lib/lz4_wrapper.c

   1 /*
   2  * Copyright 2015 Google Inc.
   3  *
   4  * SPDX-License-Identifier: GPL 2.0+ BSD-3-Clause
   5  */
   6
   7 #include <common.h>
   8 #include <compiler.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 #define LZ4F_MAGIC 0x184D2204
  28
  29 struct lz4_frame_header {
  30         u32 magic;
  31         union {
  32                 u8 flags;
  33                 struct {
  34                         u8 reserved0:2;
  35                         u8 has_content_checksum:1;
  36                         u8 has_content_size:1;
  37                         u8 has_block_checksum:1;
  38                         u8 independent_blocks:1;
  39                         u8 version:2;
  40                 };
  41         };
  42         union {
  43                 u8 block_descriptor;
  44                 struct {
  45                         u8 reserved1:4;
  46                         u8 max_block_size:3;
  47                         u8 reserved2:1;
  48                 };
  49         };
  50         /* + u64 content_size iff has_content_size is set */
  51         /* + u8 header_checksum */
  52 } __packed;
  53
  54 struct lz4_block_header {
  55         union {
  56                 u32 raw;
  57                 struct {
  58                         u32 size:31;
  59                         u32 not_compressed:1;
  60                 };
  61         };
  62         /* + size bytes of data */
  63         /* + u32 block_checksum iff has_block_checksum is set */
  64 } __packed;
  65
  66 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
  67 {
  68         const void *end = dst + *dstn;
  69         const void *in = src;
  70         void *out = dst;
  71         int has_block_checksum;
  72         int ret;
  73         *dstn = 0;
  74
  75         { /* With in-place decompression the header may become invalid later. */
  76                 const struct lz4_frame_header *h = in;
  77
  78                 if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
  79                         return -EINVAL; /* input overrun */
  80
  81                 /* We assume there's always only a single, standard frame. */
  82                 if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
  83                         return -EPROTONOSUPPORT;        /* unknown format */
  84                 if (h->reserved0 || h->reserved1 || h->reserved2)
  85                         return -EINVAL; /* reserved must be zero */
  86                 if (!h->independent_blocks)
  87                         return -EPROTONOSUPPORT; /* we can't support this yet */
  88                 has_block_checksum = h->has_block_checksum;
  89
  90                 in += sizeof(*h);
  91                 if (h->has_content_size)
  92                         in += sizeof(u64);
  93                 in += sizeof(u8);
  94         }
  95
  96         while (1) {
  97                 struct lz4_block_header 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 }