xref: /freebsd/sys/kern/link_elf.c (revision 3f05af05ace08ae28892ecfd28b000822a5d7ae0)
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/pcpu.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 <net/vnet.h>
53 
54 #include <security/mac/mac_framework.h>
55 
56 #include <vm/vm.h>
57 #include <vm/vm_param.h>
58 #ifdef SPARSE_MAPPING
59 #include <vm/vm_object.h>
60 #include <vm/vm_kern.h>
61 #include <vm/vm_extern.h>
62 #endif
63 #include <vm/pmap.h>
64 #include <vm/vm_map.h>
65 
66 #include <sys/link_elf.h>
67 
68 #ifdef DDB_CTF
69 #include <net/zlib.h>
70 #endif
71 
72 #include "linker_if.h"
73 
74 #define MAXSEGS 4
75 
76 typedef struct elf_file {
77 	struct linker_file lf;		/* Common fields */
78 	int		preloaded;	/* Was file pre-loaded */
79 	caddr_t		address;	/* Relocation address */
80 #ifdef SPARSE_MAPPING
81 	vm_object_t	object;		/* VM object to hold file pages */
82 #endif
83 	Elf_Dyn		*dynamic;	/* Symbol table etc. */
84 	Elf_Hashelt	nbuckets;	/* DT_HASH info */
85 	Elf_Hashelt	nchains;
86 	const Elf_Hashelt *buckets;
87 	const Elf_Hashelt *chains;
88 	caddr_t		hash;
89 	caddr_t		strtab;		/* DT_STRTAB */
90 	int		strsz;		/* DT_STRSZ */
91 	const Elf_Sym	*symtab;		/* DT_SYMTAB */
92 	Elf_Addr	*got;		/* DT_PLTGOT */
93 	const Elf_Rel	*pltrel;	/* DT_JMPREL */
94 	int		pltrelsize;	/* DT_PLTRELSZ */
95 	const Elf_Rela	*pltrela;	/* DT_JMPREL */
96 	int		pltrelasize;	/* DT_PLTRELSZ */
97 	const Elf_Rel	*rel;		/* DT_REL */
98 	int		relsize;	/* DT_RELSZ */
99 	const Elf_Rela	*rela;		/* DT_RELA */
100 	int		relasize;	/* DT_RELASZ */
101 	caddr_t		modptr;
102 	const Elf_Sym	*ddbsymtab;	/* The symbol table we are using */
103 	long		ddbsymcnt;	/* Number of symbols */
104 	caddr_t		ddbstrtab;	/* String table */
105 	long		ddbstrcnt;	/* number of bytes in string table */
106 	caddr_t		symbase;	/* malloc'ed symbold base */
107 	caddr_t		strbase;	/* malloc'ed string base */
108 	caddr_t		ctftab;		/* CTF table */
109 	long		ctfcnt;		/* number of bytes in CTF table */
110 	caddr_t		ctfoff;		/* CTF offset table */
111 	caddr_t		typoff;		/* Type offset table */
112 	long		typlen;		/* Number of type entries. */
113 	Elf_Addr	pcpu_start;	/* Pre-relocation pcpu set start. */
114 	Elf_Addr	pcpu_stop;	/* Pre-relocation pcpu set stop. */
115 	Elf_Addr	pcpu_base;	/* Relocated pcpu set address. */
116 #ifdef VIMAGE
117 	Elf_Addr	vnet_start;	/* Pre-relocation vnet set start. */
118 	Elf_Addr	vnet_stop;	/* Pre-relocation vnet set stop. */
119 	Elf_Addr	vnet_base;	/* Relocated vnet set address. */
120 #endif
121 #ifdef GDB
122 	struct link_map	gdb;		/* hooks for gdb */
123 #endif
124 } *elf_file_t;
125 
126 struct elf_set {
127 	Elf_Addr	es_start;
128 	Elf_Addr	es_stop;
129 	Elf_Addr	es_base;
130 	TAILQ_ENTRY(elf_set)	es_link;
131 };
132 
133 TAILQ_HEAD(elf_set_head, elf_set);
134 
135 #include <kern/kern_ctf.c>
136 
137 static int	link_elf_link_common_finish(linker_file_t);
138 static int	link_elf_link_preload(linker_class_t cls,
139 				      const char *, linker_file_t *);
140 static int	link_elf_link_preload_finish(linker_file_t);
141 static int	link_elf_load_file(linker_class_t, const char *,
142 		    linker_file_t *);
143 static int	link_elf_lookup_symbol(linker_file_t, const char *,
144 		    c_linker_sym_t *);
145 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
146 		    linker_symval_t *);
147 static int	link_elf_search_symbol(linker_file_t, caddr_t,
148 		    c_linker_sym_t *, long *);
149 
150 static void	link_elf_unload_file(linker_file_t);
151 static void	link_elf_unload_preload(linker_file_t);
152 static int	link_elf_lookup_set(linker_file_t, const char *,
153 		    void ***, void ***, int *);
154 static int	link_elf_each_function_name(linker_file_t,
155 		    int (*)(const char *, void *), void *);
156 static int	link_elf_each_function_nameval(linker_file_t,
157 		    linker_function_nameval_callback_t, void *);
158 static void	link_elf_reloc_local(linker_file_t);
159 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
160 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
161 static Elf_Addr	elf_lookup(linker_file_t, Elf_Size, int);
162 
163 static kobj_method_t link_elf_methods[] = {
164 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
165 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
166 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
167 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
168 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
169 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
170 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
171 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
172 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
173 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
174 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
175 	KOBJMETHOD(linker_symtab_get,		link_elf_symtab_get),
176 	KOBJMETHOD(linker_strtab_get,		link_elf_strtab_get),
177 	{ 0, 0 }
178 };
179 
180 static struct linker_class link_elf_class = {
181 #if ELF_TARG_CLASS == ELFCLASS32
182 	"elf32",
183 #else
184 	"elf64",
185 #endif
186 	link_elf_methods, sizeof(struct elf_file)
187 };
188 
189 static int	parse_dynamic(elf_file_t);
190 static int	relocate_file(elf_file_t);
191 static int	link_elf_preload_parse_symbols(elf_file_t);
192 
193 static struct elf_set_head set_pcpu_list;
194 #ifdef VIMAGE
195 static struct elf_set_head set_vnet_list;
196 #endif
197 
198 static void
199 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
200 {
201 	struct elf_set *set, *iter;
202 
203 	set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
204 	set->es_start = start;
205 	set->es_stop = stop;
206 	set->es_base = base;
207 
208 	TAILQ_FOREACH(iter, list, es_link) {
209 
210 		KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
211 		    (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
212 		    ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
213 		    (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
214 		    (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
215 
216 		if (iter->es_start > set->es_start) {
217 			TAILQ_INSERT_BEFORE(iter, set, es_link);
218 			break;
219 		}
220 	}
221 
222 	if (iter == NULL)
223 		TAILQ_INSERT_TAIL(list, set, es_link);
224 }
225 
226 static int
227 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
228 {
229 	struct elf_set *set;
230 
231 	TAILQ_FOREACH(set, list, es_link) {
232 		if (addr < set->es_start)
233 			return (0);
234 		if (addr < set->es_stop) {
235 			*start = set->es_start;
236 			*base = set->es_base;
237 			return (1);
238 		}
239 	}
240 
241 	return (0);
242 }
243 
244 static void
245 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
246 {
247 	struct elf_set *set;
248 
249 	TAILQ_FOREACH(set, list, es_link) {
250 		if (start < set->es_start)
251 			break;
252 		if (start == set->es_start) {
253 			TAILQ_REMOVE(list, set, es_link);
254 			free(set, M_LINKER);
255 			return;
256 		}
257 	}
258 	KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
259 	    (uintmax_t)start));
260 }
261 
262 #ifdef GDB
263 static void	r_debug_state(struct r_debug *, struct link_map *);
264 
265 /*
266  * A list of loaded modules for GDB to use for loading symbols.
267  */
268 struct r_debug r_debug;
269 
270 #define GDB_STATE(s) do {				\
271 	r_debug.r_state = s; r_debug_state(NULL, NULL);	\
272 } while (0)
273 
274 /*
275  * Function for the debugger to set a breakpoint on to gain control.
276  */
277 static void
278 r_debug_state(struct r_debug *dummy_one __unused,
279 	      struct link_map *dummy_two __unused)
280 {
281 }
282 
283 static void
284 link_elf_add_gdb(struct link_map *l)
285 {
286 	struct link_map *prev;
287 
288 	l->l_next = NULL;
289 
290 	if (r_debug.r_map == NULL) {
291 		/* Add first. */
292 		l->l_prev = NULL;
293 		r_debug.r_map = l;
294 	} else {
295 		/* Append to list. */
296 		for (prev = r_debug.r_map;
297 		    prev->l_next != NULL;
298 		    prev = prev->l_next)
299 			;
300 		l->l_prev = prev;
301 		prev->l_next = l;
302 	}
303 }
304 
305 static void
306 link_elf_delete_gdb(struct link_map *l)
307 {
308 	if (l->l_prev == NULL) {
309 		/* Remove first. */
310 		if ((r_debug.r_map = l->l_next) != NULL)
311 			l->l_next->l_prev = NULL;
312 	} else {
313 		/* Remove any but first. */
314 		if ((l->l_prev->l_next = l->l_next) != NULL)
315 			l->l_next->l_prev = l->l_prev;
316 	}
317 }
318 #endif /* GDB */
319 
320 /*
321  * The kernel symbol table starts here.
322  */
323 extern struct _dynamic _DYNAMIC;
324 
325 static void
326 link_elf_error(const char *filename, const char *s)
327 {
328 	if (filename == NULL)
329 		printf("kldload: %s\n", s);
330 	else
331 		printf("kldload: %s: %s\n", filename, s);
332 }
333 
334 static void
335 link_elf_invoke_ctors(caddr_t addr, size_t size)
336 {
337 	void (**ctor)(void);
338 	size_t i, cnt;
339 
340 	if (addr == NULL || size == 0)
341 		return;
342 	cnt = size / sizeof(*ctor);
343 	ctor = (void *)addr;
344 	for (i = 0; i < cnt; i++) {
345 		if (ctor[i] != NULL)
346 			(*ctor[i])();
347 	}
348 }
349 
350 /*
351  * Actions performed after linking/loading both the preloaded kernel and any
352  * modules; whether preloaded or dynamicly loaded.
353  */
354 static int
355 link_elf_link_common_finish(linker_file_t lf)
356 {
357 #ifdef GDB
358 	elf_file_t ef = (elf_file_t)lf;
359 	char *newfilename;
360 #endif
361 	int error;
362 
363 	/* Notify MD code that a module is being loaded. */
364 	error = elf_cpu_load_file(lf);
365 	if (error != 0)
366 		return (error);
367 
368 #ifdef GDB
369 	GDB_STATE(RT_ADD);
370 	ef->gdb.l_addr = lf->address;
371 	newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
372 	strcpy(newfilename, lf->filename);
373 	ef->gdb.l_name = newfilename;
374 	ef->gdb.l_ld = ef->dynamic;
375 	link_elf_add_gdb(&ef->gdb);
376 	GDB_STATE(RT_CONSISTENT);
377 #endif
378 
379 	/* Invoke .ctors */
380 	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
381 	return (0);
382 }
383 
384 extern vm_offset_t __startkernel;
385 
386 static void
387 link_elf_init(void* arg)
388 {
389 	Elf_Dyn *dp;
390 	Elf_Addr *ctors_addrp;
391 	Elf_Size *ctors_sizep;
392 	caddr_t modptr, baseptr, sizeptr;
393 	elf_file_t ef;
394 	char *modname;
395 
396 	linker_add_class(&link_elf_class);
397 
398 	dp = (Elf_Dyn *)&_DYNAMIC;
399 	modname = NULL;
400 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
401 	if (modptr == NULL)
402 		modptr = preload_search_by_type("elf kernel");
403 	if (modptr != NULL)
404 		modname = (char *)preload_search_info(modptr, MODINFO_NAME);
405 	if (modname == NULL)
406 		modname = "kernel";
407 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
408 	if (linker_kernel_file == NULL)
409 		panic("%s: Can't create linker structures for kernel",
410 		    __func__);
411 
412 	ef = (elf_file_t) linker_kernel_file;
413 	ef->preloaded = 1;
414 #ifdef __powerpc__
415 	ef->address = (caddr_t) (__startkernel - KERNBASE);
416 #else
417 	ef->address = 0;
418 #endif
419 #ifdef SPARSE_MAPPING
420 	ef->object = 0;
421 #endif
422 	ef->dynamic = dp;
423 
424 	if (dp != NULL)
425 		parse_dynamic(ef);
426 	linker_kernel_file->address += KERNBASE;
427 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
428 
429 	if (modptr != NULL) {
430 		ef->modptr = modptr;
431 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
432 		if (baseptr != NULL)
433 			linker_kernel_file->address = *(caddr_t *)baseptr;
434 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
435 		if (sizeptr != NULL)
436 			linker_kernel_file->size = *(size_t *)sizeptr;
437 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
438 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
439 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
440 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
441 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
442 			linker_kernel_file->ctors_addr = ef->address +
443 			    *ctors_addrp;
444 			linker_kernel_file->ctors_size = *ctors_sizep;
445 		}
446 	}
447 	(void)link_elf_preload_parse_symbols(ef);
448 
449 #ifdef GDB
450 	r_debug.r_map = NULL;
451 	r_debug.r_brk = r_debug_state;
452 	r_debug.r_state = RT_CONSISTENT;
453 #endif
454 
455 	(void)link_elf_link_common_finish(linker_kernel_file);
456 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
457 	TAILQ_INIT(&set_pcpu_list);
458 #ifdef VIMAGE
459 	TAILQ_INIT(&set_vnet_list);
460 #endif
461 }
462 
463 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
464 
465 static int
466 link_elf_preload_parse_symbols(elf_file_t ef)
467 {
468 	caddr_t pointer;
469 	caddr_t ssym, esym, base;
470 	caddr_t strtab;
471 	int strcnt;
472 	Elf_Sym *symtab;
473 	int symcnt;
474 
475 	if (ef->modptr == NULL)
476 		return (0);
477 	pointer = preload_search_info(ef->modptr,
478 	    MODINFO_METADATA | MODINFOMD_SSYM);
479 	if (pointer == NULL)
480 		return (0);
481 	ssym = *(caddr_t *)pointer;
482 	pointer = preload_search_info(ef->modptr,
483 	    MODINFO_METADATA | MODINFOMD_ESYM);
484 	if (pointer == NULL)
485 		return (0);
486 	esym = *(caddr_t *)pointer;
487 
488 	base = ssym;
489 
490 	symcnt = *(long *)base;
491 	base += sizeof(long);
492 	symtab = (Elf_Sym *)base;
493 	base += roundup(symcnt, sizeof(long));
494 
495 	if (base > esym || base < ssym) {
496 		printf("Symbols are corrupt!\n");
497 		return (EINVAL);
498 	}
499 
500 	strcnt = *(long *)base;
501 	base += sizeof(long);
502 	strtab = base;
503 	base += roundup(strcnt, sizeof(long));
504 
505 	if (base > esym || base < ssym) {
506 		printf("Symbols are corrupt!\n");
507 		return (EINVAL);
508 	}
509 
510 	ef->ddbsymtab = symtab;
511 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
512 	ef->ddbstrtab = strtab;
513 	ef->ddbstrcnt = strcnt;
514 
515 	return (0);
516 }
517 
518 static int
519 parse_dynamic(elf_file_t ef)
520 {
521 	Elf_Dyn *dp;
522 	int plttype = DT_REL;
523 
524 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
525 		switch (dp->d_tag) {
526 		case DT_HASH:
527 		{
528 			/* From src/libexec/rtld-elf/rtld.c */
529 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
530 			    (ef->address + dp->d_un.d_ptr);
531 			ef->nbuckets = hashtab[0];
532 			ef->nchains = hashtab[1];
533 			ef->buckets = hashtab + 2;
534 			ef->chains = ef->buckets + ef->nbuckets;
535 			break;
536 		}
537 		case DT_STRTAB:
538 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
539 			break;
540 		case DT_STRSZ:
541 			ef->strsz = dp->d_un.d_val;
542 			break;
543 		case DT_SYMTAB:
544 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
545 			break;
546 		case DT_SYMENT:
547 			if (dp->d_un.d_val != sizeof(Elf_Sym))
548 				return (ENOEXEC);
549 			break;
550 		case DT_PLTGOT:
551 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
552 			break;
553 		case DT_REL:
554 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
555 			break;
556 		case DT_RELSZ:
557 			ef->relsize = dp->d_un.d_val;
558 			break;
559 		case DT_RELENT:
560 			if (dp->d_un.d_val != sizeof(Elf_Rel))
561 				return (ENOEXEC);
562 			break;
563 		case DT_JMPREL:
564 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
565 			break;
566 		case DT_PLTRELSZ:
567 			ef->pltrelsize = dp->d_un.d_val;
568 			break;
569 		case DT_RELA:
570 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
571 			break;
572 		case DT_RELASZ:
573 			ef->relasize = dp->d_un.d_val;
574 			break;
575 		case DT_RELAENT:
576 			if (dp->d_un.d_val != sizeof(Elf_Rela))
577 				return (ENOEXEC);
578 			break;
579 		case DT_PLTREL:
580 			plttype = dp->d_un.d_val;
581 			if (plttype != DT_REL && plttype != DT_RELA)
582 				return (ENOEXEC);
583 			break;
584 #ifdef GDB
585 		case DT_DEBUG:
586 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
587 			break;
588 #endif
589 		}
590 	}
591 
592 	if (plttype == DT_RELA) {
593 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
594 		ef->pltrel = NULL;
595 		ef->pltrelasize = ef->pltrelsize;
596 		ef->pltrelsize = 0;
597 	}
598 
599 	ef->ddbsymtab = ef->symtab;
600 	ef->ddbsymcnt = ef->nchains;
601 	ef->ddbstrtab = ef->strtab;
602 	ef->ddbstrcnt = ef->strsz;
603 
604 	return (0);
605 }
606 
607 static int
608 parse_dpcpu(elf_file_t ef)
609 {
610 	int count;
611 	int error;
612 
613 	ef->pcpu_start = 0;
614 	ef->pcpu_stop = 0;
615 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
616 	    (void ***)&ef->pcpu_stop, &count);
617 	/* Error just means there is no pcpu set to relocate. */
618 	if (error != 0)
619 		return (0);
620 	count *= sizeof(void *);
621 	/*
622 	 * Allocate space in the primary pcpu area.  Copy in our
623 	 * initialization from the data section and then initialize
624 	 * all per-cpu storage from that.
625 	 */
626 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
627 	if (ef->pcpu_base == 0)
628 		return (ENOSPC);
629 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
630 	dpcpu_copy((void *)ef->pcpu_base, count);
631 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
632 	    ef->pcpu_base);
633 
634 	return (0);
635 }
636 
637 #ifdef VIMAGE
638 static int
639 parse_vnet(elf_file_t ef)
640 {
641 	int count;
642 	int error;
643 
644 	ef->vnet_start = 0;
645 	ef->vnet_stop = 0;
646 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
647 	    (void ***)&ef->vnet_stop, &count);
648 	/* Error just means there is no vnet data set to relocate. */
649 	if (error != 0)
650 		return (0);
651 	count *= sizeof(void *);
652 	/*
653 	 * Allocate space in the primary vnet area.  Copy in our
654 	 * initialization from the data section and then initialize
655 	 * all per-vnet storage from that.
656 	 */
657 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
658 	if (ef->vnet_base == 0)
659 		return (ENOSPC);
660 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
661 	vnet_data_copy((void *)ef->vnet_base, count);
662 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
663 	    ef->vnet_base);
664 
665 	return (0);
666 }
667 #endif
668 
669 static int
670 link_elf_link_preload(linker_class_t cls,
671     const char* filename, linker_file_t *result)
672 {
673 	Elf_Addr *ctors_addrp;
674 	Elf_Size *ctors_sizep;
675 	caddr_t modptr, baseptr, sizeptr, dynptr;
676 	char *type;
677 	elf_file_t ef;
678 	linker_file_t lf;
679 	int error;
680 	vm_offset_t dp;
681 
682 	/* Look to see if we have the file preloaded */
683 	modptr = preload_search_by_name(filename);
684 	if (modptr == NULL)
685 		return (ENOENT);
686 
687 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
688 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
689 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
690 	dynptr = preload_search_info(modptr,
691 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
692 	if (type == NULL ||
693 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
694 	     strcmp(type, "elf module") != 0))
695 		return (EFTYPE);
696 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
697 		return (EINVAL);
698 
699 	lf = linker_make_file(filename, &link_elf_class);
700 	if (lf == NULL)
701 		return (ENOMEM);
702 
703 	ef = (elf_file_t) lf;
704 	ef->preloaded = 1;
705 	ef->modptr = modptr;
706 	ef->address = *(caddr_t *)baseptr;
707 #ifdef SPARSE_MAPPING
708 	ef->object = 0;
709 #endif
710 	dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
711 	ef->dynamic = (Elf_Dyn *)dp;
712 	lf->address = ef->address;
713 	lf->size = *(size_t *)sizeptr;
714 
715 	ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
716 	    MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
717 	ctors_sizep = (Elf_Size *)preload_search_info(modptr,
718 	    MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
719 	if (ctors_addrp != NULL && ctors_sizep != NULL) {
720 		lf->ctors_addr = ef->address + *ctors_addrp;
721 		lf->ctors_size = *ctors_sizep;
722 	}
723 
724 	error = parse_dynamic(ef);
725 	if (error == 0)
726 		error = parse_dpcpu(ef);
727 #ifdef VIMAGE
728 	if (error == 0)
729 		error = parse_vnet(ef);
730 #endif
731 	if (error != 0) {
732 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
733 		return (error);
734 	}
735 	link_elf_reloc_local(lf);
736 	*result = lf;
737 	return (0);
738 }
739 
740 static int
741 link_elf_link_preload_finish(linker_file_t lf)
742 {
743 	elf_file_t ef;
744 	int error;
745 
746 	ef = (elf_file_t) lf;
747 	error = relocate_file(ef);
748 	if (error != 0)
749 		return (error);
750 	(void)link_elf_preload_parse_symbols(ef);
751 
752 	return (link_elf_link_common_finish(lf));
753 }
754 
755 static int
756 link_elf_load_file(linker_class_t cls, const char* filename,
757     linker_file_t* result)
758 {
759 	struct nameidata nd;
760 	struct thread* td = curthread;	/* XXX */
761 	Elf_Ehdr *hdr;
762 	caddr_t firstpage;
763 	int nbytes, i;
764 	Elf_Phdr *phdr;
765 	Elf_Phdr *phlimit;
766 	Elf_Phdr *segs[MAXSEGS];
767 	int nsegs;
768 	Elf_Phdr *phdyn;
769 	Elf_Phdr *phphdr;
770 	caddr_t mapbase;
771 	size_t mapsize;
772 	Elf_Off base_offset;
773 	Elf_Addr base_vaddr;
774 	Elf_Addr base_vlimit;
775 	int error = 0;
776 	ssize_t resid;
777 	int flags;
778 	elf_file_t ef;
779 	linker_file_t lf;
780 	Elf_Shdr *shdr;
781 	int symtabindex;
782 	int symstrindex;
783 	int shstrindex;
784 	int symcnt;
785 	int strcnt;
786 	char *shstrs;
787 
788 	shdr = NULL;
789 	lf = NULL;
790 	shstrs = NULL;
791 
792 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
793 	flags = FREAD;
794 	error = vn_open(&nd, &flags, 0, NULL);
795 	if (error != 0)
796 		return (error);
797 	NDFREE(&nd, NDF_ONLY_PNBUF);
798 	if (nd.ni_vp->v_type != VREG) {
799 		error = ENOEXEC;
800 		firstpage = NULL;
801 		goto out;
802 	}
803 #ifdef MAC
804 	error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
805 	if (error != 0) {
806 		firstpage = NULL;
807 		goto out;
808 	}
809 #endif
810 
811 	/*
812 	 * Read the elf header from the file.
813 	 */
814 	firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
815 	hdr = (Elf_Ehdr *)firstpage;
816 	error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
817 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
818 	    &resid, td);
819 	nbytes = PAGE_SIZE - resid;
820 	if (error != 0)
821 		goto out;
822 
823 	if (!IS_ELF(*hdr)) {
824 		error = ENOEXEC;
825 		goto out;
826 	}
827 
828 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
829 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
830 		link_elf_error(filename, "Unsupported file layout");
831 		error = ENOEXEC;
832 		goto out;
833 	}
834 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
835 	    hdr->e_version != EV_CURRENT) {
836 		link_elf_error(filename, "Unsupported file version");
837 		error = ENOEXEC;
838 		goto out;
839 	}
840 	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
841 		error = ENOSYS;
842 		goto out;
843 	}
844 	if (hdr->e_machine != ELF_TARG_MACH) {
845 		link_elf_error(filename, "Unsupported machine");
846 		error = ENOEXEC;
847 		goto out;
848 	}
849 
850 	/*
851 	 * We rely on the program header being in the first page.
852 	 * This is not strictly required by the ABI specification, but
853 	 * it seems to always true in practice.  And, it simplifies
854 	 * things considerably.
855 	 */
856 	if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
857 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
858 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
859 		link_elf_error(filename, "Unreadable program headers");
860 
861 	/*
862 	 * Scan the program header entries, and save key information.
863 	 *
864 	 * We rely on there being exactly two load segments, text and data,
865 	 * in that order.
866 	 */
867 	phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
868 	phlimit = phdr + hdr->e_phnum;
869 	nsegs = 0;
870 	phdyn = NULL;
871 	phphdr = NULL;
872 	while (phdr < phlimit) {
873 		switch (phdr->p_type) {
874 		case PT_LOAD:
875 			if (nsegs == MAXSEGS) {
876 				link_elf_error(filename, "Too many sections");
877 				error = ENOEXEC;
878 				goto out;
879 			}
880 			/*
881 			 * XXX: We just trust they come in right order ??
882 			 */
883 			segs[nsegs] = phdr;
884 			++nsegs;
885 			break;
886 
887 		case PT_PHDR:
888 			phphdr = phdr;
889 			break;
890 
891 		case PT_DYNAMIC:
892 			phdyn = phdr;
893 			break;
894 
895 		case PT_INTERP:
896 			error = ENOSYS;
897 			goto out;
898 		}
899 
900 		++phdr;
901 	}
902 	if (phdyn == NULL) {
903 		link_elf_error(filename, "Object is not dynamically-linked");
904 		error = ENOEXEC;
905 		goto out;
906 	}
907 	if (nsegs == 0) {
908 		link_elf_error(filename, "No sections");
909 		error = ENOEXEC;
910 		goto out;
911 	}
912 
913 	/*
914 	 * Allocate the entire address space of the object, to stake
915 	 * out our contiguous region, and to establish the base
916 	 * address for relocation.
917 	 */
918 	base_offset = trunc_page(segs[0]->p_offset);
919 	base_vaddr = trunc_page(segs[0]->p_vaddr);
920 	base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
921 	    segs[nsegs - 1]->p_memsz);
922 	mapsize = base_vlimit - base_vaddr;
923 
924 	lf = linker_make_file(filename, &link_elf_class);
925 	if (lf == NULL) {
926 		error = ENOMEM;
927 		goto out;
928 	}
929 
930 	ef = (elf_file_t) lf;
931 #ifdef SPARSE_MAPPING
932 	ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
933 	if (ef->object == NULL) {
934 		error = ENOMEM;
935 		goto out;
936 	}
937 	ef->address = (caddr_t) vm_map_min(kernel_map);
938 	error = vm_map_find(kernel_map, ef->object, 0,
939 	    (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE,
940 	    VM_PROT_ALL, VM_PROT_ALL, 0);
941 	if (error != 0) {
942 		vm_object_deallocate(ef->object);
943 		ef->object = 0;
944 		goto out;
945 	}
946 #else
947 	ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
948 #endif
949 	mapbase = ef->address;
950 
951 	/*
952 	 * Read the text and data sections and zero the bss.
953 	 */
954 	for (i = 0; i < nsegs; i++) {
955 		caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
956 		error = vn_rdwr(UIO_READ, nd.ni_vp,
957 		    segbase, segs[i]->p_filesz, segs[i]->p_offset,
958 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
959 		    &resid, td);
960 		if (error != 0)
961 			goto out;
962 		bzero(segbase + segs[i]->p_filesz,
963 		    segs[i]->p_memsz - segs[i]->p_filesz);
964 
965 #ifdef SPARSE_MAPPING
966 		/*
967 		 * Wire down the pages
968 		 */
969 		error = vm_map_wire(kernel_map,
970 		    (vm_offset_t) segbase,
971 		    (vm_offset_t) segbase + segs[i]->p_memsz,
972 		    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
973 		if (error != KERN_SUCCESS) {
974 			error = ENOMEM;
975 			goto out;
976 		}
977 #endif
978 	}
979 
980 #ifdef GPROF
981 	/* Update profiling information with the new text segment. */
982 	mtx_lock(&Giant);
983 	kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
984 	    segs[0]->p_memsz));
985 	mtx_unlock(&Giant);
986 #endif
987 
988 	ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
989 
990 	lf->address = ef->address;
991 	lf->size = mapsize;
992 
993 	error = parse_dynamic(ef);
994 	if (error != 0)
995 		goto out;
996 	error = parse_dpcpu(ef);
997 	if (error != 0)
998 		goto out;
999 #ifdef VIMAGE
1000 	error = parse_vnet(ef);
1001 	if (error != 0)
1002 		goto out;
1003 #endif
1004 	link_elf_reloc_local(lf);
1005 
1006 	VOP_UNLOCK(nd.ni_vp, 0);
1007 	error = linker_load_dependencies(lf);
1008 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1009 	if (error != 0)
1010 		goto out;
1011 	error = relocate_file(ef);
1012 	if (error != 0)
1013 		goto out;
1014 
1015 	/*
1016 	 * Try and load the symbol table if it's present.  (you can
1017 	 * strip it!)
1018 	 */
1019 	nbytes = hdr->e_shnum * hdr->e_shentsize;
1020 	if (nbytes == 0 || hdr->e_shoff == 0)
1021 		goto nosyms;
1022 	shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1023 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1024 	    (caddr_t)shdr, nbytes, hdr->e_shoff,
1025 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1026 	    &resid, td);
1027 	if (error != 0)
1028 		goto out;
1029 
1030 	/* Read section string table */
1031 	shstrindex = hdr->e_shstrndx;
1032 	if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1033 	    shdr[shstrindex].sh_size != 0) {
1034 		nbytes = shdr[shstrindex].sh_size;
1035 		shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1036 		error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1037 		    shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1038 		    td->td_ucred, NOCRED, &resid, td);
1039 		if (error)
1040 			goto out;
1041 	}
1042 
1043 	symtabindex = -1;
1044 	symstrindex = -1;
1045 	for (i = 0; i < hdr->e_shnum; i++) {
1046 		if (shdr[i].sh_type == SHT_SYMTAB) {
1047 			symtabindex = i;
1048 			symstrindex = shdr[i].sh_link;
1049 		} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1050 		    strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1051 			/* Record relocated address and size of .ctors. */
1052 			lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1053 			lf->ctors_size = shdr[i].sh_size;
1054 		}
1055 	}
1056 	if (symtabindex < 0 || symstrindex < 0)
1057 		goto nosyms;
1058 
1059 	symcnt = shdr[symtabindex].sh_size;
1060 	ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1061 	strcnt = shdr[symstrindex].sh_size;
1062 	ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1063 
1064 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1065 	    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1066 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1067 	    &resid, td);
1068 	if (error != 0)
1069 		goto out;
1070 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1071 	    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1072 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1073 	    &resid, td);
1074 	if (error != 0)
1075 		goto out;
1076 
1077 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1078 	ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1079 	ef->ddbstrcnt = strcnt;
1080 	ef->ddbstrtab = ef->strbase;
1081 
1082 nosyms:
1083 	error = link_elf_link_common_finish(lf);
1084 	if (error != 0)
1085 		goto out;
1086 
1087 	*result = lf;
1088 
1089 out:
1090 	VOP_UNLOCK(nd.ni_vp, 0);
1091 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1092 	if (error != 0 && lf != NULL)
1093 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1094 	if (shdr != NULL)
1095 		free(shdr, M_LINKER);
1096 	if (firstpage != NULL)
1097 		free(firstpage, M_LINKER);
1098 	if (shstrs != NULL)
1099 		free(shstrs, M_LINKER);
1100 
1101 	return (error);
1102 }
1103 
1104 Elf_Addr
1105 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1106 {
1107 	elf_file_t ef;
1108 
1109 	ef = (elf_file_t)lf;
1110 	if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1111 		return ((x - ef->pcpu_start) + ef->pcpu_base);
1112 #ifdef VIMAGE
1113 	if (x >= ef->vnet_start && x < ef->vnet_stop)
1114 		return ((x - ef->vnet_start) + ef->vnet_base);
1115 #endif
1116 	return (x);
1117 }
1118 
1119 
1120 static void
1121 link_elf_unload_file(linker_file_t file)
1122 {
1123 	elf_file_t ef = (elf_file_t) file;
1124 
1125 	if (ef->pcpu_base != 0) {
1126 		dpcpu_free((void *)ef->pcpu_base,
1127 		    ef->pcpu_stop - ef->pcpu_start);
1128 		elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1129 	}
1130 #ifdef VIMAGE
1131 	if (ef->vnet_base != 0) {
1132 		vnet_data_free((void *)ef->vnet_base,
1133 		    ef->vnet_stop - ef->vnet_start);
1134 		elf_set_delete(&set_vnet_list, ef->vnet_start);
1135 	}
1136 #endif
1137 #ifdef GDB
1138 	if (ef->gdb.l_ld != NULL) {
1139 		GDB_STATE(RT_DELETE);
1140 		free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1141 		link_elf_delete_gdb(&ef->gdb);
1142 		GDB_STATE(RT_CONSISTENT);
1143 	}
1144 #endif
1145 
1146 	/* Notify MD code that a module is being unloaded. */
1147 	elf_cpu_unload_file(file);
1148 
1149 	if (ef->preloaded) {
1150 		link_elf_unload_preload(file);
1151 		return;
1152 	}
1153 
1154 #ifdef SPARSE_MAPPING
1155 	if (ef->object != NULL) {
1156 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1157 		    (vm_offset_t) ef->address
1158 		    + (ef->object->size << PAGE_SHIFT));
1159 	}
1160 #else
1161 	if (ef->address != NULL)
1162 		free(ef->address, M_LINKER);
1163 #endif
1164 	if (ef->symbase != NULL)
1165 		free(ef->symbase, M_LINKER);
1166 	if (ef->strbase != NULL)
1167 		free(ef->strbase, M_LINKER);
1168 	if (ef->ctftab != NULL)
1169 		free(ef->ctftab, M_LINKER);
1170 	if (ef->ctfoff != NULL)
1171 		free(ef->ctfoff, M_LINKER);
1172 	if (ef->typoff != NULL)
1173 		free(ef->typoff, M_LINKER);
1174 }
1175 
1176 static void
1177 link_elf_unload_preload(linker_file_t file)
1178 {
1179 	if (file->filename != NULL)
1180 		preload_delete_name(file->filename);
1181 }
1182 
1183 static const char *
1184 symbol_name(elf_file_t ef, Elf_Size r_info)
1185 {
1186 	const Elf_Sym *ref;
1187 
1188 	if (ELF_R_SYM(r_info)) {
1189 		ref = ef->symtab + ELF_R_SYM(r_info);
1190 		return (ef->strtab + ref->st_name);
1191 	}
1192 	return (NULL);
1193 }
1194 
1195 static int
1196 relocate_file(elf_file_t ef)
1197 {
1198 	const Elf_Rel *rellim;
1199 	const Elf_Rel *rel;
1200 	const Elf_Rela *relalim;
1201 	const Elf_Rela *rela;
1202 	const char *symname;
1203 
1204 	/* Perform relocations without addend if there are any: */
1205 	rel = ef->rel;
1206 	if (rel != NULL) {
1207 		rellim = (const Elf_Rel *)
1208 		    ((const char *)ef->rel + ef->relsize);
1209 		while (rel < rellim) {
1210 			if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1211 			    ELF_RELOC_REL, elf_lookup)) {
1212 				symname = symbol_name(ef, rel->r_info);
1213 				printf("link_elf: symbol %s undefined\n", symname);
1214 				return (ENOENT);
1215 			}
1216 			rel++;
1217 		}
1218 	}
1219 
1220 	/* Perform relocations with addend if there are any: */
1221 	rela = ef->rela;
1222 	if (rela != NULL) {
1223 		relalim = (const Elf_Rela *)
1224 		    ((const char *)ef->rela + ef->relasize);
1225 		while (rela < relalim) {
1226 			if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1227 			    ELF_RELOC_RELA, elf_lookup)) {
1228 				symname = symbol_name(ef, rela->r_info);
1229 				printf("link_elf: symbol %s undefined\n",
1230 				    symname);
1231 				return (ENOENT);
1232 			}
1233 			rela++;
1234 		}
1235 	}
1236 
1237 	/* Perform PLT relocations without addend if there are any: */
1238 	rel = ef->pltrel;
1239 	if (rel != NULL) {
1240 		rellim = (const Elf_Rel *)
1241 		    ((const char *)ef->pltrel + ef->pltrelsize);
1242 		while (rel < rellim) {
1243 			if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1244 			    ELF_RELOC_REL, elf_lookup)) {
1245 				symname = symbol_name(ef, rel->r_info);
1246 				printf("link_elf: symbol %s undefined\n",
1247 				    symname);
1248 				return (ENOENT);
1249 			}
1250 			rel++;
1251 		}
1252 	}
1253 
1254 	/* Perform relocations with addend if there are any: */
1255 	rela = ef->pltrela;
1256 	if (rela != NULL) {
1257 		relalim = (const Elf_Rela *)
1258 		    ((const char *)ef->pltrela + ef->pltrelasize);
1259 		while (rela < relalim) {
1260 			if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1261 			    ELF_RELOC_RELA, elf_lookup)) {
1262 				symname = symbol_name(ef, rela->r_info);
1263 				printf("link_elf: symbol %s undefined\n",
1264 				    symname);
1265 				return (ENOENT);
1266 			}
1267 			rela++;
1268 		}
1269 	}
1270 
1271 	return (0);
1272 }
1273 
1274 /*
1275  * Hash function for symbol table lookup.  Don't even think about changing
1276  * this.  It is specified by the System V ABI.
1277  */
1278 static unsigned long
1279 elf_hash(const char *name)
1280 {
1281 	const unsigned char *p = (const unsigned char *) name;
1282 	unsigned long h = 0;
1283 	unsigned long g;
1284 
1285 	while (*p != '\0') {
1286 		h = (h << 4) + *p++;
1287 		if ((g = h & 0xf0000000) != 0)
1288 			h ^= g >> 24;
1289 		h &= ~g;
1290 	}
1291 	return (h);
1292 }
1293 
1294 static int
1295 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1296 {
1297 	elf_file_t ef = (elf_file_t) lf;
1298 	unsigned long symnum;
1299 	const Elf_Sym* symp;
1300 	const char *strp;
1301 	unsigned long hash;
1302 	int i;
1303 
1304 	/* If we don't have a hash, bail. */
1305 	if (ef->buckets == NULL || ef->nbuckets == 0) {
1306 		printf("link_elf_lookup_symbol: missing symbol hash table\n");
1307 		return (ENOENT);
1308 	}
1309 
1310 	/* First, search hashed global symbols */
1311 	hash = elf_hash(name);
1312 	symnum = ef->buckets[hash % ef->nbuckets];
1313 
1314 	while (symnum != STN_UNDEF) {
1315 		if (symnum >= ef->nchains) {
1316 			printf("%s: corrupt symbol table\n", __func__);
1317 			return (ENOENT);
1318 		}
1319 
1320 		symp = ef->symtab + symnum;
1321 		if (symp->st_name == 0) {
1322 			printf("%s: corrupt symbol table\n", __func__);
1323 			return (ENOENT);
1324 		}
1325 
1326 		strp = ef->strtab + symp->st_name;
1327 
1328 		if (strcmp(name, strp) == 0) {
1329 			if (symp->st_shndx != SHN_UNDEF ||
1330 			    (symp->st_value != 0 &&
1331 			     ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1332 				*sym = (c_linker_sym_t) symp;
1333 				return (0);
1334 			}
1335 			return (ENOENT);
1336 		}
1337 
1338 		symnum = ef->chains[symnum];
1339 	}
1340 
1341 	/* If we have not found it, look at the full table (if loaded) */
1342 	if (ef->symtab == ef->ddbsymtab)
1343 		return (ENOENT);
1344 
1345 	/* Exhaustive search */
1346 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1347 		strp = ef->ddbstrtab + symp->st_name;
1348 		if (strcmp(name, strp) == 0) {
1349 			if (symp->st_shndx != SHN_UNDEF ||
1350 			    (symp->st_value != 0 &&
1351 			     ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1352 				*sym = (c_linker_sym_t) symp;
1353 				return (0);
1354 			}
1355 			return (ENOENT);
1356 		}
1357 	}
1358 
1359 	return (ENOENT);
1360 }
1361 
1362 static int
1363 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1364     linker_symval_t *symval)
1365 {
1366 	elf_file_t ef = (elf_file_t) lf;
1367 	const Elf_Sym* es = (const Elf_Sym*) sym;
1368 
1369 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1370 		symval->name = ef->strtab + es->st_name;
1371 		symval->value = (caddr_t) ef->address + es->st_value;
1372 		symval->size = es->st_size;
1373 		return (0);
1374 	}
1375 	if (ef->symtab == ef->ddbsymtab)
1376 		return (ENOENT);
1377 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1378 		symval->name = ef->ddbstrtab + es->st_name;
1379 		symval->value = (caddr_t) ef->address + es->st_value;
1380 		symval->size = es->st_size;
1381 		return (0);
1382 	}
1383 	return (ENOENT);
1384 }
1385 
1386 static int
1387 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1388     c_linker_sym_t *sym, long *diffp)
1389 {
1390 	elf_file_t ef = (elf_file_t) lf;
1391 	u_long off = (uintptr_t) (void *) value;
1392 	u_long diff = off;
1393 	u_long st_value;
1394 	const Elf_Sym* es;
1395 	const Elf_Sym* best = 0;
1396 	int i;
1397 
1398 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1399 		if (es->st_name == 0)
1400 			continue;
1401 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1402 		if (off >= st_value) {
1403 			if (off - st_value < diff) {
1404 				diff = off - st_value;
1405 				best = es;
1406 				if (diff == 0)
1407 					break;
1408 			} else if (off - st_value == diff) {
1409 				best = es;
1410 			}
1411 		}
1412 	}
1413 	if (best == 0)
1414 		*diffp = off;
1415 	else
1416 		*diffp = diff;
1417 	*sym = (c_linker_sym_t) best;
1418 
1419 	return (0);
1420 }
1421 
1422 /*
1423  * Look up a linker set on an ELF system.
1424  */
1425 static int
1426 link_elf_lookup_set(linker_file_t lf, const char *name,
1427     void ***startp, void ***stopp, int *countp)
1428 {
1429 	c_linker_sym_t sym;
1430 	linker_symval_t symval;
1431 	char *setsym;
1432 	void **start, **stop;
1433 	int len, error = 0, count;
1434 
1435 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1436 	setsym = malloc(len, M_LINKER, M_WAITOK);
1437 
1438 	/* get address of first entry */
1439 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1440 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1441 	if (error != 0)
1442 		goto out;
1443 	link_elf_symbol_values(lf, sym, &symval);
1444 	if (symval.value == 0) {
1445 		error = ESRCH;
1446 		goto out;
1447 	}
1448 	start = (void **)symval.value;
1449 
1450 	/* get address of last entry */
1451 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1452 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1453 	if (error != 0)
1454 		goto out;
1455 	link_elf_symbol_values(lf, sym, &symval);
1456 	if (symval.value == 0) {
1457 		error = ESRCH;
1458 		goto out;
1459 	}
1460 	stop = (void **)symval.value;
1461 
1462 	/* and the number of entries */
1463 	count = stop - start;
1464 
1465 	/* and copy out */
1466 	if (startp != NULL)
1467 		*startp = start;
1468 	if (stopp != NULL)
1469 		*stopp = stop;
1470 	if (countp != NULL)
1471 		*countp = count;
1472 
1473 out:
1474 	free(setsym, M_LINKER);
1475 	return (error);
1476 }
1477 
1478 static int
1479 link_elf_each_function_name(linker_file_t file,
1480   int (*callback)(const char *, void *), void *opaque)
1481 {
1482 	elf_file_t ef = (elf_file_t)file;
1483 	const Elf_Sym *symp;
1484 	int i, error;
1485 
1486 	/* Exhaustive search */
1487 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1488 		if (symp->st_value != 0 &&
1489 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1490 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1491 			if (error != 0)
1492 				return (error);
1493 		}
1494 	}
1495 	return (0);
1496 }
1497 
1498 static int
1499 link_elf_each_function_nameval(linker_file_t file,
1500     linker_function_nameval_callback_t callback, void *opaque)
1501 {
1502 	linker_symval_t symval;
1503 	elf_file_t ef = (elf_file_t)file;
1504 	const Elf_Sym* symp;
1505 	int i, error;
1506 
1507 	/* Exhaustive search */
1508 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1509 		if (symp->st_value != 0 &&
1510 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1511 			error = link_elf_symbol_values(file,
1512 			    (c_linker_sym_t) symp, &symval);
1513 			if (error != 0)
1514 				return (error);
1515 			error = callback(file, i, &symval, opaque);
1516 			if (error != 0)
1517 				return (error);
1518 		}
1519 	}
1520 	return (0);
1521 }
1522 
1523 const Elf_Sym *
1524 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1525 {
1526 	elf_file_t ef = (elf_file_t)lf;
1527 
1528 	if (symidx >= ef->nchains)
1529 		return (NULL);
1530 	return (ef->symtab + symidx);
1531 }
1532 
1533 const char *
1534 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1535 {
1536 	elf_file_t ef = (elf_file_t)lf;
1537 	const Elf_Sym *sym;
1538 
1539 	if (symidx >= ef->nchains)
1540 		return (NULL);
1541 	sym = ef->symtab + symidx;
1542 	return (ef->strtab + sym->st_name);
1543 }
1544 
1545 /*
1546  * Symbol lookup function that can be used when the symbol index is known (ie
1547  * in relocations). It uses the symbol index instead of doing a fully fledged
1548  * hash table based lookup when such is valid. For example for local symbols.
1549  * This is not only more efficient, it's also more correct. It's not always
1550  * the case that the symbol can be found through the hash table.
1551  */
1552 static Elf_Addr
1553 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1554 {
1555 	elf_file_t ef = (elf_file_t)lf;
1556 	const Elf_Sym *sym;
1557 	const char *symbol;
1558 	Elf_Addr addr, start, base;
1559 
1560 	/* Don't even try to lookup the symbol if the index is bogus. */
1561 	if (symidx >= ef->nchains)
1562 		return (0);
1563 
1564 	sym = ef->symtab + symidx;
1565 
1566 	/*
1567 	 * Don't do a full lookup when the symbol is local. It may even
1568 	 * fail because it may not be found through the hash table.
1569 	 */
1570 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1571 		/* Force lookup failure when we have an insanity. */
1572 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1573 			return (0);
1574 		return ((Elf_Addr)ef->address + sym->st_value);
1575 	}
1576 
1577 	/*
1578 	 * XXX we can avoid doing a hash table based lookup for global
1579 	 * symbols as well. This however is not always valid, so we'll
1580 	 * just do it the hard way for now. Performance tweaks can
1581 	 * always be added.
1582 	 */
1583 
1584 	symbol = ef->strtab + sym->st_name;
1585 
1586 	/* Force a lookup failure if the symbol name is bogus. */
1587 	if (*symbol == 0)
1588 		return (0);
1589 
1590 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1591 
1592 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1593 		addr = addr - start + base;
1594 #ifdef VIMAGE
1595 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1596 		addr = addr - start + base;
1597 #endif
1598 	return addr;
1599 }
1600 
1601 static void
1602 link_elf_reloc_local(linker_file_t lf)
1603 {
1604 	const Elf_Rel *rellim;
1605 	const Elf_Rel *rel;
1606 	const Elf_Rela *relalim;
1607 	const Elf_Rela *rela;
1608 	elf_file_t ef = (elf_file_t)lf;
1609 
1610 	/* Perform relocations without addend if there are any: */
1611 	if ((rel = ef->rel) != NULL) {
1612 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1613 		while (rel < rellim) {
1614 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1615 			    ELF_RELOC_REL, elf_lookup);
1616 			rel++;
1617 		}
1618 	}
1619 
1620 	/* Perform relocations with addend if there are any: */
1621 	if ((rela = ef->rela) != NULL) {
1622 		relalim = (const Elf_Rela *)
1623 		    ((const char *)ef->rela + ef->relasize);
1624 		while (rela < relalim) {
1625 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1626 			    ELF_RELOC_RELA, elf_lookup);
1627 			rela++;
1628 		}
1629 	}
1630 }
1631 
1632 static long
1633 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1634 {
1635 	elf_file_t ef = (elf_file_t)lf;
1636 
1637 	*symtab = ef->ddbsymtab;
1638 
1639 	if (*symtab == NULL)
1640 		return (0);
1641 
1642 	return (ef->ddbsymcnt);
1643 }
1644 
1645 static long
1646 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1647 {
1648 	elf_file_t ef = (elf_file_t)lf;
1649 
1650 	*strtab = ef->ddbstrtab;
1651 
1652 	if (*strtab == NULL)
1653 		return (0);
1654 
1655 	return (ef->ddbstrcnt);
1656 }
1657