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-rw-r--r--src/util/blob.c391
1 files changed, 391 insertions, 0 deletions
diff --git a/src/util/blob.c b/src/util/blob.c
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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 "main/macros.h"
+#include "blob.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 = ALIGN(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 + ALIGN(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;
+}
+
+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)
+ 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));
+}
+
+bool
+blob_write_uint32(struct blob *blob, uint32_t value)
+{
+ align_blob(blob, sizeof(value));
+
+ return blob_write_bytes(blob, &value, sizeof(value));
+}
+
+#define ASSERT_ALIGNED(_offset, _align) \
+ assert(ALIGN((_offset), (_align)) == (_offset))
+
+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_write_uint64(struct blob *blob, uint64_t value)
+{
+ align_blob(blob, sizeof(value));
+
+ return blob_write_bytes(blob, &value, sizeof(value));
+}
+
+bool
+blob_write_intptr(struct blob *blob, intptr_t value)
+{
+ align_blob(blob, sizeof(value));
+
+ return blob_write_bytes(blob, &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)
+ 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.
+*/
+uint32_t
+blob_read_uint32(struct blob_reader *blob)
+{
+ uint32_t ret;
+ int size = sizeof(ret);
+
+ align_blob_reader(blob, size);
+
+ if (! ensure_can_read(blob, size))
+ return 0;
+
+ ret = *((uint32_t*) blob->current);
+
+ blob->current += size;
+
+ return ret;
+}
+
+uint64_t
+blob_read_uint64(struct blob_reader *blob)
+{
+ uint64_t ret;
+ int size = sizeof(ret);
+
+ align_blob_reader(blob, size);
+
+ if (! ensure_can_read(blob, size))
+ return 0;
+
+ ret = *((uint64_t*) blob->current);
+
+ blob->current += size;
+
+ return ret;
+}
+
+intptr_t
+blob_read_intptr(struct blob_reader *blob)
+{
+ intptr_t ret;
+ int size = sizeof(ret);
+
+ align_blob_reader(blob, size);
+
+ if (! ensure_can_read(blob, size))
+ return 0;
+
+ ret = *((intptr_t *) blob->current);
+
+ blob->current += size;
+
+ return ret;
+}
+
+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;
+}
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