Build libnixutil with MinGW

Co-Authored-By volth <volth@volth.com>

Makefile

@@ -1,11 +1,16 @@
 -include Makefile.config
 clean-files += Makefile.config
 
+include mk/platform.mk
+
 ifeq ($(ENABLE_BUILD), yes)
 makefiles = \
   mk/precompiled-headers.mk \
   local.mk \
-  src/libutil/local.mk \
+  src/libutil/local.mk
+
+ifdef HOST_UNIX
+makefiles += \
   src/libstore/local.mk \
   src/libfetchers/local.mk \
   src/libmain/local.mk \
@@ -23,22 +28,28 @@ makefiles = \
   doc/manual/local.mk \
   doc/internal-api/local.mk
 endif
+endif
 
 ifeq ($(ENABLE_BUILD)_$(ENABLE_TESTS), yes_yes)
 UNIT_TEST_ENV = _NIX_TEST_UNIT_DATA=unit-test-data
 makefiles += \
-  src/libutil/tests/local.mk \
+  src/libutil/tests/local.mk
+ifdef HOST_UNIX
+makefiles += \
   src/libstore/tests/local.mk \
   src/libexpr/tests/local.mk
 endif
+endif
 
 ifeq ($(ENABLE_TESTS), yes)
+ifdef HOST_UNIX
 makefiles += \
   tests/functional/local.mk \
   tests/functional/ca/local.mk \
   tests/functional/dyn-drv/local.mk \
   tests/functional/test-libstoreconsumer/local.mk \
   tests/functional/plugins/local.mk
+endif
 else
 makefiles += \
   mk/disable-tests.mk

mk/lib.mk

@@ -12,38 +12,7 @@ man-pages :=
 install-tests :=
 install-tests-groups :=
 
-ifdef HOST_OS
-  HOST_KERNEL = $(firstword $(subst -, ,$(HOST_OS)))
-  ifeq ($(patsubst mingw%,,$(HOST_KERNEL)),)
-    HOST_MINGW = 1
-    HOST_WINDOWS = 1
-  endif
-  ifeq ($(HOST_KERNEL), cygwin)
-    HOST_CYGWIN = 1
-    HOST_WINDOWS = 1
-    HOST_UNIX = 1
-  endif
-  ifeq ($(patsubst darwin%,,$(HOST_KERNEL)),)
-    HOST_DARWIN = 1
-    HOST_UNIX = 1
-  endif
-  ifeq ($(patsubst freebsd%,,$(HOST_KERNEL)),)
-    HOST_FREEBSD = 1
-    HOST_UNIX = 1
-  endif
-  ifeq ($(patsubst netbsd%,,$(HOST_KERNEL)),)
-    HOST_NETBSD = 1
-    HOST_UNIX = 1
-  endif
-  ifeq ($(HOST_KERNEL), linux)
-    HOST_LINUX = 1
-    HOST_UNIX = 1
-  endif
-  ifeq ($(patsubst solaris%,,$(HOST_KERNEL)),)
-    HOST_SOLARIS = 1
-    HOST_UNIX = 1
-  endif
-endif
+include mk/platform.mk
 
 # Hack to define a literal space.
 space :=

mk/platform.mk

@@ -0,0 +1,32 @@
+ifdef HOST_OS
+  HOST_KERNEL = $(firstword $(subst -, ,$(HOST_OS)))
+  ifeq ($(patsubst mingw%,,$(HOST_KERNEL)),)
+    HOST_MINGW = 1
+    HOST_WINDOWS = 1
+  endif
+  ifeq ($(HOST_KERNEL), cygwin)
+    HOST_CYGWIN = 1
+    HOST_WINDOWS = 1
+    HOST_UNIX = 1
+  endif
+  ifeq ($(patsubst darwin%,,$(HOST_KERNEL)),)
+    HOST_DARWIN = 1
+    HOST_UNIX = 1
+  endif
+  ifeq ($(patsubst freebsd%,,$(HOST_KERNEL)),)
+    HOST_FREEBSD = 1
+    HOST_UNIX = 1
+  endif
+  ifeq ($(patsubst netbsd%,,$(HOST_KERNEL)),)
+    HOST_NETBSD = 1
+    HOST_UNIX = 1
+  endif
+  ifeq ($(HOST_KERNEL), linux)
+    HOST_LINUX = 1
+    HOST_UNIX = 1
+  endif
+  ifeq ($(patsubst solaris%,,$(HOST_KERNEL)),)
+    HOST_SOLARIS = 1
+    HOST_UNIX = 1
+  endif
+endif

src/libutil/ambient-authority.cc

@@ -1,5 +1,4 @@
 #include "ambient-authority.hh"
-#include "namespaces.hh"
 #include "util.hh"
 #include "finally.hh"
 #include "file-system.hh"
@@ -14,9 +13,12 @@
 # include <mutex>
 # include <sys/resource.h>
 # include "cgroup.hh"
+# include "namespaces.hh"
 #endif
 
-#include <sys/mount.h>
+#ifndef _WIN32
+# include <sys/mount.h>
+#endif
 
 namespace nix {
 
@@ -70,9 +72,13 @@ void setStackSize(size_t stackSize)
 
 void restoreProcessContext(bool restoreMounts)
 {
+    #ifndef _WIN32
     restoreSignals();
+    #endif
     if (restoreMounts) {
+        #if __linux__
         restoreMountNamespace();
+        #endif
     }
 
     #if __linux__

src/libutil/archive.cc

@@ -17,6 +17,12 @@
 #include "file-system.hh"
 #include "signals.hh"
 
+#if _WIN32
+# include <fileapi.h>
+# include "windows-file-path.hh"
+# include "windows-error.hh"
+#endif
+
 namespace nix {
 
 struct ArchiveSettings : Config
@@ -218,11 +224,13 @@ static void parse(ParseSink & sink, Source & source, const Path & path)
             sink.closeRegularFile();
         }
 
+#ifndef _WIN32
         else if (s == "executable" && type == tpRegular) {
             auto s = readString(source);
             if (s != "") throw badArchive("executable marker has non-empty value");
             sink.isExecutable();
         }
+#endif
 
         else if (s == "entry" && type == tpDirectory) {
             std::string name, prevName;

src/libutil/args.cc

@@ -6,7 +6,9 @@
 #include "users.hh"
 #include "json-utils.hh"
 
-#include <glob.h>
+#ifndef _WIN32
+# include <glob.h>
+#endif
 
 namespace nix {
 
@@ -345,6 +347,7 @@ Args::Flag Args::Flag::mkHashTypeOptFlag(std::string && longName, std::optional<
 static void _completePath(AddCompletions & completions, std::string_view prefix, bool onlyDirs)
 {
     completions.setType(Completions::Type::Filenames);
+    #ifndef _WIN32
     glob_t globbuf;
     int flags = GLOB_NOESCAPE;
     #ifdef GLOB_ONLYDIR
@@ -362,6 +365,7 @@ static void _completePath(AddCompletions & completions, std::string_view prefix,
         }
     }
     globfree(&globbuf);
+    #endif
 }
 
 void Args::completePath(AddCompletions & completions, size_t, std::string_view prefix)

src/libutil/environment-variables.cc

@@ -32,18 +32,4 @@ std::map<std::string, std::string> getEnv()
     return env;
 }
 
-
-void clearEnv()
-{
-    for (auto & name : getEnv())
-        unsetenv(name.first.c_str());
-}
-
-void replaceEnv(const std::map<std::string, std::string> & newEnv)
-{
-    clearEnv();
-    for (auto & newEnvVar : newEnv)
-        setenv(newEnvVar.first.c_str(), newEnvVar.second.c_str(), 1);
-}
-
 }

src/libutil/error.cc

@@ -17,7 +17,7 @@ void BaseError::addTrace(std::shared_ptr<AbstractPos> && e, hintformat hint, boo
 
 void throwExceptionSelfCheck(){
     // This is meant to be caught in initLibUtil()
-    throw SysError("C++ exception handling is broken. This would appear to be a problem with the way Nix was compiled and/or linked and/or loaded.");
+    throw Error("C++ exception handling is broken. This would appear to be a problem with the way Nix was compiled and/or linked and/or loaded.");
 }
 
 // c++ std::exception descendants must have a 'const char* what()' function.

src/libutil/error.hh

@@ -200,27 +200,66 @@ MakeError(Error, BaseError);
 MakeError(UsageError, Error);
 MakeError(UnimplementedError, Error);
 
+/**
+ * To use in catch-blocks.
+ */
 class SysError : public Error
 {
 public:
-    int errNo;
+    /**
+     * Has to be big enough for all platforms:
+     *
+     * - Unix: `int` (perhaps `int32_t`)
+     * - Windows: `DWORD` (which is `uint32_t`)
+     *
+     * The smallest type which contains all valeus of both is `int64_t`.
+     */
+    int64_t errNo;
 
     template<typename... Args>
-    SysError(int errNo_, const Args & ... args)
-        : Error("")
+    SysError(int64_t errNo, const Args & ... args)
+        : Error(args...), errNo(errNo)
+    {  }
+};
+
+/**
+ * To throw. Don't catch this in portable code! Catch `SysError`
+ * instead.
+ */
+class PosixError : public SysError
+{
+public:
+    template<typename... Args>
+    PosixError(int errNo, const Args & ... args)
+        : SysError(errNo, "")
     {
-        errNo = errNo_;
         auto hf = hintfmt(args...);
         err.msg = hintfmt("%1%: %2%", normaltxt(hf.str()), strerror(errNo));
     }
 
     template<typename... Args>
-    SysError(const Args & ... args)
-        : SysError(errno, args ...)
+    PosixError(const Args & ... args)
+        : PosixError(errno, args ...)
     {
     }
 };
 
+#ifdef _WIN32
+class WinError;
+#endif
+
+/**
+ * Convenience alias for when we use a `errno`-based error handling
+ * function on Unix, and a Win32 on on Windows.
+ */
+typedef
+#ifdef _WIN32
+    WinError
+#else
+    PosixError
+#endif
+    NativeSysError;
+
 /** Throw an exception for the purpose of checking that exception handling works; see 'initLibUtil()'.
  */
 void throwExceptionSelfCheck();