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
_hb_blob_destroy_user_data(hb_blob_t * blob)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: (Xconstructor)
82 * @data: (array length=length) (closure user_data) (destroy destroy) (scope notified) (transfer none): 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: 1.0
95 **/
96 hb_blob_t *
hb_blob_create(const char * data,unsigned int length,hb_memory_mode_t mode,void * user_data,hb_destroy_func_t destroy)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 || !(blob = hb_object_create<hb_blob_t> ())) {
106 if (destroy)
107 destroy (user_data);
108 return hb_blob_get_empty ();
109 }
110
111 blob->data = data;
112 blob->length = length;
113 blob->mode = mode;
114
115 blob->user_data = user_data;
116 blob->destroy = destroy;
117
118 if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
119 blob->mode = HB_MEMORY_MODE_READONLY;
120 if (!_try_writable (blob)) {
121 hb_blob_destroy (blob);
122 return hb_blob_get_empty ();
123 }
124 }
125
126 return blob;
127 }
128
129 /**
130 * hb_blob_create_sub_blob:
131 * @parent: Parent blob.
132 * @offset: Start offset of sub-blob within @parent, in bytes.
133 * @length: Length of sub-blob.
134 *
135 * Returns a blob that represents a range of bytes in @parent. The new
136 * blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
137 * will never modify data in the parent blob. The parent data is not
138 * expected to be modified, and will result in undefined behavior if it
139 * is.
140 *
141 * Makes @parent immutable.
142 *
143 * Return value: New blob, or the empty blob if something failed or if
144 * @length is zero or @offset is beyond the end of @parent's data. Destroy
145 * with hb_blob_destroy().
146 *
147 * Since: 1.0
148 **/
149 hb_blob_t *
hb_blob_create_sub_blob(hb_blob_t * parent,unsigned int offset,unsigned int length)150 hb_blob_create_sub_blob (hb_blob_t *parent,
151 unsigned int offset,
152 unsigned int length)
153 {
154 hb_blob_t *blob;
155
156 if (!length || offset >= parent->length)
157 return hb_blob_get_empty ();
158
159 hb_blob_make_immutable (parent);
160
161 blob = hb_blob_create (parent->data + offset,
162 MIN (length, parent->length - offset),
163 HB_MEMORY_MODE_READONLY,
164 hb_blob_reference (parent),
165 (hb_destroy_func_t) hb_blob_destroy);
166
167 return blob;
168 }
169
170 /**
171 * hb_blob_get_empty:
172 *
173 * Returns the singleton empty blob.
174 *
175 * See TODO:link object types for more information.
176 *
177 * Return value: (transfer full): the empty blob.
178 *
179 * Since: 1.0
180 **/
181 hb_blob_t *
hb_blob_get_empty(void)182 hb_blob_get_empty (void)
183 {
184 static const hb_blob_t _hb_blob_nil = {
185 HB_OBJECT_HEADER_STATIC,
186
187 true, /* immutable */
188
189 NULL, /* data */
190 0, /* length */
191 HB_MEMORY_MODE_READONLY, /* mode */
192
193 NULL, /* user_data */
194 NULL /* destroy */
195 };
196
197 return const_cast<hb_blob_t *> (&_hb_blob_nil);
198 }
199
200 /**
201 * hb_blob_reference: (skip)
202 * @blob: a blob.
203 *
204 * Increases the reference count on @blob.
205 *
206 * See TODO:link object types for more information.
207 *
208 * Return value: @blob.
209 *
210 * Since: 1.0
211 **/
212 hb_blob_t *
hb_blob_reference(hb_blob_t * blob)213 hb_blob_reference (hb_blob_t *blob)
214 {
215 return hb_object_reference (blob);
216 }
217
218 /**
219 * hb_blob_destroy: (skip)
220 * @blob: a blob.
221 *
222 * Descreases the reference count on @blob, and if it reaches zero, destroys
223 * @blob, freeing all memory, possibly calling the destroy-callback the blob
224 * was created for if it has not been called already.
225 *
226 * See TODO:link object types for more information.
227 *
228 * Since: 1.0
229 **/
230 void
hb_blob_destroy(hb_blob_t * blob)231 hb_blob_destroy (hb_blob_t *blob)
232 {
233 if (!hb_object_destroy (blob)) return;
234
235 _hb_blob_destroy_user_data (blob);
236
237 free (blob);
238 }
239
240 /**
241 * hb_blob_set_user_data: (skip)
242 * @blob: a blob.
243 * @key: key for data to set.
244 * @data: data to set.
245 * @destroy: callback to call when @data is not needed anymore.
246 * @replace: whether to replace an existing data with the same key.
247 *
248 * Return value:
249 *
250 * Since: 1.0
251 **/
252 hb_bool_t
hb_blob_set_user_data(hb_blob_t * blob,hb_user_data_key_t * key,void * data,hb_destroy_func_t destroy,hb_bool_t replace)253 hb_blob_set_user_data (hb_blob_t *blob,
254 hb_user_data_key_t *key,
255 void * data,
256 hb_destroy_func_t destroy,
257 hb_bool_t replace)
258 {
259 return hb_object_set_user_data (blob, key, data, destroy, replace);
260 }
261
262 /**
263 * hb_blob_get_user_data: (skip)
264 * @blob: a blob.
265 * @key: key for data to get.
266 *
267 *
268 *
269 * Return value: (transfer none):
270 *
271 * Since: 1.0
272 **/
273 void *
hb_blob_get_user_data(hb_blob_t * blob,hb_user_data_key_t * key)274 hb_blob_get_user_data (hb_blob_t *blob,
275 hb_user_data_key_t *key)
276 {
277 return hb_object_get_user_data (blob, key);
278 }
279
280
281 /**
282 * hb_blob_make_immutable:
283 * @blob: a blob.
284 *
285 *
286 *
287 * Since: 1.0
288 **/
289 void
hb_blob_make_immutable(hb_blob_t * blob)290 hb_blob_make_immutable (hb_blob_t *blob)
291 {
292 if (hb_object_is_inert (blob))
293 return;
294
295 blob->immutable = true;
296 }
297
298 /**
299 * hb_blob_is_immutable:
300 * @blob: a blob.
301 *
302 *
303 *
304 * Return value: TODO
305 *
306 * Since: 1.0
307 **/
308 hb_bool_t
hb_blob_is_immutable(hb_blob_t * blob)309 hb_blob_is_immutable (hb_blob_t *blob)
310 {
311 return blob->immutable;
312 }
313
314
315 /**
316 * hb_blob_get_length:
317 * @blob: a blob.
318 *
319 *
320 *
321 * Return value: the length of blob data in bytes.
322 *
323 * Since: 1.0
324 **/
325 unsigned int
hb_blob_get_length(hb_blob_t * blob)326 hb_blob_get_length (hb_blob_t *blob)
327 {
328 return blob->length;
329 }
330
331 /**
332 * hb_blob_get_data:
333 * @blob: a blob.
334 * @length: (out):
335 *
336 *
337 *
338 * Returns: (transfer none) (array length=length):
339 *
340 * Since: 1.0
341 **/
342 const char *
hb_blob_get_data(hb_blob_t * blob,unsigned int * length)343 hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
344 {
345 if (length)
346 *length = blob->length;
347
348 return blob->data;
349 }
350
351 /**
352 * hb_blob_get_data_writable:
353 * @blob: a blob.
354 * @length: (out): output length of the writable data.
355 *
356 * Tries to make blob data writable (possibly copying it) and
357 * return pointer to data.
358 *
359 * Fails if blob has been made immutable, or if memory allocation
360 * fails.
361 *
362 * Returns: (transfer none) (array length=length): Writable blob data,
363 * or %NULL if failed.
364 *
365 * Since: 1.0
366 **/
367 char *
hb_blob_get_data_writable(hb_blob_t * blob,unsigned int * length)368 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
369 {
370 if (!_try_writable (blob)) {
371 if (length)
372 *length = 0;
373
374 return NULL;
375 }
376
377 if (length)
378 *length = blob->length;
379
380 return const_cast<char *> (blob->data);
381 }
382
383
384 static hb_bool_t
_try_make_writable_inplace_unix(hb_blob_t * blob)385 _try_make_writable_inplace_unix (hb_blob_t *blob)
386 {
387 #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
388 uintptr_t pagesize = -1, mask, length;
389 const char *addr;
390
391 #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
392 pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
393 #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
394 pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
395 #elif defined(HAVE_GETPAGESIZE)
396 pagesize = (uintptr_t) getpagesize ();
397 #endif
398
399 if ((uintptr_t) -1L == pagesize) {
400 DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
401 return false;
402 }
403 DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
404
405 mask = ~(pagesize-1);
406 addr = (const char *) (((uintptr_t) blob->data) & mask);
407 length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask) - addr;
408 DEBUG_MSG_FUNC (BLOB, blob,
409 "calling mprotect on [%p..%p] (%lu bytes)",
410 addr, addr+length, (unsigned long) length);
411 if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
412 DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
413 return false;
414 }
415
416 blob->mode = HB_MEMORY_MODE_WRITABLE;
417
418 DEBUG_MSG_FUNC (BLOB, blob,
419 "successfully made [%p..%p] (%lu bytes) writable\n",
420 addr, addr+length, (unsigned long) length);
421 return true;
422 #else
423 return false;
424 #endif
425 }
426
427 static bool
_try_writable_inplace(hb_blob_t * blob)428 _try_writable_inplace (hb_blob_t *blob)
429 {
430 DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
431
432 if (_try_make_writable_inplace_unix (blob))
433 return true;
434
435 DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
436
437 /* Failed to make writable inplace, mark that */
438 blob->mode = HB_MEMORY_MODE_READONLY;
439 return false;
440 }
441
442 static bool
_try_writable(hb_blob_t * blob)443 _try_writable (hb_blob_t *blob)
444 {
445 if (blob->immutable)
446 return false;
447
448 if (blob->mode == HB_MEMORY_MODE_WRITABLE)
449 return true;
450
451 if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
452 return true;
453
454 if (blob->mode == HB_MEMORY_MODE_WRITABLE)
455 return true;
456
457
458 DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
459
460 char *new_data;
461
462 new_data = (char *) malloc (blob->length);
463 if (unlikely (!new_data))
464 return false;
465
466 DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
467
468 memcpy (new_data, blob->data, blob->length);
469 _hb_blob_destroy_user_data (blob);
470 blob->mode = HB_MEMORY_MODE_WRITABLE;
471 blob->data = new_data;
472 blob->user_data = new_data;
473 blob->destroy = free;
474
475 return true;
476 }
477