xref: /netbsd-src/usr.bin/elf2ecoff/elf2ecoff.c (revision a5847cc334d9a7029f6352b847e9e8d71a0f9e0c)
1 /*	$NetBSD: elf2ecoff.c,v 1.28 2011/08/23 20:27:22 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997 Jonathan Stone
5  *    All rights reserved.
6  * Copyright (c) 1995
7  *	Ted Lemon (hereinafter referred to as the author)
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. The name of the author may not be used to endorse or promote products
18  *    derived from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 /* elf2ecoff.c
34 
35    This program converts an elf executable to an ECOFF executable.
36    No symbol table is retained.   This is useful primarily in building
37    net-bootable kernels for machines (e.g., DECstation and Alpha) which
38    only support the ECOFF object file format. */
39 
40 #if HAVE_NBTOOL_CONFIG_H
41 #include "nbtool_config.h"
42 #endif
43 
44 #include <sys/types.h>
45 #include <err.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <unistd.h>
49 #include <sys/exec_elf.h>
50 #include <stdio.h>
51 #include <sys/exec_ecoff.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <limits.h>
55 
56 #define	ISLAST(p)	(p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
57 
58 struct sect {
59 	unsigned long vaddr;
60 	unsigned long len;
61 };
62 
63 struct elf_syms {
64 	int     nsymbols;
65 	Elf32_Sym *elf_syms;
66 	off_t   stringsize;
67 	char   *stringtab;
68 };
69 
70 struct ecoff_syms {
71 	int     nsymbols;
72 	struct ecoff_extsym *ecoff_syms;
73 	off_t   stringsize;
74 	char   *stringtab;
75 };
76 
77 static int     debug = 0;
78 static int     needswap;
79 
80 static int     phcmp(Elf32_Phdr *, Elf32_Phdr *);
81 static char   *saveRead(int, off_t, off_t, const char *);
82 static void    safewrite(int, const void *, off_t, const char *);
83 static void    copy(int, int, off_t, off_t);
84 static void    combine(struct sect *, struct sect *, int);
85 static void    translate_syms(struct elf_syms *, struct ecoff_syms *);
86 static void    elf_symbol_table_to_ecoff(int, int, struct ecoff_exechdr *,
87     off_t, off_t, off_t, off_t);
88 static int     make_ecoff_section_hdrs(struct ecoff_exechdr *,
89     struct ecoff_scnhdr *);
90 static void    write_ecoff_symhdr(int, struct ecoff_exechdr *,
91     struct ecoff_symhdr *, long, long, long, long);
92 static void    pad16(int, int, const char *);
93 static void    bswap32_region(int32_t* , int);
94 static void    elf_read_syms(struct elf_syms *, int, off_t, off_t, off_t,
95     off_t);
96 
97 
98 int
99 main(int argc, char **argv)
100 {
101 	Elf32_Ehdr ex;
102 	Elf32_Phdr *ph;
103 	Elf32_Shdr *sh;
104 	char   *shstrtab;
105 	int     strtabix, symtabix;
106 	size_t	i;
107 	int     pad;
108 	struct sect text, data, bss;	/* a.out-compatible sections */
109 	struct sect rdata, sdata, sbss;	/* ECOFF-only sections */
110 
111 	struct ecoff_exechdr ep;
112 	struct ecoff_scnhdr esecs[6];
113 	struct ecoff_symhdr symhdr;
114 
115 	int     infile, outfile;
116 	unsigned long cur_vma = ULONG_MAX;
117 	int     symflag = 0;
118 	int     nsecs = 0;
119 	int	mipsel;
120 
121 
122 	text.len = data.len = bss.len = 0;
123 	text.vaddr = data.vaddr = bss.vaddr = 0;
124 
125 	rdata.len = sdata.len = sbss.len = 0;
126 	rdata.vaddr = sdata.vaddr = sbss.vaddr = 0;
127 
128 	/* Check args... */
129 	if (argc < 3 || argc > 4) {
130 usage:
131 		fprintf(stderr,
132 		    "Usage: %s <elf executable> <ECOFF executable> [-s]\n",
133 		    getprogname());
134 		exit(1);
135 	}
136 	if (argc == 4) {
137 		if (strcmp(argv[3], "-s"))
138 			goto usage;
139 		symflag = 1;
140 	}
141 	/* Try the input file... */
142 	if ((infile = open(argv[1], O_RDONLY)) < 0)
143 		err(1, "Can't open %s for read", argv[1]);
144 	/* Read the header, which is at the beginning of the file... */
145 	i = read(infile, &ex, sizeof ex);
146 	if (i != sizeof ex)
147 		err(1, "Short header read from %s", argv[1]);
148 	if (ex.e_ident[EI_DATA] == ELFDATA2LSB)
149 		mipsel = 1;
150 	else if (ex.e_ident[EI_DATA] == ELFDATA2MSB)
151 		mipsel = 0;
152 	else
153 		errx(1, "invalid ELF byte order %d", ex.e_ident[EI_DATA]);
154 #if BYTE_ORDER == BIG_ENDIAN
155 	if (mipsel)
156 		needswap = 1;
157 	else
158 		needswap = 0;
159 #elif BYTE_ORDER == LITTLE_ENDIAN
160 	if (mipsel)
161 		needswap = 0;
162 	else
163 		needswap = 1;
164 #else
165 #error "unknown endian"
166 #endif
167 
168 	if (needswap) {
169 		ex.e_type	= bswap16(ex.e_type);
170 		ex.e_machine	= bswap16(ex.e_machine);
171 		ex.e_version	= bswap32(ex.e_version);
172 		ex.e_entry 	= bswap32(ex.e_entry);
173 		ex.e_phoff	= bswap32(ex.e_phoff);
174 		ex.e_shoff	= bswap32(ex.e_shoff);
175 		ex.e_flags	= bswap32(ex.e_flags);
176 		ex.e_ehsize	= bswap16(ex.e_ehsize);
177 		ex.e_phentsize	= bswap16(ex.e_phentsize);
178 		ex.e_phnum	= bswap16(ex.e_phnum);
179 		ex.e_shentsize	= bswap16(ex.e_shentsize);
180 		ex.e_shnum	= bswap16(ex.e_shnum);
181 		ex.e_shstrndx	= bswap16(ex.e_shstrndx);
182 	}
183 
184 	/* Read the program headers... */
185 	ph = (Elf32_Phdr *) saveRead(infile, ex.e_phoff,
186 	    ex.e_phnum * sizeof(Elf32_Phdr), "ph");
187 	if (needswap)
188 		bswap32_region((int32_t*)ph, sizeof(Elf32_Phdr) * ex.e_phnum);
189 	/* Read the section headers... */
190 	sh = (Elf32_Shdr *) saveRead(infile, ex.e_shoff,
191 	    ex.e_shnum * sizeof(Elf32_Shdr), "sh");
192 	if (needswap)
193 		bswap32_region((int32_t*)sh, sizeof(Elf32_Shdr) * ex.e_shnum);
194 
195 	/* Read in the section string table. */
196 	shstrtab = saveRead(infile, sh[ex.e_shstrndx].sh_offset,
197 	    sh[ex.e_shstrndx].sh_size, "shstrtab");
198 
199 
200 	/* Look for the symbol table and string table... Also map section
201 	 * indices to symbol types for a.out */
202 	symtabix = 0;
203 	strtabix = 0;
204 	for (i = 0; i < ex.e_shnum; i++) {
205 		char   *name = shstrtab + sh[i].sh_name;
206 		if (!strcmp(name, ".symtab"))
207 			symtabix = i;
208 		else
209 			if (!strcmp(name, ".strtab"))
210 				strtabix = i;
211 
212 	}
213 
214 	/*
215 	 * Figure out if we can cram the program header into an ECOFF
216 	 * header...  Basically, we can't handle anything but loadable
217 	 * segments, but we can ignore some kinds of segments.  We can't
218 	 * handle holes in the address space.  Segments may be out of order,
219 	 * so we sort them first.
220 	 */
221 
222 	qsort(ph, ex.e_phnum, sizeof(Elf32_Phdr),
223 	    (int (*) (const void *, const void *)) phcmp);
224 
225 	for (i = 0; i < ex.e_phnum; i++) {
226 		/* Section types we can ignore... */
227 		if (ph[i].p_type == PT_NULL || ph[i].p_type == PT_NOTE ||
228 		    ph[i].p_type == PT_PHDR ||
229 		    ph[i].p_type == PT_MIPS_REGINFO) {
230 
231 			if (debug) {
232 				fprintf(stderr, "  skipping PH %zu type %d "
233 				    "flags 0x%x\n",
234 				    i, ph[i].p_type, ph[i].p_flags);
235 			}
236 			continue;
237 		}
238 		/* Section types we can't handle... */
239 		else
240 			if (ph[i].p_type != PT_LOAD)
241 				errx(1, "Program header %zu type %d can't be "
242 				    "converted", i, ph[i].p_type);
243 		/* Writable (data) segment? */
244 		if (ph[i].p_flags & PF_W) {
245 			struct sect ndata, nbss;
246 
247 			ndata.vaddr = ph[i].p_vaddr;
248 			ndata.len = ph[i].p_filesz;
249 			nbss.vaddr = ph[i].p_vaddr + ph[i].p_filesz;
250 			nbss.len = ph[i].p_memsz - ph[i].p_filesz;
251 
252 			if (debug) {
253 				fprintf(stderr, "  combinining PH %zu type %d "
254 				    "flags 0x%x with data, ndata = %ld, "
255 				    "nbss =%ld\n", i, ph[i].p_type,
256 				    ph[i].p_flags, ndata.len, nbss.len);
257 			}
258 			combine(&data, &ndata, 0);
259 			combine(&bss, &nbss, 1);
260 		} else {
261 			struct sect ntxt;
262 
263 			ntxt.vaddr = ph[i].p_vaddr;
264 			ntxt.len = ph[i].p_filesz;
265 			if (debug) {
266 				fprintf(stderr, "  combinining PH %zu type %d "
267 				    "flags 0x%x with text, len = %ld\n",
268 				    i, ph[i].p_type, ph[i].p_flags, ntxt.len);
269 			}
270 			combine(&text, &ntxt, 0);
271 		}
272 		/* Remember the lowest segment start address. */
273 		if (ph[i].p_vaddr < cur_vma)
274 			cur_vma = ph[i].p_vaddr;
275 	}
276 
277 	/* Sections must be in order to be converted... */
278 	if (text.vaddr > data.vaddr || data.vaddr > bss.vaddr ||
279 	    text.vaddr + text.len > data.vaddr ||
280 	    data.vaddr + data.len > bss.vaddr)
281 		errx(1, "Sections ordering prevents a.out conversion");
282 	/* If there's a data section but no text section, then the loader
283 	 * combined everything into one section.   That needs to be the text
284 	 * section, so just make the data section zero length following text. */
285 	if (data.len && text.len == 0) {
286 		text = data;
287 		data.vaddr = text.vaddr + text.len;
288 		data.len = 0;
289 	}
290 	/* If there is a gap between text and data, we'll fill it when we copy
291 	 * the data, so update the length of the text segment as represented
292 	 * in a.out to reflect that, since a.out doesn't allow gaps in the
293 	 * program address space. */
294 	if (text.vaddr + text.len < data.vaddr)
295 		text.len = data.vaddr - text.vaddr;
296 
297 	/* We now have enough information to cons up an a.out header... */
298 	ep.a.magic = ECOFF_OMAGIC;
299 	ep.a.vstamp = 2 * 256 + 10;	/* compatible with version 2.10 */
300 	ep.a.tsize = text.len;
301 	ep.a.dsize = data.len;
302 	ep.a.bsize = bss.len;
303 	ep.a.entry = ex.e_entry;
304 	ep.a.text_start = text.vaddr;
305 	ep.a.data_start = data.vaddr;
306 	ep.a.bss_start = bss.vaddr;
307 	ep.a.gprmask = 0xf3fffffe;
308 	memset(&ep.a.cprmask, 0, sizeof ep.a.cprmask);
309 	ep.a.gp_value = 0;	/* unused. */
310 
311 	if (mipsel)
312 		ep.f.f_magic = ECOFF_MAGIC_MIPSEL;
313 	else
314 		ep.f.f_magic = ECOFF_MAGIC_MIPSEB;
315 
316 	ep.f.f_nscns = 6;
317 	ep.f.f_timdat = 0;	/* bogus */
318 	ep.f.f_symptr = 0;
319 	ep.f.f_nsyms = sizeof(struct ecoff_symhdr);
320 	ep.f.f_opthdr = sizeof ep.a;
321 	ep.f.f_flags = 0x100f;	/* Stripped, not sharable. */
322 
323 	memset(esecs, 0, sizeof(esecs));
324 
325 	/* Make  ECOFF section headers, with empty stubs for
326 	 * .rdata/.sdata/.sbss. */
327 	make_ecoff_section_hdrs(&ep, esecs);
328 
329 	nsecs = ep.f.f_nscns;
330 
331 	if (needswap) {
332 		ep.f.f_magic	= bswap16(ep.f.f_magic);
333 		ep.f.f_nscns	= bswap16(ep.f.f_nscns);
334 		ep.f.f_timdat	= bswap32(ep.f.f_timdat);
335 		ep.f.f_symptr	= bswap32(ep.f.f_symptr);
336 		ep.f.f_nsyms	= bswap32(ep.f.f_nsyms);
337 		ep.f.f_opthdr	= bswap16(ep.f.f_opthdr);
338 		ep.f.f_flags	= bswap16(ep.f.f_flags);
339 		ep.a.magic	= bswap16(ep.a.magic);
340 		ep.a.vstamp	= bswap16(ep.a.vstamp);
341 		ep.a.tsize	= bswap32(ep.a.tsize);
342 		ep.a.dsize	= bswap32(ep.a.dsize);
343 		ep.a.bsize	= bswap32(ep.a.bsize);
344 		ep.a.entry	= bswap32(ep.a.entry);
345 		ep.a.text_start	= bswap32(ep.a.text_start);
346 		ep.a.data_start	= bswap32(ep.a.data_start);
347 		ep.a.bss_start	= bswap32(ep.a.bss_start);
348 		ep.a.gprmask	= bswap32(ep.a.gprmask);
349 		bswap32_region((int32_t*)ep.a.cprmask, sizeof(ep.a.cprmask));
350 		ep.a.gp_value	= bswap32(ep.a.gp_value);
351 		for (i = 0; i < sizeof(esecs) / sizeof(esecs[0]); i++) {
352 			esecs[i].s_paddr	= bswap32(esecs[i].s_paddr);
353 			esecs[i].s_vaddr	= bswap32(esecs[i].s_vaddr);
354 			esecs[i].s_size 	= bswap32(esecs[i].s_size);
355 			esecs[i].s_scnptr	= bswap32(esecs[i].s_scnptr);
356 			esecs[i].s_relptr	= bswap32(esecs[i].s_relptr);
357 			esecs[i].s_lnnoptr	= bswap32(esecs[i].s_lnnoptr);
358 			esecs[i].s_nreloc	= bswap16(esecs[i].s_nreloc);
359 			esecs[i].s_nlnno	= bswap16(esecs[i].s_nlnno);
360 			esecs[i].s_flags	= bswap32(esecs[i].s_flags);
361 		}
362 	}
363 
364 	/* Make the output file... */
365 	if ((outfile = open(argv[2], O_WRONLY | O_CREAT, 0777)) < 0)
366 		err(1, "Unable to create %s", argv[2]);
367 
368 	/* Truncate file... */
369 	if (ftruncate(outfile, 0)) {
370 		warn("ftruncate %s", argv[2]);
371 	}
372 	/* Write the headers... */
373 	safewrite(outfile, &ep.f, sizeof(ep.f), "ep.f: write");
374 	if (debug)
375 		fprintf(stderr, "wrote %zu byte file header.\n", sizeof(ep.f));
376 
377 	safewrite(outfile, &ep.a, sizeof(ep.a), "ep.a: write");
378 	if (debug)
379 		fprintf(stderr, "wrote %zu byte a.out header.\n", sizeof(ep.a));
380 
381 	safewrite(outfile, &esecs, sizeof(esecs[0]) * nsecs, "esecs: write");
382 	if (debug)
383 		fprintf(stderr, "wrote %zu bytes of section headers.\n",
384 		    sizeof(esecs[0]) * nsecs);
385 
386 
387 	pad = ((sizeof ep.f + sizeof ep.a + sizeof esecs) & 15);
388 	if (pad) {
389 		pad = 16 - pad;
390 		pad16(outfile, pad, "ipad: write");
391 		if (debug)
392 			fprintf(stderr, "wrote %d byte pad.\n", pad);
393 	}
394 	/* Copy the loadable sections.   Zero-fill any gaps less than 64k;
395 	 * complain about any zero-filling, and die if we're asked to
396 	 * zero-fill more than 64k. */
397 	for (i = 0; i < ex.e_phnum; i++) {
398 		/* Unprocessable sections were handled above, so just verify
399 		 * that the section can be loaded before copying. */
400 		if (ph[i].p_type == PT_LOAD && ph[i].p_filesz) {
401 			if (cur_vma != ph[i].p_vaddr) {
402 				unsigned long gap = ph[i].p_vaddr - cur_vma;
403 				char    obuf[1024];
404 				if (gap > 65536)
405 					errx(1, "Intersegment gap (%ld bytes) "
406 					    "too large", gap);
407 				if (debug)
408 					fprintf(stderr, "Warning: %ld byte "
409 					    "intersegment gap.\n", gap);
410 				memset(obuf, 0, sizeof obuf);
411 				while (gap) {
412 					int count = write(outfile, obuf,
413 					    (gap > sizeof obuf
414 					    ? sizeof obuf : gap));
415 					if (count < 0)
416 						err(1, "Error writing gap");
417 					gap -= count;
418 				}
419 			}
420 			if (debug)
421 				fprintf(stderr, "writing %d bytes...\n",
422 				    ph[i].p_filesz);
423 			copy(outfile, infile, ph[i].p_offset, ph[i].p_filesz);
424 			cur_vma = ph[i].p_vaddr + ph[i].p_filesz;
425 		}
426 	}
427 
428 
429 	if (debug)
430 		fprintf(stderr, "writing syms at offset 0x%lx\n",
431 		    (u_long) ep.f.f_symptr + sizeof(symhdr));
432 
433 	/* Copy and translate the symbol table... */
434 	elf_symbol_table_to_ecoff(outfile, infile, &ep,
435 	    sh[symtabix].sh_offset, sh[symtabix].sh_size,
436 	    sh[strtabix].sh_offset, sh[strtabix].sh_size);
437 
438 	/*
439          * Write a page of padding for boot PROMS that read entire pages.
440          * Without this, they may attempt to read past the end of the
441          * data section, incur an error, and refuse to boot.
442          */
443 	{
444 		char    obuf[4096];
445 		memset(obuf, 0, sizeof obuf);
446 		if (write(outfile, obuf, sizeof(obuf)) != sizeof(obuf))
447 			err(1, "Error writing PROM padding");
448 	}
449 
450 	/* Looks like we won... */
451 	return 0;
452 }
453 
454 static void
455 copy(int out, int in, off_t offset, off_t size)
456 {
457 	char    ibuf[4096];
458 	size_t  remaining, cur, count;
459 
460 	/* Go to the start of the ELF symbol table... */
461 	if (lseek(in, offset, SEEK_SET) < 0)
462 		err(1, "copy: lseek");
463 	remaining = size;
464 	while (remaining) {
465 		cur = remaining;
466 		if (cur > sizeof ibuf)
467 			cur = sizeof ibuf;
468 		remaining -= cur;
469 		if ((count = read(in, ibuf, cur)) != cur)
470 			err(1, "copy: short read");
471 		safewrite(out, ibuf, cur, "copy: write");
472 	}
473 }
474 
475 /* Combine two segments, which must be contiguous.   If pad is true, it's
476    okay for there to be padding between. */
477 static void
478 combine(struct sect *base, struct sect *new, int pad)
479 {
480 
481 	if (base->len == 0)
482 		*base = *new;
483 	else
484 		if (new->len) {
485 			if (base->vaddr + base->len != new->vaddr) {
486 				if (pad)
487 					base->len = new->vaddr - base->vaddr;
488 				else
489 					errx(1, "Non-contiguous data can't be "
490 					    "converted");
491 			}
492 			base->len += new->len;
493 		}
494 }
495 
496 static int
497 phcmp(Elf32_Phdr *h1, Elf32_Phdr *h2)
498 {
499 
500 	if (h1->p_vaddr > h2->p_vaddr)
501 		return 1;
502 	else
503 		if (h1->p_vaddr < h2->p_vaddr)
504 			return -1;
505 		else
506 			return 0;
507 }
508 
509 static char *
510 saveRead(int file, off_t offset, off_t len, const char *name)
511 {
512 	char   *tmp;
513 	int     count;
514 	off_t   off;
515 
516 	if ((off = lseek(file, offset, SEEK_SET)) < 0)
517 		err(1, "%s: fseek", name);
518 	if ((tmp = malloc(len)) == NULL)
519 		err(1, "%s: Can't allocate %ld bytes", name, (long) len);
520 	count = read(file, tmp, len);
521 	if (count != len)
522 		err(1, "%s: short read", name);
523 	return tmp;
524 }
525 
526 static void
527 safewrite(int outfile, const void *buf, off_t len, const char *msg)
528 {
529 	ssize_t     written;
530 
531 	written = write(outfile, buf, len);
532 	if (written != len)
533 		err(1, "%s", msg);
534 }
535 
536 
537 /*
538  * Output only three ECOFF sections, corresponding to ELF psecs
539  * for text, data, and bss.
540  */
541 static int
542 make_ecoff_section_hdrs(struct ecoff_exechdr *ep, struct ecoff_scnhdr *esecs)
543 {
544 
545 	ep->f.f_nscns = 6;	/* XXX */
546 
547 	strcpy(esecs[0].s_name, ".text");
548 	strcpy(esecs[1].s_name, ".data");
549 	strcpy(esecs[2].s_name, ".bss");
550 
551 	esecs[0].s_paddr = esecs[0].s_vaddr = ep->a.text_start;
552 	esecs[1].s_paddr = esecs[1].s_vaddr = ep->a.data_start;
553 	esecs[2].s_paddr = esecs[2].s_vaddr = ep->a.bss_start;
554 	esecs[0].s_size = ep->a.tsize;
555 	esecs[1].s_size = ep->a.dsize;
556 	esecs[2].s_size = ep->a.bsize;
557 
558 	esecs[0].s_scnptr = ECOFF_TXTOFF(ep);
559 	esecs[1].s_scnptr = ECOFF_DATOFF(ep);
560 #if 0
561 	esecs[2].s_scnptr = esecs[1].s_scnptr +
562 	    ECOFF_ROUND(esecs[1].s_size, ECOFF_SEGMENT_ALIGNMENT(ep));
563 #endif
564 
565 	esecs[0].s_relptr = esecs[1].s_relptr = esecs[2].s_relptr = 0;
566 	esecs[0].s_lnnoptr = esecs[1].s_lnnoptr = esecs[2].s_lnnoptr = 0;
567 	esecs[0].s_nreloc = esecs[1].s_nreloc = esecs[2].s_nreloc = 0;
568 	esecs[0].s_nlnno = esecs[1].s_nlnno = esecs[2].s_nlnno = 0;
569 
570 	esecs[1].s_flags = 0x100;	/* ECOFF rdata */
571 	esecs[3].s_flags = 0x200;	/* ECOFF sdata */
572 	esecs[4].s_flags = 0x400;	/* ECOFF sbss */
573 
574 	/*
575 	 * Set the symbol-table offset  to point at the end of any
576 	 * sections we loaded above, so later code can use it to write
577 	 * symbol table info..
578 	 */
579 	ep->f.f_symptr = esecs[1].s_scnptr + esecs[1].s_size;
580 	return (ep->f.f_nscns);
581 }
582 
583 
584 /*
585  * Write the ECOFF symbol header.
586  * Guess at how big the symbol table will be.
587  * Mark all symbols as EXTERN (for now).
588  */
589 static void
590 write_ecoff_symhdr(int out, struct ecoff_exechdr *ep,
591     struct ecoff_symhdr *symhdrp, long nesyms,
592     long extsymoff, long extstroff, long strsize)
593 {
594 
595 	if (debug)
596 		fprintf(stderr,
597 		    "writing symhdr for %ld entries at offset 0x%lx\n",
598 		    nesyms, (u_long) ep->f.f_symptr);
599 
600 	ep->f.f_nsyms = sizeof(struct ecoff_symhdr);
601 
602 	memset(symhdrp, 0, sizeof(*symhdrp));
603 	symhdrp->esymMax = nesyms;
604 	symhdrp->magic = 0x7009;/* XXX */
605 	symhdrp->cbExtOffset = extsymoff;
606 	symhdrp->cbSsExtOffset = extstroff;
607 
608 	symhdrp->issExtMax = strsize;
609 	if (debug)
610 		fprintf(stderr,
611 		    "ECOFF symhdr: symhdr %zx, strsize %lx, symsize %lx\n",
612 		    sizeof(*symhdrp), strsize,
613 		    (nesyms * sizeof(struct ecoff_extsym)));
614 
615 	if (needswap) {
616 		bswap32_region(&symhdrp->ilineMax,
617 		    sizeof(*symhdrp) -  sizeof(symhdrp->magic) -
618 		    sizeof(symhdrp->ilineMax));
619 		symhdrp->magic = bswap16(symhdrp->magic);
620 		symhdrp->ilineMax = bswap16(symhdrp->ilineMax);
621 	}
622 
623 	safewrite(out, symhdrp, sizeof(*symhdrp),
624 	    "writing symbol header");
625 }
626 
627 
628 static void
629 elf_read_syms(struct elf_syms *elfsymsp, int in, off_t symoff, off_t symsize,
630     off_t stroff, off_t strsize)
631 {
632 	register int nsyms;
633 	int i;
634 	nsyms = symsize / sizeof(Elf32_Sym);
635 
636 	/* Suck in the ELF symbol list... */
637 	elfsymsp->elf_syms = (Elf32_Sym *)
638 	    saveRead(in, symoff, nsyms * sizeof(Elf32_Sym),
639 	    "ELF symboltable");
640 	elfsymsp->nsymbols = nsyms;
641 	if (needswap) {
642 		for (i = 0; i < nsyms; i++) {
643 			Elf32_Sym *s = &elfsymsp->elf_syms[i];
644 			s->st_name	= bswap32(s->st_name);
645 			s->st_value	= bswap32(s->st_value);
646 			s->st_size	= bswap32(s->st_size);
647 			s->st_shndx	= bswap16(s->st_shndx);
648 		}
649 	}
650 
651 	/* Suck in the ELF string table... */
652 	elfsymsp->stringtab = (char *)
653 	    saveRead(in, stroff, strsize, "ELF string table");
654 	elfsymsp->stringsize = strsize;
655 }
656 
657 
658 static void
659 elf_symbol_table_to_ecoff(int out, int in, struct ecoff_exechdr *ep,
660     off_t symoff, off_t symsize, off_t stroff, off_t strsize)
661 {
662 
663 	struct elf_syms elfsymtab;
664 	struct ecoff_syms ecoffsymtab;
665 	register u_long ecoff_symhdr_off, symtaboff, stringtaboff;
666 	register u_long nextoff, symtabsize, ecoff_strsize;
667 	int     nsyms, i;
668 	struct ecoff_symhdr symhdr;
669 	int     padding;
670 
671 	/* Read in the ELF symbols. */
672 	elf_read_syms(&elfsymtab, in, symoff, symsize, stroff, strsize);
673 
674 	/* Approximate translation to ECOFF. */
675 	translate_syms(&elfsymtab, &ecoffsymtab);
676 	nsyms = ecoffsymtab.nsymbols;
677 
678 	/* Compute output ECOFF symbol- and string-table offsets. */
679 	ecoff_symhdr_off = ep->f.f_symptr;
680 
681 	nextoff = ecoff_symhdr_off + sizeof(struct ecoff_symhdr);
682 	stringtaboff = nextoff;
683 	ecoff_strsize = ECOFF_ROUND(ecoffsymtab.stringsize,
684 	    (ECOFF_SEGMENT_ALIGNMENT(ep)));
685 
686 
687 	nextoff = stringtaboff + ecoff_strsize;
688 	symtaboff = nextoff;
689 	symtabsize = nsyms * sizeof(struct ecoff_extsym);
690 	symtabsize = ECOFF_ROUND(symtabsize, ECOFF_SEGMENT_ALIGNMENT(ep));
691 
692 	/* Write out the symbol header ... */
693 	write_ecoff_symhdr(out, ep, &symhdr, nsyms, symtaboff,
694 	    stringtaboff, ecoffsymtab.stringsize);
695 
696 	/* Write out the string table... */
697 	padding = ecoff_strsize - ecoffsymtab.stringsize;
698 	safewrite(out, ecoffsymtab.stringtab, ecoffsymtab.stringsize,
699 	    "string table: write");
700 	if (padding)
701 		pad16(out, padding, "string table: padding");
702 
703 
704 	/* Write out the symbol table... */
705 	padding = symtabsize - (nsyms * sizeof(struct ecoff_extsym));
706 
707 	for (i = 0; i < nsyms; i++) {
708 		struct ecoff_extsym *es = &ecoffsymtab.ecoff_syms[i];
709 		es->es_flags	= bswap16(es->es_flags);
710 		es->es_ifd	= bswap16(es->es_ifd);
711 		bswap32_region(&es->es_strindex,
712 		    sizeof(*es) - sizeof(es->es_flags) - sizeof(es->es_ifd));
713 	}
714 	safewrite(out, ecoffsymtab.ecoff_syms,
715 	    nsyms * sizeof(struct ecoff_extsym),
716 	    "symbol table: write");
717 	if (padding)
718 		pad16(out, padding, "symbols: padding");
719 }
720 
721 
722 
723 /*
724  * In-memory translation of ELF symbosl to ECOFF.
725  */
726 static void
727 translate_syms(struct elf_syms *elfp, struct ecoff_syms *ecoffp)
728 {
729 
730 	int     i;
731 	char   *oldstringbase;
732 	char   *newstrings, *nsp;
733 
734 	int     nsyms, idx;
735 
736 	nsyms = elfp->nsymbols;
737 	oldstringbase = elfp->stringtab;
738 
739 	/* Allocate space for corresponding ECOFF symbols. */
740 	memset(ecoffp, 0, sizeof(*ecoffp));
741 
742 	ecoffp->nsymbols = 0;
743 	ecoffp->ecoff_syms = malloc(sizeof(struct ecoff_extsym) * nsyms);
744 
745 	/* we are going to be no bigger than the ELF symbol table. */
746 	ecoffp->stringsize = elfp->stringsize;
747 	ecoffp->stringtab = malloc(elfp->stringsize);
748 
749 	newstrings = (char *) ecoffp->stringtab;
750 	nsp = (char *) ecoffp->stringtab;
751 	if (newstrings == NULL)
752 		errx(1, "No memory for new string table");
753 	/* Copy and translate  symbols... */
754 	idx = 0;
755 	for (i = 0; i < nsyms; i++) {
756 		int     binding, type;
757 
758 		binding = ELF32_ST_BIND((elfp->elf_syms[i].st_info));
759 		type = ELF32_ST_TYPE((elfp->elf_syms[i].st_info));
760 
761 		/* skip strange symbols */
762 		if (binding == 0) {
763 			continue;
764 		}
765 		/* Copy the symbol into the new table */
766 		strcpy(nsp, oldstringbase + elfp->elf_syms[i].st_name);
767 		ecoffp->ecoff_syms[idx].es_strindex = nsp - newstrings;
768 		nsp += strlen(nsp) + 1;
769 
770 		/* translate symbol types to ECOFF XXX */
771 		ecoffp->ecoff_syms[idx].es_type = 1;
772 		ecoffp->ecoff_syms[idx].es_class = 5;
773 
774 		/* Symbol values in executables should be compatible. */
775 		ecoffp->ecoff_syms[idx].es_value = elfp->elf_syms[i].st_value;
776 		ecoffp->ecoff_syms[idx].es_symauxindex = 0xfffff;
777 
778 		idx++;
779 	}
780 
781 	ecoffp->nsymbols = idx;
782 	ecoffp->stringsize = nsp - newstrings;
783 }
784 /*
785  * pad to a 16-byte boundary
786  */
787 static void
788 pad16(int fd, int size, const char *msg)
789 {
790 
791 	safewrite(fd, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0", size, msg);
792 }
793 
794 /* swap a 32bit region */
795 static void
796 bswap32_region(int32_t* p, int len)
797 {
798 	size_t i;
799 
800 	for (i = 0; i < len / sizeof(int32_t); i++, p++)
801 		*p = bswap32(*p);
802 }
803