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