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 #if defined(_POSIX_C_SOURCE)
  29 #undef _POSIX_C_SOURCE
  30 #endif
  31 #define _POSIX_C_SOURCE 199309L
  32
  33 #include "hb-private.hh"
  34
  35 #include "hb-blob.h"
  36 #include "hb-object-private.hh"
  37
  38 #ifdef HAVE_SYS_MMAN_H
  39 #ifdef HAVE_UNISTD_H
  40 #include <unistd.h>
  41 #endif /* HAVE_UNISTD_H */
  42 #include <sys/mman.h>
  43 #endif /* HAVE_SYS_MMAN_H */
  44
  45 #include <stdio.h>
  46 #include <errno.h>
  47
  48
  49
  50 #ifndef HB_DEBUG_BLOB
  51 #define HB_DEBUG_BLOB (HB_DEBUG+0)
  52 #endif
  53
  54
  55 struct hb_blob_t {
  56   hb_object_header_t header;
  57   ASSERT_POD ();
  58
  59   bool immutable;
  60
  61   const char *data;
  62   unsigned int length;
  63   hb_memory_mode_t mode;
  64
  65   void *user_data;
  66   hb_destroy_func_t destroy;
  67 };
  68
  69
  70 static bool _try_writable (hb_blob_t *blob);
  71
  72 static void
  73 _hb_blob_destroy_user_data (hb_blob_t *blob)
  74 {
  75   if (blob->destroy) {
  76     blob->destroy (blob->user_data);
  77     blob->user_data = NULL;
  78     blob->destroy = NULL;
  79   }
  80 }
  81
  82 hb_blob_t *
  83 hb_blob_create (const char        *data,
  84                 unsigned int       length,
  85                 hb_memory_mode_t   mode,
  86                 void              *user_data,
  87                 hb_destroy_func_t  destroy)
  88 {
  89   hb_blob_t *blob;
  90
  91   if (!length || !(blob = hb_object_create<hb_blob_t> ())) {
  92     if (destroy)
  93       destroy (user_data);
  94     return hb_blob_get_empty ();
  95   }
  96
  97   blob->data = data;
  98   blob->length = length;
  99   blob->mode = mode;
 100
 101   blob->user_data = user_data;
 102   blob->destroy = destroy;
 103
 104   if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
 105     blob->mode = HB_MEMORY_MODE_READONLY;
 106     if (!_try_writable (blob)) {
 107       hb_blob_destroy (blob);
 108       return hb_blob_get_empty ();
 109     }
 110   }
 111
 112   return blob;
 113 }
 114
 115 hb_blob_t *
 116 hb_blob_create_sub_blob (hb_blob_t    *parent,
 117                          unsigned int  offset,
 118                          unsigned int  length)
 119 {
 120   hb_blob_t *blob;
 121
 122   if (!length || offset >= parent->length)
 123     return hb_blob_get_empty ();
 124
 125   hb_blob_make_immutable (parent);
 126
 127   blob = hb_blob_create (parent->data + offset,
 128                          MIN (length, parent->length - offset),
 129                          HB_MEMORY_MODE_READONLY,
 130                          hb_blob_reference (parent),
 131                          (hb_destroy_func_t) hb_blob_destroy);
 132
 133   return blob;
 134 }
 135
 136 hb_blob_t *
 137 hb_blob_get_empty (void)
 138 {
 139   static const hb_blob_t _hb_blob_nil = {
 140     HB_OBJECT_HEADER_STATIC,
 141
 142     true, /* immutable */
 143
 144     NULL, /* data */
 145     0, /* length */
 146     HB_MEMORY_MODE_READONLY, /* mode */
 147
 148     NULL, /* user_data */
 149     NULL  /* destroy */
 150   };
 151
 152   return const_cast<hb_blob_t *> (&_hb_blob_nil);
 153 }
 154
 155 hb_blob_t *
 156 hb_blob_reference (hb_blob_t *blob)
 157 {
 158   return hb_object_reference (blob);
 159 }
 160
 161 void
 162 hb_blob_destroy (hb_blob_t *blob)
 163 {
 164   if (!hb_object_destroy (blob)) return;
 165
 166   _hb_blob_destroy_user_data (blob);
 167
 168   free (blob);
 169 }
 170
 171 hb_bool_t
 172 hb_blob_set_user_data (hb_blob_t          *blob,
 173                        hb_user_data_key_t *key,
 174                        void *              data,
 175                        hb_destroy_func_t   destroy,
 176                        hb_bool_t           replace)
 177 {
 178   return hb_object_set_user_data (blob, key, data, destroy, replace);
 179 }
 180
 181 void *
 182 hb_blob_get_user_data (hb_blob_t          *blob,
 183                        hb_user_data_key_t *key)
 184 {
 185   return hb_object_get_user_data (blob, key);
 186 }
 187
 188
 189 void
 190 hb_blob_make_immutable (hb_blob_t *blob)
 191 {
 192   if (hb_object_is_inert (blob))
 193     return;
 194
 195   blob->immutable = true;
 196 }
 197
 198 hb_bool_t
 199 hb_blob_is_immutable (hb_blob_t *blob)
 200 {
 201   return blob->immutable;
 202 }
 203
 204
 205 unsigned int
 206 hb_blob_get_length (hb_blob_t *blob)
 207 {
 208   return blob->length;
 209 }
 210
 211 const char *
 212 hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
 213 {
 214   if (length)
 215     *length = blob->length;
 216
 217   return blob->data;
 218 }
 219
 220 char *
 221 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
 222 {
 223   if (!_try_writable (blob)) {
 224     if (length)
 225       *length = 0;
 226
 227     return NULL;
 228   }
 229
 230   if (length)
 231     *length = blob->length;
 232
 233   return const_cast<char *> (blob->data);
 234 }
 235
 236
 237 static hb_bool_t
 238 _try_make_writable_inplace_unix (hb_blob_t *blob)
 239 {
 240 #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
 241   uintptr_t pagesize = -1, mask, length;
 242   const char *addr;
 243
 244 #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
 245   pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
 246 #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
 247   pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
 248 #elif defined(HAVE_GETPAGESIZE)
 249   pagesize = (uintptr_t) getpagesize ();
 250 #endif
 251
 252   if ((uintptr_t) -1L == pagesize) {
 253     DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
 254     return false;
 255   }
 256   DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
 257
 258   mask = ~(pagesize-1);
 259   addr = (const char *) (((uintptr_t) blob->data) & mask);
 260   length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask)  - addr;
 261   DEBUG_MSG_FUNC (BLOB, blob,
 262                   "calling mprotect on [%p..%p] (%lu bytes)",
 263                   addr, addr+length, (unsigned long) length);
 264   if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
 265     DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
 266     return false;
 267   }
 268
 269   blob->mode = HB_MEMORY_MODE_WRITABLE;
 270
 271   DEBUG_MSG_FUNC (BLOB, blob,
 272                   "successfully made [%p..%p] (%lu bytes) writable\n",
 273                   addr, addr+length, (unsigned long) length);
 274   return true;
 275 #else
 276   return false;
 277 #endif
 278 }
 279
 280 static bool
 281 _try_writable_inplace (hb_blob_t *blob)
 282 {
 283   DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
 284
 285   if (_try_make_writable_inplace_unix (blob))
 286     return true;
 287
 288   DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
 289
 290   /* Failed to make writable inplace, mark that */
 291   blob->mode = HB_MEMORY_MODE_READONLY;
 292   return false;
 293 }
 294
 295 static bool
 296 _try_writable (hb_blob_t *blob)
 297 {
 298   if (blob->immutable)
 299     return false;
 300
 301   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
 302     return true;
 303
 304   if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
 305     return true;
 306
 307   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
 308     return true;
 309
 310
 311   DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
 312
 313   char *new_data;
 314
 315   new_data = (char *) malloc (blob->length);
 316   if (unlikely (!new_data))
 317     return false;
 318
 319   DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
 320
 321   memcpy (new_data, blob->data, blob->length);
 322   _hb_blob_destroy_user_data (blob);
 323   blob->mode = HB_MEMORY_MODE_WRITABLE;
 324   blob->data = new_data;
 325   blob->user_data = new_data;
 326   blob->destroy = free;
 327
 328   return true;
 329 }
 330
 331