Harden LinuxCNC wasm and native probe workflows

core/wasm_shims/pythonplugin/python_plugin.cc

@@ -0,0 +1,50 @@
+#include "pythonplugin/python_plugin.hh"
+
+__attribute__((weak)) std::string handle_pyerror() {
+    return "python disabled in wasm-safe probe";
+}
+
+PythonPlugin *python_plugin = nullptr;
+
+PythonPlugin *PythonPlugin::instantiate(struct _inittab *) {
+    static PythonPlugin plugin;
+    python_plugin = &plugin;
+    python_plugin->status = PLUGIN_OK;
+    return python_plugin;
+}
+
+int PythonPlugin::configure(const char *, const char *) {
+    status = PLUGIN_OK;
+    return status;
+}
+
+bool PythonPlugin::is_callable(const char *, const char *) {
+    return false;
+}
+
+int PythonPlugin::call(const char *,
+                       const char *,
+                       boost::python::object,
+                       boost::python::object,
+                       boost::python::object &retval) {
+    retval = boost::python::object();
+    status = PLUGIN_NO_CALLABLE;
+    return status;
+}
+
+int PythonPlugin::run_string(const char *, boost::python::object &retval, bool) {
+    retval = boost::python::object();
+    status = PLUGIN_OK;
+    return status;
+}
+
+int PythonPlugin::call_method(boost::python::object, boost::python::object &retval) {
+    retval = boost::python::object();
+    status = PLUGIN_OK;
+    return status;
+}
+
+int PythonPlugin::initialize() {
+    status = PLUGIN_OK;
+    return status;
+}

core/wasm_shims/pythonplugin/python_plugin.hh

@@ -0,0 +1,60 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <sys/types.h>
+
+#include "boost/python/object.hpp"
+
+extern std::string handle_pyerror();
+
+enum pp_status {
+    PLUGIN_NO_SECTION = -1,
+    PLUGIN_NO_INIFILE = -2,
+    PLUGIN_BAD_INIFILE = -3,
+    PLUGIN_NO_TOPLEVEL = -4,
+    PLUGIN_BAD_PATH = -5,
+    PLUGIN_STAT_FAILED = -6,
+    PLUGIN_INITTAB_FAILED = -7,
+    PLUGIN_PYTHON_ALREADY_INITIALIZED = -8,
+    PLUGIN_EXCEPTION_DURING_PATH_PREPEND = -9,
+    PLUGIN_EXCEPTION_DURING_PATH_APPEND = -10,
+    PLUGIN_INIT_EXCEPTION = -11,
+    PLUGIN_PYTHON_NOT_INITIALIZED = -12,
+    PLUGIN_PATH_TOO_LONG = -13,
+    PLUGIN_OK = 0,
+    PLUGIN_NO_CALLABLE = 1,
+    PLUGIN_EXCEPTION = 2
+};
+
+class PythonPlugin {
+public:
+    static PythonPlugin *instantiate(struct _inittab *inittab = nullptr);
+    int configure(const char *iniFilename = nullptr, const char *section = nullptr);
+    bool is_callable(const char *module, const char *funcname);
+    int call(const char *module,
+             const char *callable,
+             boost::python::object tupleargs,
+             boost::python::object kwargs,
+             boost::python::object &retval);
+    int run_string(const char *cmd, boost::python::object &retval, bool as_file = false);
+    int call_method(boost::python::object method, boost::python::object &retval);
+
+    int plugin_status() { return status; }
+    bool usable() { return status >= PLUGIN_OK; }
+    int initialize();
+    const std::string &last_exception() { return exception_msg; }
+    const std::string &last_errmsg() { return error_msg; }
+    boost::python::object main_namespace;
+
+private:
+    PythonPlugin() = default;
+
+    int status = PLUGIN_OK;
+    std::string exception_msg;
+    std::string error_msg;
+    int log_level = 0;
+};
+
+extern PythonPlugin *python_plugin;
+

core/wasm_shims/pythonplugin/python_plugin_probe_main.cc

@@ -0,0 +1,23 @@
+#include "pythonplugin/python_plugin.hh"
+
+int main() {
+    auto *plugin = PythonPlugin::instantiate(nullptr);
+    if (!plugin) {
+        return 1;
+    }
+    if (!plugin->usable()) {
+        return 2;
+    }
+    boost::python::object retval;
+    if (plugin->run_string("noop", retval, false) != PLUGIN_OK) {
+        return 3;
+    }
+    if (plugin->is_callable(nullptr, "noop")) {
+        return 4;
+    }
+    if (handle_pyerror().empty()) {
+        return 5;
+    }
+    return 0;
+}
+