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