Factor running a debugger script into a helper function

python · pablogsal · Mar 22, 2025 · Mar 23, 2025 · Mar 23, 2025 · Mar 24, 2025
commit 38a4d51f679e5bed68de3396c91a26e50f9ef532
@@ -1192,6 +1192,71 @@ _PyEval_DisableGIL(PyThreadState *tstate)
 }
 #endif
 
+#ifdef Py_REMOTE_DEBUG
+// Note that this function is inline to avoid creating a PLT entry
+// that would be an easy target for a ROP gadget.
+static inline void run_remote_debugger_script(const char *path)
+{
+    if (0 != PySys_Audit("remote_debugger_script", "s", path)) {
+        PyErr_FormatUnraisable("Error when auditing remote debugger script %s", path);
+        return;
+    }
+
+    // Open the debugger script with the open code hook. Unfortunately this forces us to handle
+    // the resulting Python object, which is a file object and therefore we need to call
+    // Python methods on it instead of the simpler C equivalents.
+    PyObject* fileobj = PyFile_OpenCode(path);
+    if (!fileobj) {
+        PyErr_FormatUnraisable("Error when opening debugger script %s", path);
+        return;
+    }
+
+#ifdef MS_WINDOWS
+    PyObject* path_obj = PyUnicode_FromString(path);
+    if (!path_obj) {
+        PyErr_FormatUnraisable("Error when converting remote debugger script path %s to Unicode", path);
+        return;
+    }
+    wchar_t* wpath = PyUnicode_AsWideCharString(path_obj, NULL);
+    Py_DECREF(path_obj);
+    if (!wpath) {
+        PyErr_FormatUnraisable("Error when converting remote debugger script path %s to wide char", path);
+        return;
+    }
+    FILE* f = _wfopen(wpath, L"r");
+#else
+    int fd = PyObject_AsFileDescriptor(fileobj);
+    if (fd == -1) {
+        PyErr_FormatUnraisable("Error when getting file descriptor for debugger script %s", path);
+        return;
+    }
+    FILE* f = fdopen(fd, "r");
+#endif
+
+    if (!f) {
+        PyErr_SetFromErrno(PyExc_OSError);
+    } else {
+        PyRun_AnyFile(f, path);
+    }
+
+#ifdef MS_WINDOWS
+    PyMem_Free(wpath);
+    fclose(f);
+#endif
+
+    if (PyErr_Occurred()) {
+        PyErr_FormatUnraisable("Error executing debugger script %s", path);
+    }
+
+    PyObject* res = PyObject_CallMethod(fileobj, "close", "");
+    if (!res) {
+        PyErr_FormatUnraisable("Error when closing debugger script %s", path);
+    } else {
+        Py_DECREF(res);
+    }
+    Py_DECREF(fileobj);
+}
+#endif
 
 /* Do periodic things, like check for signals and async I/0.
 * We need to do reasonably frequently, but not too frequently.
@@ -1327,58 +1392,7 @@ _Py_HandlePending(PyThreadState *tstate)
             tstate->remote_debugger_support.debugger_pending_call = 0;
             const char *path = tstate->remote_debugger_support.debugger_script_path;
             if (*path) {
-                if (0 != PySys_Audit("remote_debugger_script", "s", path)) {
-                    PyErr_FormatUnraisable("Error when auditing remote debugger script %s", path);
-                } else {
-                    // Open the debugger script with the open code hook. Unfortunately this forces us to handle
-                    // the resulting Python object, which is a file object and therefore we need to call
-                    // Python methods on it instead of the simpler C equivalents.
-                    PyObject* fileobj = PyFile_OpenCode(path);
-                    if (!fileobj) {
-                        PyErr_FormatUnraisable("Error when opening debugger script %s", path);
-                        return 0;
-                    }
-#ifdef MS_WINDOWS
-                    PyObject* path_obj = PyUnicode_FromString(path);
-                    if (!path_obj) {
-                        PyErr_FormatUnraisable("Error when converting remote debugger script path %s to Unicode", path);
-                        return 0;
-                    } 
-                    wchar_t* wpath = PyUnicode_AsWideCharString(path_obj, NULL);
-                    Py_DECREF(path_obj);
-                    if (!wpath) {
-                        PyErr_FormatUnraisable("Error when converting remote debugger script path %s to wide char", path);
-                        return 0;
-                    }
-                    FILE* f = _wfopen(wpath, L"r");
-#else
-                    int fd = PyObject_AsFileDescriptor(fileobj);
-                    if (fd == -1) {
-                        PyErr_FormatUnraisable("Error when getting file descriptor for debugger script %s", path);
-                        return 0;
-                    }
-                    FILE* f = fdopen(fd, "r");
-#endif
-                    if (!f) {
-                        PyErr_SetFromErrno(PyExc_OSError);
-                    } else {
-                        PyRun_AnyFile(f, path);
-                    }
-#ifdef MS_WINDOWS
-                    PyMem_Free(wpath);
-                    fclose(f);
-#endif
-                    if (PyErr_Occurred()) {
-                        PyErr_FormatUnraisable("Error executing debugger script %s", path);
-                    }
-                    PyObject* res = PyObject_CallMethod(fileobj, "close", "");
-                    if (!res) {
-                        PyErr_FormatUnraisable("Error when closing debugger script %s", path);
-                    } else {
-                        Py_DECREF(res);
-                    }
-                    Py_DECREF(fileobj);
-                }
+                run_remote_debugger_script(path);
             }
         }
     }