xref: /titanic_41/usr/src/cmd/sgs/rtld/common/a.out.c (revision 4df55fde49134f9735f84011f23a767c75e393c7)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Object file dependent support for a.out format objects.
29  */
30 
31 #include	<a.out.h>		/* Explicitly override M_SEGSIZE */
32 #include	<machdep.h>		/*	used in M_SROUND */
33 
34 #include	<sys/types.h>
35 #include	<sys/procfs.h>
36 #include	<sys/mman.h>
37 #include	<fcntl.h>
38 #include	<unistd.h>
39 #include	<string.h>
40 #include	<limits.h>
41 #include	<stdio.h>
42 #include	<dlfcn.h>
43 #include	<errno.h>
44 #include	<debug.h>
45 #include	"_a.out.h"
46 #include	"cache_a.out.h"
47 #include	"msg.h"
48 #include	"_rtld.h"
49 
50 /*
51  * Default and secure dependency search paths.
52  */
53 static Spath_defn _aout_def_dirs[] = {
54 	{ MSG_ORIG(MSG_PTH_USR4LIB),		MSG_PTH_USR4LIB_SIZE },
55 	{ MSG_ORIG(MSG_PTH_USRLIB),		MSG_PTH_USRLIB_SIZE },
56 	{ MSG_ORIG(MSG_PTH_USRLCLIB),		MSG_PTH_USRLCLIB_SIZE },
57 	{ 0, 0 }
58 };
59 
60 static Spath_defn _aout_sec_dirs[] = {
61 	{ MSG_ORIG(MSG_PTH_LIBSE),		MSG_PTH_LIBSE_SIZE },
62 	{ 0, 0 }
63 };
64 
65 Alist	*aout_def_dirs = NULL;
66 Alist	*aout_sec_dirs = NULL;
67 
68 /*
69  * Defines for local functions.
70  */
71 static void	aout_dladdr(ulong_t, Rt_map *, Dl_info *, void **, int);
72 static Sym	*aout_dlsym_handle(Grp_hdl *, Slookup *, Rt_map **, uint_t *,
73 		    int *l);
74 static Addr	aout_entry_point(void);
75 static Sym	*aout_find_sym(Slookup *, Rt_map **, uint_t *, int *);
76 static int	aout_fix_name(const char *, Rt_map *, Alist **, Aliste, uint_t);
77 static Alist	**aout_get_def_dirs(void);
78 static Alist	**aout_get_sec_dirs(void);
79 static char	*aout_get_so(const char *, const char *, size_t, size_t);
80 extern Sym	*aout_lookup_sym(Slookup *, Rt_map **, uint_t *, int *);
81 static int	aout_needed(Lm_list *, Aliste, Rt_map *, int *);
82 
83 /*
84  * Functions and data accessed through indirect pointers.
85  */
86 Fct aout_fct = {
87 	aout_verify,
88 	aout_new_lmp,
89 	aout_entry_point,
90 	aout_needed,
91 	aout_lookup_sym,
92 	aout_reloc,
93 	aout_get_def_dirs,
94 	aout_get_sec_dirs,
95 	aout_fix_name,
96 	aout_get_so,
97 	aout_dladdr,
98 	aout_dlsym_handle
99 };
100 
101 /*
102  * Default and secure dependency search paths.
103  */
104 static Alist **
105 aout_get_def_dirs()
106 {
107 	if (aout_def_dirs == NULL)
108 		set_dirs(&aout_def_dirs, _aout_def_dirs, LA_SER_DEFAULT);
109 	return (&aout_def_dirs);
110 }
111 
112 static Alist **
113 aout_get_sec_dirs()
114 {
115 	if (aout_sec_dirs == NULL)
116 		set_dirs(&aout_sec_dirs, _aout_sec_dirs, LA_SER_SECURE);
117 	return (&aout_sec_dirs);
118 }
119 
120 /*
121  * In 4.x, a needed file or a dlopened file that was a simple file name implied
122  * that the file be found in the present working directory.  To simulate this
123  * lookup within the ELF rules it is necessary to add a preceding `./' to the
124  * filename.
125  */
126 /* ARGSUSED4 */
127 static int
128 aout_fix_name(const char *oname, Rt_map *clmp, Alist **alpp, Aliste alni,
129     uint_t orig)
130 {
131 	size_t		len;
132 	Pdesc		*pdp;
133 	const char	*nname;
134 
135 	/*
136 	 * Check for slash in name, if none, prepend "./", otherwise just
137 	 * return name given.
138 	 */
139 	if (strchr(oname, '/')) {
140 		len = strlen(oname) + 1;
141 		if ((nname = stravl_insert(oname, 0, len, 0)) == NULL)
142 			return (0);
143 	} else {
144 		char	buffer[PATH_MAX];
145 
146 		len = strlen(oname) + 3;
147 		(void) snprintf(buffer, len, MSG_ORIG(MSG_FMT_4XPATH), oname);
148 		if ((nname = stravl_insert(buffer, 0, len, 0)) == NULL)
149 			return (0);
150 	}
151 
152 	if ((pdp = alist_append(alpp, NULL, sizeof (Pdesc), alni)) == NULL)
153 		return (0);
154 
155 	pdp->pd_pname = nname;
156 	pdp->pd_plen = len;
157 	pdp->pd_flags = PD_FLG_PNSLASH;
158 
159 	DBG_CALL(Dbg_file_fixname(LIST(clmp), nname, oname));
160 	return (1);
161 }
162 
163 /*
164  * Determine if we have been given an A_OUT file.  Returns 1 if true.
165  */
166 Fct *
167 /* ARGSUSED1 */
168 aout_verify(caddr_t addr, size_t size, Fdesc *fdp, const char *name,
169     Rej_desc *rej)
170 {
171 	/* LINTED */
172 	struct exec *exec = (struct exec *)addr;
173 
174 	if (size < sizeof (exec) || (exec->a_machtype != M_SPARC) ||
175 	    (N_BADMAG(*exec))) {
176 		return (NULL);
177 	}
178 	return (&aout_fct);
179 }
180 
181 /*
182  * Return the entry point of the A_OUT executable.  Although the entry point
183  * within an ELF file is flexible, the entry point of an A_OUT executable is
184  * always zero.
185  */
186 static Addr
187 aout_entry_point()
188 {
189 	return (0);
190 }
191 
192 /*
193  * Search through the dynamic section for DT_NEEDED entries and perform one
194  * of two functions.  If only the first argument is specified then load the
195  * defined shared object, otherwise add the link map representing the
196  * defined link map the the dlopen list.
197  */
198 static int
199 aout_needed(Lm_list *lml, Aliste lmco, Rt_map *clmp, int *in_nfavl)
200 {
201 	Alist	*palp = NULL;
202 	void	*need;
203 
204 	for (need = &TEXTBASE(clmp)[AOUTDYN(clmp)->v2->ld_need];
205 	    need != &TEXTBASE(clmp)[0];
206 	    need = &TEXTBASE(clmp)[((Lnk_obj *)(need))->lo_next]) {
207 		Rt_map	*nlmp;
208 		char	*name;
209 
210 		name = &TEXTBASE(clmp)[((Lnk_obj *)(need))->lo_name];
211 
212 		if (((Lnk_obj *)(need))->lo_library) {
213 			/*
214 			 * If lo_library field is not NULL then this needed
215 			 * library was linked in using the "-l" option.
216 			 * Thus we need to rebuild the library name before
217 			 * trying to load it.
218 			 */
219 			char	*file;
220 			size_t	len;
221 
222 			/*
223 			 * Allocate name length plus 20 for full library name.
224 			 * lib.so.. = 7 + (2 * short) + NULL = 7 + 12 + 1 = 20
225 			 */
226 			len = strlen(name) + 20;
227 			if ((file = malloc(len)) == NULL)
228 				return (0);
229 			(void) snprintf(file, len, MSG_ORIG(MSG_FMT_4XLIB),
230 			    name, ((Lnk_obj *)(need))->lo_major,
231 			    ((Lnk_obj *)(need))->lo_minor);
232 
233 			DBG_CALL(Dbg_libs_find(lml, file));
234 
235 			/*
236 			 * We need to determine what filename will match the
237 			 * the filename specified (ie, a libc.so.1.2 may match
238 			 * to a libc.so.1.3).  It's the real pathname that is
239 			 * recorded in the link maps.  If we are presently
240 			 * being traced, skip this pathname generation so
241 			 * that we fall through into load_so() to print the
242 			 * appropriate diagnostics.  I don't like this at all.
243 			 */
244 			if (lml->lm_flags & LML_FLG_TRC_ENABLE)
245 				name = file;
246 			else {
247 				Spath_desc	sd = { search_rules, NULL, 0 };
248 				Pdesc		*pdp;
249 				char		*path = NULL;
250 
251 				for (pdp = get_next_dir(&sd, clmp, 0); pdp;
252 				    pdp = get_next_dir(&sd, clmp, 0)) {
253 					if (pdp->pd_pname == 0)
254 						continue;
255 
256 					if (path = aout_get_so(pdp->pd_pname,
257 					    file, 0, 0))
258 						break;
259 				}
260 				if (path == NULL) {
261 					eprintf(lml, ERR_FATAL,
262 					    MSG_INTL(MSG_SYS_OPEN), file,
263 					    strerror(ENOENT));
264 					return (0);
265 				}
266 				name = path;
267 			}
268 			if (expand_paths(clmp, name, &palp,
269 			    AL_CNT_NEEDED, 0, 0) == 0)
270 				return (0);
271 		} else {
272 			/*
273 			 * If the library is specified as a pathname, see if
274 			 * it must be fixed to specify the current working
275 			 * directory (ie. libc.so.1.2 -> ./libc.so.1.2).
276 			 */
277 			if (aout_fix_name(name, clmp, &palp,
278 			    AL_CNT_NEEDED, 0) == 0)
279 				return (0);
280 		}
281 
282 		DBG_CALL(Dbg_file_needed(clmp, name));
283 
284 		nlmp = load_one(lml, lmco, palp, clmp, MODE(clmp), 0, 0,
285 		    in_nfavl);
286 		remove_plist(&palp, 1);
287 		if (((nlmp == 0) || (bind_one(clmp, nlmp, BND_NEEDED) == 0)) &&
288 		    ((lml->lm_flags & LML_FLG_TRC_ENABLE) == 0))
289 			return (0);
290 	}
291 
292 	return (1);
293 }
294 
295 static Sym *
296 aout_symconvert(struct nlist *sp)
297 {
298 	static Sym	sym;
299 
300 	sym.st_value = sp->n_value;
301 	sym.st_size = 0;
302 	sym.st_info = 0;
303 	sym.st_other = 0;
304 	switch (sp->n_type) {
305 		case N_EXT + N_ABS:
306 			sym.st_shndx = SHN_ABS;
307 			break;
308 		case N_COMM:
309 			sym.st_shndx = SHN_COMMON;
310 			break;
311 		case N_EXT + N_UNDF:
312 			sym.st_shndx = SHN_UNDEF;
313 			break;
314 		default:
315 			sym.st_shndx = 0;
316 			break;
317 	}
318 	return (&sym);
319 }
320 
321 /*
322  * Process a.out format commons.
323  */
324 static struct nlist *
325 aout_find_com(struct nlist *sp, const char *name)
326 {
327 	static struct rtc_symb	*rtcp = 0;
328 	struct rtc_symb		*rs, *trs;
329 	const char		*sl;
330 	char			*cp;
331 
332 	/*
333 	 * See if common is already allocated.
334 	 */
335 	trs = rtcp;
336 	while (trs) {
337 		sl = name;
338 		cp = trs->rtc_sp->n_un.n_name;
339 		while (*sl == *cp++)
340 			if (*sl++ == '\0')
341 				return (trs->rtc_sp);
342 		trs = trs->rtc_next;
343 	}
344 
345 	/*
346 	 * If we got here, common is not already allocated so allocate it.
347 	 */
348 	if ((rs = malloc(sizeof (struct rtc_symb))) == NULL)
349 		return (NULL);
350 	if ((rs->rtc_sp = malloc(sizeof (struct nlist))) == NULL)
351 		return (NULL);
352 	trs = rtcp;
353 	rtcp = rs;
354 	rs->rtc_next = trs;
355 	*(rs->rtc_sp) = *sp;
356 	if ((rs->rtc_sp->n_un.n_name = malloc(strlen(name) + 1)) == NULL)
357 		return (NULL);
358 	(void) strcpy(rs->rtc_sp->n_un.n_name, name);
359 	rs->rtc_sp->n_type = N_COMM;
360 	if ((rs->rtc_sp->n_value =
361 	    (long)calloc(rs->rtc_sp->n_value, 1)) == NULL)
362 		return (NULL);
363 	return (rs->rtc_sp);
364 }
365 
366 /*
367  * Find a.out format symbol in the specified link map.  Unlike the sister
368  * elf routine we re-calculate the symbols hash value for each link map
369  * we're looking at.
370  */
371 static struct nlist *
372 aout_findsb(const char *aname, Rt_map *lmp, int flag)
373 {
374 	const char	*name = aname;
375 	char		*cp;
376 	struct fshash	*p;
377 	int		i;
378 	struct nlist	*sp;
379 	ulong_t		hval = 0;
380 
381 #define	HASHMASK	0x7fffffff
382 #define	RTHS		126
383 
384 	/*
385 	 * The name passed to us is in ELF format, thus it is necessary to
386 	 * map this back to the A_OUT format to compute the hash value (see
387 	 * mapping rules in aout_lookup_sym()).  Basically the symbols are
388 	 * mapped according to whether a leading `.' exists.
389 	 *
390 	 *	elf symbol		a.out symbol
391 	 * i.	   .bar		->	   .bar		(LKUP_LDOT)
392 	 * ii.	   .nuts	->	    nuts
393 	 * iii.	    foo		->	   _foo
394 	 */
395 	if (*name == '.') {
396 		if (!(flag & LKUP_LDOT))
397 			name++;
398 	} else
399 		hval = '_';
400 
401 	while (*name)
402 		hval = (hval << 1) + *name++;
403 	hval = hval & HASHMASK;
404 
405 	i = hval % (AOUTDYN(lmp)->v2->ld_buckets == 0 ? RTHS :
406 	    AOUTDYN(lmp)->v2->ld_buckets);
407 	p = LM2LP(lmp)->lp_hash + i;
408 
409 	if (p->fssymbno != -1) {
410 		do {
411 			sp = &LM2LP(lmp)->lp_symtab[p->fssymbno];
412 			cp = &LM2LP(lmp)->lp_symstr[sp->n_un.n_strx];
413 			name = aname;
414 			if (*name == '.') {
415 				if (!(flag & LKUP_LDOT))
416 					name++;
417 			} else {
418 				cp++;
419 			}
420 			while (*name == *cp++) {
421 				if (*name++ == '\0')
422 					return (sp);	/* found */
423 			}
424 			if (p->next == 0)
425 				return (NULL);		/* not found */
426 			else
427 				continue;
428 		} while ((p = &LM2LP(lmp)->lp_hash[p->next]) != 0);
429 	}
430 	return (NULL);
431 }
432 
433 /*
434  * The symbol name we have been asked to look up is in A_OUT format, this
435  * symbol is mapped to the appropriate ELF format which is the standard by
436  * which symbols are passed around ld.so.1.  The symbols are mapped
437  * according to whether a leading `_' or `.' exists.
438  *
439  *	a.out symbol		elf symbol
440  * i.	   _foo		->	    foo
441  * ii.	   .bar		->	   .bar		(LKUP_LDOT)
442  * iii.	    nuts	->	   .nuts
443  */
444 Sym *
445 aout_lookup_sym(Slookup *slp, Rt_map **dlmp, uint_t *binfo, int *in_nfavl)
446 {
447 	char	name[PATH_MAX];
448 	Slookup	sl = *slp;
449 
450 	DBG_CALL(Dbg_syms_lookup_aout(LIST(slp->sl_cmap), slp->sl_name));
451 
452 	if (*sl.sl_name == '_')
453 		++sl.sl_name;
454 	else if (*sl.sl_name == '.')
455 		sl.sl_flags |= LKUP_LDOT;
456 	else {
457 		name[0] = '.';
458 		(void) strcpy(&name[1], sl.sl_name);
459 		sl.sl_name = name;
460 	}
461 
462 	/*
463 	 * Call the generic lookup routine to cycle through the specified
464 	 * link maps.
465 	 */
466 	return (lookup_sym(&sl, dlmp, binfo, in_nfavl));
467 }
468 
469 /*
470  * Symbol lookup for an a.out format module.
471  */
472 /* ARGSUSED3 */
473 static Sym *
474 aout_find_sym(Slookup *slp, Rt_map **dlmp, uint_t *binfo, int *in_nfavl)
475 {
476 	const char	*name = slp->sl_name;
477 	Rt_map		*ilmp = slp->sl_imap;
478 	struct nlist	*sp;
479 
480 	DBG_CALL(Dbg_syms_lookup(ilmp, name, MSG_ORIG(MSG_STR_AOUT)));
481 
482 	if (sp = aout_findsb(name, ilmp, slp->sl_flags)) {
483 		if (sp->n_value != 0) {
484 			/*
485 			 * is it a common?
486 			 */
487 			if (sp->n_type == (N_EXT + N_UNDF)) {
488 				if ((sp = aout_find_com(sp, name)) == 0)
489 					return (NULL);
490 			}
491 			*dlmp = ilmp;
492 			*binfo |= DBG_BINFO_FOUND;
493 			return (aout_symconvert(sp));
494 		}
495 	}
496 	return (NULL);
497 }
498 
499 /*
500  * Create a new Rt_map structure for an a.out format object and
501  * initializes all values.
502  */
503 /* ARGSUSED6 */
504 Rt_map *
505 aout_new_lmp(Lm_list *lml, Aliste lmco, Fdesc *fdp, Addr addr, size_t msize,
506     void *odyn, int *in_nfavl)
507 {
508 	const char	*name = fdp->fd_nname;
509 	Rt_map		*lmp;
510 	caddr_t		base, caddr = (caddr_t)addr;
511 	Link_dynamic	*ld = (Link_dynamic *)odyn;
512 	size_t		lmsz, rtsz, prsz;
513 
514 	DBG_CALL(Dbg_file_aout(lml, name, addr, msize, lml->lm_lmidstr, lmco));
515 
516 	/*
517 	 * Allocate space for the link-map and private a.out information.  Once
518 	 * these are allocated and initialized, we can use remove_so(0, lmp) to
519 	 * tear down the link-map should any failures occur.
520 	 */
521 	rtsz = S_DROUND(sizeof (Rt_map));
522 	prsz = S_DROUND(sizeof (Rt_aoutp));
523 	lmsz = rtsz + prsz + sizeof (struct ld_private);
524 	if ((lmp = calloc(lmsz, 1)) == NULL)
525 		return (NULL);
526 	AOUTPRV(lmp) = (void *)((uintptr_t)lmp + rtsz);
527 	((Rt_aoutp *)AOUTPRV(lmp))->lm_lpd =
528 	    (void *)((uintptr_t)lmp + rtsz + prsz);
529 	LMSIZE(lmp) = lmsz;
530 
531 	/*
532 	 * All fields not filled in were set to 0 by calloc.
533 	 */
534 	NAME(lmp) = (char *)name;
535 	ADDR(lmp) = addr;
536 	MSIZE(lmp) = msize;
537 	SYMINTP(lmp) = aout_find_sym;
538 	FCT(lmp) = &aout_fct;
539 	LIST(lmp) = lml;
540 	OBJFLTRNDX(lmp) = FLTR_DISABLED;
541 	SORTVAL(lmp) = -1;
542 
543 	/*
544 	 * Specific settings for a.out format.
545 	 */
546 	if (lml->lm_head == 0) {
547 		base = (caddr_t)MAIN_BASE;
548 		FLAGS(lmp) |= FLG_RT_FIXED;
549 	} else
550 		base = caddr;
551 
552 	/*
553 	 * Fill in all AOUT information.  Applications provide the Link_dynamic
554 	 * offset via the boot block, but if this is a shared object that
555 	 * ld.so.1 has mapped, then determine the Link_dynamic offset from the
556 	 * mapped image.
557 	 */
558 	if (ld == NULL) {
559 		/* LINTED */
560 		struct exec	*exec = (struct exec *)caddr;
561 		struct nlist	*nl;
562 
563 		/* LINTED */
564 		nl = (struct nlist *)&caddr[N_SYMOFF(*exec)];
565 		/* LINTED */
566 		ld = (Link_dynamic *)&caddr[nl->n_value];
567 
568 		ld->v2 = (struct link_dynamic_2 *)((int)ld->v2 + (int)caddr);
569 	}
570 	AOUTDYN(lmp) = ld;
571 
572 	if ((RPATH(lmp) = (char *)&base[ld->v2->ld_rules]) == base)
573 		RPATH(lmp) = 0;
574 	LM2LP(lmp)->lp_symbol_base = caddr;
575 	/* LINTED */
576 	LM2LP(lmp)->lp_plt = (struct jbind *)(&caddr[JMPOFF(ld)]);
577 	LM2LP(lmp)->lp_rp =
578 	/* LINTED */
579 	    (struct relocation_info *)(&base[RELOCOFF(ld)]);
580 	/* LINTED */
581 	LM2LP(lmp)->lp_hash = (struct fshash *)(&base[HASHOFF(ld)]);
582 	/* LINTED */
583 	LM2LP(lmp)->lp_symtab = (struct nlist *)(&base[SYMOFF(ld)]);
584 	LM2LP(lmp)->lp_symstr = &base[STROFF(ld)];
585 	LM2LP(lmp)->lp_textbase = base;
586 	LM2LP(lmp)->lp_refcnt++;
587 	LM2LP(lmp)->lp_dlp = NULL;
588 
589 	/*
590 	 * Add the mapped object to the end of the link map list.
591 	 */
592 	lm_append(lml, lmco, lmp);
593 	return (lmp);
594 }
595 
596 /*
597  * Build full pathname of shared object from the given directory name and
598  * filename.
599  */
600 static char *
601 /* ARGSUSED2 */
602 aout_get_so(const char *dir, const char *file, size_t dlen, size_t flen)
603 {
604 	struct db	*dbp;
605 	char		*path = NULL;
606 
607 	if (dbp = lo_cache(dir)) {
608 		path = ask_db(dbp, file);
609 	}
610 	return (path);
611 }
612 
613 /*
614  * Determine the symbol location of an address within a link-map.  Look for
615  * the nearest symbol (whoes value is less than or equal to the required
616  * address).  This is the object specific part of dladdr().
617  */
618 static void
619 aout_dladdr(ulong_t addr, Rt_map *lmp, Dl_info *dlip, void **info,
620     int flags)
621 {
622 	ulong_t		ndx, cnt, base, _value;
623 	struct nlist	*sym, *_sym;
624 
625 	cnt = ((int)LM2LP(lmp)->lp_symstr - (int)LM2LP(lmp)->lp_symtab) /
626 	    sizeof (struct nlist);
627 	sym = LM2LP(lmp)->lp_symtab;
628 
629 	if (FLAGS(lmp) & FLG_RT_FIXED)
630 		base = 0;
631 	else
632 		base = ADDR(lmp);
633 
634 	for (_sym = 0, _value = 0, ndx = 0; ndx < cnt; ndx++, sym++) {
635 		ulong_t	value;
636 
637 		if (sym->n_type == (N_EXT + N_UNDF))
638 			continue;
639 
640 		value = sym->n_value + base;
641 		if (value > addr)
642 			continue;
643 		if (value < _value)
644 			continue;
645 
646 		_sym = sym;
647 		_value = value;
648 
649 		if (value == addr)
650 			break;
651 	}
652 
653 	if (_sym) {
654 		int	_flags = flags & RTLD_DL_MASK;
655 
656 		/*
657 		 * The only way we can create a symbol entry is to use
658 		 * aout_symconvert(), however this results in us pointing to
659 		 * static data that could be overridden.  In addition the AOUT
660 		 * symbol format doesn't give us everything an ELF symbol does.
661 		 * So, unless we get convinced otherwise, don't bother returning
662 		 * a symbol entry for AOUT's.
663 		 */
664 		if (_flags == RTLD_DL_SYMENT)
665 			*info = 0;
666 		else if (_flags == RTLD_DL_LINKMAP)
667 			*info = (void *)lmp;
668 
669 		dlip->dli_sname = &LM2LP(lmp)->lp_symstr[_sym->n_un.n_strx];
670 		dlip->dli_saddr = (void *)_value;
671 	}
672 }
673 
674 /*
675  * Continue processing a dlsym request.  Lookup the required symbol in each
676  * link-map specified by the handle.  Note, that because this lookup is against
677  * individual link-maps we don't need to supply a starting link-map to the
678  * lookup routine (see lookup_sym():analyze.c).
679  */
680 static Sym *
681 aout_dlsym_handle(Grp_hdl *ghp, Slookup *slp, Rt_map **_lmp, uint_t *binfo,
682     int *in_nfavl)
683 {
684 	Sym	*sym;
685 	char	buffer[PATH_MAX];
686 	Slookup	sl;
687 
688 	buffer[0] = '_';
689 	(void) strcpy(&buffer[1], slp->sl_name);
690 
691 	if ((sym = dlsym_handle(ghp, slp, _lmp, binfo, in_nfavl)) != 0)
692 		return (sym);
693 
694 	/*
695 	 * Symbol not found as supplied.  However, most of our symbols will
696 	 * be in the "C" name space, where the implementation prepends a "_"
697 	 * to the symbol as it emits it.  Therefore, attempt to find the
698 	 * symbol with the "_" prepend.
699 	 */
700 	sl = *slp;
701 	sl.sl_name = (const char *)buffer;
702 
703 	return (dlsym_handle(ghp, &sl, _lmp, binfo, in_nfavl));
704 }
705 
706 /*
707  * The initial mapping of the a.out occurs through exec(2), and presently this
708  * implementation doesn't provide a mmapobj_result_t array to ld.so.1.  Thus,
709  * aout_get_mmap() is called to create the mapping information.  Unlike ELF,
710  * the information that can be gathered from a mapped AOUT file, can be limited.
711  * In some cases the AOUT header isn't available in the mapped image, and thus
712  * this can't be inspected to determine the files size (the kernel always
713  * returns a pointer to the AOUT dynamic structure, but this is only sufficient
714  * to determine the size of the text segment).
715  *
716  * Therefore, the only generic mechanism of determining the AOUT's mapping is
717  * to use /proc.  Only two mappings are required, the text (to determine any
718  * read-only region), and the data.  The two mapping validate the range in
719  * which any relocations will occur.  Should there be an additional bss segment,
720  * we don't care, as this can't be relocated, and we're never going to try
721  * unmapping the a.out.
722  */
723 int
724 aout_get_mmap(Lm_list *lml, mmapobj_result_t *mpp)
725 {
726 	prmap_t	*maps;
727 	char	proc[16];
728 	int	num, err, fd;
729 
730 	(void) snprintf(proc, 16, MSG_ORIG(MSG_FMT_PROC), (int)getpid());
731 	if ((fd = open(proc, O_RDONLY)) == -1) {
732 		err = errno;
733 		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_SYS_OPEN), proc,
734 		    strerror(err));
735 		return (1);
736 	}
737 
738 	if (ioctl(fd, PIOCNMAP, (void *)&num) == -1) {
739 		err = errno;
740 		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_SYS_PROC), strerror(err));
741 		return (1);
742 	}
743 
744 	if ((maps = malloc((num + 1) * sizeof (prmap_t))) == NULL)
745 		return (1);
746 
747 	if (ioctl(fd, PIOCMAP, (void *)maps) == -1) {
748 		err = errno;
749 		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_SYS_PROC), strerror(err));
750 		free(maps);
751 		return (1);
752 	}
753 
754 	mpp->mr_addr = maps->pr_vaddr;
755 	mpp->mr_fsize = mpp->mr_msize = maps->pr_size;
756 	mpp->mr_prot = (PROT_READ | PROT_EXEC);
757 
758 	mpp++, maps++;
759 
760 	mpp->mr_addr = maps->pr_vaddr;
761 	mpp->mr_fsize = mpp->mr_msize = maps->pr_size;
762 	mpp->mr_prot = (PROT_READ | PROT_WRITE | PROT_EXEC);
763 
764 	maps--;
765 	free(maps);
766 	return (0);
767 }
768