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1 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved. | 1 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
2 * Use of this source code is governed by a BSD-style license that can be | 2 * Use of this source code is governed by a BSD-style license that can be |
3 * found in the LICENSE file. | 3 * found in the LICENSE file. |
4 */ | 4 */ |
5 | 5 |
6 /* Helper functions/wrappers for memory allocations, manipulation and | 6 /* Helper functions/wrappers for memory allocations, manipulation and |
7 * comparison. | 7 * comparison. |
8 */ | 8 */ |
9 | 9 |
10 #ifndef VBOOT_REFERENCE_UTILITY_H_ | 10 #ifndef VBOOT_REFERENCE_UTILITY_H_ |
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37 | 37 |
38 /* Compare [n] bytes starting at [s1] with [s2] and return 0 if they match, | 38 /* Compare [n] bytes starting at [s1] with [s2] and return 0 if they match, |
39 * 1 if they don't. Time taken to perform the comparison is only dependent on | 39 * 1 if they don't. Time taken to perform the comparison is only dependent on |
40 * [n] and not on the relationship of the match between [s1] and [s2]. | 40 * [n] and not on the relationship of the match between [s1] and [s2]. |
41 */ | 41 */ |
42 int SafeMemcmp(const void* s1, const void* s2, size_t n); | 42 int SafeMemcmp(const void* s1, const void* s2, size_t n); |
43 | 43 |
44 /* Track remaining data to be read in a buffer. */ | 44 /* Track remaining data to be read in a buffer. */ |
45 typedef struct MemcpyState { | 45 typedef struct MemcpyState { |
46 void* remaining_buf; | 46 void* remaining_buf; |
47 uint64_t remaining_len; | 47 uint64_t remaining_len; /* Remaining length of the buffer. */ |
| 48 uint8_t overrun; /* Flag set to 1 when an overrun occurs. */ |
48 } MemcpyState; | 49 } MemcpyState; |
49 | 50 |
50 /* Copy [len] bytes into [dst] only if there's enough data to read according | 51 /* Copy [len] bytes into [dst] only if there's enough data to read according |
51 * to [state]. | 52 * to [state]. |
52 * On success, return [dst] and update [state]. | 53 * On success, return [dst] and update [state]. |
53 * On failure, return NULL, set remaining len in state to -1. | 54 * On failure, return NULL, set remaining len in state to -1. |
54 * | 55 * |
55 * Useful for iterating through a binary blob to populate a struct. After the | 56 * Useful for iterating through a binary blob to populate a struct. After the |
56 * first failure (buffer overrun), successive calls will always fail. | 57 * first failure (buffer overrun), successive calls will always fail. |
57 */ | 58 */ |
58 void* StatefulMemcpy(MemcpyState* state, void* dst, int len); | 59 void* StatefulMemcpy(MemcpyState* state, void* dst, uint64_t len); |
59 | 60 |
60 /* Like StatefulMemcpy() but copies in the opposite direction, populating | 61 /* Like StatefulMemcpy() but copies in the opposite direction, populating |
61 * data from [src] into the buffer encapsulated in state [state]. | 62 * data from [src] into the buffer encapsulated in state [state]. |
62 * On success, return [src] and update [state]. | 63 * On success, return [src] and update [state]. |
63 * On failure, return NULL, set remaining_len in state to -1. | 64 * On failure, return NULL, set remaining_len in state to -1. |
64 * | 65 * |
65 * Useful for iterating through a structure to populate a binary blob. After the | 66 * Useful for iterating through a structure to populate a binary blob. After the |
66 * first failure (buffer overrun), successive calls will always fail. | 67 * first failure (buffer overrun), successive calls will always fail. |
67 */ | 68 */ |
68 const void* StatefulMemcpy_r(MemcpyState* state, const void* src, int len); | 69 const void* StatefulMemcpy_r(MemcpyState* state, const void* src, uint64_t len); |
69 | 70 |
70 #endif /* VBOOT_REFERENCE_UTILITY_H_ */ | 71 #endif /* VBOOT_REFERENCE_UTILITY_H_ */ |
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