xref: /freebsd/sys/kern/link_elf.c (revision 47dd1d1b619cc035b82b49a91a25544309ff95ae)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1998-2000 Doug Rabson
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_ddb.h"
33 #include "opt_gdb.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #ifdef GPROF
38 #include <sys/gmon.h>
39 #endif
40 #include <sys/kernel.h>
41 #include <sys/lock.h>
42 #include <sys/malloc.h>
43 #include <sys/mutex.h>
44 #include <sys/mount.h>
45 #include <sys/pcpu.h>
46 #include <sys/proc.h>
47 #include <sys/namei.h>
48 #include <sys/fcntl.h>
49 #include <sys/vnode.h>
50 #include <sys/linker.h>
51 
52 #include <machine/elf.h>
53 
54 #include <net/vnet.h>
55 
56 #include <security/mac/mac_framework.h>
57 
58 #include <vm/vm.h>
59 #include <vm/vm_param.h>
60 #ifdef SPARSE_MAPPING
61 #include <vm/vm_object.h>
62 #include <vm/vm_kern.h>
63 #include <vm/vm_extern.h>
64 #endif
65 #include <vm/pmap.h>
66 #include <vm/vm_map.h>
67 
68 #include <sys/link_elf.h>
69 
70 #ifdef DDB_CTF
71 #include <sys/zlib.h>
72 #endif
73 
74 #include "linker_if.h"
75 
76 #define MAXSEGS 4
77 
78 typedef struct elf_file {
79 	struct linker_file lf;		/* Common fields */
80 	int		preloaded;	/* Was file pre-loaded */
81 	caddr_t		address;	/* Relocation address */
82 #ifdef SPARSE_MAPPING
83 	vm_object_t	object;		/* VM object to hold file pages */
84 #endif
85 	Elf_Dyn		*dynamic;	/* Symbol table etc. */
86 	Elf_Hashelt	nbuckets;	/* DT_HASH info */
87 	Elf_Hashelt	nchains;
88 	const Elf_Hashelt *buckets;
89 	const Elf_Hashelt *chains;
90 	caddr_t		hash;
91 	caddr_t		strtab;		/* DT_STRTAB */
92 	int		strsz;		/* DT_STRSZ */
93 	const Elf_Sym	*symtab;		/* DT_SYMTAB */
94 	Elf_Addr	*got;		/* DT_PLTGOT */
95 	const Elf_Rel	*pltrel;	/* DT_JMPREL */
96 	int		pltrelsize;	/* DT_PLTRELSZ */
97 	const Elf_Rela	*pltrela;	/* DT_JMPREL */
98 	int		pltrelasize;	/* DT_PLTRELSZ */
99 	const Elf_Rel	*rel;		/* DT_REL */
100 	int		relsize;	/* DT_RELSZ */
101 	const Elf_Rela	*rela;		/* DT_RELA */
102 	int		relasize;	/* DT_RELASZ */
103 	caddr_t		modptr;
104 	const Elf_Sym	*ddbsymtab;	/* The symbol table we are using */
105 	long		ddbsymcnt;	/* Number of symbols */
106 	caddr_t		ddbstrtab;	/* String table */
107 	long		ddbstrcnt;	/* number of bytes in string table */
108 	caddr_t		symbase;	/* malloc'ed symbold base */
109 	caddr_t		strbase;	/* malloc'ed string base */
110 	caddr_t		ctftab;		/* CTF table */
111 	long		ctfcnt;		/* number of bytes in CTF table */
112 	caddr_t		ctfoff;		/* CTF offset table */
113 	caddr_t		typoff;		/* Type offset table */
114 	long		typlen;		/* Number of type entries. */
115 	Elf_Addr	pcpu_start;	/* Pre-relocation pcpu set start. */
116 	Elf_Addr	pcpu_stop;	/* Pre-relocation pcpu set stop. */
117 	Elf_Addr	pcpu_base;	/* Relocated pcpu set address. */
118 #ifdef VIMAGE
119 	Elf_Addr	vnet_start;	/* Pre-relocation vnet set start. */
120 	Elf_Addr	vnet_stop;	/* Pre-relocation vnet set stop. */
121 	Elf_Addr	vnet_base;	/* Relocated vnet set address. */
122 #endif
123 #ifdef GDB
124 	struct link_map	gdb;		/* hooks for gdb */
125 #endif
126 } *elf_file_t;
127 
128 struct elf_set {
129 	Elf_Addr	es_start;
130 	Elf_Addr	es_stop;
131 	Elf_Addr	es_base;
132 	TAILQ_ENTRY(elf_set)	es_link;
133 };
134 
135 TAILQ_HEAD(elf_set_head, elf_set);
136 
137 #include <kern/kern_ctf.c>
138 
139 static int	link_elf_link_common_finish(linker_file_t);
140 static int	link_elf_link_preload(linker_class_t cls,
141 				      const char *, linker_file_t *);
142 static int	link_elf_link_preload_finish(linker_file_t);
143 static int	link_elf_load_file(linker_class_t, const char *,
144 		    linker_file_t *);
145 static int	link_elf_lookup_symbol(linker_file_t, const char *,
146 		    c_linker_sym_t *);
147 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
148 		    linker_symval_t *);
149 static int	link_elf_search_symbol(linker_file_t, caddr_t,
150 		    c_linker_sym_t *, long *);
151 
152 static void	link_elf_unload_file(linker_file_t);
153 static void	link_elf_unload_preload(linker_file_t);
154 static int	link_elf_lookup_set(linker_file_t, const char *,
155 		    void ***, void ***, int *);
156 static int	link_elf_each_function_name(linker_file_t,
157 		    int (*)(const char *, void *), void *);
158 static int	link_elf_each_function_nameval(linker_file_t,
159 		    linker_function_nameval_callback_t, void *);
160 static void	link_elf_reloc_local(linker_file_t);
161 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
162 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
163 static int	elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
164 
165 static kobj_method_t link_elf_methods[] = {
166 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
167 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
168 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
169 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
170 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
171 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
172 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
173 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
174 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
175 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
176 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
177 	KOBJMETHOD(linker_symtab_get,		link_elf_symtab_get),
178 	KOBJMETHOD(linker_strtab_get,		link_elf_strtab_get),
179 	{ 0, 0 }
180 };
181 
182 static struct linker_class link_elf_class = {
183 #if ELF_TARG_CLASS == ELFCLASS32
184 	"elf32",
185 #else
186 	"elf64",
187 #endif
188 	link_elf_methods, sizeof(struct elf_file)
189 };
190 
191 static int	parse_dynamic(elf_file_t);
192 static int	relocate_file(elf_file_t);
193 static int	relocate_file1(elf_file_t ef, int (*elf_reloc_func)(
194 		    linker_file_t lf, Elf_Addr relocbase, const void *data,
195 		    int type, elf_lookup_fn lookup));
196 static int	link_elf_preload_parse_symbols(elf_file_t);
197 
198 static struct elf_set_head set_pcpu_list;
199 #ifdef VIMAGE
200 static struct elf_set_head set_vnet_list;
201 #endif
202 
203 static void
204 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
205 {
206 	struct elf_set *set, *iter;
207 
208 	set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
209 	set->es_start = start;
210 	set->es_stop = stop;
211 	set->es_base = base;
212 
213 	TAILQ_FOREACH(iter, list, es_link) {
214 
215 		KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
216 		    (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
217 		    ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
218 		    (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
219 		    (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
220 
221 		if (iter->es_start > set->es_start) {
222 			TAILQ_INSERT_BEFORE(iter, set, es_link);
223 			break;
224 		}
225 	}
226 
227 	if (iter == NULL)
228 		TAILQ_INSERT_TAIL(list, set, es_link);
229 }
230 
231 static int
232 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
233 {
234 	struct elf_set *set;
235 
236 	TAILQ_FOREACH(set, list, es_link) {
237 		if (addr < set->es_start)
238 			return (0);
239 		if (addr < set->es_stop) {
240 			*start = set->es_start;
241 			*base = set->es_base;
242 			return (1);
243 		}
244 	}
245 
246 	return (0);
247 }
248 
249 static void
250 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
251 {
252 	struct elf_set *set;
253 
254 	TAILQ_FOREACH(set, list, es_link) {
255 		if (start < set->es_start)
256 			break;
257 		if (start == set->es_start) {
258 			TAILQ_REMOVE(list, set, es_link);
259 			free(set, M_LINKER);
260 			return;
261 		}
262 	}
263 	KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
264 	    (uintmax_t)start));
265 }
266 
267 #ifdef GDB
268 static void	r_debug_state(struct r_debug *, struct link_map *);
269 
270 /*
271  * A list of loaded modules for GDB to use for loading symbols.
272  */
273 struct r_debug r_debug;
274 
275 #define GDB_STATE(s) do {				\
276 	r_debug.r_state = s; r_debug_state(NULL, NULL);	\
277 } while (0)
278 
279 /*
280  * Function for the debugger to set a breakpoint on to gain control.
281  */
282 static void
283 r_debug_state(struct r_debug *dummy_one __unused,
284 	      struct link_map *dummy_two __unused)
285 {
286 }
287 
288 static void
289 link_elf_add_gdb(struct link_map *l)
290 {
291 	struct link_map *prev;
292 
293 	l->l_next = NULL;
294 
295 	if (r_debug.r_map == NULL) {
296 		/* Add first. */
297 		l->l_prev = NULL;
298 		r_debug.r_map = l;
299 	} else {
300 		/* Append to list. */
301 		for (prev = r_debug.r_map;
302 		    prev->l_next != NULL;
303 		    prev = prev->l_next)
304 			;
305 		l->l_prev = prev;
306 		prev->l_next = l;
307 	}
308 }
309 
310 static void
311 link_elf_delete_gdb(struct link_map *l)
312 {
313 	if (l->l_prev == NULL) {
314 		/* Remove first. */
315 		if ((r_debug.r_map = l->l_next) != NULL)
316 			l->l_next->l_prev = NULL;
317 	} else {
318 		/* Remove any but first. */
319 		if ((l->l_prev->l_next = l->l_next) != NULL)
320 			l->l_next->l_prev = l->l_prev;
321 	}
322 }
323 #endif /* GDB */
324 
325 /*
326  * The kernel symbol table starts here.
327  */
328 extern struct _dynamic _DYNAMIC;
329 
330 static void
331 link_elf_error(const char *filename, const char *s)
332 {
333 	if (filename == NULL)
334 		printf("kldload: %s\n", s);
335 	else
336 		printf("kldload: %s: %s\n", filename, s);
337 }
338 
339 static void
340 link_elf_invoke_ctors(caddr_t addr, size_t size)
341 {
342 	void (**ctor)(void);
343 	size_t i, cnt;
344 
345 	if (addr == NULL || size == 0)
346 		return;
347 	cnt = size / sizeof(*ctor);
348 	ctor = (void *)addr;
349 	for (i = 0; i < cnt; i++) {
350 		if (ctor[i] != NULL)
351 			(*ctor[i])();
352 	}
353 }
354 
355 /*
356  * Actions performed after linking/loading both the preloaded kernel and any
357  * modules; whether preloaded or dynamicly loaded.
358  */
359 static int
360 link_elf_link_common_finish(linker_file_t lf)
361 {
362 #ifdef GDB
363 	elf_file_t ef = (elf_file_t)lf;
364 	char *newfilename;
365 #endif
366 	int error;
367 
368 	/* Notify MD code that a module is being loaded. */
369 	error = elf_cpu_load_file(lf);
370 	if (error != 0)
371 		return (error);
372 
373 #ifdef GDB
374 	GDB_STATE(RT_ADD);
375 	ef->gdb.l_addr = lf->address;
376 	newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
377 	strcpy(newfilename, lf->filename);
378 	ef->gdb.l_name = newfilename;
379 	ef->gdb.l_ld = ef->dynamic;
380 	link_elf_add_gdb(&ef->gdb);
381 	GDB_STATE(RT_CONSISTENT);
382 #endif
383 
384 	/* Invoke .ctors */
385 	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
386 	return (0);
387 }
388 
389 extern vm_offset_t __startkernel, __endkernel;
390 
391 static void
392 link_elf_init(void* arg)
393 {
394 	Elf_Dyn *dp;
395 	Elf_Addr *ctors_addrp;
396 	Elf_Size *ctors_sizep;
397 	caddr_t modptr, baseptr, sizeptr;
398 	elf_file_t ef;
399 	char *modname;
400 
401 	linker_add_class(&link_elf_class);
402 
403 	dp = (Elf_Dyn *)&_DYNAMIC;
404 	modname = NULL;
405 	modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
406 	if (modptr == NULL)
407 		modptr = preload_search_by_type("elf kernel");
408 	modname = (char *)preload_search_info(modptr, MODINFO_NAME);
409 	if (modname == NULL)
410 		modname = "kernel";
411 	linker_kernel_file = linker_make_file(modname, &link_elf_class);
412 	if (linker_kernel_file == NULL)
413 		panic("%s: Can't create linker structures for kernel",
414 		    __func__);
415 
416 	ef = (elf_file_t) linker_kernel_file;
417 	ef->preloaded = 1;
418 #ifdef __powerpc__
419 	ef->address = (caddr_t) (__startkernel - KERNBASE);
420 #else
421 	ef->address = 0;
422 #endif
423 #ifdef SPARSE_MAPPING
424 	ef->object = 0;
425 #endif
426 	ef->dynamic = dp;
427 
428 	if (dp != NULL)
429 		parse_dynamic(ef);
430 #ifdef __powerpc__
431 	linker_kernel_file->address = (caddr_t)__startkernel;
432 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
433 #else
434 	linker_kernel_file->address += KERNBASE;
435 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
436 #endif
437 
438 	if (modptr != NULL) {
439 		ef->modptr = modptr;
440 		baseptr = preload_search_info(modptr, MODINFO_ADDR);
441 		if (baseptr != NULL)
442 			linker_kernel_file->address = *(caddr_t *)baseptr;
443 		sizeptr = preload_search_info(modptr, MODINFO_SIZE);
444 		if (sizeptr != NULL)
445 			linker_kernel_file->size = *(size_t *)sizeptr;
446 		ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
447 			MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
448 		ctors_sizep = (Elf_Size *)preload_search_info(modptr,
449 			MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
450 		if (ctors_addrp != NULL && ctors_sizep != NULL) {
451 			linker_kernel_file->ctors_addr = ef->address +
452 			    *ctors_addrp;
453 			linker_kernel_file->ctors_size = *ctors_sizep;
454 		}
455 	}
456 	(void)link_elf_preload_parse_symbols(ef);
457 
458 #ifdef GDB
459 	r_debug.r_map = NULL;
460 	r_debug.r_brk = r_debug_state;
461 	r_debug.r_state = RT_CONSISTENT;
462 #endif
463 
464 	(void)link_elf_link_common_finish(linker_kernel_file);
465 	linker_kernel_file->flags |= LINKER_FILE_LINKED;
466 	TAILQ_INIT(&set_pcpu_list);
467 #ifdef VIMAGE
468 	TAILQ_INIT(&set_vnet_list);
469 #endif
470 }
471 
472 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
473 
474 static int
475 link_elf_preload_parse_symbols(elf_file_t ef)
476 {
477 	caddr_t pointer;
478 	caddr_t ssym, esym, base;
479 	caddr_t strtab;
480 	int strcnt;
481 	Elf_Sym *symtab;
482 	int symcnt;
483 
484 	if (ef->modptr == NULL)
485 		return (0);
486 	pointer = preload_search_info(ef->modptr,
487 	    MODINFO_METADATA | MODINFOMD_SSYM);
488 	if (pointer == NULL)
489 		return (0);
490 	ssym = *(caddr_t *)pointer;
491 	pointer = preload_search_info(ef->modptr,
492 	    MODINFO_METADATA | MODINFOMD_ESYM);
493 	if (pointer == NULL)
494 		return (0);
495 	esym = *(caddr_t *)pointer;
496 
497 	base = ssym;
498 
499 	symcnt = *(long *)base;
500 	base += sizeof(long);
501 	symtab = (Elf_Sym *)base;
502 	base += roundup(symcnt, sizeof(long));
503 
504 	if (base > esym || base < ssym) {
505 		printf("Symbols are corrupt!\n");
506 		return (EINVAL);
507 	}
508 
509 	strcnt = *(long *)base;
510 	base += sizeof(long);
511 	strtab = base;
512 	base += roundup(strcnt, sizeof(long));
513 
514 	if (base > esym || base < ssym) {
515 		printf("Symbols are corrupt!\n");
516 		return (EINVAL);
517 	}
518 
519 	ef->ddbsymtab = symtab;
520 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
521 	ef->ddbstrtab = strtab;
522 	ef->ddbstrcnt = strcnt;
523 
524 	return (0);
525 }
526 
527 static int
528 parse_dynamic(elf_file_t ef)
529 {
530 	Elf_Dyn *dp;
531 	int plttype = DT_REL;
532 
533 	for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
534 		switch (dp->d_tag) {
535 		case DT_HASH:
536 		{
537 			/* From src/libexec/rtld-elf/rtld.c */
538 			const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
539 			    (ef->address + dp->d_un.d_ptr);
540 			ef->nbuckets = hashtab[0];
541 			ef->nchains = hashtab[1];
542 			ef->buckets = hashtab + 2;
543 			ef->chains = ef->buckets + ef->nbuckets;
544 			break;
545 		}
546 		case DT_STRTAB:
547 			ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
548 			break;
549 		case DT_STRSZ:
550 			ef->strsz = dp->d_un.d_val;
551 			break;
552 		case DT_SYMTAB:
553 			ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
554 			break;
555 		case DT_SYMENT:
556 			if (dp->d_un.d_val != sizeof(Elf_Sym))
557 				return (ENOEXEC);
558 			break;
559 		case DT_PLTGOT:
560 			ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
561 			break;
562 		case DT_REL:
563 			ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
564 			break;
565 		case DT_RELSZ:
566 			ef->relsize = dp->d_un.d_val;
567 			break;
568 		case DT_RELENT:
569 			if (dp->d_un.d_val != sizeof(Elf_Rel))
570 				return (ENOEXEC);
571 			break;
572 		case DT_JMPREL:
573 			ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
574 			break;
575 		case DT_PLTRELSZ:
576 			ef->pltrelsize = dp->d_un.d_val;
577 			break;
578 		case DT_RELA:
579 			ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
580 			break;
581 		case DT_RELASZ:
582 			ef->relasize = dp->d_un.d_val;
583 			break;
584 		case DT_RELAENT:
585 			if (dp->d_un.d_val != sizeof(Elf_Rela))
586 				return (ENOEXEC);
587 			break;
588 		case DT_PLTREL:
589 			plttype = dp->d_un.d_val;
590 			if (plttype != DT_REL && plttype != DT_RELA)
591 				return (ENOEXEC);
592 			break;
593 #ifdef GDB
594 		case DT_DEBUG:
595 			dp->d_un.d_ptr = (Elf_Addr)&r_debug;
596 			break;
597 #endif
598 		}
599 	}
600 
601 	if (plttype == DT_RELA) {
602 		ef->pltrela = (const Elf_Rela *)ef->pltrel;
603 		ef->pltrel = NULL;
604 		ef->pltrelasize = ef->pltrelsize;
605 		ef->pltrelsize = 0;
606 	}
607 
608 	ef->ddbsymtab = ef->symtab;
609 	ef->ddbsymcnt = ef->nchains;
610 	ef->ddbstrtab = ef->strtab;
611 	ef->ddbstrcnt = ef->strsz;
612 
613 	return (0);
614 }
615 
616 static int
617 parse_dpcpu(elf_file_t ef)
618 {
619 	int count;
620 	int error;
621 
622 	ef->pcpu_start = 0;
623 	ef->pcpu_stop = 0;
624 	error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
625 	    (void ***)&ef->pcpu_stop, &count);
626 	/* Error just means there is no pcpu set to relocate. */
627 	if (error != 0)
628 		return (0);
629 	count *= sizeof(void *);
630 	/*
631 	 * Allocate space in the primary pcpu area.  Copy in our
632 	 * initialization from the data section and then initialize
633 	 * all per-cpu storage from that.
634 	 */
635 	ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
636 	if (ef->pcpu_base == 0)
637 		return (ENOSPC);
638 	memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
639 	dpcpu_copy((void *)ef->pcpu_base, count);
640 	elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
641 	    ef->pcpu_base);
642 
643 	return (0);
644 }
645 
646 #ifdef VIMAGE
647 static int
648 parse_vnet(elf_file_t ef)
649 {
650 	int count;
651 	int error;
652 
653 	ef->vnet_start = 0;
654 	ef->vnet_stop = 0;
655 	error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
656 	    (void ***)&ef->vnet_stop, &count);
657 	/* Error just means there is no vnet data set to relocate. */
658 	if (error != 0)
659 		return (0);
660 	count *= sizeof(void *);
661 	/*
662 	 * Allocate space in the primary vnet area.  Copy in our
663 	 * initialization from the data section and then initialize
664 	 * all per-vnet storage from that.
665 	 */
666 	ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
667 	if (ef->vnet_base == 0)
668 		return (ENOSPC);
669 	memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
670 	vnet_data_copy((void *)ef->vnet_base, count);
671 	elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
672 	    ef->vnet_base);
673 
674 	return (0);
675 }
676 #endif
677 
678 static int
679 link_elf_link_preload(linker_class_t cls,
680     const char* filename, linker_file_t *result)
681 {
682 	Elf_Addr *ctors_addrp;
683 	Elf_Size *ctors_sizep;
684 	caddr_t modptr, baseptr, sizeptr, dynptr;
685 	char *type;
686 	elf_file_t ef;
687 	linker_file_t lf;
688 	int error;
689 	vm_offset_t dp;
690 
691 	/* Look to see if we have the file preloaded */
692 	modptr = preload_search_by_name(filename);
693 	if (modptr == NULL)
694 		return (ENOENT);
695 
696 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
697 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
698 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
699 	dynptr = preload_search_info(modptr,
700 	    MODINFO_METADATA | MODINFOMD_DYNAMIC);
701 	if (type == NULL ||
702 	    (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
703 	     strcmp(type, "elf module") != 0))
704 		return (EFTYPE);
705 	if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
706 		return (EINVAL);
707 
708 	lf = linker_make_file(filename, &link_elf_class);
709 	if (lf == NULL)
710 		return (ENOMEM);
711 
712 	ef = (elf_file_t) lf;
713 	ef->preloaded = 1;
714 	ef->modptr = modptr;
715 	ef->address = *(caddr_t *)baseptr;
716 #ifdef SPARSE_MAPPING
717 	ef->object = 0;
718 #endif
719 	dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
720 	ef->dynamic = (Elf_Dyn *)dp;
721 	lf->address = ef->address;
722 	lf->size = *(size_t *)sizeptr;
723 
724 	ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
725 	    MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
726 	ctors_sizep = (Elf_Size *)preload_search_info(modptr,
727 	    MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
728 	if (ctors_addrp != NULL && ctors_sizep != NULL) {
729 		lf->ctors_addr = ef->address + *ctors_addrp;
730 		lf->ctors_size = *ctors_sizep;
731 	}
732 
733 	error = parse_dynamic(ef);
734 	if (error == 0)
735 		error = parse_dpcpu(ef);
736 #ifdef VIMAGE
737 	if (error == 0)
738 		error = parse_vnet(ef);
739 #endif
740 	if (error != 0) {
741 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
742 		return (error);
743 	}
744 	link_elf_reloc_local(lf);
745 	*result = lf;
746 	return (0);
747 }
748 
749 static int
750 link_elf_link_preload_finish(linker_file_t lf)
751 {
752 	elf_file_t ef;
753 	int error;
754 
755 	ef = (elf_file_t) lf;
756 	error = relocate_file(ef);
757 	if (error != 0)
758 		return (error);
759 	(void)link_elf_preload_parse_symbols(ef);
760 
761 	return (link_elf_link_common_finish(lf));
762 }
763 
764 static int
765 link_elf_load_file(linker_class_t cls, const char* filename,
766     linker_file_t* result)
767 {
768 	struct nameidata nd;
769 	struct thread* td = curthread;	/* XXX */
770 	Elf_Ehdr *hdr;
771 	caddr_t firstpage;
772 	int nbytes, i;
773 	Elf_Phdr *phdr;
774 	Elf_Phdr *phlimit;
775 	Elf_Phdr *segs[MAXSEGS];
776 	int nsegs;
777 	Elf_Phdr *phdyn;
778 	caddr_t mapbase;
779 	size_t mapsize;
780 	Elf_Addr base_vaddr;
781 	Elf_Addr base_vlimit;
782 	int error = 0;
783 	ssize_t resid;
784 	int flags;
785 	elf_file_t ef;
786 	linker_file_t lf;
787 	Elf_Shdr *shdr;
788 	int symtabindex;
789 	int symstrindex;
790 	int shstrindex;
791 	int symcnt;
792 	int strcnt;
793 	char *shstrs;
794 
795 	shdr = NULL;
796 	lf = NULL;
797 	shstrs = NULL;
798 
799 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
800 	flags = FREAD;
801 	error = vn_open(&nd, &flags, 0, NULL);
802 	if (error != 0)
803 		return (error);
804 	NDFREE(&nd, NDF_ONLY_PNBUF);
805 	if (nd.ni_vp->v_type != VREG) {
806 		error = ENOEXEC;
807 		firstpage = NULL;
808 		goto out;
809 	}
810 #ifdef MAC
811 	error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
812 	if (error != 0) {
813 		firstpage = NULL;
814 		goto out;
815 	}
816 #endif
817 
818 	/*
819 	 * Read the elf header from the file.
820 	 */
821 	firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
822 	hdr = (Elf_Ehdr *)firstpage;
823 	error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
824 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
825 	    &resid, td);
826 	nbytes = PAGE_SIZE - resid;
827 	if (error != 0)
828 		goto out;
829 
830 	if (!IS_ELF(*hdr)) {
831 		error = ENOEXEC;
832 		goto out;
833 	}
834 
835 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
836 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
837 		link_elf_error(filename, "Unsupported file layout");
838 		error = ENOEXEC;
839 		goto out;
840 	}
841 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
842 	    hdr->e_version != EV_CURRENT) {
843 		link_elf_error(filename, "Unsupported file version");
844 		error = ENOEXEC;
845 		goto out;
846 	}
847 	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
848 		error = ENOSYS;
849 		goto out;
850 	}
851 	if (hdr->e_machine != ELF_TARG_MACH) {
852 		link_elf_error(filename, "Unsupported machine");
853 		error = ENOEXEC;
854 		goto out;
855 	}
856 
857 	/*
858 	 * We rely on the program header being in the first page.
859 	 * This is not strictly required by the ABI specification, but
860 	 * it seems to always true in practice.  And, it simplifies
861 	 * things considerably.
862 	 */
863 	if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
864 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
865 	      (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
866 		link_elf_error(filename, "Unreadable program headers");
867 
868 	/*
869 	 * Scan the program header entries, and save key information.
870 	 *
871 	 * We rely on there being exactly two load segments, text and data,
872 	 * in that order.
873 	 */
874 	phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
875 	phlimit = phdr + hdr->e_phnum;
876 	nsegs = 0;
877 	phdyn = NULL;
878 	while (phdr < phlimit) {
879 		switch (phdr->p_type) {
880 		case PT_LOAD:
881 			if (nsegs == MAXSEGS) {
882 				link_elf_error(filename, "Too many sections");
883 				error = ENOEXEC;
884 				goto out;
885 			}
886 			/*
887 			 * XXX: We just trust they come in right order ??
888 			 */
889 			segs[nsegs] = phdr;
890 			++nsegs;
891 			break;
892 
893 		case PT_DYNAMIC:
894 			phdyn = phdr;
895 			break;
896 
897 		case PT_INTERP:
898 			error = ENOSYS;
899 			goto out;
900 		}
901 
902 		++phdr;
903 	}
904 	if (phdyn == NULL) {
905 		link_elf_error(filename, "Object is not dynamically-linked");
906 		error = ENOEXEC;
907 		goto out;
908 	}
909 	if (nsegs == 0) {
910 		link_elf_error(filename, "No sections");
911 		error = ENOEXEC;
912 		goto out;
913 	}
914 
915 	/*
916 	 * Allocate the entire address space of the object, to stake
917 	 * out our contiguous region, and to establish the base
918 	 * address for relocation.
919 	 */
920 	base_vaddr = trunc_page(segs[0]->p_vaddr);
921 	base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
922 	    segs[nsegs - 1]->p_memsz);
923 	mapsize = base_vlimit - base_vaddr;
924 
925 	lf = linker_make_file(filename, &link_elf_class);
926 	if (lf == NULL) {
927 		error = ENOMEM;
928 		goto out;
929 	}
930 
931 	ef = (elf_file_t) lf;
932 #ifdef SPARSE_MAPPING
933 	ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
934 	if (ef->object == NULL) {
935 		error = ENOMEM;
936 		goto out;
937 	}
938 	ef->address = (caddr_t) vm_map_min(kernel_map);
939 	error = vm_map_find(kernel_map, ef->object, 0,
940 	    (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE,
941 	    VM_PROT_ALL, VM_PROT_ALL, 0);
942 	if (error != 0) {
943 		vm_object_deallocate(ef->object);
944 		ef->object = 0;
945 		goto out;
946 	}
947 #else
948 	ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
949 #endif
950 	mapbase = ef->address;
951 
952 	/*
953 	 * Read the text and data sections and zero the bss.
954 	 */
955 	for (i = 0; i < nsegs; i++) {
956 		caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
957 		error = vn_rdwr(UIO_READ, nd.ni_vp,
958 		    segbase, segs[i]->p_filesz, segs[i]->p_offset,
959 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
960 		    &resid, td);
961 		if (error != 0)
962 			goto out;
963 		bzero(segbase + segs[i]->p_filesz,
964 		    segs[i]->p_memsz - segs[i]->p_filesz);
965 
966 #ifdef SPARSE_MAPPING
967 		/*
968 		 * Wire down the pages
969 		 */
970 		error = vm_map_wire(kernel_map,
971 		    (vm_offset_t) segbase,
972 		    (vm_offset_t) segbase + segs[i]->p_memsz,
973 		    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
974 		if (error != KERN_SUCCESS) {
975 			error = ENOMEM;
976 			goto out;
977 		}
978 #endif
979 	}
980 
981 #ifdef GPROF
982 	/* Update profiling information with the new text segment. */
983 	mtx_lock(&Giant);
984 	kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
985 	    segs[0]->p_memsz));
986 	mtx_unlock(&Giant);
987 #endif
988 
989 	ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
990 
991 	lf->address = ef->address;
992 	lf->size = mapsize;
993 
994 	error = parse_dynamic(ef);
995 	if (error != 0)
996 		goto out;
997 	error = parse_dpcpu(ef);
998 	if (error != 0)
999 		goto out;
1000 #ifdef VIMAGE
1001 	error = parse_vnet(ef);
1002 	if (error != 0)
1003 		goto out;
1004 #endif
1005 	link_elf_reloc_local(lf);
1006 
1007 	VOP_UNLOCK(nd.ni_vp, 0);
1008 	error = linker_load_dependencies(lf);
1009 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1010 	if (error != 0)
1011 		goto out;
1012 	error = relocate_file(ef);
1013 	if (error != 0)
1014 		goto out;
1015 
1016 	/*
1017 	 * Try and load the symbol table if it's present.  (you can
1018 	 * strip it!)
1019 	 */
1020 	nbytes = hdr->e_shnum * hdr->e_shentsize;
1021 	if (nbytes == 0 || hdr->e_shoff == 0)
1022 		goto nosyms;
1023 	shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1024 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1025 	    (caddr_t)shdr, nbytes, hdr->e_shoff,
1026 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1027 	    &resid, td);
1028 	if (error != 0)
1029 		goto out;
1030 
1031 	/* Read section string table */
1032 	shstrindex = hdr->e_shstrndx;
1033 	if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1034 	    shdr[shstrindex].sh_size != 0) {
1035 		nbytes = shdr[shstrindex].sh_size;
1036 		shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1037 		error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1038 		    shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1039 		    td->td_ucred, NOCRED, &resid, td);
1040 		if (error)
1041 			goto out;
1042 	}
1043 
1044 	symtabindex = -1;
1045 	symstrindex = -1;
1046 	for (i = 0; i < hdr->e_shnum; i++) {
1047 		if (shdr[i].sh_type == SHT_SYMTAB) {
1048 			symtabindex = i;
1049 			symstrindex = shdr[i].sh_link;
1050 		} else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1051 		    strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1052 			/* Record relocated address and size of .ctors. */
1053 			lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1054 			lf->ctors_size = shdr[i].sh_size;
1055 		}
1056 	}
1057 	if (symtabindex < 0 || symstrindex < 0)
1058 		goto nosyms;
1059 
1060 	symcnt = shdr[symtabindex].sh_size;
1061 	ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1062 	strcnt = shdr[symstrindex].sh_size;
1063 	ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1064 
1065 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1066 	    ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1067 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1068 	    &resid, td);
1069 	if (error != 0)
1070 		goto out;
1071 	error = vn_rdwr(UIO_READ, nd.ni_vp,
1072 	    ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1073 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1074 	    &resid, td);
1075 	if (error != 0)
1076 		goto out;
1077 
1078 	ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1079 	ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1080 	ef->ddbstrcnt = strcnt;
1081 	ef->ddbstrtab = ef->strbase;
1082 
1083 nosyms:
1084 	error = link_elf_link_common_finish(lf);
1085 	if (error != 0)
1086 		goto out;
1087 
1088 	*result = lf;
1089 
1090 out:
1091 	VOP_UNLOCK(nd.ni_vp, 0);
1092 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1093 	if (error != 0 && lf != NULL)
1094 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1095 	free(shdr, M_LINKER);
1096 	free(firstpage, M_LINKER);
1097 	free(shstrs, M_LINKER);
1098 
1099 	return (error);
1100 }
1101 
1102 Elf_Addr
1103 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1104 {
1105 	elf_file_t ef;
1106 
1107 	ef = (elf_file_t)lf;
1108 	if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1109 		return ((x - ef->pcpu_start) + ef->pcpu_base);
1110 #ifdef VIMAGE
1111 	if (x >= ef->vnet_start && x < ef->vnet_stop)
1112 		return ((x - ef->vnet_start) + ef->vnet_base);
1113 #endif
1114 	return (x);
1115 }
1116 
1117 
1118 static void
1119 link_elf_unload_file(linker_file_t file)
1120 {
1121 	elf_file_t ef = (elf_file_t) file;
1122 
1123 	if (ef->pcpu_base != 0) {
1124 		dpcpu_free((void *)ef->pcpu_base,
1125 		    ef->pcpu_stop - ef->pcpu_start);
1126 		elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1127 	}
1128 #ifdef VIMAGE
1129 	if (ef->vnet_base != 0) {
1130 		vnet_data_free((void *)ef->vnet_base,
1131 		    ef->vnet_stop - ef->vnet_start);
1132 		elf_set_delete(&set_vnet_list, ef->vnet_start);
1133 	}
1134 #endif
1135 #ifdef GDB
1136 	if (ef->gdb.l_ld != NULL) {
1137 		GDB_STATE(RT_DELETE);
1138 		free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1139 		link_elf_delete_gdb(&ef->gdb);
1140 		GDB_STATE(RT_CONSISTENT);
1141 	}
1142 #endif
1143 
1144 	/* Notify MD code that a module is being unloaded. */
1145 	elf_cpu_unload_file(file);
1146 
1147 	if (ef->preloaded) {
1148 		link_elf_unload_preload(file);
1149 		return;
1150 	}
1151 
1152 #ifdef SPARSE_MAPPING
1153 	if (ef->object != NULL) {
1154 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1155 		    (vm_offset_t) ef->address
1156 		    + (ef->object->size << PAGE_SHIFT));
1157 	}
1158 #else
1159 	free(ef->address, M_LINKER);
1160 #endif
1161 	free(ef->symbase, M_LINKER);
1162 	free(ef->strbase, M_LINKER);
1163 	free(ef->ctftab, M_LINKER);
1164 	free(ef->ctfoff, M_LINKER);
1165 	free(ef->typoff, M_LINKER);
1166 }
1167 
1168 static void
1169 link_elf_unload_preload(linker_file_t file)
1170 {
1171 	if (file->filename != NULL)
1172 		preload_delete_name(file->filename);
1173 }
1174 
1175 static const char *
1176 symbol_name(elf_file_t ef, Elf_Size r_info)
1177 {
1178 	const Elf_Sym *ref;
1179 
1180 	if (ELF_R_SYM(r_info)) {
1181 		ref = ef->symtab + ELF_R_SYM(r_info);
1182 		return (ef->strtab + ref->st_name);
1183 	}
1184 	return (NULL);
1185 }
1186 
1187 static int
1188 relocate_file1(elf_file_t ef, int (*elf_reloc_func)(linker_file_t lf,
1189     Elf_Addr relocbase, const void *data, int type, elf_lookup_fn lookup))
1190 {
1191 	const Elf_Rel *rellim;
1192 	const Elf_Rel *rel;
1193 	const Elf_Rela *relalim;
1194 	const Elf_Rela *rela;
1195 	const char *symname;
1196 
1197 	/* Perform relocations without addend if there are any: */
1198 	rel = ef->rel;
1199 	if (rel != NULL) {
1200 		rellim = (const Elf_Rel *)
1201 		    ((const char *)ef->rel + ef->relsize);
1202 		while (rel < rellim) {
1203 			if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rel,
1204 			    ELF_RELOC_REL, elf_lookup)) {
1205 				symname = symbol_name(ef, rel->r_info);
1206 				printf("link_elf: symbol %s undefined\n", symname);
1207 				return (ENOENT);
1208 			}
1209 			rel++;
1210 		}
1211 	}
1212 
1213 	/* Perform relocations with addend if there are any: */
1214 	rela = ef->rela;
1215 	if (rela != NULL) {
1216 		relalim = (const Elf_Rela *)
1217 		    ((const char *)ef->rela + ef->relasize);
1218 		while (rela < relalim) {
1219 			if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rela,
1220 			    ELF_RELOC_RELA, elf_lookup)) {
1221 				symname = symbol_name(ef, rela->r_info);
1222 				printf("link_elf: symbol %s undefined\n",
1223 				    symname);
1224 				return (ENOENT);
1225 			}
1226 			rela++;
1227 		}
1228 	}
1229 
1230 	/* Perform PLT relocations without addend if there are any: */
1231 	rel = ef->pltrel;
1232 	if (rel != NULL) {
1233 		rellim = (const Elf_Rel *)
1234 		    ((const char *)ef->pltrel + ef->pltrelsize);
1235 		while (rel < rellim) {
1236 			if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rel,
1237 			    ELF_RELOC_REL, elf_lookup)) {
1238 				symname = symbol_name(ef, rel->r_info);
1239 				printf("link_elf: symbol %s undefined\n",
1240 				    symname);
1241 				return (ENOENT);
1242 			}
1243 			rel++;
1244 		}
1245 	}
1246 
1247 	/* Perform relocations with addend if there are any: */
1248 	rela = ef->pltrela;
1249 	if (rela != NULL) {
1250 		relalim = (const Elf_Rela *)
1251 		    ((const char *)ef->pltrela + ef->pltrelasize);
1252 		while (rela < relalim) {
1253 			if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rela,
1254 			    ELF_RELOC_RELA, elf_lookup)) {
1255 				symname = symbol_name(ef, rela->r_info);
1256 				printf("link_elf: symbol %s undefined\n",
1257 				    symname);
1258 				return (ENOENT);
1259 			}
1260 			rela++;
1261 		}
1262 	}
1263 
1264 	return (0);
1265 }
1266 
1267 static int
1268 relocate_file(elf_file_t ef)
1269 {
1270 	int e;
1271 
1272 	e = relocate_file1(ef, elf_reloc);
1273 #if defined(__i386__) || defined(__amd64__)
1274 	if (e == 0)
1275 		e = relocate_file1(ef, elf_reloc_ifunc);
1276 #endif
1277 	return (e);
1278 }
1279 
1280 /*
1281  * Hash function for symbol table lookup.  Don't even think about changing
1282  * this.  It is specified by the System V ABI.
1283  */
1284 static unsigned long
1285 elf_hash(const char *name)
1286 {
1287 	const unsigned char *p = (const unsigned char *) name;
1288 	unsigned long h = 0;
1289 	unsigned long g;
1290 
1291 	while (*p != '\0') {
1292 		h = (h << 4) + *p++;
1293 		if ((g = h & 0xf0000000) != 0)
1294 			h ^= g >> 24;
1295 		h &= ~g;
1296 	}
1297 	return (h);
1298 }
1299 
1300 static int
1301 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1302 {
1303 	elf_file_t ef = (elf_file_t) lf;
1304 	unsigned long symnum;
1305 	const Elf_Sym* symp;
1306 	const char *strp;
1307 	unsigned long hash;
1308 	int i;
1309 
1310 	/* If we don't have a hash, bail. */
1311 	if (ef->buckets == NULL || ef->nbuckets == 0) {
1312 		printf("link_elf_lookup_symbol: missing symbol hash table\n");
1313 		return (ENOENT);
1314 	}
1315 
1316 	/* First, search hashed global symbols */
1317 	hash = elf_hash(name);
1318 	symnum = ef->buckets[hash % ef->nbuckets];
1319 
1320 	while (symnum != STN_UNDEF) {
1321 		if (symnum >= ef->nchains) {
1322 			printf("%s: corrupt symbol table\n", __func__);
1323 			return (ENOENT);
1324 		}
1325 
1326 		symp = ef->symtab + symnum;
1327 		if (symp->st_name == 0) {
1328 			printf("%s: corrupt symbol table\n", __func__);
1329 			return (ENOENT);
1330 		}
1331 
1332 		strp = ef->strtab + symp->st_name;
1333 
1334 		if (strcmp(name, strp) == 0) {
1335 			if (symp->st_shndx != SHN_UNDEF ||
1336 			    (symp->st_value != 0 &&
1337 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1338 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1339 				*sym = (c_linker_sym_t) symp;
1340 				return (0);
1341 			}
1342 			return (ENOENT);
1343 		}
1344 
1345 		symnum = ef->chains[symnum];
1346 	}
1347 
1348 	/* If we have not found it, look at the full table (if loaded) */
1349 	if (ef->symtab == ef->ddbsymtab)
1350 		return (ENOENT);
1351 
1352 	/* Exhaustive search */
1353 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1354 		strp = ef->ddbstrtab + symp->st_name;
1355 		if (strcmp(name, strp) == 0) {
1356 			if (symp->st_shndx != SHN_UNDEF ||
1357 			    (symp->st_value != 0 &&
1358 			    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1359 			    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1360 				*sym = (c_linker_sym_t) symp;
1361 				return (0);
1362 			}
1363 			return (ENOENT);
1364 		}
1365 	}
1366 
1367 	return (ENOENT);
1368 }
1369 
1370 static int
1371 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1372     linker_symval_t *symval)
1373 {
1374 	elf_file_t ef;
1375 	const Elf_Sym *es;
1376 	caddr_t val;
1377 
1378 	ef = (elf_file_t)lf;
1379 	es = (const Elf_Sym *)sym;
1380 	if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1381 		symval->name = ef->strtab + es->st_name;
1382 		val = (caddr_t)ef->address + es->st_value;
1383 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1384 			val = ((caddr_t (*)(void))val)();
1385 		symval->value = val;
1386 		symval->size = es->st_size;
1387 		return (0);
1388 	}
1389 	if (ef->symtab == ef->ddbsymtab)
1390 		return (ENOENT);
1391 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1392 		symval->name = ef->ddbstrtab + es->st_name;
1393 		val = (caddr_t)ef->address + es->st_value;
1394 		if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1395 			val = ((caddr_t (*)(void))val)();
1396 		symval->value = val;
1397 		symval->size = es->st_size;
1398 		return (0);
1399 	}
1400 	return (ENOENT);
1401 }
1402 
1403 static int
1404 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1405     c_linker_sym_t *sym, long *diffp)
1406 {
1407 	elf_file_t ef = (elf_file_t) lf;
1408 	u_long off = (uintptr_t) (void *) value;
1409 	u_long diff = off;
1410 	u_long st_value;
1411 	const Elf_Sym* es;
1412 	const Elf_Sym* best = NULL;
1413 	int i;
1414 
1415 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1416 		if (es->st_name == 0)
1417 			continue;
1418 		st_value = es->st_value + (uintptr_t) (void *) ef->address;
1419 		if (off >= st_value) {
1420 			if (off - st_value < diff) {
1421 				diff = off - st_value;
1422 				best = es;
1423 				if (diff == 0)
1424 					break;
1425 			} else if (off - st_value == diff) {
1426 				best = es;
1427 			}
1428 		}
1429 	}
1430 	if (best == NULL)
1431 		*diffp = off;
1432 	else
1433 		*diffp = diff;
1434 	*sym = (c_linker_sym_t) best;
1435 
1436 	return (0);
1437 }
1438 
1439 /*
1440  * Look up a linker set on an ELF system.
1441  */
1442 static int
1443 link_elf_lookup_set(linker_file_t lf, const char *name,
1444     void ***startp, void ***stopp, int *countp)
1445 {
1446 	c_linker_sym_t sym;
1447 	linker_symval_t symval;
1448 	char *setsym;
1449 	void **start, **stop;
1450 	int len, error = 0, count;
1451 
1452 	len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1453 	setsym = malloc(len, M_LINKER, M_WAITOK);
1454 
1455 	/* get address of first entry */
1456 	snprintf(setsym, len, "%s%s", "__start_set_", name);
1457 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1458 	if (error != 0)
1459 		goto out;
1460 	link_elf_symbol_values(lf, sym, &symval);
1461 	if (symval.value == 0) {
1462 		error = ESRCH;
1463 		goto out;
1464 	}
1465 	start = (void **)symval.value;
1466 
1467 	/* get address of last entry */
1468 	snprintf(setsym, len, "%s%s", "__stop_set_", name);
1469 	error = link_elf_lookup_symbol(lf, setsym, &sym);
1470 	if (error != 0)
1471 		goto out;
1472 	link_elf_symbol_values(lf, sym, &symval);
1473 	if (symval.value == 0) {
1474 		error = ESRCH;
1475 		goto out;
1476 	}
1477 	stop = (void **)symval.value;
1478 
1479 	/* and the number of entries */
1480 	count = stop - start;
1481 
1482 	/* and copy out */
1483 	if (startp != NULL)
1484 		*startp = start;
1485 	if (stopp != NULL)
1486 		*stopp = stop;
1487 	if (countp != NULL)
1488 		*countp = count;
1489 
1490 out:
1491 	free(setsym, M_LINKER);
1492 	return (error);
1493 }
1494 
1495 static int
1496 link_elf_each_function_name(linker_file_t file,
1497   int (*callback)(const char *, void *), void *opaque)
1498 {
1499 	elf_file_t ef = (elf_file_t)file;
1500 	const Elf_Sym *symp;
1501 	int i, error;
1502 
1503 	/* Exhaustive search */
1504 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1505 		if (symp->st_value != 0 &&
1506 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1507 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1508 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1509 			if (error != 0)
1510 				return (error);
1511 		}
1512 	}
1513 	return (0);
1514 }
1515 
1516 static int
1517 link_elf_each_function_nameval(linker_file_t file,
1518     linker_function_nameval_callback_t callback, void *opaque)
1519 {
1520 	linker_symval_t symval;
1521 	elf_file_t ef = (elf_file_t)file;
1522 	const Elf_Sym* symp;
1523 	int i, error;
1524 
1525 	/* Exhaustive search */
1526 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1527 		if (symp->st_value != 0 &&
1528 		    (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1529 		    ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1530 			error = link_elf_symbol_values(file,
1531 			    (c_linker_sym_t) symp, &symval);
1532 			if (error != 0)
1533 				return (error);
1534 			error = callback(file, i, &symval, opaque);
1535 			if (error != 0)
1536 				return (error);
1537 		}
1538 	}
1539 	return (0);
1540 }
1541 
1542 const Elf_Sym *
1543 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1544 {
1545 	elf_file_t ef = (elf_file_t)lf;
1546 
1547 	if (symidx >= ef->nchains)
1548 		return (NULL);
1549 	return (ef->symtab + symidx);
1550 }
1551 
1552 const char *
1553 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1554 {
1555 	elf_file_t ef = (elf_file_t)lf;
1556 	const Elf_Sym *sym;
1557 
1558 	if (symidx >= ef->nchains)
1559 		return (NULL);
1560 	sym = ef->symtab + symidx;
1561 	return (ef->strtab + sym->st_name);
1562 }
1563 
1564 /*
1565  * Symbol lookup function that can be used when the symbol index is known (ie
1566  * in relocations). It uses the symbol index instead of doing a fully fledged
1567  * hash table based lookup when such is valid. For example for local symbols.
1568  * This is not only more efficient, it's also more correct. It's not always
1569  * the case that the symbol can be found through the hash table.
1570  */
1571 static int
1572 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1573 {
1574 	elf_file_t ef = (elf_file_t)lf;
1575 	const Elf_Sym *sym;
1576 	const char *symbol;
1577 	Elf_Addr addr, start, base;
1578 
1579 	/* Don't even try to lookup the symbol if the index is bogus. */
1580 	if (symidx >= ef->nchains) {
1581 		*res = 0;
1582 		return (EINVAL);
1583 	}
1584 
1585 	sym = ef->symtab + symidx;
1586 
1587 	/*
1588 	 * Don't do a full lookup when the symbol is local. It may even
1589 	 * fail because it may not be found through the hash table.
1590 	 */
1591 	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1592 		/* Force lookup failure when we have an insanity. */
1593 		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1594 			*res = 0;
1595 			return (EINVAL);
1596 		}
1597 		*res = ((Elf_Addr)ef->address + sym->st_value);
1598 		return (0);
1599 	}
1600 
1601 	/*
1602 	 * XXX we can avoid doing a hash table based lookup for global
1603 	 * symbols as well. This however is not always valid, so we'll
1604 	 * just do it the hard way for now. Performance tweaks can
1605 	 * always be added.
1606 	 */
1607 
1608 	symbol = ef->strtab + sym->st_name;
1609 
1610 	/* Force a lookup failure if the symbol name is bogus. */
1611 	if (*symbol == 0) {
1612 		*res = 0;
1613 		return (EINVAL);
1614 	}
1615 
1616 	addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1617 	if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1618 		*res = 0;
1619 		return (EINVAL);
1620 	}
1621 
1622 	if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1623 		addr = addr - start + base;
1624 #ifdef VIMAGE
1625 	else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1626 		addr = addr - start + base;
1627 #endif
1628 	*res = addr;
1629 	return (0);
1630 }
1631 
1632 static void
1633 link_elf_reloc_local(linker_file_t lf)
1634 {
1635 	const Elf_Rel *rellim;
1636 	const Elf_Rel *rel;
1637 	const Elf_Rela *relalim;
1638 	const Elf_Rela *rela;
1639 	elf_file_t ef = (elf_file_t)lf;
1640 
1641 	/* Perform relocations without addend if there are any: */
1642 	if ((rel = ef->rel) != NULL) {
1643 		rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1644 		while (rel < rellim) {
1645 			elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1646 			    ELF_RELOC_REL, elf_lookup);
1647 			rel++;
1648 		}
1649 	}
1650 
1651 	/* Perform relocations with addend if there are any: */
1652 	if ((rela = ef->rela) != NULL) {
1653 		relalim = (const Elf_Rela *)
1654 		    ((const char *)ef->rela + ef->relasize);
1655 		while (rela < relalim) {
1656 			elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1657 			    ELF_RELOC_RELA, elf_lookup);
1658 			rela++;
1659 		}
1660 	}
1661 }
1662 
1663 static long
1664 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1665 {
1666 	elf_file_t ef = (elf_file_t)lf;
1667 
1668 	*symtab = ef->ddbsymtab;
1669 
1670 	if (*symtab == NULL)
1671 		return (0);
1672 
1673 	return (ef->ddbsymcnt);
1674 }
1675 
1676 static long
1677 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1678 {
1679 	elf_file_t ef = (elf_file_t)lf;
1680 
1681 	*strtab = ef->ddbstrtab;
1682 
1683 	if (*strtab == NULL)
1684 		return (0);
1685 
1686 	return (ef->ddbstrcnt);
1687 }
1688 
1689 #if defined(__i386__) || defined(__amd64__)
1690 void
1691 link_elf_ireloc(caddr_t kmdp)
1692 {
1693 	struct elf_file eff;
1694 	elf_file_t ef;
1695 	volatile char *c;
1696 	size_t i;
1697 
1698 	ef =  &eff;
1699 
1700 	/* Do not use bzero/memset before ireloc is done. */
1701 	for (c = (char *)ef, i = 0; i < sizeof(*ef); i++)
1702 		c[i] = 0;
1703 
1704 	ef->modptr = kmdp;
1705 	ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1706 	parse_dynamic(ef);
1707 	ef->address = 0;
1708 	link_elf_preload_parse_symbols(ef);
1709 	relocate_file1(ef, elf_reloc_ifunc);
1710 }
1711 #endif
1712