aboutsummaryrefslogtreecommitdiff
path: root/gdb/python/py-gdb-readline.c
blob: e926f8e1460eefa5c4c03927a097982834fd9a7c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
/* Readline support for Python.

   Copyright (C) 2012-2014 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "python-internal.h"
#include "exceptions.h"
#include "top.h"
#include "cli/cli-utils.h"
#include <string.h>

#include <stddef.h>

/* Readline function suitable for PyOS_ReadlineFunctionPointer, which
   is used for Python's interactive parser and raw_input.  In both
   cases, sys_stdin and sys_stdout are always stdin and stdout
   respectively, as far as I can tell; they are ignored and
   command_line_input is used instead.  */

static char *
gdbpy_readline_wrapper (FILE *sys_stdin, FILE *sys_stdout,
			char *prompt)
{
  int n;
  char *p = NULL, *q;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    p = command_line_input (prompt, 0, "python");

  /* Detect user interrupt (Ctrl-C).  */
  if (except.reason == RETURN_QUIT)
    return NULL;

  /* Handle errors by raising Python exceptions.  */
  if (except.reason < 0)
    {
      /* The thread state is nulled during gdbpy_readline_wrapper,
	 with the original value saved in the following undocumented
	 variable (see Python's Parser/myreadline.c and
	 Modules/readline.c).  */
      PyEval_RestoreThread (_PyOS_ReadlineTState);
      gdbpy_convert_exception (except);
      PyEval_SaveThread ();
      return NULL;
    }

  /* Detect EOF (Ctrl-D).  */
  if (p == NULL)
    {
      q = PyMem_Malloc (1);
      if (q != NULL)
	q[0] = '\0';
      return q;
    }

  n = strlen (p);

  /* Copy the line to Python and return.  */
  q = PyMem_Malloc (n + 2);
  if (q != NULL)
    {
      strncpy (q, p, n);
      q[n] = '\n';
      q[n + 1] = '\0';
    }
  return q;
}

/* Initialize Python readline support.  */

void
gdbpy_initialize_gdb_readline (void)
{
  /* Python's readline module conflicts with GDB's use of readline
     since readline is not reentrant.  Ideally, a reentrant wrapper to
     GDB's readline should be implemented to replace Python's readline
     and prevent conflicts.  For now, this file implements a
     sys.meta_path finder that simply fails to import the readline
     module.  */
  if (PyRun_SimpleString ("\
import sys\n\
\n\
class GdbRemoveReadlineFinder:\n\
  def find_module(self, fullname, path=None):\n\
    if fullname == 'readline' and path is None:\n\
      return self\n\
    return None\n\
\n\
  def load_module(self, fullname):\n\
    raise ImportError('readline module disabled under GDB')\n\
\n\
sys.meta_path.append(GdbRemoveReadlineFinder())\n\
") == 0)
    PyOS_ReadlineFunctionPointer = gdbpy_readline_wrapper;
}