src/journal/compress.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/mman.h>
  25 #include <unistd.h>
  26
  27 #ifdef HAVE_XZ
  28 #include <lzma.h>
  29 #endif
  30
  31 #ifdef HAVE_LZ4
  32 #include <lz4.h>
  33 #include <lz4frame.h>
  34 #endif
  35
  36 #include "alloc-util.h"
  37 #include "compress.h"
  38 #include "fd-util.h"
  39 #include "io-util.h"
  40 #include "journal-def.h"
  41 #include "macro.h"
  42 #include "sparse-endian.h"
  43 #include "string-table.h"
  44 #include "string-util.h"
  45 #include "util.h"
  46
  47 #ifdef HAVE_LZ4
  48 DEFINE_TRIVIAL_CLEANUP_FUNC(LZ4F_compressionContext_t, LZ4F_freeCompressionContext);
  49 DEFINE_TRIVIAL_CLEANUP_FUNC(LZ4F_decompressionContext_t, LZ4F_freeDecompressionContext);
  50 #endif
  51
  52 #define ALIGN_8(l) ALIGN_TO(l, sizeof(size_t))
  53
  54 static const char* const object_compressed_table[_OBJECT_COMPRESSED_MAX] = {
  55         [OBJECT_COMPRESSED_XZ] = "XZ",
  56         [OBJECT_COMPRESSED_LZ4] = "LZ4",
  57 };
  58
  59 DEFINE_STRING_TABLE_LOOKUP(object_compressed, int);
  60
  61 int compress_blob_xz(const void *src, uint64_t src_size,
  62                      void *dst, size_t dst_alloc_size, size_t *dst_size) {
  63 #ifdef HAVE_XZ
  64         static const lzma_options_lzma opt = {
  65                 1u << 20u, NULL, 0, LZMA_LC_DEFAULT, LZMA_LP_DEFAULT,
  66                 LZMA_PB_DEFAULT, LZMA_MODE_FAST, 128, LZMA_MF_HC3, 4
  67         };
  68         static const lzma_filter filters[] = {
  69                 { LZMA_FILTER_LZMA2, (lzma_options_lzma*) &opt },
  70                 { LZMA_VLI_UNKNOWN, NULL }
  71         };
  72         lzma_ret ret;
  73         size_t out_pos = 0;
  74
  75         assert(src);
  76         assert(src_size > 0);
  77         assert(dst);
  78         assert(dst_alloc_size > 0);
  79         assert(dst_size);
  80
  81         /* Returns < 0 if we couldn't compress the data or the
  82          * compressed result is longer than the original */
  83
  84         if (src_size < 80)
  85                 return -ENOBUFS;
  86
  87         ret = lzma_stream_buffer_encode((lzma_filter*) filters, LZMA_CHECK_NONE, NULL,
  88                                         src, src_size, dst, &out_pos, dst_alloc_size);
  89         if (ret != LZMA_OK)
  90                 return -ENOBUFS;
  91
  92         *dst_size = out_pos;
  93         return 0;
  94 #else
  95         return -EPROTONOSUPPORT;
  96 #endif
  97 }
  98
  99 int compress_blob_lz4(const void *src, uint64_t src_size,
 100                       void *dst, size_t dst_alloc_size, size_t *dst_size) {
 101 #ifdef HAVE_LZ4
 102         int r;
 103
 104         assert(src);
 105         assert(src_size > 0);
 106         assert(dst);
 107         assert(dst_alloc_size > 0);
 108         assert(dst_size);
 109
 110         /* Returns < 0 if we couldn't compress the data or the
 111          * compressed result is longer than the original */
 112
 113         if (src_size < 9)
 114                 return -ENOBUFS;
 115
 116         r = LZ4_compress_limitedOutput(src, dst + 8, src_size, (int) dst_alloc_size - 8);
 117         if (r <= 0)
 118                 return -ENOBUFS;
 119
 120         *(le64_t*) dst = htole64(src_size);
 121         *dst_size = r + 8;
 122
 123         return 0;
 124 #else
 125         return -EPROTONOSUPPORT;
 126 #endif
 127 }
 128
 129
 130 int decompress_blob_xz(const void *src, uint64_t src_size,
 131                        void **dst, size_t *dst_alloc_size, size_t* dst_size, size_t dst_max) {
 132
 133 #ifdef HAVE_XZ
 134         _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
 135         lzma_ret ret;
 136         size_t space;
 137
 138         assert(src);
 139         assert(src_size > 0);
 140         assert(dst);
 141         assert(dst_alloc_size);
 142         assert(dst_size);
 143         assert(*dst_alloc_size == 0 || *dst);
 144
 145         ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
 146         if (ret != LZMA_OK)
 147                 return -ENOMEM;
 148
 149         space = MIN(src_size * 2, dst_max ?: (size_t) -1);
 150         if (!greedy_realloc(dst, dst_alloc_size, space, 1))
 151                 return -ENOMEM;
 152
 153         s.next_in = src;
 154         s.avail_in = src_size;
 155
 156         s.next_out = *dst;
 157         s.avail_out = space;
 158
 159         for (;;) {
 160                 size_t used;
 161
 162                 ret = lzma_code(&s, LZMA_FINISH);
 163
 164                 if (ret == LZMA_STREAM_END)
 165                         break;
 166                 else if (ret != LZMA_OK)
 167                         return -ENOMEM;
 168
 169                 if (dst_max > 0 && (space - s.avail_out) >= dst_max)
 170                         break;
 171                 else if (dst_max > 0 && space == dst_max)
 172                         return -ENOBUFS;
 173
 174                 used = space - s.avail_out;
 175                 space = MIN(2 * space, dst_max ?: (size_t) -1);
 176                 if (!greedy_realloc(dst, dst_alloc_size, space, 1))
 177                         return -ENOMEM;
 178
 179                 s.avail_out = space - used;
 180                 s.next_out = *dst + used;
 181         }
 182
 183         *dst_size = space - s.avail_out;
 184         return 0;
 185 #else
 186         return -EPROTONOSUPPORT;
 187 #endif
 188 }
 189
 190 int decompress_blob_lz4(const void *src, uint64_t src_size,
 191                         void **dst, size_t *dst_alloc_size, size_t* dst_size, size_t dst_max) {
 192
 193 #ifdef HAVE_LZ4
 194         char* out;
 195         int r, size; /* LZ4 uses int for size */
 196
 197         assert(src);
 198         assert(src_size > 0);
 199         assert(dst);
 200         assert(dst_alloc_size);
 201         assert(dst_size);
 202         assert(*dst_alloc_size == 0 || *dst);
 203
 204         if (src_size <= 8)
 205                 return -EBADMSG;
 206
 207         size = le64toh( *(le64_t*)src );
 208         if (size < 0 || (unsigned) size != le64toh(*(le64_t*)src))
 209                 return -EFBIG;
 210         if ((size_t) size > *dst_alloc_size) {
 211                 out = realloc(*dst, size);
 212                 if (!out)
 213                         return -ENOMEM;
 214                 *dst = out;
 215                 *dst_alloc_size = size;
 216         } else
 217                 out = *dst;
 218
 219         r = LZ4_decompress_safe(src + 8, out, src_size - 8, size);
 220         if (r < 0 || r != size)
 221                 return -EBADMSG;
 222
 223         *dst_size = size;
 224         return 0;
 225 #else
 226         return -EPROTONOSUPPORT;
 227 #endif
 228 }
 229
 230 int decompress_blob(int compression,
 231                     const void *src, uint64_t src_size,
 232                     void **dst, size_t *dst_alloc_size, size_t* dst_size, size_t dst_max) {
 233         if (compression == OBJECT_COMPRESSED_XZ)
 234                 return decompress_blob_xz(src, src_size,
 235                                           dst, dst_alloc_size, dst_size, dst_max);
 236         else if (compression == OBJECT_COMPRESSED_LZ4)
 237                 return decompress_blob_lz4(src, src_size,
 238                                            dst, dst_alloc_size, dst_size, dst_max);
 239         else
 240                 return -EBADMSG;
 241 }
 242
 243
 244 int decompress_startswith_xz(const void *src, uint64_t src_size,
 245                              void **buffer, size_t *buffer_size,
 246                              const void *prefix, size_t prefix_len,
 247                              uint8_t extra) {
 248
 249 #ifdef HAVE_XZ
 250         _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
 251         lzma_ret ret;
 252
 253         /* Checks whether the decompressed blob starts with the
 254          * mentioned prefix. The byte extra needs to follow the
 255          * prefix */
 256
 257         assert(src);
 258         assert(src_size > 0);
 259         assert(buffer);
 260         assert(buffer_size);
 261         assert(prefix);
 262         assert(*buffer_size == 0 || *buffer);
 263
 264         ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
 265         if (ret != LZMA_OK)
 266                 return -EBADMSG;
 267
 268         if (!(greedy_realloc(buffer, buffer_size, ALIGN_8(prefix_len + 1), 1)))
 269                 return -ENOMEM;
 270
 271         s.next_in = src;
 272         s.avail_in = src_size;
 273
 274         s.next_out = *buffer;
 275         s.avail_out = *buffer_size;
 276
 277         for (;;) {
 278                 ret = lzma_code(&s, LZMA_FINISH);
 279
 280                 if (ret != LZMA_STREAM_END && ret != LZMA_OK)
 281                         return -EBADMSG;
 282
 283                 if (*buffer_size - s.avail_out >= prefix_len + 1)
 284                         return memcmp(*buffer, prefix, prefix_len) == 0 &&
 285                                 ((const uint8_t*) *buffer)[prefix_len] == extra;
 286
 287                 if (ret == LZMA_STREAM_END)
 288                         return 0;
 289
 290                 s.avail_out += *buffer_size;
 291
 292                 if (!(greedy_realloc(buffer, buffer_size, *buffer_size * 2, 1)))
 293                         return -ENOMEM;
 294
 295                 s.next_out = *buffer + *buffer_size - s.avail_out;
 296         }
 297
 298 #else
 299         return -EPROTONOSUPPORT;
 300 #endif
 301 }
 302
 303 int decompress_startswith_lz4(const void *src, uint64_t src_size,
 304                               void **buffer, size_t *buffer_size,
 305                               const void *prefix, size_t prefix_len,
 306                               uint8_t extra) {
 307 #ifdef HAVE_LZ4
 308         /* Checks whether the decompressed blob starts with the
 309          * mentioned prefix. The byte extra needs to follow the
 310          * prefix */
 311
 312         int r;
 313         size_t size;
 314
 315         assert(src);
 316         assert(src_size > 0);
 317         assert(buffer);
 318         assert(buffer_size);
 319         assert(prefix);
 320         assert(*buffer_size == 0 || *buffer);
 321
 322         if (src_size <= 8)
 323                 return -EBADMSG;
 324
 325         if (!(greedy_realloc(buffer, buffer_size, ALIGN_8(prefix_len + 1), 1)))
 326                 return -ENOMEM;
 327
 328         r = LZ4_decompress_safe_partial(src + 8, *buffer, src_size - 8,
 329                                         prefix_len + 1, *buffer_size);
 330         if (r >= 0)
 331                 size = (unsigned) r;
 332         else {
 333                 /* lz4 always tries to decode full "sequence", so in
 334                  * pathological cases might need to decompress the
 335                  * full field. */
 336                 r = decompress_blob_lz4(src, src_size, buffer, buffer_size, &size, 0);
 337                 if (r < 0)
 338                         return r;
 339         }
 340
 341         if (size >= prefix_len + 1)
 342                 return memcmp(*buffer, prefix, prefix_len) == 0 &&
 343                         ((const uint8_t*) *buffer)[prefix_len] == extra;
 344         else
 345                 return 0;
 346
 347 #else
 348         return -EPROTONOSUPPORT;
 349 #endif
 350 }
 351
 352 int decompress_startswith(int compression,
 353                           const void *src, uint64_t src_size,
 354                           void **buffer, size_t *buffer_size,
 355                           const void *prefix, size_t prefix_len,
 356                           uint8_t extra) {
 357         if (compression == OBJECT_COMPRESSED_XZ)
 358                 return decompress_startswith_xz(src, src_size,
 359                                                 buffer, buffer_size,
 360                                                 prefix, prefix_len,
 361                                                 extra);
 362         else if (compression == OBJECT_COMPRESSED_LZ4)
 363                 return decompress_startswith_lz4(src, src_size,
 364                                                  buffer, buffer_size,
 365                                                  prefix, prefix_len,
 366                                                  extra);
 367         else
 368                 return -EBADMSG;
 369 }
 370
 371 int compress_stream_xz(int fdf, int fdt, uint64_t max_bytes) {
 372 #ifdef HAVE_XZ
 373         _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
 374         lzma_ret ret;
 375         uint8_t buf[BUFSIZ], out[BUFSIZ];
 376         lzma_action action = LZMA_RUN;
 377
 378         assert(fdf >= 0);
 379         assert(fdt >= 0);
 380
 381         ret = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_CRC64);
 382         if (ret != LZMA_OK) {
 383                 log_error("Failed to initialize XZ encoder: code %u", ret);
 384                 return -EINVAL;
 385         }
 386
 387         for (;;) {
 388                 if (s.avail_in == 0 && action == LZMA_RUN) {
 389                         size_t m = sizeof(buf);
 390                         ssize_t n;
 391
 392                         if (max_bytes != (uint64_t) -1 && (uint64_t) m > max_bytes)
 393                                 m = (size_t) max_bytes;
 394
 395                         n = read(fdf, buf, m);
 396                         if (n < 0)
 397                                 return -errno;
 398                         if (n == 0)
 399                                 action = LZMA_FINISH;
 400                         else {
 401                                 s.next_in = buf;
 402                                 s.avail_in = n;
 403
 404                                 if (max_bytes != (uint64_t) -1) {
 405                                         assert(max_bytes >= (uint64_t) n);
 406                                         max_bytes -= n;
 407                                 }
 408                         }
 409                 }
 410
 411                 if (s.avail_out == 0) {
 412                         s.next_out = out;
 413                         s.avail_out = sizeof(out);
 414                 }
 415
 416                 ret = lzma_code(&s, action);
 417                 if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
 418                         log_error("Compression failed: code %u", ret);
 419                         return -EBADMSG;
 420                 }
 421
 422                 if (s.avail_out == 0 || ret == LZMA_STREAM_END) {
 423                         ssize_t n, k;
 424
 425                         n = sizeof(out) - s.avail_out;
 426
 427                         k = loop_write(fdt, out, n, false);
 428                         if (k < 0)
 429                                 return k;
 430
 431                         if (ret == LZMA_STREAM_END) {
 432                                 log_debug("XZ compression finished (%"PRIu64" -> %"PRIu64" bytes, %.1f%%)",
 433                                           s.total_in, s.total_out,
 434                                           (double) s.total_out / s.total_in * 100);
 435
 436                                 return 0;
 437                         }
 438                 }
 439         }
 440 #else
 441         return -EPROTONOSUPPORT;
 442 #endif
 443 }
 444
 445 #define LZ4_BUFSIZE (512*1024u)
 446
 447 int compress_stream_lz4(int fdf, int fdt, uint64_t max_bytes) {
 448
 449 #ifdef HAVE_LZ4
 450         LZ4F_errorCode_t c;
 451         _cleanup_(LZ4F_freeCompressionContextp) LZ4F_compressionContext_t ctx = NULL;
 452         _cleanup_free_ char *buf = NULL;
 453         char *src = NULL;
 454         size_t size, n, total_in = 0, total_out, offset = 0, frame_size;
 455         struct stat st;
 456         int r;
 457         static const LZ4F_compressOptions_t options = {
 458                 .stableSrc = 1,
 459         };
 460         static const LZ4F_preferences_t preferences = {
 461                 .frameInfo.blockSizeID = 5,
 462         };
 463
 464         c = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
 465         if (LZ4F_isError(c))
 466                 return -ENOMEM;
 467
 468         if (fstat(fdf, &st) < 0)
 469                 return log_debug_errno(errno, "fstat() failed: %m");
 470
 471         frame_size = LZ4F_compressBound(LZ4_BUFSIZE, &preferences);
 472         size =  frame_size + 64*1024; /* add some space for header and trailer */
 473         buf = malloc(size);
 474         if (!buf)
 475                 return -ENOMEM;
 476
 477         n = offset = total_out = LZ4F_compressBegin(ctx, buf, size, &preferences);
 478         if (LZ4F_isError(n))
 479                 return -EINVAL;
 480
 481         src = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fdf, 0);
 482         if (src == MAP_FAILED)
 483                 return -errno;
 484
 485         log_debug("Buffer size is %zu bytes, header size %zu bytes.", size, n);
 486
 487         while (total_in < (size_t) st.st_size) {
 488                 ssize_t k;
 489
 490                 k = MIN(LZ4_BUFSIZE, st.st_size - total_in);
 491                 n = LZ4F_compressUpdate(ctx, buf + offset, size - offset,
 492                                         src + total_in, k, &options);
 493                 if (LZ4F_isError(n)) {
 494                         r = -ENOTRECOVERABLE;
 495                         goto cleanup;
 496                 }
 497
 498                 total_in += k;
 499                 offset += n;
 500                 total_out += n;
 501
 502                 if (max_bytes != (uint64_t) -1 && total_out > (size_t) max_bytes) {
 503                         log_debug("Compressed stream longer than %zd bytes", max_bytes);
 504                         return -EFBIG;
 505                 }
 506
 507                 if (size - offset < frame_size + 4) {
 508                         k = loop_write(fdt, buf, offset, false);
 509                         if (k < 0) {
 510                                 r = k;
 511                                 goto cleanup;
 512                         }
 513                         offset = 0;
 514                 }
 515         }
 516
 517         n = LZ4F_compressEnd(ctx, buf + offset, size - offset, &options);
 518         if (LZ4F_isError(n)) {
 519                 r = -ENOTRECOVERABLE;
 520                 goto cleanup;
 521         }
 522
 523         offset += n;
 524         total_out += n;
 525         r = loop_write(fdt, buf, offset, false);
 526         if (r < 0)
 527                 goto cleanup;
 528
 529         log_debug("LZ4 compression finished (%zu -> %zu bytes, %.1f%%)",
 530                   total_in, total_out,
 531                   (double) total_out / total_in * 100);
 532  cleanup:
 533         munmap(src, st.st_size);
 534         return r;
 535 #else
 536         return -EPROTONOSUPPORT;
 537 #endif
 538 }
 539
 540 int decompress_stream_xz(int fdf, int fdt, uint64_t max_bytes) {
 541
 542 #ifdef HAVE_XZ
 543         _cleanup_(lzma_end) lzma_stream s = LZMA_STREAM_INIT;
 544         lzma_ret ret;
 545
 546         uint8_t buf[BUFSIZ], out[BUFSIZ];
 547         lzma_action action = LZMA_RUN;
 548
 549         assert(fdf >= 0);
 550         assert(fdt >= 0);
 551
 552         ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
 553         if (ret != LZMA_OK) {
 554                 log_debug("Failed to initialize XZ decoder: code %u", ret);
 555                 return -ENOMEM;
 556         }
 557
 558         for (;;) {
 559                 if (s.avail_in == 0 && action == LZMA_RUN) {
 560                         ssize_t n;
 561
 562                         n = read(fdf, buf, sizeof(buf));
 563                         if (n < 0)
 564                                 return -errno;
 565                         if (n == 0)
 566                                 action = LZMA_FINISH;
 567                         else {
 568                                 s.next_in = buf;
 569                                 s.avail_in = n;
 570                         }
 571                 }
 572
 573                 if (s.avail_out == 0) {
 574                         s.next_out = out;
 575                         s.avail_out = sizeof(out);
 576                 }
 577
 578                 ret = lzma_code(&s, action);
 579                 if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
 580                         log_debug("Decompression failed: code %u", ret);
 581                         return -EBADMSG;
 582                 }
 583
 584                 if (s.avail_out == 0 || ret == LZMA_STREAM_END) {
 585                         ssize_t n, k;
 586
 587                         n = sizeof(out) - s.avail_out;
 588
 589                         if (max_bytes != (uint64_t) -1) {
 590                                 if (max_bytes < (uint64_t) n)
 591                                         return -EFBIG;
 592
 593                                 max_bytes -= n;
 594                         }
 595
 596                         k = loop_write(fdt, out, n, false);
 597                         if (k < 0)
 598                                 return k;
 599
 600                         if (ret == LZMA_STREAM_END) {
 601                                 log_debug("XZ decompression finished (%"PRIu64" -> %"PRIu64" bytes, %.1f%%)",
 602                                           s.total_in, s.total_out,
 603                                           (double) s.total_out / s.total_in * 100);
 604
 605                                 return 0;
 606                         }
 607                 }
 608         }
 609 #else
 610         log_debug("Cannot decompress file. Compiled without XZ support.");
 611         return -EPROTONOSUPPORT;
 612 #endif
 613 }
 614
 615 int decompress_stream_lz4(int in, int out, uint64_t max_bytes) {
 616 #ifdef HAVE_LZ4
 617         size_t c;
 618         _cleanup_(LZ4F_freeDecompressionContextp) LZ4F_decompressionContext_t ctx = NULL;
 619         _cleanup_free_ char *buf = NULL;
 620         char *src;
 621         struct stat st;
 622         int r = 0;
 623         size_t total_in = 0, total_out = 0;
 624
 625         c = LZ4F_createDecompressionContext(&ctx, LZ4F_VERSION);
 626         if (LZ4F_isError(c))
 627                 return -ENOMEM;
 628
 629         if (fstat(in, &st) < 0)
 630                 return log_debug_errno(errno, "fstat() failed: %m");
 631
 632         buf = malloc(LZ4_BUFSIZE);
 633         if (!buf)
 634                 return -ENOMEM;
 635
 636         src = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, in, 0);
 637         if (src == MAP_FAILED)
 638                 return -errno;
 639
 640         while (total_in < (size_t) st.st_size) {
 641                 size_t produced = LZ4_BUFSIZE;
 642                 size_t used = st.st_size - total_in;
 643
 644                 c = LZ4F_decompress(ctx, buf, &produced, src + total_in, &used, NULL);
 645                 if (LZ4F_isError(c)) {
 646                         r = -EBADMSG;
 647                         goto cleanup;
 648                 }
 649
 650                 total_in += used;
 651                 total_out += produced;
 652
 653                 if (max_bytes != (uint64_t) -1 && total_out > (size_t) max_bytes) {
 654                         log_debug("Decompressed stream longer than %zd bytes", max_bytes);
 655                         r = -EFBIG;
 656                         goto cleanup;
 657                 }
 658
 659                 r = loop_write(out, buf, produced, false);
 660                 if (r < 0)
 661                         goto cleanup;
 662         }
 663
 664         log_debug("LZ4 decompression finished (%zu -> %zu bytes, %.1f%%)",
 665                   total_in, total_out,
 666                   (double) total_out / total_in * 100);
 667  cleanup:
 668         munmap(src, st.st_size);
 669         return r;
 670 #else
 671         log_debug("Cannot decompress file. Compiled without LZ4 support.");
 672         return -EPROTONOSUPPORT;
 673 #endif
 674 }
 675
 676 int decompress_stream(const char *filename, int fdf, int fdt, uint64_t max_bytes) {
 677
 678         if (endswith(filename, ".lz4"))
 679                 return decompress_stream_lz4(fdf, fdt, max_bytes);
 680         else if (endswith(filename, ".xz"))
 681                 return decompress_stream_xz(fdf, fdt, max_bytes);
 682         else
 683                 return -EPROTONOSUPPORT;
 684 }