in_windows_exporter_metrics: Plug bitwise glitches on 32bit oses

[cosmo0920]

After long running investigations, we found that some of the bit width glitches on 32bit executable of Fluent Bit.
With this PR, we can retrieve prometheus compatible payloads from 32bit version of fluent-bit.exe.

Closes #10130.

I confirmed that it can retrieve from prometheus_exporter with curl(WebRequest-Invoke Cmdlet) on x86_64 Windows and 32bit/64bit exe pairs, and ARM64 Windows platforms.
32bit/64bit/arm64 executables of fluent-bit.exe are working as expected.

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Testing
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Documentation

• Documentation required for this feature

Backporting

• Backport to latest stable release.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

Summary by CodeRabbit

• Bug Fixes
  • Fixed a memory allocation bug in text conversion to prevent incorrect buffer sizing and potential corruption.
  • Improved Windows metrics initialization to use per-context resources, with stronger cleanup on failures to avoid leaks.
  • Added more robust error detection and logging for query execution and iteration, improving troubleshooting and reliability.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 997bff2b-71df-443c-b107-b2ad0b3d090d

📥 Commits

Reviewing files that changed from the base of the PR and between eab065c and 900c4cc.

📒 Files selected for processing (1)

• plugins/in_windows_exporter_metrics/we_wmi.c

🚧 Files skipped from review as they are similar to previous changes (1)

• plugins/in_windows_exporter_metrics/we_wmi.c

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📝 Walkthrough

Walkthrough

Adds a per-context IWbemContext to the Windows exporter metrics input plugin, sets architecture VARIANTs in that context, passes it to ConnectServer/ExecQuery, fixes wide-string allocation, checks IWbemClassObject::Next HRESULTs, and releases the context on cleanup or failure.

Changes

WMI Context Management

Layer / File(s)	Summary
WMI Context Type Definitions and Utilities plugins/in_windows_exporter_metrics/we.h, plugins/in_windows_exporter_metrics/we_util.c	struct flb_we gains IWbemContext *wmi_context; we_convert_str() allocates wide buffer using sizeof(wchar_t).
WMI Context Initialization with Architecture Constraints plugins/in_windows_exporter_metrics/we_wmi.c	wmi_coinitialize creates ctx->wmi_context, sets __ProviderArchitecture and __RequiredArchitecture VARIANTs, allocates namespace BSTR, passes context to ConnectServer, and releases context on failures.
WMI Query Execution with Context plugins/in_windows_exporter_metrics/we_wmi.c	wmi_execute_query allocates BSTRs for WQL language/query and calls ExecQuery with ctx->wmi_context, freeing BSTRs afterward.
Query Enumeration Result Handling and Error Checking plugins/in_windows_exporter_metrics/we_wmi.c	wmi_exec_query_fixed_val and wmi_exec_query check IWbemClassObject::Next HRESULTs, log on failure, and log debug when no items are returned.
WMI Context Lifecycle: Init and Cleanup plugins/in_windows_exporter_metrics/we_wmi.c	we_wmi_init initializes ctx->wmi_context to NULL; wmi_cleanup releases and NULLs ctx->wmi_context.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested labels

backport to v4.0.x, backport to v4.1.x

Suggested reviewers

• edsiper
• fujimotos
• koleini

Poem

🐰 A rabbit hops through WMI's domain,
With context now bound, no endless refrain,
Architecture flags set snug and tight,
Queries run steady into the night,
Cleanup clears footprints—hopping light! ✨

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Title check	❓ Inconclusive	The title is vague and uses technical jargon ('bitwise glitches') without clearly explaining what the PR fixes or changes.	Consider a more descriptive title like 'Fix WMI context initialization for 32-bit Windows builds' that clearly indicates the primary change.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	The PR addresses the core issue #10130 by fixing WMI initialization bugs affecting 32-bit builds through proper context management and buffer allocation.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the reported 32-bit Windows issues: WMI context initialization, buffer allocation correction, and proper error handling.

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✨ Finishing Touches

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🧪 Generate unit tests (beta)

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• Commit unit tests in branch cosmo0920-plug-bitwise-glitches-on-32bit-oses

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