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 ssize_t resid;
745 int flags;
746 elf_file_t ef;
747 linker_file_t lf;
748 Elf_Shdr *shdr;
749 int symtabindex;
750 int symstrindex;
751 int symcnt;
752 int strcnt;
753 int vfslocked;
754
755 shdr = NULL;
756 lf = NULL;
757
758 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
759 flags = FREAD;
760 error = vn_open(&nd, &flags, 0, NULL);
761 if (error != 0)
762 return (error);
763 vfslocked = NDHASGIANT(&nd);
764 NDFREE(&nd, NDF_ONLY_PNBUF);
765 if (nd.ni_vp->v_type != VREG) {
766 error = ENOEXEC;
767 firstpage = NULL;
768 goto out;
769 }
770 #ifdef MAC
771 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
772 if (error != 0) {
773 firstpage = NULL;
774 goto out;
775 }
776 #endif
777
778 /*
779 * Read the elf header from the file.
780 */
781 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
782 hdr = (Elf_Ehdr *)firstpage;
783 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
784 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
785 &resid, td);
786 nbytes = PAGE_SIZE - resid;
787 if (error != 0)
788 goto out;
789
790 if (!IS_ELF(*hdr)) {
791 error = ENOEXEC;
792 goto out;
793 }
794
795 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
796 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
797 link_elf_error(filename, "Unsupported file layout");
798 error = ENOEXEC;
799 goto out;
800 }
801 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
802 hdr->e_version != EV_CURRENT) {
803 link_elf_error(filename, "Unsupported file version");
804 error = ENOEXEC;
805 goto out;
806 }
807 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
808 error = ENOSYS;
809 goto out;
810 }
811 if (hdr->e_machine != ELF_TARG_MACH) {
812 link_elf_error(filename, "Unsupported machine");
813 error = ENOEXEC;
814 goto out;
815 }
816
817 /*
818 * We rely on the program header being in the first page.
819 * This is not strictly required by the ABI specification, but
820 * it seems to always true in practice. And, it simplifies
821 * things considerably.
822 */
823 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
824 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
825 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
826 link_elf_error(filename, "Unreadable program headers");
827
828 /*
829 * Scan the program header entries, and save key information.
830 *
831 * We rely on there being exactly two load segments, text and data,
832 * in that order.
833 */
834 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
835 phlimit = phdr + hdr->e_phnum;
836 nsegs = 0;
837 phdyn = NULL;
838 phphdr = NULL;
839 while (phdr < phlimit) {
840 switch (phdr->p_type) {
841 case PT_LOAD:
842 if (nsegs == MAXSEGS) {
843 link_elf_error(filename, "Too many sections");
844 error = ENOEXEC;
845 goto out;
846 }
847 /*
848 * XXX: We just trust they come in right order ??
849 */
850 segs[nsegs] = phdr;
851 ++nsegs;
852 break;
853
854 case PT_PHDR:
855 phphdr = phdr;
856 break;
857
858 case PT_DYNAMIC:
859 phdyn = phdr;
860 break;
861
862 case PT_INTERP:
863 error = ENOSYS;
864 goto out;
865 }
866
867 ++phdr;
868 }
869 if (phdyn == NULL) {
870 link_elf_error(filename, "Object is not dynamically-linked");
871 error = ENOEXEC;
872 goto out;
873 }
874 if (nsegs == 0) {
875 link_elf_error(filename, "No sections");
876 error = ENOEXEC;
877 goto out;
878 }
879
880 /*
881 * Allocate the entire address space of the object, to stake
882 * out our contiguous region, and to establish the base
883 * address for relocation.
884 */
885 base_offset = trunc_page(segs[0]->p_offset);
886 base_vaddr = trunc_page(segs[0]->p_vaddr);
887 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
888 segs[nsegs - 1]->p_memsz);
889 mapsize = base_vlimit - base_vaddr;
890
891 lf = linker_make_file(filename, &link_elf_class);
892 if (lf == NULL) {
893 error = ENOMEM;
894 goto out;
895 }
896
897 ef = (elf_file_t) lf;
898 #ifdef SPARSE_MAPPING
899 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
900 if (ef->object == NULL) {
901 error = ENOMEM;
902 goto out;
903 }
904 ef->address = (caddr_t) vm_map_min(kernel_map);
905 error = vm_map_find(kernel_map, ef->object, 0,
906 (vm_offset_t *) &ef->address, mapsize, 1,
907 VM_PROT_ALL, VM_PROT_ALL, 0);
908 if (error != 0) {
909 vm_object_deallocate(ef->object);
910 ef->object = 0;
911 goto out;
912 }
913 #else
914 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
915 #endif
916 mapbase = ef->address;
917
918 /*
919 * Read the text and data sections and zero the bss.
920 */
921 for (i = 0; i < nsegs; i++) {
922 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
923 error = vn_rdwr(UIO_READ, nd.ni_vp,
924 segbase, segs[i]->p_filesz, segs[i]->p_offset,
925 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
926 &resid, td);
927 if (error != 0)
928 goto out;
929 bzero(segbase + segs[i]->p_filesz,
930 segs[i]->p_memsz - segs[i]->p_filesz);
931
932 #ifdef SPARSE_MAPPING
933 /*
934 * Wire down the pages
935 */
936 error = vm_map_wire(kernel_map,
937 (vm_offset_t) segbase,
938 (vm_offset_t) segbase + segs[i]->p_memsz,
939 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
940 if (error != KERN_SUCCESS) {
941 error = ENOMEM;
942 goto out;
943 }
944 #endif
945 }
946
947 #ifdef GPROF
948 /* Update profiling information with the new text segment. */
949 mtx_lock(&Giant);
950 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
951 segs[0]->p_memsz));
952 mtx_unlock(&Giant);
953 #endif
954
955 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
956
957 lf->address = ef->address;
958 lf->size = mapsize;
959
960 error = parse_dynamic(ef);
961 if (error != 0)
962 goto out;
963 error = parse_dpcpu(ef);
964 if (error != 0)
965 goto out;
966 #ifdef VIMAGE
967 error = parse_vnet(ef);
968 if (error != 0)
969 goto out;
970 #endif
971 link_elf_reloc_local(lf);
972
973 VOP_UNLOCK(nd.ni_vp, 0);
974 error = linker_load_dependencies(lf);
975 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
976 if (error != 0)
977 goto out;
978 #if 0 /* this will be more trouble than it's worth for now */
979 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
980 if (dp->d_tag != DT_NEEDED)
981 continue;
982 modname = ef->strtab + dp->d_un.d_val;
983 error = linker_load_module(modname, lf);
984 if (error != 0)
985 goto out;
986 }
987 #endif
988 error = relocate_file(ef);
989 if (error != 0)
990 goto out;
991
992 /*
993 * Try and load the symbol table if it's present. (you can
994 * strip it!)
995 */
996 nbytes = hdr->e_shnum * hdr->e_shentsize;
997 if (nbytes == 0 || hdr->e_shoff == 0)
998 goto nosyms;
999 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1000 error = vn_rdwr(UIO_READ, nd.ni_vp,
1001 (caddr_t)shdr, nbytes, hdr->e_shoff,
1002 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1003 &resid, td);
1004 if (error != 0)
1005 goto out;
1006 symtabindex = -1;
1007 symstrindex = -1;
1008 for (i = 0; i < hdr->e_shnum; i++) {
1009 if (shdr[i].sh_type == SHT_SYMTAB) {
1010 symtabindex = i;
1011 symstrindex = shdr[i].sh_link;
1012 }
1013 }
1014 if (symtabindex < 0 || symstrindex < 0)
1015 goto nosyms;
1016
1017 symcnt = shdr[symtabindex].sh_size;
1018 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1019 strcnt = shdr[symstrindex].sh_size;
1020 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1021
1022 error = vn_rdwr(UIO_READ, nd.ni_vp,
1023 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1024 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1025 &resid, td);
1026 if (error != 0)
1027 goto out;
1028 error = vn_rdwr(UIO_READ, nd.ni_vp,
1029 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1030 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1031 &resid, td);
1032 if (error != 0)
1033 goto out;
1034
1035 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1036 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1037 ef->ddbstrcnt = strcnt;
1038 ef->ddbstrtab = ef->strbase;
1039
1040 nosyms:
1041 error = link_elf_link_common_finish(lf);
1042 if (error != 0)
1043 goto out;
1044
1045 *result = lf;
1046
1047 out:
1048 VOP_UNLOCK(nd.ni_vp, 0);
1049 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1050 VFS_UNLOCK_GIANT(vfslocked);
1051 if (error != 0 && lf != NULL)
1052 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1053 if (shdr != NULL)
1054 free(shdr, M_LINKER);
1055 if (firstpage != NULL)
1056 free(firstpage, M_LINKER);
1057
1058 return (error);
1059 }
1060
1061 Elf_Addr
1062 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1063 {
1064 elf_file_t ef;
1065
1066 ef = (elf_file_t)lf;
1067 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1068 return ((x - ef->pcpu_start) + ef->pcpu_base);
1069 #ifdef VIMAGE
1070 if (x >= ef->vnet_start && x < ef->vnet_stop)
1071 return ((x - ef->vnet_start) + ef->vnet_base);
1072 #endif
1073 return (x);
1074 }
1075
1076
1077 static void
1078 link_elf_unload_file(linker_file_t file)
1079 {
1080 elf_file_t ef = (elf_file_t) file;
1081
1082 if (ef->pcpu_base != 0) {
1083 dpcpu_free((void *)ef->pcpu_base,
1084 ef->pcpu_stop - ef->pcpu_start);
1085 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1086 }
1087 #ifdef VIMAGE
1088 if (ef->vnet_base != 0) {
1089 vnet_data_free((void *)ef->vnet_base,
1090 ef->vnet_stop - ef->vnet_start);
1091 elf_set_delete(&set_vnet_list, ef->vnet_start);
1092 }
1093 #endif
1094 #ifdef GDB
1095 if (ef->gdb.l_ld != NULL) {
1096 GDB_STATE(RT_DELETE);
1097 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1098 link_elf_delete_gdb(&ef->gdb);
1099 GDB_STATE(RT_CONSISTENT);
1100 }
1101 #endif
1102
1103 /* Notify MD code that a module is being unloaded. */
1104 elf_cpu_unload_file(file);
1105
1106 if (ef->preloaded) {
1107 link_elf_unload_preload(file);
1108 return;
1109 }
1110
1111 #ifdef SPARSE_MAPPING
1112 if (ef->object != NULL) {
1113 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1114 (vm_offset_t) ef->address
1115 + (ef->object->size << PAGE_SHIFT));
1116 }
1117 #else
1118 if (ef->address != NULL)
1119 free(ef->address, M_LINKER);
1120 #endif
1121 if (ef->symbase != NULL)
1122 free(ef->symbase, M_LINKER);
1123 if (ef->strbase != NULL)
1124 free(ef->strbase, M_LINKER);
1125 if (ef->ctftab != NULL)
1126 free(ef->ctftab, M_LINKER);
1127 if (ef->ctfoff != NULL)
1128 free(ef->ctfoff, M_LINKER);
1129 if (ef->typoff != NULL)
1130 free(ef->typoff, M_LINKER);
1131 }
1132
1133 static void
1134 link_elf_unload_preload(linker_file_t file)
1135 {
1136 if (file->filename != NULL)
1137 preload_delete_name(file->filename);
1138 }
1139
1140 static const char *
1141 symbol_name(elf_file_t ef, Elf_Size r_info)
1142 {
1143 const Elf_Sym *ref;
1144
1145 if (ELF_R_SYM(r_info)) {
1146 ref = ef->symtab + ELF_R_SYM(r_info);
1147 return (ef->strtab + ref->st_name);
1148 }
1149 return (NULL);
1150 }
1151
1152 static int
1153 relocate_file(elf_file_t ef)
1154 {
1155 const Elf_Rel *rellim;
1156 const Elf_Rel *rel;
1157 const Elf_Rela *relalim;
1158 const Elf_Rela *rela;
1159 const char *symname;
1160
1161 /* Perform relocations without addend if there are any: */
1162 rel = ef->rel;
1163 if (rel != NULL) {
1164 rellim = (const Elf_Rel *)
1165 ((const char *)ef->rel + ef->relsize);
1166 while (rel < rellim) {
1167 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1168 ELF_RELOC_REL, elf_lookup)) {
1169 symname = symbol_name(ef, rel->r_info);
1170 printf("link_elf: symbol %s undefined\n", symname);
1171 return (ENOENT);
1172 }
1173 rel++;
1174 }
1175 }
1176
1177 /* Perform relocations with addend if there are any: */
1178 rela = ef->rela;
1179 if (rela != NULL) {
1180 relalim = (const Elf_Rela *)
1181 ((const char *)ef->rela + ef->relasize);
1182 while (rela < relalim) {
1183 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1184 ELF_RELOC_RELA, elf_lookup)) {
1185 symname = symbol_name(ef, rela->r_info);
1186 printf("link_elf: symbol %s undefined\n",
1187 symname);
1188 return (ENOENT);
1189 }
1190 rela++;
1191 }
1192 }
1193
1194 /* Perform PLT relocations without addend if there are any: */
1195 rel = ef->pltrel;
1196 if (rel != NULL) {
1197 rellim = (const Elf_Rel *)
1198 ((const char *)ef->pltrel + ef->pltrelsize);
1199 while (rel < rellim) {
1200 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1201 ELF_RELOC_REL, elf_lookup)) {
1202 symname = symbol_name(ef, rel->r_info);
1203 printf("link_elf: symbol %s undefined\n",
1204 symname);
1205 return (ENOENT);
1206 }
1207 rel++;
1208 }
1209 }
1210
1211 /* Perform relocations with addend if there are any: */
1212 rela = ef->pltrela;
1213 if (rela != NULL) {
1214 relalim = (const Elf_Rela *)
1215 ((const char *)ef->pltrela + ef->pltrelasize);
1216 while (rela < relalim) {
1217 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1218 ELF_RELOC_RELA, elf_lookup)) {
1219 symname = symbol_name(ef, rela->r_info);
1220 printf("link_elf: symbol %s undefined\n",
1221 symname);
1222 return (ENOENT);
1223 }
1224 rela++;
1225 }
1226 }
1227
1228 return (0);
1229 }
1230
1231 /*
1232 * Hash function for symbol table lookup. Don't even think about changing
1233 * this. It is specified by the System V ABI.
1234 */
1235 static unsigned long
1236 elf_hash(const char *name)
1237 {
1238 const unsigned char *p = (const unsigned char *) name;
1239 unsigned long h = 0;
1240 unsigned long g;
1241
1242 while (*p != '\0') {
1243 h = (h << 4) + *p++;
1244 if ((g = h & 0xf0000000) != 0)
1245 h ^= g >> 24;
1246 h &= ~g;
1247 }
1248 return (h);
1249 }
1250
1251 static int
1252 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1253 {
1254 elf_file_t ef = (elf_file_t) lf;
1255 unsigned long symnum;
1256 const Elf_Sym* symp;
1257 const char *strp;
1258 unsigned long hash;
1259 int i;
1260
1261 /* If we don't have a hash, bail. */
1262 if (ef->buckets == NULL || ef->nbuckets == 0) {
1263 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1264 return (ENOENT);
1265 }
1266
1267 /* First, search hashed global symbols */
1268 hash = elf_hash(name);
1269 symnum = ef->buckets[hash % ef->nbuckets];
1270
1271 while (symnum != STN_UNDEF) {
1272 if (symnum >= ef->nchains) {
1273 printf("%s: corrupt symbol table\n", __func__);
1274 return (ENOENT);
1275 }
1276
1277 symp = ef->symtab + symnum;
1278 if (symp->st_name == 0) {
1279 printf("%s: corrupt symbol table\n", __func__);
1280 return (ENOENT);
1281 }
1282
1283 strp = ef->strtab + symp->st_name;
1284
1285 if (strcmp(name, strp) == 0) {
1286 if (symp->st_shndx != SHN_UNDEF ||
1287 (symp->st_value != 0 &&
1288 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1289 *sym = (c_linker_sym_t) symp;
1290 return (0);
1291 }
1292 return (ENOENT);
1293 }
1294
1295 symnum = ef->chains[symnum];
1296 }
1297
1298 /* If we have not found it, look at the full table (if loaded) */
1299 if (ef->symtab == ef->ddbsymtab)
1300 return (ENOENT);
1301
1302 /* Exhaustive search */
1303 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1304 strp = ef->ddbstrtab + symp->st_name;
1305 if (strcmp(name, strp) == 0) {
1306 if (symp->st_shndx != SHN_UNDEF ||
1307 (symp->st_value != 0 &&
1308 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1309 *sym = (c_linker_sym_t) symp;
1310 return (0);
1311 }
1312 return (ENOENT);
1313 }
1314 }
1315
1316 return (ENOENT);
1317 }
1318
1319 static int
1320 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1321 linker_symval_t *symval)
1322 {
1323 elf_file_t ef = (elf_file_t) lf;
1324 const Elf_Sym* es = (const Elf_Sym*) sym;
1325
1326 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1327 symval->name = ef->strtab + es->st_name;
1328 symval->value = (caddr_t) ef->address + es->st_value;
1329 symval->size = es->st_size;
1330 return (0);
1331 }
1332 if (ef->symtab == ef->ddbsymtab)
1333 return (ENOENT);
1334 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1335 symval->name = ef->ddbstrtab + es->st_name;
1336 symval->value = (caddr_t) ef->address + es->st_value;
1337 symval->size = es->st_size;
1338 return (0);
1339 }
1340 return (ENOENT);
1341 }
1342
1343 static int
1344 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1345 c_linker_sym_t *sym, long *diffp)
1346 {
1347 elf_file_t ef = (elf_file_t) lf;
1348 u_long off = (uintptr_t) (void *) value;
1349 u_long diff = off;
1350 u_long st_value;
1351 const Elf_Sym* es;
1352 const Elf_Sym* best = 0;
1353 int i;
1354
1355 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1356 if (es->st_name == 0)
1357 continue;
1358 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1359 if (off >= st_value) {
1360 if (off - st_value < diff) {
1361 diff = off - st_value;
1362 best = es;
1363 if (diff == 0)
1364 break;
1365 } else if (off - st_value == diff) {
1366 best = es;
1367 }
1368 }
1369 }
1370 if (best == 0)
1371 *diffp = off;
1372 else
1373 *diffp = diff;
1374 *sym = (c_linker_sym_t) best;
1375
1376 return (0);
1377 }
1378
1379 /*
1380 * Look up a linker set on an ELF system.
1381 */
1382 static int
1383 link_elf_lookup_set(linker_file_t lf, const char *name,
1384 void ***startp, void ***stopp, int *countp)
1385 {
1386 c_linker_sym_t sym;
1387 linker_symval_t symval;
1388 char *setsym;
1389 void **start, **stop;
1390 int len, error = 0, count;
1391
1392 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1393 setsym = malloc(len, M_LINKER, M_WAITOK);
1394
1395 /* get address of first entry */
1396 snprintf(setsym, len, "%s%s", "__start_set_", name);
1397 error = link_elf_lookup_symbol(lf, setsym, &sym);
1398 if (error != 0)
1399 goto out;
1400 link_elf_symbol_values(lf, sym, &symval);
1401 if (symval.value == 0) {
1402 error = ESRCH;
1403 goto out;
1404 }
1405 start = (void **)symval.value;
1406
1407 /* get address of last entry */
1408 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1409 error = link_elf_lookup_symbol(lf, setsym, &sym);
1410 if (error != 0)
1411 goto out;
1412 link_elf_symbol_values(lf, sym, &symval);
1413 if (symval.value == 0) {
1414 error = ESRCH;
1415 goto out;
1416 }
1417 stop = (void **)symval.value;
1418
1419 /* and the number of entries */
1420 count = stop - start;
1421
1422 /* and copy out */
1423 if (startp != NULL)
1424 *startp = start;
1425 if (stopp != NULL)
1426 *stopp = stop;
1427 if (countp != NULL)
1428 *countp = count;
1429
1430 out:
1431 free(setsym, M_LINKER);
1432 return (error);
1433 }
1434
1435 static int
1436 link_elf_each_function_name(linker_file_t file,
1437 int (*callback)(const char *, void *), void *opaque)
1438 {
1439 elf_file_t ef = (elf_file_t)file;
1440 const Elf_Sym *symp;
1441 int i, error;
1442
1443 /* Exhaustive search */
1444 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1445 if (symp->st_value != 0 &&
1446 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1447 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1448 if (error != 0)
1449 return (error);
1450 }
1451 }
1452 return (0);
1453 }
1454
1455 static int
1456 link_elf_each_function_nameval(linker_file_t file,
1457 linker_function_nameval_callback_t callback, void *opaque)
1458 {
1459 linker_symval_t symval;
1460 elf_file_t ef = (elf_file_t)file;
1461 const Elf_Sym* symp;
1462 int i, error;
1463
1464 /* Exhaustive search */
1465 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1466 if (symp->st_value != 0 &&
1467 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1468 error = link_elf_symbol_values(file,
1469 (c_linker_sym_t) symp, &symval);
1470 if (error != 0)
1471 return (error);
1472 error = callback(file, i, &symval, opaque);
1473 if (error != 0)
1474 return (error);
1475 }
1476 }
1477 return (0);
1478 }
1479
1480 #ifdef __ia64__
1481 /*
1482 * Each KLD has its own GP. The GP value for each load module is given by
1483 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1484 * don't have direct access to the ELF file structure. The link_elf_get_gp()
1485 * function returns the GP given a pointer to a generic linker file struct.
1486 */
1487 Elf_Addr
1488 link_elf_get_gp(linker_file_t lf)
1489 {
1490 elf_file_t ef = (elf_file_t)lf;
1491 return ((Elf_Addr)ef->got);
1492 }
1493 #endif
1494
1495 const Elf_Sym *
1496 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1497 {
1498 elf_file_t ef = (elf_file_t)lf;
1499
1500 if (symidx >= ef->nchains)
1501 return (NULL);
1502 return (ef->symtab + symidx);
1503 }
1504
1505 const char *
1506 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1507 {
1508 elf_file_t ef = (elf_file_t)lf;
1509 const Elf_Sym *sym;
1510
1511 if (symidx >= ef->nchains)
1512 return (NULL);
1513 sym = ef->symtab + symidx;
1514 return (ef->strtab + sym->st_name);
1515 }
1516
1517 /*
1518 * Symbol lookup function that can be used when the symbol index is known (ie
1519 * in relocations). It uses the symbol index instead of doing a fully fledged
1520 * hash table based lookup when such is valid. For example for local symbols.
1521 * This is not only more efficient, it's also more correct. It's not always
1522 * the case that the symbol can be found through the hash table.
1523 */
1524 static Elf_Addr
1525 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1526 {
1527 elf_file_t ef = (elf_file_t)lf;
1528 const Elf_Sym *sym;
1529 const char *symbol;
1530 Elf_Addr addr, start, base;
1531
1532 /* Don't even try to lookup the symbol if the index is bogus. */
1533 if (symidx >= ef->nchains)
1534 return (0);
1535
1536 sym = ef->symtab + symidx;
1537
1538 /*
1539 * Don't do a full lookup when the symbol is local. It may even
1540 * fail because it may not be found through the hash table.
1541 */
1542 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1543 /* Force lookup failure when we have an insanity. */
1544 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1545 return (0);
1546 return ((Elf_Addr)ef->address + sym->st_value);
1547 }
1548
1549 /*
1550 * XXX we can avoid doing a hash table based lookup for global
1551 * symbols as well. This however is not always valid, so we'll
1552 * just do it the hard way for now. Performance tweaks can
1553 * always be added.
1554 */
1555
1556 symbol = ef->strtab + sym->st_name;
1557
1558 /* Force a lookup failure if the symbol name is bogus. */
1559 if (*symbol == 0)
1560 return (0);
1561
1562 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1563
1564 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1565 addr = addr - start + base;
1566 #ifdef VIMAGE
1567 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1568 addr = addr - start + base;
1569 #endif
1570 return addr;
1571 }
1572
1573 static void
1574 link_elf_reloc_local(linker_file_t lf)
1575 {
1576 const Elf_Rel *rellim;
1577 const Elf_Rel *rel;
1578 const Elf_Rela *relalim;
1579 const Elf_Rela *rela;
1580 elf_file_t ef = (elf_file_t)lf;
1581
1582 /* Perform relocations without addend if there are any: */
1583 if ((rel = ef->rel) != NULL) {
1584 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1585 while (rel < rellim) {
1586 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1587 ELF_RELOC_REL, elf_lookup);
1588 rel++;
1589 }
1590 }
1591
1592 /* Perform relocations with addend if there are any: */
1593 if ((rela = ef->rela) != NULL) {
1594 relalim = (const Elf_Rela *)
1595 ((const char *)ef->rela + ef->relasize);
1596 while (rela < relalim) {
1597 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1598 ELF_RELOC_RELA, elf_lookup);
1599 rela++;
1600 }
1601 }
1602 }
1603
1604 static long
1605 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1606 {
1607 elf_file_t ef = (elf_file_t)lf;
1608
1609 *symtab = ef->ddbsymtab;
1610
1611 if (*symtab == NULL)
1612 return (0);
1613
1614 return (ef->ddbsymcnt);
1615 }
1616
1617 static long
1618 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1619 {
1620 elf_file_t ef = (elf_file_t)lf;
1621
1622 *strtab = ef->ddbstrtab;
1623
1624 if (*strtab == NULL)
1625 return (0);
1626
1627 return (ef->ddbstrcnt);
1628 }
Cache object: f7c0ffec18b92034c270396e42e97a72
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