libsigrokdecode  0.5.3
sigrok protocol decoding library
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Modules Pages
srd.c
Go to the documentation of this file.
1 /*
2  * This file is part of the libsigrokdecode project.
3  *
4  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
5  * Copyright (C) 2013 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-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
23 #include "libsigrokdecode.h"
24 #include <glib.h>
25 
26 /** @cond PRIVATE */
27 
28 /* Python module search paths */
29 SRD_PRIV GSList *searchpaths = NULL;
30 
31 /* session.c */
32 extern SRD_PRIV GSList *sessions;
33 extern SRD_PRIV int max_session_id;
34 
35 /** @endcond */
36 
37 /**
38  * @mainpage libsigrokdecode API
39  *
40  * @section sec_intro Introduction
41  *
42  * The <a href="http://sigrok.org">sigrok</a> project aims at creating a
43  * portable, cross-platform, Free/Libre/Open-Source signal analysis software
44  * suite that supports various device types (such as logic analyzers,
45  * oscilloscopes, multimeters, and more).
46  *
47  * <a href="http://sigrok.org/wiki/Libsigrokdecode">libsigrokdecode</a> is a
48  * shared library written in C which provides the basic API for (streaming)
49  * protocol decoding functionality.
50  *
51  * The <a href="http://sigrok.org/wiki/Protocol_decoders">protocol decoders</a>
52  * are written in Python (>= 3.0).
53  *
54  * @section sec_api API reference
55  *
56  * See the "Modules" page for an introduction to various libsigrokdecode
57  * related topics and the detailed API documentation of the respective
58  * functions.
59  *
60  * You can also browse the API documentation by file, or review all
61  * data structures.
62  *
63  * @section sec_mailinglists Mailing lists
64  *
65  * There is one mailing list for sigrok/libsigrokdecode: <a href="https://lists.sourceforge.net/lists/listinfo/sigrok-devel">sigrok-devel</a>.
66  *
67  * @section sec_irc IRC
68  *
69  * You can find the sigrok developers in the
70  * <a href="irc://chat.freenode.net/sigrok">\#sigrok</a>
71  * IRC channel on Freenode.
72  *
73  * @section sec_website Website
74  *
75  * <a href="http://sigrok.org/wiki/Libsigrokdecode">sigrok.org/wiki/Libsigrokdecode</a>
76  */
77 
78 /**
79  * @file
80  *
81  * Initializing and shutting down libsigrokdecode.
82  */
83 
84 /**
85  * @defgroup grp_init Initialization
86  *
87  * Initializing and shutting down libsigrokdecode.
88  *
89  * Before using any of the libsigrokdecode functionality, srd_init() must
90  * be called to initialize the library.
91  *
92  * When libsigrokdecode functionality is no longer needed, srd_exit() should
93  * be called.
94  *
95  * @{
96  */
97 
98 static int searchpath_add_xdg_dir(const char *datadir)
99 {
100  char *decdir;
101  int ret;
102 
103  decdir = g_build_filename(datadir, PACKAGE_TARNAME, "decoders", NULL);
104 
105  if (g_file_test(decdir, G_FILE_TEST_IS_DIR))
106  ret = srd_decoder_searchpath_add(decdir);
107  else
108  ret = SRD_OK; /* Just ignore non-existing directory. */
109 
110  g_free(decdir);
111 
112  return ret;
113 }
114 
115 static void print_versions(void)
116 {
117  GString *s;
118  GSList *l, *l_orig, *m;
119  char *str;
120  const char *lib, *version;
121 
122  srd_dbg("libsigrokdecode %s/%s (rt: %s/%s).",
125 
126  s = g_string_sized_new(200);
127  g_string_append(s, "Libs: ");
128  l_orig = srd_buildinfo_libs_get();
129  for (l = l_orig; l; l = l->next) {
130  m = l->data;
131  lib = m->data;
132  version = m->next->data;
133  g_string_append_printf(s, "%s %s, ", lib, version);
134  g_slist_free_full(m, g_free);
135  }
136  g_slist_free(l_orig);
137  s->str[s->len - 2] = '.';
138  s->str[s->len - 1] = '\0';
139  srd_dbg("%s", s->str);
140  g_string_free(s, TRUE);
141 
142  str = srd_buildinfo_host_get();
143  srd_dbg("Host: %s.", str);
144  g_free(str);
145 }
146 
147 static int print_searchpaths(void)
148 {
149  PyObject *py_paths, *py_path, *py_bytes;
150  PyGILState_STATE gstate;
151  GString *s;
152  GSList *l;
153  int i;
154 
155  s = g_string_sized_new(500);
156  g_string_append(s, "Protocol decoder search paths:\n");
157  for (l = searchpaths; l; l = l->next)
158  g_string_append_printf(s, " - %s\n", (const char *)l->data);
159  s->str[s->len - 1] = '\0';
160  srd_dbg("%s", s->str);
161  g_string_free(s, TRUE);
162 
163  gstate = PyGILState_Ensure();
164 
165  py_paths = PySys_GetObject("path");
166  if (!py_paths)
167  goto err;
168 
169  s = g_string_sized_new(500);
170  g_string_append(s, "Python system search paths:\n");
171  for (i = 0; i < PyList_Size(py_paths); i++) {
172  py_path = PyList_GetItem(py_paths, i);
173  py_bytes = PyUnicode_AsUTF8String(py_path);
174  g_string_append_printf(s, " - %s\n", PyBytes_AsString(py_bytes));
175  Py_DECREF(py_bytes);
176  }
177  s->str[s->len - 1] = '\0';
178  srd_dbg("%s", s->str);
179  g_string_free(s, TRUE);
180 
181  PyGILState_Release(gstate);
182 
183  return SRD_OK;
184 
185 err:
186  srd_err("Unable to query Python system search paths.");
187  PyGILState_Release(gstate);
188 
189  return SRD_ERR_PYTHON;
190 }
191 
192 /**
193  * Initialize libsigrokdecode.
194  *
195  * This initializes the Python interpreter, and creates and initializes
196  * a "sigrokdecode" Python module.
197  *
198  * Then, it searches for sigrok protocol decoders in the "decoders"
199  * subdirectory of the the libsigrokdecode installation directory.
200  * All decoders that are found are loaded into memory and added to an
201  * internal list of decoders, which can be queried via srd_decoder_list().
202  *
203  * The caller is responsible for calling the clean-up function srd_exit(),
204  * which will properly shut down libsigrokdecode and free its allocated memory.
205  *
206  * Multiple calls to srd_init(), without calling srd_exit() in between,
207  * are not allowed.
208  *
209  * @param path Path to an extra directory containing protocol decoders
210  * which will be added to the Python sys.path. May be NULL.
211  *
212  * @return SRD_OK upon success, a (negative) error code otherwise.
213  * Upon Python errors, SRD_ERR_PYTHON is returned. If the decoders
214  * directory cannot be accessed, SRD_ERR_DECODERS_DIR is returned.
215  * If not enough memory could be allocated, SRD_ERR_MALLOC is returned.
216  *
217  * @since 0.1.0
218  */
219 SRD_API int srd_init(const char *path)
220 {
221  const char *const *sys_datadirs;
222  const char *env_path;
223  size_t i;
224  int ret;
225 
226  if (max_session_id != -1) {
227  srd_err("libsigrokdecode is already initialized.");
228  return SRD_ERR;
229  }
230 
231  print_versions();
232 
233  srd_dbg("Initializing libsigrokdecode.");
234 
235  /* Add our own module to the list of built-in modules. */
236  PyImport_AppendInittab("sigrokdecode", PyInit_sigrokdecode);
237 
238  /* Initialize the Python interpreter. */
239  Py_InitializeEx(0);
240 
241  /* Locations relative to the XDG system data directories. */
242  sys_datadirs = g_get_system_data_dirs();
243  for (i = g_strv_length((char **)sys_datadirs); i > 0; i--) {
244  ret = searchpath_add_xdg_dir(sys_datadirs[i - 1]);
245  if (ret != SRD_OK) {
246  Py_Finalize();
247  return ret;
248  }
249  }
250 #ifdef DECODERS_DIR
251  /* Hardcoded decoders install location, if defined. */
252  if ((ret = srd_decoder_searchpath_add(DECODERS_DIR)) != SRD_OK) {
253  Py_Finalize();
254  return ret;
255  }
256 #endif
257  /* Location relative to the XDG user data directory. */
258  ret = searchpath_add_xdg_dir(g_get_user_data_dir());
259  if (ret != SRD_OK) {
260  Py_Finalize();
261  return ret;
262  }
263 
264  /* Path specified by the user. */
265  if (path) {
266  if ((ret = srd_decoder_searchpath_add(path)) != SRD_OK) {
267  Py_Finalize();
268  return ret;
269  }
270  }
271 
272  /* Environment variable overrides everything, for debugging. */
273  if ((env_path = g_getenv("SIGROKDECODE_DIR"))) {
274  if ((ret = srd_decoder_searchpath_add(env_path)) != SRD_OK) {
275  Py_Finalize();
276  return ret;
277  }
278  }
279 
280  /* Initialize the Python GIL (this also happens to acquire it). */
281  PyEval_InitThreads();
282 
283  /* Release the GIL (ignore return value, we don't need it here). */
284  (void)PyEval_SaveThread();
285 
286  max_session_id = 0;
287 
288  print_searchpaths();
289 
290  return SRD_OK;
291 }
292 
293 static void srd_session_destroy_cb(void *arg, void *ignored)
294 {
295  (void)ignored; // Prevent unused warning
296  srd_session_destroy((struct srd_session *)arg);
297 }
298 
299 /**
300  * Shutdown libsigrokdecode.
301  *
302  * This frees all the memory allocated for protocol decoders and shuts down
303  * the Python interpreter.
304  *
305  * This function should only be called if there was a (successful!) invocation
306  * of srd_init() before. Calling this function multiple times in a row, without
307  * any successful srd_init() calls in between, is not allowed.
308  *
309  * @return SRD_OK upon success, a (negative) error code otherwise.
310  *
311  * @since 0.1.0
312  */
313 SRD_API int srd_exit(void)
314 {
315  srd_dbg("Exiting libsigrokdecode.");
316 
317  g_slist_foreach(sessions, srd_session_destroy_cb, NULL);
318  g_slist_free(sessions);
319  sessions = NULL;
320 
322  g_slist_free_full(searchpaths, g_free);
323  searchpaths = NULL;
324 
325  /*
326  * Acquire the GIL, otherwise Py_Finalize() might have issues.
327  * Ignore the return value, we don't need it here.
328  */
329  if (Py_IsInitialized())
330  (void)PyGILState_Ensure();
331 
332  /* Py_Finalize() returns void, any finalization errors are ignored. */
333  Py_Finalize();
334 
335  /* Note: No need to release the GIL since Python is shut down now. */
336 
337  max_session_id = -1;
338 
339  return SRD_OK;
340 }
341 
342 /**
343  * Add an additional search directory for the protocol decoders.
344  *
345  * The specified directory is prepended (not appended!) to Python's sys.path,
346  * in order to search for sigrok protocol decoders in the specified
347  * directories first, and in the generic Python module directories (and in
348  * the current working directory) last. This avoids conflicts if there are
349  * Python modules which have the same name as a sigrok protocol decoder in
350  * sys.path or in the current working directory.
351  *
352  * @param path Path to the directory containing protocol decoders which shall
353  * be added to the Python sys.path, or NULL.
354  *
355  * @return SRD_OK upon success, a (negative) error code otherwise.
356  *
357  * @private
358  */
359 SRD_PRIV int srd_decoder_searchpath_add(const char *path)
360 {
361  PyObject *py_cur_path, *py_item;
362  PyGILState_STATE gstate;
363 
364  srd_dbg("Adding '%s' to module path.", path);
365 
366  gstate = PyGILState_Ensure();
367 
368  py_cur_path = PySys_GetObject("path");
369  if (!py_cur_path)
370  goto err;
371 
372  py_item = PyUnicode_FromString(path);
373  if (!py_item) {
374  srd_exception_catch("Failed to create Unicode object");
375  goto err;
376  }
377  if (PyList_Insert(py_cur_path, 0, py_item) < 0) {
378  srd_exception_catch("Failed to insert path element");
379  Py_DECREF(py_item);
380  goto err;
381  }
382  Py_DECREF(py_item);
383 
384  PyGILState_Release(gstate);
385 
386  searchpaths = g_slist_prepend(searchpaths, g_strdup(path));
387 
388  return SRD_OK;
389 
390 err:
391  PyGILState_Release(gstate);
392 
393  return SRD_ERR_PYTHON;
394 }
395 
396 /**
397  * Return the list of protocol decoder search paths.
398  *
399  * @return The list of search paths used when loading protocol decoders.
400  *
401  * @since 0.5.1
402  */
404 {
405  GSList *paths = NULL;
406 
407  for (GSList *l = searchpaths; l; l = l->next)
408  paths = g_slist_append(paths, g_strdup(l->data));
409 
410  return paths;
411 }
412 
413 /** @} */
#define SRD_PACKAGE_VERSION_STRING
The libsigrokdecode package version ("major.minor.micro") as string.
Definition: version.h:51
int srd_session_destroy(struct srd_session *sess)
Destroy a decoding session.
Definition: session.c:331
#define SRD_LIB_VERSION_STRING
The libsigrokdecode libtool version ("current:revision:age") as string.
Definition: version.h:67
#define SRD_API
No error.
const char * srd_package_version_string_get(void)
Get the libsigrokdecode package version number as a string.
Definition: version.c:95
The public libsigrokdecode header file to be used by frontends.
int srd_decoder_unload_all(void)
Unload all loaded protocol decoders.
Definition: decoder.c:1090
GSList * srd_searchpaths_get(void)
Return the list of protocol decoder search paths.
Definition: srd.c:403
Python C API error.
char * srd_buildinfo_host_get(void)
Definition: version.c:168
int srd_exit(void)
Shutdown libsigrokdecode.
Definition: srd.c:313
int srd_init(const char *path)
Initialize libsigrokdecode.
Definition: srd.c:219
#define SRD_PRIV
const char * srd_lib_version_string_get(void)
Get the libsigrokdecode library version number as a string.
Definition: version.c:144
Generic/unspecified error.
GSList * srd_buildinfo_libs_get(void)
Definition: version.c:149