/*
* Copyright © 2009 Red Hat, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Red Hat Author(s): Behdad Esfahbod
*/
/* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE 199309L
#endif
#include "hb-private.hh"
#include "hb-object-private.hh"
#ifdef HAVE_SYS_MMAN_H
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <sys/mman.h>
#endif /* HAVE_SYS_MMAN_H */
#include <stdio.h>
#include <errno.h>
#ifndef HB_DEBUG_BLOB
#define HB_DEBUG_BLOB (HB_DEBUG+0)
#endif
struct hb_blob_t {
hb_object_header_t header;
ASSERT_POD ();
bool immutable;
const char *data;
unsigned int length;
hb_memory_mode_t mode;
void *user_data;
hb_destroy_func_t destroy;
};
static bool _try_writable (hb_blob_t *blob);
static void
_hb_blob_destroy_user_data (hb_blob_t *blob)
{
if (blob->destroy) {
blob->destroy (blob->user_data);
blob->user_data = NULL;
blob->destroy = NULL;
}
}
/**
* hb_blob_create: (skip)
* @data: Pointer to blob data.
* @length: Length of @data in bytes.
* @mode: Memory mode for @data.
* @user_data: Data parameter to pass to @destroy.
* @destroy: Callback to call when @data is not needed anymore.
*
* Creates a new "blob" object wrapping @data. The @mode parameter is used
* to negotiate ownership and lifecycle of @data.
*
* Return value: New blob, or the empty blob if something failed or if @length is
* zero. Destroy with hb_blob_destroy().
*
* Since: 0.9.2
**/
hb_blob_t *
hb_blob_create (const char *data,
unsigned int length,
hb_memory_mode_t mode,
void *user_data,
hb_destroy_func_t destroy)
{
hb_blob_t *blob;
if (!length ||
length >= 1u << 31 ||
!(blob = hb_object_create<hb_blob_t> ())) {
if (destroy)
destroy (user_data);
return hb_blob_get_empty ();
}
blob->data = data;
blob->length = length;
blob->mode = mode;
blob->user_data = user_data;
blob->destroy = destroy;
if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
blob->mode = HB_MEMORY_MODE_READONLY;
if (!_try_writable (blob)) {
hb_blob_destroy (blob);
return hb_blob_get_empty ();
}
}
return blob;
}
/**
* hb_blob_create_sub_blob:
* @parent: Parent blob.
* @offset: Start offset of sub-blob within @parent, in bytes.
* @length: Length of sub-blob.
*
* Returns a blob that represents a range of bytes in @parent. The new
* blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
* will never modify data in the parent blob. The parent data is not
* expected to be modified, and will result in undefined behavior if it
* is.
*
* Makes @parent immutable.
*
* Return value: New blob, or the empty blob if something failed or if
* @length is zero or @offset is beyond the end of @parent's data. Destroy
* with hb_blob_destroy().
*
* Since: 0.9.2
**/
hb_blob_t *
hb_blob_create_sub_blob (hb_blob_t *parent,
unsigned int offset,
unsigned int length)
{
hb_blob_t *blob;
if (!length || offset >= parent->length)
return hb_blob_get_empty ();
hb_blob_make_immutable (parent);
blob = hb_blob_create (parent->data + offset,
MIN (length, parent->length - offset),
HB_MEMORY_MODE_READONLY,
hb_blob_reference (parent),
(hb_destroy_func_t) hb_blob_destroy);
return blob;
}
/**
* hb_blob_get_empty:
*
* Returns the singleton empty blob.
*
* See TODO:link object types for more information.
*
* Return value: (transfer full): the empty blob.
*
* Since: 0.9.2
**/
hb_blob_t *
hb_blob_get_empty (void)
{
static const hb_blob_t _hb_blob_nil = {
HB_OBJECT_HEADER_STATIC,
true, /* immutable */
NULL, /* data */
0, /* length */
HB_MEMORY_MODE_READONLY, /* mode */
NULL, /* user_data */
NULL /* destroy */
};
return const_cast<hb_blob_t *> (&_hb_blob_nil);
}
/**
* hb_blob_reference: (skip)
* @blob: a blob.
*
* Increases the reference count on @blob.
*
* See TODO:link object types for more information.
*
* Return value: @blob.
*
* Since: 0.9.2
**/
hb_blob_t *
hb_blob_reference (hb_blob_t *blob)
{
return hb_object_reference (blob);
}
/**
* hb_blob_destroy: (skip)
* @blob: a blob.
*
* Descreases the reference count on @blob, and if it reaches zero, destroys
* @blob, freeing all memory, possibly calling the destroy-callback the blob
* was created for if it has not been called already.
*
* See TODO:link object types for more information.
*
* Since: 0.9.2
**/
void
hb_blob_destroy (hb_blob_t *blob)
{
if (!hb_object_destroy (blob)) return;
_hb_blob_destroy_user_data (blob);
free (blob);
}
/**
* hb_blob_set_user_data: (skip)
* @blob: a blob.
* @key: key for data to set.
* @data: data to set.
* @destroy: callback to call when @data is not needed anymore.
* @replace: whether to replace an existing data with the same key.
*
* Return value:
*
* Since: 0.9.2
**/
hb_bool_t
hb_blob_set_user_data (hb_blob_t *blob,
hb_user_data_key_t *key,
void * data,
hb_destroy_func_t destroy,
hb_bool_t replace)
{
return hb_object_set_user_data (blob, key, data, destroy, replace);
}
/**
* hb_blob_get_user_data: (skip)
* @blob: a blob.
* @key: key for data to get.
*
*
*
* Return value: (transfer none):
*
* Since: 0.9.2
**/
void *
hb_blob_get_user_data (hb_blob_t *blob,
hb_user_data_key_t *key)
{
return hb_object_get_user_data (blob, key);
}
/**
* hb_blob_make_immutable:
* @blob: a blob.
*
*
*
* Since: 0.9.2
**/
void
hb_blob_make_immutable (hb_blob_t *blob)
{
if (hb_object_is_inert (blob))
return;
blob->immutable = true;
}
/**
* hb_blob_is_immutable:
* @blob: a blob.
*
*
*
* Return value: TODO
*
* Since: 0.9.2
**/
hb_bool_t
hb_blob_is_immutable (hb_blob_t *blob)
{
return blob->immutable;
}
/**
* hb_blob_get_length:
* @blob: a blob.
*
*
*
* Return value: the length of blob data in bytes.
*
* Since: 0.9.2
**/
unsigned int
hb_blob_get_length (hb_blob_t *blob)
{
return blob->length;
}
/**
* hb_blob_get_data:
* @blob: a blob.
* @length: (out):
*
*
*
* Returns: (transfer none) (array length=length):
*
* Since: 0.9.2
**/
const char *
hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
{
if (length)
*length = blob->length;
return blob->data;
}
/**
* hb_blob_get_data_writable:
* @blob: a blob.
* @length: (out): output length of the writable data.
*
* Tries to make blob data writable (possibly copying it) and
* return pointer to data.
*
* Fails if blob has been made immutable, or if memory allocation
* fails.
*
* Returns: (transfer none) (array length=length): Writable blob data,
* or %NULL if failed.
*
* Since: 0.9.2
**/
char *
hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
{
if (!_try_writable (blob)) {
if (length)
*length = 0;
return NULL;
}
if (length)
*length = blob->length;
return const_cast<char *> (blob->data);
}
static hb_bool_t
_try_make_writable_inplace_unix (hb_blob_t *blob)
{
#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
uintptr_t pagesize = -1, mask, length;
const char *addr;
#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
#elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
#elif defined(HAVE_GETPAGESIZE)
pagesize = (uintptr_t) getpagesize ();
#endif
if ((uintptr_t) -1L == pagesize) {
DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
return false;
}
DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
mask = ~(pagesize-1);
addr = (const char *) (((uintptr_t) blob->data) & mask);
length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask) - addr;
DEBUG_MSG_FUNC (BLOB, blob,
"calling mprotect on [%p..%p] (%lu bytes)",
addr, addr+length, (unsigned long) length);
if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
return false;
}
blob->mode = HB_MEMORY_MODE_WRITABLE;
DEBUG_MSG_FUNC (BLOB, blob,
"successfully made [%p..%p] (%lu bytes) writable\n",
addr, addr+length, (unsigned long) length);
return true;
#else
return false;
#endif
}
static bool
_try_writable_inplace (hb_blob_t *blob)
{
DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
if (_try_make_writable_inplace_unix (blob))
return true;
DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
/* Failed to make writable inplace, mark that */
blob->mode = HB_MEMORY_MODE_READONLY;
return false;
}
static bool
_try_writable (hb_blob_t *blob)
{
if (blob->immutable)
return false;
if (blob->mode == HB_MEMORY_MODE_WRITABLE)
return true;
if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
return true;
if (blob->mode == HB_MEMORY_MODE_WRITABLE)
return true;
DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
char *new_data;
new_data = (char *) malloc (blob->length);
if (unlikely (!new_data))
return false;
DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
memcpy (new_data, blob->data, blob->length);
_hb_blob_destroy_user_data (blob);
blob->mode = HB_MEMORY_MODE_WRITABLE;
blob->data = new_data;
blob->user_data = new_data;
blob->destroy = free;
return true;
}