# LinuxCNC WASM shims source map

This map records the source basis for the C++ sources in the
CMake `linuxcnc_wasm_safe_probe_shims` set. It is a build/source-link guard
only; it must not add CNC behavior and must not expand the temporary smoke parser.

## Generated Coverage

| Output | Count | Source coverage role |
| --- | ---: | --- |
| CMake `linuxcnc_wasm_safe_probe_shims` sources | 11 | Browser-safe LinuxCNC adaptation shims linked into WASM source probes. |

## Shim Map

| Shim | LinuxCNC source basis | Boundary |
| --- | --- | --- |
| `core/wasm_shims/dlfcn.cc` | `src/emc/rs274ngc/interp_base.cc` | Satisfies native `dlopen` symbols for browser-safe probes while keeping dynamic loading unavailable. |
| `core/wasm_shims/emc_status_shim.cc` | `src/emc/sai/dummyemcstat.cc` | Provides the source-backed `emcStatus` singleton shape without task/NML startup. |
| `core/wasm_shims/gettext_shim.cc` | `src/emc/rs274ngc/interp_internal.hh` | Preserves LinuxCNC `_()` diagnostic call sites by satisfying `gettext()` while leaving browser gettext catalogs unavailable. |
| `core/wasm_shims/linuxcnc_runtime_shim.cc` | `src/emc/rs274ngc/gcodemodule.cc`, `src/emc/task/emctaskmain.cc`, `src/emc/task/taskclass.cc`, `src/emc/rs274ngc/interp_namedparams.cc`, `include/hal.h`, `src/hal/hal_lib.c`, `src/emc/rs274ngc/rs274ngc_pre.cc` | Keeps preview/task, builtin Python module, unavailable HAL lookup, and `wordexp()` edges compile-safe. |
| `core/wasm_shims/nml_status_shim.cc` | `src/libnml/nml/nmlmsg.cc`, `src/libnml/nml/stat_msg.cc` | Provides LinuxCNC NML status constructors, clear behavior, and `RCS_STAT_MSG` default status fields needed by source-linked EMC status objects. |
| `core/wasm_shims/python_c_api_shim.cc` | `src/emc/rs274ngc/interp_python.cc`, `src/emc/rs274ngc/interp_namedparams.cc`, `src/emc/rs274ngc/gcodemodule.cc`, `src/emc/pythonplugin/python_plugin.cc` | Satisfies Python C API symbols while Python/Boost.Python remap paths remain tracked blockers. |
| `core/wasm_shims/rcs_print_shim.cc` | `src/libnml/rcs/rcs_print.cc`, `src/libnml/rcs/rcs_print.hh` | Provides the LinuxCNC `rcs_print_error` split entry points used by NML validation without native print routing. |
| `core/wasm_shims/rtapi_compat.cc` | `src/rtapi/uspace_common.h`, `src/rtapi/rtapi.h` | Provides LinuxCNC userspace `rtapi_snprintf()` formatting by following the `rtapi.h` declaration and `uspace_common.h` `vsnprintf()` implementation path. |
| `core/wasm_shims/tooldata/tooldata_mmap_backend.cc` | `src/emc/tooldata/tooldata_mmap.cc` | Replaces native mmap storage with an in-memory WASM-safe backend for probes. |
| `core/wasm_shims/tooldata/tooldata_runtime_stubs.cc` | `src/emc/tooldata/tooldata_nml.cc`, `src/emc/tooldata/tooldata_db.cc` | Satisfies NML and external tool database entry points without native services, preserving inactive-DB return values. |
| `core/wasm_shims/pythonplugin/python_plugin.cc` | `src/emc/pythonplugin/python_plugin.cc`, `src/emc/pythonplugin/python_plugin.hh` | Keeps LinuxCNC PythonPlugin API and negative-status short-circuit behavior available while Python execution is disabled for browser-safe probes. |

## Runtime Shim Boundaries

- `core/wasm_shims/linuxcnc_runtime_shim.cc` must keep `_task=0` for preview,
  matching `src/emc/rs274ngc/gcodemodule.cc`; it must not switch browser-safe probes into task mode.
- The HAL lookup shim covers `hal_get_pin_value_by_name()`,
  `hal_get_signal_value_by_name()`, and `hal_get_param_value_by_name()` from
  `src/emc/rs274ngc/interp_namedparams.cc`, `include/hal.h`, and
  `src/hal/hal_lib.c`; it must leave HAL values unavailable by returning `-1`,
  `HAL_TYPE_UNINITIALIZED`, and null data pointers.
- `wordexp()` support is limited to the browser-safe path expansion needed by
  `src/emc/rs274ngc/rs274ngc_pre.cc`; it must not become a shell expansion feature.

## Python Shim Boundaries

- `core/wasm_shims/python_c_api_shim.cc` satisfies Python C API symbols used by
  LinuxCNC RS274/remap sources; it must not become Python execution.
- `core/wasm_shims/pythonplugin/python_plugin.cc` must preserve LinuxCNC
  `PythonPlugin` status edges for `PLUGIN_NO_SECTION`, `PLUGIN_BAD_INIFILE`,
  `PLUGIN_PYTHON_NOT_INITIALIZED`, `PLUGIN_NO_CALLABLE`, and
  `PLUGIN_EXCEPTION` while keeping Python execution disabled.
- The PythonPlugin shim must not execute `bp::exec`, `bp::exec_file`, or
  `PyObject_Call`; those remain browser blockers until implemented as a
  source-backed browser-safe LinuxCNC adaptation.

## Boundaries

- The CMake `linuxcnc_wasm_safe_probe_shims` set and `list-linuxcnc-wasm-safe-shims.sh` must stay synchronized.
- Each shim source must keep a nearby `LinuxCNC source basis:` comment naming the LinuxCNC source it adapts.
- Every LinuxCNC source named above must remain tracked in the RS274/WASM manifest as `core`, `header`, or `metadata`.
- These shims are browser-safe LinuxCNC adaptations for source-link probes; they are not new interpreter behavior.
- `test-native.sh`, `test-linuxcnc-source-link.sh`, and `build-wasm.sh` must
  run `./check-linuxcnc-wasm-shims-source-map.sh` before consuming shim-backed
  source-linked LinuxCNC objects or browser artifacts.
- The WASM shims source-map guard validates LinuxCNC source/shim ownership and
  manifest drift only; it does not interpret G-code.

## Checks

Run:

```bash
./check-linuxcnc-wasm-shims-source-map.sh
./test-linuxcnc-wasm-cmake-safe-probe.sh
./test-native.sh
./test-linuxcnc-source-link.sh
./build-wasm.sh
```

`check-linuxcnc-wasm-shims-source-map.sh` keeps this document, the CMake shim
set, `list-linuxcnc-wasm-safe-shims.sh`, LinuxCNC source anchors, and the
RS274/WASM manifest synchronized.