1 /*
2 * Copyright © 2009 Red Hat, Inc.
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Red Hat Author(s): Behdad Esfahbod
25 */
26
27 /* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
28 #ifndef _POSIX_C_SOURCE
29 #define _POSIX_C_SOURCE 199309L
30 #endif
31
32 #include "hb-private.hh"
33
34 #include "hb-object-private.hh"
35
36 #ifdef HAVE_SYS_MMAN_H
37 #ifdef HAVE_UNISTD_H
38 #include <unistd.h>
39 #endif /* HAVE_UNISTD_H */
40 #include <sys/mman.h>
41 #endif /* HAVE_SYS_MMAN_H */
42
43 #include <stdio.h>
44 #include <errno.h>
45
46
47
48 #ifndef HB_DEBUG_BLOB
49 #define HB_DEBUG_BLOB (HB_DEBUG+0)
50 #endif
51
52
53 struct hb_blob_t {
54 hb_object_header_t header;
55 ASSERT_POD ();
56
57 bool immutable;
58
59 const char *data;
60 unsigned int length;
61 hb_memory_mode_t mode;
62
63 void *user_data;
64 hb_destroy_func_t destroy;
65 };
66
67
68 static bool _try_writable (hb_blob_t *blob);
69
70 static void
71 _hb_blob_destroy_user_data (hb_blob_t *blob)
72 {
73 if (blob->destroy) {
74 blob->destroy (blob->user_data);
75 blob->user_data = NULL;
76 blob->destroy = NULL;
77 }
78 }
79
80 /**
81 * hb_blob_create: (skip)
82 * @data: Pointer to blob data.
83 * @length: Length of @data in bytes.
84 * @mode: Memory mode for @data.
85 * @user_data: Data parameter to pass to @destroy.
86 * @destroy: Callback to call when @data is not needed anymore.
87 *
88 * Creates a new "blob" object wrapping @data. The @mode parameter is used
89 * to negotiate ownership and lifecycle of @data.
90 *
91 * Return value: New blob, or the empty blob if something failed or if @length is
92 * zero. Destroy with hb_blob_destroy().
93 *
94 * Since: 0.9.2
95 **/
96 hb_blob_t *
97 hb_blob_create (const char *data,
98 unsigned int length,
99 hb_memory_mode_t mode,
100 void *user_data,
101 hb_destroy_func_t destroy)
102 {
103 hb_blob_t *blob;
104
105 if (!length ||
106 length >= 1u << 31 ||
107 !(blob = hb_object_create<hb_blob_t> ())) {
108 if (destroy)
109 destroy (user_data);
110 return hb_blob_get_empty ();
111 }
112
113 blob->data = data;
114 blob->length = length;
115 blob->mode = mode;
116
117 blob->user_data = user_data;
118 blob->destroy = destroy;
119
120 if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
121 blob->mode = HB_MEMORY_MODE_READONLY;
122 if (!_try_writable (blob)) {
123 hb_blob_destroy (blob);
124 return hb_blob_get_empty ();
125 }
126 }
127
128 return blob;
129 }
130
131 /**
132 * hb_blob_create_sub_blob:
133 * @parent: Parent blob.
134 * @offset: Start offset of sub-blob within @parent, in bytes.
135 * @length: Length of sub-blob.
136 *
137 * Returns a blob that represents a range of bytes in @parent. The new
138 * blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
139 * will never modify data in the parent blob. The parent data is not
140 * expected to be modified, and will result in undefined behavior if it
141 * is.
142 *
143 * Makes @parent immutable.
144 *
145 * Return value: New blob, or the empty blob if something failed or if
146 * @length is zero or @offset is beyond the end of @parent's data. Destroy
147 * with hb_blob_destroy().
148 *
149 * Since: 0.9.2
150 **/
151 hb_blob_t *
152 hb_blob_create_sub_blob (hb_blob_t *parent,
153 unsigned int offset,
154 unsigned int length)
155 {
156 hb_blob_t *blob;
157
158 if (!length || offset >= parent->length)
159 return hb_blob_get_empty ();
160
161 hb_blob_make_immutable (parent);
162
163 blob = hb_blob_create (parent->data + offset,
164 MIN (length, parent->length - offset),
165 HB_MEMORY_MODE_READONLY,
166 hb_blob_reference (parent),
167 (hb_destroy_func_t) hb_blob_destroy);
168
169 return blob;
170 }
171
172 /**
173 * hb_blob_get_empty:
174 *
175 * Returns the singleton empty blob.
176 *
177 * See TODO:link object types for more information.
178 *
179 * Return value: (transfer full): the empty blob.
180 *
181 * Since: 0.9.2
182 **/
183 hb_blob_t *
184 hb_blob_get_empty (void)
185 {
186 static const hb_blob_t _hb_blob_nil = {
187 HB_OBJECT_HEADER_STATIC,
188
189 true, /* immutable */
190
191 NULL, /* data */
192 0, /* length */
193 HB_MEMORY_MODE_READONLY, /* mode */
194
195 NULL, /* user_data */
196 NULL /* destroy */
197 };
198
199 return const_cast<hb_blob_t *> (&_hb_blob_nil);
200 }
201
202 /**
203 * hb_blob_reference: (skip)
204 * @blob: a blob.
205 *
206 * Increases the reference count on @blob.
207 *
208 * See TODO:link object types for more information.
209 *
210 * Return value: @blob.
211 *
212 * Since: 0.9.2
213 **/
214 hb_blob_t *
215 hb_blob_reference (hb_blob_t *blob)
216 {
217 return hb_object_reference (blob);
218 }
219
220 /**
221 * hb_blob_destroy: (skip)
222 * @blob: a blob.
223 *
224 * Descreases the reference count on @blob, and if it reaches zero, destroys
225 * @blob, freeing all memory, possibly calling the destroy-callback the blob
226 * was created for if it has not been called already.
227 *
228 * See TODO:link object types for more information.
229 *
230 * Since: 0.9.2
231 **/
232 void
233 hb_blob_destroy (hb_blob_t *blob)
234 {
235 if (!hb_object_destroy (blob)) return;
236
237 _hb_blob_destroy_user_data (blob);
238
239 free (blob);
240 }
241
242 /**
243 * hb_blob_set_user_data: (skip)
244 * @blob: a blob.
245 * @key: key for data to set.
246 * @data: data to set.
247 * @destroy: callback to call when @data is not needed anymore.
248 * @replace: whether to replace an existing data with the same key.
249 *
250 * Return value:
251 *
252 * Since: 0.9.2
253 **/
254 hb_bool_t
255 hb_blob_set_user_data (hb_blob_t *blob,
256 hb_user_data_key_t *key,
257 void * data,
258 hb_destroy_func_t destroy,
259 hb_bool_t replace)
260 {
261 return hb_object_set_user_data (blob, key, data, destroy, replace);
262 }
263
264 /**
265 * hb_blob_get_user_data: (skip)
266 * @blob: a blob.
267 * @key: key for data to get.
268 *
269 *
270 *
271 * Return value: (transfer none):
272 *
273 * Since: 0.9.2
274 **/
275 void *
276 hb_blob_get_user_data (hb_blob_t *blob,
277 hb_user_data_key_t *key)
278 {
279 return hb_object_get_user_data (blob, key);
280 }
281
282
283 /**
284 * hb_blob_make_immutable:
285 * @blob: a blob.
286 *
287 *
288 *
289 * Since: 0.9.2
290 **/
291 void
292 hb_blob_make_immutable (hb_blob_t *blob)
293 {
294 if (hb_object_is_inert (blob))
295 return;
296
297 blob->immutable = true;
298 }
299
300 /**
301 * hb_blob_is_immutable:
302 * @blob: a blob.
303 *
304 *
305 *
306 * Return value: TODO
307 *
308 * Since: 0.9.2
309 **/
310 hb_bool_t
311 hb_blob_is_immutable (hb_blob_t *blob)
312 {
313 return blob->immutable;
314 }
315
316
317 /**
318 * hb_blob_get_length:
319 * @blob: a blob.
320 *
321 *
322 *
323 * Return value: the length of blob data in bytes.
324 *
325 * Since: 0.9.2
326 **/
327 unsigned int
328 hb_blob_get_length (hb_blob_t *blob)
329 {
330 return blob->length;
331 }
332
333 /**
334 * hb_blob_get_data:
335 * @blob: a blob.
336 * @length: (out):
337 *
338 *
339 *
340 * Returns: (transfer none) (array length=length):
341 *
342 * Since: 0.9.2
343 **/
344 const char *
345 hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
346 {
347 if (length)
348 *length = blob->length;
349
350 return blob->data;
351 }
352
353 /**
354 * hb_blob_get_data_writable:
355 * @blob: a blob.
356 * @length: (out): output length of the writable data.
357 *
358 * Tries to make blob data writable (possibly copying it) and
359 * return pointer to data.
360 *
361 * Fails if blob has been made immutable, or if memory allocation
362 * fails.
363 *
364 * Returns: (transfer none) (array length=length): Writable blob data,
365 * or %NULL if failed.
366 *
367 * Since: 0.9.2
368 **/
369 char *
370 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
371 {
372 if (!_try_writable (blob)) {
373 if (length)
374 *length = 0;
375
376 return NULL;
377 }
378
379 if (length)
380 *length = blob->length;
381
382 return const_cast<char *> (blob->data);
383 }
384
385
386 static hb_bool_t
387 _try_make_writable_inplace_unix (hb_blob_t *blob)
388 {
389 #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
390 uintptr_t pagesize = -1, mask, length;
391 const char *addr;
392
393 #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
394 pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
395 #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
396 pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
397 #elif defined(HAVE_GETPAGESIZE)
398 pagesize = (uintptr_t) getpagesize ();
399 #endif
400
401 if ((uintptr_t) -1L == pagesize) {
402 DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
403 return false;
404 }
405 DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
406
407 mask = ~(pagesize-1);
408 addr = (const char *) (((uintptr_t) blob->data) & mask);
409 length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask) - addr;
410 DEBUG_MSG_FUNC (BLOB, blob,
411 "calling mprotect on [%p..%p] (%lu bytes)",
412 addr, addr+length, (unsigned long) length);
413 if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
414 DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
415 return false;
416 }
417
418 blob->mode = HB_MEMORY_MODE_WRITABLE;
419
420 DEBUG_MSG_FUNC (BLOB, blob,
421 "successfully made [%p..%p] (%lu bytes) writable\n",
422 addr, addr+length, (unsigned long) length);
423 return true;
424 #else
425 return false;
426 #endif
427 }
428
429 static bool
430 _try_writable_inplace (hb_blob_t *blob)
431 {
432 DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
433
434 if (_try_make_writable_inplace_unix (blob))
435 return true;
436
437 DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
438
439 /* Failed to make writable inplace, mark that */
440 blob->mode = HB_MEMORY_MODE_READONLY;
441 return false;
442 }
443
444 static bool
445 _try_writable (hb_blob_t *blob)
446 {
447 if (blob->immutable)
448 return false;
449
450 if (blob->mode == HB_MEMORY_MODE_WRITABLE)
451 return true;
452
453 if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
454 return true;
455
456 if (blob->mode == HB_MEMORY_MODE_WRITABLE)
457 return true;
458
459
460 DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
461
462 char *new_data;
463
464 new_data = (char *) malloc (blob->length);
465 if (unlikely (!new_data))
466 return false;
467
468 DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
469
470 memcpy (new_data, blob->data, blob->length);
471 _hb_blob_destroy_user_data (blob);
472 blob->mode = HB_MEMORY_MODE_WRITABLE;
473 blob->data = new_data;
474 blob->user_data = new_data;
475 blob->destroy = free;
476
477 return true;
478 }