFSAccessor::readDirectory(const Path & path)
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{
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auto res = fetch(path);
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return res.first->readDirectory(res.second);
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}
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std::string RemoteFSAccessor::readFile(const Path & path, bool requireValidPath)
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{
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auto res = fetch(path, requireValidPath);
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return res.first->readFile(res.second);
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}
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std::string RemoteFSAccessor::readLink(const Path & path)
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{
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auto res = fetch(path);
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return res.first->readLink(res.second);
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}
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}
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