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 : #include "hb-private.hh"
28 :
29 : #include "hb-blob.h"
30 : #include "hb-object-private.hh"
31 :
32 : #ifdef HAVE_SYS_MMAN_H
33 : #ifdef HAVE_UNISTD_H
34 : #include <unistd.h>
35 : #endif /* HAVE_UNISTD_H */
36 : #include <sys/mman.h>
37 : #endif /* HAVE_SYS_MMAN_H */
38 :
39 : #include <stdio.h>
40 : #include <errno.h>
41 :
42 :
43 :
44 : #ifndef HB_DEBUG_BLOB
45 : #define HB_DEBUG_BLOB (HB_DEBUG+0)
46 : #endif
47 :
48 :
49 : struct _hb_blob_t {
50 : hb_object_header_t header;
51 :
52 : bool immutable;
53 :
54 : const char *data;
55 : unsigned int length;
56 : hb_memory_mode_t mode;
57 :
58 : void *user_data;
59 : hb_destroy_func_t destroy;
60 : };
61 :
62 : static hb_blob_t _hb_blob_nil = {
63 : HB_OBJECT_HEADER_STATIC,
64 :
65 : TRUE, /* immutable */
66 :
67 : NULL, /* data */
68 : 0, /* length */
69 : HB_MEMORY_MODE_READONLY, /* mode */
70 :
71 : NULL, /* user_data */
72 : NULL /* destroy */
73 1464 : };
74 :
75 :
76 : static bool _try_writable (hb_blob_t *blob);
77 :
78 : static void
79 0 : _hb_blob_destroy_user_data (hb_blob_t *blob)
80 : {
81 0 : if (blob->destroy) {
82 0 : blob->destroy (blob->user_data);
83 0 : blob->user_data = NULL;
84 0 : blob->destroy = NULL;
85 : }
86 0 : }
87 :
88 : hb_blob_t *
89 0 : hb_blob_create (const char *data,
90 : unsigned int length,
91 : hb_memory_mode_t mode,
92 : void *user_data,
93 : hb_destroy_func_t destroy)
94 : {
95 : hb_blob_t *blob;
96 :
97 0 : if (!length || !(blob = hb_object_create<hb_blob_t> ())) {
98 0 : if (destroy)
99 0 : destroy (user_data);
100 0 : return &_hb_blob_nil;
101 : }
102 :
103 0 : blob->data = data;
104 0 : blob->length = length;
105 0 : blob->mode = mode;
106 :
107 0 : blob->user_data = user_data;
108 0 : blob->destroy = destroy;
109 :
110 0 : if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
111 0 : blob->mode = HB_MEMORY_MODE_READONLY;
112 0 : if (!_try_writable (blob)) {
113 0 : hb_blob_destroy (blob);
114 0 : return &_hb_blob_nil;
115 : }
116 : }
117 :
118 0 : return blob;
119 : }
120 :
121 : hb_blob_t *
122 0 : hb_blob_create_sub_blob (hb_blob_t *parent,
123 : unsigned int offset,
124 : unsigned int length)
125 : {
126 : hb_blob_t *blob;
127 :
128 0 : if (!length || offset >= parent->length)
129 0 : return &_hb_blob_nil;
130 :
131 0 : hb_blob_make_immutable (parent);
132 :
133 : blob = hb_blob_create (parent->data + offset,
134 : MIN (length, parent->length - offset),
135 : parent->mode,
136 0 : hb_blob_reference (parent),
137 0 : (hb_destroy_func_t) hb_blob_destroy);
138 :
139 0 : return blob;
140 : }
141 :
142 : hb_blob_t *
143 0 : hb_blob_get_empty (void)
144 : {
145 0 : return &_hb_blob_nil;
146 : }
147 :
148 : hb_blob_t *
149 0 : hb_blob_reference (hb_blob_t *blob)
150 : {
151 0 : return hb_object_reference (blob);
152 : }
153 :
154 : void
155 0 : hb_blob_destroy (hb_blob_t *blob)
156 : {
157 0 : if (!hb_object_destroy (blob)) return;
158 :
159 0 : _hb_blob_destroy_user_data (blob);
160 :
161 0 : free (blob);
162 : }
163 :
164 : hb_bool_t
165 0 : hb_blob_set_user_data (hb_blob_t *blob,
166 : hb_user_data_key_t *key,
167 : void * data,
168 : hb_destroy_func_t destroy,
169 : hb_bool_t replace)
170 : {
171 0 : return hb_object_set_user_data (blob, key, data, destroy, replace);
172 : }
173 :
174 : void *
175 0 : hb_blob_get_user_data (hb_blob_t *blob,
176 : hb_user_data_key_t *key)
177 : {
178 0 : return hb_object_get_user_data (blob, key);
179 : }
180 :
181 :
182 : void
183 0 : hb_blob_make_immutable (hb_blob_t *blob)
184 : {
185 0 : if (hb_object_is_inert (blob))
186 0 : return;
187 :
188 0 : blob->immutable = TRUE;
189 : }
190 :
191 : hb_bool_t
192 0 : hb_blob_is_immutable (hb_blob_t *blob)
193 : {
194 0 : return blob->immutable;
195 : }
196 :
197 :
198 : unsigned int
199 0 : hb_blob_get_length (hb_blob_t *blob)
200 : {
201 0 : return blob->length;
202 : }
203 :
204 : const char *
205 0 : hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
206 : {
207 0 : if (length)
208 0 : *length = blob->length;
209 :
210 0 : return blob->data;
211 : }
212 :
213 : char *
214 0 : hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
215 : {
216 0 : if (!_try_writable (blob)) {
217 0 : if (length)
218 0 : *length = 0;
219 :
220 0 : return NULL;
221 : }
222 :
223 0 : if (length)
224 0 : *length = blob->length;
225 :
226 0 : return const_cast<char *> (blob->data);
227 : }
228 :
229 :
230 : static hb_bool_t
231 0 : _try_make_writable_inplace_unix (hb_blob_t *blob)
232 : {
233 : #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
234 : uintptr_t pagesize = -1, mask, length;
235 : const char *addr;
236 :
237 : #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
238 : pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
239 : #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
240 : pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
241 : #elif defined(HAVE_GETPAGESIZE)
242 : pagesize = (uintptr_t) getpagesize ();
243 : #endif
244 :
245 : if ((uintptr_t) -1L == pagesize) {
246 : DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
247 : return FALSE;
248 : }
249 : DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
250 :
251 : mask = ~(pagesize-1);
252 : addr = (const char *) (((uintptr_t) blob->data) & mask);
253 : length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask) - addr;
254 : DEBUG_MSG_FUNC (BLOB, blob,
255 : "calling mprotect on [%p..%p] (%lu bytes)",
256 : addr, addr+length, (unsigned long) length);
257 : if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
258 : DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
259 : return FALSE;
260 : }
261 :
262 : blob->mode = HB_MEMORY_MODE_WRITABLE;
263 :
264 : DEBUG_MSG_FUNC (BLOB, blob,
265 : "successfully made [%p..%p] (%lu bytes) writable\n",
266 : addr, addr+length, (unsigned long) length);
267 : return TRUE;
268 : #else
269 0 : return FALSE;
270 : #endif
271 : }
272 :
273 : static bool
274 0 : _try_writable_inplace (hb_blob_t *blob)
275 : {
276 0 : DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
277 :
278 0 : if (_try_make_writable_inplace_unix (blob))
279 0 : return TRUE;
280 :
281 0 : DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
282 :
283 : /* Failed to make writable inplace, mark that */
284 0 : blob->mode = HB_MEMORY_MODE_READONLY;
285 0 : return FALSE;
286 : }
287 :
288 : static bool
289 0 : _try_writable (hb_blob_t *blob)
290 : {
291 0 : if (blob->immutable)
292 0 : return FALSE;
293 :
294 0 : if (blob->mode == HB_MEMORY_MODE_WRITABLE)
295 0 : return TRUE;
296 :
297 0 : if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
298 0 : return TRUE;
299 :
300 0 : if (blob->mode == HB_MEMORY_MODE_WRITABLE)
301 0 : return TRUE;
302 :
303 :
304 0 : DEBUG_MSG_FUNC (BLOB, blob, "currect data is -> %p\n", blob->data);
305 :
306 : char *new_data;
307 :
308 0 : new_data = (char *) malloc (blob->length);
309 0 : if (unlikely (!new_data))
310 0 : return FALSE;
311 :
312 0 : DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
313 :
314 0 : memcpy (new_data, blob->data, blob->length);
315 0 : _hb_blob_destroy_user_data (blob);
316 0 : blob->mode = HB_MEMORY_MODE_WRITABLE;
317 0 : blob->data = new_data;
318 0 : blob->user_data = new_data;
319 0 : blob->destroy = free;
320 :
321 0 : return TRUE;
322 4392 : }
323 :
324 :
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