libsigrokdecode
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decoder.c
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1 /*
2  * This file is part of the sigrok 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 "sigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
23 #include "sigrokdecode-internal.h"
24 #include <glib.h>
25 
26 /* The list of protocol decoders. */
27 SRD_PRIV GSList *pd_list = NULL;
28 
29 /* module_sigrokdecode.c */
30 extern SRD_PRIV PyObject *mod_sigrokdecode;
31 
32 /**
33  * Returns the list of supported/loaded protocol decoders.
34  *
35  * This is a GSList containing the names of the decoders as strings.
36  *
37  * @return List of decoders, NULL if none are supported or loaded.
38  */
40 {
41  return pd_list;
42 }
43 
44 /**
45  * Get the decoder with the specified ID.
46  *
47  * @param id The ID string of the decoder to return.
48  *
49  * @return The decoder with the specified ID, or NULL if not found.
50  */
51 SRD_API struct srd_decoder *srd_decoder_get_by_id(const char *id)
52 {
53  GSList *l;
54  struct srd_decoder *dec;
55 
56  for (l = srd_decoder_list(); l; l = l->next) {
57  dec = l->data;
58  if (!strcmp(dec->id, id))
59  return dec;
60  }
61 
62  return NULL;
63 }
64 
65 static int get_probes(const struct srd_decoder *d, const char *attr,
66  GSList **pl)
67 {
68  PyObject *py_probelist, *py_entry;
69  struct srd_probe *p;
70  int ret, num_probes, i;
71 
72  if (!PyObject_HasAttrString(d->py_dec, attr))
73  /* No probes of this type specified. */
74  return SRD_OK;
75 
76  ret = SRD_ERR_PYTHON;
77  py_probelist = py_entry = NULL;
78 
79  py_probelist = PyObject_GetAttrString(d->py_dec, attr);
80  if (!PyList_Check(py_probelist)) {
81  srd_err("Protocol decoder %s %s attribute is not "
82  "a list.", d->name, attr);
83  goto err_out;
84  }
85 
86  num_probes = PyList_Size(py_probelist);
87  if (num_probes == 0)
88  /* Empty probelist. */
89  return SRD_OK;
90 
91  for (i = 0; i < num_probes; i++) {
92  py_entry = PyList_GetItem(py_probelist, i);
93  if (!PyDict_Check(py_entry)) {
94  srd_err("Protocol decoder %s %s attribute is not "
95  "a list with dict elements.", d->name, attr);
96  goto err_out;
97  }
98 
99  if (!(p = g_try_malloc(sizeof(struct srd_probe)))) {
100  srd_err("Failed to g_malloc() struct srd_probe.");
101  ret = SRD_ERR_MALLOC;
102  goto err_out;
103  }
104 
105  if ((py_dictitem_as_str(py_entry, "id", &p->id)) != SRD_OK)
106  goto err_out;
107  if ((py_dictitem_as_str(py_entry, "name", &p->name)) != SRD_OK)
108  goto err_out;
109  if ((py_dictitem_as_str(py_entry, "desc", &p->desc)) != SRD_OK)
110  goto err_out;
111  p->order = i;
112 
113  *pl = g_slist_append(*pl, p);
114  }
115  ret = SRD_OK;
116 
117 err_out:
118  Py_DecRef(py_entry);
119  Py_DecRef(py_probelist);
120 
121  return ret;
122 }
123 
124 /**
125  * Load a protocol decoder module into the embedded Python interpreter.
126  *
127  * @param name The module name to be loaded.
128  *
129  * @return SRD_OK upon success, a (negative) error code otherwise.
130  */
131 SRD_API int srd_decoder_load(const char *module_name)
132 {
133  PyObject *py_basedec, *py_method, *py_attr, *py_annlist, *py_ann;
134  struct srd_decoder *d;
135  int alen, ret, i;
136  char **ann;
137 
138  srd_dbg("Loading protocol decoder '%s'.", module_name);
139 
140  py_basedec = py_method = py_attr = NULL;
141 
142  if (!(d = g_try_malloc0(sizeof(struct srd_decoder)))) {
143  srd_dbg("Failed to g_malloc() struct srd_decoder.");
144  ret = SRD_ERR_MALLOC;
145  goto err_out;
146  }
147 
148  ret = SRD_ERR_PYTHON;
149 
150  /* Import the Python module. */
151  if (!(d->py_mod = PyImport_ImportModule(module_name))) {
152  srd_exception_catch("Import of '%s' failed.", module_name);
153  goto err_out;
154  }
155 
156  /* Get the 'Decoder' class as Python object. */
157  if (!(d->py_dec = PyObject_GetAttrString(d->py_mod, "Decoder"))) {
158  /* This generated an AttributeError exception. */
159  PyErr_Clear();
160  srd_err("Decoder class not found in protocol decoder %s.",
161  module_name);
162  goto err_out;
163  }
164 
165  if (!(py_basedec = PyObject_GetAttrString(mod_sigrokdecode, "Decoder"))) {
166  srd_dbg("sigrokdecode module not loaded.");
167  goto err_out;
168  }
169 
170  if (!PyObject_IsSubclass(d->py_dec, py_basedec)) {
171  srd_err("Decoder class in protocol decoder module %s is not "
172  "a subclass of sigrokdecode.Decoder.", module_name);
173  goto err_out;
174  }
175  Py_CLEAR(py_basedec);
176 
177  /* Check for a proper start() method. */
178  if (!PyObject_HasAttrString(d->py_dec, "start")) {
179  srd_err("Protocol decoder %s has no start() method Decoder "
180  "class.", module_name);
181  goto err_out;
182  }
183  py_method = PyObject_GetAttrString(d->py_dec, "start");
184  if (!PyFunction_Check(py_method)) {
185  srd_err("Protocol decoder %s Decoder class attribute 'start' "
186  "is not a method.", module_name);
187  goto err_out;
188  }
189  Py_CLEAR(py_method);
190 
191  /* Check for a proper decode() method. */
192  if (!PyObject_HasAttrString(d->py_dec, "decode")) {
193  srd_err("Protocol decoder %s has no decode() method Decoder "
194  "class.", module_name);
195  goto err_out;
196  }
197  py_method = PyObject_GetAttrString(d->py_dec, "decode");
198  if (!PyFunction_Check(py_method)) {
199  srd_err("Protocol decoder %s Decoder class attribute 'decode' "
200  "is not a method.", module_name);
201  goto err_out;
202  }
203  Py_CLEAR(py_method);
204 
205  /* If present, options must be a dictionary. */
206  if (PyObject_HasAttrString(d->py_dec, "options")) {
207  py_attr = PyObject_GetAttrString(d->py_dec, "options");
208  if (!PyDict_Check(py_attr)) {
209  srd_err("Protocol decoder %s options attribute is not "
210  "a dictionary.", d->name);
211  Py_DecRef(py_attr);
212  goto err_out;
213  }
214  Py_DecRef(py_attr);
215  }
216 
217  /* Check and import required probes. */
218  if (get_probes(d, "probes", &d->probes) != SRD_OK)
219  goto err_out;
220 
221  /* Check and import optional probes. */
222  if (get_probes(d, "optional_probes", &d->opt_probes) != SRD_OK)
223  goto err_out;
224 
225  /* Store required fields in newly allocated strings. */
226  if (py_attr_as_str(d->py_dec, "id", &(d->id)) != SRD_OK)
227  goto err_out;
228 
229  if (py_attr_as_str(d->py_dec, "name", &(d->name)) != SRD_OK)
230  goto err_out;
231 
232  if (py_attr_as_str(d->py_dec, "longname", &(d->longname)) != SRD_OK)
233  goto err_out;
234 
235  if (py_attr_as_str(d->py_dec, "desc", &(d->desc)) != SRD_OK)
236  goto err_out;
237 
238  if (py_attr_as_str(d->py_dec, "license", &(d->license)) != SRD_OK)
239  goto err_out;
240 
241  /* Convert class annotation attribute to GSList of **char. */
242  d->annotations = NULL;
243  if (PyObject_HasAttrString(d->py_dec, "annotations")) {
244  py_annlist = PyObject_GetAttrString(d->py_dec, "annotations");
245  if (!PyList_Check(py_annlist)) {
246  srd_err("Protocol decoder module %s annotations "
247  "should be a list.", module_name);
248  goto err_out;
249  }
250  alen = PyList_Size(py_annlist);
251  for (i = 0; i < alen; i++) {
252  py_ann = PyList_GetItem(py_annlist, i);
253  if (!PyList_Check(py_ann) || PyList_Size(py_ann) != 2) {
254  srd_err("Protocol decoder module %s "
255  "annotation %d should be a list with "
256  "two elements.", module_name, i + 1);
257  goto err_out;
258  }
259 
260  if (py_strlist_to_char(py_ann, &ann) != SRD_OK) {
261  goto err_out;
262  }
263  d->annotations = g_slist_append(d->annotations, ann);
264  }
265  }
266 
267  /* Append it to the list of supported/loaded decoders. */
268  pd_list = g_slist_append(pd_list, d);
269 
270  ret = SRD_OK;
271 
272 err_out:
273  if (ret != SRD_OK) {
274  Py_XDECREF(py_method);
275  Py_XDECREF(py_basedec);
276  Py_XDECREF(d->py_dec);
277  Py_XDECREF(d->py_mod);
278  g_free(d);
279  }
280 
281  return ret;
282 }
283 
284 /**
285  * Return a protocol decoder's docstring.
286  *
287  * @param dec The loaded protocol decoder.
288  *
289  * @return A newly allocated buffer containing the protocol decoder's
290  * documentation. The caller is responsible for free'ing the buffer.
291  */
292 SRD_API char *srd_decoder_doc_get(const struct srd_decoder *dec)
293 {
294  PyObject *py_str;
295  char *doc;
296 
297  if (!PyObject_HasAttrString(dec->py_mod, "__doc__"))
298  return NULL;
299 
300  if (!(py_str = PyObject_GetAttrString(dec->py_mod, "__doc__"))) {
302  return NULL;
303  }
304 
305  doc = NULL;
306  if (py_str != Py_None)
307  py_str_as_str(py_str, &doc);
308  Py_DecRef(py_str);
309 
310  return doc;
311 }
312 
313 static void free_probes(GSList *probelist)
314 {
315  GSList *l;
316  struct srd_probe *p;
317 
318  if (probelist == NULL)
319  return;
320 
321  for (l = probelist; l; l = l->next) {
322  p = l->data;
323  g_free(p->id);
324  g_free(p->name);
325  g_free(p->desc);
326  g_free(p);
327  }
328  g_slist_free(probelist);
329 }
330 
331 /**
332  * Unload decoder module.
333  *
334  * @param dec The struct srd_decoder to be unloaded.
335  *
336  * @return SRD_OK upon success, a (negative) error code otherwise.
337  */
339 {
340  srd_dbg("Unloading protocol decoder '%s'.", dec->name);
341 
342  /*
343  * Since any instances of this decoder need to be released as well,
344  * but they could be anywhere in the stack, just free the entire
345  * stack. A frontend reloading a decoder thus has to restart all
346  * instances, and rebuild the stack.
347  */
348  srd_inst_free_all(NULL);
349 
350  free_probes(dec->probes);
351  free_probes(dec->opt_probes);
352  g_free(dec->id);
353  g_free(dec->name);
354  g_free(dec->longname);
355  g_free(dec->desc);
356  g_free(dec->license);
357 
358  /* The module's Decoder class. */
359  Py_XDECREF(dec->py_dec);
360  /* The module itself. */
361  Py_XDECREF(dec->py_mod);
362 
363  /* TODO: (g_)free dec itself? */
364 
365  return SRD_OK;
366 }
367 
368 /**
369  * Load all installed protocol decoders.
370  *
371  * @return SRD_OK upon success, a (negative) error code otherwise.
372  */
374 {
375  GDir *dir;
376  GError *error;
377  const gchar *direntry;
378 
379  if (!(dir = g_dir_open(DECODERS_DIR, 0, &error))) {
380  srd_err("Unable to open %s for reading.", DECODERS_DIR);
381  return SRD_ERR_DECODERS_DIR;
382  }
383 
384  while ((direntry = g_dir_read_name(dir)) != NULL) {
385  /* The directory name is the module name (e.g. "i2c"). */
386  srd_decoder_load(direntry);
387  }
388  g_dir_close(dir);
389 
390  return SRD_OK;
391 }
392 
393 /**
394  * Unload all loaded protocol decoders.
395  *
396  * @return SRD_OK upon success, a (negative) error code otherwise.
397  */
399 {
400  GSList *l;
401  struct srd_decoder *dec;
402 
403  for (l = srd_decoder_list(); l; l = l->next) {
404  dec = l->data;
405  srd_decoder_unload(dec);
406  }
407 
408  return SRD_OK;
409 }