source4/web_server/wsgi.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright © Jelmer Vernooij <jelmer@samba.org> 2008
   5
   6    Implementation of the WSGI interface described in PEP0333
   7    (http://www.python.org/dev/peps/pep-0333)
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include <Python.h>
  24 #include "includes.h"
  25 #include "web_server/web_server.h"
  26 #include "../lib/util/dlinklist.h"
  27 #include "lib/tls/tls.h"
  28 #include "lib/tsocket/tsocket.h"
  29 #include "python/modules.h"
  30 #include "python/py3compat.h"
  31
  32 typedef struct {
  33         PyObject_HEAD
  34         struct websrv_context *web;
  35 } web_request_Object;
  36
  37 static PyObject *start_response(PyObject *self, PyObject *args, PyObject *kwargs)
  38 {
  39         PyObject *response_header, *exc_info = NULL;
  40         char *status;
  41         Py_ssize_t i;
  42         const char *kwnames[] = {
  43                 "status", "response_header", "exc_info", NULL
  44         };
  45         web_request_Object *py_web = (web_request_Object *)self;
  46         struct websrv_context *web = py_web->web;
  47         struct http_header *headers = NULL;
  48
  49         if (!PyArg_ParseTupleAndKeywords(args, kwargs, "sO|O:start_response", discard_const_p(char *, kwnames), &status, &response_header, &exc_info)) {
  50                 return NULL;
  51         }
  52
  53         /* FIXME: exc_info */
  54
  55         if (!PyList_Check(response_header)) {
  56                 PyErr_SetString(PyExc_TypeError, "response_header should be list");
  57                 return NULL;
  58         }
  59
  60         for (i = 0; i < PyList_Size(response_header); i++) {
  61                 struct http_header *hdr = talloc_zero(web, struct http_header);
  62                 PyObject *item = PyList_GetItem(response_header, i);
  63                 PyObject *py_name, *py_value;
  64
  65                 if (!PyTuple_Check(item)) {
  66                         PyErr_SetString(PyExc_TypeError, "Expected tuple");
  67                         return NULL;
  68                 }
  69
  70                 if (PyTuple_Size(item) != 2) {
  71                         PyErr_SetString(PyExc_TypeError, "header tuple has invalid size, expected 2");
  72                         return NULL;
  73                 }
  74
  75                 py_name = PyTuple_GetItem(item, 0);
  76
  77                 if (!PyStr_Check(py_name)) {
  78                         PyErr_SetString(PyExc_TypeError, "header name should be string");
  79                         return NULL;
  80                 }
  81
  82                 py_value = PyTuple_GetItem(item, 1);
  83                 if (!PyStr_Check(py_value)) {
  84                         PyErr_SetString(PyExc_TypeError, "header value should be string");
  85                         return NULL;
  86                 }
  87
  88                 hdr->name = talloc_strdup(hdr, PyStr_AsString(py_name));
  89                 hdr->value = talloc_strdup(hdr, PyStr_AsString(py_value));
  90                 DLIST_ADD(headers, hdr);
  91         }
  92
  93         websrv_output_headers(web, status, headers);
  94
  95         Py_RETURN_NONE;
  96 }
  97
  98 static PyMethodDef web_request_methods[] = {
  99         { "start_response", (PyCFunction)start_response, METH_VARARGS|METH_KEYWORDS, NULL },
 100         { NULL }
 101 };
 102
 103
 104 PyTypeObject web_request_Type = {
 105         PyVarObject_HEAD_INIT(NULL, 0)
 106         .tp_name = "wsgi.Request",
 107         .tp_methods = web_request_methods,
 108         .tp_basicsize = sizeof(web_request_Object),
 109         .tp_flags = Py_TPFLAGS_DEFAULT,
 110 };
 111
 112 typedef struct {
 113         PyObject_HEAD
 114 } error_Stream_Object;
 115
 116 static PyObject *py_error_flush(PyObject *self, PyObject *args, PyObject *kwargs)
 117 {
 118         /* Nothing to do here */
 119         Py_RETURN_NONE;
 120 }
 121
 122 static PyObject *py_error_write(PyObject *self, PyObject *args, PyObject *kwargs)
 123 {
 124         const char *kwnames[] = { "str", NULL };
 125         char *str = NULL;
 126
 127         if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s:write", discard_const_p(char *, kwnames), &str)) {
 128                 return NULL;
 129         }
 130
 131         DEBUG(0, ("%s", str));
 132
 133         Py_RETURN_NONE;
 134 }
 135
 136 static PyObject *py_error_writelines(PyObject *self, PyObject *args, PyObject *kwargs)
 137 {
 138         const char *kwnames[] = { "seq", NULL };
 139         PyObject *seq = NULL, *item;
 140
 141         if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O:writelines", discard_const_p(char *, kwnames), &seq)) {
 142                 return NULL;
 143         }
 144
 145         while ((item = PyIter_Next(seq))) {
 146                 const char *str = NULL;
 147                 Py_ssize_t size = 0;
 148                 if (!IsPy3Bytes(item)) {
 149                         str = PyStr_AsUTF8AndSize(item, &size);
 150                 } else {
 151                         str = PyBytes_AsString(item);
 152                         size = PyBytes_Size(item);
 153                 }
 154                 if (size > 0) {
 155                         DEBUG(0, ("%s", str));
 156                 }
 157         }
 158
 159         Py_RETURN_NONE;
 160 }
 161
 162 static PyMethodDef error_Stream_methods[] = {
 163         { "flush", (PyCFunction)py_error_flush, METH_VARARGS|METH_KEYWORDS, NULL },
 164         { "write", (PyCFunction)py_error_write, METH_VARARGS|METH_KEYWORDS, NULL },
 165         { "writelines", (PyCFunction)py_error_writelines, METH_VARARGS|METH_KEYWORDS, NULL },
 166         { NULL, NULL, 0, NULL }
 167 };
 168
 169 PyTypeObject error_Stream_Type = {
 170         PyVarObject_HEAD_INIT(NULL, 0)
 171         .tp_name = "wsgi.ErrorStream",
 172         .tp_basicsize = sizeof(error_Stream_Object),
 173         .tp_methods = error_Stream_methods,
 174         .tp_flags = Py_TPFLAGS_DEFAULT,
 175 };
 176
 177 typedef struct {
 178         PyObject_HEAD
 179         struct websrv_context *web;
 180         size_t offset;
 181 } input_Stream_Object;
 182
 183 static PyObject *py_input_read(PyObject *_self, PyObject *args, PyObject *kwargs)
 184 {
 185         const char *kwnames[] = { "size", NULL };
 186         PyObject *ret;
 187         input_Stream_Object *self = (input_Stream_Object *)_self;
 188         int size = -1;
 189
 190         if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|i", discard_const_p(char *, kwnames), &size))
 191                 return NULL;
 192
 193         /* Don't read beyond buffer boundaries */
 194         if (size == -1)
 195                 size = self->web->input.partial.length-self->offset;
 196         else
 197                 size = MIN(size, self->web->input.partial.length-self->offset);
 198
 199         ret = PyBytes_FromStringAndSize((char *)self->web->input.partial.data+self->offset, size);
 200         self->offset += size;
 201
 202         return ret;
 203 }
 204
 205 static PyObject *py_input_readline(PyObject *_self)
 206 {
 207         /* FIXME */
 208         PyErr_SetString(PyExc_NotImplementedError,
 209                         "readline() not yet implemented");
 210         return NULL;
 211 }
 212
 213 static PyObject *py_input_readlines(PyObject *_self, PyObject *args, PyObject *kwargs)
 214 {
 215         const char *kwnames[] = { "hint", NULL };
 216         int hint = 0;
 217
 218         if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|i", discard_const_p(char *, kwnames), &hint))
 219                 return NULL;
 220
 221         /* FIXME */
 222         PyErr_SetString(PyExc_NotImplementedError,
 223                         "readlines() not yet implemented");
 224         return NULL;
 225 }
 226
 227 static PyObject *py_input___iter__(PyObject *_self)
 228 {
 229         /* FIXME */
 230         PyErr_SetString(PyExc_NotImplementedError,
 231                         "__iter__() not yet implemented");
 232         return NULL;
 233 }
 234
 235 static PyMethodDef input_Stream_methods[] = {
 236         { "read", (PyCFunction)py_input_read, METH_VARARGS|METH_KEYWORDS, NULL },
 237         { "readline", (PyCFunction)py_input_readline, METH_NOARGS, NULL },
 238         { "readlines", (PyCFunction)py_input_readlines, METH_VARARGS|METH_KEYWORDS, NULL },
 239         { "__iter__", (PyCFunction)py_input___iter__, METH_NOARGS, NULL },
 240         { NULL, NULL, 0, NULL }
 241 };
 242
 243 PyTypeObject input_Stream_Type = {
 244         PyVarObject_HEAD_INIT(NULL, 0)
 245         .tp_name = "wsgi.InputStream",
 246         .tp_basicsize = sizeof(input_Stream_Object),
 247         .tp_methods = input_Stream_methods,
 248         .tp_flags = Py_TPFLAGS_DEFAULT,
 249 };
 250
 251 static PyObject *Py_InputHttpStream(struct websrv_context *web)
 252 {
 253         input_Stream_Object *ret = PyObject_New(input_Stream_Object, &input_Stream_Type);
 254         ret->web = web;
 255         ret->offset = 0;
 256         return (PyObject *)ret;
 257 }
 258
 259 static PyObject *Py_ErrorHttpStream(void)
 260 {
 261         error_Stream_Object *ret = PyObject_New(error_Stream_Object, &error_Stream_Type);
 262         return (PyObject *)ret;
 263 }
 264
 265 static void DEBUG_Print_PyError(int level, const char *message)
 266 {
 267         PyObject *old_stderr, *new_stderr;
 268         PyObject *sys_module;
 269         PyObject *ptype, *pvalue, *ptb;
 270
 271         PyErr_Fetch(&ptype, &pvalue, &ptb);
 272
 273         DEBUG(0, ("WSGI: Server exception occurred: %s\n", message));
 274
 275         sys_module = PyImport_ImportModule("sys");
 276         if (sys_module == NULL) {
 277                 DEBUG(0, ("Unable to obtain sys module while printing error"));
 278                 return;
 279         }
 280
 281         old_stderr = PyObject_GetAttrString(sys_module, "stderr");
 282         if (old_stderr == NULL) {
 283                 DEBUG(0, ("Unable to obtain old stderr"));
 284                 Py_DECREF(sys_module);
 285                 return;
 286         }
 287
 288         new_stderr = Py_ErrorHttpStream();
 289         if (new_stderr == NULL) {
 290                 DEBUG(0, ("Unable to create error stream"));
 291                 Py_DECREF(sys_module);
 292                 Py_DECREF(old_stderr);
 293                 return;
 294         }
 295
 296         PyObject_SetAttrString(sys_module, "stderr", new_stderr);
 297         Py_DECREF(new_stderr);
 298
 299         PyErr_Restore(ptype, pvalue, ptb);
 300         PyErr_Print();
 301
 302         PyObject_SetAttrString(sys_module, "stderr", old_stderr);
 303         Py_DECREF(old_stderr);
 304
 305         Py_DECREF(sys_module);
 306 }
 307
 308 static PyObject *create_environ(bool tls, int content_length, struct http_header *headers, const char *request_method, const char *servername, int serverport, PyObject *inputstream, const char *request_string)
 309 {
 310         PyObject *env;
 311         PyObject *py_scheme;
 312         PyObject *py_val;
 313         struct http_header *hdr;
 314         char *questionmark;
 315
 316         env = PyDict_New();
 317         if (env == NULL) {
 318                 return NULL;
 319         }
 320
 321         PyDict_SetItemString(env, "wsgi.input", inputstream);
 322
 323         py_val = Py_ErrorHttpStream();
 324         if (py_val == NULL) goto error;
 325         PyDict_SetItemString(env, "wsgi.errors", py_val);
 326         Py_DECREF(py_val);
 327
 328         py_val = Py_BuildValue("(i,i)", 1, 0);
 329         if (py_val == NULL) goto error;
 330         PyDict_SetItemString(env, "wsgi.version", py_val);
 331         Py_DECREF(py_val);
 332         PyDict_SetItemString(env, "wsgi.multithread", Py_False);
 333         PyDict_SetItemString(env, "wsgi.multiprocess", Py_False);
 334         PyDict_SetItemString(env, "wsgi.run_once", Py_False);
 335         py_val = PyStr_FromString("HTTP/1.0");
 336         if (py_val == NULL) goto error;
 337         PyDict_SetItemString(env, "SERVER_PROTOCOL", py_val);
 338         Py_DECREF(py_val);
 339         if (content_length > 0) {
 340                 py_val = PyLong_FromLong(content_length);
 341                 if (py_val == NULL) goto error;
 342                 PyDict_SetItemString(env, "CONTENT_LENGTH", py_val);
 343                 Py_DECREF(py_val);
 344         }
 345         py_val = PyStr_FromString(request_method);
 346         if (py_val == NULL) goto error;
 347         PyDict_SetItemString(env, "REQUEST_METHOD", py_val);
 348         Py_DECREF(py_val);
 349
 350         /* There is always a single wsgi app to which all requests are redirected,
 351          * so SCRIPT_NAME will be / */
 352         py_val = PyStr_FromString("/");
 353         if (py_val == NULL) goto error;
 354         PyDict_SetItemString(env, "SCRIPT_NAME", py_val);
 355         Py_DECREF(py_val);
 356         questionmark = strchr(request_string, '?');
 357         if (questionmark == NULL) {
 358                 py_val = PyStr_FromString(request_string);
 359                 if (py_val == NULL) goto error;
 360                 PyDict_SetItemString(env, "PATH_INFO", py_val);
 361                 Py_DECREF(py_val);
 362         } else {
 363                 py_val = PyStr_FromString(questionmark+1);
 364                 if (py_val == NULL) goto error;
 365                 PyDict_SetItemString(env, "QUERY_STRING", py_val);
 366                 Py_DECREF(py_val);
 367                 py_val = PyStr_FromStringAndSize(request_string, questionmark-request_string);
 368                 if (py_val == NULL) goto error;
 369                 PyDict_SetItemString(env, "PATH_INFO", py_val);
 370                 Py_DECREF(py_val);
 371         }
 372
 373         py_val = PyStr_FromString(servername);
 374         if (py_val == NULL) goto error;
 375         PyDict_SetItemString(env, "SERVER_NAME", py_val);
 376         Py_DECREF(py_val);
 377         py_val = PyStr_FromFormat("%d", serverport);
 378         if (py_val == NULL) goto error;
 379         PyDict_SetItemString(env, "SERVER_PORT", py_val);
 380         Py_DECREF(py_val);
 381
 382         for (hdr = headers; hdr; hdr = hdr->next) {
 383                 char *name;
 384                 if (!strcasecmp(hdr->name, "Content-Type")) {
 385                         py_val = PyStr_FromString(hdr->value);
 386                         PyDict_SetItemString(env, "CONTENT_TYPE", py_val);
 387                         Py_DECREF(py_val);
 388                 } else {
 389                         if (asprintf(&name, "HTTP_%s", hdr->name) < 0) {
 390                                 PyErr_NoMemory();
 391                                 goto error;
 392                         }
 393                         py_val = PyStr_FromString(hdr->value);
 394                         PyDict_SetItemString(env, name, py_val);
 395                         Py_DECREF(py_val);
 396                         free(name);
 397                 }
 398         }
 399
 400         if (tls) {
 401                 py_scheme = PyStr_FromString("https");
 402         } else {
 403                 py_scheme = PyStr_FromString("http");
 404         }
 405         if (py_scheme == NULL) goto error;
 406         PyDict_SetItemString(env, "wsgi.url_scheme", py_scheme);
 407         Py_DECREF(py_scheme);
 408
 409         return env;
 410 error:
 411         Py_DECREF(env);
 412         return NULL;
 413 }
 414
 415 static void wsgi_serve_500(struct websrv_context *web)
 416 {
 417         struct http_header *headers = NULL;
 418         const char *contents[] = {
 419                 "An internal server error occurred while handling this request. ",
 420                 "Please refer to the server logs for more details. ",
 421                 NULL
 422         };
 423         int i;
 424
 425         websrv_output_headers(web, "500 Internal Server Error", headers);
 426         for (i = 0; contents[i]; i++) {
 427                 websrv_output(web, contents[i], strlen(contents[i]));
 428         }
 429 }
 430
 431 static void wsgi_process_http_input(struct web_server_data *wdata,
 432                                     struct websrv_context *web)
 433 {
 434         PyObject *py_environ, *result, *item, *iter;
 435         PyObject *request_handler = (PyObject *)wdata->private_data;
 436         struct tsocket_address *my_address = web->conn->local_address;
 437         const char *addr = "0.0.0.0";
 438         uint16_t port = 0;
 439         web_request_Object *py_web;
 440         PyObject *py_input_stream;
 441
 442         py_web = PyObject_New(web_request_Object, &web_request_Type);
 443         if (py_web == NULL) {
 444                 DEBUG_Print_PyError(0, "Unable to allocate web request");
 445                 return;
 446         }
 447         py_web->web = web;
 448
 449         if (tsocket_address_is_inet(my_address, "ip")) {
 450                 addr = tsocket_address_inet_addr_string(my_address, wdata);
 451                 port = tsocket_address_inet_port(my_address);
 452         }
 453
 454         py_input_stream = Py_InputHttpStream(web);
 455         if (py_input_stream == NULL) {
 456                 DEBUG_Print_PyError(0, "unable to create python input stream");
 457                 return;
 458         }
 459
 460         py_environ = create_environ(tls_enabled(web->conn->socket),
 461                                     web->input.content_length,
 462                                     web->input.headers,
 463                                     web->input.post_request?"POST":"GET",
 464                                     addr,
 465                                     port,
 466                                     py_input_stream,
 467                                     web->input.url
 468                                     );
 469
 470         Py_DECREF(py_input_stream);
 471
 472         if (py_environ == NULL) {
 473                 DEBUG_Print_PyError(0, "Unable to create WSGI environment object");
 474                 wsgi_serve_500(web);
 475                 return;
 476         }
 477
 478         result = PyObject_CallMethod(request_handler, discard_const_p(char, "__call__"), discard_const_p(char, "OO"),
 479                                        py_environ, PyObject_GetAttrString((PyObject *)py_web, "start_response"));
 480
 481         if (result == NULL) {
 482                 DEBUG_Print_PyError(0, "error while handling request");
 483                 wsgi_serve_500(web);
 484                 return;
 485         }
 486
 487         iter = PyObject_GetIter(result);
 488         Py_DECREF(result);
 489
 490         if (iter == NULL) {
 491                 DEBUG_Print_PyError(0, "application did not return iterable");
 492                 wsgi_serve_500(web);
 493                 return;
 494         }
 495
 496         /* Now, iter over all the data returned */
 497
 498         while ((item = PyIter_Next(iter))) {
 499                 Py_ssize_t size = 0;
 500                 char *value = NULL;
 501                 int ret = PyBytes_AsStringAndSize(item, &value, &size);
 502                 if (ret == -1) {
 503                         DEBUG_Print_PyError(0, "application failed to "
 504                                 "extract string from iterable");
 505                         wsgi_serve_500(web);
 506                         return;
 507                 }
 508                 websrv_output(web, value, size);
 509                 Py_DECREF(item);
 510         }
 511
 512         Py_DECREF(iter);
 513 }
 514
 515 bool wsgi_initialize(struct web_server_data *wdata)
 516 {
 517         PyObject *py_web_server;
 518
 519         Py_Initialize();
 520
 521         py_update_path(); /* Ensure that we have the Samba paths at
 522                            * the start of the sys.path() */
 523
 524         if (PyType_Ready(&web_request_Type) < 0)
 525                 return false;
 526
 527         if (PyType_Ready(&input_Stream_Type) < 0)
 528                 return false;
 529
 530         if (PyType_Ready(&error_Stream_Type) < 0)
 531                 return false;
 532
 533         wdata->http_process_input = wsgi_process_http_input;
 534         py_web_server = PyImport_ImportModule("samba.web_server");
 535         if (py_web_server == NULL) {
 536                 DEBUG_Print_PyError(0, "Unable to find web server");
 537                 return false;
 538         }
 539         wdata->private_data = py_web_server;
 540         return true;
 541 }