third_party/harfbuzz-ng/src/hb-blob.cc

   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: 1.0
  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       data + length < data /* overflows */ ||
 108       !(blob = hb_object_create<hb_blob_t> ())) {
 109     if (destroy)
 110       destroy (user_data);
 111     return hb_blob_get_empty ();
 112   }
 113
 114   blob->data = data;
 115   blob->length = length;
 116   blob->mode = mode;
 117
 118   blob->user_data = user_data;
 119   blob->destroy = destroy;
 120
 121   if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
 122     blob->mode = HB_MEMORY_MODE_READONLY;
 123     if (!_try_writable (blob)) {
 124       hb_blob_destroy (blob);
 125       return hb_blob_get_empty ();
 126     }
 127   }
 128
 129   return blob;
 130 }
 131
 132 /**
 133  * hb_blob_create_sub_blob:
 134  * @parent: Parent blob.
 135  * @offset: Start offset of sub-blob within @parent, in bytes.
 136  * @length: Length of sub-blob.
 137  *
 138  * Returns a blob that represents a range of bytes in @parent.  The new
 139  * blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
 140  * will never modify data in the parent blob.  The parent data is not
 141  * expected to be modified, and will result in undefined behavior if it
 142  * is.
 143  *
 144  * Makes @parent immutable.
 145  *
 146  * Return value: New blob, or the empty blob if something failed or if
 147  * @length is zero or @offset is beyond the end of @parent's data.  Destroy
 148  * with hb_blob_destroy().
 149  *
 150  * Since: 1.0
 151  **/
 152 hb_blob_t *
 153 hb_blob_create_sub_blob (hb_blob_t    *parent,
 154                          unsigned int  offset,
 155                          unsigned int  length)
 156 {
 157   hb_blob_t *blob;
 158
 159   if (!length || offset >= parent->length)
 160     return hb_blob_get_empty ();
 161
 162   hb_blob_make_immutable (parent);
 163
 164   blob = hb_blob_create (parent->data + offset,
 165                          MIN (length, parent->length - offset),
 166                          HB_MEMORY_MODE_READONLY,
 167                          hb_blob_reference (parent),
 168                          (hb_destroy_func_t) hb_blob_destroy);
 169
 170   return blob;
 171 }
 172
 173 /**
 174  * hb_blob_get_empty:
 175  *
 176  * Returns the singleton empty blob.
 177  *
 178  * See TODO:link object types for more information.
 179  *
 180  * Return value: (transfer full): the empty blob.
 181  *
 182  * Since: 1.0
 183  **/
 184 hb_blob_t *
 185 hb_blob_get_empty (void)
 186 {
 187   static const hb_blob_t _hb_blob_nil = {
 188     HB_OBJECT_HEADER_STATIC,
 189
 190     true, /* immutable */
 191
 192     NULL, /* data */
 193     0, /* length */
 194     HB_MEMORY_MODE_READONLY, /* mode */
 195
 196     NULL, /* user_data */
 197     NULL  /* destroy */
 198   };
 199
 200   return const_cast<hb_blob_t *> (&_hb_blob_nil);
 201 }
 202
 203 /**
 204  * hb_blob_reference: (skip)
 205  * @blob: a blob.
 206  *
 207  * Increases the reference count on @blob.
 208  *
 209  * See TODO:link object types for more information.
 210  *
 211  * Return value: @blob.
 212  *
 213  * Since: 1.0
 214  **/
 215 hb_blob_t *
 216 hb_blob_reference (hb_blob_t *blob)
 217 {
 218   return hb_object_reference (blob);
 219 }
 220
 221 /**
 222  * hb_blob_destroy: (skip)
 223  * @blob: a blob.
 224  *
 225  * Descreases the reference count on @blob, and if it reaches zero, destroys
 226  * @blob, freeing all memory, possibly calling the destroy-callback the blob
 227  * was created for if it has not been called already.
 228  *
 229  * See TODO:link object types for more information.
 230  *
 231  * Since: 1.0
 232  **/
 233 void
 234 hb_blob_destroy (hb_blob_t *blob)
 235 {
 236   if (!hb_object_destroy (blob)) return;
 237
 238   _hb_blob_destroy_user_data (blob);
 239
 240   free (blob);
 241 }
 242
 243 /**
 244  * hb_blob_set_user_data: (skip)
 245  * @blob: a blob.
 246  * @key: key for data to set.
 247  * @data: data to set.
 248  * @destroy: callback to call when @data is not needed anymore.
 249  * @replace: whether to replace an existing data with the same key.
 250  *
 251  * Return value:
 252  *
 253  * Since: 1.0
 254  **/
 255 hb_bool_t
 256 hb_blob_set_user_data (hb_blob_t          *blob,
 257                        hb_user_data_key_t *key,
 258                        void *              data,
 259                        hb_destroy_func_t   destroy,
 260                        hb_bool_t           replace)
 261 {
 262   return hb_object_set_user_data (blob, key, data, destroy, replace);
 263 }
 264
 265 /**
 266  * hb_blob_get_user_data: (skip)
 267  * @blob: a blob.
 268  * @key: key for data to get.
 269  *
 270  *
 271  *
 272  * Return value: (transfer none):
 273  *
 274  * Since: 1.0
 275  **/
 276 void *
 277 hb_blob_get_user_data (hb_blob_t          *blob,
 278                        hb_user_data_key_t *key)
 279 {
 280   return hb_object_get_user_data (blob, key);
 281 }
 282
 283
 284 /**
 285  * hb_blob_make_immutable:
 286  * @blob: a blob.
 287  *
 288  *
 289  *
 290  * Since: 1.0
 291  **/
 292 void
 293 hb_blob_make_immutable (hb_blob_t *blob)
 294 {
 295   if (hb_object_is_inert (blob))
 296     return;
 297
 298   blob->immutable = true;
 299 }
 300
 301 /**
 302  * hb_blob_is_immutable:
 303  * @blob: a blob.
 304  *
 305  *
 306  *
 307  * Return value: TODO
 308  *
 309  * Since: 1.0
 310  **/
 311 hb_bool_t
 312 hb_blob_is_immutable (hb_blob_t *blob)
 313 {
 314   return blob->immutable;
 315 }
 316
 317
 318 /**
 319  * hb_blob_get_length:
 320  * @blob: a blob.
 321  *
 322  *
 323  *
 324  * Return value: the length of blob data in bytes.
 325  *
 326  * Since: 1.0
 327  **/
 328 unsigned int
 329 hb_blob_get_length (hb_blob_t *blob)
 330 {
 331   return blob->length;
 332 }
 333
 334 /**
 335  * hb_blob_get_data:
 336  * @blob: a blob.
 337  * @length: (out):
 338  *
 339  *
 340  *
 341  * Returns: (transfer none) (array length=length):
 342  *
 343  * Since: 1.0
 344  **/
 345 const char *
 346 hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
 347 {
 348   if (length)
 349     *length = blob->length;
 350
 351   return blob->data;
 352 }
 353
 354 /**
 355  * hb_blob_get_data_writable:
 356  * @blob: a blob.
 357  * @length: (out): output length of the writable data.
 358  *
 359  * Tries to make blob data writable (possibly copying it) and
 360  * return pointer to data.
 361  *
 362  * Fails if blob has been made immutable, or if memory allocation
 363  * fails.
 364  *
 365  * Returns: (transfer none) (array length=length): Writable blob data,
 366  * or %NULL if failed.
 367  *
 368  * Since: 1.0
 369  **/
 370 char *
 371 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
 372 {
 373   if (!_try_writable (blob)) {
 374     if (length)
 375       *length = 0;
 376
 377     return NULL;
 378   }
 379
 380   if (length)
 381     *length = blob->length;
 382
 383   return const_cast<char *> (blob->data);
 384 }
 385
 386
 387 static hb_bool_t
 388 _try_make_writable_inplace_unix (hb_blob_t *blob)
 389 {
 390 #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
 391   uintptr_t pagesize = -1, mask, length;
 392   const char *addr;
 393
 394 #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
 395   pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
 396 #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
 397   pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
 398 #elif defined(HAVE_GETPAGESIZE)
 399   pagesize = (uintptr_t) getpagesize ();
 400 #endif
 401
 402   if ((uintptr_t) -1L == pagesize) {
 403     DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
 404     return false;
 405   }
 406   DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
 407
 408   mask = ~(pagesize-1);
 409   addr = (const char *) (((uintptr_t) blob->data) & mask);
 410   length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask)  - addr;
 411   DEBUG_MSG_FUNC (BLOB, blob,
 412                   "calling mprotect on [%p..%p] (%lu bytes)",
 413                   addr, addr+length, (unsigned long) length);
 414   if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
 415     DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
 416     return false;
 417   }
 418
 419   blob->mode = HB_MEMORY_MODE_WRITABLE;
 420
 421   DEBUG_MSG_FUNC (BLOB, blob,
 422                   "successfully made [%p..%p] (%lu bytes) writable\n",
 423                   addr, addr+length, (unsigned long) length);
 424   return true;
 425 #else
 426   return false;
 427 #endif
 428 }
 429
 430 static bool
 431 _try_writable_inplace (hb_blob_t *blob)
 432 {
 433   DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
 434
 435   if (_try_make_writable_inplace_unix (blob))
 436     return true;
 437
 438   DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
 439
 440   /* Failed to make writable inplace, mark that */
 441   blob->mode = HB_MEMORY_MODE_READONLY;
 442   return false;
 443 }
 444
 445 static bool
 446 _try_writable (hb_blob_t *blob)
 447 {
 448   if (blob->immutable)
 449     return false;
 450
 451   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
 452     return true;
 453
 454   if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
 455     return true;
 456
 457   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
 458     return true;
 459
 460
 461   DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
 462
 463   char *new_data;
 464
 465   new_data = (char *) malloc (blob->length);
 466   if (unlikely (!new_data))
 467     return false;
 468
 469   DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
 470
 471   memcpy (new_data, blob->data, blob->length);
 472   _hb_blob_destroy_user_data (blob);
 473   blob->mode = HB_MEMORY_MODE_WRITABLE;
 474   blob->data = new_data;
 475   blob->user_data = new_data;
 476   blob->destroy = free;
 477
 478   return true;
 479 }