gdb/python/py-membuf.c

   1 /* Python memory buffer interface for reading inferior memory.
   2
   3    Copyright (C) 2009-2023 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
  23 struct membuf_object {
  24   PyObject_HEAD
  25
  26   /* Pointer to the raw data, and array of gdb_bytes.  */
  27   void *buffer;
  28
  29   /* The address from where the data was read, held for mbpy_str.  */
  30   CORE_ADDR addr;
  31
  32   /* The number of octets in BUFFER.  */
  33   CORE_ADDR length;
  34 };
  35
  36 extern PyTypeObject membuf_object_type
  37     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("membuf_object");
  38
  39 /* Wrap BUFFER, ADDRESS, and LENGTH into a gdb.Membuf object.  ADDRESS is
  40    the address within the inferior that the contents of BUFFER were read,
  41    and LENGTH is the number of octets in BUFFER.  */
  42
  43 PyObject *
  44 gdbpy_buffer_to_membuf (gdb::unique_xmalloc_ptr<gdb_byte> buffer,
  45                         CORE_ADDR address,
  46                         ULONGEST length)
  47 {
  48   gdbpy_ref<membuf_object> membuf_obj (PyObject_New (membuf_object,
  49                                                      &membuf_object_type));
  50   if (membuf_obj == nullptr)
  51     return nullptr;
  52
  53   membuf_obj->buffer = buffer.release ();
  54   membuf_obj->addr = address;
  55   membuf_obj->length = length;
  56
  57   return PyMemoryView_FromObject ((PyObject *) membuf_obj.get ());
  58 }
  59
  60 /* Destructor for gdb.Membuf objects.  */
  61
  62 static void
  63 mbpy_dealloc (PyObject *self)
  64 {
  65   xfree (((membuf_object *) self)->buffer);
  66   Py_TYPE (self)->tp_free (self);
  67 }
  68
  69 /* Return a description of the gdb.Membuf object.  */
  70
  71 static PyObject *
  72 mbpy_str (PyObject *self)
  73 {
  74   membuf_object *membuf_obj = (membuf_object *) self;
  75
  76   return PyUnicode_FromFormat (_("Memory buffer for address %s, \
  77 which is %s bytes long."),
  78                                paddress (gdbpy_enter::get_gdbarch (),
  79                                          membuf_obj->addr),
  80                                pulongest (membuf_obj->length));
  81 }
  82
  83 static int
  84 get_buffer (PyObject *self, Py_buffer *buf, int flags)
  85 {
  86   membuf_object *membuf_obj = (membuf_object *) self;
  87   int ret;
  88
  89   ret = PyBuffer_FillInfo (buf, self, membuf_obj->buffer,
  90                            membuf_obj->length, 0,
  91                            PyBUF_CONTIG);
  92
  93   /* Despite the documentation saying this field is a "const char *",
  94      in Python 3.4 at least, it's really a "char *".  */
  95   buf->format = (char *) "c";
  96
  97   return ret;
  98 }
  99
 100 /* General Python initialization callback.  */
 101
 102 int
 103 gdbpy_initialize_membuf (void)
 104 {
 105   membuf_object_type.tp_new = PyType_GenericNew;
 106   if (PyType_Ready (&membuf_object_type) < 0)
 107     return -1;
 108
 109   return gdb_pymodule_addobject (gdb_module, "Membuf",
 110                                  (PyObject *) &membuf_object_type);
 111 }
 112
 113 static PyBufferProcs buffer_procs =
 114 {
 115   get_buffer
 116 };
 117
 118 PyTypeObject membuf_object_type = {
 119   PyVarObject_HEAD_INIT (nullptr, 0)
 120   "gdb.Membuf",                   /*tp_name*/
 121   sizeof (membuf_object),         /*tp_basicsize*/
 122   0,                              /*tp_itemsize*/
 123   mbpy_dealloc,                   /*tp_dealloc*/
 124   0,                              /*tp_print*/
 125   0,                              /*tp_getattr*/
 126   0,                              /*tp_setattr*/
 127   0,                              /*tp_compare*/
 128   0,                              /*tp_repr*/
 129   0,                              /*tp_as_number*/
 130   0,                              /*tp_as_sequence*/
 131   0,                              /*tp_as_mapping*/
 132   0,                              /*tp_hash */
 133   0,                              /*tp_call*/
 134   mbpy_str,                       /*tp_str*/
 135   0,                              /*tp_getattro*/
 136   0,                              /*tp_setattro*/
 137   &buffer_procs,                  /*tp_as_buffer*/
 138   Py_TPFLAGS_DEFAULT,             /*tp_flags*/
 139   "GDB memory buffer object",     /*tp_doc*/
 140   0,                              /* tp_traverse */
 141   0,                              /* tp_clear */
 142   0,                              /* tp_richcompare */
 143   0,                              /* tp_weaklistoffset */
 144   0,                              /* tp_iter */
 145   0,                              /* tp_iternext */
 146   0,                              /* tp_methods */
 147   0,                              /* tp_members */
 148   0,                              /* tp_getset */
 149   0,                              /* tp_base */
 150   0,                              /* tp_dict */
 151   0,                              /* tp_descr_get */
 152   0,                              /* tp_descr_set */
 153   0,                              /* tp_dictoffset */
 154   0,                              /* tp_init */
 155   0,                              /* tp_alloc */
 156 };