xref: /freebsd/sys/kern/link_elf.c (revision a2024a3edff86b418e3e599ee5db65a7e653605d)
1 /*-
2  * Copyright (c) 1998-2000 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_ddb.h"
31 #include "opt_gdb.h"
32 #include "opt_mac.h"
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #ifdef GPROF
37 #include <sys/gmon.h>
38 #endif
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mutex.h>
43 #include <sys/mount.h>
44 #include <sys/proc.h>
45 #include <sys/namei.h>
46 #include <sys/fcntl.h>
47 #include <sys/vnode.h>
48 #include <sys/linker.h>
49 
50 #include <machine/elf.h>
51 
52 #include <security/mac/mac_framework.h>
53 
54 #include <vm/vm.h>
55 #include <vm/vm_param.h>
56 #ifdef SPARSE_MAPPING
57 #include <vm/vm_object.h>
58 #include <vm/vm_kern.h>
59 #include <vm/vm_extern.h>
60 #endif
61 #include <vm/pmap.h>
62 #include <vm/vm_map.h>
63 
64 #include <sys/link_elf.h>
65 
66 #ifdef DDB_CTF
67 #include <net/zlib.h>
68 #endif
69 
70 #include "linker_if.h"
71 
72 #define MAXSEGS 4
73 
74 typedef struct elf_file {
75     struct linker_file	lf;		/* Common fields */
76     int			preloaded;	/* Was file pre-loaded */
77     caddr_t		address;	/* Relocation address */
78 #ifdef SPARSE_MAPPING
79     vm_object_t		object;		/* VM object to hold file pages */
80 #endif
81     Elf_Dyn*		dynamic;	/* Symbol table etc. */
82     Elf_Hashelt		nbuckets;	/* DT_HASH info */
83     Elf_Hashelt		nchains;
84     const Elf_Hashelt*	buckets;
85     const Elf_Hashelt*	chains;
86     caddr_t		hash;
87     caddr_t		strtab;		/* DT_STRTAB */
88     int			strsz;		/* DT_STRSZ */
89     const Elf_Sym*	symtab;		/* DT_SYMTAB */
90     Elf_Addr*		got;		/* DT_PLTGOT */
91     const Elf_Rel*	pltrel;		/* DT_JMPREL */
92     int			pltrelsize;	/* DT_PLTRELSZ */
93     const Elf_Rela*	pltrela;	/* DT_JMPREL */
94     int			pltrelasize;	/* DT_PLTRELSZ */
95     const Elf_Rel*	rel;		/* DT_REL */
96     int			relsize;	/* DT_RELSZ */
97     const Elf_Rela*	rela;		/* DT_RELA */
98     int			relasize;	/* DT_RELASZ */
99     caddr_t		modptr;
100     const Elf_Sym*	ddbsymtab;	/* The symbol table we are using */
101     long		ddbsymcnt;	/* Number of symbols */
102     caddr_t		ddbstrtab;	/* String table */
103     long		ddbstrcnt;	/* number of bytes in string table */
104     caddr_t		symbase;	/* malloc'ed symbold base */
105     caddr_t		strbase;	/* malloc'ed string base */
106     caddr_t		ctftab;		/* CTF table */
107     long		ctfcnt;		/* number of bytes in CTF table */
108     caddr_t		ctfoff;		/* CTF offset table */
109     caddr_t		typoff;		/* Type offset table */
110     long		typlen;		/* Number of type entries. */
111 #ifdef GDB
112     struct link_map	gdb;		/* hooks for gdb */
113 #endif
114 } *elf_file_t;
115 
116 #include <kern/kern_ctf.c>
117 
118 static int	link_elf_link_common_finish(linker_file_t);
119 static int	link_elf_link_preload(linker_class_t cls,
120 				      const char*, linker_file_t*);
121 static int	link_elf_link_preload_finish(linker_file_t);
122 static int	link_elf_load_file(linker_class_t, const char*, linker_file_t*);
123 static int	link_elf_lookup_symbol(linker_file_t, const char*,
124 				       c_linker_sym_t*);
125 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
126 static int	link_elf_search_symbol(linker_file_t, caddr_t value,
127 				       c_linker_sym_t* sym, long* diffp);
128 
129 static void	link_elf_unload_file(linker_file_t);
130 static void	link_elf_unload_preload(linker_file_t);
131 static int	link_elf_lookup_set(linker_file_t, const char *,
132 				    void ***, void ***, int *);
133 static int	link_elf_each_function_name(linker_file_t,
134 				int (*)(const char *, void *),
135 				void *);
136 static int	link_elf_each_function_nameval(linker_file_t,
137 				linker_function_nameval_callback_t,
138 				void *);
139 static void	link_elf_reloc_local(linker_file_t);
140 static Elf_Addr	elf_lookup(linker_file_t lf, Elf_Size symidx, int deps);
141 
142 static kobj_method_t link_elf_methods[] = {
143     KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
144     KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
145     KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
146     KOBJMETHOD(linker_unload,		link_elf_unload_file),
147     KOBJMETHOD(linker_load_file,	link_elf_load_file),
148     KOBJMETHOD(linker_link_preload,	link_elf_link_preload),
149     KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
150     KOBJMETHOD(linker_lookup_set,	link_elf_lookup_set),
151     KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
152     KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
153     KOBJMETHOD(linker_ctf_get,          link_elf_ctf_get),
154     { 0, 0 }
155 };
156 
157 static struct linker_class link_elf_class = {
158 #if ELF_TARG_CLASS == ELFCLASS32
159     "elf32",
160 #else
161     "elf64",
162 #endif
163     link_elf_methods, sizeof(struct elf_file)
164 };
165 
166 static int		parse_dynamic(elf_file_t ef);
167 static int		relocate_file(elf_file_t ef);
168 static int		link_elf_preload_parse_symbols(elf_file_t ef);
169 
170 #ifdef GDB
171 static void		r_debug_state(struct r_debug *dummy_one,
172 				      struct link_map *dummy_two);
173 
174 /*
175  * A list of loaded modules for GDB to use for loading symbols.
176  */
177 struct r_debug r_debug;
178 
179 #define GDB_STATE(s)	r_debug.r_state = s; r_debug_state(NULL, NULL);
180 
181 /*
182  * Function for the debugger to set a breakpoint on to gain control.
183  */
184 static void
185 r_debug_state(struct r_debug *dummy_one __unused,
186 	      struct link_map *dummy_two __unused)
187 {
188 }
189 
190 static void
191 link_elf_add_gdb(struct link_map *l)
192 {
193     struct link_map *prev;
194 
195     l->l_next = NULL;
196 
197     if (r_debug.r_map == NULL) {
198 	/* Add first. */
199 	l->l_prev = NULL;
200 	r_debug.r_map = l;
201     } else {
202 	/* Append to list. */
203 	for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
204 	    ;
205 	l->l_prev = prev;
206 	prev->l_next = l;
207     }
208 }
209 
210 static void
211 link_elf_delete_gdb(struct link_map *l)
212 {
213     if (l->l_prev == NULL) {
214 	/* Remove first. */
215 	if ((r_debug.r_map = l->l_next) != NULL)
216 	    l->l_next->l_prev = NULL;
217     } else {
218 	/* Remove any but first. */
219 	if ((l->l_prev->l_next = l->l_next) != NULL)
220 	    l->l_next->l_prev = l->l_prev;
221     }
222 }
223 #endif /* GDB */
224 
225 #ifdef __ia64__
226 Elf_Addr link_elf_get_gp(linker_file_t);
227 #endif
228 
229 /*
230  * The kernel symbol table starts here.
231  */
232 extern struct _dynamic _DYNAMIC;
233 
234 static void
235 link_elf_error(const char *s)
236 {
237     printf("kldload: %s\n", s);
238 }
239 
240 /*
241  * Actions performed after linking/loading both the preloaded kernel and any
242  * modules; whether preloaded or dynamicly loaded.
243  */
244 static int
245 link_elf_link_common_finish(linker_file_t lf)
246 {
247 #ifdef GDB
248     elf_file_t ef = (elf_file_t)lf;
249     char *newfilename;
250 #endif
251     int error;
252 
253     /* Notify MD code that a module is being loaded. */
254     error = elf_cpu_load_file(lf);
255     if (error)
256 	return (error);
257 
258 #ifdef GDB
259     GDB_STATE(RT_ADD);
260     ef->gdb.l_addr = lf->address;
261     newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
262     strcpy(newfilename, lf->filename);
263     ef->gdb.l_name = newfilename;
264     ef->gdb.l_ld = ef->dynamic;
265     link_elf_add_gdb(&ef->gdb);
266     GDB_STATE(RT_CONSISTENT);
267 #endif
268 
269     return (0);
270 }
271 
272 static void
273 link_elf_init(void* arg)
274 {
275     Elf_Dyn	*dp;
276     caddr_t	modptr, baseptr, sizeptr;
277     elf_file_t	ef;
278     char	*modname;
279 
280     linker_add_class(&link_elf_class);
281 
282     dp = (Elf_Dyn*) &_DYNAMIC;
283     modname = NULL;
284     modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
285     if (modptr == NULL)
286 	modptr = preload_search_by_type("elf kernel");
287     if (modptr)
288 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
289     if (modname == NULL)
290 	modname = "kernel";
291     linker_kernel_file = linker_make_file(modname, &link_elf_class);
292     if (linker_kernel_file == NULL)
293 	panic("link_elf_init: Can't create linker structures for kernel");
294 
295     ef = (elf_file_t) linker_kernel_file;
296     ef->preloaded = 1;
297     ef->address = 0;
298 #ifdef SPARSE_MAPPING
299     ef->object = 0;
300 #endif
301     ef->dynamic = dp;
302 
303     if (dp)
304 	parse_dynamic(ef);
305     linker_kernel_file->address = (caddr_t) KERNBASE;
306     linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
307 
308     if (modptr) {
309 	ef->modptr = modptr;
310 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
311 	if (baseptr)
312 	    linker_kernel_file->address = *(caddr_t *)baseptr;
313 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
314 	if (sizeptr)
315 	    linker_kernel_file->size = *(size_t *)sizeptr;
316     }
317     (void)link_elf_preload_parse_symbols(ef);
318 
319 #ifdef GDB
320     r_debug.r_map = NULL;
321     r_debug.r_brk = r_debug_state;
322     r_debug.r_state = RT_CONSISTENT;
323 #endif
324 
325     (void)link_elf_link_common_finish(linker_kernel_file);
326     linker_kernel_file->flags |= LINKER_FILE_LINKED;
327 }
328 
329 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
330 
331 static int
332 link_elf_preload_parse_symbols(elf_file_t ef)
333 {
334     caddr_t	pointer;
335     caddr_t	ssym, esym, base;
336     caddr_t	strtab;
337     int		strcnt;
338     Elf_Sym*	symtab;
339     int		symcnt;
340 
341     if (ef->modptr == NULL)
342 	return 0;
343     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
344     if (pointer == NULL)
345 	return 0;
346     ssym = *(caddr_t *)pointer;
347     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
348     if (pointer == NULL)
349 	return 0;
350     esym = *(caddr_t *)pointer;
351 
352     base = ssym;
353 
354     symcnt = *(long *)base;
355     base += sizeof(long);
356     symtab = (Elf_Sym *)base;
357     base += roundup(symcnt, sizeof(long));
358 
359     if (base > esym || base < ssym) {
360 	printf("Symbols are corrupt!\n");
361 	return EINVAL;
362     }
363 
364     strcnt = *(long *)base;
365     base += sizeof(long);
366     strtab = base;
367     base += roundup(strcnt, sizeof(long));
368 
369     if (base > esym || base < ssym) {
370 	printf("Symbols are corrupt!\n");
371 	return EINVAL;
372     }
373 
374     ef->ddbsymtab = symtab;
375     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
376     ef->ddbstrtab = strtab;
377     ef->ddbstrcnt = strcnt;
378 
379     return 0;
380 }
381 
382 static int
383 parse_dynamic(elf_file_t ef)
384 {
385     Elf_Dyn *dp;
386     int plttype = DT_REL;
387 
388     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
389 	switch (dp->d_tag) {
390 	case DT_HASH:
391 	{
392 	    /* From src/libexec/rtld-elf/rtld.c */
393 	    const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
394 		(ef->address + dp->d_un.d_ptr);
395 	    ef->nbuckets = hashtab[0];
396 	    ef->nchains = hashtab[1];
397 	    ef->buckets = hashtab + 2;
398 	    ef->chains = ef->buckets + ef->nbuckets;
399 	    break;
400 	}
401 	case DT_STRTAB:
402 	    ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
403 	    break;
404 	case DT_STRSZ:
405 	    ef->strsz = dp->d_un.d_val;
406 	    break;
407 	case DT_SYMTAB:
408 	    ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
409 	    break;
410 	case DT_SYMENT:
411 	    if (dp->d_un.d_val != sizeof(Elf_Sym))
412 		return ENOEXEC;
413 	    break;
414 	case DT_PLTGOT:
415 	    ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
416 	    break;
417 	case DT_REL:
418 	    ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
419 	    break;
420 	case DT_RELSZ:
421 	    ef->relsize = dp->d_un.d_val;
422 	    break;
423 	case DT_RELENT:
424 	    if (dp->d_un.d_val != sizeof(Elf_Rel))
425 		return ENOEXEC;
426 	    break;
427 	case DT_JMPREL:
428 	    ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
429 	    break;
430 	case DT_PLTRELSZ:
431 	    ef->pltrelsize = dp->d_un.d_val;
432 	    break;
433 	case DT_RELA:
434 	    ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
435 	    break;
436 	case DT_RELASZ:
437 	    ef->relasize = dp->d_un.d_val;
438 	    break;
439 	case DT_RELAENT:
440 	    if (dp->d_un.d_val != sizeof(Elf_Rela))
441 		return ENOEXEC;
442 	    break;
443 	case DT_PLTREL:
444 	    plttype = dp->d_un.d_val;
445 	    if (plttype != DT_REL && plttype != DT_RELA)
446 		return ENOEXEC;
447 	    break;
448 #ifdef GDB
449 	case DT_DEBUG:
450 	    dp->d_un.d_ptr = (Elf_Addr) &r_debug;
451 	    break;
452 #endif
453 	}
454     }
455 
456     if (plttype == DT_RELA) {
457 	ef->pltrela = (const Elf_Rela *) ef->pltrel;
458 	ef->pltrel = NULL;
459 	ef->pltrelasize = ef->pltrelsize;
460 	ef->pltrelsize = 0;
461     }
462 
463     ef->ddbsymtab = ef->symtab;
464     ef->ddbsymcnt = ef->nchains;
465     ef->ddbstrtab = ef->strtab;
466     ef->ddbstrcnt = ef->strsz;
467 
468     return 0;
469 }
470 
471 static int
472 link_elf_link_preload(linker_class_t cls,
473 		      const char* filename, linker_file_t *result)
474 {
475     caddr_t		modptr, baseptr, sizeptr, dynptr;
476     char		*type;
477     elf_file_t		ef;
478     linker_file_t	lf;
479     int			error;
480     vm_offset_t		dp;
481 
482     /* Look to see if we have the file preloaded */
483     modptr = preload_search_by_name(filename);
484     if (modptr == NULL)
485 	return ENOENT;
486 
487     type = (char *)preload_search_info(modptr, MODINFO_TYPE);
488     baseptr = preload_search_info(modptr, MODINFO_ADDR);
489     sizeptr = preload_search_info(modptr, MODINFO_SIZE);
490     dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
491     if (type == NULL ||
492 	(strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
493 	 strcmp(type, "elf module") != 0))
494 	return (EFTYPE);
495     if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
496 	return (EINVAL);
497 
498     lf = linker_make_file(filename, &link_elf_class);
499     if (lf == NULL) {
500 	return ENOMEM;
501     }
502 
503     ef = (elf_file_t) lf;
504     ef->preloaded = 1;
505     ef->modptr = modptr;
506     ef->address = *(caddr_t *)baseptr;
507 #ifdef SPARSE_MAPPING
508     ef->object = 0;
509 #endif
510     dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
511     ef->dynamic = (Elf_Dyn *)dp;
512     lf->address = ef->address;
513     lf->size = *(size_t *)sizeptr;
514 
515     error = parse_dynamic(ef);
516     if (error) {
517 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
518 	return error;
519     }
520     link_elf_reloc_local(lf);
521     *result = lf;
522     return (0);
523 }
524 
525 static int
526 link_elf_link_preload_finish(linker_file_t lf)
527 {
528     elf_file_t		ef;
529     int error;
530 
531     ef = (elf_file_t) lf;
532 #if 0	/* this will be more trouble than it's worth for now */
533     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
534 	if (dp->d_tag != DT_NEEDED)
535 	    continue;
536 	modname = ef->strtab + dp->d_un.d_val;
537 	error = linker_load_module(modname, lf);
538 	if (error)
539 	    goto out;
540     }
541 #endif
542     error = relocate_file(ef);
543     if (error)
544 	return error;
545     (void)link_elf_preload_parse_symbols(ef);
546 
547     return (link_elf_link_common_finish(lf));
548 }
549 
550 static int
551 link_elf_load_file(linker_class_t cls, const char* filename,
552 	linker_file_t* result)
553 {
554     struct nameidata nd;
555     struct thread* td = curthread;	/* XXX */
556     Elf_Ehdr *hdr;
557     caddr_t firstpage;
558     int nbytes, i;
559     Elf_Phdr *phdr;
560     Elf_Phdr *phlimit;
561     Elf_Phdr *segs[MAXSEGS];
562     int nsegs;
563     Elf_Phdr *phdyn;
564     Elf_Phdr *phphdr;
565     caddr_t mapbase;
566     size_t mapsize;
567     Elf_Off base_offset;
568     Elf_Addr base_vaddr;
569     Elf_Addr base_vlimit;
570     int error = 0;
571     int resid, flags;
572     elf_file_t ef;
573     linker_file_t lf;
574     Elf_Shdr *shdr;
575     int symtabindex;
576     int symstrindex;
577     int symcnt;
578     int strcnt;
579     int vfslocked;
580 
581     shdr = NULL;
582     lf = NULL;
583 
584     NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
585     flags = FREAD;
586     error = vn_open(&nd, &flags, 0, NULL);
587     if (error)
588 	return error;
589     vfslocked = NDHASGIANT(&nd);
590     NDFREE(&nd, NDF_ONLY_PNBUF);
591     if (nd.ni_vp->v_type != VREG) {
592 	error = ENOEXEC;
593 	firstpage = NULL;
594 	goto out;
595     }
596 #ifdef MAC
597     error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
598     if (error) {
599 	firstpage = NULL;
600 	goto out;
601     }
602 #endif
603 
604     /*
605      * Read the elf header from the file.
606      */
607     firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
608     if (firstpage == NULL) {
609 	error = ENOMEM;
610 	goto out;
611     }
612     hdr = (Elf_Ehdr *)firstpage;
613     error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
614 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
615 		    &resid, td);
616     nbytes = PAGE_SIZE - resid;
617     if (error)
618 	goto out;
619 
620     if (!IS_ELF(*hdr)) {
621 	error = ENOEXEC;
622 	goto out;
623     }
624 
625     if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
626       || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
627 	link_elf_error("Unsupported file layout");
628 	error = ENOEXEC;
629 	goto out;
630     }
631     if (hdr->e_ident[EI_VERSION] != EV_CURRENT
632       || hdr->e_version != EV_CURRENT) {
633 	link_elf_error("Unsupported file version");
634 	error = ENOEXEC;
635 	goto out;
636     }
637     if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
638 	link_elf_error("Unsupported file type");
639 	error = ENOEXEC;
640 	goto out;
641     }
642     if (hdr->e_machine != ELF_TARG_MACH) {
643 	link_elf_error("Unsupported machine");
644 	error = ENOEXEC;
645 	goto out;
646     }
647 
648     /*
649      * We rely on the program header being in the first page.  This is
650      * not strictly required by the ABI specification, but it seems to
651      * always true in practice.  And, it simplifies things considerably.
652      */
653     if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
654 	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
655 	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
656 	link_elf_error("Unreadable program headers");
657 
658     /*
659      * Scan the program header entries, and save key information.
660      *
661      * We rely on there being exactly two load segments, text and data,
662      * in that order.
663      */
664     phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
665     phlimit = phdr + hdr->e_phnum;
666     nsegs = 0;
667     phdyn = NULL;
668     phphdr = NULL;
669     while (phdr < phlimit) {
670 	switch (phdr->p_type) {
671 
672 	case PT_LOAD:
673 	    if (nsegs == MAXSEGS) {
674 		link_elf_error("Too many sections");
675 		error = ENOEXEC;
676 		goto out;
677 	    }
678 	    /*
679 	     * XXX: We just trust they come in right order ??
680 	     */
681 	    segs[nsegs] = phdr;
682 	    ++nsegs;
683 	    break;
684 
685 	case PT_PHDR:
686 	    phphdr = phdr;
687 	    break;
688 
689 	case PT_DYNAMIC:
690 	    phdyn = phdr;
691 	    break;
692 
693 	case PT_INTERP:
694 	    link_elf_error("Unsupported file type");
695 	    error = ENOEXEC;
696 	    goto out;
697 	}
698 
699 	++phdr;
700     }
701     if (phdyn == NULL) {
702 	link_elf_error("Object is not dynamically-linked");
703 	error = ENOEXEC;
704 	goto out;
705     }
706     if (nsegs == 0) {
707 	link_elf_error("No sections");
708 	error = ENOEXEC;
709 	goto out;
710     }
711 
712     /*
713      * Allocate the entire address space of the object, to stake out our
714      * contiguous region, and to establish the base address for relocation.
715      */
716     base_offset = trunc_page(segs[0]->p_offset);
717     base_vaddr = trunc_page(segs[0]->p_vaddr);
718     base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
719 	segs[nsegs - 1]->p_memsz);
720     mapsize = base_vlimit - base_vaddr;
721 
722     lf = linker_make_file(filename, &link_elf_class);
723     if (!lf) {
724 	error = ENOMEM;
725 	goto out;
726     }
727 
728     ef = (elf_file_t) lf;
729 #ifdef SPARSE_MAPPING
730     ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
731     if (ef->object == NULL) {
732 	error = ENOMEM;
733 	goto out;
734     }
735     ef->address = (caddr_t) vm_map_min(kernel_map);
736     error = vm_map_find(kernel_map, ef->object, 0,
737 			(vm_offset_t *) &ef->address,
738 			mapsize, 1,
739 			VM_PROT_ALL, VM_PROT_ALL, 0);
740     if (error) {
741 	vm_object_deallocate(ef->object);
742 	ef->object = 0;
743 	goto out;
744     }
745 #else
746     ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
747     if (!ef->address) {
748 	error = ENOMEM;
749 	goto out;
750     }
751 #endif
752     mapbase = ef->address;
753 
754     /*
755      * Read the text and data sections and zero the bss.
756      */
757     for (i = 0; i < nsegs; i++) {
758 	caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
759 	error = vn_rdwr(UIO_READ, nd.ni_vp,
760 			segbase, segs[i]->p_filesz, segs[i]->p_offset,
761 			UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
762 			&resid, td);
763 	if (error) {
764 	    goto out;
765 	}
766 	bzero(segbase + segs[i]->p_filesz,
767 	      segs[i]->p_memsz - segs[i]->p_filesz);
768 
769 #ifdef SPARSE_MAPPING
770 	/*
771 	 * Wire down the pages
772 	 */
773 	error = vm_map_wire(kernel_map,
774 		    (vm_offset_t) segbase,
775 		    (vm_offset_t) segbase + segs[i]->p_memsz,
776 		    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
777 	if (error != KERN_SUCCESS) {
778 	    error = ENOMEM;
779 	    goto out;
780 	}
781 #endif
782     }
783 
784 #ifdef GPROF
785     /* Update profiling information with the new text segment. */
786     mtx_lock(&Giant);
787     kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
788 	segs[0]->p_memsz));
789     mtx_unlock(&Giant);
790 #endif
791 
792     ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
793 
794     lf->address = ef->address;
795     lf->size = mapsize;
796 
797     error = parse_dynamic(ef);
798     if (error)
799 	goto out;
800     link_elf_reloc_local(lf);
801 
802     error = linker_load_dependencies(lf);
803     if (error)
804 	goto out;
805 #if 0	/* this will be more trouble than it's worth for now */
806     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
807 	if (dp->d_tag != DT_NEEDED)
808 	    continue;
809 	modname = ef->strtab + dp->d_un.d_val;
810 	error = linker_load_module(modname, lf);
811 	if (error)
812 	    goto out;
813     }
814 #endif
815     error = relocate_file(ef);
816     if (error)
817 	goto out;
818 
819     /* Try and load the symbol table if it's present.  (you can strip it!) */
820     nbytes = hdr->e_shnum * hdr->e_shentsize;
821     if (nbytes == 0 || hdr->e_shoff == 0)
822 	goto nosyms;
823     shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
824     if (shdr == NULL) {
825 	error = ENOMEM;
826 	goto out;
827     }
828     error = vn_rdwr(UIO_READ, nd.ni_vp,
829 		    (caddr_t)shdr, nbytes, hdr->e_shoff,
830 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
831 		    &resid, td);
832     if (error)
833 	goto out;
834     symtabindex = -1;
835     symstrindex = -1;
836     for (i = 0; i < hdr->e_shnum; i++) {
837 	if (shdr[i].sh_type == SHT_SYMTAB) {
838 	    symtabindex = i;
839 	    symstrindex = shdr[i].sh_link;
840 	}
841     }
842     if (symtabindex < 0 || symstrindex < 0)
843 	goto nosyms;
844 
845     symcnt = shdr[symtabindex].sh_size;
846     ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
847     strcnt = shdr[symstrindex].sh_size;
848     ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
849 
850     if (ef->symbase == NULL || ef->strbase == NULL) {
851 	error = ENOMEM;
852 	goto out;
853     }
854     error = vn_rdwr(UIO_READ, nd.ni_vp,
855 		    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
856 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
857 		    &resid, td);
858     if (error)
859 	goto out;
860     error = vn_rdwr(UIO_READ, nd.ni_vp,
861 		    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
862 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
863 		    &resid, td);
864     if (error)
865 	goto out;
866 
867     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
868     ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
869     ef->ddbstrcnt = strcnt;
870     ef->ddbstrtab = ef->strbase;
871 
872     error = link_elf_link_common_finish(lf);
873     if (error)
874 	goto out;
875 
876 nosyms:
877 
878     *result = lf;
879 
880 out:
881     if (error && lf)
882 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
883     if (shdr)
884 	free(shdr, M_LINKER);
885     if (firstpage)
886 	free(firstpage, M_LINKER);
887     VOP_UNLOCK(nd.ni_vp, 0);
888     vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
889     VFS_UNLOCK_GIANT(vfslocked);
890 
891     return error;
892 }
893 
894 static void
895 link_elf_unload_file(linker_file_t file)
896 {
897     elf_file_t ef = (elf_file_t) file;
898 
899 #ifdef GDB
900     if (ef->gdb.l_ld) {
901 	GDB_STATE(RT_DELETE);
902 	free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
903 	link_elf_delete_gdb(&ef->gdb);
904 	GDB_STATE(RT_CONSISTENT);
905     }
906 #endif
907 
908     /* Notify MD code that a module is being unloaded. */
909     elf_cpu_unload_file(file);
910 
911     if (ef->preloaded) {
912 	link_elf_unload_preload(file);
913 	return;
914     }
915 
916 #ifdef SPARSE_MAPPING
917     if (ef->object) {
918 	vm_map_remove(kernel_map, (vm_offset_t) ef->address,
919 		      (vm_offset_t) ef->address
920 		      + (ef->object->size << PAGE_SHIFT));
921     }
922 #else
923     if (ef->address)
924 	free(ef->address, M_LINKER);
925 #endif
926     if (ef->symbase)
927 	free(ef->symbase, M_LINKER);
928     if (ef->strbase)
929 	free(ef->strbase, M_LINKER);
930     if (ef->ctftab)
931 	free(ef->ctftab, M_LINKER);
932     if (ef->ctfoff)
933 	free(ef->ctfoff, M_LINKER);
934     if (ef->typoff)
935 	free(ef->typoff, M_LINKER);
936 }
937 
938 static void
939 link_elf_unload_preload(linker_file_t file)
940 {
941     if (file->filename)
942 	preload_delete_name(file->filename);
943 }
944 
945 static const char *
946 symbol_name(elf_file_t ef, Elf_Size r_info)
947 {
948     const Elf_Sym *ref;
949 
950     if (ELF_R_SYM(r_info)) {
951 	ref = ef->symtab + ELF_R_SYM(r_info);
952 	return ef->strtab + ref->st_name;
953     } else
954 	return NULL;
955 }
956 
957 static int
958 relocate_file(elf_file_t ef)
959 {
960     const Elf_Rel *rellim;
961     const Elf_Rel *rel;
962     const Elf_Rela *relalim;
963     const Elf_Rela *rela;
964     const char *symname;
965 
966     /* Perform relocations without addend if there are any: */
967     rel = ef->rel;
968     if (rel) {
969 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
970 	while (rel < rellim) {
971 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
972 			  elf_lookup)) {
973 		symname = symbol_name(ef, rel->r_info);
974 		printf("link_elf: symbol %s undefined\n", symname);
975 		return ENOENT;
976 	    }
977 	    rel++;
978 	}
979     }
980 
981     /* Perform relocations with addend if there are any: */
982     rela = ef->rela;
983     if (rela) {
984 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
985 	while (rela < relalim) {
986 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
987 			  elf_lookup)) {
988 		symname = symbol_name(ef, rela->r_info);
989 		printf("link_elf: symbol %s undefined\n", symname);
990 		return ENOENT;
991 	    }
992 	    rela++;
993 	}
994     }
995 
996     /* Perform PLT relocations without addend if there are any: */
997     rel = ef->pltrel;
998     if (rel) {
999 	rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
1000 	while (rel < rellim) {
1001 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1002 			  elf_lookup)) {
1003 		symname = symbol_name(ef, rel->r_info);
1004 		printf("link_elf: symbol %s undefined\n", symname);
1005 		return ENOENT;
1006 	    }
1007 	    rel++;
1008 	}
1009     }
1010 
1011     /* Perform relocations with addend if there are any: */
1012     rela = ef->pltrela;
1013     if (rela) {
1014 	relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
1015 	while (rela < relalim) {
1016 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1017 			  elf_lookup)) {
1018 		symname = symbol_name(ef, rela->r_info);
1019 		printf("link_elf: symbol %s undefined\n", symname);
1020 		return ENOENT;
1021 	    }
1022 	    rela++;
1023 	}
1024     }
1025 
1026     return 0;
1027 }
1028 
1029 /*
1030  * Hash function for symbol table lookup.  Don't even think about changing
1031  * this.  It is specified by the System V ABI.
1032  */
1033 static unsigned long
1034 elf_hash(const char *name)
1035 {
1036     const unsigned char *p = (const unsigned char *) name;
1037     unsigned long h = 0;
1038     unsigned long g;
1039 
1040     while (*p != '\0') {
1041 	h = (h << 4) + *p++;
1042 	if ((g = h & 0xf0000000) != 0)
1043 	    h ^= g >> 24;
1044 	h &= ~g;
1045     }
1046     return h;
1047 }
1048 
1049 static int
1050 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1051 {
1052     elf_file_t ef = (elf_file_t) lf;
1053     unsigned long symnum;
1054     const Elf_Sym* symp;
1055     const char *strp;
1056     unsigned long hash;
1057     int i;
1058 
1059     /* If we don't have a hash, bail. */
1060     if (ef->buckets == NULL || ef->nbuckets == 0) {
1061 	printf("link_elf_lookup_symbol: missing symbol hash table\n");
1062 	return ENOENT;
1063     }
1064 
1065     /* First, search hashed global symbols */
1066     hash = elf_hash(name);
1067     symnum = ef->buckets[hash % ef->nbuckets];
1068 
1069     while (symnum != STN_UNDEF) {
1070 	if (symnum >= ef->nchains) {
1071 	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
1072 	    return ENOENT;
1073 	}
1074 
1075 	symp = ef->symtab + symnum;
1076 	if (symp->st_name == 0) {
1077 	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
1078 	    return ENOENT;
1079 	}
1080 
1081 	strp = ef->strtab + symp->st_name;
1082 
1083 	if (strcmp(name, strp) == 0) {
1084 	    if (symp->st_shndx != SHN_UNDEF ||
1085 		(symp->st_value != 0 &&
1086 		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1087 		*sym = (c_linker_sym_t) symp;
1088 		return 0;
1089 	    } else
1090 		return ENOENT;
1091 	}
1092 
1093 	symnum = ef->chains[symnum];
1094     }
1095 
1096     /* If we have not found it, look at the full table (if loaded) */
1097     if (ef->symtab == ef->ddbsymtab)
1098 	return ENOENT;
1099 
1100     /* Exhaustive search */
1101     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1102 	strp = ef->ddbstrtab + symp->st_name;
1103 	if (strcmp(name, strp) == 0) {
1104 	    if (symp->st_shndx != SHN_UNDEF ||
1105 		(symp->st_value != 0 &&
1106 		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1107 		*sym = (c_linker_sym_t) symp;
1108 		return 0;
1109 	    } else
1110 		return ENOENT;
1111 	}
1112     }
1113 
1114     return ENOENT;
1115 }
1116 
1117 static int
1118 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1119 {
1120 	elf_file_t ef = (elf_file_t) lf;
1121 	const Elf_Sym* es = (const Elf_Sym*) sym;
1122 
1123 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1124 	    symval->name = ef->strtab + es->st_name;
1125 	    symval->value = (caddr_t) ef->address + es->st_value;
1126 	    symval->size = es->st_size;
1127 	    return 0;
1128 	}
1129 	if (ef->symtab == ef->ddbsymtab)
1130 	    return ENOENT;
1131 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1132 	    symval->name = ef->ddbstrtab + es->st_name;
1133 	    symval->value = (caddr_t) ef->address + es->st_value;
1134 	    symval->size = es->st_size;
1135 	    return 0;
1136 	}
1137 	return ENOENT;
1138 }
1139 
1140 static int
1141 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1142 		       c_linker_sym_t* sym, long* diffp)
1143 {
1144 	elf_file_t ef = (elf_file_t) lf;
1145 	u_long off = (uintptr_t) (void *) value;
1146 	u_long diff = off;
1147 	u_long st_value;
1148 	const Elf_Sym* es;
1149 	const Elf_Sym* best = 0;
1150 	int i;
1151 
1152 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1153 		if (es->st_name == 0)
1154 			continue;
1155 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1156 		if (off >= st_value) {
1157 			if (off - st_value < diff) {
1158 				diff = off - st_value;
1159 				best = es;
1160 				if (diff == 0)
1161 					break;
1162 			} else if (off - st_value == diff) {
1163 				best = es;
1164 			}
1165 		}
1166 	}
1167 	if (best == 0)
1168 		*diffp = off;
1169 	else
1170 		*diffp = diff;
1171 	*sym = (c_linker_sym_t) best;
1172 
1173 	return 0;
1174 }
1175 
1176 /*
1177  * Look up a linker set on an ELF system.
1178  */
1179 static int
1180 link_elf_lookup_set(linker_file_t lf, const char *name,
1181 		    void ***startp, void ***stopp, int *countp)
1182 {
1183 	c_linker_sym_t sym;
1184 	linker_symval_t symval;
1185 	char *setsym;
1186 	void **start, **stop;
1187 	int len, error = 0, count;
1188 
1189 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1190 	setsym = malloc(len, M_LINKER, M_WAITOK);
1191 	if (setsym == NULL)
1192 		return ENOMEM;
1193 
1194 	/* get address of first entry */
1195 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1196 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1197 	if (error)
1198 		goto out;
1199 	link_elf_symbol_values(lf, sym, &symval);
1200 	if (symval.value == 0) {
1201 		error = ESRCH;
1202 		goto out;
1203 	}
1204 	start = (void **)symval.value;
1205 
1206 	/* get address of last entry */
1207 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1208 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1209 	if (error)
1210 		goto out;
1211 	link_elf_symbol_values(lf, sym, &symval);
1212 	if (symval.value == 0) {
1213 		error = ESRCH;
1214 		goto out;
1215 	}
1216 	stop = (void **)symval.value;
1217 
1218 	/* and the number of entries */
1219 	count = stop - start;
1220 
1221 	/* and copy out */
1222 	if (startp)
1223 		*startp = start;
1224 	if (stopp)
1225 		*stopp = stop;
1226 	if (countp)
1227 		*countp = count;
1228 
1229 out:
1230 	free(setsym, M_LINKER);
1231 	return error;
1232 }
1233 
1234 static int
1235 link_elf_each_function_name(linker_file_t file,
1236   int (*callback)(const char *, void *), void *opaque) {
1237     elf_file_t ef = (elf_file_t)file;
1238     const Elf_Sym* symp;
1239     int i, error;
1240 
1241     /* Exhaustive search */
1242     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1243 	if (symp->st_value != 0 &&
1244 	    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1245 		error = callback(ef->ddbstrtab + symp->st_name, opaque);
1246 		if (error)
1247 		    return (error);
1248 	}
1249     }
1250     return (0);
1251 }
1252 
1253 static int
1254 link_elf_each_function_nameval(linker_file_t file,
1255     linker_function_nameval_callback_t callback, void *opaque)
1256 {
1257 	linker_symval_t symval;
1258 	elf_file_t ef = (elf_file_t)file;
1259 	const Elf_Sym* symp;
1260 	int i, error;
1261 
1262 	/* Exhaustive search */
1263 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1264 		if (symp->st_value != 0 &&
1265 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1266 			error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1267 			if (error)
1268 				return (error);
1269 			error = callback(file, i, &symval, opaque);
1270 			if (error)
1271 				return (error);
1272 		}
1273 	}
1274 	return (0);
1275 }
1276 
1277 #ifdef __ia64__
1278 /*
1279  * Each KLD has its own GP. The GP value for each load module is given by
1280  * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1281  * don't have direct access to the ELF file structure. The link_elf_get_gp()
1282  * function returns the GP given a pointer to a generic linker file struct.
1283  */
1284 Elf_Addr
1285 link_elf_get_gp(linker_file_t lf)
1286 {
1287 	elf_file_t ef = (elf_file_t)lf;
1288 	return (Elf_Addr)ef->got;
1289 }
1290 #endif
1291 
1292 const Elf_Sym *
1293 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1294 {
1295 	elf_file_t ef = (elf_file_t)lf;
1296 
1297 	if (symidx >= ef->nchains)
1298 		return (NULL);
1299 	return (ef->symtab + symidx);
1300 }
1301 
1302 const char *
1303 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1304 {
1305 	elf_file_t ef = (elf_file_t)lf;
1306 	const Elf_Sym *sym;
1307 
1308 	if (symidx >= ef->nchains)
1309 		return (NULL);
1310 	sym = ef->symtab + symidx;
1311 	return (ef->strtab + sym->st_name);
1312 }
1313 
1314 /*
1315  * Symbol lookup function that can be used when the symbol index is known (ie
1316  * in relocations). It uses the symbol index instead of doing a fully fledged
1317  * hash table based lookup when such is valid. For example for local symbols.
1318  * This is not only more efficient, it's also more correct. It's not always
1319  * the case that the symbol can be found through the hash table.
1320  */
1321 static Elf_Addr
1322 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1323 {
1324 	elf_file_t ef = (elf_file_t)lf;
1325 	const Elf_Sym *sym;
1326 	const char *symbol;
1327 
1328 	/* Don't even try to lookup the symbol if the index is bogus. */
1329 	if (symidx >= ef->nchains)
1330 		return (0);
1331 
1332 	sym = ef->symtab + symidx;
1333 
1334 	/*
1335 	 * Don't do a full lookup when the symbol is local. It may even
1336 	 * fail because it may not be found through the hash table.
1337 	 */
1338 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1339 		/* Force lookup failure when we have an insanity. */
1340 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1341 			return (0);
1342 		return ((Elf_Addr)ef->address + sym->st_value);
1343 	}
1344 
1345 	/*
1346 	 * XXX we can avoid doing a hash table based lookup for global
1347 	 * symbols as well. This however is not always valid, so we'll
1348 	 * just do it the hard way for now. Performance tweaks can
1349 	 * always be added.
1350 	 */
1351 
1352 	symbol = ef->strtab + sym->st_name;
1353 
1354 	/* Force a lookup failure if the symbol name is bogus. */
1355 	if (*symbol == 0)
1356 		return (0);
1357 
1358 	return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1359 }
1360 
1361 static void
1362 link_elf_reloc_local(linker_file_t lf)
1363 {
1364     const Elf_Rel *rellim;
1365     const Elf_Rel *rel;
1366     const Elf_Rela *relalim;
1367     const Elf_Rela *rela;
1368     elf_file_t ef = (elf_file_t)lf;
1369 
1370     /* Perform relocations without addend if there are any: */
1371     if ((rel = ef->rel) != NULL) {
1372 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1373 	while (rel < rellim) {
1374 	    elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1375 			    elf_lookup);
1376 	    rel++;
1377 	}
1378     }
1379 
1380     /* Perform relocations with addend if there are any: */
1381     if ((rela = ef->rela) != NULL) {
1382 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1383 	while (rela < relalim) {
1384 	    elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1385 			    elf_lookup);
1386 	    rela++;
1387 	}
1388     }
1389 }
1390