fs/erofs/decompress.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 #include "decompress.h"
   3
   4 #if IS_ENABLED(CONFIG_LZ4)
   5 #include <u-boot/lz4.h>
   6 static int z_erofs_decompress_lz4(struct z_erofs_decompress_req *rq)
   7 {
   8         int ret = 0;
   9         char *dest = rq->out;
  10         char *src = rq->in;
  11         char *buff = NULL;
  12         bool support_0padding = false;
  13         unsigned int inputmargin = 0;
  14
  15         if (erofs_sb_has_lz4_0padding()) {
  16                 support_0padding = true;
  17
  18                 while (!src[inputmargin & ~PAGE_MASK])
  19                         if (!(++inputmargin & ~PAGE_MASK))
  20                                 break;
  21
  22                 if (inputmargin >= rq->inputsize)
  23                         return -EIO;
  24         }
  25
  26         if (rq->decodedskip) {
  27                 buff = malloc(rq->decodedlength);
  28                 if (!buff)
  29                         return -ENOMEM;
  30                 dest = buff;
  31         }
  32
  33         if (rq->partial_decoding || !support_0padding)
  34                 ret = LZ4_decompress_safe_partial(src + inputmargin, dest,
  35                                                   rq->inputsize - inputmargin,
  36                                                   rq->decodedlength, rq->decodedlength);
  37         else
  38                 ret = LZ4_decompress_safe(src + inputmargin, dest,
  39                                           rq->inputsize - inputmargin,
  40                                           rq->decodedlength);
  41
  42         if (ret != (int)rq->decodedlength) {
  43                 ret = -EIO;
  44                 goto out;
  45         }
  46
  47         if (rq->decodedskip)
  48                 memcpy(rq->out, dest + rq->decodedskip,
  49                        rq->decodedlength - rq->decodedskip);
  50
  51 out:
  52         if (buff)
  53                 free(buff);
  54
  55         return ret;
  56 }
  57 #endif
  58
  59 int z_erofs_decompress(struct z_erofs_decompress_req *rq)
  60 {
  61         if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
  62                 if (rq->inputsize != EROFS_BLKSIZ)
  63                         return -EFSCORRUPTED;
  64
  65                 DBG_BUGON(rq->decodedlength > EROFS_BLKSIZ);
  66                 DBG_BUGON(rq->decodedlength < rq->decodedskip);
  67
  68                 memcpy(rq->out, rq->in + rq->decodedskip,
  69                        rq->decodedlength - rq->decodedskip);
  70                 return 0;
  71         }
  72
  73 #if IS_ENABLED(CONFIG_LZ4)
  74         if (rq->alg == Z_EROFS_COMPRESSION_LZ4)
  75                 return z_erofs_decompress_lz4(rq);
  76 #endif
  77         return -EOPNOTSUPP;
  78 }