gdb/python/py-gdb-readline.c - gdb

Functions defined

Source code

  1. /* Readline support for Python.

  3.    Copyright (C) 2012-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  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.

  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.

  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/>.  */

  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.  */

  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.   volatile struct gdb_exception except;

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

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

  49.   /* Handle errors by raising Python exceptions.  */
  50.   if (except.reason < 0)
  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.     }

  62.   /* Detect EOF (Ctrl-D).  */
  63.   if (p == NULL)
  64.     {
  65.       q = PyMem_Malloc (1);
  66.       if (q != NULL)
  67.         q[0] = '\0';
  68.       return q;
  69.     }

  71.   n = strlen (p);

  73.   /* Copy the line to Python and return.  */
  74.   q = PyMem_Malloc (n + 2);
  75.   if (q != NULL)
  76.     {
  77.       strncpy (q, p, n);
  78.       q[n] = '\n';
  79.       q[n + 1] = '\0';
  80.     }
  81.   return q;
  82. }

  84. /* Initialize Python readline support.  */

  86. void
  87. ‌gdbpy_initialize_gdb_readline (void)
  88. {
  89.   /* Python's readline module conflicts with GDB's use of readline
  90.      since readline is not reentrant.  Ideally, a reentrant wrapper to
  91.      GDB's readline should be implemented to replace Python's readline
  92.      and prevent conflicts.  For now, this file implements a
  93.      sys.meta_path finder that simply fails to import the readline
  94.      module.  */
  95.   if (PyRun_SimpleString ("\
  96. import sys\n\
  97. \n\
  98. class GdbRemoveReadlineFinder:\n\
  99.   def find_module(self, fullname, path=None):\n\
  100.     if fullname == 'readline' and path is None:\n\
  101.       return self\n\
  102.     return None\n\
  103. \n\
  104.   def load_module(self, fullname):\n\
  105.     raise ImportError('readline module disabled under GDB')\n\
  106. \n\
  107. sys.meta_path.append(GdbRemoveReadlineFinder())\n\
  108. ") == 0)
  109.     PyOS_ReadlineFunctionPointer = gdbpy_readline_wrapper;
  110. }