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/*
* Copyright © 2014 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <string.h>
#include "blob.h"
#include "u_math.h"
#ifdef HAVE_VALGRIND
#include <valgrind.h>
#include <memcheck.h>
#define VG(x) x
#else
#define VG(x)
#endif
#define BLOB_INITIAL_SIZE 4096
/* Ensure that \blob will be able to fit an additional object of size
* \additional. The growing (if any) will occur by doubling the existing
* allocation.
*/
static bool
grow_to_fit(struct blob *blob, size_t additional)
{
size_t to_allocate;
uint8_t *new_data;
if (blob->out_of_memory)
return false;
if (blob->size + additional <= blob->allocated)
return true;
if (blob->fixed_allocation) {
blob->out_of_memory = true;
return false;
}
if (blob->allocated == 0)
to_allocate = BLOB_INITIAL_SIZE;
else
to_allocate = blob->allocated * 2;
to_allocate = MAX2(to_allocate, blob->allocated + additional);
new_data = realloc(blob->data, to_allocate);
if (new_data == NULL) {
blob->out_of_memory = true;
return false;
}
blob->data = new_data;
blob->allocated = to_allocate;
return true;
}
/* Align the blob->size so that reading or writing a value at (blob->data +
* blob->size) will result in an access aligned to a granularity of \alignment
* bytes.
*
* \return True unless allocation fails
*/
static bool
align_blob(struct blob *blob, size_t alignment)
{
const size_t new_size = align64(blob->size, alignment);
if (blob->size < new_size) {
if (!grow_to_fit(blob, new_size - blob->size))
return false;
if (blob->data)
memset(blob->data + blob->size, 0, new_size - blob->size);
blob->size = new_size;
}
return true;
}
static void
align_blob_reader(struct blob_reader *blob, size_t alignment)
{
blob->current = blob->data + align64(blob->current - blob->data, alignment);
}
void
blob_init(struct blob *blob)
{
blob->data = NULL;
blob->allocated = 0;
blob->size = 0;
blob->fixed_allocation = false;
blob->out_of_memory = false;
}
void
blob_init_fixed(struct blob *blob, void *data, size_t size)
{
blob->data = data;
blob->allocated = size;
blob->size = 0;
blob->fixed_allocation = true;
blob->out_of_memory = false;
}
void
blob_finish_get_buffer(struct blob *blob, void **buffer, size_t *size)
{
*buffer = blob->data;
*size = blob->size;
blob->data = NULL;
/* Trim the buffer. */
*buffer = realloc(*buffer, *size);
}
bool
blob_overwrite_bytes(struct blob *blob,
size_t offset,
const void *bytes,
size_t to_write)
{
/* Detect an attempt to overwrite data out of bounds. */
if (offset + to_write < offset || blob->size < offset + to_write)
return false;
VG(VALGRIND_CHECK_MEM_IS_DEFINED(bytes, to_write));
if (blob->data)
memcpy(blob->data + offset, bytes, to_write);
return true;
}
bool
blob_write_bytes(struct blob *blob, const void *bytes, size_t to_write)
{
if (! grow_to_fit(blob, to_write))
return false;
VG(VALGRIND_CHECK_MEM_IS_DEFINED(bytes, to_write));
if (blob->data && to_write > 0)
memcpy(blob->data + blob->size, bytes, to_write);
blob->size += to_write;
return true;
}
intptr_t
blob_reserve_bytes(struct blob *blob, size_t to_write)
{
intptr_t ret;
if (! grow_to_fit (blob, to_write))
return -1;
ret = blob->size;
blob->size += to_write;
return ret;
}
intptr_t
blob_reserve_uint32(struct blob *blob)
{
align_blob(blob, sizeof(uint32_t));
return blob_reserve_bytes(blob, sizeof(uint32_t));
}
intptr_t
blob_reserve_intptr(struct blob *blob)
{
align_blob(blob, sizeof(intptr_t));
return blob_reserve_bytes(blob, sizeof(intptr_t));
}
#define BLOB_WRITE_TYPE(name, type) \
bool \
name(struct blob *blob, type value) \
{ \
align_blob(blob, sizeof(value)); \
return blob_write_bytes(blob, &value, sizeof(value)); \
}
BLOB_WRITE_TYPE(blob_write_uint8, uint8_t)
BLOB_WRITE_TYPE(blob_write_uint16, uint16_t)
BLOB_WRITE_TYPE(blob_write_uint32, uint32_t)
BLOB_WRITE_TYPE(blob_write_uint64, uint64_t)
BLOB_WRITE_TYPE(blob_write_intptr, intptr_t)
#define ASSERT_ALIGNED(_offset, _align) \
assert(align64((_offset), (_align)) == (_offset))
bool
blob_overwrite_uint8 (struct blob *blob,
size_t offset,
uint8_t value)
{
ASSERT_ALIGNED(offset, sizeof(value));
return blob_overwrite_bytes(blob, offset, &value, sizeof(value));
}
bool
blob_overwrite_uint32 (struct blob *blob,
size_t offset,
uint32_t value)
{
ASSERT_ALIGNED(offset, sizeof(value));
return blob_overwrite_bytes(blob, offset, &value, sizeof(value));
}
bool
blob_overwrite_intptr (struct blob *blob,
size_t offset,
intptr_t value)
{
ASSERT_ALIGNED(offset, sizeof(value));
return blob_overwrite_bytes(blob, offset, &value, sizeof(value));
}
bool
blob_write_string(struct blob *blob, const char *str)
{
return blob_write_bytes(blob, str, strlen(str) + 1);
}
void
blob_reader_init(struct blob_reader *blob, const void *data, size_t size)
{
blob->data = data;
blob->end = blob->data + size;
blob->current = data;
blob->overrun = false;
}
/* Check that an object of size \size can be read from this blob.
*
* If not, set blob->overrun to indicate that we attempted to read too far.
*/
static bool
ensure_can_read(struct blob_reader *blob, size_t size)
{
if (blob->overrun)
return false;
if (blob->current <= blob->end && blob->end - blob->current >= size)
return true;
blob->overrun = true;
return false;
}
const void *
blob_read_bytes(struct blob_reader *blob, size_t size)
{
const void *ret;
if (! ensure_can_read (blob, size))
return NULL;
ret = blob->current;
blob->current += size;
return ret;
}
void
blob_copy_bytes(struct blob_reader *blob, void *dest, size_t size)
{
const void *bytes;
bytes = blob_read_bytes(blob, size);
if (bytes == NULL || size == 0)
return;
memcpy(dest, bytes, size);
}
void
blob_skip_bytes(struct blob_reader *blob, size_t size)
{
if (ensure_can_read (blob, size))
blob->current += size;
}
/* These next three read functions have identical form. If we add any beyond
* these first three we should probably switch to generating these with a
* preprocessor macro.
*/
#define BLOB_READ_TYPE(name, type) \
type \
name(struct blob_reader *blob) \
{ \
type ret; \
int size = sizeof(ret); \
align_blob_reader(blob, size); \
if (! ensure_can_read(blob, size)) \
return 0; \
ret = *((type*) blob->current); \
blob->current += size; \
return ret; \
}
BLOB_READ_TYPE(blob_read_uint8, uint8_t)
BLOB_READ_TYPE(blob_read_uint16, uint16_t)
BLOB_READ_TYPE(blob_read_uint32, uint32_t)
BLOB_READ_TYPE(blob_read_uint64, uint64_t)
BLOB_READ_TYPE(blob_read_intptr, intptr_t)
char *
blob_read_string(struct blob_reader *blob)
{
int size;
char *ret;
uint8_t *nul;
/* If we're already at the end, then this is an overrun. */
if (blob->current >= blob->end) {
blob->overrun = true;
return NULL;
}
/* Similarly, if there is no zero byte in the data remaining in this blob,
* we also consider that an overrun.
*/
nul = memchr(blob->current, 0, blob->end - blob->current);
if (nul == NULL) {
blob->overrun = true;
return NULL;
}
size = nul - blob->current + 1;
assert(ensure_can_read(blob, size));
ret = (char *) blob->current;
blob->current += size;
return ret;
}