LLDB mainline
PythonReadline.cpp
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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
22PyDoc_STRVAR(moduleDocumentation,
23 "Simple readline module implementation based on libedit.");
24
25static struct PyModuleDef readline_module = {
26 PyModuleDef_HEAD_INIT, // m_base
27 "lldb_editline", // m_name
28 moduleDocumentation, // m_doc
29 -1, // m_size
30 nullptr, // m_methods
31 nullptr, // m_reload
32 nullptr, // m_traverse
33 nullptr, // m_clear
34 nullptr, // m_free
35};
36
37static char *simple_readline(FILE *stdin, FILE *stdout, const char *prompt) {
38 rl_instream = stdin;
39 rl_outstream = stdout;
40 char *line = readline(prompt);
41 if (!line) {
42 char *ret = (char *)PyMem_RawMalloc(1);
43 if (ret != nullptr)
44 *ret = '\0';
45 return ret;
46 }
47 if (*line)
48 add_history(line);
49 int n = strlen(line);
50 char *ret = (char *)PyMem_RawMalloc(n + 2);
51 if (ret) {
52 memcpy(ret, line, n);
53 free(line);
54 ret[n] = '\n';
55 ret[n + 1] = '\0';
56 }
57 return ret;
58}
59
60PyMODINIT_FUNC initlldb_readline(void) {
61 PyOS_ReadlineFunctionPointer = simple_readline;
62
63 return PyModule_Create(&readline_module);
64}
65#endif