Source

emacs / src / unexmacosx.c

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
/* Dump Emacs in Mach-O format for use on Mac OS X.
   Copyright (C) 2001-2011 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */

/* Contributed by Andrew Choi (akochoi@mac.com).  */

/* Documentation note.

   Consult the following documents/files for a description of the
   Mach-O format: the file loader.h, man pages for Mach-O and ld, old
   NEXTSTEP documents of the Mach-O format.  The tool otool dumps the
   mach header (-h option) and the load commands (-l option) in a
   Mach-O file.  The tool nm on Mac OS X displays the symbol table in
   a Mach-O file.  For examples of unexec for the Mach-O format, see
   the file unexnext.c in the GNU Emacs distribution, the file
   unexdyld.c in the Darwin port of GNU Emacs 20.7, and unexdyld.c in
   the Darwin port of XEmacs 21.1.  Also the Darwin Libc source
   contains the source code for malloc_freezedry and malloc_jumpstart.
   Read that to see what they do.  This file was written completely
   from scratch, making use of information from the above sources.  */

/* The Mac OS X implementation of unexec makes use of Darwin's `zone'
   memory allocator.  All calls to malloc, realloc, and free in Emacs
   are redirected to unexec_malloc, unexec_realloc, and unexec_free in
   this file.  When temacs is run, all memory requests are handled in
   the zone EmacsZone.  The Darwin memory allocator library calls
   maintain the data structures to manage this zone.  Dumping writes
   its contents to data segments of the executable file.  When emacs
   is run, the loader recreates the contents of the zone in memory.
   However since the initialization routine of the zone memory
   allocator is run again, this `zone' can no longer be used as a
   heap.  That is why emacs uses the ordinary malloc system call to
   allocate memory.  Also, when a block of memory needs to be
   reallocated and the new size is larger than the old one, a new
   block must be obtained by malloc and the old contents copied to
   it.  */

/* Peculiarity of the Mach-O files generated by ld in Mac OS X
   (possible causes of future bugs if changed).

   The file offset of the start of the __TEXT segment is zero.  Since
   the Mach header and load commands are located at the beginning of a
   Mach-O file, copying the contents of the __TEXT segment from the
   input file overwrites them in the output file.  Despite this,
   unexec works fine as written below because the segment load command
   for __TEXT appears, and is therefore processed, before all other
   load commands except the segment load command for __PAGEZERO, which
   remains unchanged.

   Although the file offset of the start of the __TEXT segment is
   zero, none of the sections it contains actually start there.  In
   fact, the earliest one starts a few hundred bytes beyond the end of
   the last load command.  The linker option -headerpad controls the
   minimum size of this padding.  Its setting can be changed in
   s/darwin.h.  A value of 0x690, e.g., leaves room for 30 additional
   load commands for the newly created __DATA segments (at 56 bytes
   each).  Unexec fails if there is not enough room for these new
   segments.

   The __TEXT segment contains the sections __text, __cstring,
   __picsymbol_stub, and __const and the __DATA segment contains the
   sections __data, __la_symbol_ptr, __nl_symbol_ptr, __dyld, __bss,
   and __common.  The other segments do not contain any sections.
   These sections are copied from the input file to the output file,
   except for __data, __bss, and __common, which are dumped from
   memory.  The types of the sections __bss and __common are changed
   from S_ZEROFILL to S_REGULAR.  Note that the number of sections and
   their relative order in the input and output files remain
   unchanged.  Otherwise all n_sect fields in the nlist records in the
   symbol table (specified by the LC_SYMTAB load command) will have to
   be changed accordingly.
*/

/* config.h #define:s malloc/realloc/free and then includes stdlib.h.
   We want the undefined versions, but if config.h includes stdlib.h
   with the #define:s in place, the prototypes will be wrong and we get
   warnings.  To prevent that, include stdlib.h before config.h.  */

#include <stdlib.h>
#include <config.h>
#undef malloc
#undef realloc
#undef free

#include "unexec.h"

#include <stdio.h>
#include <fcntl.h>
#include <stdarg.h>
#include <sys/types.h>
#include <unistd.h>
#include <mach/mach.h>
#include <mach-o/loader.h>
#include <mach-o/reloc.h>
#if defined (__ppc__)
#include <mach-o/ppc/reloc.h>
#endif
#ifdef HAVE_MALLOC_MALLOC_H
#include <malloc/malloc.h>
#else
#include <objc/malloc.h>
#endif

#include <assert.h>

#ifdef _LP64
#define mach_header			mach_header_64
#define segment_command			segment_command_64
#undef  VM_REGION_BASIC_INFO_COUNT
#define VM_REGION_BASIC_INFO_COUNT	VM_REGION_BASIC_INFO_COUNT_64
#undef  VM_REGION_BASIC_INFO
#define VM_REGION_BASIC_INFO		VM_REGION_BASIC_INFO_64
#undef  LC_SEGMENT
#define LC_SEGMENT			LC_SEGMENT_64
#define vm_region			vm_region_64
#define section				section_64
#undef MH_MAGIC
#define MH_MAGIC			MH_MAGIC_64
#endif

#define VERBOSE 1

/* Size of buffer used to copy data from the input file to the output
   file in function unexec_copy.  */
#define UNEXEC_COPY_BUFSZ 1024

/* Regions with memory addresses above this value are assumed to be
   mapped to dynamically loaded libraries and will not be dumped.  */
#define VM_DATA_TOP (20 * 1024 * 1024)

/* Type of an element on the list of regions to be dumped.  */
struct region_t {
  vm_address_t address;
  vm_size_t size;
  vm_prot_t protection;
  vm_prot_t max_protection;

  struct region_t *next;
};

/* Head and tail of the list of regions to be dumped.  */
static struct region_t *region_list_head = 0;
static struct region_t *region_list_tail = 0;

/* Pointer to array of load commands.  */
static struct load_command **lca;

/* Number of load commands.  */
static int nlc;

/* The highest VM address of segments loaded by the input file.
   Regions with addresses beyond this are assumed to be allocated
   dynamically and thus require dumping.  */
static vm_address_t infile_lc_highest_addr = 0;

/* The lowest file offset used by the all sections in the __TEXT
   segments.  This leaves room at the beginning of the file to store
   the Mach-O header.  Check this value against header size to ensure
   the added load commands for the new __DATA segments did not
   overwrite any of the sections in the __TEXT segment.  */
static unsigned long text_seg_lowest_offset = 0x10000000;

/* Mach header.  */
static struct mach_header mh;

/* Offset at which the next load command should be written.  */
static unsigned long curr_header_offset = sizeof (struct mach_header);

/* Offset at which the next segment should be written.  */
static unsigned long curr_file_offset = 0;

static unsigned long pagesize;
#define ROUNDUP_TO_PAGE_BOUNDARY(x)	(((x) + pagesize - 1) & ~(pagesize - 1))

static int infd, outfd;

static int in_dumped_exec = 0;

static malloc_zone_t *emacs_zone;

/* file offset of input file's data segment */
static off_t data_segment_old_fileoff = 0;

static struct segment_command *data_segment_scp;

static void unexec_error (const char *format, ...) NO_RETURN;

/* Read N bytes from infd into memory starting at address DEST.
   Return true if successful, false otherwise.  */
static int
unexec_read (void *dest, size_t n)
{
  return n == read (infd, dest, n);
}

/* Write COUNT bytes from memory starting at address SRC to outfd
   starting at offset DEST.  Return true if successful, false
   otherwise.  */
static int
unexec_write (off_t dest, const void *src, size_t count)
{
  if (lseek (outfd, dest, SEEK_SET) != dest)
    return 0;

  return write (outfd, src, count) == count;
}

/* Write COUNT bytes of zeros to outfd starting at offset DEST.
   Return true if successful, false otherwise.  */
static int
unexec_write_zero (off_t dest, size_t count)
{
  char buf[UNEXEC_COPY_BUFSZ];
  ssize_t bytes;

  memset (buf, 0, UNEXEC_COPY_BUFSZ);
  if (lseek (outfd, dest, SEEK_SET) != dest)
    return 0;

  while (count > 0)
    {
      bytes = count > UNEXEC_COPY_BUFSZ ? UNEXEC_COPY_BUFSZ : count;
      if (write (outfd, buf, bytes) != bytes)
	return 0;
      count -= bytes;
    }

  return 1;
}

/* Copy COUNT bytes from starting offset SRC in infd to starting
   offset DEST in outfd.  Return true if successful, false
   otherwise.  */
static int
unexec_copy (off_t dest, off_t src, ssize_t count)
{
  ssize_t bytes_read;
  ssize_t bytes_to_read;

  char buf[UNEXEC_COPY_BUFSZ];

  if (lseek (infd, src, SEEK_SET) != src)
    return 0;

  if (lseek (outfd, dest, SEEK_SET) != dest)
    return 0;

  while (count > 0)
    {
      bytes_to_read = count > UNEXEC_COPY_BUFSZ ? UNEXEC_COPY_BUFSZ : count;
      bytes_read = read (infd, buf, bytes_to_read);
      if (bytes_read <= 0)
	return 0;
      if (write (outfd, buf, bytes_read) != bytes_read)
	return 0;
      count -= bytes_read;
    }

  return 1;
}

/* Debugging and informational messages routines.  */

static void
unexec_error (const char *format, ...)
{
  va_list ap;

  va_start (ap, format);
  fprintf (stderr, "unexec: ");
  vfprintf (stderr, format, ap);
  fprintf (stderr, "\n");
  va_end (ap);
  exit (1);
}

static void
print_prot (vm_prot_t prot)
{
  if (prot == VM_PROT_NONE)
    printf ("none");
  else
    {
      putchar (prot & VM_PROT_READ ? 'r' : ' ');
      putchar (prot & VM_PROT_WRITE ? 'w' : ' ');
      putchar (prot & VM_PROT_EXECUTE ? 'x' : ' ');
      putchar (' ');
    }
}

static void
print_region (vm_address_t address, vm_size_t size, vm_prot_t prot,
	      vm_prot_t max_prot)
{
  printf ("%#10lx %#8lx ", (long) address, (long) size);
  print_prot (prot);
  putchar (' ');
  print_prot (max_prot);
  putchar ('\n');
}

static void
print_region_list (void)
{
  struct region_t *r;

  printf ("   address     size prot maxp\n");

  for (r = region_list_head; r; r = r->next)
    print_region (r->address, r->size, r->protection, r->max_protection);
}

static void
print_regions (void)
{
  task_t target_task = mach_task_self ();
  vm_address_t address = (vm_address_t) 0;
  vm_size_t size;
  struct vm_region_basic_info info;
  mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
  mach_port_t object_name;

  printf ("   address     size prot maxp\n");

  while (vm_region (target_task, &address, &size, VM_REGION_BASIC_INFO,
		    (vm_region_info_t) &info, &info_count, &object_name)
	 == KERN_SUCCESS && info_count == VM_REGION_BASIC_INFO_COUNT)
    {
      print_region (address, size, info.protection, info.max_protection);

      if (object_name != MACH_PORT_NULL)
	mach_port_deallocate (target_task, object_name);

      address += size;
    }
}

/* Build the list of regions that need to be dumped.  Regions with
   addresses above VM_DATA_TOP are omitted.  Adjacent regions with
   identical protection are merged.  Note that non-writable regions
   cannot be omitted because they some regions created at run time are
   read-only.  */
static void
build_region_list (void)
{
  task_t target_task = mach_task_self ();
  vm_address_t address = (vm_address_t) 0;
  vm_size_t size;
  struct vm_region_basic_info info;
  mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
  mach_port_t object_name;
  struct region_t *r;

#if VERBOSE
  printf ("--- List of All Regions ---\n");
  printf ("   address     size prot maxp\n");
#endif

  while (vm_region (target_task, &address, &size, VM_REGION_BASIC_INFO,
		    (vm_region_info_t) &info, &info_count, &object_name)
	 == KERN_SUCCESS && info_count == VM_REGION_BASIC_INFO_COUNT)
    {
      /* Done when we reach addresses of shared libraries, which are
	 loaded in high memory.  */
      if (address >= VM_DATA_TOP)
	break;

#if VERBOSE
      print_region (address, size, info.protection, info.max_protection);
#endif

      /* If a region immediately follows the previous one (the one
	 most recently added to the list) and has identical
	 protection, merge it with the latter.  Otherwise create a
	 new list element for it.  */
      if (region_list_tail
	  && info.protection == region_list_tail->protection
	  && info.max_protection == region_list_tail->max_protection
	  && region_list_tail->address + region_list_tail->size == address)
	{
	  region_list_tail->size += size;
	}
      else
	{
	  r = (struct region_t *) malloc (sizeof (struct region_t));

	  if (!r)
	    unexec_error ("cannot allocate region structure");

	  r->address = address;
	  r->size = size;
	  r->protection = info.protection;
	  r->max_protection = info.max_protection;

	  r->next = 0;
	  if (region_list_head == 0)
	    {
	      region_list_head = r;
	      region_list_tail = r;
	    }
	  else
	    {
	      region_list_tail->next = r;
	      region_list_tail = r;
	    }

	  /* Deallocate (unused) object name returned by
	     vm_region.  */
	  if (object_name != MACH_PORT_NULL)
	    mach_port_deallocate (target_task, object_name);
	}

      address += size;
    }

  printf ("--- List of Regions to be Dumped ---\n");
  print_region_list ();
}


#define MAX_UNEXEC_REGIONS 400

static int num_unexec_regions;
typedef struct {
  vm_range_t range;
  vm_size_t filesize;
} unexec_region_info;
static unexec_region_info unexec_regions[MAX_UNEXEC_REGIONS];

static void
unexec_regions_recorder (task_t task, void *rr, unsigned type,
			 vm_range_t *ranges, unsigned num)
{
  vm_address_t p;
  vm_size_t filesize;

  while (num && num_unexec_regions < MAX_UNEXEC_REGIONS)
    {
      /* Subtract the size of trailing null bytes from filesize.  It
	 can be smaller than vmsize in segment commands.  In such a
	 case, trailing bytes are initialized with zeros.  */
      for (p = ranges->address + ranges->size; p > ranges->address; p--)
      	if (*(((char *) p)-1))
      	  break;
      filesize = p - ranges->address;

      unexec_regions[num_unexec_regions].filesize = filesize;
      unexec_regions[num_unexec_regions++].range = *ranges;
      printf ("%#10lx (sz: %#8lx/%#8lx)\n", (long) (ranges->address),
	      (long) filesize, (long) (ranges->size));
      ranges++; num--;
    }
}

static kern_return_t
unexec_reader (task_t task, vm_address_t address, vm_size_t size, void **ptr)
{
  *ptr = (void *) address;
  return KERN_SUCCESS;
}

static void
find_emacs_zone_regions (void)
{
  num_unexec_regions = 0;

  emacs_zone->introspect->enumerator (mach_task_self (), 0,
				      MALLOC_PTR_REGION_RANGE_TYPE
				      | MALLOC_ADMIN_REGION_RANGE_TYPE,
				      (vm_address_t) emacs_zone,
				      unexec_reader,
				      unexec_regions_recorder);

  if (num_unexec_regions == MAX_UNEXEC_REGIONS)
    unexec_error ("find_emacs_zone_regions: too many regions");
}

static int
unexec_regions_sort_compare (const void *a, const void *b)
{
  vm_address_t aa = ((unexec_region_info *) a)->range.address;
  vm_address_t bb = ((unexec_region_info *) b)->range.address;

  if (aa < bb)
    return -1;
  else if (aa > bb)
    return 1;
  else
    return 0;
}

static void
unexec_regions_merge (void)
{
  int i, n;
  unexec_region_info r;
  vm_size_t padsize;

  qsort (unexec_regions, num_unexec_regions, sizeof (unexec_regions[0]),
	 &unexec_regions_sort_compare);
  n = 0;
  r = unexec_regions[0];
  padsize = r.range.address & (pagesize - 1);
  if (padsize)
    {
      r.range.address -= padsize;
      r.range.size += padsize;
      r.filesize += padsize;
    }
  for (i = 1; i < num_unexec_regions; i++)
    {
      if (r.range.address + r.range.size == unexec_regions[i].range.address
	  && r.range.size - r.filesize < 2 * pagesize)
	{
	  r.filesize = r.range.size + unexec_regions[i].filesize;
	  r.range.size += unexec_regions[i].range.size;
	}
      else
	{
	  unexec_regions[n++] = r;
	  r = unexec_regions[i];
	  padsize = r.range.address & (pagesize - 1);
	  if (padsize)
	    {
	      if ((unexec_regions[n-1].range.address
		   + unexec_regions[n-1].range.size) == r.range.address)
		unexec_regions[n-1].range.size -= padsize;

	      r.range.address -= padsize;
	      r.range.size += padsize;
	      r.filesize += padsize;
	    }
	}
    }
  unexec_regions[n++] = r;
  num_unexec_regions = n;
}


/* More informational messages routines.  */

static void
print_load_command_name (int lc)
{
  switch (lc)
    {
    case LC_SEGMENT:
#ifndef _LP64
      printf ("LC_SEGMENT       ");
#else
      printf ("LC_SEGMENT_64    ");
#endif
      break;
    case LC_LOAD_DYLINKER:
      printf ("LC_LOAD_DYLINKER ");
      break;
    case LC_LOAD_DYLIB:
      printf ("LC_LOAD_DYLIB    ");
      break;
    case LC_SYMTAB:
      printf ("LC_SYMTAB        ");
      break;
    case LC_DYSYMTAB:
      printf ("LC_DYSYMTAB      ");
      break;
    case LC_UNIXTHREAD:
      printf ("LC_UNIXTHREAD    ");
      break;
    case LC_PREBOUND_DYLIB:
      printf ("LC_PREBOUND_DYLIB");
      break;
    case LC_TWOLEVEL_HINTS:
      printf ("LC_TWOLEVEL_HINTS");
      break;
#ifdef LC_UUID
    case LC_UUID:
      printf ("LC_UUID          ");
      break;
#endif
#ifdef LC_DYLD_INFO
    case LC_DYLD_INFO:
      printf ("LC_DYLD_INFO     ");
      break;
    case LC_DYLD_INFO_ONLY:
      printf ("LC_DYLD_INFO_ONLY");
      break;
#endif
#ifdef LC_VERSION_MIN_MACOSX
    case LC_VERSION_MIN_MACOSX:
      printf ("LC_VERSION_MIN_MACOSX");
      break;
#endif
#ifdef LC_FUNCTION_STARTS
    case LC_FUNCTION_STARTS:
      printf ("LC_FUNCTION_STARTS");
      break;
#endif
    default:
      printf ("unknown          ");
    }
}

static void
print_load_command (struct load_command *lc)
{
  print_load_command_name (lc->cmd);
  printf ("%8d", lc->cmdsize);

  if (lc->cmd == LC_SEGMENT)
    {
      struct segment_command *scp;
      struct section *sectp;
      int j;

      scp = (struct segment_command *) lc;
      printf (" %-16.16s %#10lx %#8lx\n",
	      scp->segname, (long) (scp->vmaddr), (long) (scp->vmsize));

      sectp = (struct section *) (scp + 1);
      for (j = 0; j < scp->nsects; j++)
	{
	  printf ("                           %-16.16s %#10lx %#8lx\n",
		  sectp->sectname, (long) (sectp->addr), (long) (sectp->size));
	  sectp++;
	}
    }
  else
    printf ("\n");
}

/* Read header and load commands from input file.  Store the latter in
   the global array lca.  Store the total number of load commands in
   global variable nlc.  */
static void
read_load_commands (void)
{
  int i;

  if (!unexec_read (&mh, sizeof (struct mach_header)))
    unexec_error ("cannot read mach-o header");

  if (mh.magic != MH_MAGIC)
    unexec_error ("input file not in Mach-O format");

  if (mh.filetype != MH_EXECUTE)
    unexec_error ("input Mach-O file is not an executable object file");

#if VERBOSE
  printf ("--- Header Information ---\n");
  printf ("Magic = 0x%08x\n", mh.magic);
  printf ("CPUType = %d\n", mh.cputype);
  printf ("CPUSubType = %d\n", mh.cpusubtype);
  printf ("FileType = 0x%x\n", mh.filetype);
  printf ("NCmds = %d\n", mh.ncmds);
  printf ("SizeOfCmds = %d\n", mh.sizeofcmds);
  printf ("Flags = 0x%08x\n", mh.flags);
#endif

  nlc = mh.ncmds;
  lca = (struct load_command **) malloc (nlc * sizeof (struct load_command *));

  for (i = 0; i < nlc; i++)
    {
      struct load_command lc;
      /* Load commands are variable-size: so read the command type and
	 size first and then read the rest.  */
      if (!unexec_read (&lc, sizeof (struct load_command)))
        unexec_error ("cannot read load command");
      lca[i] = (struct load_command *) malloc (lc.cmdsize);
      memcpy (lca[i], &lc, sizeof (struct load_command));
      if (!unexec_read (lca[i] + 1, lc.cmdsize - sizeof (struct load_command)))
        unexec_error ("cannot read content of load command");
      if (lc.cmd == LC_SEGMENT)
	{
	  struct segment_command *scp = (struct segment_command *) lca[i];

	  if (scp->vmaddr + scp->vmsize > infile_lc_highest_addr)
	    infile_lc_highest_addr = scp->vmaddr + scp->vmsize;

	  if (strncmp (scp->segname, SEG_TEXT, 16) == 0)
	    {
	      struct section *sectp = (struct section *) (scp + 1);
	      int j;

	      for (j = 0; j < scp->nsects; j++)
		if (sectp->offset < text_seg_lowest_offset)
		  text_seg_lowest_offset = sectp->offset;
	    }
	}
    }

  printf ("Highest address of load commands in input file: %#8lx\n",
	  (unsigned long)infile_lc_highest_addr);

  printf ("Lowest offset of all sections in __TEXT segment: %#8lx\n",
	  text_seg_lowest_offset);

  printf ("--- List of Load Commands in Input File ---\n");
  printf ("# cmd              cmdsize name                address     size\n");

  for (i = 0; i < nlc; i++)
    {
      printf ("%1d ", i);
      print_load_command (lca[i]);
    }
}

/* Copy a LC_SEGMENT load command other than the __DATA segment from
   the input file to the output file, adjusting the file offset of the
   segment and the file offsets of sections contained in it.  */
static void
copy_segment (struct load_command *lc)
{
  struct segment_command *scp = (struct segment_command *) lc;
  unsigned long old_fileoff = scp->fileoff;
  struct section *sectp;
  int j;

  scp->fileoff = curr_file_offset;

  sectp = (struct section *) (scp + 1);
  for (j = 0; j < scp->nsects; j++)
    {
      sectp->offset += curr_file_offset - old_fileoff;
      sectp++;
    }

  printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)\n",
	  scp->segname, (long) (scp->fileoff), (long) (scp->filesize),
	  (long) (scp->vmsize), (long) (scp->vmaddr));

  if (!unexec_copy (scp->fileoff, old_fileoff, scp->filesize))
    unexec_error ("cannot copy segment from input to output file");
  curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (scp->filesize);

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write load command to header");

  curr_header_offset += lc->cmdsize;
}

/* Copy a LC_SEGMENT load command for the __DATA segment in the input
   file to the output file.  We assume that only one such segment load
   command exists in the input file and it contains the sections
   __data, __bss, __common, __la_symbol_ptr, __nl_symbol_ptr, and
   __dyld.  The first three of these should be dumped from memory and
   the rest should be copied from the input file.  Note that the
   sections __bss and __common contain no data in the input file
   because their flag fields have the value S_ZEROFILL.  Dumping these
   from memory makes it necessary to adjust file offset fields in
   subsequently dumped load commands.  Then, create new __DATA segment
   load commands for regions on the region list other than the one
   corresponding to the __DATA segment in the input file.  */
static void
copy_data_segment (struct load_command *lc)
{
  struct segment_command *scp = (struct segment_command *) lc;
  struct section *sectp;
  int j;
  unsigned long header_offset, old_file_offset;

  /* The new filesize of the segment is set to its vmsize because data
     blocks for segments must start at region boundaries.  Note that
     this may leave unused locations at the end of the segment data
     block because the total of the sizes of all sections in the
     segment is generally smaller than vmsize.  */
  scp->filesize = scp->vmsize;

  printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)\n",
	  scp->segname, curr_file_offset, (long)(scp->filesize),
	  (long)(scp->vmsize), (long) (scp->vmaddr));

  /* Offsets in the output file for writing the next section structure
     and segment data block, respectively.  */
  header_offset = curr_header_offset + sizeof (struct segment_command);

  sectp = (struct section *) (scp + 1);
  for (j = 0; j < scp->nsects; j++)
    {
      old_file_offset = sectp->offset;
      sectp->offset = sectp->addr - scp->vmaddr + curr_file_offset;
      /* The __data section is dumped from memory.  The __bss and
	 __common sections are also dumped from memory but their flag
	 fields require changing (from S_ZEROFILL to S_REGULAR).  The
	 other three kinds of sections are just copied from the input
	 file.  */
      if (strncmp (sectp->sectname, SECT_DATA, 16) == 0)
	{
	  if (!unexec_write (sectp->offset, (void *) sectp->addr, sectp->size))
	    unexec_error ("cannot write section %s", SECT_DATA);
	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))
	    unexec_error ("cannot write section %s's header", SECT_DATA);
	}
      else if (strncmp (sectp->sectname, SECT_COMMON, 16) == 0)
	{
	  sectp->flags = S_REGULAR;
	  if (!unexec_write (sectp->offset, (void *) sectp->addr, sectp->size))
	    unexec_error ("cannot write section %s", sectp->sectname);
	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))
	    unexec_error ("cannot write section %s's header", sectp->sectname);
	}
      else if (strncmp (sectp->sectname, SECT_BSS, 16) == 0)
	{
	  extern char *my_endbss_static;
	  unsigned long my_size;

	  sectp->flags = S_REGULAR;

	  /* Clear uninitialized local variables in statically linked
	     libraries.  In particular, function pointers stored by
	     libSystemStub.a, which is introduced in Mac OS X 10.4 for
	     binary compatibility with respect to long double, are
	     cleared so that they will be reinitialized when the
	     dumped binary is executed on other versions of OS.  */
	  my_size = (unsigned long)my_endbss_static - sectp->addr;
	  if (!(sectp->addr <= (unsigned long)my_endbss_static
		&& my_size <= sectp->size))
	    unexec_error ("my_endbss_static is not in section %s",
			  sectp->sectname);
	  if (!unexec_write (sectp->offset, (void *) sectp->addr, my_size))
	    unexec_error ("cannot write section %s", sectp->sectname);
	  if (!unexec_write_zero (sectp->offset + my_size,
				  sectp->size - my_size))
	    unexec_error ("cannot write section %s", sectp->sectname);
	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))
	    unexec_error ("cannot write section %s's header", sectp->sectname);
	}
      else if (strncmp (sectp->sectname, "__la_symbol_ptr", 16) == 0
	       || strncmp (sectp->sectname, "__nl_symbol_ptr", 16) == 0
	       || strncmp (sectp->sectname, "__got", 16) == 0
	       || strncmp (sectp->sectname, "__la_sym_ptr2", 16) == 0
	       || strncmp (sectp->sectname, "__dyld", 16) == 0
	       || strncmp (sectp->sectname, "__const", 16) == 0
	       || strncmp (sectp->sectname, "__cfstring", 16) == 0
	       || strncmp (sectp->sectname, "__gcc_except_tab", 16) == 0
	       || strncmp (sectp->sectname, "__program_vars", 16) == 0
	       || strncmp (sectp->sectname, "__objc_", 7) == 0)
	{
	  if (!unexec_copy (sectp->offset, old_file_offset, sectp->size))
	    unexec_error ("cannot copy section %s", sectp->sectname);
	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))
	    unexec_error ("cannot write section %s's header", sectp->sectname);
	}
      else
	unexec_error ("unrecognized section name in __DATA segment");

      printf ("        section %-16.16s at %#8lx - %#8lx (sz: %#8lx)\n",
	      sectp->sectname, (long) (sectp->offset),
	      (long) (sectp->offset + sectp->size), (long) (sectp->size));

      header_offset += sizeof (struct section);
      sectp++;
    }

  curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (scp->filesize);

  if (!unexec_write (curr_header_offset, scp, sizeof (struct segment_command)))
    unexec_error ("cannot write header of __DATA segment");
  curr_header_offset += lc->cmdsize;

  /* Create new __DATA segment load commands for regions on the region
     list that do not corresponding to any segment load commands in
     the input file.
  */
  for (j = 0; j < num_unexec_regions; j++)
    {
      struct segment_command sc;

      sc.cmd = LC_SEGMENT;
      sc.cmdsize = sizeof (struct segment_command);
      strncpy (sc.segname, SEG_DATA, 16);
      sc.vmaddr = unexec_regions[j].range.address;
      sc.vmsize = unexec_regions[j].range.size;
      sc.fileoff = curr_file_offset;
      sc.filesize = unexec_regions[j].filesize;
      sc.maxprot = VM_PROT_READ | VM_PROT_WRITE;
      sc.initprot = VM_PROT_READ | VM_PROT_WRITE;
      sc.nsects = 0;
      sc.flags = 0;

      printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)\n",
	      sc.segname, (long) (sc.fileoff), (long) (sc.filesize),
	      (long) (sc.vmsize), (long) (sc.vmaddr));

      if (!unexec_write (sc.fileoff, (void *) sc.vmaddr, sc.filesize))
	unexec_error ("cannot write new __DATA segment");
      curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (sc.filesize);

      if (!unexec_write (curr_header_offset, &sc, sc.cmdsize))
	unexec_error ("cannot write new __DATA segment's header");
      curr_header_offset += sc.cmdsize;
      mh.ncmds++;
    }
}

/* Copy a LC_SYMTAB load command from the input file to the output
   file, adjusting the file offset fields.  */
static void
copy_symtab (struct load_command *lc, long delta)
{
  struct symtab_command *stp = (struct symtab_command *) lc;

  stp->symoff += delta;
  stp->stroff += delta;

  printf ("Writing LC_SYMTAB command\n");

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write symtab command to header");

  curr_header_offset += lc->cmdsize;
}

/* Fix up relocation entries. */
static void
unrelocate (const char *name, off_t reloff, int nrel, vm_address_t base)
{
  int i, unreloc_count;
  struct relocation_info reloc_info;
  struct scattered_relocation_info *sc_reloc_info
    = (struct scattered_relocation_info *) &reloc_info;
  vm_address_t location;

  for (unreloc_count = 0, i = 0; i < nrel; i++)
    {
      if (lseek (infd, reloff, L_SET) != reloff)
	unexec_error ("unrelocate: %s:%d cannot seek to reloc_info", name, i);
      if (!unexec_read (&reloc_info, sizeof (reloc_info)))
	unexec_error ("unrelocate: %s:%d cannot read reloc_info", name, i);
      reloff += sizeof (reloc_info);

      if (sc_reloc_info->r_scattered == 0)
	switch (reloc_info.r_type)
	  {
	  case GENERIC_RELOC_VANILLA:
	    location = base + reloc_info.r_address;
	    if (location >= data_segment_scp->vmaddr
		&& location < (data_segment_scp->vmaddr
			       + data_segment_scp->vmsize))
	      {
		off_t src_off = data_segment_old_fileoff
		  + (location - data_segment_scp->vmaddr);
		off_t dst_off = data_segment_scp->fileoff
		  + (location - data_segment_scp->vmaddr);

		if (!unexec_copy (dst_off, src_off, 1 << reloc_info.r_length))
		  unexec_error ("unrelocate: %s:%d cannot copy original value",
				name, i);
		unreloc_count++;
	      }
	    break;
	  default:
	    unexec_error ("unrelocate: %s:%d cannot handle type = %d",
			  name, i, reloc_info.r_type);
	  }
      else
	switch (sc_reloc_info->r_type)
	  {
#if defined (__ppc__)
	  case PPC_RELOC_PB_LA_PTR:
	    /* nothing to do for prebound lazy pointer */
	    break;
#endif
	  default:
	    unexec_error ("unrelocate: %s:%d cannot handle scattered type = %d",
			  name, i, sc_reloc_info->r_type);
	  }
    }

  if (nrel > 0)
    printf ("Fixed up %d/%d %s relocation entries in data segment.\n",
	    unreloc_count, nrel, name);
}

#if __ppc64__
/* Rebase r_address in the relocation table.  */
static void
rebase_reloc_address (off_t reloff, int nrel, long linkedit_delta, long diff)
{
  int i;
  struct relocation_info reloc_info;
  struct scattered_relocation_info *sc_reloc_info
    = (struct scattered_relocation_info *) &reloc_info;

  for (i = 0; i < nrel; i++, reloff += sizeof (reloc_info))
    {
      if (lseek (infd, reloff - linkedit_delta, L_SET)
	  != reloff - linkedit_delta)
	unexec_error ("rebase_reloc_table: cannot seek to reloc_info");
      if (!unexec_read (&reloc_info, sizeof (reloc_info)))
	unexec_error ("rebase_reloc_table: cannot read reloc_info");

      if (sc_reloc_info->r_scattered == 0
	  && reloc_info.r_type == GENERIC_RELOC_VANILLA)
	{
	  reloc_info.r_address -= diff;
	  if (!unexec_write (reloff, &reloc_info, sizeof (reloc_info)))
	    unexec_error ("rebase_reloc_table: cannot write reloc_info");
	}
    }
}
#endif

/* Copy a LC_DYSYMTAB load command from the input file to the output
   file, adjusting the file offset fields.  */
static void
copy_dysymtab (struct load_command *lc, long delta)
{
  struct dysymtab_command *dstp = (struct dysymtab_command *) lc;
  vm_address_t base;

#ifdef _LP64
#if __ppc64__
  {
    int i;

    base = 0;
    for (i = 0; i < nlc; i++)
      if (lca[i]->cmd == LC_SEGMENT)
	{
	  struct segment_command *scp = (struct segment_command *) lca[i];

	  if (scp->vmaddr + scp->vmsize > 0x100000000
	      && (scp->initprot & VM_PROT_WRITE) != 0)
	    {
	      base = data_segment_scp->vmaddr;
	      break;
	    }
	}
  }
#else
  /* First writable segment address.  */
  base = data_segment_scp->vmaddr;
#endif
#else
  /* First segment address in the file (unless MH_SPLIT_SEGS set). */
  base = 0;
#endif

  unrelocate ("local", dstp->locreloff, dstp->nlocrel, base);
  unrelocate ("external", dstp->extreloff, dstp->nextrel, base);

  if (dstp->nextrel > 0) {
    dstp->extreloff += delta;
  }

  if (dstp->nlocrel > 0) {
    dstp->locreloff += delta;
  }

  if (dstp->nindirectsyms > 0)
    dstp->indirectsymoff += delta;

  printf ("Writing LC_DYSYMTAB command\n");

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write symtab command to header");

  curr_header_offset += lc->cmdsize;

#if __ppc64__
  /* Check if the relocation base needs to be changed.  */
  if (base == 0)
    {
      vm_address_t newbase = 0;
      int i;

      for (i = 0; i < num_unexec_regions; i++)
	if (unexec_regions[i].range.address + unexec_regions[i].range.size
	    > 0x100000000)
	  {
	    newbase = data_segment_scp->vmaddr;
	    break;
	  }

      if (newbase)
	{
	  rebase_reloc_address (dstp->locreloff, dstp->nlocrel, delta, newbase);
	  rebase_reloc_address (dstp->extreloff, dstp->nextrel, delta, newbase);
	}
    }
#endif
}

/* Copy a LC_TWOLEVEL_HINTS load command from the input file to the output
   file, adjusting the file offset fields.  */
static void
copy_twolevelhints (struct load_command *lc, long delta)
{
  struct twolevel_hints_command *tlhp = (struct twolevel_hints_command *) lc;

  if (tlhp->nhints > 0) {
    tlhp->offset += delta;
  }

  printf ("Writing LC_TWOLEVEL_HINTS command\n");

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write two level hint command to header");

  curr_header_offset += lc->cmdsize;
}

#ifdef LC_DYLD_INFO
/* Copy a LC_DYLD_INFO(_ONLY) load command from the input file to the output
   file, adjusting the file offset fields.  */
static void
copy_dyld_info (struct load_command *lc, long delta)
{
  struct dyld_info_command *dip = (struct dyld_info_command *) lc;

  if (dip->rebase_off > 0)
    dip->rebase_off += delta;
  if (dip->bind_off > 0)
    dip->bind_off += delta;
  if (dip->weak_bind_off > 0)
    dip->weak_bind_off += delta;
  if (dip->lazy_bind_off > 0)
    dip->lazy_bind_off += delta;
  if (dip->export_off > 0)
    dip->export_off += delta;

  printf ("Writing ");
  print_load_command_name (lc->cmd);
  printf (" command\n");

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write dyld info command to header");

  curr_header_offset += lc->cmdsize;
}
#endif

#ifdef LC_FUNCTION_STARTS
/* Copy a LC_FUNCTION_STARTS load command from the input file to the
   output file, adjusting the data offset field.  */
static void
copy_linkedit_data (struct load_command *lc, long delta)
{
  struct linkedit_data_command *ldp = (struct linkedit_data_command *) lc;

  if (ldp->dataoff > 0)
    ldp->dataoff += delta;

  printf ("Writing ");
  print_load_command_name (lc->cmd);
  printf (" command\n");

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write linkedit data command to header");

  curr_header_offset += lc->cmdsize;
}
#endif

/* Copy other kinds of load commands from the input file to the output
   file, ones that do not require adjustments of file offsets.  */
static void
copy_other (struct load_command *lc)
{
  printf ("Writing ");
  print_load_command_name (lc->cmd);
  printf (" command\n");

  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
    unexec_error ("cannot write symtab command to header");

  curr_header_offset += lc->cmdsize;
}

/* Loop through all load commands and dump them.  Then write the Mach
   header.  */
static void
dump_it (void)
{
  int i;
  long linkedit_delta = 0;

  printf ("--- Load Commands written to Output File ---\n");

  for (i = 0; i < nlc; i++)
    switch (lca[i]->cmd)
      {
      case LC_SEGMENT:
	{
	  struct segment_command *scp = (struct segment_command *) lca[i];
	  if (strncmp (scp->segname, SEG_DATA, 16) == 0)
	    {
	      /* save data segment file offset and segment_command for
		 unrelocate */
	      if (data_segment_old_fileoff)
		unexec_error ("cannot handle multiple DATA segments"
			      " in input file");
	      data_segment_old_fileoff = scp->fileoff;
	      data_segment_scp = scp;

	      copy_data_segment (lca[i]);
	    }
	  else
	    {
	      if (strncmp (scp->segname, SEG_LINKEDIT, 16) == 0)
		{
		  if (linkedit_delta)
		    unexec_error ("cannot handle multiple LINKEDIT segments"
				  " in input file");
		  linkedit_delta = curr_file_offset - scp->fileoff;
		}

	      copy_segment (lca[i]);
	    }
	}
	break;
      case LC_SYMTAB:
	copy_symtab (lca[i], linkedit_delta);
	break;
      case LC_DYSYMTAB:
	copy_dysymtab (lca[i], linkedit_delta);
	break;
      case LC_TWOLEVEL_HINTS:
	copy_twolevelhints (lca[i], linkedit_delta);
	break;
#ifdef LC_DYLD_INFO
      case LC_DYLD_INFO:
      case LC_DYLD_INFO_ONLY:
	copy_dyld_info (lca[i], linkedit_delta);
	break;
#endif
#ifdef LC_FUNCTION_STARTS
      case LC_FUNCTION_STARTS:
	copy_linkedit_data (lca[i], linkedit_delta);
	break;
#endif
      default:
	copy_other (lca[i]);
	break;
      }

  if (curr_header_offset > text_seg_lowest_offset)
    unexec_error ("not enough room for load commands for new __DATA segments");

  printf ("%ld unused bytes follow Mach-O header\n",
	  text_seg_lowest_offset - curr_header_offset);

  mh.sizeofcmds = curr_header_offset - sizeof (struct mach_header);
  if (!unexec_write (0, &mh, sizeof (struct mach_header)))
    unexec_error ("cannot write final header contents");
}

/* Take a snapshot of Emacs and make a Mach-O format executable file
   from it.  The file names of the output and input files are outfile
   and infile, respectively.  The three other parameters are
   ignored.  */
void
unexec (const char *outfile, const char *infile)
{
  if (in_dumped_exec)
    unexec_error ("Unexec from a dumped executable is not supported.");

  pagesize = getpagesize ();
  infd = open (infile, O_RDONLY, 0);
  if (infd < 0)
    {
      unexec_error ("cannot open input file `%s'", infile);
    }

  outfd = open (outfile, O_WRONLY | O_TRUNC | O_CREAT, 0755);
  if (outfd < 0)
    {
      close (infd);
      unexec_error ("cannot open output file `%s'", outfile);
    }

  build_region_list ();
  read_load_commands ();

  find_emacs_zone_regions ();
  unexec_regions_merge ();

  in_dumped_exec = 1;

  dump_it ();

  close (outfd);
}


void
unexec_init_emacs_zone (void)
{
  emacs_zone = malloc_create_zone (0, 0);
  malloc_set_zone_name (emacs_zone, "EmacsZone");
}

#ifndef MACOSX_MALLOC_MULT16
#define MACOSX_MALLOC_MULT16 1
#endif

typedef struct unexec_malloc_header {
  union {
    char c[8];
    size_t size;
  } u;
} unexec_malloc_header_t;

#if MACOSX_MALLOC_MULT16

#define ptr_in_unexec_regions(p) ((((vm_address_t) (p)) & 8) != 0)

#else

int
ptr_in_unexec_regions (void *ptr)
{
  int i;

  for (i = 0; i < num_unexec_regions; i++)
    if ((vm_address_t) ptr - unexec_regions[i].range.address
	< unexec_regions[i].range.size)
      return 1;

  return 0;
}

#endif

void *
unexec_malloc (size_t size)
{
  if (in_dumped_exec)
    {
      void *p;

      p = malloc (size);
#if MACOSX_MALLOC_MULT16
      assert (((vm_address_t) p % 16) == 0);
#endif
      return p;
    }
  else
    {
      unexec_malloc_header_t *ptr;

      ptr = (unexec_malloc_header_t *)
	malloc_zone_malloc (emacs_zone, size + sizeof (unexec_malloc_header_t));
      ptr->u.size = size;
      ptr++;
#if MACOSX_MALLOC_MULT16
      assert (((vm_address_t) ptr % 16) == 8);
#endif
      return (void *) ptr;
    }
}

void *
unexec_realloc (void *old_ptr, size_t new_size)
{
  if (in_dumped_exec)
    {
      void *p;

      if (ptr_in_unexec_regions (old_ptr))
	{
	  size_t old_size = ((unexec_malloc_header_t *) old_ptr)[-1].u.size;
	  size_t size = new_size > old_size ? old_size : new_size;

	  p = (size_t *) malloc (new_size);
	  if (size)
	    memcpy (p, old_ptr, size);
	}
      else
	{
	  p = realloc (old_ptr, new_size);
	}
#if MACOSX_MALLOC_MULT16
      assert (((vm_address_t) p % 16) == 0);
#endif
      return p;
    }
  else
    {
      unexec_malloc_header_t *ptr;

      ptr = (unexec_malloc_header_t *)
	malloc_zone_realloc (emacs_zone, (unexec_malloc_header_t *) old_ptr - 1,
			     new_size + sizeof (unexec_malloc_header_t));
      ptr->u.size = new_size;
      ptr++;
#if MACOSX_MALLOC_MULT16
      assert (((vm_address_t) ptr % 16) == 8);
#endif
      return (void *) ptr;
    }
}

void
unexec_free (void *ptr)
{
  if (ptr == NULL)
    return;
  if (in_dumped_exec)
    {
      if (!ptr_in_unexec_regions (ptr))
	free (ptr);
    }
  else
    malloc_zone_free (emacs_zone, (unexec_malloc_header_t *) ptr - 1);
}