xref: /plan9-contrib/sys/src/libmach/executable.c (revision 4d44ba9b9ee4246ddbd96c7fcaf0918ab92ab35a)
1 #include	<u.h>
2 #include	<libc.h>
3 #include	<bio.h>
4 #include	<bootexec.h>
5 #include	<mach.h>
6 #include	"elf.h"
7 
8 /*
9  *	All a.out header types.  The dummy entry allows canonical
10  *	processing of the union as a sequence of longs
11  */
12 
13 typedef struct {
14 	union{
15 		Exec;			/* in a.out.h */
16 		Ehdr;			/* in elf.h */
17 		struct mipsexec;
18 		struct mips4kexec;
19 		struct sparcexec;
20 		struct nextexec;
21 	} e;
22 	long dummy;		/* padding to ensure extra long */
23 } ExecHdr;
24 
25 static	int	nextboot(int, Fhdr*, ExecHdr*);
26 static	int	sparcboot(int, Fhdr*, ExecHdr*);
27 static	int	mipsboot(int, Fhdr*, ExecHdr*);
28 static	int	mips4kboot(int, Fhdr*, ExecHdr*);
29 static	int	common(int, Fhdr*, ExecHdr*);
30 static	int	adotout(int, Fhdr*, ExecHdr*);
31 static	int	elfdotout(int, Fhdr*, ExecHdr*);
32 static	int	armdotout(int, Fhdr*, ExecHdr*);
33 static	int	alphadotout(int, Fhdr*, ExecHdr*);
34 static	void	setsym(Fhdr*, long, long, long, long);
35 static	void	setdata(Fhdr*, long, long, long, long);
36 static	void	settext(Fhdr*, long, long, long, long);
37 static	void	hswal(long*, int, long(*)(long));
38 static	long	noswal(long);
39 static	long	_round(long, long);
40 
41 /*
42  *	definition of per-executable file type structures
43  */
44 
45 typedef struct Exectable{
46 	long	magic;			/* big-endian magic number of file */
47 	char	*name;			/* executable identifier */
48 	char	*dlmname;		/* dynamically loadable module identifier */
49 	int	type;			/* Internal code */
50 	Mach	*mach;			/* Per-machine data */
51 	ulong	hsize;			/* header size */
52 	long	(*swal)(long);		/* beswal or leswal */
53 	int	(*hparse)(int, Fhdr*, ExecHdr*);
54 } ExecTable;
55 
56 extern	Mach	mmips;
57 extern	Mach	mmips2le;
58 extern	Mach	mmips2be;
59 extern	Mach	msparc;
60 extern	Mach	msparc64;
61 extern	Mach	m68020;
62 extern	Mach	mi386;
63 extern	Mach	mamd64;
64 extern	Mach	marm;
65 extern	Mach	mpower;
66 extern	Mach	malpha;
67 
68 ExecTable exectab[] =
69 {
70 	{ V_MAGIC,			/* Mips v.out */
71 		"mips plan 9 executable",
72 		"mips plan 9 dlm",
73 		FMIPS,
74 		&mmips,
75 		sizeof(Exec),
76 		beswal,
77 		adotout },
78 	{ M_MAGIC,			/* Mips 4.out */
79 		"mips 4k plan 9 executable BE",
80 		"mips 4k plan 9 dlm BE",
81 		FMIPS2BE,
82 		&mmips2be,
83 		sizeof(Exec),
84 		beswal,
85 		adotout },
86 	{ N_MAGIC,			/* Mips 0.out */
87 		"mips 4k plan 9 executable LE",
88 		"mips 4k plan 9 dlm LE",
89 		FMIPS2LE,
90 		&mmips2le,
91 		sizeof(Exec),
92 		beswal,
93 		adotout },
94 	{ 0x160<<16,			/* Mips boot image */
95 		"mips plan 9 boot image",
96 		nil,
97 		FMIPSB,
98 		&mmips,
99 		sizeof(struct mipsexec),
100 		beswal,
101 		mipsboot },
102 	{ (0x160<<16)|3,		/* Mips boot image */
103 		"mips 4k plan 9 boot image",
104 		nil,
105 		FMIPSB,
106 		&mmips2be,
107 		sizeof(struct mips4kexec),
108 		beswal,
109 		mips4kboot },
110 	{ K_MAGIC,			/* Sparc k.out */
111 		"sparc plan 9 executable",
112 		"sparc plan 9 dlm",
113 		FSPARC,
114 		&msparc,
115 		sizeof(Exec),
116 		beswal,
117 		adotout },
118 	{ 0x01030107, 			/* Sparc boot image */
119 		"sparc plan 9 boot image",
120 		nil,
121 		FSPARCB,
122 		&msparc,
123 		sizeof(struct sparcexec),
124 		beswal,
125 		sparcboot },
126 	{ U_MAGIC,			/* Sparc64 u.out */
127 		"sparc64 plan 9 executable",
128 		"sparc64 plan 9 dlm",
129 		FSPARC64,
130 		&msparc64,
131 		sizeof(Exec),
132 		beswal,
133 		adotout },
134 	{ A_MAGIC,			/* 68020 2.out & boot image */
135 		"68020 plan 9 executable",
136 		"68020 plan 9 dlm",
137 		F68020,
138 		&m68020,
139 		sizeof(Exec),
140 		beswal,
141 		common },
142 	{ 0xFEEDFACE,			/* Next boot image */
143 		"next plan 9 boot image",
144 		nil,
145 		FNEXTB,
146 		&m68020,
147 		sizeof(struct nextexec),
148 		beswal,
149 		nextboot },
150 	{ I_MAGIC,			/* I386 8.out & boot image */
151 		"386 plan 9 executable",
152 		"386 plan 9 dlm",
153 		FI386,
154 		&mi386,
155 		sizeof(Exec),
156 		beswal,
157 		common },
158 	{ S_MAGIC,			/* amd64 6.out & boot image */
159 		"amd64 plan 9 executable",
160 		"amd64 plan 9 dlm",
161 		FAMD64,
162 		&mamd64,
163 		sizeof(Exec),
164 		beswal,
165 		common },
166 	{ Q_MAGIC,			/* PowerPC q.out & boot image */
167 		"power plan 9 executable",
168 		"power plan 9 dlm",
169 		FPOWER,
170 		&mpower,
171 		sizeof(Exec),
172 		beswal,
173 		common },
174 	{ ELF_MAG,			/* any elf32 */
175 		"elf executable",
176 		nil,
177 		FNONE,
178 		&mi386,
179 		sizeof(Ehdr),
180 		noswal,
181 		elfdotout },
182 	{ E_MAGIC,			/* Arm 5.out */
183 		"arm plan 9 executable",
184 		"arm plan 9 dlm",
185 		FARM,
186 		&marm,
187 		sizeof(Exec),
188 		beswal,
189 		common },
190 	{ (143<<16)|0413,		/* (Free|Net)BSD Arm */
191 		"arm *bsd executable",
192 		nil,
193 		FARM,
194 		&marm,
195 		sizeof(Exec),
196 		leswal,
197 		armdotout },
198 	{ L_MAGIC,			/* alpha 7.out */
199 		"alpha plan 9 executable",
200 		"alpha plan 9 dlm",
201 		FALPHA,
202 		&malpha,
203 		sizeof(Exec),
204 		beswal,
205 		common },
206 	{ 0x0700e0c3,			/* alpha boot image */
207 		"alpha plan 9 boot image",
208 		nil,
209 		FALPHAB,
210 		&malpha,
211 		sizeof(Exec),
212 		beswal,
213 		alphadotout },
214 	{ 0 },
215 };
216 
217 Mach	*mach = &mi386;			/* Global current machine table */
218 
219 static ExecTable*
220 couldbe4k(ExecTable *mp)
221 {
222 	Dir *d;
223 	ExecTable *f;
224 
225 	if((d=dirstat("/proc/1/regs")) == nil)
226 		return mp;
227 	if(d->length < 32*8){		/* R3000 */
228 		free(d);
229 		return mp;
230 	}
231 	free(d);
232 	for (f = exectab; f->magic; f++)
233 		if(f->magic == M_MAGIC) {
234 			f->name = "mips plan 9 executable on mips2 kernel";
235 			return f;
236 		}
237 	return mp;
238 }
239 
240 int
241 crackhdr(int fd, Fhdr *fp)
242 {
243 	ExecTable *mp;
244 	ExecHdr d;
245 	int nb, magic, ret;
246 
247 	fp->type = FNONE;
248 	nb = read(fd, (char *)&d.e, sizeof(d.e));
249 	if (nb <= 0)
250 		return 0;
251 
252 	ret = 0;
253 	fp->magic = magic = beswal(d.e.magic);		/* big-endian */
254 	for (mp = exectab; mp->magic; mp++) {
255 		if (nb < mp->hsize)
256 			continue;
257 		if (mp->magic == (magic & ~DYN_MAGIC)) {
258 			if(mp->magic == V_MAGIC)
259 				mp = couldbe4k(mp);
260 
261 			hswal((long *) &d, sizeof(d.e)/sizeof(long), mp->swal);
262 			fp->type = mp->type;
263 			if ((magic & DYN_MAGIC) && mp->dlmname != nil)
264 				fp->name = mp->dlmname;
265 			else
266 				fp->name = mp->name;
267 			fp->hdrsz = mp->hsize;		/* zero on bootables */
268 			mach = mp->mach;
269 			ret  = mp->hparse(fd, fp, &d);
270 			seek(fd, mp->hsize, 0);		/* seek to end of header */
271 			break;
272 		}
273 	}
274 	if(mp->magic == 0)
275 		werrstr("unknown header type");
276 	return ret;
277 }
278 /*
279  * Convert header to canonical form
280  */
281 static void
282 hswal(long *lp, int n, long (*swap) (long))
283 {
284 	while (n--) {
285 		*lp = (*swap) (*lp);
286 		lp++;
287 	}
288 }
289 /*
290  * noop
291  */
292 static long
293 noswal(long x)
294 {
295 	return x;
296 }
297 /*
298  *	Crack a normal a.out-type header
299  */
300 static int
301 adotout(int fd, Fhdr *fp, ExecHdr *hp)
302 {
303 	long pgsize;
304 
305 	USED(fd);
306 	pgsize = mach->pgsize;
307 	settext(fp, hp->e.entry, pgsize+sizeof(Exec),
308 			hp->e.text, sizeof(Exec));
309 	setdata(fp, _round(pgsize+fp->txtsz+sizeof(Exec), pgsize),
310 		hp->e.data, fp->txtsz+sizeof(Exec), hp->e.bss);
311 	setsym(fp, hp->e.syms, hp->e.spsz, hp->e.pcsz, fp->datoff+fp->datsz);
312 	return 1;
313 }
314 
315 /*
316  *	68020 2.out and 68020 bootable images
317  *	386I 8.out and 386I bootable images
318  *	alpha plan9-style bootable images for axp "headerless" boot
319  *
320  */
321 static int
322 common(int fd, Fhdr *fp, ExecHdr *hp)
323 {
324 	long kbase;
325 
326 	adotout(fd, fp, hp);
327 	if(hp->e.magic & DYN_MAGIC) {
328 		fp->txtaddr = 0;
329 		fp->dataddr = fp->txtsz;
330 		return 1;
331 	}
332 	kbase = mach->kbase;
333 	if ((fp->entry & kbase) == kbase) {		/* Boot image */
334 		switch(fp->type) {
335 		case F68020:
336 			fp->type = F68020B;
337 			fp->name = "68020 plan 9 boot image";
338 			fp->hdrsz = 0;		/* header stripped */
339 			break;
340 		case FI386:
341 			fp->type = FI386B;
342 			fp->txtaddr = sizeof(Exec);
343 			fp->name = "386 plan 9 boot image";
344 			fp->hdrsz = 0;		/* header stripped */
345 			fp->dataddr = fp->txtaddr+fp->txtsz;
346 			break;
347 		case FARM:
348 			fp->txtaddr = kbase+0x8010;
349 			fp->name = "ARM plan 9 boot image";
350 			fp->hdrsz = 0;		/* header stripped */
351 			fp->dataddr = fp->txtaddr+fp->txtsz;
352 			return 1;
353 		case FALPHA:
354 			fp->type = FALPHAB;
355 			fp->txtaddr = fp->entry;
356 			fp->name = "alpha plan 9 boot image?";
357 			fp->hdrsz = 0;		/* header stripped */
358 			fp->dataddr = fp->txtaddr+fp->txtsz;
359 			break;
360 		case FPOWER:
361 			fp->type = FPOWERB;
362 			fp->txtaddr = fp->entry;
363 			fp->name = "power plan 9 boot image";
364 			fp->hdrsz = 0;		/* header stripped */
365 			fp->dataddr = fp->txtaddr+fp->txtsz;
366 			break;
367 		default:
368 			break;
369 		}
370 		fp->txtaddr |= kbase;
371 		fp->entry |= kbase;
372 		fp->dataddr |= kbase;
373 	}
374 	return 1;
375 }
376 
377 /*
378  *	mips bootable image.
379  */
380 static int
381 mipsboot(int fd, Fhdr *fp, ExecHdr *hp)
382 {
383 	USED(fd);
384 	switch(hp->e.amagic) {
385 	default:
386 	case 0407:	/* some kind of mips */
387 		fp->type = FMIPSB;
388 		settext(fp, hp->e.mentry, hp->e.text_start, hp->e.tsize,
389 					sizeof(struct mipsexec)+4);
390 		setdata(fp, hp->e.data_start, hp->e.dsize,
391 				fp->txtoff+hp->e.tsize, hp->e.bsize);
392 		break;
393 	case 0413:	/* some kind of mips */
394 		fp->type = FMIPSB;
395 		settext(fp, hp->e.mentry, hp->e.text_start, hp->e.tsize, 0);
396 		setdata(fp, hp->e.data_start, hp->e.dsize, hp->e.tsize,
397 					hp->e.bsize);
398 		break;
399 	}
400 	setsym(fp, hp->e.nsyms, 0, hp->e.pcsize, hp->e.symptr);
401 	fp->hdrsz = 0;		/* header stripped */
402 	return 1;
403 }
404 
405 /*
406  *	mips4k bootable image.
407  */
408 static int
409 mips4kboot(int fd, Fhdr *fp, ExecHdr *hp)
410 {
411 	USED(fd);
412 	switch(hp->e.h.amagic) {
413 	default:
414 	case 0407:	/* some kind of mips */
415 		fp->type = FMIPSB;
416 		settext(fp, hp->e.h.mentry, hp->e.h.text_start, hp->e.h.tsize,
417 					sizeof(struct mips4kexec));
418 		setdata(fp, hp->e.h.data_start, hp->e.h.dsize,
419 				fp->txtoff+hp->e.h.tsize, hp->e.h.bsize);
420 		break;
421 	case 0413:	/* some kind of mips */
422 		fp->type = FMIPSB;
423 		settext(fp, hp->e.h.mentry, hp->e.h.text_start, hp->e.h.tsize, 0);
424 		setdata(fp, hp->e.h.data_start, hp->e.h.dsize, hp->e.h.tsize,
425 					hp->e.h.bsize);
426 		break;
427 	}
428 	setsym(fp, hp->e.h.nsyms, 0, hp->e.h.pcsize, hp->e.h.symptr);
429 	fp->hdrsz = 0;		/* header stripped */
430 	return 1;
431 }
432 
433 /*
434  *	sparc bootable image
435  */
436 static int
437 sparcboot(int fd, Fhdr *fp, ExecHdr *hp)
438 {
439 	USED(fd);
440 	fp->type = FSPARCB;
441 	settext(fp, hp->e.sentry, hp->e.sentry, hp->e.stext,
442 					sizeof(struct sparcexec));
443 	setdata(fp, hp->e.sentry+hp->e.stext, hp->e.sdata,
444 					fp->txtoff+hp->e.stext, hp->e.sbss);
445 	setsym(fp, hp->e.ssyms, 0, hp->e.sdrsize, fp->datoff+hp->e.sdata);
446 	fp->hdrsz = 0;		/* header stripped */
447 	return 1;
448 }
449 
450 /*
451  *	next bootable image
452  */
453 static int
454 nextboot(int fd, Fhdr *fp, ExecHdr *hp)
455 {
456 	USED(fd);
457 	fp->type = FNEXTB;
458 	settext(fp, hp->e.textc.vmaddr, hp->e.textc.vmaddr,
459 					hp->e.texts.size, hp->e.texts.offset);
460 	setdata(fp, hp->e.datac.vmaddr, hp->e.datas.size,
461 				hp->e.datas.offset, hp->e.bsss.size);
462 	setsym(fp, hp->e.symc.nsyms, hp->e.symc.spoff, hp->e.symc.pcoff,
463 					hp->e.symc.symoff);
464 	fp->hdrsz = 0;		/* header stripped */
465 	return 1;
466 }
467 
468 
469 /*
470  * Elf32 binaries.
471  */
472 static int
473 elfdotout(int fd, Fhdr *fp, ExecHdr *hp)
474 {
475 
476 	long (*swal)(long);
477 	ushort (*swab)(ushort);
478 	Ehdr *ep;
479 	Phdr *ph;
480 	int i, it, id, is, phsz;
481 
482 	/* bitswap the header according to the DATA format */
483 	ep = &hp->e;
484 	if(ep->ident[CLASS] != ELFCLASS32) {
485 		werrstr("bad ELF class - not 32 bit");
486 		return 0;
487 	}
488 	if(ep->ident[DATA] == ELFDATA2LSB) {
489 		swab = leswab;
490 		swal = leswal;
491 	} else if(ep->ident[DATA] == ELFDATA2MSB) {
492 		swab = beswab;
493 		swal = beswal;
494 	} else {
495 		werrstr("bad ELF encoding - not big or little endian");
496 		return 0;
497 	}
498 
499 	ep->type = swab(ep->type);
500 	ep->machine = swab(ep->machine);
501 	ep->version = swal(ep->version);
502 	ep->elfentry = swal(ep->elfentry);
503 	ep->phoff = swal(ep->phoff);
504 	ep->shoff = swal(ep->shoff);
505 	ep->flags = swal(ep->flags);
506 	ep->ehsize = swab(ep->ehsize);
507 	ep->phentsize = swab(ep->phentsize);
508 	ep->phnum = swab(ep->phnum);
509 	ep->shentsize = swab(ep->shentsize);
510 	ep->shnum = swab(ep->shnum);
511 	ep->shstrndx = swab(ep->shstrndx);
512 	if(ep->type != EXEC || ep->version != CURRENT)
513 		return 0;
514 
515 	/* we could definitely support a lot more machines here */
516 	fp->magic = ELF_MAG;
517 	fp->hdrsz = (ep->ehsize+ep->phnum*ep->phentsize+16)&~15;
518 	switch(ep->machine) {
519 	case I386:
520 		mach = &mi386;
521 		fp->type = FI386;
522 		break;
523 	case MIPS:
524 		mach = &mmips;
525 		fp->type = FMIPS;
526 		break;
527 	case SPARC64:
528 		mach = &msparc64;
529 		fp->type = FSPARC64;
530 		break;
531 	case POWER:
532 		mach = &mpower;
533 		fp->type = FPOWER;
534 		break;
535 	case AMD64:
536 		mach = &mamd64;
537 		fp->type = FAMD64;
538 		break;
539 	default:
540 		return 0;
541 	}
542 
543 	if(ep->phentsize != sizeof(Phdr)) {
544 		werrstr("bad ELF header size");
545 		return 0;
546 	}
547 	phsz = sizeof(Phdr)*ep->phnum;
548 	ph = malloc(phsz);
549 	if(!ph)
550 		return 0;
551 	seek(fd, ep->phoff, 0);
552 	if(read(fd, ph, phsz) < 0) {
553 		free(ph);
554 		return 0;
555 	}
556 	hswal((long*)ph, phsz/sizeof(long), swal);
557 
558 	/* find text, data and symbols and install them */
559 	it = id = is = -1;
560 	for(i = 0; i < ep->phnum; i++) {
561 		if(ph[i].type == LOAD
562 		&& (ph[i].flags & (R|X)) == (R|X) && it == -1)
563 			it = i;
564 		else if(ph[i].type == LOAD
565 		&& (ph[i].flags & (R|W)) == (R|W) && id == -1)
566 			id = i;
567 		else if(ph[i].type == NOPTYPE && is == -1)
568 			is = i;
569 	}
570 	if(it == -1 || id == -1) {
571 		/*
572 		 * The SPARC64 boot image is something of an ELF hack.
573 		 * Text+Data+BSS are represented by ph[0].  Symbols
574 		 * are represented by ph[1]:
575 		 *
576 		 *		filesz, memsz, vaddr, paddr, off
577 		 * ph[0] : txtsz+datsz, txtsz+datsz+bsssz, txtaddr-KZERO, datasize,  txtoff
578 		 * ph[1] : symsz, lcsz, 0, 0, symoff
579 		 */
580 		if(ep->machine == SPARC64 && ep->phnum == 2) {
581 			ulong txtaddr, txtsz, dataddr, bsssz;
582 
583 			txtaddr = ph[0].vaddr | 0x80000000;
584 			txtsz = ph[0].filesz - ph[0].paddr;
585 			dataddr = txtaddr + txtsz;
586 			bsssz = ph[0].memsz - ph[0].filesz;
587 			settext(fp, ep->elfentry | 0x80000000, txtaddr, txtsz, ph[0].offset);
588 			setdata(fp, dataddr, ph[0].paddr, ph[0].offset + txtsz, bsssz);
589 			setsym(fp, ph[1].filesz, 0, ph[1].memsz, ph[1].offset);
590 			free(ph);
591 			return 1;
592 		}
593 
594 		werrstr("No TEXT or DATA sections");
595 		free(ph);
596 		return 0;
597 	}
598 
599 	settext(fp, ep->elfentry, ph[it].vaddr, ph[it].memsz, ph[it].offset);
600 	setdata(fp, ph[id].vaddr, ph[id].filesz, ph[id].offset, ph[id].memsz - ph[id].filesz);
601 	if(is != -1)
602 		setsym(fp, ph[is].filesz, 0, ph[is].memsz, ph[is].offset);
603 	free(ph);
604 	return 1;
605 }
606 
607 /*
608  * alpha bootable
609  */
610 static int
611 alphadotout(int fd, Fhdr *fp, ExecHdr *hp)
612 {
613 	long kbase;
614 
615 	USED(fd);
616 	settext(fp, hp->e.entry, sizeof(Exec), hp->e.text, sizeof(Exec));
617 	setdata(fp, fp->txtsz+sizeof(Exec), hp->e.data, fp->txtsz+sizeof(Exec), hp->e.bss);
618 	setsym(fp, hp->e.syms, hp->e.spsz, hp->e.pcsz, fp->datoff+fp->datsz);
619 
620 	/*
621 	 * Boot images have some of bits <31:28> set:
622 	 *	0x80400000	kernel
623 	 *	0x20000000	secondary bootstrap
624 	 */
625 	kbase = 0xF0000000;
626 	if (fp->entry & kbase) {
627 		fp->txtaddr = fp->entry;
628 		fp->name = "alpha plan 9 boot image";
629 		fp->hdrsz = 0;		/* header stripped */
630 		fp->dataddr = fp->entry+fp->txtsz;
631 	}
632 	return 1;
633 }
634 
635 /*
636  * (Free|Net)BSD ARM header.
637  */
638 static int
639 armdotout(int fd, Fhdr *fp, ExecHdr *hp)
640 {
641 	long kbase;
642 
643 	USED(fd);
644 	settext(fp, hp->e.entry, sizeof(Exec), hp->e.text, sizeof(Exec));
645 	setdata(fp, fp->txtsz, hp->e.data, fp->txtsz, hp->e.bss);
646 	setsym(fp, hp->e.syms, hp->e.spsz, hp->e.pcsz, fp->datoff+fp->datsz);
647 
648 	kbase = 0xF0000000;
649 	if ((fp->entry & kbase) == kbase) {		/* Boot image */
650 		fp->txtaddr = kbase+sizeof(Exec);
651 		fp->name = "ARM *BSD boot image";
652 		fp->hdrsz = 0;		/* header stripped */
653 		fp->dataddr = kbase+fp->txtsz;
654 	}
655 	return 1;
656 }
657 
658 static void
659 settext(Fhdr *fp, long e, long a, long s, long off)
660 {
661 	fp->txtaddr = a;
662 	fp->entry = e;
663 	fp->txtsz = s;
664 	fp->txtoff = off;
665 }
666 static void
667 setdata(Fhdr *fp, long a, long s, long off, long bss)
668 {
669 	fp->dataddr = a;
670 	fp->datsz = s;
671 	fp->datoff = off;
672 	fp->bsssz = bss;
673 }
674 static void
675 setsym(Fhdr *fp, long sy, long sppc, long lnpc, long symoff)
676 {
677 	fp->symsz = sy;
678 	fp->symoff = symoff;
679 	fp->sppcsz = sppc;
680 	fp->sppcoff = fp->symoff+fp->symsz;
681 	fp->lnpcsz = lnpc;
682 	fp->lnpcoff = fp->sppcoff+fp->sppcsz;
683 }
684 
685 
686 static long
687 _round(long a, long b)
688 {
689 	long w;
690 
691 	w = (a/b)*b;
692 	if (a!=w)
693 		w += b;
694 	return(w);
695 }
696