Extend the clipboard target boundary with ordered prefix delivery.
Pass up to four queued LGMP stream records to the Helper ring in one
operation, apply state only to the accepted prefix, and retain the
remaining suffix for exact retries.
The channel holds its write lock across the prefix and emits one pipe
doorbell per stream window instead of one per record.
Keep inbound stream payloads in the bounded stream-target window while
the Helper channel is busy and publish directly from those buffers.
Retain the pending target only for LGMP queue controls. Their credits
remain outstanding across retries.
This removes one full payload copy per client-to-Helper record without
changing delivery order, backpressure, or reset behavior.
Add a reusable copy path for moving data from write-combined mappings
into normal cacheable memory. Dispatch to MOVNTDQA-based SSE4.1 or AVX2
loads when the processor and OS support them, with a fenced fallback.
Use the optimized path when staging inbound clipboard stream records from
the IVSHMEM mapping.
Drive adaptive clipboard stream polling with a high-resolution waitable
timer instead of rounding microsecond delays into coarse wait-function
timeouts.
Preserve the explicit stop and local wake events while avoiding a clock-tick
stall at each file-transfer window.
Use the documented Win32 wait constants throughout the pipe, clipboard,
and input workers instead of local numeric aliases.
Select the WDK NT-status definitions before including Windows headers.
Include wudfwdm.h privately in the affected translation units so UMDF 2
provides NTSTATUS without exposing WDF headers through LGCommon's public
interface to the desktop Helper.
Carry DATA and FILE_DATA only through the duplex SPSC streams. Keep LGMP
queues for control and status. Remove grants, commits, ACKs, and
queue-payload transport negotiation.
Poll adaptively while ownership or release is active. Preserve FIFO
release and graceful draining. Quarantine payloads crossed by a newer
OFFER or CLEAR, and retire data-plane state on detach.
Carry every input activation and report through its client-bound SPSC
stream. Keep the LGMP queue only for status publication and subscriber
discovery, removing transport selection and the queue-report fallback.
Retain graceful endpoint draining when a subscriber disappears and use
bounded adaptive polling while streams are active. The IDD polling setup
remains compatible with the project’s current C++ language mode.
Publish ordered four-record prefixes through the Helper mapping and ring
once per accepted burst. Wake blocked producers when the peer returns
credits while retaining the bounded polling fallback.
Move received payload ownership into manager work items and place remote
file-read data directly into the waiting caller’s bounded output buffer.
This removes avoidable 256 KiB copies without changing record ordering,
timeouts, cancellation, or reset semantics.
Create and advertise one reliable input stream for each possible LGMP
client, then bind endpoints to active input subscribers.
Drain endpoints fairly while prioritizing the current owner's lane so
its RELEASE remains the ordering barrier. Reject transport changes
within an activation generation.
Gracefully retire missing or stalled subscribers without reusing an
active reservation. Keep excess clients on the queue and release HID
ownership from the input worker when its stream retires.
Create one reliable four-slot lane in each direction and advertise the
stream data plane for clipboard protocol v4.
Bind both lanes to the accepted owner generation, stage incoming data
within a fixed window, and apply backpressure when Helper delivery is
full.
Drain reliable records before releasing an owner. Force stale or
unresponsive bindings after a bounded deadline while preserving the
existing cancellation and clipboard-clear cleanup.
Expose LGMP stream creation through the existing IDD host wrapper so
subsystem transports do not reach through its ownership boundary.
Keep stream lifetime and binding under each transport while the host
continues to own the underlying shared-memory allocator.
Explorer file copies were invisible to the Helper because the service
launched its child with a duplicate of the LocalSystem token and changed
only TokenSessionId. The child therefore remained a System-integrity
process. Windows filtered Explorer's file clipboard formats across that
integrity boundary. Basic text and bitmap formats continued to work.
Keep only the SCM service privileged. Obtain the active session user's
primary token with WTSQueryUserToken. For elevated accounts, prefer the
linked limited token. Validate its session and security properties.
Build the user environment and launch the interactive Helper on
WinSta0\Default. Gate Helper activation until the service has rechecked
the active session and registered the clipboard authority.
Use random lifetime, stop, and activation objects owned by the service.
Give the target logon SID synchronization access only. Recheck the
active console session and service state before activation. Make the
lifetime mutex terminate the Helper if the service exits unexpectedly.
Restart it when the active session, IDD host, or authority changes.
Replace the old process-handle mapping transfer with a device-bound
authority protocol on the LGIdd device interface. The service verifies
the exact driver host instance, duplicates only section map rights into
that process, and registers the session, mapping identifier, and handle.
Bind authority lifetime to its WDF file object, revoke it synchronously
on cleanup, and poll the driver host identity while the child is active.
Restrict the device stack to SYSTEM and isolate LGIdd in a unique UMDF
device group. Restrict the shared section to SYSTEM and the target logon
SID. Apply a medium mandatory label that prevents low-integrity readers
and writers. Map it with read/write rights instead of all access.
Give each clipboard mapping a second random authority identifier. Store
it only inside the logon-SID-protected mapping and send it in the
mandatory HELLO. LGIdd matches it against the service-injected mapping.
This authenticates the user Helper without the unsupported UMDF call to
GetNamedPipeClientSessionId. Have the Helper verify that its pipe server
is in session zero.
Extend the pipe endpoint with bounded authentication reads, cancellable
overlapped I/O, periodic authorization checks, and explicit disconnects.
Serialize authority changes with clipboard attach and detach. Prevent
stale cleanup from tearing down a replacement mapping. Disconnect the
user pipe immediately when its owning authority is revoked.
Run clipboard, OLE, display, configuration, and file access in the
user's interactive process. Retain its process token for worker-thread
file operations instead of querying and impersonating the desktop user
from a System process. Store Helper logs in LocalAppData and grant only
the registry rights needed by interactive configuration and UMDF.
Keep immediate, stage-specific Win32 and HRESULT diagnostics throughout
clipboard capture. Probe CF_HDROP while holding the Win32 clipboard and
enumerate the OLE object's advertised file formats. Validate returned
storage and fall back to Shell item paths when direct retrieval fails.
Validate clipboard sequence changes and defer retries during contention
without publishing incomplete clipboard state.
Complete the 1 MiB transfer work with full-sized Windows copy buffers.
Use full-sized FUSE reads and retain the named 64 KiB X11 chunk limit.
Validate the user-writable mapping with CClipboardRing before attaching.
The pipe, mapping, and authority protocols change together. LGIdd.dll,
the INF, and LGIddHelper.exe must be rebuilt and installed as one
matching set.
Add a protocol-independent recovery channel outside LGMP so clients can
request a usable guest display even when transport versions differ.
Synchronize recovery state with the helper across driver restarts and
restore the configured topology without persisting temporary changes.
Define a fixed, protocol-independent recovery ABI in the final 64 KiB
of IVSHMEM.
Provide crash-safe multi-client requests and coherent producer status.
Exclude the region from LGMP allocation and frame capacity so future
protocol mismatches retain a stable control path.
