plugins/python/modfunctions.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /* Functions and constants in the virtual nbdkit.* module. */
  34
  35 #include <config.h>
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39
  40 #include "plugin.h"
  41
  42 __thread int last_error;
  43
  44 /* nbdkit.debug */
  45 static PyObject *
  46 debug (PyObject *self, PyObject *args)
  47 {
  48   const char *msg;
  49
  50   if (!PyArg_ParseTuple (args, "s:debug", &msg))
  51     return NULL;
  52   nbdkit_debug ("%s", msg);
  53   Py_RETURN_NONE;
  54 }
  55
  56 /* nbdkit.export_name */
  57 static PyObject *
  58 export_name (PyObject *self, PyObject *args)
  59 {
  60   const char *s = nbdkit_export_name ();
  61
  62   if (!s) {
  63     /* Unfortunately we lose the actual error. XXX */
  64     PyErr_SetString (PyExc_RuntimeError, "nbdkit.export_name failed");
  65     return NULL;
  66   }
  67
  68   /* NBD spec says that the export name should be UTF-8, so this
  69    * ought to work, and if it fails the client gave us a bad export
  70    * name which should turn into an exception.
  71    */
  72   return PyUnicode_FromString (s);
  73 }
  74
  75 /* nbdkit.set_error */
  76 static PyObject *
  77 set_error (PyObject *self, PyObject *args)
  78 {
  79   int err;
  80
  81   if (!PyArg_ParseTuple (args, "i:set_error", &err))
  82     return NULL;
  83   nbdkit_set_error (err);
  84   last_error = err;
  85   Py_RETURN_NONE;
  86 }
  87
  88 /* nbdkit.shutdown */
  89 static PyObject *
  90 do_shutdown (PyObject *self, PyObject *args)
  91 {
  92   nbdkit_shutdown ();
  93   Py_RETURN_NONE;
  94 }
  95
  96 /* nbdkit.disconnect */
  97 static PyObject *
  98 do_disconnect (PyObject *self, PyObject *args)
  99 {
 100   int force;
 101
 102   if (!PyArg_ParseTuple (args, "p:disconnect", &force))
 103     return NULL;
 104   nbdkit_disconnect (force);
 105   Py_RETURN_NONE;
 106 }
 107
 108 /* nbdkit.parse_size */
 109 static PyObject *
 110 parse_size (PyObject *self, PyObject *args)
 111 {
 112   const char *s;
 113   if (!PyArg_ParseTuple (args, "s:parse_size", &s))
 114     return NULL;
 115
 116   int64_t size = nbdkit_parse_size (s);
 117   if (size == -1) {
 118     PyErr_SetString (PyExc_ValueError, "Unable to parse string as size");
 119     return NULL;
 120   }
 121
 122   return PyLong_FromSize_t ((size_t)size);
 123 }
 124
 125 static PyMethodDef NbdkitMethods[] = {
 126   { "debug", debug, METH_VARARGS,
 127     "Print a debug message" },
 128   { "export_name", export_name, METH_NOARGS,
 129     "Return the optional export name negotiated with the client" },
 130   { "parse_size", parse_size, METH_VARARGS,
 131     "Parse human-readable size strings into bytes" },
 132   { "set_error", set_error, METH_VARARGS,
 133     "Store an errno value prior to throwing an exception" },
 134   { "shutdown", do_shutdown, METH_NOARGS,
 135     "Request asynchronous shutdown" },
 136   { "disconnect", do_disconnect, METH_VARARGS,
 137     "Request disconnection from current client" },
 138   { NULL }
 139 };
 140
 141 static struct PyModuleDef moduledef = {
 142   PyModuleDef_HEAD_INIT,
 143   "nbdkit",
 144   "Module used to access nbdkit server API",
 145   -1,
 146   NbdkitMethods,
 147   NULL,
 148   NULL,
 149   NULL,
 150   NULL
 151 };
 152
 153 PyMODINIT_FUNC
 154 create_nbdkit_module (void)
 155 {
 156   PyObject *m;
 157
 158   m = PyModule_Create (&moduledef);
 159   if (m == NULL) {
 160     nbdkit_error ("could not create the nbdkit API module");
 161     exit (EXIT_FAILURE);
 162   }
 163
 164   /* Constants corresponding to various flags. */
 165 #define ADD_INT_CONSTANT(name)                                      \
 166   if (PyModule_AddIntConstant (m, #name, NBDKIT_##name) == -1) {    \
 167     nbdkit_error ("could not add constant %s to nbdkit API module", \
 168                   #name);                                           \
 169     exit (EXIT_FAILURE);                                            \
 170   }
 171   ADD_INT_CONSTANT (THREAD_MODEL_SERIALIZE_CONNECTIONS);
 172   ADD_INT_CONSTANT (THREAD_MODEL_SERIALIZE_ALL_REQUESTS);
 173   ADD_INT_CONSTANT (THREAD_MODEL_SERIALIZE_REQUESTS);
 174   ADD_INT_CONSTANT (THREAD_MODEL_PARALLEL);
 175
 176   ADD_INT_CONSTANT (FLAG_MAY_TRIM);
 177   ADD_INT_CONSTANT (FLAG_FUA);
 178   ADD_INT_CONSTANT (FLAG_REQ_ONE);
 179   ADD_INT_CONSTANT (FLAG_FAST_ZERO);
 180
 181   ADD_INT_CONSTANT (FUA_NONE);
 182   ADD_INT_CONSTANT (FUA_EMULATE);
 183   ADD_INT_CONSTANT (FUA_NATIVE);
 184
 185   ADD_INT_CONSTANT (CACHE_NONE);
 186   ADD_INT_CONSTANT (CACHE_EMULATE);
 187   ADD_INT_CONSTANT (CACHE_NATIVE);
 188
 189   ADD_INT_CONSTANT (EXTENT_HOLE);
 190   ADD_INT_CONSTANT (EXTENT_ZERO);
 191 #undef ADD_INT_CONSTANT
 192
 193   return m;
 194 }