GDB (xrefs)
py-gdb-readline.c
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1 /* Readline support for Python.
2 
3  Copyright (C) 2012-2015 Free Software Foundation, Inc.
4 
5  This file is part of GDB.
6 
7  This program is free software; you can redistribute it and/or modify
8  it under the terms of the GNU General Public License as published by
9  the Free Software Foundation; either version 3 of the License, or
10  (at your option) any later version.
11 
12  This program is distributed in the hope that it will be useful,
13  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  GNU General Public License for more details.
16 
17  You should have received a copy of the GNU General Public License
18  along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 
20 #include "defs.h"
21 #include "python-internal.h"
22 #include "top.h"
23 #include "cli/cli-utils.h"
24 /* Readline function suitable for PyOS_ReadlineFunctionPointer, which
25  is used for Python's interactive parser and raw_input. In both
26  cases, sys_stdin and sys_stdout are always stdin and stdout
27  respectively, as far as I can tell; they are ignored and
28  command_line_input is used instead. */
29 
30 static char *
31 gdbpy_readline_wrapper (FILE *sys_stdin, FILE *sys_stdout,
32 #if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 4
33  const char *prompt)
34 #else
35  char *prompt)
36 #endif
37 {
38  int n;
39  char *p = NULL, *q;
40 
41  TRY
42  {
43  p = command_line_input (prompt, 0, "python");
44  }
45  /* Handle errors by raising Python exceptions. */
46  CATCH (except, RETURN_MASK_ALL)
47  {
48  /* Detect user interrupt (Ctrl-C). */
49  if (except.reason == RETURN_QUIT)
50  return NULL;
51 
52  /* The thread state is nulled during gdbpy_readline_wrapper,
53  with the original value saved in the following undocumented
54  variable (see Python's Parser/myreadline.c and
55  Modules/readline.c). */
56  PyEval_RestoreThread (_PyOS_ReadlineTState);
57  gdbpy_convert_exception (except);
58  PyEval_SaveThread ();
59  return NULL;
60  }
61  END_CATCH
62 
63  /* Detect EOF (Ctrl-D). */
64  if (p == NULL)
65  {
66  q = PyMem_Malloc (1);
67  if (q != NULL)
68  q[0] = '\0';
69  return q;
70  }
71 
72  n = strlen (p);
73 
74  /* Copy the line to Python and return. */
75  q = PyMem_Malloc (n + 2);
76  if (q != NULL)
77  {
78  strncpy (q, p, n);
79  q[n] = '\n';
80  q[n + 1] = '\0';
81  }
82  return q;
83 }
84 
85 /* Initialize Python readline support. */
86 
87 void
89 {
90  /* Python's readline module conflicts with GDB's use of readline
91  since readline is not reentrant. Ideally, a reentrant wrapper to
92  GDB's readline should be implemented to replace Python's readline
93  and prevent conflicts. For now, this file implements a
94  sys.meta_path finder that simply fails to import the readline
95  module. */
96  if (PyRun_SimpleString ("\
97 import sys\n\
98 \n\
99 class GdbRemoveReadlineFinder:\n\
100  def find_module(self, fullname, path=None):\n\
101  if fullname == 'readline' and path is None:\n\
102  return self\n\
103  return None\n\
104 \n\
105  def load_module(self, fullname):\n\
106  raise ImportError('readline module disabled under GDB')\n\
107 \n\
108 sys.meta_path.append(GdbRemoveReadlineFinder())\n\
109 ") == 0)
110  PyOS_ReadlineFunctionPointer = gdbpy_readline_wrapper;
111 }
112 
#define END_CATCH
#define TRY
char * command_line_input(const char *, int, char *)
Definition: top.c:1024
#define CATCH(EXCEPTION, MASK)
void gdbpy_convert_exception(struct gdb_exception exception)
Definition: py-utils.c:295
static char * gdbpy_readline_wrapper(FILE *sys_stdin, FILE *sys_stdout, char *prompt)
void gdbpy_initialize_gdb_readline(void)