michael@0: /*
michael@0:  * Copyright © 2009  Red Hat, Inc.
michael@0:  *
michael@0:  *  This is part of HarfBuzz, a text shaping library.
michael@0:  *
michael@0:  * Permission is hereby granted, without written agreement and without
michael@0:  * license or royalty fees, to use, copy, modify, and distribute this
michael@0:  * software and its documentation for any purpose, provided that the
michael@0:  * above copyright notice and the following two paragraphs appear in
michael@0:  * all copies of this software.
michael@0:  *
michael@0:  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
michael@0:  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
michael@0:  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
michael@0:  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
michael@0:  * DAMAGE.
michael@0:  *
michael@0:  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
michael@0:  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
michael@0:  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
michael@0:  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
michael@0:  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
michael@0:  *
michael@0:  * Red Hat Author(s): Behdad Esfahbod
michael@0:  */
michael@0: 
michael@0: /* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
michael@0: #define _POSIX_C_SOURCE 199309L
michael@0: 
michael@0: #include "hb-private.hh"
michael@0: 
michael@0: #include "hb-object-private.hh"
michael@0: 
michael@0: #ifdef HAVE_SYS_MMAN_H
michael@0: #ifdef HAVE_UNISTD_H
michael@0: #include <unistd.h>
michael@0: #endif /* HAVE_UNISTD_H */
michael@0: #include <sys/mman.h>
michael@0: #endif /* HAVE_SYS_MMAN_H */
michael@0: 
michael@0: #include <stdio.h>
michael@0: #include <errno.h>
michael@0: 
michael@0: 
michael@0: 
michael@0: #ifndef HB_DEBUG_BLOB
michael@0: #define HB_DEBUG_BLOB (HB_DEBUG+0)
michael@0: #endif
michael@0: 
michael@0: 
michael@0: struct hb_blob_t {
michael@0:   hb_object_header_t header;
michael@0:   ASSERT_POD ();
michael@0: 
michael@0:   bool immutable;
michael@0: 
michael@0:   const char *data;
michael@0:   unsigned int length;
michael@0:   hb_memory_mode_t mode;
michael@0: 
michael@0:   void *user_data;
michael@0:   hb_destroy_func_t destroy;
michael@0: };
michael@0: 
michael@0: 
michael@0: static bool _try_writable (hb_blob_t *blob);
michael@0: 
michael@0: static void
michael@0: _hb_blob_destroy_user_data (hb_blob_t *blob)
michael@0: {
michael@0:   if (blob->destroy) {
michael@0:     blob->destroy (blob->user_data);
michael@0:     blob->user_data = NULL;
michael@0:     blob->destroy = NULL;
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_create: (Xconstructor)
michael@0:  * @data: (array length=length) (closure user_data) (destroy destroy) (scope notified) (transfer none): Pointer to blob data.
michael@0:  * @length: Length of @data in bytes.
michael@0:  * @mode: Memory mode for @data.
michael@0:  * @user_data: Data parameter to pass to @destroy.
michael@0:  * @destroy: Callback to call when @data is not needed anymore.
michael@0:  *
michael@0:  * Creates a new "blob" object wrapping @data.  The @mode parameter is used
michael@0:  * to negotiate ownership and lifecycle of @data.
michael@0:  *
michael@0:  * Return value: New blob, or the empty blob if something failed or if @length is
michael@0:  * zero.  Destroy with hb_blob_destroy().
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: hb_blob_t *
michael@0: hb_blob_create (const char        *data,
michael@0: 		unsigned int       length,
michael@0: 		hb_memory_mode_t   mode,
michael@0: 		void              *user_data,
michael@0: 		hb_destroy_func_t  destroy)
michael@0: {
michael@0:   hb_blob_t *blob;
michael@0: 
michael@0:   if (!length || !(blob = hb_object_create<hb_blob_t> ())) {
michael@0:     if (destroy)
michael@0:       destroy (user_data);
michael@0:     return hb_blob_get_empty ();
michael@0:   }
michael@0: 
michael@0:   blob->data = data;
michael@0:   blob->length = length;
michael@0:   blob->mode = mode;
michael@0: 
michael@0:   blob->user_data = user_data;
michael@0:   blob->destroy = destroy;
michael@0: 
michael@0:   if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
michael@0:     blob->mode = HB_MEMORY_MODE_READONLY;
michael@0:     if (!_try_writable (blob)) {
michael@0:       hb_blob_destroy (blob);
michael@0:       return hb_blob_get_empty ();
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return blob;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_create_sub_blob:
michael@0:  * @parent: Parent blob.
michael@0:  * @offset: Start offset of sub-blob within @parent, in bytes.
michael@0:  * @length: Length of sub-blob.
michael@0:  *
michael@0:  * Returns a blob that represents a range of bytes in @parent.  The new
michael@0:  * blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
michael@0:  * will never modify data in the parent blob.  The parent data is not
michael@0:  * expected to be modified, and will result in undefined behavior if it
michael@0:  * is.
michael@0:  *
michael@0:  * Makes @parent immutable.
michael@0:  *
michael@0:  * Return value: New blob, or the empty blob if something failed or if
michael@0:  * @length is zero or @offset is beyond the end of @parent's data.  Destroy
michael@0:  * with hb_blob_destroy().
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: hb_blob_t *
michael@0: hb_blob_create_sub_blob (hb_blob_t    *parent,
michael@0: 			 unsigned int  offset,
michael@0: 			 unsigned int  length)
michael@0: {
michael@0:   hb_blob_t *blob;
michael@0: 
michael@0:   if (!length || offset >= parent->length)
michael@0:     return hb_blob_get_empty ();
michael@0: 
michael@0:   hb_blob_make_immutable (parent);
michael@0: 
michael@0:   blob = hb_blob_create (parent->data + offset,
michael@0: 			 MIN (length, parent->length - offset),
michael@0: 			 HB_MEMORY_MODE_READONLY,
michael@0: 			 hb_blob_reference (parent),
michael@0: 			 (hb_destroy_func_t) hb_blob_destroy);
michael@0: 
michael@0:   return blob;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_get_empty:
michael@0:  *
michael@0:  * Returns the singleton empty blob.
michael@0:  *
michael@0:  * See TODO:link object types for more information.
michael@0:  *
michael@0:  * Return value: (transfer full): the empty blob.
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: hb_blob_t *
michael@0: hb_blob_get_empty (void)
michael@0: {
michael@0:   static const hb_blob_t _hb_blob_nil = {
michael@0:     HB_OBJECT_HEADER_STATIC,
michael@0: 
michael@0:     true, /* immutable */
michael@0: 
michael@0:     NULL, /* data */
michael@0:     0, /* length */
michael@0:     HB_MEMORY_MODE_READONLY, /* mode */
michael@0: 
michael@0:     NULL, /* user_data */
michael@0:     NULL  /* destroy */
michael@0:   };
michael@0: 
michael@0:   return const_cast<hb_blob_t *> (&_hb_blob_nil);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_reference: (skip)
michael@0:  * @blob: a blob.
michael@0:  *
michael@0:  * Increases the reference count on @blob.
michael@0:  *
michael@0:  * See TODO:link object types for more information.
michael@0:  *
michael@0:  * Return value: @blob.
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: hb_blob_t *
michael@0: hb_blob_reference (hb_blob_t *blob)
michael@0: {
michael@0:   return hb_object_reference (blob);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_destroy: (skip)
michael@0:  * @blob: a blob.
michael@0:  *
michael@0:  * Descreases the reference count on @blob, and if it reaches zero, destroys
michael@0:  * @blob, freeing all memory, possibly calling the destroy-callback the blob
michael@0:  * was created for if it has not been called already.
michael@0:  *
michael@0:  * See TODO:link object types for more information.
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: void
michael@0: hb_blob_destroy (hb_blob_t *blob)
michael@0: {
michael@0:   if (!hb_object_destroy (blob)) return;
michael@0: 
michael@0:   _hb_blob_destroy_user_data (blob);
michael@0: 
michael@0:   free (blob);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_set_user_data: (skip)
michael@0:  * @blob: a blob.
michael@0:  * @key: key for data to set.
michael@0:  * @data: data to set.
michael@0:  * @destroy: callback to call when @data is not needed anymore.
michael@0:  * @replace: whether to replace an existing data with the same key.
michael@0:  *
michael@0:  * Return value: 
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: hb_bool_t
michael@0: hb_blob_set_user_data (hb_blob_t          *blob,
michael@0: 		       hb_user_data_key_t *key,
michael@0: 		       void *              data,
michael@0: 		       hb_destroy_func_t   destroy,
michael@0: 		       hb_bool_t           replace)
michael@0: {
michael@0:   return hb_object_set_user_data (blob, key, data, destroy, replace);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_get_user_data: (skip)
michael@0:  * @blob: a blob.
michael@0:  * @key: key for data to get.
michael@0:  *
michael@0:  * 
michael@0:  *
michael@0:  * Return value: (transfer none): 
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: void *
michael@0: hb_blob_get_user_data (hb_blob_t          *blob,
michael@0: 		       hb_user_data_key_t *key)
michael@0: {
michael@0:   return hb_object_get_user_data (blob, key);
michael@0: }
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * hb_blob_make_immutable:
michael@0:  * @blob: a blob.
michael@0:  *
michael@0:  * 
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: void
michael@0: hb_blob_make_immutable (hb_blob_t *blob)
michael@0: {
michael@0:   if (hb_object_is_inert (blob))
michael@0:     return;
michael@0: 
michael@0:   blob->immutable = true;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_is_immutable:
michael@0:  * @blob: a blob.
michael@0:  *
michael@0:  * 
michael@0:  *
michael@0:  * Return value: TODO
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: hb_bool_t
michael@0: hb_blob_is_immutable (hb_blob_t *blob)
michael@0: {
michael@0:   return blob->immutable;
michael@0: }
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * hb_blob_get_length:
michael@0:  * @blob: a blob.
michael@0:  *
michael@0:  * 
michael@0:  *
michael@0:  * Return value: the length of blob data in bytes.
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: unsigned int
michael@0: hb_blob_get_length (hb_blob_t *blob)
michael@0: {
michael@0:   return blob->length;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_get_data:
michael@0:  * @blob: a blob.
michael@0:  * @length: (out):
michael@0:  *
michael@0:  * 
michael@0:  *
michael@0:  * Returns: (transfer none) (array length=length): 
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: const char *
michael@0: hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
michael@0: {
michael@0:   if (length)
michael@0:     *length = blob->length;
michael@0: 
michael@0:   return blob->data;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * hb_blob_get_data_writable:
michael@0:  * @blob: a blob.
michael@0:  * @length: (out): output length of the writable data.
michael@0:  *
michael@0:  * Tries to make blob data writable (possibly copying it) and
michael@0:  * return pointer to data.
michael@0:  *
michael@0:  * Fails if blob has been made immutable, or if memory allocation
michael@0:  * fails.
michael@0:  *
michael@0:  * Returns: (transfer none) (array length=length): Writable blob data,
michael@0:  * or %NULL if failed.
michael@0:  *
michael@0:  * Since: 1.0
michael@0:  **/
michael@0: char *
michael@0: hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
michael@0: {
michael@0:   if (!_try_writable (blob)) {
michael@0:     if (length)
michael@0:       *length = 0;
michael@0: 
michael@0:     return NULL;
michael@0:   }
michael@0: 
michael@0:   if (length)
michael@0:     *length = blob->length;
michael@0: 
michael@0:   return const_cast<char *> (blob->data);
michael@0: }
michael@0: 
michael@0: 
michael@0: static hb_bool_t
michael@0: _try_make_writable_inplace_unix (hb_blob_t *blob)
michael@0: {
michael@0: #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
michael@0:   uintptr_t pagesize = -1, mask, length;
michael@0:   const char *addr;
michael@0: 
michael@0: #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
michael@0:   pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
michael@0: #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
michael@0:   pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
michael@0: #elif defined(HAVE_GETPAGESIZE)
michael@0:   pagesize = (uintptr_t) getpagesize ();
michael@0: #endif
michael@0: 
michael@0:   if ((uintptr_t) -1L == pagesize) {
michael@0:     DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
michael@0:     return false;
michael@0:   }
michael@0:   DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
michael@0: 
michael@0:   mask = ~(pagesize-1);
michael@0:   addr = (const char *) (((uintptr_t) blob->data) & mask);
michael@0:   length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask)  - addr;
michael@0:   DEBUG_MSG_FUNC (BLOB, blob,
michael@0: 		  "calling mprotect on [%p..%p] (%lu bytes)",
michael@0: 		  addr, addr+length, (unsigned long) length);
michael@0:   if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
michael@0:     DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   blob->mode = HB_MEMORY_MODE_WRITABLE;
michael@0: 
michael@0:   DEBUG_MSG_FUNC (BLOB, blob,
michael@0: 		  "successfully made [%p..%p] (%lu bytes) writable\n",
michael@0: 		  addr, addr+length, (unsigned long) length);
michael@0:   return true;
michael@0: #else
michael@0:   return false;
michael@0: #endif
michael@0: }
michael@0: 
michael@0: static bool
michael@0: _try_writable_inplace (hb_blob_t *blob)
michael@0: {
michael@0:   DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
michael@0: 
michael@0:   if (_try_make_writable_inplace_unix (blob))
michael@0:     return true;
michael@0: 
michael@0:   DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
michael@0: 
michael@0:   /* Failed to make writable inplace, mark that */
michael@0:   blob->mode = HB_MEMORY_MODE_READONLY;
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: static bool
michael@0: _try_writable (hb_blob_t *blob)
michael@0: {
michael@0:   if (blob->immutable)
michael@0:     return false;
michael@0: 
michael@0:   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
michael@0:     return true;
michael@0: 
michael@0:   if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
michael@0:     return true;
michael@0: 
michael@0:   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
michael@0:     return true;
michael@0: 
michael@0: 
michael@0:   DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
michael@0: 
michael@0:   char *new_data;
michael@0: 
michael@0:   new_data = (char *) malloc (blob->length);
michael@0:   if (unlikely (!new_data))
michael@0:     return false;
michael@0: 
michael@0:   DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
michael@0: 
michael@0:   memcpy (new_data, blob->data, blob->length);
michael@0:   _hb_blob_destroy_user_data (blob);
michael@0:   blob->mode = HB_MEMORY_MODE_WRITABLE;
michael@0:   blob->data = new_data;
michael@0:   blob->user_data = new_data;
michael@0:   blob->destroy = free;
michael@0: 
michael@0:   return true;
michael@0: }