xref: /freebsd/sys/kern/link_elf.c (revision 908e960ea6343acd9515d89d5d5696f9d8bf090c)
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 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #ifdef GPROF
36 #include <sys/gmon.h>
37 #endif
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/mount.h>
43 #include <sys/proc.h>
44 #include <sys/namei.h>
45 #include <sys/fcntl.h>
46 #include <sys/vnode.h>
47 #include <sys/linker.h>
48 
49 #include <machine/elf.h>
50 
51 #include <security/mac/mac_framework.h>
52 
53 #include <vm/vm.h>
54 #include <vm/vm_param.h>
55 #ifdef SPARSE_MAPPING
56 #include <vm/vm_object.h>
57 #include <vm/vm_kern.h>
58 #include <vm/vm_extern.h>
59 #endif
60 #include <vm/pmap.h>
61 #include <vm/vm_map.h>
62 
63 #include <sys/link_elf.h>
64 
65 #ifdef DDB_CTF
66 #include <net/zlib.h>
67 #endif
68 
69 #include "linker_if.h"
70 
71 #define MAXSEGS 4
72 
73 typedef struct elf_file {
74     struct linker_file	lf;		/* Common fields */
75     int			preloaded;	/* Was file pre-loaded */
76     caddr_t		address;	/* Relocation address */
77 #ifdef SPARSE_MAPPING
78     vm_object_t		object;		/* VM object to hold file pages */
79 #endif
80     Elf_Dyn*		dynamic;	/* Symbol table etc. */
81     Elf_Hashelt		nbuckets;	/* DT_HASH info */
82     Elf_Hashelt		nchains;
83     const Elf_Hashelt*	buckets;
84     const Elf_Hashelt*	chains;
85     caddr_t		hash;
86     caddr_t		strtab;		/* DT_STRTAB */
87     int			strsz;		/* DT_STRSZ */
88     const Elf_Sym*	symtab;		/* DT_SYMTAB */
89     Elf_Addr*		got;		/* DT_PLTGOT */
90     const Elf_Rel*	pltrel;		/* DT_JMPREL */
91     int			pltrelsize;	/* DT_PLTRELSZ */
92     const Elf_Rela*	pltrela;	/* DT_JMPREL */
93     int			pltrelasize;	/* DT_PLTRELSZ */
94     const Elf_Rel*	rel;		/* DT_REL */
95     int			relsize;	/* DT_RELSZ */
96     const Elf_Rela*	rela;		/* DT_RELA */
97     int			relasize;	/* DT_RELASZ */
98     caddr_t		modptr;
99     const Elf_Sym*	ddbsymtab;	/* The symbol table we are using */
100     long		ddbsymcnt;	/* Number of symbols */
101     caddr_t		ddbstrtab;	/* String table */
102     long		ddbstrcnt;	/* number of bytes in string table */
103     caddr_t		symbase;	/* malloc'ed symbold base */
104     caddr_t		strbase;	/* malloc'ed string base */
105     caddr_t		ctftab;		/* CTF table */
106     long		ctfcnt;		/* number of bytes in CTF table */
107     caddr_t		ctfoff;		/* CTF offset table */
108     caddr_t		typoff;		/* Type offset table */
109     long		typlen;		/* Number of type entries. */
110 #ifdef GDB
111     struct link_map	gdb;		/* hooks for gdb */
112 #endif
113 } *elf_file_t;
114 
115 #include <kern/kern_ctf.c>
116 
117 static int	link_elf_link_common_finish(linker_file_t);
118 static int	link_elf_link_preload(linker_class_t cls,
119 				      const char*, linker_file_t*);
120 static int	link_elf_link_preload_finish(linker_file_t);
121 static int	link_elf_load_file(linker_class_t, const char*, linker_file_t*);
122 static int	link_elf_lookup_symbol(linker_file_t, const char*,
123 				       c_linker_sym_t*);
124 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
125 static int	link_elf_search_symbol(linker_file_t, caddr_t value,
126 				       c_linker_sym_t* sym, long* diffp);
127 
128 static void	link_elf_unload_file(linker_file_t);
129 static void	link_elf_unload_preload(linker_file_t);
130 static int	link_elf_lookup_set(linker_file_t, const char *,
131 				    void ***, void ***, int *);
132 static int	link_elf_each_function_name(linker_file_t,
133 				int (*)(const char *, void *),
134 				void *);
135 static int	link_elf_each_function_nameval(linker_file_t,
136 				linker_function_nameval_callback_t,
137 				void *);
138 static void	link_elf_reloc_local(linker_file_t);
139 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
140 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
141 static Elf_Addr	elf_lookup(linker_file_t lf, Elf_Size symidx, int deps);
142 
143 static kobj_method_t link_elf_methods[] = {
144     KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
145     KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
146     KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
147     KOBJMETHOD(linker_unload,		link_elf_unload_file),
148     KOBJMETHOD(linker_load_file,	link_elf_load_file),
149     KOBJMETHOD(linker_link_preload,	link_elf_link_preload),
150     KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
151     KOBJMETHOD(linker_lookup_set,	link_elf_lookup_set),
152     KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
153     KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
154     KOBJMETHOD(linker_ctf_get,          link_elf_ctf_get),
155     KOBJMETHOD(linker_symtab_get, 	link_elf_symtab_get),
156     KOBJMETHOD(linker_strtab_get, 	link_elf_strtab_get),
157     { 0, 0 }
158 };
159 
160 static struct linker_class link_elf_class = {
161 #if ELF_TARG_CLASS == ELFCLASS32
162     "elf32",
163 #else
164     "elf64",
165 #endif
166     link_elf_methods, sizeof(struct elf_file)
167 };
168 
169 static int		parse_dynamic(elf_file_t ef);
170 static int		relocate_file(elf_file_t ef);
171 static int		link_elf_preload_parse_symbols(elf_file_t ef);
172 
173 #ifdef GDB
174 static void		r_debug_state(struct r_debug *dummy_one,
175 				      struct link_map *dummy_two);
176 
177 /*
178  * A list of loaded modules for GDB to use for loading symbols.
179  */
180 struct r_debug r_debug;
181 
182 #define GDB_STATE(s)	r_debug.r_state = s; r_debug_state(NULL, NULL);
183 
184 /*
185  * Function for the debugger to set a breakpoint on to gain control.
186  */
187 static void
188 r_debug_state(struct r_debug *dummy_one __unused,
189 	      struct link_map *dummy_two __unused)
190 {
191 }
192 
193 static void
194 link_elf_add_gdb(struct link_map *l)
195 {
196     struct link_map *prev;
197 
198     l->l_next = NULL;
199 
200     if (r_debug.r_map == NULL) {
201 	/* Add first. */
202 	l->l_prev = NULL;
203 	r_debug.r_map = l;
204     } else {
205 	/* Append to list. */
206 	for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
207 	    ;
208 	l->l_prev = prev;
209 	prev->l_next = l;
210     }
211 }
212 
213 static void
214 link_elf_delete_gdb(struct link_map *l)
215 {
216     if (l->l_prev == NULL) {
217 	/* Remove first. */
218 	if ((r_debug.r_map = l->l_next) != NULL)
219 	    l->l_next->l_prev = NULL;
220     } else {
221 	/* Remove any but first. */
222 	if ((l->l_prev->l_next = l->l_next) != NULL)
223 	    l->l_next->l_prev = l->l_prev;
224     }
225 }
226 #endif /* GDB */
227 
228 #ifdef __ia64__
229 Elf_Addr link_elf_get_gp(linker_file_t);
230 #endif
231 
232 /*
233  * The kernel symbol table starts here.
234  */
235 extern struct _dynamic _DYNAMIC;
236 
237 static void
238 link_elf_error(const char *filename, const char *s)
239 {
240 	if (filename == NULL)
241 		printf("kldload: %s\n", s);
242 	else
243 		printf("kldload: %s: %s\n", filename, s);
244 }
245 
246 /*
247  * Actions performed after linking/loading both the preloaded kernel and any
248  * modules; whether preloaded or dynamicly loaded.
249  */
250 static int
251 link_elf_link_common_finish(linker_file_t lf)
252 {
253 #ifdef GDB
254     elf_file_t ef = (elf_file_t)lf;
255     char *newfilename;
256 #endif
257     int error;
258 
259     /* Notify MD code that a module is being loaded. */
260     error = elf_cpu_load_file(lf);
261     if (error)
262 	return (error);
263 
264 #ifdef GDB
265     GDB_STATE(RT_ADD);
266     ef->gdb.l_addr = lf->address;
267     newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
268     strcpy(newfilename, lf->filename);
269     ef->gdb.l_name = newfilename;
270     ef->gdb.l_ld = ef->dynamic;
271     link_elf_add_gdb(&ef->gdb);
272     GDB_STATE(RT_CONSISTENT);
273 #endif
274 
275     return (0);
276 }
277 
278 static void
279 link_elf_init(void* arg)
280 {
281     Elf_Dyn	*dp;
282     caddr_t	modptr, baseptr, sizeptr;
283     elf_file_t	ef;
284     char	*modname;
285 
286     linker_add_class(&link_elf_class);
287 
288     dp = (Elf_Dyn*) &_DYNAMIC;
289     modname = NULL;
290     modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
291     if (modptr == NULL)
292 	modptr = preload_search_by_type("elf kernel");
293     if (modptr)
294 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
295     if (modname == NULL)
296 	modname = "kernel";
297     linker_kernel_file = linker_make_file(modname, &link_elf_class);
298     if (linker_kernel_file == NULL)
299 	panic("link_elf_init: Can't create linker structures for kernel");
300 
301     ef = (elf_file_t) linker_kernel_file;
302     ef->preloaded = 1;
303     ef->address = 0;
304 #ifdef SPARSE_MAPPING
305     ef->object = 0;
306 #endif
307     ef->dynamic = dp;
308 
309     if (dp)
310 	parse_dynamic(ef);
311     linker_kernel_file->address = (caddr_t) KERNBASE;
312     linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
313 
314     if (modptr) {
315 	ef->modptr = modptr;
316 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
317 	if (baseptr)
318 	    linker_kernel_file->address = *(caddr_t *)baseptr;
319 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
320 	if (sizeptr)
321 	    linker_kernel_file->size = *(size_t *)sizeptr;
322     }
323     (void)link_elf_preload_parse_symbols(ef);
324 
325 #ifdef GDB
326     r_debug.r_map = NULL;
327     r_debug.r_brk = r_debug_state;
328     r_debug.r_state = RT_CONSISTENT;
329 #endif
330 
331     (void)link_elf_link_common_finish(linker_kernel_file);
332     linker_kernel_file->flags |= LINKER_FILE_LINKED;
333 }
334 
335 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
336 
337 static int
338 link_elf_preload_parse_symbols(elf_file_t ef)
339 {
340     caddr_t	pointer;
341     caddr_t	ssym, esym, base;
342     caddr_t	strtab;
343     int		strcnt;
344     Elf_Sym*	symtab;
345     int		symcnt;
346 
347     if (ef->modptr == NULL)
348 	return 0;
349     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
350     if (pointer == NULL)
351 	return 0;
352     ssym = *(caddr_t *)pointer;
353     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
354     if (pointer == NULL)
355 	return 0;
356     esym = *(caddr_t *)pointer;
357 
358     base = ssym;
359 
360     symcnt = *(long *)base;
361     base += sizeof(long);
362     symtab = (Elf_Sym *)base;
363     base += roundup(symcnt, sizeof(long));
364 
365     if (base > esym || base < ssym) {
366 	printf("Symbols are corrupt!\n");
367 	return EINVAL;
368     }
369 
370     strcnt = *(long *)base;
371     base += sizeof(long);
372     strtab = base;
373     base += roundup(strcnt, sizeof(long));
374 
375     if (base > esym || base < ssym) {
376 	printf("Symbols are corrupt!\n");
377 	return EINVAL;
378     }
379 
380     ef->ddbsymtab = symtab;
381     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
382     ef->ddbstrtab = strtab;
383     ef->ddbstrcnt = strcnt;
384 
385     return 0;
386 }
387 
388 static int
389 parse_dynamic(elf_file_t ef)
390 {
391     Elf_Dyn *dp;
392     int plttype = DT_REL;
393 
394     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
395 	switch (dp->d_tag) {
396 	case DT_HASH:
397 	{
398 	    /* From src/libexec/rtld-elf/rtld.c */
399 	    const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
400 		(ef->address + dp->d_un.d_ptr);
401 	    ef->nbuckets = hashtab[0];
402 	    ef->nchains = hashtab[1];
403 	    ef->buckets = hashtab + 2;
404 	    ef->chains = ef->buckets + ef->nbuckets;
405 	    break;
406 	}
407 	case DT_STRTAB:
408 	    ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
409 	    break;
410 	case DT_STRSZ:
411 	    ef->strsz = dp->d_un.d_val;
412 	    break;
413 	case DT_SYMTAB:
414 	    ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
415 	    break;
416 	case DT_SYMENT:
417 	    if (dp->d_un.d_val != sizeof(Elf_Sym))
418 		return ENOEXEC;
419 	    break;
420 	case DT_PLTGOT:
421 	    ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
422 	    break;
423 	case DT_REL:
424 	    ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
425 	    break;
426 	case DT_RELSZ:
427 	    ef->relsize = dp->d_un.d_val;
428 	    break;
429 	case DT_RELENT:
430 	    if (dp->d_un.d_val != sizeof(Elf_Rel))
431 		return ENOEXEC;
432 	    break;
433 	case DT_JMPREL:
434 	    ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
435 	    break;
436 	case DT_PLTRELSZ:
437 	    ef->pltrelsize = dp->d_un.d_val;
438 	    break;
439 	case DT_RELA:
440 	    ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
441 	    break;
442 	case DT_RELASZ:
443 	    ef->relasize = dp->d_un.d_val;
444 	    break;
445 	case DT_RELAENT:
446 	    if (dp->d_un.d_val != sizeof(Elf_Rela))
447 		return ENOEXEC;
448 	    break;
449 	case DT_PLTREL:
450 	    plttype = dp->d_un.d_val;
451 	    if (plttype != DT_REL && plttype != DT_RELA)
452 		return ENOEXEC;
453 	    break;
454 #ifdef GDB
455 	case DT_DEBUG:
456 	    dp->d_un.d_ptr = (Elf_Addr) &r_debug;
457 	    break;
458 #endif
459 	}
460     }
461 
462     if (plttype == DT_RELA) {
463 	ef->pltrela = (const Elf_Rela *) ef->pltrel;
464 	ef->pltrel = NULL;
465 	ef->pltrelasize = ef->pltrelsize;
466 	ef->pltrelsize = 0;
467     }
468 
469     ef->ddbsymtab = ef->symtab;
470     ef->ddbsymcnt = ef->nchains;
471     ef->ddbstrtab = ef->strtab;
472     ef->ddbstrcnt = ef->strsz;
473 
474     return 0;
475 }
476 
477 static int
478 link_elf_link_preload(linker_class_t cls,
479 		      const char* filename, linker_file_t *result)
480 {
481     caddr_t		modptr, baseptr, sizeptr, dynptr;
482     char		*type;
483     elf_file_t		ef;
484     linker_file_t	lf;
485     int			error;
486     vm_offset_t		dp;
487 
488     /* Look to see if we have the file preloaded */
489     modptr = preload_search_by_name(filename);
490     if (modptr == NULL)
491 	return ENOENT;
492 
493     type = (char *)preload_search_info(modptr, MODINFO_TYPE);
494     baseptr = preload_search_info(modptr, MODINFO_ADDR);
495     sizeptr = preload_search_info(modptr, MODINFO_SIZE);
496     dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
497     if (type == NULL ||
498 	(strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
499 	 strcmp(type, "elf module") != 0))
500 	return (EFTYPE);
501     if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
502 	return (EINVAL);
503 
504     lf = linker_make_file(filename, &link_elf_class);
505     if (lf == NULL) {
506 	return ENOMEM;
507     }
508 
509     ef = (elf_file_t) lf;
510     ef->preloaded = 1;
511     ef->modptr = modptr;
512     ef->address = *(caddr_t *)baseptr;
513 #ifdef SPARSE_MAPPING
514     ef->object = 0;
515 #endif
516     dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
517     ef->dynamic = (Elf_Dyn *)dp;
518     lf->address = ef->address;
519     lf->size = *(size_t *)sizeptr;
520 
521     error = parse_dynamic(ef);
522     if (error) {
523 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
524 	return error;
525     }
526     link_elf_reloc_local(lf);
527     *result = lf;
528     return (0);
529 }
530 
531 static int
532 link_elf_link_preload_finish(linker_file_t lf)
533 {
534     elf_file_t		ef;
535     int error;
536 
537     ef = (elf_file_t) lf;
538 #if 0	/* this will be more trouble than it's worth for now */
539     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
540 	if (dp->d_tag != DT_NEEDED)
541 	    continue;
542 	modname = ef->strtab + dp->d_un.d_val;
543 	error = linker_load_module(modname, lf);
544 	if (error)
545 	    goto out;
546     }
547 #endif
548     error = relocate_file(ef);
549     if (error)
550 	return error;
551     (void)link_elf_preload_parse_symbols(ef);
552 
553     return (link_elf_link_common_finish(lf));
554 }
555 
556 static int
557 link_elf_load_file(linker_class_t cls, const char* filename,
558 	linker_file_t* result)
559 {
560     struct nameidata nd;
561     struct thread* td = curthread;	/* XXX */
562     Elf_Ehdr *hdr;
563     caddr_t firstpage;
564     int nbytes, i;
565     Elf_Phdr *phdr;
566     Elf_Phdr *phlimit;
567     Elf_Phdr *segs[MAXSEGS];
568     int nsegs;
569     Elf_Phdr *phdyn;
570     Elf_Phdr *phphdr;
571     caddr_t mapbase;
572     size_t mapsize;
573     Elf_Off base_offset;
574     Elf_Addr base_vaddr;
575     Elf_Addr base_vlimit;
576     int error = 0;
577     int resid, flags;
578     elf_file_t ef;
579     linker_file_t lf;
580     Elf_Shdr *shdr;
581     int symtabindex;
582     int symstrindex;
583     int symcnt;
584     int strcnt;
585     int vfslocked;
586 
587     shdr = NULL;
588     lf = NULL;
589 
590     NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
591     flags = FREAD;
592     error = vn_open(&nd, &flags, 0, NULL);
593     if (error)
594 	return error;
595     vfslocked = NDHASGIANT(&nd);
596     NDFREE(&nd, NDF_ONLY_PNBUF);
597     if (nd.ni_vp->v_type != VREG) {
598 	error = ENOEXEC;
599 	firstpage = NULL;
600 	goto out;
601     }
602 #ifdef MAC
603     error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
604     if (error) {
605 	firstpage = NULL;
606 	goto out;
607     }
608 #endif
609 
610     /*
611      * Read the elf header from the file.
612      */
613     firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
614     if (firstpage == NULL) {
615 	error = ENOMEM;
616 	goto out;
617     }
618     hdr = (Elf_Ehdr *)firstpage;
619     error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
620 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
621 		    &resid, td);
622     nbytes = PAGE_SIZE - resid;
623     if (error)
624 	goto out;
625 
626     if (!IS_ELF(*hdr)) {
627 	error = ENOEXEC;
628 	goto out;
629     }
630 
631     if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
632       || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
633 	link_elf_error(filename, "Unsupported file layout");
634 	error = ENOEXEC;
635 	goto out;
636     }
637     if (hdr->e_ident[EI_VERSION] != EV_CURRENT
638       || hdr->e_version != EV_CURRENT) {
639 	link_elf_error(filename, "Unsupported file version");
640 	error = ENOEXEC;
641 	goto out;
642     }
643     if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
644 	error = ENOSYS;
645 	goto out;
646     }
647     if (hdr->e_machine != ELF_TARG_MACH) {
648 	link_elf_error(filename, "Unsupported machine");
649 	error = ENOEXEC;
650 	goto out;
651     }
652 
653     /*
654      * We rely on the program header being in the first page.  This is
655      * not strictly required by the ABI specification, but it seems to
656      * always true in practice.  And, it simplifies things considerably.
657      */
658     if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
659 	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
660 	  (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
661 	link_elf_error(filename, "Unreadable program headers");
662 
663     /*
664      * Scan the program header entries, and save key information.
665      *
666      * We rely on there being exactly two load segments, text and data,
667      * in that order.
668      */
669     phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
670     phlimit = phdr + hdr->e_phnum;
671     nsegs = 0;
672     phdyn = NULL;
673     phphdr = NULL;
674     while (phdr < phlimit) {
675 	switch (phdr->p_type) {
676 
677 	case PT_LOAD:
678 	    if (nsegs == MAXSEGS) {
679 		link_elf_error(filename, "Too many sections");
680 		error = ENOEXEC;
681 		goto out;
682 	    }
683 	    /*
684 	     * XXX: We just trust they come in right order ??
685 	     */
686 	    segs[nsegs] = phdr;
687 	    ++nsegs;
688 	    break;
689 
690 	case PT_PHDR:
691 	    phphdr = phdr;
692 	    break;
693 
694 	case PT_DYNAMIC:
695 	    phdyn = phdr;
696 	    break;
697 
698 	case PT_INTERP:
699 	    error = ENOSYS;
700 	    goto out;
701 	}
702 
703 	++phdr;
704     }
705     if (phdyn == NULL) {
706 	link_elf_error(filename, "Object is not dynamically-linked");
707 	error = ENOEXEC;
708 	goto out;
709     }
710     if (nsegs == 0) {
711 	link_elf_error(filename, "No sections");
712 	error = ENOEXEC;
713 	goto out;
714     }
715 
716     /*
717      * Allocate the entire address space of the object, to stake out our
718      * contiguous region, and to establish the base address for relocation.
719      */
720     base_offset = trunc_page(segs[0]->p_offset);
721     base_vaddr = trunc_page(segs[0]->p_vaddr);
722     base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
723 	segs[nsegs - 1]->p_memsz);
724     mapsize = base_vlimit - base_vaddr;
725 
726     lf = linker_make_file(filename, &link_elf_class);
727     if (!lf) {
728 	error = ENOMEM;
729 	goto out;
730     }
731 
732     ef = (elf_file_t) lf;
733 #ifdef SPARSE_MAPPING
734     ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
735     if (ef->object == NULL) {
736 	error = ENOMEM;
737 	goto out;
738     }
739     ef->address = (caddr_t) vm_map_min(kernel_map);
740     error = vm_map_find(kernel_map, ef->object, 0,
741 			(vm_offset_t *) &ef->address,
742 			mapsize, 1,
743 			VM_PROT_ALL, VM_PROT_ALL, 0);
744     if (error) {
745 	vm_object_deallocate(ef->object);
746 	ef->object = 0;
747 	goto out;
748     }
749 #else
750     ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
751     if (!ef->address) {
752 	error = ENOMEM;
753 	goto out;
754     }
755 #endif
756     mapbase = ef->address;
757 
758     /*
759      * Read the text and data sections and zero the bss.
760      */
761     for (i = 0; i < nsegs; i++) {
762 	caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
763 	error = vn_rdwr(UIO_READ, nd.ni_vp,
764 			segbase, segs[i]->p_filesz, segs[i]->p_offset,
765 			UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
766 			&resid, td);
767 	if (error) {
768 	    goto out;
769 	}
770 	bzero(segbase + segs[i]->p_filesz,
771 	      segs[i]->p_memsz - segs[i]->p_filesz);
772 
773 #ifdef SPARSE_MAPPING
774 	/*
775 	 * Wire down the pages
776 	 */
777 	error = vm_map_wire(kernel_map,
778 		    (vm_offset_t) segbase,
779 		    (vm_offset_t) segbase + segs[i]->p_memsz,
780 		    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
781 	if (error != KERN_SUCCESS) {
782 	    error = ENOMEM;
783 	    goto out;
784 	}
785 #endif
786     }
787 
788 #ifdef GPROF
789     /* Update profiling information with the new text segment. */
790     mtx_lock(&Giant);
791     kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
792 	segs[0]->p_memsz));
793     mtx_unlock(&Giant);
794 #endif
795 
796     ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
797 
798     lf->address = ef->address;
799     lf->size = mapsize;
800 
801     error = parse_dynamic(ef);
802     if (error)
803 	goto out;
804     link_elf_reloc_local(lf);
805 
806     VOP_UNLOCK(nd.ni_vp, 0);
807     error = linker_load_dependencies(lf);
808     vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
809     if (error)
810 	goto out;
811 #if 0	/* this will be more trouble than it's worth for now */
812     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
813 	if (dp->d_tag != DT_NEEDED)
814 	    continue;
815 	modname = ef->strtab + dp->d_un.d_val;
816 	error = linker_load_module(modname, lf);
817 	if (error)
818 	    goto out;
819     }
820 #endif
821     error = relocate_file(ef);
822     if (error)
823 	goto out;
824 
825     /* Try and load the symbol table if it's present.  (you can strip it!) */
826     nbytes = hdr->e_shnum * hdr->e_shentsize;
827     if (nbytes == 0 || hdr->e_shoff == 0)
828 	goto nosyms;
829     shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
830     if (shdr == NULL) {
831 	error = ENOMEM;
832 	goto out;
833     }
834     error = vn_rdwr(UIO_READ, nd.ni_vp,
835 		    (caddr_t)shdr, nbytes, hdr->e_shoff,
836 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
837 		    &resid, td);
838     if (error)
839 	goto out;
840     symtabindex = -1;
841     symstrindex = -1;
842     for (i = 0; i < hdr->e_shnum; i++) {
843 	if (shdr[i].sh_type == SHT_SYMTAB) {
844 	    symtabindex = i;
845 	    symstrindex = shdr[i].sh_link;
846 	}
847     }
848     if (symtabindex < 0 || symstrindex < 0)
849 	goto nosyms;
850 
851     symcnt = shdr[symtabindex].sh_size;
852     ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
853     strcnt = shdr[symstrindex].sh_size;
854     ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
855 
856     if (ef->symbase == NULL || ef->strbase == NULL) {
857 	error = ENOMEM;
858 	goto out;
859     }
860     error = vn_rdwr(UIO_READ, nd.ni_vp,
861 		    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
862 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
863 		    &resid, td);
864     if (error)
865 	goto out;
866     error = vn_rdwr(UIO_READ, nd.ni_vp,
867 		    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
868 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
869 		    &resid, td);
870     if (error)
871 	goto out;
872 
873     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
874     ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
875     ef->ddbstrcnt = strcnt;
876     ef->ddbstrtab = ef->strbase;
877 
878     error = link_elf_link_common_finish(lf);
879     if (error)
880 	goto out;
881 
882 nosyms:
883 
884     *result = lf;
885 
886 out:
887     if (error && lf)
888 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
889     if (shdr)
890 	free(shdr, M_LINKER);
891     if (firstpage)
892 	free(firstpage, M_LINKER);
893     VOP_UNLOCK(nd.ni_vp, 0);
894     vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
895     VFS_UNLOCK_GIANT(vfslocked);
896 
897     return error;
898 }
899 
900 static void
901 link_elf_unload_file(linker_file_t file)
902 {
903     elf_file_t ef = (elf_file_t) file;
904 
905 #ifdef GDB
906     if (ef->gdb.l_ld) {
907 	GDB_STATE(RT_DELETE);
908 	free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
909 	link_elf_delete_gdb(&ef->gdb);
910 	GDB_STATE(RT_CONSISTENT);
911     }
912 #endif
913 
914     /* Notify MD code that a module is being unloaded. */
915     elf_cpu_unload_file(file);
916 
917     if (ef->preloaded) {
918 	link_elf_unload_preload(file);
919 	return;
920     }
921 
922 #ifdef SPARSE_MAPPING
923     if (ef->object) {
924 	vm_map_remove(kernel_map, (vm_offset_t) ef->address,
925 		      (vm_offset_t) ef->address
926 		      + (ef->object->size << PAGE_SHIFT));
927     }
928 #else
929     if (ef->address)
930 	free(ef->address, M_LINKER);
931 #endif
932     if (ef->symbase)
933 	free(ef->symbase, M_LINKER);
934     if (ef->strbase)
935 	free(ef->strbase, M_LINKER);
936     if (ef->ctftab)
937 	free(ef->ctftab, M_LINKER);
938     if (ef->ctfoff)
939 	free(ef->ctfoff, M_LINKER);
940     if (ef->typoff)
941 	free(ef->typoff, M_LINKER);
942 }
943 
944 static void
945 link_elf_unload_preload(linker_file_t file)
946 {
947     if (file->filename)
948 	preload_delete_name(file->filename);
949 }
950 
951 static const char *
952 symbol_name(elf_file_t ef, Elf_Size r_info)
953 {
954     const Elf_Sym *ref;
955 
956     if (ELF_R_SYM(r_info)) {
957 	ref = ef->symtab + ELF_R_SYM(r_info);
958 	return ef->strtab + ref->st_name;
959     } else
960 	return NULL;
961 }
962 
963 static int
964 relocate_file(elf_file_t ef)
965 {
966     const Elf_Rel *rellim;
967     const Elf_Rel *rel;
968     const Elf_Rela *relalim;
969     const Elf_Rela *rela;
970     const char *symname;
971 
972     /* Perform relocations without addend if there are any: */
973     rel = ef->rel;
974     if (rel) {
975 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
976 	while (rel < rellim) {
977 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
978 			  elf_lookup)) {
979 		symname = symbol_name(ef, rel->r_info);
980 		printf("link_elf: symbol %s undefined\n", symname);
981 		return ENOENT;
982 	    }
983 	    rel++;
984 	}
985     }
986 
987     /* Perform relocations with addend if there are any: */
988     rela = ef->rela;
989     if (rela) {
990 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
991 	while (rela < relalim) {
992 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
993 			  elf_lookup)) {
994 		symname = symbol_name(ef, rela->r_info);
995 		printf("link_elf: symbol %s undefined\n", symname);
996 		return ENOENT;
997 	    }
998 	    rela++;
999 	}
1000     }
1001 
1002     /* Perform PLT relocations without addend if there are any: */
1003     rel = ef->pltrel;
1004     if (rel) {
1005 	rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
1006 	while (rel < rellim) {
1007 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1008 			  elf_lookup)) {
1009 		symname = symbol_name(ef, rel->r_info);
1010 		printf("link_elf: symbol %s undefined\n", symname);
1011 		return ENOENT;
1012 	    }
1013 	    rel++;
1014 	}
1015     }
1016 
1017     /* Perform relocations with addend if there are any: */
1018     rela = ef->pltrela;
1019     if (rela) {
1020 	relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
1021 	while (rela < relalim) {
1022 	    if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1023 			  elf_lookup)) {
1024 		symname = symbol_name(ef, rela->r_info);
1025 		printf("link_elf: symbol %s undefined\n", symname);
1026 		return ENOENT;
1027 	    }
1028 	    rela++;
1029 	}
1030     }
1031 
1032     return 0;
1033 }
1034 
1035 /*
1036  * Hash function for symbol table lookup.  Don't even think about changing
1037  * this.  It is specified by the System V ABI.
1038  */
1039 static unsigned long
1040 elf_hash(const char *name)
1041 {
1042     const unsigned char *p = (const unsigned char *) name;
1043     unsigned long h = 0;
1044     unsigned long g;
1045 
1046     while (*p != '\0') {
1047 	h = (h << 4) + *p++;
1048 	if ((g = h & 0xf0000000) != 0)
1049 	    h ^= g >> 24;
1050 	h &= ~g;
1051     }
1052     return h;
1053 }
1054 
1055 static int
1056 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1057 {
1058     elf_file_t ef = (elf_file_t) lf;
1059     unsigned long symnum;
1060     const Elf_Sym* symp;
1061     const char *strp;
1062     unsigned long hash;
1063     int i;
1064 
1065     /* If we don't have a hash, bail. */
1066     if (ef->buckets == NULL || ef->nbuckets == 0) {
1067 	printf("link_elf_lookup_symbol: missing symbol hash table\n");
1068 	return ENOENT;
1069     }
1070 
1071     /* First, search hashed global symbols */
1072     hash = elf_hash(name);
1073     symnum = ef->buckets[hash % ef->nbuckets];
1074 
1075     while (symnum != STN_UNDEF) {
1076 	if (symnum >= ef->nchains) {
1077 	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
1078 	    return ENOENT;
1079 	}
1080 
1081 	symp = ef->symtab + symnum;
1082 	if (symp->st_name == 0) {
1083 	    printf("link_elf_lookup_symbol: corrupt symbol table\n");
1084 	    return ENOENT;
1085 	}
1086 
1087 	strp = ef->strtab + symp->st_name;
1088 
1089 	if (strcmp(name, strp) == 0) {
1090 	    if (symp->st_shndx != SHN_UNDEF ||
1091 		(symp->st_value != 0 &&
1092 		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1093 		*sym = (c_linker_sym_t) symp;
1094 		return 0;
1095 	    } else
1096 		return ENOENT;
1097 	}
1098 
1099 	symnum = ef->chains[symnum];
1100     }
1101 
1102     /* If we have not found it, look at the full table (if loaded) */
1103     if (ef->symtab == ef->ddbsymtab)
1104 	return ENOENT;
1105 
1106     /* Exhaustive search */
1107     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1108 	strp = ef->ddbstrtab + symp->st_name;
1109 	if (strcmp(name, strp) == 0) {
1110 	    if (symp->st_shndx != SHN_UNDEF ||
1111 		(symp->st_value != 0 &&
1112 		 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1113 		*sym = (c_linker_sym_t) symp;
1114 		return 0;
1115 	    } else
1116 		return ENOENT;
1117 	}
1118     }
1119 
1120     return ENOENT;
1121 }
1122 
1123 static int
1124 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1125 {
1126 	elf_file_t ef = (elf_file_t) lf;
1127 	const Elf_Sym* es = (const Elf_Sym*) sym;
1128 
1129 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1130 	    symval->name = ef->strtab + es->st_name;
1131 	    symval->value = (caddr_t) ef->address + es->st_value;
1132 	    symval->size = es->st_size;
1133 	    return 0;
1134 	}
1135 	if (ef->symtab == ef->ddbsymtab)
1136 	    return ENOENT;
1137 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1138 	    symval->name = ef->ddbstrtab + es->st_name;
1139 	    symval->value = (caddr_t) ef->address + es->st_value;
1140 	    symval->size = es->st_size;
1141 	    return 0;
1142 	}
1143 	return ENOENT;
1144 }
1145 
1146 static int
1147 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1148 		       c_linker_sym_t* sym, long* diffp)
1149 {
1150 	elf_file_t ef = (elf_file_t) lf;
1151 	u_long off = (uintptr_t) (void *) value;
1152 	u_long diff = off;
1153 	u_long st_value;
1154 	const Elf_Sym* es;
1155 	const Elf_Sym* best = 0;
1156 	int i;
1157 
1158 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1159 		if (es->st_name == 0)
1160 			continue;
1161 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1162 		if (off >= st_value) {
1163 			if (off - st_value < diff) {
1164 				diff = off - st_value;
1165 				best = es;
1166 				if (diff == 0)
1167 					break;
1168 			} else if (off - st_value == diff) {
1169 				best = es;
1170 			}
1171 		}
1172 	}
1173 	if (best == 0)
1174 		*diffp = off;
1175 	else
1176 		*diffp = diff;
1177 	*sym = (c_linker_sym_t) best;
1178 
1179 	return 0;
1180 }
1181 
1182 /*
1183  * Look up a linker set on an ELF system.
1184  */
1185 static int
1186 link_elf_lookup_set(linker_file_t lf, const char *name,
1187 		    void ***startp, void ***stopp, int *countp)
1188 {
1189 	c_linker_sym_t sym;
1190 	linker_symval_t symval;
1191 	char *setsym;
1192 	void **start, **stop;
1193 	int len, error = 0, count;
1194 
1195 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1196 	setsym = malloc(len, M_LINKER, M_WAITOK);
1197 	if (setsym == NULL)
1198 		return ENOMEM;
1199 
1200 	/* get address of first entry */
1201 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1202 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1203 	if (error)
1204 		goto out;
1205 	link_elf_symbol_values(lf, sym, &symval);
1206 	if (symval.value == 0) {
1207 		error = ESRCH;
1208 		goto out;
1209 	}
1210 	start = (void **)symval.value;
1211 
1212 	/* get address of last entry */
1213 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1214 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1215 	if (error)
1216 		goto out;
1217 	link_elf_symbol_values(lf, sym, &symval);
1218 	if (symval.value == 0) {
1219 		error = ESRCH;
1220 		goto out;
1221 	}
1222 	stop = (void **)symval.value;
1223 
1224 	/* and the number of entries */
1225 	count = stop - start;
1226 
1227 	/* and copy out */
1228 	if (startp)
1229 		*startp = start;
1230 	if (stopp)
1231 		*stopp = stop;
1232 	if (countp)
1233 		*countp = count;
1234 
1235 out:
1236 	free(setsym, M_LINKER);
1237 	return error;
1238 }
1239 
1240 static int
1241 link_elf_each_function_name(linker_file_t file,
1242   int (*callback)(const char *, void *), void *opaque) {
1243     elf_file_t ef = (elf_file_t)file;
1244     const Elf_Sym* symp;
1245     int i, error;
1246 
1247     /* Exhaustive search */
1248     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1249 	if (symp->st_value != 0 &&
1250 	    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1251 		error = callback(ef->ddbstrtab + symp->st_name, opaque);
1252 		if (error)
1253 		    return (error);
1254 	}
1255     }
1256     return (0);
1257 }
1258 
1259 static int
1260 link_elf_each_function_nameval(linker_file_t file,
1261     linker_function_nameval_callback_t callback, void *opaque)
1262 {
1263 	linker_symval_t symval;
1264 	elf_file_t ef = (elf_file_t)file;
1265 	const Elf_Sym* symp;
1266 	int i, error;
1267 
1268 	/* Exhaustive search */
1269 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1270 		if (symp->st_value != 0 &&
1271 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1272 			error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1273 			if (error)
1274 				return (error);
1275 			error = callback(file, i, &symval, opaque);
1276 			if (error)
1277 				return (error);
1278 		}
1279 	}
1280 	return (0);
1281 }
1282 
1283 #ifdef __ia64__
1284 /*
1285  * Each KLD has its own GP. The GP value for each load module is given by
1286  * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1287  * don't have direct access to the ELF file structure. The link_elf_get_gp()
1288  * function returns the GP given a pointer to a generic linker file struct.
1289  */
1290 Elf_Addr
1291 link_elf_get_gp(linker_file_t lf)
1292 {
1293 	elf_file_t ef = (elf_file_t)lf;
1294 	return (Elf_Addr)ef->got;
1295 }
1296 #endif
1297 
1298 const Elf_Sym *
1299 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1300 {
1301 	elf_file_t ef = (elf_file_t)lf;
1302 
1303 	if (symidx >= ef->nchains)
1304 		return (NULL);
1305 	return (ef->symtab + symidx);
1306 }
1307 
1308 const char *
1309 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1310 {
1311 	elf_file_t ef = (elf_file_t)lf;
1312 	const Elf_Sym *sym;
1313 
1314 	if (symidx >= ef->nchains)
1315 		return (NULL);
1316 	sym = ef->symtab + symidx;
1317 	return (ef->strtab + sym->st_name);
1318 }
1319 
1320 /*
1321  * Symbol lookup function that can be used when the symbol index is known (ie
1322  * in relocations). It uses the symbol index instead of doing a fully fledged
1323  * hash table based lookup when such is valid. For example for local symbols.
1324  * This is not only more efficient, it's also more correct. It's not always
1325  * the case that the symbol can be found through the hash table.
1326  */
1327 static Elf_Addr
1328 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1329 {
1330 	elf_file_t ef = (elf_file_t)lf;
1331 	const Elf_Sym *sym;
1332 	const char *symbol;
1333 
1334 	/* Don't even try to lookup the symbol if the index is bogus. */
1335 	if (symidx >= ef->nchains)
1336 		return (0);
1337 
1338 	sym = ef->symtab + symidx;
1339 
1340 	/*
1341 	 * Don't do a full lookup when the symbol is local. It may even
1342 	 * fail because it may not be found through the hash table.
1343 	 */
1344 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1345 		/* Force lookup failure when we have an insanity. */
1346 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1347 			return (0);
1348 		return ((Elf_Addr)ef->address + sym->st_value);
1349 	}
1350 
1351 	/*
1352 	 * XXX we can avoid doing a hash table based lookup for global
1353 	 * symbols as well. This however is not always valid, so we'll
1354 	 * just do it the hard way for now. Performance tweaks can
1355 	 * always be added.
1356 	 */
1357 
1358 	symbol = ef->strtab + sym->st_name;
1359 
1360 	/* Force a lookup failure if the symbol name is bogus. */
1361 	if (*symbol == 0)
1362 		return (0);
1363 
1364 	return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1365 }
1366 
1367 static void
1368 link_elf_reloc_local(linker_file_t lf)
1369 {
1370     const Elf_Rel *rellim;
1371     const Elf_Rel *rel;
1372     const Elf_Rela *relalim;
1373     const Elf_Rela *rela;
1374     elf_file_t ef = (elf_file_t)lf;
1375 
1376     /* Perform relocations without addend if there are any: */
1377     if ((rel = ef->rel) != NULL) {
1378 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1379 	while (rel < rellim) {
1380 	    elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1381 			    elf_lookup);
1382 	    rel++;
1383 	}
1384     }
1385 
1386     /* Perform relocations with addend if there are any: */
1387     if ((rela = ef->rela) != NULL) {
1388 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1389 	while (rela < relalim) {
1390 	    elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1391 			    elf_lookup);
1392 	    rela++;
1393 	}
1394     }
1395 }
1396 
1397 static long
1398 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1399 {
1400     elf_file_t ef = (elf_file_t)lf;
1401 
1402     *symtab = ef->ddbsymtab;
1403 
1404     if (*symtab == NULL)
1405         return (0);
1406 
1407     return (ef->ddbsymcnt);
1408 }
1409 
1410 static long
1411 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1412 {
1413     elf_file_t ef = (elf_file_t)lf;
1414 
1415     *strtab = ef->ddbstrtab;
1416 
1417     if (*strtab == NULL)
1418         return (0);
1419 
1420     return (ef->ddbstrcnt);
1421 }
1422