尽快推进：收紧dlfcn shim源码锚点

check-linuxcnc-wasm-shims-source-map.sh

@@ -178,7 +178,31 @@ for shim_path, linuxcnc_sources in expected_shims.items():
 
 runtime_shim = Path("core/wasm_shims/linuxcnc_runtime_shim.cc").read_text(encoding="utf-8")
 runtime_probe = Path("core/wasm_shims/cnc_sim_wasm_runtime_probe_main.cc").read_text(encoding="utf-8")
+dlfcn_shim = Path("core/wasm_shims/dlfcn.cc").read_text(encoding="utf-8")
+dlfcn_header = Path("core/wasm_shims/dlfcn.h").read_text(encoding="utf-8")
 gettext_shim = Path("core/wasm_shims/gettext_shim.cc").read_text(encoding="utf-8")
+for needle in [
+    "#define RTLD_GLOBAL 0x00100",
+    "#define RTLD_NOW 0x00002",
+    "void *dlopen(const char *filename, int flags);",
+    "void *dlsym(void *handle, const char *symbol);",
+    "char *dlerror(void);",
+    "int dlclose(void *handle);",
+]:
+    if needle not in dlfcn_header:
+        raise SystemExit(f"dlfcn shim header missing LinuxCNC loader boundary: {needle}")
+for needle in [
+    "dynamic loading is unavailable in wasm-safe probe",
+    "void *dlopen(const char *, int)",
+    "return nullptr;",
+    "void *dlsym(void *, const char *)",
+    "char *dlerror(void)",
+    "return last_error;",
+    "int dlclose(void *)",
+    "return 0;",
+]:
+    if needle not in dlfcn_shim:
+        raise SystemExit(f"dlfcn shim missing unavailable-loader boundary: {needle}")
 for needle in [
     "extern \"C\" char *gettext(const char *msgid)",
     "return const_cast<char *>(msgid ? msgid : \"\");",
@@ -280,6 +304,8 @@ for phrase in [
     "CMake `linuxcnc_wasm_safe_probe_shims` set",
     "RS274/WASM manifest",
     "browser-safe LinuxCNC adaptations",
+    "LinuxCNC `interp_base.cc` dynamic loader calls",
+    "unavailable-loader returns",
     "LinuxCNC `_()` diagnostic call sites",
     "browser gettext catalogs unavailable",
     "LinuxCNC NML status constructors",

docs/linuxcnc-wasm-shims-source-map.md

@@ -14,7 +14,7 @@ only; it must not add CNC behavior and must not expand the temporary smoke parse
 
 | 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/dlfcn.cc` | `src/emc/rs274ngc/interp_base.cc` | Satisfies LinuxCNC `interp_base.cc` dynamic loader calls and RTLD flags 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. |
@@ -28,6 +28,11 @@ only; it must not add CNC behavior and must not expand the temporary smoke parse
 
 ## Runtime Shim Boundaries
 
+- `core/wasm_shims/dlfcn.cc` and `core/wasm_shims/dlfcn.h` cover the
+  LinuxCNC `interp_base.cc` dynamic loader calls to `dlopen()`, `dlsym()`,
+  `dlerror()`, `RTLD_GLOBAL`, and `RTLD_NOW`; their unavailable-loader returns
+  must keep handles and symbols null, keep `dlerror()` diagnostic text stable,
+  and leave `dlclose()` side-effect free.
 - `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()`,