tiennm99
f91a88f7b8
Build and publish a GitHub Release on each pushed v* tag (also runs on workflow_dispatch with a required tag input). The job runs on windows-latest, tests + clippies + release-builds the workspace via the pinned nightly toolchain, then zips time_mocker_ui.exe + time_mocker_hook.dll + LICENSE + README into time-mocker-<tag>-windows-x64.zip with a sha256 sidecar.
TimeMocker
A Windows tool that injects fake time into running processes by hooking Win32 time APIs. Written in Rust.
Status: Active development. This is the canonical implementation. Language-specific ports are available in C# (EasyHook) and C++ (MS Detours).
Architecture
time-mocker-rs/
├── crates/
│ ├── time-mocker-core/ — shared types (MockTimeInfo) + named MMF helper + tick conversions
│ ├── time-mocker-hook/ — cdylib injected into target processes; hooks 5 time APIs via retour
│ └── time-mocker-ui/ — egui controller binary; injects via dll-syringe, writes delta per PID
Hooked APIs
| API | DLL |
|---|---|
GetSystemTime |
kernel32 |
GetLocalTime |
kernel32 |
GetSystemTimeAsFileTime |
kernel32 |
GetSystemTimePreciseAsFileTime |
kernel32 |
NtQuerySystemTime |
ntdll |
IPC Design
Named Memory-Mapped File per injected process:
Name: TimeMocker_<PID>
Size: 8 bytes
[0..7] DeltaTicks (i64 — 100-ns units, added to the real FILETIME)
The hook reads the delta on every time API call and returns real_filetime + delta. The controller writes the delta whenever the user picks a new fake time.
Tick epoch difference vs the C# version: The C# version stores a delta against
DateTime.UtcNow.Ticks(epoch 0001-01-01 UTC). The Rust version stores a delta in raw FILETIME units (epoch 1601-01-01 UTC). The two IPC contracts are not interoperable — the Rust UI and Rust hook DLL only talk to each other.
Build
# Nightly Rust (required by retour for inline x64 detours)
# A `rust-toolchain.toml` at the repo root pins the channel automatically.
cargo build --release
# Outputs:
# target/release/time_mocker_ui.exe
# target/release/time_mocker_hook.dll (must be next to the UI exe)
Requirements
- Windows 10/11 x64
- Rust nightly (pinned via
rust-toolchain.toml) - Must run as Administrator (UAC manifest embedded)
License
Apache-2.0 — see LICENSE.
Related
- time-mocker-csharp — C# / EasyHook implementation
- time-mocker-cpp — C++ / MS Detours implementation