WIP local store on Windows

Fixes NixOS#10558

maintainers/flake-module.nix

@@ -241,17 +241,17 @@
         ''^src/libstore/unix/build/worker\.hh$''
         ''^src/libstore/unix/builtins/fetchurl\.cc$''
         ''^src/libstore/unix/builtins/unpack-channel\.cc$''
-        ''^src/libstore/unix/gc\.cc$''
+        ''^src/libstore/gc\.cc$''
         ''^src/libstore/unix/local-overlay-store\.cc$''
         ''^src/libstore/unix/local-overlay-store\.hh$''
-        ''^src/libstore/unix/local-store\.cc$''
-        ''^src/libstore/unix/local-store\.hh$''
+        ''^src/libstore/local-store\.cc$''
+        ''^src/libstore/local-store\.hh$''
         ''^src/libstore/unix/lock\.cc$''
         ''^src/libstore/unix/lock\.hh$''
-        ''^src/libstore/unix/optimise-store\.cc$''
+        ''^src/libstore/optimise-store\.cc$''
         ''^src/libstore/unix/pathlocks\.cc$''
-        ''^src/libstore/unix/posix-fs-canonicalise\.cc$''
-        ''^src/libstore/unix/posix-fs-canonicalise\.hh$''
+        ''^src/libstore/posix-fs-canonicalise\.cc$''
+        ''^src/libstore/posix-fs-canonicalise\.hh$''
         ''^src/libstore/uds-remote-store\.cc$''
         ''^src/libstore/uds-remote-store\.hh$''
         ''^src/libstore/windows/build\.cc$''

src/libfetchers/cache.cc

@@ -109,7 +109,7 @@ struct CacheImpl : Cache
         Key key,
         Store & store,
         Attrs value,
-        const StorePath & storePath)
+        const StorePath & storePath) override
     {
         /* Add the store prefix to the cache key to handle multiple
            store prefixes. */

src/libstore/unix/gc.cc → src/libstore/gc.cc

@@ -19,18 +19,18 @@
 #include <climits>
 #include <errno.h>
 #include <fcntl.h>
-#include <poll.h>
-#include <sys/socket.h>
 #include <sys/stat.h>
-#include <sys/statvfs.h>
+#ifndef _WIN32
+# include <poll.h>
+# include <sys/statvfs.h>
+# include <sys/socket.h>
+# include <sys/un.h>
+#endif
 #include <sys/types.h>
-#include <sys/un.h>
 #include <unistd.h>
 
 namespace nix {
 
-using namespace nix::unix;
-
 static std::string gcSocketPath = "/gc-socket/socket";
 static std::string gcRootsDir = "gcroots";
 
@@ -64,7 +64,7 @@ void LocalStore::createTempRootsFile()
         /* Check whether the garbage collector didn't get in our
            way. */
         struct stat st;
-        if (fstat(fdTempRoots->get(), &st) == -1)
+        if (fstat(fromDescriptorReadOnly(fdTempRoots->get()), &st) == -1)
             throw SysError("statting '%1%'", fnTempRoots);
         if (st.st_size == 0) break;
 
@@ -108,7 +108,7 @@ void LocalStore::addTempRoot(const StorePath & path)
             debug("connecting to '%s'", socketPath);
             *fdRootsSocket = createUnixDomainSocket();
             try {
-                nix::connect(fdRootsSocket->get(), socketPath);
+                nix::connect(toSocket(fdRootsSocket->get()), socketPath);
             } catch (SysError & e) {
                 /* The garbage collector may have exited or not
                    created the socket yet, so we need to restart. */
@@ -166,12 +166,16 @@ void LocalStore::findTempRoots(Roots & tempRoots, bool censor)
             // those to keep the directory alive.
             continue;
         }
-        Path path = i.path();
+        Path path = i.path().string();
 
         pid_t pid = std::stoi(name);
 
         debug("reading temporary root file '%1%'", path);
-        AutoCloseFD fd(open(path.c_str(), O_CLOEXEC | O_RDWR, 0666));
+        AutoCloseFD fd(toDescriptor(open(path.c_str(),
+#ifndef _WIN32
+            O_CLOEXEC |
+#endif
+            O_RDWR, 0666)));
         if (!fd) {
             /* It's okay if the file has disappeared. */
             if (errno == ENOENT) continue;
@@ -240,8 +244,7 @@ void LocalStore::findRoots(const Path & path, std::filesystem::file_type type, R
                         unlink(path.c_str());
                     }
                 } else {
-                    struct stat st2 = lstat(target);
-                    if (!S_ISLNK(st2.st_mode)) return;
+                    if (!std::filesystem::is_symlink(target)) return;
                     Path target2 = readLink(target);
                     if (isInStore(target2)) foundRoot(target, target2);
                 }
@@ -299,22 +302,20 @@ Roots LocalStore::findRoots(bool censor)
 
 typedef std::unordered_map<Path, std::unordered_set<std::string>> UncheckedRoots;
 
-static void readProcLink(const std::string & file, UncheckedRoots & roots)
+static void readProcLink(const std::filesystem::path & file, UncheckedRoots & roots)
 {
-    constexpr auto bufsiz = PATH_MAX;
-    char buf[bufsiz];
-    auto res = readlink(file.c_str(), buf, bufsiz);
-    if (res == -1) {
-        if (errno == ENOENT || errno == EACCES || errno == ESRCH)
+    std::filesystem::path buf;
+    try {
+        buf = std::filesystem::read_symlink(file);
+    } catch (std::filesystem::filesystem_error & e) {
+        if (e.code() == std::errc::no_such_file_or_directory
+                || e.code() == std::errc::permission_denied
+                || e.code() == std::errc::no_such_process)
             return;
-        throw SysError("reading symlink");
+        throw;
     }
-    if (res == bufsiz) {
-        throw Error("overly long symlink starting with '%1%'", std::string_view(buf, bufsiz));
-    }
-    if (res > 0 && buf[0] == '/')
-        roots[std::string(static_cast<char *>(buf), res)]
-            .emplace(file);
+    if (buf.is_absolute())
+        roots[std::move(buf).string()].emplace(file);
 }
 
 static std::string quoteRegexChars(const std::string & raw)
@@ -490,6 +491,10 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
     createDirs(dirOf(socketPath));
     auto fdServer = createUnixDomainSocket(socketPath, 0666);
 
+    // TODO nonblocking socket on windows?
+#ifdef _WIN32
+    throw UnimplementedError("External GC client not implemented yet");
+#else
     if (fcntl(fdServer.get(), F_SETFL, fcntl(fdServer.get(), F_GETFL) | O_NONBLOCK) == -1)
         throw SysError("making socket '%1%' non-blocking", socketPath);
 
@@ -590,6 +595,8 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
         if (serverThread.joinable()) serverThread.join();
     });
 
+#endif
+
     /* Find the roots.  Since we've grabbed the GC lock, the set of
        permanent roots cannot increase now. */
     printInfo("finding garbage collector roots...");
@@ -623,7 +630,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
            by another process. We need to be sure that we can acquire an
            exclusive lock before deleting them. */
         if (baseName.find("tmp-", 0) == 0) {
-            AutoCloseFD tmpDirFd = open(realPath.c_str(), O_RDONLY | O_DIRECTORY);
+            AutoCloseFD tmpDirFd = openDirectory(realPath);
             if (tmpDirFd.get() == -1 || !lockFile(tmpDirFd.get(), ltWrite, false)) {
                 debug("skipping locked tempdir '%s'", realPath);
                 return;

src/libstore/unix/local-store.cc → src/libstore/local-store.cc

@@ -26,34 +26,34 @@
 #include <new>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/select.h>
 #include <sys/time.h>
 #include <unistd.h>
 #include <utime.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <stdio.h>
 #include <time.h>
-#include <grp.h>
+
+#ifndef _WIN32
+# include <grp.h>
+#endif
 
 #if __linux__
-#include <sched.h>
-#include <sys/statvfs.h>
-#include <sys/mount.h>
-#include <sys/ioctl.h>
+# include <sched.h>
+# include <sys/statvfs.h>
+# include <sys/mount.h>
+# include <sys/ioctl.h>
 #endif
 
 #ifdef __CYGWIN__
-#include <windows.h>
+# include <windows.h>
 #endif
 
 #include <sqlite3.h>
 
 
 namespace nix {
 
-using namespace nix::unix;
-
 std::string LocalStoreConfig::doc()
 {
     return
@@ -224,6 +224,7 @@ LocalStore::LocalStore(const Params & params)
         }
     }
 
+#ifndef _WIN32
     /* Optionally, create directories and set permissions for a
        multi-user install. */
     if (isRootUser() && settings.buildUsersGroup != "") {
@@ -245,6 +246,7 @@ LocalStore::LocalStore(const Params & params)
             }
         }
     }
+#endif
 
     /* Ensure that the store and its parents are not symlinks. */
     if (!settings.allowSymlinkedStore) {
@@ -270,14 +272,25 @@ LocalStore::LocalStore(const Params & params)
         if (stat(reservedPath.c_str(), &st) == -1 ||
             st.st_size != settings.reservedSize)
         {
-            AutoCloseFD fd = open(reservedPath.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600);
+            AutoCloseFD fd = toDescriptor(open(reservedPath.c_str(), O_WRONLY | O_CREAT
+#ifndef _WIN32
+                | O_CLOEXEC
+#endif
+                , 0600));
             int res = -1;
 #if HAVE_POSIX_FALLOCATE
             res = posix_fallocate(fd.get(), 0, settings.reservedSize);
 #endif
             if (res == -1) {
                 writeFull(fd.get(), std::string(settings.reservedSize, 'X'));
-                [[gnu::unused]] auto res2 = ftruncate(fd.get(), settings.reservedSize);
+                [[gnu::unused]] auto res2 =
+
+#ifdef _WIN32
+                    SetEndOfFile(fd.get())
+#else
+                    ftruncate(fd.get(), settings.reservedSize)
+#endif
+                    ;
             }
         }
     } catch (SystemError & e) { /* don't care about errors */
@@ -460,10 +473,14 @@ LocalStore::LocalStore(std::string scheme, std::string path, const Params & para
 AutoCloseFD LocalStore::openGCLock()
 {
     Path fnGCLock = stateDir + "/gc.lock";
-    auto fdGCLock = open(fnGCLock.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0600);
+    auto fdGCLock = open(fnGCLock.c_str(), O_RDWR | O_CREAT
+#ifndef _WIN32
+        | O_CLOEXEC
+#endif
+        , 0600);
     if (!fdGCLock)
         throw SysError("opening global GC lock '%1%'", fnGCLock);
-    return fdGCLock;
+    return toDescriptor(fdGCLock);
 }
 
 
@@ -491,7 +508,7 @@ LocalStore::~LocalStore()
     try {
         auto fdTempRoots(_fdTempRoots.lock());
         if (*fdTempRoots) {
-            *fdTempRoots = -1;
+            *fdTempRoots = INVALID_DESCRIPTOR;
             unlink(fnTempRoots.c_str());
         }
     } catch (...) {
@@ -969,11 +986,13 @@ void LocalStore::registerValidPath(const ValidPathInfo & info)
 
 void LocalStore::registerValidPaths(const ValidPathInfos & infos)
 {
+#ifndef _WIN32
     /* SQLite will fsync by default, but the new valid paths may not
        be fsync-ed.  So some may want to fsync them before registering
        the validity, at the expense of some speed of the path
        registering operation. */
     if (settings.syncBeforeRegistering) sync();
+#endif
 
     return retrySQLite<void>([&]() {
         auto state(_state.lock());
@@ -1155,7 +1174,7 @@ void LocalStore::addToStore(const ValidPathInfo & info, Source & source,
 
             autoGC();
 
-            canonicalisePathMetaData(realPath, {});
+            canonicalisePathMetaData(realPath);
 
             optimisePath(realPath, repair); // FIXME: combine with hashPath()
 
@@ -1307,7 +1326,7 @@ StorePath LocalStore::addToStoreFromDump(
                 narHash = narSink.finish();
             }
 
-            canonicalisePathMetaData(realPath, {}); // FIXME: merge into restorePath
+            canonicalisePathMetaData(realPath); // FIXME: merge into restorePath
 
             optimisePath(realPath, repair);
 
@@ -1340,8 +1359,8 @@ std::pair<std::filesystem::path, AutoCloseFD> LocalStore::createTempDirInStore()
            the GC between createTempDir() and when we acquire a lock on it.
            We'll repeat until 'tmpDir' exists and we've locked it. */
         tmpDirFn = createTempDir(realStoreDir, "tmp");
-        tmpDirFd = open(tmpDirFn.c_str(), O_RDONLY | O_DIRECTORY);
-        if (tmpDirFd.get() < 0) {
+        tmpDirFd = openDirectory(tmpDirFn);
+        if (!tmpDirFd) {
             continue;
         }
         lockedByUs = lockFile(tmpDirFd.get(), ltWrite, true);
@@ -1390,19 +1409,16 @@ bool LocalStore::verifyStore(bool checkContents, RepairFlag repair)
         for (auto & link : readDirectory(linksDir)) {
             auto name = link.path().filename();
             printMsg(lvlTalkative, "checking contents of '%s'", name);
-            Path linkPath = linksDir / name;
             PosixSourceAccessor accessor;
             std::string hash = hashPath(
-                {getFSSourceAccessor(), CanonPath(linkPath)},
+                PosixSourceAccessor::createAtRoot(link.path()),
                 FileIngestionMethod::Recursive, HashAlgorithm::SHA256).to_string(HashFormat::Nix32, false);
             if (hash != name.string()) {
                 printError("link '%s' was modified! expected hash '%s', got '%s'",
-                    linkPath, name, hash);
+                    link.path(), name, hash);
                 if (repair) {
-                    if (unlink(linkPath.c_str()) == 0)
-                        printInfo("removed link '%s'", linkPath);
-                    else
-                        throw SysError("removing corrupt link '%s'", linkPath);
+                    std::filesystem::remove(link.path());
+                    printInfo("removed link '%s'", link.path());
                 } else {
                     errors = true;
                 }
@@ -1583,8 +1599,12 @@ static void makeMutable(const Path & path)
     /* The O_NOFOLLOW is important to prevent us from changing the
        mutable bit on the target of a symlink (which would be a
        security hole). */
-    AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
-    if (fd == -1) {
+    AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_NOFOLLOW
+#ifndef _WIN32
+        | O_CLOEXEC
+#endif
+        );
+    if (fd == INVALID_DESCRIPTOR) {
         if (errno == ELOOP) return; // it's a symlink
         throw SysError("opening file '%1%'", path);
     }

src/libstore/unix/local-store.hh → src/libstore/local-store.hh

@@ -32,7 +32,9 @@ struct OptimiseStats
 {
     unsigned long filesLinked = 0;
     uint64_t bytesFreed = 0;
+#ifndef _WIN32
     uint64_t blocksFreed = 0;
+#endif
 };
 
 struct LocalStoreConfig : virtual LocalFSStoreConfig

src/libstore/local.mk

@@ -89,11 +89,11 @@ else
   endif
 endif
 
-$(d)/unix/local-store.cc: $(d)/unix/schema.sql.gen.hh $(d)/unix/ca-specific-schema.sql.gen.hh
+$(d)/local-store.cc: $(d)/schema.sql.gen.hh $(d)/ca-specific-schema.sql.gen.hh
 
 $(d)/unix/build.cc:
 
-clean-files += $(d)/unix/schema.sql.gen.hh $(d)/unix/ca-specific-schema.sql.gen.hh
+clean-files += $(d)/schema.sql.gen.hh $(d)/ca-specific-schema.sql.gen.hh
 
 $(eval $(call install-file-in, $(buildprefix)$(d)/nix-store.pc, $(libdir)/pkgconfig, 0644))