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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 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <sigrokdecode.h> /* First, so we avoid a _POSIX_C_SOURCE warning. */
22#include <stdio.h>
23#include <string.h>
24#include <dirent.h>
25#include <config.h>
26
27/* Re-define some string functions for Python >= 3.0. */
28#if PY_VERSION_HEX >= 0x03000000
29#define PyString_AsString PyBytes_AsString
30#define PyString_FromString PyBytes_FromString
31#define PyString_Check PyBytes_Check
32#endif
33
34/* The list of protocol decoders. */
35GSList *list_pds = NULL;
36
37/*
38 * Here's a quick overview of Python/C API reference counting.
39 *
40 * Check the Python/C API docs for what type of reference a function returns.
41 *
42 * - If it returns a "new reference", you're responsible to Py_XDECREF() it.
43 *
44 * - If it returns a "borrowed reference", you MUST NOT Py_XDECREF() it.
45 *
46 * - If a function "steals" a reference, you no longer are responsible for
47 * Py_XDECREF()ing it (someone else will do it for you at some point).
48 */
49
50static int srd_load_decoder(const char *name, struct srd_decoder **dec);
51
52/**
53 * Initialize libsigrokdecode.
54 *
55 * @return SRD_OK upon success, a (negative) error code otherwise.
56 */
57int srd_init(void)
58{
59 DIR *dir;
60 struct dirent *dp;
61 char *decodername;
62 struct srd_decoder *dec;
63 int ret;
64
65 /* Py_Initialize() returns void and usually cannot fail. */
66 Py_Initialize();
67
68 /* Add search directory for the protocol decoders. */
69 /* FIXME: Check error code. */
70 /* FIXME: What happens if this function is called multiple times? */
71 PyRun_SimpleString("import sys;"
72 "sys.path.append(r'" DECODERS_DIR "');");
73
74 if (!(dir = opendir(DECODERS_DIR)))
75 return SRD_ERR_DECODERS_DIR;
76
77 while ((dp = readdir(dir)) != NULL) {
78 if (!g_str_has_suffix(dp->d_name, ".py"))
79 continue;
80
81 /* Decoder name == filename (without .py suffix). */
82 decodername = g_strndup(dp->d_name, strlen(dp->d_name) - 3);
83
84 /* TODO: Error handling. */
85 dec = malloc(sizeof(struct srd_decoder));
86
87 /* Load the decoder. */
88 ret = srd_load_decoder(decodername, &dec);
89
90 /* Append it to the list of supported/loaded decoders. */
91 list_pds = g_slist_append(list_pds, dec);
92 }
93 closedir(dir);
94
95 return SRD_OK;
96}
97
98/**
99 * Returns the list of supported/loaded protocol decoders.
100 *
101 * This is a GSList containing the names of the decoders as strings.
102 *
103 * @return List of decoders, NULL if none are supported or loaded.
104 */
105GSList *srd_list_decoders(void)
106{
107 return list_pds;
108}
109
110/**
111 * Get the decoder with the specified ID.
112 *
113 * @param id The ID string of the decoder to return.
114 * @return The decoder with the specified ID, or NULL if not found.
115 */
116struct srd_decoder *srd_get_decoder_by_id(const char *id)
117{
118 GSList *l;
119 struct srd_decoder *dec;
120
121 for (l = srd_list_decoders(); l; l = l->next) {
122 dec = l->data;
123 if (!strcmp(dec->id, id))
124 return dec;
125 }
126
127 return NULL;
128}
129
130/**
131 * Helper function to handle Python strings.
132 *
133 * TODO: @param entries.
134 *
135 * @return SRD_OK upon success, a (negative) error code otherwise.
136 * The 'outstr' argument points to a malloc()ed string upon success.
137 */
138static int h_str(PyObject *py_res, PyObject *py_func, PyObject *py_mod,
139 const char *key, char **outstr)
140{
141 PyObject *py_str;
142 char *str;
143 int ret;
144
145 py_str = PyMapping_GetItemString(py_res, (char *)key);
146 if (!py_str || !PyString_Check(py_str)) {
147 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
148 goto err_h_decref_func;
149 }
150
151 /*
152 * PyString_AsString()'s returned string refers to an internal buffer
153 * (not a copy), i.e. the data must not be modified, and the memory
154 * must not be free()'d.
155 */
156 if (!(str = PyString_AsString(py_str))) {
157 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
158 goto err_h_decref_str;
159 }
160
161 if (!(*outstr = g_strdup(str))) {
162 ret = SRD_ERR_MALLOC;
163 goto err_h_decref_str;
164 }
165
166 Py_XDECREF(py_str);
167
168 return SRD_OK;
169
170err_h_decref_str:
171 Py_XDECREF(py_str);
172err_h_decref_func:
173 Py_XDECREF(py_func);
174 Py_XDECREF(py_mod);
175
176 if (PyErr_Occurred())
177 PyErr_Print(); /* Returns void. */
178
179 return ret;
180}
181
182/**
183 * TODO
184 *
185 * @param name TODO
186 *
187 * @return SRD_OK upon success, a (negative) error code otherwise.
188 */
189static int srd_load_decoder(const char *name,
190 struct srd_decoder **dec)
191{
192 struct srd_decoder *d;
193 PyObject *py_mod, *py_func, *py_res /* , *py_tuple */;
194 int r;
195
196 /* "Import" the Python module. */
197 if (!(py_mod = PyImport_ImportModule(name))) { /* NEWREF */
198 PyErr_Print(); /* Returns void. */
199 return SRD_ERR_PYTHON; /* TODO: More specific error? */
200 }
201
202 /* Get the 'register' function name as Python callable object. */
203 py_func = PyObject_GetAttrString(py_mod, "register"); /* NEWREF */
204 if (!py_func || !PyCallable_Check(py_func)) {
205 if (PyErr_Occurred())
206 PyErr_Print(); /* Returns void. */
207 Py_XDECREF(py_mod);
208 return SRD_ERR_PYTHON; /* TODO: More specific error? */
209 }
210
211 /* Call the 'register' function without arguments, get the result. */
212 if (!(py_res = PyObject_CallFunction(py_func, NULL))) { /* NEWREF */
213 PyErr_Print(); /* Returns void. */
214 Py_XDECREF(py_func);
215 Py_XDECREF(py_mod);
216 return SRD_ERR_PYTHON; /* TODO: More specific error? */
217 }
218
219 if (!(d = malloc(sizeof(struct srd_decoder))))
220 return SRD_ERR_MALLOC;
221
222 if ((r = h_str(py_res, py_func, py_mod, "id", &(d->id))) < 0)
223 return r;
224
225 if ((r = h_str(py_res, py_func, py_mod, "name", &(d->name))) < 0)
226 return r;
227
228 if ((r = h_str(py_res, py_func, py_mod, "desc", &(d->desc))) < 0)
229 return r;
230
231 d->py_mod = py_mod;
232
233 Py_XDECREF(py_res);
234 Py_XDECREF(py_func);
235
236 /* Get the 'decode' function name as Python callable object. */
237 py_func = PyObject_GetAttrString(py_mod, "decode"); /* NEWREF */
238 if (!py_func || !PyCallable_Check(py_func)) {
239 if (PyErr_Occurred())
240 PyErr_Print(); /* Returns void. */
241 Py_XDECREF(py_mod);
242 return SRD_ERR_PYTHON; /* TODO: More specific error? */
243 }
244
245 d->py_func = py_func;
246
247 /* TODO: Handle func, inputformats, outputformats. */
248 /* Note: They must at least be set to NULL, will segfault otherwise. */
249 d->func = NULL;
250 d->inputformats = NULL;
251 d->outputformats = NULL;
252
253 *dec = d;
254
255 return SRD_OK;
256}
257
258/**
259 * Run the specified decoder function.
260 *
261 * @param dec TODO
262 * @param inbuf TODO
263 * @param inbuflen TODO
264 * @param outbuf TODO
265 * @param outbuflen TODO
266 *
267 * @return SRD_OK upon success, a (negative) error code otherwise.
268 */
269int srd_run_decoder(struct srd_decoder *dec,
270 uint8_t *inbuf, uint64_t inbuflen,
271 uint8_t **outbuf, uint64_t *outbuflen)
272{
273 PyObject *py_mod, *py_func, *py_args, *py_value, *py_res;
274 int r, ret;
275
276 /* TODO: Use #defines for the return codes. */
277
278 /* Return an error upon unusable input. */
279 if (dec == NULL)
280 return SRD_ERR_ARGS; /* TODO: More specific error? */
281 if (inbuf == NULL)
282 return SRD_ERR_ARGS; /* TODO: More specific error? */
283 if (inbuflen == 0) /* No point in working on empty buffers. */
284 return SRD_ERR_ARGS; /* TODO: More specific error? */
285 if (outbuf == NULL)
286 return SRD_ERR_ARGS; /* TODO: More specific error? */
287 if (outbuflen == NULL)
288 return SRD_ERR_ARGS; /* TODO: More specific error? */
289
290 /* TODO: Error handling. */
291 py_mod = dec->py_mod;
292 Py_XINCREF(py_mod);
293 py_func = dec->py_func;
294 Py_XINCREF(py_func);
295
296 /* Create a Python tuple of size 1. */
297 if (!(py_args = PyTuple_New(1))) { /* NEWREF */
298 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
299 goto err_run_decref_func;
300 }
301
302 /* Get the input buffer as Python "string" (byte array). */
303 /* TODO: int vs. uint64_t for 'inbuflen'? */
304 if (!(py_value = Py_BuildValue("s#", inbuf, inbuflen))) { /* NEWREF */
305 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
306 goto err_run_decref_args;
307 }
308
309 /*
310 * IMPORTANT: PyTuple_SetItem() "steals" a reference to py_value!
311 * That means we are no longer responsible for Py_XDECREF()'ing it.
312 * It will automatically be free'd when the 'py_args' tuple is free'd.
313 */
314 if (PyTuple_SetItem(py_args, 0, py_value) != 0) { /* STEAL */
315 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
316 Py_XDECREF(py_value); /* TODO: Ref. stolen upon error? */
317 goto err_run_decref_args;
318 }
319
320 if (!(py_res = PyObject_CallObject(py_func, py_args))) { /* NEWREF */
321 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
322 goto err_run_decref_args;
323 }
324
325 if ((r = PyObject_AsCharBuffer(py_res, (const char **)outbuf,
326 (Py_ssize_t *)outbuflen))) {
327 ret = SRD_ERR_PYTHON; /* TODO: More specific error? */
328 Py_XDECREF(py_res);
329 goto err_run_decref_args;
330 }
331
332 ret = SRD_OK;
333
334 Py_XDECREF(py_res);
335
336err_run_decref_args:
337 Py_XDECREF(py_args);
338err_run_decref_func:
339 Py_XDECREF(py_func);
340 Py_XDECREF(py_mod);
341
342 if (PyErr_Occurred())
343 PyErr_Print(); /* Returns void. */
344
345 return ret;
346}
347
348/**
349 * TODO
350 */
351static int srd_unload_decoder(struct srd_decoder *dec)
352{
353 g_free(dec->id);
354 g_free(dec->name);
355 g_free(dec->desc);
356 g_free(dec->func);
357
358 /* TODO: Free everything in inputformats and outputformats. */
359
360 if (dec->inputformats != NULL)
361 g_slist_free(dec->inputformats);
362 if (dec->outputformats != NULL)
363 g_slist_free(dec->outputformats);
364
365 Py_XDECREF(dec->py_func);
366 Py_XDECREF(dec->py_mod);
367
368 return SRD_OK;
369}
370
371/**
372 * TODO
373 */
374static int srd_unload_all_decoders(void)
375{
376 GSList *l;
377 struct srd_decoder *dec;
378
379 for (l = srd_list_decoders(); l; l = l->next) {
380 dec = l->data;
381 /* TODO: Error handling. */
382 srd_unload_decoder(dec);
383 }
384
385 return SRD_OK;
386}
387
388/**
389 * Shutdown libsigrokdecode.
390 *
391 * @return SRD_OK upon success, a (negative) error code otherwise.
392 */
393int srd_exit(void)
394{
395 /* Unload/free all decoders, and then the list of decoders itself. */
396 /* TODO: Error handling. */
397 srd_unload_all_decoders();
398 g_slist_free(list_pds);
399
400 /* Py_Finalize() returns void, any finalization errors are ignored. */
401 Py_Finalize();
402
403 return SRD_OK;
404}