tools/mkimage.c

   1 /*
   2  * (C) Copyright 2008 Semihalf
   3  *
   4  * (C) Copyright 2000-2009
   5  * DENX Software Engineering
   6  * Wolfgang Denk, wd@denx.de
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include "mkimage.h"
  12 #include "imximage.h"
  13 #include <image.h>
  14 #include <version.h>
  15
  16 static void copy_file(int, const char *, int);
  17
  18 /* parameters initialized by core will be used by the image type code */
  19 static struct image_tool_params params = {
  20         .os = IH_OS_LINUX,
  21         .arch = IH_ARCH_PPC,
  22         .type = IH_TYPE_KERNEL,
  23         .comp = IH_COMP_GZIP,
  24         .dtc = MKIMAGE_DEFAULT_DTC_OPTIONS,
  25         .imagename = "",
  26         .imagename2 = "",
  27 };
  28
  29 static enum ih_category cur_category;
  30
  31 static int h_compare_category_name(const void *vtype1, const void *vtype2)
  32 {
  33         const int *type1 = vtype1;
  34         const int *type2 = vtype2;
  35         const char *name1 = genimg_get_cat_short_name(cur_category, *type1);
  36         const char *name2 = genimg_get_cat_short_name(cur_category, *type2);
  37
  38         return strcmp(name1, name2);
  39 }
  40
  41 static int show_valid_options(enum ih_category category)
  42 {
  43         int *order;
  44         int count;
  45         int item;
  46         int i;
  47
  48         count = genimg_get_cat_count(category);
  49         order = calloc(count, sizeof(*order));
  50         if (!order)
  51                 return -ENOMEM;
  52
  53         /* Sort the names in order of short name for easier reading */
  54         for (item = 0; item < count; item++)
  55                 order[item] = item;
  56         cur_category = category;
  57         qsort(order, count, sizeof(int), h_compare_category_name);
  58
  59         fprintf(stderr, "\nInvalid %s, supported are:\n",
  60                 genimg_get_cat_desc(category));
  61         for (i = 0; i < count; i++) {
  62                 item = order[i];
  63                 fprintf(stderr, "\t%-15s  %s\n",
  64                         genimg_get_cat_short_name(category, item),
  65                         genimg_get_cat_name(category, item));
  66         }
  67         fprintf(stderr, "\n");
  68         free(order);
  69
  70         return 0;
  71 }
  72
  73 static void usage(const char *msg)
  74 {
  75         fprintf(stderr, "Error: %s\n", msg);
  76         fprintf(stderr, "Usage: %s -l image\n"
  77                          "          -l ==> list image header information\n",
  78                 params.cmdname);
  79         fprintf(stderr,
  80                 "       %s [-x] -A arch -O os -T type -C comp -a addr -e ep -n name -d data_file[:data_file...] image\n"
  81                 "          -A ==> set architecture to 'arch'\n"
  82                 "          -O ==> set operating system to 'os'\n"
  83                 "          -T ==> set image type to 'type'\n"
  84                 "          -C ==> set compression type 'comp'\n"
  85                 "          -a ==> set load address to 'addr' (hex)\n"
  86                 "          -e ==> set entry point to 'ep' (hex)\n"
  87                 "          -n ==> set image name to 'name'\n"
  88                 "          -d ==> use image data from 'datafile'\n"
  89                 "          -x ==> set XIP (execute in place)\n",
  90                 params.cmdname);
  91         fprintf(stderr,
  92                 "       %s [-D dtc_options] [-f fit-image.its|-f auto|-F] [-b <dtb> [-b <dtb>]] [-i <ramdisk.cpio.gz>] fit-image\n"
  93                 "           <dtb> file is used with -f auto, it may occur multiple times.\n",
  94                 params.cmdname);
  95         fprintf(stderr,
  96                 "          -D => set all options for device tree compiler\n"
  97                 "          -f => input filename for FIT source\n"
  98                 "          -i => input filename for ramdisk file\n");
  99 #ifdef CONFIG_FIT_SIGNATURE
 100         fprintf(stderr,
 101                 "Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
 102                 "          -E => place data outside of the FIT structure\n"
 103                 "          -k => set directory containing private keys\n"
 104                 "          -K => write public keys to this .dtb file\n"
 105                 "          -c => add comment in signature node\n"
 106                 "          -F => re-sign existing FIT image\n"
 107                 "          -p => place external data at a static position\n"
 108                 "          -r => mark keys used as 'required' in dtb\n"
 109                 "          -N => engine to use for signing (pkcs11)\n");
 110 #else
 111         fprintf(stderr,
 112                 "Signing / verified boot not supported (CONFIG_FIT_SIGNATURE undefined)\n");
 113 #endif
 114         fprintf(stderr, "       %s -V ==> print version information and exit\n",
 115                 params.cmdname);
 116         fprintf(stderr, "Use -T to see a list of available image types\n");
 117
 118         exit(EXIT_FAILURE);
 119 }
 120
 121 static int add_content(int type, const char *fname)
 122 {
 123         struct content_info *cont;
 124
 125         cont = calloc(1, sizeof(*cont));
 126         if (!cont)
 127                 return -1;
 128         cont->type = type;
 129         cont->fname = fname;
 130         if (params.content_tail)
 131                 params.content_tail->next = cont;
 132         else
 133                 params.content_head = cont;
 134         params.content_tail = cont;
 135
 136         return 0;
 137 }
 138
 139 static void process_args(int argc, char **argv)
 140 {
 141         char *ptr;
 142         int type = IH_TYPE_INVALID;
 143         char *datafile = NULL;
 144         int opt;
 145
 146         while ((opt = getopt(argc, argv,
 147                              "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:N:p:O:rR:qsT:vVx")) != -1) {
 148                 switch (opt) {
 149                 case 'a':
 150                         params.addr = strtoull(optarg, &ptr, 16);
 151                         if (*ptr) {
 152                                 fprintf(stderr, "%s: invalid load address %s\n",
 153                                         params.cmdname, optarg);
 154                                 exit(EXIT_FAILURE);
 155                         }
 156                         break;
 157                 case 'A':
 158                         params.arch = genimg_get_arch_id(optarg);
 159                         if (params.arch < 0) {
 160                                 show_valid_options(IH_ARCH);
 161                                 usage("Invalid architecture");
 162                         }
 163                         break;
 164                 case 'b':
 165                         if (add_content(IH_TYPE_FLATDT, optarg)) {
 166                                 fprintf(stderr,
 167                                         "%s: Out of memory adding content '%s'",
 168                                         params.cmdname, optarg);
 169                                 exit(EXIT_FAILURE);
 170                         }
 171                         break;
 172                 case 'c':
 173                         params.comment = optarg;
 174                         break;
 175                 case 'C':
 176                         params.comp = genimg_get_comp_id(optarg);
 177                         if (params.comp < 0) {
 178                                 show_valid_options(IH_COMP);
 179                                 usage("Invalid compression type");
 180                         }
 181                         break;
 182                 case 'd':
 183                         params.datafile = optarg;
 184                         params.dflag = 1;
 185                         break;
 186                 case 'D':
 187                         params.dtc = optarg;
 188                         break;
 189                 case 'e':
 190                         params.ep = strtoull(optarg, &ptr, 16);
 191                         if (*ptr) {
 192                                 fprintf(stderr, "%s: invalid entry point %s\n",
 193                                         params.cmdname, optarg);
 194                                 exit(EXIT_FAILURE);
 195                         }
 196                         params.eflag = 1;
 197                         break;
 198                 case 'E':
 199                         params.external_data = true;
 200                         break;
 201                 case 'f':
 202                         datafile = optarg;
 203                         params.auto_its = !strcmp(datafile, "auto");
 204                         /* no break */
 205                 case 'F':
 206                         /*
 207                          * The flattened image tree (FIT) format
 208                          * requires a flattened device tree image type
 209                          */
 210                         params.type = IH_TYPE_FLATDT;
 211                         params.fflag = 1;
 212                         break;
 213                 case 'i':
 214                         params.fit_ramdisk = optarg;
 215                         break;
 216                 case 'k':
 217                         params.keydir = optarg;
 218                         break;
 219                 case 'K':
 220                         params.keydest = optarg;
 221                         break;
 222                 case 'l':
 223                         params.lflag = 1;
 224                         break;
 225                 case 'n':
 226                         params.imagename = optarg;
 227                         break;
 228                 case 'N':
 229                         params.engine_id = optarg;
 230                         break;
 231                 case 'O':
 232                         params.os = genimg_get_os_id(optarg);
 233                         if (params.os < 0) {
 234                                 show_valid_options(IH_OS);
 235                                 usage("Invalid operating system");
 236                         }
 237                         break;
 238                 case 'p':
 239                         params.external_offset = strtoull(optarg, &ptr, 16);
 240                         if (*ptr) {
 241                                 fprintf(stderr, "%s: invalid offset size %s\n",
 242                                         params.cmdname, optarg);
 243                                 exit(EXIT_FAILURE);
 244                         }
 245                         break;
 246                 case 'q':
 247                         params.quiet = 1;
 248                         break;
 249                 case 'r':
 250                         params.require_keys = 1;
 251                         break;
 252                 case 'R':
 253                         /*
 254                          * This entry is for the second configuration
 255                          * file, if only one is not enough.
 256                          */
 257                         params.imagename2 = optarg;
 258                         break;
 259                 case 's':
 260                         params.skipcpy = 1;
 261                         break;
 262                 case 'T':
 263                         type = genimg_get_type_id(optarg);
 264                         if (type < 0) {
 265                                 show_valid_options(IH_TYPE);
 266                                 usage("Invalid image type");
 267                         }
 268                         break;
 269                 case 'v':
 270                         params.vflag++;
 271                         break;
 272                 case 'V':
 273                         printf("mkimage version %s\n", PLAIN_VERSION);
 274                         exit(EXIT_SUCCESS);
 275                 case 'x':
 276                         params.xflag++;
 277                         break;
 278                 default:
 279                         usage("Invalid option");
 280                 }
 281         }
 282
 283         /* The last parameter is expected to be the imagefile */
 284         if (optind < argc)
 285                 params.imagefile = argv[optind];
 286
 287         /*
 288          * For auto-generated FIT images we need to know the image type to put
 289          * in the FIT, which is separate from the file's image type (which
 290          * will always be IH_TYPE_FLATDT in this case).
 291          */
 292         if (params.type == IH_TYPE_FLATDT) {
 293                 params.fit_image_type = type ? type : IH_TYPE_KERNEL;
 294                 /* For auto_its, datafile is always 'auto' */
 295                 if (!params.auto_its)
 296                         params.datafile = datafile;
 297                 else if (!params.datafile)
 298                         usage("Missing data file for auto-FIT (use -d)");
 299         } else if (type != IH_TYPE_INVALID) {
 300                 params.type = type;
 301         }
 302
 303         if (!params.imagefile)
 304                 usage("Missing output filename");
 305 }
 306
 307 int main(int argc, char **argv)
 308 {
 309         int ifd = -1;
 310         struct stat sbuf;
 311         char *ptr;
 312         int retval = 0;
 313         struct image_type_params *tparams = NULL;
 314         int pad_len = 0;
 315         int dfd;
 316
 317         params.cmdname = *argv;
 318         params.addr = 0;
 319         params.ep = 0;
 320
 321         process_args(argc, argv);
 322
 323         /* set tparams as per input type_id */
 324         tparams = imagetool_get_type(params.type);
 325         if (tparams == NULL) {
 326                 fprintf (stderr, "%s: unsupported type %s\n",
 327                         params.cmdname, genimg_get_type_name(params.type));
 328                 exit (EXIT_FAILURE);
 329         }
 330
 331         /*
 332          * check the passed arguments parameters meets the requirements
 333          * as per image type to be generated/listed
 334          */
 335         if (tparams->check_params)
 336                 if (tparams->check_params (&params))
 337                         usage("Bad parameters for image type");
 338
 339         if (!params.eflag) {
 340                 params.ep = params.addr;
 341                 /* If XIP, entry point must be after the U-Boot header */
 342                 if (params.xflag)
 343                         params.ep += tparams->header_size;
 344         }
 345
 346         if (params.fflag){
 347                 if (tparams->fflag_handle)
 348                         /*
 349                          * in some cases, some additional processing needs
 350                          * to be done if fflag is defined
 351                          *
 352                          * For ex. fit_handle_file for Fit file support
 353                          */
 354                         retval = tparams->fflag_handle(&params);
 355
 356                 if (retval != EXIT_SUCCESS)
 357                         exit (retval);
 358         }
 359
 360         if (params.lflag || params.fflag) {
 361                 ifd = open (params.imagefile, O_RDONLY|O_BINARY);
 362         } else {
 363                 ifd = open (params.imagefile,
 364                         O_RDWR|O_CREAT|O_TRUNC|O_BINARY, 0666);
 365         }
 366
 367         if (ifd < 0) {
 368                 fprintf (stderr, "%s: Can't open %s: %s\n",
 369                         params.cmdname, params.imagefile,
 370                         strerror(errno));
 371                 exit (EXIT_FAILURE);
 372         }
 373
 374         if (params.lflag || params.fflag) {
 375                 /*
 376                  * list header information of existing image
 377                  */
 378                 if (fstat(ifd, &sbuf) < 0) {
 379                         fprintf (stderr, "%s: Can't stat %s: %s\n",
 380                                 params.cmdname, params.imagefile,
 381                                 strerror(errno));
 382                         exit (EXIT_FAILURE);
 383                 }
 384
 385                 if ((unsigned)sbuf.st_size < tparams->header_size) {
 386                         fprintf (stderr,
 387                                 "%s: Bad size: \"%s\" is not valid image\n",
 388                                 params.cmdname, params.imagefile);
 389                         exit (EXIT_FAILURE);
 390                 }
 391
 392                 ptr = mmap(0, sbuf.st_size, PROT_READ, MAP_SHARED, ifd, 0);
 393                 if (ptr == MAP_FAILED) {
 394                         fprintf (stderr, "%s: Can't read %s: %s\n",
 395                                 params.cmdname, params.imagefile,
 396                                 strerror(errno));
 397                         exit (EXIT_FAILURE);
 398                 }
 399
 400                 /*
 401                  * scan through mkimage registry for all supported image types
 402                  * and verify the input image file header for match
 403                  * Print the image information for matched image type
 404                  * Returns the error code if not matched
 405                  */
 406                 retval = imagetool_verify_print_header(ptr, &sbuf,
 407                                 tparams, &params);
 408
 409                 (void) munmap((void *)ptr, sbuf.st_size);
 410                 (void) close (ifd);
 411
 412                 exit (retval);
 413         }
 414
 415         if ((params.type != IH_TYPE_MULTI) && (params.type != IH_TYPE_SCRIPT)) {
 416                 dfd = open(params.datafile, O_RDONLY | O_BINARY);
 417                 if (dfd < 0) {
 418                         fprintf(stderr, "%s: Can't open %s: %s\n",
 419                                 params.cmdname, params.datafile,
 420                                 strerror(errno));
 421                         exit(EXIT_FAILURE);
 422                 }
 423
 424                 if (fstat(dfd, &sbuf) < 0) {
 425                         fprintf(stderr, "%s: Can't stat %s: %s\n",
 426                                 params.cmdname, params.datafile,
 427                                 strerror(errno));
 428                         exit(EXIT_FAILURE);
 429                 }
 430
 431                 params.file_size = sbuf.st_size + tparams->header_size;
 432                 close(dfd);
 433         }
 434
 435         /*
 436          * In case there an header with a variable
 437          * length will be added, the corresponding
 438          * function is called. This is responsible to
 439          * allocate memory for the header itself.
 440          */
 441         if (tparams->vrec_header)
 442                 pad_len = tparams->vrec_header(&params, tparams);
 443         else
 444                 memset(tparams->hdr, 0, tparams->header_size);
 445
 446         if (write(ifd, tparams->hdr, tparams->header_size)
 447                                         != tparams->header_size) {
 448                 fprintf (stderr, "%s: Write error on %s: %s\n",
 449                         params.cmdname, params.imagefile, strerror(errno));
 450                 exit (EXIT_FAILURE);
 451         }
 452
 453         if (!params.skipcpy) {
 454                 if (params.type == IH_TYPE_MULTI ||
 455                     params.type == IH_TYPE_SCRIPT) {
 456                         char *file = params.datafile;
 457                         uint32_t size;
 458
 459                         for (;;) {
 460                                 char *sep = NULL;
 461
 462                                 if (file) {
 463                                         if ((sep = strchr(file, ':')) != NULL) {
 464                                                 *sep = '\0';
 465                                         }
 466
 467                                         if (stat (file, &sbuf) < 0) {
 468                                                 fprintf (stderr, "%s: Can't stat %s: %s\n",
 469                                                          params.cmdname, file, strerror(errno));
 470                                                 exit (EXIT_FAILURE);
 471                                         }
 472                                         size = cpu_to_uimage (sbuf.st_size);
 473                                 } else {
 474                                         size = 0;
 475                                 }
 476
 477                                 if (write(ifd, (char *)&size, sizeof(size)) != sizeof(size)) {
 478                                         fprintf (stderr, "%s: Write error on %s: %s\n",
 479                                                  params.cmdname, params.imagefile,
 480                                                  strerror(errno));
 481                                         exit (EXIT_FAILURE);
 482                                 }
 483
 484                                 if (!file) {
 485                                         break;
 486                                 }
 487
 488                                 if (sep) {
 489                                         *sep = ':';
 490                                         file = sep + 1;
 491                                 } else {
 492                                         file = NULL;
 493                                 }
 494                         }
 495
 496                         file = params.datafile;
 497
 498                         for (;;) {
 499                                 char *sep = strchr(file, ':');
 500                                 if (sep) {
 501                                         *sep = '\0';
 502                                         copy_file (ifd, file, 1);
 503                                         *sep++ = ':';
 504                                         file = sep;
 505                                 } else {
 506                                         copy_file (ifd, file, 0);
 507                                         break;
 508                                 }
 509                         }
 510                 } else if (params.type == IH_TYPE_PBLIMAGE) {
 511                         /* PBL has special Image format, implements its' own */
 512                         pbl_load_uboot(ifd, &params);
 513                 } else {
 514                         copy_file(ifd, params.datafile, pad_len);
 515                 }
 516                 if (params.type == IH_TYPE_FIRMWARE_IVT) {
 517                         /* Add alignment and IVT */
 518                         uint32_t aligned_filesize = (params.file_size + 0x1000
 519                                         - 1) & ~(0x1000 - 1);
 520                         flash_header_v2_t ivt_header = { { 0xd1, 0x2000, 0x40 },
 521                                         params.addr, 0, 0, 0, params.addr
 522                                                         + aligned_filesize
 523                                                         - tparams->header_size,
 524                                         params.addr + aligned_filesize
 525                                                         - tparams->header_size
 526                                                         + 0x20, 0 };
 527                         int i = params.file_size;
 528                         for (; i < aligned_filesize; i++) {
 529                                 if (write(ifd, &i, 1) != 1) {
 530                                         fprintf(stderr,
 531                                                         "%s: Write error on %s: %s\n",
 532                                                         params.cmdname,
 533                                                         params.imagefile,
 534                                                         strerror(errno));
 535                                         exit(EXIT_FAILURE);
 536                                 }
 537                         }
 538                         if (write(ifd, &ivt_header, sizeof(flash_header_v2_t))
 539                                         != sizeof(flash_header_v2_t)) {
 540                                 fprintf(stderr, "%s: Write error on %s: %s\n",
 541                                                 params.cmdname,
 542                                                 params.imagefile,
 543                                                 strerror(errno));
 544                                 exit(EXIT_FAILURE);
 545                         }
 546                 }
 547         }
 548
 549         /* We're a bit of paranoid */
 550 #if defined(_POSIX_SYNCHRONIZED_IO) && \
 551    !defined(__sun__) && \
 552    !defined(__FreeBSD__) && \
 553    !defined(__OpenBSD__) && \
 554    !defined(__APPLE__)
 555         (void) fdatasync (ifd);
 556 #else
 557         (void) fsync (ifd);
 558 #endif
 559
 560         if (fstat(ifd, &sbuf) < 0) {
 561                 fprintf (stderr, "%s: Can't stat %s: %s\n",
 562                         params.cmdname, params.imagefile, strerror(errno));
 563                 exit (EXIT_FAILURE);
 564         }
 565         params.file_size = sbuf.st_size;
 566
 567         ptr = mmap(0, sbuf.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, ifd, 0);
 568         if (ptr == MAP_FAILED) {
 569                 fprintf (stderr, "%s: Can't map %s: %s\n",
 570                         params.cmdname, params.imagefile, strerror(errno));
 571                 exit (EXIT_FAILURE);
 572         }
 573
 574         /* Setup the image header as per input image type*/
 575         if (tparams->set_header)
 576                 tparams->set_header (ptr, &sbuf, ifd, &params);
 577         else {
 578                 fprintf (stderr, "%s: Can't set header for %s: %s\n",
 579                         params.cmdname, tparams->name, strerror(errno));
 580                 exit (EXIT_FAILURE);
 581         }
 582
 583         /* Print the image information by processing image header */
 584         if (tparams->print_header)
 585                 tparams->print_header (ptr);
 586         else {
 587                 fprintf (stderr, "%s: Can't print header for %s: %s\n",
 588                         params.cmdname, tparams->name, strerror(errno));
 589                 exit (EXIT_FAILURE);
 590         }
 591
 592         (void) munmap((void *)ptr, sbuf.st_size);
 593
 594         /* We're a bit of paranoid */
 595 #if defined(_POSIX_SYNCHRONIZED_IO) && \
 596    !defined(__sun__) && \
 597    !defined(__FreeBSD__) && \
 598    !defined(__OpenBSD__) && \
 599    !defined(__APPLE__)
 600         (void) fdatasync (ifd);
 601 #else
 602         (void) fsync (ifd);
 603 #endif
 604
 605         if (close(ifd)) {
 606                 fprintf (stderr, "%s: Write error on %s: %s\n",
 607                         params.cmdname, params.imagefile, strerror(errno));
 608                 exit (EXIT_FAILURE);
 609         }
 610
 611         exit (EXIT_SUCCESS);
 612 }
 613
 614 static void
 615 copy_file (int ifd, const char *datafile, int pad)
 616 {
 617         int dfd;
 618         struct stat sbuf;
 619         unsigned char *ptr;
 620         int tail;
 621         int zero = 0;
 622         uint8_t zeros[4096];
 623         int offset = 0;
 624         int size;
 625         struct image_type_params *tparams = imagetool_get_type(params.type);
 626
 627         memset(zeros, 0, sizeof(zeros));
 628
 629         if (params.vflag) {
 630                 fprintf (stderr, "Adding Image %s\n", datafile);
 631         }
 632
 633         if ((dfd = open(datafile, O_RDONLY|O_BINARY)) < 0) {
 634                 fprintf (stderr, "%s: Can't open %s: %s\n",
 635                         params.cmdname, datafile, strerror(errno));
 636                 exit (EXIT_FAILURE);
 637         }
 638
 639         if (fstat(dfd, &sbuf) < 0) {
 640                 fprintf (stderr, "%s: Can't stat %s: %s\n",
 641                         params.cmdname, datafile, strerror(errno));
 642                 exit (EXIT_FAILURE);
 643         }
 644
 645         ptr = mmap(0, sbuf.st_size, PROT_READ, MAP_SHARED, dfd, 0);
 646         if (ptr == MAP_FAILED) {
 647                 fprintf (stderr, "%s: Can't read %s: %s\n",
 648                         params.cmdname, datafile, strerror(errno));
 649                 exit (EXIT_FAILURE);
 650         }
 651
 652         if (params.xflag) {
 653                 unsigned char *p = NULL;
 654                 /*
 655                  * XIP: do not append the image_header_t at the
 656                  * beginning of the file, but consume the space
 657                  * reserved for it.
 658                  */
 659
 660                 if ((unsigned)sbuf.st_size < tparams->header_size) {
 661                         fprintf (stderr,
 662                                 "%s: Bad size: \"%s\" is too small for XIP\n",
 663                                 params.cmdname, datafile);
 664                         exit (EXIT_FAILURE);
 665                 }
 666
 667                 for (p = ptr; p < ptr + tparams->header_size; p++) {
 668                         if ( *p != 0xff ) {
 669                                 fprintf (stderr,
 670                                         "%s: Bad file: \"%s\" has invalid buffer for XIP\n",
 671                                         params.cmdname, datafile);
 672                                 exit (EXIT_FAILURE);
 673                         }
 674                 }
 675
 676                 offset = tparams->header_size;
 677         }
 678
 679         size = sbuf.st_size - offset;
 680         if (write(ifd, ptr + offset, size) != size) {
 681                 fprintf (stderr, "%s: Write error on %s: %s\n",
 682                         params.cmdname, params.imagefile, strerror(errno));
 683                 exit (EXIT_FAILURE);
 684         }
 685
 686         tail = size % 4;
 687         if ((pad == 1) && (tail != 0)) {
 688
 689                 if (write(ifd, (char *)&zero, 4-tail) != 4-tail) {
 690                         fprintf (stderr, "%s: Write error on %s: %s\n",
 691                                 params.cmdname, params.imagefile,
 692                                 strerror(errno));
 693                         exit (EXIT_FAILURE);
 694                 }
 695         } else if (pad > 1) {
 696                 while (pad > 0) {
 697                         int todo = sizeof(zeros);
 698
 699                         if (todo > pad)
 700                                 todo = pad;
 701                         if (write(ifd, (char *)&zeros, todo) != todo) {
 702                                 fprintf(stderr, "%s: Write error on %s: %s\n",
 703                                         params.cmdname, params.imagefile,
 704                                         strerror(errno));
 705                                 exit(EXIT_FAILURE);
 706                         }
 707                         pad -= todo;
 708                 }
 709         }
 710
 711         (void) munmap((void *)ptr, sbuf.st_size);
 712         (void) close (dfd);
 713 }