diff options
Diffstat (limited to 'src/journal/compress.c')
| -rw-r--r-- | src/journal/compress.c | 43 |
1 files changed, 26 insertions, 17 deletions
diff --git a/src/journal/compress.c b/src/journal/compress.c index 6baf15c8ff..e95ce2bcaa 100644 --- a/src/journal/compress.c +++ b/src/journal/compress.c @@ -95,11 +95,7 @@ int compress_blob_lz4(const void *src, uint64_t src_size, if (src_size < 9) return -ENOBUFS; -#if LZ4_VERSION_NUMBER >= 10700 r = LZ4_compress_default(src, (char*)dst + 8, src_size, (int) dst_alloc_size - 8); -#else - r = LZ4_compress_limitedOutput(src, (char*)dst + 8, src_size, (int) dst_alloc_size - 8); -#endif if (r <= 0) return -ENOBUFS; @@ -294,7 +290,6 @@ int decompress_startswith_lz4(const void *src, uint64_t src_size, * prefix */ int r; - size_t size; assert(src); assert(src_size > 0); @@ -311,23 +306,37 @@ int decompress_startswith_lz4(const void *src, uint64_t src_size, r = LZ4_decompress_safe_partial((char*)src + 8, *buffer, src_size - 8, prefix_len + 1, *buffer_size); - if (r >= 0) - size = (unsigned) r; - else { - /* lz4 always tries to decode full "sequence", so in - * pathological cases might need to decompress the - * full field. */ + /* One lz4 < 1.8.3, we might get "failure" (r < 0), or "success" where + * just a part of the buffer is decompressed. But if we get a smaller + * amount of bytes than requested, we don't know whether there isn't enough + * data to fill the requested size or whether we just got a partial answer. + */ + if (r < 0 || (size_t) r < prefix_len + 1) { + size_t size; + + if (LZ4_versionNumber() >= 10803) + /* We trust that the newer lz4 decompresses the number of bytes we + * requested if available in the compressed string. */ + return 0; + + if (r > 0) + /* Compare what we have first, in case of mismatch we can + * shortcut the full comparison. */ + if (memcmp(*buffer, prefix, r) != 0) + return 0; + + /* Before version 1.8.3, lz4 always tries to decode full a "sequence", + * so in pathological cases might need to decompress the full field. */ r = decompress_blob_lz4(src, src_size, buffer, buffer_size, &size, 0); if (r < 0) return r; - } - if (size >= prefix_len + 1) - return memcmp(*buffer, prefix, prefix_len) == 0 && - ((const uint8_t*) *buffer)[prefix_len] == extra; - else - return 0; + if (size < prefix_len + 1) + return 0; + } + return memcmp(*buffer, prefix, prefix_len) == 0 && + ((const uint8_t*) *buffer)[prefix_len] == extra; #else return -EPROTONOSUPPORT; #endif |