lib/lz4_wrapper.c

   1 // SPDX-License-Identifier: GPL 2.0+ OR BSD-3-Clause
   2 /*
   3  * Copyright 2015 Google Inc.
   4  */
   5
   6 #include <common.h>
   7 #include <compiler.h>
   8 #include <image.h>
   9 #include <linux/kernel.h>
  10 #include <linux/types.h>
  11
  12 static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
  13 static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
  14 static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }
  15
  16 typedef  uint8_t BYTE;
  17 typedef uint16_t U16;
  18 typedef uint32_t U32;
  19 typedef  int32_t S32;
  20 typedef uint64_t U64;
  21
  22 #define FORCE_INLINE static inline __attribute__((always_inline))
  23
  24 /* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
  25 #include "lz4.c"        /* #include for inlining, do not link! */
  26
  27 struct lz4_frame_header {
  28         u32 magic;
  29         union {
  30                 u8 flags;
  31                 struct {
  32                         u8 reserved0:2;
  33                         u8 has_content_checksum:1;
  34                         u8 has_content_size:1;
  35                         u8 has_block_checksum:1;
  36                         u8 independent_blocks:1;
  37                         u8 version:2;
  38                 };
  39         };
  40         union {
  41                 u8 block_descriptor;
  42                 struct {
  43                         u8 reserved1:4;
  44                         u8 max_block_size:3;
  45                         u8 reserved2:1;
  46                 };
  47         };
  48         /* + u64 content_size iff has_content_size is set */
  49         /* + u8 header_checksum */
  50 } __packed;
  51
  52 struct lz4_block_header {
  53         union {
  54                 u32 raw;
  55                 struct {
  56                         u32 size:31;
  57                         u32 not_compressed:1;
  58                 };
  59         };
  60         /* + size bytes of data */
  61         /* + u32 block_checksum iff has_block_checksum is set */
  62 } __packed;
  63
  64 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
  65 {
  66         const void *end = dst + *dstn;
  67         const void *in = src;
  68         void *out = dst;
  69         int has_block_checksum;
  70         int ret;
  71         *dstn = 0;
  72
  73         { /* With in-place decompression the header may become invalid later. */
  74                 const struct lz4_frame_header *h = in;
  75
  76                 if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
  77                         return -EINVAL; /* input overrun */
  78
  79                 /* We assume there's always only a single, standard frame. */
  80                 if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
  81                         return -EPROTONOSUPPORT;        /* unknown format */
  82                 if (h->reserved0 || h->reserved1 || h->reserved2)
  83                         return -EINVAL; /* reserved must be zero */
  84                 if (!h->independent_blocks)
  85                         return -EPROTONOSUPPORT; /* we can't support this yet */
  86                 has_block_checksum = h->has_block_checksum;
  87
  88                 in += sizeof(*h);
  89                 if (h->has_content_size)
  90                         in += sizeof(u64);
  91                 in += sizeof(u8);
  92         }
  93
  94         while (1) {
  95                 struct lz4_block_header b;
  96
  97                 b.raw = le32_to_cpu(*(u32 *)in);
  98                 in += sizeof(struct lz4_block_header);
  99
 100                 if (in - src + b.size > srcn) {
 101                         ret = -EINVAL;          /* input overrun */
 102                         break;
 103                 }
 104
 105                 if (!b.size) {
 106                         ret = 0;        /* decompression successful */
 107                         break;
 108                 }
 109
 110                 if (b.not_compressed) {
 111                         size_t size = min((ptrdiff_t)b.size, end - out);
 112                         memcpy(out, in, size);
 113                         out += size;
 114                         if (size < b.size) {
 115                                 ret = -ENOBUFS; /* output overrun */
 116                                 break;
 117                         }
 118                 } else {
 119                         /* constant folding essential, do not touch params! */
 120                         ret = LZ4_decompress_generic(in, out, b.size,
 121                                         end - out, endOnInputSize,
 122                                         full, 0, noDict, out, NULL, 0);
 123                         if (ret < 0) {
 124                                 ret = -EPROTO;  /* decompression error */
 125                                 break;
 126                         }
 127                         out += ret;
 128                 }
 129
 130                 in += b.size;
 131                 if (has_block_checksum)
 132                         in += sizeof(u32);
 133         }
 134
 135         *dstn = out - dst;
 136         return ret;
 137 }