xref: /netbsd-src/usr.bin/elf2aout/elf2aout.c (revision 112e865a87c01cd00a91bd7a03b7e817f2ea533f)
1 /*	$NetBSD: elf2aout.c,v 1.25 2024/11/01 00:35:53 gutteridge Exp $	*/
2 
3 /*
4  * Copyright (c) 1995
5  *	Ted Lemon (hereinafter referred to as the author)
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 /* elf2aout.c
32 
33    This program converts an elf executable to a NetBSD a.out executable.
34    The minimal symbol table is copied, but the debugging symbols and
35    other informational sections are not. */
36 
37 #if HAVE_NBTOOL_CONFIG_H
38 #include "nbtool_config.h"
39 #endif
40 
41 #ifndef TARGET_BYTE_ORDER
42 #define TARGET_BYTE_ORDER	BYTE_ORDER
43 #endif
44 
45 #include <sys/types.h>
46 #include <sys/endian.h>
47 #include <sys/exec_aout.h>
48 #include <sys/exec_elf.h>
49 
50 #include <a.out.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <limits.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 
60 
61 struct sect {
62 	/* should be unsigned long, but assume no a.out binaries on LP64 */
63 	uint32_t vaddr;
64 	uint32_t len;
65 };
66 
67 static void	combine(struct sect *, struct sect *, int);
68 static int	phcmp(const void *, const void *);
69 static void   *saveRead(int file, off_t offset, size_t len, const char *name);
70 static void	copy(int, int, off_t, off_t);
71 static void	translate_syms(int, int, off_t, off_t, off_t, off_t);
72 
73 #if TARGET_BYTE_ORDER != BYTE_ORDER
74 static void	bswap32_region(int32_t* , int);
75 #endif
76 
77 static int    *symTypeTable;
78 static int     debug;
79 
80 static __dead void
81 usage(void)
82 {
83 	fprintf(stderr, "Usage: %s [-Os] <elf executable> <a.out executable>\n",
84 	    getprogname());
85 	exit(EXIT_FAILURE);
86 }
87 
88 static const struct {
89 	const char *n;
90 	int v;
91 } nv[] = {
92 	{ ".text", N_TEXT },
93 	{ ".rodata", N_TEXT },
94 	{ ".data", N_DATA },
95 	{ ".sdata", N_DATA },
96 	{ ".lit4", N_DATA },
97 	{ ".lit8", N_DATA },
98 	{ ".bss", N_BSS },
99 	{ ".sbss", N_BSS },
100 };
101 
102 static int
103 get_symtab_type(const char *name)
104 {
105 	size_t i;
106 	for (i = 0; i < __arraycount(nv); i++) {
107 		if (strcmp(name, nv[i].n) == 0)
108 			return nv[i].v;
109 	}
110 	if (debug)
111 		warnx("section `%s' is not handled\n", name);
112 	return 0;
113 }
114 
115 static uint32_t
116 get_mid(const Elf32_Ehdr *ex)
117 {
118 	switch (ex->e_machine) {
119 #ifdef notyet
120 	case EM_AARCH64:
121 		return MID_AARCH64;
122 	case EM_ALPHA:
123 		return MID_ALPHA;
124 #endif
125 	case EM_ARM:
126 		return MID_ARM6;
127 #ifdef notyet
128 	case EM_PARISC:
129 		return MID_HPPA;
130 #endif
131 	case EM_386:
132 		return MID_I386;
133 	case EM_68K:
134 		return MID_M68K;
135 	case EM_OR1K:
136 		return MID_OR1K;
137 	case EM_MIPS:
138 		if (ex->e_ident[EI_DATA] == ELFDATA2LSB)
139 			return MID_PMAX;
140 		else
141 			return MID_MIPS;
142 	case EM_PPC:
143 		return MID_POWERPC;
144 #ifdef notyet
145 	case EM_PPC64:
146 		return MID_POWERPC64;
147 		break;
148 #endif
149 	case EM_RISCV:
150 		return MID_RISCV;
151 	case EM_SH:
152 		return MID_SH3;
153 	case EM_SPARC:
154 	case EM_SPARC32PLUS:
155 	case EM_SPARCV9:
156 		if (ex->e_ident[EI_CLASS] == ELFCLASS32)
157 			return MID_SPARC;
158 #ifdef notyet
159 		return MID_SPARC64;
160 	case EM_X86_64:
161 		return MID_X86_64;
162 #else
163 		break;
164 #endif
165 	case EM_VAX:
166 		return MID_VAX;
167 	case EM_NONE:
168 		return MID_ZERO;
169 	default:
170 		break;
171 	}
172 	if (debug)
173 		warnx("Unsupported machine `%d'", ex->e_machine);
174 	return MID_ZERO;
175 }
176 
177 static unsigned char
178 get_type(Elf32_Half shndx)
179 {
180 	switch (shndx) {
181 	case SHN_UNDEF:
182 		return N_UNDF;
183 	case SHN_ABS:
184 		return N_ABS;
185 	case SHN_COMMON:
186 	case SHN_MIPS_ACOMMON:
187 		return N_COMM;
188 	default:
189 		return (unsigned char)symTypeTable[shndx];
190 	}
191 }
192 
193 int
194 main(int argc, char **argv)
195 {
196 	Elf32_Ehdr ex;
197 	Elf32_Phdr *ph;
198 	Elf32_Shdr *sh;
199 	char   *shstrtab;
200 	ssize_t i, strtabix, symtabix;
201 	struct sect text, data, bss;
202 	struct exec aex;
203 	int     infile, outfile;
204 	uint32_t cur_vma = UINT32_MAX;
205 	uint32_t mid;
206 	int symflag = 0, c;
207 	unsigned long magic = ZMAGIC;
208 
209 	strtabix = symtabix = 0;
210 	text.len = data.len = bss.len = 0;
211 	text.vaddr = data.vaddr = bss.vaddr = 0;
212 
213 	while ((c = getopt(argc, argv, "dOs")) != -1) {
214 		switch (c) {
215 		case 'd':
216 			debug++;
217 			break;
218 		case 's':
219 			symflag = 1;
220 			break;
221 		case 'O':
222 			magic = OMAGIC;
223 			break;
224 		case '?':
225 		default:
226 		usage:
227 			usage();
228 		}
229 	}
230 
231 	argc -= optind;
232 	argv += optind;
233 
234 	/* Check args... */
235 	if (argc != 2)
236 		goto usage;
237 
238 
239 	/* Try the input file... */
240 	if ((infile = open(argv[0], O_RDONLY)) < 0)
241 		err(EXIT_FAILURE, "Can't open `%s' for read", argv[0]);
242 
243 	/* Read the header, which is at the beginning of the file... */
244 	i = read(infile, &ex, sizeof ex);
245 	if (i != sizeof ex) {
246 		if (i == -1)
247 			err(EXIT_FAILURE, "Error reading `%s'", argv[1]);
248 		else
249 			errx(EXIT_FAILURE, "End of file reading `%s'", argv[1]);
250 	}
251 #if TARGET_BYTE_ORDER != BYTE_ORDER
252 	ex.e_type	= bswap16(ex.e_type);
253 	ex.e_machine	= bswap16(ex.e_machine);
254 	ex.e_version	= bswap32(ex.e_version);
255 	ex.e_entry 	= bswap32(ex.e_entry);
256 	ex.e_phoff	= bswap32(ex.e_phoff);
257 	ex.e_shoff	= bswap32(ex.e_shoff);
258 	ex.e_flags	= bswap32(ex.e_flags);
259 	ex.e_ehsize	= bswap16(ex.e_ehsize);
260 	ex.e_phentsize	= bswap16(ex.e_phentsize);
261 	ex.e_phnum	= bswap16(ex.e_phnum);
262 	ex.e_shentsize	= bswap16(ex.e_shentsize);
263 	ex.e_shnum	= bswap16(ex.e_shnum);
264 	ex.e_shstrndx	= bswap16(ex.e_shstrndx);
265 #endif
266 	// Not yet
267 	if (ex.e_ident[EI_CLASS] == ELFCLASS64)
268 		errx(EXIT_FAILURE, "Only 32 bit is supported");
269 
270 	/* Read the program headers... */
271 	ph = saveRead(infile, ex.e_phoff,
272 	    (size_t)ex.e_phnum * sizeof(Elf32_Phdr), "ph");
273 #if TARGET_BYTE_ORDER != BYTE_ORDER
274 	bswap32_region((int32_t*)ph, sizeof(Elf32_Phdr) * ex.e_phnum);
275 #endif
276 	/* Read the section headers... */
277 	sh = saveRead(infile, ex.e_shoff,
278 	    (size_t)ex.e_shnum * sizeof(Elf32_Shdr), "sh");
279 #if TARGET_BYTE_ORDER != BYTE_ORDER
280 	bswap32_region((int32_t*)sh, sizeof(Elf32_Shdr) * ex.e_shnum);
281 #endif
282 	/* Read in the section string table. */
283 	shstrtab = saveRead(infile, sh[ex.e_shstrndx].sh_offset,
284 	    (size_t)sh[ex.e_shstrndx].sh_size, "shstrtab");
285 
286 	/* Find space for a table matching ELF section indices to a.out symbol
287 	 * types. */
288 	symTypeTable = malloc(ex.e_shnum * sizeof(int));
289 	if (symTypeTable == NULL)
290 		err(EXIT_FAILURE, "symTypeTable: can't allocate");
291 	memset(symTypeTable, 0, ex.e_shnum * sizeof(int));
292 
293 	/* Look for the symbol table and string table... Also map section
294 	 * indices to symbol types for a.out */
295 	for (i = 0; i < ex.e_shnum; i++) {
296 		char   *name = shstrtab + sh[i].sh_name;
297 		if (!strcmp(name, ".symtab"))
298 			symtabix = i;
299 		else if (!strcmp(name, ".strtab"))
300 			strtabix = i;
301 		else
302 			symTypeTable[i] = get_symtab_type(name);
303 	}
304 
305 	/* Figure out if we can cram the program header into an a.out
306 	 * header... Basically, we can't handle anything but loadable
307 	 * segments, but we can ignore some kinds of segments.   We can't
308 	 * handle holes in the address space, and we handle start addresses
309 	 * other than 0x1000 by hoping that the loader will know where to load
310 	 * - a.out doesn't have an explicit load address.   Segments may be
311 	 * out of order, so we sort them first. */
312 	qsort(ph, ex.e_phnum, sizeof(Elf32_Phdr), phcmp);
313 	for (i = 0; i < ex.e_phnum; i++) {
314 		/* Section types we can ignore... */
315 		if (ph[i].p_type == PT_NULL || ph[i].p_type == PT_NOTE ||
316 		    ph[i].p_type == PT_PHDR || ph[i].p_type == PT_MIPS_REGINFO)
317 			continue;
318 		/* Section types we can't handle... */
319 		if (ph[i].p_type == PT_TLS) {
320 			if (debug)
321 				warnx("Can't handle TLS section");
322 			continue;
323 		}
324 		if (ph[i].p_type != PT_LOAD)
325 			errx(EXIT_FAILURE, "Program header %zd "
326 			    "type %d can't be converted.", i, ph[i].p_type);
327 		/* Writable (data) segment? */
328 		if (ph[i].p_flags & PF_W) {
329 			struct sect ndata, nbss;
330 
331 			ndata.vaddr = ph[i].p_vaddr;
332 			ndata.len = ph[i].p_filesz;
333 			nbss.vaddr = ph[i].p_vaddr + ph[i].p_filesz;
334 			nbss.len = ph[i].p_memsz - ph[i].p_filesz;
335 
336 			combine(&data, &ndata, 0);
337 			combine(&bss, &nbss, 1);
338 		} else {
339 			struct sect ntxt;
340 
341 			ntxt.vaddr = ph[i].p_vaddr;
342 			ntxt.len = ph[i].p_filesz;
343 
344 			combine(&text, &ntxt, 0);
345 		}
346 		/* Remember the lowest segment start address. */
347 		if (ph[i].p_vaddr < cur_vma)
348 			cur_vma = ph[i].p_vaddr;
349 	}
350 
351 	/* Sections must be in order to be converted... */
352 	if (text.vaddr > data.vaddr || data.vaddr > bss.vaddr ||
353 	    text.vaddr + text.len > data.vaddr ||
354 	    data.vaddr + data.len > bss.vaddr)
355 		errx(EXIT_FAILURE, "Sections ordering prevents a.out "
356 		    "conversion.");
357 	/* If there's a data section but no text section, then the loader
358 	 * combined everything into one section.   That needs to be the text
359 	 * section, so just make the data section zero length following text. */
360 	if (data.len && text.len == 0) {
361 		text = data;
362 		data.vaddr = text.vaddr + text.len;
363 		data.len = 0;
364 	}
365 	/* If there is a gap between text and data, we'll fill it when we copy
366 	 * the data, so update the length of the text segment as represented
367 	 * in a.out to reflect that, since a.out doesn't allow gaps in the
368 	 * program address space. */
369 	if (text.vaddr + text.len < data.vaddr)
370 		text.len = data.vaddr - text.vaddr;
371 
372 	/* We now have enough information to cons up an a.out header... */
373 	mid = get_mid(&ex);
374 	aex.a_midmag = (u_long)htobe32(((u_long)symflag << 26)
375 	    | ((u_long)mid << 16) | magic);
376 
377 	aex.a_text = text.len;
378 	aex.a_data = data.len;
379 	aex.a_bss = bss.len;
380 	aex.a_entry = ex.e_entry;
381 	aex.a_syms = (sizeof(struct nlist) *
382 	    (symtabix != -1 ? sh[symtabix].sh_size / sizeof(Elf32_Sym) : 0));
383 	aex.a_trsize = 0;
384 	aex.a_drsize = 0;
385 #if TARGET_BYTE_ORDER != BYTE_ORDER
386 	aex.a_text = bswap32(aex.a_text);
387 	aex.a_data = bswap32(aex.a_data);
388 	aex.a_bss = bswap32(aex.a_bss);
389 	aex.a_entry = bswap32(aex.a_entry);
390 	aex.a_syms = bswap32(aex.a_syms);
391 	aex.a_trsize = bswap32(aex.a_trsize);
392 	aex.a_drsize = bswap32(aex.a_drsize);
393 #endif
394 
395 	/* Make the output file... */
396 	if ((outfile = open(argv[1], O_WRONLY | O_CREAT, 0777)) < 0)
397 		err(EXIT_FAILURE, "Unable to create `%s'", argv[1]);
398 	/* Truncate file... */
399 	if (ftruncate(outfile, 0)) {
400 		warn("ftruncate %s", argv[1]);
401 	}
402 	/* Write the header... */
403 	i = write(outfile, &aex, sizeof aex);
404 	if (i != sizeof aex)
405 		err(EXIT_FAILURE, "Can't write `%s'", argv[1]);
406 	/* Copy the loadable sections.   Zero-fill any gaps less than 64k;
407 	 * complain about any zero-filling, and die if we're asked to
408 	 * zero-fill more than 64k. */
409 	for (i = 0; i < ex.e_phnum; i++) {
410 		/* Unprocessable sections were handled above, so just verify
411 		 * that the section can be loaded before copying. */
412 		if (ph[i].p_type == PT_LOAD && ph[i].p_filesz) {
413 			if (cur_vma != ph[i].p_vaddr) {
414 				uint32_t gap = ph[i].p_vaddr - cur_vma;
415 				char    obuf[1024];
416 				if (gap > 65536)
417 					errx(EXIT_FAILURE,
418 			"Intersegment gap (%u bytes) too large", gap);
419 				if (debug)
420 					warnx("%u byte intersegment gap", gap);
421 				memset(obuf, 0, sizeof obuf);
422 				while (gap) {
423 					ssize_t count = write(outfile, obuf,
424 					    (gap > sizeof obuf
425 					    ? sizeof obuf : gap));
426 					if (count < 0)
427 						err(EXIT_FAILURE,
428 						    "Error writing gap");
429 					gap -= (uint32_t)count;
430 				}
431 			}
432 			copy(outfile, infile, ph[i].p_offset, ph[i].p_filesz);
433 			cur_vma = ph[i].p_vaddr + ph[i].p_filesz;
434 		}
435 	}
436 
437 	/* Copy and translate the symbol table... */
438 	translate_syms(outfile, infile,
439 	    sh[symtabix].sh_offset, sh[symtabix].sh_size,
440 	    sh[strtabix].sh_offset, sh[strtabix].sh_size);
441 
442 	free(ph);
443 	free(sh);
444 	free(shstrtab);
445 	free(symTypeTable);
446 	/* Looks like we won... */
447 	return EXIT_SUCCESS;
448 }
449 /* translate_syms (out, in, offset, size)
450 
451    Read the ELF symbol table from in at offset; translate it into a.out
452    nlist format and write it to out. */
453 
454 void
455 translate_syms(int out, int in, off_t symoff, off_t symsize,
456     off_t stroff, off_t strsize)
457 {
458 #define SYMS_PER_PASS	64
459 	Elf32_Sym inbuf[64];
460 	struct nlist outbuf[64];
461 	ssize_t i, remaining, cur;
462 	char   *oldstrings;
463 	char   *newstrings, *nsp;
464 	size_t  newstringsize;
465 	uint32_t stringsizebuf;
466 
467 	/* Zero the unused fields in the output buffer.. */
468 	memset(outbuf, 0, sizeof outbuf);
469 
470 	/* Find number of symbols to process... */
471 	remaining = (ssize_t)(symsize / (off_t)sizeof(Elf32_Sym));
472 
473 	/* Suck in the old string table... */
474 	oldstrings = saveRead(in, stroff, (size_t)strsize, "string table");
475 
476 	/*
477 	 * Allocate space for the new one.  We will increase the space if
478 	 * this is too small
479 	 */
480 	newstringsize = (size_t)(strsize + remaining);
481 	newstrings = malloc(newstringsize);
482 	if (newstrings == NULL)
483 		err(EXIT_FAILURE, "No memory for new string table!");
484 	/* Initialize the table pointer... */
485 	nsp = newstrings;
486 
487 	/* Go the start of the ELF symbol table... */
488 	if (lseek(in, symoff, SEEK_SET) < 0)
489 		err(EXIT_FAILURE, "Can't seek");
490 	/* Translate and copy symbols... */
491 	for (; remaining; remaining -= cur) {
492 		cur = remaining;
493 		if (cur > SYMS_PER_PASS)
494 			cur = SYMS_PER_PASS;
495 		if ((i = read(in, inbuf, (size_t)cur * sizeof(Elf32_Sym)))
496 		    != cur * (ssize_t)sizeof(Elf32_Sym)) {
497 			if (i < 0)
498 				err(EXIT_FAILURE, "%s: read error", __func__);
499 			else
500 				errx(EXIT_FAILURE, "%s: premature end of file",
501 					__func__);
502 		}
503 		/* Do the translation... */
504 		for (i = 0; i < cur; i++) {
505 			int     binding, type;
506 			size_t off, len;
507 
508 #if TARGET_BYTE_ORDER != BYTE_ORDER
509 			inbuf[i].st_name  = bswap32(inbuf[i].st_name);
510 			inbuf[i].st_value = bswap32(inbuf[i].st_value);
511 			inbuf[i].st_size  = bswap32(inbuf[i].st_size);
512 			inbuf[i].st_shndx = bswap16(inbuf[i].st_shndx);
513 #endif
514 			off = (size_t)(nsp - newstrings);
515 
516 			/* length of this symbol with leading '_' and trailing '\0' */
517 			len = strlen(oldstrings + inbuf[i].st_name) + 1 + 1;
518 
519 			/* Does it fit? If not make more space */
520 			if (newstringsize - off < len) {
521 				char *nns;
522 
523 				newstringsize += (size_t)(remaining) * len;
524 				nns = realloc(newstrings, newstringsize);
525 				if (nns == NULL)
526 					err(EXIT_FAILURE, "No memory for new string table!");
527 				newstrings = nns;
528 				nsp = newstrings + off;
529 			}
530 			/* Copy the symbol into the new table, but prepend an
531 			 * underscore. */
532 			*nsp = '_';
533 			strcpy(nsp + 1, oldstrings + inbuf[i].st_name);
534 			outbuf[i].n_un.n_strx = nsp - newstrings + 4;
535 			nsp += len;
536 
537 			type = ELF32_ST_TYPE(inbuf[i].st_info);
538 			binding = ELF32_ST_BIND(inbuf[i].st_info);
539 
540 			/* Convert ELF symbol type/section/etc info into a.out
541 			 * type info. */
542 			if (type == STT_FILE)
543 				outbuf[i].n_type = N_FN;
544 			else
545 				outbuf[i].n_type = get_type(inbuf[i].st_shndx);
546 			if (binding == STB_GLOBAL)
547 				outbuf[i].n_type |= N_EXT;
548 			/* Symbol values in executables should be compatible. */
549 			outbuf[i].n_value = inbuf[i].st_value;
550 #if TARGET_BYTE_ORDER != BYTE_ORDER
551 			outbuf[i].n_un.n_strx = bswap32(outbuf[i].n_un.n_strx);
552 			outbuf[i].n_desc      = bswap16(outbuf[i].n_desc);
553 			outbuf[i].n_value     = bswap32(outbuf[i].n_value);
554 #endif
555 		}
556 		/* Write out the symbols... */
557 		if ((i = write(out, outbuf, (size_t)cur * sizeof(struct nlist)))
558 		    != cur * (ssize_t)sizeof(struct nlist))
559 			err(EXIT_FAILURE, "%s: write failed", __func__);
560 	}
561 	/* Write out the string table length... */
562 	stringsizebuf = (uint32_t)newstringsize;
563 #if TARGET_BYTE_ORDER != BYTE_ORDER
564 	stringsizebuf = bswap32(stringsizebuf);
565 #endif
566 	if (write(out, &stringsizebuf, sizeof stringsizebuf)
567 	    != sizeof stringsizebuf)
568 		err(EXIT_FAILURE, "%s: newstringsize: write failed", __func__);
569 	/* Write out the string table... */
570 	if (write(out, newstrings, newstringsize) != (ssize_t)newstringsize)
571 		err(EXIT_FAILURE, "%s: newstrings: write failed", __func__);
572 	free(newstrings);
573 	free(oldstrings);
574 }
575 
576 static void
577 copy(int out, int in, off_t offset, off_t size)
578 {
579 	char    ibuf[4096];
580 	ssize_t remaining, cur, count;
581 
582 	/* Go to the start of the segment... */
583 	if (lseek(in, offset, SEEK_SET) < 0)
584 		err(EXIT_FAILURE, "%s: lseek failed", __func__);
585 	if (size > SSIZE_MAX)
586 		err(EXIT_FAILURE, "%s: can not copy this much", __func__);
587 	remaining = (ssize_t)size;
588 	while (remaining) {
589 		cur = remaining;
590 		if (cur > (int)sizeof ibuf)
591 			cur = sizeof ibuf;
592 		remaining -= cur;
593 		if ((count = read(in, ibuf, (size_t)cur)) != cur) {
594 			if (count < 0)
595 				err(EXIT_FAILURE, "%s: read error", __func__);
596 			else
597 				errx(EXIT_FAILURE, "%s: premature end of file",
598 					__func__);
599 		}
600 		if ((count = write(out, ibuf, (size_t)cur)) != cur)
601 			err(EXIT_FAILURE, "%s: write failed", __func__);
602 	}
603 }
604 
605 /* Combine two segments, which must be contiguous.   If pad is true, it's
606    okay for there to be padding between. */
607 static void
608 combine(struct sect *base, struct sect *new, int pad)
609 {
610 
611 	if (base->len == 0)
612 		*base = *new;
613 	else
614 		if (new->len) {
615 			if (base->vaddr + base->len != new->vaddr) {
616 				if (pad)
617 					base->len = new->vaddr - base->vaddr;
618 				else
619 					errx(EXIT_FAILURE, "Non-contiguous "
620 					    "data can't be converted");
621 			}
622 			base->len += new->len;
623 		}
624 }
625 
626 static int
627 phcmp(const void *vh1, const void *vh2)
628 {
629 	const Elf32_Phdr *h1, *h2;
630 
631 	h1 = (const Elf32_Phdr *)vh1;
632 	h2 = (const Elf32_Phdr *)vh2;
633 
634 	if (h1->p_vaddr > h2->p_vaddr)
635 		return 1;
636 	else
637 		if (h1->p_vaddr < h2->p_vaddr)
638 			return -1;
639 		else
640 			return 0;
641 }
642 
643 static void *
644 saveRead(int file, off_t offset, size_t len, const char *name)
645 {
646 	char   *tmp;
647 	ssize_t count;
648 	off_t   off;
649 
650 	if ((off = lseek(file, offset, SEEK_SET)) < 0)
651 		errx(EXIT_FAILURE, "%s: seek failed", name);
652 	if ((tmp = malloc(len)) == NULL)
653 		errx(EXIT_FAILURE,
654 		    "%s: Can't allocate %jd bytes.", name, (intmax_t)len);
655 	count = read(file, tmp, len);
656 	if ((size_t)count != len) {
657 		if (count < 0)
658 			err(EXIT_FAILURE, "%s: read error", name);
659 		else
660 			errx(EXIT_FAILURE, "%s: premature end of file",
661 			    name);
662 	}
663 	return tmp;
664 }
665 
666 #if TARGET_BYTE_ORDER != BYTE_ORDER
667 /* swap a 32bit region */
668 static void
669 bswap32_region(int32_t* p, int len)
670 {
671 	size_t i;
672 
673 	for (i = 0; i < len / sizeof(int32_t); i++, p++)
674 		*p = bswap32(*p);
675 }
676 #endif
677