1 #include "PythonReadline.h"
2 
3 #ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE
4 
5 #include <cstdio>
6 
7 #include <editline/readline.h>
8 
9 // Simple implementation of the Python readline module using libedit.
10 // In the event that libedit is excluded from the build, this turns
11 // back into a null implementation that blocks the module from pulling
12 // in the GNU readline shared lib, which causes linkage confusion when
13 // both readline and libedit's readline compatibility symbols collide.
14 //
15 // Currently it only installs a PyOS_ReadlineFunctionPointer, without
16 // implementing any of the readline module methods. This is meant to
17 // work around LLVM pr18841 to avoid seg faults in the stock Python
18 // readline.so linked against GNU readline.
19 //
20 // Bug on the cpython side: https://bugs.python.org/issue38634
21 
22 PyDoc_STRVAR(moduleDocumentation,
23              "Simple readline module implementation based on libedit.");
24 
25 #if PY_MAJOR_VERSION >= 3
26 static struct PyModuleDef readline_module = {
27     PyModuleDef_HEAD_INIT, // m_base
28     "lldb_editline",       // m_name
29     moduleDocumentation,   // m_doc
30     -1,                    // m_size
31     nullptr,               // m_methods
32     nullptr,               // m_reload
33     nullptr,               // m_traverse
34     nullptr,               // m_clear
35     nullptr,               // m_free
36 };
37 #else
38 static struct PyMethodDef moduleMethods[] = {{nullptr, nullptr, 0, nullptr}};
39 #endif
40 
41 static char *
42 #if PY_MAJOR_VERSION >= 3
43 simple_readline(FILE *stdin, FILE *stdout, const char *prompt)
44 #else
45 simple_readline(FILE *stdin, FILE *stdout, char *prompt)
46 #endif
47 {
48   rl_instream = stdin;
49   rl_outstream = stdout;
50   char *line = readline(prompt);
51   if (!line) {
52 #if PY_MAJOR_VERSION >= 3
53     char *ret = (char *)PyMem_RawMalloc(1);
54 #else
55     char *ret = (char *)PyMem_Malloc(1);
56 #endif
57     if (ret != NULL)
58       *ret = '\0';
59     return ret;
60   }
61   if (*line)
62     add_history(line);
63   int n = strlen(line);
64 #if PY_MAJOR_VERSION >= 3
65   char *ret = (char *)PyMem_RawMalloc(n + 2);
66 #else
67   char *ret = (char *)PyMem_Malloc(n + 2);
68 #endif
69   if (ret) {
70     memcpy(ret, line, n);
71     free(line);
72     ret[n] = '\n';
73     ret[n + 1] = '\0';
74   }
75   return ret;
76 }
77 
78 PyMODINIT_FUNC initlldb_readline(void) {
79   PyOS_ReadlineFunctionPointer = simple_readline;
80 
81 #if PY_MAJOR_VERSION >= 3
82   return PyModule_Create(&readline_module);
83 #else
84   Py_InitModule4("readline", moduleMethods, moduleDocumentation,
85                  static_cast<PyObject *>(NULL), PYTHON_API_VERSION);
86 #endif
87 }
88 #endif
89