| /* Copyright (c) 2013 The Chromium OS Authors. All rights reserved. |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| /* |
| * Helper functions/wrappers for memory allocations, manipulation and |
| * comparison. |
| */ |
| |
| #ifndef VBOOT_FIRMWARE_LIB_STATEFUL_UTIL_H_ |
| #define VBOOT_FIRMWARE_LIB_STATEFUL_UTIL_H_ |
| |
| #include "sysincludes.h" |
| |
| /* Track remaining data to be read in a buffer. */ |
| typedef struct MemcpyState { |
| uint8_t *remaining_buf; |
| uint64_t remaining_len; /* Remaining length of the buffer. */ |
| uint8_t overrun; /* Flag set to 1 when an overrun occurs. */ |
| } MemcpyState; |
| |
| /** |
| * Initialize a stateful buffer struct to point to the buffer, with the |
| * specified remaining length in bytes. |
| */ |
| void StatefulInit(MemcpyState *state, void *buf, uint64_t len); |
| |
| /** |
| * Skip [len] bytes only if there's enough data to skip according to [state]. |
| * |
| * On success, return a meaningless but non-NULL pointer and updates [state]. |
| * On failure, return NULL, set state->overrun to 1. |
| * |
| * Useful for iterating through a binary blob to populate a struct. After the |
| * first failure (buffer overrun), successive calls will always fail. |
| */ |
| void *StatefulSkip(MemcpyState *state, uint64_t len); |
| |
| /** |
| * Copy [len] bytes into [dst] only if there's enough data to read according |
| * to [state]. |
| * |
| * On success, return [dst] and update [state]. |
| * On failure, return NULL, set state->overrun to 1. |
| * |
| * Useful for iterating through a binary blob to populate a struct. After the |
| * first failure (buffer overrun), successive calls will always fail. |
| */ |
| void *StatefulMemcpy(MemcpyState *state, void *dst, uint64_t len); |
| |
| /** |
| * Like StatefulMemcpy() but copies in the opposite direction, populating |
| * data from [src] into the buffer encapsulated in state [state]. |
| * |
| * On success, return [src] and update [state]. |
| * On failure, return NULL, set state->overrun to 1. |
| * |
| * Useful for iterating through a structure to populate a binary blob. After the |
| * first failure (buffer overrun), successive calls will always fail. |
| */ |
| const void *StatefulMemcpy_r(MemcpyState *state, const void *src, uint64_t len); |
| |
| /** |
| * Like StatefulMemcpy_r() but fills a portion of the encapsulated buffer with |
| * a constant value. |
| * |
| * On success, return a meaningless but non-NULL pointer and updates [state]. |
| * On failure, return NULL, set state->overrun to 1. |
| * |
| * After the first failure (buffer overrun), successive calls will always fail. |
| */ |
| const void *StatefulMemset_r(MemcpyState *state, const uint8_t val, |
| uint64_t len); |
| |
| #endif |