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/11.0/sys/kern/link_elf.c 298069 2016-04-15 16:10:11Z pfg $");
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 <sys/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 int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
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 /*
321 * The kernel symbol table starts here.
322 */
323 extern struct _dynamic _DYNAMIC;
324
325 static void
326 link_elf_error(const char *filename, const char *s)
327 {
328 if (filename == NULL)
329 printf("kldload: %s\n", s);
330 else
331 printf("kldload: %s: %s\n", filename, s);
332 }
333
334 static void
335 link_elf_invoke_ctors(caddr_t addr, size_t size)
336 {
337 void (**ctor)(void);
338 size_t i, cnt;
339
340 if (addr == NULL || size == 0)
341 return;
342 cnt = size / sizeof(*ctor);
343 ctor = (void *)addr;
344 for (i = 0; i < cnt; i++) {
345 if (ctor[i] != NULL)
346 (*ctor[i])();
347 }
348 }
349
350 /*
351 * Actions performed after linking/loading both the preloaded kernel and any
352 * modules; whether preloaded or dynamicly loaded.
353 */
354 static int
355 link_elf_link_common_finish(linker_file_t lf)
356 {
357 #ifdef GDB
358 elf_file_t ef = (elf_file_t)lf;
359 char *newfilename;
360 #endif
361 int error;
362
363 /* Notify MD code that a module is being loaded. */
364 error = elf_cpu_load_file(lf);
365 if (error != 0)
366 return (error);
367
368 #ifdef GDB
369 GDB_STATE(RT_ADD);
370 ef->gdb.l_addr = lf->address;
371 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
372 strcpy(newfilename, lf->filename);
373 ef->gdb.l_name = newfilename;
374 ef->gdb.l_ld = ef->dynamic;
375 link_elf_add_gdb(&ef->gdb);
376 GDB_STATE(RT_CONSISTENT);
377 #endif
378
379 /* Invoke .ctors */
380 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
381 return (0);
382 }
383
384 extern vm_offset_t __startkernel;
385
386 static void
387 link_elf_init(void* arg)
388 {
389 Elf_Dyn *dp;
390 Elf_Addr *ctors_addrp;
391 Elf_Size *ctors_sizep;
392 caddr_t modptr, baseptr, sizeptr;
393 elf_file_t ef;
394 char *modname;
395
396 linker_add_class(&link_elf_class);
397
398 dp = (Elf_Dyn *)&_DYNAMIC;
399 modname = NULL;
400 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
401 if (modptr == NULL)
402 modptr = preload_search_by_type("elf kernel");
403 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
404 if (modname == NULL)
405 modname = "kernel";
406 linker_kernel_file = linker_make_file(modname, &link_elf_class);
407 if (linker_kernel_file == NULL)
408 panic("%s: Can't create linker structures for kernel",
409 __func__);
410
411 ef = (elf_file_t) linker_kernel_file;
412 ef->preloaded = 1;
413 #ifdef __powerpc__
414 ef->address = (caddr_t) (__startkernel - KERNBASE);
415 #else
416 ef->address = 0;
417 #endif
418 #ifdef SPARSE_MAPPING
419 ef->object = 0;
420 #endif
421 ef->dynamic = dp;
422
423 if (dp != NULL)
424 parse_dynamic(ef);
425 linker_kernel_file->address += KERNBASE;
426 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
427
428 if (modptr != NULL) {
429 ef->modptr = modptr;
430 baseptr = preload_search_info(modptr, MODINFO_ADDR);
431 if (baseptr != NULL)
432 linker_kernel_file->address = *(caddr_t *)baseptr;
433 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
434 if (sizeptr != NULL)
435 linker_kernel_file->size = *(size_t *)sizeptr;
436 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
437 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
438 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
439 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
440 if (ctors_addrp != NULL && ctors_sizep != NULL) {
441 linker_kernel_file->ctors_addr = ef->address +
442 *ctors_addrp;
443 linker_kernel_file->ctors_size = *ctors_sizep;
444 }
445 }
446 (void)link_elf_preload_parse_symbols(ef);
447
448 #ifdef GDB
449 r_debug.r_map = NULL;
450 r_debug.r_brk = r_debug_state;
451 r_debug.r_state = RT_CONSISTENT;
452 #endif
453
454 (void)link_elf_link_common_finish(linker_kernel_file);
455 linker_kernel_file->flags |= LINKER_FILE_LINKED;
456 TAILQ_INIT(&set_pcpu_list);
457 #ifdef VIMAGE
458 TAILQ_INIT(&set_vnet_list);
459 #endif
460 }
461
462 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
463
464 static int
465 link_elf_preload_parse_symbols(elf_file_t ef)
466 {
467 caddr_t pointer;
468 caddr_t ssym, esym, base;
469 caddr_t strtab;
470 int strcnt;
471 Elf_Sym *symtab;
472 int symcnt;
473
474 if (ef->modptr == NULL)
475 return (0);
476 pointer = preload_search_info(ef->modptr,
477 MODINFO_METADATA | MODINFOMD_SSYM);
478 if (pointer == NULL)
479 return (0);
480 ssym = *(caddr_t *)pointer;
481 pointer = preload_search_info(ef->modptr,
482 MODINFO_METADATA | MODINFOMD_ESYM);
483 if (pointer == NULL)
484 return (0);
485 esym = *(caddr_t *)pointer;
486
487 base = ssym;
488
489 symcnt = *(long *)base;
490 base += sizeof(long);
491 symtab = (Elf_Sym *)base;
492 base += roundup(symcnt, sizeof(long));
493
494 if (base > esym || base < ssym) {
495 printf("Symbols are corrupt!\n");
496 return (EINVAL);
497 }
498
499 strcnt = *(long *)base;
500 base += sizeof(long);
501 strtab = base;
502 base += roundup(strcnt, sizeof(long));
503
504 if (base > esym || base < ssym) {
505 printf("Symbols are corrupt!\n");
506 return (EINVAL);
507 }
508
509 ef->ddbsymtab = symtab;
510 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
511 ef->ddbstrtab = strtab;
512 ef->ddbstrcnt = strcnt;
513
514 return (0);
515 }
516
517 static int
518 parse_dynamic(elf_file_t ef)
519 {
520 Elf_Dyn *dp;
521 int plttype = DT_REL;
522
523 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
524 switch (dp->d_tag) {
525 case DT_HASH:
526 {
527 /* From src/libexec/rtld-elf/rtld.c */
528 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
529 (ef->address + dp->d_un.d_ptr);
530 ef->nbuckets = hashtab[0];
531 ef->nchains = hashtab[1];
532 ef->buckets = hashtab + 2;
533 ef->chains = ef->buckets + ef->nbuckets;
534 break;
535 }
536 case DT_STRTAB:
537 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
538 break;
539 case DT_STRSZ:
540 ef->strsz = dp->d_un.d_val;
541 break;
542 case DT_SYMTAB:
543 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
544 break;
545 case DT_SYMENT:
546 if (dp->d_un.d_val != sizeof(Elf_Sym))
547 return (ENOEXEC);
548 break;
549 case DT_PLTGOT:
550 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
551 break;
552 case DT_REL:
553 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
554 break;
555 case DT_RELSZ:
556 ef->relsize = dp->d_un.d_val;
557 break;
558 case DT_RELENT:
559 if (dp->d_un.d_val != sizeof(Elf_Rel))
560 return (ENOEXEC);
561 break;
562 case DT_JMPREL:
563 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
564 break;
565 case DT_PLTRELSZ:
566 ef->pltrelsize = dp->d_un.d_val;
567 break;
568 case DT_RELA:
569 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
570 break;
571 case DT_RELASZ:
572 ef->relasize = dp->d_un.d_val;
573 break;
574 case DT_RELAENT:
575 if (dp->d_un.d_val != sizeof(Elf_Rela))
576 return (ENOEXEC);
577 break;
578 case DT_PLTREL:
579 plttype = dp->d_un.d_val;
580 if (plttype != DT_REL && plttype != DT_RELA)
581 return (ENOEXEC);
582 break;
583 #ifdef GDB
584 case DT_DEBUG:
585 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
586 break;
587 #endif
588 }
589 }
590
591 if (plttype == DT_RELA) {
592 ef->pltrela = (const Elf_Rela *)ef->pltrel;
593 ef->pltrel = NULL;
594 ef->pltrelasize = ef->pltrelsize;
595 ef->pltrelsize = 0;
596 }
597
598 ef->ddbsymtab = ef->symtab;
599 ef->ddbsymcnt = ef->nchains;
600 ef->ddbstrtab = ef->strtab;
601 ef->ddbstrcnt = ef->strsz;
602
603 return (0);
604 }
605
606 static int
607 parse_dpcpu(elf_file_t ef)
608 {
609 int count;
610 int error;
611
612 ef->pcpu_start = 0;
613 ef->pcpu_stop = 0;
614 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
615 (void ***)&ef->pcpu_stop, &count);
616 /* Error just means there is no pcpu set to relocate. */
617 if (error != 0)
618 return (0);
619 count *= sizeof(void *);
620 /*
621 * Allocate space in the primary pcpu area. Copy in our
622 * initialization from the data section and then initialize
623 * all per-cpu storage from that.
624 */
625 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
626 if (ef->pcpu_base == 0)
627 return (ENOSPC);
628 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
629 dpcpu_copy((void *)ef->pcpu_base, count);
630 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
631 ef->pcpu_base);
632
633 return (0);
634 }
635
636 #ifdef VIMAGE
637 static int
638 parse_vnet(elf_file_t ef)
639 {
640 int count;
641 int error;
642
643 ef->vnet_start = 0;
644 ef->vnet_stop = 0;
645 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
646 (void ***)&ef->vnet_stop, &count);
647 /* Error just means there is no vnet data set to relocate. */
648 if (error != 0)
649 return (0);
650 count *= sizeof(void *);
651 /*
652 * Allocate space in the primary vnet area. Copy in our
653 * initialization from the data section and then initialize
654 * all per-vnet storage from that.
655 */
656 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
657 if (ef->vnet_base == 0)
658 return (ENOSPC);
659 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
660 vnet_data_copy((void *)ef->vnet_base, count);
661 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
662 ef->vnet_base);
663
664 return (0);
665 }
666 #endif
667
668 static int
669 link_elf_link_preload(linker_class_t cls,
670 const char* filename, linker_file_t *result)
671 {
672 Elf_Addr *ctors_addrp;
673 Elf_Size *ctors_sizep;
674 caddr_t modptr, baseptr, sizeptr, dynptr;
675 char *type;
676 elf_file_t ef;
677 linker_file_t lf;
678 int error;
679 vm_offset_t dp;
680
681 /* Look to see if we have the file preloaded */
682 modptr = preload_search_by_name(filename);
683 if (modptr == NULL)
684 return (ENOENT);
685
686 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
687 baseptr = preload_search_info(modptr, MODINFO_ADDR);
688 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
689 dynptr = preload_search_info(modptr,
690 MODINFO_METADATA | MODINFOMD_DYNAMIC);
691 if (type == NULL ||
692 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
693 strcmp(type, "elf module") != 0))
694 return (EFTYPE);
695 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
696 return (EINVAL);
697
698 lf = linker_make_file(filename, &link_elf_class);
699 if (lf == NULL)
700 return (ENOMEM);
701
702 ef = (elf_file_t) lf;
703 ef->preloaded = 1;
704 ef->modptr = modptr;
705 ef->address = *(caddr_t *)baseptr;
706 #ifdef SPARSE_MAPPING
707 ef->object = 0;
708 #endif
709 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
710 ef->dynamic = (Elf_Dyn *)dp;
711 lf->address = ef->address;
712 lf->size = *(size_t *)sizeptr;
713
714 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
715 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
716 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
717 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
718 if (ctors_addrp != NULL && ctors_sizep != NULL) {
719 lf->ctors_addr = ef->address + *ctors_addrp;
720 lf->ctors_size = *ctors_sizep;
721 }
722
723 error = parse_dynamic(ef);
724 if (error == 0)
725 error = parse_dpcpu(ef);
726 #ifdef VIMAGE
727 if (error == 0)
728 error = parse_vnet(ef);
729 #endif
730 if (error != 0) {
731 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
732 return (error);
733 }
734 link_elf_reloc_local(lf);
735 *result = lf;
736 return (0);
737 }
738
739 static int
740 link_elf_link_preload_finish(linker_file_t lf)
741 {
742 elf_file_t ef;
743 int error;
744
745 ef = (elf_file_t) lf;
746 error = relocate_file(ef);
747 if (error != 0)
748 return (error);
749 (void)link_elf_preload_parse_symbols(ef);
750
751 return (link_elf_link_common_finish(lf));
752 }
753
754 static int
755 link_elf_load_file(linker_class_t cls, const char* filename,
756 linker_file_t* result)
757 {
758 struct nameidata nd;
759 struct thread* td = curthread; /* XXX */
760 Elf_Ehdr *hdr;
761 caddr_t firstpage;
762 int nbytes, i;
763 Elf_Phdr *phdr;
764 Elf_Phdr *phlimit;
765 Elf_Phdr *segs[MAXSEGS];
766 int nsegs;
767 Elf_Phdr *phdyn;
768 Elf_Phdr *phphdr;
769 caddr_t mapbase;
770 size_t mapsize;
771 Elf_Off base_offset;
772 Elf_Addr base_vaddr;
773 Elf_Addr base_vlimit;
774 int error = 0;
775 ssize_t resid;
776 int flags;
777 elf_file_t ef;
778 linker_file_t lf;
779 Elf_Shdr *shdr;
780 int symtabindex;
781 int symstrindex;
782 int shstrindex;
783 int symcnt;
784 int strcnt;
785 char *shstrs;
786
787 shdr = NULL;
788 lf = NULL;
789 shstrs = NULL;
790
791 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
792 flags = FREAD;
793 error = vn_open(&nd, &flags, 0, NULL);
794 if (error != 0)
795 return (error);
796 NDFREE(&nd, NDF_ONLY_PNBUF);
797 if (nd.ni_vp->v_type != VREG) {
798 error = ENOEXEC;
799 firstpage = NULL;
800 goto out;
801 }
802 #ifdef MAC
803 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
804 if (error != 0) {
805 firstpage = NULL;
806 goto out;
807 }
808 #endif
809
810 /*
811 * Read the elf header from the file.
812 */
813 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
814 hdr = (Elf_Ehdr *)firstpage;
815 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
816 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
817 &resid, td);
818 nbytes = PAGE_SIZE - resid;
819 if (error != 0)
820 goto out;
821
822 if (!IS_ELF(*hdr)) {
823 error = ENOEXEC;
824 goto out;
825 }
826
827 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
828 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
829 link_elf_error(filename, "Unsupported file layout");
830 error = ENOEXEC;
831 goto out;
832 }
833 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
834 hdr->e_version != EV_CURRENT) {
835 link_elf_error(filename, "Unsupported file version");
836 error = ENOEXEC;
837 goto out;
838 }
839 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
840 error = ENOSYS;
841 goto out;
842 }
843 if (hdr->e_machine != ELF_TARG_MACH) {
844 link_elf_error(filename, "Unsupported machine");
845 error = ENOEXEC;
846 goto out;
847 }
848
849 /*
850 * We rely on the program header being in the first page.
851 * This is not strictly required by the ABI specification, but
852 * it seems to always true in practice. And, it simplifies
853 * things considerably.
854 */
855 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
856 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
857 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
858 link_elf_error(filename, "Unreadable program headers");
859
860 /*
861 * Scan the program header entries, and save key information.
862 *
863 * We rely on there being exactly two load segments, text and data,
864 * in that order.
865 */
866 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
867 phlimit = phdr + hdr->e_phnum;
868 nsegs = 0;
869 phdyn = NULL;
870 phphdr = NULL;
871 while (phdr < phlimit) {
872 switch (phdr->p_type) {
873 case PT_LOAD:
874 if (nsegs == MAXSEGS) {
875 link_elf_error(filename, "Too many sections");
876 error = ENOEXEC;
877 goto out;
878 }
879 /*
880 * XXX: We just trust they come in right order ??
881 */
882 segs[nsegs] = phdr;
883 ++nsegs;
884 break;
885
886 case PT_PHDR:
887 phphdr = phdr;
888 break;
889
890 case PT_DYNAMIC:
891 phdyn = phdr;
892 break;
893
894 case PT_INTERP:
895 error = ENOSYS;
896 goto out;
897 }
898
899 ++phdr;
900 }
901 if (phdyn == NULL) {
902 link_elf_error(filename, "Object is not dynamically-linked");
903 error = ENOEXEC;
904 goto out;
905 }
906 if (nsegs == 0) {
907 link_elf_error(filename, "No sections");
908 error = ENOEXEC;
909 goto out;
910 }
911
912 /*
913 * Allocate the entire address space of the object, to stake
914 * out our contiguous region, and to establish the base
915 * address for relocation.
916 */
917 base_offset = trunc_page(segs[0]->p_offset);
918 base_vaddr = trunc_page(segs[0]->p_vaddr);
919 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
920 segs[nsegs - 1]->p_memsz);
921 mapsize = base_vlimit - base_vaddr;
922
923 lf = linker_make_file(filename, &link_elf_class);
924 if (lf == NULL) {
925 error = ENOMEM;
926 goto out;
927 }
928
929 ef = (elf_file_t) lf;
930 #ifdef SPARSE_MAPPING
931 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
932 if (ef->object == NULL) {
933 error = ENOMEM;
934 goto out;
935 }
936 ef->address = (caddr_t) vm_map_min(kernel_map);
937 error = vm_map_find(kernel_map, ef->object, 0,
938 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE,
939 VM_PROT_ALL, VM_PROT_ALL, 0);
940 if (error != 0) {
941 vm_object_deallocate(ef->object);
942 ef->object = 0;
943 goto out;
944 }
945 #else
946 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
947 #endif
948 mapbase = ef->address;
949
950 /*
951 * Read the text and data sections and zero the bss.
952 */
953 for (i = 0; i < nsegs; i++) {
954 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
955 error = vn_rdwr(UIO_READ, nd.ni_vp,
956 segbase, segs[i]->p_filesz, segs[i]->p_offset,
957 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
958 &resid, td);
959 if (error != 0)
960 goto out;
961 bzero(segbase + segs[i]->p_filesz,
962 segs[i]->p_memsz - segs[i]->p_filesz);
963
964 #ifdef SPARSE_MAPPING
965 /*
966 * Wire down the pages
967 */
968 error = vm_map_wire(kernel_map,
969 (vm_offset_t) segbase,
970 (vm_offset_t) segbase + segs[i]->p_memsz,
971 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
972 if (error != KERN_SUCCESS) {
973 error = ENOMEM;
974 goto out;
975 }
976 #endif
977 }
978
979 #ifdef GPROF
980 /* Update profiling information with the new text segment. */
981 mtx_lock(&Giant);
982 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
983 segs[0]->p_memsz));
984 mtx_unlock(&Giant);
985 #endif
986
987 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
988
989 lf->address = ef->address;
990 lf->size = mapsize;
991
992 error = parse_dynamic(ef);
993 if (error != 0)
994 goto out;
995 error = parse_dpcpu(ef);
996 if (error != 0)
997 goto out;
998 #ifdef VIMAGE
999 error = parse_vnet(ef);
1000 if (error != 0)
1001 goto out;
1002 #endif
1003 link_elf_reloc_local(lf);
1004
1005 VOP_UNLOCK(nd.ni_vp, 0);
1006 error = linker_load_dependencies(lf);
1007 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1008 if (error != 0)
1009 goto out;
1010 error = relocate_file(ef);
1011 if (error != 0)
1012 goto out;
1013
1014 /*
1015 * Try and load the symbol table if it's present. (you can
1016 * strip it!)
1017 */
1018 nbytes = hdr->e_shnum * hdr->e_shentsize;
1019 if (nbytes == 0 || hdr->e_shoff == 0)
1020 goto nosyms;
1021 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1022 error = vn_rdwr(UIO_READ, nd.ni_vp,
1023 (caddr_t)shdr, nbytes, hdr->e_shoff,
1024 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1025 &resid, td);
1026 if (error != 0)
1027 goto out;
1028
1029 /* Read section string table */
1030 shstrindex = hdr->e_shstrndx;
1031 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1032 shdr[shstrindex].sh_size != 0) {
1033 nbytes = shdr[shstrindex].sh_size;
1034 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1035 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1036 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1037 td->td_ucred, NOCRED, &resid, td);
1038 if (error)
1039 goto out;
1040 }
1041
1042 symtabindex = -1;
1043 symstrindex = -1;
1044 for (i = 0; i < hdr->e_shnum; i++) {
1045 if (shdr[i].sh_type == SHT_SYMTAB) {
1046 symtabindex = i;
1047 symstrindex = shdr[i].sh_link;
1048 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1049 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1050 /* Record relocated address and size of .ctors. */
1051 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1052 lf->ctors_size = shdr[i].sh_size;
1053 }
1054 }
1055 if (symtabindex < 0 || symstrindex < 0)
1056 goto nosyms;
1057
1058 symcnt = shdr[symtabindex].sh_size;
1059 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1060 strcnt = shdr[symstrindex].sh_size;
1061 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1062
1063 error = vn_rdwr(UIO_READ, nd.ni_vp,
1064 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1065 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1066 &resid, td);
1067 if (error != 0)
1068 goto out;
1069 error = vn_rdwr(UIO_READ, nd.ni_vp,
1070 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1071 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1072 &resid, td);
1073 if (error != 0)
1074 goto out;
1075
1076 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1077 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1078 ef->ddbstrcnt = strcnt;
1079 ef->ddbstrtab = ef->strbase;
1080
1081 nosyms:
1082 error = link_elf_link_common_finish(lf);
1083 if (error != 0)
1084 goto out;
1085
1086 *result = lf;
1087
1088 out:
1089 VOP_UNLOCK(nd.ni_vp, 0);
1090 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1091 if (error != 0 && lf != NULL)
1092 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1093 free(shdr, M_LINKER);
1094 free(firstpage, M_LINKER);
1095 free(shstrs, M_LINKER);
1096
1097 return (error);
1098 }
1099
1100 Elf_Addr
1101 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1102 {
1103 elf_file_t ef;
1104
1105 ef = (elf_file_t)lf;
1106 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1107 return ((x - ef->pcpu_start) + ef->pcpu_base);
1108 #ifdef VIMAGE
1109 if (x >= ef->vnet_start && x < ef->vnet_stop)
1110 return ((x - ef->vnet_start) + ef->vnet_base);
1111 #endif
1112 return (x);
1113 }
1114
1115
1116 static void
1117 link_elf_unload_file(linker_file_t file)
1118 {
1119 elf_file_t ef = (elf_file_t) file;
1120
1121 if (ef->pcpu_base != 0) {
1122 dpcpu_free((void *)ef->pcpu_base,
1123 ef->pcpu_stop - ef->pcpu_start);
1124 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1125 }
1126 #ifdef VIMAGE
1127 if (ef->vnet_base != 0) {
1128 vnet_data_free((void *)ef->vnet_base,
1129 ef->vnet_stop - ef->vnet_start);
1130 elf_set_delete(&set_vnet_list, ef->vnet_start);
1131 }
1132 #endif
1133 #ifdef GDB
1134 if (ef->gdb.l_ld != NULL) {
1135 GDB_STATE(RT_DELETE);
1136 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1137 link_elf_delete_gdb(&ef->gdb);
1138 GDB_STATE(RT_CONSISTENT);
1139 }
1140 #endif
1141
1142 /* Notify MD code that a module is being unloaded. */
1143 elf_cpu_unload_file(file);
1144
1145 if (ef->preloaded) {
1146 link_elf_unload_preload(file);
1147 return;
1148 }
1149
1150 #ifdef SPARSE_MAPPING
1151 if (ef->object != NULL) {
1152 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1153 (vm_offset_t) ef->address
1154 + (ef->object->size << PAGE_SHIFT));
1155 }
1156 #else
1157 free(ef->address, M_LINKER);
1158 #endif
1159 free(ef->symbase, M_LINKER);
1160 free(ef->strbase, M_LINKER);
1161 free(ef->ctftab, M_LINKER);
1162 free(ef->ctfoff, M_LINKER);
1163 free(ef->typoff, M_LINKER);
1164 }
1165
1166 static void
1167 link_elf_unload_preload(linker_file_t file)
1168 {
1169 if (file->filename != NULL)
1170 preload_delete_name(file->filename);
1171 }
1172
1173 static const char *
1174 symbol_name(elf_file_t ef, Elf_Size r_info)
1175 {
1176 const Elf_Sym *ref;
1177
1178 if (ELF_R_SYM(r_info)) {
1179 ref = ef->symtab + ELF_R_SYM(r_info);
1180 return (ef->strtab + ref->st_name);
1181 }
1182 return (NULL);
1183 }
1184
1185 static int
1186 relocate_file(elf_file_t ef)
1187 {
1188 const Elf_Rel *rellim;
1189 const Elf_Rel *rel;
1190 const Elf_Rela *relalim;
1191 const Elf_Rela *rela;
1192 const char *symname;
1193
1194 /* Perform relocations without addend if there are any: */
1195 rel = ef->rel;
1196 if (rel != NULL) {
1197 rellim = (const Elf_Rel *)
1198 ((const char *)ef->rel + ef->relsize);
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", symname);
1204 return (ENOENT);
1205 }
1206 rel++;
1207 }
1208 }
1209
1210 /* Perform relocations with addend if there are any: */
1211 rela = ef->rela;
1212 if (rela != NULL) {
1213 relalim = (const Elf_Rela *)
1214 ((const char *)ef->rela + ef->relasize);
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 /* Perform PLT relocations without addend if there are any: */
1228 rel = ef->pltrel;
1229 if (rel != NULL) {
1230 rellim = (const Elf_Rel *)
1231 ((const char *)ef->pltrel + ef->pltrelsize);
1232 while (rel < rellim) {
1233 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1234 ELF_RELOC_REL, elf_lookup)) {
1235 symname = symbol_name(ef, rel->r_info);
1236 printf("link_elf: symbol %s undefined\n",
1237 symname);
1238 return (ENOENT);
1239 }
1240 rel++;
1241 }
1242 }
1243
1244 /* Perform relocations with addend if there are any: */
1245 rela = ef->pltrela;
1246 if (rela != NULL) {
1247 relalim = (const Elf_Rela *)
1248 ((const char *)ef->pltrela + ef->pltrelasize);
1249 while (rela < relalim) {
1250 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1251 ELF_RELOC_RELA, elf_lookup)) {
1252 symname = symbol_name(ef, rela->r_info);
1253 printf("link_elf: symbol %s undefined\n",
1254 symname);
1255 return (ENOENT);
1256 }
1257 rela++;
1258 }
1259 }
1260
1261 return (0);
1262 }
1263
1264 /*
1265 * Hash function for symbol table lookup. Don't even think about changing
1266 * this. It is specified by the System V ABI.
1267 */
1268 static unsigned long
1269 elf_hash(const char *name)
1270 {
1271 const unsigned char *p = (const unsigned char *) name;
1272 unsigned long h = 0;
1273 unsigned long g;
1274
1275 while (*p != '\0') {
1276 h = (h << 4) + *p++;
1277 if ((g = h & 0xf0000000) != 0)
1278 h ^= g >> 24;
1279 h &= ~g;
1280 }
1281 return (h);
1282 }
1283
1284 static int
1285 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1286 {
1287 elf_file_t ef = (elf_file_t) lf;
1288 unsigned long symnum;
1289 const Elf_Sym* symp;
1290 const char *strp;
1291 unsigned long hash;
1292 int i;
1293
1294 /* If we don't have a hash, bail. */
1295 if (ef->buckets == NULL || ef->nbuckets == 0) {
1296 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1297 return (ENOENT);
1298 }
1299
1300 /* First, search hashed global symbols */
1301 hash = elf_hash(name);
1302 symnum = ef->buckets[hash % ef->nbuckets];
1303
1304 while (symnum != STN_UNDEF) {
1305 if (symnum >= ef->nchains) {
1306 printf("%s: corrupt symbol table\n", __func__);
1307 return (ENOENT);
1308 }
1309
1310 symp = ef->symtab + symnum;
1311 if (symp->st_name == 0) {
1312 printf("%s: corrupt symbol table\n", __func__);
1313 return (ENOENT);
1314 }
1315
1316 strp = ef->strtab + symp->st_name;
1317
1318 if (strcmp(name, strp) == 0) {
1319 if (symp->st_shndx != SHN_UNDEF ||
1320 (symp->st_value != 0 &&
1321 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1322 *sym = (c_linker_sym_t) symp;
1323 return (0);
1324 }
1325 return (ENOENT);
1326 }
1327
1328 symnum = ef->chains[symnum];
1329 }
1330
1331 /* If we have not found it, look at the full table (if loaded) */
1332 if (ef->symtab == ef->ddbsymtab)
1333 return (ENOENT);
1334
1335 /* Exhaustive search */
1336 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1337 strp = ef->ddbstrtab + symp->st_name;
1338 if (strcmp(name, strp) == 0) {
1339 if (symp->st_shndx != SHN_UNDEF ||
1340 (symp->st_value != 0 &&
1341 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1342 *sym = (c_linker_sym_t) symp;
1343 return (0);
1344 }
1345 return (ENOENT);
1346 }
1347 }
1348
1349 return (ENOENT);
1350 }
1351
1352 static int
1353 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1354 linker_symval_t *symval)
1355 {
1356 elf_file_t ef = (elf_file_t) lf;
1357 const Elf_Sym* es = (const Elf_Sym*) sym;
1358
1359 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1360 symval->name = ef->strtab + es->st_name;
1361 symval->value = (caddr_t) ef->address + es->st_value;
1362 symval->size = es->st_size;
1363 return (0);
1364 }
1365 if (ef->symtab == ef->ddbsymtab)
1366 return (ENOENT);
1367 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1368 symval->name = ef->ddbstrtab + es->st_name;
1369 symval->value = (caddr_t) ef->address + es->st_value;
1370 symval->size = es->st_size;
1371 return (0);
1372 }
1373 return (ENOENT);
1374 }
1375
1376 static int
1377 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1378 c_linker_sym_t *sym, long *diffp)
1379 {
1380 elf_file_t ef = (elf_file_t) lf;
1381 u_long off = (uintptr_t) (void *) value;
1382 u_long diff = off;
1383 u_long st_value;
1384 const Elf_Sym* es;
1385 const Elf_Sym* best = NULL;
1386 int i;
1387
1388 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1389 if (es->st_name == 0)
1390 continue;
1391 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1392 if (off >= st_value) {
1393 if (off - st_value < diff) {
1394 diff = off - st_value;
1395 best = es;
1396 if (diff == 0)
1397 break;
1398 } else if (off - st_value == diff) {
1399 best = es;
1400 }
1401 }
1402 }
1403 if (best == NULL)
1404 *diffp = off;
1405 else
1406 *diffp = diff;
1407 *sym = (c_linker_sym_t) best;
1408
1409 return (0);
1410 }
1411
1412 /*
1413 * Look up a linker set on an ELF system.
1414 */
1415 static int
1416 link_elf_lookup_set(linker_file_t lf, const char *name,
1417 void ***startp, void ***stopp, int *countp)
1418 {
1419 c_linker_sym_t sym;
1420 linker_symval_t symval;
1421 char *setsym;
1422 void **start, **stop;
1423 int len, error = 0, count;
1424
1425 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1426 setsym = malloc(len, M_LINKER, M_WAITOK);
1427
1428 /* get address of first entry */
1429 snprintf(setsym, len, "%s%s", "__start_set_", name);
1430 error = link_elf_lookup_symbol(lf, setsym, &sym);
1431 if (error != 0)
1432 goto out;
1433 link_elf_symbol_values(lf, sym, &symval);
1434 if (symval.value == 0) {
1435 error = ESRCH;
1436 goto out;
1437 }
1438 start = (void **)symval.value;
1439
1440 /* get address of last entry */
1441 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1442 error = link_elf_lookup_symbol(lf, setsym, &sym);
1443 if (error != 0)
1444 goto out;
1445 link_elf_symbol_values(lf, sym, &symval);
1446 if (symval.value == 0) {
1447 error = ESRCH;
1448 goto out;
1449 }
1450 stop = (void **)symval.value;
1451
1452 /* and the number of entries */
1453 count = stop - start;
1454
1455 /* and copy out */
1456 if (startp != NULL)
1457 *startp = start;
1458 if (stopp != NULL)
1459 *stopp = stop;
1460 if (countp != NULL)
1461 *countp = count;
1462
1463 out:
1464 free(setsym, M_LINKER);
1465 return (error);
1466 }
1467
1468 static int
1469 link_elf_each_function_name(linker_file_t file,
1470 int (*callback)(const char *, void *), void *opaque)
1471 {
1472 elf_file_t ef = (elf_file_t)file;
1473 const Elf_Sym *symp;
1474 int i, error;
1475
1476 /* Exhaustive search */
1477 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1478 if (symp->st_value != 0 &&
1479 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1480 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1481 if (error != 0)
1482 return (error);
1483 }
1484 }
1485 return (0);
1486 }
1487
1488 static int
1489 link_elf_each_function_nameval(linker_file_t file,
1490 linker_function_nameval_callback_t callback, void *opaque)
1491 {
1492 linker_symval_t symval;
1493 elf_file_t ef = (elf_file_t)file;
1494 const Elf_Sym* symp;
1495 int i, error;
1496
1497 /* Exhaustive search */
1498 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1499 if (symp->st_value != 0 &&
1500 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1501 error = link_elf_symbol_values(file,
1502 (c_linker_sym_t) symp, &symval);
1503 if (error != 0)
1504 return (error);
1505 error = callback(file, i, &symval, opaque);
1506 if (error != 0)
1507 return (error);
1508 }
1509 }
1510 return (0);
1511 }
1512
1513 const Elf_Sym *
1514 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1515 {
1516 elf_file_t ef = (elf_file_t)lf;
1517
1518 if (symidx >= ef->nchains)
1519 return (NULL);
1520 return (ef->symtab + symidx);
1521 }
1522
1523 const char *
1524 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1525 {
1526 elf_file_t ef = (elf_file_t)lf;
1527 const Elf_Sym *sym;
1528
1529 if (symidx >= ef->nchains)
1530 return (NULL);
1531 sym = ef->symtab + symidx;
1532 return (ef->strtab + sym->st_name);
1533 }
1534
1535 /*
1536 * Symbol lookup function that can be used when the symbol index is known (ie
1537 * in relocations). It uses the symbol index instead of doing a fully fledged
1538 * hash table based lookup when such is valid. For example for local symbols.
1539 * This is not only more efficient, it's also more correct. It's not always
1540 * the case that the symbol can be found through the hash table.
1541 */
1542 static int
1543 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1544 {
1545 elf_file_t ef = (elf_file_t)lf;
1546 const Elf_Sym *sym;
1547 const char *symbol;
1548 Elf_Addr addr, start, base;
1549
1550 /* Don't even try to lookup the symbol if the index is bogus. */
1551 if (symidx >= ef->nchains) {
1552 *res = 0;
1553 return (EINVAL);
1554 }
1555
1556 sym = ef->symtab + symidx;
1557
1558 /*
1559 * Don't do a full lookup when the symbol is local. It may even
1560 * fail because it may not be found through the hash table.
1561 */
1562 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1563 /* Force lookup failure when we have an insanity. */
1564 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1565 *res = 0;
1566 return (EINVAL);
1567 }
1568 *res = ((Elf_Addr)ef->address + sym->st_value);
1569 return (0);
1570 }
1571
1572 /*
1573 * XXX we can avoid doing a hash table based lookup for global
1574 * symbols as well. This however is not always valid, so we'll
1575 * just do it the hard way for now. Performance tweaks can
1576 * always be added.
1577 */
1578
1579 symbol = ef->strtab + sym->st_name;
1580
1581 /* Force a lookup failure if the symbol name is bogus. */
1582 if (*symbol == 0) {
1583 *res = 0;
1584 return (EINVAL);
1585 }
1586
1587 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1588 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1589 *res = 0;
1590 return (EINVAL);
1591 }
1592
1593 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1594 addr = addr - start + base;
1595 #ifdef VIMAGE
1596 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1597 addr = addr - start + base;
1598 #endif
1599 *res = addr;
1600 return (0);
1601 }
1602
1603 static void
1604 link_elf_reloc_local(linker_file_t lf)
1605 {
1606 const Elf_Rel *rellim;
1607 const Elf_Rel *rel;
1608 const Elf_Rela *relalim;
1609 const Elf_Rela *rela;
1610 elf_file_t ef = (elf_file_t)lf;
1611
1612 /* Perform relocations without addend if there are any: */
1613 if ((rel = ef->rel) != NULL) {
1614 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1615 while (rel < rellim) {
1616 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1617 ELF_RELOC_REL, elf_lookup);
1618 rel++;
1619 }
1620 }
1621
1622 /* Perform relocations with addend if there are any: */
1623 if ((rela = ef->rela) != NULL) {
1624 relalim = (const Elf_Rela *)
1625 ((const char *)ef->rela + ef->relasize);
1626 while (rela < relalim) {
1627 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1628 ELF_RELOC_RELA, elf_lookup);
1629 rela++;
1630 }
1631 }
1632 }
1633
1634 static long
1635 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1636 {
1637 elf_file_t ef = (elf_file_t)lf;
1638
1639 *symtab = ef->ddbsymtab;
1640
1641 if (*symtab == NULL)
1642 return (0);
1643
1644 return (ef->ddbsymcnt);
1645 }
1646
1647 static long
1648 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1649 {
1650 elf_file_t ef = (elf_file_t)lf;
1651
1652 *strtab = ef->ddbstrtab;
1653
1654 if (*strtab == NULL)
1655 return (0);
1656
1657 return (ef->ddbstrcnt);
1658 }
Cache object: 025bd249014e92e38f20ba7acdfc1a20
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