FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf.c
1 /*-
2 * Copyright (c) 1998-2000 Doug Rabson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/8.1/sys/kern/link_elf.c 199583 2009-11-20 15:27:52Z jhb $");
29
30 #include "opt_ddb.h"
31 #include "opt_gdb.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #ifdef GPROF
36 #include <sys/gmon.h>
37 #endif
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/mount.h>
43 #include <sys/pcpu.h>
44 #include <sys/proc.h>
45 #include <sys/namei.h>
46 #include <sys/fcntl.h>
47 #include <sys/vnode.h>
48 #include <sys/linker.h>
49
50 #include <machine/elf.h>
51
52 #include <net/vnet.h>
53
54 #include <security/mac/mac_framework.h>
55
56 #include <vm/vm.h>
57 #include <vm/vm_param.h>
58 #ifdef SPARSE_MAPPING
59 #include <vm/vm_object.h>
60 #include <vm/vm_kern.h>
61 #include <vm/vm_extern.h>
62 #endif
63 #include <vm/pmap.h>
64 #include <vm/vm_map.h>
65
66 #include <sys/link_elf.h>
67
68 #ifdef DDB_CTF
69 #include <net/zlib.h>
70 #endif
71
72 #include "linker_if.h"
73
74 #define MAXSEGS 4
75
76 typedef struct elf_file {
77 struct linker_file lf; /* Common fields */
78 int preloaded; /* Was file pre-loaded */
79 caddr_t address; /* Relocation address */
80 #ifdef SPARSE_MAPPING
81 vm_object_t object; /* VM object to hold file pages */
82 #endif
83 Elf_Dyn* dynamic; /* Symbol table etc. */
84 Elf_Hashelt nbuckets; /* DT_HASH info */
85 Elf_Hashelt nchains;
86 const Elf_Hashelt* buckets;
87 const Elf_Hashelt* chains;
88 caddr_t hash;
89 caddr_t strtab; /* DT_STRTAB */
90 int strsz; /* DT_STRSZ */
91 const Elf_Sym* symtab; /* DT_SYMTAB */
92 Elf_Addr* got; /* DT_PLTGOT */
93 const Elf_Rel* pltrel; /* DT_JMPREL */
94 int pltrelsize; /* DT_PLTRELSZ */
95 const Elf_Rela* pltrela; /* DT_JMPREL */
96 int pltrelasize; /* DT_PLTRELSZ */
97 const Elf_Rel* rel; /* DT_REL */
98 int relsize; /* DT_RELSZ */
99 const Elf_Rela* rela; /* DT_RELA */
100 int relasize; /* DT_RELASZ */
101 caddr_t modptr;
102 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
103 long ddbsymcnt; /* Number of symbols */
104 caddr_t ddbstrtab; /* String table */
105 long ddbstrcnt; /* number of bytes in string table */
106 caddr_t symbase; /* malloc'ed symbold base */
107 caddr_t strbase; /* malloc'ed string base */
108 caddr_t ctftab; /* CTF table */
109 long ctfcnt; /* number of bytes in CTF table */
110 caddr_t ctfoff; /* CTF offset table */
111 caddr_t typoff; /* Type offset table */
112 long typlen; /* Number of type entries. */
113 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
114 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
115 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
116 #ifdef VIMAGE
117 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
118 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
119 Elf_Addr vnet_base; /* Relocated vnet set address. */
120 #endif
121 #ifdef GDB
122 struct link_map gdb; /* hooks for gdb */
123 #endif
124 } *elf_file_t;
125
126 #include <kern/kern_ctf.c>
127
128 static int link_elf_link_common_finish(linker_file_t);
129 static int link_elf_link_preload(linker_class_t cls,
130 const char*, linker_file_t*);
131 static int link_elf_link_preload_finish(linker_file_t);
132 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*);
133 static int link_elf_lookup_symbol(linker_file_t, const char*,
134 c_linker_sym_t*);
135 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
136 static int link_elf_search_symbol(linker_file_t, caddr_t value,
137 c_linker_sym_t* sym, long* diffp);
138
139 static void link_elf_unload_file(linker_file_t);
140 static void link_elf_unload_preload(linker_file_t);
141 static int link_elf_lookup_set(linker_file_t, const char *,
142 void ***, void ***, int *);
143 static int link_elf_each_function_name(linker_file_t,
144 int (*)(const char *, void *),
145 void *);
146 static int link_elf_each_function_nameval(linker_file_t,
147 linker_function_nameval_callback_t,
148 void *);
149 static void link_elf_reloc_local(linker_file_t);
150 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
151 static long link_elf_strtab_get(linker_file_t, caddr_t *);
152 static Elf_Addr elf_lookup(linker_file_t lf, Elf_Size symidx, int deps);
153
154 static kobj_method_t link_elf_methods[] = {
155 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
156 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
157 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
158 KOBJMETHOD(linker_unload, link_elf_unload_file),
159 KOBJMETHOD(linker_load_file, link_elf_load_file),
160 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
161 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
162 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
163 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
164 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
165 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
166 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
167 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
168 { 0, 0 }
169 };
170
171 static struct linker_class link_elf_class = {
172 #if ELF_TARG_CLASS == ELFCLASS32
173 "elf32",
174 #else
175 "elf64",
176 #endif
177 link_elf_methods, sizeof(struct elf_file)
178 };
179
180 static int parse_dynamic(elf_file_t ef);
181 static int relocate_file(elf_file_t ef);
182 static int link_elf_preload_parse_symbols(elf_file_t ef);
183
184 #ifdef GDB
185 static void r_debug_state(struct r_debug *dummy_one,
186 struct link_map *dummy_two);
187
188 /*
189 * A list of loaded modules for GDB to use for loading symbols.
190 */
191 struct r_debug r_debug;
192
193 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL);
194
195 /*
196 * Function for the debugger to set a breakpoint on to gain control.
197 */
198 static void
199 r_debug_state(struct r_debug *dummy_one __unused,
200 struct link_map *dummy_two __unused)
201 {
202 }
203
204 static void
205 link_elf_add_gdb(struct link_map *l)
206 {
207 struct link_map *prev;
208
209 l->l_next = NULL;
210
211 if (r_debug.r_map == NULL) {
212 /* Add first. */
213 l->l_prev = NULL;
214 r_debug.r_map = l;
215 } else {
216 /* Append to list. */
217 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
218 ;
219 l->l_prev = prev;
220 prev->l_next = l;
221 }
222 }
223
224 static void
225 link_elf_delete_gdb(struct link_map *l)
226 {
227 if (l->l_prev == NULL) {
228 /* Remove first. */
229 if ((r_debug.r_map = l->l_next) != NULL)
230 l->l_next->l_prev = NULL;
231 } else {
232 /* Remove any but first. */
233 if ((l->l_prev->l_next = l->l_next) != NULL)
234 l->l_next->l_prev = l->l_prev;
235 }
236 }
237 #endif /* GDB */
238
239 #ifdef __ia64__
240 Elf_Addr link_elf_get_gp(linker_file_t);
241 #endif
242
243 /*
244 * The kernel symbol table starts here.
245 */
246 extern struct _dynamic _DYNAMIC;
247
248 static void
249 link_elf_error(const char *filename, const char *s)
250 {
251 if (filename == NULL)
252 printf("kldload: %s\n", s);
253 else
254 printf("kldload: %s: %s\n", filename, s);
255 }
256
257 /*
258 * Actions performed after linking/loading both the preloaded kernel and any
259 * modules; whether preloaded or dynamicly loaded.
260 */
261 static int
262 link_elf_link_common_finish(linker_file_t lf)
263 {
264 #ifdef GDB
265 elf_file_t ef = (elf_file_t)lf;
266 char *newfilename;
267 #endif
268 int error;
269
270 /* Notify MD code that a module is being loaded. */
271 error = elf_cpu_load_file(lf);
272 if (error)
273 return (error);
274
275 #ifdef GDB
276 GDB_STATE(RT_ADD);
277 ef->gdb.l_addr = lf->address;
278 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
279 strcpy(newfilename, lf->filename);
280 ef->gdb.l_name = newfilename;
281 ef->gdb.l_ld = ef->dynamic;
282 link_elf_add_gdb(&ef->gdb);
283 GDB_STATE(RT_CONSISTENT);
284 #endif
285
286 return (0);
287 }
288
289 static void
290 link_elf_init(void* arg)
291 {
292 Elf_Dyn *dp;
293 caddr_t modptr, baseptr, sizeptr;
294 elf_file_t ef;
295 char *modname;
296
297 linker_add_class(&link_elf_class);
298
299 dp = (Elf_Dyn*) &_DYNAMIC;
300 modname = NULL;
301 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
302 if (modptr == NULL)
303 modptr = preload_search_by_type("elf kernel");
304 if (modptr)
305 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
306 if (modname == NULL)
307 modname = "kernel";
308 linker_kernel_file = linker_make_file(modname, &link_elf_class);
309 if (linker_kernel_file == NULL)
310 panic("link_elf_init: Can't create linker structures for kernel");
311
312 ef = (elf_file_t) linker_kernel_file;
313 ef->preloaded = 1;
314 ef->address = 0;
315 #ifdef SPARSE_MAPPING
316 ef->object = 0;
317 #endif
318 ef->dynamic = dp;
319
320 if (dp)
321 parse_dynamic(ef);
322 linker_kernel_file->address = (caddr_t) KERNBASE;
323 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
324
325 if (modptr) {
326 ef->modptr = modptr;
327 baseptr = preload_search_info(modptr, MODINFO_ADDR);
328 if (baseptr)
329 linker_kernel_file->address = *(caddr_t *)baseptr;
330 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
331 if (sizeptr)
332 linker_kernel_file->size = *(size_t *)sizeptr;
333 }
334 (void)link_elf_preload_parse_symbols(ef);
335
336 #ifdef GDB
337 r_debug.r_map = NULL;
338 r_debug.r_brk = r_debug_state;
339 r_debug.r_state = RT_CONSISTENT;
340 #endif
341
342 (void)link_elf_link_common_finish(linker_kernel_file);
343 linker_kernel_file->flags |= LINKER_FILE_LINKED;
344 }
345
346 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
347
348 static int
349 link_elf_preload_parse_symbols(elf_file_t ef)
350 {
351 caddr_t pointer;
352 caddr_t ssym, esym, base;
353 caddr_t strtab;
354 int strcnt;
355 Elf_Sym* symtab;
356 int symcnt;
357
358 if (ef->modptr == NULL)
359 return 0;
360 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
361 if (pointer == NULL)
362 return 0;
363 ssym = *(caddr_t *)pointer;
364 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
365 if (pointer == NULL)
366 return 0;
367 esym = *(caddr_t *)pointer;
368
369 base = ssym;
370
371 symcnt = *(long *)base;
372 base += sizeof(long);
373 symtab = (Elf_Sym *)base;
374 base += roundup(symcnt, sizeof(long));
375
376 if (base > esym || base < ssym) {
377 printf("Symbols are corrupt!\n");
378 return EINVAL;
379 }
380
381 strcnt = *(long *)base;
382 base += sizeof(long);
383 strtab = base;
384 base += roundup(strcnt, sizeof(long));
385
386 if (base > esym || base < ssym) {
387 printf("Symbols are corrupt!\n");
388 return EINVAL;
389 }
390
391 ef->ddbsymtab = symtab;
392 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
393 ef->ddbstrtab = strtab;
394 ef->ddbstrcnt = strcnt;
395
396 return 0;
397 }
398
399 static int
400 parse_dynamic(elf_file_t ef)
401 {
402 Elf_Dyn *dp;
403 int plttype = DT_REL;
404
405 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
406 switch (dp->d_tag) {
407 case DT_HASH:
408 {
409 /* From src/libexec/rtld-elf/rtld.c */
410 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
411 (ef->address + dp->d_un.d_ptr);
412 ef->nbuckets = hashtab[0];
413 ef->nchains = hashtab[1];
414 ef->buckets = hashtab + 2;
415 ef->chains = ef->buckets + ef->nbuckets;
416 break;
417 }
418 case DT_STRTAB:
419 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
420 break;
421 case DT_STRSZ:
422 ef->strsz = dp->d_un.d_val;
423 break;
424 case DT_SYMTAB:
425 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
426 break;
427 case DT_SYMENT:
428 if (dp->d_un.d_val != sizeof(Elf_Sym))
429 return ENOEXEC;
430 break;
431 case DT_PLTGOT:
432 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
433 break;
434 case DT_REL:
435 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
436 break;
437 case DT_RELSZ:
438 ef->relsize = dp->d_un.d_val;
439 break;
440 case DT_RELENT:
441 if (dp->d_un.d_val != sizeof(Elf_Rel))
442 return ENOEXEC;
443 break;
444 case DT_JMPREL:
445 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
446 break;
447 case DT_PLTRELSZ:
448 ef->pltrelsize = dp->d_un.d_val;
449 break;
450 case DT_RELA:
451 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
452 break;
453 case DT_RELASZ:
454 ef->relasize = dp->d_un.d_val;
455 break;
456 case DT_RELAENT:
457 if (dp->d_un.d_val != sizeof(Elf_Rela))
458 return ENOEXEC;
459 break;
460 case DT_PLTREL:
461 plttype = dp->d_un.d_val;
462 if (plttype != DT_REL && plttype != DT_RELA)
463 return ENOEXEC;
464 break;
465 #ifdef GDB
466 case DT_DEBUG:
467 dp->d_un.d_ptr = (Elf_Addr) &r_debug;
468 break;
469 #endif
470 }
471 }
472
473 if (plttype == DT_RELA) {
474 ef->pltrela = (const Elf_Rela *) ef->pltrel;
475 ef->pltrel = NULL;
476 ef->pltrelasize = ef->pltrelsize;
477 ef->pltrelsize = 0;
478 }
479
480 ef->ddbsymtab = ef->symtab;
481 ef->ddbsymcnt = ef->nchains;
482 ef->ddbstrtab = ef->strtab;
483 ef->ddbstrcnt = ef->strsz;
484
485 return 0;
486 }
487
488 static int
489 parse_dpcpu(elf_file_t ef)
490 {
491 int count;
492 int error;
493
494 ef->pcpu_start = 0;
495 ef->pcpu_stop = 0;
496 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
497 (void ***)&ef->pcpu_stop, &count);
498 /* Error just means there is no pcpu set to relocate. */
499 if (error)
500 return (0);
501 count *= sizeof(void *);
502 /*
503 * Allocate space in the primary pcpu area. Copy in our initialization
504 * from the data section and then initialize all per-cpu storage from
505 * that.
506 */
507 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
508 if (ef->pcpu_base == (Elf_Addr)NULL)
509 return (ENOSPC);
510 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
511 dpcpu_copy((void *)ef->pcpu_base, count);
512
513 return (0);
514 }
515
516 #ifdef VIMAGE
517 static int
518 parse_vnet(elf_file_t ef)
519 {
520 int count;
521 int error;
522
523 ef->vnet_start = 0;
524 ef->vnet_stop = 0;
525 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
526 (void ***)&ef->vnet_stop, &count);
527 /* Error just means there is no vnet data set to relocate. */
528 if (error)
529 return (0);
530 count *= sizeof(void *);
531 /*
532 * Allocate space in the primary vnet area. Copy in our initialization
533 * from the data section and then initialize all per-vnet storage from
534 * that.
535 */
536 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
537 if (ef->vnet_base == (Elf_Addr)NULL)
538 return (ENOSPC);
539 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
540 vnet_data_copy((void *)ef->vnet_base, count);
541
542 return (0);
543 }
544 #endif
545
546 static int
547 link_elf_link_preload(linker_class_t cls,
548 const char* filename, linker_file_t *result)
549 {
550 caddr_t modptr, baseptr, sizeptr, dynptr;
551 char *type;
552 elf_file_t ef;
553 linker_file_t lf;
554 int error;
555 vm_offset_t dp;
556
557 /* Look to see if we have the file preloaded */
558 modptr = preload_search_by_name(filename);
559 if (modptr == NULL)
560 return ENOENT;
561
562 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
563 baseptr = preload_search_info(modptr, MODINFO_ADDR);
564 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
565 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
566 if (type == NULL ||
567 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
568 strcmp(type, "elf module") != 0))
569 return (EFTYPE);
570 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
571 return (EINVAL);
572
573 lf = linker_make_file(filename, &link_elf_class);
574 if (lf == NULL) {
575 return ENOMEM;
576 }
577
578 ef = (elf_file_t) lf;
579 ef->preloaded = 1;
580 ef->modptr = modptr;
581 ef->address = *(caddr_t *)baseptr;
582 #ifdef SPARSE_MAPPING
583 ef->object = 0;
584 #endif
585 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
586 ef->dynamic = (Elf_Dyn *)dp;
587 lf->address = ef->address;
588 lf->size = *(size_t *)sizeptr;
589
590 error = parse_dynamic(ef);
591 if (error == 0)
592 error = parse_dpcpu(ef);
593 #ifdef VIMAGE
594 if (error == 0)
595 error = parse_vnet(ef);
596 #endif
597 if (error) {
598 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
599 return error;
600 }
601 link_elf_reloc_local(lf);
602 *result = lf;
603 return (0);
604 }
605
606 static int
607 link_elf_link_preload_finish(linker_file_t lf)
608 {
609 elf_file_t ef;
610 int error;
611
612 ef = (elf_file_t) lf;
613 #if 0 /* this will be more trouble than it's worth for now */
614 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
615 if (dp->d_tag != DT_NEEDED)
616 continue;
617 modname = ef->strtab + dp->d_un.d_val;
618 error = linker_load_module(modname, lf);
619 if (error)
620 goto out;
621 }
622 #endif
623 error = relocate_file(ef);
624 if (error)
625 return error;
626 (void)link_elf_preload_parse_symbols(ef);
627
628 return (link_elf_link_common_finish(lf));
629 }
630
631 static int
632 link_elf_load_file(linker_class_t cls, const char* filename,
633 linker_file_t* result)
634 {
635 struct nameidata nd;
636 struct thread* td = curthread; /* XXX */
637 Elf_Ehdr *hdr;
638 caddr_t firstpage;
639 int nbytes, i;
640 Elf_Phdr *phdr;
641 Elf_Phdr *phlimit;
642 Elf_Phdr *segs[MAXSEGS];
643 int nsegs;
644 Elf_Phdr *phdyn;
645 Elf_Phdr *phphdr;
646 caddr_t mapbase;
647 size_t mapsize;
648 Elf_Off base_offset;
649 Elf_Addr base_vaddr;
650 Elf_Addr base_vlimit;
651 int error = 0;
652 int resid, flags;
653 elf_file_t ef;
654 linker_file_t lf;
655 Elf_Shdr *shdr;
656 int symtabindex;
657 int symstrindex;
658 int symcnt;
659 int strcnt;
660 int vfslocked;
661
662 shdr = NULL;
663 lf = NULL;
664
665 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
666 flags = FREAD;
667 error = vn_open(&nd, &flags, 0, NULL);
668 if (error)
669 return error;
670 vfslocked = NDHASGIANT(&nd);
671 NDFREE(&nd, NDF_ONLY_PNBUF);
672 if (nd.ni_vp->v_type != VREG) {
673 error = ENOEXEC;
674 firstpage = NULL;
675 goto out;
676 }
677 #ifdef MAC
678 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
679 if (error) {
680 firstpage = NULL;
681 goto out;
682 }
683 #endif
684
685 /*
686 * Read the elf header from the file.
687 */
688 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
689 if (firstpage == NULL) {
690 error = ENOMEM;
691 goto out;
692 }
693 hdr = (Elf_Ehdr *)firstpage;
694 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
695 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
696 &resid, td);
697 nbytes = PAGE_SIZE - resid;
698 if (error)
699 goto out;
700
701 if (!IS_ELF(*hdr)) {
702 error = ENOEXEC;
703 goto out;
704 }
705
706 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
707 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
708 link_elf_error(filename, "Unsupported file layout");
709 error = ENOEXEC;
710 goto out;
711 }
712 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
713 || hdr->e_version != EV_CURRENT) {
714 link_elf_error(filename, "Unsupported file version");
715 error = ENOEXEC;
716 goto out;
717 }
718 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
719 error = ENOSYS;
720 goto out;
721 }
722 if (hdr->e_machine != ELF_TARG_MACH) {
723 link_elf_error(filename, "Unsupported machine");
724 error = ENOEXEC;
725 goto out;
726 }
727
728 /*
729 * We rely on the program header being in the first page. This is
730 * not strictly required by the ABI specification, but it seems to
731 * always true in practice. And, it simplifies things considerably.
732 */
733 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
734 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
735 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
736 link_elf_error(filename, "Unreadable program headers");
737
738 /*
739 * Scan the program header entries, and save key information.
740 *
741 * We rely on there being exactly two load segments, text and data,
742 * in that order.
743 */
744 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
745 phlimit = phdr + hdr->e_phnum;
746 nsegs = 0;
747 phdyn = NULL;
748 phphdr = NULL;
749 while (phdr < phlimit) {
750 switch (phdr->p_type) {
751
752 case PT_LOAD:
753 if (nsegs == MAXSEGS) {
754 link_elf_error(filename, "Too many sections");
755 error = ENOEXEC;
756 goto out;
757 }
758 /*
759 * XXX: We just trust they come in right order ??
760 */
761 segs[nsegs] = phdr;
762 ++nsegs;
763 break;
764
765 case PT_PHDR:
766 phphdr = phdr;
767 break;
768
769 case PT_DYNAMIC:
770 phdyn = phdr;
771 break;
772
773 case PT_INTERP:
774 error = ENOSYS;
775 goto out;
776 }
777
778 ++phdr;
779 }
780 if (phdyn == NULL) {
781 link_elf_error(filename, "Object is not dynamically-linked");
782 error = ENOEXEC;
783 goto out;
784 }
785 if (nsegs == 0) {
786 link_elf_error(filename, "No sections");
787 error = ENOEXEC;
788 goto out;
789 }
790
791 /*
792 * Allocate the entire address space of the object, to stake out our
793 * contiguous region, and to establish the base address for relocation.
794 */
795 base_offset = trunc_page(segs[0]->p_offset);
796 base_vaddr = trunc_page(segs[0]->p_vaddr);
797 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
798 segs[nsegs - 1]->p_memsz);
799 mapsize = base_vlimit - base_vaddr;
800
801 lf = linker_make_file(filename, &link_elf_class);
802 if (!lf) {
803 error = ENOMEM;
804 goto out;
805 }
806
807 ef = (elf_file_t) lf;
808 #ifdef SPARSE_MAPPING
809 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
810 if (ef->object == NULL) {
811 error = ENOMEM;
812 goto out;
813 }
814 ef->address = (caddr_t) vm_map_min(kernel_map);
815 error = vm_map_find(kernel_map, ef->object, 0,
816 (vm_offset_t *) &ef->address,
817 mapsize, 1,
818 VM_PROT_ALL, VM_PROT_ALL, 0);
819 if (error) {
820 vm_object_deallocate(ef->object);
821 ef->object = 0;
822 goto out;
823 }
824 #else
825 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
826 if (!ef->address) {
827 error = ENOMEM;
828 goto out;
829 }
830 #endif
831 mapbase = ef->address;
832
833 /*
834 * Read the text and data sections and zero the bss.
835 */
836 for (i = 0; i < nsegs; i++) {
837 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
838 error = vn_rdwr(UIO_READ, nd.ni_vp,
839 segbase, segs[i]->p_filesz, segs[i]->p_offset,
840 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
841 &resid, td);
842 if (error) {
843 goto out;
844 }
845 bzero(segbase + segs[i]->p_filesz,
846 segs[i]->p_memsz - segs[i]->p_filesz);
847
848 #ifdef SPARSE_MAPPING
849 /*
850 * Wire down the pages
851 */
852 error = vm_map_wire(kernel_map,
853 (vm_offset_t) segbase,
854 (vm_offset_t) segbase + segs[i]->p_memsz,
855 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
856 if (error != KERN_SUCCESS) {
857 error = ENOMEM;
858 goto out;
859 }
860 #endif
861 }
862
863 #ifdef GPROF
864 /* Update profiling information with the new text segment. */
865 mtx_lock(&Giant);
866 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
867 segs[0]->p_memsz));
868 mtx_unlock(&Giant);
869 #endif
870
871 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
872
873 lf->address = ef->address;
874 lf->size = mapsize;
875
876 error = parse_dynamic(ef);
877 if (error)
878 goto out;
879 error = parse_dpcpu(ef);
880 if (error)
881 goto out;
882 #ifdef VIMAGE
883 error = parse_vnet(ef);
884 if (error)
885 goto out;
886 #endif
887 link_elf_reloc_local(lf);
888
889 VOP_UNLOCK(nd.ni_vp, 0);
890 error = linker_load_dependencies(lf);
891 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
892 if (error)
893 goto out;
894 #if 0 /* this will be more trouble than it's worth for now */
895 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
896 if (dp->d_tag != DT_NEEDED)
897 continue;
898 modname = ef->strtab + dp->d_un.d_val;
899 error = linker_load_module(modname, lf);
900 if (error)
901 goto out;
902 }
903 #endif
904 error = relocate_file(ef);
905 if (error)
906 goto out;
907
908 /* Try and load the symbol table if it's present. (you can strip it!) */
909 nbytes = hdr->e_shnum * hdr->e_shentsize;
910 if (nbytes == 0 || hdr->e_shoff == 0)
911 goto nosyms;
912 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
913 if (shdr == NULL) {
914 error = ENOMEM;
915 goto out;
916 }
917 error = vn_rdwr(UIO_READ, nd.ni_vp,
918 (caddr_t)shdr, nbytes, hdr->e_shoff,
919 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
920 &resid, td);
921 if (error)
922 goto out;
923 symtabindex = -1;
924 symstrindex = -1;
925 for (i = 0; i < hdr->e_shnum; i++) {
926 if (shdr[i].sh_type == SHT_SYMTAB) {
927 symtabindex = i;
928 symstrindex = shdr[i].sh_link;
929 }
930 }
931 if (symtabindex < 0 || symstrindex < 0)
932 goto nosyms;
933
934 symcnt = shdr[symtabindex].sh_size;
935 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
936 strcnt = shdr[symstrindex].sh_size;
937 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
938
939 if (ef->symbase == NULL || ef->strbase == NULL) {
940 error = ENOMEM;
941 goto out;
942 }
943 error = vn_rdwr(UIO_READ, nd.ni_vp,
944 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
945 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
946 &resid, td);
947 if (error)
948 goto out;
949 error = vn_rdwr(UIO_READ, nd.ni_vp,
950 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
951 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
952 &resid, td);
953 if (error)
954 goto out;
955
956 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
957 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
958 ef->ddbstrcnt = strcnt;
959 ef->ddbstrtab = ef->strbase;
960
961 error = link_elf_link_common_finish(lf);
962 if (error)
963 goto out;
964
965 nosyms:
966
967 *result = lf;
968
969 out:
970 if (error && lf)
971 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
972 if (shdr)
973 free(shdr, M_LINKER);
974 if (firstpage)
975 free(firstpage, M_LINKER);
976 VOP_UNLOCK(nd.ni_vp, 0);
977 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
978 VFS_UNLOCK_GIANT(vfslocked);
979
980 return error;
981 }
982
983 Elf_Addr
984 elf_relocaddr(linker_file_t lf, Elf_Addr x)
985 {
986 elf_file_t ef;
987
988 ef = (elf_file_t)lf;
989 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
990 return ((x - ef->pcpu_start) + ef->pcpu_base);
991 #ifdef VIMAGE
992 if (x >= ef->vnet_start && x < ef->vnet_stop)
993 return ((x - ef->vnet_start) + ef->vnet_base);
994 #endif
995 return (x);
996 }
997
998
999 static void
1000 link_elf_unload_file(linker_file_t file)
1001 {
1002 elf_file_t ef = (elf_file_t) file;
1003
1004 if (ef->pcpu_base) {
1005 dpcpu_free((void *)ef->pcpu_base, ef->pcpu_stop - ef->pcpu_start);
1006 }
1007 #ifdef VIMAGE
1008 if (ef->vnet_base) {
1009 vnet_data_free((void *)ef->vnet_base, ef->vnet_stop - ef->vnet_start);
1010 }
1011 #endif
1012 #ifdef GDB
1013 if (ef->gdb.l_ld) {
1014 GDB_STATE(RT_DELETE);
1015 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1016 link_elf_delete_gdb(&ef->gdb);
1017 GDB_STATE(RT_CONSISTENT);
1018 }
1019 #endif
1020
1021 /* Notify MD code that a module is being unloaded. */
1022 elf_cpu_unload_file(file);
1023
1024 if (ef->preloaded) {
1025 link_elf_unload_preload(file);
1026 return;
1027 }
1028
1029 #ifdef SPARSE_MAPPING
1030 if (ef->object) {
1031 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1032 (vm_offset_t) ef->address
1033 + (ef->object->size << PAGE_SHIFT));
1034 }
1035 #else
1036 if (ef->address)
1037 free(ef->address, M_LINKER);
1038 #endif
1039 if (ef->symbase)
1040 free(ef->symbase, M_LINKER);
1041 if (ef->strbase)
1042 free(ef->strbase, M_LINKER);
1043 if (ef->ctftab)
1044 free(ef->ctftab, M_LINKER);
1045 if (ef->ctfoff)
1046 free(ef->ctfoff, M_LINKER);
1047 if (ef->typoff)
1048 free(ef->typoff, M_LINKER);
1049 }
1050
1051 static void
1052 link_elf_unload_preload(linker_file_t file)
1053 {
1054 if (file->filename)
1055 preload_delete_name(file->filename);
1056 }
1057
1058 static const char *
1059 symbol_name(elf_file_t ef, Elf_Size r_info)
1060 {
1061 const Elf_Sym *ref;
1062
1063 if (ELF_R_SYM(r_info)) {
1064 ref = ef->symtab + ELF_R_SYM(r_info);
1065 return ef->strtab + ref->st_name;
1066 } else
1067 return NULL;
1068 }
1069
1070 static int
1071 relocate_file(elf_file_t ef)
1072 {
1073 const Elf_Rel *rellim;
1074 const Elf_Rel *rel;
1075 const Elf_Rela *relalim;
1076 const Elf_Rela *rela;
1077 const char *symname;
1078
1079 /* Perform relocations without addend if there are any: */
1080 rel = ef->rel;
1081 if (rel) {
1082 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1083 while (rel < rellim) {
1084 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1085 elf_lookup)) {
1086 symname = symbol_name(ef, rel->r_info);
1087 printf("link_elf: symbol %s undefined\n", symname);
1088 return ENOENT;
1089 }
1090 rel++;
1091 }
1092 }
1093
1094 /* Perform relocations with addend if there are any: */
1095 rela = ef->rela;
1096 if (rela) {
1097 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1098 while (rela < relalim) {
1099 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1100 elf_lookup)) {
1101 symname = symbol_name(ef, rela->r_info);
1102 printf("link_elf: symbol %s undefined\n", symname);
1103 return ENOENT;
1104 }
1105 rela++;
1106 }
1107 }
1108
1109 /* Perform PLT relocations without addend if there are any: */
1110 rel = ef->pltrel;
1111 if (rel) {
1112 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
1113 while (rel < rellim) {
1114 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1115 elf_lookup)) {
1116 symname = symbol_name(ef, rel->r_info);
1117 printf("link_elf: symbol %s undefined\n", symname);
1118 return ENOENT;
1119 }
1120 rel++;
1121 }
1122 }
1123
1124 /* Perform relocations with addend if there are any: */
1125 rela = ef->pltrela;
1126 if (rela) {
1127 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
1128 while (rela < relalim) {
1129 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1130 elf_lookup)) {
1131 symname = symbol_name(ef, rela->r_info);
1132 printf("link_elf: symbol %s undefined\n", symname);
1133 return ENOENT;
1134 }
1135 rela++;
1136 }
1137 }
1138
1139 return 0;
1140 }
1141
1142 /*
1143 * Hash function for symbol table lookup. Don't even think about changing
1144 * this. It is specified by the System V ABI.
1145 */
1146 static unsigned long
1147 elf_hash(const char *name)
1148 {
1149 const unsigned char *p = (const unsigned char *) name;
1150 unsigned long h = 0;
1151 unsigned long g;
1152
1153 while (*p != '\0') {
1154 h = (h << 4) + *p++;
1155 if ((g = h & 0xf0000000) != 0)
1156 h ^= g >> 24;
1157 h &= ~g;
1158 }
1159 return h;
1160 }
1161
1162 static int
1163 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1164 {
1165 elf_file_t ef = (elf_file_t) lf;
1166 unsigned long symnum;
1167 const Elf_Sym* symp;
1168 const char *strp;
1169 unsigned long hash;
1170 int i;
1171
1172 /* If we don't have a hash, bail. */
1173 if (ef->buckets == NULL || ef->nbuckets == 0) {
1174 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1175 return ENOENT;
1176 }
1177
1178 /* First, search hashed global symbols */
1179 hash = elf_hash(name);
1180 symnum = ef->buckets[hash % ef->nbuckets];
1181
1182 while (symnum != STN_UNDEF) {
1183 if (symnum >= ef->nchains) {
1184 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1185 return ENOENT;
1186 }
1187
1188 symp = ef->symtab + symnum;
1189 if (symp->st_name == 0) {
1190 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1191 return ENOENT;
1192 }
1193
1194 strp = ef->strtab + symp->st_name;
1195
1196 if (strcmp(name, strp) == 0) {
1197 if (symp->st_shndx != SHN_UNDEF ||
1198 (symp->st_value != 0 &&
1199 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1200 *sym = (c_linker_sym_t) symp;
1201 return 0;
1202 } else
1203 return ENOENT;
1204 }
1205
1206 symnum = ef->chains[symnum];
1207 }
1208
1209 /* If we have not found it, look at the full table (if loaded) */
1210 if (ef->symtab == ef->ddbsymtab)
1211 return ENOENT;
1212
1213 /* Exhaustive search */
1214 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1215 strp = ef->ddbstrtab + symp->st_name;
1216 if (strcmp(name, strp) == 0) {
1217 if (symp->st_shndx != SHN_UNDEF ||
1218 (symp->st_value != 0 &&
1219 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1220 *sym = (c_linker_sym_t) symp;
1221 return 0;
1222 } else
1223 return ENOENT;
1224 }
1225 }
1226
1227 return ENOENT;
1228 }
1229
1230 static int
1231 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1232 {
1233 elf_file_t ef = (elf_file_t) lf;
1234 const Elf_Sym* es = (const Elf_Sym*) sym;
1235
1236 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1237 symval->name = ef->strtab + es->st_name;
1238 symval->value = (caddr_t) ef->address + es->st_value;
1239 symval->size = es->st_size;
1240 return 0;
1241 }
1242 if (ef->symtab == ef->ddbsymtab)
1243 return ENOENT;
1244 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1245 symval->name = ef->ddbstrtab + es->st_name;
1246 symval->value = (caddr_t) ef->address + es->st_value;
1247 symval->size = es->st_size;
1248 return 0;
1249 }
1250 return ENOENT;
1251 }
1252
1253 static int
1254 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1255 c_linker_sym_t* sym, long* diffp)
1256 {
1257 elf_file_t ef = (elf_file_t) lf;
1258 u_long off = (uintptr_t) (void *) value;
1259 u_long diff = off;
1260 u_long st_value;
1261 const Elf_Sym* es;
1262 const Elf_Sym* best = 0;
1263 int i;
1264
1265 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1266 if (es->st_name == 0)
1267 continue;
1268 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1269 if (off >= st_value) {
1270 if (off - st_value < diff) {
1271 diff = off - st_value;
1272 best = es;
1273 if (diff == 0)
1274 break;
1275 } else if (off - st_value == diff) {
1276 best = es;
1277 }
1278 }
1279 }
1280 if (best == 0)
1281 *diffp = off;
1282 else
1283 *diffp = diff;
1284 *sym = (c_linker_sym_t) best;
1285
1286 return 0;
1287 }
1288
1289 /*
1290 * Look up a linker set on an ELF system.
1291 */
1292 static int
1293 link_elf_lookup_set(linker_file_t lf, const char *name,
1294 void ***startp, void ***stopp, int *countp)
1295 {
1296 c_linker_sym_t sym;
1297 linker_symval_t symval;
1298 char *setsym;
1299 void **start, **stop;
1300 int len, error = 0, count;
1301
1302 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1303 setsym = malloc(len, M_LINKER, M_WAITOK);
1304 if (setsym == NULL)
1305 return ENOMEM;
1306
1307 /* get address of first entry */
1308 snprintf(setsym, len, "%s%s", "__start_set_", name);
1309 error = link_elf_lookup_symbol(lf, setsym, &sym);
1310 if (error)
1311 goto out;
1312 link_elf_symbol_values(lf, sym, &symval);
1313 if (symval.value == 0) {
1314 error = ESRCH;
1315 goto out;
1316 }
1317 start = (void **)symval.value;
1318
1319 /* get address of last entry */
1320 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1321 error = link_elf_lookup_symbol(lf, setsym, &sym);
1322 if (error)
1323 goto out;
1324 link_elf_symbol_values(lf, sym, &symval);
1325 if (symval.value == 0) {
1326 error = ESRCH;
1327 goto out;
1328 }
1329 stop = (void **)symval.value;
1330
1331 /* and the number of entries */
1332 count = stop - start;
1333
1334 /* and copy out */
1335 if (startp)
1336 *startp = start;
1337 if (stopp)
1338 *stopp = stop;
1339 if (countp)
1340 *countp = count;
1341
1342 out:
1343 free(setsym, M_LINKER);
1344 return error;
1345 }
1346
1347 static int
1348 link_elf_each_function_name(linker_file_t file,
1349 int (*callback)(const char *, void *), void *opaque) {
1350 elf_file_t ef = (elf_file_t)file;
1351 const Elf_Sym* symp;
1352 int i, error;
1353
1354 /* Exhaustive search */
1355 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1356 if (symp->st_value != 0 &&
1357 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1358 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1359 if (error)
1360 return (error);
1361 }
1362 }
1363 return (0);
1364 }
1365
1366 static int
1367 link_elf_each_function_nameval(linker_file_t file,
1368 linker_function_nameval_callback_t callback, void *opaque)
1369 {
1370 linker_symval_t symval;
1371 elf_file_t ef = (elf_file_t)file;
1372 const Elf_Sym* symp;
1373 int i, error;
1374
1375 /* Exhaustive search */
1376 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1377 if (symp->st_value != 0 &&
1378 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1379 error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1380 if (error)
1381 return (error);
1382 error = callback(file, i, &symval, opaque);
1383 if (error)
1384 return (error);
1385 }
1386 }
1387 return (0);
1388 }
1389
1390 #ifdef __ia64__
1391 /*
1392 * Each KLD has its own GP. The GP value for each load module is given by
1393 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1394 * don't have direct access to the ELF file structure. The link_elf_get_gp()
1395 * function returns the GP given a pointer to a generic linker file struct.
1396 */
1397 Elf_Addr
1398 link_elf_get_gp(linker_file_t lf)
1399 {
1400 elf_file_t ef = (elf_file_t)lf;
1401 return (Elf_Addr)ef->got;
1402 }
1403 #endif
1404
1405 const Elf_Sym *
1406 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1407 {
1408 elf_file_t ef = (elf_file_t)lf;
1409
1410 if (symidx >= ef->nchains)
1411 return (NULL);
1412 return (ef->symtab + symidx);
1413 }
1414
1415 const char *
1416 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1417 {
1418 elf_file_t ef = (elf_file_t)lf;
1419 const Elf_Sym *sym;
1420
1421 if (symidx >= ef->nchains)
1422 return (NULL);
1423 sym = ef->symtab + symidx;
1424 return (ef->strtab + sym->st_name);
1425 }
1426
1427 /*
1428 * Symbol lookup function that can be used when the symbol index is known (ie
1429 * in relocations). It uses the symbol index instead of doing a fully fledged
1430 * hash table based lookup when such is valid. For example for local symbols.
1431 * This is not only more efficient, it's also more correct. It's not always
1432 * the case that the symbol can be found through the hash table.
1433 */
1434 static Elf_Addr
1435 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1436 {
1437 elf_file_t ef = (elf_file_t)lf;
1438 const Elf_Sym *sym;
1439 const char *symbol;
1440
1441 /* Don't even try to lookup the symbol if the index is bogus. */
1442 if (symidx >= ef->nchains)
1443 return (0);
1444
1445 sym = ef->symtab + symidx;
1446
1447 /*
1448 * Don't do a full lookup when the symbol is local. It may even
1449 * fail because it may not be found through the hash table.
1450 */
1451 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1452 /* Force lookup failure when we have an insanity. */
1453 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1454 return (0);
1455 return ((Elf_Addr)ef->address + sym->st_value);
1456 }
1457
1458 /*
1459 * XXX we can avoid doing a hash table based lookup for global
1460 * symbols as well. This however is not always valid, so we'll
1461 * just do it the hard way for now. Performance tweaks can
1462 * always be added.
1463 */
1464
1465 symbol = ef->strtab + sym->st_name;
1466
1467 /* Force a lookup failure if the symbol name is bogus. */
1468 if (*symbol == 0)
1469 return (0);
1470
1471 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1472 }
1473
1474 static void
1475 link_elf_reloc_local(linker_file_t lf)
1476 {
1477 const Elf_Rel *rellim;
1478 const Elf_Rel *rel;
1479 const Elf_Rela *relalim;
1480 const Elf_Rela *rela;
1481 elf_file_t ef = (elf_file_t)lf;
1482
1483 /* Perform relocations without addend if there are any: */
1484 if ((rel = ef->rel) != NULL) {
1485 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1486 while (rel < rellim) {
1487 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1488 elf_lookup);
1489 rel++;
1490 }
1491 }
1492
1493 /* Perform relocations with addend if there are any: */
1494 if ((rela = ef->rela) != NULL) {
1495 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1496 while (rela < relalim) {
1497 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1498 elf_lookup);
1499 rela++;
1500 }
1501 }
1502 }
1503
1504 static long
1505 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1506 {
1507 elf_file_t ef = (elf_file_t)lf;
1508
1509 *symtab = ef->ddbsymtab;
1510
1511 if (*symtab == NULL)
1512 return (0);
1513
1514 return (ef->ddbsymcnt);
1515 }
1516
1517 static long
1518 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1519 {
1520 elf_file_t ef = (elf_file_t)lf;
1521
1522 *strtab = ef->ddbstrtab;
1523
1524 if (*strtab == NULL)
1525 return (0);
1526
1527 return (ef->ddbstrcnt);
1528 }
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