The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf_obj.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1998-2000 Doug Rabson
    3  * Copyright (c) 2004 Peter Wemm
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  */
   27 
   28 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD: releng/11.0/sys/kern/link_elf_obj.c 298819 2016-04-29 22:15:33Z pfg $");
   30 
   31 #include "opt_ddb.h"
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/kernel.h>
   36 #include <sys/lock.h>
   37 #include <sys/malloc.h>
   38 #include <sys/mutex.h>
   39 #include <sys/mount.h>
   40 #include <sys/proc.h>
   41 #include <sys/namei.h>
   42 #include <sys/fcntl.h>
   43 #include <sys/vnode.h>
   44 #include <sys/linker.h>
   45 
   46 #include <machine/elf.h>
   47 
   48 #include <net/vnet.h>
   49 
   50 #include <security/mac/mac_framework.h>
   51 
   52 #include <vm/vm.h>
   53 #include <vm/vm_param.h>
   54 #include <vm/vm_object.h>
   55 #include <vm/vm_kern.h>
   56 #include <vm/vm_extern.h>
   57 #include <vm/pmap.h>
   58 #include <vm/vm_map.h>
   59 
   60 #include <sys/link_elf.h>
   61 
   62 #ifdef DDB_CTF
   63 #include <sys/zlib.h>
   64 #endif
   65 
   66 #include "linker_if.h"
   67 
   68 typedef struct {
   69         void            *addr;
   70         Elf_Off         size;
   71         int             flags;
   72         int             sec;    /* Original section */
   73         char            *name;
   74 } Elf_progent;
   75 
   76 typedef struct {
   77         Elf_Rel         *rel;
   78         int             nrel;
   79         int             sec;
   80 } Elf_relent;
   81 
   82 typedef struct {
   83         Elf_Rela        *rela;
   84         int             nrela;
   85         int             sec;
   86 } Elf_relaent;
   87 
   88 
   89 typedef struct elf_file {
   90         struct linker_file lf;          /* Common fields */
   91 
   92         int             preloaded;
   93         caddr_t         address;        /* Relocation address */
   94         vm_object_t     object;         /* VM object to hold file pages */
   95         Elf_Shdr        *e_shdr;
   96 
   97         Elf_progent     *progtab;
   98         int             nprogtab;
   99 
  100         Elf_relaent     *relatab;
  101         int             nrelatab;
  102 
  103         Elf_relent      *reltab;
  104         int             nreltab;
  105 
  106         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
  107         long            ddbsymcnt;      /* Number of symbols */
  108         caddr_t         ddbstrtab;      /* String table */
  109         long            ddbstrcnt;      /* number of bytes in string table */
  110 
  111         caddr_t         shstrtab;       /* Section name string table */
  112         long            shstrcnt;       /* number of bytes in string table */
  113 
  114         caddr_t         ctftab;         /* CTF table */
  115         long            ctfcnt;         /* number of bytes in CTF table */
  116         caddr_t         ctfoff;         /* CTF offset table */
  117         caddr_t         typoff;         /* Type offset table */
  118         long            typlen;         /* Number of type entries. */
  119 
  120 } *elf_file_t;
  121 
  122 #include <kern/kern_ctf.c>
  123 
  124 static int      link_elf_link_preload(linker_class_t cls,
  125                     const char *, linker_file_t *);
  126 static int      link_elf_link_preload_finish(linker_file_t);
  127 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
  128 static int      link_elf_lookup_symbol(linker_file_t, const char *,
  129                     c_linker_sym_t *);
  130 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
  131                     linker_symval_t *);
  132 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
  133                     c_linker_sym_t *sym, long *diffp);
  134 
  135 static void     link_elf_unload_file(linker_file_t);
  136 static int      link_elf_lookup_set(linker_file_t, const char *,
  137                     void ***, void ***, int *);
  138 static int      link_elf_each_function_name(linker_file_t,
  139                     int (*)(const char *, void *), void *);
  140 static int      link_elf_each_function_nameval(linker_file_t,
  141                                 linker_function_nameval_callback_t,
  142                                 void *);
  143 static int      link_elf_reloc_local(linker_file_t);
  144 static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
  145 static long     link_elf_strtab_get(linker_file_t, caddr_t *);
  146 
  147 static int      elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
  148                     Elf_Addr *);
  149 
  150 static kobj_method_t link_elf_methods[] = {
  151         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
  152         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
  153         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
  154         KOBJMETHOD(linker_unload,               link_elf_unload_file),
  155         KOBJMETHOD(linker_load_file,            link_elf_load_file),
  156         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
  157         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
  158         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
  159         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
  160         KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
  161         KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
  162         KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
  163         KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
  164         { 0, 0 }
  165 };
  166 
  167 static struct linker_class link_elf_class = {
  168 #if ELF_TARG_CLASS == ELFCLASS32
  169         "elf32_obj",
  170 #else
  171         "elf64_obj",
  172 #endif
  173         link_elf_methods, sizeof(struct elf_file)
  174 };
  175 
  176 static int      relocate_file(elf_file_t ef);
  177 static void     elf_obj_cleanup_globals_cache(elf_file_t);
  178 
  179 static void
  180 link_elf_error(const char *filename, const char *s)
  181 {
  182         if (filename == NULL)
  183                 printf("kldload: %s\n", s);
  184         else
  185                 printf("kldload: %s: %s\n", filename, s);
  186 }
  187 
  188 static void
  189 link_elf_init(void *arg)
  190 {
  191 
  192         linker_add_class(&link_elf_class);
  193 }
  194 
  195 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
  196 
  197 static int
  198 link_elf_link_preload(linker_class_t cls, const char *filename,
  199     linker_file_t *result)
  200 {
  201         Elf_Ehdr *hdr;
  202         Elf_Shdr *shdr;
  203         Elf_Sym *es;
  204         void *modptr, *baseptr, *sizeptr;
  205         char *type;
  206         elf_file_t ef;
  207         linker_file_t lf;
  208         Elf_Addr off;
  209         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
  210 
  211         /* Look to see if we have the file preloaded */
  212         modptr = preload_search_by_name(filename);
  213         if (modptr == NULL)
  214                 return ENOENT;
  215 
  216         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
  217         baseptr = preload_search_info(modptr, MODINFO_ADDR);
  218         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  219         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
  220             MODINFOMD_ELFHDR);
  221         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
  222             MODINFOMD_SHDR);
  223         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
  224             " obj module") != 0 &&
  225             strcmp(type, "elf obj module") != 0)) {
  226                 return (EFTYPE);
  227         }
  228         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
  229             shdr == NULL)
  230                 return (EINVAL);
  231 
  232         lf = linker_make_file(filename, &link_elf_class);
  233         if (lf == NULL)
  234                 return (ENOMEM);
  235 
  236         ef = (elf_file_t)lf;
  237         ef->preloaded = 1;
  238         ef->address = *(caddr_t *)baseptr;
  239         lf->address = *(caddr_t *)baseptr;
  240         lf->size = *(size_t *)sizeptr;
  241 
  242         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
  243             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
  244             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
  245             hdr->e_version != EV_CURRENT ||
  246             hdr->e_type != ET_REL ||
  247             hdr->e_machine != ELF_TARG_MACH) {
  248                 error = EFTYPE;
  249                 goto out;
  250         }
  251         ef->e_shdr = shdr;
  252 
  253         /* Scan the section header for information and table sizing. */
  254         symtabindex = -1;
  255         symstrindex = -1;
  256         for (i = 0; i < hdr->e_shnum; i++) {
  257                 switch (shdr[i].sh_type) {
  258                 case SHT_PROGBITS:
  259                 case SHT_NOBITS:
  260 #ifdef __amd64__
  261                 case SHT_X86_64_UNWIND:
  262 #endif
  263                         ef->nprogtab++;
  264                         break;
  265                 case SHT_SYMTAB:
  266                         symtabindex = i;
  267                         symstrindex = shdr[i].sh_link;
  268                         break;
  269                 case SHT_REL:
  270                         ef->nreltab++;
  271                         break;
  272                 case SHT_RELA:
  273                         ef->nrelatab++;
  274                         break;
  275                 }
  276         }
  277 
  278         shstrindex = hdr->e_shstrndx;
  279         if (ef->nprogtab == 0 || symstrindex < 0 ||
  280             symstrindex >= hdr->e_shnum ||
  281             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
  282             shstrindex >= hdr->e_shnum ||
  283             shdr[shstrindex].sh_type != SHT_STRTAB) {
  284                 printf("%s: bad/missing section headers\n", filename);
  285                 error = ENOEXEC;
  286                 goto out;
  287         }
  288 
  289         /* Allocate space for tracking the load chunks */
  290         if (ef->nprogtab != 0)
  291                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  292                     M_LINKER, M_WAITOK | M_ZERO);
  293         if (ef->nreltab != 0)
  294                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
  295                     M_LINKER, M_WAITOK | M_ZERO);
  296         if (ef->nrelatab != 0)
  297                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
  298                     M_LINKER, M_WAITOK | M_ZERO);
  299         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
  300             (ef->nreltab != 0 && ef->reltab == NULL) ||
  301             (ef->nrelatab != 0 && ef->relatab == NULL)) {
  302                 error = ENOMEM;
  303                 goto out;
  304         }
  305 
  306         /* XXX, relocate the sh_addr fields saved by the loader. */
  307         off = 0;
  308         for (i = 0; i < hdr->e_shnum; i++) {
  309                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
  310                         off = shdr[i].sh_addr;
  311         }
  312         for (i = 0; i < hdr->e_shnum; i++) {
  313                 if (shdr[i].sh_addr != 0)
  314                         shdr[i].sh_addr = shdr[i].sh_addr - off +
  315                             (Elf_Addr)ef->address;
  316         }
  317 
  318         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  319         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
  320         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  321         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
  322         ef->shstrcnt = shdr[shstrindex].sh_size;
  323         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
  324 
  325         /* Now fill out progtab and the relocation tables. */
  326         pb = 0;
  327         rl = 0;
  328         ra = 0;
  329         for (i = 0; i < hdr->e_shnum; i++) {
  330                 switch (shdr[i].sh_type) {
  331                 case SHT_PROGBITS:
  332                 case SHT_NOBITS:
  333 #ifdef __amd64__
  334                 case SHT_X86_64_UNWIND:
  335 #endif
  336                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
  337                         if (shdr[i].sh_type == SHT_PROGBITS)
  338                                 ef->progtab[pb].name = "<<PROGBITS>>";
  339 #ifdef __amd64__
  340                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
  341                                 ef->progtab[pb].name = "<<UNWIND>>";
  342 #endif
  343                         else
  344                                 ef->progtab[pb].name = "<<NOBITS>>";
  345                         ef->progtab[pb].size = shdr[i].sh_size;
  346                         ef->progtab[pb].sec = i;
  347                         if (ef->shstrtab && shdr[i].sh_name != 0)
  348                                 ef->progtab[pb].name =
  349                                     ef->shstrtab + shdr[i].sh_name;
  350                         if (ef->progtab[pb].name != NULL && 
  351                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
  352                                 void *dpcpu;
  353 
  354                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
  355                                 if (dpcpu == NULL) {
  356                                         error = ENOSPC;
  357                                         goto out;
  358                                 }
  359                                 memcpy(dpcpu, ef->progtab[pb].addr,
  360                                     ef->progtab[pb].size);
  361                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
  362                                 ef->progtab[pb].addr = dpcpu;
  363 #ifdef VIMAGE
  364                         } else if (ef->progtab[pb].name != NULL &&
  365                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
  366                                 void *vnet_data;
  367 
  368                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
  369                                 if (vnet_data == NULL) {
  370                                         error = ENOSPC;
  371                                         goto out;
  372                                 }
  373                                 memcpy(vnet_data, ef->progtab[pb].addr,
  374                                     ef->progtab[pb].size);
  375                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
  376                                 ef->progtab[pb].addr = vnet_data;
  377 #endif
  378                         } else if (ef->progtab[pb].name != NULL &&
  379                             !strcmp(ef->progtab[pb].name, ".ctors")) {
  380                                 lf->ctors_addr = ef->progtab[pb].addr;
  381                                 lf->ctors_size = shdr[i].sh_size;
  382                         }
  383 
  384                         /* Update all symbol values with the offset. */
  385                         for (j = 0; j < ef->ddbsymcnt; j++) {
  386                                 es = &ef->ddbsymtab[j];
  387                                 if (es->st_shndx != i)
  388                                         continue;
  389                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  390                         }
  391                         pb++;
  392                         break;
  393                 case SHT_REL:
  394                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
  395                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  396                         ef->reltab[rl].sec = shdr[i].sh_info;
  397                         rl++;
  398                         break;
  399                 case SHT_RELA:
  400                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
  401                         ef->relatab[ra].nrela =
  402                             shdr[i].sh_size / sizeof(Elf_Rela);
  403                         ef->relatab[ra].sec = shdr[i].sh_info;
  404                         ra++;
  405                         break;
  406                 }
  407         }
  408         if (pb != ef->nprogtab) {
  409                 printf("%s: lost progbits\n", filename);
  410                 error = ENOEXEC;
  411                 goto out;
  412         }
  413         if (rl != ef->nreltab) {
  414                 printf("%s: lost reltab\n", filename);
  415                 error = ENOEXEC;
  416                 goto out;
  417         }
  418         if (ra != ef->nrelatab) {
  419                 printf("%s: lost relatab\n", filename);
  420                 error = ENOEXEC;
  421                 goto out;
  422         }
  423 
  424         /* Local intra-module relocations */
  425         error = link_elf_reloc_local(lf);
  426         if (error != 0)
  427                 goto out;
  428 
  429         *result = lf;
  430         return (0);
  431 
  432 out:
  433         /* preload not done this way */
  434         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  435         return (error);
  436 }
  437 
  438 static void
  439 link_elf_invoke_ctors(caddr_t addr, size_t size)
  440 {
  441         void (**ctor)(void);
  442         size_t i, cnt;
  443 
  444         if (addr == NULL || size == 0)
  445                 return;
  446         cnt = size / sizeof(*ctor);
  447         ctor = (void *)addr;
  448         for (i = 0; i < cnt; i++) {
  449                 if (ctor[i] != NULL)
  450                         (*ctor[i])();
  451         }
  452 }
  453 
  454 static int
  455 link_elf_link_preload_finish(linker_file_t lf)
  456 {
  457         elf_file_t ef;
  458         int error;
  459 
  460         ef = (elf_file_t)lf;
  461         error = relocate_file(ef);
  462         if (error)
  463                 return error;
  464 
  465         /* Notify MD code that a module is being loaded. */
  466         error = elf_cpu_load_file(lf);
  467         if (error)
  468                 return (error);
  469 
  470         /* Invoke .ctors */
  471         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
  472         return (0);
  473 }
  474 
  475 static int
  476 link_elf_load_file(linker_class_t cls, const char *filename,
  477     linker_file_t *result)
  478 {
  479         struct nameidata nd;
  480         struct thread *td = curthread;  /* XXX */
  481         Elf_Ehdr *hdr;
  482         Elf_Shdr *shdr;
  483         Elf_Sym *es;
  484         int nbytes, i, j;
  485         vm_offset_t mapbase;
  486         size_t mapsize;
  487         int error = 0;
  488         ssize_t resid;
  489         int flags;
  490         elf_file_t ef;
  491         linker_file_t lf;
  492         int symtabindex;
  493         int symstrindex;
  494         int shstrindex;
  495         int nsym;
  496         int pb, rl, ra;
  497         int alignmask;
  498 
  499         shdr = NULL;
  500         lf = NULL;
  501         mapsize = 0;
  502         hdr = NULL;
  503 
  504         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
  505         flags = FREAD;
  506         error = vn_open(&nd, &flags, 0, NULL);
  507         if (error)
  508                 return error;
  509         NDFREE(&nd, NDF_ONLY_PNBUF);
  510         if (nd.ni_vp->v_type != VREG) {
  511                 error = ENOEXEC;
  512                 goto out;
  513         }
  514 #ifdef MAC
  515         error = mac_kld_check_load(td->td_ucred, nd.ni_vp);
  516         if (error) {
  517                 goto out;
  518         }
  519 #endif
  520 
  521         /* Read the elf header from the file. */
  522         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
  523         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
  524             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  525             &resid, td);
  526         if (error)
  527                 goto out;
  528         if (resid != 0){
  529                 error = ENOEXEC;
  530                 goto out;
  531         }
  532 
  533         if (!IS_ELF(*hdr)) {
  534                 error = ENOEXEC;
  535                 goto out;
  536         }
  537 
  538         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
  539             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
  540                 link_elf_error(filename, "Unsupported file layout");
  541                 error = ENOEXEC;
  542                 goto out;
  543         }
  544         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
  545             || hdr->e_version != EV_CURRENT) {
  546                 link_elf_error(filename, "Unsupported file version");
  547                 error = ENOEXEC;
  548                 goto out;
  549         }
  550         if (hdr->e_type != ET_REL) {
  551                 error = ENOSYS;
  552                 goto out;
  553         }
  554         if (hdr->e_machine != ELF_TARG_MACH) {
  555                 link_elf_error(filename, "Unsupported machine");
  556                 error = ENOEXEC;
  557                 goto out;
  558         }
  559 
  560         lf = linker_make_file(filename, &link_elf_class);
  561         if (!lf) {
  562                 error = ENOMEM;
  563                 goto out;
  564         }
  565         ef = (elf_file_t) lf;
  566         ef->nprogtab = 0;
  567         ef->e_shdr = 0;
  568         ef->nreltab = 0;
  569         ef->nrelatab = 0;
  570 
  571         /* Allocate and read in the section header */
  572         nbytes = hdr->e_shnum * hdr->e_shentsize;
  573         if (nbytes == 0 || hdr->e_shoff == 0 ||
  574             hdr->e_shentsize != sizeof(Elf_Shdr)) {
  575                 error = ENOEXEC;
  576                 goto out;
  577         }
  578         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
  579         ef->e_shdr = shdr;
  580         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
  581             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
  582         if (error)
  583                 goto out;
  584         if (resid) {
  585                 error = ENOEXEC;
  586                 goto out;
  587         }
  588 
  589         /* Scan the section header for information and table sizing. */
  590         nsym = 0;
  591         symtabindex = -1;
  592         symstrindex = -1;
  593         for (i = 0; i < hdr->e_shnum; i++) {
  594                 if (shdr[i].sh_size == 0)
  595                         continue;
  596                 switch (shdr[i].sh_type) {
  597                 case SHT_PROGBITS:
  598                 case SHT_NOBITS:
  599 #ifdef __amd64__
  600                 case SHT_X86_64_UNWIND:
  601 #endif
  602                         ef->nprogtab++;
  603                         break;
  604                 case SHT_SYMTAB:
  605                         nsym++;
  606                         symtabindex = i;
  607                         symstrindex = shdr[i].sh_link;
  608                         break;
  609                 case SHT_REL:
  610                         ef->nreltab++;
  611                         break;
  612                 case SHT_RELA:
  613                         ef->nrelatab++;
  614                         break;
  615                 case SHT_STRTAB:
  616                         break;
  617                 }
  618         }
  619         if (ef->nprogtab == 0) {
  620                 link_elf_error(filename, "file has no contents");
  621                 error = ENOEXEC;
  622                 goto out;
  623         }
  624         if (nsym != 1) {
  625                 /* Only allow one symbol table for now */
  626                 link_elf_error(filename, "file has no valid symbol table");
  627                 error = ENOEXEC;
  628                 goto out;
  629         }
  630         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
  631             shdr[symstrindex].sh_type != SHT_STRTAB) {
  632                 link_elf_error(filename, "file has invalid symbol strings");
  633                 error = ENOEXEC;
  634                 goto out;
  635         }
  636 
  637         /* Allocate space for tracking the load chunks */
  638         if (ef->nprogtab != 0)
  639                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  640                     M_LINKER, M_WAITOK | M_ZERO);
  641         if (ef->nreltab != 0)
  642                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
  643                     M_LINKER, M_WAITOK | M_ZERO);
  644         if (ef->nrelatab != 0)
  645                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
  646                     M_LINKER, M_WAITOK | M_ZERO);
  647 
  648         if (symtabindex == -1) {
  649                 link_elf_error(filename, "lost symbol table index");
  650                 error = ENOEXEC;
  651                 goto out;
  652         }
  653         /* Allocate space for and load the symbol table */
  654         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  655         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
  656         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
  657             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
  658             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  659             &resid, td);
  660         if (error)
  661                 goto out;
  662         if (resid != 0){
  663                 error = EINVAL;
  664                 goto out;
  665         }
  666 
  667         if (symstrindex == -1) {
  668                 link_elf_error(filename, "lost symbol string index");
  669                 error = ENOEXEC;
  670                 goto out;
  671         }
  672         /* Allocate space for and load the symbol strings */
  673         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  674         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
  675         error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
  676             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
  677             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  678             &resid, td);
  679         if (error)
  680                 goto out;
  681         if (resid != 0){
  682                 error = EINVAL;
  683                 goto out;
  684         }
  685 
  686         /* Do we have a string table for the section names?  */
  687         shstrindex = -1;
  688         if (hdr->e_shstrndx != 0 &&
  689             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
  690                 shstrindex = hdr->e_shstrndx;
  691                 ef->shstrcnt = shdr[shstrindex].sh_size;
  692                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
  693                     M_WAITOK);
  694                 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
  695                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
  696                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  697                     &resid, td);
  698                 if (error)
  699                         goto out;
  700                 if (resid != 0){
  701                         error = EINVAL;
  702                         goto out;
  703                 }
  704         }
  705 
  706         /* Size up code/data(progbits) and bss(nobits). */
  707         alignmask = 0;
  708         for (i = 0; i < hdr->e_shnum; i++) {
  709                 if (shdr[i].sh_size == 0)
  710                         continue;
  711                 switch (shdr[i].sh_type) {
  712                 case SHT_PROGBITS:
  713                 case SHT_NOBITS:
  714 #ifdef __amd64__
  715                 case SHT_X86_64_UNWIND:
  716 #endif
  717                         alignmask = shdr[i].sh_addralign - 1;
  718                         mapsize += alignmask;
  719                         mapsize &= ~alignmask;
  720                         mapsize += shdr[i].sh_size;
  721                         break;
  722                 }
  723         }
  724 
  725         /*
  726          * We know how much space we need for the text/data/bss/etc.
  727          * This stuff needs to be in a single chunk so that profiling etc
  728          * can get the bounds and gdb can associate offsets with modules
  729          */
  730         ef->object = vm_object_allocate(OBJT_DEFAULT,
  731             round_page(mapsize) >> PAGE_SHIFT);
  732         if (ef->object == NULL) {
  733                 error = ENOMEM;
  734                 goto out;
  735         }
  736         ef->address = (caddr_t) vm_map_min(kernel_map);
  737 
  738         /*
  739          * In order to satisfy amd64's architectural requirements on the
  740          * location of code and data in the kernel's address space, request a
  741          * mapping that is above the kernel.  
  742          */
  743 #ifdef __amd64__
  744         mapbase = KERNBASE;
  745 #else
  746         mapbase = VM_MIN_KERNEL_ADDRESS;
  747 #endif
  748         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
  749             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
  750             VM_PROT_ALL, 0);
  751         if (error) {
  752                 vm_object_deallocate(ef->object);
  753                 ef->object = 0;
  754                 goto out;
  755         }
  756 
  757         /* Wire the pages */
  758         error = vm_map_wire(kernel_map, mapbase,
  759             mapbase + round_page(mapsize),
  760             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  761         if (error != KERN_SUCCESS) {
  762                 error = ENOMEM;
  763                 goto out;
  764         }
  765 
  766         /* Inform the kld system about the situation */
  767         lf->address = ef->address = (caddr_t)mapbase;
  768         lf->size = mapsize;
  769 
  770         /*
  771          * Now load code/data(progbits), zero bss(nobits), allocate space for
  772          * and load relocs
  773          */
  774         pb = 0;
  775         rl = 0;
  776         ra = 0;
  777         alignmask = 0;
  778         for (i = 0; i < hdr->e_shnum; i++) {
  779                 if (shdr[i].sh_size == 0)
  780                         continue;
  781                 switch (shdr[i].sh_type) {
  782                 case SHT_PROGBITS:
  783                 case SHT_NOBITS:
  784 #ifdef __amd64__
  785                 case SHT_X86_64_UNWIND:
  786 #endif
  787                         alignmask = shdr[i].sh_addralign - 1;
  788                         mapbase += alignmask;
  789                         mapbase &= ~alignmask;
  790                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
  791                                 ef->progtab[pb].name =
  792                                     ef->shstrtab + shdr[i].sh_name;
  793                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
  794                                         lf->ctors_addr = (caddr_t)mapbase;
  795                                         lf->ctors_size = shdr[i].sh_size;
  796                                 }
  797                         } else if (shdr[i].sh_type == SHT_PROGBITS)
  798                                 ef->progtab[pb].name = "<<PROGBITS>>";
  799 #ifdef __amd64__
  800                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
  801                                 ef->progtab[pb].name = "<<UNWIND>>";
  802 #endif
  803                         else
  804                                 ef->progtab[pb].name = "<<NOBITS>>";
  805                         if (ef->progtab[pb].name != NULL && 
  806                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
  807                                 ef->progtab[pb].addr =
  808                                     dpcpu_alloc(shdr[i].sh_size);
  809 #ifdef VIMAGE
  810                         else if (ef->progtab[pb].name != NULL &&
  811                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
  812                                 ef->progtab[pb].addr =
  813                                     vnet_data_alloc(shdr[i].sh_size);
  814 #endif
  815                         else
  816                                 ef->progtab[pb].addr =
  817                                     (void *)(uintptr_t)mapbase;
  818                         if (ef->progtab[pb].addr == NULL) {
  819                                 error = ENOSPC;
  820                                 goto out;
  821                         }
  822                         ef->progtab[pb].size = shdr[i].sh_size;
  823                         ef->progtab[pb].sec = i;
  824                         if (shdr[i].sh_type == SHT_PROGBITS
  825 #ifdef __amd64__
  826                             || shdr[i].sh_type == SHT_X86_64_UNWIND
  827 #endif
  828                             ) {
  829                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
  830                                     ef->progtab[pb].addr,
  831                                     shdr[i].sh_size, shdr[i].sh_offset,
  832                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  833                                     NOCRED, &resid, td);
  834                                 if (error)
  835                                         goto out;
  836                                 if (resid != 0){
  837                                         error = EINVAL;
  838                                         goto out;
  839                                 }
  840                                 /* Initialize the per-cpu or vnet area. */
  841                                 if (ef->progtab[pb].addr != (void *)mapbase &&
  842                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
  843                                         dpcpu_copy(ef->progtab[pb].addr,
  844                                             shdr[i].sh_size);
  845 #ifdef VIMAGE
  846                                 else if (ef->progtab[pb].addr !=
  847                                     (void *)mapbase &&
  848                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
  849                                         vnet_data_copy(ef->progtab[pb].addr,
  850                                             shdr[i].sh_size);
  851 #endif
  852                         } else
  853                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
  854 
  855                         /* Update all symbol values with the offset. */
  856                         for (j = 0; j < ef->ddbsymcnt; j++) {
  857                                 es = &ef->ddbsymtab[j];
  858                                 if (es->st_shndx != i)
  859                                         continue;
  860                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  861                         }
  862                         mapbase += shdr[i].sh_size;
  863                         pb++;
  864                         break;
  865                 case SHT_REL:
  866                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
  867                             M_WAITOK);
  868                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  869                         ef->reltab[rl].sec = shdr[i].sh_info;
  870                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  871                             (void *)ef->reltab[rl].rel,
  872                             shdr[i].sh_size, shdr[i].sh_offset,
  873                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  874                             &resid, td);
  875                         if (error)
  876                                 goto out;
  877                         if (resid != 0){
  878                                 error = EINVAL;
  879                                 goto out;
  880                         }
  881                         rl++;
  882                         break;
  883                 case SHT_RELA:
  884                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
  885                             M_WAITOK);
  886                         ef->relatab[ra].nrela =
  887                             shdr[i].sh_size / sizeof(Elf_Rela);
  888                         ef->relatab[ra].sec = shdr[i].sh_info;
  889                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  890                             (void *)ef->relatab[ra].rela,
  891                             shdr[i].sh_size, shdr[i].sh_offset,
  892                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  893                             &resid, td);
  894                         if (error)
  895                                 goto out;
  896                         if (resid != 0){
  897                                 error = EINVAL;
  898                                 goto out;
  899                         }
  900                         ra++;
  901                         break;
  902                 }
  903         }
  904         if (pb != ef->nprogtab) {
  905                 link_elf_error(filename, "lost progbits");
  906                 error = ENOEXEC;
  907                 goto out;
  908         }
  909         if (rl != ef->nreltab) {
  910                 link_elf_error(filename, "lost reltab");
  911                 error = ENOEXEC;
  912                 goto out;
  913         }
  914         if (ra != ef->nrelatab) {
  915                 link_elf_error(filename, "lost relatab");
  916                 error = ENOEXEC;
  917                 goto out;
  918         }
  919         if (mapbase != (vm_offset_t)ef->address + mapsize) {
  920                 printf(
  921                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
  922                     filename != NULL ? filename : "<none>",
  923                     (u_long)mapbase, ef->address, (u_long)mapsize,
  924                     (u_long)(vm_offset_t)ef->address + mapsize);
  925                 error = ENOMEM;
  926                 goto out;
  927         }
  928 
  929         /* Local intra-module relocations */
  930         error = link_elf_reloc_local(lf);
  931         if (error != 0)
  932                 goto out;
  933 
  934         /* Pull in dependencies */
  935         VOP_UNLOCK(nd.ni_vp, 0);
  936         error = linker_load_dependencies(lf);
  937         vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
  938         if (error)
  939                 goto out;
  940 
  941         /* External relocations */
  942         error = relocate_file(ef);
  943         if (error)
  944                 goto out;
  945 
  946         /* Notify MD code that a module is being loaded. */
  947         error = elf_cpu_load_file(lf);
  948         if (error)
  949                 goto out;
  950 
  951         /* Invoke .ctors */
  952         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
  953 
  954         *result = lf;
  955 
  956 out:
  957         VOP_UNLOCK(nd.ni_vp, 0);
  958         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  959         if (error && lf)
  960                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  961         free(hdr, M_LINKER);
  962 
  963         return error;
  964 }
  965 
  966 static void
  967 link_elf_unload_file(linker_file_t file)
  968 {
  969         elf_file_t ef = (elf_file_t) file;
  970         int i;
  971 
  972         /* Notify MD code that a module is being unloaded. */
  973         elf_cpu_unload_file(file);
  974 
  975         if (ef->progtab) {
  976                 for (i = 0; i < ef->nprogtab; i++) {
  977                         if (ef->progtab[i].size == 0)
  978                                 continue;
  979                         if (ef->progtab[i].name == NULL)
  980                                 continue;
  981                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
  982                                 dpcpu_free(ef->progtab[i].addr,
  983                                     ef->progtab[i].size);
  984 #ifdef VIMAGE
  985                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
  986                                 vnet_data_free(ef->progtab[i].addr,
  987                                     ef->progtab[i].size);
  988 #endif
  989                 }
  990         }
  991         if (ef->preloaded) {
  992                 free(ef->reltab, M_LINKER);
  993                 free(ef->relatab, M_LINKER);
  994                 free(ef->progtab, M_LINKER);
  995                 free(ef->ctftab, M_LINKER);
  996                 free(ef->ctfoff, M_LINKER);
  997                 free(ef->typoff, M_LINKER);
  998                 if (file->filename != NULL)
  999                         preload_delete_name(file->filename);
 1000                 /* XXX reclaim module memory? */
 1001                 return;
 1002         }
 1003 
 1004         for (i = 0; i < ef->nreltab; i++)
 1005                 free(ef->reltab[i].rel, M_LINKER);
 1006         for (i = 0; i < ef->nrelatab; i++)
 1007                 free(ef->relatab[i].rela, M_LINKER);
 1008         free(ef->reltab, M_LINKER);
 1009         free(ef->relatab, M_LINKER);
 1010         free(ef->progtab, M_LINKER);
 1011 
 1012         if (ef->object) {
 1013                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
 1014                     (vm_offset_t) ef->address +
 1015                     (ef->object->size << PAGE_SHIFT));
 1016         }
 1017         free(ef->e_shdr, M_LINKER);
 1018         free(ef->ddbsymtab, M_LINKER);
 1019         free(ef->ddbstrtab, M_LINKER);
 1020         free(ef->shstrtab, M_LINKER);
 1021         free(ef->ctftab, M_LINKER);
 1022         free(ef->ctfoff, M_LINKER);
 1023         free(ef->typoff, M_LINKER);
 1024 }
 1025 
 1026 static const char *
 1027 symbol_name(elf_file_t ef, Elf_Size r_info)
 1028 {
 1029         const Elf_Sym *ref;
 1030 
 1031         if (ELF_R_SYM(r_info)) {
 1032                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
 1033                 return ef->ddbstrtab + ref->st_name;
 1034         } else
 1035                 return NULL;
 1036 }
 1037 
 1038 static Elf_Addr
 1039 findbase(elf_file_t ef, int sec)
 1040 {
 1041         int i;
 1042         Elf_Addr base = 0;
 1043 
 1044         for (i = 0; i < ef->nprogtab; i++) {
 1045                 if (sec == ef->progtab[i].sec) {
 1046                         base = (Elf_Addr)ef->progtab[i].addr;
 1047                         break;
 1048                 }
 1049         }
 1050         return base;
 1051 }
 1052 
 1053 static int
 1054 relocate_file(elf_file_t ef)
 1055 {
 1056         const Elf_Rel *rellim;
 1057         const Elf_Rel *rel;
 1058         const Elf_Rela *relalim;
 1059         const Elf_Rela *rela;
 1060         const char *symname;
 1061         const Elf_Sym *sym;
 1062         int i;
 1063         Elf_Size symidx;
 1064         Elf_Addr base;
 1065 
 1066 
 1067         /* Perform relocations without addend if there are any: */
 1068         for (i = 0; i < ef->nreltab; i++) {
 1069                 rel = ef->reltab[i].rel;
 1070                 if (rel == NULL) {
 1071                         link_elf_error(ef->lf.filename, "lost a reltab!");
 1072                         return (ENOEXEC);
 1073                 }
 1074                 rellim = rel + ef->reltab[i].nrel;
 1075                 base = findbase(ef, ef->reltab[i].sec);
 1076                 if (base == 0) {
 1077                         link_elf_error(ef->lf.filename, "lost base for reltab");
 1078                         return (ENOEXEC);
 1079                 }
 1080                 for ( ; rel < rellim; rel++) {
 1081                         symidx = ELF_R_SYM(rel->r_info);
 1082                         if (symidx >= ef->ddbsymcnt)
 1083                                 continue;
 1084                         sym = ef->ddbsymtab + symidx;
 1085                         /* Local relocs are already done */
 1086                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 1087                                 continue;
 1088                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
 1089                             elf_obj_lookup)) {
 1090                                 symname = symbol_name(ef, rel->r_info);
 1091                                 printf("link_elf_obj: symbol %s undefined\n",
 1092                                     symname);
 1093                                 return (ENOENT);
 1094                         }
 1095                 }
 1096         }
 1097 
 1098         /* Perform relocations with addend if there are any: */
 1099         for (i = 0; i < ef->nrelatab; i++) {
 1100                 rela = ef->relatab[i].rela;
 1101                 if (rela == NULL) {
 1102                         link_elf_error(ef->lf.filename, "lost a relatab!");
 1103                         return (ENOEXEC);
 1104                 }
 1105                 relalim = rela + ef->relatab[i].nrela;
 1106                 base = findbase(ef, ef->relatab[i].sec);
 1107                 if (base == 0) {
 1108                         link_elf_error(ef->lf.filename,
 1109                             "lost base for relatab");
 1110                         return (ENOEXEC);
 1111                 }
 1112                 for ( ; rela < relalim; rela++) {
 1113                         symidx = ELF_R_SYM(rela->r_info);
 1114                         if (symidx >= ef->ddbsymcnt)
 1115                                 continue;
 1116                         sym = ef->ddbsymtab + symidx;
 1117                         /* Local relocs are already done */
 1118                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 1119                                 continue;
 1120                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
 1121                             elf_obj_lookup)) {
 1122                                 symname = symbol_name(ef, rela->r_info);
 1123                                 printf("link_elf_obj: symbol %s undefined\n",
 1124                                     symname);
 1125                                 return (ENOENT);
 1126                         }
 1127                 }
 1128         }
 1129 
 1130         /*
 1131          * Only clean SHN_FBSD_CACHED for successful return.  If we
 1132          * modified symbol table for the object but found an
 1133          * unresolved symbol, there is no reason to roll back.
 1134          */
 1135         elf_obj_cleanup_globals_cache(ef);
 1136 
 1137         return (0);
 1138 }
 1139 
 1140 static int
 1141 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
 1142 {
 1143         elf_file_t ef = (elf_file_t) lf;
 1144         const Elf_Sym *symp;
 1145         const char *strp;
 1146         int i;
 1147 
 1148         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1149                 strp = ef->ddbstrtab + symp->st_name;
 1150                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
 1151                         *sym = (c_linker_sym_t) symp;
 1152                         return 0;
 1153                 }
 1154         }
 1155         return ENOENT;
 1156 }
 1157 
 1158 static int
 1159 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
 1160     linker_symval_t *symval)
 1161 {
 1162         elf_file_t ef = (elf_file_t) lf;
 1163         const Elf_Sym *es = (const Elf_Sym*) sym;
 1164 
 1165         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 1166                 symval->name = ef->ddbstrtab + es->st_name;
 1167                 symval->value = (caddr_t)es->st_value;
 1168                 symval->size = es->st_size;
 1169                 return 0;
 1170         }
 1171         return ENOENT;
 1172 }
 1173 
 1174 static int
 1175 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 1176     c_linker_sym_t *sym, long *diffp)
 1177 {
 1178         elf_file_t ef = (elf_file_t) lf;
 1179         u_long off = (uintptr_t) (void *) value;
 1180         u_long diff = off;
 1181         u_long st_value;
 1182         const Elf_Sym *es;
 1183         const Elf_Sym *best = NULL;
 1184         int i;
 1185 
 1186         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 1187                 if (es->st_name == 0)
 1188                         continue;
 1189                 st_value = es->st_value;
 1190                 if (off >= st_value) {
 1191                         if (off - st_value < diff) {
 1192                                 diff = off - st_value;
 1193                                 best = es;
 1194                                 if (diff == 0)
 1195                                         break;
 1196                         } else if (off - st_value == diff) {
 1197                                 best = es;
 1198                         }
 1199                 }
 1200         }
 1201         if (best == NULL)
 1202                 *diffp = off;
 1203         else
 1204                 *diffp = diff;
 1205         *sym = (c_linker_sym_t) best;
 1206 
 1207         return 0;
 1208 }
 1209 
 1210 /*
 1211  * Look up a linker set on an ELF system.
 1212  */
 1213 static int
 1214 link_elf_lookup_set(linker_file_t lf, const char *name,
 1215     void ***startp, void ***stopp, int *countp)
 1216 {
 1217         elf_file_t ef = (elf_file_t)lf;
 1218         void **start, **stop;
 1219         int i, count;
 1220 
 1221         /* Relative to section number */
 1222         for (i = 0; i < ef->nprogtab; i++) {
 1223                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
 1224                     strcmp(ef->progtab[i].name + 4, name) == 0) {
 1225                         start  = (void **)ef->progtab[i].addr;
 1226                         stop = (void **)((char *)ef->progtab[i].addr +
 1227                             ef->progtab[i].size);
 1228                         count = stop - start;
 1229                         if (startp)
 1230                                 *startp = start;
 1231                         if (stopp)
 1232                                 *stopp = stop;
 1233                         if (countp)
 1234                                 *countp = count;
 1235                         return (0);
 1236                 }
 1237         }
 1238         return (ESRCH);
 1239 }
 1240 
 1241 static int
 1242 link_elf_each_function_name(linker_file_t file,
 1243     int (*callback)(const char *, void *), void *opaque)
 1244 {
 1245         elf_file_t ef = (elf_file_t)file;
 1246         const Elf_Sym *symp;
 1247         int i, error;
 1248         
 1249         /* Exhaustive search */
 1250         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1251                 if (symp->st_value != 0 &&
 1252                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1253                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
 1254                         if (error)
 1255                                 return (error);
 1256                 }
 1257         }
 1258         return (0);
 1259 }
 1260 
 1261 static int
 1262 link_elf_each_function_nameval(linker_file_t file,
 1263     linker_function_nameval_callback_t callback, void *opaque)
 1264 {
 1265         linker_symval_t symval;
 1266         elf_file_t ef = (elf_file_t)file;
 1267         const Elf_Sym* symp;
 1268         int i, error;
 1269 
 1270         /* Exhaustive search */
 1271         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1272                 if (symp->st_value != 0 &&
 1273                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1274                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
 1275                         if (error)
 1276                                 return (error);
 1277                         error = callback(file, i, &symval, opaque);
 1278                         if (error)
 1279                                 return (error);
 1280                 }
 1281         }
 1282         return (0);
 1283 }
 1284 
 1285 static void
 1286 elf_obj_cleanup_globals_cache(elf_file_t ef)
 1287 {
 1288         Elf_Sym *sym;
 1289         Elf_Size i;
 1290 
 1291         for (i = 0; i < ef->ddbsymcnt; i++) {
 1292                 sym = ef->ddbsymtab + i;
 1293                 if (sym->st_shndx == SHN_FBSD_CACHED) {
 1294                         sym->st_shndx = SHN_UNDEF;
 1295                         sym->st_value = 0;
 1296                 }
 1297         }
 1298 }
 1299 
 1300 /*
 1301  * Symbol lookup function that can be used when the symbol index is known (ie
 1302  * in relocations). It uses the symbol index instead of doing a fully fledged
 1303  * hash table based lookup when such is valid. For example for local symbols.
 1304  * This is not only more efficient, it's also more correct. It's not always
 1305  * the case that the symbol can be found through the hash table.
 1306  */
 1307 static int
 1308 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
 1309 {
 1310         elf_file_t ef = (elf_file_t)lf;
 1311         Elf_Sym *sym;
 1312         const char *symbol;
 1313         Elf_Addr res1;
 1314 
 1315         /* Don't even try to lookup the symbol if the index is bogus. */
 1316         if (symidx >= ef->ddbsymcnt) {
 1317                 *res = 0;
 1318                 return (EINVAL);
 1319         }
 1320 
 1321         sym = ef->ddbsymtab + symidx;
 1322 
 1323         /* Quick answer if there is a definition included. */
 1324         if (sym->st_shndx != SHN_UNDEF) {
 1325                 *res = sym->st_value;
 1326                 return (0);
 1327         }
 1328 
 1329         /* If we get here, then it is undefined and needs a lookup. */
 1330         switch (ELF_ST_BIND(sym->st_info)) {
 1331         case STB_LOCAL:
 1332                 /* Local, but undefined? huh? */
 1333                 *res = 0;
 1334                 return (EINVAL);
 1335 
 1336         case STB_GLOBAL:
 1337         case STB_WEAK:
 1338                 /* Relative to Data or Function name */
 1339                 symbol = ef->ddbstrtab + sym->st_name;
 1340 
 1341                 /* Force a lookup failure if the symbol name is bogus. */
 1342                 if (*symbol == 0) {
 1343                         *res = 0;
 1344                         return (EINVAL);
 1345                 }
 1346                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
 1347 
 1348                 /*
 1349                  * Cache global lookups during module relocation. The failure
 1350                  * case is particularly expensive for callers, who must scan
 1351                  * through the entire globals table doing strcmp(). Cache to
 1352                  * avoid doing such work repeatedly.
 1353                  *
 1354                  * After relocation is complete, undefined globals will be
 1355                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
 1356                  * above.
 1357                  */
 1358                 if (res1 != 0) {
 1359                         sym->st_shndx = SHN_FBSD_CACHED;
 1360                         sym->st_value = res1;
 1361                         *res = res1;
 1362                         return (0);
 1363                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
 1364                         sym->st_value = 0;
 1365                         *res = 0;
 1366                         return (0);
 1367                 }
 1368                 return (EINVAL);
 1369 
 1370         default:
 1371                 return (EINVAL);
 1372         }
 1373 }
 1374 
 1375 static void
 1376 link_elf_fix_link_set(elf_file_t ef)
 1377 {
 1378         static const char startn[] = "__start_";
 1379         static const char stopn[] = "__stop_";
 1380         Elf_Sym *sym;
 1381         const char *sym_name, *linkset_name;
 1382         Elf_Addr startp, stopp;
 1383         Elf_Size symidx;
 1384         int start, i;
 1385 
 1386         startp = stopp = 0;
 1387         for (symidx = 1 /* zero entry is special */;
 1388                 symidx < ef->ddbsymcnt; symidx++) {
 1389                 sym = ef->ddbsymtab + symidx;
 1390                 if (sym->st_shndx != SHN_UNDEF)
 1391                         continue;
 1392 
 1393                 sym_name = ef->ddbstrtab + sym->st_name;
 1394                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
 1395                         start = 1;
 1396                         linkset_name = sym_name + sizeof(startn) - 1;
 1397                 }
 1398                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
 1399                         start = 0;
 1400                         linkset_name = sym_name + sizeof(stopn) - 1;
 1401                 }
 1402                 else
 1403                         continue;
 1404 
 1405                 for (i = 0; i < ef->nprogtab; i++) {
 1406                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
 1407                                 startp = (Elf_Addr)ef->progtab[i].addr;
 1408                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
 1409                                 break;
 1410                         }
 1411                 }
 1412                 if (i == ef->nprogtab)
 1413                         continue;
 1414 
 1415                 sym->st_value = start ? startp : stopp;
 1416                 sym->st_shndx = i;
 1417         }
 1418 }
 1419 
 1420 static int
 1421 link_elf_reloc_local(linker_file_t lf)
 1422 {
 1423         elf_file_t ef = (elf_file_t)lf;
 1424         const Elf_Rel *rellim;
 1425         const Elf_Rel *rel;
 1426         const Elf_Rela *relalim;
 1427         const Elf_Rela *rela;
 1428         const Elf_Sym *sym;
 1429         Elf_Addr base;
 1430         int i;
 1431         Elf_Size symidx;
 1432 
 1433         link_elf_fix_link_set(ef);
 1434 
 1435         /* Perform relocations without addend if there are any: */
 1436         for (i = 0; i < ef->nreltab; i++) {
 1437                 rel = ef->reltab[i].rel;
 1438                 if (rel == NULL) {
 1439                         link_elf_error(ef->lf.filename, "lost a reltab");
 1440                         return (ENOEXEC);
 1441                 }
 1442                 rellim = rel + ef->reltab[i].nrel;
 1443                 base = findbase(ef, ef->reltab[i].sec);
 1444                 if (base == 0) {
 1445                         link_elf_error(ef->lf.filename, "lost base for reltab");
 1446                         return (ENOEXEC);
 1447                 }
 1448                 for ( ; rel < rellim; rel++) {
 1449                         symidx = ELF_R_SYM(rel->r_info);
 1450                         if (symidx >= ef->ddbsymcnt)
 1451                                 continue;
 1452                         sym = ef->ddbsymtab + symidx;
 1453                         /* Only do local relocs */
 1454                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1455                                 continue;
 1456                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
 1457                             elf_obj_lookup);
 1458                 }
 1459         }
 1460 
 1461         /* Perform relocations with addend if there are any: */
 1462         for (i = 0; i < ef->nrelatab; i++) {
 1463                 rela = ef->relatab[i].rela;
 1464                 if (rela == NULL) {
 1465                         link_elf_error(ef->lf.filename, "lost a relatab!");
 1466                         return (ENOEXEC);
 1467                 }
 1468                 relalim = rela + ef->relatab[i].nrela;
 1469                 base = findbase(ef, ef->relatab[i].sec);
 1470                 if (base == 0) {
 1471                         link_elf_error(ef->lf.filename, "lost base for reltab");
 1472                         return (ENOEXEC);
 1473                 }
 1474                 for ( ; rela < relalim; rela++) {
 1475                         symidx = ELF_R_SYM(rela->r_info);
 1476                         if (symidx >= ef->ddbsymcnt)
 1477                                 continue;
 1478                         sym = ef->ddbsymtab + symidx;
 1479                         /* Only do local relocs */
 1480                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1481                                 continue;
 1482                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
 1483                             elf_obj_lookup);
 1484                 }
 1485         }
 1486         return (0);
 1487 }
 1488 
 1489 static long
 1490 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
 1491 {
 1492     elf_file_t ef = (elf_file_t)lf;
 1493     
 1494     *symtab = ef->ddbsymtab;
 1495     
 1496     if (*symtab == NULL)
 1497         return (0);
 1498 
 1499     return (ef->ddbsymcnt);
 1500 }
 1501     
 1502 static long
 1503 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
 1504 {
 1505     elf_file_t ef = (elf_file_t)lf;
 1506 
 1507     *strtab = ef->ddbstrtab;
 1508 
 1509     if (*strtab == NULL)
 1510         return (0);
 1511 
 1512     return (ef->ddbstrcnt);
 1513 }

Cache object: 1f01c21ef7acaaf894035beaf82b394a


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.