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: (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 *
  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 *
 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 *
 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 *
 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
 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
 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 *
 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
 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
 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
 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 *
 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 *
 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
 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
 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
 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 }