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>
43 #include <sys/mutex.h>
44 #include <sys/mount.h>
47 #include <sys/namei.h>
48 #include <sys/fcntl.h>
49 #include <sys/vnode.h>
50 #include <sys/linker.h>
52 #include <machine/elf.h>
56 #include <security/mac/mac_framework.h>
59 #include <vm/vm_param.h>
61 #include <vm/vm_object.h>
62 #include <vm/vm_kern.h>
63 #include <vm/vm_extern.h>
66 #include <vm/vm_map.h>
68 #include <sys/link_elf.h>
74 #include "linker_if.h"
78 typedef struct elf_file {
79 struct linker_file lf; /* Common fields */
80 int preloaded; /* Was file pre-loaded */
81 caddr_t address; /* Relocation address */
83 vm_object_t object; /* VM object to hold file pages */
85 Elf_Dyn *dynamic; /* Symbol table etc. */
86 Elf_Hashelt nbuckets; /* DT_HASH info */
88 const Elf_Hashelt *buckets;
89 const Elf_Hashelt *chains;
91 caddr_t strtab; /* DT_STRTAB */
92 int strsz; /* DT_STRSZ */
93 const Elf_Sym *symtab; /* DT_SYMTAB */
94 Elf_Addr *got; /* DT_PLTGOT */
95 const Elf_Rel *pltrel; /* DT_JMPREL */
96 int pltrelsize; /* DT_PLTRELSZ */
97 const Elf_Rela *pltrela; /* DT_JMPREL */
98 int pltrelasize; /* DT_PLTRELSZ */
99 const Elf_Rel *rel; /* DT_REL */
100 int relsize; /* DT_RELSZ */
101 const Elf_Rela *rela; /* DT_RELA */
102 int relasize; /* DT_RELASZ */
104 const Elf_Sym *ddbsymtab; /* The symbol table we are using */
105 long ddbsymcnt; /* Number of symbols */
106 caddr_t ddbstrtab; /* String table */
107 long ddbstrcnt; /* number of bytes in string table */
108 caddr_t symbase; /* malloc'ed symbold base */
109 caddr_t strbase; /* malloc'ed string base */
110 caddr_t ctftab; /* CTF table */
111 long ctfcnt; /* number of bytes in CTF table */
112 caddr_t ctfoff; /* CTF offset table */
113 caddr_t typoff; /* Type offset table */
114 long typlen; /* Number of type entries. */
115 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */
116 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */
117 Elf_Addr pcpu_base; /* Relocated pcpu set address. */
119 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */
120 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */
121 Elf_Addr vnet_base; /* Relocated vnet set address. */
124 struct link_map gdb; /* hooks for gdb */
132 TAILQ_ENTRY(elf_set) es_link;
135 TAILQ_HEAD(elf_set_head, elf_set);
137 #include <kern/kern_ctf.c>
139 static int link_elf_link_common_finish(linker_file_t);
140 static int link_elf_link_preload(linker_class_t cls,
141 const char *, linker_file_t *);
142 static int link_elf_link_preload_finish(linker_file_t);
143 static int link_elf_load_file(linker_class_t, const char *,
145 static int link_elf_lookup_symbol(linker_file_t, const char *,
147 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
149 static int link_elf_search_symbol(linker_file_t, caddr_t,
150 c_linker_sym_t *, long *);
152 static void link_elf_unload_file(linker_file_t);
153 static void link_elf_unload_preload(linker_file_t);
154 static int link_elf_lookup_set(linker_file_t, const char *,
155 void ***, void ***, int *);
156 static int link_elf_each_function_name(linker_file_t,
157 int (*)(const char *, void *), void *);
158 static int link_elf_each_function_nameval(linker_file_t,
159 linker_function_nameval_callback_t, void *);
160 static void link_elf_reloc_local(linker_file_t);
161 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
162 static long link_elf_strtab_get(linker_file_t, caddr_t *);
163 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
165 static kobj_method_t link_elf_methods[] = {
166 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
167 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
168 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
169 KOBJMETHOD(linker_unload, link_elf_unload_file),
170 KOBJMETHOD(linker_load_file, link_elf_load_file),
171 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
172 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
173 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
174 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
175 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
176 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
177 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
178 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
182 static struct linker_class link_elf_class = {
183 #if ELF_TARG_CLASS == ELFCLASS32
188 link_elf_methods, sizeof(struct elf_file)
191 static int parse_dynamic(elf_file_t);
192 static int relocate_file(elf_file_t);
193 static int link_elf_preload_parse_symbols(elf_file_t);
195 static struct elf_set_head set_pcpu_list;
197 static struct elf_set_head set_vnet_list;
201 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base)
203 struct elf_set *set, *iter;
205 set = malloc(sizeof(*set), M_LINKER, M_WAITOK);
206 set->es_start = start;
210 TAILQ_FOREACH(iter, list, es_link) {
212 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) ||
213 (set->es_start > iter->es_start && set->es_stop > iter->es_stop),
214 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx",
215 (uintmax_t)set->es_start, (uintmax_t)set->es_stop,
216 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop));
218 if (iter->es_start > set->es_start) {
219 TAILQ_INSERT_BEFORE(iter, set, es_link);
225 TAILQ_INSERT_TAIL(list, set, es_link);
229 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base)
233 TAILQ_FOREACH(set, list, es_link) {
234 if (addr < set->es_start)
236 if (addr < set->es_stop) {
237 *start = set->es_start;
238 *base = set->es_base;
247 elf_set_delete(struct elf_set_head *list, Elf_Addr start)
251 TAILQ_FOREACH(set, list, es_link) {
252 if (start < set->es_start)
254 if (start == set->es_start) {
255 TAILQ_REMOVE(list, set, es_link);
260 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)",
265 static void r_debug_state(struct r_debug *, struct link_map *);
268 * A list of loaded modules for GDB to use for loading symbols.
270 struct r_debug r_debug;
272 #define GDB_STATE(s) do { \
273 r_debug.r_state = s; r_debug_state(NULL, NULL); \
277 * Function for the debugger to set a breakpoint on to gain control.
280 r_debug_state(struct r_debug *dummy_one __unused,
281 struct link_map *dummy_two __unused)
286 link_elf_add_gdb(struct link_map *l)
288 struct link_map *prev;
292 if (r_debug.r_map == NULL) {
297 /* Append to list. */
298 for (prev = r_debug.r_map;
299 prev->l_next != NULL;
308 link_elf_delete_gdb(struct link_map *l)
310 if (l->l_prev == NULL) {
312 if ((r_debug.r_map = l->l_next) != NULL)
313 l->l_next->l_prev = NULL;
315 /* Remove any but first. */
316 if ((l->l_prev->l_next = l->l_next) != NULL)
317 l->l_next->l_prev = l->l_prev;
323 * The kernel symbol table starts here.
325 extern struct _dynamic _DYNAMIC;
328 link_elf_error(const char *filename, const char *s)
330 if (filename == NULL)
331 printf("kldload: %s\n", s);
333 printf("kldload: %s: %s\n", filename, s);
337 link_elf_invoke_ctors(caddr_t addr, size_t size)
342 if (addr == NULL || size == 0)
344 cnt = size / sizeof(*ctor);
346 for (i = 0; i < cnt; i++) {
353 * Actions performed after linking/loading both the preloaded kernel and any
354 * modules; whether preloaded or dynamicly loaded.
357 link_elf_link_common_finish(linker_file_t lf)
360 elf_file_t ef = (elf_file_t)lf;
365 /* Notify MD code that a module is being loaded. */
366 error = elf_cpu_load_file(lf);
372 ef->gdb.l_addr = lf->address;
373 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
374 strcpy(newfilename, lf->filename);
375 ef->gdb.l_name = newfilename;
376 ef->gdb.l_ld = ef->dynamic;
377 link_elf_add_gdb(&ef->gdb);
378 GDB_STATE(RT_CONSISTENT);
382 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
386 extern vm_offset_t __startkernel;
389 link_elf_init(void* arg)
392 Elf_Addr *ctors_addrp;
393 Elf_Size *ctors_sizep;
394 caddr_t modptr, baseptr, sizeptr;
398 linker_add_class(&link_elf_class);
400 dp = (Elf_Dyn *)&_DYNAMIC;
402 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
404 modptr = preload_search_by_type("elf kernel");
405 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
408 linker_kernel_file = linker_make_file(modname, &link_elf_class);
409 if (linker_kernel_file == NULL)
410 panic("%s: Can't create linker structures for kernel",
413 ef = (elf_file_t) linker_kernel_file;
416 ef->address = (caddr_t) (__startkernel - KERNBASE);
420 #ifdef SPARSE_MAPPING
427 linker_kernel_file->address += KERNBASE;
428 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
430 if (modptr != NULL) {
432 baseptr = preload_search_info(modptr, MODINFO_ADDR);
434 linker_kernel_file->address = *(caddr_t *)baseptr;
435 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
437 linker_kernel_file->size = *(size_t *)sizeptr;
438 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
439 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
440 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
441 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
442 if (ctors_addrp != NULL && ctors_sizep != NULL) {
443 linker_kernel_file->ctors_addr = ef->address +
445 linker_kernel_file->ctors_size = *ctors_sizep;
448 (void)link_elf_preload_parse_symbols(ef);
451 r_debug.r_map = NULL;
452 r_debug.r_brk = r_debug_state;
453 r_debug.r_state = RT_CONSISTENT;
456 (void)link_elf_link_common_finish(linker_kernel_file);
457 linker_kernel_file->flags |= LINKER_FILE_LINKED;
458 TAILQ_INIT(&set_pcpu_list);
460 TAILQ_INIT(&set_vnet_list);
464 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
467 link_elf_preload_parse_symbols(elf_file_t ef)
470 caddr_t ssym, esym, base;
476 if (ef->modptr == NULL)
478 pointer = preload_search_info(ef->modptr,
479 MODINFO_METADATA | MODINFOMD_SSYM);
482 ssym = *(caddr_t *)pointer;
483 pointer = preload_search_info(ef->modptr,
484 MODINFO_METADATA | MODINFOMD_ESYM);
487 esym = *(caddr_t *)pointer;
491 symcnt = *(long *)base;
492 base += sizeof(long);
493 symtab = (Elf_Sym *)base;
494 base += roundup(symcnt, sizeof(long));
496 if (base > esym || base < ssym) {
497 printf("Symbols are corrupt!\n");
501 strcnt = *(long *)base;
502 base += sizeof(long);
504 base += roundup(strcnt, sizeof(long));
506 if (base > esym || base < ssym) {
507 printf("Symbols are corrupt!\n");
511 ef->ddbsymtab = symtab;
512 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
513 ef->ddbstrtab = strtab;
514 ef->ddbstrcnt = strcnt;
520 parse_dynamic(elf_file_t ef)
523 int plttype = DT_REL;
525 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
529 /* From src/libexec/rtld-elf/rtld.c */
530 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
531 (ef->address + dp->d_un.d_ptr);
532 ef->nbuckets = hashtab[0];
533 ef->nchains = hashtab[1];
534 ef->buckets = hashtab + 2;
535 ef->chains = ef->buckets + ef->nbuckets;
539 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
542 ef->strsz = dp->d_un.d_val;
545 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
548 if (dp->d_un.d_val != sizeof(Elf_Sym))
552 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
555 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
558 ef->relsize = dp->d_un.d_val;
561 if (dp->d_un.d_val != sizeof(Elf_Rel))
565 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
568 ef->pltrelsize = dp->d_un.d_val;
571 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
574 ef->relasize = dp->d_un.d_val;
577 if (dp->d_un.d_val != sizeof(Elf_Rela))
581 plttype = dp->d_un.d_val;
582 if (plttype != DT_REL && plttype != DT_RELA)
587 dp->d_un.d_ptr = (Elf_Addr)&r_debug;
593 if (plttype == DT_RELA) {
594 ef->pltrela = (const Elf_Rela *)ef->pltrel;
596 ef->pltrelasize = ef->pltrelsize;
600 ef->ddbsymtab = ef->symtab;
601 ef->ddbsymcnt = ef->nchains;
602 ef->ddbstrtab = ef->strtab;
603 ef->ddbstrcnt = ef->strsz;
609 parse_dpcpu(elf_file_t ef)
616 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
617 (void ***)&ef->pcpu_stop, &count);
618 /* Error just means there is no pcpu set to relocate. */
621 count *= sizeof(void *);
623 * Allocate space in the primary pcpu area. Copy in our
624 * initialization from the data section and then initialize
625 * all per-cpu storage from that.
627 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
628 if (ef->pcpu_base == 0)
630 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
631 dpcpu_copy((void *)ef->pcpu_base, count);
632 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop,
640 parse_vnet(elf_file_t ef)
647 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
648 (void ***)&ef->vnet_stop, &count);
649 /* Error just means there is no vnet data set to relocate. */
652 count *= sizeof(void *);
654 * Allocate space in the primary vnet area. Copy in our
655 * initialization from the data section and then initialize
656 * all per-vnet storage from that.
658 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
659 if (ef->vnet_base == 0)
661 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
662 vnet_data_copy((void *)ef->vnet_base, count);
663 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop,
671 link_elf_link_preload(linker_class_t cls,
672 const char* filename, linker_file_t *result)
674 Elf_Addr *ctors_addrp;
675 Elf_Size *ctors_sizep;
676 caddr_t modptr, baseptr, sizeptr, dynptr;
683 /* Look to see if we have the file preloaded */
684 modptr = preload_search_by_name(filename);
688 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
689 baseptr = preload_search_info(modptr, MODINFO_ADDR);
690 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
691 dynptr = preload_search_info(modptr,
692 MODINFO_METADATA | MODINFOMD_DYNAMIC);
694 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
695 strcmp(type, "elf module") != 0))
697 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
700 lf = linker_make_file(filename, &link_elf_class);
704 ef = (elf_file_t) lf;
707 ef->address = *(caddr_t *)baseptr;
708 #ifdef SPARSE_MAPPING
711 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
712 ef->dynamic = (Elf_Dyn *)dp;
713 lf->address = ef->address;
714 lf->size = *(size_t *)sizeptr;
716 ctors_addrp = (Elf_Addr *)preload_search_info(modptr,
717 MODINFO_METADATA | MODINFOMD_CTORS_ADDR);
718 ctors_sizep = (Elf_Size *)preload_search_info(modptr,
719 MODINFO_METADATA | MODINFOMD_CTORS_SIZE);
720 if (ctors_addrp != NULL && ctors_sizep != NULL) {
721 lf->ctors_addr = ef->address + *ctors_addrp;
722 lf->ctors_size = *ctors_sizep;
725 error = parse_dynamic(ef);
727 error = parse_dpcpu(ef);
730 error = parse_vnet(ef);
733 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
736 link_elf_reloc_local(lf);
742 link_elf_link_preload_finish(linker_file_t lf)
747 ef = (elf_file_t) lf;
748 error = relocate_file(ef);
751 (void)link_elf_preload_parse_symbols(ef);
753 return (link_elf_link_common_finish(lf));
757 link_elf_load_file(linker_class_t cls, const char* filename,
758 linker_file_t* result)
761 struct thread* td = curthread; /* XXX */
767 Elf_Phdr *segs[MAXSEGS];
775 Elf_Addr base_vlimit;
793 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
795 error = vn_open(&nd, &flags, 0, NULL);
798 NDFREE(&nd, NDF_ONLY_PNBUF);
799 if (nd.ni_vp->v_type != VREG) {
805 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
813 * Read the elf header from the file.
815 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
816 hdr = (Elf_Ehdr *)firstpage;
817 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
818 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
820 nbytes = PAGE_SIZE - resid;
829 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
830 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
831 link_elf_error(filename, "Unsupported file layout");
835 if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
836 hdr->e_version != EV_CURRENT) {
837 link_elf_error(filename, "Unsupported file version");
841 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
845 if (hdr->e_machine != ELF_TARG_MACH) {
846 link_elf_error(filename, "Unsupported machine");
852 * We rely on the program header being in the first page.
853 * This is not strictly required by the ABI specification, but
854 * it seems to always true in practice. And, it simplifies
855 * things considerably.
857 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
858 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
859 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
860 link_elf_error(filename, "Unreadable program headers");
863 * Scan the program header entries, and save key information.
865 * We rely on there being exactly two load segments, text and data,
868 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
869 phlimit = phdr + hdr->e_phnum;
873 while (phdr < phlimit) {
874 switch (phdr->p_type) {
876 if (nsegs == MAXSEGS) {
877 link_elf_error(filename, "Too many sections");
882 * XXX: We just trust they come in right order ??
904 link_elf_error(filename, "Object is not dynamically-linked");
909 link_elf_error(filename, "No sections");
915 * Allocate the entire address space of the object, to stake
916 * out our contiguous region, and to establish the base
917 * address for relocation.
919 base_offset = trunc_page(segs[0]->p_offset);
920 base_vaddr = trunc_page(segs[0]->p_vaddr);
921 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
922 segs[nsegs - 1]->p_memsz);
923 mapsize = base_vlimit - base_vaddr;
925 lf = linker_make_file(filename, &link_elf_class);
931 ef = (elf_file_t) lf;
932 #ifdef SPARSE_MAPPING
933 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
934 if (ef->object == NULL) {
938 ef->address = (caddr_t) vm_map_min(kernel_map);
939 error = vm_map_find(kernel_map, ef->object, 0,
940 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE,
941 VM_PROT_ALL, VM_PROT_ALL, 0);
943 vm_object_deallocate(ef->object);
948 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
950 mapbase = ef->address;
953 * Read the text and data sections and zero the bss.
955 for (i = 0; i < nsegs; i++) {
956 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
957 error = vn_rdwr(UIO_READ, nd.ni_vp,
958 segbase, segs[i]->p_filesz, segs[i]->p_offset,
959 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
963 bzero(segbase + segs[i]->p_filesz,
964 segs[i]->p_memsz - segs[i]->p_filesz);
966 #ifdef SPARSE_MAPPING
968 * Wire down the pages
970 error = vm_map_wire(kernel_map,
971 (vm_offset_t) segbase,
972 (vm_offset_t) segbase + segs[i]->p_memsz,
973 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
974 if (error != KERN_SUCCESS) {
982 /* Update profiling information with the new text segment. */
984 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
989 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
991 lf->address = ef->address;
994 error = parse_dynamic(ef);
997 error = parse_dpcpu(ef);
1001 error = parse_vnet(ef);
1005 link_elf_reloc_local(lf);
1007 VOP_UNLOCK(nd.ni_vp, 0);
1008 error = linker_load_dependencies(lf);
1009 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
1012 error = relocate_file(ef);
1017 * Try and load the symbol table if it's present. (you can
1020 nbytes = hdr->e_shnum * hdr->e_shentsize;
1021 if (nbytes == 0 || hdr->e_shoff == 0)
1023 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1024 error = vn_rdwr(UIO_READ, nd.ni_vp,
1025 (caddr_t)shdr, nbytes, hdr->e_shoff,
1026 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1031 /* Read section string table */
1032 shstrindex = hdr->e_shstrndx;
1033 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB &&
1034 shdr[shstrindex].sh_size != 0) {
1035 nbytes = shdr[shstrindex].sh_size;
1036 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
1037 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes,
1038 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
1039 td->td_ucred, NOCRED, &resid, td);
1046 for (i = 0; i < hdr->e_shnum; i++) {
1047 if (shdr[i].sh_type == SHT_SYMTAB) {
1049 symstrindex = shdr[i].sh_link;
1050 } else if (shstrs != NULL && shdr[i].sh_name != 0 &&
1051 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) {
1052 /* Record relocated address and size of .ctors. */
1053 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr;
1054 lf->ctors_size = shdr[i].sh_size;
1057 if (symtabindex < 0 || symstrindex < 0)
1060 symcnt = shdr[symtabindex].sh_size;
1061 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
1062 strcnt = shdr[symstrindex].sh_size;
1063 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
1065 error = vn_rdwr(UIO_READ, nd.ni_vp,
1066 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
1067 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1071 error = vn_rdwr(UIO_READ, nd.ni_vp,
1072 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
1073 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1078 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
1079 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
1080 ef->ddbstrcnt = strcnt;
1081 ef->ddbstrtab = ef->strbase;
1084 error = link_elf_link_common_finish(lf);
1091 VOP_UNLOCK(nd.ni_vp, 0);
1092 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
1093 if (error != 0 && lf != NULL)
1094 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1095 free(shdr, M_LINKER);
1096 free(firstpage, M_LINKER);
1097 free(shstrs, M_LINKER);
1103 elf_relocaddr(linker_file_t lf, Elf_Addr x)
1107 ef = (elf_file_t)lf;
1108 if (x >= ef->pcpu_start && x < ef->pcpu_stop)
1109 return ((x - ef->pcpu_start) + ef->pcpu_base);
1111 if (x >= ef->vnet_start && x < ef->vnet_stop)
1112 return ((x - ef->vnet_start) + ef->vnet_base);
1119 link_elf_unload_file(linker_file_t file)
1121 elf_file_t ef = (elf_file_t) file;
1123 if (ef->pcpu_base != 0) {
1124 dpcpu_free((void *)ef->pcpu_base,
1125 ef->pcpu_stop - ef->pcpu_start);
1126 elf_set_delete(&set_pcpu_list, ef->pcpu_start);
1129 if (ef->vnet_base != 0) {
1130 vnet_data_free((void *)ef->vnet_base,
1131 ef->vnet_stop - ef->vnet_start);
1132 elf_set_delete(&set_vnet_list, ef->vnet_start);
1136 if (ef->gdb.l_ld != NULL) {
1137 GDB_STATE(RT_DELETE);
1138 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
1139 link_elf_delete_gdb(&ef->gdb);
1140 GDB_STATE(RT_CONSISTENT);
1144 /* Notify MD code that a module is being unloaded. */
1145 elf_cpu_unload_file(file);
1147 if (ef->preloaded) {
1148 link_elf_unload_preload(file);
1152 #ifdef SPARSE_MAPPING
1153 if (ef->object != NULL) {
1154 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1155 (vm_offset_t) ef->address
1156 + (ef->object->size << PAGE_SHIFT));
1159 free(ef->address, M_LINKER);
1161 free(ef->symbase, M_LINKER);
1162 free(ef->strbase, M_LINKER);
1163 free(ef->ctftab, M_LINKER);
1164 free(ef->ctfoff, M_LINKER);
1165 free(ef->typoff, M_LINKER);
1169 link_elf_unload_preload(linker_file_t file)
1171 if (file->filename != NULL)
1172 preload_delete_name(file->filename);
1176 symbol_name(elf_file_t ef, Elf_Size r_info)
1180 if (ELF_R_SYM(r_info)) {
1181 ref = ef->symtab + ELF_R_SYM(r_info);
1182 return (ef->strtab + ref->st_name);
1188 relocate_file(elf_file_t ef)
1190 const Elf_Rel *rellim;
1192 const Elf_Rela *relalim;
1193 const Elf_Rela *rela;
1194 const char *symname;
1196 /* Perform relocations without addend if there are any: */
1199 rellim = (const Elf_Rel *)
1200 ((const char *)ef->rel + ef->relsize);
1201 while (rel < rellim) {
1202 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1203 ELF_RELOC_REL, elf_lookup)) {
1204 symname = symbol_name(ef, rel->r_info);
1205 printf("link_elf: symbol %s undefined\n", symname);
1212 /* Perform relocations with addend if there are any: */
1215 relalim = (const Elf_Rela *)
1216 ((const char *)ef->rela + ef->relasize);
1217 while (rela < relalim) {
1218 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1219 ELF_RELOC_RELA, elf_lookup)) {
1220 symname = symbol_name(ef, rela->r_info);
1221 printf("link_elf: symbol %s undefined\n",
1229 /* Perform PLT relocations without addend if there are any: */
1232 rellim = (const Elf_Rel *)
1233 ((const char *)ef->pltrel + ef->pltrelsize);
1234 while (rel < rellim) {
1235 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
1236 ELF_RELOC_REL, elf_lookup)) {
1237 symname = symbol_name(ef, rel->r_info);
1238 printf("link_elf: symbol %s undefined\n",
1246 /* Perform relocations with addend if there are any: */
1249 relalim = (const Elf_Rela *)
1250 ((const char *)ef->pltrela + ef->pltrelasize);
1251 while (rela < relalim) {
1252 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
1253 ELF_RELOC_RELA, elf_lookup)) {
1254 symname = symbol_name(ef, rela->r_info);
1255 printf("link_elf: symbol %s undefined\n",
1267 * Hash function for symbol table lookup. Don't even think about changing
1268 * this. It is specified by the System V ABI.
1270 static unsigned long
1271 elf_hash(const char *name)
1273 const unsigned char *p = (const unsigned char *) name;
1274 unsigned long h = 0;
1277 while (*p != '\0') {
1278 h = (h << 4) + *p++;
1279 if ((g = h & 0xf0000000) != 0)
1287 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1289 elf_file_t ef = (elf_file_t) lf;
1290 unsigned long symnum;
1291 const Elf_Sym* symp;
1296 /* If we don't have a hash, bail. */
1297 if (ef->buckets == NULL || ef->nbuckets == 0) {
1298 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1302 /* First, search hashed global symbols */
1303 hash = elf_hash(name);
1304 symnum = ef->buckets[hash % ef->nbuckets];
1306 while (symnum != STN_UNDEF) {
1307 if (symnum >= ef->nchains) {
1308 printf("%s: corrupt symbol table\n", __func__);
1312 symp = ef->symtab + symnum;
1313 if (symp->st_name == 0) {
1314 printf("%s: corrupt symbol table\n", __func__);
1318 strp = ef->strtab + symp->st_name;
1320 if (strcmp(name, strp) == 0) {
1321 if (symp->st_shndx != SHN_UNDEF ||
1322 (symp->st_value != 0 &&
1323 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1324 *sym = (c_linker_sym_t) symp;
1330 symnum = ef->chains[symnum];
1333 /* If we have not found it, look at the full table (if loaded) */
1334 if (ef->symtab == ef->ddbsymtab)
1337 /* Exhaustive search */
1338 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1339 strp = ef->ddbstrtab + symp->st_name;
1340 if (strcmp(name, strp) == 0) {
1341 if (symp->st_shndx != SHN_UNDEF ||
1342 (symp->st_value != 0 &&
1343 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1344 *sym = (c_linker_sym_t) symp;
1355 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1356 linker_symval_t *symval)
1358 elf_file_t ef = (elf_file_t) lf;
1359 const Elf_Sym* es = (const Elf_Sym*) sym;
1361 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1362 symval->name = ef->strtab + es->st_name;
1363 symval->value = (caddr_t) ef->address + es->st_value;
1364 symval->size = es->st_size;
1367 if (ef->symtab == ef->ddbsymtab)
1369 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1370 symval->name = ef->ddbstrtab + es->st_name;
1371 symval->value = (caddr_t) ef->address + es->st_value;
1372 symval->size = es->st_size;
1379 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1380 c_linker_sym_t *sym, long *diffp)
1382 elf_file_t ef = (elf_file_t) lf;
1383 u_long off = (uintptr_t) (void *) value;
1387 const Elf_Sym* best = NULL;
1390 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1391 if (es->st_name == 0)
1393 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1394 if (off >= st_value) {
1395 if (off - st_value < diff) {
1396 diff = off - st_value;
1400 } else if (off - st_value == diff) {
1409 *sym = (c_linker_sym_t) best;
1415 * Look up a linker set on an ELF system.
1418 link_elf_lookup_set(linker_file_t lf, const char *name,
1419 void ***startp, void ***stopp, int *countp)
1422 linker_symval_t symval;
1424 void **start, **stop;
1425 int len, error = 0, count;
1427 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1428 setsym = malloc(len, M_LINKER, M_WAITOK);
1430 /* get address of first entry */
1431 snprintf(setsym, len, "%s%s", "__start_set_", name);
1432 error = link_elf_lookup_symbol(lf, setsym, &sym);
1435 link_elf_symbol_values(lf, sym, &symval);
1436 if (symval.value == 0) {
1440 start = (void **)symval.value;
1442 /* get address of last entry */
1443 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1444 error = link_elf_lookup_symbol(lf, setsym, &sym);
1447 link_elf_symbol_values(lf, sym, &symval);
1448 if (symval.value == 0) {
1452 stop = (void **)symval.value;
1454 /* and the number of entries */
1455 count = stop - start;
1466 free(setsym, M_LINKER);
1471 link_elf_each_function_name(linker_file_t file,
1472 int (*callback)(const char *, void *), void *opaque)
1474 elf_file_t ef = (elf_file_t)file;
1475 const Elf_Sym *symp;
1478 /* Exhaustive search */
1479 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1480 if (symp->st_value != 0 &&
1481 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1482 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1491 link_elf_each_function_nameval(linker_file_t file,
1492 linker_function_nameval_callback_t callback, void *opaque)
1494 linker_symval_t symval;
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 error = link_elf_symbol_values(file,
1504 (c_linker_sym_t) symp, &symval);
1507 error = callback(file, i, &symval, opaque);
1516 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1518 elf_file_t ef = (elf_file_t)lf;
1520 if (symidx >= ef->nchains)
1522 return (ef->symtab + symidx);
1526 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1528 elf_file_t ef = (elf_file_t)lf;
1531 if (symidx >= ef->nchains)
1533 sym = ef->symtab + symidx;
1534 return (ef->strtab + sym->st_name);
1538 * Symbol lookup function that can be used when the symbol index is known (ie
1539 * in relocations). It uses the symbol index instead of doing a fully fledged
1540 * hash table based lookup when such is valid. For example for local symbols.
1541 * This is not only more efficient, it's also more correct. It's not always
1542 * the case that the symbol can be found through the hash table.
1545 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1547 elf_file_t ef = (elf_file_t)lf;
1550 Elf_Addr addr, start, base;
1552 /* Don't even try to lookup the symbol if the index is bogus. */
1553 if (symidx >= ef->nchains) {
1558 sym = ef->symtab + symidx;
1561 * Don't do a full lookup when the symbol is local. It may even
1562 * fail because it may not be found through the hash table.
1564 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1565 /* Force lookup failure when we have an insanity. */
1566 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
1570 *res = ((Elf_Addr)ef->address + sym->st_value);
1575 * XXX we can avoid doing a hash table based lookup for global
1576 * symbols as well. This however is not always valid, so we'll
1577 * just do it the hard way for now. Performance tweaks can
1581 symbol = ef->strtab + sym->st_name;
1583 /* Force a lookup failure if the symbol name is bogus. */
1589 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1590 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1595 if (elf_set_find(&set_pcpu_list, addr, &start, &base))
1596 addr = addr - start + base;
1598 else if (elf_set_find(&set_vnet_list, addr, &start, &base))
1599 addr = addr - start + base;
1606 link_elf_reloc_local(linker_file_t lf)
1608 const Elf_Rel *rellim;
1610 const Elf_Rela *relalim;
1611 const Elf_Rela *rela;
1612 elf_file_t ef = (elf_file_t)lf;
1614 /* Perform relocations without addend if there are any: */
1615 if ((rel = ef->rel) != NULL) {
1616 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1617 while (rel < rellim) {
1618 elf_reloc_local(lf, (Elf_Addr)ef->address, rel,
1619 ELF_RELOC_REL, elf_lookup);
1624 /* Perform relocations with addend if there are any: */
1625 if ((rela = ef->rela) != NULL) {
1626 relalim = (const Elf_Rela *)
1627 ((const char *)ef->rela + ef->relasize);
1628 while (rela < relalim) {
1629 elf_reloc_local(lf, (Elf_Addr)ef->address, rela,
1630 ELF_RELOC_RELA, elf_lookup);
1637 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1639 elf_file_t ef = (elf_file_t)lf;
1641 *symtab = ef->ddbsymtab;
1643 if (*symtab == NULL)
1646 return (ef->ddbsymcnt);
1650 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1652 elf_file_t ef = (elf_file_t)lf;
1654 *strtab = ef->ddbstrtab;
1656 if (*strtab == NULL)
1659 return (ef->ddbstrcnt);