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1 | /* | |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2015 Daniel Elstner <daniel.kitta@gmail.com> | |
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 3 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, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <config.h> | |
21 | #include <errno.h> | |
22 | #include <stdio.h> | |
23 | #include <glib.h> | |
24 | #include <glib/gstdio.h> | |
25 | #include <libsigrok/libsigrok.h> | |
26 | #include "libsigrok-internal.h" | |
27 | ||
28 | /** @cond PRIVATE */ | |
29 | #define LOG_PREFIX "resource" | |
30 | /** @endcond */ | |
31 | ||
32 | /** | |
33 | * @file | |
34 | * | |
35 | * Access to resource files. | |
36 | */ | |
37 | ||
38 | /** | |
39 | * Get a list of paths where we look for resource (e.g. firmware) files. | |
40 | * | |
41 | * @param res_type The type of resource to get the search paths for. | |
42 | * | |
43 | * @return List of strings that must be freed after use, including the strings. | |
44 | * | |
45 | * @since 0.6.0 | |
46 | */ | |
47 | SR_API GSList *sr_resourcepaths_get(int res_type) | |
48 | { | |
49 | const char *subdir = NULL; | |
50 | GSList *l = NULL; | |
51 | const char *env; | |
52 | const char *const *datadirs; | |
53 | ||
54 | if (res_type == SR_RESOURCE_FIRMWARE) { | |
55 | subdir = "sigrok-firmware"; | |
56 | ||
57 | env = g_getenv("SIGROK_FIRMWARE_DIR"); | |
58 | if (!env) | |
59 | sr_dbg("SIGROK_FIRMWARE_DIR environment variable not set, ignoring."); | |
60 | else | |
61 | l = g_slist_append(l, g_strdup(env)); | |
62 | } | |
63 | ||
64 | l = g_slist_append(l, g_build_filename(g_get_user_data_dir(), subdir, NULL)); | |
65 | ||
66 | #ifdef FIRMWARE_DIR | |
67 | if (res_type == SR_RESOURCE_FIRMWARE) { | |
68 | /* | |
69 | * Scan the hard-coded directory before the system directories to | |
70 | * avoid picking up possibly outdated files from a system install. | |
71 | */ | |
72 | l = g_slist_append(l, g_strdup(FIRMWARE_DIR)); | |
73 | } | |
74 | #endif | |
75 | ||
76 | datadirs = g_get_system_data_dirs(); | |
77 | while (*datadirs) | |
78 | l = g_slist_append(l, g_build_filename(*datadirs++, subdir, NULL)); | |
79 | ||
80 | return l; | |
81 | } | |
82 | ||
83 | /** | |
84 | * Retrieve the size of the open stream @a file. | |
85 | * | |
86 | * This function only works on seekable streams. However, the set of seekable | |
87 | * streams is generally congruent with the set of streams that have a size. | |
88 | * Code that needs to work with any type of stream (including pipes) should | |
89 | * require neither seekability nor advance knowledge of the size. | |
90 | * On failure, the return value is negative and errno is set. | |
91 | * | |
92 | * @param file An I/O stream opened in binary mode. | |
93 | * @return The size of @a file in bytes, or a negative value on failure. | |
94 | * | |
95 | * @private | |
96 | */ | |
97 | SR_PRIV int64_t sr_file_get_size(FILE *file) | |
98 | { | |
99 | off_t filepos, filesize; | |
100 | ||
101 | /* ftello() and fseeko() are not standard C, but part of POSIX.1-2001. | |
102 | * Thus, if these functions are available at all, they can reasonably | |
103 | * be expected to also conform to POSIX semantics. In particular, this | |
104 | * means that ftello() after fseeko(..., SEEK_END) has a defined result | |
105 | * and can be used to get the size of a seekable stream. | |
106 | * On Windows, the result is fully defined only for binary streams. | |
107 | */ | |
108 | filepos = ftello(file); | |
109 | if (filepos < 0) | |
110 | return -1; | |
111 | ||
112 | if (fseeko(file, 0, SEEK_END) < 0) | |
113 | return -1; | |
114 | ||
115 | filesize = ftello(file); | |
116 | if (filesize < 0) | |
117 | return -1; | |
118 | ||
119 | if (fseeko(file, filepos, SEEK_SET) < 0) | |
120 | return -1; | |
121 | ||
122 | return filesize; | |
123 | } | |
124 | ||
125 | static FILE *try_open_file(const char *datadir, const char *subdir, | |
126 | const char *name) | |
127 | { | |
128 | char *filename; | |
129 | FILE *file; | |
130 | ||
131 | if (subdir) | |
132 | filename = g_build_filename(datadir, subdir, name, NULL); | |
133 | else | |
134 | filename = g_build_filename(datadir, name, NULL); | |
135 | ||
136 | file = g_fopen(filename, "rb"); | |
137 | ||
138 | if (file) | |
139 | sr_info("Opened '%s'.", filename); | |
140 | else | |
141 | sr_spew("Attempt to open '%s' failed: %s", | |
142 | filename, g_strerror(errno)); | |
143 | g_free(filename); | |
144 | ||
145 | return file; | |
146 | } | |
147 | ||
148 | static int resource_open_default(struct sr_resource *res, | |
149 | const char *name, void *cb_data) | |
150 | { | |
151 | GSList *paths, *p = NULL; | |
152 | int64_t filesize; | |
153 | FILE *file = NULL; | |
154 | ||
155 | (void)cb_data; | |
156 | ||
157 | paths = sr_resourcepaths_get(res->type); | |
158 | ||
159 | /* Currently, the enum only defines SR_RESOURCE_FIRMWARE. */ | |
160 | if (res->type != SR_RESOURCE_FIRMWARE) { | |
161 | sr_err("%s: unknown type %d.", __func__, res->type); | |
162 | return SR_ERR_ARG; | |
163 | } | |
164 | ||
165 | p = paths; | |
166 | while (p && !file) { | |
167 | file = try_open_file((const char *)(p->data), NULL, name); | |
168 | p = p->next; | |
169 | } | |
170 | g_slist_free_full(paths, g_free); | |
171 | ||
172 | if (!file) { | |
173 | sr_dbg("Failed to locate '%s'.", name); | |
174 | return SR_ERR; | |
175 | } | |
176 | ||
177 | filesize = sr_file_get_size(file); | |
178 | if (filesize < 0) { | |
179 | sr_err("Failed to obtain size of '%s': %s", | |
180 | name, g_strerror(errno)); | |
181 | fclose(file); | |
182 | return SR_ERR; | |
183 | } | |
184 | res->size = filesize; | |
185 | res->handle = file; | |
186 | ||
187 | return SR_OK; | |
188 | } | |
189 | ||
190 | static int resource_close_default(struct sr_resource *res, void *cb_data) | |
191 | { | |
192 | FILE *file; | |
193 | ||
194 | (void)cb_data; | |
195 | ||
196 | file = res->handle; | |
197 | if (!file) { | |
198 | sr_err("%s: invalid handle.", __func__); | |
199 | return SR_ERR_ARG; | |
200 | } | |
201 | ||
202 | if (fclose(file) < 0) { | |
203 | sr_err("Failed to close file: %s", g_strerror(errno)); | |
204 | return SR_ERR; | |
205 | } | |
206 | res->handle = NULL; | |
207 | ||
208 | return SR_OK; | |
209 | } | |
210 | ||
211 | static gssize resource_read_default(const struct sr_resource *res, | |
212 | void *buf, size_t count, void *cb_data) | |
213 | { | |
214 | FILE *file; | |
215 | size_t n_read; | |
216 | ||
217 | (void)cb_data; | |
218 | ||
219 | file = res->handle; | |
220 | if (!file) { | |
221 | sr_err("%s: invalid handle.", __func__); | |
222 | return SR_ERR_ARG; | |
223 | } | |
224 | if (count > G_MAXSSIZE) { | |
225 | sr_err("%s: count %zu too large.", __func__, count); | |
226 | return SR_ERR_ARG; | |
227 | } | |
228 | ||
229 | n_read = fread(buf, 1, count, file); | |
230 | ||
231 | if (n_read != count && ferror(file)) { | |
232 | sr_err("Failed to read resource file: %s", g_strerror(errno)); | |
233 | return SR_ERR; | |
234 | } | |
235 | return n_read; | |
236 | } | |
237 | ||
238 | /** | |
239 | * Install resource access hooks. | |
240 | * | |
241 | * @param ctx libsigrok context. Must not be NULL. | |
242 | * @param open_cb Resource open callback, or NULL to unset. | |
243 | * @param close_cb Resource close callback, or NULL to unset. | |
244 | * @param read_cb Resource read callback, or NULL to unset. | |
245 | * @param cb_data User data pointer passed to callbacks. | |
246 | * | |
247 | * @retval SR_OK Success. | |
248 | * @retval SR_ERR_ARG Invalid argument. | |
249 | * | |
250 | * @since 0.4.0 | |
251 | */ | |
252 | SR_API int sr_resource_set_hooks(struct sr_context *ctx, | |
253 | sr_resource_open_callback open_cb, | |
254 | sr_resource_close_callback close_cb, | |
255 | sr_resource_read_callback read_cb, void *cb_data) | |
256 | { | |
257 | if (!ctx) { | |
258 | sr_err("%s: ctx was NULL.", __func__); | |
259 | return SR_ERR_ARG; | |
260 | } | |
261 | if (open_cb && close_cb && read_cb) { | |
262 | ctx->resource_open_cb = open_cb; | |
263 | ctx->resource_close_cb = close_cb; | |
264 | ctx->resource_read_cb = read_cb; | |
265 | ctx->resource_cb_data = cb_data; | |
266 | } else if (!open_cb && !close_cb && !read_cb) { | |
267 | ctx->resource_open_cb = &resource_open_default; | |
268 | ctx->resource_close_cb = &resource_close_default; | |
269 | ctx->resource_read_cb = &resource_read_default; | |
270 | ctx->resource_cb_data = ctx; | |
271 | } else { | |
272 | sr_err("%s: inconsistent callback pointers.", __func__); | |
273 | return SR_ERR_ARG; | |
274 | } | |
275 | return SR_OK; | |
276 | } | |
277 | ||
278 | /** | |
279 | * Open resource. | |
280 | * | |
281 | * @param ctx libsigrok context. Must not be NULL. | |
282 | * @param[out] res Resource descriptor to fill in. Must not be NULL. | |
283 | * @param type Resource type ID. | |
284 | * @param name Name of the resource. Must not be NULL. | |
285 | * | |
286 | * @retval SR_OK Success. | |
287 | * @retval SR_ERR_ARG Invalid argument. | |
288 | * @retval SR_ERR Other error. | |
289 | * | |
290 | * @private | |
291 | */ | |
292 | SR_PRIV int sr_resource_open(struct sr_context *ctx, | |
293 | struct sr_resource *res, int type, const char *name) | |
294 | { | |
295 | int ret; | |
296 | ||
297 | res->size = 0; | |
298 | res->handle = NULL; | |
299 | res->type = type; | |
300 | ||
301 | ret = (*ctx->resource_open_cb)(res, name, ctx->resource_cb_data); | |
302 | ||
303 | if (ret != SR_OK) | |
304 | sr_err("Failed to open resource '%s' (use loglevel 5/spew for" | |
305 | " details).", name); | |
306 | ||
307 | return ret; | |
308 | } | |
309 | ||
310 | /** | |
311 | * Close resource. | |
312 | * | |
313 | * @param ctx libsigrok context. Must not be NULL. | |
314 | * @param[inout] res Resource descriptor. Must not be NULL. | |
315 | * | |
316 | * @retval SR_OK Success. | |
317 | * @retval SR_ERR_ARG Invalid argument. | |
318 | * @retval SR_ERR Other error. | |
319 | * | |
320 | * @private | |
321 | */ | |
322 | SR_PRIV int sr_resource_close(struct sr_context *ctx, struct sr_resource *res) | |
323 | { | |
324 | int ret; | |
325 | ||
326 | ret = (*ctx->resource_close_cb)(res, ctx->resource_cb_data); | |
327 | ||
328 | if (ret != SR_OK) | |
329 | sr_err("Failed to close resource."); | |
330 | ||
331 | return ret; | |
332 | } | |
333 | ||
334 | /** | |
335 | * Read resource data. | |
336 | * | |
337 | * @param ctx libsigrok context. Must not be NULL. | |
338 | * @param[in] res Resource descriptor. Must not be NULL. | |
339 | * @param[out] buf Buffer to store @a count bytes into. Must not be NULL. | |
340 | * @param count Number of bytes to read. | |
341 | * | |
342 | * @return The number of bytes actually read, or a negative value on error. | |
343 | * @retval SR_ERR_ARG Invalid argument. | |
344 | * @retval SR_ERR Other error. | |
345 | * | |
346 | * @private | |
347 | */ | |
348 | SR_PRIV gssize sr_resource_read(struct sr_context *ctx, | |
349 | const struct sr_resource *res, void *buf, size_t count) | |
350 | { | |
351 | gssize n_read; | |
352 | ||
353 | n_read = (*ctx->resource_read_cb)(res, buf, count, | |
354 | ctx->resource_cb_data); | |
355 | if (n_read < 0) | |
356 | sr_err("Failed to read resource."); | |
357 | ||
358 | return n_read; | |
359 | } | |
360 | ||
361 | /** | |
362 | * Load a resource into memory. | |
363 | * | |
364 | * @param ctx libsigrok context. Must not be NULL. | |
365 | * @param type Resource type ID. | |
366 | * @param name Name of the resource. Must not be NULL. | |
367 | * @param[out] size Size in bytes of the returned buffer. Must not be NULL. | |
368 | * @param max_size Size limit. Error out if the resource is larger than this. | |
369 | * | |
370 | * @return A buffer containing the resource data, or NULL on failure. Must | |
371 | * be freed by the caller using g_free(). | |
372 | * | |
373 | * @private | |
374 | */ | |
375 | SR_PRIV void *sr_resource_load(struct sr_context *ctx, | |
376 | int type, const char *name, size_t *size, size_t max_size) | |
377 | { | |
378 | struct sr_resource res; | |
379 | void *buf; | |
380 | size_t res_size; | |
381 | gssize n_read; | |
382 | ||
383 | if (sr_resource_open(ctx, &res, type, name) != SR_OK) | |
384 | return NULL; | |
385 | ||
386 | if (res.size > max_size) { | |
387 | sr_err("Size %" PRIu64 " of '%s' exceeds limit %zu.", | |
388 | res.size, name, max_size); | |
389 | sr_resource_close(ctx, &res); | |
390 | return NULL; | |
391 | } | |
392 | res_size = res.size; | |
393 | ||
394 | buf = g_try_malloc(res_size); | |
395 | if (!buf) { | |
396 | sr_err("Failed to allocate buffer for '%s'.", name); | |
397 | sr_resource_close(ctx, &res); | |
398 | return NULL; | |
399 | } | |
400 | ||
401 | n_read = sr_resource_read(ctx, &res, buf, res_size); | |
402 | sr_resource_close(ctx, &res); | |
403 | ||
404 | if (n_read < 0 || (size_t)n_read != res_size) { | |
405 | if (n_read >= 0) | |
406 | sr_err("Failed to read '%s': premature end of file.", | |
407 | name); | |
408 | g_free(buf); | |
409 | return NULL; | |
410 | } | |
411 | ||
412 | *size = res_size; | |
413 | return buf; | |
414 | } | |
415 | ||
416 | /** @} */ |