i386_elf.c revision 6206:6b0ed502a8e7
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 (c) 1988 AT&T
24 *	  All Rights Reserved
25 *
26 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
27 * Use is subject to license terms.
28 */
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31/*
32 * x86 machine dependent and ELF file class dependent functions.
33 * Contains routines for performing function binding and symbol relocations.
34 */
35#include	"_synonyms.h"
36
37#include	<stdio.h>
38#include	<sys/elf.h>
39#include	<sys/elf_386.h>
40#include	<sys/mman.h>
41#include	<dlfcn.h>
42#include	<synch.h>
43#include	<string.h>
44#include	<debug.h>
45#include	<reloc.h>
46#include	<conv.h>
47#include	"_rtld.h"
48#include	"_audit.h"
49#include	"_elf.h"
50#include	"msg.h"
51
52
53extern void	elf_rtbndr(Rt_map *, ulong_t, caddr_t);
54
55int
56elf_mach_flags_check(Rej_desc *rej, Ehdr *ehdr)
57{
58	/*
59	 * Check machine type and flags.
60	 */
61	if (ehdr->e_flags != 0) {
62		rej->rej_type = SGS_REJ_BADFLAG;
63		rej->rej_info = (uint_t)ehdr->e_flags;
64		return (0);
65	}
66	return (1);
67}
68
69void
70ldso_plt_init(Rt_map * lmp)
71{
72	/*
73	 * There is no need to analyze ld.so because we don't map in any of
74	 * its dependencies.  However we may map these dependencies in later
75	 * (as if ld.so had dlopened them), so initialize the plt and the
76	 * permission information.
77	 */
78	if (PLTGOT(lmp))
79		elf_plt_init((PLTGOT(lmp)), (caddr_t)lmp);
80}
81
82static const uchar_t dyn_plt_template[] = {
83/* 0x00 */  0x55,				/* pushl %ebp */
84/* 0x01 */  0x8b, 0xec,				/* movl %esp, %ebp */
85/* 0x03 */  0x68, 0x00, 0x00, 0x00, 0x00,	/* pushl trace_fields */
86/* 0x08 */  0xe9, 0xfc, 0xff, 0xff, 0xff, 0xff	/* jmp  elf_plt_trace */
87};
88int	dyn_plt_ent_size = sizeof (dyn_plt_template);
89
90/*
91 * the dynamic plt entry is:
92 *
93 *	pushl	%ebp
94 *	movl	%esp, %ebp
95 *	pushl	tfp
96 *	jmp	elf_plt_trace
97 * dyn_data:
98 *	.align  4
99 *	uintptr_t	reflmp
100 *	uintptr_t	deflmp
101 *	uint_t		symndx
102 *	uint_t		sb_flags
103 *	Sym		symdef
104 */
105static caddr_t
106elf_plt_trace_write(uint_t roffset, Rt_map *rlmp, Rt_map *dlmp, Sym *sym,
107    uint_t symndx, uint_t pltndx, caddr_t to, uint_t sb_flags, int *fail)
108{
109	extern int	elf_plt_trace();
110	ulong_t		got_entry;
111	uchar_t		*dyn_plt;
112	uintptr_t	*dyndata;
113
114	/*
115	 * We only need to add the glue code if there is an auditing
116	 * library that is interested in this binding.
117	 */
118	dyn_plt = (uchar_t *)((uintptr_t)AUDINFO(rlmp)->ai_dynplts +
119	    (pltndx * dyn_plt_ent_size));
120
121	/*
122	 * Have we initialized this dynamic plt entry yet?  If we haven't do it
123	 * now.  Otherwise this function has been called before, but from a
124	 * different plt (ie. from another shared object).  In that case
125	 * we just set the plt to point to the new dyn_plt.
126	 */
127	if (*dyn_plt == 0) {
128		Sym	*symp;
129		Word	symvalue;
130		Lm_list	*lml = LIST(rlmp);
131
132		(void) memcpy((void *)dyn_plt, dyn_plt_template,
133		    sizeof (dyn_plt_template));
134		dyndata = (uintptr_t *)((uintptr_t)dyn_plt +
135		    ROUND(sizeof (dyn_plt_template), M_WORD_ALIGN));
136
137		/*
138		 * relocate:
139		 *	pushl	dyn_data
140		 */
141		symvalue = (Word)dyndata;
142		if (do_reloc_rtld(R_386_32, &dyn_plt[4], &symvalue,
143		    MSG_ORIG(MSG_SYM_LADYNDATA),
144		    MSG_ORIG(MSG_SPECFIL_DYNPLT), lml) == 0) {
145			*fail = 1;
146			return (0);
147		}
148
149		/*
150		 * jmps are relative, so I need to figure out the relative
151		 * address to elf_plt_trace.
152		 *
153		 * relocating:
154		 *	jmp	elf_plt_trace
155		 */
156		symvalue = (ulong_t)(elf_plt_trace) - (ulong_t)(dyn_plt + 9);
157		if (do_reloc_rtld(R_386_PC32, &dyn_plt[9], &symvalue,
158		    MSG_ORIG(MSG_SYM_ELFPLTTRACE),
159		    MSG_ORIG(MSG_SPECFIL_DYNPLT), lml) == 0) {
160			*fail = 1;
161			return (0);
162		}
163
164		*dyndata++ = (uintptr_t)rlmp;
165		*dyndata++ = (uintptr_t)dlmp;
166		*dyndata++ = (uint_t)symndx;
167		*dyndata++ = (uint_t)sb_flags;
168		symp = (Sym *)dyndata;
169		*symp = *sym;
170		symp->st_name += (Word)STRTAB(dlmp);
171		symp->st_value = (Addr)to;
172	}
173
174	got_entry = (ulong_t)roffset;
175	*(ulong_t *)got_entry = (ulong_t)dyn_plt;
176	return ((caddr_t)dyn_plt);
177}
178
179
180/*
181 * Function binding routine - invoked on the first call to a function through
182 * the procedure linkage table;
183 * passes first through an assembly language interface.
184 *
185 * Takes the offset into the relocation table of the associated
186 * relocation entry and the address of the link map (rt_private_map struct)
187 * for the entry.
188 *
189 * Returns the address of the function referenced after re-writing the PLT
190 * entry to invoke the function directly.
191 *
192 * On error, causes process to terminate with a signal.
193 */
194ulong_t
195elf_bndr(Rt_map *lmp, ulong_t reloff, caddr_t from)
196{
197	Rt_map		*nlmp, *llmp;
198	ulong_t		addr, symval, rsymndx;
199	char		*name;
200	Rel		*rptr;
201	Sym		*rsym, *nsym;
202	uint_t		binfo, sb_flags = 0, dbg_class;
203	Slookup		sl;
204	int		entry, lmflags;
205	Lm_list		*lml;
206
207	/*
208	 * For compatibility with libthread (TI_VERSION 1) we track the entry
209	 * value.  A zero value indicates we have recursed into ld.so.1 to
210	 * further process a locking request.  Under this recursion we disable
211	 * tsort and cleanup activities.
212	 */
213	entry = enter();
214
215	lml = LIST(lmp);
216	if ((lmflags = lml->lm_flags) & LML_FLG_RTLDLM) {
217		dbg_class = dbg_desc->d_class;
218		dbg_desc->d_class = 0;
219	}
220
221	/*
222	 * Perform some basic sanity checks.  If we didn't get a load map or
223	 * the relocation offset is invalid then its possible someone has walked
224	 * over the .got entries or jumped to plt0 out of the blue.
225	 */
226	if (!lmp || ((reloff % sizeof (Rel)) != 0)) {
227		Conv_inv_buf_t inv_buf;
228
229		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_REL_PLTREF),
230		    conv_reloc_386_type(R_386_JMP_SLOT, 0, &inv_buf),
231		    EC_NATPTR(lmp), EC_XWORD(reloff), EC_NATPTR(from));
232		rtldexit(lml, 1);
233	}
234
235	/*
236	 * Use relocation entry to get symbol table entry and symbol name.
237	 */
238	addr = (ulong_t)JMPREL(lmp);
239	rptr = (Rel *)(addr + reloff);
240	rsymndx = ELF_R_SYM(rptr->r_info);
241	rsym = (Sym *)((ulong_t)SYMTAB(lmp) + (rsymndx * SYMENT(lmp)));
242	name = (char *)(STRTAB(lmp) + rsym->st_name);
243
244	/*
245	 * Determine the last link-map of this list, this'll be the starting
246	 * point for any tsort() processing.
247	 */
248	llmp = lml->lm_tail;
249
250	/*
251	 * Find definition for symbol.  Initialize the symbol lookup data
252	 * structure.
253	 */
254	SLOOKUP_INIT(sl, name, lmp, lml->lm_head, ld_entry_cnt, 0,
255	    rsymndx, rsym, 0, LKUP_DEFT);
256
257	if ((nsym = lookup_sym(&sl, &nlmp, &binfo)) == 0) {
258		eprintf(lml, ERR_FATAL, MSG_INTL(MSG_REL_NOSYM), NAME(lmp),
259		    demangle(name));
260		rtldexit(lml, 1);
261	}
262
263	symval = nsym->st_value;
264	if (!(FLAGS(nlmp) & FLG_RT_FIXED) &&
265	    (nsym->st_shndx != SHN_ABS))
266		symval += ADDR(nlmp);
267	if ((lmp != nlmp) && ((FLAGS1(nlmp) & FL1_RT_NOINIFIN) == 0)) {
268		/*
269		 * Record that this new link map is now bound to the caller.
270		 */
271		if (bind_one(lmp, nlmp, BND_REFER) == 0)
272			rtldexit(lml, 1);
273	}
274
275	if ((lml->lm_tflags | FLAGS1(lmp)) & LML_TFLG_AUD_SYMBIND) {
276		uint_t	symndx = (((uintptr_t)nsym -
277		    (uintptr_t)SYMTAB(nlmp)) / SYMENT(nlmp));
278		symval = audit_symbind(lmp, nlmp, nsym, symndx, symval,
279		    &sb_flags);
280	}
281
282	if (!(rtld_flags & RT_FL_NOBIND)) {
283		addr = rptr->r_offset;
284		if (!(FLAGS(lmp) & FLG_RT_FIXED))
285			addr += ADDR(lmp);
286		if (((lml->lm_tflags | FLAGS1(lmp)) &
287		    (LML_TFLG_AUD_PLTENTER | LML_TFLG_AUD_PLTEXIT)) &&
288		    AUDINFO(lmp)->ai_dynplts) {
289			int	fail = 0;
290			uint_t	pltndx = reloff / sizeof (Rel);
291			uint_t	symndx = (((uintptr_t)nsym -
292			    (uintptr_t)SYMTAB(nlmp)) / SYMENT(nlmp));
293
294			symval = (ulong_t)elf_plt_trace_write(addr, lmp, nlmp,
295			    nsym, symndx, pltndx, (caddr_t)symval, sb_flags,
296			    &fail);
297			if (fail)
298				rtldexit(lml, 1);
299		} else {
300			/*
301			 * Write standard PLT entry to jump directly
302			 * to newly bound function.
303			 */
304			*(ulong_t *)addr = symval;
305		}
306	}
307
308	/*
309	 * Print binding information and rebuild PLT entry.
310	 */
311	DBG_CALL(Dbg_bind_global(lmp, (Addr)from, (Off)(from - ADDR(lmp)),
312	    (Xword)(reloff / sizeof (Rel)), PLT_T_FULL, nlmp, (Addr)symval,
313	    nsym->st_value, name, binfo));
314
315	/*
316	 * Complete any processing for newly loaded objects.  Note we don't
317	 * know exactly where any new objects are loaded (we know the object
318	 * that supplied the symbol, but others may have been loaded lazily as
319	 * we searched for the symbol), so sorting starts from the last
320	 * link-map know on entry to this routine.
321	 */
322	if (entry)
323		load_completion(llmp);
324
325	/*
326	 * Some operations like dldump() or dlopen()'ing a relocatable object
327	 * result in objects being loaded on rtld's link-map, make sure these
328	 * objects are initialized also.
329	 */
330	if ((LIST(nlmp)->lm_flags & LML_FLG_RTLDLM) && LIST(nlmp)->lm_init)
331		load_completion(nlmp);
332
333	/*
334	 * If the object we've bound to is in the process of being initialized
335	 * by another thread, determine whether we should block.
336	 */
337	is_dep_ready(nlmp, lmp, DBG_WAIT_SYMBOL);
338
339	/*
340	 * Make sure the object to which we've bound has had it's .init fired.
341	 * Cleanup before return to user code.
342	 */
343	if (entry) {
344		is_dep_init(nlmp, lmp);
345		leave(lml);
346	}
347
348	if (lmflags & LML_FLG_RTLDLM)
349		dbg_desc->d_class = dbg_class;
350
351	return (symval);
352}
353
354
355/*
356 * When the relocation loop realizes that it's dealing with relative
357 * relocations in a shared object, it breaks into this tighter loop
358 * as an optimization.
359 */
360ulong_t
361elf_reloc_relative(ulong_t relbgn, ulong_t relend, ulong_t relsiz,
362    ulong_t basebgn, ulong_t etext, ulong_t emap)
363{
364	ulong_t roffset = ((Rel *)relbgn)->r_offset;
365	char rtype;
366
367	do {
368		roffset += basebgn;
369
370		/*
371		 * If this relocation is against an address not mapped in,
372		 * then break out of the relative relocation loop, falling
373		 * back on the main relocation loop.
374		 */
375		if (roffset < etext || roffset > emap)
376			break;
377
378		/*
379		 * Perform the actual relocation.
380		 */
381		*((ulong_t *)roffset) += basebgn;
382
383		relbgn += relsiz;
384
385		if (relbgn >= relend)
386			break;
387
388		rtype = ELF_R_TYPE(((Rel *)relbgn)->r_info, M_MACH);
389		roffset = ((Rel *)relbgn)->r_offset;
390
391	} while (rtype == R_386_RELATIVE);
392
393	return (relbgn);
394}
395
396/*
397 * This is the tightest loop for RELATIVE relocations for those
398 * objects built with the DT_RELACOUNT .dynamic entry.
399 */
400ulong_t
401elf_reloc_relacount(ulong_t relbgn, ulong_t relacount, ulong_t relsiz,
402    ulong_t basebgn)
403{
404	ulong_t roffset = ((Rel *) relbgn)->r_offset;
405
406	for (; relacount; relacount--) {
407		roffset += basebgn;
408
409		/*
410		 * Perform the actual relocation.
411		 */
412		*((ulong_t *)roffset) += basebgn;
413
414		relbgn += relsiz;
415
416		roffset = ((Rel *)relbgn)->r_offset;
417
418	}
419
420	return (relbgn);
421}
422
423/*
424 * Read and process the relocations for one link object, we assume all
425 * relocation sections for loadable segments are stored contiguously in
426 * the file.
427 */
428int
429elf_reloc(Rt_map *lmp, uint_t plt)
430{
431	ulong_t		relbgn, relend, relsiz, basebgn;
432	ulong_t		pltbgn, pltend, _pltbgn, _pltend;
433	ulong_t		roffset, rsymndx, psymndx = 0, etext  = ETEXT(lmp);
434	ulong_t		emap, dsymndx;
435	uchar_t		rtype;
436	long		value, pvalue;
437	Sym		*symref, *psymref, *symdef, *psymdef;
438	char		*name, *pname;
439	Rt_map		*_lmp, *plmp;
440	int		textrel = 0, ret = 1, noplt = 0;
441	int		relacount = RELACOUNT(lmp), plthint = 0;
442	Rel		*rel;
443	uint_t		binfo, pbinfo;
444	APlist		*bound = NULL;
445
446	/*
447	 * Although only necessary for lazy binding, initialize the first
448	 * global offset entry to go to elf_rtbndr().  dbx(1) seems
449	 * to find this useful.
450	 */
451	if ((plt == 0) && PLTGOT(lmp)) {
452		if ((ulong_t)PLTGOT(lmp) < etext) {
453			if (elf_set_prot(lmp, PROT_WRITE) == 0)
454				return (0);
455			textrel = 1;
456		}
457		elf_plt_init(PLTGOT(lmp), (caddr_t)lmp);
458	}
459
460	/*
461	 * Initialize the plt start and end addresses.
462	 */
463	if ((pltbgn = (ulong_t)JMPREL(lmp)) != 0)
464		pltend = pltbgn + (ulong_t)(PLTRELSZ(lmp));
465
466
467	relsiz = (ulong_t)(RELENT(lmp));
468	basebgn = ADDR(lmp);
469	emap = ADDR(lmp) + MSIZE(lmp);
470
471	if (PLTRELSZ(lmp))
472		plthint = PLTRELSZ(lmp) / relsiz;
473
474	/*
475	 * If we've been called upon to promote an RTLD_LAZY object to an
476	 * RTLD_NOW then we're only interested in scaning the .plt table.
477	 * An uninitialized .plt is the case where the associated got entry
478	 * points back to the plt itself.  Determine the range of the real .plt
479	 * entries using the _PROCEDURE_LINKAGE_TABLE_ symbol.
480	 */
481	if (plt) {
482		Slookup	sl;
483
484		relbgn = pltbgn;
485		relend = pltend;
486		if (!relbgn || (relbgn == relend))
487			return (1);
488
489		/*
490		 * Initialize the symbol lookup data structure.
491		 */
492		SLOOKUP_INIT(sl, MSG_ORIG(MSG_SYM_PLT), lmp, lmp, ld_entry_cnt,
493		    elf_hash(MSG_ORIG(MSG_SYM_PLT)), 0, 0, 0, LKUP_DEFT);
494
495		if ((symdef = elf_find_sym(&sl, &_lmp, &binfo)) == 0)
496			return (1);
497
498		_pltbgn = symdef->st_value;
499		if (!(FLAGS(lmp) & FLG_RT_FIXED) &&
500		    (symdef->st_shndx != SHN_ABS))
501			_pltbgn += basebgn;
502		_pltend = _pltbgn + (((PLTRELSZ(lmp) / relsiz)) *
503		    M_PLT_ENTSIZE) + M_PLT_RESERVSZ;
504
505	} else {
506		/*
507		 * The relocation sections appear to the run-time linker as a
508		 * single table.  Determine the address of the beginning and end
509		 * of this table.  There are two different interpretations of
510		 * the ABI at this point:
511		 *
512		 *   o	The REL table and its associated RELSZ indicate the
513		 *	concatenation of *all* relocation sections (this is the
514		 *	model our link-editor constructs).
515		 *
516		 *   o	The REL table and its associated RELSZ indicate the
517		 *	concatenation of all *but* the .plt relocations.  These
518		 *	relocations are specified individually by the JMPREL and
519		 *	PLTRELSZ entries.
520		 *
521		 * Determine from our knowledege of the relocation range and
522		 * .plt range, the range of the total relocation table.  Note
523		 * that one other ABI assumption seems to be that the .plt
524		 * relocations always follow any other relocations, the
525		 * following range checking drops that assumption.
526		 */
527		relbgn = (ulong_t)(REL(lmp));
528		relend = relbgn + (ulong_t)(RELSZ(lmp));
529		if (pltbgn) {
530			if (!relbgn || (relbgn > pltbgn))
531				relbgn = pltbgn;
532			if (!relbgn || (relend < pltend))
533				relend = pltend;
534		}
535	}
536	if (!relbgn || (relbgn == relend)) {
537		DBG_CALL(Dbg_reloc_run(lmp, 0, plt, DBG_REL_NONE));
538		return (1);
539	}
540	DBG_CALL(Dbg_reloc_run(lmp, M_REL_SHT_TYPE, plt, DBG_REL_START));
541
542	/*
543	 * If we're processing a dynamic executable in lazy mode there is no
544	 * need to scan the .rel.plt table, however if we're processing a shared
545	 * object in lazy mode the .got addresses associated to each .plt must
546	 * be relocated to reflect the location of the shared object.
547	 */
548	if (pltbgn && ((MODE(lmp) & RTLD_NOW) == 0) &&
549	    (FLAGS(lmp) & FLG_RT_FIXED))
550		noplt = 1;
551
552	/*
553	 * Loop through relocations.
554	 */
555	while (relbgn < relend) {
556		uint_t	sb_flags = 0;
557
558		rtype = ELF_R_TYPE(((Rel *)relbgn)->r_info, M_MACH);
559
560		/*
561		 * If this is a RELATIVE relocation in a shared object (the
562		 * common case), and if we are not debugging, then jump into a
563		 * tighter relocation loop (elf_reloc_relative).  Only make the
564		 * jump if we've been given a hint on the number of relocations.
565		 */
566		if ((rtype == R_386_RELATIVE) &&
567		    ((FLAGS(lmp) & FLG_RT_FIXED) == 0) && (DBG_ENABLED == 0)) {
568			/*
569			 * It's possible that the relative relocation block
570			 * has relocations against the text segment as well
571			 * as the data segment.  Since our optimized relocation
572			 * engine does not check which segment the relocation
573			 * is against - just mprotect it now if it's been
574			 * marked as containing TEXTREL's.
575			 */
576			if ((textrel == 0) && (FLAGS1(lmp) & FL1_RT_TEXTREL)) {
577				if (elf_set_prot(lmp, PROT_WRITE) == 0) {
578					ret = 0;
579					break;
580				}
581				textrel = 1;
582			}
583
584			if (relacount) {
585				relbgn = elf_reloc_relacount(relbgn, relacount,
586				    relsiz, basebgn);
587				relacount = 0;
588			} else {
589				relbgn = elf_reloc_relative(relbgn, relend,
590				    relsiz, basebgn, etext, emap);
591			}
592			if (relbgn >= relend)
593				break;
594			rtype = ELF_R_TYPE(((Rel *)relbgn)->r_info, M_MACH);
595		}
596
597		roffset = ((Rel *)relbgn)->r_offset;
598
599		/*
600		 * If this is a shared object, add the base address to offset.
601		 */
602		if (!(FLAGS(lmp) & FLG_RT_FIXED)) {
603
604			/*
605			 * If we're processing lazy bindings, we have to step
606			 * through the plt entries and add the base address
607			 * to the corresponding got entry.
608			 */
609			if (plthint && (plt == 0) &&
610			    (rtype == R_386_JMP_SLOT) &&
611			    ((MODE(lmp) & RTLD_NOW) == 0)) {
612				relbgn = elf_reloc_relacount(relbgn,
613				    plthint, relsiz, basebgn);
614				plthint = 0;
615				continue;
616			}
617			roffset += basebgn;
618		}
619
620		rsymndx = ELF_R_SYM(((Rel *)relbgn)->r_info);
621		rel = (Rel *)relbgn;
622		relbgn += relsiz;
623
624		/*
625		 * Optimizations.
626		 */
627		if (rtype == R_386_NONE)
628			continue;
629		if (noplt && ((ulong_t)rel >= pltbgn) &&
630		    ((ulong_t)rel < pltend)) {
631			relbgn = pltend;
632			continue;
633		}
634
635		/*
636		 * If we're promoting plts determine if this one has already
637		 * been written.
638		 */
639		if (plt) {
640			if ((*(ulong_t *)roffset < _pltbgn) ||
641			    (*(ulong_t *)roffset > _pltend))
642				continue;
643		}
644
645		/*
646		 * If this relocation is not against part of the image
647		 * mapped into memory we skip it.
648		 */
649		if ((roffset < ADDR(lmp)) || (roffset > (ADDR(lmp) +
650		    MSIZE(lmp)))) {
651			elf_reloc_bad(lmp, (void *)rel, rtype, roffset,
652			    rsymndx);
653			continue;
654		}
655
656		binfo = 0;
657		/*
658		 * If a symbol index is specified then get the symbol table
659		 * entry, locate the symbol definition, and determine its
660		 * address.
661		 */
662		if (rsymndx) {
663			/*
664			 * Get the local symbol table entry.
665			 */
666			symref = (Sym *)((ulong_t)SYMTAB(lmp) +
667			    (rsymndx * SYMENT(lmp)));
668
669			/*
670			 * If this is a local symbol, just use the base address.
671			 * (we should have no local relocations in the
672			 * executable).
673			 */
674			if (ELF_ST_BIND(symref->st_info) == STB_LOCAL) {
675				value = basebgn;
676				name = (char *)0;
677
678				/*
679				 * Special case TLS relocations.
680				 */
681				if (rtype == R_386_TLS_DTPMOD32) {
682					/*
683					 * Use the TLS modid.
684					 */
685					value = TLSMODID(lmp);
686
687				} else if (rtype == R_386_TLS_TPOFF) {
688					if ((value = elf_static_tls(lmp, symref,
689					    rel, rtype, 0, roffset, 0)) == 0) {
690						ret = 0;
691						break;
692					}
693				}
694			} else {
695				/*
696				 * If the symbol index is equal to the previous
697				 * symbol index relocation we processed then
698				 * reuse the previous values. (Note that there
699				 * have been cases where a relocation exists
700				 * against a copy relocation symbol, our ld(1)
701				 * should optimize this away, but make sure we
702				 * don't use the same symbol information should
703				 * this case exist).
704				 */
705				if ((rsymndx == psymndx) &&
706				    (rtype != R_386_COPY)) {
707					/* LINTED */
708					if (psymdef == 0) {
709						DBG_CALL(Dbg_bind_weak(lmp,
710						    (Addr)roffset, (Addr)
711						    (roffset - basebgn), name));
712						continue;
713					}
714					/* LINTED */
715					value = pvalue;
716					/* LINTED */
717					name = pname;
718					/* LINTED */
719					symdef = psymdef;
720					/* LINTED */
721					symref = psymref;
722					/* LINTED */
723					_lmp = plmp;
724					/* LINTED */
725					binfo = pbinfo;
726
727					if ((LIST(_lmp)->lm_tflags |
728					    FLAGS1(_lmp)) &
729					    LML_TFLG_AUD_SYMBIND) {
730						value = audit_symbind(lmp, _lmp,
731						    /* LINTED */
732						    symdef, dsymndx, value,
733						    &sb_flags);
734					}
735				} else {
736					Slookup		sl;
737
738					/*
739					 * Lookup the symbol definition.
740					 * Initialize the symbol lookup data
741					 * structure.
742					 */
743					name = (char *)(STRTAB(lmp) +
744					    symref->st_name);
745
746					SLOOKUP_INIT(sl, name, lmp, 0,
747					    ld_entry_cnt, 0, rsymndx, symref,
748					    rtype, LKUP_STDRELOC);
749
750					symdef = lookup_sym(&sl, &_lmp, &binfo);
751
752					/*
753					 * If the symbol is not found and the
754					 * reference was not to a weak symbol,
755					 * report an error.  Weak references
756					 * may be unresolved.
757					 */
758					/* BEGIN CSTYLED */
759					if (symdef == 0) {
760					    if (sl.sl_bind != STB_WEAK) {
761						if (elf_reloc_error(lmp, name,
762						    rel, binfo))
763							continue;
764
765						ret = 0;
766						break;
767
768					    } else {
769						psymndx = rsymndx;
770						psymdef = 0;
771
772						DBG_CALL(Dbg_bind_weak(lmp,
773						    (Addr)roffset, (Addr)
774						    (roffset - basebgn), name));
775						continue;
776					    }
777					}
778					/* END CSTYLED */
779
780					/*
781					 * If symbol was found in an object
782					 * other than the referencing object
783					 * then record the binding.
784					 */
785					if ((lmp != _lmp) && ((FLAGS1(_lmp) &
786					    FL1_RT_NOINIFIN) == 0)) {
787						if (aplist_test(&bound, _lmp,
788						    AL_CNT_RELBIND) == 0) {
789							ret = 0;
790							break;
791						}
792					}
793
794					/*
795					 * Calculate the location of definition;
796					 * symbol value plus base address of
797					 * containing shared object.
798					 */
799					if (IS_SIZE(rtype))
800						value = symdef->st_size;
801					else
802						value = symdef->st_value;
803
804					if (!(FLAGS(_lmp) & FLG_RT_FIXED) &&
805					    !(IS_SIZE(rtype)) &&
806					    (symdef->st_shndx != SHN_ABS) &&
807					    (ELF_ST_TYPE(symdef->st_info) !=
808					    STT_TLS))
809						value += ADDR(_lmp);
810
811					/*
812					 * Retain this symbol index and the
813					 * value in case it can be used for the
814					 * subsequent relocations.
815					 */
816					if (rtype != R_386_COPY) {
817						psymndx = rsymndx;
818						pvalue = value;
819						pname = name;
820						psymdef = symdef;
821						psymref = symref;
822						plmp = _lmp;
823						pbinfo = binfo;
824					}
825					if ((LIST(_lmp)->lm_tflags |
826					    FLAGS1(_lmp)) &
827					    LML_TFLG_AUD_SYMBIND) {
828						dsymndx = (((uintptr_t)symdef -
829						    (uintptr_t)SYMTAB(_lmp)) /
830						    SYMENT(_lmp));
831						value = audit_symbind(lmp, _lmp,
832						    symdef, dsymndx, value,
833						    &sb_flags);
834					}
835				}
836
837				/*
838				 * If relocation is PC-relative, subtract
839				 * offset address.
840				 */
841				if (IS_PC_RELATIVE(rtype))
842					value -= roffset;
843
844				/*
845				 * Special case TLS relocations.
846				 */
847				if (rtype == R_386_TLS_DTPMOD32) {
848					/*
849					 * Relocation value is the TLS modid.
850					 */
851					value = TLSMODID(_lmp);
852
853				} else if (rtype == R_386_TLS_TPOFF) {
854					if ((value = elf_static_tls(_lmp,
855					    symdef, rel, rtype, name, roffset,
856					    value)) == 0) {
857						ret = 0;
858						break;
859					}
860				}
861			}
862		} else {
863			/*
864			 * Special cases.
865			 */
866			if (rtype == R_386_TLS_DTPMOD32) {
867				/*
868				 * TLS relocation value is the TLS modid.
869				 */
870				value = TLSMODID(lmp);
871			} else
872				value = basebgn;
873			name = (char *)0;
874		}
875
876		DBG_CALL(Dbg_reloc_in(LIST(lmp), ELF_DBG_RTLD, M_MACH,
877		    M_REL_SHT_TYPE, rel, NULL, name));
878
879		/*
880		 * If this object has relocations in the text segment, turn
881		 * off the write protect.
882		 */
883		if ((roffset < etext) && (textrel == 0)) {
884			if (elf_set_prot(lmp, PROT_WRITE) == 0) {
885				ret = 0;
886				break;
887			}
888			textrel = 1;
889		}
890
891		/*
892		 * Call relocation routine to perform required relocation.
893		 */
894		switch (rtype) {
895		case R_386_COPY:
896			if (elf_copy_reloc(name, symref, lmp, (void *)roffset,
897			    symdef, _lmp, (const void *)value) == 0)
898				ret = 0;
899			break;
900		case R_386_JMP_SLOT:
901			if (((LIST(lmp)->lm_tflags | FLAGS1(lmp)) &
902			    (LML_TFLG_AUD_PLTENTER | LML_TFLG_AUD_PLTEXIT)) &&
903			    AUDINFO(lmp)->ai_dynplts) {
904				int	fail = 0;
905				int	pltndx = (((ulong_t)rel -
906				    (uintptr_t)JMPREL(lmp)) / relsiz);
907				int	symndx = (((uintptr_t)symdef -
908				    (uintptr_t)SYMTAB(_lmp)) / SYMENT(_lmp));
909
910				(void) elf_plt_trace_write(roffset, lmp, _lmp,
911				    symdef, symndx, pltndx, (caddr_t)value,
912				    sb_flags, &fail);
913				if (fail)
914					ret = 0;
915			} else {
916				/*
917				 * Write standard PLT entry to jump directly
918				 * to newly bound function.
919				 */
920				DBG_CALL(Dbg_reloc_apply_val(LIST(lmp),
921				    ELF_DBG_RTLD, (Xword)roffset,
922				    (Xword)value));
923				*(ulong_t *)roffset = value;
924			}
925			break;
926		default:
927			/*
928			 * Write the relocation out.
929			 */
930			if (do_reloc_rtld(rtype, (uchar_t *)roffset,
931			    (Word *)&value, name, NAME(lmp), LIST(lmp)) == 0)
932				ret = 0;
933
934			DBG_CALL(Dbg_reloc_apply_val(LIST(lmp), ELF_DBG_RTLD,
935			    (Xword)roffset, (Xword)value));
936		}
937
938		if ((ret == 0) &&
939		    ((LIST(lmp)->lm_flags & LML_FLG_TRC_WARN) == 0))
940			break;
941
942		if (binfo) {
943			DBG_CALL(Dbg_bind_global(lmp, (Addr)roffset,
944			    (Off)(roffset - basebgn), (Xword)(-1), PLT_T_FULL,
945			    _lmp, (Addr)value, symdef->st_value, name, binfo));
946		}
947	}
948
949	return (relocate_finish(lmp, bound, textrel, ret));
950}
951
952/*
953 * Initialize the first few got entries so that function calls go to
954 * elf_rtbndr:
955 *
956 *	GOT[GOT_XLINKMAP] =	the address of the link map
957 *	GOT[GOT_XRTLD] =	the address of rtbinder
958 */
959void
960elf_plt_init(void *got, caddr_t l)
961{
962	uint_t		*_got;
963	/* LINTED */
964	Rt_map		*lmp = (Rt_map *)l;
965
966	_got = (uint_t *)got + M_GOT_XLINKMAP;
967	*_got = (uint_t)lmp;
968	_got = (uint_t *)got + M_GOT_XRTLD;
969	*_got = (uint_t)elf_rtbndr;
970}
971
972/*
973 * For SVR4 Intel compatability.  USL uses /usr/lib/libc.so.1 as the run-time
974 * linker, so the interpreter's address will differ from /usr/lib/ld.so.1.
975 * Further, USL has special _iob[] and _ctype[] processing that makes up for the
976 * fact that these arrays do not have associated copy relocations.  So we try
977 * and make up for that here.  Any relocations found will be added to the global
978 * copy relocation list and will be processed in setup().
979 */
980static int
981_elf_copy_reloc(const char *name, Rt_map *rlmp, Rt_map *dlmp)
982{
983	Sym		*symref, *symdef;
984	caddr_t 	ref, def;
985	Rt_map		*_lmp;
986	Rel		rel;
987	Slookup		sl;
988	uint_t		binfo;
989
990	/*
991	 * Determine if the special symbol exists as a reference in the dynamic
992	 * executable, and that an associated definition exists in libc.so.1.
993	 *
994	 * Initialize the symbol lookup data structure.
995	 */
996	SLOOKUP_INIT(sl, name, rlmp, rlmp, ld_entry_cnt, 0, 0, 0, 0,
997	    LKUP_FIRST);
998
999	if ((symref = lookup_sym(&sl, &_lmp, &binfo)) == 0)
1000		return (1);
1001
1002	sl.sl_imap = dlmp;
1003	sl.sl_flags = LKUP_DEFT;
1004
1005	if ((symdef = lookup_sym(&sl, &_lmp, &binfo)) == 0)
1006		return (1);
1007	if (strcmp(NAME(_lmp), MSG_ORIG(MSG_PTH_LIBC)))
1008		return (1);
1009
1010	/*
1011	 * Determine the reference and definition addresses.
1012	 */
1013	ref = (void *)(symref->st_value);
1014	if (!(FLAGS(rlmp) & FLG_RT_FIXED))
1015		ref += ADDR(rlmp);
1016	def = (void *)(symdef->st_value);
1017	if (!(FLAGS(_lmp) & FLG_RT_FIXED))
1018		def += ADDR(_lmp);
1019
1020	/*
1021	 * Set up a relocation entry for debugging and call the generic copy
1022	 * relocation function to provide symbol size error checking and to
1023	 * record the copy relocation that must be performed.
1024	 */
1025	rel.r_offset = (Addr)ref;
1026	rel.r_info = (Word)R_386_COPY;
1027	DBG_CALL(Dbg_reloc_in(LIST(rlmp), ELF_DBG_RTLD, M_MACH, M_REL_SHT_TYPE,
1028	    &rel, NULL, name));
1029
1030	return (elf_copy_reloc((char *)name, symref, rlmp, (void *)ref, symdef,
1031	    _lmp, (void *)def));
1032}
1033
1034int
1035elf_copy_gen(Rt_map *lmp)
1036{
1037	if (interp && ((ulong_t)interp->i_faddr !=
1038	    r_debug.rtd_rdebug.r_ldbase) &&
1039	    !(strcmp(interp->i_name, MSG_ORIG(MSG_PTH_LIBC)))) {
1040
1041		DBG_CALL(Dbg_reloc_run(lmp, M_REL_SHT_TYPE, 0,
1042		    DBG_REL_START));
1043
1044		if (_elf_copy_reloc(MSG_ORIG(MSG_SYM_CTYPE), lmp,
1045		    (Rt_map *)NEXT(lmp)) == 0)
1046			return (0);
1047		if (_elf_copy_reloc(MSG_ORIG(MSG_SYM_IOB), lmp,
1048		    (Rt_map *)NEXT(lmp)) == 0)
1049			return (0);
1050	}
1051	return (1);
1052}
1053
1054/*
1055 * Plt writing interface to allow debugging initialization to be generic.
1056 */
1057Pltbindtype
1058/* ARGSUSED1 */
1059elf_plt_write(uintptr_t addr, uintptr_t vaddr, void *rptr, uintptr_t symval,
1060	Xword pltndx)
1061{
1062	Rel		*rel = (Rel*)rptr;
1063	uintptr_t	pltaddr;
1064
1065	pltaddr = addr + rel->r_offset;
1066	*(ulong_t *)pltaddr = (ulong_t)symval;
1067	DBG_CALL(pltcntfull++);
1068	return (PLT_T_FULL);
1069}
1070
1071/*
1072 * Provide a machine specific interface to the conversion routine.  By calling
1073 * the machine specific version, rather than the generic version, we insure that
1074 * the data tables/strings for all known machine versions aren't dragged into
1075 * ld.so.1.
1076 */
1077const char *
1078_conv_reloc_type(uint_t rel)
1079{
1080	static Conv_inv_buf_t inv_buf;
1081
1082	return (conv_reloc_386_type(rel, 0, &inv_buf));
1083}
1084