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Merged
benhillis merged 1 commit into from
Feb 9, 2026
Merged

Minor follow-up initrd feedback items #14186

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7 changes: 4 additions & 3 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,6 @@ tmp
*.user
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@benhillis benhillis Feb 9, 2026

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unrelated but I keep getting annoyed that the test-storage directory isn't in the gitignore in the main branch.

*.csproj
*.vcxproj
*.targets
*.filters
*.pdb
*.lib
Expand Down Expand Up @@ -42,7 +41,6 @@ linux/init
initrd/init
bin/
*.nupkg
build/
generated/
*.nuspec
test/linux/unit_tests/wsl_unit_tests
Expand All @@ -65,4 +63,7 @@ package/x64
/appx-logs.txt
tools/clang-format.exe
/linux-crashes
doc/site/
doc/site/
directory.build.targets
test-storage/
*.vhdx
3 changes: 1 addition & 2 deletions msipackage/package.wix.in
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Expand Up @@ -540,8 +540,7 @@
<!-- 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.
Only run when the tools component is being installed ($tools=3), not during same-version reinstalls -->
<!-- Generate initrd.img from the init binary whenever the tools component is being installed -->
<Custom Action="CreateInitrd" After="RegisterLspCategories" Condition='$tools=3' />

<!-- This needs to run before the registry is cleared because this action needs to read the install path.
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8 changes: 5 additions & 3 deletions src/windows/common/filesystem.cpp
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Expand Up @@ -1143,6 +1143,7 @@ void wsl::windows::common::filesystem::CreateCpioInitrd(_In_ const std::filesyst
constexpr size_t headerSize = 110;
const auto nameLen = strlen(name) + 1;
const auto headerPadding = (4 - ((headerSize + nameLen) % 4)) % 4;
const bool isTrailer = strcmp(name, "TRAILER!!!") == 0;

// Get current time for mtime. CPIO newc format only supports 32-bit fields.
const auto mtime = static_cast<DWORD>(time(nullptr));
Expand All @@ -1165,10 +1166,10 @@ void wsl::windows::common::filesystem::CreateCpioInitrd(_In_ const std::filesyst
"%08X" // namesize
"%08X", // check
0,
(fileSize > 0) ? 0100755 : 0,
isTrailer ? 0 : 0100755,
0,
0,
(fileSize > 0) ? 1 : 0,
isTrailer ? 0 : 1,
Comment on lines 1168 to +1172
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Copilot AI Feb 9, 2026

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This changes the CPIO header fields so that empty files (fileSize==0) still get a regular-file mode/nlink, and only the trailer gets zeros. The existing CreateCpioInitrd test parses filesize/namesize but doesn’t assert mode/nlink, so it wouldn’t catch regressions in this logic. Consider extending the test to parse and validate mode/nlink at least for sourceSize=0 (and ideally also validate the trailer entry).

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mtime,
fileSize,
0,
Expand Down Expand Up @@ -1214,7 +1215,8 @@ void wsl::windows::common::filesystem::CreateCpioInitrd(_In_ const std::filesyst
LARGE_INTEGER currentPos{};
THROW_IF_WIN32_BOOL_FALSE(SetFilePointerEx(destFile.get(), {}, &currentPos, FILE_CURRENT));

const auto archivePadding = (archiveBlockSize - (currentPos.LowPart % archiveBlockSize)) % archiveBlockSize;
const auto currentSize = static_cast<ULONGLONG>(currentPos.QuadPart);
const auto archivePadding = static_cast<DWORD>((archiveBlockSize - (currentSize % archiveBlockSize)) % archiveBlockSize);
if (archivePadding > 0)
{
char paddingBuffer[archiveBlockSize] = {0};
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6 changes: 3 additions & 3 deletions test/windows/SimpleTests.cpp
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Expand Up @@ -325,10 +325,10 @@ class SimpleTests
THROW_IF_WIN32_BOOL_FALSE(GetFileSizeEx(cpioHandle.get(), &cpioSize));
VERIFY_ARE_EQUAL(cpioSize.QuadPart % 512, 0LL); // Archive padded to 512-byte boundary

char header[110] = {};
char header[111] = {};
DWORD bytesRead;
THROW_IF_WIN32_BOOL_FALSE(ReadFile(cpioHandle.get(), header, sizeof(header), &bytesRead, nullptr));
VERIFY_ARE_EQUAL(bytesRead, static_cast<DWORD>(sizeof(header)));
THROW_IF_WIN32_BOOL_FALSE(ReadFile(cpioHandle.get(), header, 110, &bytesRead, nullptr));
VERIFY_ARE_EQUAL(bytesRead, 110u);
Comment on lines +330 to +331
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Copilot AI Feb 9, 2026

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The header size is hard-coded as 110 in both the ReadFile length and the VERIFY_ARE_EQUAL check. Since the buffer size was just changed to 111 to include a null terminator, consider using a single named constant (or sizeof(header) - 1) to keep the read length/check consistent and avoid future off-by-one drift.

Suggested change
THROW_IF_WIN32_BOOL_FALSE(ReadFile(cpioHandle.get(), header, 110, &bytesRead, nullptr));
VERIFY_ARE_EQUAL(bytesRead, 110u);
const DWORD headerBytesToRead = static_cast<DWORD>(sizeof(header) - 1);
THROW_IF_WIN32_BOOL_FALSE(ReadFile(cpioHandle.get(), header, headerBytesToRead, &bytesRead, nullptr));
VERIFY_ARE_EQUAL(bytesRead, headerBytesToRead);

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// Parse CPIO newc header: magic(6) ino mode uid gid nlink mtime filesize devmajor devminor rdevmajor rdevminor namesize check
DWORD fileSize, nameSize;
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