2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1998-2000 Doug Rabson
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
40 #include <sys/kernel.h>
42 #include <sys/malloc.h>
46 #include <sys/mutex.h>
47 #include <sys/mount.h>
50 #include <sys/namei.h>
51 #include <sys/fcntl.h>
52 #include <sys/vnode.h>
53 #include <sys/linker.h>
55 #include <machine/elf.h>
59 #include <security/mac/mac_framework.h>
62 #include <vm/vm_param.h>
64 #include <vm/vm_object.h>
65 #include <vm/vm_kern.h>
66 #include <vm/vm_extern.h>
69 #include <vm/vm_map.h>
71 #include <sys/link_elf.h>
77 #include "linker_if.h"
81 typedef struct elf_file {
82 struct linker_file lf; /* Common fields */
83 int preloaded; /* Was file pre-loaded */
84 caddr_t address; /* Relocation address */
86 vm_object_t object; /* VM object to hold file pages */
88 Elf_Dyn *dynamic; /* Symbol table etc. */
89 Elf_Hashelt nbuckets; /* DT_HASH info */
91 const Elf_Hashelt *buckets;
92 const Elf_Hashelt *chains;
94 caddr_t strtab; /* DT_STRTAB */
95 int strsz; /* DT_STRSZ */
96 const Elf_Sym *symtab; /* DT_SYMTAB */
97 Elf_Addr *got; /* DT_PLTGOT */
98 const Elf_Rel *pltrel; /* DT_JMPREL */
99 int pltrelsize; /* DT_PLTRELSZ */
100 const Elf_Rela *pltrela; /* DT_JMPREL */
101 int pltrelasize; /* DT_PLTRELSZ */
102 const Elf_Rel *rel; /* DT_REL */
103 int relsize; /* DT_RELSZ */
104 const Elf_Rela *rela; /* DT_RELA */
105 int relasize; /* DT_RELASZ */
107 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
108 long ddbsymcnt; /* Number of symbols */
109 caddr_t ddbstrtab; /* String table */
110 long ddbstrcnt; /* number of bytes in string table */
111 caddr_t symbase; /* malloc'ed symbold base */
112 caddr_t strbase; /* malloc'ed string base */
113 caddr_t ctftab; /* CTF table */
114 long ctfcnt; /* number of bytes in CTF table */
115 caddr_t ctfoff; /* CTF offset table */
116 caddr_t typoff; /* Type offset table */
117 long typlen; /* Number of type entries. */
118 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
119 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
120 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
122 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
123 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
124 Elf_Addr vnet_base; /* Relocated vnet set address. */
127 struct link_map gdb; /* hooks for gdb */
135 TAILQ_ENTRY(elf_set) es_link;
138 TAILQ_HEAD(elf_set_head, elf_set);
140 #include <kern/kern_ctf.c>
142 static int link_elf_link_common_finish(linker_file_t);
143 static int link_elf_link_preload(linker_class_t cls,
144 const char *, linker_file_t *);
145 static int link_elf_link_preload_finish(linker_file_t);
146 static int link_elf_load_file(linker_class_t, const char *,
148 static int link_elf_lookup_symbol(linker_file_t, const char *,
150 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
152 static int link_elf_search_symbol(linker_file_t, caddr_t,
153 c_linker_sym_t *, long *);
155 static void link_elf_unload_file(linker_file_t);
156 static void link_elf_unload_preload(linker_file_t);
157 static int link_elf_lookup_set(linker_file_t, const char *,
158 void ***, void ***, int *);
159 static int link_elf_each_function_name(linker_file_t,
160 int (*)(const char *, void *), void *);
161 static int link_elf_each_function_nameval(linker_file_t,
162 linker_function_nameval_callback_t, void *);
163 static void link_elf_reloc_local(linker_file_t);
164 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
165 static long link_elf_strtab_get(linker_file_t, caddr_t *);
166 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
168 static kobj_method_t link_elf_methods[] = {
169 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
170 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
171 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
172 KOBJMETHOD(linker_unload, link_elf_unload_file),
173 KOBJMETHOD(linker_load_file, link_elf_load_file),
174 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
175 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
176 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
177 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
178 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
179 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
180 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
181 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
185 static struct linker_class link_elf_class = {
186 #if ELF_TARG_CLASS == ELFCLASS32
191 link_elf_methods, sizeof(struct elf_file)
194 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase,
195 const void *data, int type, elf_lookup_fn lookup);
197 static int parse_dynamic(elf_file_t);
198 static int relocate_file(elf_file_t);
199 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup,
200 elf_reloc_fn reloc, bool ifuncs);
201 static int link_elf_preload_parse_symbols(elf_file_t);
203 static struct elf_set_head set_pcpu_list;
205 static struct elf_set_head set_vnet_list;
209 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
211 struct elf_set *set, *iter;
213 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
214 set->es_start = start;
218 TAILQ_FOREACH(iter, list, es_link) {
220 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
221 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
222 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
223 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
224 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
226 if (iter->es_start > set->es_start) {
227 TAILQ_INSERT_BEFORE(iter, set, es_link);
233 TAILQ_INSERT_TAIL(list, set, es_link);
237 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
241 TAILQ_FOREACH(set, list, es_link) {
242 if (addr < set->es_start)
244 if (addr < set->es_stop) {
245 *start = set->es_start;
246 *base = set->es_base;
255 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
259 TAILQ_FOREACH(set, list, es_link) {
260 if (start < set->es_start)
262 if (start == set->es_start) {
263 TAILQ_REMOVE(list, set, es_link);
268 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
273 static void r_debug_state(struct r_debug *, struct link_map *);
276 * A list of loaded modules for GDB to use for loading symbols.
278 struct r_debug r_debug;
280 #define GDB_STATE(s) do { \
281 r_debug.r_state = s; r_debug_state(NULL, NULL); \
285 * Function for the debugger to set a breakpoint on to gain control.
288 r_debug_state(struct r_debug *dummy_one __unused,
289 struct link_map *dummy_two __unused)
294 link_elf_add_gdb(struct link_map *l)
296 struct link_map *prev;
300 if (r_debug.r_map == NULL) {
305 /* Append to list. */
306 for (prev = r_debug.r_map;
307 prev->l_next != NULL;
316 link_elf_delete_gdb(struct link_map *l)
318 if (l->l_prev == NULL) {
320 if ((r_debug.r_map = l->l_next) != NULL)
321 l->l_next->l_prev = NULL;
323 /* Remove any but first. */
324 if ((l->l_prev->l_next = l->l_next) != NULL)
325 l->l_next->l_prev = l->l_prev;
331 * The kernel symbol table starts here.
333 extern struct _dynamic _DYNAMIC;
336 link_elf_error(const char *filename, const char *s)
338 if (filename == NULL)
339 printf("kldload: %s\n", s);
341 printf("kldload: %s: %s\n", filename, s);
345 link_elf_invoke_ctors(caddr_t addr, size_t size)
350 if (addr == NULL || size == 0)
352 cnt = size / sizeof(*ctor);
354 for (i = 0; i < cnt; i++) {
361 * Actions performed after linking/loading both the preloaded kernel and any
362 * modules; whether preloaded or dynamicly loaded.
365 link_elf_link_common_finish(linker_file_t lf)
368 elf_file_t ef = (elf_file_t)lf;
373 /* Notify MD code that a module is being loaded. */
374 error = elf_cpu_load_file(lf);
380 ef->gdb.l_addr = lf->address;
381 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
382 strcpy(newfilename, lf->filename);
383 ef->gdb.l_name = newfilename;
384 ef->gdb.l_ld = ef->dynamic;
385 link_elf_add_gdb(&ef->gdb);
386 GDB_STATE(RT_CONSISTENT);
390 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
394 extern vm_offset_t __startkernel, __endkernel;
397 link_elf_init(void* arg)
400 Elf_Addr *ctors_addrp;
401 Elf_Size *ctors_sizep;
402 caddr_t modptr, baseptr, sizeptr;
406 linker_add_class(&link_elf_class);
408 dp = (Elf_Dyn *)&_DYNAMIC;
410 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
412 modptr = preload_search_by_type("elf kernel");
413 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
416 linker_kernel_file = linker_make_file(modname, &link_elf_class);
417 if (linker_kernel_file == NULL)
418 panic("%s: Can't create linker structures for kernel",
421 ef = (elf_file_t) linker_kernel_file;
424 ef->address = (caddr_t) (__startkernel - KERNBASE);
428 #ifdef SPARSE_MAPPING
436 linker_kernel_file->address = (caddr_t)__startkernel;
437 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
439 linker_kernel_file->address += KERNBASE;
440 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
443 if (modptr != NULL) {
445 baseptr = preload_search_info(modptr, MODINFO_ADDR);
447 linker_kernel_file->address = *(caddr_t *)baseptr;
448 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
450 linker_kernel_file->size = *(size_t *)sizeptr;
451 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
452 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
453 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
454 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
455 if (ctors_addrp != NULL && ctors_sizep != NULL) {
456 linker_kernel_file->ctors_addr = ef->address +
458 linker_kernel_file->ctors_size = *ctors_sizep;
461 (void)link_elf_preload_parse_symbols(ef);
464 r_debug.r_map = NULL;
465 r_debug.r_brk = r_debug_state;
466 r_debug.r_state = RT_CONSISTENT;
469 (void)link_elf_link_common_finish(linker_kernel_file);
470 linker_kernel_file->flags |= LINKER_FILE_LINKED;
471 TAILQ_INIT(&set_pcpu_list);
473 TAILQ_INIT(&set_vnet_list);
477 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL);
480 link_elf_preload_parse_symbols(elf_file_t ef)
483 caddr_t ssym, esym, base;
489 if (ef->modptr == NULL)
491 pointer = preload_search_info(ef->modptr,
492 MODINFO_METADATA | MODINFOMD_SSYM);
495 ssym = *(caddr_t *)pointer;
496 pointer = preload_search_info(ef->modptr,
497 MODINFO_METADATA | MODINFOMD_ESYM);
500 esym = *(caddr_t *)pointer;
504 symcnt = *(long *)base;
505 base += sizeof(long);
506 symtab = (Elf_Sym *)base;
507 base += roundup(symcnt, sizeof(long));
509 if (base > esym || base < ssym) {
510 printf("Symbols are corrupt!\n");
514 strcnt = *(long *)base;
515 base += sizeof(long);
517 base += roundup(strcnt, sizeof(long));
519 if (base > esym || base < ssym) {
520 printf("Symbols are corrupt!\n");
524 ef->ddbsymtab = symtab;
525 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
526 ef->ddbstrtab = strtab;
527 ef->ddbstrcnt = strcnt;
533 parse_dynamic(elf_file_t ef)
536 int plttype = DT_REL;
538 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
542 /* From src/libexec/rtld-elf/rtld.c */
543 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
544 (ef->address + dp->d_un.d_ptr);
545 ef->nbuckets = hashtab[0];
546 ef->nchains = hashtab[1];
547 ef->buckets = hashtab + 2;
548 ef->chains = ef->buckets + ef->nbuckets;
552 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
555 ef->strsz = dp->d_un.d_val;
558 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
561 if (dp->d_un.d_val != sizeof(Elf_Sym))
565 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
568 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
571 ef->relsize = dp->d_un.d_val;
574 if (dp->d_un.d_val != sizeof(Elf_Rel))
578 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
581 ef->pltrelsize = dp->d_un.d_val;
584 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
587 ef->relasize = dp->d_un.d_val;
590 if (dp->d_un.d_val != sizeof(Elf_Rela))
594 plttype = dp->d_un.d_val;
595 if (plttype != DT_REL && plttype != DT_RELA)
600 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
606 if (plttype == DT_RELA) {
607 ef->pltrela = (const Elf_Rela *)ef->pltrel;
609 ef->pltrelasize = ef->pltrelsize;
613 ef->ddbsymtab = ef->symtab;
614 ef->ddbsymcnt = ef->nchains;
615 ef->ddbstrtab = ef->strtab;
616 ef->ddbstrcnt = ef->strsz;
622 parse_dpcpu(elf_file_t ef)
628 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
629 (void ***)&ef->pcpu_stop, NULL);
630 /* Error just means there is no pcpu set to relocate. */
633 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start;
638 * Allocate space in the primary pcpu area. Copy in our
639 * initialization from the data section and then initialize
640 * all per-cpu storage from that.
642 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size);
643 if (ef->pcpu_base == 0) {
644 printf("%s: pcpu module space is out of space; "
645 "cannot allocate %d for %s\n",
646 __func__, size, ef->lf.pathname);
649 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size);
650 dpcpu_copy((void *)ef->pcpu_base, size);
651 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
659 parse_vnet(elf_file_t ef)
665 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
666 (void ***)&ef->vnet_stop, NULL);
667 /* Error just means there is no vnet data set to relocate. */
670 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start;
675 * Allocate space in the primary vnet area. Copy in our
676 * initialization from the data section and then initialize
677 * all per-vnet storage from that.
679 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size);
680 if (ef->vnet_base == 0) {
681 printf("%s: vnet module space is out of space; "
682 "cannot allocate %d for %s\n",
683 __func__, size, ef->lf.pathname);
686 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size);
687 vnet_data_copy((void *)ef->vnet_base, size);
688 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
697 * Locate the ARM exception/unwind table info for DDB and stack(9) use by
698 * searching for the section header that describes it. There may be no unwind
699 * info, for example in a module containing only data.
702 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr)
706 for (i = 0; i < nhdr; i++) {
707 if (shdr[i].sh_type == SHT_ARM_EXIDX) {
708 lf->exidx_addr = shdr[i].sh_addr + lf->address;
709 lf->exidx_size = shdr[i].sh_size;
716 * Locate the section headers metadata in a preloaded module, then use it to
717 * locate the exception/unwind table in the module. The size of the metadata
718 * block is stored in a uint32 word immediately before the data itself, and a
719 * comment in preload_search_info() says it is safe to rely on that.
722 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr)
728 modinfo = (uint32_t *)preload_search_info(modptr,
729 MODINFO_METADATA | MODINFOMD_SHDR);
730 if (modinfo != NULL) {
731 shdr = (Elf_Shdr *)modinfo;
732 nhdr = modinfo[-1] / sizeof(Elf_Shdr);
733 link_elf_locate_exidx(lf, shdr, nhdr);
740 link_elf_link_preload(linker_class_t cls,
741 const char* filename, linker_file_t *result)
743 Elf_Addr *ctors_addrp;
744 Elf_Size *ctors_sizep;
745 caddr_t modptr, baseptr, sizeptr, dynptr;
752 /* Look to see if we have the file preloaded */
753 modptr = preload_search_by_name(filename);
757 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
758 baseptr = preload_search_info(modptr, MODINFO_ADDR);
759 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
760 dynptr = preload_search_info(modptr,
761 MODINFO_METADATA | MODINFOMD_DYNAMIC);
763 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
764 strcmp(type, "elf module") != 0))
766 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
769 lf = linker_make_file(filename, &link_elf_class);
773 ef = (elf_file_t) lf;
776 ef->address = *(caddr_t *)baseptr;
777 #ifdef SPARSE_MAPPING
780 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
781 ef->dynamic = (Elf_Dyn *)dp;
782 lf->address = ef->address;
783 lf->size = *(size_t *)sizeptr;
785 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
786 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
787 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
788 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
789 if (ctors_addrp != NULL && ctors_sizep != NULL) {
790 lf->ctors_addr = ef->address + *ctors_addrp;
791 lf->ctors_size = *ctors_sizep;
795 link_elf_locate_exidx_preload(lf, modptr);
798 error = parse_dynamic(ef);
800 error = parse_dpcpu(ef);
803 error = parse_vnet(ef);
806 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
809 link_elf_reloc_local(lf);
815 link_elf_link_preload_finish(linker_file_t lf)
820 ef = (elf_file_t) lf;
821 error = relocate_file(ef);
824 (void)link_elf_preload_parse_symbols(ef);
826 return (link_elf_link_common_finish(lf));
830 link_elf_load_file(linker_class_t cls, const char* filename,
831 linker_file_t* result)
834 struct thread* td = curthread; /* XXX */
836 caddr_t firstpage, segbase;
840 Elf_Phdr *segs[MAXSEGS];
846 Elf_Addr base_vlimit;
864 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
866 error = vn_open(&nd, &flags, 0, NULL);
869 NDFREE(&nd, NDF_ONLY_PNBUF);
870 if (nd.ni_vp->v_type != VREG) {
876 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
884 * Read the elf header from the file.
886 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
887 hdr = (Elf_Ehdr *)firstpage;
888 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
889 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
891 nbytes = PAGE_SIZE - resid;
900 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
901 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
902 link_elf_error(filename, "Unsupported file layout");
906 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
907 hdr->e_version != EV_CURRENT) {
908 link_elf_error(filename, "Unsupported file version");
912 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
916 if (hdr->e_machine != ELF_TARG_MACH) {
917 link_elf_error(filename, "Unsupported machine");
923 * We rely on the program header being in the first page.
924 * This is not strictly required by the ABI specification, but
925 * it seems to always true in practice. And, it simplifies
926 * things considerably.
928 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
929 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
930 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
931 link_elf_error(filename, "Unreadable program headers");
934 * Scan the program header entries, and save key information.
936 * We rely on there being exactly two load segments, text and data,
939 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
940 phlimit = phdr + hdr->e_phnum;
943 while (phdr < phlimit) {
944 switch (phdr->p_type) {
946 if (nsegs == MAXSEGS) {
947 link_elf_error(filename, "Too many sections");
952 * XXX: We just trust they come in right order ??
970 link_elf_error(filename, "Object is not dynamically-linked");
975 link_elf_error(filename, "No sections");
981 * Allocate the entire address space of the object, to stake
982 * out our contiguous region, and to establish the base
983 * address for relocation.
985 base_vaddr = trunc_page(segs[0]->p_vaddr);
986 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
987 segs[nsegs - 1]->p_memsz);
988 mapsize = base_vlimit - base_vaddr;
990 lf = linker_make_file(filename, &link_elf_class);
996 ef = (elf_file_t) lf;
997 #ifdef SPARSE_MAPPING
998 ef->object = vm_object_allocate(OBJT_PHYS, atop(mapsize));
999 if (ef->object == NULL) {
1004 mapbase = (caddr_t)KERNBASE;
1006 mapbase = (caddr_t)vm_map_min(kernel_map);
1009 * Mapping protections are downgraded after relocation processing.
1011 error = vm_map_find(kernel_map, ef->object, 0,
1012 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE,
1013 VM_PROT_ALL, VM_PROT_ALL, 0);
1015 vm_object_deallocate(ef->object);
1020 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK);
1022 ef->address = mapbase;
1025 * Read the text and data sections and zero the bss.
1027 for (i = 0; i < nsegs; i++) {
1028 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1030 #ifdef SPARSE_MAPPING
1032 * Consecutive segments may have different mapping permissions,
1033 * so be strict and verify that their mappings do not overlap.
1035 if (((vm_offset_t)segbase & PAGE_MASK) != 0) {
1040 error = vm_map_wire(kernel_map,
1041 (vm_offset_t)segbase,
1042 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1043 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
1044 if (error != KERN_SUCCESS) {
1050 error = vn_rdwr(UIO_READ, nd.ni_vp,
1051 segbase, segs[i]->p_filesz, segs[i]->p_offset,
1052 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1056 bzero(segbase + segs[i]->p_filesz,
1057 segs[i]->p_memsz - segs[i]->p_filesz);
1061 /* Update profiling information with the new text segment. */
1063 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
1068 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
1070 lf->address = ef->address;
1073 error = parse_dynamic(ef);
1076 error = parse_dpcpu(ef);
1080 error = parse_vnet(ef);
1084 link_elf_reloc_local(lf);
1086 VOP_UNLOCK(nd.ni_vp, 0);
1087 error = linker_load_dependencies(lf);
1088 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1091 error = relocate_file(ef);
1095 #ifdef SPARSE_MAPPING
1097 * Downgrade permissions on text segment mappings now that relocation
1098 * processing is complete. Restrict permissions on read-only segments.
1100 for (i = 0; i < nsegs; i++) {
1103 if (segs[i]->p_type != PT_LOAD)
1106 prot = VM_PROT_READ;
1107 if ((segs[i]->p_flags & PF_W) != 0)
1108 prot |= VM_PROT_WRITE;
1109 if ((segs[i]->p_flags & PF_X) != 0)
1110 prot |= VM_PROT_EXECUTE;
1111 segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
1112 error = vm_map_protect(kernel_map,
1113 (vm_offset_t)segbase,
1114 (vm_offset_t)segbase + round_page(segs[i]->p_memsz),
1116 if (error != KERN_SUCCESS) {
1124 * Try and load the symbol table if it's present. (you can
1127 nbytes = hdr->e_shnum * hdr->e_shentsize;
1128 if (nbytes == 0 || hdr->e_shoff == 0)
1130 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1131 error = vn_rdwr(UIO_READ, nd.ni_vp,
1132 (caddr_t)shdr, nbytes, hdr->e_shoff,
1133 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1138 /* Read section string table */
1139 shstrindex = hdr->e_shstrndx;
1140 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1141 shdr[shstrindex].sh_size != 0) {
1142 nbytes = shdr[shstrindex].sh_size;
1143 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1144 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1145 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1146 td->td_ucred, NOCRED, &resid, td);
1153 for (i = 0; i < hdr->e_shnum; i++) {
1154 if (shdr[i].sh_type == SHT_SYMTAB) {
1156 symstrindex = shdr[i].sh_link;
1157 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1158 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1159 /* Record relocated address and size of .ctors. */
1160 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1161 lf->ctors_size = shdr[i].sh_size;
1164 if (symtabindex < 0 || symstrindex < 0)
1167 symcnt = shdr[symtabindex].sh_size;
1168 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1169 strcnt = shdr[symstrindex].sh_size;
1170 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1172 error = vn_rdwr(UIO_READ, nd.ni_vp,
1173 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1174 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1178 error = vn_rdwr(UIO_READ, nd.ni_vp,
1179 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1180 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1185 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1186 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1187 ef->ddbstrcnt = strcnt;
1188 ef->ddbstrtab = ef->strbase;
1193 link_elf_locate_exidx(lf, shdr, hdr->e_shnum);
1196 error = link_elf_link_common_finish(lf);
1203 VOP_UNLOCK(nd.ni_vp, 0);
1204 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1205 if (error != 0 && lf != NULL)
1206 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1207 free(shdr, M_LINKER);
1208 free(firstpage, M_LINKER);
1209 free(shstrs, M_LINKER);
1215 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1219 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class,
1220 ("elf_relocaddr: unexpected linker file %p", lf));
1222 ef = (elf_file_t)lf;
1223 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1224 return ((x - ef->pcpu_start) + ef->pcpu_base);
1226 if (x >= ef->vnet_start && x < ef->vnet_stop)
1227 return ((x - ef->vnet_start) + ef->vnet_base);
1234 link_elf_unload_file(linker_file_t file)
1236 elf_file_t ef = (elf_file_t) file;
1238 if (ef->pcpu_base != 0) {
1239 dpcpu_free((void *)ef->pcpu_base,
1240 ef->pcpu_stop - ef->pcpu_start);
1241 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1244 if (ef->vnet_base != 0) {
1245 vnet_data_free((void *)ef->vnet_base,
1246 ef->vnet_stop - ef->vnet_start);
1247 elf_set_delete(&set_vnet_list, ef->vnet_start);
1251 if (ef->gdb.l_ld != NULL) {
1252 GDB_STATE(RT_DELETE);
1253 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1254 link_elf_delete_gdb(&ef->gdb);
1255 GDB_STATE(RT_CONSISTENT);
1259 /* Notify MD code that a module is being unloaded. */
1260 elf_cpu_unload_file(file);
1262 if (ef->preloaded) {
1263 link_elf_unload_preload(file);
1267 #ifdef SPARSE_MAPPING
1268 if (ef->object != NULL) {
1269 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1270 (vm_offset_t) ef->address
1271 + (ef->object->size << PAGE_SHIFT));
1274 free(ef->address, M_LINKER);
1276 free(ef->symbase, M_LINKER);
1277 free(ef->strbase, M_LINKER);
1278 free(ef->ctftab, M_LINKER);
1279 free(ef->ctfoff, M_LINKER);
1280 free(ef->typoff, M_LINKER);
1284 link_elf_unload_preload(linker_file_t file)
1286 if (file->pathname != NULL)
1287 preload_delete_name(file->pathname);
1291 symbol_name(elf_file_t ef, Elf_Size r_info)
1295 if (ELF_R_SYM(r_info)) {
1296 ref = ef->symtab + ELF_R_SYM(r_info);
1297 return (ef->strtab + ref->st_name);
1303 symbol_type(elf_file_t ef, Elf_Size r_info)
1307 if (ELF_R_SYM(r_info)) {
1308 ref = ef->symtab + ELF_R_SYM(r_info);
1309 return (ELF_ST_TYPE(ref->st_info));
1311 return (STT_NOTYPE);
1315 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc,
1319 const Elf_Rela *rela;
1320 const char *symname;
1322 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \
1323 for ((iter) = (tbl); (iter) != NULL && \
1324 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \
1325 if ((symbol_type(ef, (iter)->r_info) == \
1327 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \
1329 if (reloc(&ef->lf, (Elf_Addr)ef->address, \
1330 (iter), (type), lookup)) { \
1331 symname = symbol_name(ef, (iter)->r_info); \
1332 printf("link_elf: symbol %s undefined\n", \
1339 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL);
1340 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA);
1341 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL);
1342 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA);
1350 relocate_file(elf_file_t ef)
1354 error = relocate_file1(ef, elf_lookup, elf_reloc, false);
1356 error = relocate_file1(ef, elf_lookup, elf_reloc, true);
1361 * Hash function for symbol table lookup. Don't even think about changing
1362 * this. It is specified by the System V ABI.
1364 static unsigned long
1365 elf_hash(const char *name)
1367 const unsigned char *p = (const unsigned char *) name;
1368 unsigned long h = 0;
1371 while (*p != '\0') {
1372 h = (h << 4) + *p++;
1373 if ((g = h & 0xf0000000) != 0)
1381 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1383 elf_file_t ef = (elf_file_t) lf;
1384 unsigned long symnum;
1385 const Elf_Sym* symp;
1390 /* If we don't have a hash, bail. */
1391 if (ef->buckets == NULL || ef->nbuckets == 0) {
1392 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1396 /* First, search hashed global symbols */
1397 hash = elf_hash(name);
1398 symnum = ef->buckets[hash % ef->nbuckets];
1400 while (symnum != STN_UNDEF) {
1401 if (symnum >= ef->nchains) {
1402 printf("%s: corrupt symbol table\n", __func__);
1406 symp = ef->symtab + symnum;
1407 if (symp->st_name == 0) {
1408 printf("%s: corrupt symbol table\n", __func__);
1412 strp = ef->strtab + symp->st_name;
1414 if (strcmp(name, strp) == 0) {
1415 if (symp->st_shndx != SHN_UNDEF ||
1416 (symp->st_value != 0 &&
1417 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1418 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1419 *sym = (c_linker_sym_t) symp;
1425 symnum = ef->chains[symnum];
1428 /* If we have not found it, look at the full table (if loaded) */
1429 if (ef->symtab == ef->ddbsymtab)
1432 /* Exhaustive search */
1433 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1434 strp = ef->ddbstrtab + symp->st_name;
1435 if (strcmp(name, strp) == 0) {
1436 if (symp->st_shndx != SHN_UNDEF ||
1437 (symp->st_value != 0 &&
1438 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1439 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
1440 *sym = (c_linker_sym_t) symp;
1451 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1452 linker_symval_t *symval)
1458 ef = (elf_file_t)lf;
1459 es = (const Elf_Sym *)sym;
1460 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1461 symval->name = ef->strtab + es->st_name;
1462 val = (caddr_t)ef->address + es->st_value;
1463 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1464 val = ((caddr_t (*)(void))val)();
1465 symval->value = val;
1466 symval->size = es->st_size;
1469 if (ef->symtab == ef->ddbsymtab)
1471 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1472 symval->name = ef->ddbstrtab + es->st_name;
1473 val = (caddr_t)ef->address + es->st_value;
1474 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1475 val = ((caddr_t (*)(void))val)();
1476 symval->value = val;
1477 symval->size = es->st_size;
1484 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1485 c_linker_sym_t *sym, long *diffp)
1487 elf_file_t ef = (elf_file_t) lf;
1488 u_long off = (uintptr_t) (void *) value;
1492 const Elf_Sym* best = NULL;
1495 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1496 if (es->st_name == 0)
1498 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1499 if (off >= st_value) {
1500 if (off - st_value < diff) {
1501 diff = off - st_value;
1505 } else if (off - st_value == diff) {
1514 *sym = (c_linker_sym_t) best;
1520 * Look up a linker set on an ELF system.
1523 link_elf_lookup_set(linker_file_t lf, const char *name,
1524 void ***startp, void ***stopp, int *countp)
1527 linker_symval_t symval;
1529 void **start, **stop;
1530 int len, error = 0, count;
1532 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1533 setsym = malloc(len, M_LINKER, M_WAITOK);
1535 /* get address of first entry */
1536 snprintf(setsym, len, "%s%s", "__start_set_", name);
1537 error = link_elf_lookup_symbol(lf, setsym, &sym);
1540 link_elf_symbol_values(lf, sym, &symval);
1541 if (symval.value == 0) {
1545 start = (void **)symval.value;
1547 /* get address of last entry */
1548 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1549 error = link_elf_lookup_symbol(lf, setsym, &sym);
1552 link_elf_symbol_values(lf, sym, &symval);
1553 if (symval.value == 0) {
1557 stop = (void **)symval.value;
1559 /* and the number of entries */
1560 count = stop - start;
1571 free(setsym, M_LINKER);
1576 link_elf_each_function_name(linker_file_t file,
1577 int (*callback)(const char *, void *), void *opaque)
1579 elf_file_t ef = (elf_file_t)file;
1580 const Elf_Sym *symp;
1583 /* Exhaustive search */
1584 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1585 if (symp->st_value != 0 &&
1586 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1587 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1588 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1597 link_elf_each_function_nameval(linker_file_t file,
1598 linker_function_nameval_callback_t callback, void *opaque)
1600 linker_symval_t symval;
1601 elf_file_t ef = (elf_file_t)file;
1602 const Elf_Sym* symp;
1605 /* Exhaustive search */
1606 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1607 if (symp->st_value != 0 &&
1608 (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1609 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1610 error = link_elf_symbol_values(file,
1611 (c_linker_sym_t) symp, &symval);
1614 error = callback(file, i, &symval, opaque);
1623 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1625 elf_file_t ef = (elf_file_t)lf;
1627 if (symidx >= ef->nchains)
1629 return (ef->symtab + symidx);
1633 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1635 elf_file_t ef = (elf_file_t)lf;
1638 if (symidx >= ef->nchains)
1640 sym = ef->symtab + symidx;
1641 return (ef->strtab + sym->st_name);
1645 * Symbol lookup function that can be used when the symbol index is known (ie
1646 * in relocations). It uses the symbol index instead of doing a fully fledged
1647 * hash table based lookup when such is valid. For example for local symbols.
1648 * This is not only more efficient, it's also more correct. It's not always
1649 * the case that the symbol can be found through the hash table.
1652 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1654 elf_file_t ef = (elf_file_t)lf;
1657 Elf_Addr addr, start, base;
1659 /* Don't even try to lookup the symbol if the index is bogus. */
1660 if (symidx >= ef->nchains) {
1665 sym = ef->symtab + symidx;
1668 * Don't do a full lookup when the symbol is local. It may even
1669 * fail because it may not be found through the hash table.
1671 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1672 /* Force lookup failure when we have an insanity. */
1673 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1677 *res = ((Elf_Addr)ef->address + sym->st_value);
1682 * XXX we can avoid doing a hash table based lookup for global
1683 * symbols as well. This however is not always valid, so we'll
1684 * just do it the hard way for now. Performance tweaks can
1688 symbol = ef->strtab + sym->st_name;
1690 /* Force a lookup failure if the symbol name is bogus. */
1696 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1697 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1702 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1703 addr = addr - start + base;
1705 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1706 addr = addr - start + base;
1713 link_elf_reloc_local(linker_file_t lf)
1715 const Elf_Rel *rellim;
1717 const Elf_Rela *relalim;
1718 const Elf_Rela *rela;
1719 elf_file_t ef = (elf_file_t)lf;
1721 /* Perform relocations without addend if there are any: */
1722 if ((rel = ef->rel) != NULL) {
1723 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1724 while (rel < rellim) {
1725 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1726 ELF_RELOC_REL, elf_lookup);
1731 /* Perform relocations with addend if there are any: */
1732 if ((rela = ef->rela) != NULL) {
1733 relalim = (const Elf_Rela *)
1734 ((const char *)ef->rela + ef->relasize);
1735 while (rela < relalim) {
1736 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1737 ELF_RELOC_RELA, elf_lookup);
1744 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1746 elf_file_t ef = (elf_file_t)lf;
1748 *symtab = ef->ddbsymtab;
1750 if (*symtab == NULL)
1753 return (ef->ddbsymcnt);
1757 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1759 elf_file_t ef = (elf_file_t)lf;
1761 *strtab = ef->ddbstrtab;
1763 if (*strtab == NULL)
1766 return (ef->ddbstrcnt);
1769 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
1771 * Use this lookup routine when performing relocations early during boot.
1772 * The generic lookup routine depends on kobj, which is not initialized
1776 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused,
1780 const Elf_Sym *symp;
1783 ef = (elf_file_t)lf;
1784 symp = ef->symtab + symidx;
1785 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) {
1786 val = (caddr_t)ef->address + symp->st_value;
1787 *res = ((Elf_Addr (*)(void))val)();
1794 link_elf_ireloc(caddr_t kmdp)
1796 struct elf_file eff;
1801 bzero_early(ef, sizeof(*ef));
1804 ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
1807 link_elf_preload_parse_symbols(ef);
1808 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true);