diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/CMakeLists.txt b/lldb/source/Plugins/ScriptInterpreter/Python/CMakeLists.txt --- a/lldb/source/Plugins/ScriptInterpreter/Python/CMakeLists.txt +++ b/lldb/source/Plugins/ScriptInterpreter/Python/CMakeLists.txt @@ -5,6 +5,7 @@ add_lldb_library(lldbPluginScriptInterpreterPython PLUGIN PythonDataObjects.cpp + PythonReadline.cpp ScriptInterpreterPython.cpp LINK_LIBS diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.h b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.h new file mode 100644 --- /dev/null +++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.h @@ -0,0 +1,26 @@ +//===-- PythonReadline.h ----------------------------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONREADLINE_H +#define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONREADLINE_H + +#if !defined(LLDB_DISABLE_LIBEDIT) && !defined(__APPLE__) +// NOTE: Since Python may define some pre-processor definitions which affect the +// standard headers on some systems, you must include Python.h before any +// standard headers are included. +#include "Python.h" + +// no need to hack into Python's readline module if libedit isn't used. +// +#define LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE 1 + +extern "C" PyMODINIT_FUNC initlldb_readline(void); + +#endif + +#endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONREADLINE_H diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp new file mode 100644 --- /dev/null +++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp @@ -0,0 +1,80 @@ +#include "PythonReadline.h" + +#ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE + +#include + +#include + +// Simple implementation of the Python readline module using libedit. +// In the event that libedit is excluded from the build, this turns +// back into a null implementation that blocks the module from pulling +// in the GNU readline shared lib, which causes linkage confusion when +// both readline and libedit's readline compatibility symbols collide. +// +// Currently it only installs a PyOS_ReadlineFunctionPointer, without +// implementing any of the readline module methods. This is meant to +// work around LLVM pr18841 to avoid seg faults in the stock Python +// readline.so linked against GNU readline. +// +// Bug on the cpython side: https://bugs.python.org/issue38634 + +PyDoc_STRVAR(moduleDocumentation, + "Simple readline module implementation based on libedit."); + +#if PY_MAJOR_VERSION >= 3 +static struct PyModuleDef readline_module = { + PyModuleDef_HEAD_INIT, // m_base + "lldb_editline", // m_name + moduleDocumentation, // m_doc + -1, // m_size + nullptr, // m_methods + nullptr, // m_reload + nullptr, // m_traverse + nullptr, // m_clear + nullptr, // m_free +}; +#else +static struct PyMethodDef moduleMethods[] = {{nullptr, nullptr, 0, nullptr}}; +#endif + +static char * +#if PY_MAJOR_VERSION >= 3 +simple_readline(FILE *stdin, FILE *stdout, const char *prompt) +#else +simple_readline(FILE *stdin, FILE *stdout, char *prompt) +#endif +{ + rl_instream = stdin; + rl_outstream = stdout; + char *line = readline(prompt); + if (!line) { + char *ret = (char *)PyMem_RawMalloc(1); + if (ret != NULL) + *ret = '\0'; + return ret; + } + if (*line) + add_history(line); + int n = strlen(line); + char *ret = (char *)PyMem_RawMalloc(n + 2); + if (ret) { + strncpy(ret, line, n); + free(line); + ret[n] = '\n'; + ret[n + 1] = '\0'; + } + return ret; +} + +PyMODINIT_FUNC initlldb_readline(void) { + PyOS_ReadlineFunctionPointer = simple_readline; + +#if PY_MAJOR_VERSION >= 3 + return PyModule_Create(&readline_module); +#else + Py_InitModule4("lldb_readline", moduleMethods, moduleDocumentation, + static_cast(NULL), PYTHON_API_VERSION); +#endif +} +#endif diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp --- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp +++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp @@ -16,6 +16,7 @@ #include "lldb-python.h" #include "PythonDataObjects.h" +#include "PythonReadline.h" #include "ScriptInterpreterPythonImpl.h" #include "lldb/API/SBFrame.h" @@ -217,6 +218,22 @@ InitializePythonHome(); +#ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE + // Python's readline is incompatible with libedit being linked into lldb. + // Provide a patched version local to the embedded interpreter. + bool ReadlinePatched = false; + for (auto *p = PyImport_Inittab; p->name != NULL; p++) { + if (strcmp(p->name, "readline") == 0) { + p->initfunc = initlldb_readline; + break; + } + } + if (!ReadlinePatched) { + PyImport_AppendInittab("readline", initlldb_readline); + ReadlinePatched = true; + } +#endif + // Register _lldb as a built-in module. PyImport_AppendInittab("_lldb", LLDBSwigPyInit);