/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #include #include #if HAVE_XZ #include #endif #if HAVE_LZ4 #include #include #endif #if HAVE_ZSTD #include #include #endif #include "alloc-util.h" #include "compress.h" #include "fd-util.h" #include "fileio.h" #include "io-util.h" #include "macro.h" #include "sparse-endian.h" #include "string-table.h" #include "string-util.h" #include "unaligned.h" #if HAVE_LZ4 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(LZ4F_compressionContext_t, LZ4F_freeCompressionContext, NULL); DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(LZ4F_decompressionContext_t, LZ4F_freeDecompressionContext, NULL); #endif #if HAVE_ZSTD DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(ZSTD_CCtx*, ZSTD_freeCCtx, NULL); DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(ZSTD_DCtx*, ZSTD_freeDCtx, NULL); static int zstd_ret_to_errno(size_t ret) { switch (ZSTD_getErrorCode(ret)) { case ZSTD_error_dstSize_tooSmall: return -ENOBUFS; case ZSTD_error_memory_allocation: return -ENOMEM; default: return -EBADMSG; } } #endif #define ALIGN_8(l) ALIGN_TO(l, sizeof(size_t)) static const char* const compression_table[_COMPRESSION_MAX] = { [COMPRESSION_NONE] = "NONE", [COMPRESSION_XZ] = "XZ", [COMPRESSION_LZ4] = "LZ4", [COMPRESSION_ZSTD] = "ZSTD", }; DEFINE_STRING_TABLE_LOOKUP(compression, Compression); bool compression_supported(Compression c) { static const unsigned supported = (1U << COMPRESSION_NONE) | (1U << COMPRESSION_XZ) * HAVE_XZ | (1U << COMPRESSION_LZ4) * HAVE_LZ4 | (1U << COMPRESSION_ZSTD) * HAVE_ZSTD; return c >= 0 && c < _COMPRESSION_MAX && FLAGS_SET(supported, 1U << c); } int compress_blob_xz(const void *src, uint64_t src_size, void *dst, size_t dst_alloc_size, size_t *dst_size) { #if HAVE_XZ static const lzma_options_lzma opt = { 1u << 20u, NULL, 0, LZMA_LC_DEFAULT, LZMA_LP_DEFAULT, LZMA_PB_DEFAULT, LZMA_MODE_FAST, 128, LZMA_MF_HC3, 4 }; static const lzma_filter filters[] = { { LZMA_FILTER_LZMA2, (lzma_options_lzma*) &opt }, { LZMA_VLI_UNKNOWN, NULL } }; lzma_ret ret; size_t out_pos = 0; assert(src); assert(src_size > 0); assert(dst); assert(dst_alloc_size > 0); assert(dst_size); /* Returns < 0 if we couldn't compress the data or the * compressed result is longer than the original */ if (src_size < 80) return -ENOBUFS; ret = lzma_stream_buffer_encode((lzma_filter*) filters, LZMA_CHECK_NONE, NULL, src, src_size, dst, &out_pos, dst_alloc_size); if (ret != LZMA_OK) return -ENOBUFS; *dst_size = out_pos; return 0; #else return -EPROTONOSUPPORT; #endif } int compress_blob_lz4(const void *src, uint64_t src_size, void *dst, size_t dst_alloc_size, size_t *dst_size) { #if HAVE_LZ4 int r; assert(src); assert(src_size > 0); assert(dst); assert(dst_alloc_size > 0); assert(dst_size); /* Returns < 0 if we couldn't compress the data or the * compressed result is longer than the original */ if (src_size < 9) return -ENOBUFS; r = LZ4_compress_default(src, (char*)dst + 8, src_size, (int) dst_alloc_size - 8); if (r <= 0) return -ENOBUFS; unaligned_write_le64(dst, src_size); *dst_size = r + 8; return 0; #else return -EPROTONOSUPPORT; #endif } int compress_blob_zstd( const void *src, uint64_t src_size, void *dst, size_t dst_alloc_size, size_t *dst_size) { #if HAVE_ZSTD size_t k; assert(src); assert(src_size > 0); assert(dst); assert(dst_alloc_size > 0); assert(dst_size); k = ZSTD_compress(dst, dst_alloc_size, src, src_size, 0); if (ZSTD_isError(k)) return zstd_ret_to_errno(k); *dst_size = k; return 0; #else return -EPROTONOSUPPORT; #endif } int decompress_blob_xz( const void *src, uint64_t src_size, void **dst, size_t* dst_size, size_t dst_max) { #if HAVE_XZ _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT; lzma_ret ret; size_t space; assert(src); assert(src_size > 0); assert(dst); assert(dst_size); ret = lzma_stream_decoder(&s, UINT64_MAX, 0); if (ret != LZMA_OK) return -ENOMEM; space = MIN(src_size * 2, dst_max ?: SIZE_MAX); if (!greedy_realloc(dst, space, 1)) return -ENOMEM; s.next_in = src; s.avail_in = src_size; s.next_out = *dst; s.avail_out = space; for (;;) { size_t used; ret = lzma_code(&s, LZMA_FINISH); if (ret == LZMA_STREAM_END) break; else if (ret != LZMA_OK) return -ENOMEM; if (dst_max > 0 && (space - s.avail_out) >= dst_max) break; else if (dst_max > 0 && space == dst_max) return -ENOBUFS; used = space - s.avail_out; space = MIN(2 * space, dst_max ?: SIZE_MAX); if (!greedy_realloc(dst, space, 1)) return -ENOMEM; s.avail_out = space - used; s.next_out = *(uint8_t**)dst + used; } *dst_size = space - s.avail_out; return 0; #else return -EPROTONOSUPPORT; #endif } int decompress_blob_lz4( const void *src, uint64_t src_size, void **dst, size_t* dst_size, size_t dst_max) { #if HAVE_LZ4 char* out; int r, size; /* LZ4 uses int for size */ assert(src); assert(src_size > 0); assert(dst); assert(dst_size); if (src_size <= 8) return -EBADMSG; size = unaligned_read_le64(src); if (size < 0 || (unsigned) size != unaligned_read_le64(src)) return -EFBIG; out = greedy_realloc(dst, size, 1); if (!out) return -ENOMEM; r = LZ4_decompress_safe((char*)src + 8, out, src_size - 8, size); if (r < 0 || r != size) return -EBADMSG; *dst_size = size; return 0; #else return -EPROTONOSUPPORT; #endif } int decompress_blob_zstd( const void *src, uint64_t src_size, void **dst, size_t *dst_size, size_t dst_max) { #if HAVE_ZSTD uint64_t size; assert(src); assert(src_size > 0); assert(dst); assert(dst_size); size = ZSTD_getFrameContentSize(src, src_size); if (IN_SET(size, ZSTD_CONTENTSIZE_ERROR, ZSTD_CONTENTSIZE_UNKNOWN)) return -EBADMSG; if (dst_max > 0 && size > dst_max) size = dst_max; if (size > SIZE_MAX) return -E2BIG; if (!(greedy_realloc(dst, MAX(ZSTD_DStreamOutSize(), size), 1))) return -ENOMEM; _cleanup_(ZSTD_freeDCtxp) ZSTD_DCtx *dctx = ZSTD_createDCtx(); if (!dctx) return -ENOMEM; ZSTD_inBuffer input = { .src = src, .size = src_size, }; ZSTD_outBuffer output = { .dst = *dst, .size = MALLOC_SIZEOF_SAFE(*dst), }; size_t k = ZSTD_decompressStream(dctx, &output, &input); if (ZSTD_isError(k)) { log_debug("ZSTD decoder failed: %s", ZSTD_getErrorName(k)); return zstd_ret_to_errno(k); } assert(output.pos >= size); *dst_size = size; return 0; #else return -EPROTONOSUPPORT; #endif } int decompress_blob( Compression compression, const void *src, uint64_t src_size, void **dst, size_t* dst_size, size_t dst_max) { if (compression == COMPRESSION_XZ) return decompress_blob_xz( src, src_size, dst, dst_size, dst_max); else if (compression == COMPRESSION_LZ4) return decompress_blob_lz4( src, src_size, dst, dst_size, dst_max); else if (compression == COMPRESSION_ZSTD) return decompress_blob_zstd( src, src_size, dst, dst_size, dst_max); else return -EPROTONOSUPPORT; } int decompress_startswith_xz( const void *src, uint64_t src_size, void **buffer, const void *prefix, size_t prefix_len, uint8_t extra) { #if HAVE_XZ _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT; size_t allocated; lzma_ret ret; /* Checks whether the decompressed blob starts with the mentioned prefix. The byte extra needs to * follow the prefix */ assert(src); assert(src_size > 0); assert(buffer); assert(prefix); ret = lzma_stream_decoder(&s, UINT64_MAX, 0); if (ret != LZMA_OK) return -EBADMSG; if (!(greedy_realloc(buffer, ALIGN_8(prefix_len + 1), 1))) return -ENOMEM; allocated = MALLOC_SIZEOF_SAFE(*buffer); s.next_in = src; s.avail_in = src_size; s.next_out = *buffer; s.avail_out = allocated; for (;;) { ret = lzma_code(&s, LZMA_FINISH); if (!IN_SET(ret, LZMA_OK, LZMA_STREAM_END)) return -EBADMSG; if (allocated - s.avail_out >= prefix_len + 1) return memcmp(*buffer, prefix, prefix_len) == 0 && ((const uint8_t*) *buffer)[prefix_len] == extra; if (ret == LZMA_STREAM_END) return 0; s.avail_out += allocated; if (!(greedy_realloc(buffer, allocated * 2, 1))) return -ENOMEM; allocated = MALLOC_SIZEOF_SAFE(*buffer); s.next_out = *(uint8_t**)buffer + allocated - s.avail_out; } #else return -EPROTONOSUPPORT; #endif } int decompress_startswith_lz4( const void *src, uint64_t src_size, void **buffer, const void *prefix, size_t prefix_len, uint8_t extra) { #if HAVE_LZ4 /* Checks whether the decompressed blob starts with the mentioned prefix. The byte extra needs to * follow the prefix */ size_t allocated; int r; assert(src); assert(src_size > 0); assert(buffer); assert(prefix); if (src_size <= 8) return -EBADMSG; if (!(greedy_realloc(buffer, ALIGN_8(prefix_len + 1), 1))) return -ENOMEM; allocated = MALLOC_SIZEOF_SAFE(*buffer); r = LZ4_decompress_safe_partial( (char*)src + 8, *buffer, src_size - 8, prefix_len + 1, allocated); /* 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, &size, 0); if (r < 0) return r; 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 } int decompress_startswith_zstd( const void *src, uint64_t src_size, void **buffer, const void *prefix, size_t prefix_len, uint8_t extra) { #if HAVE_ZSTD assert(src); assert(src_size > 0); assert(buffer); assert(prefix); uint64_t size = ZSTD_getFrameContentSize(src, src_size); if (IN_SET(size, ZSTD_CONTENTSIZE_ERROR, ZSTD_CONTENTSIZE_UNKNOWN)) return -EBADMSG; if (size < prefix_len + 1) return 0; /* Decompressed text too short to match the prefix and extra */ _cleanup_(ZSTD_freeDCtxp) ZSTD_DCtx *dctx = ZSTD_createDCtx(); if (!dctx) return -ENOMEM; if (!(greedy_realloc(buffer, MAX(ZSTD_DStreamOutSize(), prefix_len + 1), 1))) return -ENOMEM; ZSTD_inBuffer input = { .src = src, .size = src_size, }; ZSTD_outBuffer output = { .dst = *buffer, .size = MALLOC_SIZEOF_SAFE(*buffer), }; size_t k; k = ZSTD_decompressStream(dctx, &output, &input); if (ZSTD_isError(k)) { log_debug("ZSTD decoder failed: %s", ZSTD_getErrorName(k)); return zstd_ret_to_errno(k); } assert(output.pos >= prefix_len + 1); return memcmp(*buffer, prefix, prefix_len) == 0 && ((const uint8_t*) *buffer)[prefix_len] == extra; #else return -EPROTONOSUPPORT; #endif } int decompress_startswith( Compression compression, const void *src, uint64_t src_size, void **buffer, const void *prefix, size_t prefix_len, uint8_t extra) { if (compression == COMPRESSION_XZ) return decompress_startswith_xz( src, src_size, buffer, prefix, prefix_len, extra); else if (compression == COMPRESSION_LZ4) return decompress_startswith_lz4( src, src_size, buffer, prefix, prefix_len, extra); else if (compression == COMPRESSION_ZSTD) return decompress_startswith_zstd( src, src_size, buffer, prefix, prefix_len, extra); else return -EBADMSG; } int compress_stream_xz(int fdf, int fdt, uint64_t max_bytes, uint64_t *ret_uncompressed_size) { #if HAVE_XZ _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT; lzma_ret ret; uint8_t buf[BUFSIZ], out[BUFSIZ]; lzma_action action = LZMA_RUN; assert(fdf >= 0); assert(fdt >= 0); ret = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_CRC64); if (ret != LZMA_OK) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize XZ encoder: code %u", ret); for (;;) { if (s.avail_in == 0 && action == LZMA_RUN) { size_t m = sizeof(buf); ssize_t n; if (max_bytes != UINT64_MAX && (uint64_t) m > max_bytes) m = (size_t) max_bytes; n = read(fdf, buf, m); if (n < 0) return -errno; if (n == 0) action = LZMA_FINISH; else { s.next_in = buf; s.avail_in = n; if (max_bytes != UINT64_MAX) { assert(max_bytes >= (uint64_t) n); max_bytes -= n; } } } if (s.avail_out == 0) { s.next_out = out; s.avail_out = sizeof(out); } ret = lzma_code(&s, action); if (!IN_SET(ret, LZMA_OK, LZMA_STREAM_END)) return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Compression failed: code %u", ret); if (s.avail_out == 0 || ret == LZMA_STREAM_END) { ssize_t n, k; n = sizeof(out) - s.avail_out; k = loop_write(fdt, out, n); if (k < 0) return k; if (ret == LZMA_STREAM_END) { if (ret_uncompressed_size) *ret_uncompressed_size = s.total_in; log_debug("XZ compression finished (%"PRIu64" -> %"PRIu64" bytes, %.1f%%)", s.total_in, s.total_out, (double) s.total_out / s.total_in * 100); return 0; } } } #else return -EPROTONOSUPPORT; #endif } #define LZ4_BUFSIZE (512*1024u) int compress_stream_lz4(int fdf, int fdt, uint64_t max_bytes, uint64_t *ret_uncompressed_size) { #if HAVE_LZ4 LZ4F_errorCode_t c; _cleanup_(LZ4F_freeCompressionContextp) LZ4F_compressionContext_t ctx = NULL; _cleanup_free_ void *in_buff = NULL; _cleanup_free_ char *out_buff = NULL; size_t out_allocsize, n, offset = 0, frame_size; uint64_t total_in = 0, total_out; int r; static const LZ4F_preferences_t preferences = { .frameInfo.blockSizeID = 5, }; c = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION); if (LZ4F_isError(c)) return -ENOMEM; frame_size = LZ4F_compressBound(LZ4_BUFSIZE, &preferences); out_allocsize = frame_size + 64*1024; /* add some space for header and trailer */ out_buff = malloc(out_allocsize); if (!out_buff) return -ENOMEM; in_buff = malloc(LZ4_BUFSIZE); if (!in_buff) return -ENOMEM; n = offset = total_out = LZ4F_compressBegin(ctx, out_buff, out_allocsize, &preferences); if (LZ4F_isError(n)) return -EINVAL; log_debug("Buffer size is %zu bytes, header size %zu bytes.", out_allocsize, n); for (;;) { ssize_t k; k = loop_read(fdf, in_buff, LZ4_BUFSIZE, true); if (k < 0) return k; if (k == 0) break; n = LZ4F_compressUpdate(ctx, out_buff + offset, out_allocsize - offset, in_buff, k, NULL); if (LZ4F_isError(n)) return -ENOTRECOVERABLE; total_in += k; offset += n; total_out += n; if (max_bytes != UINT64_MAX && total_out > (size_t) max_bytes) return log_debug_errno(SYNTHETIC_ERRNO(EFBIG), "Compressed stream longer than %" PRIu64 " bytes", max_bytes); if (out_allocsize - offset < frame_size + 4) { k = loop_write(fdt, out_buff, offset); if (k < 0) return k; offset = 0; } } n = LZ4F_compressEnd(ctx, out_buff + offset, out_allocsize - offset, NULL); if (LZ4F_isError(n)) return -ENOTRECOVERABLE; offset += n; total_out += n; r = loop_write(fdt, out_buff, offset); if (r < 0) return r; if (ret_uncompressed_size) *ret_uncompressed_size = total_in; if (total_in == 0) log_debug("LZ4 compression finished (no input data)"); else log_debug("LZ4 compression finished (%" PRIu64 " -> %" PRIu64 " bytes, %.1f%%)", total_in, total_out, (double) total_out / total_in * 100); return 0; #else return -EPROTONOSUPPORT; #endif } int decompress_stream_xz(int fdf, int fdt, uint64_t max_bytes) { #if HAVE_XZ _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT; lzma_ret ret; uint8_t buf[BUFSIZ], out[BUFSIZ]; lzma_action action = LZMA_RUN; assert(fdf >= 0); assert(fdt >= 0); ret = lzma_stream_decoder(&s, UINT64_MAX, 0); if (ret != LZMA_OK) return log_debug_errno(SYNTHETIC_ERRNO(ENOMEM), "Failed to initialize XZ decoder: code %u", ret); for (;;) { if (s.avail_in == 0 && action == LZMA_RUN) { ssize_t n; n = read(fdf, buf, sizeof(buf)); if (n < 0) return -errno; if (n == 0) action = LZMA_FINISH; else { s.next_in = buf; s.avail_in = n; } } if (s.avail_out == 0) { s.next_out = out; s.avail_out = sizeof(out); } ret = lzma_code(&s, action); if (!IN_SET(ret, LZMA_OK, LZMA_STREAM_END)) return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), "Decompression failed: code %u", ret); if (s.avail_out == 0 || ret == LZMA_STREAM_END) { ssize_t n, k; n = sizeof(out) - s.avail_out; if (max_bytes != UINT64_MAX) { if (max_bytes < (uint64_t) n) return -EFBIG; max_bytes -= n; } k = loop_write(fdt, out, n); if (k < 0) return k; if (ret == LZMA_STREAM_END) { log_debug("XZ decompression finished (%"PRIu64" -> %"PRIu64" bytes, %.1f%%)", s.total_in, s.total_out, (double) s.total_out / s.total_in * 100); return 0; } } } #else return log_debug_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "Cannot decompress file. Compiled without XZ support."); #endif } int decompress_stream_lz4(int in, int out, uint64_t max_bytes) { #if HAVE_LZ4 size_t c; _cleanup_(LZ4F_freeDecompressionContextp) LZ4F_decompressionContext_t ctx = NULL; _cleanup_free_ char *buf = NULL; char *src; struct stat st; int r = 0; size_t total_in = 0, total_out = 0; c = LZ4F_createDecompressionContext(&ctx, LZ4F_VERSION); if (LZ4F_isError(c)) return -ENOMEM; if (fstat(in, &st) < 0) return log_debug_errno(errno, "fstat() failed: %m"); if (file_offset_beyond_memory_size(st.st_size)) return -EFBIG; buf = malloc(LZ4_BUFSIZE); if (!buf) return -ENOMEM; src = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, in, 0); if (src == MAP_FAILED) return -errno; while (total_in < (size_t) st.st_size) { size_t produced = LZ4_BUFSIZE; size_t used = st.st_size - total_in; c = LZ4F_decompress(ctx, buf, &produced, src + total_in, &used, NULL); if (LZ4F_isError(c)) { r = -EBADMSG; goto cleanup; } total_in += used; total_out += produced; if (max_bytes != UINT64_MAX && total_out > (size_t) max_bytes) { log_debug("Decompressed stream longer than %"PRIu64" bytes", max_bytes); r = -EFBIG; goto cleanup; } r = loop_write(out, buf, produced); if (r < 0) goto cleanup; } log_debug("LZ4 decompression finished (%zu -> %zu bytes, %.1f%%)", total_in, total_out, total_in > 0 ? (double) total_out / total_in * 100 : 0.0); cleanup: munmap(src, st.st_size); return r; #else return log_debug_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "Cannot decompress file. Compiled without LZ4 support."); #endif } int compress_stream_zstd(int fdf, int fdt, uint64_t max_bytes, uint64_t *ret_uncompressed_size) { #if HAVE_ZSTD _cleanup_(ZSTD_freeCCtxp) ZSTD_CCtx *cctx = NULL; _cleanup_free_ void *in_buff = NULL, *out_buff = NULL; size_t in_allocsize, out_allocsize; size_t z; uint64_t left = max_bytes, in_bytes = 0; assert(fdf >= 0); assert(fdt >= 0); /* Create the context and buffers */ in_allocsize = ZSTD_CStreamInSize(); out_allocsize = ZSTD_CStreamOutSize(); in_buff = malloc(in_allocsize); out_buff = malloc(out_allocsize); cctx = ZSTD_createCCtx(); if (!cctx || !out_buff || !in_buff) return -ENOMEM; z = ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1); if (ZSTD_isError(z)) log_debug("Failed to enable ZSTD checksum, ignoring: %s", ZSTD_getErrorName(z)); /* This loop read from the input file, compresses that entire chunk, * and writes all output produced to the output file. */ for (;;) { bool is_last_chunk; ZSTD_inBuffer input = { .src = in_buff, .size = 0, .pos = 0 }; ssize_t red; red = loop_read(fdf, in_buff, in_allocsize, true); if (red < 0) return red; is_last_chunk = red == 0; in_bytes += (size_t) red; input.size = (size_t) red; for (bool finished = false; !finished;) { ZSTD_outBuffer output = { .dst = out_buff, .size = out_allocsize, .pos = 0 }; size_t remaining; ssize_t wrote; /* Compress into the output buffer and write all of the * output to the file so we can reuse the buffer next * iteration. */ remaining = ZSTD_compressStream2( cctx, &output, &input, is_last_chunk ? ZSTD_e_end : ZSTD_e_continue); if (ZSTD_isError(remaining)) { log_debug("ZSTD encoder failed: %s", ZSTD_getErrorName(remaining)); return zstd_ret_to_errno(remaining); } if (left < output.pos) return -EFBIG; wrote = loop_write_full(fdt, output.dst, output.pos, USEC_INFINITY); if (wrote < 0) return wrote; left -= output.pos; /* If we're on the last chunk we're finished when zstd * returns 0, which means its consumed all the input AND * finished the frame. Otherwise, we're finished when * we've consumed all the input. */ finished = is_last_chunk ? (remaining == 0) : (input.pos == input.size); } /* zstd only returns 0 when the input is completely consumed */ assert(input.pos == input.size); if (is_last_chunk) break; } if (ret_uncompressed_size) *ret_uncompressed_size = in_bytes; if (in_bytes > 0) log_debug("ZSTD compression finished (%" PRIu64 " -> %" PRIu64 " bytes, %.1f%%)", in_bytes, max_bytes - left, (double) (max_bytes - left) / in_bytes * 100); else log_debug("ZSTD compression finished (%" PRIu64 " -> %" PRIu64 " bytes)", in_bytes, max_bytes - left); return 0; #else return -EPROTONOSUPPORT; #endif } int decompress_stream_zstd(int fdf, int fdt, uint64_t max_bytes) { #if HAVE_ZSTD _cleanup_(ZSTD_freeDCtxp) ZSTD_DCtx *dctx = NULL; _cleanup_free_ void *in_buff = NULL, *out_buff = NULL; size_t in_allocsize, out_allocsize; size_t last_result = 0; uint64_t left = max_bytes, in_bytes = 0; assert(fdf >= 0); assert(fdt >= 0); /* Create the context and buffers */ in_allocsize = ZSTD_DStreamInSize(); out_allocsize = ZSTD_DStreamOutSize(); in_buff = malloc(in_allocsize); out_buff = malloc(out_allocsize); dctx = ZSTD_createDCtx(); if (!dctx || !out_buff || !in_buff) return -ENOMEM; /* This loop assumes that the input file is one or more concatenated * zstd streams. This example won't work if there is trailing non-zstd * data at the end, but streaming decompression in general handles this * case. ZSTD_decompressStream() returns 0 exactly when the frame is * completed, and doesn't consume input after the frame. */ for (;;) { bool has_error = false; ZSTD_inBuffer input = { .src = in_buff, .size = 0, .pos = 0 }; ssize_t red; red = loop_read(fdf, in_buff, in_allocsize, true); if (red < 0) return red; if (red == 0) break; in_bytes += (size_t) red; input.size = (size_t) red; input.pos = 0; /* Given a valid frame, zstd won't consume the last byte of the * frame until it has flushed all of the decompressed data of * the frame. So input.pos < input.size means frame is not done * or there is still output available. */ while (input.pos < input.size) { ZSTD_outBuffer output = { .dst = out_buff, .size = out_allocsize, .pos = 0 }; ssize_t wrote; /* The return code is zero if the frame is complete, but * there may be multiple frames concatenated together. * Zstd will automatically reset the context when a * frame is complete. Still, calling ZSTD_DCtx_reset() * can be useful to reset the context to a clean state, * for instance if the last decompression call returned * an error. */ last_result = ZSTD_decompressStream(dctx, &output, &input); if (ZSTD_isError(last_result)) { has_error = true; break; } if (left < output.pos) return -EFBIG; wrote = loop_write_full(fdt, output.dst, output.pos, USEC_INFINITY); if (wrote < 0) return wrote; left -= output.pos; } if (has_error) break; } if (in_bytes == 0) return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), "ZSTD decoder failed: no data read"); if (last_result != 0) { /* The last return value from ZSTD_decompressStream did not end * on a frame, but we reached the end of the file! We assume * this is an error, and the input was truncated. */ log_debug("ZSTD decoder failed: %s", ZSTD_getErrorName(last_result)); return zstd_ret_to_errno(last_result); } log_debug( "ZSTD decompression finished (%" PRIu64 " -> %" PRIu64 " bytes, %.1f%%)", in_bytes, max_bytes - left, (double) (max_bytes - left) / in_bytes * 100); return 0; #else return log_debug_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "Cannot decompress file. Compiled without ZSTD support."); #endif } int decompress_stream(const char *filename, int fdf, int fdt, uint64_t max_bytes) { if (endswith(filename, ".lz4")) return decompress_stream_lz4(fdf, fdt, max_bytes); else if (endswith(filename, ".xz")) return decompress_stream_xz(fdf, fdt, max_bytes); else if (endswith(filename, ".zst")) return decompress_stream_zstd(fdf, fdt, max_bytes); else return -EPROTONOSUPPORT; }