2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1998-2000 Doug Rabson
5 * Copyright (c) 2004 Peter Wemm
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/mount.h>
43 #include <sys/namei.h>
44 #include <sys/fcntl.h>
45 #include <sys/vnode.h>
46 #include <sys/linker.h>
48 #include <machine/elf.h>
52 #include <security/mac/mac_framework.h>
55 #include <vm/vm_param.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_kern.h>
58 #include <vm/vm_extern.h>
60 #include <vm/vm_map.h>
62 #include <sys/link_elf.h>
65 #include <contrib/zlib/zlib.h>
68 #include "linker_if.h"
73 int flags; /* Section flags. */
74 int sec; /* Original section number. */
91 typedef struct elf_file {
92 struct linker_file lf; /* Common fields */
95 caddr_t address; /* Relocation address */
96 vm_object_t object; /* VM object to hold file pages */
102 Elf_relaent *relatab;
108 Elf_Sym *ddbsymtab; /* The symbol table we are using */
109 long ddbsymcnt; /* Number of symbols */
110 caddr_t ddbstrtab; /* String table */
111 long ddbstrcnt; /* number of bytes in string table */
113 caddr_t shstrtab; /* Section name string table */
114 long shstrcnt; /* number of bytes in string table */
116 caddr_t ctftab; /* CTF table */
117 long ctfcnt; /* number of bytes in CTF table */
118 caddr_t ctfoff; /* CTF offset table */
119 caddr_t typoff; /* Type offset table */
120 long typlen; /* Number of type entries. */
124 #include <kern/kern_ctf.c>
126 static int link_elf_link_preload(linker_class_t cls,
127 const char *, linker_file_t *);
128 static int link_elf_link_preload_finish(linker_file_t);
129 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *);
130 static int link_elf_lookup_symbol(linker_file_t, const char *,
132 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
134 static int link_elf_search_symbol(linker_file_t, caddr_t value,
135 c_linker_sym_t *sym, long *diffp);
137 static void link_elf_unload_file(linker_file_t);
138 static int link_elf_lookup_set(linker_file_t, const char *,
139 void ***, void ***, int *);
140 static int link_elf_each_function_name(linker_file_t,
141 int (*)(const char *, void *), void *);
142 static int link_elf_each_function_nameval(linker_file_t,
143 linker_function_nameval_callback_t,
145 static int link_elf_reloc_local(linker_file_t, bool);
146 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
147 static long link_elf_strtab_get(linker_file_t, caddr_t *);
149 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
152 static kobj_method_t link_elf_methods[] = {
153 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
154 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
155 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
156 KOBJMETHOD(linker_unload, link_elf_unload_file),
157 KOBJMETHOD(linker_load_file, link_elf_load_file),
158 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
159 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
160 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
161 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
162 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
163 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
164 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
165 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
169 static struct linker_class link_elf_class = {
170 #if ELF_TARG_CLASS == ELFCLASS32
175 link_elf_methods, sizeof(struct elf_file)
178 static int relocate_file(elf_file_t ef);
179 static void elf_obj_cleanup_globals_cache(elf_file_t);
182 link_elf_error(const char *filename, const char *s)
184 if (filename == NULL)
185 printf("kldload: %s\n", s);
187 printf("kldload: %s: %s\n", filename, s);
191 link_elf_init(void *arg)
194 linker_add_class(&link_elf_class);
196 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);
199 link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end,
204 KASSERT(start <= end && start >= (vm_offset_t)ef->address &&
205 end <= round_page((vm_offset_t)ef->address + ef->lf.size),
206 ("link_elf_protect_range: invalid range %#jx-%#jx",
207 (uintmax_t)start, (uintmax_t)end));
213 error = pmap_change_prot(start, end - start, prot);
215 ("link_elf_protect_range: pmap_change_prot() returned %d",
220 error = vm_map_protect(kernel_map, start, end, prot, FALSE);
221 KASSERT(error == KERN_SUCCESS,
222 ("link_elf_protect_range: vm_map_protect() returned %d", error));
226 * Restrict permissions on linker file memory based on section flags.
227 * Sections need not be page-aligned, so overlap within a page is possible.
230 link_elf_protect(elf_file_t ef)
232 vm_offset_t end, segend, segstart, start;
233 vm_prot_t gapprot, prot, segprot;
237 * If the file was preloaded, the last page may contain other preloaded
238 * data which may need to be writeable. ELF files are always
239 * page-aligned, but other preloaded data, such as entropy or CPU
240 * microcode may be loaded with a smaller alignment.
242 gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ;
244 start = end = (vm_offset_t)ef->address;
246 for (i = 0; i < ef->nprogtab; i++) {
248 * VNET and DPCPU sections have their memory allocated by their
249 * respective subsystems.
251 if (ef->progtab[i].name != NULL && (
253 strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 ||
255 strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0))
258 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr);
259 segend = round_page((vm_offset_t)ef->progtab[i].addr +
260 ef->progtab[i].size);
261 segprot = VM_PROT_READ;
262 if ((ef->progtab[i].flags & SHF_WRITE) != 0)
263 segprot |= VM_PROT_WRITE;
264 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0)
265 segprot |= VM_PROT_EXECUTE;
267 if (end <= segstart) {
269 * Case 1: there is no overlap between the previous
270 * segment and this one. Apply protections to the
271 * previous segment, and protect the gap between the
272 * previous and current segments, if any.
274 link_elf_protect_range(ef, start, end, prot);
275 link_elf_protect_range(ef, end, segstart, gapprot);
280 } else if (start < segstart && end == segend) {
282 * Case 2: the current segment is a subrange of the
283 * previous segment. Apply protections to the
284 * non-overlapping portion of the previous segment.
286 link_elf_protect_range(ef, start, segstart, prot);
290 } else if (end < segend) {
292 * Case 3: there is partial overlap between the previous
293 * and current segments. Apply protections to the
294 * non-overlapping portion of the previous segment, and
295 * then the overlap, which must use the union of the two
296 * segments' protections.
298 link_elf_protect_range(ef, start, segstart, prot);
299 link_elf_protect_range(ef, segstart, end,
306 * Case 4: the two segments reside in the same page.
313 * Fix up the last unprotected segment and trailing data.
315 link_elf_protect_range(ef, start, end, prot);
316 link_elf_protect_range(ef, end,
317 round_page((vm_offset_t)ef->address + ef->lf.size), gapprot);
321 link_elf_link_preload(linker_class_t cls, const char *filename,
322 linker_file_t *result)
327 void *modptr, *baseptr, *sizeptr;
332 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
334 /* Look to see if we have the file preloaded */
335 modptr = preload_search_by_name(filename);
339 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
340 baseptr = preload_search_info(modptr, MODINFO_ADDR);
341 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
342 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
344 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
346 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
347 " obj module") != 0 &&
348 strcmp(type, "elf obj module") != 0)) {
351 if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
355 lf = linker_make_file(filename, &link_elf_class);
361 ef->address = *(caddr_t *)baseptr;
362 lf->address = *(caddr_t *)baseptr;
363 lf->size = *(size_t *)sizeptr;
365 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
366 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
367 hdr->e_ident[EI_VERSION] != EV_CURRENT ||
368 hdr->e_version != EV_CURRENT ||
369 hdr->e_type != ET_REL ||
370 hdr->e_machine != ELF_TARG_MACH) {
376 /* Scan the section header for information and table sizing. */
379 for (i = 0; i < hdr->e_shnum; i++) {
380 switch (shdr[i].sh_type) {
384 case SHT_X86_64_UNWIND:
386 /* Ignore sections not loaded by the loader. */
387 if (shdr[i].sh_addr == 0)
393 symstrindex = shdr[i].sh_link;
397 * Ignore relocation tables for sections not
398 * loaded by the loader.
400 if (shdr[shdr[i].sh_info].sh_addr == 0)
405 if (shdr[shdr[i].sh_info].sh_addr == 0)
412 shstrindex = hdr->e_shstrndx;
413 if (ef->nprogtab == 0 || symstrindex < 0 ||
414 symstrindex >= hdr->e_shnum ||
415 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
416 shstrindex >= hdr->e_shnum ||
417 shdr[shstrindex].sh_type != SHT_STRTAB) {
418 printf("%s: bad/missing section headers\n", filename);
423 /* Allocate space for tracking the load chunks */
424 if (ef->nprogtab != 0)
425 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
426 M_LINKER, M_WAITOK | M_ZERO);
427 if (ef->nreltab != 0)
428 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
429 M_LINKER, M_WAITOK | M_ZERO);
430 if (ef->nrelatab != 0)
431 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
432 M_LINKER, M_WAITOK | M_ZERO);
433 if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
434 (ef->nreltab != 0 && ef->reltab == NULL) ||
435 (ef->nrelatab != 0 && ef->relatab == NULL)) {
440 /* XXX, relocate the sh_addr fields saved by the loader. */
442 for (i = 0; i < hdr->e_shnum; i++) {
443 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
444 off = shdr[i].sh_addr;
446 for (i = 0; i < hdr->e_shnum; i++) {
447 if (shdr[i].sh_addr != 0)
448 shdr[i].sh_addr = shdr[i].sh_addr - off +
449 (Elf_Addr)ef->address;
452 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
453 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
454 ef->ddbstrcnt = shdr[symstrindex].sh_size;
455 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
456 ef->shstrcnt = shdr[shstrindex].sh_size;
457 ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
459 /* Now fill out progtab and the relocation tables. */
463 for (i = 0; i < hdr->e_shnum; i++) {
464 switch (shdr[i].sh_type) {
468 case SHT_X86_64_UNWIND:
470 if (shdr[i].sh_addr == 0)
472 ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
473 if (shdr[i].sh_type == SHT_PROGBITS)
474 ef->progtab[pb].name = "<<PROGBITS>>";
476 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
477 ef->progtab[pb].name = "<<UNWIND>>";
480 ef->progtab[pb].name = "<<NOBITS>>";
481 ef->progtab[pb].size = shdr[i].sh_size;
482 ef->progtab[pb].flags = shdr[i].sh_flags;
483 ef->progtab[pb].sec = i;
484 if (ef->shstrtab && shdr[i].sh_name != 0)
485 ef->progtab[pb].name =
486 ef->shstrtab + shdr[i].sh_name;
487 if (ef->progtab[pb].name != NULL &&
488 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
491 dpcpu = dpcpu_alloc(shdr[i].sh_size);
493 printf("%s: pcpu module space is out "
494 "of space; cannot allocate %#jx "
495 "for %s\n", __func__,
496 (uintmax_t)shdr[i].sh_size,
501 memcpy(dpcpu, ef->progtab[pb].addr,
502 ef->progtab[pb].size);
503 dpcpu_copy(dpcpu, shdr[i].sh_size);
504 ef->progtab[pb].addr = dpcpu;
506 } else if (ef->progtab[pb].name != NULL &&
507 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
510 vnet_data = vnet_data_alloc(shdr[i].sh_size);
511 if (vnet_data == NULL) {
512 printf("%s: vnet module space is out "
513 "of space; cannot allocate %#jx "
514 "for %s\n", __func__,
515 (uintmax_t)shdr[i].sh_size,
520 memcpy(vnet_data, ef->progtab[pb].addr,
521 ef->progtab[pb].size);
522 vnet_data_copy(vnet_data, shdr[i].sh_size);
523 ef->progtab[pb].addr = vnet_data;
525 } else if (ef->progtab[pb].name != NULL &&
526 !strcmp(ef->progtab[pb].name, ".ctors")) {
527 lf->ctors_addr = ef->progtab[pb].addr;
528 lf->ctors_size = shdr[i].sh_size;
531 /* Update all symbol values with the offset. */
532 for (j = 0; j < ef->ddbsymcnt; j++) {
533 es = &ef->ddbsymtab[j];
534 if (es->st_shndx != i)
536 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
541 if (shdr[shdr[i].sh_info].sh_addr == 0)
543 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
544 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
545 ef->reltab[rl].sec = shdr[i].sh_info;
549 if (shdr[shdr[i].sh_info].sh_addr == 0)
551 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
552 ef->relatab[ra].nrela =
553 shdr[i].sh_size / sizeof(Elf_Rela);
554 ef->relatab[ra].sec = shdr[i].sh_info;
559 if (pb != ef->nprogtab) {
560 printf("%s: lost progbits\n", filename);
564 if (rl != ef->nreltab) {
565 printf("%s: lost reltab\n", filename);
569 if (ra != ef->nrelatab) {
570 printf("%s: lost relatab\n", filename);
576 * The file needs to be writeable and executable while applying
577 * relocations. Mapping protections are applied once relocation
578 * processing is complete.
580 link_elf_protect_range(ef, (vm_offset_t)ef->address,
581 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL);
583 /* Local intra-module relocations */
584 error = link_elf_reloc_local(lf, false);
591 /* preload not done this way */
592 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
597 link_elf_invoke_ctors(caddr_t addr, size_t size)
602 if (addr == NULL || size == 0)
604 cnt = size / sizeof(*ctor);
606 for (i = 0; i < cnt; i++) {
613 link_elf_link_preload_finish(linker_file_t lf)
619 error = relocate_file(ef);
623 /* Notify MD code that a module is being loaded. */
624 error = elf_cpu_load_file(lf);
628 #if defined(__i386__) || defined(__amd64__)
630 error = link_elf_reloc_local(lf, true);
635 /* Apply protections now that relocation processing is complete. */
636 link_elf_protect(ef);
638 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
643 link_elf_load_file(linker_class_t cls, const char *filename,
644 linker_file_t *result)
646 struct nameidata *nd;
647 struct thread *td = curthread; /* XXX */
671 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
672 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
674 error = vn_open(nd, &flags, 0, NULL);
679 NDFREE(nd, NDF_ONLY_PNBUF);
680 if (nd->ni_vp->v_type != VREG) {
685 error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
691 /* Read the elf header from the file. */
692 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
693 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
694 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
708 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
709 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
710 link_elf_error(filename, "Unsupported file layout");
714 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
715 || hdr->e_version != EV_CURRENT) {
716 link_elf_error(filename, "Unsupported file version");
720 if (hdr->e_type != ET_REL) {
724 if (hdr->e_machine != ELF_TARG_MACH) {
725 link_elf_error(filename, "Unsupported machine");
730 lf = linker_make_file(filename, &link_elf_class);
735 ef = (elf_file_t) lf;
741 /* Allocate and read in the section header */
742 nbytes = hdr->e_shnum * hdr->e_shentsize;
743 if (nbytes == 0 || hdr->e_shoff == 0 ||
744 hdr->e_shentsize != sizeof(Elf_Shdr)) {
748 shdr = malloc(nbytes, M_LINKER, M_WAITOK);
750 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
751 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
760 /* Scan the section header for information and table sizing. */
764 for (i = 0; i < hdr->e_shnum; i++) {
765 if (shdr[i].sh_size == 0)
767 switch (shdr[i].sh_type) {
771 case SHT_X86_64_UNWIND:
773 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
780 symstrindex = shdr[i].sh_link;
784 * Ignore relocation tables for unallocated
787 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
792 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
800 if (ef->nprogtab == 0) {
801 link_elf_error(filename, "file has no contents");
806 /* Only allow one symbol table for now */
807 link_elf_error(filename,
808 "file must have exactly one symbol table");
812 if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
813 shdr[symstrindex].sh_type != SHT_STRTAB) {
814 link_elf_error(filename, "file has invalid symbol strings");
819 /* Allocate space for tracking the load chunks */
820 if (ef->nprogtab != 0)
821 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
822 M_LINKER, M_WAITOK | M_ZERO);
823 if (ef->nreltab != 0)
824 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
825 M_LINKER, M_WAITOK | M_ZERO);
826 if (ef->nrelatab != 0)
827 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
828 M_LINKER, M_WAITOK | M_ZERO);
830 if (symtabindex == -1) {
831 link_elf_error(filename, "lost symbol table index");
835 /* Allocate space for and load the symbol table */
836 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
837 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
838 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
839 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
840 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
849 /* Allocate space for and load the symbol strings */
850 ef->ddbstrcnt = shdr[symstrindex].sh_size;
851 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
852 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
853 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
854 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
863 /* Do we have a string table for the section names? */
865 if (hdr->e_shstrndx != 0 &&
866 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
867 shstrindex = hdr->e_shstrndx;
868 ef->shstrcnt = shdr[shstrindex].sh_size;
869 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
871 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
872 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
873 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
883 /* Size up code/data(progbits) and bss(nobits). */
885 for (i = 0; i < hdr->e_shnum; i++) {
886 if (shdr[i].sh_size == 0)
888 switch (shdr[i].sh_type) {
892 case SHT_X86_64_UNWIND:
894 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
896 alignmask = shdr[i].sh_addralign - 1;
897 mapsize += alignmask;
898 mapsize &= ~alignmask;
899 mapsize += shdr[i].sh_size;
905 * We know how much space we need for the text/data/bss/etc.
906 * This stuff needs to be in a single chunk so that profiling etc
907 * can get the bounds and gdb can associate offsets with modules
909 ef->object = vm_object_allocate(OBJT_PHYS, atop(round_page(mapsize)));
910 if (ef->object == NULL) {
916 * In order to satisfy amd64's architectural requirements on the
917 * location of code and data in the kernel's address space, request a
918 * mapping that is above the kernel.
920 * Protections will be restricted once relocations are applied.
925 mapbase = VM_MIN_KERNEL_ADDRESS;
927 error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
928 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
930 if (error != KERN_SUCCESS) {
931 vm_object_deallocate(ef->object);
938 error = vm_map_wire(kernel_map, mapbase,
939 mapbase + round_page(mapsize),
940 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
941 if (error != KERN_SUCCESS) {
946 /* Inform the kld system about the situation */
947 lf->address = ef->address = (caddr_t)mapbase;
951 * Now load code/data(progbits), zero bss(nobits), allocate space for
958 for (i = 0; i < hdr->e_shnum; i++) {
959 if (shdr[i].sh_size == 0)
961 switch (shdr[i].sh_type) {
965 case SHT_X86_64_UNWIND:
967 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
969 alignmask = shdr[i].sh_addralign - 1;
970 mapbase += alignmask;
971 mapbase &= ~alignmask;
972 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
973 ef->progtab[pb].name =
974 ef->shstrtab + shdr[i].sh_name;
975 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
976 lf->ctors_addr = (caddr_t)mapbase;
977 lf->ctors_size = shdr[i].sh_size;
979 } else if (shdr[i].sh_type == SHT_PROGBITS)
980 ef->progtab[pb].name = "<<PROGBITS>>";
982 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
983 ef->progtab[pb].name = "<<UNWIND>>";
986 ef->progtab[pb].name = "<<NOBITS>>";
987 if (ef->progtab[pb].name != NULL &&
988 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
989 ef->progtab[pb].addr =
990 dpcpu_alloc(shdr[i].sh_size);
991 if (ef->progtab[pb].addr == NULL) {
992 printf("%s: pcpu module space is out "
993 "of space; cannot allocate %#jx "
994 "for %s\n", __func__,
995 (uintmax_t)shdr[i].sh_size,
1000 else if (ef->progtab[pb].name != NULL &&
1001 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
1002 ef->progtab[pb].addr =
1003 vnet_data_alloc(shdr[i].sh_size);
1004 if (ef->progtab[pb].addr == NULL) {
1005 printf("%s: vnet module space is out "
1006 "of space; cannot allocate %#jx "
1007 "for %s\n", __func__,
1008 (uintmax_t)shdr[i].sh_size,
1014 ef->progtab[pb].addr =
1015 (void *)(uintptr_t)mapbase;
1016 if (ef->progtab[pb].addr == NULL) {
1020 ef->progtab[pb].size = shdr[i].sh_size;
1021 ef->progtab[pb].flags = shdr[i].sh_flags;
1022 ef->progtab[pb].sec = i;
1023 if (shdr[i].sh_type == SHT_PROGBITS
1025 || shdr[i].sh_type == SHT_X86_64_UNWIND
1028 error = vn_rdwr(UIO_READ, nd->ni_vp,
1029 ef->progtab[pb].addr,
1030 shdr[i].sh_size, shdr[i].sh_offset,
1031 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
1032 NOCRED, &resid, td);
1039 /* Initialize the per-cpu or vnet area. */
1040 if (ef->progtab[pb].addr != (void *)mapbase &&
1041 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
1042 dpcpu_copy(ef->progtab[pb].addr,
1045 else if (ef->progtab[pb].addr !=
1047 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
1048 vnet_data_copy(ef->progtab[pb].addr,
1052 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
1054 /* Update all symbol values with the offset. */
1055 for (j = 0; j < ef->ddbsymcnt; j++) {
1056 es = &ef->ddbsymtab[j];
1057 if (es->st_shndx != i)
1059 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
1061 mapbase += shdr[i].sh_size;
1065 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1067 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
1069 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
1070 ef->reltab[rl].sec = shdr[i].sh_info;
1071 error = vn_rdwr(UIO_READ, nd->ni_vp,
1072 (void *)ef->reltab[rl].rel,
1073 shdr[i].sh_size, shdr[i].sh_offset,
1074 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1085 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1087 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
1089 ef->relatab[ra].nrela =
1090 shdr[i].sh_size / sizeof(Elf_Rela);
1091 ef->relatab[ra].sec = shdr[i].sh_info;
1092 error = vn_rdwr(UIO_READ, nd->ni_vp,
1093 (void *)ef->relatab[ra].rela,
1094 shdr[i].sh_size, shdr[i].sh_offset,
1095 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1107 if (pb != ef->nprogtab) {
1108 link_elf_error(filename, "lost progbits");
1112 if (rl != ef->nreltab) {
1113 link_elf_error(filename, "lost reltab");
1117 if (ra != ef->nrelatab) {
1118 link_elf_error(filename, "lost relatab");
1122 if (mapbase != (vm_offset_t)ef->address + mapsize) {
1124 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
1125 filename != NULL ? filename : "<none>",
1126 (u_long)mapbase, ef->address, (u_long)mapsize,
1127 (u_long)(vm_offset_t)ef->address + mapsize);
1132 /* Local intra-module relocations */
1133 error = link_elf_reloc_local(lf, false);
1137 /* Pull in dependencies */
1138 VOP_UNLOCK(nd->ni_vp, 0);
1139 error = linker_load_dependencies(lf);
1140 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
1144 /* External relocations */
1145 error = relocate_file(ef);
1149 /* Notify MD code that a module is being loaded. */
1150 error = elf_cpu_load_file(lf);
1154 #if defined(__i386__) || defined(__amd64__)
1156 error = link_elf_reloc_local(lf, true);
1161 link_elf_protect(ef);
1162 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
1166 VOP_UNLOCK(nd->ni_vp, 0);
1167 vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1170 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1171 free(hdr, M_LINKER);
1177 link_elf_unload_file(linker_file_t file)
1179 elf_file_t ef = (elf_file_t) file;
1182 /* Notify MD code that a module is being unloaded. */
1183 elf_cpu_unload_file(file);
1186 for (i = 0; i < ef->nprogtab; i++) {
1187 if (ef->progtab[i].size == 0)
1189 if (ef->progtab[i].name == NULL)
1191 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1192 dpcpu_free(ef->progtab[i].addr,
1193 ef->progtab[i].size);
1195 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1196 vnet_data_free(ef->progtab[i].addr,
1197 ef->progtab[i].size);
1201 if (ef->preloaded) {
1202 free(ef->reltab, M_LINKER);
1203 free(ef->relatab, M_LINKER);
1204 free(ef->progtab, M_LINKER);
1205 free(ef->ctftab, M_LINKER);
1206 free(ef->ctfoff, M_LINKER);
1207 free(ef->typoff, M_LINKER);
1208 if (file->pathname != NULL)
1209 preload_delete_name(file->pathname);
1213 for (i = 0; i < ef->nreltab; i++)
1214 free(ef->reltab[i].rel, M_LINKER);
1215 for (i = 0; i < ef->nrelatab; i++)
1216 free(ef->relatab[i].rela, M_LINKER);
1217 free(ef->reltab, M_LINKER);
1218 free(ef->relatab, M_LINKER);
1219 free(ef->progtab, M_LINKER);
1221 if (ef->object != NULL)
1222 vm_map_remove(kernel_map, (vm_offset_t)ef->address,
1223 (vm_offset_t)ef->address + ptoa(ef->object->size));
1224 free(ef->e_shdr, M_LINKER);
1225 free(ef->ddbsymtab, M_LINKER);
1226 free(ef->ddbstrtab, M_LINKER);
1227 free(ef->shstrtab, M_LINKER);
1228 free(ef->ctftab, M_LINKER);
1229 free(ef->ctfoff, M_LINKER);
1230 free(ef->typoff, M_LINKER);
1234 symbol_name(elf_file_t ef, Elf_Size r_info)
1238 if (ELF_R_SYM(r_info)) {
1239 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1240 return ef->ddbstrtab + ref->st_name;
1246 findbase(elf_file_t ef, int sec)
1251 for (i = 0; i < ef->nprogtab; i++) {
1252 if (sec == ef->progtab[i].sec) {
1253 base = (Elf_Addr)ef->progtab[i].addr;
1261 relocate_file(elf_file_t ef)
1263 const Elf_Rel *rellim;
1265 const Elf_Rela *relalim;
1266 const Elf_Rela *rela;
1267 const char *symname;
1274 /* Perform relocations without addend if there are any: */
1275 for (i = 0; i < ef->nreltab; i++) {
1276 rel = ef->reltab[i].rel;
1278 link_elf_error(ef->lf.filename, "lost a reltab!");
1281 rellim = rel + ef->reltab[i].nrel;
1282 base = findbase(ef, ef->reltab[i].sec);
1284 link_elf_error(ef->lf.filename, "lost base for reltab");
1287 for ( ; rel < rellim; rel++) {
1288 symidx = ELF_R_SYM(rel->r_info);
1289 if (symidx >= ef->ddbsymcnt)
1291 sym = ef->ddbsymtab + symidx;
1292 /* Local relocs are already done */
1293 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1295 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1297 symname = symbol_name(ef, rel->r_info);
1298 printf("link_elf_obj: symbol %s undefined\n",
1305 /* Perform relocations with addend if there are any: */
1306 for (i = 0; i < ef->nrelatab; i++) {
1307 rela = ef->relatab[i].rela;
1309 link_elf_error(ef->lf.filename, "lost a relatab!");
1312 relalim = rela + ef->relatab[i].nrela;
1313 base = findbase(ef, ef->relatab[i].sec);
1315 link_elf_error(ef->lf.filename,
1316 "lost base for relatab");
1319 for ( ; rela < relalim; rela++) {
1320 symidx = ELF_R_SYM(rela->r_info);
1321 if (symidx >= ef->ddbsymcnt)
1323 sym = ef->ddbsymtab + symidx;
1324 /* Local relocs are already done */
1325 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1327 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1329 symname = symbol_name(ef, rela->r_info);
1330 printf("link_elf_obj: symbol %s undefined\n",
1338 * Only clean SHN_FBSD_CACHED for successful return. If we
1339 * modified symbol table for the object but found an
1340 * unresolved symbol, there is no reason to roll back.
1342 elf_obj_cleanup_globals_cache(ef);
1348 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1350 elf_file_t ef = (elf_file_t) lf;
1351 const Elf_Sym *symp;
1355 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1356 strp = ef->ddbstrtab + symp->st_name;
1357 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1358 *sym = (c_linker_sym_t) symp;
1366 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1367 linker_symval_t *symval)
1373 ef = (elf_file_t) lf;
1374 es = (const Elf_Sym*) sym;
1375 val = (caddr_t)es->st_value;
1376 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1377 symval->name = ef->ddbstrtab + es->st_name;
1378 val = (caddr_t)es->st_value;
1379 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1380 val = ((caddr_t (*)(void))val)();
1381 symval->value = val;
1382 symval->size = es->st_size;
1389 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1390 c_linker_sym_t *sym, long *diffp)
1392 elf_file_t ef = (elf_file_t) lf;
1393 u_long off = (uintptr_t) (void *) value;
1397 const Elf_Sym *best = NULL;
1400 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1401 if (es->st_name == 0)
1403 st_value = es->st_value;
1404 if (off >= st_value) {
1405 if (off - st_value < diff) {
1406 diff = off - st_value;
1410 } else if (off - st_value == diff) {
1419 *sym = (c_linker_sym_t) best;
1425 * Look up a linker set on an ELF system.
1428 link_elf_lookup_set(linker_file_t lf, const char *name,
1429 void ***startp, void ***stopp, int *countp)
1431 elf_file_t ef = (elf_file_t)lf;
1432 void **start, **stop;
1435 /* Relative to section number */
1436 for (i = 0; i < ef->nprogtab; i++) {
1437 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1438 strcmp(ef->progtab[i].name + 4, name) == 0) {
1439 start = (void **)ef->progtab[i].addr;
1440 stop = (void **)((char *)ef->progtab[i].addr +
1441 ef->progtab[i].size);
1442 count = stop - start;
1456 link_elf_each_function_name(linker_file_t file,
1457 int (*callback)(const char *, void *), void *opaque)
1459 elf_file_t ef = (elf_file_t)file;
1460 const Elf_Sym *symp;
1463 /* Exhaustive search */
1464 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1465 if (symp->st_value != 0 &&
1466 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1467 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1468 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1477 link_elf_each_function_nameval(linker_file_t file,
1478 linker_function_nameval_callback_t callback, void *opaque)
1480 linker_symval_t symval;
1481 elf_file_t ef = (elf_file_t)file;
1482 const Elf_Sym* symp;
1485 /* Exhaustive search */
1486 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1487 if (symp->st_value != 0 &&
1488 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1489 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1490 error = link_elf_symbol_values(file,
1491 (c_linker_sym_t)symp, &symval);
1494 error = callback(file, i, &symval, opaque);
1503 elf_obj_cleanup_globals_cache(elf_file_t ef)
1508 for (i = 0; i < ef->ddbsymcnt; i++) {
1509 sym = ef->ddbsymtab + i;
1510 if (sym->st_shndx == SHN_FBSD_CACHED) {
1511 sym->st_shndx = SHN_UNDEF;
1518 * Symbol lookup function that can be used when the symbol index is known (ie
1519 * in relocations). It uses the symbol index instead of doing a fully fledged
1520 * hash table based lookup when such is valid. For example for local symbols.
1521 * This is not only more efficient, it's also more correct. It's not always
1522 * the case that the symbol can be found through the hash table.
1525 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1527 elf_file_t ef = (elf_file_t)lf;
1532 /* Don't even try to lookup the symbol if the index is bogus. */
1533 if (symidx >= ef->ddbsymcnt) {
1538 sym = ef->ddbsymtab + symidx;
1540 /* Quick answer if there is a definition included. */
1541 if (sym->st_shndx != SHN_UNDEF) {
1542 res1 = (Elf_Addr)sym->st_value;
1543 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1544 res1 = ((Elf_Addr (*)(void))res1)();
1549 /* If we get here, then it is undefined and needs a lookup. */
1550 switch (ELF_ST_BIND(sym->st_info)) {
1552 /* Local, but undefined? huh? */
1558 /* Relative to Data or Function name */
1559 symbol = ef->ddbstrtab + sym->st_name;
1561 /* Force a lookup failure if the symbol name is bogus. */
1566 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1569 * Cache global lookups during module relocation. The failure
1570 * case is particularly expensive for callers, who must scan
1571 * through the entire globals table doing strcmp(). Cache to
1572 * avoid doing such work repeatedly.
1574 * After relocation is complete, undefined globals will be
1575 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1579 sym->st_shndx = SHN_FBSD_CACHED;
1580 sym->st_value = res1;
1583 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1596 link_elf_fix_link_set(elf_file_t ef)
1598 static const char startn[] = "__start_";
1599 static const char stopn[] = "__stop_";
1601 const char *sym_name, *linkset_name;
1602 Elf_Addr startp, stopp;
1607 for (symidx = 1 /* zero entry is special */;
1608 symidx < ef->ddbsymcnt; symidx++) {
1609 sym = ef->ddbsymtab + symidx;
1610 if (sym->st_shndx != SHN_UNDEF)
1613 sym_name = ef->ddbstrtab + sym->st_name;
1614 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1616 linkset_name = sym_name + sizeof(startn) - 1;
1618 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1620 linkset_name = sym_name + sizeof(stopn) - 1;
1625 for (i = 0; i < ef->nprogtab; i++) {
1626 if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1627 startp = (Elf_Addr)ef->progtab[i].addr;
1628 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1632 if (i == ef->nprogtab)
1635 sym->st_value = start ? startp : stopp;
1641 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1643 elf_file_t ef = (elf_file_t)lf;
1644 const Elf_Rel *rellim;
1646 const Elf_Rela *relalim;
1647 const Elf_Rela *rela;
1653 link_elf_fix_link_set(ef);
1655 /* Perform relocations without addend if there are any: */
1656 for (i = 0; i < ef->nreltab; i++) {
1657 rel = ef->reltab[i].rel;
1659 link_elf_error(ef->lf.filename, "lost a reltab");
1662 rellim = rel + ef->reltab[i].nrel;
1663 base = findbase(ef, ef->reltab[i].sec);
1665 link_elf_error(ef->lf.filename, "lost base for reltab");
1668 for ( ; rel < rellim; rel++) {
1669 symidx = ELF_R_SYM(rel->r_info);
1670 if (symidx >= ef->ddbsymcnt)
1672 sym = ef->ddbsymtab + symidx;
1673 /* Only do local relocs */
1674 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1676 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1677 elf_is_ifunc_reloc(rel->r_info)) == ifuncs)
1678 elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1683 /* Perform relocations with addend if there are any: */
1684 for (i = 0; i < ef->nrelatab; i++) {
1685 rela = ef->relatab[i].rela;
1687 link_elf_error(ef->lf.filename, "lost a relatab!");
1690 relalim = rela + ef->relatab[i].nrela;
1691 base = findbase(ef, ef->relatab[i].sec);
1693 link_elf_error(ef->lf.filename, "lost base for reltab");
1696 for ( ; rela < relalim; rela++) {
1697 symidx = ELF_R_SYM(rela->r_info);
1698 if (symidx >= ef->ddbsymcnt)
1700 sym = ef->ddbsymtab + symidx;
1701 /* Only do local relocs */
1702 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1704 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1705 elf_is_ifunc_reloc(rela->r_info)) == ifuncs)
1706 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1714 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1716 elf_file_t ef = (elf_file_t)lf;
1718 *symtab = ef->ddbsymtab;
1720 if (*symtab == NULL)
1723 return (ef->ddbsymcnt);
1727 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1729 elf_file_t ef = (elf_file_t)lf;
1731 *strtab = ef->ddbstrtab;
1733 if (*strtab == NULL)
1736 return (ef->ddbstrcnt);