gdb/python/py-gdb-readline.c

   1 /* Readline support for Python.
   2
   3    Copyright (C) 2012-2024 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
  25 /* Readline function suitable for PyOS_ReadlineFunctionPointer, which
  26    is used for Python's interactive parser and raw_input.  In both
  27    cases, sys_stdin and sys_stdout are always stdin and stdout
  28    respectively, as far as I can tell; they are ignored and
  29    command_line_input is used instead.  */
  30
  31 static char *
  32 gdbpy_readline_wrapper (FILE *sys_stdin, FILE *sys_stdout,
  33 #if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 4
  34                         const char *prompt)
  35 #else
  36                         char *prompt)
  37 #endif
  38 {
  39   int n;
  40   const char *p = NULL;
  41   std::string buffer;
  42   char *q;
  43
  44   try
  45     {
  46       p = command_line_input (buffer, prompt, "python");
  47     }
  48   /* Handle errors by raising Python exceptions.  */
  49   catch (const gdb_exception_forced_quit &e)
  50     {
  51       quit_force (NULL, 0);
  52     }
  53   catch (const gdb_exception &except)
  54     {
  55       /* Detect user interrupt (Ctrl-C).  */
  56       if (except.reason == RETURN_QUIT)
  57         return NULL;
  58
  59
  60       /* This readline callback is called without the GIL held.  */
  61       gdbpy_gil gil;
  62
  63       gdbpy_convert_exception (except);
  64       return NULL;
  65     }
  66
  67   /* Detect EOF (Ctrl-D).  */
  68   if (p == NULL)
  69     {
  70       q = (char *) PyMem_RawMalloc (1);
  71       if (q != NULL)
  72         q[0] = '\0';
  73       return q;
  74     }
  75
  76   n = strlen (p);
  77
  78   /* Copy the line to Python and return.  */
  79   q = (char *) PyMem_RawMalloc (n + 2);
  80   if (q != NULL)
  81     {
  82       strcpy (q, p);
  83       q[n] = '\n';
  84       q[n + 1] = '\0';
  85     }
  86   return q;
  87 }
  88
  89 /* Initialize Python readline support.  */
  90
  91 static int CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION
  92 gdbpy_initialize_gdb_readline (void)
  93 {
  94   /* Python's readline module conflicts with GDB's use of readline
  95      since readline is not reentrant.  Ideally, a reentrant wrapper to
  96      GDB's readline should be implemented to replace Python's readline
  97      and prevent conflicts.  For now, this file implements a
  98      sys.meta_path finder that simply fails to import the readline
  99      module.  */
 100   if (PyRun_SimpleString ("\
 101 import sys\n\
 102 \n\
 103 class GdbRemoveReadlineFinder:\n\
 104   def find_module(self, fullname, path=None):\n\
 105     if fullname == 'readline' and path is None:\n\
 106       return self\n\
 107     return None\n\
 108 \n\
 109   def load_module(self, fullname):\n\
 110     raise ImportError('readline module disabled under GDB')\n\
 111 \n\
 112 sys.meta_path.append(GdbRemoveReadlineFinder())\n\
 113 ") == 0)
 114     PyOS_ReadlineFunctionPointer = gdbpy_readline_wrapper;
 115
 116   return 0;
 117 }
 118
 119 GDBPY_INITIALIZE_FILE (gdbpy_initialize_gdb_readline);