link_elf_obj.c revision 329191 
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: stable/11/sys/kern/link_elf_obj.c 329191 2018-02-13 04:10:10Z kevans $");
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 <sys/zlib.h>
64#endif
65
66#include "linker_if.h"
67
68typedef struct {
69	void		*addr;
70	Elf_Off		size;
71	int		flags;
72	int		sec;	/* Original section */
73	char		*name;
74} Elf_progent;
75
76typedef struct {
77	Elf_Rel		*rel;
78	int		nrel;
79	int		sec;
80} Elf_relent;
81
82typedef struct {
83	Elf_Rela	*rela;
84	int		nrela;
85	int		sec;
86} Elf_relaent;
87
88
89typedef 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
124static int	link_elf_link_preload(linker_class_t cls,
125		    const char *, linker_file_t *);
126static int	link_elf_link_preload_finish(linker_file_t);
127static int	link_elf_load_file(linker_class_t, const char *, linker_file_t *);
128static int	link_elf_lookup_symbol(linker_file_t, const char *,
129		    c_linker_sym_t *);
130static int	link_elf_symbol_values(linker_file_t, c_linker_sym_t,
131		    linker_symval_t *);
132static int	link_elf_search_symbol(linker_file_t, caddr_t value,
133		    c_linker_sym_t *sym, long *diffp);
134
135static void	link_elf_unload_file(linker_file_t);
136static int	link_elf_lookup_set(linker_file_t, const char *,
137		    void ***, void ***, int *);
138static int	link_elf_each_function_name(linker_file_t,
139		    int (*)(const char *, void *), void *);
140static int	link_elf_each_function_nameval(linker_file_t,
141				linker_function_nameval_callback_t,
142				void *);
143static int	link_elf_reloc_local(linker_file_t);
144static long	link_elf_symtab_get(linker_file_t, const Elf_Sym **);
145static long	link_elf_strtab_get(linker_file_t, caddr_t *);
146
147static int	elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
148		    Elf_Addr *);
149
150static kobj_method_t link_elf_methods[] = {
151	KOBJMETHOD(linker_lookup_symbol,	link_elf_lookup_symbol),
152	KOBJMETHOD(linker_symbol_values,	link_elf_symbol_values),
153	KOBJMETHOD(linker_search_symbol,	link_elf_search_symbol),
154	KOBJMETHOD(linker_unload,		link_elf_unload_file),
155	KOBJMETHOD(linker_load_file,		link_elf_load_file),
156	KOBJMETHOD(linker_link_preload,		link_elf_link_preload),
157	KOBJMETHOD(linker_link_preload_finish,	link_elf_link_preload_finish),
158	KOBJMETHOD(linker_lookup_set,		link_elf_lookup_set),
159	KOBJMETHOD(linker_each_function_name,	link_elf_each_function_name),
160	KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
161	KOBJMETHOD(linker_ctf_get,		link_elf_ctf_get),
162	KOBJMETHOD(linker_symtab_get, 		link_elf_symtab_get),
163	KOBJMETHOD(linker_strtab_get, 		link_elf_strtab_get),
164	{ 0, 0 }
165};
166
167static struct linker_class link_elf_class = {
168#if ELF_TARG_CLASS == ELFCLASS32
169	"elf32_obj",
170#else
171	"elf64_obj",
172#endif
173	link_elf_methods, sizeof(struct elf_file)
174};
175
176static int	relocate_file(elf_file_t ef);
177static void	elf_obj_cleanup_globals_cache(elf_file_t);
178
179static void
180link_elf_error(const char *filename, const char *s)
181{
182	if (filename == NULL)
183		printf("kldload: %s\n", s);
184	else
185		printf("kldload: %s: %s\n", filename, s);
186}
187
188static void
189link_elf_init(void *arg)
190{
191
192	linker_add_class(&link_elf_class);
193}
194
195SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
196
197static int
198link_elf_link_preload(linker_class_t cls, const char *filename,
199    linker_file_t *result)
200{
201	Elf_Ehdr *hdr;
202	Elf_Shdr *shdr;
203	Elf_Sym *es;
204	void *modptr, *baseptr, *sizeptr;
205	char *type;
206	elf_file_t ef;
207	linker_file_t lf;
208	Elf_Addr off;
209	int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
210
211	/* Look to see if we have the file preloaded */
212	modptr = preload_search_by_name(filename);
213	if (modptr == NULL)
214		return ENOENT;
215
216	type = (char *)preload_search_info(modptr, MODINFO_TYPE);
217	baseptr = preload_search_info(modptr, MODINFO_ADDR);
218	sizeptr = preload_search_info(modptr, MODINFO_SIZE);
219	hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
220	    MODINFOMD_ELFHDR);
221	shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
222	    MODINFOMD_SHDR);
223	if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
224	    " obj module") != 0 &&
225	    strcmp(type, "elf obj module") != 0)) {
226		return (EFTYPE);
227	}
228	if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
229	    shdr == NULL)
230		return (EINVAL);
231
232	lf = linker_make_file(filename, &link_elf_class);
233	if (lf == NULL)
234		return (ENOMEM);
235
236	ef = (elf_file_t)lf;
237	ef->preloaded = 1;
238	ef->address = *(caddr_t *)baseptr;
239	lf->address = *(caddr_t *)baseptr;
240	lf->size = *(size_t *)sizeptr;
241
242	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
243	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
244	    hdr->e_ident[EI_VERSION] != EV_CURRENT ||
245	    hdr->e_version != EV_CURRENT ||
246	    hdr->e_type != ET_REL ||
247	    hdr->e_machine != ELF_TARG_MACH) {
248		error = EFTYPE;
249		goto out;
250	}
251	ef->e_shdr = shdr;
252
253	/* Scan the section header for information and table sizing. */
254	symtabindex = -1;
255	symstrindex = -1;
256	for (i = 0; i < hdr->e_shnum; i++) {
257		switch (shdr[i].sh_type) {
258		case SHT_PROGBITS:
259		case SHT_NOBITS:
260#ifdef __amd64__
261		case SHT_X86_64_UNWIND:
262#endif
263			ef->nprogtab++;
264			break;
265		case SHT_SYMTAB:
266			symtabindex = i;
267			symstrindex = shdr[i].sh_link;
268			break;
269		case SHT_REL:
270			ef->nreltab++;
271			break;
272		case SHT_RELA:
273			ef->nrelatab++;
274			break;
275		}
276	}
277
278	shstrindex = hdr->e_shstrndx;
279	if (ef->nprogtab == 0 || symstrindex < 0 ||
280	    symstrindex >= hdr->e_shnum ||
281	    shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
282	    shstrindex >= hdr->e_shnum ||
283	    shdr[shstrindex].sh_type != SHT_STRTAB) {
284		printf("%s: bad/missing section headers\n", filename);
285		error = ENOEXEC;
286		goto out;
287	}
288
289	/* Allocate space for tracking the load chunks */
290	if (ef->nprogtab != 0)
291		ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
292		    M_LINKER, M_WAITOK | M_ZERO);
293	if (ef->nreltab != 0)
294		ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
295		    M_LINKER, M_WAITOK | M_ZERO);
296	if (ef->nrelatab != 0)
297		ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
298		    M_LINKER, M_WAITOK | M_ZERO);
299	if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
300	    (ef->nreltab != 0 && ef->reltab == NULL) ||
301	    (ef->nrelatab != 0 && ef->relatab == NULL)) {
302		error = ENOMEM;
303		goto out;
304	}
305
306	/* XXX, relocate the sh_addr fields saved by the loader. */
307	off = 0;
308	for (i = 0; i < hdr->e_shnum; i++) {
309		if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
310			off = shdr[i].sh_addr;
311	}
312	for (i = 0; i < hdr->e_shnum; i++) {
313		if (shdr[i].sh_addr != 0)
314			shdr[i].sh_addr = shdr[i].sh_addr - off +
315			    (Elf_Addr)ef->address;
316	}
317
318	ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
319	ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
320	ef->ddbstrcnt = shdr[symstrindex].sh_size;
321	ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
322	ef->shstrcnt = shdr[shstrindex].sh_size;
323	ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
324
325	/* Now fill out progtab and the relocation tables. */
326	pb = 0;
327	rl = 0;
328	ra = 0;
329	for (i = 0; i < hdr->e_shnum; i++) {
330		switch (shdr[i].sh_type) {
331		case SHT_PROGBITS:
332		case SHT_NOBITS:
333#ifdef __amd64__
334		case SHT_X86_64_UNWIND:
335#endif
336			ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
337			if (shdr[i].sh_type == SHT_PROGBITS)
338				ef->progtab[pb].name = "<<PROGBITS>>";
339#ifdef __amd64__
340			else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
341				ef->progtab[pb].name = "<<UNWIND>>";
342#endif
343			else
344				ef->progtab[pb].name = "<<NOBITS>>";
345			ef->progtab[pb].size = shdr[i].sh_size;
346			ef->progtab[pb].sec = i;
347			if (ef->shstrtab && shdr[i].sh_name != 0)
348				ef->progtab[pb].name =
349				    ef->shstrtab + shdr[i].sh_name;
350			if (ef->progtab[pb].name != NULL &&
351			    !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
352				void *dpcpu;
353
354				dpcpu = dpcpu_alloc(shdr[i].sh_size);
355				if (dpcpu == NULL) {
356					error = ENOSPC;
357					goto out;
358				}
359				memcpy(dpcpu, ef->progtab[pb].addr,
360				    ef->progtab[pb].size);
361				dpcpu_copy(dpcpu, shdr[i].sh_size);
362				ef->progtab[pb].addr = dpcpu;
363#ifdef VIMAGE
364			} else if (ef->progtab[pb].name != NULL &&
365			    !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
366				void *vnet_data;
367
368				vnet_data = vnet_data_alloc(shdr[i].sh_size);
369				if (vnet_data == NULL) {
370					error = ENOSPC;
371					goto out;
372				}
373				memcpy(vnet_data, ef->progtab[pb].addr,
374				    ef->progtab[pb].size);
375				vnet_data_copy(vnet_data, shdr[i].sh_size);
376				ef->progtab[pb].addr = vnet_data;
377#endif
378			} else if (ef->progtab[pb].name != NULL &&
379			    !strcmp(ef->progtab[pb].name, ".ctors")) {
380				lf->ctors_addr = ef->progtab[pb].addr;
381				lf->ctors_size = shdr[i].sh_size;
382			}
383
384			/* Update all symbol values with the offset. */
385			for (j = 0; j < ef->ddbsymcnt; j++) {
386				es = &ef->ddbsymtab[j];
387				if (es->st_shndx != i)
388					continue;
389				es->st_value += (Elf_Addr)ef->progtab[pb].addr;
390			}
391			pb++;
392			break;
393		case SHT_REL:
394			ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
395			ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
396			ef->reltab[rl].sec = shdr[i].sh_info;
397			rl++;
398			break;
399		case SHT_RELA:
400			ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
401			ef->relatab[ra].nrela =
402			    shdr[i].sh_size / sizeof(Elf_Rela);
403			ef->relatab[ra].sec = shdr[i].sh_info;
404			ra++;
405			break;
406		}
407	}
408	if (pb != ef->nprogtab) {
409		printf("%s: lost progbits\n", filename);
410		error = ENOEXEC;
411		goto out;
412	}
413	if (rl != ef->nreltab) {
414		printf("%s: lost reltab\n", filename);
415		error = ENOEXEC;
416		goto out;
417	}
418	if (ra != ef->nrelatab) {
419		printf("%s: lost relatab\n", filename);
420		error = ENOEXEC;
421		goto out;
422	}
423
424	/* Local intra-module relocations */
425	error = link_elf_reloc_local(lf);
426	if (error != 0)
427		goto out;
428
429	*result = lf;
430	return (0);
431
432out:
433	/* preload not done this way */
434	linker_file_unload(lf, LINKER_UNLOAD_FORCE);
435	return (error);
436}
437
438static void
439link_elf_invoke_ctors(caddr_t addr, size_t size)
440{
441	void (**ctor)(void);
442	size_t i, cnt;
443
444	if (addr == NULL || size == 0)
445		return;
446	cnt = size / sizeof(*ctor);
447	ctor = (void *)addr;
448	for (i = 0; i < cnt; i++) {
449		if (ctor[i] != NULL)
450			(*ctor[i])();
451	}
452}
453
454static int
455link_elf_link_preload_finish(linker_file_t lf)
456{
457	elf_file_t ef;
458	int error;
459
460	ef = (elf_file_t)lf;
461	error = relocate_file(ef);
462	if (error)
463		return error;
464
465	/* Notify MD code that a module is being loaded. */
466	error = elf_cpu_load_file(lf);
467	if (error)
468		return (error);
469
470	/* Invoke .ctors */
471	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
472	return (0);
473}
474
475static int
476link_elf_load_file(linker_class_t cls, const char *filename,
477    linker_file_t *result)
478{
479	struct nameidata nd;
480	struct thread *td = curthread;	/* XXX */
481	Elf_Ehdr *hdr;
482	Elf_Shdr *shdr;
483	Elf_Sym *es;
484	int nbytes, i, j;
485	vm_offset_t mapbase;
486	size_t mapsize;
487	int error = 0;
488	ssize_t resid;
489	int flags;
490	elf_file_t ef;
491	linker_file_t lf;
492	int symtabindex;
493	int symstrindex;
494	int shstrindex;
495	int nsym;
496	int pb, rl, ra;
497	int alignmask;
498
499	shdr = NULL;
500	lf = NULL;
501	mapsize = 0;
502	hdr = NULL;
503
504	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
505	flags = FREAD;
506	error = vn_open(&nd, &flags, 0, NULL);
507	if (error)
508		return error;
509	NDFREE(&nd, NDF_ONLY_PNBUF);
510	if (nd.ni_vp->v_type != VREG) {
511		error = ENOEXEC;
512		goto out;
513	}
514#ifdef MAC
515	error = mac_kld_check_load(td->td_ucred, nd.ni_vp);
516	if (error) {
517		goto out;
518	}
519#endif
520
521	/* Read the elf header from the file. */
522	hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
523	error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
524	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
525	    &resid, td);
526	if (error)
527		goto out;
528	if (resid != 0){
529		error = ENOEXEC;
530		goto out;
531	}
532
533	if (!IS_ELF(*hdr)) {
534		error = ENOEXEC;
535		goto out;
536	}
537
538	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
539	    || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
540		link_elf_error(filename, "Unsupported file layout");
541		error = ENOEXEC;
542		goto out;
543	}
544	if (hdr->e_ident[EI_VERSION] != EV_CURRENT
545	    || hdr->e_version != EV_CURRENT) {
546		link_elf_error(filename, "Unsupported file version");
547		error = ENOEXEC;
548		goto out;
549	}
550	if (hdr->e_type != ET_REL) {
551		error = ENOSYS;
552		goto out;
553	}
554	if (hdr->e_machine != ELF_TARG_MACH) {
555		link_elf_error(filename, "Unsupported machine");
556		error = ENOEXEC;
557		goto out;
558	}
559
560	lf = linker_make_file(filename, &link_elf_class);
561	if (!lf) {
562		error = ENOMEM;
563		goto out;
564	}
565	ef = (elf_file_t) lf;
566	ef->nprogtab = 0;
567	ef->e_shdr = 0;
568	ef->nreltab = 0;
569	ef->nrelatab = 0;
570
571	/* Allocate and read in the section header */
572	nbytes = hdr->e_shnum * hdr->e_shentsize;
573	if (nbytes == 0 || hdr->e_shoff == 0 ||
574	    hdr->e_shentsize != sizeof(Elf_Shdr)) {
575		error = ENOEXEC;
576		goto out;
577	}
578	shdr = malloc(nbytes, M_LINKER, M_WAITOK);
579	ef->e_shdr = shdr;
580	error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
581	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
582	if (error)
583		goto out;
584	if (resid) {
585		error = ENOEXEC;
586		goto out;
587	}
588
589	/* Scan the section header for information and table sizing. */
590	nsym = 0;
591	symtabindex = -1;
592	symstrindex = -1;
593	for (i = 0; i < hdr->e_shnum; i++) {
594		if (shdr[i].sh_size == 0)
595			continue;
596		switch (shdr[i].sh_type) {
597		case SHT_PROGBITS:
598		case SHT_NOBITS:
599#ifdef __amd64__
600		case SHT_X86_64_UNWIND:
601#endif
602			ef->nprogtab++;
603			break;
604		case SHT_SYMTAB:
605			nsym++;
606			symtabindex = i;
607			symstrindex = shdr[i].sh_link;
608			break;
609		case SHT_REL:
610			ef->nreltab++;
611			break;
612		case SHT_RELA:
613			ef->nrelatab++;
614			break;
615		case SHT_STRTAB:
616			break;
617		}
618	}
619	if (ef->nprogtab == 0) {
620		link_elf_error(filename, "file has no contents");
621		error = ENOEXEC;
622		goto out;
623	}
624	if (nsym != 1) {
625		/* Only allow one symbol table for now */
626		link_elf_error(filename, "file has no valid symbol table");
627		error = ENOEXEC;
628		goto out;
629	}
630	if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
631	    shdr[symstrindex].sh_type != SHT_STRTAB) {
632		link_elf_error(filename, "file has invalid symbol strings");
633		error = ENOEXEC;
634		goto out;
635	}
636
637	/* Allocate space for tracking the load chunks */
638	if (ef->nprogtab != 0)
639		ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
640		    M_LINKER, M_WAITOK | M_ZERO);
641	if (ef->nreltab != 0)
642		ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
643		    M_LINKER, M_WAITOK | M_ZERO);
644	if (ef->nrelatab != 0)
645		ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
646		    M_LINKER, M_WAITOK | M_ZERO);
647
648	if (symtabindex == -1) {
649		link_elf_error(filename, "lost symbol table index");
650		error = ENOEXEC;
651		goto out;
652	}
653	/* Allocate space for and load the symbol table */
654	ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
655	ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
656	error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
657	    shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
658	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
659	    &resid, td);
660	if (error)
661		goto out;
662	if (resid != 0){
663		error = EINVAL;
664		goto out;
665	}
666
667	if (symstrindex == -1) {
668		link_elf_error(filename, "lost symbol string index");
669		error = ENOEXEC;
670		goto out;
671	}
672	/* Allocate space for and load the symbol strings */
673	ef->ddbstrcnt = shdr[symstrindex].sh_size;
674	ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
675	error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
676	    shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
677	    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
678	    &resid, td);
679	if (error)
680		goto out;
681	if (resid != 0){
682		error = EINVAL;
683		goto out;
684	}
685
686	/* Do we have a string table for the section names?  */
687	shstrindex = -1;
688	if (hdr->e_shstrndx != 0 &&
689	    shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
690		shstrindex = hdr->e_shstrndx;
691		ef->shstrcnt = shdr[shstrindex].sh_size;
692		ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
693		    M_WAITOK);
694		error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
695		    shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
696		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
697		    &resid, td);
698		if (error)
699			goto out;
700		if (resid != 0){
701			error = EINVAL;
702			goto out;
703		}
704	}
705
706	/* Size up code/data(progbits) and bss(nobits). */
707	alignmask = 0;
708	for (i = 0; i < hdr->e_shnum; i++) {
709		if (shdr[i].sh_size == 0)
710			continue;
711		switch (shdr[i].sh_type) {
712		case SHT_PROGBITS:
713		case SHT_NOBITS:
714#ifdef __amd64__
715		case SHT_X86_64_UNWIND:
716#endif
717			alignmask = shdr[i].sh_addralign - 1;
718			mapsize += alignmask;
719			mapsize &= ~alignmask;
720			mapsize += shdr[i].sh_size;
721			break;
722		}
723	}
724
725	/*
726	 * We know how much space we need for the text/data/bss/etc.
727	 * This stuff needs to be in a single chunk so that profiling etc
728	 * can get the bounds and gdb can associate offsets with modules
729	 */
730	ef->object = vm_object_allocate(OBJT_DEFAULT,
731	    round_page(mapsize) >> PAGE_SHIFT);
732	if (ef->object == NULL) {
733		error = ENOMEM;
734		goto out;
735	}
736	ef->address = (caddr_t) vm_map_min(kernel_map);
737
738	/*
739	 * In order to satisfy amd64's architectural requirements on the
740	 * location of code and data in the kernel's address space, request a
741	 * mapping that is above the kernel.
742	 */
743#ifdef __amd64__
744	mapbase = KERNBASE;
745#else
746	mapbase = VM_MIN_KERNEL_ADDRESS;
747#endif
748	error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
749	    round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
750	    VM_PROT_ALL, 0);
751	if (error) {
752		vm_object_deallocate(ef->object);
753		ef->object = 0;
754		goto out;
755	}
756
757	/* Wire the pages */
758	error = vm_map_wire(kernel_map, mapbase,
759	    mapbase + round_page(mapsize),
760	    VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
761	if (error != KERN_SUCCESS) {
762		error = ENOMEM;
763		goto out;
764	}
765
766	/* Inform the kld system about the situation */
767	lf->address = ef->address = (caddr_t)mapbase;
768	lf->size = mapsize;
769
770	/*
771	 * Now load code/data(progbits), zero bss(nobits), allocate space for
772	 * and load relocs
773	 */
774	pb = 0;
775	rl = 0;
776	ra = 0;
777	alignmask = 0;
778	for (i = 0; i < hdr->e_shnum; i++) {
779		if (shdr[i].sh_size == 0)
780			continue;
781		switch (shdr[i].sh_type) {
782		case SHT_PROGBITS:
783		case SHT_NOBITS:
784#ifdef __amd64__
785		case SHT_X86_64_UNWIND:
786#endif
787			alignmask = shdr[i].sh_addralign - 1;
788			mapbase += alignmask;
789			mapbase &= ~alignmask;
790			if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
791				ef->progtab[pb].name =
792				    ef->shstrtab + shdr[i].sh_name;
793				if (!strcmp(ef->progtab[pb].name, ".ctors")) {
794					lf->ctors_addr = (caddr_t)mapbase;
795					lf->ctors_size = shdr[i].sh_size;
796				}
797			} else if (shdr[i].sh_type == SHT_PROGBITS)
798				ef->progtab[pb].name = "<<PROGBITS>>";
799#ifdef __amd64__
800			else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
801				ef->progtab[pb].name = "<<UNWIND>>";
802#endif
803			else
804				ef->progtab[pb].name = "<<NOBITS>>";
805			if (ef->progtab[pb].name != NULL &&
806			    !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
807				ef->progtab[pb].addr =
808				    dpcpu_alloc(shdr[i].sh_size);
809#ifdef VIMAGE
810			else if (ef->progtab[pb].name != NULL &&
811			    !strcmp(ef->progtab[pb].name, VNET_SETNAME))
812				ef->progtab[pb].addr =
813				    vnet_data_alloc(shdr[i].sh_size);
814#endif
815			else
816				ef->progtab[pb].addr =
817				    (void *)(uintptr_t)mapbase;
818			if (ef->progtab[pb].addr == NULL) {
819				error = ENOSPC;
820				goto out;
821			}
822			ef->progtab[pb].size = shdr[i].sh_size;
823			ef->progtab[pb].sec = i;
824			if (shdr[i].sh_type == SHT_PROGBITS
825#ifdef __amd64__
826			    || shdr[i].sh_type == SHT_X86_64_UNWIND
827#endif
828			    ) {
829				error = vn_rdwr(UIO_READ, nd.ni_vp,
830				    ef->progtab[pb].addr,
831				    shdr[i].sh_size, shdr[i].sh_offset,
832				    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
833				    NOCRED, &resid, td);
834				if (error)
835					goto out;
836				if (resid != 0){
837					error = EINVAL;
838					goto out;
839				}
840				/* Initialize the per-cpu or vnet area. */
841				if (ef->progtab[pb].addr != (void *)mapbase &&
842				    !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
843					dpcpu_copy(ef->progtab[pb].addr,
844					    shdr[i].sh_size);
845#ifdef VIMAGE
846				else if (ef->progtab[pb].addr !=
847				    (void *)mapbase &&
848				    !strcmp(ef->progtab[pb].name, VNET_SETNAME))
849					vnet_data_copy(ef->progtab[pb].addr,
850					    shdr[i].sh_size);
851#endif
852			} else
853				bzero(ef->progtab[pb].addr, shdr[i].sh_size);
854
855			/* Update all symbol values with the offset. */
856			for (j = 0; j < ef->ddbsymcnt; j++) {
857				es = &ef->ddbsymtab[j];
858				if (es->st_shndx != i)
859					continue;
860				es->st_value += (Elf_Addr)ef->progtab[pb].addr;
861			}
862			mapbase += shdr[i].sh_size;
863			pb++;
864			break;
865		case SHT_REL:
866			ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
867			    M_WAITOK);
868			ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
869			ef->reltab[rl].sec = shdr[i].sh_info;
870			error = vn_rdwr(UIO_READ, nd.ni_vp,
871			    (void *)ef->reltab[rl].rel,
872			    shdr[i].sh_size, shdr[i].sh_offset,
873			    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
874			    &resid, td);
875			if (error)
876				goto out;
877			if (resid != 0){
878				error = EINVAL;
879				goto out;
880			}
881			rl++;
882			break;
883		case SHT_RELA:
884			ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
885			    M_WAITOK);
886			ef->relatab[ra].nrela =
887			    shdr[i].sh_size / sizeof(Elf_Rela);
888			ef->relatab[ra].sec = shdr[i].sh_info;
889			error = vn_rdwr(UIO_READ, nd.ni_vp,
890			    (void *)ef->relatab[ra].rela,
891			    shdr[i].sh_size, shdr[i].sh_offset,
892			    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
893			    &resid, td);
894			if (error)
895				goto out;
896			if (resid != 0){
897				error = EINVAL;
898				goto out;
899			}
900			ra++;
901			break;
902		}
903	}
904	if (pb != ef->nprogtab) {
905		link_elf_error(filename, "lost progbits");
906		error = ENOEXEC;
907		goto out;
908	}
909	if (rl != ef->nreltab) {
910		link_elf_error(filename, "lost reltab");
911		error = ENOEXEC;
912		goto out;
913	}
914	if (ra != ef->nrelatab) {
915		link_elf_error(filename, "lost relatab");
916		error = ENOEXEC;
917		goto out;
918	}
919	if (mapbase != (vm_offset_t)ef->address + mapsize) {
920		printf(
921		    "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
922		    filename != NULL ? filename : "<none>",
923		    (u_long)mapbase, ef->address, (u_long)mapsize,
924		    (u_long)(vm_offset_t)ef->address + mapsize);
925		error = ENOMEM;
926		goto out;
927	}
928
929	/* Local intra-module relocations */
930	error = link_elf_reloc_local(lf);
931	if (error != 0)
932		goto out;
933
934	/* Pull in dependencies */
935	VOP_UNLOCK(nd.ni_vp, 0);
936	error = linker_load_dependencies(lf);
937	vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
938	if (error)
939		goto out;
940
941	/* External relocations */
942	error = relocate_file(ef);
943	if (error)
944		goto out;
945
946	/* Notify MD code that a module is being loaded. */
947	error = elf_cpu_load_file(lf);
948	if (error)
949		goto out;
950
951	/* Invoke .ctors */
952	link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
953
954	*result = lf;
955
956out:
957	VOP_UNLOCK(nd.ni_vp, 0);
958	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
959	if (error && lf)
960		linker_file_unload(lf, LINKER_UNLOAD_FORCE);
961	free(hdr, M_LINKER);
962
963	return error;
964}
965
966static void
967link_elf_unload_file(linker_file_t file)
968{
969	elf_file_t ef = (elf_file_t) file;
970	int i;
971
972	/* Notify MD code that a module is being unloaded. */
973	elf_cpu_unload_file(file);
974
975	if (ef->progtab) {
976		for (i = 0; i < ef->nprogtab; i++) {
977			if (ef->progtab[i].size == 0)
978				continue;
979			if (ef->progtab[i].name == NULL)
980				continue;
981			if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
982				dpcpu_free(ef->progtab[i].addr,
983				    ef->progtab[i].size);
984#ifdef VIMAGE
985			else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
986				vnet_data_free(ef->progtab[i].addr,
987				    ef->progtab[i].size);
988#endif
989		}
990	}
991	if (ef->preloaded) {
992		free(ef->reltab, M_LINKER);
993		free(ef->relatab, M_LINKER);
994		free(ef->progtab, M_LINKER);
995		free(ef->ctftab, M_LINKER);
996		free(ef->ctfoff, M_LINKER);
997		free(ef->typoff, M_LINKER);
998		if (file->filename != NULL)
999			preload_delete_name(file->filename);
1000		/* XXX reclaim module memory? */
1001		return;
1002	}
1003
1004	for (i = 0; i < ef->nreltab; i++)
1005		free(ef->reltab[i].rel, M_LINKER);
1006	for (i = 0; i < ef->nrelatab; i++)
1007		free(ef->relatab[i].rela, M_LINKER);
1008	free(ef->reltab, M_LINKER);
1009	free(ef->relatab, M_LINKER);
1010	free(ef->progtab, M_LINKER);
1011
1012	if (ef->object) {
1013		vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1014		    (vm_offset_t) ef->address +
1015		    (ef->object->size << PAGE_SHIFT));
1016	}
1017	free(ef->e_shdr, M_LINKER);
1018	free(ef->ddbsymtab, M_LINKER);
1019	free(ef->ddbstrtab, M_LINKER);
1020	free(ef->shstrtab, M_LINKER);
1021	free(ef->ctftab, M_LINKER);
1022	free(ef->ctfoff, M_LINKER);
1023	free(ef->typoff, M_LINKER);
1024}
1025
1026static const char *
1027symbol_name(elf_file_t ef, Elf_Size r_info)
1028{
1029	const Elf_Sym *ref;
1030
1031	if (ELF_R_SYM(r_info)) {
1032		ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1033		return ef->ddbstrtab + ref->st_name;
1034	} else
1035		return NULL;
1036}
1037
1038static Elf_Addr
1039findbase(elf_file_t ef, int sec)
1040{
1041	int i;
1042	Elf_Addr base = 0;
1043
1044	for (i = 0; i < ef->nprogtab; i++) {
1045		if (sec == ef->progtab[i].sec) {
1046			base = (Elf_Addr)ef->progtab[i].addr;
1047			break;
1048		}
1049	}
1050	return base;
1051}
1052
1053static int
1054relocate_file(elf_file_t ef)
1055{
1056	const Elf_Rel *rellim;
1057	const Elf_Rel *rel;
1058	const Elf_Rela *relalim;
1059	const Elf_Rela *rela;
1060	const char *symname;
1061	const Elf_Sym *sym;
1062	int i;
1063	Elf_Size symidx;
1064	Elf_Addr base;
1065
1066
1067	/* Perform relocations without addend if there are any: */
1068	for (i = 0; i < ef->nreltab; i++) {
1069		rel = ef->reltab[i].rel;
1070		if (rel == NULL) {
1071			link_elf_error(ef->lf.filename, "lost a reltab!");
1072			return (ENOEXEC);
1073		}
1074		rellim = rel + ef->reltab[i].nrel;
1075		base = findbase(ef, ef->reltab[i].sec);
1076		if (base == 0) {
1077			link_elf_error(ef->lf.filename, "lost base for reltab");
1078			return (ENOEXEC);
1079		}
1080		for ( ; rel < rellim; rel++) {
1081			symidx = ELF_R_SYM(rel->r_info);
1082			if (symidx >= ef->ddbsymcnt)
1083				continue;
1084			sym = ef->ddbsymtab + symidx;
1085			/* Local relocs are already done */
1086			if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1087				continue;
1088			if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1089			    elf_obj_lookup)) {
1090				symname = symbol_name(ef, rel->r_info);
1091				printf("link_elf_obj: symbol %s undefined\n",
1092				    symname);
1093				return (ENOENT);
1094			}
1095		}
1096	}
1097
1098	/* Perform relocations with addend if there are any: */
1099	for (i = 0; i < ef->nrelatab; i++) {
1100		rela = ef->relatab[i].rela;
1101		if (rela == NULL) {
1102			link_elf_error(ef->lf.filename, "lost a relatab!");
1103			return (ENOEXEC);
1104		}
1105		relalim = rela + ef->relatab[i].nrela;
1106		base = findbase(ef, ef->relatab[i].sec);
1107		if (base == 0) {
1108			link_elf_error(ef->lf.filename,
1109			    "lost base for relatab");
1110			return (ENOEXEC);
1111		}
1112		for ( ; rela < relalim; rela++) {
1113			symidx = ELF_R_SYM(rela->r_info);
1114			if (symidx >= ef->ddbsymcnt)
1115				continue;
1116			sym = ef->ddbsymtab + symidx;
1117			/* Local relocs are already done */
1118			if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1119				continue;
1120			if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1121			    elf_obj_lookup)) {
1122				symname = symbol_name(ef, rela->r_info);
1123				printf("link_elf_obj: symbol %s undefined\n",
1124				    symname);
1125				return (ENOENT);
1126			}
1127		}
1128	}
1129
1130	/*
1131	 * Only clean SHN_FBSD_CACHED for successful return.  If we
1132	 * modified symbol table for the object but found an
1133	 * unresolved symbol, there is no reason to roll back.
1134	 */
1135	elf_obj_cleanup_globals_cache(ef);
1136
1137	return (0);
1138}
1139
1140static int
1141link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1142{
1143	elf_file_t ef = (elf_file_t) lf;
1144	const Elf_Sym *symp;
1145	const char *strp;
1146	int i;
1147
1148	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1149		strp = ef->ddbstrtab + symp->st_name;
1150		if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1151			*sym = (c_linker_sym_t) symp;
1152			return 0;
1153		}
1154	}
1155	return ENOENT;
1156}
1157
1158static int
1159link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1160    linker_symval_t *symval)
1161{
1162	elf_file_t ef = (elf_file_t) lf;
1163	const Elf_Sym *es = (const Elf_Sym*) sym;
1164
1165	if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1166		symval->name = ef->ddbstrtab + es->st_name;
1167		symval->value = (caddr_t)es->st_value;
1168		symval->size = es->st_size;
1169		return 0;
1170	}
1171	return ENOENT;
1172}
1173
1174static int
1175link_elf_search_symbol(linker_file_t lf, caddr_t value,
1176    c_linker_sym_t *sym, long *diffp)
1177{
1178	elf_file_t ef = (elf_file_t) lf;
1179	u_long off = (uintptr_t) (void *) value;
1180	u_long diff = off;
1181	u_long st_value;
1182	const Elf_Sym *es;
1183	const Elf_Sym *best = NULL;
1184	int i;
1185
1186	for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1187		if (es->st_name == 0)
1188			continue;
1189		st_value = es->st_value;
1190		if (off >= st_value) {
1191			if (off - st_value < diff) {
1192				diff = off - st_value;
1193				best = es;
1194				if (diff == 0)
1195					break;
1196			} else if (off - st_value == diff) {
1197				best = es;
1198			}
1199		}
1200	}
1201	if (best == NULL)
1202		*diffp = off;
1203	else
1204		*diffp = diff;
1205	*sym = (c_linker_sym_t) best;
1206
1207	return 0;
1208}
1209
1210/*
1211 * Look up a linker set on an ELF system.
1212 */
1213static int
1214link_elf_lookup_set(linker_file_t lf, const char *name,
1215    void ***startp, void ***stopp, int *countp)
1216{
1217	elf_file_t ef = (elf_file_t)lf;
1218	void **start, **stop;
1219	int i, count;
1220
1221	/* Relative to section number */
1222	for (i = 0; i < ef->nprogtab; i++) {
1223		if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1224		    strcmp(ef->progtab[i].name + 4, name) == 0) {
1225			start  = (void **)ef->progtab[i].addr;
1226			stop = (void **)((char *)ef->progtab[i].addr +
1227			    ef->progtab[i].size);
1228			count = stop - start;
1229			if (startp)
1230				*startp = start;
1231			if (stopp)
1232				*stopp = stop;
1233			if (countp)
1234				*countp = count;
1235			return (0);
1236		}
1237	}
1238	return (ESRCH);
1239}
1240
1241static int
1242link_elf_each_function_name(linker_file_t file,
1243    int (*callback)(const char *, void *), void *opaque)
1244{
1245	elf_file_t ef = (elf_file_t)file;
1246	const Elf_Sym *symp;
1247	int i, error;
1248
1249	/* Exhaustive search */
1250	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1251		if (symp->st_value != 0 &&
1252		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1253			error = callback(ef->ddbstrtab + symp->st_name, opaque);
1254			if (error)
1255				return (error);
1256		}
1257	}
1258	return (0);
1259}
1260
1261static int
1262link_elf_each_function_nameval(linker_file_t file,
1263    linker_function_nameval_callback_t callback, void *opaque)
1264{
1265	linker_symval_t symval;
1266	elf_file_t ef = (elf_file_t)file;
1267	const Elf_Sym* symp;
1268	int i, error;
1269
1270	/* Exhaustive search */
1271	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1272		if (symp->st_value != 0 &&
1273		    ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1274			error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1275			if (error)
1276				return (error);
1277			error = callback(file, i, &symval, opaque);
1278			if (error)
1279				return (error);
1280		}
1281	}
1282	return (0);
1283}
1284
1285static void
1286elf_obj_cleanup_globals_cache(elf_file_t ef)
1287{
1288	Elf_Sym *sym;
1289	Elf_Size i;
1290
1291	for (i = 0; i < ef->ddbsymcnt; i++) {
1292		sym = ef->ddbsymtab + i;
1293		if (sym->st_shndx == SHN_FBSD_CACHED) {
1294			sym->st_shndx = SHN_UNDEF;
1295			sym->st_value = 0;
1296		}
1297	}
1298}
1299
1300/*
1301 * Symbol lookup function that can be used when the symbol index is known (ie
1302 * in relocations). It uses the symbol index instead of doing a fully fledged
1303 * hash table based lookup when such is valid. For example for local symbols.
1304 * This is not only more efficient, it's also more correct. It's not always
1305 * the case that the symbol can be found through the hash table.
1306 */
1307static int
1308elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1309{
1310	elf_file_t ef = (elf_file_t)lf;
1311	Elf_Sym *sym;
1312	const char *symbol;
1313	Elf_Addr res1;
1314
1315	/* Don't even try to lookup the symbol if the index is bogus. */
1316	if (symidx >= ef->ddbsymcnt) {
1317		*res = 0;
1318		return (EINVAL);
1319	}
1320
1321	sym = ef->ddbsymtab + symidx;
1322
1323	/* Quick answer if there is a definition included. */
1324	if (sym->st_shndx != SHN_UNDEF) {
1325		*res = sym->st_value;
1326		return (0);
1327	}
1328
1329	/* If we get here, then it is undefined and needs a lookup. */
1330	switch (ELF_ST_BIND(sym->st_info)) {
1331	case STB_LOCAL:
1332		/* Local, but undefined? huh? */
1333		*res = 0;
1334		return (EINVAL);
1335
1336	case STB_GLOBAL:
1337	case STB_WEAK:
1338		/* Relative to Data or Function name */
1339		symbol = ef->ddbstrtab + sym->st_name;
1340
1341		/* Force a lookup failure if the symbol name is bogus. */
1342		if (*symbol == 0) {
1343			*res = 0;
1344			return (EINVAL);
1345		}
1346		res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1347
1348		/*
1349		 * Cache global lookups during module relocation. The failure
1350		 * case is particularly expensive for callers, who must scan
1351		 * through the entire globals table doing strcmp(). Cache to
1352		 * avoid doing such work repeatedly.
1353		 *
1354		 * After relocation is complete, undefined globals will be
1355		 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1356		 * above.
1357		 */
1358		if (res1 != 0) {
1359			sym->st_shndx = SHN_FBSD_CACHED;
1360			sym->st_value = res1;
1361			*res = res1;
1362			return (0);
1363		} else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1364			sym->st_value = 0;
1365			*res = 0;
1366			return (0);
1367		}
1368		return (EINVAL);
1369
1370	default:
1371		return (EINVAL);
1372	}
1373}
1374
1375static void
1376link_elf_fix_link_set(elf_file_t ef)
1377{
1378	static const char startn[] = "__start_";
1379	static const char stopn[] = "__stop_";
1380	Elf_Sym *sym;
1381	const char *sym_name, *linkset_name;
1382	Elf_Addr startp, stopp;
1383	Elf_Size symidx;
1384	int start, i;
1385
1386	startp = stopp = 0;
1387	for (symidx = 1 /* zero entry is special */;
1388		symidx < ef->ddbsymcnt; symidx++) {
1389		sym = ef->ddbsymtab + symidx;
1390		if (sym->st_shndx != SHN_UNDEF)
1391			continue;
1392
1393		sym_name = ef->ddbstrtab + sym->st_name;
1394		if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1395			start = 1;
1396			linkset_name = sym_name + sizeof(startn) - 1;
1397		}
1398		else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1399			start = 0;
1400			linkset_name = sym_name + sizeof(stopn) - 1;
1401		}
1402		else
1403			continue;
1404
1405		for (i = 0; i < ef->nprogtab; i++) {
1406			if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1407				startp = (Elf_Addr)ef->progtab[i].addr;
1408				stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1409				break;
1410			}
1411		}
1412		if (i == ef->nprogtab)
1413			continue;
1414
1415		sym->st_value = start ? startp : stopp;
1416		sym->st_shndx = i;
1417	}
1418}
1419
1420static int
1421link_elf_reloc_local(linker_file_t lf)
1422{
1423	elf_file_t ef = (elf_file_t)lf;
1424	const Elf_Rel *rellim;
1425	const Elf_Rel *rel;
1426	const Elf_Rela *relalim;
1427	const Elf_Rela *rela;
1428	const Elf_Sym *sym;
1429	Elf_Addr base;
1430	int i;
1431	Elf_Size symidx;
1432
1433	link_elf_fix_link_set(ef);
1434
1435	/* Perform relocations without addend if there are any: */
1436	for (i = 0; i < ef->nreltab; i++) {
1437		rel = ef->reltab[i].rel;
1438		if (rel == NULL) {
1439			link_elf_error(ef->lf.filename, "lost a reltab");
1440			return (ENOEXEC);
1441		}
1442		rellim = rel + ef->reltab[i].nrel;
1443		base = findbase(ef, ef->reltab[i].sec);
1444		if (base == 0) {
1445			link_elf_error(ef->lf.filename, "lost base for reltab");
1446			return (ENOEXEC);
1447		}
1448		for ( ; rel < rellim; rel++) {
1449			symidx = ELF_R_SYM(rel->r_info);
1450			if (symidx >= ef->ddbsymcnt)
1451				continue;
1452			sym = ef->ddbsymtab + symidx;
1453			/* Only do local relocs */
1454			if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1455				continue;
1456			elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1457			    elf_obj_lookup);
1458		}
1459	}
1460
1461	/* Perform relocations with addend if there are any: */
1462	for (i = 0; i < ef->nrelatab; i++) {
1463		rela = ef->relatab[i].rela;
1464		if (rela == NULL) {
1465			link_elf_error(ef->lf.filename, "lost a relatab!");
1466			return (ENOEXEC);
1467		}
1468		relalim = rela + ef->relatab[i].nrela;
1469		base = findbase(ef, ef->relatab[i].sec);
1470		if (base == 0) {
1471			link_elf_error(ef->lf.filename, "lost base for reltab");
1472			return (ENOEXEC);
1473		}
1474		for ( ; rela < relalim; rela++) {
1475			symidx = ELF_R_SYM(rela->r_info);
1476			if (symidx >= ef->ddbsymcnt)
1477				continue;
1478			sym = ef->ddbsymtab + symidx;
1479			/* Only do local relocs */
1480			if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1481				continue;
1482			elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1483			    elf_obj_lookup);
1484		}
1485	}
1486	return (0);
1487}
1488
1489static long
1490link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1491{
1492    elf_file_t ef = (elf_file_t)lf;
1493
1494    *symtab = ef->ddbsymtab;
1495
1496    if (*symtab == NULL)
1497        return (0);
1498
1499    return (ef->ddbsymcnt);
1500}
1501
1502static long
1503link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1504{
1505    elf_file_t ef = (elf_file_t)lf;
1506
1507    *strtab = ef->ddbstrtab;
1508
1509    if (*strtab == NULL)
1510        return (0);
1511
1512    return (ef->ddbstrcnt);
1513}
1514