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("$FreeBSD$");
29
30 #include "opt_ddb.h"
31 #include "opt_gdb.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #ifdef GPROF
36 #include <sys/gmon.h>
37 #endif
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/mount.h>
43 #include <sys/pcpu.h>
44 #include <sys/proc.h>
45 #include <sys/namei.h>
46 #include <sys/fcntl.h>
47 #include <sys/vnode.h>
48 #include <sys/linker.h>
49
50 #include <machine/elf.h>
51
52 #include <net/vnet.h>
53
54 #include <security/mac/mac_framework.h>
55
56 #include <vm/vm.h>
57 #include <vm/vm_param.h>
58 #ifdef SPARSE_MAPPING
59 #include <vm/vm_object.h>
60 #include <vm/vm_kern.h>
61 #include <vm/vm_extern.h>
62 #endif
63 #include <vm/pmap.h>
64 #include <vm/vm_map.h>
65
66 #include <sys/link_elf.h>
67
68 #ifdef DDB_CTF
69 #include <net/zlib.h>
70 #endif
71
72 #include "linker_if.h"
73
74 #define MAXSEGS 4
75
76 typedef struct elf_file {
77 struct linker_file lf; /* Common fields */
78 int preloaded; /* Was file pre-loaded */
79 caddr_t address; /* Relocation address */
80 #ifdef SPARSE_MAPPING
81 vm_object_t object; /* VM object to hold file pages */
82 #endif
83 Elf_Dyn *dynamic; /* Symbol table etc. */
84 Elf_Hashelt nbuckets; /* DT_HASH info */
85 Elf_Hashelt nchains;
86 const Elf_Hashelt *buckets;
87 const Elf_Hashelt *chains;
88 caddr_t hash;
89 caddr_t strtab; /* DT_STRTAB */
90 int strsz; /* DT_STRSZ */
91 const Elf_Sym *symtab; /* DT_SYMTAB */
92 Elf_Addr *got; /* DT_PLTGOT */
93 const Elf_Rel *pltrel; /* DT_JMPREL */
94 int pltrelsize; /* DT_PLTRELSZ */
95 const Elf_Rela *pltrela; /* DT_JMPREL */
96 int pltrelasize; /* DT_PLTRELSZ */
97 const Elf_Rel *rel; /* DT_REL */
98 int relsize; /* DT_RELSZ */
99 const Elf_Rela *rela; /* DT_RELA */
100 int relasize; /* DT_RELASZ */
101 caddr_t modptr;
102 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
103 long ddbsymcnt; /* Number of symbols */
104 caddr_t ddbstrtab; /* String table */
105 long ddbstrcnt; /* number of bytes in string table */
106 caddr_t symbase; /* malloc'ed symbold base */
107 caddr_t strbase; /* malloc'ed string base */
108 caddr_t ctftab; /* CTF table */
109 long ctfcnt; /* number of bytes in CTF table */
110 caddr_t ctfoff; /* CTF offset table */
111 caddr_t typoff; /* Type offset table */
112 long typlen; /* Number of type entries. */
113 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
114 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
115 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
116 #ifdef VIMAGE
117 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
118 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
119 Elf_Addr vnet_base; /* Relocated vnet set address. */
120 #endif
121 #ifdef GDB
122 struct link_map gdb; /* hooks for gdb */
123 #endif
124 } *elf_file_t;
125
126 struct elf_set {
127 Elf_Addr es_start;
128 Elf_Addr es_stop;
129 Elf_Addr es_base;
130 TAILQ_ENTRY(elf_set) es_link;
131 };
132
133 TAILQ_HEAD(elf_set_head, elf_set);
134
135 #include <kern/kern_ctf.c>
136
137 static int link_elf_link_common_finish(linker_file_t);
138 static int link_elf_link_preload(linker_class_t cls,
139 const char *, linker_file_t *);
140 static int link_elf_link_preload_finish(linker_file_t);
141 static int link_elf_load_file(linker_class_t, const char *,
142 linker_file_t *);
143 static int link_elf_lookup_symbol(linker_file_t, const char *,
144 c_linker_sym_t *);
145 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
146 linker_symval_t *);
147 static int link_elf_search_symbol(linker_file_t, caddr_t,
148 c_linker_sym_t *, long *);
149
150 static void link_elf_unload_file(linker_file_t);
151 static void link_elf_unload_preload(linker_file_t);
152 static int link_elf_lookup_set(linker_file_t, const char *,
153 void ***, void ***, int *);
154 static int link_elf_each_function_name(linker_file_t,
155 int (*)(const char *, void *), void *);
156 static int link_elf_each_function_nameval(linker_file_t,
157 linker_function_nameval_callback_t, void *);
158 static void link_elf_reloc_local(linker_file_t);
159 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
160 static long link_elf_strtab_get(linker_file_t, caddr_t *);
161 static Elf_Addr elf_lookup(linker_file_t, Elf_Size, int);
162
163 static kobj_method_t link_elf_methods[] = {
164 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
165 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
166 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
167 KOBJMETHOD(linker_unload, link_elf_unload_file),
168 KOBJMETHOD(linker_load_file, link_elf_load_file),
169 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
170 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
171 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
172 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
173 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
174 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
175 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
176 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
177 { 0, 0 }
178 };
179
180 static struct linker_class link_elf_class = {
181 #if ELF_TARG_CLASS == ELFCLASS32
182 "elf32",
183 #else
184 "elf64",
185 #endif
186 link_elf_methods, sizeof(struct elf_file)
187 };
188
189 static int parse_dynamic(elf_file_t);
190 static int relocate_file(elf_file_t);
191 static int link_elf_preload_parse_symbols(elf_file_t);
192
193 static struct elf_set_head set_pcpu_list;
194 #ifdef VIMAGE
195 static struct elf_set_head set_vnet_list;
196 #endif
197
198 static void
199 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
200 {
201 struct elf_set *set, *iter;
202
203 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
204 set->es_start = start;
205 set->es_stop = stop;
206 set->es_base = base;
207
208 TAILQ_FOREACH(iter, list, es_link) {
209
210 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
211 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
212 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
213 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
214 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
215
216 if (iter->es_start > set->es_start) {
217 TAILQ_INSERT_BEFORE(iter, set, es_link);
218 break;
219 }
220 }
221
222 if (iter == NULL)
223 TAILQ_INSERT_TAIL(list, set, es_link);
224 }
225
226 static int
227 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
228 {
229 struct elf_set *set;
230
231 TAILQ_FOREACH(set, list, es_link) {
232 if (addr < set->es_start)
233 return (0);
234 if (addr < set->es_stop) {
235 *start = set->es_start;
236 *base = set->es_base;
237 return (1);
238 }
239 }
240
241 return (0);
242 }
243
244 static void
245 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
246 {
247 struct elf_set *set;
248
249 TAILQ_FOREACH(set, list, es_link) {
250 if (start < set->es_start)
251 break;
252 if (start == set->es_start) {
253 TAILQ_REMOVE(list, set, es_link);
254 free(set, M_LINKER);
255 return;
256 }
257 }
258 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
259 (uintmax_t)start));
260 }
261
262 #ifdef GDB
263 static void r_debug_state(struct r_debug *, struct link_map *);
264
265 /*
266 * A list of loaded modules for GDB to use for loading symbols.
267 */
268 struct r_debug r_debug;
269
270 #define GDB_STATE(s) do { \
271 r_debug.r_state = s; r_debug_state(NULL, NULL); \
272 } while (0)
273
274 /*
275 * Function for the debugger to set a breakpoint on to gain control.
276 */
277 static void
278 r_debug_state(struct r_debug *dummy_one __unused,
279 struct link_map *dummy_two __unused)
280 {
281 }
282
283 static void
284 link_elf_add_gdb(struct link_map *l)
285 {
286 struct link_map *prev;
287
288 l->l_next = NULL;
289
290 if (r_debug.r_map == NULL) {
291 /* Add first. */
292 l->l_prev = NULL;
293 r_debug.r_map = l;
294 } else {
295 /* Append to list. */
296 for (prev = r_debug.r_map;
297 prev->l_next != NULL;
298 prev = prev->l_next)
299 ;
300 l->l_prev = prev;
301 prev->l_next = l;
302 }
303 }
304
305 static void
306 link_elf_delete_gdb(struct link_map *l)
307 {
308 if (l->l_prev == NULL) {
309 /* Remove first. */
310 if ((r_debug.r_map = l->l_next) != NULL)
311 l->l_next->l_prev = NULL;
312 } else {
313 /* Remove any but first. */
314 if ((l->l_prev->l_next = l->l_next) != NULL)
315 l->l_next->l_prev = l->l_prev;
316 }
317 }
318 #endif /* GDB */
319
320 #ifdef __ia64__
321 Elf_Addr link_elf_get_gp(linker_file_t);
322 #endif
323
324 /*
325 * The kernel symbol table starts here.
326 */
327 extern struct _dynamic _DYNAMIC;
328
329 static void
330 link_elf_error(const char *filename, const char *s)
331 {
332 if (filename == NULL)
333 printf("kldload: %s\n", s);
334 else
335 printf("kldload: %s: %s\n", filename, s);
336 }
337
338 /*
339 * Actions performed after linking/loading both the preloaded kernel and any
340 * modules; whether preloaded or dynamicly loaded.
341 */
342 static int
343 link_elf_link_common_finish(linker_file_t lf)
344 {
345 #ifdef GDB
346 elf_file_t ef = (elf_file_t)lf;
347 char *newfilename;
348 #endif
349 int error;
350
351 /* Notify MD code that a module is being loaded. */
352 error = elf_cpu_load_file(lf);
353 if (error != 0)
354 return (error);
355
356 #ifdef GDB
357 GDB_STATE(RT_ADD);
358 ef->gdb.l_addr = lf->address;
359 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
360 strcpy(newfilename, lf->filename);
361 ef->gdb.l_name = newfilename;
362 ef->gdb.l_ld = ef->dynamic;
363 link_elf_add_gdb(&ef->gdb);
364 GDB_STATE(RT_CONSISTENT);
365 #endif
366
367 return (0);
368 }
369
370 static void
371 link_elf_init(void* arg)
372 {
373 Elf_Dyn *dp;
374 caddr_t modptr, baseptr, sizeptr;
375 elf_file_t ef;
376 char *modname;
377
378 linker_add_class(&link_elf_class);
379
380 dp = (Elf_Dyn *)&_DYNAMIC;
381 modname = NULL;
382 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
383 if (modptr == NULL)
384 modptr = preload_search_by_type("elf kernel");
385 if (modptr != NULL)
386 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
387 if (modname == NULL)
388 modname = "kernel";
389 linker_kernel_file = linker_make_file(modname, &link_elf_class);
390 if (linker_kernel_file == NULL)
391 panic("%s: Can't create linker structures for kernel",
392 __func__);
393
394 ef = (elf_file_t) linker_kernel_file;
395 ef->preloaded = 1;
396 ef->address = 0;
397 #ifdef SPARSE_MAPPING
398 ef->object = 0;
399 #endif
400 ef->dynamic = dp;
401
402 if (dp != NULL)
403 parse_dynamic(ef);
404 linker_kernel_file->address = (caddr_t) KERNBASE;
405 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
406
407 if (modptr != NULL) {
408 ef->modptr = modptr;
409 baseptr = preload_search_info(modptr, MODINFO_ADDR);
410 if (baseptr != NULL)
411 linker_kernel_file->address = *(caddr_t *)baseptr;
412 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
413 if (sizeptr != NULL)
414 linker_kernel_file->size = *(size_t *)sizeptr;
415 }
416 (void)link_elf_preload_parse_symbols(ef);
417
418 #ifdef GDB
419 r_debug.r_map = NULL;
420 r_debug.r_brk = r_debug_state;
421 r_debug.r_state = RT_CONSISTENT;
422 #endif
423
424 (void)link_elf_link_common_finish(linker_kernel_file);
425 linker_kernel_file->flags |= LINKER_FILE_LINKED;
426 TAILQ_INIT(&set_pcpu_list);
427 #ifdef VIMAGE
428 TAILQ_INIT(&set_vnet_list);
429 #endif
430 }
431
432 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
433
434 static int
435 link_elf_preload_parse_symbols(elf_file_t ef)
436 {
437 caddr_t pointer;
438 caddr_t ssym, esym, base;
439 caddr_t strtab;
440 int strcnt;
441 Elf_Sym *symtab;
442 int symcnt;
443
444 if (ef->modptr == NULL)
445 return (0);
446 pointer = preload_search_info(ef->modptr,
447 MODINFO_METADATA | MODINFOMD_SSYM);
448 if (pointer == NULL)
449 return (0);
450 ssym = *(caddr_t *)pointer;
451 pointer = preload_search_info(ef->modptr,
452 MODINFO_METADATA | MODINFOMD_ESYM);
453 if (pointer == NULL)
454 return (0);
455 esym = *(caddr_t *)pointer;
456
457 base = ssym;
458
459 symcnt = *(long *)base;
460 base += sizeof(long);
461 symtab = (Elf_Sym *)base;
462 base += roundup(symcnt, sizeof(long));
463
464 if (base > esym || base < ssym) {
465 printf("Symbols are corrupt!\n");
466 return (EINVAL);
467 }
468
469 strcnt = *(long *)base;
470 base += sizeof(long);
471 strtab = base;
472 base += roundup(strcnt, sizeof(long));
473
474 if (base > esym || base < ssym) {
475 printf("Symbols are corrupt!\n");
476 return (EINVAL);
477 }
478
479 ef->ddbsymtab = symtab;
480 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
481 ef->ddbstrtab = strtab;
482 ef->ddbstrcnt = strcnt;
483
484 return (0);
485 }
486
487 static int
488 parse_dynamic(elf_file_t ef)
489 {
490 Elf_Dyn *dp;
491 int plttype = DT_REL;
492
493 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
494 switch (dp->d_tag) {
495 case DT_HASH:
496 {
497 /* From src/libexec/rtld-elf/rtld.c */
498 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
499 (ef->address + dp->d_un.d_ptr);
500 ef->nbuckets = hashtab[0];
501 ef->nchains = hashtab[1];
502 ef->buckets = hashtab + 2;
503 ef->chains = ef->buckets + ef->nbuckets;
504 break;
505 }
506 case DT_STRTAB:
507 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
508 break;
509 case DT_STRSZ:
510 ef->strsz = dp->d_un.d_val;
511 break;
512 case DT_SYMTAB:
513 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
514 break;
515 case DT_SYMENT:
516 if (dp->d_un.d_val != sizeof(Elf_Sym))
517 return (ENOEXEC);
518 break;
519 case DT_PLTGOT:
520 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
521 break;
522 case DT_REL:
523 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
524 break;
525 case DT_RELSZ:
526 ef->relsize = dp->d_un.d_val;
527 break;
528 case DT_RELENT:
529 if (dp->d_un.d_val != sizeof(Elf_Rel))
530 return (ENOEXEC);
531 break;
532 case DT_JMPREL:
533 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
534 break;
535 case DT_PLTRELSZ:
536 ef->pltrelsize = dp->d_un.d_val;
537 break;
538 case DT_RELA:
539 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
540 break;
541 case DT_RELASZ:
542 ef->relasize = dp->d_un.d_val;
543 break;
544 case DT_RELAENT:
545 if (dp->d_un.d_val != sizeof(Elf_Rela))
546 return (ENOEXEC);
547 break;
548 case DT_PLTREL:
549 plttype = dp->d_un.d_val;
550 if (plttype != DT_REL && plttype != DT_RELA)
551 return (ENOEXEC);
552 break;
553 #ifdef GDB
554 case DT_DEBUG:
555 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
556 break;
557 #endif
558 }
559 }
560
561 if (plttype == DT_RELA) {
562 ef->pltrela = (const Elf_Rela *)ef->pltrel;
563 ef->pltrel = NULL;
564 ef->pltrelasize = ef->pltrelsize;
565 ef->pltrelsize = 0;
566 }
567
568 ef->ddbsymtab = ef->symtab;
569 ef->ddbsymcnt = ef->nchains;
570 ef->ddbstrtab = ef->strtab;
571 ef->ddbstrcnt = ef->strsz;
572
573 return (0);
574 }
575
576 static int
577 parse_dpcpu(elf_file_t ef)
578 {
579 int count;
580 int error;
581
582 ef->pcpu_start = 0;
583 ef->pcpu_stop = 0;
584 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
585 (void ***)&ef->pcpu_stop, &count);
586 /* Error just means there is no pcpu set to relocate. */
587 if (error != 0)
588 return (0);
589 count *= sizeof(void *);
590 /*
591 * Allocate space in the primary pcpu area. Copy in our
592 * initialization from the data section and then initialize
593 * all per-cpu storage from that.
594 */
595 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
596 if (ef->pcpu_base == 0)
597 return (ENOSPC);
598 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
599 dpcpu_copy((void *)ef->pcpu_base, count);
600 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
601 ef->pcpu_base);
602
603 return (0);
604 }
605
606 #ifdef VIMAGE
607 static int
608 parse_vnet(elf_file_t ef)
609 {
610 int count;
611 int error;
612
613 ef->vnet_start = 0;
614 ef->vnet_stop = 0;
615 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
616 (void ***)&ef->vnet_stop, &count);
617 /* Error just means there is no vnet data set to relocate. */
618 if (error != 0)
619 return (0);
620 count *= sizeof(void *);
621 /*
622 * Allocate space in the primary vnet area. Copy in our
623 * initialization from the data section and then initialize
624 * all per-vnet storage from that.
625 */
626 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
627 if (ef->vnet_base == 0)
628 return (ENOSPC);
629 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
630 vnet_data_copy((void *)ef->vnet_base, count);
631 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
632 ef->vnet_base);
633
634 return (0);
635 }
636 #endif
637
638 static int
639 link_elf_link_preload(linker_class_t cls,
640 const char* filename, linker_file_t *result)
641 {
642 caddr_t modptr, baseptr, sizeptr, dynptr;
643 char *type;
644 elf_file_t ef;
645 linker_file_t lf;
646 int error;
647 vm_offset_t dp;
648
649 /* Look to see if we have the file preloaded */
650 modptr = preload_search_by_name(filename);
651 if (modptr == NULL)
652 return (ENOENT);
653
654 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
655 baseptr = preload_search_info(modptr, MODINFO_ADDR);
656 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
657 dynptr = preload_search_info(modptr,
658 MODINFO_METADATA | MODINFOMD_DYNAMIC);
659 if (type == NULL ||
660 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
661 strcmp(type, "elf module") != 0))
662 return (EFTYPE);
663 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
664 return (EINVAL);
665
666 lf = linker_make_file(filename, &link_elf_class);
667 if (lf == NULL)
668 return (ENOMEM);
669
670 ef = (elf_file_t) lf;
671 ef->preloaded = 1;
672 ef->modptr = modptr;
673 ef->address = *(caddr_t *)baseptr;
674 #ifdef SPARSE_MAPPING
675 ef->object = 0;
676 #endif
677 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
678 ef->dynamic = (Elf_Dyn *)dp;
679 lf->address = ef->address;
680 lf->size = *(size_t *)sizeptr;
681
682 error = parse_dynamic(ef);
683 if (error == 0)
684 error = parse_dpcpu(ef);
685 #ifdef VIMAGE
686 if (error == 0)
687 error = parse_vnet(ef);
688 #endif
689 if (error != 0) {
690 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
691 return (error);
692 }
693 link_elf_reloc_local(lf);
694 *result = lf;
695 return (0);
696 }
697
698 static int
699 link_elf_link_preload_finish(linker_file_t lf)
700 {
701 elf_file_t ef;
702 int error;
703
704 ef = (elf_file_t) lf;
705 #if 0 /* this will be more trouble than it's worth for now */
706 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
707 if (dp->d_tag != DT_NEEDED)
708 continue;
709 modname = ef->strtab + dp->d_un.d_val;
710 error = linker_load_module(modname, lf);
711 if (error != 0)
712 goto out;
713 }
714 #endif
715 error = relocate_file(ef);
716 if (error != 0)
717 return (error);
718 (void)link_elf_preload_parse_symbols(ef);
719
720 return (link_elf_link_common_finish(lf));
721 }
722
723 static int
724 link_elf_load_file(linker_class_t cls, const char* filename,
725 linker_file_t* result)
726 {
727 struct nameidata nd;
728 struct thread* td = curthread; /* XXX */
729 Elf_Ehdr *hdr;
730 caddr_t firstpage;
731 int nbytes, i;
732 Elf_Phdr *phdr;
733 Elf_Phdr *phlimit;
734 Elf_Phdr *segs[MAXSEGS];
735 int nsegs;
736 Elf_Phdr *phdyn;
737 Elf_Phdr *phphdr;
738 caddr_t mapbase;
739 size_t mapsize;
740 Elf_Off base_offset;
741 Elf_Addr base_vaddr;
742 Elf_Addr base_vlimit;
743 int error = 0;
744 int resid, flags;
745 elf_file_t ef;
746 linker_file_t lf;
747 Elf_Shdr *shdr;
748 int symtabindex;
749 int symstrindex;
750 int symcnt;
751 int strcnt;
752 int vfslocked;
753
754 shdr = NULL;
755 lf = NULL;
756
757 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
758 flags = FREAD;
759 error = vn_open(&nd, &flags, 0, NULL);
760 if (error != 0)
761 return (error);
762 vfslocked = NDHASGIANT(&nd);
763 NDFREE(&nd, NDF_ONLY_PNBUF);
764 if (nd.ni_vp->v_type != VREG) {
765 error = ENOEXEC;
766 firstpage = NULL;
767 goto out;
768 }
769 #ifdef MAC
770 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
771 if (error != 0) {
772 firstpage = NULL;
773 goto out;
774 }
775 #endif
776
777 /*
778 * Read the elf header from the file.
779 */
780 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
781 hdr = (Elf_Ehdr *)firstpage;
782 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
783 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
784 &resid, td);
785 nbytes = PAGE_SIZE - resid;
786 if (error != 0)
787 goto out;
788
789 if (!IS_ELF(*hdr)) {
790 error = ENOEXEC;
791 goto out;
792 }
793
794 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
795 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
796 link_elf_error(filename, "Unsupported file layout");
797 error = ENOEXEC;
798 goto out;
799 }
800 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
801 hdr->e_version != EV_CURRENT) {
802 link_elf_error(filename, "Unsupported file version");
803 error = ENOEXEC;
804 goto out;
805 }
806 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
807 error = ENOSYS;
808 goto out;
809 }
810 if (hdr->e_machine != ELF_TARG_MACH) {
811 link_elf_error(filename, "Unsupported machine");
812 error = ENOEXEC;
813 goto out;
814 }
815
816 /*
817 * We rely on the program header being in the first page.
818 * This is not strictly required by the ABI specification, but
819 * it seems to always true in practice. And, it simplifies
820 * things considerably.
821 */
822 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
823 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
824 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
825 link_elf_error(filename, "Unreadable program headers");
826
827 /*
828 * Scan the program header entries, and save key information.
829 *
830 * We rely on there being exactly two load segments, text and data,
831 * in that order.
832 */
833 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
834 phlimit = phdr + hdr->e_phnum;
835 nsegs = 0;
836 phdyn = NULL;
837 phphdr = NULL;
838 while (phdr < phlimit) {
839 switch (phdr->p_type) {
840 case PT_LOAD:
841 if (nsegs == MAXSEGS) {
842 link_elf_error(filename, "Too many sections");
843 error = ENOEXEC;
844 goto out;
845 }
846 /*
847 * XXX: We just trust they come in right order ??
848 */
849 segs[nsegs] = phdr;
850 ++nsegs;
851 break;
852
853 case PT_PHDR:
854 phphdr = phdr;
855 break;
856
857 case PT_DYNAMIC:
858 phdyn = phdr;
859 break;
860
861 case PT_INTERP:
862 error = ENOSYS;
863 goto out;
864 }
865
866 ++phdr;
867 }
868 if (phdyn == NULL) {
869 link_elf_error(filename, "Object is not dynamically-linked");
870 error = ENOEXEC;
871 goto out;
872 }
873 if (nsegs == 0) {
874 link_elf_error(filename, "No sections");
875 error = ENOEXEC;
876 goto out;
877 }
878
879 /*
880 * Allocate the entire address space of the object, to stake
881 * out our contiguous region, and to establish the base
882 * address for relocation.
883 */
884 base_offset = trunc_page(segs[0]->p_offset);
885 base_vaddr = trunc_page(segs[0]->p_vaddr);
886 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
887 segs[nsegs - 1]->p_memsz);
888 mapsize = base_vlimit - base_vaddr;
889
890 lf = linker_make_file(filename, &link_elf_class);
891 if (lf == NULL) {
892 error = ENOMEM;
893 goto out;
894 }
895
896 ef = (elf_file_t) lf;
897 #ifdef SPARSE_MAPPING
898 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
899 if (ef->object == NULL) {
900 error = ENOMEM;
901 goto out;
902 }
903 ef->address = (caddr_t) vm_map_min(kernel_map);
904 error = vm_map_find(kernel_map, ef->object, 0,
905 (vm_offset_t *) &ef->address, mapsize, 1,
906 VM_PROT_ALL, VM_PROT_ALL, 0);
907 if (error != 0) {
908 vm_object_deallocate(ef->object);
909 ef->object = 0;
910 goto out;
911 }
912 #else
913 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
914 #endif
915 mapbase = ef->address;
916
917 /*
918 * Read the text and data sections and zero the bss.
919 */
920 for (i = 0; i < nsegs; i++) {
921 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
922 error = vn_rdwr(UIO_READ, nd.ni_vp,
923 segbase, segs[i]->p_filesz, segs[i]->p_offset,
924 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
925 &resid, td);
926 if (error != 0)
927 goto out;
928 bzero(segbase + segs[i]->p_filesz,
929 segs[i]->p_memsz - segs[i]->p_filesz);
930
931 #ifdef SPARSE_MAPPING
932 /*
933 * Wire down the pages
934 */
935 error = vm_map_wire(kernel_map,
936 (vm_offset_t) segbase,
937 (vm_offset_t) segbase + segs[i]->p_memsz,
938 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
939 if (error != KERN_SUCCESS) {
940 error = ENOMEM;
941 goto out;
942 }
943 #endif
944 }
945
946 #ifdef GPROF
947 /* Update profiling information with the new text segment. */
948 mtx_lock(&Giant);
949 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
950 segs[0]->p_memsz));
951 mtx_unlock(&Giant);
952 #endif
953
954 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
955
956 lf->address = ef->address;
957 lf->size = mapsize;
958
959 error = parse_dynamic(ef);
960 if (error != 0)
961 goto out;
962 error = parse_dpcpu(ef);
963 if (error != 0)
964 goto out;
965 #ifdef VIMAGE
966 error = parse_vnet(ef);
967 if (error != 0)
968 goto out;
969 #endif
970 link_elf_reloc_local(lf);
971
972 VOP_UNLOCK(nd.ni_vp, 0);
973 error = linker_load_dependencies(lf);
974 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
975 if (error != 0)
976 goto out;
977 #if 0 /* this will be more trouble than it's worth for now */
978 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
979 if (dp->d_tag != DT_NEEDED)
980 continue;
981 modname = ef->strtab + dp->d_un.d_val;
982 error = linker_load_module(modname, lf);
983 if (error != 0)
984 goto out;
985 }
986 #endif
987 error = relocate_file(ef);
988 if (error != 0)
989 goto out;
990
991 /*
992 * Try and load the symbol table if it's present. (you can
993 * strip it!)
994 */
995 nbytes = hdr->e_shnum * hdr->e_shentsize;
996 if (nbytes == 0 || hdr->e_shoff == 0)
997 goto nosyms;
998 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
999 error = vn_rdwr(UIO_READ, nd.ni_vp,
1000 (caddr_t)shdr, nbytes, hdr->e_shoff,
1001 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1002 &resid, td);
1003 if (error != 0)
1004 goto out;
1005 symtabindex = -1;
1006 symstrindex = -1;
1007 for (i = 0; i < hdr->e_shnum; i++) {
1008 if (shdr[i].sh_type == SHT_SYMTAB) {
1009 symtabindex = i;
1010 symstrindex = shdr[i].sh_link;
1011 }
1012 }
1013 if (symtabindex < 0 || symstrindex < 0)
1014 goto nosyms;
1015
1016 symcnt = shdr[symtabindex].sh_size;
1017 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1018 strcnt = shdr[symstrindex].sh_size;
1019 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1020
1021 error = vn_rdwr(UIO_READ, nd.ni_vp,
1022 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1023 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1024 &resid, td);
1025 if (error != 0)
1026 goto out;
1027 error = vn_rdwr(UIO_READ, nd.ni_vp,
1028 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1029 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1030 &resid, td);
1031 if (error != 0)
1032 goto out;
1033
1034 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1035 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1036 ef->ddbstrcnt = strcnt;
1037 ef->ddbstrtab = ef->strbase;
1038
1039 error = link_elf_link_common_finish(lf);
1040 if (error != 0)
1041 goto out;
1042
1043 nosyms:
1044 *result = lf;
1045
1046 out:
1047 VOP_UNLOCK(nd.ni_vp, 0);
1048 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1049 VFS_UNLOCK_GIANT(vfslocked);
1050 if (error != 0 && lf != NULL)
1051 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1052 if (shdr != NULL)
1053 free(shdr, M_LINKER);
1054 if (firstpage != NULL)
1055 free(firstpage, M_LINKER);
1056
1057 return (error);
1058 }
1059
1060 Elf_Addr
1061 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1062 {
1063 elf_file_t ef;
1064
1065 ef = (elf_file_t)lf;
1066 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1067 return ((x - ef->pcpu_start) + ef->pcpu_base);
1068 #ifdef VIMAGE
1069 if (x >= ef->vnet_start && x < ef->vnet_stop)
1070 return ((x - ef->vnet_start) + ef->vnet_base);
1071 #endif
1072 return (x);
1073 }
1074
1075
1076 static void
1077 link_elf_unload_file(linker_file_t file)
1078 {
1079 elf_file_t ef = (elf_file_t) file;
1080
1081 if (ef->pcpu_base != 0) {
1082 dpcpu_free((void *)ef->pcpu_base,
1083 ef->pcpu_stop - ef->pcpu_start);
1084 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1085 }
1086 #ifdef VIMAGE
1087 if (ef->vnet_base != 0) {
1088 vnet_data_free((void *)ef->vnet_base,
1089 ef->vnet_stop - ef->vnet_start);
1090 elf_set_delete(&set_vnet_list, ef->vnet_start);
1091 }
1092 #endif
1093 #ifdef GDB
1094 if (ef->gdb.l_ld != NULL) {
1095 GDB_STATE(RT_DELETE);
1096 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1097 link_elf_delete_gdb(&ef->gdb);
1098 GDB_STATE(RT_CONSISTENT);
1099 }
1100 #endif
1101
1102 /* Notify MD code that a module is being unloaded. */
1103 elf_cpu_unload_file(file);
1104
1105 if (ef->preloaded) {
1106 link_elf_unload_preload(file);
1107 return;
1108 }
1109
1110 #ifdef SPARSE_MAPPING
1111 if (ef->object != NULL) {
1112 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1113 (vm_offset_t) ef->address
1114 + (ef->object->size << PAGE_SHIFT));
1115 }
1116 #else
1117 if (ef->address != NULL)
1118 free(ef->address, M_LINKER);
1119 #endif
1120 if (ef->symbase != NULL)
1121 free(ef->symbase, M_LINKER);
1122 if (ef->strbase != NULL)
1123 free(ef->strbase, M_LINKER);
1124 if (ef->ctftab != NULL)
1125 free(ef->ctftab, M_LINKER);
1126 if (ef->ctfoff != NULL)
1127 free(ef->ctfoff, M_LINKER);
1128 if (ef->typoff != NULL)
1129 free(ef->typoff, M_LINKER);
1130 }
1131
1132 static void
1133 link_elf_unload_preload(linker_file_t file)
1134 {
1135 if (file->filename != NULL)
1136 preload_delete_name(file->filename);
1137 }
1138
1139 static const char *
1140 symbol_name(elf_file_t ef, Elf_Size r_info)
1141 {
1142 const Elf_Sym *ref;
1143
1144 if (ELF_R_SYM(r_info)) {
1145 ref = ef->symtab + ELF_R_SYM(r_info);
1146 return (ef->strtab + ref->st_name);
1147 }
1148 return (NULL);
1149 }
1150
1151 static int
1152 relocate_file(elf_file_t ef)
1153 {
1154 const Elf_Rel *rellim;
1155 const Elf_Rel *rel;
1156 const Elf_Rela *relalim;
1157 const Elf_Rela *rela;
1158 const char *symname;
1159
1160 /* Perform relocations without addend if there are any: */
1161 rel = ef->rel;
1162 if (rel != NULL) {
1163 rellim = (const Elf_Rel *)
1164 ((const char *)ef->rel + ef->relsize);
1165 while (rel < rellim) {
1166 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1167 ELF_RELOC_REL, elf_lookup)) {
1168 symname = symbol_name(ef, rel->r_info);
1169 printf("link_elf: symbol %s undefined\n", symname);
1170 return (ENOENT);
1171 }
1172 rel++;
1173 }
1174 }
1175
1176 /* Perform relocations with addend if there are any: */
1177 rela = ef->rela;
1178 if (rela != NULL) {
1179 relalim = (const Elf_Rela *)
1180 ((const char *)ef->rela + ef->relasize);
1181 while (rela < relalim) {
1182 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1183 ELF_RELOC_RELA, elf_lookup)) {
1184 symname = symbol_name(ef, rela->r_info);
1185 printf("link_elf: symbol %s undefined\n",
1186 symname);
1187 return (ENOENT);
1188 }
1189 rela++;
1190 }
1191 }
1192
1193 /* Perform PLT relocations without addend if there are any: */
1194 rel = ef->pltrel;
1195 if (rel != NULL) {
1196 rellim = (const Elf_Rel *)
1197 ((const char *)ef->pltrel + ef->pltrelsize);
1198 while (rel < rellim) {
1199 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1200 ELF_RELOC_REL, elf_lookup)) {
1201 symname = symbol_name(ef, rel->r_info);
1202 printf("link_elf: symbol %s undefined\n",
1203 symname);
1204 return (ENOENT);
1205 }
1206 rel++;
1207 }
1208 }
1209
1210 /* Perform relocations with addend if there are any: */
1211 rela = ef->pltrela;
1212 if (rela != NULL) {
1213 relalim = (const Elf_Rela *)
1214 ((const char *)ef->pltrela + ef->pltrelasize);
1215 while (rela < relalim) {
1216 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1217 ELF_RELOC_RELA, elf_lookup)) {
1218 symname = symbol_name(ef, rela->r_info);
1219 printf("link_elf: symbol %s undefined\n",
1220 symname);
1221 return (ENOENT);
1222 }
1223 rela++;
1224 }
1225 }
1226
1227 return (0);
1228 }
1229
1230 /*
1231 * Hash function for symbol table lookup. Don't even think about changing
1232 * this. It is specified by the System V ABI.
1233 */
1234 static unsigned long
1235 elf_hash(const char *name)
1236 {
1237 const unsigned char *p = (const unsigned char *) name;
1238 unsigned long h = 0;
1239 unsigned long g;
1240
1241 while (*p != '\0') {
1242 h = (h << 4) + *p++;
1243 if ((g = h & 0xf0000000) != 0)
1244 h ^= g >> 24;
1245 h &= ~g;
1246 }
1247 return (h);
1248 }
1249
1250 static int
1251 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1252 {
1253 elf_file_t ef = (elf_file_t) lf;
1254 unsigned long symnum;
1255 const Elf_Sym* symp;
1256 const char *strp;
1257 unsigned long hash;
1258 int i;
1259
1260 /* If we don't have a hash, bail. */
1261 if (ef->buckets == NULL || ef->nbuckets == 0) {
1262 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1263 return (ENOENT);
1264 }
1265
1266 /* First, search hashed global symbols */
1267 hash = elf_hash(name);
1268 symnum = ef->buckets[hash % ef->nbuckets];
1269
1270 while (symnum != STN_UNDEF) {
1271 if (symnum >= ef->nchains) {
1272 printf("%s: corrupt symbol table\n", __func__);
1273 return (ENOENT);
1274 }
1275
1276 symp = ef->symtab + symnum;
1277 if (symp->st_name == 0) {
1278 printf("%s: corrupt symbol table\n", __func__);
1279 return (ENOENT);
1280 }
1281
1282 strp = ef->strtab + symp->st_name;
1283
1284 if (strcmp(name, strp) == 0) {
1285 if (symp->st_shndx != SHN_UNDEF ||
1286 (symp->st_value != 0 &&
1287 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1288 *sym = (c_linker_sym_t) symp;
1289 return (0);
1290 }
1291 return (ENOENT);
1292 }
1293
1294 symnum = ef->chains[symnum];
1295 }
1296
1297 /* If we have not found it, look at the full table (if loaded) */
1298 if (ef->symtab == ef->ddbsymtab)
1299 return (ENOENT);
1300
1301 /* Exhaustive search */
1302 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1303 strp = ef->ddbstrtab + symp->st_name;
1304 if (strcmp(name, strp) == 0) {
1305 if (symp->st_shndx != SHN_UNDEF ||
1306 (symp->st_value != 0 &&
1307 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1308 *sym = (c_linker_sym_t) symp;
1309 return (0);
1310 }
1311 return (ENOENT);
1312 }
1313 }
1314
1315 return (ENOENT);
1316 }
1317
1318 static int
1319 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1320 linker_symval_t *symval)
1321 {
1322 elf_file_t ef = (elf_file_t) lf;
1323 const Elf_Sym* es = (const Elf_Sym*) sym;
1324
1325 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1326 symval->name = ef->strtab + es->st_name;
1327 symval->value = (caddr_t) ef->address + es->st_value;
1328 symval->size = es->st_size;
1329 return (0);
1330 }
1331 if (ef->symtab == ef->ddbsymtab)
1332 return (ENOENT);
1333 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1334 symval->name = ef->ddbstrtab + es->st_name;
1335 symval->value = (caddr_t) ef->address + es->st_value;
1336 symval->size = es->st_size;
1337 return (0);
1338 }
1339 return (ENOENT);
1340 }
1341
1342 static int
1343 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1344 c_linker_sym_t *sym, long *diffp)
1345 {
1346 elf_file_t ef = (elf_file_t) lf;
1347 u_long off = (uintptr_t) (void *) value;
1348 u_long diff = off;
1349 u_long st_value;
1350 const Elf_Sym* es;
1351 const Elf_Sym* best = 0;
1352 int i;
1353
1354 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1355 if (es->st_name == 0)
1356 continue;
1357 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1358 if (off >= st_value) {
1359 if (off - st_value < diff) {
1360 diff = off - st_value;
1361 best = es;
1362 if (diff == 0)
1363 break;
1364 } else if (off - st_value == diff) {
1365 best = es;
1366 }
1367 }
1368 }
1369 if (best == 0)
1370 *diffp = off;
1371 else
1372 *diffp = diff;
1373 *sym = (c_linker_sym_t) best;
1374
1375 return (0);
1376 }
1377
1378 /*
1379 * Look up a linker set on an ELF system.
1380 */
1381 static int
1382 link_elf_lookup_set(linker_file_t lf, const char *name,
1383 void ***startp, void ***stopp, int *countp)
1384 {
1385 c_linker_sym_t sym;
1386 linker_symval_t symval;
1387 char *setsym;
1388 void **start, **stop;
1389 int len, error = 0, count;
1390
1391 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1392 setsym = malloc(len, M_LINKER, M_WAITOK);
1393
1394 /* get address of first entry */
1395 snprintf(setsym, len, "%s%s", "__start_set_", name);
1396 error = link_elf_lookup_symbol(lf, setsym, &sym);
1397 if (error != 0)
1398 goto out;
1399 link_elf_symbol_values(lf, sym, &symval);
1400 if (symval.value == 0) {
1401 error = ESRCH;
1402 goto out;
1403 }
1404 start = (void **)symval.value;
1405
1406 /* get address of last entry */
1407 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1408 error = link_elf_lookup_symbol(lf, setsym, &sym);
1409 if (error != 0)
1410 goto out;
1411 link_elf_symbol_values(lf, sym, &symval);
1412 if (symval.value == 0) {
1413 error = ESRCH;
1414 goto out;
1415 }
1416 stop = (void **)symval.value;
1417
1418 /* and the number of entries */
1419 count = stop - start;
1420
1421 /* and copy out */
1422 if (startp != NULL)
1423 *startp = start;
1424 if (stopp != NULL)
1425 *stopp = stop;
1426 if (countp != NULL)
1427 *countp = count;
1428
1429 out:
1430 free(setsym, M_LINKER);
1431 return (error);
1432 }
1433
1434 static int
1435 link_elf_each_function_name(linker_file_t file,
1436 int (*callback)(const char *, void *), void *opaque)
1437 {
1438 elf_file_t ef = (elf_file_t)file;
1439 const Elf_Sym *symp;
1440 int i, error;
1441
1442 /* Exhaustive search */
1443 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1444 if (symp->st_value != 0 &&
1445 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1446 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1447 if (error != 0)
1448 return (error);
1449 }
1450 }
1451 return (0);
1452 }
1453
1454 static int
1455 link_elf_each_function_nameval(linker_file_t file,
1456 linker_function_nameval_callback_t callback, void *opaque)
1457 {
1458 linker_symval_t symval;
1459 elf_file_t ef = (elf_file_t)file;
1460 const Elf_Sym* symp;
1461 int i, error;
1462
1463 /* Exhaustive search */
1464 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1465 if (symp->st_value != 0 &&
1466 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1467 error = link_elf_symbol_values(file,
1468 (c_linker_sym_t) symp, &symval);
1469 if (error != 0)
1470 return (error);
1471 error = callback(file, i, &symval, opaque);
1472 if (error != 0)
1473 return (error);
1474 }
1475 }
1476 return (0);
1477 }
1478
1479 #ifdef __ia64__
1480 /*
1481 * Each KLD has its own GP. The GP value for each load module is given by
1482 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1483 * don't have direct access to the ELF file structure. The link_elf_get_gp()
1484 * function returns the GP given a pointer to a generic linker file struct.
1485 */
1486 Elf_Addr
1487 link_elf_get_gp(linker_file_t lf)
1488 {
1489 elf_file_t ef = (elf_file_t)lf;
1490 return ((Elf_Addr)ef->got);
1491 }
1492 #endif
1493
1494 const Elf_Sym *
1495 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1496 {
1497 elf_file_t ef = (elf_file_t)lf;
1498
1499 if (symidx >= ef->nchains)
1500 return (NULL);
1501 return (ef->symtab + symidx);
1502 }
1503
1504 const char *
1505 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1506 {
1507 elf_file_t ef = (elf_file_t)lf;
1508 const Elf_Sym *sym;
1509
1510 if (symidx >= ef->nchains)
1511 return (NULL);
1512 sym = ef->symtab + symidx;
1513 return (ef->strtab + sym->st_name);
1514 }
1515
1516 /*
1517 * Symbol lookup function that can be used when the symbol index is known (ie
1518 * in relocations). It uses the symbol index instead of doing a fully fledged
1519 * hash table based lookup when such is valid. For example for local symbols.
1520 * This is not only more efficient, it's also more correct. It's not always
1521 * the case that the symbol can be found through the hash table.
1522 */
1523 static Elf_Addr
1524 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1525 {
1526 elf_file_t ef = (elf_file_t)lf;
1527 const Elf_Sym *sym;
1528 const char *symbol;
1529 Elf_Addr addr, start, base;
1530
1531 /* Don't even try to lookup the symbol if the index is bogus. */
1532 if (symidx >= ef->nchains)
1533 return (0);
1534
1535 sym = ef->symtab + symidx;
1536
1537 /*
1538 * Don't do a full lookup when the symbol is local. It may even
1539 * fail because it may not be found through the hash table.
1540 */
1541 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1542 /* Force lookup failure when we have an insanity. */
1543 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1544 return (0);
1545 return ((Elf_Addr)ef->address + sym->st_value);
1546 }
1547
1548 /*
1549 * XXX we can avoid doing a hash table based lookup for global
1550 * symbols as well. This however is not always valid, so we'll
1551 * just do it the hard way for now. Performance tweaks can
1552 * always be added.
1553 */
1554
1555 symbol = ef->strtab + sym->st_name;
1556
1557 /* Force a lookup failure if the symbol name is bogus. */
1558 if (*symbol == 0)
1559 return (0);
1560
1561 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1562
1563 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1564 addr = addr - start + base;
1565 #ifdef VIMAGE
1566 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1567 addr = addr - start + base;
1568 #endif
1569 return addr;
1570 }
1571
1572 static void
1573 link_elf_reloc_local(linker_file_t lf)
1574 {
1575 const Elf_Rel *rellim;
1576 const Elf_Rel *rel;
1577 const Elf_Rela *relalim;
1578 const Elf_Rela *rela;
1579 elf_file_t ef = (elf_file_t)lf;
1580
1581 /* Perform relocations without addend if there are any: */
1582 if ((rel = ef->rel) != NULL) {
1583 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1584 while (rel < rellim) {
1585 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1586 ELF_RELOC_REL, elf_lookup);
1587 rel++;
1588 }
1589 }
1590
1591 /* Perform relocations with addend if there are any: */
1592 if ((rela = ef->rela) != NULL) {
1593 relalim = (const Elf_Rela *)
1594 ((const char *)ef->rela + ef->relasize);
1595 while (rela < relalim) {
1596 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1597 ELF_RELOC_RELA, elf_lookup);
1598 rela++;
1599 }
1600 }
1601 }
1602
1603 static long
1604 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1605 {
1606 elf_file_t ef = (elf_file_t)lf;
1607
1608 *symtab = ef->ddbsymtab;
1609
1610 if (*symtab == NULL)
1611 return (0);
1612
1613 return (ef->ddbsymcnt);
1614 }
1615
1616 static long
1617 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1618 {
1619 elf_file_t ef = (elf_file_t)lf;
1620
1621 *strtab = ef->ddbstrtab;
1622
1623 if (*strtab == NULL)
1624 return (0);
1625
1626 return (ef->ddbstrcnt);
1627 }
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