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Fix the fix.
[dragonfly.git] / sys / kern / link_elf.c
blob51e3e666a999ae043ce86d84acb577d4dd72d917
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 1.26 2007/04/30 07:18:54 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 static int link_elf_load_module(const char*, linker_file_t*);
54 static int link_elf_load_file(const char*, linker_file_t*);
55 static int link_elf_lookup_symbol(linker_file_t, const char*,
56 c_linker_sym_t*);
57 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
58 static int link_elf_search_symbol(linker_file_t, caddr_t value,
59 c_linker_sym_t* sym, long* diffp);
60
61 static void link_elf_unload_file(linker_file_t);
62 static void link_elf_unload_module(linker_file_t);
63 static int link_elf_lookup_set(linker_file_t, const char *,
64 void ***, void ***, int *);
65
66 static struct linker_class_ops link_elf_class_ops = {
67 link_elf_load_module,
68 };
69
70 static struct linker_file_ops link_elf_file_ops = {
71 link_elf_lookup_symbol,
72 link_elf_symbol_values,
73 link_elf_search_symbol,
74 link_elf_unload_file,
75 link_elf_lookup_set
76 };
77
78 static struct linker_file_ops link_elf_module_ops = {
79 link_elf_lookup_symbol,
80 link_elf_symbol_values,
81 link_elf_search_symbol,
82 link_elf_unload_module,
83 link_elf_lookup_set
84 };
85
86 typedef struct elf_file {
87 caddr_t address; /* Relocation address */
88 #ifdef SPARSE_MAPPING
89 vm_object_t object; /* VM object to hold file pages */
90 #endif
91 const Elf_Dyn* dynamic; /* Symbol table etc. */
92 Elf_Off nbuckets; /* DT_HASH info */
93 Elf_Off nchains;
94 const Elf_Off* buckets;
95 const Elf_Off* chains;
96 caddr_t hash;
97 caddr_t strtab; /* DT_STRTAB */
98 int strsz; /* DT_STRSZ */
99 const Elf_Sym* symtab; /* DT_SYMTAB */
100 Elf_Addr* got; /* DT_PLTGOT */
101 const Elf_Rel* pltrel; /* DT_JMPREL */
102 int pltrelsize; /* DT_PLTRELSZ */
103 const Elf_Rela* pltrela; /* DT_JMPREL */
104 int pltrelasize; /* DT_PLTRELSZ */
105 const Elf_Rel* rel; /* DT_REL */
106 int relsize; /* DT_RELSZ */
107 const Elf_Rela* rela; /* DT_RELA */
108 int relasize; /* DT_RELASZ */
109 caddr_t modptr;
110 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
111 long ddbsymcnt; /* Number of symbols */
112 caddr_t ddbstrtab; /* String table */
113 long ddbstrcnt; /* number of bytes in string table */
114 caddr_t symbase; /* malloc'ed symbold base */
115 caddr_t strbase; /* malloc'ed string base */
116 } *elf_file_t;
117
118 static int parse_dynamic(linker_file_t lf);
119 static int load_dependancies(linker_file_t lf);
120 static int relocate_file(linker_file_t lf);
121 static int parse_module_symbols(linker_file_t lf);
122
123 /*
124 * The kernel symbol table starts here.
125 */
126 extern struct _dynamic _DYNAMIC;
127
128 static void
129 link_elf_init(void* arg)
130 {
131 Elf_Dyn *dp;
132 caddr_t modptr, baseptr, sizeptr;
133 elf_file_t ef;
134 char *modname;
135
136 #if ELF_TARG_CLASS == ELFCLASS32
137 linker_add_class("elf32", NULL, &link_elf_class_ops);
138 #else
139 linker_add_class("elf64", NULL, &link_elf_class_ops);
140 #endif
141
142 dp = (Elf_Dyn*) &_DYNAMIC;
143 if (dp) {
144 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_INTWAIT | M_ZERO);
145 ef->address = 0;
146 #ifdef SPARSE_MAPPING
147 ef->object = 0;
148 #endif
149 ef->dynamic = dp;
150 modname = NULL;
151 modptr = preload_search_by_type("elf kernel");
152 if (modptr)
153 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
154 if (modname == NULL)
155 modname = "kernel";
156 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops);
157 if (linker_kernel_file == NULL)
158 panic("link_elf_init: Can't create linker structures for kernel");
159 parse_dynamic(linker_kernel_file);
160 linker_kernel_file->address = (caddr_t) KERNBASE;
161 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
162
163 if (modptr) {
164 ef->modptr = modptr;
165 baseptr = preload_search_info(modptr, MODINFO_ADDR);
166 if (baseptr)
167 linker_kernel_file->address = *(caddr_t *)baseptr;
168 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
169 if (sizeptr)
170 linker_kernel_file->size = *(size_t *)sizeptr;
171 }
172 parse_module_symbols(linker_kernel_file);
173 linker_current_file = linker_kernel_file;
174 linker_kernel_file->flags |= LINKER_FILE_LINKED;
175 }
176 }
177
178 SYSINIT(link_elf, SI_BOOT2_KLD, SI_ORDER_SECOND, link_elf_init, 0);
179
180 static int
181 parse_module_symbols(linker_file_t lf)
182 {
183 elf_file_t ef = lf->priv;
184 caddr_t pointer;
185 caddr_t ssym, esym, base;
186 caddr_t strtab;
187 int strcnt;
188 Elf_Sym* symtab;
189 int symcnt;
190
191 if (ef->modptr == NULL)
192 return 0;
193 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
194 if (pointer == NULL)
195 return 0;
196 ssym = *(caddr_t *)pointer;
197 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
198 if (pointer == NULL)
199 return 0;
200 esym = *(caddr_t *)pointer;
201
202 base = ssym;
203
204 symcnt = *(long *)base;
205 base += sizeof(long);
206 symtab = (Elf_Sym *)base;
207 base += roundup(symcnt, sizeof(long));
208
209 if (base > esym || base < ssym) {
210 kprintf("Symbols are corrupt!\n");
211 return EINVAL;
212 }
213
214 strcnt = *(long *)base;
215 base += sizeof(long);
216 strtab = base;
217 base += roundup(strcnt, sizeof(long));
218
219 if (base > esym || base < ssym) {
220 kprintf("Symbols are corrupt!\n");
221 return EINVAL;
222 }
223
224 ef->ddbsymtab = symtab;
225 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
226 ef->ddbstrtab = strtab;
227 ef->ddbstrcnt = strcnt;
228
229 return 0;
230 }
231
232 static int
233 parse_dynamic(linker_file_t lf)
234 {
235 elf_file_t ef = lf->priv;
236 const Elf_Dyn *dp;
237 int plttype = DT_REL;
238
239 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
240 switch (dp->d_tag) {
241 case DT_HASH:
242 {
243 /* From src/libexec/rtld-elf/rtld.c */
244 const Elf_Off *hashtab = (const Elf_Off *)
245 (ef->address + dp->d_un.d_ptr);
246 ef->nbuckets = hashtab[0];
247 ef->nchains = hashtab[1];
248 ef->buckets = hashtab + 2;
249 ef->chains = ef->buckets + ef->nbuckets;
250 break;
251 }
252 case DT_STRTAB:
253 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
254 break;
255 case DT_STRSZ:
256 ef->strsz = dp->d_un.d_val;
257 break;
258 case DT_SYMTAB:
259 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
260 break;
261 case DT_SYMENT:
262 if (dp->d_un.d_val != sizeof(Elf_Sym))
263 return ENOEXEC;
264 break;
265 case DT_PLTGOT:
266 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
267 break;
268 case DT_REL:
269 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
270 break;
271 case DT_RELSZ:
272 ef->relsize = dp->d_un.d_val;
273 break;
274 case DT_RELENT:
275 if (dp->d_un.d_val != sizeof(Elf_Rel))
276 return ENOEXEC;
277 break;
278 case DT_JMPREL:
279 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
280 break;
281 case DT_PLTRELSZ:
282 ef->pltrelsize = dp->d_un.d_val;
283 break;
284 case DT_RELA:
285 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
286 break;
287 case DT_RELASZ:
288 ef->relasize = dp->d_un.d_val;
289 break;
290 case DT_RELAENT:
291 if (dp->d_un.d_val != sizeof(Elf_Rela))
292 return ENOEXEC;
293 break;
294 case DT_PLTREL:
295 plttype = dp->d_un.d_val;
296 if (plttype != DT_REL && plttype != DT_RELA)
297 return ENOEXEC;
298 break;
299 }
300 }
301
302 if (plttype == DT_RELA) {
303 ef->pltrela = (const Elf_Rela *) ef->pltrel;
304 ef->pltrel = NULL;
305 ef->pltrelasize = ef->pltrelsize;
306 ef->pltrelsize = 0;
307 }
308
309 ef->ddbsymtab = ef->symtab;
310 ef->ddbsymcnt = ef->nchains;
311 ef->ddbstrtab = ef->strtab;
312 ef->ddbstrcnt = ef->strsz;
313
314 return 0;
315 }
316
317 static void
318 link_elf_error(const char *s)
319 {
320 kprintf("kldload: %s\n", s);
321 }
322
323 static int
324 link_elf_load_module(const char *filename, linker_file_t *result)
325 {
326 caddr_t modptr, baseptr, sizeptr, dynptr;
327 char *type;
328 elf_file_t ef;
329 linker_file_t lf;
330 int error;
331 vm_offset_t dp;
332
333 /*
334 * Look to see if we have the module preloaded.
335 */
336 modptr = preload_search_by_name(filename);
337 if (modptr == NULL)
338 return (link_elf_load_file(filename, result));
339
340 /* It's preloaded, check we can handle it and collect information */
341 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
342 baseptr = preload_search_info(modptr, MODINFO_ADDR);
343 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
344 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
345 if (type == NULL || strcmp(type, "elf module") != 0)
346 return (EFTYPE);
347 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
348 return (EINVAL);
349
350 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
351 if (ef == NULL)
352 return (ENOMEM);
353 ef->modptr = modptr;
354 ef->address = *(caddr_t *)baseptr;
355 #ifdef SPARSE_MAPPING
356 ef->object = 0;
357 #endif
358 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
359 ef->dynamic = (Elf_Dyn *)dp;
360 lf = linker_make_file(filename, ef, &link_elf_module_ops);
361 if (lf == NULL) {
362 kfree(ef, M_LINKER);
363 return ENOMEM;
364 }
365 lf->address = ef->address;
366 lf->size = *(size_t *)sizeptr;
367
368 error = parse_dynamic(lf);
369 if (error) {
370 linker_file_unload(lf);
371 return error;
372 }
373 error = load_dependancies(lf);
374 if (error) {
375 linker_file_unload(lf);
376 return error;
377 }
378 error = relocate_file(lf);
379 if (error) {
380 linker_file_unload(lf);
381 return error;
382 }
383 parse_module_symbols(lf);
384 lf->flags |= LINKER_FILE_LINKED;
385 *result = lf;
386 return (0);
387 }
388
389 static int
390 link_elf_load_file(const char* filename, linker_file_t* result)
391 {
392 struct nlookupdata nd;
393 struct thread *td = curthread; /* XXX */
394 struct proc *p = td->td_proc;
395 struct vnode *vp;
396 Elf_Ehdr *hdr;
397 caddr_t firstpage;
398 int nbytes, i;
399 Elf_Phdr *phdr;
400 Elf_Phdr *phlimit;
401 Elf_Phdr *segs[2];
402 int nsegs;
403 Elf_Phdr *phdyn;
404 Elf_Phdr *phphdr;
405 caddr_t mapbase;
406 size_t mapsize;
407 Elf_Off base_offset;
408 Elf_Addr base_vaddr;
409 Elf_Addr base_vlimit;
410 int error = 0;
411 int resid;
412 elf_file_t ef;
413 linker_file_t lf;
414 char *pathname;
415 Elf_Shdr *shdr;
416 int symtabindex;
417 int symstrindex;
418 int symcnt;
419 int strcnt;
420
421 KKASSERT(p != NULL);
422 if (p->p_ucred == NULL) {
423 kprintf("link_elf_load_file: cannot load '%s' from filesystem"
424 " this early\n", filename);
425 return ENOENT;
426 }
427 shdr = NULL;
428 lf = NULL;
429 pathname = linker_search_path(filename);
430 if (pathname == NULL)
431 return ENOENT;
432
433 error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
434 if (error == 0)
435 error = vn_open(&nd, NULL, FREAD, 0);
436 kfree(pathname, M_LINKER);
437 if (error) {
438 nlookup_done(&nd);
439 return error;
440 }
441 vp = nd.nl_open_vp;
442 nd.nl_open_vp = NULL;
443 nlookup_done(&nd);
444
445 /*
446 * Read the elf header from the file.
447 */
448 firstpage = kmalloc(PAGE_SIZE, M_LINKER, M_WAITOK);
449 if (firstpage == NULL) {
450 error = ENOMEM;
451 goto out;
452 }
453 hdr = (Elf_Ehdr *)firstpage;
454 error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0,
455 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
456 nbytes = PAGE_SIZE - resid;
457 if (error)
458 goto out;
459
460 if (!IS_ELF(*hdr)) {
461 error = ENOEXEC;
462 goto out;
463 }
464
465 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
466 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
467 link_elf_error("Unsupported file layout");
468 error = ENOEXEC;
469 goto out;
470 }
471 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
472 || hdr->e_version != EV_CURRENT) {
473 link_elf_error("Unsupported file version");
474 error = ENOEXEC;
475 goto out;
476 }
477 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
478 link_elf_error("Unsupported file type");
479 error = ENOEXEC;
480 goto out;
481 }
482 if (hdr->e_machine != ELF_TARG_MACH) {
483 link_elf_error("Unsupported machine");
484 error = ENOEXEC;
485 goto out;
486 }
487
488 /*
489 * We rely on the program header being in the first page. This is
490 * not strictly required by the ABI specification, but it seems to
491 * always true in practice. And, it simplifies things considerably.
492 */
493 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
494 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
495 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
496 link_elf_error("Unreadable program headers");
497
498 /*
499 * Scan the program header entries, and save key information.
500 *
501 * We rely on there being exactly two load segments, text and data,
502 * in that order.
503 */
504 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
505 phlimit = phdr + hdr->e_phnum;
506 nsegs = 0;
507 phdyn = NULL;
508 phphdr = NULL;
509 while (phdr < phlimit) {
510 switch (phdr->p_type) {
511
512 case PT_LOAD:
513 if (nsegs == 2) {
514 link_elf_error("Too many sections");
515 error = ENOEXEC;
516 goto out;
517 }
518 segs[nsegs] = phdr;
519 ++nsegs;
520 break;
521
522 case PT_PHDR:
523 phphdr = phdr;
524 break;
525
526 case PT_DYNAMIC:
527 phdyn = phdr;
528 break;
529 }
530
531 ++phdr;
532 }
533 if (phdyn == NULL) {
534 link_elf_error("Object is not dynamically-linked");
535 error = ENOEXEC;
536 goto out;
537 }
538
539 /*
540 * Allocate the entire address space of the object, to stake out our
541 * contiguous region, and to establish the base address for relocation.
542 */
543 base_offset = trunc_page(segs[0]->p_offset);
544 base_vaddr = trunc_page(segs[0]->p_vaddr);
545 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz);
546 mapsize = base_vlimit - base_vaddr;
547
548 ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO);
549 #ifdef SPARSE_MAPPING
550 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
551 if (ef->object == NULL) {
552 kfree(ef, M_LINKER);
553 error = ENOMEM;
554 goto out;
555 }
556 vm_object_reference(ef->object);
557 ef->address = (caddr_t)vm_map_min(&kernel_map);
558 error = vm_map_find(&kernel_map, ef->object, 0,
559 (vm_offset_t *)&ef->address, mapsize,
560 1,
561 VM_MAPTYPE_NORMAL,
562 VM_PROT_ALL, VM_PROT_ALL,
563 0);
564 if (error) {
565 vm_object_deallocate(ef->object);
566 kfree(ef, M_LINKER);
567 goto out;
568 }
569 #else
570 ef->address = kmalloc(mapsize, M_LINKER, M_WAITOK);
571 #endif
572 mapbase = ef->address;
573
574 /*
575 * Read the text and data sections and zero the bss.
576 */
577 for (i = 0; i < 2; i++) {
578 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
579 error = vn_rdwr(UIO_READ, vp,
580 segbase, segs[i]->p_filesz, segs[i]->p_offset,
581 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
582 if (error) {
583 #ifdef SPARSE_MAPPING
584 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
585 (vm_offset_t) ef->address
586 + (ef->object->size << PAGE_SHIFT));
587 vm_object_deallocate(ef->object);
588 #else
589 kfree(ef->address, M_LINKER);
590 #endif
591 kfree(ef, M_LINKER);
592 goto out;
593 }
594 bzero(segbase + segs[i]->p_filesz,
595 segs[i]->p_memsz - segs[i]->p_filesz);
596
597 #ifdef SPARSE_MAPPING
598 /*
599 * Wire down the pages
600 */
601 vm_map_wire(&kernel_map,
602 (vm_offset_t) segbase,
603 (vm_offset_t) segbase + segs[i]->p_memsz,
604 0);
605 #endif
606 }
607
608 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
609
610 lf = linker_make_file(filename, ef, &link_elf_file_ops);
611 if (lf == NULL) {
612 #ifdef SPARSE_MAPPING
613 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
614 (vm_offset_t) ef->address
615 + (ef->object->size << PAGE_SHIFT));
616 vm_object_deallocate(ef->object);
617 #else
618 kfree(ef->address, M_LINKER);
619 #endif
620 kfree(ef, M_LINKER);
621 error = ENOMEM;
622 goto out;
623 }
624 lf->address = ef->address;
625 lf->size = mapsize;
626
627 error = parse_dynamic(lf);
628 if (error)
629 goto out;
630 error = load_dependancies(lf);
631 if (error)
632 goto out;
633 error = relocate_file(lf);
634 if (error)
635 goto out;
636
637 /* Try and load the symbol table if it's present. (you can strip it!) */
638 nbytes = hdr->e_shnum * hdr->e_shentsize;
639 if (nbytes == 0 || hdr->e_shoff == 0)
640 goto nosyms;
641 shdr = kmalloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
642 if (shdr == NULL) {
643 error = ENOMEM;
644 goto out;
645 }
646 error = vn_rdwr(UIO_READ, vp,
647 (caddr_t)shdr, nbytes, hdr->e_shoff,
648 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
649 if (error)
650 goto out;
651 symtabindex = -1;
652 symstrindex = -1;
653 for (i = 0; i < hdr->e_shnum; i++) {
654 if (shdr[i].sh_type == SHT_SYMTAB) {
655 symtabindex = i;
656 symstrindex = shdr[i].sh_link;
657 }
658 }
659 if (symtabindex < 0 || symstrindex < 0)
660 goto nosyms;
661
662 symcnt = shdr[symtabindex].sh_size;
663 ef->symbase = kmalloc(symcnt, M_LINKER, M_WAITOK);
664 strcnt = shdr[symstrindex].sh_size;
665 ef->strbase = kmalloc(strcnt, M_LINKER, M_WAITOK);
666
667 if (ef->symbase == NULL || ef->strbase == NULL) {
668 error = ENOMEM;
669 goto out;
670 }
671 error = vn_rdwr(UIO_READ, vp,
672 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
673 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
674 if (error)
675 goto out;
676 error = vn_rdwr(UIO_READ, vp,
677 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
678 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
679 if (error)
680 goto out;
681
682 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
683 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
684 ef->ddbstrcnt = strcnt;
685 ef->ddbstrtab = ef->strbase;
686
687 lf->flags |= LINKER_FILE_LINKED;
688
689 nosyms:
690
691 *result = lf;
692
693 out:
694 if (error && lf)
695 linker_file_unload(lf);
696 if (shdr)
697 kfree(shdr, M_LINKER);
698 if (firstpage)
699 kfree(firstpage, M_LINKER);
700 vn_unlock(vp);
701 vn_close(vp, FREAD);
702
703 return error;
704 }
705
706 static void
707 link_elf_unload_file(linker_file_t file)
708 {
709 elf_file_t ef = file->priv;
710
711 if (ef) {
712 #ifdef SPARSE_MAPPING
713 if (ef->object) {
714 vm_map_remove(&kernel_map, (vm_offset_t) ef->address,
715 (vm_offset_t) ef->address
716 + (ef->object->size << PAGE_SHIFT));
717 vm_object_deallocate(ef->object);
718 }
719 #else
720 if (ef->address)
721 kfree(ef->address, M_LINKER);
722 #endif
723 if (ef->symbase)
724 kfree(ef->symbase, M_LINKER);
725 if (ef->strbase)
726 kfree(ef->strbase, M_LINKER);
727 kfree(ef, M_LINKER);
728 }
729 }
730
731 static void
732 link_elf_unload_module(linker_file_t file)
733 {
734 elf_file_t ef = file->priv;
735
736 if (ef)
737 kfree(ef, M_LINKER);
738 if (file->filename)
739 preload_delete_name(file->filename);
740 }
741
742 static int
743 load_dependancies(linker_file_t lf)
744 {
745 elf_file_t ef = lf->priv;
746 linker_file_t lfdep;
747 char* name;
748 const Elf_Dyn *dp;
749 int error = 0;
750
751 /*
752 * All files are dependant on /kernel.
753 */
754 if (linker_kernel_file) {
755 linker_kernel_file->refs++;
756 linker_file_add_dependancy(lf, linker_kernel_file);
757 }
758
759 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
760 if (dp->d_tag == DT_NEEDED) {
761 name = ef->strtab + dp->d_un.d_val;
762
763 error = linker_load_file(name, &lfdep);
764 if (error)
765 goto out;
766 error = linker_file_add_dependancy(lf, lfdep);
767 if (error)
768 goto out;
769 }
770 }
771
772 out:
773 return error;
774 }
775
776 static const char *
777 symbol_name(elf_file_t ef, Elf_Word r_info)
778 {
779 const Elf_Sym *ref;
780
781 if (ELF_R_SYM(r_info)) {
782 ref = ef->symtab + ELF_R_SYM(r_info);
783 return ef->strtab + ref->st_name;
784 } else
785 return NULL;
786 }
787
788 static int
789 relocate_file(linker_file_t lf)
790 {
791 elf_file_t ef = lf->priv;
792 const Elf_Rel *rellim;
793 const Elf_Rel *rel;
794 const Elf_Rela *relalim;
795 const Elf_Rela *rela;
796 const char *symname;
797
798 /* Perform relocations without addend if there are any: */
799 rel = ef->rel;
800 if (rel) {
801 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
802 while (rel < rellim) {
803 symname = symbol_name(ef, rel->r_info);
804 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) {
805 kprintf("link_elf: symbol %s undefined\n", symname);
806 return ENOENT;
807 }
808 rel++;
809 }
810 }
811
812 /* Perform relocations with addend if there are any: */
813 rela = ef->rela;
814 if (rela) {
815 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
816 while (rela < relalim) {
817 symname = symbol_name(ef, rela->r_info);
818 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) {
819 kprintf("link_elf: symbol %s undefined\n", symname);
820 return ENOENT;
821 }
822 rela++;
823 }
824 }
825
826 /* Perform PLT relocations without addend if there are any: */
827 rel = ef->pltrel;
828 if (rel) {
829 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
830 while (rel < rellim) {
831 symname = symbol_name(ef, rel->r_info);
832 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) {
833 kprintf("link_elf: symbol %s undefined\n", symname);
834 return ENOENT;
835 }
836 rel++;
837 }
838 }
839
840 /* Perform relocations with addend if there are any: */
841 rela = ef->pltrela;
842 if (rela) {
843 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
844 while (rela < relalim) {
845 symname = symbol_name(ef, rela->r_info);
846 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) {
847 kprintf("link_elf: symbol %s undefined\n", symname);
848 return ENOENT;
849 }
850 rela++;
851 }
852 }
853
854 return 0;
855 }
856
857 /*
858 * Hash function for symbol table lookup. Don't even think about changing
859 * this. It is specified by the System V ABI.
860 */
861 static unsigned long
862 elf_hash(const char *name)
863 {
864 const unsigned char *p = (const unsigned char *) name;
865 unsigned long h = 0;
866 unsigned long g;
867
868 while (*p != '\0') {
869 h = (h << 4) + *p++;
870 if ((g = h & 0xf0000000) != 0)
871 h ^= g >> 24;
872 h &= ~g;
873 }
874 return h;
875 }
876
877 int
878 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
879 {
880 elf_file_t ef = lf->priv;
881 unsigned long symnum;
882 const Elf_Sym* symp;
883 const char *strp;
884 unsigned long hash;
885 int i;
886
887 /* First, search hashed global symbols */
888 hash = elf_hash(name);
889 symnum = ef->buckets[hash % ef->nbuckets];
890
891 while (symnum != STN_UNDEF) {
892 if (symnum >= ef->nchains) {
893 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
894 return ENOENT;
895 }
896
897 symp = ef->symtab + symnum;
898 if (symp->st_name == 0) {
899 kprintf("link_elf_lookup_symbol: corrupt symbol table\n");
900 return ENOENT;
901 }
902
903 strp = ef->strtab + symp->st_name;
904
905 if (strcmp(name, strp) == 0) {
906 if (symp->st_shndx != SHN_UNDEF ||
907 (symp->st_value != 0 &&
908 ELF_ST_TYPE(symp->st_info) == STT_FUNC)
909 ) {
910 *sym = (c_linker_sym_t) symp;
911 return 0;
912 } else {
913 return ENOENT;
914 }
915 }
916
917 symnum = ef->chains[symnum];
918 }
919
920 /* If we have not found it, look at the full table (if loaded) */
921 if (ef->symtab == ef->ddbsymtab)
922 return ENOENT;
923
924 /* Exhaustive search */
925 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
926 strp = ef->ddbstrtab + symp->st_name;
927 if (strcmp(name, strp) == 0) {
928 if (symp->st_shndx != SHN_UNDEF ||
929 (symp->st_value != 0 &&
930 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
931 *sym = (c_linker_sym_t) symp;
932 return 0;
933 } else {
934 return ENOENT;
935 }
936 }
937 }
938 return ENOENT;
939 }
940
941 static int
942 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
943 {
944 elf_file_t ef = lf->priv;
945 const Elf_Sym* es = (const Elf_Sym*) sym;
946
947 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) {
948 symval->name = ef->strtab + es->st_name;
949 symval->value = (caddr_t) ef->address + es->st_value;
950 symval->size = es->st_size;
951 return 0;
952 }
953 if (ef->symtab == ef->ddbsymtab)
954 return ENOENT;
955 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) {
956 symval->name = ef->ddbstrtab + es->st_name;
957 symval->value = (caddr_t) ef->address + es->st_value;
958 symval->size = es->st_size;
959 return 0;
960 }
961 return ENOENT;
962 }
963
964 static int
965 link_elf_search_symbol(linker_file_t lf, caddr_t value,
966 c_linker_sym_t* sym, long* diffp)
967 {
968 elf_file_t ef = lf->priv;
969 u_long off = (uintptr_t) (void *) value;
970 u_long diff = off;
971 u_long st_value;
972 const Elf_Sym* es;
973 const Elf_Sym* best = 0;
974 int i;
975
976 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
977 if (es->st_name == 0)
978 continue;
979 st_value = es->st_value + (uintptr_t) (void *) ef->address;
980 if (off >= st_value) {
981 if (off - st_value < diff) {
982 diff = off - st_value;
983 best = es;
984 if (diff == 0)
985 break;
986 } else if (off - st_value == diff) {
987 best = es;
988 }
989 }
990 }
991 if (best == 0)
992 *diffp = off;
993 else
994 *diffp = diff;
995 *sym = (c_linker_sym_t) best;
996
997 return 0;
998 }
999
1000 /*
1001 * Look up a linker set on an ELF system.
1002 */
1003 static int
1004 link_elf_lookup_set(linker_file_t lf, const char *name,
1005 void ***startp, void ***stopp, int *countp)
1006 {
1007 c_linker_sym_t sym;
1008 linker_symval_t symval;
1009 char *setsym;
1010 void **start, **stop;
1011 int len, error = 0, count;
1012
1013 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1014 setsym = kmalloc(len, M_LINKER, M_WAITOK);
1015 if (setsym == NULL)
1016 return ENOMEM;
1017
1018 /* get address of first entry */
1019 ksnprintf(setsym, len, "%s%s", "__start_set_", name);
1020 error = link_elf_lookup_symbol(lf, setsym, &sym);
1021 if (error)
1022 goto out;
1023 link_elf_symbol_values(lf, sym, &symval);
1024 if (symval.value == 0) {
1025 error = ESRCH;
1026 goto out;
1027 }
1028 start = (void **)symval.value;
1029
1030 /* get address of last entry */
1031 ksnprintf(setsym, len, "%s%s", "__stop_set_", name);
1032 error = link_elf_lookup_symbol(lf, setsym, &sym);
1033 if (error)
1034 goto out;
1035 link_elf_symbol_values(lf, sym, &symval);
1036 if (symval.value == 0) {
1037 error = ESRCH;
1038 goto out;
1039 }
1040 stop = (void **)symval.value;
1041
1042 /* and the number of entries */
1043 count = stop - start;
1044
1045 /* and copy out */
1046 if (startp)
1047 *startp = start;
1048 if (stopp)
1049 *stopp = stop;
1050 if (countp)
1051 *countp = count;
1052
1053 out:
1054 kfree(setsym, M_LINKER);
1055 return error;
1056 }
1057
DragonFly BSD