xref: /netbsd-src/usr.bin/elf2ecoff/elf2ecoff.c (revision 6a493d6bc668897c91594964a732d38505b70cbb)
1 /*	$NetBSD: elf2ecoff.c,v 1.29 2013/11/10 17:14:25 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 
110 	struct ecoff_exechdr ep;
111 	struct ecoff_scnhdr esecs[6];
112 	struct ecoff_symhdr symhdr;
113 
114 	int     infile, outfile;
115 	unsigned long cur_vma = ULONG_MAX;
116 	int     nsecs = 0;
117 	int	mipsel;
118 
119 
120 	text.len = data.len = bss.len = 0;
121 	text.vaddr = data.vaddr = bss.vaddr = 0;
122 
123 	/* Check args... */
124 	if (argc < 3 || argc > 4) {
125 usage:
126 		fprintf(stderr,
127 		    "Usage: %s <elf executable> <ECOFF executable> [-s]\n",
128 		    getprogname());
129 		exit(1);
130 	}
131 	if (argc == 4) {
132 		if (strcmp(argv[3], "-s"))
133 			goto usage;
134 	}
135 	/* Try the input file... */
136 	if ((infile = open(argv[1], O_RDONLY)) < 0)
137 		err(1, "Can't open %s for read", argv[1]);
138 	/* Read the header, which is at the beginning of the file... */
139 	i = read(infile, &ex, sizeof ex);
140 	if (i != sizeof ex)
141 		err(1, "Short header read from %s", argv[1]);
142 	if (ex.e_ident[EI_DATA] == ELFDATA2LSB)
143 		mipsel = 1;
144 	else if (ex.e_ident[EI_DATA] == ELFDATA2MSB)
145 		mipsel = 0;
146 	else
147 		errx(1, "invalid ELF byte order %d", ex.e_ident[EI_DATA]);
148 #if BYTE_ORDER == BIG_ENDIAN
149 	if (mipsel)
150 		needswap = 1;
151 	else
152 		needswap = 0;
153 #elif BYTE_ORDER == LITTLE_ENDIAN
154 	if (mipsel)
155 		needswap = 0;
156 	else
157 		needswap = 1;
158 #else
159 #error "unknown endian"
160 #endif
161 
162 	if (needswap) {
163 		ex.e_type	= bswap16(ex.e_type);
164 		ex.e_machine	= bswap16(ex.e_machine);
165 		ex.e_version	= bswap32(ex.e_version);
166 		ex.e_entry 	= bswap32(ex.e_entry);
167 		ex.e_phoff	= bswap32(ex.e_phoff);
168 		ex.e_shoff	= bswap32(ex.e_shoff);
169 		ex.e_flags	= bswap32(ex.e_flags);
170 		ex.e_ehsize	= bswap16(ex.e_ehsize);
171 		ex.e_phentsize	= bswap16(ex.e_phentsize);
172 		ex.e_phnum	= bswap16(ex.e_phnum);
173 		ex.e_shentsize	= bswap16(ex.e_shentsize);
174 		ex.e_shnum	= bswap16(ex.e_shnum);
175 		ex.e_shstrndx	= bswap16(ex.e_shstrndx);
176 	}
177 
178 	/* Read the program headers... */
179 	ph = (Elf32_Phdr *) saveRead(infile, ex.e_phoff,
180 	    ex.e_phnum * sizeof(Elf32_Phdr), "ph");
181 	if (needswap)
182 		bswap32_region((int32_t*)ph, sizeof(Elf32_Phdr) * ex.e_phnum);
183 	/* Read the section headers... */
184 	sh = (Elf32_Shdr *) saveRead(infile, ex.e_shoff,
185 	    ex.e_shnum * sizeof(Elf32_Shdr), "sh");
186 	if (needswap)
187 		bswap32_region((int32_t*)sh, sizeof(Elf32_Shdr) * ex.e_shnum);
188 
189 	/* Read in the section string table. */
190 	shstrtab = saveRead(infile, sh[ex.e_shstrndx].sh_offset,
191 	    sh[ex.e_shstrndx].sh_size, "shstrtab");
192 
193 
194 	/* Look for the symbol table and string table... Also map section
195 	 * indices to symbol types for a.out */
196 	symtabix = 0;
197 	strtabix = 0;
198 	for (i = 0; i < ex.e_shnum; i++) {
199 		char   *name = shstrtab + sh[i].sh_name;
200 		if (!strcmp(name, ".symtab"))
201 			symtabix = i;
202 		else
203 			if (!strcmp(name, ".strtab"))
204 				strtabix = i;
205 
206 	}
207 
208 	/*
209 	 * Figure out if we can cram the program header into an ECOFF
210 	 * header...  Basically, we can't handle anything but loadable
211 	 * segments, but we can ignore some kinds of segments.  We can't
212 	 * handle holes in the address space.  Segments may be out of order,
213 	 * so we sort them first.
214 	 */
215 
216 	qsort(ph, ex.e_phnum, sizeof(Elf32_Phdr),
217 	    (int (*) (const void *, const void *)) phcmp);
218 
219 	for (i = 0; i < ex.e_phnum; i++) {
220 		/* Section types we can ignore... */
221 		if (ph[i].p_type == PT_NULL || ph[i].p_type == PT_NOTE ||
222 		    ph[i].p_type == PT_PHDR ||
223 		    ph[i].p_type == PT_MIPS_REGINFO) {
224 
225 			if (debug) {
226 				fprintf(stderr, "  skipping PH %zu type %d "
227 				    "flags 0x%x\n",
228 				    i, ph[i].p_type, ph[i].p_flags);
229 			}
230 			continue;
231 		}
232 		/* Section types we can't handle... */
233 		else
234 			if (ph[i].p_type != PT_LOAD)
235 				errx(1, "Program header %zu type %d can't be "
236 				    "converted", i, ph[i].p_type);
237 		/* Writable (data) segment? */
238 		if (ph[i].p_flags & PF_W) {
239 			struct sect ndata, nbss;
240 
241 			ndata.vaddr = ph[i].p_vaddr;
242 			ndata.len = ph[i].p_filesz;
243 			nbss.vaddr = ph[i].p_vaddr + ph[i].p_filesz;
244 			nbss.len = ph[i].p_memsz - ph[i].p_filesz;
245 
246 			if (debug) {
247 				fprintf(stderr, "  combinining PH %zu type %d "
248 				    "flags 0x%x with data, ndata = %ld, "
249 				    "nbss =%ld\n", i, ph[i].p_type,
250 				    ph[i].p_flags, ndata.len, nbss.len);
251 			}
252 			combine(&data, &ndata, 0);
253 			combine(&bss, &nbss, 1);
254 		} else {
255 			struct sect ntxt;
256 
257 			ntxt.vaddr = ph[i].p_vaddr;
258 			ntxt.len = ph[i].p_filesz;
259 			if (debug) {
260 				fprintf(stderr, "  combinining PH %zu type %d "
261 				    "flags 0x%x with text, len = %ld\n",
262 				    i, ph[i].p_type, ph[i].p_flags, ntxt.len);
263 			}
264 			combine(&text, &ntxt, 0);
265 		}
266 		/* Remember the lowest segment start address. */
267 		if (ph[i].p_vaddr < cur_vma)
268 			cur_vma = ph[i].p_vaddr;
269 	}
270 
271 	/* Sections must be in order to be converted... */
272 	if (text.vaddr > data.vaddr || data.vaddr > bss.vaddr ||
273 	    text.vaddr + text.len > data.vaddr ||
274 	    data.vaddr + data.len > bss.vaddr)
275 		errx(1, "Sections ordering prevents a.out conversion");
276 	/* If there's a data section but no text section, then the loader
277 	 * combined everything into one section.   That needs to be the text
278 	 * section, so just make the data section zero length following text. */
279 	if (data.len && text.len == 0) {
280 		text = data;
281 		data.vaddr = text.vaddr + text.len;
282 		data.len = 0;
283 	}
284 	/* If there is a gap between text and data, we'll fill it when we copy
285 	 * the data, so update the length of the text segment as represented
286 	 * in a.out to reflect that, since a.out doesn't allow gaps in the
287 	 * program address space. */
288 	if (text.vaddr + text.len < data.vaddr)
289 		text.len = data.vaddr - text.vaddr;
290 
291 	/* We now have enough information to cons up an a.out header... */
292 	ep.a.magic = ECOFF_OMAGIC;
293 	ep.a.vstamp = 2 * 256 + 10;	/* compatible with version 2.10 */
294 	ep.a.tsize = text.len;
295 	ep.a.dsize = data.len;
296 	ep.a.bsize = bss.len;
297 	ep.a.entry = ex.e_entry;
298 	ep.a.text_start = text.vaddr;
299 	ep.a.data_start = data.vaddr;
300 	ep.a.bss_start = bss.vaddr;
301 	ep.a.gprmask = 0xf3fffffe;
302 	memset(&ep.a.cprmask, 0, sizeof ep.a.cprmask);
303 	ep.a.gp_value = 0;	/* unused. */
304 
305 	if (mipsel)
306 		ep.f.f_magic = ECOFF_MAGIC_MIPSEL;
307 	else
308 		ep.f.f_magic = ECOFF_MAGIC_MIPSEB;
309 
310 	ep.f.f_nscns = 6;
311 	ep.f.f_timdat = 0;	/* bogus */
312 	ep.f.f_symptr = 0;
313 	ep.f.f_nsyms = sizeof(struct ecoff_symhdr);
314 	ep.f.f_opthdr = sizeof ep.a;
315 	ep.f.f_flags = 0x100f;	/* Stripped, not sharable. */
316 
317 	memset(esecs, 0, sizeof(esecs));
318 
319 	/* Make  ECOFF section headers, with empty stubs for
320 	 * .rdata/.sdata/.sbss. */
321 	make_ecoff_section_hdrs(&ep, esecs);
322 
323 	nsecs = ep.f.f_nscns;
324 
325 	if (needswap) {
326 		ep.f.f_magic	= bswap16(ep.f.f_magic);
327 		ep.f.f_nscns	= bswap16(ep.f.f_nscns);
328 		ep.f.f_timdat	= bswap32(ep.f.f_timdat);
329 		ep.f.f_symptr	= bswap32(ep.f.f_symptr);
330 		ep.f.f_nsyms	= bswap32(ep.f.f_nsyms);
331 		ep.f.f_opthdr	= bswap16(ep.f.f_opthdr);
332 		ep.f.f_flags	= bswap16(ep.f.f_flags);
333 		ep.a.magic	= bswap16(ep.a.magic);
334 		ep.a.vstamp	= bswap16(ep.a.vstamp);
335 		ep.a.tsize	= bswap32(ep.a.tsize);
336 		ep.a.dsize	= bswap32(ep.a.dsize);
337 		ep.a.bsize	= bswap32(ep.a.bsize);
338 		ep.a.entry	= bswap32(ep.a.entry);
339 		ep.a.text_start	= bswap32(ep.a.text_start);
340 		ep.a.data_start	= bswap32(ep.a.data_start);
341 		ep.a.bss_start	= bswap32(ep.a.bss_start);
342 		ep.a.gprmask	= bswap32(ep.a.gprmask);
343 		bswap32_region((int32_t*)ep.a.cprmask, sizeof(ep.a.cprmask));
344 		ep.a.gp_value	= bswap32(ep.a.gp_value);
345 		for (i = 0; i < sizeof(esecs) / sizeof(esecs[0]); i++) {
346 			esecs[i].s_paddr	= bswap32(esecs[i].s_paddr);
347 			esecs[i].s_vaddr	= bswap32(esecs[i].s_vaddr);
348 			esecs[i].s_size 	= bswap32(esecs[i].s_size);
349 			esecs[i].s_scnptr	= bswap32(esecs[i].s_scnptr);
350 			esecs[i].s_relptr	= bswap32(esecs[i].s_relptr);
351 			esecs[i].s_lnnoptr	= bswap32(esecs[i].s_lnnoptr);
352 			esecs[i].s_nreloc	= bswap16(esecs[i].s_nreloc);
353 			esecs[i].s_nlnno	= bswap16(esecs[i].s_nlnno);
354 			esecs[i].s_flags	= bswap32(esecs[i].s_flags);
355 		}
356 	}
357 
358 	/* Make the output file... */
359 	if ((outfile = open(argv[2], O_WRONLY | O_CREAT, 0777)) < 0)
360 		err(1, "Unable to create %s", argv[2]);
361 
362 	/* Truncate file... */
363 	if (ftruncate(outfile, 0)) {
364 		warn("ftruncate %s", argv[2]);
365 	}
366 	/* Write the headers... */
367 	safewrite(outfile, &ep.f, sizeof(ep.f), "ep.f: write");
368 	if (debug)
369 		fprintf(stderr, "wrote %zu byte file header.\n", sizeof(ep.f));
370 
371 	safewrite(outfile, &ep.a, sizeof(ep.a), "ep.a: write");
372 	if (debug)
373 		fprintf(stderr, "wrote %zu byte a.out header.\n", sizeof(ep.a));
374 
375 	safewrite(outfile, &esecs, sizeof(esecs[0]) * nsecs, "esecs: write");
376 	if (debug)
377 		fprintf(stderr, "wrote %zu bytes of section headers.\n",
378 		    sizeof(esecs[0]) * nsecs);
379 
380 
381 	pad = ((sizeof ep.f + sizeof ep.a + sizeof esecs) & 15);
382 	if (pad) {
383 		pad = 16 - pad;
384 		pad16(outfile, pad, "ipad: write");
385 		if (debug)
386 			fprintf(stderr, "wrote %d byte pad.\n", pad);
387 	}
388 	/* Copy the loadable sections.   Zero-fill any gaps less than 64k;
389 	 * complain about any zero-filling, and die if we're asked to
390 	 * zero-fill more than 64k. */
391 	for (i = 0; i < ex.e_phnum; i++) {
392 		/* Unprocessable sections were handled above, so just verify
393 		 * that the section can be loaded before copying. */
394 		if (ph[i].p_type == PT_LOAD && ph[i].p_filesz) {
395 			if (cur_vma != ph[i].p_vaddr) {
396 				unsigned long gap = ph[i].p_vaddr - cur_vma;
397 				char    obuf[1024];
398 				if (gap > 65536)
399 					errx(1, "Intersegment gap (%ld bytes) "
400 					    "too large", gap);
401 				if (debug)
402 					fprintf(stderr, "Warning: %ld byte "
403 					    "intersegment gap.\n", gap);
404 				memset(obuf, 0, sizeof obuf);
405 				while (gap) {
406 					int count = write(outfile, obuf,
407 					    (gap > sizeof obuf
408 					    ? sizeof obuf : gap));
409 					if (count < 0)
410 						err(1, "Error writing gap");
411 					gap -= count;
412 				}
413 			}
414 			if (debug)
415 				fprintf(stderr, "writing %d bytes...\n",
416 				    ph[i].p_filesz);
417 			copy(outfile, infile, ph[i].p_offset, ph[i].p_filesz);
418 			cur_vma = ph[i].p_vaddr + ph[i].p_filesz;
419 		}
420 	}
421 
422 
423 	if (debug)
424 		fprintf(stderr, "writing syms at offset 0x%lx\n",
425 		    (u_long) ep.f.f_symptr + sizeof(symhdr));
426 
427 	/* Copy and translate the symbol table... */
428 	elf_symbol_table_to_ecoff(outfile, infile, &ep,
429 	    sh[symtabix].sh_offset, sh[symtabix].sh_size,
430 	    sh[strtabix].sh_offset, sh[strtabix].sh_size);
431 
432 	/*
433          * Write a page of padding for boot PROMS that read entire pages.
434          * Without this, they may attempt to read past the end of the
435          * data section, incur an error, and refuse to boot.
436          */
437 	{
438 		char    obuf[4096];
439 		memset(obuf, 0, sizeof obuf);
440 		if (write(outfile, obuf, sizeof(obuf)) != sizeof(obuf))
441 			err(1, "Error writing PROM padding");
442 	}
443 
444 	/* Looks like we won... */
445 	return 0;
446 }
447 
448 static void
449 copy(int out, int in, off_t offset, off_t size)
450 {
451 	char    ibuf[4096];
452 	size_t  remaining, cur, count;
453 
454 	/* Go to the start of the ELF symbol table... */
455 	if (lseek(in, offset, SEEK_SET) < 0)
456 		err(1, "copy: lseek");
457 	remaining = size;
458 	while (remaining) {
459 		cur = remaining;
460 		if (cur > sizeof ibuf)
461 			cur = sizeof ibuf;
462 		remaining -= cur;
463 		if ((count = read(in, ibuf, cur)) != cur)
464 			err(1, "copy: short read");
465 		safewrite(out, ibuf, cur, "copy: write");
466 	}
467 }
468 
469 /* Combine two segments, which must be contiguous.   If pad is true, it's
470    okay for there to be padding between. */
471 static void
472 combine(struct sect *base, struct sect *new, int pad)
473 {
474 
475 	if (base->len == 0)
476 		*base = *new;
477 	else
478 		if (new->len) {
479 			if (base->vaddr + base->len != new->vaddr) {
480 				if (pad)
481 					base->len = new->vaddr - base->vaddr;
482 				else
483 					errx(1, "Non-contiguous data can't be "
484 					    "converted");
485 			}
486 			base->len += new->len;
487 		}
488 }
489 
490 static int
491 phcmp(Elf32_Phdr *h1, Elf32_Phdr *h2)
492 {
493 
494 	if (h1->p_vaddr > h2->p_vaddr)
495 		return 1;
496 	else
497 		if (h1->p_vaddr < h2->p_vaddr)
498 			return -1;
499 		else
500 			return 0;
501 }
502 
503 static char *
504 saveRead(int file, off_t offset, off_t len, const char *name)
505 {
506 	char   *tmp;
507 	int     count;
508 	off_t   off;
509 
510 	if ((off = lseek(file, offset, SEEK_SET)) < 0)
511 		err(1, "%s: fseek", name);
512 	if ((tmp = malloc(len)) == NULL)
513 		err(1, "%s: Can't allocate %ld bytes", name, (long) len);
514 	count = read(file, tmp, len);
515 	if (count != len)
516 		err(1, "%s: short read", name);
517 	return tmp;
518 }
519 
520 static void
521 safewrite(int outfile, const void *buf, off_t len, const char *msg)
522 {
523 	ssize_t     written;
524 
525 	written = write(outfile, buf, len);
526 	if (written != len)
527 		err(1, "%s", msg);
528 }
529 
530 
531 /*
532  * Output only three ECOFF sections, corresponding to ELF psecs
533  * for text, data, and bss.
534  */
535 static int
536 make_ecoff_section_hdrs(struct ecoff_exechdr *ep, struct ecoff_scnhdr *esecs)
537 {
538 
539 	ep->f.f_nscns = 6;	/* XXX */
540 
541 	strcpy(esecs[0].s_name, ".text");
542 	strcpy(esecs[1].s_name, ".data");
543 	strcpy(esecs[2].s_name, ".bss");
544 
545 	esecs[0].s_paddr = esecs[0].s_vaddr = ep->a.text_start;
546 	esecs[1].s_paddr = esecs[1].s_vaddr = ep->a.data_start;
547 	esecs[2].s_paddr = esecs[2].s_vaddr = ep->a.bss_start;
548 	esecs[0].s_size = ep->a.tsize;
549 	esecs[1].s_size = ep->a.dsize;
550 	esecs[2].s_size = ep->a.bsize;
551 
552 	esecs[0].s_scnptr = ECOFF_TXTOFF(ep);
553 	esecs[1].s_scnptr = ECOFF_DATOFF(ep);
554 #if 0
555 	esecs[2].s_scnptr = esecs[1].s_scnptr +
556 	    ECOFF_ROUND(esecs[1].s_size, ECOFF_SEGMENT_ALIGNMENT(ep));
557 #endif
558 
559 	esecs[0].s_relptr = esecs[1].s_relptr = esecs[2].s_relptr = 0;
560 	esecs[0].s_lnnoptr = esecs[1].s_lnnoptr = esecs[2].s_lnnoptr = 0;
561 	esecs[0].s_nreloc = esecs[1].s_nreloc = esecs[2].s_nreloc = 0;
562 	esecs[0].s_nlnno = esecs[1].s_nlnno = esecs[2].s_nlnno = 0;
563 
564 	esecs[1].s_flags = 0x100;	/* ECOFF rdata */
565 	esecs[3].s_flags = 0x200;	/* ECOFF sdata */
566 	esecs[4].s_flags = 0x400;	/* ECOFF sbss */
567 
568 	/*
569 	 * Set the symbol-table offset  to point at the end of any
570 	 * sections we loaded above, so later code can use it to write
571 	 * symbol table info..
572 	 */
573 	ep->f.f_symptr = esecs[1].s_scnptr + esecs[1].s_size;
574 	return (ep->f.f_nscns);
575 }
576 
577 
578 /*
579  * Write the ECOFF symbol header.
580  * Guess at how big the symbol table will be.
581  * Mark all symbols as EXTERN (for now).
582  */
583 static void
584 write_ecoff_symhdr(int out, struct ecoff_exechdr *ep,
585     struct ecoff_symhdr *symhdrp, long nesyms,
586     long extsymoff, long extstroff, long strsize)
587 {
588 
589 	if (debug)
590 		fprintf(stderr,
591 		    "writing symhdr for %ld entries at offset 0x%lx\n",
592 		    nesyms, (u_long) ep->f.f_symptr);
593 
594 	ep->f.f_nsyms = sizeof(struct ecoff_symhdr);
595 
596 	memset(symhdrp, 0, sizeof(*symhdrp));
597 	symhdrp->esymMax = nesyms;
598 	symhdrp->magic = 0x7009;/* XXX */
599 	symhdrp->cbExtOffset = extsymoff;
600 	symhdrp->cbSsExtOffset = extstroff;
601 
602 	symhdrp->issExtMax = strsize;
603 	if (debug)
604 		fprintf(stderr,
605 		    "ECOFF symhdr: symhdr %zx, strsize %lx, symsize %lx\n",
606 		    sizeof(*symhdrp), strsize,
607 		    (nesyms * sizeof(struct ecoff_extsym)));
608 
609 	if (needswap) {
610 		bswap32_region(&symhdrp->ilineMax,
611 		    sizeof(*symhdrp) -  sizeof(symhdrp->magic) -
612 		    sizeof(symhdrp->ilineMax));
613 		symhdrp->magic = bswap16(symhdrp->magic);
614 		symhdrp->ilineMax = bswap16(symhdrp->ilineMax);
615 	}
616 
617 	safewrite(out, symhdrp, sizeof(*symhdrp),
618 	    "writing symbol header");
619 }
620 
621 
622 static void
623 elf_read_syms(struct elf_syms *elfsymsp, int in, off_t symoff, off_t symsize,
624     off_t stroff, off_t strsize)
625 {
626 	register int nsyms;
627 	int i;
628 	nsyms = symsize / sizeof(Elf32_Sym);
629 
630 	/* Suck in the ELF symbol list... */
631 	elfsymsp->elf_syms = (Elf32_Sym *)
632 	    saveRead(in, symoff, nsyms * sizeof(Elf32_Sym),
633 	    "ELF symboltable");
634 	elfsymsp->nsymbols = nsyms;
635 	if (needswap) {
636 		for (i = 0; i < nsyms; i++) {
637 			Elf32_Sym *s = &elfsymsp->elf_syms[i];
638 			s->st_name	= bswap32(s->st_name);
639 			s->st_value	= bswap32(s->st_value);
640 			s->st_size	= bswap32(s->st_size);
641 			s->st_shndx	= bswap16(s->st_shndx);
642 		}
643 	}
644 
645 	/* Suck in the ELF string table... */
646 	elfsymsp->stringtab = (char *)
647 	    saveRead(in, stroff, strsize, "ELF string table");
648 	elfsymsp->stringsize = strsize;
649 }
650 
651 
652 static void
653 elf_symbol_table_to_ecoff(int out, int in, struct ecoff_exechdr *ep,
654     off_t symoff, off_t symsize, off_t stroff, off_t strsize)
655 {
656 
657 	struct elf_syms elfsymtab;
658 	struct ecoff_syms ecoffsymtab;
659 	register u_long ecoff_symhdr_off, symtaboff, stringtaboff;
660 	register u_long nextoff, symtabsize, ecoff_strsize;
661 	int     nsyms, i;
662 	struct ecoff_symhdr symhdr;
663 	int     padding;
664 
665 	/* Read in the ELF symbols. */
666 	elf_read_syms(&elfsymtab, in, symoff, symsize, stroff, strsize);
667 
668 	/* Approximate translation to ECOFF. */
669 	translate_syms(&elfsymtab, &ecoffsymtab);
670 	nsyms = ecoffsymtab.nsymbols;
671 
672 	/* Compute output ECOFF symbol- and string-table offsets. */
673 	ecoff_symhdr_off = ep->f.f_symptr;
674 
675 	nextoff = ecoff_symhdr_off + sizeof(struct ecoff_symhdr);
676 	stringtaboff = nextoff;
677 	ecoff_strsize = ECOFF_ROUND(ecoffsymtab.stringsize,
678 	    (ECOFF_SEGMENT_ALIGNMENT(ep)));
679 
680 
681 	nextoff = stringtaboff + ecoff_strsize;
682 	symtaboff = nextoff;
683 	symtabsize = nsyms * sizeof(struct ecoff_extsym);
684 	symtabsize = ECOFF_ROUND(symtabsize, ECOFF_SEGMENT_ALIGNMENT(ep));
685 
686 	/* Write out the symbol header ... */
687 	write_ecoff_symhdr(out, ep, &symhdr, nsyms, symtaboff,
688 	    stringtaboff, ecoffsymtab.stringsize);
689 
690 	/* Write out the string table... */
691 	padding = ecoff_strsize - ecoffsymtab.stringsize;
692 	safewrite(out, ecoffsymtab.stringtab, ecoffsymtab.stringsize,
693 	    "string table: write");
694 	if (padding)
695 		pad16(out, padding, "string table: padding");
696 
697 
698 	/* Write out the symbol table... */
699 	padding = symtabsize - (nsyms * sizeof(struct ecoff_extsym));
700 
701 	for (i = 0; i < nsyms; i++) {
702 		struct ecoff_extsym *es = &ecoffsymtab.ecoff_syms[i];
703 		es->es_flags	= bswap16(es->es_flags);
704 		es->es_ifd	= bswap16(es->es_ifd);
705 		bswap32_region(&es->es_strindex,
706 		    sizeof(*es) - sizeof(es->es_flags) - sizeof(es->es_ifd));
707 	}
708 	safewrite(out, ecoffsymtab.ecoff_syms,
709 	    nsyms * sizeof(struct ecoff_extsym),
710 	    "symbol table: write");
711 	if (padding)
712 		pad16(out, padding, "symbols: padding");
713 }
714 
715 
716 
717 /*
718  * In-memory translation of ELF symbosl to ECOFF.
719  */
720 static void
721 translate_syms(struct elf_syms *elfp, struct ecoff_syms *ecoffp)
722 {
723 
724 	int     i;
725 	char   *oldstringbase;
726 	char   *newstrings, *nsp;
727 
728 	int     nsyms, idx;
729 
730 	nsyms = elfp->nsymbols;
731 	oldstringbase = elfp->stringtab;
732 
733 	/* Allocate space for corresponding ECOFF symbols. */
734 	memset(ecoffp, 0, sizeof(*ecoffp));
735 
736 	ecoffp->nsymbols = 0;
737 	ecoffp->ecoff_syms = malloc(sizeof(struct ecoff_extsym) * nsyms);
738 
739 	/* we are going to be no bigger than the ELF symbol table. */
740 	ecoffp->stringsize = elfp->stringsize;
741 	ecoffp->stringtab = malloc(elfp->stringsize);
742 
743 	newstrings = (char *) ecoffp->stringtab;
744 	nsp = (char *) ecoffp->stringtab;
745 	if (newstrings == NULL)
746 		errx(1, "No memory for new string table");
747 	/* Copy and translate  symbols... */
748 	idx = 0;
749 	for (i = 0; i < nsyms; i++) {
750 		int     binding;
751 
752 		binding = ELF32_ST_BIND((elfp->elf_syms[i].st_info));
753 
754 		/* skip strange symbols */
755 		if (binding == 0) {
756 			continue;
757 		}
758 		/* Copy the symbol into the new table */
759 		strcpy(nsp, oldstringbase + elfp->elf_syms[i].st_name);
760 		ecoffp->ecoff_syms[idx].es_strindex = nsp - newstrings;
761 		nsp += strlen(nsp) + 1;
762 
763 		/* translate symbol types to ECOFF XXX */
764 		ecoffp->ecoff_syms[idx].es_type = 1;
765 		ecoffp->ecoff_syms[idx].es_class = 5;
766 
767 		/* Symbol values in executables should be compatible. */
768 		ecoffp->ecoff_syms[idx].es_value = elfp->elf_syms[i].st_value;
769 		ecoffp->ecoff_syms[idx].es_symauxindex = 0xfffff;
770 
771 		idx++;
772 	}
773 
774 	ecoffp->nsymbols = idx;
775 	ecoffp->stringsize = nsp - newstrings;
776 }
777 /*
778  * pad to a 16-byte boundary
779  */
780 static void
781 pad16(int fd, int size, const char *msg)
782 {
783 
784 	safewrite(fd, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0", size, msg);
785 }
786 
787 /* swap a 32bit region */
788 static void
789 bswap32_region(int32_t* p, int len)
790 {
791 	size_t i;
792 
793 	for (i = 0; i < len / sizeof(int32_t); i++, p++)
794 		*p = bswap32(*p);
795 }
796