the-tree/lib/decompress_unlz4.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
0004  *
0005  * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
0006  */
0007
0008 #ifdef STATIC
0009 #define PREBOOT
0010 #include "lz4/lz4_decompress.c"
0011 #else
0012 #include <linux/decompress/unlz4.h>
0013 #endif
0014 #include <linux/types.h>
0015 #include <linux/lz4.h>
0016 #include <linux/decompress/mm.h>
0017 #include <linux/compiler.h>
0018
0019 #include <asm/unaligned.h>
0020
0021 /*
0022  * Note: Uncompressed chunk size is used in the compressor side
0023  * (userspace side for compression).
0024  * It is hardcoded because there is not proper way to extract it
0025  * from the binary stream which is generated by the preliminary
0026  * version of LZ4 tool so far.
0027  */
0028 #define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
0029 #define ARCHIVE_MAGICNUMBER 0x184C2102
0030
0031 STATIC inline int INIT unlz4(u8 *input, long in_len,
0032                 long (*fill)(void *, unsigned long),
0033                 long (*flush)(void *, unsigned long),
0034                 u8 *output, long *posp,
0035                 void (*error) (char *x))
0036 {
0037     int ret = -1;
0038     size_t chunksize = 0;
0039     size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
0040     u8 *inp;
0041     u8 *inp_start;
0042     u8 *outp;
0043     long size = in_len;
0044 #ifdef PREBOOT
0045     size_t out_len = get_unaligned_le32(input + in_len);
0046 #endif
0047     size_t dest_len;
0048
0049
0050     if (output) {
0051         outp = output;
0052     } else if (!flush) {
0053         error("NULL output pointer and no flush function provided");
0054         goto exit_0;
0055     } else {
0056         outp = large_malloc(uncomp_chunksize);
0057         if (!outp) {
0058             error("Could not allocate output buffer");
0059             goto exit_0;
0060         }
0061     }
0062
0063     if (input && fill) {
0064         error("Both input pointer and fill function provided,");
0065         goto exit_1;
0066     } else if (input) {
0067         inp = input;
0068     } else if (!fill) {
0069         error("NULL input pointer and missing fill function");
0070         goto exit_1;
0071     } else {
0072         inp = large_malloc(LZ4_compressBound(uncomp_chunksize));
0073         if (!inp) {
0074             error("Could not allocate input buffer");
0075             goto exit_1;
0076         }
0077     }
0078     inp_start = inp;
0079
0080     if (posp)
0081         *posp = 0;
0082
0083     if (fill) {
0084         size = fill(inp, 4);
0085         if (size < 4) {
0086             error("data corrupted");
0087             goto exit_2;
0088         }
0089     }
0090
0091     chunksize = get_unaligned_le32(inp);
0092     if (chunksize == ARCHIVE_MAGICNUMBER) {
0093         if (!fill) {
0094             inp += 4;
0095             size -= 4;
0096         }
0097     } else {
0098         error("invalid header");
0099         goto exit_2;
0100     }
0101
0102     if (posp)
0103         *posp += 4;
0104
0105     for (;;) {
0106
0107         if (fill) {
0108             size = fill(inp, 4);
0109             if (size == 0)
0110                 break;
0111             if (size < 4) {
0112                 error("data corrupted");
0113                 goto exit_2;
0114             }
0115         } else if (size < 4) {
0116             /* empty or end-of-file */
0117             goto exit_3;
0118         }
0119
0120         chunksize = get_unaligned_le32(inp);
0121         if (chunksize == ARCHIVE_MAGICNUMBER) {
0122             if (!fill) {
0123                 inp += 4;
0124                 size -= 4;
0125             }
0126             if (posp)
0127                 *posp += 4;
0128             continue;
0129         }
0130
0131         if (!fill && chunksize == 0) {
0132             /* empty or end-of-file */
0133             goto exit_3;
0134         }
0135
0136         if (posp)
0137             *posp += 4;
0138
0139         if (!fill) {
0140             inp += 4;
0141             size -= 4;
0142         } else {
0143             if (chunksize > LZ4_compressBound(uncomp_chunksize)) {
0144                 error("chunk length is longer than allocated");
0145                 goto exit_2;
0146             }
0147             size = fill(inp, chunksize);
0148             if (size < chunksize) {
0149                 error("data corrupted");
0150                 goto exit_2;
0151             }
0152         }
0153 #ifdef PREBOOT
0154         if (out_len >= uncomp_chunksize) {
0155             dest_len = uncomp_chunksize;
0156             out_len -= dest_len;
0157         } else
0158             dest_len = out_len;
0159
0160         ret = LZ4_decompress_fast(inp, outp, dest_len);
0161         chunksize = ret;
0162 #else
0163         dest_len = uncomp_chunksize;
0164
0165         ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len);
0166         dest_len = ret;
0167 #endif
0168         if (ret < 0) {
0169             error("Decoding failed");
0170             goto exit_2;
0171         }
0172
0173         ret = -1;
0174         if (flush && flush(outp, dest_len) != dest_len)
0175             goto exit_2;
0176         if (output)
0177             outp += dest_len;
0178         if (posp)
0179             *posp += chunksize;
0180
0181         if (!fill) {
0182             size -= chunksize;
0183
0184             if (size == 0)
0185                 break;
0186             else if (size < 0) {
0187                 error("data corrupted");
0188                 goto exit_2;
0189             }
0190             inp += chunksize;
0191         }
0192     }
0193
0194 exit_3:
0195     ret = 0;
0196 exit_2:
0197     if (!input)
0198         large_free(inp_start);
0199 exit_1:
0200     if (!output)
0201         large_free(outp);
0202 exit_0:
0203     return ret;
0204 }
0205
0206 #ifdef PREBOOT
0207 STATIC int INIT __decompress(unsigned char *buf, long in_len,
0208                   long (*fill)(void*, unsigned long),
0209                   long (*flush)(void*, unsigned long),
0210                   unsigned char *output, long out_len,
0211                   long *posp,
0212                   void (*error)(char *x)
0213     )
0214 {
0215     return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
0216 }
0217 #endif