libsigrokdecode  0.2.0
sigrok protocol decoding library
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decoder.c
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1 /*
2  * This file is part of the libsigrokdecode project.
3  *
4  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
5  * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
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 
21 #include "config.h"
22 #include "libsigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
23 #include "libsigrokdecode-internal.h"
24 #include <glib.h>
25 
26 /**
27  * @file
28  *
29  * Listing, loading, unloading, and handling protocol decoders.
30  */
31 
32 /**
33  * @defgroup grp_decoder Protocol decoders
34  *
35  * Handling protocol decoders.
36  *
37  * @{
38  */
39 
40 /** @cond PRIVATE */
41 
42 /* The list of protocol decoders. */
43 SRD_PRIV GSList *pd_list = NULL;
44 
45 /* module_sigrokdecode.c */
46 extern SRD_PRIV PyObject *mod_sigrokdecode;
47 
48 /** @endcond */
49 
50 /**
51  * Returns the list of supported/loaded protocol decoders.
52  *
53  * This is a GSList containing the names of the decoders as strings.
54  *
55  * @return List of decoders, NULL if none are supported or loaded.
56  *
57  * @since 0.1.0 (but the API changed in 0.2.0)
58  */
59 SRD_API const GSList *srd_decoder_list(void)
60 {
61  return pd_list;
62 }
63 
64 /**
65  * Get the decoder with the specified ID.
66  *
67  * @param id The ID string of the decoder to return.
68  *
69  * @return The decoder with the specified ID, or NULL if not found.
70  *
71  * @since 0.1.0
72  */
73 SRD_API struct srd_decoder *srd_decoder_get_by_id(const char *id)
74 {
75  GSList *l;
76  struct srd_decoder *dec;
77 
78  for (l = pd_list; l; l = l->next) {
79  dec = l->data;
80  if (!strcmp(dec->id, id))
81  return dec;
82  }
83 
84  return NULL;
85 }
86 
87 static int get_probes(const struct srd_decoder *d, const char *attr,
88  GSList **pl)
89 {
90  PyObject *py_probelist, *py_entry;
91  struct srd_probe *p;
92  int ret, num_probes, i;
93 
94  if (!PyObject_HasAttrString(d->py_dec, attr))
95  /* No probes of this type specified. */
96  return SRD_OK;
97 
98  ret = SRD_ERR_PYTHON;
99  py_probelist = py_entry = NULL;
100 
101  py_probelist = PyObject_GetAttrString(d->py_dec, attr);
102  if (!PyList_Check(py_probelist)) {
103  srd_err("Protocol decoder %s %s attribute is not "
104  "a list.", d->name, attr);
105  goto err_out;
106  }
107 
108  num_probes = PyList_Size(py_probelist);
109  if (num_probes == 0)
110  /* Empty probelist. */
111  return SRD_OK;
112 
113  for (i = 0; i < num_probes; i++) {
114  py_entry = PyList_GetItem(py_probelist, i);
115  if (!PyDict_Check(py_entry)) {
116  srd_err("Protocol decoder %s %s attribute is not "
117  "a list with dict elements.", d->name, attr);
118  goto err_out;
119  }
120 
121  if (!(p = g_try_malloc(sizeof(struct srd_probe)))) {
122  srd_err("Failed to g_malloc() struct srd_probe.");
123  ret = SRD_ERR_MALLOC;
124  goto err_out;
125  }
126 
127  if ((py_dictitem_as_str(py_entry, "id", &p->id)) != SRD_OK)
128  goto err_out;
129  if ((py_dictitem_as_str(py_entry, "name", &p->name)) != SRD_OK)
130  goto err_out;
131  if ((py_dictitem_as_str(py_entry, "desc", &p->desc)) != SRD_OK)
132  goto err_out;
133  p->order = i;
134 
135  *pl = g_slist_append(*pl, p);
136  }
137  ret = SRD_OK;
138 
139 err_out:
140  Py_DecRef(py_entry);
141  Py_DecRef(py_probelist);
142 
143  return ret;
144 }
145 
146 static int get_options(struct srd_decoder *d)
147 {
148  PyObject *py_opts, *py_keys, *py_values, *py_val, *py_desc, *py_default;
149  Py_ssize_t i;
150  struct srd_decoder_option *o;
151  gint64 def_long;
152  int num_keys, overflow, ret;
153  char *key, *def_str;
154 
155  ret = SRD_ERR_PYTHON;
156  key = NULL;
157 
158  if (!PyObject_HasAttrString(d->py_dec, "options"))
159  /* That's fine. */
160  return SRD_OK;
161 
162  /* If present, options must be a dictionary. */
163  py_opts = PyObject_GetAttrString(d->py_dec, "options");
164  if (!PyDict_Check(py_opts)) {
165  srd_err("Protocol decoder %s options attribute is not "
166  "a dictionary.", d->name);
167  goto err_out;
168  }
169 
170  py_keys = PyDict_Keys(py_opts);
171  py_values = PyDict_Values(py_opts);
172  num_keys = PyList_Size(py_keys);
173  for (i = 0; i < num_keys; i++) {
174  py_str_as_str(PyList_GetItem(py_keys, i), &key);
175  srd_dbg("option '%s'", key);
176  py_val = PyList_GetItem(py_values, i);
177  if (!PyList_Check(py_val) || PyList_Size(py_val) != 2) {
178  srd_err("Protocol decoder %s option '%s' value must be "
179  "a list with two elements.", d->name, key);
180  goto err_out;
181  }
182  py_desc = PyList_GetItem(py_val, 0);
183  if (!PyUnicode_Check(py_desc)) {
184  srd_err("Protocol decoder %s option '%s' has no "
185  "description.", d->name, key);
186  goto err_out;
187  }
188  py_default = PyList_GetItem(py_val, 1);
189  if (!PyUnicode_Check(py_default) && !PyLong_Check(py_default)) {
190  srd_err("Protocol decoder %s option '%s' has default "
191  "of unsupported type '%s'.", d->name, key,
192  Py_TYPE(py_default)->tp_name);
193  goto err_out;
194  }
195  if (!(o = g_try_malloc(sizeof(struct srd_decoder_option)))) {
196  srd_err("option malloc failed");
197  goto err_out;
198  }
199  o->id = g_strdup(key);
200  py_str_as_str(py_desc, &o->desc);
201  if (PyUnicode_Check(py_default)) {
202  /* UTF-8 string */
203  py_str_as_str(py_default, &def_str);
204  o->def = g_variant_new_string(def_str);
205  g_free(def_str);
206  } else {
207  /* Long */
208  def_long = PyLong_AsLongAndOverflow(py_default, &overflow);
209  if (overflow) {
210  /* Value is < LONG_MIN or > LONG_MAX */
211  PyErr_Clear();
212  srd_err("Protocol decoder %s option '%s' has "
213  "invalid default value.", d->name, key);
214  goto err_out;
215  }
216  o->def = g_variant_new_int64(def_long);
217  }
218  g_variant_ref_sink(o->def);
219  d->options = g_slist_append(d->options, o);
220  }
221  Py_DecRef(py_keys);
222  Py_DecRef(py_values);
223 
224  ret = SRD_OK;
225 
226 err_out:
227  Py_XDECREF(py_opts);
228  g_free(key);
229 
230  return ret;
231 }
232 
233 /**
234  * Load a protocol decoder module into the embedded Python interpreter.
235  *
236  * @param module_name The module name to be loaded.
237  *
238  * @return SRD_OK upon success, a (negative) error code otherwise.
239  *
240  * @since 0.1.0
241  */
242 SRD_API int srd_decoder_load(const char *module_name)
243 {
244  PyObject *py_basedec, *py_method, *py_attr, *py_annlist, *py_ann;
245  struct srd_decoder *d;
246  int alen, ret, i;
247  char **ann;
248  struct srd_probe *p;
249  GSList *l;
250 
251  srd_dbg("Loading protocol decoder '%s'.", module_name);
252 
253  py_basedec = py_method = py_attr = NULL;
254 
255  if (!(d = g_try_malloc0(sizeof(struct srd_decoder)))) {
256  srd_dbg("Failed to g_malloc() struct srd_decoder.");
257  ret = SRD_ERR_MALLOC;
258  goto err_out;
259  }
260 
261  ret = SRD_ERR_PYTHON;
262 
263  /* Import the Python module. */
264  if (!(d->py_mod = PyImport_ImportModule(module_name))) {
265  srd_exception_catch("Import of '%s' failed.", module_name);
266  goto err_out;
267  }
268 
269  /* Get the 'Decoder' class as Python object. */
270  if (!(d->py_dec = PyObject_GetAttrString(d->py_mod, "Decoder"))) {
271  /* This generated an AttributeError exception. */
272  PyErr_Clear();
273  srd_err("Decoder class not found in protocol decoder %s.",
274  module_name);
275  goto err_out;
276  }
277 
278  if (!(py_basedec = PyObject_GetAttrString(mod_sigrokdecode, "Decoder"))) {
279  srd_dbg("sigrokdecode module not loaded.");
280  goto err_out;
281  }
282 
283  if (!PyObject_IsSubclass(d->py_dec, py_basedec)) {
284  srd_err("Decoder class in protocol decoder module %s is not "
285  "a subclass of sigrokdecode.Decoder.", module_name);
286  goto err_out;
287  }
288  Py_CLEAR(py_basedec);
289 
290  /* Check for a proper start() method. */
291  if (!PyObject_HasAttrString(d->py_dec, "start")) {
292  srd_err("Protocol decoder %s has no start() method Decoder "
293  "class.", module_name);
294  goto err_out;
295  }
296  py_method = PyObject_GetAttrString(d->py_dec, "start");
297  if (!PyFunction_Check(py_method)) {
298  srd_err("Protocol decoder %s Decoder class attribute 'start' "
299  "is not a method.", module_name);
300  goto err_out;
301  }
302  Py_CLEAR(py_method);
303 
304  /* Check for a proper decode() method. */
305  if (!PyObject_HasAttrString(d->py_dec, "decode")) {
306  srd_err("Protocol decoder %s has no decode() method Decoder "
307  "class.", module_name);
308  goto err_out;
309  }
310  py_method = PyObject_GetAttrString(d->py_dec, "decode");
311  if (!PyFunction_Check(py_method)) {
312  srd_err("Protocol decoder %s Decoder class attribute 'decode' "
313  "is not a method.", module_name);
314  goto err_out;
315  }
316  Py_CLEAR(py_method);
317 
318  if (get_options(d) != SRD_OK)
319  goto err_out;
320 
321  /* Check and import required probes. */
322  if (get_probes(d, "probes", &d->probes) != SRD_OK)
323  goto err_out;
324 
325  /* Check and import optional probes. */
326  if (get_probes(d, "optional_probes", &d->opt_probes) != SRD_OK)
327  goto err_out;
328 
329  /*
330  * Fix order numbers for the optional probes.
331  *
332  * Example:
333  * Required probes: r1, r2, r3. Optional: o1, o2, o3, o4.
334  * 'order' fields in the d->probes list = 0, 1, 2.
335  * 'order' fields in the d->opt_probes list = 3, 4, 5, 6.
336  */
337  for (l = d->opt_probes; l; l = l->next) {
338  p = l->data;
339  p->order += g_slist_length(d->probes);
340  }
341 
342  /* Store required fields in newly allocated strings. */
343  if (py_attr_as_str(d->py_dec, "id", &(d->id)) != SRD_OK)
344  goto err_out;
345 
346  if (py_attr_as_str(d->py_dec, "name", &(d->name)) != SRD_OK)
347  goto err_out;
348 
349  if (py_attr_as_str(d->py_dec, "longname", &(d->longname)) != SRD_OK)
350  goto err_out;
351 
352  if (py_attr_as_str(d->py_dec, "desc", &(d->desc)) != SRD_OK)
353  goto err_out;
354 
355  if (py_attr_as_str(d->py_dec, "license", &(d->license)) != SRD_OK)
356  goto err_out;
357 
358  /* Convert class annotation attribute to GSList of **char. */
359  d->annotations = NULL;
360  if (PyObject_HasAttrString(d->py_dec, "annotations")) {
361  py_annlist = PyObject_GetAttrString(d->py_dec, "annotations");
362  if (!PyList_Check(py_annlist)) {
363  srd_err("Protocol decoder module %s annotations "
364  "should be a list.", module_name);
365  goto err_out;
366  }
367  alen = PyList_Size(py_annlist);
368  for (i = 0; i < alen; i++) {
369  py_ann = PyList_GetItem(py_annlist, i);
370  if (!PyList_Check(py_ann) || PyList_Size(py_ann) != 2) {
371  srd_err("Protocol decoder module %s "
372  "annotation %d should be a list with "
373  "two elements.", module_name, i + 1);
374  goto err_out;
375  }
376 
377  if (py_strlist_to_char(py_ann, &ann) != SRD_OK) {
378  goto err_out;
379  }
380  d->annotations = g_slist_append(d->annotations, ann);
381  }
382  }
383 
384  /* Append it to the list of supported/loaded decoders. */
385  pd_list = g_slist_append(pd_list, d);
386 
387  ret = SRD_OK;
388 
389 err_out:
390  if (ret != SRD_OK) {
391  Py_XDECREF(py_method);
392  Py_XDECREF(py_basedec);
393  Py_XDECREF(d->py_dec);
394  Py_XDECREF(d->py_mod);
395  g_free(d);
396  }
397 
398  return ret;
399 }
400 
401 /**
402  * Return a protocol decoder's docstring.
403  *
404  * @param dec The loaded protocol decoder.
405  *
406  * @return A newly allocated buffer containing the protocol decoder's
407  * documentation. The caller is responsible for free'ing the buffer.
408  *
409  * @since 0.1.0
410  */
411 SRD_API char *srd_decoder_doc_get(const struct srd_decoder *dec)
412 {
413  PyObject *py_str;
414  char *doc;
415 
416  if (!PyObject_HasAttrString(dec->py_mod, "__doc__"))
417  return NULL;
418 
419  if (!(py_str = PyObject_GetAttrString(dec->py_mod, "__doc__"))) {
420  srd_exception_catch("");
421  return NULL;
422  }
423 
424  doc = NULL;
425  if (py_str != Py_None)
426  py_str_as_str(py_str, &doc);
427  Py_DecRef(py_str);
428 
429  return doc;
430 }
431 
432 static void free_probes(GSList *probelist)
433 {
434  GSList *l;
435  struct srd_probe *p;
436 
437  if (probelist == NULL)
438  return;
439 
440  for (l = probelist; l; l = l->next) {
441  p = l->data;
442  g_free(p->id);
443  g_free(p->name);
444  g_free(p->desc);
445  g_free(p);
446  }
447  g_slist_free(probelist);
448 }
449 
450 /**
451  * Unload the specified protocol decoder.
452  *
453  * @param dec The struct srd_decoder to be unloaded.
454  *
455  * @return SRD_OK upon success, a (negative) error code otherwise.
456  *
457  * @since 0.1.0
458  */
460 {
461  struct srd_decoder_option *o;
462  GSList *l;
463 
464  srd_dbg("Unloading protocol decoder '%s'.", dec->name);
465 
466  /*
467  * Since any instances of this decoder need to be released as well,
468  * but they could be anywhere in the stack, just free the entire
469  * stack. A frontend reloading a decoder thus has to restart all
470  * instances, and rebuild the stack.
471  */
472  srd_inst_free_all(NULL);
473 
474  for (l = dec->options; l; l = l->next) {
475  o = l->data;
476  g_free(o->id);
477  g_free(o->desc);
478  g_variant_unref(o->def);
479  g_free(o);
480  }
481  g_slist_free(dec->options);
482 
483  free_probes(dec->probes);
484  free_probes(dec->opt_probes);
485  g_free(dec->id);
486  g_free(dec->name);
487  g_free(dec->longname);
488  g_free(dec->desc);
489  g_free(dec->license);
490 
491  /* The module's Decoder class. */
492  Py_XDECREF(dec->py_dec);
493  /* The module itself. */
494  Py_XDECREF(dec->py_mod);
495 
496  /* TODO: (g_)free dec itself? */
497 
498  return SRD_OK;
499 }
500 
501 /**
502  * Load all installed protocol decoders.
503  *
504  * @return SRD_OK upon success, a (negative) error code otherwise.
505  *
506  * @since 0.1.0
507  */
509 {
510  GDir *dir;
511  GError *error;
512  const gchar *direntry;
513 
514  if (!(dir = g_dir_open(DECODERS_DIR, 0, &error))) {
515  srd_err("Unable to open %s for reading.", DECODERS_DIR);
516  return SRD_ERR_DECODERS_DIR;
517  }
518 
519  while ((direntry = g_dir_read_name(dir)) != NULL) {
520  /* The directory name is the module name (e.g. "i2c"). */
521  srd_decoder_load(direntry);
522  }
523  g_dir_close(dir);
524 
525  return SRD_OK;
526 }
527 
528 /**
529  * Unload all loaded protocol decoders.
530  *
531  * @return SRD_OK upon success, a (negative) error code otherwise.
532  *
533  * @since 0.1.0
534  */
536 {
537  GSList *l;
538  struct srd_decoder *dec;
539 
540  for (l = pd_list; l; l = l->next) {
541  dec = l->data;
542  srd_decoder_unload(dec);
543  }
544 
545  return SRD_OK;
546 }
547 
548 /** @} */