archive-zip.c

   1 /*
   2  * Copyright (c) 2006 Rene Scharfe
   3  */
   4 #include "git-compat-util.h"
   5 #include "config.h"
   6 #include "archive.h"
   7 #include "gettext.h"
   8 #include "git-zlib.h"
   9 #include "hex.h"
  10 #include "streaming.h"
  11 #include "utf8.h"
  12 #include "object-store-ll.h"
  13 #include "userdiff.h"
  14 #include "write-or-die.h"
  15 #include "xdiff-interface.h"
  16 #include "date.h"
  17
  18 static int zip_date;
  19 static int zip_time;
  20
  21 /* We only care about the "buf" part here. */
  22 static struct strbuf zip_dir;
  23
  24 static uintmax_t zip_offset;
  25 static uint64_t zip_dir_entries;
  26
  27 static unsigned int max_creator_version;
  28
  29 #define ZIP_STREAM      (1 <<  3)
  30 #define ZIP_UTF8        (1 << 11)
  31
  32 enum zip_method {
  33         ZIP_METHOD_STORE = 0,
  34         ZIP_METHOD_DEFLATE = 8
  35 };
  36
  37 struct zip_local_header {
  38         unsigned char magic[4];
  39         unsigned char version[2];
  40         unsigned char flags[2];
  41         unsigned char compression_method[2];
  42         unsigned char mtime[2];
  43         unsigned char mdate[2];
  44         unsigned char crc32[4];
  45         unsigned char compressed_size[4];
  46         unsigned char size[4];
  47         unsigned char filename_length[2];
  48         unsigned char extra_length[2];
  49         unsigned char _end[1];
  50 };
  51
  52 struct zip_data_desc {
  53         unsigned char magic[4];
  54         unsigned char crc32[4];
  55         unsigned char compressed_size[4];
  56         unsigned char size[4];
  57         unsigned char _end[1];
  58 };
  59
  60 struct zip64_data_desc {
  61         unsigned char magic[4];
  62         unsigned char crc32[4];
  63         unsigned char compressed_size[8];
  64         unsigned char size[8];
  65         unsigned char _end[1];
  66 };
  67
  68 struct zip_dir_trailer {
  69         unsigned char magic[4];
  70         unsigned char disk[2];
  71         unsigned char directory_start_disk[2];
  72         unsigned char entries_on_this_disk[2];
  73         unsigned char entries[2];
  74         unsigned char size[4];
  75         unsigned char offset[4];
  76         unsigned char comment_length[2];
  77         unsigned char _end[1];
  78 };
  79
  80 struct zip_extra_mtime {
  81         unsigned char magic[2];
  82         unsigned char extra_size[2];
  83         unsigned char flags[1];
  84         unsigned char mtime[4];
  85         unsigned char _end[1];
  86 };
  87
  88 struct zip64_extra {
  89         unsigned char magic[2];
  90         unsigned char extra_size[2];
  91         unsigned char size[8];
  92         unsigned char compressed_size[8];
  93         unsigned char _end[1];
  94 };
  95
  96 struct zip64_dir_trailer {
  97         unsigned char magic[4];
  98         unsigned char record_size[8];
  99         unsigned char creator_version[2];
 100         unsigned char version[2];
 101         unsigned char disk[4];
 102         unsigned char directory_start_disk[4];
 103         unsigned char entries_on_this_disk[8];
 104         unsigned char entries[8];
 105         unsigned char size[8];
 106         unsigned char offset[8];
 107         unsigned char _end[1];
 108 };
 109
 110 struct zip64_dir_trailer_locator {
 111         unsigned char magic[4];
 112         unsigned char disk[4];
 113         unsigned char offset[8];
 114         unsigned char number_of_disks[4];
 115         unsigned char _end[1];
 116 };
 117
 118 /*
 119  * On ARM, padding is added at the end of the struct, so a simple
 120  * sizeof(struct ...) reports two bytes more than the payload size
 121  * we're interested in.
 122  */
 123 #define ZIP_LOCAL_HEADER_SIZE   offsetof(struct zip_local_header, _end)
 124 #define ZIP_DATA_DESC_SIZE      offsetof(struct zip_data_desc, _end)
 125 #define ZIP64_DATA_DESC_SIZE    offsetof(struct zip64_data_desc, _end)
 126 #define ZIP_DIR_HEADER_SIZE     offsetof(struct zip_dir_header, _end)
 127 #define ZIP_DIR_TRAILER_SIZE    offsetof(struct zip_dir_trailer, _end)
 128 #define ZIP_EXTRA_MTIME_SIZE    offsetof(struct zip_extra_mtime, _end)
 129 #define ZIP_EXTRA_MTIME_PAYLOAD_SIZE \
 130         (ZIP_EXTRA_MTIME_SIZE - offsetof(struct zip_extra_mtime, flags))
 131 #define ZIP64_EXTRA_SIZE        offsetof(struct zip64_extra, _end)
 132 #define ZIP64_EXTRA_PAYLOAD_SIZE \
 133         (ZIP64_EXTRA_SIZE - offsetof(struct zip64_extra, size))
 134 #define ZIP64_DIR_TRAILER_SIZE  offsetof(struct zip64_dir_trailer, _end)
 135 #define ZIP64_DIR_TRAILER_RECORD_SIZE \
 136         (ZIP64_DIR_TRAILER_SIZE - \
 137          offsetof(struct zip64_dir_trailer, creator_version))
 138 #define ZIP64_DIR_TRAILER_LOCATOR_SIZE \
 139         offsetof(struct zip64_dir_trailer_locator, _end)
 140
 141 static void copy_le16(unsigned char *dest, unsigned int n)
 142 {
 143         dest[0] = 0xff & n;
 144         dest[1] = 0xff & (n >> 010);
 145 }
 146
 147 static void copy_le32(unsigned char *dest, unsigned int n)
 148 {
 149         dest[0] = 0xff & n;
 150         dest[1] = 0xff & (n >> 010);
 151         dest[2] = 0xff & (n >> 020);
 152         dest[3] = 0xff & (n >> 030);
 153 }
 154
 155 static void copy_le64(unsigned char *dest, uint64_t n)
 156 {
 157         dest[0] = 0xff & n;
 158         dest[1] = 0xff & (n >> 010);
 159         dest[2] = 0xff & (n >> 020);
 160         dest[3] = 0xff & (n >> 030);
 161         dest[4] = 0xff & (n >> 040);
 162         dest[5] = 0xff & (n >> 050);
 163         dest[6] = 0xff & (n >> 060);
 164         dest[7] = 0xff & (n >> 070);
 165 }
 166
 167 static uint64_t clamp_max(uint64_t n, uint64_t max, int *clamped)
 168 {
 169         if (n <= max)
 170                 return n;
 171         *clamped = 1;
 172         return max;
 173 }
 174
 175 static void copy_le16_clamp(unsigned char *dest, uint64_t n, int *clamped)
 176 {
 177         copy_le16(dest, clamp_max(n, 0xffff, clamped));
 178 }
 179
 180 static void copy_le32_clamp(unsigned char *dest, uint64_t n, int *clamped)
 181 {
 182         copy_le32(dest, clamp_max(n, 0xffffffff, clamped));
 183 }
 184
 185 static int strbuf_add_le(struct strbuf *sb, size_t size, uintmax_t n)
 186 {
 187         while (size-- > 0) {
 188                 strbuf_addch(sb, n & 0xff);
 189                 n >>= 8;
 190         }
 191         return -!!n;
 192 }
 193
 194 static uint32_t clamp32(uintmax_t n)
 195 {
 196         const uintmax_t max = 0xffffffff;
 197         return (n < max) ? n : max;
 198 }
 199
 200 static void *zlib_deflate_raw(void *data, unsigned long size,
 201                               int compression_level,
 202                               unsigned long *compressed_size)
 203 {
 204         git_zstream stream;
 205         unsigned long maxsize;
 206         void *buffer;
 207         int result;
 208
 209         git_deflate_init_raw(&stream, compression_level);
 210         maxsize = git_deflate_bound(&stream, size);
 211         buffer = xmalloc(maxsize);
 212
 213         stream.next_in = data;
 214         stream.avail_in = size;
 215         stream.next_out = buffer;
 216         stream.avail_out = maxsize;
 217
 218         do {
 219                 result = git_deflate(&stream, Z_FINISH);
 220         } while (result == Z_OK);
 221
 222         if (result != Z_STREAM_END) {
 223                 free(buffer);
 224                 return NULL;
 225         }
 226
 227         git_deflate_end(&stream);
 228         *compressed_size = stream.total_out;
 229
 230         return buffer;
 231 }
 232
 233 static void write_zip_data_desc(unsigned long size,
 234                                 unsigned long compressed_size,
 235                                 unsigned long crc)
 236 {
 237         if (size >= 0xffffffff || compressed_size >= 0xffffffff) {
 238                 struct zip64_data_desc trailer;
 239                 copy_le32(trailer.magic, 0x08074b50);
 240                 copy_le32(trailer.crc32, crc);
 241                 copy_le64(trailer.compressed_size, compressed_size);
 242                 copy_le64(trailer.size, size);
 243                 write_or_die(1, &trailer, ZIP64_DATA_DESC_SIZE);
 244                 zip_offset += ZIP64_DATA_DESC_SIZE;
 245         } else {
 246                 struct zip_data_desc trailer;
 247                 copy_le32(trailer.magic, 0x08074b50);
 248                 copy_le32(trailer.crc32, crc);
 249                 copy_le32(trailer.compressed_size, compressed_size);
 250                 copy_le32(trailer.size, size);
 251                 write_or_die(1, &trailer, ZIP_DATA_DESC_SIZE);
 252                 zip_offset += ZIP_DATA_DESC_SIZE;
 253         }
 254 }
 255
 256 static void set_zip_header_data_desc(struct zip_local_header *header,
 257                                      unsigned long size,
 258                                      unsigned long compressed_size,
 259                                      unsigned long crc)
 260 {
 261         copy_le32(header->crc32, crc);
 262         copy_le32(header->compressed_size, compressed_size);
 263         copy_le32(header->size, size);
 264 }
 265
 266 static int has_only_ascii(const char *s)
 267 {
 268         for (;;) {
 269                 int c = *s++;
 270                 if (c == '\0')
 271                         return 1;
 272                 if (!isascii(c))
 273                         return 0;
 274         }
 275 }
 276
 277 static int entry_is_binary(struct index_state *istate, const char *path,
 278                            const void *buffer, size_t size)
 279 {
 280         struct userdiff_driver *driver = userdiff_find_by_path(istate, path);
 281         if (!driver)
 282                 driver = userdiff_find_by_name("default");
 283         if (driver->binary != -1)
 284                 return driver->binary;
 285         return buffer_is_binary(buffer, size);
 286 }
 287
 288 #define STREAM_BUFFER_SIZE (1024 * 16)
 289
 290 static int write_zip_entry(struct archiver_args *args,
 291                            const struct object_id *oid,
 292                            const char *path, size_t pathlen,
 293                            unsigned int mode,
 294                            void *buffer, unsigned long size)
 295 {
 296         struct zip_local_header header;
 297         uintmax_t offset = zip_offset;
 298         struct zip_extra_mtime extra;
 299         struct zip64_extra extra64;
 300         size_t header_extra_size = ZIP_EXTRA_MTIME_SIZE;
 301         int need_zip64_extra = 0;
 302         unsigned long attr2;
 303         unsigned long compressed_size;
 304         unsigned long crc;
 305         enum zip_method method;
 306         unsigned char *out;
 307         void *deflated = NULL;
 308         struct git_istream *stream = NULL;
 309         unsigned long flags = 0;
 310         int is_binary = -1;
 311         const char *path_without_prefix = path + args->baselen;
 312         unsigned int creator_version = 0;
 313         unsigned int version_needed = 10;
 314         size_t zip_dir_extra_size = ZIP_EXTRA_MTIME_SIZE;
 315         size_t zip64_dir_extra_payload_size = 0;
 316
 317         crc = crc32(0, NULL, 0);
 318
 319         if (!has_only_ascii(path)) {
 320                 if (is_utf8(path))
 321                         flags |= ZIP_UTF8;
 322                 else
 323                         warning(_("path is not valid UTF-8: %s"), path);
 324         }
 325
 326         if (pathlen > 0xffff) {
 327                 return error(_("path too long (%d chars, SHA1: %s): %s"),
 328                                 (int)pathlen, oid_to_hex(oid), path);
 329         }
 330
 331         if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 332                 method = ZIP_METHOD_STORE;
 333                 attr2 = 16;
 334                 out = NULL;
 335                 compressed_size = 0;
 336         } else if (S_ISREG(mode) || S_ISLNK(mode)) {
 337                 method = ZIP_METHOD_STORE;
 338                 attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) :
 339                         (mode & 0111) ? ((mode) << 16) : 0;
 340                 if (S_ISLNK(mode) || (mode & 0111))
 341                         creator_version = 0x0317;
 342                 if (S_ISREG(mode) && args->compression_level != 0 && size > 0)
 343                         method = ZIP_METHOD_DEFLATE;
 344
 345                 if (!buffer) {
 346                         enum object_type type;
 347                         stream = open_istream(args->repo, oid, &type, &size,
 348                                               NULL);
 349                         if (!stream)
 350                                 return error(_("cannot stream blob %s"),
 351                                              oid_to_hex(oid));
 352                         flags |= ZIP_STREAM;
 353                         out = NULL;
 354                 } else {
 355                         crc = crc32(crc, buffer, size);
 356                         is_binary = entry_is_binary(args->repo->index,
 357                                                     path_without_prefix,
 358                                                     buffer, size);
 359                         out = buffer;
 360                 }
 361                 compressed_size = (method == ZIP_METHOD_STORE) ? size : 0;
 362         } else {
 363                 return error(_("unsupported file mode: 0%o (SHA1: %s)"), mode,
 364                                 oid_to_hex(oid));
 365         }
 366
 367         if (creator_version > max_creator_version)
 368                 max_creator_version = creator_version;
 369
 370         if (buffer && method == ZIP_METHOD_DEFLATE) {
 371                 out = deflated = zlib_deflate_raw(buffer, size,
 372                                                   args->compression_level,
 373                                                   &compressed_size);
 374                 if (!out || compressed_size >= size) {
 375                         out = buffer;
 376                         method = ZIP_METHOD_STORE;
 377                         compressed_size = size;
 378                 }
 379         }
 380
 381         copy_le16(extra.magic, 0x5455);
 382         copy_le16(extra.extra_size, ZIP_EXTRA_MTIME_PAYLOAD_SIZE);
 383         extra.flags[0] = 1;     /* just mtime */
 384         copy_le32(extra.mtime, args->time);
 385
 386         if (size > 0xffffffff || compressed_size > 0xffffffff)
 387                 need_zip64_extra = 1;
 388         if (stream && size > 0x7fffffff)
 389                 need_zip64_extra = 1;
 390
 391         if (need_zip64_extra)
 392                 version_needed = 45;
 393
 394         copy_le32(header.magic, 0x04034b50);
 395         copy_le16(header.version, version_needed);
 396         copy_le16(header.flags, flags);
 397         copy_le16(header.compression_method, method);
 398         copy_le16(header.mtime, zip_time);
 399         copy_le16(header.mdate, zip_date);
 400         if (need_zip64_extra) {
 401                 set_zip_header_data_desc(&header, 0xffffffff, 0xffffffff, crc);
 402                 header_extra_size += ZIP64_EXTRA_SIZE;
 403         } else {
 404                 set_zip_header_data_desc(&header, size, compressed_size, crc);
 405         }
 406         copy_le16(header.filename_length, pathlen);
 407         copy_le16(header.extra_length, header_extra_size);
 408         write_or_die(1, &header, ZIP_LOCAL_HEADER_SIZE);
 409         zip_offset += ZIP_LOCAL_HEADER_SIZE;
 410         write_or_die(1, path, pathlen);
 411         zip_offset += pathlen;
 412         write_or_die(1, &extra, ZIP_EXTRA_MTIME_SIZE);
 413         zip_offset += ZIP_EXTRA_MTIME_SIZE;
 414         if (need_zip64_extra) {
 415                 copy_le16(extra64.magic, 0x0001);
 416                 copy_le16(extra64.extra_size, ZIP64_EXTRA_PAYLOAD_SIZE);
 417                 copy_le64(extra64.size, size);
 418                 copy_le64(extra64.compressed_size, compressed_size);
 419                 write_or_die(1, &extra64, ZIP64_EXTRA_SIZE);
 420                 zip_offset += ZIP64_EXTRA_SIZE;
 421         }
 422
 423         if (stream && method == ZIP_METHOD_STORE) {
 424                 unsigned char buf[STREAM_BUFFER_SIZE];
 425                 ssize_t readlen;
 426
 427                 for (;;) {
 428                         readlen = read_istream(stream, buf, sizeof(buf));
 429                         if (readlen <= 0)
 430                                 break;
 431                         crc = crc32(crc, buf, readlen);
 432                         if (is_binary == -1)
 433                                 is_binary = entry_is_binary(args->repo->index,
 434                                                             path_without_prefix,
 435                                                             buf, readlen);
 436                         write_or_die(1, buf, readlen);
 437                 }
 438                 close_istream(stream);
 439                 if (readlen)
 440                         return readlen;
 441
 442                 compressed_size = size;
 443                 zip_offset += compressed_size;
 444
 445                 write_zip_data_desc(size, compressed_size, crc);
 446         } else if (stream && method == ZIP_METHOD_DEFLATE) {
 447                 unsigned char buf[STREAM_BUFFER_SIZE];
 448                 ssize_t readlen;
 449                 git_zstream zstream;
 450                 int result;
 451                 size_t out_len;
 452                 unsigned char compressed[STREAM_BUFFER_SIZE * 2];
 453
 454                 git_deflate_init_raw(&zstream, args->compression_level);
 455
 456                 compressed_size = 0;
 457                 zstream.next_out = compressed;
 458                 zstream.avail_out = sizeof(compressed);
 459
 460                 for (;;) {
 461                         readlen = read_istream(stream, buf, sizeof(buf));
 462                         if (readlen <= 0)
 463                                 break;
 464                         crc = crc32(crc, buf, readlen);
 465                         if (is_binary == -1)
 466                                 is_binary = entry_is_binary(args->repo->index,
 467                                                             path_without_prefix,
 468                                                             buf, readlen);
 469
 470                         zstream.next_in = buf;
 471                         zstream.avail_in = readlen;
 472                         result = git_deflate(&zstream, 0);
 473                         if (result != Z_OK)
 474                                 die(_("deflate error (%d)"), result);
 475                         out_len = zstream.next_out - compressed;
 476
 477                         if (out_len > 0) {
 478                                 write_or_die(1, compressed, out_len);
 479                                 compressed_size += out_len;
 480                                 zstream.next_out = compressed;
 481                                 zstream.avail_out = sizeof(compressed);
 482                         }
 483
 484                 }
 485                 close_istream(stream);
 486                 if (readlen)
 487                         return readlen;
 488
 489                 zstream.next_in = buf;
 490                 zstream.avail_in = 0;
 491                 result = git_deflate(&zstream, Z_FINISH);
 492                 if (result != Z_STREAM_END)
 493                         die("deflate error (%d)", result);
 494
 495                 git_deflate_end(&zstream);
 496                 out_len = zstream.next_out - compressed;
 497                 write_or_die(1, compressed, out_len);
 498                 compressed_size += out_len;
 499                 zip_offset += compressed_size;
 500
 501                 write_zip_data_desc(size, compressed_size, crc);
 502         } else if (compressed_size > 0) {
 503                 write_or_die(1, out, compressed_size);
 504                 zip_offset += compressed_size;
 505         }
 506
 507         free(deflated);
 508
 509         if (compressed_size > 0xffffffff || size > 0xffffffff ||
 510             offset > 0xffffffff) {
 511                 if (compressed_size >= 0xffffffff)
 512                         zip64_dir_extra_payload_size += 8;
 513                 if (size >= 0xffffffff)
 514                         zip64_dir_extra_payload_size += 8;
 515                 if (offset >= 0xffffffff)
 516                         zip64_dir_extra_payload_size += 8;
 517                 zip_dir_extra_size += 2 + 2 + zip64_dir_extra_payload_size;
 518         }
 519
 520         strbuf_add_le(&zip_dir, 4, 0x02014b50); /* magic */
 521         strbuf_add_le(&zip_dir, 2, creator_version);
 522         strbuf_add_le(&zip_dir, 2, version_needed);
 523         strbuf_add_le(&zip_dir, 2, flags);
 524         strbuf_add_le(&zip_dir, 2, method);
 525         strbuf_add_le(&zip_dir, 2, zip_time);
 526         strbuf_add_le(&zip_dir, 2, zip_date);
 527         strbuf_add_le(&zip_dir, 4, crc);
 528         strbuf_add_le(&zip_dir, 4, clamp32(compressed_size));
 529         strbuf_add_le(&zip_dir, 4, clamp32(size));
 530         strbuf_add_le(&zip_dir, 2, pathlen);
 531         strbuf_add_le(&zip_dir, 2, zip_dir_extra_size);
 532         strbuf_add_le(&zip_dir, 2, 0);          /* comment length */
 533         strbuf_add_le(&zip_dir, 2, 0);          /* disk */
 534         strbuf_add_le(&zip_dir, 2, !is_binary);
 535         strbuf_add_le(&zip_dir, 4, attr2);
 536         strbuf_add_le(&zip_dir, 4, clamp32(offset));
 537         strbuf_add(&zip_dir, path, pathlen);
 538         strbuf_add(&zip_dir, &extra, ZIP_EXTRA_MTIME_SIZE);
 539         if (zip64_dir_extra_payload_size) {
 540                 strbuf_add_le(&zip_dir, 2, 0x0001);     /* magic */
 541                 strbuf_add_le(&zip_dir, 2, zip64_dir_extra_payload_size);
 542                 if (size >= 0xffffffff)
 543                         strbuf_add_le(&zip_dir, 8, size);
 544                 if (compressed_size >= 0xffffffff)
 545                         strbuf_add_le(&zip_dir, 8, compressed_size);
 546                 if (offset >= 0xffffffff)
 547                         strbuf_add_le(&zip_dir, 8, offset);
 548         }
 549         zip_dir_entries++;
 550
 551         return 0;
 552 }
 553
 554 static void write_zip64_trailer(void)
 555 {
 556         struct zip64_dir_trailer trailer64;
 557         struct zip64_dir_trailer_locator locator64;
 558
 559         copy_le32(trailer64.magic, 0x06064b50);
 560         copy_le64(trailer64.record_size, ZIP64_DIR_TRAILER_RECORD_SIZE);
 561         copy_le16(trailer64.creator_version, max_creator_version);
 562         copy_le16(trailer64.version, 45);
 563         copy_le32(trailer64.disk, 0);
 564         copy_le32(trailer64.directory_start_disk, 0);
 565         copy_le64(trailer64.entries_on_this_disk, zip_dir_entries);
 566         copy_le64(trailer64.entries, zip_dir_entries);
 567         copy_le64(trailer64.size, zip_dir.len);
 568         copy_le64(trailer64.offset, zip_offset);
 569
 570         copy_le32(locator64.magic, 0x07064b50);
 571         copy_le32(locator64.disk, 0);
 572         copy_le64(locator64.offset, zip_offset + zip_dir.len);
 573         copy_le32(locator64.number_of_disks, 1);
 574
 575         write_or_die(1, &trailer64, ZIP64_DIR_TRAILER_SIZE);
 576         write_or_die(1, &locator64, ZIP64_DIR_TRAILER_LOCATOR_SIZE);
 577 }
 578
 579 static void write_zip_trailer(const struct object_id *oid)
 580 {
 581         struct zip_dir_trailer trailer;
 582         int clamped = 0;
 583
 584         copy_le32(trailer.magic, 0x06054b50);
 585         copy_le16(trailer.disk, 0);
 586         copy_le16(trailer.directory_start_disk, 0);
 587         copy_le16_clamp(trailer.entries_on_this_disk, zip_dir_entries,
 588                         &clamped);
 589         copy_le16_clamp(trailer.entries, zip_dir_entries, &clamped);
 590         copy_le32(trailer.size, zip_dir.len);
 591         copy_le32_clamp(trailer.offset, zip_offset, &clamped);
 592         copy_le16(trailer.comment_length, oid ? the_hash_algo->hexsz : 0);
 593
 594         write_or_die(1, zip_dir.buf, zip_dir.len);
 595         if (clamped)
 596                 write_zip64_trailer();
 597         write_or_die(1, &trailer, ZIP_DIR_TRAILER_SIZE);
 598         if (oid)
 599                 write_or_die(1, oid_to_hex(oid), the_hash_algo->hexsz);
 600 }
 601
 602 static void dos_time(timestamp_t *timestamp, int *dos_date, int *dos_time)
 603 {
 604         time_t time;
 605         struct tm tm;
 606
 607         if (date_overflows(*timestamp))
 608                 die(_("timestamp too large for this system: %"PRItime),
 609                     *timestamp);
 610         time = (time_t)*timestamp;
 611         localtime_r(&time, &tm);
 612         *timestamp = time;
 613
 614         *dos_date = tm.tm_mday + (tm.tm_mon + 1) * 32 +
 615                     (tm.tm_year + 1900 - 1980) * 512;
 616         *dos_time = tm.tm_sec / 2 + tm.tm_min * 32 + tm.tm_hour * 2048;
 617 }
 618
 619 static int archive_zip_config(const char *var, const char *value,
 620                               const struct config_context *ctx UNUSED,
 621                               void *data UNUSED)
 622 {
 623         return userdiff_config(var, value);
 624 }
 625
 626 static int write_zip_archive(const struct archiver *ar UNUSED,
 627                              struct archiver_args *args)
 628 {
 629         int err;
 630
 631         git_config(archive_zip_config, NULL);
 632
 633         dos_time(&args->time, &zip_date, &zip_time);
 634
 635         strbuf_init(&zip_dir, 0);
 636
 637         err = write_archive_entries(args, write_zip_entry);
 638         if (!err)
 639                 write_zip_trailer(args->commit_oid);
 640
 641         strbuf_release(&zip_dir);
 642
 643         return err;
 644 }
 645
 646 static struct archiver zip_archiver = {
 647         .name = "zip",
 648         .write_archive = write_zip_archive,
 649         .flags = ARCHIVER_WANT_COMPRESSION_LEVELS|ARCHIVER_REMOTE,
 650 };
 651
 652 void init_zip_archiver(void)
 653 {
 654         register_archiver(&zip_archiver);
 655 }