xref: /freebsd/sys/kern/link_elf_obj.c (revision a3cf0ef5a295c885c895fabfd56470c0d1db322d)
1 /*-
2  * Copyright (c) 1998-2000 Doug Rabson
3  * Copyright (c) 2004 Peter Wemm
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include "opt_ddb.h"
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/mutex.h>
39 #include <sys/mount.h>
40 #include <sys/proc.h>
41 #include <sys/namei.h>
42 #include <sys/fcntl.h>
43 #include <sys/vnode.h>
44 #include <sys/linker.h>
45 
46 #include <machine/elf.h>
47 
48 #include <net/vnet.h>
49 
50 #include <security/mac/mac_framework.h>
51 
52 #include <vm/vm.h>
53 #include <vm/vm_param.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_kern.h>
56 #include <vm/vm_extern.h>
57 #include <vm/pmap.h>
58 #include <vm/vm_map.h>
59 
60 #include <sys/link_elf.h>
61 
62 #ifdef DDB_CTF
63 #include <net/zlib.h>
64 #endif
65 
66 #include "linker_if.h"
67 
68 typedef struct {
69 	void		*addr;
70 	Elf_Off		size;
71 	int		flags;
72 	int		sec;	/* Original section */
73 	char		*name;
74 } Elf_progent;
75 
76 typedef struct {
77 	Elf_Rel		*rel;
78 	int		nrel;
79 	int		sec;
80 } Elf_relent;
81 
82 typedef struct {
83 	Elf_Rela	*rela;
84 	int		nrela;
85 	int		sec;
86 } Elf_relaent;
87 
88 
89 typedef struct elf_file {
90 	struct linker_file lf;		/* Common fields */
91 
92 	int		preloaded;
93 	caddr_t		address;	/* Relocation address */
94 	vm_object_t	object;		/* VM object to hold file pages */
95 	Elf_Shdr	*e_shdr;
96 
97 	Elf_progent	*progtab;
98 	int		nprogtab;
99 
100 	Elf_relaent	*relatab;
101 	int		nrelatab;
102 
103 	Elf_relent	*reltab;
104 	int		nreltab;
105 
106 	Elf_Sym		*ddbsymtab;	/* The symbol table we are using */
107 	long		ddbsymcnt;	/* Number of symbols */
108 	caddr_t		ddbstrtab;	/* String table */
109 	long		ddbstrcnt;	/* number of bytes in string table */
110 
111 	caddr_t		shstrtab;	/* Section name string table */
112 	long		shstrcnt;	/* number of bytes in string table */
113 
114 	caddr_t		ctftab;		/* CTF table */
115 	long		ctfcnt;		/* number of bytes in CTF table */
116 	caddr_t		ctfoff;		/* CTF offset table */
117 	caddr_t		typoff;		/* Type offset table */
118 	long		typlen;		/* Number of type entries. */
119 
120 } *elf_file_t;
121 
122 #include <kern/kern_ctf.c>
123 
124 static int	link_elf_link_preload(linker_class_t cls,
125 		    const char *, linker_file_t *);
126 static int	link_elf_link_preload_finish(linker_file_t);
127 static int	link_elf_load_file(linker_class_t, const char *, linker_file_t *);
128 static int	link_elf_lookup_symbol(linker_file_t, const char *,
129 		    c_linker_sym_t *);
130 static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
131 		    linker_symval_t *);
132 static int	link_elf_search_symbol(linker_file_t, caddr_t value,
133 		    c_linker_sym_t *sym, long *diffp);
134 
135 static void	link_elf_unload_file(linker_file_t);
136 static int	link_elf_lookup_set(linker_file_t, const char *,
137 		    void ***, void ***, int *);
138 static int	link_elf_each_function_name(linker_file_t,
139 		    int (*)(const char *, void *), void *);
140 static int	link_elf_each_function_nameval(linker_file_t,
141 				linker_function_nameval_callback_t,
142 				void *);
143 static void	link_elf_reloc_local(linker_file_t);
144 static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
145 static long	link_elf_strtab_get(linker_file_t, caddr_t *);
146 
147 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps);
148 
149 static kobj_method_t link_elf_methods[] = {
150 	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
151 	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
152 	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
153 	KOBJMETHOD(linker_unload,		link_elf_unload_file),
154 	KOBJMETHOD(linker_load_file,		link_elf_load_file),
155 	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
156 	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
157 	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
158 	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
159 	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
160 	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
161 	KOBJMETHOD(linker_symtab_get, 		link_elf_symtab_get),
162 	KOBJMETHOD(linker_strtab_get, 		link_elf_strtab_get),
163 	{ 0, 0 }
164 };
165 
166 static struct linker_class link_elf_class = {
167 #if ELF_TARG_CLASS == ELFCLASS32
168 	"elf32_obj",
169 #else
170 	"elf64_obj",
171 #endif
172 	link_elf_methods, sizeof(struct elf_file)
173 };
174 
175 static int	relocate_file(elf_file_t ef);
176 
177 static void
178 link_elf_error(const char *filename, const char *s)
179 {
180 	if (filename == NULL)
181 		printf("kldload: %s\n", s);
182 	else
183 		printf("kldload: %s: %s\n", filename, s);
184 }
185 
186 static void
187 link_elf_init(void *arg)
188 {
189 
190 	linker_add_class(&link_elf_class);
191 }
192 
193 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
194 
195 static int
196 link_elf_link_preload(linker_class_t cls, const char *filename,
197     linker_file_t *result)
198 {
199 	Elf_Ehdr *hdr;
200 	Elf_Shdr *shdr;
201 	Elf_Sym *es;
202 	void *modptr, *baseptr, *sizeptr;
203 	char *type;
204 	elf_file_t ef;
205 	linker_file_t lf;
206 	Elf_Addr off;
207 	int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
208 
209 	/* Look to see if we have the file preloaded */
210 	modptr = preload_search_by_name(filename);
211 	if (modptr == NULL)
212 		return ENOENT;
213 
214 	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
215 	baseptr = preload_search_info(modptr, MODINFO_ADDR);
216 	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
217 	hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
218 	    MODINFOMD_ELFHDR);
219 	shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
220 	    MODINFOMD_SHDR);
221 	if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
222 	    " obj module") != 0 &&
223 	    strcmp(type, "elf obj module") != 0)) {
224 		return (EFTYPE);
225 	}
226 	if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
227 	    shdr == NULL)
228 		return (EINVAL);
229 
230 	lf = linker_make_file(filename, &link_elf_class);
231 	if (lf == NULL)
232 		return (ENOMEM);
233 
234 	ef = (elf_file_t)lf;
235 	ef->preloaded = 1;
236 	ef->address = *(caddr_t *)baseptr;
237 	lf->address = *(caddr_t *)baseptr;
238 	lf->size = *(size_t *)sizeptr;
239 
240 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
241 	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
242 	    hdr->e_ident[EI_VERSION] != EV_CURRENT ||
243 	    hdr->e_version != EV_CURRENT ||
244 	    hdr->e_type != ET_REL ||
245 	    hdr->e_machine != ELF_TARG_MACH) {
246 		error = EFTYPE;
247 		goto out;
248 	}
249 	ef->e_shdr = shdr;
250 
251 	/* Scan the section header for information and table sizing. */
252 	symtabindex = -1;
253 	symstrindex = -1;
254 	for (i = 0; i < hdr->e_shnum; i++) {
255 		switch (shdr[i].sh_type) {
256 		case SHT_PROGBITS:
257 		case SHT_NOBITS:
258 			ef->nprogtab++;
259 			break;
260 		case SHT_SYMTAB:
261 			symtabindex = i;
262 			symstrindex = shdr[i].sh_link;
263 			break;
264 		case SHT_REL:
265 			ef->nreltab++;
266 			break;
267 		case SHT_RELA:
268 			ef->nrelatab++;
269 			break;
270 		}
271 	}
272 
273 	shstrindex = hdr->e_shstrndx;
274 	if (ef->nprogtab == 0 || symstrindex < 0 ||
275 	    symstrindex >= hdr->e_shnum ||
276 	    shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
277 	    shstrindex >= hdr->e_shnum ||
278 	    shdr[shstrindex].sh_type != SHT_STRTAB) {
279 		printf("%s: bad/missing section headers\n", filename);
280 		error = ENOEXEC;
281 		goto out;
282 	}
283 
284 	/* Allocate space for tracking the load chunks */
285 	if (ef->nprogtab != 0)
286 		ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
287 		    M_LINKER, M_WAITOK | M_ZERO);
288 	if (ef->nreltab != 0)
289 		ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
290 		    M_LINKER, M_WAITOK | M_ZERO);
291 	if (ef->nrelatab != 0)
292 		ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
293 		    M_LINKER, M_WAITOK | M_ZERO);
294 	if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
295 	    (ef->nreltab != 0 && ef->reltab == NULL) ||
296 	    (ef->nrelatab != 0 && ef->relatab == NULL)) {
297 		error = ENOMEM;
298 		goto out;
299 	}
300 
301 	/* XXX, relocate the sh_addr fields saved by the loader. */
302 	off = 0;
303 	for (i = 0; i < hdr->e_shnum; i++) {
304 		if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
305 			off = shdr[i].sh_addr;
306 	}
307 	for (i = 0; i < hdr->e_shnum; i++) {
308 		if (shdr[i].sh_addr != 0)
309 			shdr[i].sh_addr = shdr[i].sh_addr - off +
310 			    (Elf_Addr)ef->address;
311 	}
312 
313 	ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
314 	ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
315 	ef->ddbstrcnt = shdr[symstrindex].sh_size;
316 	ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
317 	ef->shstrcnt = shdr[shstrindex].sh_size;
318 	ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
319 
320 	/* Now fill out progtab and the relocation tables. */
321 	pb = 0;
322 	rl = 0;
323 	ra = 0;
324 	for (i = 0; i < hdr->e_shnum; i++) {
325 		switch (shdr[i].sh_type) {
326 		case SHT_PROGBITS:
327 		case SHT_NOBITS:
328 			ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
329 			if (shdr[i].sh_type == SHT_PROGBITS)
330 				ef->progtab[pb].name = "<<PROGBITS>>";
331 			else
332 				ef->progtab[pb].name = "<<NOBITS>>";
333 			ef->progtab[pb].size = shdr[i].sh_size;
334 			ef->progtab[pb].sec = i;
335 			if (ef->shstrtab && shdr[i].sh_name != 0)
336 				ef->progtab[pb].name =
337 				    ef->shstrtab + shdr[i].sh_name;
338 			if (ef->progtab[pb].name != NULL &&
339 			    !strcmp(ef->progtab[pb].name, "set_pcpu")) {
340 				void *dpcpu;
341 
342 				dpcpu = dpcpu_alloc(shdr[i].sh_size);
343 				if (dpcpu == NULL) {
344 					error = ENOSPC;
345 					goto out;
346 				}
347 				memcpy(dpcpu, ef->progtab[pb].addr,
348 				    ef->progtab[pb].size);
349 				dpcpu_copy(dpcpu, shdr[i].sh_size);
350 				ef->progtab[pb].addr = dpcpu;
351 #ifdef VIMAGE
352 			} else if (ef->progtab[pb].name != NULL &&
353 			    !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
354 				void *vnet_data;
355 
356 				vnet_data = vnet_data_alloc(shdr[i].sh_size);
357 				if (vnet_data == NULL) {
358 					error = ENOSPC;
359 					goto out;
360 				}
361 				memcpy(vnet_data, ef->progtab[pb].addr,
362 				    ef->progtab[pb].size);
363 				vnet_data_copy(vnet_data, shdr[i].sh_size);
364 				ef->progtab[pb].addr = vnet_data;
365 #endif
366 			}
367 
368 			/* Update all symbol values with the offset. */
369 			for (j = 0; j < ef->ddbsymcnt; j++) {
370 				es = &ef->ddbsymtab[j];
371 				if (es->st_shndx != i)
372 					continue;
373 				es->st_value += (Elf_Addr)ef->progtab[pb].addr;
374 			}
375 			pb++;
376 			break;
377 		case SHT_REL:
378 			ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
379 			ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
380 			ef->reltab[rl].sec = shdr[i].sh_info;
381 			rl++;
382 			break;
383 		case SHT_RELA:
384 			ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
385 			ef->relatab[ra].nrela =
386 			    shdr[i].sh_size / sizeof(Elf_Rela);
387 			ef->relatab[ra].sec = shdr[i].sh_info;
388 			ra++;
389 			break;
390 		}
391 	}
392 	if (pb != ef->nprogtab)
393 		panic("lost progbits");
394 	if (rl != ef->nreltab)
395 		panic("lost reltab");
396 	if (ra != ef->nrelatab)
397 		panic("lost relatab");
398 
399 	/* Local intra-module relocations */
400 	link_elf_reloc_local(lf);
401 
402 	*result = lf;
403 	return (0);
404 
405 out:
406 	/* preload not done this way */
407 	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
408 	return (error);
409 }
410 
411 static int
412 link_elf_link_preload_finish(linker_file_t lf)
413 {
414 	elf_file_t ef;
415 	int error;
416 
417 	ef = (elf_file_t)lf;
418 	error = relocate_file(ef);
419 	if (error)
420 		return error;
421 
422 	/* Notify MD code that a module is being loaded. */
423 	error = elf_cpu_load_file(lf);
424 	if (error)
425 		return (error);
426 
427 	return (0);
428 }
429 
430 static int
431 link_elf_load_file(linker_class_t cls, const char *filename,
432     linker_file_t *result)
433 {
434 	struct nameidata nd;
435 	struct thread *td = curthread;	/* XXX */
436 	Elf_Ehdr *hdr;
437 	Elf_Shdr *shdr;
438 	Elf_Sym *es;
439 	int nbytes, i, j;
440 	vm_offset_t mapbase;
441 	size_t mapsize;
442 	int error = 0;
443 	int resid, flags;
444 	elf_file_t ef;
445 	linker_file_t lf;
446 	int symtabindex;
447 	int symstrindex;
448 	int shstrindex;
449 	int nsym;
450 	int pb, rl, ra;
451 	int alignmask;
452 	int vfslocked;
453 
454 	shdr = NULL;
455 	lf = NULL;
456 	mapsize = 0;
457 	hdr = NULL;
458 
459 	NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
460 	flags = FREAD;
461 	error = vn_open(&nd, &flags, 0, NULL);
462 	if (error)
463 		return error;
464 	vfslocked = NDHASGIANT(&nd);
465 	NDFREE(&nd, NDF_ONLY_PNBUF);
466 	if (nd.ni_vp->v_type != VREG) {
467 		error = ENOEXEC;
468 		goto out;
469 	}
470 #ifdef MAC
471 	error = mac_kld_check_load(td->td_ucred, nd.ni_vp);
472 	if (error) {
473 		goto out;
474 	}
475 #endif
476 
477 	/* Read the elf header from the file. */
478 	hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
479 	if (hdr == NULL) {
480 		error = ENOMEM;
481 		goto out;
482 	}
483 	error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
484 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
485 	    &resid, td);
486 	if (error)
487 		goto out;
488 	if (resid != 0){
489 		error = ENOEXEC;
490 		goto out;
491 	}
492 
493 	if (!IS_ELF(*hdr)) {
494 		error = ENOEXEC;
495 		goto out;
496 	}
497 
498 	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
499 	    || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
500 		link_elf_error(filename, "Unsupported file layout");
501 		error = ENOEXEC;
502 		goto out;
503 	}
504 	if (hdr->e_ident[EI_VERSION] != EV_CURRENT
505 	    || hdr->e_version != EV_CURRENT) {
506 		link_elf_error(filename, "Unsupported file version");
507 		error = ENOEXEC;
508 		goto out;
509 	}
510 	if (hdr->e_type != ET_REL) {
511 		error = ENOSYS;
512 		goto out;
513 	}
514 	if (hdr->e_machine != ELF_TARG_MACH) {
515 		link_elf_error(filename, "Unsupported machine");
516 		error = ENOEXEC;
517 		goto out;
518 	}
519 
520 	lf = linker_make_file(filename, &link_elf_class);
521 	if (!lf) {
522 		error = ENOMEM;
523 		goto out;
524 	}
525 	ef = (elf_file_t) lf;
526 	ef->nprogtab = 0;
527 	ef->e_shdr = 0;
528 	ef->nreltab = 0;
529 	ef->nrelatab = 0;
530 
531 	/* Allocate and read in the section header */
532 	nbytes = hdr->e_shnum * hdr->e_shentsize;
533 	if (nbytes == 0 || hdr->e_shoff == 0 ||
534 	    hdr->e_shentsize != sizeof(Elf_Shdr)) {
535 		error = ENOEXEC;
536 		goto out;
537 	}
538 	shdr = malloc(nbytes, M_LINKER, M_WAITOK);
539 	if (shdr == NULL) {
540 		error = ENOMEM;
541 		goto out;
542 	}
543 	ef->e_shdr = shdr;
544 	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
545 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
546 	if (error)
547 		goto out;
548 	if (resid) {
549 		error = ENOEXEC;
550 		goto out;
551 	}
552 
553 	/* Scan the section header for information and table sizing. */
554 	nsym = 0;
555 	symtabindex = -1;
556 	symstrindex = -1;
557 	for (i = 0; i < hdr->e_shnum; i++) {
558 		if (shdr[i].sh_size == 0)
559 			continue;
560 		switch (shdr[i].sh_type) {
561 		case SHT_PROGBITS:
562 		case SHT_NOBITS:
563 			ef->nprogtab++;
564 			break;
565 		case SHT_SYMTAB:
566 			nsym++;
567 			symtabindex = i;
568 			symstrindex = shdr[i].sh_link;
569 			break;
570 		case SHT_REL:
571 			ef->nreltab++;
572 			break;
573 		case SHT_RELA:
574 			ef->nrelatab++;
575 			break;
576 		case SHT_STRTAB:
577 			break;
578 		}
579 	}
580 	if (ef->nprogtab == 0) {
581 		link_elf_error(filename, "file has no contents");
582 		error = ENOEXEC;
583 		goto out;
584 	}
585 	if (nsym != 1) {
586 		/* Only allow one symbol table for now */
587 		link_elf_error(filename, "file has no valid symbol table");
588 		error = ENOEXEC;
589 		goto out;
590 	}
591 	if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
592 	    shdr[symstrindex].sh_type != SHT_STRTAB) {
593 		link_elf_error(filename, "file has invalid symbol strings");
594 		error = ENOEXEC;
595 		goto out;
596 	}
597 
598 	/* Allocate space for tracking the load chunks */
599 	if (ef->nprogtab != 0)
600 		ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
601 		    M_LINKER, M_WAITOK | M_ZERO);
602 	if (ef->nreltab != 0)
603 		ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
604 		    M_LINKER, M_WAITOK | M_ZERO);
605 	if (ef->nrelatab != 0)
606 		ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
607 		    M_LINKER, M_WAITOK | M_ZERO);
608 	if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
609 	    (ef->nreltab != 0 && ef->reltab == NULL) ||
610 	    (ef->nrelatab != 0 && ef->relatab == NULL)) {
611 		error = ENOMEM;
612 		goto out;
613 	}
614 
615 	if (symtabindex == -1)
616 		panic("lost symbol table index");
617 	/* Allocate space for and load the symbol table */
618 	ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
619 	ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
620 	if (ef->ddbsymtab == NULL) {
621 		error = ENOMEM;
622 		goto out;
623 	}
624 	error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
625 	    shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
626 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
627 	    &resid, td);
628 	if (error)
629 		goto out;
630 	if (resid != 0){
631 		error = EINVAL;
632 		goto out;
633 	}
634 
635 	if (symstrindex == -1)
636 		panic("lost symbol string index");
637 	/* Allocate space for and load the symbol strings */
638 	ef->ddbstrcnt = shdr[symstrindex].sh_size;
639 	ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
640 	if (ef->ddbstrtab == NULL) {
641 		error = ENOMEM;
642 		goto out;
643 	}
644 	error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
645 	    shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
646 	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
647 	    &resid, td);
648 	if (error)
649 		goto out;
650 	if (resid != 0){
651 		error = EINVAL;
652 		goto out;
653 	}
654 
655 	/* Do we have a string table for the section names?  */
656 	shstrindex = -1;
657 	if (hdr->e_shstrndx != 0 &&
658 	    shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
659 		shstrindex = hdr->e_shstrndx;
660 		ef->shstrcnt = shdr[shstrindex].sh_size;
661 		ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
662 		    M_WAITOK);
663 		if (ef->shstrtab == NULL) {
664 			error = ENOMEM;
665 			goto out;
666 		}
667 		error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
668 		    shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
669 		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
670 		    &resid, td);
671 		if (error)
672 			goto out;
673 		if (resid != 0){
674 			error = EINVAL;
675 			goto out;
676 		}
677 	}
678 
679 	/* Size up code/data(progbits) and bss(nobits). */
680 	alignmask = 0;
681 	for (i = 0; i < hdr->e_shnum; i++) {
682 		if (shdr[i].sh_size == 0)
683 			continue;
684 		switch (shdr[i].sh_type) {
685 		case SHT_PROGBITS:
686 		case SHT_NOBITS:
687 			alignmask = shdr[i].sh_addralign - 1;
688 			mapsize += alignmask;
689 			mapsize &= ~alignmask;
690 			mapsize += shdr[i].sh_size;
691 			break;
692 		}
693 	}
694 
695 	/*
696 	 * We know how much space we need for the text/data/bss/etc.
697 	 * This stuff needs to be in a single chunk so that profiling etc
698 	 * can get the bounds and gdb can associate offsets with modules
699 	 */
700 	ef->object = vm_object_allocate(OBJT_DEFAULT,
701 	    round_page(mapsize) >> PAGE_SHIFT);
702 	if (ef->object == NULL) {
703 		error = ENOMEM;
704 		goto out;
705 	}
706 	ef->address = (caddr_t) vm_map_min(kernel_map);
707 
708 	/*
709 	 * In order to satisfy amd64's architectural requirements on the
710 	 * location of code and data in the kernel's address space, request a
711 	 * mapping that is above the kernel.
712 	 */
713 	mapbase = KERNBASE;
714 	error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
715 	    round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE);
716 	if (error) {
717 		vm_object_deallocate(ef->object);
718 		ef->object = 0;
719 		goto out;
720 	}
721 
722 	/* Wire the pages */
723 	error = vm_map_wire(kernel_map, mapbase,
724 	    mapbase + round_page(mapsize),
725 	    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
726 	if (error != KERN_SUCCESS) {
727 		error = ENOMEM;
728 		goto out;
729 	}
730 
731 	/* Inform the kld system about the situation */
732 	lf->address = ef->address = (caddr_t)mapbase;
733 	lf->size = mapsize;
734 
735 	/*
736 	 * Now load code/data(progbits), zero bss(nobits), allocate space for
737 	 * and load relocs
738 	 */
739 	pb = 0;
740 	rl = 0;
741 	ra = 0;
742 	alignmask = 0;
743 	for (i = 0; i < hdr->e_shnum; i++) {
744 		if (shdr[i].sh_size == 0)
745 			continue;
746 		switch (shdr[i].sh_type) {
747 		case SHT_PROGBITS:
748 		case SHT_NOBITS:
749 			alignmask = shdr[i].sh_addralign - 1;
750 			mapbase += alignmask;
751 			mapbase &= ~alignmask;
752 			if (ef->shstrtab && shdr[i].sh_name != 0)
753 				ef->progtab[pb].name =
754 				    ef->shstrtab + shdr[i].sh_name;
755 			else if (shdr[i].sh_type == SHT_PROGBITS)
756 				ef->progtab[pb].name = "<<PROGBITS>>";
757 			else
758 				ef->progtab[pb].name = "<<NOBITS>>";
759 			if (ef->progtab[pb].name != NULL &&
760 			    !strcmp(ef->progtab[pb].name, "set_pcpu"))
761 				ef->progtab[pb].addr =
762 				    dpcpu_alloc(shdr[i].sh_size);
763 #ifdef VIMAGE
764 			else if (ef->progtab[pb].name != NULL &&
765 			    !strcmp(ef->progtab[pb].name, VNET_SETNAME))
766 				ef->progtab[pb].addr =
767 				    vnet_data_alloc(shdr[i].sh_size);
768 #endif
769 			else
770 				ef->progtab[pb].addr =
771 				    (void *)(uintptr_t)mapbase;
772 			if (ef->progtab[pb].addr == NULL) {
773 				error = ENOSPC;
774 				goto out;
775 			}
776 			ef->progtab[pb].size = shdr[i].sh_size;
777 			ef->progtab[pb].sec = i;
778 			if (shdr[i].sh_type == SHT_PROGBITS) {
779 				error = vn_rdwr(UIO_READ, nd.ni_vp,
780 				    ef->progtab[pb].addr,
781 				    shdr[i].sh_size, shdr[i].sh_offset,
782 				    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
783 				    NOCRED, &resid, td);
784 				if (error)
785 					goto out;
786 				if (resid != 0){
787 					error = EINVAL;
788 					goto out;
789 				}
790 				/* Initialize the per-cpu or vnet area. */
791 				if (ef->progtab[pb].addr != (void *)mapbase &&
792 				    !strcmp(ef->progtab[pb].name, "set_pcpu"))
793 					dpcpu_copy(ef->progtab[pb].addr,
794 					    shdr[i].sh_size);
795 #ifdef VIMAGE
796 				else if (ef->progtab[pb].addr !=
797 				    (void *)mapbase &&
798 				    !strcmp(ef->progtab[pb].name, VNET_SETNAME))
799 					vnet_data_copy(ef->progtab[pb].addr,
800 					    shdr[i].sh_size);
801 #endif
802 			} else
803 				bzero(ef->progtab[pb].addr, shdr[i].sh_size);
804 
805 			/* Update all symbol values with the offset. */
806 			for (j = 0; j < ef->ddbsymcnt; j++) {
807 				es = &ef->ddbsymtab[j];
808 				if (es->st_shndx != i)
809 					continue;
810 				es->st_value += (Elf_Addr)ef->progtab[pb].addr;
811 			}
812 			mapbase += shdr[i].sh_size;
813 			pb++;
814 			break;
815 		case SHT_REL:
816 			ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
817 			    M_WAITOK);
818 			ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
819 			ef->reltab[rl].sec = shdr[i].sh_info;
820 			error = vn_rdwr(UIO_READ, nd.ni_vp,
821 			    (void *)ef->reltab[rl].rel,
822 			    shdr[i].sh_size, shdr[i].sh_offset,
823 			    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
824 			    &resid, td);
825 			if (error)
826 				goto out;
827 			if (resid != 0){
828 				error = EINVAL;
829 				goto out;
830 			}
831 			rl++;
832 			break;
833 		case SHT_RELA:
834 			ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
835 			    M_WAITOK);
836 			ef->relatab[ra].nrela =
837 			    shdr[i].sh_size / sizeof(Elf_Rela);
838 			ef->relatab[ra].sec = shdr[i].sh_info;
839 			error = vn_rdwr(UIO_READ, nd.ni_vp,
840 			    (void *)ef->relatab[ra].rela,
841 			    shdr[i].sh_size, shdr[i].sh_offset,
842 			    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
843 			    &resid, td);
844 			if (error)
845 				goto out;
846 			if (resid != 0){
847 				error = EINVAL;
848 				goto out;
849 			}
850 			ra++;
851 			break;
852 		}
853 	}
854 	if (pb != ef->nprogtab)
855 		panic("lost progbits");
856 	if (rl != ef->nreltab)
857 		panic("lost reltab");
858 	if (ra != ef->nrelatab)
859 		panic("lost relatab");
860 	if (mapbase != (vm_offset_t)ef->address + mapsize)
861 		panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
862 		    (u_long)mapbase, ef->address, (u_long)mapsize,
863 		    (u_long)(vm_offset_t)ef->address + mapsize);
864 
865 	/* Local intra-module relocations */
866 	link_elf_reloc_local(lf);
867 
868 	/* Pull in dependencies */
869 	VOP_UNLOCK(nd.ni_vp, 0);
870 	error = linker_load_dependencies(lf);
871 	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
872 	if (error)
873 		goto out;
874 
875 	/* External relocations */
876 	error = relocate_file(ef);
877 	if (error)
878 		goto out;
879 
880 	/* Notify MD code that a module is being loaded. */
881 	error = elf_cpu_load_file(lf);
882 	if (error)
883 		goto out;
884 
885 	*result = lf;
886 
887 out:
888 	VOP_UNLOCK(nd.ni_vp, 0);
889 	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
890 	VFS_UNLOCK_GIANT(vfslocked);
891 	if (error && lf)
892 		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
893 	if (hdr)
894 		free(hdr, M_LINKER);
895 
896 	return error;
897 }
898 
899 static void
900 link_elf_unload_file(linker_file_t file)
901 {
902 	elf_file_t ef = (elf_file_t) file;
903 	int i;
904 
905 	/* Notify MD code that a module is being unloaded. */
906 	elf_cpu_unload_file(file);
907 
908 	if (ef->progtab) {
909 		for (i = 0; i < ef->nprogtab; i++) {
910 			if (ef->progtab[i].size == 0)
911 				continue;
912 			if (ef->progtab[i].name == NULL)
913 				continue;
914 			if (!strcmp(ef->progtab[i].name, "set_pcpu"))
915 				dpcpu_free(ef->progtab[i].addr,
916 				    ef->progtab[i].size);
917 #ifdef VIMAGE
918 			else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
919 				vnet_data_free(ef->progtab[i].addr,
920 				    ef->progtab[i].size);
921 #endif
922 		}
923 	}
924 	if (ef->preloaded) {
925 		if (ef->reltab)
926 			free(ef->reltab, M_LINKER);
927 		if (ef->relatab)
928 			free(ef->relatab, M_LINKER);
929 		if (ef->progtab)
930 			free(ef->progtab, M_LINKER);
931 		if (ef->ctftab)
932 			free(ef->ctftab, M_LINKER);
933 		if (ef->ctfoff)
934 			free(ef->ctfoff, M_LINKER);
935 		if (ef->typoff)
936 			free(ef->typoff, M_LINKER);
937 		if (file->filename != NULL)
938 			preload_delete_name(file->filename);
939 		/* XXX reclaim module memory? */
940 		return;
941 	}
942 
943 	for (i = 0; i < ef->nreltab; i++)
944 		if (ef->reltab[i].rel)
945 			free(ef->reltab[i].rel, M_LINKER);
946 	for (i = 0; i < ef->nrelatab; i++)
947 		if (ef->relatab[i].rela)
948 			free(ef->relatab[i].rela, M_LINKER);
949 	if (ef->reltab)
950 		free(ef->reltab, M_LINKER);
951 	if (ef->relatab)
952 		free(ef->relatab, M_LINKER);
953 	if (ef->progtab)
954 		free(ef->progtab, M_LINKER);
955 
956 	if (ef->object) {
957 		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
958 		    (vm_offset_t) ef->address +
959 		    (ef->object->size << PAGE_SHIFT));
960 	}
961 	if (ef->e_shdr)
962 		free(ef->e_shdr, M_LINKER);
963 	if (ef->ddbsymtab)
964 		free(ef->ddbsymtab, M_LINKER);
965 	if (ef->ddbstrtab)
966 		free(ef->ddbstrtab, M_LINKER);
967 	if (ef->shstrtab)
968 		free(ef->shstrtab, M_LINKER);
969 	if (ef->ctftab)
970 		free(ef->ctftab, M_LINKER);
971 	if (ef->ctfoff)
972 		free(ef->ctfoff, M_LINKER);
973 	if (ef->typoff)
974 		free(ef->typoff, M_LINKER);
975 }
976 
977 static const char *
978 symbol_name(elf_file_t ef, Elf_Size r_info)
979 {
980 	const Elf_Sym *ref;
981 
982 	if (ELF_R_SYM(r_info)) {
983 		ref = ef->ddbsymtab + ELF_R_SYM(r_info);
984 		return ef->ddbstrtab + ref->st_name;
985 	} else
986 		return NULL;
987 }
988 
989 static Elf_Addr
990 findbase(elf_file_t ef, int sec)
991 {
992 	int i;
993 	Elf_Addr base = 0;
994 
995 	for (i = 0; i < ef->nprogtab; i++) {
996 		if (sec == ef->progtab[i].sec) {
997 			base = (Elf_Addr)ef->progtab[i].addr;
998 			break;
999 		}
1000 	}
1001 	return base;
1002 }
1003 
1004 static int
1005 relocate_file(elf_file_t ef)
1006 {
1007 	const Elf_Rel *rellim;
1008 	const Elf_Rel *rel;
1009 	const Elf_Rela *relalim;
1010 	const Elf_Rela *rela;
1011 	const char *symname;
1012 	const Elf_Sym *sym;
1013 	int i;
1014 	Elf_Size symidx;
1015 	Elf_Addr base;
1016 
1017 
1018 	/* Perform relocations without addend if there are any: */
1019 	for (i = 0; i < ef->nreltab; i++) {
1020 		rel = ef->reltab[i].rel;
1021 		if (rel == NULL)
1022 			panic("lost a reltab!");
1023 		rellim = rel + ef->reltab[i].nrel;
1024 		base = findbase(ef, ef->reltab[i].sec);
1025 		if (base == 0)
1026 			panic("lost base for reltab");
1027 		for ( ; rel < rellim; rel++) {
1028 			symidx = ELF_R_SYM(rel->r_info);
1029 			if (symidx >= ef->ddbsymcnt)
1030 				continue;
1031 			sym = ef->ddbsymtab + symidx;
1032 			/* Local relocs are already done */
1033 			if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1034 				continue;
1035 			if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1036 			    elf_obj_lookup)) {
1037 				symname = symbol_name(ef, rel->r_info);
1038 				printf("link_elf_obj: symbol %s undefined\n",
1039 				    symname);
1040 				return ENOENT;
1041 			}
1042 		}
1043 	}
1044 
1045 	/* Perform relocations with addend if there are any: */
1046 	for (i = 0; i < ef->nrelatab; i++) {
1047 		rela = ef->relatab[i].rela;
1048 		if (rela == NULL)
1049 			panic("lost a relatab!");
1050 		relalim = rela + ef->relatab[i].nrela;
1051 		base = findbase(ef, ef->relatab[i].sec);
1052 		if (base == 0)
1053 			panic("lost base for relatab");
1054 		for ( ; rela < relalim; rela++) {
1055 			symidx = ELF_R_SYM(rela->r_info);
1056 			if (symidx >= ef->ddbsymcnt)
1057 				continue;
1058 			sym = ef->ddbsymtab + symidx;
1059 			/* Local relocs are already done */
1060 			if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1061 				continue;
1062 			if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1063 			    elf_obj_lookup)) {
1064 				symname = symbol_name(ef, rela->r_info);
1065 				printf("link_elf_obj: symbol %s undefined\n",
1066 				    symname);
1067 				return ENOENT;
1068 			}
1069 		}
1070 	}
1071 
1072 	return 0;
1073 }
1074 
1075 static int
1076 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1077 {
1078 	elf_file_t ef = (elf_file_t) lf;
1079 	const Elf_Sym *symp;
1080 	const char *strp;
1081 	int i;
1082 
1083 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1084 		strp = ef->ddbstrtab + symp->st_name;
1085 		if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1086 			*sym = (c_linker_sym_t) symp;
1087 			return 0;
1088 		}
1089 	}
1090 	return ENOENT;
1091 }
1092 
1093 static int
1094 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1095     linker_symval_t *symval)
1096 {
1097 	elf_file_t ef = (elf_file_t) lf;
1098 	const Elf_Sym *es = (const Elf_Sym*) sym;
1099 
1100 	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1101 		symval->name = ef->ddbstrtab + es->st_name;
1102 		symval->value = (caddr_t)es->st_value;
1103 		symval->size = es->st_size;
1104 		return 0;
1105 	}
1106 	return ENOENT;
1107 }
1108 
1109 static int
1110 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1111     c_linker_sym_t *sym, long *diffp)
1112 {
1113 	elf_file_t ef = (elf_file_t) lf;
1114 	u_long off = (uintptr_t) (void *) value;
1115 	u_long diff = off;
1116 	u_long st_value;
1117 	const Elf_Sym *es;
1118 	const Elf_Sym *best = 0;
1119 	int i;
1120 
1121 	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1122 		if (es->st_name == 0)
1123 			continue;
1124 		st_value = es->st_value;
1125 		if (off >= st_value) {
1126 			if (off - st_value < diff) {
1127 				diff = off - st_value;
1128 				best = es;
1129 				if (diff == 0)
1130 					break;
1131 			} else if (off - st_value == diff) {
1132 				best = es;
1133 			}
1134 		}
1135 	}
1136 	if (best == 0)
1137 		*diffp = off;
1138 	else
1139 		*diffp = diff;
1140 	*sym = (c_linker_sym_t) best;
1141 
1142 	return 0;
1143 }
1144 
1145 /*
1146  * Look up a linker set on an ELF system.
1147  */
1148 static int
1149 link_elf_lookup_set(linker_file_t lf, const char *name,
1150     void ***startp, void ***stopp, int *countp)
1151 {
1152 	elf_file_t ef = (elf_file_t)lf;
1153 	void **start, **stop;
1154 	int i, count;
1155 
1156 	/* Relative to section number */
1157 	for (i = 0; i < ef->nprogtab; i++) {
1158 		if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1159 		    strcmp(ef->progtab[i].name + 4, name) == 0) {
1160 			start  = (void **)ef->progtab[i].addr;
1161 			stop = (void **)((char *)ef->progtab[i].addr +
1162 			    ef->progtab[i].size);
1163 			count = stop - start;
1164 			if (startp)
1165 				*startp = start;
1166 			if (stopp)
1167 				*stopp = stop;
1168 			if (countp)
1169 				*countp = count;
1170 			return (0);
1171 		}
1172 	}
1173 	return (ESRCH);
1174 }
1175 
1176 static int
1177 link_elf_each_function_name(linker_file_t file,
1178     int (*callback)(const char *, void *), void *opaque)
1179 {
1180 	elf_file_t ef = (elf_file_t)file;
1181 	const Elf_Sym *symp;
1182 	int i, error;
1183 
1184 	/* Exhaustive search */
1185 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1186 		if (symp->st_value != 0 &&
1187 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1188 			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1189 			if (error)
1190 				return (error);
1191 		}
1192 	}
1193 	return (0);
1194 }
1195 
1196 static int
1197 link_elf_each_function_nameval(linker_file_t file,
1198     linker_function_nameval_callback_t callback, void *opaque)
1199 {
1200 	linker_symval_t symval;
1201 	elf_file_t ef = (elf_file_t)file;
1202 	const Elf_Sym* symp;
1203 	int i, error;
1204 
1205 	/* Exhaustive search */
1206 	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1207 		if (symp->st_value != 0 &&
1208 		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1209 			error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1210 			if (error)
1211 				return (error);
1212 			error = callback(file, i, &symval, opaque);
1213 			if (error)
1214 				return (error);
1215 		}
1216 	}
1217 	return (0);
1218 }
1219 
1220 /*
1221  * Symbol lookup function that can be used when the symbol index is known (ie
1222  * in relocations). It uses the symbol index instead of doing a fully fledged
1223  * hash table based lookup when such is valid. For example for local symbols.
1224  * This is not only more efficient, it's also more correct. It's not always
1225  * the case that the symbol can be found through the hash table.
1226  */
1227 static Elf_Addr
1228 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1229 {
1230 	elf_file_t ef = (elf_file_t)lf;
1231 	const Elf_Sym *sym;
1232 	const char *symbol;
1233 	Elf_Addr ret;
1234 
1235 	/* Don't even try to lookup the symbol if the index is bogus. */
1236 	if (symidx >= ef->ddbsymcnt)
1237 		return (0);
1238 
1239 	sym = ef->ddbsymtab + symidx;
1240 
1241 	/* Quick answer if there is a definition included. */
1242 	if (sym->st_shndx != SHN_UNDEF)
1243 		return (sym->st_value);
1244 
1245 	/* If we get here, then it is undefined and needs a lookup. */
1246 	switch (ELF_ST_BIND(sym->st_info)) {
1247 	case STB_LOCAL:
1248 		/* Local, but undefined? huh? */
1249 		return (0);
1250 
1251 	case STB_GLOBAL:
1252 		/* Relative to Data or Function name */
1253 		symbol = ef->ddbstrtab + sym->st_name;
1254 
1255 		/* Force a lookup failure if the symbol name is bogus. */
1256 		if (*symbol == 0)
1257 			return (0);
1258 		ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1259 		return ret;
1260 
1261 	case STB_WEAK:
1262 		printf("link_elf_obj: Weak symbols not supported\n");
1263 		return (0);
1264 
1265 	default:
1266 		return (0);
1267 	}
1268 }
1269 
1270 static void
1271 link_elf_fix_link_set(elf_file_t ef)
1272 {
1273 	static const char startn[] = "__start_";
1274 	static const char stopn[] = "__stop_";
1275 	Elf_Sym *sym;
1276 	const char *sym_name, *linkset_name;
1277 	Elf_Addr startp, stopp;
1278 	Elf_Size symidx;
1279 	int start, i;
1280 
1281 	startp = stopp = 0;
1282 	for (symidx = 1 /* zero entry is special */;
1283 		symidx < ef->ddbsymcnt; symidx++) {
1284 		sym = ef->ddbsymtab + symidx;
1285 		if (sym->st_shndx != SHN_UNDEF)
1286 			continue;
1287 
1288 		sym_name = ef->ddbstrtab + sym->st_name;
1289 		if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1290 			start = 1;
1291 			linkset_name = sym_name + sizeof(startn) - 1;
1292 		}
1293 		else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1294 			start = 0;
1295 			linkset_name = sym_name + sizeof(stopn) - 1;
1296 		}
1297 		else
1298 			continue;
1299 
1300 		for (i = 0; i < ef->nprogtab; i++) {
1301 			if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1302 				startp = (Elf_Addr)ef->progtab[i].addr;
1303 				stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1304 				break;
1305 			}
1306 		}
1307 		if (i == ef->nprogtab)
1308 			continue;
1309 
1310 		sym->st_value = start ? startp : stopp;
1311 		sym->st_shndx = i;
1312 	}
1313 }
1314 
1315 static void
1316 link_elf_reloc_local(linker_file_t lf)
1317 {
1318 	elf_file_t ef = (elf_file_t)lf;
1319 	const Elf_Rel *rellim;
1320 	const Elf_Rel *rel;
1321 	const Elf_Rela *relalim;
1322 	const Elf_Rela *rela;
1323 	const Elf_Sym *sym;
1324 	Elf_Addr base;
1325 	int i;
1326 	Elf_Size symidx;
1327 
1328 	link_elf_fix_link_set(ef);
1329 
1330 	/* Perform relocations without addend if there are any: */
1331 	for (i = 0; i < ef->nreltab; i++) {
1332 		rel = ef->reltab[i].rel;
1333 		if (rel == NULL)
1334 			panic("lost a reltab!");
1335 		rellim = rel + ef->reltab[i].nrel;
1336 		base = findbase(ef, ef->reltab[i].sec);
1337 		if (base == 0)
1338 			panic("lost base for reltab");
1339 		for ( ; rel < rellim; rel++) {
1340 			symidx = ELF_R_SYM(rel->r_info);
1341 			if (symidx >= ef->ddbsymcnt)
1342 				continue;
1343 			sym = ef->ddbsymtab + symidx;
1344 			/* Only do local relocs */
1345 			if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1346 				continue;
1347 			elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1348 			    elf_obj_lookup);
1349 		}
1350 	}
1351 
1352 	/* Perform relocations with addend if there are any: */
1353 	for (i = 0; i < ef->nrelatab; i++) {
1354 		rela = ef->relatab[i].rela;
1355 		if (rela == NULL)
1356 			panic("lost a relatab!");
1357 		relalim = rela + ef->relatab[i].nrela;
1358 		base = findbase(ef, ef->relatab[i].sec);
1359 		if (base == 0)
1360 			panic("lost base for relatab");
1361 		for ( ; rela < relalim; rela++) {
1362 			symidx = ELF_R_SYM(rela->r_info);
1363 			if (symidx >= ef->ddbsymcnt)
1364 				continue;
1365 			sym = ef->ddbsymtab + symidx;
1366 			/* Only do local relocs */
1367 			if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1368 				continue;
1369 			elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1370 			    elf_obj_lookup);
1371 		}
1372 	}
1373 }
1374 
1375 static long
1376 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1377 {
1378     elf_file_t ef = (elf_file_t)lf;
1379 
1380     *symtab = ef->ddbsymtab;
1381 
1382     if (*symtab == NULL)
1383         return (0);
1384 
1385     return (ef->ddbsymcnt);
1386 }
1387 
1388 static long
1389 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1390 {
1391     elf_file_t ef = (elf_file_t)lf;
1392 
1393     *strtab = ef->ddbstrtab;
1394 
1395     if (*strtab == NULL)
1396         return (0);
1397 
1398     return (ef->ddbstrcnt);
1399 }
1400