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/fcntl.h>
38 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/linker.h>
42 #include <sys/mutex.h>
43 #include <sys/mount.h>
44 #include <sys/namei.h>
46 #include <sys/rwlock.h>
47 #include <sys/vnode.h>
49 #include <machine/elf.h>
53 #include <security/mac/mac_framework.h>
56 #include <vm/vm_param.h>
58 #include <vm/vm_extern.h>
59 #include <vm/vm_kern.h>
60 #include <vm/vm_map.h>
61 #include <vm/vm_object.h>
62 #include <vm/vm_page.h>
63 #include <vm/vm_pager.h>
65 #include <sys/link_elf.h>
68 #include <contrib/zlib/zlib.h>
71 #include "linker_if.h"
76 int flags; /* Section flags. */
77 int sec; /* Original section number. */
93 typedef struct elf_file {
94 struct linker_file lf; /* Common fields */
97 caddr_t address; /* Relocation address */
98 vm_object_t object; /* VM object to hold file pages */
101 Elf_progent *progtab;
104 Elf_relaent *relatab;
110 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 */
115 caddr_t shstrtab; /* Section name string table */
116 long shstrcnt; /* number of bytes in string table */
118 caddr_t ctftab; /* CTF table */
119 long ctfcnt; /* number of bytes in CTF table */
120 caddr_t ctfoff; /* CTF offset table */
121 caddr_t typoff; /* Type offset table */
122 long typlen; /* Number of type entries. */
126 #include <kern/kern_ctf.c>
128 static int link_elf_link_preload(linker_class_t cls,
129 const char *, linker_file_t *);
130 static int link_elf_link_preload_finish(linker_file_t);
131 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *);
132 static int link_elf_lookup_symbol(linker_file_t, const char *,
134 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
136 static int link_elf_search_symbol(linker_file_t, caddr_t value,
137 c_linker_sym_t *sym, long *diffp);
139 static void link_elf_unload_file(linker_file_t);
140 static int link_elf_lookup_set(linker_file_t, const char *,
141 void ***, void ***, int *);
142 static int link_elf_each_function_name(linker_file_t,
143 int (*)(const char *, void *), void *);
144 static int link_elf_each_function_nameval(linker_file_t,
145 linker_function_nameval_callback_t,
147 static int link_elf_reloc_local(linker_file_t, bool);
148 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
149 static long link_elf_strtab_get(linker_file_t, caddr_t *);
151 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
154 static kobj_method_t link_elf_methods[] = {
155 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
156 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
157 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
158 KOBJMETHOD(linker_unload, link_elf_unload_file),
159 KOBJMETHOD(linker_load_file, link_elf_load_file),
160 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
161 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
162 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
163 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
164 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
165 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
166 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
167 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
171 static struct linker_class link_elf_class = {
172 #if ELF_TARG_CLASS == ELFCLASS32
177 link_elf_methods, sizeof(struct elf_file)
180 static int relocate_file(elf_file_t ef);
181 static void elf_obj_cleanup_globals_cache(elf_file_t);
184 link_elf_error(const char *filename, const char *s)
186 if (filename == NULL)
187 printf("kldload: %s\n", s);
189 printf("kldload: %s: %s\n", filename, s);
193 link_elf_init(void *arg)
196 linker_add_class(&link_elf_class);
198 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);
201 link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end,
206 KASSERT(start <= end && start >= (vm_offset_t)ef->address &&
207 end <= round_page((vm_offset_t)ef->address + ef->lf.size),
208 ("link_elf_protect_range: invalid range %#jx-%#jx",
209 (uintmax_t)start, (uintmax_t)end));
215 error = pmap_change_prot(start, end - start, prot);
217 ("link_elf_protect_range: pmap_change_prot() returned %d",
222 error = vm_map_protect(kernel_map, start, end, prot, 0,
223 VM_MAP_PROTECT_SET_PROT);
224 KASSERT(error == KERN_SUCCESS,
225 ("link_elf_protect_range: vm_map_protect() returned %d", error));
229 * Restrict permissions on linker file memory based on section flags.
230 * Sections need not be page-aligned, so overlap within a page is possible.
233 link_elf_protect(elf_file_t ef)
235 vm_offset_t end, segend, segstart, start;
236 vm_prot_t gapprot, prot, segprot;
240 * If the file was preloaded, the last page may contain other preloaded
241 * data which may need to be writeable. ELF files are always
242 * page-aligned, but other preloaded data, such as entropy or CPU
243 * microcode may be loaded with a smaller alignment.
245 gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ;
247 start = end = (vm_offset_t)ef->address;
249 for (i = 0; i < ef->nprogtab; i++) {
251 * VNET and DPCPU sections have their memory allocated by their
252 * respective subsystems.
254 if (ef->progtab[i].name != NULL && (
256 strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 ||
258 strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0))
261 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr);
262 segend = round_page((vm_offset_t)ef->progtab[i].addr +
263 ef->progtab[i].size);
264 segprot = VM_PROT_READ;
265 if ((ef->progtab[i].flags & SHF_WRITE) != 0)
266 segprot |= VM_PROT_WRITE;
267 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0)
268 segprot |= VM_PROT_EXECUTE;
270 if (end <= segstart) {
272 * Case 1: there is no overlap between the previous
273 * segment and this one. Apply protections to the
274 * previous segment, and protect the gap between the
275 * previous and current segments, if any.
277 link_elf_protect_range(ef, start, end, prot);
278 link_elf_protect_range(ef, end, segstart, gapprot);
283 } else if (start < segstart && end == segend) {
285 * Case 2: the current segment is a subrange of the
286 * previous segment. Apply protections to the
287 * non-overlapping portion of the previous segment.
289 link_elf_protect_range(ef, start, segstart, prot);
293 } else if (end < segend) {
295 * Case 3: there is partial overlap between the previous
296 * and current segments. Apply protections to the
297 * non-overlapping portion of the previous segment, and
298 * then the overlap, which must use the union of the two
299 * segments' protections.
301 link_elf_protect_range(ef, start, segstart, prot);
302 link_elf_protect_range(ef, segstart, end,
309 * Case 4: the two segments reside in the same page.
316 * Fix up the last unprotected segment and trailing data.
318 link_elf_protect_range(ef, start, end, prot);
319 link_elf_protect_range(ef, end,
320 round_page((vm_offset_t)ef->address + ef->lf.size), gapprot);
324 link_elf_link_preload(linker_class_t cls, const char *filename,
325 linker_file_t *result)
330 void *modptr, *baseptr, *sizeptr;
335 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
337 /* Look to see if we have the file preloaded */
338 modptr = preload_search_by_name(filename);
342 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
343 baseptr = preload_search_info(modptr, MODINFO_ADDR);
344 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
345 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
347 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
349 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
350 " obj module") != 0 &&
351 strcmp(type, "elf obj module") != 0)) {
354 if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
358 lf = linker_make_file(filename, &link_elf_class);
364 ef->address = *(caddr_t *)baseptr;
365 lf->address = *(caddr_t *)baseptr;
366 lf->size = *(size_t *)sizeptr;
368 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
369 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
370 hdr->e_ident[EI_VERSION] != EV_CURRENT ||
371 hdr->e_version != EV_CURRENT ||
372 hdr->e_type != ET_REL ||
373 hdr->e_machine != ELF_TARG_MACH) {
379 /* Scan the section header for information and table sizing. */
382 for (i = 0; i < hdr->e_shnum; i++) {
383 switch (shdr[i].sh_type) {
387 case SHT_X86_64_UNWIND:
391 /* Ignore sections not loaded by the loader. */
392 if (shdr[i].sh_addr == 0)
398 symstrindex = shdr[i].sh_link;
402 * Ignore relocation tables for sections not
403 * loaded by the loader.
405 if (shdr[shdr[i].sh_info].sh_addr == 0)
410 if (shdr[shdr[i].sh_info].sh_addr == 0)
417 shstrindex = hdr->e_shstrndx;
418 if (ef->nprogtab == 0 || symstrindex < 0 ||
419 symstrindex >= hdr->e_shnum ||
420 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
421 shstrindex >= hdr->e_shnum ||
422 shdr[shstrindex].sh_type != SHT_STRTAB) {
423 printf("%s: bad/missing section headers\n", filename);
428 /* Allocate space for tracking the load chunks */
429 if (ef->nprogtab != 0)
430 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
431 M_LINKER, M_WAITOK | M_ZERO);
432 if (ef->nreltab != 0)
433 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
434 M_LINKER, M_WAITOK | M_ZERO);
435 if (ef->nrelatab != 0)
436 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
437 M_LINKER, M_WAITOK | M_ZERO);
438 if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
439 (ef->nreltab != 0 && ef->reltab == NULL) ||
440 (ef->nrelatab != 0 && ef->relatab == NULL)) {
445 /* XXX, relocate the sh_addr fields saved by the loader. */
447 for (i = 0; i < hdr->e_shnum; i++) {
448 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
449 off = shdr[i].sh_addr;
451 for (i = 0; i < hdr->e_shnum; i++) {
452 if (shdr[i].sh_addr != 0)
453 shdr[i].sh_addr = shdr[i].sh_addr - off +
454 (Elf_Addr)ef->address;
457 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
458 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
459 ef->ddbstrcnt = shdr[symstrindex].sh_size;
460 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
461 ef->shstrcnt = shdr[shstrindex].sh_size;
462 ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
464 /* Now fill out progtab and the relocation tables. */
468 for (i = 0; i < hdr->e_shnum; i++) {
469 switch (shdr[i].sh_type) {
473 case SHT_X86_64_UNWIND:
477 if (shdr[i].sh_addr == 0)
479 ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
480 if (shdr[i].sh_type == SHT_PROGBITS)
481 ef->progtab[pb].name = "<<PROGBITS>>";
483 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
484 ef->progtab[pb].name = "<<UNWIND>>";
486 else if (shdr[i].sh_type == SHT_INIT_ARRAY)
487 ef->progtab[pb].name = "<<INIT_ARRAY>>";
488 else if (shdr[i].sh_type == SHT_FINI_ARRAY)
489 ef->progtab[pb].name = "<<FINI_ARRAY>>";
491 ef->progtab[pb].name = "<<NOBITS>>";
492 ef->progtab[pb].size = shdr[i].sh_size;
493 ef->progtab[pb].flags = shdr[i].sh_flags;
494 ef->progtab[pb].sec = i;
495 if (ef->shstrtab && shdr[i].sh_name != 0)
496 ef->progtab[pb].name =
497 ef->shstrtab + shdr[i].sh_name;
498 if (ef->progtab[pb].name != NULL &&
499 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
502 dpcpu = dpcpu_alloc(shdr[i].sh_size);
504 printf("%s: pcpu module space is out "
505 "of space; cannot allocate %#jx "
506 "for %s\n", __func__,
507 (uintmax_t)shdr[i].sh_size,
512 memcpy(dpcpu, ef->progtab[pb].addr,
513 ef->progtab[pb].size);
514 dpcpu_copy(dpcpu, shdr[i].sh_size);
515 ef->progtab[pb].addr = dpcpu;
517 } else if (ef->progtab[pb].name != NULL &&
518 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
521 vnet_data = vnet_data_alloc(shdr[i].sh_size);
522 if (vnet_data == NULL) {
523 printf("%s: vnet module space is out "
524 "of space; cannot allocate %#jx "
525 "for %s\n", __func__,
526 (uintmax_t)shdr[i].sh_size,
531 memcpy(vnet_data, ef->progtab[pb].addr,
532 ef->progtab[pb].size);
533 vnet_data_copy(vnet_data, shdr[i].sh_size);
534 ef->progtab[pb].addr = vnet_data;
536 } else if ((ef->progtab[pb].name != NULL &&
537 strcmp(ef->progtab[pb].name, ".ctors") == 0) ||
538 shdr[i].sh_type == SHT_INIT_ARRAY) {
539 if (lf->ctors_addr != 0) {
541 "%s: multiple ctor sections in %s\n",
544 lf->ctors_addr = ef->progtab[pb].addr;
545 lf->ctors_size = shdr[i].sh_size;
549 /* Update all symbol values with the offset. */
550 for (j = 0; j < ef->ddbsymcnt; j++) {
551 es = &ef->ddbsymtab[j];
552 if (es->st_shndx != i)
554 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
559 if (shdr[shdr[i].sh_info].sh_addr == 0)
561 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
562 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
563 ef->reltab[rl].sec = shdr[i].sh_info;
567 if (shdr[shdr[i].sh_info].sh_addr == 0)
569 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
570 ef->relatab[ra].nrela =
571 shdr[i].sh_size / sizeof(Elf_Rela);
572 ef->relatab[ra].sec = shdr[i].sh_info;
577 if (pb != ef->nprogtab) {
578 printf("%s: lost progbits\n", filename);
582 if (rl != ef->nreltab) {
583 printf("%s: lost reltab\n", filename);
587 if (ra != ef->nrelatab) {
588 printf("%s: lost relatab\n", filename);
594 * The file needs to be writeable and executable while applying
595 * relocations. Mapping protections are applied once relocation
596 * processing is complete.
598 link_elf_protect_range(ef, (vm_offset_t)ef->address,
599 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL);
601 /* Local intra-module relocations */
602 error = link_elf_reloc_local(lf, false);
609 /* preload not done this way */
610 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
615 link_elf_invoke_ctors(caddr_t addr, size_t size)
620 if (addr == NULL || size == 0)
622 cnt = size / sizeof(*ctor);
624 for (i = 0; i < cnt; i++) {
631 link_elf_link_preload_finish(linker_file_t lf)
637 error = relocate_file(ef);
641 /* Notify MD code that a module is being loaded. */
642 error = elf_cpu_load_file(lf);
646 #if defined(__i386__) || defined(__amd64__)
648 error = link_elf_reloc_local(lf, true);
653 /* Apply protections now that relocation processing is complete. */
654 link_elf_protect(ef);
656 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
661 link_elf_load_file(linker_class_t cls, const char *filename,
662 linker_file_t *result)
664 struct nameidata *nd;
665 struct thread *td = curthread; /* XXX */
689 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
690 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
692 error = vn_open(nd, &flags, 0, NULL);
697 NDFREE(nd, NDF_ONLY_PNBUF);
698 if (nd->ni_vp->v_type != VREG) {
703 error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
709 /* Read the elf header from the file. */
710 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
711 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
712 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
726 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
727 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
728 link_elf_error(filename, "Unsupported file layout");
732 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
733 || hdr->e_version != EV_CURRENT) {
734 link_elf_error(filename, "Unsupported file version");
738 if (hdr->e_type != ET_REL) {
742 if (hdr->e_machine != ELF_TARG_MACH) {
743 link_elf_error(filename, "Unsupported machine");
748 lf = linker_make_file(filename, &link_elf_class);
753 ef = (elf_file_t) lf;
759 /* Allocate and read in the section header */
760 nbytes = hdr->e_shnum * hdr->e_shentsize;
761 if (nbytes == 0 || hdr->e_shoff == 0 ||
762 hdr->e_shentsize != sizeof(Elf_Shdr)) {
766 shdr = malloc(nbytes, M_LINKER, M_WAITOK);
768 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
769 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
778 /* Scan the section header for information and table sizing. */
782 for (i = 0; i < hdr->e_shnum; i++) {
783 if (shdr[i].sh_size == 0)
785 switch (shdr[i].sh_type) {
789 case SHT_X86_64_UNWIND:
793 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
800 symstrindex = shdr[i].sh_link;
804 * Ignore relocation tables for unallocated
807 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
812 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
820 if (ef->nprogtab == 0) {
821 link_elf_error(filename, "file has no contents");
826 /* Only allow one symbol table for now */
827 link_elf_error(filename,
828 "file must have exactly one symbol table");
832 if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
833 shdr[symstrindex].sh_type != SHT_STRTAB) {
834 link_elf_error(filename, "file has invalid symbol strings");
839 /* Allocate space for tracking the load chunks */
840 if (ef->nprogtab != 0)
841 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
842 M_LINKER, M_WAITOK | M_ZERO);
843 if (ef->nreltab != 0)
844 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
845 M_LINKER, M_WAITOK | M_ZERO);
846 if (ef->nrelatab != 0)
847 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
848 M_LINKER, M_WAITOK | M_ZERO);
850 if (symtabindex == -1) {
851 link_elf_error(filename, "lost symbol table index");
855 /* Allocate space for and load the symbol table */
856 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
857 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
858 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
859 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
860 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
869 /* Allocate space for and load the symbol strings */
870 ef->ddbstrcnt = shdr[symstrindex].sh_size;
871 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
872 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
873 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
874 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
883 /* Do we have a string table for the section names? */
885 if (hdr->e_shstrndx != 0 &&
886 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
887 shstrindex = hdr->e_shstrndx;
888 ef->shstrcnt = shdr[shstrindex].sh_size;
889 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
891 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
892 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
893 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
903 /* Size up code/data(progbits) and bss(nobits). */
905 for (i = 0; i < hdr->e_shnum; i++) {
906 if (shdr[i].sh_size == 0)
908 switch (shdr[i].sh_type) {
912 case SHT_X86_64_UNWIND:
916 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
918 alignmask = shdr[i].sh_addralign - 1;
919 mapsize += alignmask;
920 mapsize &= ~alignmask;
921 mapsize += shdr[i].sh_size;
927 * We know how much space we need for the text/data/bss/etc.
928 * This stuff needs to be in a single chunk so that profiling etc
929 * can get the bounds and gdb can associate offsets with modules
931 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize),
932 VM_PROT_ALL, 0, thread0.td_ucred);
933 if (ef->object == NULL) {
937 #if VM_NRESERVLEVEL > 0
938 vm_object_color(ef->object, 0);
942 * In order to satisfy amd64's architectural requirements on the
943 * location of code and data in the kernel's address space, request a
944 * mapping that is above the kernel.
946 * Protections will be restricted once relocations are applied.
951 mapbase = VM_MIN_KERNEL_ADDRESS;
953 error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
954 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
956 if (error != KERN_SUCCESS) {
957 vm_object_deallocate(ef->object);
964 error = vm_map_wire(kernel_map, mapbase,
965 mapbase + round_page(mapsize),
966 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
967 if (error != KERN_SUCCESS) {
972 /* Inform the kld system about the situation */
973 lf->address = ef->address = (caddr_t)mapbase;
977 * Now load code/data(progbits), zero bss(nobits), allocate space for
984 for (i = 0; i < hdr->e_shnum; i++) {
985 if (shdr[i].sh_size == 0)
987 switch (shdr[i].sh_type) {
991 case SHT_X86_64_UNWIND:
995 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
997 alignmask = shdr[i].sh_addralign - 1;
998 mapbase += alignmask;
999 mapbase &= ~alignmask;
1000 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
1001 ef->progtab[pb].name =
1002 ef->shstrtab + shdr[i].sh_name;
1003 if (!strcmp(ef->progtab[pb].name, ".ctors") ||
1004 shdr[i].sh_type == SHT_INIT_ARRAY) {
1005 if (lf->ctors_addr != 0) {
1007 "%s: multiple ctor sections in %s\n",
1008 __func__, filename);
1016 } else if (shdr[i].sh_type == SHT_PROGBITS)
1017 ef->progtab[pb].name = "<<PROGBITS>>";
1019 else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
1020 ef->progtab[pb].name = "<<UNWIND>>";
1023 ef->progtab[pb].name = "<<NOBITS>>";
1024 if (ef->progtab[pb].name != NULL &&
1025 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
1026 ef->progtab[pb].addr =
1027 dpcpu_alloc(shdr[i].sh_size);
1028 if (ef->progtab[pb].addr == NULL) {
1029 printf("%s: pcpu module space is out "
1030 "of space; cannot allocate %#jx "
1031 "for %s\n", __func__,
1032 (uintmax_t)shdr[i].sh_size,
1037 else if (ef->progtab[pb].name != NULL &&
1038 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
1039 ef->progtab[pb].addr =
1040 vnet_data_alloc(shdr[i].sh_size);
1041 if (ef->progtab[pb].addr == NULL) {
1042 printf("%s: vnet module space is out "
1043 "of space; cannot allocate %#jx "
1044 "for %s\n", __func__,
1045 (uintmax_t)shdr[i].sh_size,
1051 ef->progtab[pb].addr =
1052 (void *)(uintptr_t)mapbase;
1053 if (ef->progtab[pb].addr == NULL) {
1057 ef->progtab[pb].size = shdr[i].sh_size;
1058 ef->progtab[pb].flags = shdr[i].sh_flags;
1059 ef->progtab[pb].sec = i;
1060 if (shdr[i].sh_type == SHT_PROGBITS
1062 || shdr[i].sh_type == SHT_X86_64_UNWIND
1065 error = vn_rdwr(UIO_READ, nd->ni_vp,
1066 ef->progtab[pb].addr,
1067 shdr[i].sh_size, shdr[i].sh_offset,
1068 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
1069 NOCRED, &resid, td);
1076 /* Initialize the per-cpu or vnet area. */
1077 if (ef->progtab[pb].addr != (void *)mapbase &&
1078 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
1079 dpcpu_copy(ef->progtab[pb].addr,
1082 else if (ef->progtab[pb].addr !=
1084 !strcmp(ef->progtab[pb].name, VNET_SETNAME))
1085 vnet_data_copy(ef->progtab[pb].addr,
1089 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
1091 /* Update all symbol values with the offset. */
1092 for (j = 0; j < ef->ddbsymcnt; j++) {
1093 es = &ef->ddbsymtab[j];
1094 if (es->st_shndx != i)
1096 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
1098 mapbase += shdr[i].sh_size;
1102 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1104 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
1106 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
1107 ef->reltab[rl].sec = shdr[i].sh_info;
1108 error = vn_rdwr(UIO_READ, nd->ni_vp,
1109 (void *)ef->reltab[rl].rel,
1110 shdr[i].sh_size, shdr[i].sh_offset,
1111 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1122 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1124 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
1126 ef->relatab[ra].nrela =
1127 shdr[i].sh_size / sizeof(Elf_Rela);
1128 ef->relatab[ra].sec = shdr[i].sh_info;
1129 error = vn_rdwr(UIO_READ, nd->ni_vp,
1130 (void *)ef->relatab[ra].rela,
1131 shdr[i].sh_size, shdr[i].sh_offset,
1132 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1144 if (pb != ef->nprogtab) {
1145 link_elf_error(filename, "lost progbits");
1149 if (rl != ef->nreltab) {
1150 link_elf_error(filename, "lost reltab");
1154 if (ra != ef->nrelatab) {
1155 link_elf_error(filename, "lost relatab");
1159 if (mapbase != (vm_offset_t)ef->address + mapsize) {
1161 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
1162 filename != NULL ? filename : "<none>",
1163 (u_long)mapbase, ef->address, (u_long)mapsize,
1164 (u_long)(vm_offset_t)ef->address + mapsize);
1169 /* Local intra-module relocations */
1170 error = link_elf_reloc_local(lf, false);
1174 /* Pull in dependencies */
1175 VOP_UNLOCK(nd->ni_vp);
1176 error = linker_load_dependencies(lf);
1177 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
1181 /* External relocations */
1182 error = relocate_file(ef);
1186 /* Notify MD code that a module is being loaded. */
1187 error = elf_cpu_load_file(lf);
1191 #if defined(__i386__) || defined(__amd64__)
1193 error = link_elf_reloc_local(lf, true);
1198 link_elf_protect(ef);
1199 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
1203 VOP_UNLOCK(nd->ni_vp);
1204 vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1207 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1208 free(hdr, M_LINKER);
1214 link_elf_unload_file(linker_file_t file)
1216 elf_file_t ef = (elf_file_t) file;
1219 /* Notify MD code that a module is being unloaded. */
1220 elf_cpu_unload_file(file);
1223 for (i = 0; i < ef->nprogtab; i++) {
1224 if (ef->progtab[i].size == 0)
1226 if (ef->progtab[i].name == NULL)
1228 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1229 dpcpu_free(ef->progtab[i].addr,
1230 ef->progtab[i].size);
1232 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1233 vnet_data_free(ef->progtab[i].addr,
1234 ef->progtab[i].size);
1238 if (ef->preloaded) {
1239 free(ef->reltab, M_LINKER);
1240 free(ef->relatab, M_LINKER);
1241 free(ef->progtab, M_LINKER);
1242 free(ef->ctftab, M_LINKER);
1243 free(ef->ctfoff, M_LINKER);
1244 free(ef->typoff, M_LINKER);
1245 if (file->pathname != NULL)
1246 preload_delete_name(file->pathname);
1250 for (i = 0; i < ef->nreltab; i++)
1251 free(ef->reltab[i].rel, M_LINKER);
1252 for (i = 0; i < ef->nrelatab; i++)
1253 free(ef->relatab[i].rela, M_LINKER);
1254 free(ef->reltab, M_LINKER);
1255 free(ef->relatab, M_LINKER);
1256 free(ef->progtab, M_LINKER);
1258 if (ef->object != NULL)
1259 vm_map_remove(kernel_map, (vm_offset_t)ef->address,
1260 (vm_offset_t)ef->address + ptoa(ef->object->size));
1261 free(ef->e_shdr, M_LINKER);
1262 free(ef->ddbsymtab, M_LINKER);
1263 free(ef->ddbstrtab, M_LINKER);
1264 free(ef->shstrtab, M_LINKER);
1265 free(ef->ctftab, M_LINKER);
1266 free(ef->ctfoff, M_LINKER);
1267 free(ef->typoff, M_LINKER);
1271 symbol_name(elf_file_t ef, Elf_Size r_info)
1275 if (ELF_R_SYM(r_info)) {
1276 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1277 return ef->ddbstrtab + ref->st_name;
1283 findbase(elf_file_t ef, int sec)
1288 for (i = 0; i < ef->nprogtab; i++) {
1289 if (sec == ef->progtab[i].sec) {
1290 base = (Elf_Addr)ef->progtab[i].addr;
1298 relocate_file(elf_file_t ef)
1300 const Elf_Rel *rellim;
1302 const Elf_Rela *relalim;
1303 const Elf_Rela *rela;
1304 const char *symname;
1310 /* Perform relocations without addend if there are any: */
1311 for (i = 0; i < ef->nreltab; i++) {
1312 rel = ef->reltab[i].rel;
1314 link_elf_error(ef->lf.filename, "lost a reltab!");
1317 rellim = rel + ef->reltab[i].nrel;
1318 base = findbase(ef, ef->reltab[i].sec);
1320 link_elf_error(ef->lf.filename, "lost base for reltab");
1323 for ( ; rel < rellim; rel++) {
1324 symidx = ELF_R_SYM(rel->r_info);
1325 if (symidx >= ef->ddbsymcnt)
1327 sym = ef->ddbsymtab + symidx;
1328 /* Local relocs are already done */
1329 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1331 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1333 symname = symbol_name(ef, rel->r_info);
1334 printf("link_elf_obj: symbol %s undefined\n",
1341 /* Perform relocations with addend if there are any: */
1342 for (i = 0; i < ef->nrelatab; i++) {
1343 rela = ef->relatab[i].rela;
1345 link_elf_error(ef->lf.filename, "lost a relatab!");
1348 relalim = rela + ef->relatab[i].nrela;
1349 base = findbase(ef, ef->relatab[i].sec);
1351 link_elf_error(ef->lf.filename,
1352 "lost base for relatab");
1355 for ( ; rela < relalim; rela++) {
1356 symidx = ELF_R_SYM(rela->r_info);
1357 if (symidx >= ef->ddbsymcnt)
1359 sym = ef->ddbsymtab + symidx;
1360 /* Local relocs are already done */
1361 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1363 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1365 symname = symbol_name(ef, rela->r_info);
1366 printf("link_elf_obj: symbol %s undefined\n",
1374 * Only clean SHN_FBSD_CACHED for successful return. If we
1375 * modified symbol table for the object but found an
1376 * unresolved symbol, there is no reason to roll back.
1378 elf_obj_cleanup_globals_cache(ef);
1384 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1386 elf_file_t ef = (elf_file_t) lf;
1387 const Elf_Sym *symp;
1391 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1392 strp = ef->ddbstrtab + symp->st_name;
1393 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1394 *sym = (c_linker_sym_t) symp;
1402 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1403 linker_symval_t *symval)
1409 ef = (elf_file_t) lf;
1410 es = (const Elf_Sym*) sym;
1411 val = (caddr_t)es->st_value;
1412 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1413 symval->name = ef->ddbstrtab + es->st_name;
1414 val = (caddr_t)es->st_value;
1415 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1416 val = ((caddr_t (*)(void))val)();
1417 symval->value = val;
1418 symval->size = es->st_size;
1425 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1426 c_linker_sym_t *sym, long *diffp)
1428 elf_file_t ef = (elf_file_t) lf;
1429 u_long off = (uintptr_t) (void *) value;
1433 const Elf_Sym *best = NULL;
1436 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1437 if (es->st_name == 0)
1439 st_value = es->st_value;
1440 if (off >= st_value) {
1441 if (off - st_value < diff) {
1442 diff = off - st_value;
1446 } else if (off - st_value == diff) {
1455 *sym = (c_linker_sym_t) best;
1461 * Look up a linker set on an ELF system.
1464 link_elf_lookup_set(linker_file_t lf, const char *name,
1465 void ***startp, void ***stopp, int *countp)
1467 elf_file_t ef = (elf_file_t)lf;
1468 void **start, **stop;
1471 /* Relative to section number */
1472 for (i = 0; i < ef->nprogtab; i++) {
1473 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1474 strcmp(ef->progtab[i].name + 4, name) == 0) {
1475 start = (void **)ef->progtab[i].addr;
1476 stop = (void **)((char *)ef->progtab[i].addr +
1477 ef->progtab[i].size);
1478 count = stop - start;
1492 link_elf_each_function_name(linker_file_t file,
1493 int (*callback)(const char *, void *), void *opaque)
1495 elf_file_t ef = (elf_file_t)file;
1496 const Elf_Sym *symp;
1499 /* Exhaustive search */
1500 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1501 if (symp->st_value != 0 &&
1502 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1503 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1504 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1513 link_elf_each_function_nameval(linker_file_t file,
1514 linker_function_nameval_callback_t callback, void *opaque)
1516 linker_symval_t symval;
1517 elf_file_t ef = (elf_file_t)file;
1518 const Elf_Sym* symp;
1521 /* Exhaustive search */
1522 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1523 if (symp->st_value != 0 &&
1524 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1525 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1526 error = link_elf_symbol_values(file,
1527 (c_linker_sym_t)symp, &symval);
1530 error = callback(file, i, &symval, opaque);
1539 elf_obj_cleanup_globals_cache(elf_file_t ef)
1544 for (i = 0; i < ef->ddbsymcnt; i++) {
1545 sym = ef->ddbsymtab + i;
1546 if (sym->st_shndx == SHN_FBSD_CACHED) {
1547 sym->st_shndx = SHN_UNDEF;
1554 * Symbol lookup function that can be used when the symbol index is known (ie
1555 * in relocations). It uses the symbol index instead of doing a fully fledged
1556 * hash table based lookup when such is valid. For example for local symbols.
1557 * This is not only more efficient, it's also more correct. It's not always
1558 * the case that the symbol can be found through the hash table.
1561 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1563 elf_file_t ef = (elf_file_t)lf;
1568 /* Don't even try to lookup the symbol if the index is bogus. */
1569 if (symidx >= ef->ddbsymcnt) {
1574 sym = ef->ddbsymtab + symidx;
1576 /* Quick answer if there is a definition included. */
1577 if (sym->st_shndx != SHN_UNDEF) {
1578 res1 = (Elf_Addr)sym->st_value;
1579 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1580 res1 = ((Elf_Addr (*)(void))res1)();
1585 /* If we get here, then it is undefined and needs a lookup. */
1586 switch (ELF_ST_BIND(sym->st_info)) {
1588 /* Local, but undefined? huh? */
1594 /* Relative to Data or Function name */
1595 symbol = ef->ddbstrtab + sym->st_name;
1597 /* Force a lookup failure if the symbol name is bogus. */
1602 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1605 * Cache global lookups during module relocation. The failure
1606 * case is particularly expensive for callers, who must scan
1607 * through the entire globals table doing strcmp(). Cache to
1608 * avoid doing such work repeatedly.
1610 * After relocation is complete, undefined globals will be
1611 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1615 sym->st_shndx = SHN_FBSD_CACHED;
1616 sym->st_value = res1;
1619 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1632 link_elf_fix_link_set(elf_file_t ef)
1634 static const char startn[] = "__start_";
1635 static const char stopn[] = "__stop_";
1637 const char *sym_name, *linkset_name;
1638 Elf_Addr startp, stopp;
1643 for (symidx = 1 /* zero entry is special */;
1644 symidx < ef->ddbsymcnt; symidx++) {
1645 sym = ef->ddbsymtab + symidx;
1646 if (sym->st_shndx != SHN_UNDEF)
1649 sym_name = ef->ddbstrtab + sym->st_name;
1650 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1652 linkset_name = sym_name + sizeof(startn) - 1;
1654 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1656 linkset_name = sym_name + sizeof(stopn) - 1;
1661 for (i = 0; i < ef->nprogtab; i++) {
1662 if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1663 startp = (Elf_Addr)ef->progtab[i].addr;
1664 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1668 if (i == ef->nprogtab)
1671 sym->st_value = start ? startp : stopp;
1677 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1679 elf_file_t ef = (elf_file_t)lf;
1680 const Elf_Rel *rellim;
1682 const Elf_Rela *relalim;
1683 const Elf_Rela *rela;
1689 link_elf_fix_link_set(ef);
1691 /* Perform relocations without addend if there are any: */
1692 for (i = 0; i < ef->nreltab; i++) {
1693 rel = ef->reltab[i].rel;
1695 link_elf_error(ef->lf.filename, "lost a reltab");
1698 rellim = rel + ef->reltab[i].nrel;
1699 base = findbase(ef, ef->reltab[i].sec);
1701 link_elf_error(ef->lf.filename, "lost base for reltab");
1704 for ( ; rel < rellim; rel++) {
1705 symidx = ELF_R_SYM(rel->r_info);
1706 if (symidx >= ef->ddbsymcnt)
1708 sym = ef->ddbsymtab + symidx;
1709 /* Only do local relocs */
1710 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1712 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1713 elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
1715 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1716 elf_obj_lookup) != 0)
1721 /* Perform relocations with addend if there are any: */
1722 for (i = 0; i < ef->nrelatab; i++) {
1723 rela = ef->relatab[i].rela;
1725 link_elf_error(ef->lf.filename, "lost a relatab!");
1728 relalim = rela + ef->relatab[i].nrela;
1729 base = findbase(ef, ef->relatab[i].sec);
1731 link_elf_error(ef->lf.filename, "lost base for reltab");
1734 for ( ; rela < relalim; rela++) {
1735 symidx = ELF_R_SYM(rela->r_info);
1736 if (symidx >= ef->ddbsymcnt)
1738 sym = ef->ddbsymtab + symidx;
1739 /* Only do local relocs */
1740 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1742 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1743 elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
1745 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1746 elf_obj_lookup) != 0)
1754 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1756 elf_file_t ef = (elf_file_t)lf;
1758 *symtab = ef->ddbsymtab;
1760 if (*symtab == NULL)
1763 return (ef->ddbsymcnt);
1767 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1769 elf_file_t ef = (elf_file_t)lf;
1771 *strtab = ef->ddbstrtab;
1773 if (*strtab == NULL)
1776 return (ef->ddbstrcnt);