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 <linux/kernel.h>
   9 #include <linux/types.h>
  10
  11 static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
  12 static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
  13 static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }
  14
  15 typedef  uint8_t BYTE;
  16 typedef uint16_t U16;
  17 typedef uint32_t U32;
  18 typedef  int32_t S32;
  19 typedef uint64_t U64;
  20
  21 #define FORCE_INLINE static inline __attribute__((always_inline))
  22
  23 /* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
  24 #include "lz4.c"        /* #include for inlining, do not link! */
  25
  26 #define LZ4F_MAGIC 0x184D2204
  27
  28 struct lz4_frame_header {
  29         u32 magic;
  30         union {
  31                 u8 flags;
  32                 struct {
  33                         u8 reserved0:2;
  34                         u8 has_content_checksum:1;
  35                         u8 has_content_size:1;
  36                         u8 has_block_checksum:1;
  37                         u8 independent_blocks:1;
  38                         u8 version:2;
  39                 };
  40         };
  41         union {
  42                 u8 block_descriptor;
  43                 struct {
  44                         u8 reserved1:4;
  45                         u8 max_block_size:3;
  46                         u8 reserved2:1;
  47                 };
  48         };
  49         /* + u64 content_size iff has_content_size is set */
  50         /* + u8 header_checksum */
  51 } __packed;
  52
  53 struct lz4_block_header {
  54         union {
  55                 u32 raw;
  56                 struct {
  57                         u32 size:31;
  58                         u32 not_compressed:1;
  59                 };
  60         };
  61         /* + size bytes of data */
  62         /* + u32 block_checksum iff has_block_checksum is set */
  63 } __packed;
  64
  65 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
  66 {
  67         const void *end = dst + *dstn;
  68         const void *in = src;
  69         void *out = dst;
  70         int has_block_checksum;
  71         int ret;
  72         *dstn = 0;
  73
  74         { /* With in-place decompression the header may become invalid later. */
  75                 const struct lz4_frame_header *h = in;
  76
  77                 if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
  78                         return -EINVAL; /* input overrun */
  79
  80                 /* We assume there's always only a single, standard frame. */
  81                 if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
  82                         return -EPROTONOSUPPORT;        /* unknown format */
  83                 if (h->reserved0 || h->reserved1 || h->reserved2)
  84                         return -EINVAL; /* reserved must be zero */
  85                 if (!h->independent_blocks)
  86                         return -EPROTONOSUPPORT; /* we can't support this yet */
  87                 has_block_checksum = h->has_block_checksum;
  88
  89                 in += sizeof(*h);
  90                 if (h->has_content_size)
  91                         in += sizeof(u64);
  92                 in += sizeof(u8);
  93         }
  94
  95         while (1) {
  96                 struct lz4_block_header b;
  97
  98                 b.raw = le32_to_cpu(*(u32 *)in);
  99                 in += sizeof(struct lz4_block_header);
 100
 101                 if (in - src + b.size > srcn) {
 102                         ret = -EINVAL;          /* input overrun */
 103                         break;
 104                 }
 105
 106                 if (!b.size) {
 107                         ret = 0;        /* decompression successful */
 108                         break;
 109                 }
 110
 111                 if (b.not_compressed) {
 112                         size_t size = min((ptrdiff_t)b.size, end - out);
 113                         memcpy(out, in, size);
 114                         out += size;
 115                         if (size < b.size) {
 116                                 ret = -ENOBUFS; /* output overrun */
 117                                 break;
 118                         }
 119                 } else {
 120                         /* constant folding essential, do not touch params! */
 121                         ret = LZ4_decompress_generic(in, out, b.size,
 122                                         end - out, endOnInputSize,
 123                                         full, 0, noDict, out, NULL, 0);
 124                         if (ret < 0) {
 125                                 ret = -EPROTO;  /* decompression error */
 126                                 break;
 127                         }
 128                         out += ret;
 129                 }
 130
 131                 in += b.size;
 132                 if (has_block_checksum)
 133                         in += sizeof(u32);
 134         }
 135
 136         *dstn = out - dst;
 137         return ret;
 138 }