xref: /freebsd/sys/kern/link_elf.c (revision 13014ca04aad1931d41958b56f71a2c65b9a7a2c)
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 *filename, const char *s)
236 {
237 	if (filename == NULL)
238 		printf("kldload: %s\n", s);
239 	else
240 		printf("kldload: %s: %s\n", filename, s);
241 }
242 
243 /*
244  * Actions performed after linking/loading both the preloaded kernel and any
245  * modules; whether preloaded or dynamicly loaded.
246  */
247 static int
248 link_elf_link_common_finish(linker_file_t lf)
249 {
250 #ifdef GDB
251     elf_file_t ef = (elf_file_t)lf;
252     char *newfilename;
253 #endif
254     int error;
255 
256     /* Notify MD code that a module is being loaded. */
257     error = elf_cpu_load_file(lf);
258     if (error)
259 	return (error);
260 
261 #ifdef GDB
262     GDB_STATE(RT_ADD);
263     ef->gdb.l_addr = lf->address;
264     newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
265     strcpy(newfilename, lf->filename);
266     ef->gdb.l_name = newfilename;
267     ef->gdb.l_ld = ef->dynamic;
268     link_elf_add_gdb(&ef->gdb);
269     GDB_STATE(RT_CONSISTENT);
270 #endif
271 
272     return (0);
273 }
274 
275 static void
276 link_elf_init(void* arg)
277 {
278     Elf_Dyn	*dp;
279     caddr_t	modptr, baseptr, sizeptr;
280     elf_file_t	ef;
281     char	*modname;
282 
283     linker_add_class(&link_elf_class);
284 
285     dp = (Elf_Dyn*) &_DYNAMIC;
286     modname = NULL;
287     modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
288     if (modptr == NULL)
289 	modptr = preload_search_by_type("elf kernel");
290     if (modptr)
291 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
292     if (modname == NULL)
293 	modname = "kernel";
294     linker_kernel_file = linker_make_file(modname, &link_elf_class);
295     if (linker_kernel_file == NULL)
296 	panic("link_elf_init: Can't create linker structures for kernel");
297 
298     ef = (elf_file_t) linker_kernel_file;
299     ef->preloaded = 1;
300     ef->address = 0;
301 #ifdef SPARSE_MAPPING
302     ef->object = 0;
303 #endif
304     ef->dynamic = dp;
305 
306     if (dp)
307 	parse_dynamic(ef);
308     linker_kernel_file->address = (caddr_t) KERNBASE;
309     linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
310 
311     if (modptr) {
312 	ef->modptr = modptr;
313 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
314 	if (baseptr)
315 	    linker_kernel_file->address = *(caddr_t *)baseptr;
316 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
317 	if (sizeptr)
318 	    linker_kernel_file->size = *(size_t *)sizeptr;
319     }
320     (void)link_elf_preload_parse_symbols(ef);
321 
322 #ifdef GDB
323     r_debug.r_map = NULL;
324     r_debug.r_brk = r_debug_state;
325     r_debug.r_state = RT_CONSISTENT;
326 #endif
327 
328     (void)link_elf_link_common_finish(linker_kernel_file);
329     linker_kernel_file->flags |= LINKER_FILE_LINKED;
330 }
331 
332 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
333 
334 static int
335 link_elf_preload_parse_symbols(elf_file_t ef)
336 {
337     caddr_t	pointer;
338     caddr_t	ssym, esym, base;
339     caddr_t	strtab;
340     int		strcnt;
341     Elf_Sym*	symtab;
342     int		symcnt;
343 
344     if (ef->modptr == NULL)
345 	return 0;
346     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
347     if (pointer == NULL)
348 	return 0;
349     ssym = *(caddr_t *)pointer;
350     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
351     if (pointer == NULL)
352 	return 0;
353     esym = *(caddr_t *)pointer;
354 
355     base = ssym;
356 
357     symcnt = *(long *)base;
358     base += sizeof(long);
359     symtab = (Elf_Sym *)base;
360     base += roundup(symcnt, sizeof(long));
361 
362     if (base > esym || base < ssym) {
363 	printf("Symbols are corrupt!\n");
364 	return EINVAL;
365     }
366 
367     strcnt = *(long *)base;
368     base += sizeof(long);
369     strtab = base;
370     base += roundup(strcnt, sizeof(long));
371 
372     if (base > esym || base < ssym) {
373 	printf("Symbols are corrupt!\n");
374 	return EINVAL;
375     }
376 
377     ef->ddbsymtab = symtab;
378     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
379     ef->ddbstrtab = strtab;
380     ef->ddbstrcnt = strcnt;
381 
382     return 0;
383 }
384 
385 static int
386 parse_dynamic(elf_file_t ef)
387 {
388     Elf_Dyn *dp;
389     int plttype = DT_REL;
390 
391     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
392 	switch (dp->d_tag) {
393 	case DT_HASH:
394 	{
395 	    /* From src/libexec/rtld-elf/rtld.c */
396 	    const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
397 		(ef->address + dp->d_un.d_ptr);
398 	    ef->nbuckets = hashtab[0];
399 	    ef->nchains = hashtab[1];
400 	    ef->buckets = hashtab + 2;
401 	    ef->chains = ef->buckets + ef->nbuckets;
402 	    break;
403 	}
404 	case DT_STRTAB:
405 	    ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
406 	    break;
407 	case DT_STRSZ:
408 	    ef->strsz = dp->d_un.d_val;
409 	    break;
410 	case DT_SYMTAB:
411 	    ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
412 	    break;
413 	case DT_SYMENT:
414 	    if (dp->d_un.d_val != sizeof(Elf_Sym))
415 		return ENOEXEC;
416 	    break;
417 	case DT_PLTGOT:
418 	    ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
419 	    break;
420 	case DT_REL:
421 	    ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
422 	    break;
423 	case DT_RELSZ:
424 	    ef->relsize = dp->d_un.d_val;
425 	    break;
426 	case DT_RELENT:
427 	    if (dp->d_un.d_val != sizeof(Elf_Rel))
428 		return ENOEXEC;
429 	    break;
430 	case DT_JMPREL:
431 	    ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
432 	    break;
433 	case DT_PLTRELSZ:
434 	    ef->pltrelsize = dp->d_un.d_val;
435 	    break;
436 	case DT_RELA:
437 	    ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
438 	    break;
439 	case DT_RELASZ:
440 	    ef->relasize = dp->d_un.d_val;
441 	    break;
442 	case DT_RELAENT:
443 	    if (dp->d_un.d_val != sizeof(Elf_Rela))
444 		return ENOEXEC;
445 	    break;
446 	case DT_PLTREL:
447 	    plttype = dp->d_un.d_val;
448 	    if (plttype != DT_REL && plttype != DT_RELA)
449 		return ENOEXEC;
450 	    break;
451 #ifdef GDB
452 	case DT_DEBUG:
453 	    dp->d_un.d_ptr = (Elf_Addr) &r_debug;
454 	    break;
455 #endif
456 	}
457     }
458 
459     if (plttype == DT_RELA) {
460 	ef->pltrela = (const Elf_Rela *) ef->pltrel;
461 	ef->pltrel = NULL;
462 	ef->pltrelasize = ef->pltrelsize;
463 	ef->pltrelsize = 0;
464     }
465 
466     ef->ddbsymtab = ef->symtab;
467     ef->ddbsymcnt = ef->nchains;
468     ef->ddbstrtab = ef->strtab;
469     ef->ddbstrcnt = ef->strsz;
470 
471     return 0;
472 }
473 
474 static int
475 link_elf_link_preload(linker_class_t cls,
476 		      const char* filename, linker_file_t *result)
477 {
478     caddr_t		modptr, baseptr, sizeptr, dynptr;
479     char		*type;
480     elf_file_t		ef;
481     linker_file_t	lf;
482     int			error;
483     vm_offset_t		dp;
484 
485     /* Look to see if we have the file preloaded */
486     modptr = preload_search_by_name(filename);
487     if (modptr == NULL)
488 	return ENOENT;
489 
490     type = (char *)preload_search_info(modptr, MODINFO_TYPE);
491     baseptr = preload_search_info(modptr, MODINFO_ADDR);
492     sizeptr = preload_search_info(modptr, MODINFO_SIZE);
493     dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
494     if (type == NULL ||
495 	(strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
496 	 strcmp(type, "elf module") != 0))
497 	return (EFTYPE);
498     if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
499 	return (EINVAL);
500 
501     lf = linker_make_file(filename, &link_elf_class);
502     if (lf == NULL) {
503 	return ENOMEM;
504     }
505 
506     ef = (elf_file_t) lf;
507     ef->preloaded = 1;
508     ef->modptr = modptr;
509     ef->address = *(caddr_t *)baseptr;
510 #ifdef SPARSE_MAPPING
511     ef->object = 0;
512 #endif
513     dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
514     ef->dynamic = (Elf_Dyn *)dp;
515     lf->address = ef->address;
516     lf->size = *(size_t *)sizeptr;
517 
518     error = parse_dynamic(ef);
519     if (error) {
520 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
521 	return error;
522     }
523     link_elf_reloc_local(lf);
524     *result = lf;
525     return (0);
526 }
527 
528 static int
529 link_elf_link_preload_finish(linker_file_t lf)
530 {
531     elf_file_t		ef;
532     int error;
533 
534     ef = (elf_file_t) lf;
535 #if 0	/* this will be more trouble than it's worth for now */
536     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
537 	if (dp->d_tag != DT_NEEDED)
538 	    continue;
539 	modname = ef->strtab + dp->d_un.d_val;
540 	error = linker_load_module(modname, lf);
541 	if (error)
542 	    goto out;
543     }
544 #endif
545     error = relocate_file(ef);
546     if (error)
547 	return error;
548     (void)link_elf_preload_parse_symbols(ef);
549 
550     return (link_elf_link_common_finish(lf));
551 }
552 
553 static int
554 link_elf_load_file(linker_class_t cls, const char* filename,
555 	linker_file_t* result)
556 {
557     struct nameidata nd;
558     struct thread* td = curthread;	/* XXX */
559     Elf_Ehdr *hdr;
560     caddr_t firstpage;
561     int nbytes, i;
562     Elf_Phdr *phdr;
563     Elf_Phdr *phlimit;
564     Elf_Phdr *segs[MAXSEGS];
565     int nsegs;
566     Elf_Phdr *phdyn;
567     Elf_Phdr *phphdr;
568     caddr_t mapbase;
569     size_t mapsize;
570     Elf_Off base_offset;
571     Elf_Addr base_vaddr;
572     Elf_Addr base_vlimit;
573     int error = 0;
574     int resid, flags;
575     elf_file_t ef;
576     linker_file_t lf;
577     Elf_Shdr *shdr;
578     int symtabindex;
579     int symstrindex;
580     int symcnt;
581     int strcnt;
582     int vfslocked;
583 
584     shdr = NULL;
585     lf = NULL;
586 
587     NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
588     flags = FREAD;
589     error = vn_open(&nd, &flags, 0, NULL);
590     if (error)
591 	return error;
592     vfslocked = NDHASGIANT(&nd);
593     NDFREE(&nd, NDF_ONLY_PNBUF);
594     if (nd.ni_vp->v_type != VREG) {
595 	error = ENOEXEC;
596 	firstpage = NULL;
597 	goto out;
598     }
599 #ifdef MAC
600     error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
601     if (error) {
602 	firstpage = NULL;
603 	goto out;
604     }
605 #endif
606 
607     /*
608      * Read the elf header from the file.
609      */
610     firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
611     if (firstpage == NULL) {
612 	error = ENOMEM;
613 	goto out;
614     }
615     hdr = (Elf_Ehdr *)firstpage;
616     error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
617 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
618 		    &resid, td);
619     nbytes = PAGE_SIZE - resid;
620     if (error)
621 	goto out;
622 
623     if (!IS_ELF(*hdr)) {
624 	error = ENOEXEC;
625 	goto out;
626     }
627 
628     if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
629       || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
630 	link_elf_error(filename, "Unsupported file layout");
631 	error = ENOEXEC;
632 	goto out;
633     }
634     if (hdr->e_ident[EI_VERSION] != EV_CURRENT
635       || hdr->e_version != EV_CURRENT) {
636 	link_elf_error(filename, "Unsupported file version");
637 	error = ENOEXEC;
638 	goto out;
639     }
640     if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
641 	link_elf_error(filename, "Unsupported file type");
642 	error = ENOEXEC;
643 	goto out;
644     }
645     if (hdr->e_machine != ELF_TARG_MACH) {
646 	link_elf_error(filename, "Unsupported machine");
647 	error = ENOEXEC;
648 	goto out;
649     }
650 
651     /*
652      * We rely on the program header being in the first page.  This is
653      * not strictly required by the ABI specification, but it seems to
654      * always true in practice.  And, it simplifies things considerably.
655      */
656     if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
657 	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
658 	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
659 	link_elf_error(filename, "Unreadable program headers");
660 
661     /*
662      * Scan the program header entries, and save key information.
663      *
664      * We rely on there being exactly two load segments, text and data,
665      * in that order.
666      */
667     phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
668     phlimit = phdr + hdr->e_phnum;
669     nsegs = 0;
670     phdyn = NULL;
671     phphdr = NULL;
672     while (phdr < phlimit) {
673 	switch (phdr->p_type) {
674 
675 	case PT_LOAD:
676 	    if (nsegs == MAXSEGS) {
677 		link_elf_error(filename, "Too many sections");
678 		error = ENOEXEC;
679 		goto out;
680 	    }
681 	    /*
682 	     * XXX: We just trust they come in right order ??
683 	     */
684 	    segs[nsegs] = phdr;
685 	    ++nsegs;
686 	    break;
687 
688 	case PT_PHDR:
689 	    phphdr = phdr;
690 	    break;
691 
692 	case PT_DYNAMIC:
693 	    phdyn = phdr;
694 	    break;
695 
696 	case PT_INTERP:
697 	    link_elf_error(filename, "Unsupported file type");
698 	    error = ENOEXEC;
699 	    goto out;
700 	}
701 
702 	++phdr;
703     }
704     if (phdyn == NULL) {
705 	link_elf_error(filename, "Object is not dynamically-linked");
706 	error = ENOEXEC;
707 	goto out;
708     }
709     if (nsegs == 0) {
710 	link_elf_error(filename, "No sections");
711 	error = ENOEXEC;
712 	goto out;
713     }
714 
715     /*
716      * Allocate the entire address space of the object, to stake out our
717      * contiguous region, and to establish the base address for relocation.
718      */
719     base_offset = trunc_page(segs[0]->p_offset);
720     base_vaddr = trunc_page(segs[0]->p_vaddr);
721     base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
722 	segs[nsegs - 1]->p_memsz);
723     mapsize = base_vlimit - base_vaddr;
724 
725     lf = linker_make_file(filename, &link_elf_class);
726     if (!lf) {
727 	error = ENOMEM;
728 	goto out;
729     }
730 
731     ef = (elf_file_t) lf;
732 #ifdef SPARSE_MAPPING
733     ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
734     if (ef->object == NULL) {
735 	error = ENOMEM;
736 	goto out;
737     }
738     ef->address = (caddr_t) vm_map_min(kernel_map);
739     error = vm_map_find(kernel_map, ef->object, 0,
740 			(vm_offset_t *) &ef->address,
741 			mapsize, 1,
742 			VM_PROT_ALL, VM_PROT_ALL, 0);
743     if (error) {
744 	vm_object_deallocate(ef->object);
745 	ef->object = 0;
746 	goto out;
747     }
748 #else
749     ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
750     if (!ef->address) {
751 	error = ENOMEM;
752 	goto out;
753     }
754 #endif
755     mapbase = ef->address;
756 
757     /*
758      * Read the text and data sections and zero the bss.
759      */
760     for (i = 0; i < nsegs; i++) {
761 	caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
762 	error = vn_rdwr(UIO_READ, nd.ni_vp,
763 			segbase, segs[i]->p_filesz, segs[i]->p_offset,
764 			UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
765 			&resid, td);
766 	if (error) {
767 	    goto out;
768 	}
769 	bzero(segbase + segs[i]->p_filesz,
770 	      segs[i]->p_memsz - segs[i]->p_filesz);
771 
772 #ifdef SPARSE_MAPPING
773 	/*
774 	 * Wire down the pages
775 	 */
776 	error = vm_map_wire(kernel_map,
777 		    (vm_offset_t) segbase,
778 		    (vm_offset_t) segbase + segs[i]->p_memsz,
779 		    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
780 	if (error != KERN_SUCCESS) {
781 	    error = ENOMEM;
782 	    goto out;
783 	}
784 #endif
785     }
786 
787 #ifdef GPROF
788     /* Update profiling information with the new text segment. */
789     mtx_lock(&Giant);
790     kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
791 	segs[0]->p_memsz));
792     mtx_unlock(&Giant);
793 #endif
794 
795     ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
796 
797     lf->address = ef->address;
798     lf->size = mapsize;
799 
800     error = parse_dynamic(ef);
801     if (error)
802 	goto out;
803     link_elf_reloc_local(lf);
804 
805     VOP_UNLOCK(nd.ni_vp, 0);
806     error = linker_load_dependencies(lf);
807     vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
808     if (error)
809 	goto out;
810 #if 0	/* this will be more trouble than it's worth for now */
811     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
812 	if (dp->d_tag != DT_NEEDED)
813 	    continue;
814 	modname = ef->strtab + dp->d_un.d_val;
815 	error = linker_load_module(modname, lf);
816 	if (error)
817 	    goto out;
818     }
819 #endif
820     error = relocate_file(ef);
821     if (error)
822 	goto out;
823 
824     /* Try and load the symbol table if it's present.  (you can strip it!) */
825     nbytes = hdr->e_shnum * hdr->e_shentsize;
826     if (nbytes == 0 || hdr->e_shoff == 0)
827 	goto nosyms;
828     shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
829     if (shdr == NULL) {
830 	error = ENOMEM;
831 	goto out;
832     }
833     error = vn_rdwr(UIO_READ, nd.ni_vp,
834 		    (caddr_t)shdr, nbytes, hdr->e_shoff,
835 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
836 		    &resid, td);
837     if (error)
838 	goto out;
839     symtabindex = -1;
840     symstrindex = -1;
841     for (i = 0; i < hdr->e_shnum; i++) {
842 	if (shdr[i].sh_type == SHT_SYMTAB) {
843 	    symtabindex = i;
844 	    symstrindex = shdr[i].sh_link;
845 	}
846     }
847     if (symtabindex < 0 || symstrindex < 0)
848 	goto nosyms;
849 
850     symcnt = shdr[symtabindex].sh_size;
851     ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
852     strcnt = shdr[symstrindex].sh_size;
853     ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
854 
855     if (ef->symbase == NULL || ef->strbase == NULL) {
856 	error = ENOMEM;
857 	goto out;
858     }
859     error = vn_rdwr(UIO_READ, nd.ni_vp,
860 		    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
861 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
862 		    &resid, td);
863     if (error)
864 	goto out;
865     error = vn_rdwr(UIO_READ, nd.ni_vp,
866 		    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
867 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
868 		    &resid, td);
869     if (error)
870 	goto out;
871 
872     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
873     ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
874     ef->ddbstrcnt = strcnt;
875     ef->ddbstrtab = ef->strbase;
876 
877     error = link_elf_link_common_finish(lf);
878     if (error)
879 	goto out;
880 
881 nosyms:
882 
883     *result = lf;
884 
885 out:
886     if (error && lf)
887 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
888     if (shdr)
889 	free(shdr, M_LINKER);
890     if (firstpage)
891 	free(firstpage, M_LINKER);
892     VOP_UNLOCK(nd.ni_vp, 0);
893     vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
894     VFS_UNLOCK_GIANT(vfslocked);
895 
896     return error;
897 }
898 
899 static void
900 link_elf_unload_file(linker_file_t file)
901 {
902     elf_file_t ef = (elf_file_t) file;
903 
904 #ifdef GDB
905     if (ef->gdb.l_ld) {
906 	GDB_STATE(RT_DELETE);
907 	free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
908 	link_elf_delete_gdb(&ef->gdb);
909 	GDB_STATE(RT_CONSISTENT);
910     }
911 #endif
912 
913     /* Notify MD code that a module is being unloaded. */
914     elf_cpu_unload_file(file);
915 
916     if (ef->preloaded) {
917 	link_elf_unload_preload(file);
918 	return;
919     }
920 
921 #ifdef SPARSE_MAPPING
922     if (ef->object) {
923 	vm_map_remove(kernel_map, (vm_offset_t) ef->address,
924 		      (vm_offset_t) ef->address
925 		      + (ef->object->size << PAGE_SHIFT));
926     }
927 #else
928     if (ef->address)
929 	free(ef->address, M_LINKER);
930 #endif
931     if (ef->symbase)
932 	free(ef->symbase, M_LINKER);
933     if (ef->strbase)
934 	free(ef->strbase, M_LINKER);
935     if (ef->ctftab)
936 	free(ef->ctftab, M_LINKER);
937     if (ef->ctfoff)
938 	free(ef->ctfoff, M_LINKER);
939     if (ef->typoff)
940 	free(ef->typoff, M_LINKER);
941 }
942 
943 static void
944 link_elf_unload_preload(linker_file_t file)
945 {
946     if (file->filename)
947 	preload_delete_name(file->filename);
948 }
949 
950 static const char *
951 symbol_name(elf_file_t ef, Elf_Size r_info)
952 {
953     const Elf_Sym *ref;
954 
955     if (ELF_R_SYM(r_info)) {
956 	ref = ef->symtab + ELF_R_SYM(r_info);
957 	return ef->strtab + ref->st_name;
958     } else
959 	return NULL;
960 }
961 
962 static int
963 relocate_file(elf_file_t ef)
964 {
965     const Elf_Rel *rellim;
966     const Elf_Rel *rel;
967     const Elf_Rela *relalim;
968     const Elf_Rela *rela;
969     const char *symname;
970 
971     /* Perform relocations without addend if there are any: */
972     rel = ef->rel;
973     if (rel) {
974 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
975 	while (rel < rellim) {
976 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
977 			  elf_lookup)) {
978 		symname = symbol_name(ef, rel->r_info);
979 		printf("link_elf: symbol %s undefined\n", symname);
980 		return ENOENT;
981 	    }
982 	    rel++;
983 	}
984     }
985 
986     /* Perform relocations with addend if there are any: */
987     rela = ef->rela;
988     if (rela) {
989 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
990 	while (rela < relalim) {
991 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
992 			  elf_lookup)) {
993 		symname = symbol_name(ef, rela->r_info);
994 		printf("link_elf: symbol %s undefined\n", symname);
995 		return ENOENT;
996 	    }
997 	    rela++;
998 	}
999     }
1000 
1001     /* Perform PLT relocations without addend if there are any: */
1002     rel = ef->pltrel;
1003     if (rel) {
1004 	rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
1005 	while (rel < rellim) {
1006 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1007 			  elf_lookup)) {
1008 		symname = symbol_name(ef, rel->r_info);
1009 		printf("link_elf: symbol %s undefined\n", symname);
1010 		return ENOENT;
1011 	    }
1012 	    rel++;
1013 	}
1014     }
1015 
1016     /* Perform relocations with addend if there are any: */
1017     rela = ef->pltrela;
1018     if (rela) {
1019 	relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
1020 	while (rela < relalim) {
1021 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1022 			  elf_lookup)) {
1023 		symname = symbol_name(ef, rela->r_info);
1024 		printf("link_elf: symbol %s undefined\n", symname);
1025 		return ENOENT;
1026 	    }
1027 	    rela++;
1028 	}
1029     }
1030 
1031     return 0;
1032 }
1033 
1034 /*
1035  * Hash function for symbol table lookup.  Don't even think about changing
1036  * this.  It is specified by the System V ABI.
1037  */
1038 static unsigned long
1039 elf_hash(const char *name)
1040 {
1041     const unsigned char *p = (const unsigned char *) name;
1042     unsigned long h = 0;
1043     unsigned long g;
1044 
1045     while (*p != '\0') {
1046 	h = (h << 4) + *p++;
1047 	if ((g = h & 0xf0000000) != 0)
1048 	    h ^= g >> 24;
1049 	h &= ~g;
1050     }
1051     return h;
1052 }
1053 
1054 static int
1055 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1056 {
1057     elf_file_t ef = (elf_file_t) lf;
1058     unsigned long symnum;
1059     const Elf_Sym* symp;
1060     const char *strp;
1061     unsigned long hash;
1062     int i;
1063 
1064     /* If we don't have a hash, bail. */
1065     if (ef->buckets == NULL || ef->nbuckets == 0) {
1066 	printf("link_elf_lookup_symbol: missing symbol hash table\n");
1067 	return ENOENT;
1068     }
1069 
1070     /* First, search hashed global symbols */
1071     hash = elf_hash(name);
1072     symnum = ef->buckets[hash % ef->nbuckets];
1073 
1074     while (symnum != STN_UNDEF) {
1075 	if (symnum >= ef->nchains) {
1076 	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
1077 	    return ENOENT;
1078 	}
1079 
1080 	symp = ef->symtab + symnum;
1081 	if (symp->st_name == 0) {
1082 	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
1083 	    return ENOENT;
1084 	}
1085 
1086 	strp = ef->strtab + symp->st_name;
1087 
1088 	if (strcmp(name, strp) == 0) {
1089 	    if (symp->st_shndx != SHN_UNDEF ||
1090 		(symp->st_value != 0 &&
1091 		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1092 		*sym = (c_linker_sym_t) symp;
1093 		return 0;
1094 	    } else
1095 		return ENOENT;
1096 	}
1097 
1098 	symnum = ef->chains[symnum];
1099     }
1100 
1101     /* If we have not found it, look at the full table (if loaded) */
1102     if (ef->symtab == ef->ddbsymtab)
1103 	return ENOENT;
1104 
1105     /* Exhaustive search */
1106     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1107 	strp = ef->ddbstrtab + symp->st_name;
1108 	if (strcmp(name, strp) == 0) {
1109 	    if (symp->st_shndx != SHN_UNDEF ||
1110 		(symp->st_value != 0 &&
1111 		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1112 		*sym = (c_linker_sym_t) symp;
1113 		return 0;
1114 	    } else
1115 		return ENOENT;
1116 	}
1117     }
1118 
1119     return ENOENT;
1120 }
1121 
1122 static int
1123 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1124 {
1125 	elf_file_t ef = (elf_file_t) lf;
1126 	const Elf_Sym* es = (const Elf_Sym*) sym;
1127 
1128 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1129 	    symval->name = ef->strtab + es->st_name;
1130 	    symval->value = (caddr_t) ef->address + es->st_value;
1131 	    symval->size = es->st_size;
1132 	    return 0;
1133 	}
1134 	if (ef->symtab == ef->ddbsymtab)
1135 	    return ENOENT;
1136 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1137 	    symval->name = ef->ddbstrtab + es->st_name;
1138 	    symval->value = (caddr_t) ef->address + es->st_value;
1139 	    symval->size = es->st_size;
1140 	    return 0;
1141 	}
1142 	return ENOENT;
1143 }
1144 
1145 static int
1146 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1147 		       c_linker_sym_t* sym, long* diffp)
1148 {
1149 	elf_file_t ef = (elf_file_t) lf;
1150 	u_long off = (uintptr_t) (void *) value;
1151 	u_long diff = off;
1152 	u_long st_value;
1153 	const Elf_Sym* es;
1154 	const Elf_Sym* best = 0;
1155 	int i;
1156 
1157 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1158 		if (es->st_name == 0)
1159 			continue;
1160 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1161 		if (off >= st_value) {
1162 			if (off - st_value < diff) {
1163 				diff = off - st_value;
1164 				best = es;
1165 				if (diff == 0)
1166 					break;
1167 			} else if (off - st_value == diff) {
1168 				best = es;
1169 			}
1170 		}
1171 	}
1172 	if (best == 0)
1173 		*diffp = off;
1174 	else
1175 		*diffp = diff;
1176 	*sym = (c_linker_sym_t) best;
1177 
1178 	return 0;
1179 }
1180 
1181 /*
1182  * Look up a linker set on an ELF system.
1183  */
1184 static int
1185 link_elf_lookup_set(linker_file_t lf, const char *name,
1186 		    void ***startp, void ***stopp, int *countp)
1187 {
1188 	c_linker_sym_t sym;
1189 	linker_symval_t symval;
1190 	char *setsym;
1191 	void **start, **stop;
1192 	int len, error = 0, count;
1193 
1194 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1195 	setsym = malloc(len, M_LINKER, M_WAITOK);
1196 	if (setsym == NULL)
1197 		return ENOMEM;
1198 
1199 	/* get address of first entry */
1200 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1201 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1202 	if (error)
1203 		goto out;
1204 	link_elf_symbol_values(lf, sym, &symval);
1205 	if (symval.value == 0) {
1206 		error = ESRCH;
1207 		goto out;
1208 	}
1209 	start = (void **)symval.value;
1210 
1211 	/* get address of last entry */
1212 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1213 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1214 	if (error)
1215 		goto out;
1216 	link_elf_symbol_values(lf, sym, &symval);
1217 	if (symval.value == 0) {
1218 		error = ESRCH;
1219 		goto out;
1220 	}
1221 	stop = (void **)symval.value;
1222 
1223 	/* and the number of entries */
1224 	count = stop - start;
1225 
1226 	/* and copy out */
1227 	if (startp)
1228 		*startp = start;
1229 	if (stopp)
1230 		*stopp = stop;
1231 	if (countp)
1232 		*countp = count;
1233 
1234 out:
1235 	free(setsym, M_LINKER);
1236 	return error;
1237 }
1238 
1239 static int
1240 link_elf_each_function_name(linker_file_t file,
1241   int (*callback)(const char *, void *), void *opaque) {
1242     elf_file_t ef = (elf_file_t)file;
1243     const Elf_Sym* symp;
1244     int i, error;
1245 
1246     /* Exhaustive search */
1247     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1248 	if (symp->st_value != 0 &&
1249 	    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1250 		error = callback(ef->ddbstrtab + symp->st_name, opaque);
1251 		if (error)
1252 		    return (error);
1253 	}
1254     }
1255     return (0);
1256 }
1257 
1258 static int
1259 link_elf_each_function_nameval(linker_file_t file,
1260     linker_function_nameval_callback_t callback, void *opaque)
1261 {
1262 	linker_symval_t symval;
1263 	elf_file_t ef = (elf_file_t)file;
1264 	const Elf_Sym* symp;
1265 	int i, error;
1266 
1267 	/* Exhaustive search */
1268 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1269 		if (symp->st_value != 0 &&
1270 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1271 			error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1272 			if (error)
1273 				return (error);
1274 			error = callback(file, i, &symval, opaque);
1275 			if (error)
1276 				return (error);
1277 		}
1278 	}
1279 	return (0);
1280 }
1281 
1282 #ifdef __ia64__
1283 /*
1284  * Each KLD has its own GP. The GP value for each load module is given by
1285  * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1286  * don't have direct access to the ELF file structure. The link_elf_get_gp()
1287  * function returns the GP given a pointer to a generic linker file struct.
1288  */
1289 Elf_Addr
1290 link_elf_get_gp(linker_file_t lf)
1291 {
1292 	elf_file_t ef = (elf_file_t)lf;
1293 	return (Elf_Addr)ef->got;
1294 }
1295 #endif
1296 
1297 const Elf_Sym *
1298 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1299 {
1300 	elf_file_t ef = (elf_file_t)lf;
1301 
1302 	if (symidx >= ef->nchains)
1303 		return (NULL);
1304 	return (ef->symtab + symidx);
1305 }
1306 
1307 const char *
1308 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1309 {
1310 	elf_file_t ef = (elf_file_t)lf;
1311 	const Elf_Sym *sym;
1312 
1313 	if (symidx >= ef->nchains)
1314 		return (NULL);
1315 	sym = ef->symtab + symidx;
1316 	return (ef->strtab + sym->st_name);
1317 }
1318 
1319 /*
1320  * Symbol lookup function that can be used when the symbol index is known (ie
1321  * in relocations). It uses the symbol index instead of doing a fully fledged
1322  * hash table based lookup when such is valid. For example for local symbols.
1323  * This is not only more efficient, it's also more correct. It's not always
1324  * the case that the symbol can be found through the hash table.
1325  */
1326 static Elf_Addr
1327 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1328 {
1329 	elf_file_t ef = (elf_file_t)lf;
1330 	const Elf_Sym *sym;
1331 	const char *symbol;
1332 
1333 	/* Don't even try to lookup the symbol if the index is bogus. */
1334 	if (symidx >= ef->nchains)
1335 		return (0);
1336 
1337 	sym = ef->symtab + symidx;
1338 
1339 	/*
1340 	 * Don't do a full lookup when the symbol is local. It may even
1341 	 * fail because it may not be found through the hash table.
1342 	 */
1343 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1344 		/* Force lookup failure when we have an insanity. */
1345 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1346 			return (0);
1347 		return ((Elf_Addr)ef->address + sym->st_value);
1348 	}
1349 
1350 	/*
1351 	 * XXX we can avoid doing a hash table based lookup for global
1352 	 * symbols as well. This however is not always valid, so we'll
1353 	 * just do it the hard way for now. Performance tweaks can
1354 	 * always be added.
1355 	 */
1356 
1357 	symbol = ef->strtab + sym->st_name;
1358 
1359 	/* Force a lookup failure if the symbol name is bogus. */
1360 	if (*symbol == 0)
1361 		return (0);
1362 
1363 	return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1364 }
1365 
1366 static void
1367 link_elf_reloc_local(linker_file_t lf)
1368 {
1369     const Elf_Rel *rellim;
1370     const Elf_Rel *rel;
1371     const Elf_Rela *relalim;
1372     const Elf_Rela *rela;
1373     elf_file_t ef = (elf_file_t)lf;
1374 
1375     /* Perform relocations without addend if there are any: */
1376     if ((rel = ef->rel) != NULL) {
1377 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1378 	while (rel < rellim) {
1379 	    elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1380 			    elf_lookup);
1381 	    rel++;
1382 	}
1383     }
1384 
1385     /* Perform relocations with addend if there are any: */
1386     if ((rela = ef->rela) != NULL) {
1387 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1388 	while (rela < relalim) {
1389 	    elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1390 			    elf_lookup);
1391 	    rela++;
1392 	}
1393     }
1394 }
1395