xref: /openbmc/u-boot/tools/mkimage.c (revision 8eef803a) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2008 Semihalf
4  *
5  * (C) Copyright 2000-2009
6  * DENX Software Engineering
7  * Wolfgang Denk, wd@denx.de
8  */
9 
10 #include "mkimage.h"
11 #include "imximage.h"
12 #include <image.h>
13 #include <version.h>
14 
15 static void copy_file(int, const char *, int);
16 
17 /* parameters initialized by core will be used by the image type code */
18 static struct image_tool_params params = {
19 	.os = IH_OS_LINUX,
20 	.arch = IH_ARCH_PPC,
21 	.type = IH_TYPE_KERNEL,
22 	.comp = IH_COMP_GZIP,
23 	.dtc = MKIMAGE_DEFAULT_DTC_OPTIONS,
24 	.imagename = "",
25 	.imagename2 = "",
26 };
27 
28 static enum ih_category cur_category;
29 
30 static int h_compare_category_name(const void *vtype1, const void *vtype2)
31 {
32 	const int *type1 = vtype1;
33 	const int *type2 = vtype2;
34 	const char *name1 = genimg_get_cat_short_name(cur_category, *type1);
35 	const char *name2 = genimg_get_cat_short_name(cur_category, *type2);
36 
37 	return strcmp(name1, name2);
38 }
39 
40 static int show_valid_options(enum ih_category category)
41 {
42 	int *order;
43 	int count;
44 	int item;
45 	int i;
46 
47 	count = genimg_get_cat_count(category);
48 	order = calloc(count, sizeof(*order));
49 	if (!order)
50 		return -ENOMEM;
51 
52 	/* Sort the names in order of short name for easier reading */
53 	for (item = 0; item < count; item++)
54 		order[item] = item;
55 	cur_category = category;
56 	qsort(order, count, sizeof(int), h_compare_category_name);
57 
58 	fprintf(stderr, "\nInvalid %s, supported are:\n",
59 		genimg_get_cat_desc(category));
60 	for (i = 0; i < count; i++) {
61 		item = order[i];
62 		fprintf(stderr, "\t%-15s  %s\n",
63 			genimg_get_cat_short_name(category, item),
64 			genimg_get_cat_name(category, item));
65 	}
66 	fprintf(stderr, "\n");
67 	free(order);
68 
69 	return 0;
70 }
71 
72 static void usage(const char *msg)
73 {
74 	fprintf(stderr, "Error: %s\n", msg);
75 	fprintf(stderr, "Usage: %s -l image\n"
76 			 "          -l ==> list image header information\n",
77 		params.cmdname);
78 	fprintf(stderr,
79 		"       %s [-x] -A arch -O os -T type -C comp -a addr -e ep -n name -d data_file[:data_file...] image\n"
80 		"          -A ==> set architecture to 'arch'\n"
81 		"          -O ==> set operating system to 'os'\n"
82 		"          -T ==> set image type to 'type'\n"
83 		"          -C ==> set compression type 'comp'\n"
84 		"          -a ==> set load address to 'addr' (hex)\n"
85 		"          -e ==> set entry point to 'ep' (hex)\n"
86 		"          -n ==> set image name to 'name'\n"
87 		"          -d ==> use image data from 'datafile'\n"
88 		"          -x ==> set XIP (execute in place)\n",
89 		params.cmdname);
90 	fprintf(stderr,
91 		"       %s [-D dtc_options] [-f fit-image.its|-f auto|-F] [-b <dtb> [-b <dtb>]] [-i <ramdisk.cpio.gz>] fit-image\n"
92 		"           <dtb> file is used with -f auto, it may occur multiple times.\n",
93 		params.cmdname);
94 	fprintf(stderr,
95 		"          -D => set all options for device tree compiler\n"
96 		"          -f => input filename for FIT source\n"
97 		"          -i => input filename for ramdisk file\n");
98 #ifdef CONFIG_FIT_SIGNATURE
99 	fprintf(stderr,
100 		"Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
101 		"          -E => place data outside of the FIT structure\n"
102 		"          -k => set directory containing private keys\n"
103 		"          -K => write public keys to this .dtb file\n"
104 		"          -c => add comment in signature node\n"
105 		"          -F => re-sign existing FIT image\n"
106 		"          -p => place external data at a static position\n"
107 		"          -r => mark keys used as 'required' in dtb\n"
108 		"          -N => engine to use for signing (pkcs11)\n");
109 #else
110 	fprintf(stderr,
111 		"Signing / verified boot not supported (CONFIG_FIT_SIGNATURE undefined)\n");
112 #endif
113 	fprintf(stderr, "       %s -V ==> print version information and exit\n",
114 		params.cmdname);
115 	fprintf(stderr, "Use '-T list' to see a list of available image types\n");
116 
117 	exit(EXIT_FAILURE);
118 }
119 
120 static int add_content(int type, const char *fname)
121 {
122 	struct content_info *cont;
123 
124 	cont = calloc(1, sizeof(*cont));
125 	if (!cont)
126 		return -1;
127 	cont->type = type;
128 	cont->fname = fname;
129 	if (params.content_tail)
130 		params.content_tail->next = cont;
131 	else
132 		params.content_head = cont;
133 	params.content_tail = cont;
134 
135 	return 0;
136 }
137 
138 static void process_args(int argc, char **argv)
139 {
140 	char *ptr;
141 	int type = IH_TYPE_INVALID;
142 	char *datafile = NULL;
143 	int opt;
144 
145 	while ((opt = getopt(argc, argv,
146 			     "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:N:p:O:rR:qsT:vVx")) != -1) {
147 		switch (opt) {
148 		case 'a':
149 			params.addr = strtoull(optarg, &ptr, 16);
150 			if (*ptr) {
151 				fprintf(stderr, "%s: invalid load address %s\n",
152 					params.cmdname, optarg);
153 				exit(EXIT_FAILURE);
154 			}
155 			break;
156 		case 'A':
157 			params.arch = genimg_get_arch_id(optarg);
158 			if (params.arch < 0) {
159 				show_valid_options(IH_ARCH);
160 				usage("Invalid architecture");
161 			}
162 			break;
163 		case 'b':
164 			if (add_content(IH_TYPE_FLATDT, optarg)) {
165 				fprintf(stderr,
166 					"%s: Out of memory adding content '%s'",
167 					params.cmdname, optarg);
168 				exit(EXIT_FAILURE);
169 			}
170 			break;
171 		case 'c':
172 			params.comment = optarg;
173 			break;
174 		case 'C':
175 			params.comp = genimg_get_comp_id(optarg);
176 			if (params.comp < 0) {
177 				show_valid_options(IH_COMP);
178 				usage("Invalid compression type");
179 			}
180 			break;
181 		case 'd':
182 			params.datafile = optarg;
183 			params.dflag = 1;
184 			break;
185 		case 'D':
186 			params.dtc = optarg;
187 			break;
188 		case 'e':
189 			params.ep = strtoull(optarg, &ptr, 16);
190 			if (*ptr) {
191 				fprintf(stderr, "%s: invalid entry point %s\n",
192 					params.cmdname, optarg);
193 				exit(EXIT_FAILURE);
194 			}
195 			params.eflag = 1;
196 			break;
197 		case 'E':
198 			params.external_data = true;
199 			break;
200 		case 'f':
201 			datafile = optarg;
202 			params.auto_its = !strcmp(datafile, "auto");
203 			/* no break */
204 		case 'F':
205 			/*
206 			 * The flattened image tree (FIT) format
207 			 * requires a flattened device tree image type
208 			 */
209 			params.type = IH_TYPE_FLATDT;
210 			params.fflag = 1;
211 			break;
212 		case 'i':
213 			params.fit_ramdisk = optarg;
214 			break;
215 		case 'k':
216 			params.keydir = optarg;
217 			break;
218 		case 'K':
219 			params.keydest = optarg;
220 			break;
221 		case 'l':
222 			params.lflag = 1;
223 			break;
224 		case 'n':
225 			params.imagename = optarg;
226 			break;
227 		case 'N':
228 			params.engine_id = optarg;
229 			break;
230 		case 'O':
231 			params.os = genimg_get_os_id(optarg);
232 			if (params.os < 0) {
233 				show_valid_options(IH_OS);
234 				usage("Invalid operating system");
235 			}
236 			break;
237 		case 'p':
238 			params.external_offset = strtoull(optarg, &ptr, 16);
239 			if (*ptr) {
240 				fprintf(stderr, "%s: invalid offset size %s\n",
241 					params.cmdname, optarg);
242 				exit(EXIT_FAILURE);
243 			}
244 			break;
245 		case 'q':
246 			params.quiet = 1;
247 			break;
248 		case 'r':
249 			params.require_keys = 1;
250 			break;
251 		case 'R':
252 			/*
253 			 * This entry is for the second configuration
254 			 * file, if only one is not enough.
255 			 */
256 			params.imagename2 = optarg;
257 			break;
258 		case 's':
259 			params.skipcpy = 1;
260 			break;
261 		case 'T':
262 			if (strcmp(optarg, "list") == 0) {
263 				show_valid_options(IH_TYPE);
264 				exit(EXIT_SUCCESS);
265 			}
266 			type = genimg_get_type_id(optarg);
267 			if (type < 0) {
268 				show_valid_options(IH_TYPE);
269 				usage("Invalid image type");
270 			}
271 			break;
272 		case 'v':
273 			params.vflag++;
274 			break;
275 		case 'V':
276 			printf("mkimage version %s\n", PLAIN_VERSION);
277 			exit(EXIT_SUCCESS);
278 		case 'x':
279 			params.xflag++;
280 			break;
281 		default:
282 			usage("Invalid option");
283 		}
284 	}
285 
286 	/* The last parameter is expected to be the imagefile */
287 	if (optind < argc)
288 		params.imagefile = argv[optind];
289 
290 	/*
291 	 * For auto-generated FIT images we need to know the image type to put
292 	 * in the FIT, which is separate from the file's image type (which
293 	 * will always be IH_TYPE_FLATDT in this case).
294 	 */
295 	if (params.type == IH_TYPE_FLATDT) {
296 		params.fit_image_type = type ? type : IH_TYPE_KERNEL;
297 		/* For auto_its, datafile is always 'auto' */
298 		if (!params.auto_its)
299 			params.datafile = datafile;
300 		else if (!params.datafile)
301 			usage("Missing data file for auto-FIT (use -d)");
302 	} else if (type != IH_TYPE_INVALID) {
303 		if (type == IH_TYPE_SCRIPT && !params.datafile)
304 			usage("Missing data file for script (use -d)");
305 		params.type = type;
306 	}
307 
308 	if (!params.imagefile)
309 		usage("Missing output filename");
310 }
311 
312 int main(int argc, char **argv)
313 {
314 	int ifd = -1;
315 	struct stat sbuf;
316 	char *ptr;
317 	int retval = 0;
318 	struct image_type_params *tparams = NULL;
319 	int pad_len = 0;
320 	int dfd;
321 	size_t map_len;
322 
323 	params.cmdname = *argv;
324 	params.addr = 0;
325 	params.ep = 0;
326 
327 	process_args(argc, argv);
328 
329 	/* set tparams as per input type_id */
330 	tparams = imagetool_get_type(params.type);
331 	if (tparams == NULL) {
332 		fprintf (stderr, "%s: unsupported type %s\n",
333 			params.cmdname, genimg_get_type_name(params.type));
334 		exit (EXIT_FAILURE);
335 	}
336 
337 	/*
338 	 * check the passed arguments parameters meets the requirements
339 	 * as per image type to be generated/listed
340 	 */
341 	if (tparams->check_params)
342 		if (tparams->check_params (&params))
343 			usage("Bad parameters for image type");
344 
345 	if (!params.eflag) {
346 		params.ep = params.addr;
347 		/* If XIP, entry point must be after the U-Boot header */
348 		if (params.xflag)
349 			params.ep += tparams->header_size;
350 	}
351 
352 	if (params.fflag){
353 		if (tparams->fflag_handle)
354 			/*
355 			 * in some cases, some additional processing needs
356 			 * to be done if fflag is defined
357 			 *
358 			 * For ex. fit_handle_file for Fit file support
359 			 */
360 			retval = tparams->fflag_handle(&params);
361 
362 		if (retval != EXIT_SUCCESS)
363 			exit (retval);
364 	}
365 
366 	if (params.lflag || params.fflag) {
367 		ifd = open (params.imagefile, O_RDONLY|O_BINARY);
368 	} else {
369 		ifd = open (params.imagefile,
370 			O_RDWR|O_CREAT|O_TRUNC|O_BINARY, 0666);
371 	}
372 
373 	if (ifd < 0) {
374 		fprintf (stderr, "%s: Can't open %s: %s\n",
375 			params.cmdname, params.imagefile,
376 			strerror(errno));
377 		exit (EXIT_FAILURE);
378 	}
379 
380 	if (params.lflag || params.fflag) {
381 		/*
382 		 * list header information of existing image
383 		 */
384 		if (fstat(ifd, &sbuf) < 0) {
385 			fprintf (stderr, "%s: Can't stat %s: %s\n",
386 				params.cmdname, params.imagefile,
387 				strerror(errno));
388 			exit (EXIT_FAILURE);
389 		}
390 
391 		if ((unsigned)sbuf.st_size < tparams->header_size) {
392 			fprintf (stderr,
393 				"%s: Bad size: \"%s\" is not valid image\n",
394 				params.cmdname, params.imagefile);
395 			exit (EXIT_FAILURE);
396 		}
397 
398 		ptr = mmap(0, sbuf.st_size, PROT_READ, MAP_SHARED, ifd, 0);
399 		if (ptr == MAP_FAILED) {
400 			fprintf (stderr, "%s: Can't read %s: %s\n",
401 				params.cmdname, params.imagefile,
402 				strerror(errno));
403 			exit (EXIT_FAILURE);
404 		}
405 
406 		/*
407 		 * scan through mkimage registry for all supported image types
408 		 * and verify the input image file header for match
409 		 * Print the image information for matched image type
410 		 * Returns the error code if not matched
411 		 */
412 		retval = imagetool_verify_print_header(ptr, &sbuf,
413 				tparams, &params);
414 
415 		(void) munmap((void *)ptr, sbuf.st_size);
416 		(void) close (ifd);
417 
418 		exit (retval);
419 	}
420 
421 	if ((params.type != IH_TYPE_MULTI) && (params.type != IH_TYPE_SCRIPT)) {
422 		dfd = open(params.datafile, O_RDONLY | O_BINARY);
423 		if (dfd < 0) {
424 			fprintf(stderr, "%s: Can't open %s: %s\n",
425 				params.cmdname, params.datafile,
426 				strerror(errno));
427 			exit(EXIT_FAILURE);
428 		}
429 
430 		if (fstat(dfd, &sbuf) < 0) {
431 			fprintf(stderr, "%s: Can't stat %s: %s\n",
432 				params.cmdname, params.datafile,
433 				strerror(errno));
434 			exit(EXIT_FAILURE);
435 		}
436 
437 		params.file_size = sbuf.st_size + tparams->header_size;
438 		close(dfd);
439 	}
440 
441 	/*
442 	 * In case there an header with a variable
443 	 * length will be added, the corresponding
444 	 * function is called. This is responsible to
445 	 * allocate memory for the header itself.
446 	 */
447 	if (tparams->vrec_header)
448 		pad_len = tparams->vrec_header(&params, tparams);
449 	else
450 		memset(tparams->hdr, 0, tparams->header_size);
451 
452 	if (write(ifd, tparams->hdr, tparams->header_size)
453 					!= tparams->header_size) {
454 		fprintf (stderr, "%s: Write error on %s: %s\n",
455 			params.cmdname, params.imagefile, strerror(errno));
456 		exit (EXIT_FAILURE);
457 	}
458 
459 	if (!params.skipcpy) {
460 		if (params.type == IH_TYPE_MULTI ||
461 		    params.type == IH_TYPE_SCRIPT) {
462 			char *file = params.datafile;
463 			uint32_t size;
464 
465 			for (;;) {
466 				char *sep = NULL;
467 
468 				if (file) {
469 					if ((sep = strchr(file, ':')) != NULL) {
470 						*sep = '\0';
471 					}
472 
473 					if (stat (file, &sbuf) < 0) {
474 						fprintf (stderr, "%s: Can't stat %s: %s\n",
475 							 params.cmdname, file, strerror(errno));
476 						exit (EXIT_FAILURE);
477 					}
478 					size = cpu_to_uimage (sbuf.st_size);
479 				} else {
480 					size = 0;
481 				}
482 
483 				if (write(ifd, (char *)&size, sizeof(size)) != sizeof(size)) {
484 					fprintf (stderr, "%s: Write error on %s: %s\n",
485 						 params.cmdname, params.imagefile,
486 						 strerror(errno));
487 					exit (EXIT_FAILURE);
488 				}
489 
490 				if (!file) {
491 					break;
492 				}
493 
494 				if (sep) {
495 					*sep = ':';
496 					file = sep + 1;
497 				} else {
498 					file = NULL;
499 				}
500 			}
501 
502 			file = params.datafile;
503 
504 			for (;;) {
505 				char *sep = strchr(file, ':');
506 				if (sep) {
507 					*sep = '\0';
508 					copy_file (ifd, file, 1);
509 					*sep++ = ':';
510 					file = sep;
511 				} else {
512 					copy_file (ifd, file, 0);
513 					break;
514 				}
515 			}
516 		} else if (params.type == IH_TYPE_PBLIMAGE) {
517 			/* PBL has special Image format, implements its' own */
518 			pbl_load_uboot(ifd, &params);
519 		} else if (params.type == IH_TYPE_ZYNQMPBIF) {
520 			/* Image file is meta, walk through actual targets */
521 			int ret;
522 
523 			ret = zynqmpbif_copy_image(ifd, &params);
524 			if (ret)
525 				return ret;
526 		} else if (params.type == IH_TYPE_IMX8IMAGE) {
527 			/* i.MX8/8X has special Image format */
528 			int ret;
529 
530 			ret = imx8image_copy_image(ifd, &params);
531 			if (ret)
532 				return ret;
533 		} else if (params.type == IH_TYPE_IMX8MIMAGE) {
534 			/* i.MX8M has special Image format */
535 			int ret;
536 
537 			ret = imx8mimage_copy_image(ifd, &params);
538 			if (ret)
539 				return ret;
540 		} else {
541 			copy_file(ifd, params.datafile, pad_len);
542 		}
543 		if (params.type == IH_TYPE_FIRMWARE_IVT) {
544 			/* Add alignment and IVT */
545 			uint32_t aligned_filesize = (params.file_size + 0x1000
546 					- 1) & ~(0x1000 - 1);
547 			flash_header_v2_t ivt_header = { { 0xd1, 0x2000, 0x40 },
548 					params.addr, 0, 0, 0, params.addr
549 							+ aligned_filesize
550 							- tparams->header_size,
551 					params.addr + aligned_filesize
552 							- tparams->header_size
553 							+ 0x20, 0 };
554 			int i = params.file_size;
555 			for (; i < aligned_filesize; i++) {
556 				if (write(ifd, (char *) &i, 1) != 1) {
557 					fprintf(stderr,
558 							"%s: Write error on %s: %s\n",
559 							params.cmdname,
560 							params.imagefile,
561 							strerror(errno));
562 					exit(EXIT_FAILURE);
563 				}
564 			}
565 			if (write(ifd, &ivt_header, sizeof(flash_header_v2_t))
566 					!= sizeof(flash_header_v2_t)) {
567 				fprintf(stderr, "%s: Write error on %s: %s\n",
568 						params.cmdname,
569 						params.imagefile,
570 						strerror(errno));
571 				exit(EXIT_FAILURE);
572 			}
573 		}
574 	}
575 
576 	/* We're a bit of paranoid */
577 #if defined(_POSIX_SYNCHRONIZED_IO) && \
578    !defined(__sun__) && \
579    !defined(__FreeBSD__) && \
580    !defined(__OpenBSD__) && \
581    !defined(__APPLE__)
582 	(void) fdatasync (ifd);
583 #else
584 	(void) fsync (ifd);
585 #endif
586 
587 	if (fstat(ifd, &sbuf) < 0) {
588 		fprintf (stderr, "%s: Can't stat %s: %s\n",
589 			params.cmdname, params.imagefile, strerror(errno));
590 		exit (EXIT_FAILURE);
591 	}
592 	params.file_size = sbuf.st_size;
593 
594 	map_len = sbuf.st_size;
595 	ptr = mmap(0, map_len, PROT_READ | PROT_WRITE, MAP_SHARED, ifd, 0);
596 	if (ptr == MAP_FAILED) {
597 		fprintf (stderr, "%s: Can't map %s: %s\n",
598 			params.cmdname, params.imagefile, strerror(errno));
599 		exit (EXIT_FAILURE);
600 	}
601 
602 	/* Setup the image header as per input image type*/
603 	if (tparams->set_header)
604 		tparams->set_header (ptr, &sbuf, ifd, &params);
605 	else {
606 		fprintf (stderr, "%s: Can't set header for %s: %s\n",
607 			params.cmdname, tparams->name, strerror(errno));
608 		exit (EXIT_FAILURE);
609 	}
610 
611 	/* Print the image information by processing image header */
612 	if (tparams->print_header)
613 		tparams->print_header (ptr);
614 	else {
615 		fprintf (stderr, "%s: Can't print header for %s\n",
616 			params.cmdname, tparams->name);
617 	}
618 
619 	(void)munmap((void *)ptr, map_len);
620 
621 	/* We're a bit of paranoid */
622 #if defined(_POSIX_SYNCHRONIZED_IO) && \
623    !defined(__sun__) && \
624    !defined(__FreeBSD__) && \
625    !defined(__OpenBSD__) && \
626    !defined(__APPLE__)
627 	(void) fdatasync (ifd);
628 #else
629 	(void) fsync (ifd);
630 #endif
631 
632 	if (close(ifd)) {
633 		fprintf (stderr, "%s: Write error on %s: %s\n",
634 			params.cmdname, params.imagefile, strerror(errno));
635 		exit (EXIT_FAILURE);
636 	}
637 
638 	exit (EXIT_SUCCESS);
639 }
640 
641 static void
642 copy_file (int ifd, const char *datafile, int pad)
643 {
644 	int dfd;
645 	struct stat sbuf;
646 	unsigned char *ptr;
647 	int tail;
648 	int zero = 0;
649 	uint8_t zeros[4096];
650 	int offset = 0;
651 	int size;
652 	struct image_type_params *tparams = imagetool_get_type(params.type);
653 
654 	memset(zeros, 0, sizeof(zeros));
655 
656 	if (params.vflag) {
657 		fprintf (stderr, "Adding Image %s\n", datafile);
658 	}
659 
660 	if ((dfd = open(datafile, O_RDONLY|O_BINARY)) < 0) {
661 		fprintf (stderr, "%s: Can't open %s: %s\n",
662 			params.cmdname, datafile, strerror(errno));
663 		exit (EXIT_FAILURE);
664 	}
665 
666 	if (fstat(dfd, &sbuf) < 0) {
667 		fprintf (stderr, "%s: Can't stat %s: %s\n",
668 			params.cmdname, datafile, strerror(errno));
669 		exit (EXIT_FAILURE);
670 	}
671 
672 	ptr = mmap(0, sbuf.st_size, PROT_READ, MAP_SHARED, dfd, 0);
673 	if (ptr == MAP_FAILED) {
674 		fprintf (stderr, "%s: Can't read %s: %s\n",
675 			params.cmdname, datafile, strerror(errno));
676 		exit (EXIT_FAILURE);
677 	}
678 
679 	if (params.xflag) {
680 		unsigned char *p = NULL;
681 		/*
682 		 * XIP: do not append the image_header_t at the
683 		 * beginning of the file, but consume the space
684 		 * reserved for it.
685 		 */
686 
687 		if ((unsigned)sbuf.st_size < tparams->header_size) {
688 			fprintf (stderr,
689 				"%s: Bad size: \"%s\" is too small for XIP\n",
690 				params.cmdname, datafile);
691 			exit (EXIT_FAILURE);
692 		}
693 
694 		for (p = ptr; p < ptr + tparams->header_size; p++) {
695 			if ( *p != 0xff ) {
696 				fprintf (stderr,
697 					"%s: Bad file: \"%s\" has invalid buffer for XIP\n",
698 					params.cmdname, datafile);
699 				exit (EXIT_FAILURE);
700 			}
701 		}
702 
703 		offset = tparams->header_size;
704 	}
705 
706 	size = sbuf.st_size - offset;
707 	if (write(ifd, ptr + offset, size) != size) {
708 		fprintf (stderr, "%s: Write error on %s: %s\n",
709 			params.cmdname, params.imagefile, strerror(errno));
710 		exit (EXIT_FAILURE);
711 	}
712 
713 	tail = size % 4;
714 	if ((pad == 1) && (tail != 0)) {
715 
716 		if (write(ifd, (char *)&zero, 4-tail) != 4-tail) {
717 			fprintf (stderr, "%s: Write error on %s: %s\n",
718 				params.cmdname, params.imagefile,
719 				strerror(errno));
720 			exit (EXIT_FAILURE);
721 		}
722 	} else if (pad > 1) {
723 		while (pad > 0) {
724 			int todo = sizeof(zeros);
725 
726 			if (todo > pad)
727 				todo = pad;
728 			if (write(ifd, (char *)&zeros, todo) != todo) {
729 				fprintf(stderr, "%s: Write error on %s: %s\n",
730 					params.cmdname, params.imagefile,
731 					strerror(errno));
732 				exit(EXIT_FAILURE);
733 			}
734 			pad -= todo;
735 		}
736 	}
737 
738 	(void) munmap((void *)ptr, sbuf.st_size);
739 	(void) close (dfd);
740 }
741