Move from shipping the initrd to generating it during install.

.pipelines/build-stage.yml

@@ -23,7 +23,7 @@ parameters:
   - name: targets
     type: object
     default:
-      - target: "wsl;libwsl;wslg;wslservice;wslhost;wslrelay;wslinstaller;wslinstall;initramfs;wslserviceproxystub;wslsettings;wslinstallerproxystub;testplugin"
+      - target: "wsl;libwsl;wslg;wslservice;wslhost;wslrelay;wslinstaller;wslinstall;init;wslserviceproxystub;wslsettings;wslinstallerproxystub;testplugin"
         pattern: "wsl.exe,libwsl.dll,wslg.exe,wslservice.exe,wslhost.exe,wslrelay.exe,wslinstaller.exe,wslinstall.dll,wslserviceproxystub.dll,wslsettings/wslsettings.dll,wslsettings/wslsettings.exe,wslinstallerproxystub.dll,wsldevicehost.dll,WSLDVCPlugin.dll,testplugin.dll,wsldeps.dll"
       - target: "msixgluepackage"
         pattern: "gluepackage.msix"

CMakeLists.txt

@@ -66,7 +66,6 @@ find_nuget_package(Microsoft.WSL.bsdtar BSDTARD /build/native/bin)
 find_nuget_package(Microsoft.WSL.LinuxSdk LINUXSDK /)
 find_nuget_package(Microsoft.WSL.TestDistro TEST_DISTRO /)
 find_nuget_package(Microsoft.WSLg WSLG /build/native/bin)
-find_nuget_package(StrawberryPerl PERL /)
 find_nuget_package(vswhere VSWHERE /tools)
 find_nuget_package(Wix WIX /tools/net6.0/any)
 
@@ -92,7 +91,6 @@ find_nuget_package(Microsoft.Windows.SDK.NET.Ref WINDOWS_SDK_DOTNET /)
 find_nuget_package(Microsoft.Xaml.Behaviors.WinUI.Managed XAML_BEHAVIORS /)
 find_nuget_package(WinUIEx WINUIEX /)
 
-set(BIN2CPIO ${CMAKE_CURRENT_LIST_DIR}/tools/bin2cpio/bin2cpio.pl)
 set(WSLG_TS_PLUGIN_DLL "WSLDVCPlugin.dll")
 
 # Default to debug build if unspecified

msipackage/CMakeLists.txt

@@ -22,7 +22,7 @@ foreach(binary ${WINDOWS_BINARIES})
     list(APPEND BINARIES_DEPENDENCIES "${PACKAGE_INPUT_DIR}/${binary}")
 endforeach()
 
-set(LINUX_BINARIES init;initrd.img)
+set(LINUX_BINARIES init)
 foreach(binary ${LINUX_BINARIES})
     list(APPEND BINARIES_DEPENDENCIES "${BIN}/${binary}")
 endforeach()
@@ -52,7 +52,7 @@ add_custom_command(
 
 add_custom_target(msipackage DEPENDS ${OUTPUT_PACKAGE})
 set_target_properties(msipackage PROPERTIES EXCLUDE_FROM_ALL FALSE SOURCES ${PACKAGE_WIX_IN})
-add_dependencies(msipackage wsl wslg wslservice wslhost wslrelay wslserviceproxystub init initramfs wslinstall msixgluepackage)
+add_dependencies(msipackage wsl wslg wslservice wslhost wslrelay wslserviceproxystub init wslinstall msixgluepackage)
 
 if (WSL_BUILD_WSL_SETTINGS)
     add_dependencies(msipackage wslsettings libwsl)

msipackage/package.wix.in

@@ -1,4 +1,4 @@
-<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
+<Wix xmlns="http://wixtoolset.org/schemas/v4/wxs">
     <Package Name="Windows Subsystem for Linux" Language="1033" InstallerVersion="500" Version="${PACKAGE_VERSION}" Manufacturer="Microsoft Corporation" UpgradeCode="6D5B792B-1EDC-4DE9-8EAD-201B820F8E82" Scope="perMachine" Compressed="${COMPRESS_PACKAGE}">
         <MajorUpgrade AllowDowngrades="yes"  Disallow="no"  />
         <MediaTemplate EmbedCab="yes" />
@@ -261,7 +261,6 @@
         <DirectoryRef Id="TOOLSFOLDER">
             <Component Id="tools" Guid="F0C8D6BA-1502-41E7-BF72-D93DFA134733" Bitness="always64" UninstallWhenSuperseded="yes">
                 <File Id="init" Source="${BIN}/init" Checksum="yes" />
-                <File Id="initrd.img" Source="${BIN}/initrd.img"/>
                 <File Id="bsdtar" Source="${BSDTARD_SOURCE_DIR}/${TARGET_PLATFORM}/bsdtar"/>
 
                 <?if "${WSL_DEV_BINARY_PATH}" = "" ?>
@@ -461,7 +460,23 @@
             Return="check"
             Execute="deferred"
          />
-
+
+        <CustomAction Id="CreateInitrd"
+            Impersonate="no"
+            BinaryRef="wslinstall.dll"
+            DllEntry="CreateInitrd"
+            Return="check"
+            Execute="deferred"
+         />
+
+        <CustomAction Id="RemoveInitrd"
+            Impersonate="no"
+            BinaryRef="wslinstall.dll"
+            DllEntry="RemoveInitrd"
+            Return="check"
+            Execute="deferred"
+         />
+
          <CustomAction Id="RemoveRegistryKeyProtections"
             Impersonate="no"
             BinaryRef="wslinstall.dll"
@@ -525,10 +540,17 @@
             <!-- This needs to run after the registry is written because this action needs to read the install path -->
             <Custom Action="RegisterLspCategories" After="WriteRegistryValues" Condition='((not REMOVE~="ALL") or WIX_UPGRADE_DETECTED)  and (not UPGRADINGPRODUCTCODE) and (not SKIPLSP = 1)' />
 
+            <!-- Generate initrd.img from the init binary during installation -->
+            <Custom Action="CreateInitrd" After="RegisterLspCategories" Condition='((not REMOVE~="ALL") or WIX_UPGRADE_DETECTED) and (not UPGRADINGPRODUCTCODE)' />
+
             <!-- This needs to run before the registry is cleared because this action needs to read the install path.
                  This actions runs on uninstallation and upgrade. -->
             <Custom Action="UnregisterLspCategories" Before="RemoveRegistryValues" Condition='(REMOVE~="ALL") and (not UPGRADINGPRODUCTCODE) and (not SKIPLSP = 1)' />
 
+            <!-- This needs to run before the registry is cleared because this action needs to read the install path.
+                 This actions runs on uninstallation and upgrade. -->
+            <Custom Action="RemoveInitrd" Before="UnregisterLspCategories" Condition='(REMOVE~="ALL") and (not UPGRADINGPRODUCTCODE)' />
+
             <?if "${WSL_BUILD_WSL_SETTINGS}" = "true" ?>
                 <!-- This needs to run before the registry is written because this action calculates registry key names and values -->
                 <Custom Action="CalculateWslSettingsProtocolIds" Before="WriteRegistryValues" Condition='(not REMOVE~="ALL")' />

packages.config

@@ -24,7 +24,6 @@
   <package id="Microsoft.WSL.TestDistro" version="2.5.7-47" />
   <package id="Microsoft.WSLg" version="1.0.73" />
   <package id="Microsoft.Xaml.Behaviors.WinUI.Managed" version="3.0.0" />
-  <package id="StrawberryPerl" version="5.32.1.1" />
   <package id="vswhere" version="3.1.7" />
   <package id="WinUIEx" version="2.9.0" />
   <package id="Wix" version="5.0.2" />

src/linux/init/CMakeLists.txt

@@ -50,21 +50,4 @@ set(INIT_LIBRARIES ${COMMON_LINUX_LINK_LIBRARIES} netlinkutil plan9 mountutil co
 add_linux_executable(init "${SOURCES}" "${HEADERS}" "${INIT_LIBRARIES}")
 add_dependencies(init localization)
 
-set(INITRAMFS ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${CMAKE_BUILD_TYPE}/initrd.img)
-set(INIT ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${CMAKE_BUILD_TYPE}/init)
-
-# The initramfs depends on both the init target and binary so it doesn't start too early
-# (before the symbols are stripped from the init binary)
-# but so that it is still rebuilt if the file itself changes.
-add_custom_command(
-    OUTPUT ${INITRAMFS} "${CMAKE_CURRENT_BINARY_DIR}/CmakeFiles/initramfs"
-    DEPENDS init ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${CMAKE_BUILD_TYPE}/init
-    COMMAND ${PERL_SOURCE_DIR}/bin/perl.exe ${BIN2CPIO} ${INIT} ${INITRAMFS}
-    COMMAND ${CMAKE_COMMAND} -E touch "${CMAKE_CURRENT_BINARY_DIR}/CmakeFiles/initramfs"
-    VERBATIM
-    )
-
-add_custom_target(initramfs DEPENDS ${INITRAMFS})
-
 set_target_properties(init PROPERTIES FOLDER linux)
-set_target_properties(initramfs PROPERTIES FOLDER linux)

src/windows/service/exe/WslCoreVm.cpp

@@ -166,7 +166,7 @@ void WslCoreVm::Initialize(const GUID& VmId, const wil::shared_handle& UserToken
     // Set the install path of the package.
     m_installPath = wsl::windows::common::wslutil::GetBasePath();
 
-    // Initialize the path to the tools folder.
+    // Initialize the path to the tools folder which also serves as the default rootfs path.
     m_rootFsPath = m_installPath / LXSS_TOOLS_DIRECTORY;
 
     // Store the path of the user profile.

src/windows/wslinstall/DllMain.cpp

@@ -42,6 +42,12 @@ static constexpr auto c_wslSettingsProgIDPropertyName = L"WSLSETTINGSPROGID";
         return NOERROR; \
     }
 
+#define WSL_INSTALL_LOG(Name, ...) \
+    { \
+        WSL_LOG(Name, __VA_ARGS__); \
+        WriteInstallLog(std::format("MSI install: {}", Name)); \
+    }
+
 #ifndef WSL_OFFICIAL_BUILD
 void TrustPackageCertificate(LPCWSTR Path)
 {
@@ -519,8 +525,7 @@ extern "C" UINT __stdcall CleanMsixState(MSIHANDLE install)
 extern "C" UINT __stdcall DeprovisionMsix(MSIHANDLE install)
 try
 {
-    WSL_LOG("DeprovisionMsix");
-    WriteInstallLog("MSI install: DeprovisionMsix");
+    WSL_INSTALL_LOG("DeprovisionMsix");
 
     const winrt::Windows::Management::Deployment::PackageManager packageManager;
     const auto result = packageManager.DeprovisionPackageForAllUsersAsync(wsl::windows::common::wslutil::c_msixPackageFamilyName).get();
@@ -543,8 +548,7 @@ catch (...)
 extern "C" UINT __stdcall RemoveMsixAsSystem(MSIHANDLE install)
 try
 {
-    WSL_LOG("RemoveMsixAsSystem");
-    WriteInstallLog("MSI install: RemoveMsixAsSystem");
+    WSL_INSTALL_LOG("RemoveMsixAsSystem");
 
     const winrt::Windows::Management::Deployment::PackageManager packageManager;
 
@@ -573,8 +577,7 @@ catch (...)
 extern "C" UINT __stdcall RemoveMsixAsUser(MSIHANDLE install)
 try
 {
-    WSL_LOG("RemoveMsixAsUser");
-    WriteInstallLog("MSI install: RemoveMsixAsUser");
+    WSL_INSTALL_LOG("RemoveMsixAsUser");
 
     const winrt::Windows::Management::Deployment::PackageManager packageManager;
 
@@ -643,8 +646,7 @@ wsl::windows::common::filesystem::TempFile ExtractMsix(MSIHANDLE install)
 extern "C" UINT __stdcall InstallMsixAsUser(MSIHANDLE install)
 try
 {
-    WSL_LOG("InstallMsixAsUser");
-    WriteInstallLog("MSI install: InstallMsixAsUser");
+    WSL_INSTALL_LOG("InstallMsixAsUser");
 
     // RegisterPackageByFamilyNameAsync() cannot be run as SYSTEM.
     //  If this thread runs as SYSTEM, simply skip this step.
@@ -687,8 +689,7 @@ try
     // Release a file handle to the MSIX file so that it can be installed.
     msixFile.Handle.reset();
 
-    WSL_LOG("InstallMsix", TraceLoggingValue(msixFile.Path.c_str(), "Path"));
-    WriteInstallLog("MSI install: InstallMsix");
+    WSL_INSTALL_LOG("InstallMsix", TraceLoggingValue(msixFile.Path.c_str(), "Path"));
 
     winrt::Windows::Management::Deployment::PackageManager packageManager;
 
@@ -790,8 +791,7 @@ extern "C" UINT __stdcall WslFinalizeInstallation(MSIHANDLE install)
 {
     try
     {
-        WSL_LOG("WslFinalizeInstallation");
-        WriteInstallLog(std::format("MSI install: WslFinalizeInstallation"));
+        WSL_INSTALL_LOG("WslFinalizeInstallation");
     }
     CATCH_LOG();
 
@@ -801,9 +801,7 @@ extern "C" UINT __stdcall WslFinalizeInstallation(MSIHANDLE install)
 extern "C" UINT __stdcall WslValidateInstallation(MSIHANDLE install)
 try
 {
-    WSL_LOG("WslValidateInstallation");
-
-    WriteInstallLog(std::format("MSI install: WslValidateInstallation"));
+    WSL_INSTALL_LOG("WslValidateInstallation");
 
     // TODO: Use a more precise version check so we don't install if the Windows build doesn't support lifted.
 
@@ -874,6 +872,157 @@ extern "C" UINT __stdcall UnregisterLspCategories(MSIHANDLE install)
     return NOERROR;
 }
 
+void CreateCpioInitrd(_In_ const std::filesystem::path& SourcePath, _In_ const std::filesystem::path& DestPath)
+{
+    // Open the source init binary
+    wil::unique_hfile sourceFile{
+        CreateFileW(SourcePath.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr)};
+    THROW_LAST_ERROR_IF(!sourceFile);
+
+    // Get file size
+    LARGE_INTEGER fileSize{};
+    THROW_IF_WIN32_BOOL_FALSE(GetFileSizeEx(sourceFile.get(), &fileSize));
+    THROW_HR_IF(E_INVALIDARG, fileSize.HighPart != 0); // File too large
+
+    const DWORD initSize = fileSize.LowPart;
+    const auto initDataPadding = (4 - (initSize % 4)) % 4;
+    wil::unique_hfile destFile{CreateFileW(DestPath.c_str(), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr)};
+    THROW_LAST_ERROR_IF(!destFile);
+
+    // Clean up the destination file on failure.
+    auto deleteFile = wil::scope_exit_log(WI_DIAGNOSTICS_INFO, [&] {
+        destFile.reset();
+        LOG_IF_WIN32_BOOL_FALSE(DeleteFileW(DestPath.c_str()));
+    });
+
+    auto writeCpioHeader = [&destFile](DWORD fileSize, PCSTR name) {
+        // CPIO newc header: magic(6) + 13 fields of 8 hex chars each = 110 bytes
+        constexpr size_t headerSize = 110;
+        const auto nameLen = strlen(name) + 1;
+        const auto headerPadding = (4 - ((headerSize + nameLen) % 4)) % 4;
+
+        // Get current time for mtime
+        const auto mtime = static_cast<DWORD>(time(nullptr));
+
+        char header[headerSize + 1];
+        sprintf_s(
+            header,
+            "070701" // magic
+            "%08X"   // inode
+            "%08X"   // mode
+            "%08X"   // uid
+            "%08X"   // gid
+            "%08X"   // nlink
+            "%08X"   // mtime
+            "%08X"   // filesize
+            "%08X"   // devmajor
+            "%08X"   // devminor
+            "%08X"   // rdevmajor
+            "%08X"   // rdevminor
+            "%08X"   // namesize
+            "%08X",  // check
+            0,
+            (fileSize > 0) ? 0100755 : 0,
+            0,
+            0,
+            (fileSize > 0) ? 1 : 0,
+            mtime,
+            fileSize,
+            0,
+            0,
+            0,
+            0,
+            static_cast<DWORD>(nameLen),
+            0);
+
+        DWORD bytesWritten;
+        THROW_IF_WIN32_BOOL_FALSE(WriteFile(destFile.get(), header, headerSize, &bytesWritten, nullptr));
+
+        // Write name with null terminator
+        THROW_IF_WIN32_BOOL_FALSE(WriteFile(destFile.get(), name, static_cast<DWORD>(nameLen), &bytesWritten, nullptr));
+
+        // Write padding to align to 4 bytes
+        if (headerPadding > 0)
+        {
+            char padding[4] = {0};
+            THROW_IF_WIN32_BOOL_FALSE(WriteFile(destFile.get(), padding, static_cast<DWORD>(headerPadding), &bytesWritten, nullptr));
+        }
+    };
+
+    // Write init file header
+    writeCpioHeader(initSize, SourcePath.filename().string().c_str());
+
+    // Copy file contents
+    wsl::windows::common::relay::InterruptableRelay(sourceFile.get(), destFile.get(), nullptr, 64 * 1024);
+
+    // Write data padding
+    if (initDataPadding > 0)
+    {
+        char padding[4] = {0};
+        DWORD bytesWritten;
+        THROW_IF_WIN32_BOOL_FALSE(WriteFile(destFile.get(), padding, static_cast<DWORD>(initDataPadding), &bytesWritten, nullptr));
+    }
+
+    // Write trailer entry (empty file with name "TRAILER!!!")
+    writeCpioHeader(0, "TRAILER!!!");
+
+    // Pad the archive to 512-byte boundary
+    constexpr DWORD archiveBlockSize = 512;
+    LARGE_INTEGER currentPos{};
+    THROW_IF_WIN32_BOOL_FALSE(SetFilePointerEx(destFile.get(), {}, &currentPos, FILE_CURRENT));
+
+    const auto archivePadding = (archiveBlockSize - (currentPos.LowPart % archiveBlockSize)) % archiveBlockSize;
+    if (archivePadding > 0)
+    {
+        auto paddingBuffer = std::make_unique<char[]>(archivePadding);
+        memset(paddingBuffer.get(), 0, archivePadding);
+        DWORD bytesWritten;
+        THROW_IF_WIN32_BOOL_FALSE(WriteFile(destFile.get(), paddingBuffer.get(), archivePadding, &bytesWritten, nullptr));
+    }
+
+    deleteFile.release();
+}
+
+extern "C" UINT __stdcall CreateInitrd(MSIHANDLE install)
+try
+{
+    WSL_INSTALL_LOG("CreateInitrd");
+
+    const auto installRoot = wsl::windows::common::wslutil::GetMsiPackagePath();
+    THROW_HR_IF(E_INVALIDARG, !installRoot.has_value());
+
+    const auto toolsPath = std::filesystem::path(installRoot.value()) / LXSS_TOOLS_DIRECTORY;
+    const auto initPath = toolsPath / L"init";
+    const auto initrdPath = toolsPath / LXSS_VM_MODE_INITRD_NAME;
+    CreateCpioInitrd(initPath, initrdPath);
+
+    return NOERROR;
+}
+catch (...)
+{
+    LOG_CAUGHT_EXCEPTION();
+
+    return ERROR_INSTALL_FAILURE;
+}
+
+extern "C" UINT __stdcall RemoveInitrd(MSIHANDLE install)
+{
+    try
+    {
+        WSL_INSTALL_LOG("RemoveInitrd");
+
+        const auto installRoot = wsl::windows::common::wslutil::GetMsiPackagePath();
+        THROW_HR_IF(E_INVALIDARG, !installRoot.has_value());
+
+        const auto initrdPath = std::filesystem::path(installRoot.value()) / LXSS_TOOLS_DIRECTORY / LXSS_VM_MODE_INITRD_NAME;
+        THROW_IF_WIN32_BOOL_FALSE(DeleteFileW(initrdPath.c_str()));
+    }
+    CATCH_LOG()
+
+    // Failures in this method aren't fatal.
+    return NOERROR;
+}
+
 std::wstring GetWslSettingsInstalledExePath(MSIHANDLE install)
 {
     const auto wslSettingsInstallFolder = GetMsiProperty(install, c_wslSettingsInstalledDirectoryPropertyName);

src/windows/wslinstall/wslinstall.def

@@ -4,6 +4,8 @@ EXPORTS
     CleanExplorerState
     CleanMsixState
     DeprovisionMsix
+    CreateInitrd
+    RemoveInitrd
     WslValidateInstallation
     WslFinalizeInstallation
     InstallMsix