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kernel - Force NFSv3 for diskless nfs mount
[dragonfly.git] / sys / kern / link_elf.c
blob9f7b05d4e460bc3b6925be0679f0e1a8031b1339
1 /*-
2 * Copyright (c) 1998 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 * $FreeBSD: src/sys/kern/link_elf.c,v 1.24 1999/12/24 15:33:36 bde Exp $
27 * $DragonFly: src/sys/kern/link_elf.c,v 1.29 2008/08/01 23:11:16 dillon Exp $
28 */
29
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/systm.h>
33 #include <sys/malloc.h>
34 #include <sys/proc.h>
35 #include <sys/nlookup.h>
36 #include <sys/fcntl.h>
37 #include <sys/vnode.h>
38 #include <sys/linker.h>
39 #include <machine/elf.h>
40
41 #include <vm/vm.h>
42 #include <vm/vm_param.h>
43 #include <vm/vm_zone.h>
44 #include <sys/lock.h>
45 #ifdef SPARSE_MAPPING
46 #include <vm/vm_object.h>
47 #include <vm/vm_kern.h>
48 #include <vm/vm_extern.h>
49 #endif
50 #include <vm/pmap.h>
51 #include <vm/vm_map.h>
52
53 #if defined(__amd64__) && defined(_KERNEL_VIRTUAL)
54 #include <stdio.h>
55 #endif
56
57 static int link_elf_preload_file(const char *, linker_file_t *);
58 static int link_elf_preload_finish(linker_file_t);
59 static int link_elf_load_file(const char*, linker_file_t*);
60 static int link_elf_lookup_symbol(linker_file_t, const char*,
61 c_linker_sym_t*);
62 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
63 static int link_elf_search_symbol(linker_file_t, caddr_t value,
64 c_linker_sym_t* sym, long* diffp);
65
66 static void link_elf_unload_file(linker_file_t);
67 static void link_elf_unload_module(linker_file_t);
68 static int link_elf_lookup_set(linker_file_t, const char *,
69 void ***, void ***, int *);
70 static int elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *);
71 static void link_elf_reloc_local(linker_file_t lf);
72
73 static struct linker_class_ops link_elf_class_ops = {
74 link_elf_load_file,
75 link_elf_preload_file,
76 };
77
78 static struct linker_file_ops link_elf_file_ops = {
79 .lookup_symbol = link_elf_lookup_symbol,
80 .symbol_values = link_elf_symbol_values,
81 .search_symbol = link_elf_search_symbol,
82 .unload = link_elf_unload_file,
83 .lookup_set = link_elf_lookup_set
84 };
85
86 static struct linker_file_ops link_elf_module_ops = {
87 .lookup_symbol = link_elf_lookup_symbol,
88 .symbol_values = link_elf_symbol_values,
89 .search_symbol = link_elf_search_symbol,
90 .preload_finish = link_elf_preload_finish,
91 .unload = link_elf_unload_module,
92 .lookup_set = link_elf_lookup_set,
93 };
94
95 typedef struct elf_file {
96 caddr_t address; /* Relocation address */
97 #ifdef SPARSE_MAPPING
98 vm_object_t object; /* VM object to hold file pages */
99 #endif
100 const Elf_Dyn* dynamic; /* Symbol table etc. */
101 Elf_Hashelt nbuckets; /* DT_HASH info */
102 Elf_Hashelt nchains;
103 const Elf_Hashelt* buckets;
104 const Elf_Hashelt* chains;
105 caddr_t hash;
106 caddr_t strtab; /* DT_STRTAB */
107 int strsz; /* DT_STRSZ */
108 const Elf_Sym* symtab; /* DT_SYMTAB */
109 Elf_Addr* got; /* DT_PLTGOT */
110 const Elf_Rel* pltrel; /* DT_JMPREL */
111 int pltrelsize; /* DT_PLTRELSZ */
112 const Elf_Rela* pltrela; /* DT_JMPREL */
113 int pltrelasize; /* DT_PLTRELSZ */
114 const Elf_Rel* rel; /* DT_REL */
115 int relsize; /* DT_RELSZ */
116 const Elf_Rela* rela; /* DT_RELA */
117 int relasize; /* DT_RELASZ */
118 caddr_t modptr;
119 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
120 long ddbsymcnt; /* Number of symbols */
121 caddr_t ddbstrtab; /* String table */
122 long ddbstrcnt; /* number of bytes in string table */
123 caddr_t symbase; /* malloc'ed symbold base */
124 caddr_t strbase; /* malloc'ed string base */
125 } *elf_file_t;
126
127 static int parse_dynamic(linker_file_t lf);
128 static int relocate_file(linker_file_t lf);
129 static int parse_module_symbols(linker_file_t lf);
130
131 /*
132 * The kernel symbol table starts here.
133 */
134 extern struct _dynamic _DYNAMIC;
135
136 static void
137 link_elf_init(void* arg)
138 {
139 Elf_Dyn *dp;
140 caddr_t modptr, baseptr, sizeptr;
141 elf_file_t ef;
142 char *modname;
143
144 #if ELF_TARG_CLASS == ELFCLASS32
145 linker_add_class("elf32", NULL, &link_elf_class_ops);
146 #else
147 linker_add_class("elf64", NULL, &link_elf_class_ops);
148 #endif
149
150 dp = (Elf_Dyn*) &_DYNAMIC;
151 if (dp) {
152 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_INTWAIT | M_ZERO);
153 ef->address = 0;
154 #ifdef SPARSE_MAPPING
155 ef->object = 0;
156 #endif
157 ef->dynamic = dp;
158 modname = NULL;
159 modptr = preload_search_by_type("elf kernel");
160 if (modptr)
161 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
162 if (modname == NULL)
163 modname = "kernel";
164 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops);
165 if (linker_kernel_file == NULL)
166 panic("link_elf_init: Can't create linker structures for kernel");
167 parse_dynamic(linker_kernel_file);
168 #if defined(__amd64__) && defined(_KERNEL_VIRTUAL)
169 fprintf(stderr, "WARNING: KERNBASE being used\n");
170 #endif
171 linker_kernel_file->address = (caddr_t) KERNBASE;
172 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
173
174 if (modptr) {
175 ef->modptr = modptr;
176 baseptr = preload_search_info(modptr, MODINFO_ADDR);
177 if (baseptr)
178 linker_kernel_file->address = *(caddr_t *)baseptr;
179 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
180 if (sizeptr)
181 linker_kernel_file->size = *(size_t *)sizeptr;
182 }
183 parse_module_symbols(linker_kernel_file);
184 linker_current_file = linker_kernel_file;
185 linker_kernel_file->flags |= LINKER_FILE_LINKED;
186 }
187 }
188
189 SYSINIT(link_elf, SI_BOOT2_KLD, SI_ORDER_SECOND, link_elf_init, 0);
190
191 static int
192 parse_module_symbols(linker_file_t lf)
193 {
194 elf_file_t ef = lf->priv;
195 caddr_t pointer;
196 caddr_t ssym, esym, base;
197 caddr_t strtab;
198 int strcnt;
199 Elf_Sym* symtab;
200 int symcnt;
201
202 if (ef->modptr == NULL)
203 return 0;
204 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
205 if (pointer == NULL)
206 return 0;
207 ssym = *(caddr_t *)pointer;
208 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
209 if (pointer == NULL)
210 return 0;
211 esym = *(caddr_t *)pointer;
212
213 base = ssym;
214
215 symcnt = *(long *)base;
216 base += sizeof(long);
217 symtab = (Elf_Sym *)base;
218 base += roundup(symcnt, sizeof(long));
219
220 if (base > esym || base < ssym) {
221 kprintf("Symbols are corrupt!\n");
222 return EINVAL;
223 }
224
225 strcnt = *(long *)base;
226 base += sizeof(long);
227 strtab = base;
228 base += roundup(strcnt, sizeof(long));
229
230 if (base > esym || base < ssym) {
231 kprintf("Symbols are corrupt!\n");
232 return EINVAL;
233 }
234
235 ef->ddbsymtab = symtab;
236 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
237 ef->ddbstrtab = strtab;
238 ef->ddbstrcnt = strcnt;
239
240 return 0;
241 }
242
243 static int
244 parse_dynamic(linker_file_t lf)
245 {
246 elf_file_t ef = lf->priv;
247 const Elf_Dyn *dp;
248 int plttype = DT_REL;
249
250 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
251 switch (dp->d_tag) {
252 case DT_HASH:
253 {
254 /* From src/libexec/rtld-elf/rtld.c */
255 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
256 (ef->address + dp->d_un.d_ptr);
257 ef->nbuckets = hashtab[0];
258 ef->nchains = hashtab[1];
259 ef->buckets = hashtab + 2;
260 ef->chains = ef->buckets + ef->nbuckets;
261 break;
262 }
263 case DT_STRTAB:
264 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
265 break;
266 case DT_STRSZ:
267 ef->strsz = dp->d_un.d_val;
268 break;
269 case DT_SYMTAB:
270 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
271 break;
272 case DT_SYMENT:
273 if (dp->d_un.d_val != sizeof(Elf_Sym))
274 return ENOEXEC;
275 break;
276 case DT_PLTGOT:
277 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
278 break;
279 case DT_REL:
280 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
281 break;
282 case DT_RELSZ:
283 ef->relsize = dp->d_un.d_val;
284 break;
285 case DT_RELENT:
286 if (dp->d_un.d_val != sizeof(Elf_Rel))
287 return ENOEXEC;
288 break;
289 case DT_JMPREL:
290 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
291 break;
292 case DT_PLTRELSZ:
293 ef->pltrelsize = dp->d_un.d_val;
294 break;
295 case DT_RELA:
296 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
297 break;
298 case DT_RELASZ:
299 ef->relasize = dp->d_un.d_val;
300 break;
301 case DT_RELAENT:
302 if (dp->d_un.d_val != sizeof(Elf_Rela))
303 return ENOEXEC;
304 break;
305 case DT_PLTREL:
306 plttype = dp->d_un.d_val;
307 if (plttype != DT_REL && plttype != DT_RELA)
308 return ENOEXEC;
309 break;
310 }
311 }
312
313 if (plttype == DT_RELA) {
314 ef->pltrela = (const Elf_Rela *) ef->pltrel;
315 ef->pltrel = NULL;
316 ef->pltrelasize = ef->pltrelsize;
317 ef->pltrelsize = 0;
318 }
319
320 ef->ddbsymtab = ef->symtab;
321 ef->ddbsymcnt = ef->nchains;
322 ef->ddbstrtab = ef->strtab;
323 ef->ddbstrcnt = ef->strsz;
324
325 return 0;
326 }
327
328 static void
329 link_elf_error(const char *s)
330 {
331 kprintf("kldload: %s\n", s);
332 }
333
334 static int
335 link_elf_preload_file(const char *filename, linker_file_t *result)
336 {
337 caddr_t modptr, baseptr, sizeptr, dynptr;
338 char *type;
339 elf_file_t ef;
340 linker_file_t lf;
341 int error;
342 vm_offset_t dp;
343
344 /*
345 * Look to see if we have the module preloaded.
346 */
347 modptr = preload_search_by_name(filename);
348 if (modptr == NULL)
349 return ENOENT;
350
351 /* It's preloaded, check we can handle it and collect information */
352 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
353 baseptr = preload_search_info(modptr, MODINFO_ADDR);
354 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
355 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
356 if (type == NULL ||
357 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
358 strcmp(type, "elf module") != 0))
359 return (EFTYPE);
360 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
361 return (EINVAL);
362
363 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
364 ef->modptr = modptr;
365 ef->address = *(caddr_t *)baseptr;
366 #ifdef SPARSE_MAPPING
367 ef->object = 0;
368 #endif
369 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
370 ef->dynamic = (Elf_Dyn *)dp;
371 lf = linker_make_file(filename, ef, &link_elf_module_ops);
372 if (lf == NULL) {
373 kfree(ef, M_LINKER);
374 return ENOMEM;
375 }
376 lf->address = ef->address;
377 lf->size = *(size_t *)sizeptr;
378
379 error = parse_dynamic(lf);
380 if (error) {
381 linker_file_unload(lf);
382 return error;
383 }
384 link_elf_reloc_local(lf);
385 *result = lf;
386 return (0);
387 }
388
389 static int
390 link_elf_preload_finish(linker_file_t lf)
391 {
392 int error;
393
394 error = relocate_file(lf);
395 if (error)
396 return error;
397 parse_module_symbols(lf);
398
399 return (0);
400 }
401
402 static int
403 link_elf_load_file(const char* filename, linker_file_t* result)
404 {
405 struct nlookupdata nd;
406 struct thread *td = curthread; /* XXX */
407 struct proc *p = td->td_proc;
408 struct vnode *vp;
409 Elf_Ehdr *hdr;
410 caddr_t firstpage;
411 int nbytes, i;
412 Elf_Phdr *phdr;
413 Elf_Phdr *phlimit;
414 Elf_Phdr *segs[2];
415 int nsegs;
416 Elf_Phdr *phdyn;
417 Elf_Phdr *phphdr;
418 caddr_t mapbase;
419 size_t mapsize;
420 Elf_Off base_offset;
421 Elf_Addr base_vaddr;
422 Elf_Addr base_vlimit;
423 int error = 0;
424 int resid;
425 elf_file_t ef;
426 linker_file_t lf;
427 char *pathname;
428 Elf_Shdr *shdr;
429 int symtabindex;
430 int symstrindex;
431 int symcnt;
432 int strcnt;
433
434 /* XXX Hack for firmware loading where p == NULL */
435 if (p == NULL) {
436 p = &proc0;
437 }
438
439 KKASSERT(p != NULL);
440 if (p->p_ucred == NULL) {
441 kprintf("link_elf_load_file: cannot load '%s' from filesystem"
442 " this early\n", filename);
443 return ENOENT;
444 }
445 shdr = NULL;
446 lf = NULL;
447 pathname = linker_search_path(filename);
448 if (pathname == NULL)
449 return ENOENT;
450
451 error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
452 if (error == 0)
453 error = vn_open(&nd, NULL, FREAD, 0);
454 kfree(pathname, M_LINKER);
455 if (error) {
456 nlookup_done(&nd);
457 return error;
458 }
459 vp = nd.nl_open_vp;
460 nd.nl_open_vp = NULL;
461 nlookup_done(&nd);
462
463 /*
464 * Read the elf header from the file.
465 */
466 firstpage = kmalloc(PAGE_SIZE, M_LINKER, M_WAITOK);
467 hdr = (Elf_Ehdr *)firstpage;
468 error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0,
469 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
470 nbytes = PAGE_SIZE - resid;
471 if (error)
472 goto out;
473
474 if (!IS_ELF(*hdr)) {
475 error = ENOEXEC;
476 goto out;
477 }
478
479 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
480 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
481 link_elf_error("Unsupported file layout");
482 error = ENOEXEC;
483 goto out;
484 }
485 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
486 || hdr->e_version != EV_CURRENT) {
487 link_elf_error("Unsupported file version");
488 error = ENOEXEC;
489 goto out;
490 }
491 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
492 error = ENOSYS;
493 goto out;
494 }
495 if (hdr->e_machine != ELF_TARG_MACH) {
496 link_elf_error("Unsupported machine");
497 error = ENOEXEC;
498 goto out;
499 }
500
501 /*
502 * We rely on the program header being in the first page. This is
503 * not strictly required by the ABI specification, but it seems to
504 * always true in practice. And, it simplifies things considerably.
505 */
506 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
507 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
508 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
509 link_elf_error("Unreadable program headers");
510
511 /*
512 * Scan the program header entries, and save key information.
513 *
514 * We rely on there being exactly two load segments, text and data,
515 * in that order.
516 */
517 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
518 phlimit = phdr + hdr->e_phnum;
519 nsegs = 0;
520 phdyn = NULL;
521 phphdr = NULL;
522 while (phdr < phlimit) {
523 switch (phdr->p_type) {
524
525 case PT_LOAD:
526 if (nsegs == 2) {
527 link_elf_error("Too many sections");
528 error = ENOEXEC;
529 goto out;
530 }
531 segs[nsegs] = phdr;
532 ++nsegs;
533 break;
534
535 case PT_PHDR:
536 phphdr = phdr;
537 break;
538
539 case PT_DYNAMIC:
540 phdyn = phdr;
541 break;
542
543 case PT_INTERP:
544 error = ENOSYS;
545 goto out;
546 }
547
548 ++phdr;
549 }
550 if (phdyn == NULL) {
551 link_elf_error("Object is not dynamically-linked");
552 error = ENOEXEC;
553 goto out;
554 }
555
556 /*
557 * Allocate the entire address space of the object, to stake out our
558 * contiguous region, and to establish the base address for relocation.
559 */
560 base_offset = trunc_page(segs[0]->p_offset);
561 base_vaddr = trunc_page(segs[0]->p_vaddr);
562 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
563 mapsize = base_vlimit - base_vaddr;
564
565 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
566 #ifdef SPARSE_MAPPING
567 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
568 if (ef->object == NULL) {
569 kfree(ef, M_LINKER);
570 error = ENOMEM;
571 goto out;
572 }
573 vm_object_reference(ef->object);
574 ef->address = (caddr_t)vm_map_min(&kernel_map);
575 error = vm_map_find(&kernel_map, ef->object, 0,
576 (vm_offset_t *)&ef->address,
577 mapsize, PAGE_SIZE,
578 1, VM_MAPTYPE_NORMAL,
579 VM_PROT_ALL, VM_PROT_ALL,
580 0);
581 if (error) {
582 vm_object_deallocate(ef->object);
583 kfree(ef, M_LINKER);
584 goto out;
585 }
586 #else
587 ef->address = kmalloc(mapsize, M_LINKER, M_WAITOK);
588 #endif
589 mapbase = ef->address;
590
591 /*
592 * Read the text and data sections and zero the bss.
593 */
594 for (i = 0; i < 2; i++) {
595 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
596 error = vn_rdwr(UIO_READ, vp,
597 segbase, segs[i]->p_filesz, segs[i]->p_offset,
598 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
599 if (error) {
600 #ifdef SPARSE_MAPPING
601 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
602 (vm_offset_t) ef->address
603 + (ef->object->size << PAGE_SHIFT));
604 vm_object_deallocate(ef->object);
605 #else
606 kfree(ef->address, M_LINKER);
607 #endif
608 kfree(ef, M_LINKER);
609 goto out;
610 }
611 bzero(segbase + segs[i]->p_filesz,
612 segs[i]->p_memsz - segs[i]->p_filesz);
613
614 #ifdef SPARSE_MAPPING
615 /*
616 * Wire down the pages
617 */
618 vm_map_wire(&kernel_map,
619 (vm_offset_t) segbase,
620 (vm_offset_t) segbase + segs[i]->p_memsz,
621 0);
622 #endif
623 }
624
625 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
626
627 lf = linker_make_file(filename, ef, &link_elf_file_ops);
628 if (lf == NULL) {
629 #ifdef SPARSE_MAPPING
630 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
631 (vm_offset_t) ef->address
632 + (ef->object->size << PAGE_SHIFT));
633 vm_object_deallocate(ef->object);
634 #else
635 kfree(ef->address, M_LINKER);
636 #endif
637 kfree(ef, M_LINKER);
638 error = ENOMEM;
639 goto out;
640 }
641 lf->address = ef->address;
642 lf->size = mapsize;
643
644 error = parse_dynamic(lf);
645 if (error)
646 goto out;
647 link_elf_reloc_local(lf);
648 error = linker_load_dependencies(lf);
649 if (error)
650 goto out;
651 error = relocate_file(lf);
652 if (error)
653 goto out;
654
655 /* Try and load the symbol table if it's present. (you can strip it!) */
656 nbytes = hdr->e_shnum * hdr->e_shentsize;
657 if (nbytes == 0 || hdr->e_shoff == 0)
658 goto nosyms;
659 shdr = kmalloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
660 error = vn_rdwr(UIO_READ, vp,
661 (caddr_t)shdr, nbytes, hdr->e_shoff,
662 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
663 if (error)
664 goto out;
665 symtabindex = -1;
666 symstrindex = -1;
667 for (i = 0; i < hdr->e_shnum; i++) {
668 if (shdr[i].sh_type == SHT_SYMTAB) {
669 symtabindex = i;
670 symstrindex = shdr[i].sh_link;
671 }
672 }
673 if (symtabindex < 0 || symstrindex < 0)
674 goto nosyms;
675
676 symcnt = shdr[symtabindex].sh_size;
677 ef->symbase = kmalloc(symcnt, M_LINKER, M_WAITOK);
678 strcnt = shdr[symstrindex].sh_size;
679 ef->strbase = kmalloc(strcnt, M_LINKER, M_WAITOK);
680 error = vn_rdwr(UIO_READ, vp,
681 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
682 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
683 if (error)
684 goto out;
685 error = vn_rdwr(UIO_READ, vp,
686 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
687 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
688 if (error)
689 goto out;
690
691 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
692 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
693 ef->ddbstrcnt = strcnt;
694 ef->ddbstrtab = ef->strbase;
695
696 nosyms:
697
698 *result = lf;
699
700 out:
701 if (error && lf)
702 linker_file_unload(lf);
703 if (shdr)
704 kfree(shdr, M_LINKER);
705 if (firstpage)
706 kfree(firstpage, M_LINKER);
707 vn_unlock(vp);
708 vn_close(vp, FREAD);
709
710 return error;
711 }
712
713 Elf_Addr
714 elf_relocaddr(linker_file_t lf, Elf_Addr x)
715 {
716 elf_file_t ef;
717
718 ef = lf->priv;
719 #if 0
720 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
721 return ((x - ef->pcpu_start) + ef->pcpu_base);
722 #ifdef VIMAGE
723 if (x >= ef->vnet_start && x < ef->vnet_stop)
724 return ((x - ef->vnet_start) + ef->vnet_base);
725 #endif
726 #endif
727 return (x);
728 }
729
730 static void
731 link_elf_unload_file(linker_file_t file)
732 {
733 elf_file_t ef = file->priv;
734
735 if (ef) {
736 #ifdef SPARSE_MAPPING
737 if (ef->object) {
738 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
739 (vm_offset_t) ef->address
740 + (ef->object->size << PAGE_SHIFT));
741 vm_object_deallocate(ef->object);
742 }
743 #else
744 if (ef->address)
745 kfree(ef->address, M_LINKER);
746 #endif
747 if (ef->symbase)
748 kfree(ef->symbase, M_LINKER);
749 if (ef->strbase)
750 kfree(ef->strbase, M_LINKER);
751 kfree(ef, M_LINKER);
752 }
753 }
754
755 static void
756 link_elf_unload_module(linker_file_t file)
757 {
758 elf_file_t ef = file->priv;
759
760 if (ef)
761 kfree(ef, M_LINKER);
762 if (file->filename)
763 preload_delete_name(file->filename);
764 }
765
766 static const char *
767 symbol_name(elf_file_t ef, Elf_Size r_info)
768 {
769 const Elf_Sym *ref;
770
771 if (ELF_R_SYM(r_info)) {
772 ref = ef->symtab + ELF_R_SYM(r_info);
773 return ef->strtab + ref->st_name;
774 } else
775 return NULL;
776 }
777
778 static int
779 relocate_file(linker_file_t lf)
780 {
781 elf_file_t ef = lf->priv;
782 const Elf_Rel *rellim;
783 const Elf_Rel *rel;
784 const Elf_Rela *relalim;
785 const Elf_Rela *rela;
786 const char *symname;
787
788 /* Perform relocations without addend if there are any: */
789 rel = ef->rel;
790 if (rel) {
791 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
792 while (rel < rellim) {
793 if (elf_reloc(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup)) {
794 symname = symbol_name(ef, rel->r_info);
795 kprintf("link_elf: symbol %s undefined\n", symname);
796 return ENOENT;
797 }
798 rel++;
799 }
800 }
801
802 /* Perform relocations with addend if there are any: */
803 rela = ef->rela;
804 if (rela) {
805 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
806 while (rela < relalim) {
807 if (elf_reloc(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup)) {
808 symname = symbol_name(ef, rela->r_info);
809 kprintf("link_elf: symbol %s undefined\n", symname);
810 return ENOENT;
811 }
812 rela++;
813 }
814 }
815
816 /* Perform PLT relocations without addend if there are any: */
817 rel = ef->pltrel;
818 if (rel) {
819 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
820 while (rel < rellim) {
821 if (elf_reloc(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup)) {
822 symname = symbol_name(ef, rel->r_info);
823 kprintf("link_elf: symbol %s undefined\n", symname);
824 return ENOENT;
825 }
826 rel++;
827 }
828 }
829
830 /* Perform relocations with addend if there are any: */
831 rela = ef->pltrela;
832 if (rela) {
833 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
834 while (rela < relalim) {
835 symname = symbol_name(ef, rela->r_info);
836 if (elf_reloc(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup)) {
837 kprintf("link_elf: symbol %s undefined\n", symname);
838 return ENOENT;
839 }
840 rela++;
841 }
842 }
843
844 return 0;
845 }
846
847 /*
848 * Hash function for symbol table lookup. Don't even think about changing
849 * this. It is specified by the System V ABI.
850 */
851 static unsigned long
852 elf_hash(const char *name)
853 {
854 const unsigned char *p = (const unsigned char *) name;
855 unsigned long h = 0;
856 unsigned long g;
857
858 while (*p != '\0') {
859 h = (h << 4) + *p++;
860 if ((g = h & 0xf0000000) != 0)
861 h ^= g >> 24;
862 h &= ~g;
863 }
864 return h;
865 }
866
867 int
868 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
869 {
870 elf_file_t ef = lf->priv;
871 unsigned long symnum;
872 const Elf_Sym* symp;
873 const char *strp;
874 unsigned long hash;
875 int i;
876
877 /* If we don't have a hash, bail. */
878 if (ef->buckets == NULL || ef->nbuckets == 0) {
879 kprintf("link_elf_lookup_symbol: missing symbol hash table\n");
880 return ENOENT;
881 }
882
883 /* First, search hashed global symbols */
884 hash = elf_hash(name);
885 symnum = ef->buckets[hash % ef->nbuckets];
886
887 while (symnum != STN_UNDEF) {
888 if (symnum >= ef->nchains) {
889 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
890 return ENOENT;
891 }
892
893 symp = ef->symtab + symnum;
894 if (symp->st_name == 0) {
895 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
896 return ENOENT;
897 }
898
899 strp = ef->strtab + symp->st_name;
900
901 if (strcmp(name, strp) == 0) {
902 if (symp->st_shndx != SHN_UNDEF ||
903 (symp->st_value != 0 &&
904 ELF_ST_TYPE(symp->st_info) == STT_FUNC)
905 ) {
906 *sym = (c_linker_sym_t) symp;
907 return 0;
908 } else {
909 return ENOENT;
910 }
911 }
912
913 symnum = ef->chains[symnum];
914 }
915
916 /* If we have not found it, look at the full table (if loaded) */
917 if (ef->symtab == ef->ddbsymtab)
918 return ENOENT;
919
920 /* Exhaustive search */
921 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
922 strp = ef->ddbstrtab + symp->st_name;
923 if (strcmp(name, strp) == 0) {
924 if (symp->st_shndx != SHN_UNDEF ||
925 (symp->st_value != 0 &&
926 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
927 *sym = (c_linker_sym_t) symp;
928 return 0;
929 } else {
930 return ENOENT;
931 }
932 }
933 }
934 return ENOENT;
935 }
936
937 static int
938 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t *symval)
939 {
940 elf_file_t ef = lf->priv;
941 const Elf_Sym *es = (const Elf_Sym *)sym;
942
943 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) {
944 symval->name = ef->strtab + es->st_name;
945 symval->value = (caddr_t) ef->address + es->st_value;
946 symval->size = es->st_size;
947 return 0;
948 }
949 if (ef->symtab == ef->ddbsymtab)
950 return ENOENT;
951 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) {
952 symval->name = ef->ddbstrtab + es->st_name;
953 symval->value = (caddr_t) ef->address + es->st_value;
954 symval->size = es->st_size;
955 return 0;
956 }
957 return ENOENT;
958 }
959
960 static int
961 link_elf_search_symbol(linker_file_t lf, caddr_t value,
962 c_linker_sym_t *sym, long *diffp)
963 {
964 elf_file_t ef = lf->priv;
965 u_long off = (uintptr_t)(void *)value;
966 u_long diff = off;
967 u_long st_value;
968 const Elf_Sym *es;
969 const Elf_Sym *best = 0;
970 int i;
971
972 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
973 if (es->st_name == 0)
974 continue;
975 st_value = es->st_value + (uintptr_t)(void *)ef->address;
976 if (off >= st_value) {
977 if (off - st_value < diff) {
978 diff = off - st_value;
979 best = es;
980 if (diff == 0)
981 break;
982 } else if (off - st_value == diff) {
983 best = es;
984 }
985 }
986 }
987 if (best == 0)
988 *diffp = off;
989 else
990 *diffp = diff;
991 *sym = (c_linker_sym_t) best;
992
993 return 0;
994 }
995
996 /*
997 * Look up a linker set on an ELF system.
998 */
999 static int
1000 link_elf_lookup_set(linker_file_t lf, const char *name,
1001 void ***startp, void ***stopp, int *countp)
1002 {
1003 c_linker_sym_t sym;
1004 linker_symval_t symval;
1005 char *setsym;
1006 void **start, **stop;
1007 int len, error = 0, count;
1008
1009 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1010 setsym = kmalloc(len, M_LINKER, M_WAITOK);
1011
1012 /* get address of first entry */
1013 ksnprintf(setsym, len, "%s%s", "__start_set_", name);
1014 error = link_elf_lookup_symbol(lf, setsym, &sym);
1015 if (error)
1016 goto out;
1017 link_elf_symbol_values(lf, sym, &symval);
1018 if (symval.value == 0) {
1019 error = ESRCH;
1020 goto out;
1021 }
1022 start = (void **)symval.value;
1023
1024 /* get address of last entry */
1025 ksnprintf(setsym, len, "%s%s", "__stop_set_", name);
1026 error = link_elf_lookup_symbol(lf, setsym, &sym);
1027 if (error)
1028 goto out;
1029 link_elf_symbol_values(lf, sym, &symval);
1030 if (symval.value == 0) {
1031 error = ESRCH;
1032 goto out;
1033 }
1034 stop = (void **)symval.value;
1035
1036 /* and the number of entries */
1037 count = stop - start;
1038
1039 /* and copy out */
1040 if (startp)
1041 *startp = start;
1042 if (stopp)
1043 *stopp = stop;
1044 if (countp)
1045 *countp = count;
1046
1047 out:
1048 kfree(setsym, M_LINKER);
1049 return error;
1050 }
1051
1052 /*
1053 * Symbol lookup function that can be used when the symbol index is known (ie
1054 * in relocations). It uses the symbol index instead of doing a fully fledged
1055 * hash table based lookup when such is valid. For example for local symbols.
1056 * This is not only more efficient, it's also more correct. It's not always
1057 * the case that the symbol can be found through the hash table.
1058 */
1059 static int
1060 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *result)
1061 {
1062 elf_file_t ef = lf->priv;
1063 const Elf_Sym *sym;
1064 const char *symbol;
1065
1066 /* Don't even try to lookup the symbol if the index is bogus. */
1067 if (symidx >= ef->nchains)
1068 return (ENOENT);
1069
1070 sym = ef->symtab + symidx;
1071
1072 /*
1073 * Don't do a full lookup when the symbol is local. It may even
1074 * fail because it may not be found through the hash table.
1075 */
1076 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1077 /* Force lookup failure when we have an insanity. */
1078 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1079 return (ENOENT);
1080 return ((Elf_Addr) ef->address + sym->st_value);
1081 }
1082 /*
1083 * XXX we can avoid doing a hash table based lookup for global
1084 * symbols as well. This however is not always valid, so we'll
1085 * just do it the hard way for now. Performance tweaks can
1086 * always be added.
1087 */
1088
1089 symbol = ef->strtab + sym->st_name;
1090
1091 /* Force a lookup failure if the symbol name is bogus. */
1092 if (*symbol == 0)
1093 return (ENOENT);
1094
1095 return (linker_file_lookup_symbol(lf, symbol, deps, (caddr_t *)result));
1096 }
1097 static void
1098 link_elf_reloc_local(linker_file_t lf)
1099 {
1100 elf_file_t ef = lf->priv;
1101 const Elf_Rel *rellim;
1102 const Elf_Rel *rel;
1103 const Elf_Rela *relalim;
1104 const Elf_Rela *rela;
1105
1106 /* Perform relocations without addend if there are any: */
1107 if ((rel = ef->rel) != NULL) {
1108 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1109 while (rel < rellim) {
1110 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1111 elf_lookup);
1112 rel++;
1113 }
1114 }
1115
1116 /* Perform relocations with addend if there are any: */
1117 if ((rela = ef->rela) != NULL) {
1118 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1119 while (rela < relalim) {
1120 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1121 elf_lookup);
1122 rela++;
1123 }
1124 }
1125 }
DragonFly BSD