| 1 | |
| 2 | |
| 3 | * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
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| 4 | *
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| 5 | * Copyright (C) 2013, LG Electronics, Kyungsik Lee <[email protected]>
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| 6 |
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| 7 |
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| 8 | #ifdef STATIC
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| 9 | #define PREBOOT
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| 10 | #include "lz4/lz4_decompress.c"
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| 11 | #else
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| 12 | #include <linux/decompress/unlz4.h>
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| 13 | #endif
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| 14 | #include <linux/types.h>
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| 15 | #include <linux/lz4.h>
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| 16 | #include <linux/decompress/mm.h>
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| 17 | #include <linux/compiler.h>
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| 18 |
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| 19 | #include <linux/unaligned.h>
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| 20 |
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| 21 | |
| 22 | * Note: Uncompressed chunk size is used in the compressor side
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| 23 | * (userspace side for compression).
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| 24 | * It is hardcoded because there is not proper way to extract it
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| 25 | * from the binary stream which is generated by the preliminary
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| 26 | * version of LZ4 tool so far.
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| 27 |
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| 28 | #define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
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| 29 | #define ARCHIVE_MAGICNUMBER 0x184C2102
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| 30 |
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| 31 | STATIC inline int INIT unlz4(u8 *input, long in_len,
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| 32 | long (*fill)(void *, unsigned long),
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| 33 | long (*flush)(void *, unsigned long),
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| 34 | u8 *output, long *posp,
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| 35 | void (*error) (char *x))
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| 36 | {
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| 37 | int ret = -1;
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| 38 | size_t chunksize = 0;
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| 39 | size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
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| 40 | u8 *inp;
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| 41 | u8 *inp_start;
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| 42 | u8 *outp;
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| 43 | long size = in_len;
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| 44 | #ifdef PREBOOT
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| 45 | size_t out_len = get_unaligned_le32(input + in_len);
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| 46 | #endif
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| 47 | size_t dest_len;
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| 48 |
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| 49 |
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| 50 | if (output) {
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| 51 | outp = output;
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| 52 | } else if (!flush) {
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| 53 | error("NULL output pointer and no flush function provided");
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| 54 | goto exit_0;
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| 55 | } else {
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| 56 | outp = large_malloc(uncomp_chunksize);
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| 57 | if (!outp) {
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| 58 | error("Could not allocate output buffer");
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| 59 | goto exit_0;
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| 60 | }
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| 61 | }
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| 62 |
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| 63 | if (input && fill) {
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| 64 | error("Both input pointer and fill function provided,");
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| 65 | goto exit_1;
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| 66 | } else if (input) {
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| 67 | inp = input;
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| 68 | } else if (!fill) {
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| 69 | error("NULL input pointer and missing fill function");
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| 70 | goto exit_1;
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| 71 | } else {
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| 72 | inp = large_malloc(LZ4_compressBound(uncomp_chunksize));
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| 73 | if (!inp) {
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| 74 | error("Could not allocate input buffer");
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| 75 | goto exit_1;
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| 76 | }
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| 77 | }
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| 78 | inp_start = inp;
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| 79 |
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| 80 | if (posp)
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| 81 | *posp = 0;
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| 82 |
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| 83 | if (fill) {
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| 84 | size = fill(inp, 4);
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| 85 | if (size < 4) {
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| 86 | error("data corrupted");
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| 87 | goto exit_2;
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| 88 | }
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| 89 | }
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| 90 |
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| 91 | chunksize = get_unaligned_le32(inp);
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| 92 | if (chunksize == ARCHIVE_MAGICNUMBER) {
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| 93 | if (!fill) {
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| 94 | inp += 4;
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| 95 | size -= 4;
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| 96 | }
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| 97 | } else {
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| 98 | error("invalid header");
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| 99 | goto exit_2;
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| 100 | }
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| 101 |
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| 102 | if (posp)
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| 103 | *posp += 4;
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| 104 |
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| 105 | for (;;) {
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| 106 |
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| 107 | if (fill) {
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| 108 | size = fill(inp, 4);
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| 109 | if (size == 0)
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| 110 | break;
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| 111 | if (size < 4) {
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| 112 | error("data corrupted");
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| 113 | goto exit_2;
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| 114 | }
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| 115 | } else if (size < 4) {
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| 116 |
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| 117 | goto exit_3;
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| 118 | }
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| 119 |
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| 120 | chunksize = get_unaligned_le32(inp);
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| 121 | if (chunksize == ARCHIVE_MAGICNUMBER) {
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| 122 | if (!fill) {
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| 123 | inp += 4;
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| 124 | size -= 4;
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| 125 | }
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| 126 | if (posp)
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| 127 | *posp += 4;
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| 128 | continue;
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| 129 | }
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| 130 |
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| 131 | if (!fill && chunksize == 0) {
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| 132 |
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| 133 | goto exit_3;
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| 134 | }
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| 135 |
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| 136 | if (posp)
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| 137 | *posp += 4;
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| 138 |
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| 139 | if (!fill) {
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| 140 | inp += 4;
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| 141 | size -= 4;
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| 142 | } else {
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| 143 | if (chunksize > LZ4_compressBound(uncomp_chunksize)) {
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| 144 | error("chunk length is longer than allocated");
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| 145 | goto exit_2;
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| 146 | }
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| 147 | size = fill(inp, chunksize);
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| 148 | if (size < chunksize) {
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| 149 | error("data corrupted");
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| 150 | goto exit_2;
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| 151 | }
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| 152 | }
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| 153 | #ifdef PREBOOT
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| 154 | if (out_len >= uncomp_chunksize) {
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| 155 | dest_len = uncomp_chunksize;
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| 156 | out_len -= dest_len;
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| 157 | } else
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| 158 | dest_len = out_len;
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| 159 |
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| 160 | ret = LZ4_decompress_fast(inp, outp, dest_len);
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| 161 | chunksize = ret;
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| 162 | #else
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| 163 | dest_len = uncomp_chunksize;
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| 164 |
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| 165 | ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len);
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| 166 | dest_len = ret;
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| 167 | #endif
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| 168 | if (ret < 0) {
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| 169 | error("Decoding failed");
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| 170 | goto exit_2;
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| 171 | }
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| 172 |
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| 173 | ret = -1;
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| 174 | if (flush && flush(outp, dest_len) != dest_len)
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| 175 | goto exit_2;
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| 176 | if (output)
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| 177 | outp += dest_len;
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| 178 | if (posp)
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| 179 | *posp += chunksize;
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| 180 |
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| 181 | if (!fill) {
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| 182 | size -= chunksize;
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| 183 |
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| 184 | if (size == 0)
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| 185 | break;
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| 186 | else if (size < 0) {
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| 187 | error("data corrupted");
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| 188 | goto exit_2;
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| 189 | }
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| 190 | inp += chunksize;
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| 191 | }
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| 192 | }
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| 193 |
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| 194 | exit_3:
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| 195 | ret = 0;
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| 196 | exit_2:
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| 197 | if (!input)
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| 198 | large_free(inp_start);
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| 199 | exit_1:
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| 200 | if (!output)
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| 201 | large_free(outp);
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| 202 | exit_0:
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| 203 | return ret;
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| 204 | }
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| 205 |
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| 206 | #ifdef PREBOOT
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| 207 | STATIC int INIT __decompress(unsigned char *buf, long in_len,
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| 208 | long (*fill)(void*, unsigned long),
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| 209 | long (*flush)(void*, unsigned long),
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| 210 | unsigned char *output, long out_len,
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| 211 | long *posp,
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| 212 | void (*error)(char *x)
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| 213 | )
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| 214 | {
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| 215 | return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
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| 216 | }
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| 217 | #endif
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