| 1 | |
| 2 | |
| 3 | * vpd_decode.c
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| 4 | *
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| 5 | * Google VPD decoding routines.
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| 6 | *
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| 7 | * Copyright 2017 Google Inc.
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| 8 |
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| 9 |
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| 10 | #include "vpd_decode.h"
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| 11 |
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| 12 | static int vpd_decode_len(const u32 max_len, const u8 *in,
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| 13 | u32 *length, u32 *decoded_len)
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| 14 | {
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| 15 | u8 more;
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| 16 | int i = 0;
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| 17 |
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| 18 | if (!length || !decoded_len)
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| 19 | return VPD_FAIL;
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| 20 |
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| 21 | *length = 0;
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| 22 | do {
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| 23 | if (i >= max_len)
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| 24 | return VPD_FAIL;
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| 25 |
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| 26 | more = in[i] & 0x80;
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| 27 | *length <<= 7;
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| 28 | *length |= in[i] & 0x7f;
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| 29 | ++i;
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| 30 | } while (more);
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| 31 |
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| 32 | *decoded_len = i;
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| 33 | return VPD_OK;
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| 34 | }
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| 35 |
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| 36 | static int vpd_decode_entry(const u32 max_len, const u8 *input_buf,
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| 37 | u32 *_consumed, const u8 **entry, u32 *entry_len)
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| 38 | {
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| 39 | u32 decoded_len;
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| 40 | u32 consumed = *_consumed;
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| 41 |
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| 42 | if (vpd_decode_len(max_len - consumed, &input_buf[consumed],
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| 43 | entry_len, &decoded_len) != VPD_OK)
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| 44 | return VPD_FAIL;
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| 45 | if (max_len - consumed < decoded_len)
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| 46 | return VPD_FAIL;
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| 47 |
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| 48 | consumed += decoded_len;
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| 49 | *entry = input_buf + consumed;
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| 50 |
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| 51 |
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| 52 | if (max_len - consumed < *entry_len)
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| 53 | return VPD_FAIL;
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| 54 |
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| 55 | consumed += *entry_len;
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| 56 | *_consumed = consumed;
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| 57 | return VPD_OK;
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| 58 | }
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| 59 |
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| 60 | int vpd_decode_string(const u32 max_len, const u8 *input_buf, u32 *consumed,
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| 61 | vpd_decode_callback callback, void *callback_arg)
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| 62 | {
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| 63 | int type;
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| 64 | u32 key_len;
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| 65 | u32 value_len;
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| 66 | const u8 *key;
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| 67 | const u8 *value;
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| 68 |
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| 69 |
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| 70 | if (*consumed >= max_len)
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| 71 | return VPD_FAIL;
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| 72 |
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| 73 | type = input_buf[*consumed];
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| 74 |
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| 75 | switch (type) {
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| 76 | case VPD_TYPE_INFO:
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| 77 | case VPD_TYPE_STRING:
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| 78 | (*consumed)++;
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| 79 |
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| 80 | if (vpd_decode_entry(max_len, input_buf, consumed, &key,
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| 81 | &key_len) != VPD_OK)
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| 82 | return VPD_FAIL;
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| 83 |
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| 84 | if (vpd_decode_entry(max_len, input_buf, consumed, &value,
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| 85 | &value_len) != VPD_OK)
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| 86 | return VPD_FAIL;
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| 87 |
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| 88 | if (type == VPD_TYPE_STRING)
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| 89 | return callback(key, key_len, value, value_len,
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| 90 | callback_arg);
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| 91 | break;
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| 92 |
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| 93 | default:
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| 94 | return VPD_FAIL;
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| 95 | }
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| 96 |
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| 97 | return VPD_OK;
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| 98 | }
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