2 * Copyright (c) 1998-2000 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/systm.h>
39 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/mutex.h>
43 #include <sys/mount.h>
45 #include <sys/namei.h>
46 #include <sys/fcntl.h>
47 #include <sys/vnode.h>
48 #include <sys/linker.h>
50 #include <machine/elf.h>
52 #include <security/mac/mac_framework.h>
55 #include <vm/vm_param.h>
57 #include <vm/vm_object.h>
58 #include <vm/vm_kern.h>
59 #include <vm/vm_extern.h>
62 #include <vm/vm_map.h>
64 #include <sys/link_elf.h>
70 #include "linker_if.h"
74 typedef struct elf_file {
75 struct linker_file lf; /* Common fields */
76 int preloaded; /* Was file pre-loaded */
77 caddr_t address; /* Relocation address */
79 vm_object_t object; /* VM object to hold file pages */
81 Elf_Dyn* dynamic; /* Symbol table etc. */
82 Elf_Hashelt nbuckets; /* DT_HASH info */
84 const Elf_Hashelt* buckets;
85 const Elf_Hashelt* chains;
87 caddr_t strtab; /* DT_STRTAB */
88 int strsz; /* DT_STRSZ */
89 const Elf_Sym* symtab; /* DT_SYMTAB */
90 Elf_Addr* got; /* DT_PLTGOT */
91 const Elf_Rel* pltrel; /* DT_JMPREL */
92 int pltrelsize; /* DT_PLTRELSZ */
93 const Elf_Rela* pltrela; /* DT_JMPREL */
94 int pltrelasize; /* DT_PLTRELSZ */
95 const Elf_Rel* rel; /* DT_REL */
96 int relsize; /* DT_RELSZ */
97 const Elf_Rela* rela; /* DT_RELA */
98 int relasize; /* DT_RELASZ */
100 const Elf_Sym* ddbsymtab; /* The symbol table we are using */
101 long ddbsymcnt; /* Number of symbols */
102 caddr_t ddbstrtab; /* String table */
103 long ddbstrcnt; /* number of bytes in string table */
104 caddr_t symbase; /* malloc'ed symbold base */
105 caddr_t strbase; /* malloc'ed string base */
106 caddr_t ctftab; /* CTF table */
107 long ctfcnt; /* number of bytes in CTF table */
108 caddr_t ctfoff; /* CTF offset table */
109 caddr_t typoff; /* Type offset table */
110 long typlen; /* Number of type entries. */
112 struct link_map gdb; /* hooks for gdb */
116 #include <kern/kern_ctf.c>
118 static int link_elf_link_common_finish(linker_file_t);
119 static int link_elf_link_preload(linker_class_t cls,
120 const char*, linker_file_t*);
121 static int link_elf_link_preload_finish(linker_file_t);
122 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*);
123 static int link_elf_lookup_symbol(linker_file_t, const char*,
125 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
126 static int link_elf_search_symbol(linker_file_t, caddr_t value,
127 c_linker_sym_t* sym, long* diffp);
129 static void link_elf_unload_file(linker_file_t);
130 static void link_elf_unload_preload(linker_file_t);
131 static int link_elf_lookup_set(linker_file_t, const char *,
132 void ***, void ***, int *);
133 static int link_elf_each_function_name(linker_file_t,
134 int (*)(const char *, void *),
136 static int link_elf_each_function_nameval(linker_file_t,
137 linker_function_nameval_callback_t,
139 static void link_elf_reloc_local(linker_file_t);
140 static Elf_Addr elf_lookup(linker_file_t lf, Elf_Size symidx, int deps);
142 static kobj_method_t link_elf_methods[] = {
143 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
144 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
145 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
146 KOBJMETHOD(linker_unload, link_elf_unload_file),
147 KOBJMETHOD(linker_load_file, link_elf_load_file),
148 KOBJMETHOD(linker_link_preload, link_elf_link_preload),
149 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
150 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
151 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
152 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
153 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
157 static struct linker_class link_elf_class = {
158 #if ELF_TARG_CLASS == ELFCLASS32
163 link_elf_methods, sizeof(struct elf_file)
166 static int parse_dynamic(elf_file_t ef);
167 static int relocate_file(elf_file_t ef);
168 static int link_elf_preload_parse_symbols(elf_file_t ef);
171 static void r_debug_state(struct r_debug *dummy_one,
172 struct link_map *dummy_two);
175 * A list of loaded modules for GDB to use for loading symbols.
177 struct r_debug r_debug;
179 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL);
182 * Function for the debugger to set a breakpoint on to gain control.
185 r_debug_state(struct r_debug *dummy_one __unused,
186 struct link_map *dummy_two __unused)
191 link_elf_add_gdb(struct link_map *l)
193 struct link_map *prev;
197 if (r_debug.r_map == NULL) {
202 /* Append to list. */
203 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
211 link_elf_delete_gdb(struct link_map *l)
213 if (l->l_prev == NULL) {
215 if ((r_debug.r_map = l->l_next) != NULL)
216 l->l_next->l_prev = NULL;
218 /* Remove any but first. */
219 if ((l->l_prev->l_next = l->l_next) != NULL)
220 l->l_next->l_prev = l->l_prev;
226 Elf_Addr link_elf_get_gp(linker_file_t);
230 * The kernel symbol table starts here.
232 extern struct _dynamic _DYNAMIC;
235 link_elf_error(const char *filename, const char *s)
237 if (filename == NULL)
238 printf("kldload: %s\n", s);
240 printf("kldload: %s: %s\n", filename, s);
244 * Actions performed after linking/loading both the preloaded kernel and any
245 * modules; whether preloaded or dynamicly loaded.
248 link_elf_link_common_finish(linker_file_t lf)
251 elf_file_t ef = (elf_file_t)lf;
256 /* Notify MD code that a module is being loaded. */
257 error = elf_cpu_load_file(lf);
263 ef->gdb.l_addr = lf->address;
264 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
265 strcpy(newfilename, lf->filename);
266 ef->gdb.l_name = newfilename;
267 ef->gdb.l_ld = ef->dynamic;
268 link_elf_add_gdb(&ef->gdb);
269 GDB_STATE(RT_CONSISTENT);
276 link_elf_init(void* arg)
279 caddr_t modptr, baseptr, sizeptr;
283 linker_add_class(&link_elf_class);
285 dp = (Elf_Dyn*) &_DYNAMIC;
287 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
289 modptr = preload_search_by_type("elf kernel");
291 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
294 linker_kernel_file = linker_make_file(modname, &link_elf_class);
295 if (linker_kernel_file == NULL)
296 panic("link_elf_init: Can't create linker structures for kernel");
298 ef = (elf_file_t) linker_kernel_file;
301 #ifdef SPARSE_MAPPING
308 linker_kernel_file->address = (caddr_t) KERNBASE;
309 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
313 baseptr = preload_search_info(modptr, MODINFO_ADDR);
315 linker_kernel_file->address = *(caddr_t *)baseptr;
316 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
318 linker_kernel_file->size = *(size_t *)sizeptr;
320 (void)link_elf_preload_parse_symbols(ef);
323 r_debug.r_map = NULL;
324 r_debug.r_brk = r_debug_state;
325 r_debug.r_state = RT_CONSISTENT;
328 (void)link_elf_link_common_finish(linker_kernel_file);
329 linker_kernel_file->flags |= LINKER_FILE_LINKED;
332 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
335 link_elf_preload_parse_symbols(elf_file_t ef)
338 caddr_t ssym, esym, base;
344 if (ef->modptr == NULL)
346 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
349 ssym = *(caddr_t *)pointer;
350 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
353 esym = *(caddr_t *)pointer;
357 symcnt = *(long *)base;
358 base += sizeof(long);
359 symtab = (Elf_Sym *)base;
360 base += roundup(symcnt, sizeof(long));
362 if (base > esym || base < ssym) {
363 printf("Symbols are corrupt!\n");
367 strcnt = *(long *)base;
368 base += sizeof(long);
370 base += roundup(strcnt, sizeof(long));
372 if (base > esym || base < ssym) {
373 printf("Symbols are corrupt!\n");
377 ef->ddbsymtab = symtab;
378 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
379 ef->ddbstrtab = strtab;
380 ef->ddbstrcnt = strcnt;
386 parse_dynamic(elf_file_t ef)
389 int plttype = DT_REL;
391 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
395 /* From src/libexec/rtld-elf/rtld.c */
396 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
397 (ef->address + dp->d_un.d_ptr);
398 ef->nbuckets = hashtab[0];
399 ef->nchains = hashtab[1];
400 ef->buckets = hashtab + 2;
401 ef->chains = ef->buckets + ef->nbuckets;
405 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
408 ef->strsz = dp->d_un.d_val;
411 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
414 if (dp->d_un.d_val != sizeof(Elf_Sym))
418 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
421 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
424 ef->relsize = dp->d_un.d_val;
427 if (dp->d_un.d_val != sizeof(Elf_Rel))
431 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
434 ef->pltrelsize = dp->d_un.d_val;
437 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
440 ef->relasize = dp->d_un.d_val;
443 if (dp->d_un.d_val != sizeof(Elf_Rela))
447 plttype = dp->d_un.d_val;
448 if (plttype != DT_REL && plttype != DT_RELA)
453 dp->d_un.d_ptr = (Elf_Addr) &r_debug;
459 if (plttype == DT_RELA) {
460 ef->pltrela = (const Elf_Rela *) ef->pltrel;
462 ef->pltrelasize = ef->pltrelsize;
466 ef->ddbsymtab = ef->symtab;
467 ef->ddbsymcnt = ef->nchains;
468 ef->ddbstrtab = ef->strtab;
469 ef->ddbstrcnt = ef->strsz;
475 link_elf_link_preload(linker_class_t cls,
476 const char* filename, linker_file_t *result)
478 caddr_t modptr, baseptr, sizeptr, dynptr;
485 /* Look to see if we have the file preloaded */
486 modptr = preload_search_by_name(filename);
490 type = (char *)preload_search_info(modptr, MODINFO_TYPE);
491 baseptr = preload_search_info(modptr, MODINFO_ADDR);
492 sizeptr = preload_search_info(modptr, MODINFO_SIZE);
493 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
495 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
496 strcmp(type, "elf module") != 0))
498 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
501 lf = linker_make_file(filename, &link_elf_class);
506 ef = (elf_file_t) lf;
509 ef->address = *(caddr_t *)baseptr;
510 #ifdef SPARSE_MAPPING
513 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
514 ef->dynamic = (Elf_Dyn *)dp;
515 lf->address = ef->address;
516 lf->size = *(size_t *)sizeptr;
518 error = parse_dynamic(ef);
520 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
523 link_elf_reloc_local(lf);
529 link_elf_link_preload_finish(linker_file_t lf)
534 ef = (elf_file_t) lf;
535 #if 0 /* this will be more trouble than it's worth for now */
536 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
537 if (dp->d_tag != DT_NEEDED)
539 modname = ef->strtab + dp->d_un.d_val;
540 error = linker_load_module(modname, lf);
545 error = relocate_file(ef);
548 (void)link_elf_preload_parse_symbols(ef);
550 return (link_elf_link_common_finish(lf));
554 link_elf_load_file(linker_class_t cls, const char* filename,
555 linker_file_t* result)
558 struct thread* td = curthread; /* XXX */
564 Elf_Phdr *segs[MAXSEGS];
572 Elf_Addr base_vlimit;
587 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
589 error = vn_open(&nd, &flags, 0, NULL);
592 vfslocked = NDHASGIANT(&nd);
593 NDFREE(&nd, NDF_ONLY_PNBUF);
594 if (nd.ni_vp->v_type != VREG) {
600 error = mac_check_kld_load(curthread->td_ucred, nd.ni_vp);
608 * Read the elf header from the file.
610 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
611 if (firstpage == NULL) {
615 hdr = (Elf_Ehdr *)firstpage;
616 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
617 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
619 nbytes = PAGE_SIZE - resid;
628 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
629 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
630 link_elf_error(filename, "Unsupported file layout");
634 if (hdr->e_ident[EI_VERSION] != EV_CURRENT
635 || hdr->e_version != EV_CURRENT) {
636 link_elf_error(filename, "Unsupported file version");
640 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
641 link_elf_error(filename, "Unsupported file type");
645 if (hdr->e_machine != ELF_TARG_MACH) {
646 link_elf_error(filename, "Unsupported machine");
652 * We rely on the program header being in the first page. This is
653 * not strictly required by the ABI specification, but it seems to
654 * always true in practice. And, it simplifies things considerably.
656 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
657 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
658 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
659 link_elf_error(filename, "Unreadable program headers");
662 * Scan the program header entries, and save key information.
664 * We rely on there being exactly two load segments, text and data,
667 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
668 phlimit = phdr + hdr->e_phnum;
672 while (phdr < phlimit) {
673 switch (phdr->p_type) {
676 if (nsegs == MAXSEGS) {
677 link_elf_error(filename, "Too many sections");
682 * XXX: We just trust they come in right order ??
697 link_elf_error(filename, "Unsupported file type");
705 link_elf_error(filename, "Object is not dynamically-linked");
710 link_elf_error(filename, "No sections");
716 * Allocate the entire address space of the object, to stake out our
717 * contiguous region, and to establish the base address for relocation.
719 base_offset = trunc_page(segs[0]->p_offset);
720 base_vaddr = trunc_page(segs[0]->p_vaddr);
721 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr +
722 segs[nsegs - 1]->p_memsz);
723 mapsize = base_vlimit - base_vaddr;
725 lf = linker_make_file(filename, &link_elf_class);
731 ef = (elf_file_t) lf;
732 #ifdef SPARSE_MAPPING
733 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
734 if (ef->object == NULL) {
738 ef->address = (caddr_t) vm_map_min(kernel_map);
739 error = vm_map_find(kernel_map, ef->object, 0,
740 (vm_offset_t *) &ef->address,
742 VM_PROT_ALL, VM_PROT_ALL, 0);
744 vm_object_deallocate(ef->object);
749 ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
755 mapbase = ef->address;
758 * Read the text and data sections and zero the bss.
760 for (i = 0; i < nsegs; i++) {
761 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
762 error = vn_rdwr(UIO_READ, nd.ni_vp,
763 segbase, segs[i]->p_filesz, segs[i]->p_offset,
764 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
769 bzero(segbase + segs[i]->p_filesz,
770 segs[i]->p_memsz - segs[i]->p_filesz);
772 #ifdef SPARSE_MAPPING
774 * Wire down the pages
776 error = vm_map_wire(kernel_map,
777 (vm_offset_t) segbase,
778 (vm_offset_t) segbase + segs[i]->p_memsz,
779 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
780 if (error != KERN_SUCCESS) {
788 /* Update profiling information with the new text segment. */
790 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
795 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
797 lf->address = ef->address;
800 error = parse_dynamic(ef);
803 link_elf_reloc_local(lf);
805 VOP_UNLOCK(nd.ni_vp, 0, td);
806 error = linker_load_dependencies(lf);
807 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY, td);
810 #if 0 /* this will be more trouble than it's worth for now */
811 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
812 if (dp->d_tag != DT_NEEDED)
814 modname = ef->strtab + dp->d_un.d_val;
815 error = linker_load_module(modname, lf);
820 error = relocate_file(ef);
824 /* Try and load the symbol table if it's present. (you can strip it!) */
825 nbytes = hdr->e_shnum * hdr->e_shentsize;
826 if (nbytes == 0 || hdr->e_shoff == 0)
828 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
833 error = vn_rdwr(UIO_READ, nd.ni_vp,
834 (caddr_t)shdr, nbytes, hdr->e_shoff,
835 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
841 for (i = 0; i < hdr->e_shnum; i++) {
842 if (shdr[i].sh_type == SHT_SYMTAB) {
844 symstrindex = shdr[i].sh_link;
847 if (symtabindex < 0 || symstrindex < 0)
850 symcnt = shdr[symtabindex].sh_size;
851 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
852 strcnt = shdr[symstrindex].sh_size;
853 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
855 if (ef->symbase == NULL || ef->strbase == NULL) {
859 error = vn_rdwr(UIO_READ, nd.ni_vp,
860 ef->symbase, symcnt, shdr[symtabindex].sh_offset,
861 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
865 error = vn_rdwr(UIO_READ, nd.ni_vp,
866 ef->strbase, strcnt, shdr[symstrindex].sh_offset,
867 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
872 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
873 ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
874 ef->ddbstrcnt = strcnt;
875 ef->ddbstrtab = ef->strbase;
877 error = link_elf_link_common_finish(lf);
887 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
889 free(shdr, M_LINKER);
891 free(firstpage, M_LINKER);
892 VOP_UNLOCK(nd.ni_vp, 0, td);
893 vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
894 VFS_UNLOCK_GIANT(vfslocked);
900 link_elf_unload_file(linker_file_t file)
902 elf_file_t ef = (elf_file_t) file;
906 GDB_STATE(RT_DELETE);
907 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
908 link_elf_delete_gdb(&ef->gdb);
909 GDB_STATE(RT_CONSISTENT);
913 /* Notify MD code that a module is being unloaded. */
914 elf_cpu_unload_file(file);
917 link_elf_unload_preload(file);
921 #ifdef SPARSE_MAPPING
923 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
924 (vm_offset_t) ef->address
925 + (ef->object->size << PAGE_SHIFT));
929 free(ef->address, M_LINKER);
932 free(ef->symbase, M_LINKER);
934 free(ef->strbase, M_LINKER);
936 free(ef->ctftab, M_LINKER);
938 free(ef->ctfoff, M_LINKER);
940 free(ef->typoff, M_LINKER);
944 link_elf_unload_preload(linker_file_t file)
947 preload_delete_name(file->filename);
951 symbol_name(elf_file_t ef, Elf_Size r_info)
955 if (ELF_R_SYM(r_info)) {
956 ref = ef->symtab + ELF_R_SYM(r_info);
957 return ef->strtab + ref->st_name;
963 relocate_file(elf_file_t ef)
965 const Elf_Rel *rellim;
967 const Elf_Rela *relalim;
968 const Elf_Rela *rela;
971 /* Perform relocations without addend if there are any: */
974 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
975 while (rel < rellim) {
976 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
978 symname = symbol_name(ef, rel->r_info);
979 printf("link_elf: symbol %s undefined\n", symname);
986 /* Perform relocations with addend if there are any: */
989 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
990 while (rela < relalim) {
991 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
993 symname = symbol_name(ef, rela->r_info);
994 printf("link_elf: symbol %s undefined\n", symname);
1001 /* Perform PLT relocations without addend if there are any: */
1004 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
1005 while (rel < rellim) {
1006 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1008 symname = symbol_name(ef, rel->r_info);
1009 printf("link_elf: symbol %s undefined\n", symname);
1016 /* Perform relocations with addend if there are any: */
1019 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
1020 while (rela < relalim) {
1021 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
1023 symname = symbol_name(ef, rela->r_info);
1024 printf("link_elf: symbol %s undefined\n", symname);
1035 * Hash function for symbol table lookup. Don't even think about changing
1036 * this. It is specified by the System V ABI.
1038 static unsigned long
1039 elf_hash(const char *name)
1041 const unsigned char *p = (const unsigned char *) name;
1042 unsigned long h = 0;
1045 while (*p != '\0') {
1046 h = (h << 4) + *p++;
1047 if ((g = h & 0xf0000000) != 0)
1055 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
1057 elf_file_t ef = (elf_file_t) lf;
1058 unsigned long symnum;
1059 const Elf_Sym* symp;
1064 /* If we don't have a hash, bail. */
1065 if (ef->buckets == NULL || ef->nbuckets == 0) {
1066 printf("link_elf_lookup_symbol: missing symbol hash table\n");
1070 /* First, search hashed global symbols */
1071 hash = elf_hash(name);
1072 symnum = ef->buckets[hash % ef->nbuckets];
1074 while (symnum != STN_UNDEF) {
1075 if (symnum >= ef->nchains) {
1076 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1080 symp = ef->symtab + symnum;
1081 if (symp->st_name == 0) {
1082 printf("link_elf_lookup_symbol: corrupt symbol table\n");
1086 strp = ef->strtab + symp->st_name;
1088 if (strcmp(name, strp) == 0) {
1089 if (symp->st_shndx != SHN_UNDEF ||
1090 (symp->st_value != 0 &&
1091 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1092 *sym = (c_linker_sym_t) symp;
1098 symnum = ef->chains[symnum];
1101 /* If we have not found it, look at the full table (if loaded) */
1102 if (ef->symtab == ef->ddbsymtab)
1105 /* Exhaustive search */
1106 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1107 strp = ef->ddbstrtab + symp->st_name;
1108 if (strcmp(name, strp) == 0) {
1109 if (symp->st_shndx != SHN_UNDEF ||
1110 (symp->st_value != 0 &&
1111 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
1112 *sym = (c_linker_sym_t) symp;
1123 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
1125 elf_file_t ef = (elf_file_t) lf;
1126 const Elf_Sym* es = (const Elf_Sym*) sym;
1128 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
1129 symval->name = ef->strtab + es->st_name;
1130 symval->value = (caddr_t) ef->address + es->st_value;
1131 symval->size = es->st_size;
1134 if (ef->symtab == ef->ddbsymtab)
1136 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1137 symval->name = ef->ddbstrtab + es->st_name;
1138 symval->value = (caddr_t) ef->address + es->st_value;
1139 symval->size = es->st_size;
1146 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1147 c_linker_sym_t* sym, long* diffp)
1149 elf_file_t ef = (elf_file_t) lf;
1150 u_long off = (uintptr_t) (void *) value;
1154 const Elf_Sym* best = 0;
1157 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1158 if (es->st_name == 0)
1160 st_value = es->st_value + (uintptr_t) (void *) ef->address;
1161 if (off >= st_value) {
1162 if (off - st_value < diff) {
1163 diff = off - st_value;
1167 } else if (off - st_value == diff) {
1176 *sym = (c_linker_sym_t) best;
1182 * Look up a linker set on an ELF system.
1185 link_elf_lookup_set(linker_file_t lf, const char *name,
1186 void ***startp, void ***stopp, int *countp)
1189 linker_symval_t symval;
1191 void **start, **stop;
1192 int len, error = 0, count;
1194 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
1195 setsym = malloc(len, M_LINKER, M_WAITOK);
1199 /* get address of first entry */
1200 snprintf(setsym, len, "%s%s", "__start_set_", name);
1201 error = link_elf_lookup_symbol(lf, setsym, &sym);
1204 link_elf_symbol_values(lf, sym, &symval);
1205 if (symval.value == 0) {
1209 start = (void **)symval.value;
1211 /* get address of last entry */
1212 snprintf(setsym, len, "%s%s", "__stop_set_", name);
1213 error = link_elf_lookup_symbol(lf, setsym, &sym);
1216 link_elf_symbol_values(lf, sym, &symval);
1217 if (symval.value == 0) {
1221 stop = (void **)symval.value;
1223 /* and the number of entries */
1224 count = stop - start;
1235 free(setsym, M_LINKER);
1240 link_elf_each_function_name(linker_file_t file,
1241 int (*callback)(const char *, void *), void *opaque) {
1242 elf_file_t ef = (elf_file_t)file;
1243 const Elf_Sym* symp;
1246 /* Exhaustive search */
1247 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1248 if (symp->st_value != 0 &&
1249 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1250 error = callback(ef->ddbstrtab + symp->st_name, opaque);
1259 link_elf_each_function_nameval(linker_file_t file,
1260 linker_function_nameval_callback_t callback, void *opaque)
1262 linker_symval_t symval;
1263 elf_file_t ef = (elf_file_t)file;
1264 const Elf_Sym* symp;
1267 /* Exhaustive search */
1268 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1269 if (symp->st_value != 0 &&
1270 ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1271 error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1274 error = callback(file, i, &symval, opaque);
1284 * Each KLD has its own GP. The GP value for each load module is given by
1285 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
1286 * don't have direct access to the ELF file structure. The link_elf_get_gp()
1287 * function returns the GP given a pointer to a generic linker file struct.
1290 link_elf_get_gp(linker_file_t lf)
1292 elf_file_t ef = (elf_file_t)lf;
1293 return (Elf_Addr)ef->got;
1298 elf_get_sym(linker_file_t lf, Elf_Size symidx)
1300 elf_file_t ef = (elf_file_t)lf;
1302 if (symidx >= ef->nchains)
1304 return (ef->symtab + symidx);
1308 elf_get_symname(linker_file_t lf, Elf_Size symidx)
1310 elf_file_t ef = (elf_file_t)lf;
1313 if (symidx >= ef->nchains)
1315 sym = ef->symtab + symidx;
1316 return (ef->strtab + sym->st_name);
1320 * Symbol lookup function that can be used when the symbol index is known (ie
1321 * in relocations). It uses the symbol index instead of doing a fully fledged
1322 * hash table based lookup when such is valid. For example for local symbols.
1323 * This is not only more efficient, it's also more correct. It's not always
1324 * the case that the symbol can be found through the hash table.
1327 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1329 elf_file_t ef = (elf_file_t)lf;
1333 /* Don't even try to lookup the symbol if the index is bogus. */
1334 if (symidx >= ef->nchains)
1337 sym = ef->symtab + symidx;
1340 * Don't do a full lookup when the symbol is local. It may even
1341 * fail because it may not be found through the hash table.
1343 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
1344 /* Force lookup failure when we have an insanity. */
1345 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
1347 return ((Elf_Addr)ef->address + sym->st_value);
1351 * XXX we can avoid doing a hash table based lookup for global
1352 * symbols as well. This however is not always valid, so we'll
1353 * just do it the hard way for now. Performance tweaks can
1357 symbol = ef->strtab + sym->st_name;
1359 /* Force a lookup failure if the symbol name is bogus. */
1363 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1367 link_elf_reloc_local(linker_file_t lf)
1369 const Elf_Rel *rellim;
1371 const Elf_Rela *relalim;
1372 const Elf_Rela *rela;
1373 elf_file_t ef = (elf_file_t)lf;
1375 /* Perform relocations without addend if there are any: */
1376 if ((rel = ef->rel) != NULL) {
1377 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
1378 while (rel < rellim) {
1379 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
1385 /* Perform relocations with addend if there are any: */
1386 if ((rela = ef->rela) != NULL) {
1387 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
1388 while (rela < relalim) {
1389 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,