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


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

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    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/9.0/sys/kern/link_elf_obj.c 220730 2011-04-16 16:20:51Z dchagin $");
   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 <net/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 void     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 Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps);
  148 
  149 static kobj_method_t link_elf_methods[] = {
  150         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
  151         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
  152         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
  153         KOBJMETHOD(linker_unload,               link_elf_unload_file),
  154         KOBJMETHOD(linker_load_file,            link_elf_load_file),
  155         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
  156         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
  157         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
  158         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
  159         KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
  160         KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
  161         KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
  162         KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
  163         { 0, 0 }
  164 };
  165 
  166 static struct linker_class link_elf_class = {
  167 #if ELF_TARG_CLASS == ELFCLASS32
  168         "elf32_obj",
  169 #else
  170         "elf64_obj",
  171 #endif
  172         link_elf_methods, sizeof(struct elf_file)
  173 };
  174 
  175 static int      relocate_file(elf_file_t ef);
  176 
  177 static void
  178 link_elf_error(const char *filename, const char *s)
  179 {
  180         if (filename == NULL)
  181                 printf("kldload: %s\n", s);
  182         else
  183                 printf("kldload: %s: %s\n", filename, s);
  184 }
  185 
  186 static void
  187 link_elf_init(void *arg)
  188 {
  189 
  190         linker_add_class(&link_elf_class);
  191 }
  192 
  193 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
  194 
  195 static int
  196 link_elf_link_preload(linker_class_t cls, const char *filename,
  197     linker_file_t *result)
  198 {
  199         Elf_Ehdr *hdr;
  200         Elf_Shdr *shdr;
  201         Elf_Sym *es;
  202         void *modptr, *baseptr, *sizeptr;
  203         char *type;
  204         elf_file_t ef;
  205         linker_file_t lf;
  206         Elf_Addr off;
  207         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
  208 
  209         /* Look to see if we have the file preloaded */
  210         modptr = preload_search_by_name(filename);
  211         if (modptr == NULL)
  212                 return ENOENT;
  213 
  214         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
  215         baseptr = preload_search_info(modptr, MODINFO_ADDR);
  216         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  217         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
  218             MODINFOMD_ELFHDR);
  219         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
  220             MODINFOMD_SHDR);
  221         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
  222             " obj module") != 0 &&
  223             strcmp(type, "elf obj module") != 0)) {
  224                 return (EFTYPE);
  225         }
  226         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
  227             shdr == NULL)
  228                 return (EINVAL);
  229 
  230         lf = linker_make_file(filename, &link_elf_class);
  231         if (lf == NULL)
  232                 return (ENOMEM);
  233 
  234         ef = (elf_file_t)lf;
  235         ef->preloaded = 1;
  236         ef->address = *(caddr_t *)baseptr;
  237         lf->address = *(caddr_t *)baseptr;
  238         lf->size = *(size_t *)sizeptr;
  239 
  240         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
  241             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
  242             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
  243             hdr->e_version != EV_CURRENT ||
  244             hdr->e_type != ET_REL ||
  245             hdr->e_machine != ELF_TARG_MACH) {
  246                 error = EFTYPE;
  247                 goto out;
  248         }
  249         ef->e_shdr = shdr;
  250 
  251         /* Scan the section header for information and table sizing. */
  252         symtabindex = -1;
  253         symstrindex = -1;
  254         for (i = 0; i < hdr->e_shnum; i++) {
  255                 switch (shdr[i].sh_type) {
  256                 case SHT_PROGBITS:
  257                 case SHT_NOBITS:
  258                         ef->nprogtab++;
  259                         break;
  260                 case SHT_SYMTAB:
  261                         symtabindex = i;
  262                         symstrindex = shdr[i].sh_link;
  263                         break;
  264                 case SHT_REL:
  265                         ef->nreltab++;
  266                         break;
  267                 case SHT_RELA:
  268                         ef->nrelatab++;
  269                         break;
  270                 }
  271         }
  272 
  273         shstrindex = hdr->e_shstrndx;
  274         if (ef->nprogtab == 0 || symstrindex < 0 ||
  275             symstrindex >= hdr->e_shnum ||
  276             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
  277             shstrindex >= hdr->e_shnum ||
  278             shdr[shstrindex].sh_type != SHT_STRTAB) {
  279                 printf("%s: bad/missing section headers\n", filename);
  280                 error = ENOEXEC;
  281                 goto out;
  282         }
  283 
  284         /* Allocate space for tracking the load chunks */
  285         if (ef->nprogtab != 0)
  286                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  287                     M_LINKER, M_WAITOK | M_ZERO);
  288         if (ef->nreltab != 0)
  289                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
  290                     M_LINKER, M_WAITOK | M_ZERO);
  291         if (ef->nrelatab != 0)
  292                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
  293                     M_LINKER, M_WAITOK | M_ZERO);
  294         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
  295             (ef->nreltab != 0 && ef->reltab == NULL) ||
  296             (ef->nrelatab != 0 && ef->relatab == NULL)) {
  297                 error = ENOMEM;
  298                 goto out;
  299         }
  300 
  301         /* XXX, relocate the sh_addr fields saved by the loader. */
  302         off = 0;
  303         for (i = 0; i < hdr->e_shnum; i++) {
  304                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
  305                         off = shdr[i].sh_addr;
  306         }
  307         for (i = 0; i < hdr->e_shnum; i++) {
  308                 if (shdr[i].sh_addr != 0)
  309                         shdr[i].sh_addr = shdr[i].sh_addr - off +
  310                             (Elf_Addr)ef->address;
  311         }
  312 
  313         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  314         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
  315         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  316         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
  317         ef->shstrcnt = shdr[shstrindex].sh_size;
  318         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
  319 
  320         /* Now fill out progtab and the relocation tables. */
  321         pb = 0;
  322         rl = 0;
  323         ra = 0;
  324         for (i = 0; i < hdr->e_shnum; i++) {
  325                 switch (shdr[i].sh_type) {
  326                 case SHT_PROGBITS:
  327                 case SHT_NOBITS:
  328                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
  329                         if (shdr[i].sh_type == SHT_PROGBITS)
  330                                 ef->progtab[pb].name = "<<PROGBITS>>";
  331                         else
  332                                 ef->progtab[pb].name = "<<NOBITS>>";
  333                         ef->progtab[pb].size = shdr[i].sh_size;
  334                         ef->progtab[pb].sec = i;
  335                         if (ef->shstrtab && shdr[i].sh_name != 0)
  336                                 ef->progtab[pb].name =
  337                                     ef->shstrtab + shdr[i].sh_name;
  338                         if (ef->progtab[pb].name != NULL && 
  339                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
  340                                 void *dpcpu;
  341 
  342                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
  343                                 if (dpcpu == NULL) {
  344                                         error = ENOSPC;
  345                                         goto out;
  346                                 }
  347                                 memcpy(dpcpu, ef->progtab[pb].addr,
  348                                     ef->progtab[pb].size);
  349                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
  350                                 ef->progtab[pb].addr = dpcpu;
  351 #ifdef VIMAGE
  352                         } else if (ef->progtab[pb].name != NULL &&
  353                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
  354                                 void *vnet_data;
  355 
  356                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
  357                                 if (vnet_data == NULL) {
  358                                         error = ENOSPC;
  359                                         goto out;
  360                                 }
  361                                 memcpy(vnet_data, ef->progtab[pb].addr,
  362                                     ef->progtab[pb].size);
  363                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
  364                                 ef->progtab[pb].addr = vnet_data;
  365 #endif
  366                         }
  367 
  368                         /* Update all symbol values with the offset. */
  369                         for (j = 0; j < ef->ddbsymcnt; j++) {
  370                                 es = &ef->ddbsymtab[j];
  371                                 if (es->st_shndx != i)
  372                                         continue;
  373                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  374                         }
  375                         pb++;
  376                         break;
  377                 case SHT_REL:
  378                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
  379                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  380                         ef->reltab[rl].sec = shdr[i].sh_info;
  381                         rl++;
  382                         break;
  383                 case SHT_RELA:
  384                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
  385                         ef->relatab[ra].nrela =
  386                             shdr[i].sh_size / sizeof(Elf_Rela);
  387                         ef->relatab[ra].sec = shdr[i].sh_info;
  388                         ra++;
  389                         break;
  390                 }
  391         }
  392         if (pb != ef->nprogtab)
  393                 panic("lost progbits");
  394         if (rl != ef->nreltab)
  395                 panic("lost reltab");
  396         if (ra != ef->nrelatab)
  397                 panic("lost relatab");
  398 
  399         /* Local intra-module relocations */
  400         link_elf_reloc_local(lf);
  401 
  402         *result = lf;
  403         return (0);
  404 
  405 out:
  406         /* preload not done this way */
  407         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  408         return (error);
  409 }
  410 
  411 static int
  412 link_elf_link_preload_finish(linker_file_t lf)
  413 {
  414         elf_file_t ef;
  415         int error;
  416 
  417         ef = (elf_file_t)lf;
  418         error = relocate_file(ef);
  419         if (error)
  420                 return error;
  421 
  422         /* Notify MD code that a module is being loaded. */
  423         error = elf_cpu_load_file(lf);
  424         if (error)
  425                 return (error);
  426 
  427         return (0);
  428 }
  429 
  430 static int
  431 link_elf_load_file(linker_class_t cls, const char *filename,
  432     linker_file_t *result)
  433 {
  434         struct nameidata nd;
  435         struct thread *td = curthread;  /* XXX */
  436         Elf_Ehdr *hdr;
  437         Elf_Shdr *shdr;
  438         Elf_Sym *es;
  439         int nbytes, i, j;
  440         vm_offset_t mapbase;
  441         size_t mapsize;
  442         int error = 0;
  443         int resid, flags;
  444         elf_file_t ef;
  445         linker_file_t lf;
  446         int symtabindex;
  447         int symstrindex;
  448         int shstrindex;
  449         int nsym;
  450         int pb, rl, ra;
  451         int alignmask;
  452         int vfslocked;
  453 
  454         shdr = NULL;
  455         lf = NULL;
  456         mapsize = 0;
  457         hdr = NULL;
  458 
  459         NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
  460         flags = FREAD;
  461         error = vn_open(&nd, &flags, 0, NULL);
  462         if (error)
  463                 return error;
  464         vfslocked = NDHASGIANT(&nd);
  465         NDFREE(&nd, NDF_ONLY_PNBUF);
  466         if (nd.ni_vp->v_type != VREG) {
  467                 error = ENOEXEC;
  468                 goto out;
  469         }
  470 #ifdef MAC
  471         error = mac_kld_check_load(td->td_ucred, nd.ni_vp);
  472         if (error) {
  473                 goto out;
  474         }
  475 #endif
  476 
  477         /* Read the elf header from the file. */
  478         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
  479         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
  480             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  481             &resid, td);
  482         if (error)
  483                 goto out;
  484         if (resid != 0){
  485                 error = ENOEXEC;
  486                 goto out;
  487         }
  488 
  489         if (!IS_ELF(*hdr)) {
  490                 error = ENOEXEC;
  491                 goto out;
  492         }
  493 
  494         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
  495             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
  496                 link_elf_error(filename, "Unsupported file layout");
  497                 error = ENOEXEC;
  498                 goto out;
  499         }
  500         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
  501             || hdr->e_version != EV_CURRENT) {
  502                 link_elf_error(filename, "Unsupported file version");
  503                 error = ENOEXEC;
  504                 goto out;
  505         }
  506         if (hdr->e_type != ET_REL) {
  507                 error = ENOSYS;
  508                 goto out;
  509         }
  510         if (hdr->e_machine != ELF_TARG_MACH) {
  511                 link_elf_error(filename, "Unsupported machine");
  512                 error = ENOEXEC;
  513                 goto out;
  514         }
  515 
  516         lf = linker_make_file(filename, &link_elf_class);
  517         if (!lf) {
  518                 error = ENOMEM;
  519                 goto out;
  520         }
  521         ef = (elf_file_t) lf;
  522         ef->nprogtab = 0;
  523         ef->e_shdr = 0;
  524         ef->nreltab = 0;
  525         ef->nrelatab = 0;
  526 
  527         /* Allocate and read in the section header */
  528         nbytes = hdr->e_shnum * hdr->e_shentsize;
  529         if (nbytes == 0 || hdr->e_shoff == 0 ||
  530             hdr->e_shentsize != sizeof(Elf_Shdr)) {
  531                 error = ENOEXEC;
  532                 goto out;
  533         }
  534         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
  535         ef->e_shdr = shdr;
  536         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
  537             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
  538         if (error)
  539                 goto out;
  540         if (resid) {
  541                 error = ENOEXEC;
  542                 goto out;
  543         }
  544 
  545         /* Scan the section header for information and table sizing. */
  546         nsym = 0;
  547         symtabindex = -1;
  548         symstrindex = -1;
  549         for (i = 0; i < hdr->e_shnum; i++) {
  550                 if (shdr[i].sh_size == 0)
  551                         continue;
  552                 switch (shdr[i].sh_type) {
  553                 case SHT_PROGBITS:
  554                 case SHT_NOBITS:
  555                         ef->nprogtab++;
  556                         break;
  557                 case SHT_SYMTAB:
  558                         nsym++;
  559                         symtabindex = i;
  560                         symstrindex = shdr[i].sh_link;
  561                         break;
  562                 case SHT_REL:
  563                         ef->nreltab++;
  564                         break;
  565                 case SHT_RELA:
  566                         ef->nrelatab++;
  567                         break;
  568                 case SHT_STRTAB:
  569                         break;
  570                 }
  571         }
  572         if (ef->nprogtab == 0) {
  573                 link_elf_error(filename, "file has no contents");
  574                 error = ENOEXEC;
  575                 goto out;
  576         }
  577         if (nsym != 1) {
  578                 /* Only allow one symbol table for now */
  579                 link_elf_error(filename, "file has no valid symbol table");
  580                 error = ENOEXEC;
  581                 goto out;
  582         }
  583         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
  584             shdr[symstrindex].sh_type != SHT_STRTAB) {
  585                 link_elf_error(filename, "file has invalid symbol strings");
  586                 error = ENOEXEC;
  587                 goto out;
  588         }
  589 
  590         /* Allocate space for tracking the load chunks */
  591         if (ef->nprogtab != 0)
  592                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  593                     M_LINKER, M_WAITOK | M_ZERO);
  594         if (ef->nreltab != 0)
  595                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
  596                     M_LINKER, M_WAITOK | M_ZERO);
  597         if (ef->nrelatab != 0)
  598                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
  599                     M_LINKER, M_WAITOK | M_ZERO);
  600 
  601         if (symtabindex == -1)
  602                 panic("lost symbol table index");
  603         /* Allocate space for and load the symbol table */
  604         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  605         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
  606         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
  607             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
  608             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  609             &resid, td);
  610         if (error)
  611                 goto out;
  612         if (resid != 0){
  613                 error = EINVAL;
  614                 goto out;
  615         }
  616 
  617         if (symstrindex == -1)
  618                 panic("lost symbol string index");
  619         /* Allocate space for and load the symbol strings */
  620         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  621         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
  622         error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
  623             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
  624             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  625             &resid, td);
  626         if (error)
  627                 goto out;
  628         if (resid != 0){
  629                 error = EINVAL;
  630                 goto out;
  631         }
  632 
  633         /* Do we have a string table for the section names?  */
  634         shstrindex = -1;
  635         if (hdr->e_shstrndx != 0 &&
  636             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
  637                 shstrindex = hdr->e_shstrndx;
  638                 ef->shstrcnt = shdr[shstrindex].sh_size;
  639                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
  640                     M_WAITOK);
  641                 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
  642                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
  643                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  644                     &resid, td);
  645                 if (error)
  646                         goto out;
  647                 if (resid != 0){
  648                         error = EINVAL;
  649                         goto out;
  650                 }
  651         }
  652 
  653         /* Size up code/data(progbits) and bss(nobits). */
  654         alignmask = 0;
  655         for (i = 0; i < hdr->e_shnum; i++) {
  656                 if (shdr[i].sh_size == 0)
  657                         continue;
  658                 switch (shdr[i].sh_type) {
  659                 case SHT_PROGBITS:
  660                 case SHT_NOBITS:
  661                         alignmask = shdr[i].sh_addralign - 1;
  662                         mapsize += alignmask;
  663                         mapsize &= ~alignmask;
  664                         mapsize += shdr[i].sh_size;
  665                         break;
  666                 }
  667         }
  668 
  669         /*
  670          * We know how much space we need for the text/data/bss/etc.
  671          * This stuff needs to be in a single chunk so that profiling etc
  672          * can get the bounds and gdb can associate offsets with modules
  673          */
  674         ef->object = vm_object_allocate(OBJT_DEFAULT,
  675             round_page(mapsize) >> PAGE_SHIFT);
  676         if (ef->object == NULL) {
  677                 error = ENOMEM;
  678                 goto out;
  679         }
  680         ef->address = (caddr_t) vm_map_min(kernel_map);
  681 
  682         /*
  683          * In order to satisfy amd64's architectural requirements on the
  684          * location of code and data in the kernel's address space, request a
  685          * mapping that is above the kernel.  
  686          */
  687         mapbase = KERNBASE;
  688         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
  689             round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE);
  690         if (error) {
  691                 vm_object_deallocate(ef->object);
  692                 ef->object = 0;
  693                 goto out;
  694         }
  695 
  696         /* Wire the pages */
  697         error = vm_map_wire(kernel_map, mapbase,
  698             mapbase + round_page(mapsize),
  699             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  700         if (error != KERN_SUCCESS) {
  701                 error = ENOMEM;
  702                 goto out;
  703         }
  704 
  705         /* Inform the kld system about the situation */
  706         lf->address = ef->address = (caddr_t)mapbase;
  707         lf->size = mapsize;
  708 
  709         /*
  710          * Now load code/data(progbits), zero bss(nobits), allocate space for
  711          * and load relocs
  712          */
  713         pb = 0;
  714         rl = 0;
  715         ra = 0;
  716         alignmask = 0;
  717         for (i = 0; i < hdr->e_shnum; i++) {
  718                 if (shdr[i].sh_size == 0)
  719                         continue;
  720                 switch (shdr[i].sh_type) {
  721                 case SHT_PROGBITS:
  722                 case SHT_NOBITS:
  723                         alignmask = shdr[i].sh_addralign - 1;
  724                         mapbase += alignmask;
  725                         mapbase &= ~alignmask;
  726                         if (ef->shstrtab && shdr[i].sh_name != 0)
  727                                 ef->progtab[pb].name =
  728                                     ef->shstrtab + shdr[i].sh_name;
  729                         else if (shdr[i].sh_type == SHT_PROGBITS)
  730                                 ef->progtab[pb].name = "<<PROGBITS>>";
  731                         else
  732                                 ef->progtab[pb].name = "<<NOBITS>>";
  733                         if (ef->progtab[pb].name != NULL && 
  734                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
  735                                 ef->progtab[pb].addr =
  736                                     dpcpu_alloc(shdr[i].sh_size);
  737 #ifdef VIMAGE
  738                         else if (ef->progtab[pb].name != NULL &&
  739                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
  740                                 ef->progtab[pb].addr =
  741                                     vnet_data_alloc(shdr[i].sh_size);
  742 #endif
  743                         else
  744                                 ef->progtab[pb].addr =
  745                                     (void *)(uintptr_t)mapbase;
  746                         if (ef->progtab[pb].addr == NULL) {
  747                                 error = ENOSPC;
  748                                 goto out;
  749                         }
  750                         ef->progtab[pb].size = shdr[i].sh_size;
  751                         ef->progtab[pb].sec = i;
  752                         if (shdr[i].sh_type == SHT_PROGBITS) {
  753                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
  754                                     ef->progtab[pb].addr,
  755                                     shdr[i].sh_size, shdr[i].sh_offset,
  756                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  757                                     NOCRED, &resid, td);
  758                                 if (error)
  759                                         goto out;
  760                                 if (resid != 0){
  761                                         error = EINVAL;
  762                                         goto out;
  763                                 }
  764                                 /* Initialize the per-cpu or vnet area. */
  765                                 if (ef->progtab[pb].addr != (void *)mapbase &&
  766                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
  767                                         dpcpu_copy(ef->progtab[pb].addr,
  768                                             shdr[i].sh_size);
  769 #ifdef VIMAGE
  770                                 else if (ef->progtab[pb].addr !=
  771                                     (void *)mapbase &&
  772                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
  773                                         vnet_data_copy(ef->progtab[pb].addr,
  774                                             shdr[i].sh_size);
  775 #endif
  776                         } else
  777                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
  778 
  779                         /* Update all symbol values with the offset. */
  780                         for (j = 0; j < ef->ddbsymcnt; j++) {
  781                                 es = &ef->ddbsymtab[j];
  782                                 if (es->st_shndx != i)
  783                                         continue;
  784                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  785                         }
  786                         mapbase += shdr[i].sh_size;
  787                         pb++;
  788                         break;
  789                 case SHT_REL:
  790                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
  791                             M_WAITOK);
  792                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  793                         ef->reltab[rl].sec = shdr[i].sh_info;
  794                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  795                             (void *)ef->reltab[rl].rel,
  796                             shdr[i].sh_size, shdr[i].sh_offset,
  797                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  798                             &resid, td);
  799                         if (error)
  800                                 goto out;
  801                         if (resid != 0){
  802                                 error = EINVAL;
  803                                 goto out;
  804                         }
  805                         rl++;
  806                         break;
  807                 case SHT_RELA:
  808                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
  809                             M_WAITOK);
  810                         ef->relatab[ra].nrela =
  811                             shdr[i].sh_size / sizeof(Elf_Rela);
  812                         ef->relatab[ra].sec = shdr[i].sh_info;
  813                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  814                             (void *)ef->relatab[ra].rela,
  815                             shdr[i].sh_size, shdr[i].sh_offset,
  816                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  817                             &resid, td);
  818                         if (error)
  819                                 goto out;
  820                         if (resid != 0){
  821                                 error = EINVAL;
  822                                 goto out;
  823                         }
  824                         ra++;
  825                         break;
  826                 }
  827         }
  828         if (pb != ef->nprogtab)
  829                 panic("lost progbits");
  830         if (rl != ef->nreltab)
  831                 panic("lost reltab");
  832         if (ra != ef->nrelatab)
  833                 panic("lost relatab");
  834         if (mapbase != (vm_offset_t)ef->address + mapsize)
  835                 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
  836                     (u_long)mapbase, ef->address, (u_long)mapsize,
  837                     (u_long)(vm_offset_t)ef->address + mapsize);
  838 
  839         /* Local intra-module relocations */
  840         link_elf_reloc_local(lf);
  841 
  842         /* Pull in dependencies */
  843         VOP_UNLOCK(nd.ni_vp, 0);
  844         error = linker_load_dependencies(lf);
  845         vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
  846         if (error)
  847                 goto out;
  848 
  849         /* External relocations */
  850         error = relocate_file(ef);
  851         if (error)
  852                 goto out;
  853 
  854         /* Notify MD code that a module is being loaded. */
  855         error = elf_cpu_load_file(lf);
  856         if (error)
  857                 goto out;
  858 
  859         *result = lf;
  860 
  861 out:
  862         VOP_UNLOCK(nd.ni_vp, 0);
  863         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  864         VFS_UNLOCK_GIANT(vfslocked);
  865         if (error && lf)
  866                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  867         if (hdr)
  868                 free(hdr, M_LINKER);
  869 
  870         return error;
  871 }
  872 
  873 static void
  874 link_elf_unload_file(linker_file_t file)
  875 {
  876         elf_file_t ef = (elf_file_t) file;
  877         int i;
  878 
  879         /* Notify MD code that a module is being unloaded. */
  880         elf_cpu_unload_file(file);
  881 
  882         if (ef->progtab) {
  883                 for (i = 0; i < ef->nprogtab; i++) {
  884                         if (ef->progtab[i].size == 0)
  885                                 continue;
  886                         if (ef->progtab[i].name == NULL)
  887                                 continue;
  888                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
  889                                 dpcpu_free(ef->progtab[i].addr,
  890                                     ef->progtab[i].size);
  891 #ifdef VIMAGE
  892                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
  893                                 vnet_data_free(ef->progtab[i].addr,
  894                                     ef->progtab[i].size);
  895 #endif
  896                 }
  897         }
  898         if (ef->preloaded) {
  899                 if (ef->reltab)
  900                         free(ef->reltab, M_LINKER);
  901                 if (ef->relatab)
  902                         free(ef->relatab, M_LINKER);
  903                 if (ef->progtab)
  904                         free(ef->progtab, M_LINKER);
  905                 if (ef->ctftab)
  906                         free(ef->ctftab, M_LINKER);
  907                 if (ef->ctfoff)
  908                         free(ef->ctfoff, M_LINKER);
  909                 if (ef->typoff)
  910                         free(ef->typoff, M_LINKER);
  911                 if (file->filename != NULL)
  912                         preload_delete_name(file->filename);
  913                 /* XXX reclaim module memory? */
  914                 return;
  915         }
  916 
  917         for (i = 0; i < ef->nreltab; i++)
  918                 if (ef->reltab[i].rel)
  919                         free(ef->reltab[i].rel, M_LINKER);
  920         for (i = 0; i < ef->nrelatab; i++)
  921                 if (ef->relatab[i].rela)
  922                         free(ef->relatab[i].rela, M_LINKER);
  923         if (ef->reltab)
  924                 free(ef->reltab, M_LINKER);
  925         if (ef->relatab)
  926                 free(ef->relatab, M_LINKER);
  927         if (ef->progtab)
  928                 free(ef->progtab, M_LINKER);
  929 
  930         if (ef->object) {
  931                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
  932                     (vm_offset_t) ef->address +
  933                     (ef->object->size << PAGE_SHIFT));
  934         }
  935         if (ef->e_shdr)
  936                 free(ef->e_shdr, M_LINKER);
  937         if (ef->ddbsymtab)
  938                 free(ef->ddbsymtab, M_LINKER);
  939         if (ef->ddbstrtab)
  940                 free(ef->ddbstrtab, M_LINKER);
  941         if (ef->shstrtab)
  942                 free(ef->shstrtab, M_LINKER);
  943         if (ef->ctftab)
  944                 free(ef->ctftab, M_LINKER);
  945         if (ef->ctfoff)
  946                 free(ef->ctfoff, M_LINKER);
  947         if (ef->typoff)
  948                 free(ef->typoff, M_LINKER);
  949 }
  950 
  951 static const char *
  952 symbol_name(elf_file_t ef, Elf_Size r_info)
  953 {
  954         const Elf_Sym *ref;
  955 
  956         if (ELF_R_SYM(r_info)) {
  957                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
  958                 return ef->ddbstrtab + ref->st_name;
  959         } else
  960                 return NULL;
  961 }
  962 
  963 static Elf_Addr
  964 findbase(elf_file_t ef, int sec)
  965 {
  966         int i;
  967         Elf_Addr base = 0;
  968 
  969         for (i = 0; i < ef->nprogtab; i++) {
  970                 if (sec == ef->progtab[i].sec) {
  971                         base = (Elf_Addr)ef->progtab[i].addr;
  972                         break;
  973                 }
  974         }
  975         return base;
  976 }
  977 
  978 static int
  979 relocate_file(elf_file_t ef)
  980 {
  981         const Elf_Rel *rellim;
  982         const Elf_Rel *rel;
  983         const Elf_Rela *relalim;
  984         const Elf_Rela *rela;
  985         const char *symname;
  986         const Elf_Sym *sym;
  987         int i;
  988         Elf_Size symidx;
  989         Elf_Addr base;
  990 
  991 
  992         /* Perform relocations without addend if there are any: */
  993         for (i = 0; i < ef->nreltab; i++) {
  994                 rel = ef->reltab[i].rel;
  995                 if (rel == NULL)
  996                         panic("lost a reltab!");
  997                 rellim = rel + ef->reltab[i].nrel;
  998                 base = findbase(ef, ef->reltab[i].sec);
  999                 if (base == 0)
 1000                         panic("lost base for reltab");
 1001                 for ( ; rel < rellim; rel++) {
 1002                         symidx = ELF_R_SYM(rel->r_info);
 1003                         if (symidx >= ef->ddbsymcnt)
 1004                                 continue;
 1005                         sym = ef->ddbsymtab + symidx;
 1006                         /* Local relocs are already done */
 1007                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 1008                                 continue;
 1009                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
 1010                             elf_obj_lookup)) {
 1011                                 symname = symbol_name(ef, rel->r_info);
 1012                                 printf("link_elf_obj: symbol %s undefined\n",
 1013                                     symname);
 1014                                 return ENOENT;
 1015                         }
 1016                 }
 1017         }
 1018 
 1019         /* Perform relocations with addend if there are any: */
 1020         for (i = 0; i < ef->nrelatab; i++) {
 1021                 rela = ef->relatab[i].rela;
 1022                 if (rela == NULL)
 1023                         panic("lost a relatab!");
 1024                 relalim = rela + ef->relatab[i].nrela;
 1025                 base = findbase(ef, ef->relatab[i].sec);
 1026                 if (base == 0)
 1027                         panic("lost base for relatab");
 1028                 for ( ; rela < relalim; rela++) {
 1029                         symidx = ELF_R_SYM(rela->r_info);
 1030                         if (symidx >= ef->ddbsymcnt)
 1031                                 continue;
 1032                         sym = ef->ddbsymtab + symidx;
 1033                         /* Local relocs are already done */
 1034                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 1035                                 continue;
 1036                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
 1037                             elf_obj_lookup)) {
 1038                                 symname = symbol_name(ef, rela->r_info);
 1039                                 printf("link_elf_obj: symbol %s undefined\n",
 1040                                     symname);
 1041                                 return ENOENT;
 1042                         }
 1043                 }
 1044         }
 1045 
 1046         return 0;
 1047 }
 1048 
 1049 static int
 1050 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
 1051 {
 1052         elf_file_t ef = (elf_file_t) lf;
 1053         const Elf_Sym *symp;
 1054         const char *strp;
 1055         int i;
 1056 
 1057         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1058                 strp = ef->ddbstrtab + symp->st_name;
 1059                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
 1060                         *sym = (c_linker_sym_t) symp;
 1061                         return 0;
 1062                 }
 1063         }
 1064         return ENOENT;
 1065 }
 1066 
 1067 static int
 1068 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
 1069     linker_symval_t *symval)
 1070 {
 1071         elf_file_t ef = (elf_file_t) lf;
 1072         const Elf_Sym *es = (const Elf_Sym*) sym;
 1073 
 1074         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 1075                 symval->name = ef->ddbstrtab + es->st_name;
 1076                 symval->value = (caddr_t)es->st_value;
 1077                 symval->size = es->st_size;
 1078                 return 0;
 1079         }
 1080         return ENOENT;
 1081 }
 1082 
 1083 static int
 1084 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 1085     c_linker_sym_t *sym, long *diffp)
 1086 {
 1087         elf_file_t ef = (elf_file_t) lf;
 1088         u_long off = (uintptr_t) (void *) value;
 1089         u_long diff = off;
 1090         u_long st_value;
 1091         const Elf_Sym *es;
 1092         const Elf_Sym *best = 0;
 1093         int i;
 1094 
 1095         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 1096                 if (es->st_name == 0)
 1097                         continue;
 1098                 st_value = es->st_value;
 1099                 if (off >= st_value) {
 1100                         if (off - st_value < diff) {
 1101                                 diff = off - st_value;
 1102                                 best = es;
 1103                                 if (diff == 0)
 1104                                         break;
 1105                         } else if (off - st_value == diff) {
 1106                                 best = es;
 1107                         }
 1108                 }
 1109         }
 1110         if (best == 0)
 1111                 *diffp = off;
 1112         else
 1113                 *diffp = diff;
 1114         *sym = (c_linker_sym_t) best;
 1115 
 1116         return 0;
 1117 }
 1118 
 1119 /*
 1120  * Look up a linker set on an ELF system.
 1121  */
 1122 static int
 1123 link_elf_lookup_set(linker_file_t lf, const char *name,
 1124     void ***startp, void ***stopp, int *countp)
 1125 {
 1126         elf_file_t ef = (elf_file_t)lf;
 1127         void **start, **stop;
 1128         int i, count;
 1129 
 1130         /* Relative to section number */
 1131         for (i = 0; i < ef->nprogtab; i++) {
 1132                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
 1133                     strcmp(ef->progtab[i].name + 4, name) == 0) {
 1134                         start  = (void **)ef->progtab[i].addr;
 1135                         stop = (void **)((char *)ef->progtab[i].addr +
 1136                             ef->progtab[i].size);
 1137                         count = stop - start;
 1138                         if (startp)
 1139                                 *startp = start;
 1140                         if (stopp)
 1141                                 *stopp = stop;
 1142                         if (countp)
 1143                                 *countp = count;
 1144                         return (0);
 1145                 }
 1146         }
 1147         return (ESRCH);
 1148 }
 1149 
 1150 static int
 1151 link_elf_each_function_name(linker_file_t file,
 1152     int (*callback)(const char *, void *), void *opaque)
 1153 {
 1154         elf_file_t ef = (elf_file_t)file;
 1155         const Elf_Sym *symp;
 1156         int i, error;
 1157         
 1158         /* Exhaustive search */
 1159         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1160                 if (symp->st_value != 0 &&
 1161                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1162                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
 1163                         if (error)
 1164                                 return (error);
 1165                 }
 1166         }
 1167         return (0);
 1168 }
 1169 
 1170 static int
 1171 link_elf_each_function_nameval(linker_file_t file,
 1172     linker_function_nameval_callback_t callback, void *opaque)
 1173 {
 1174         linker_symval_t symval;
 1175         elf_file_t ef = (elf_file_t)file;
 1176         const Elf_Sym* symp;
 1177         int i, error;
 1178 
 1179         /* Exhaustive search */
 1180         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1181                 if (symp->st_value != 0 &&
 1182                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1183                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
 1184                         if (error)
 1185                                 return (error);
 1186                         error = callback(file, i, &symval, opaque);
 1187                         if (error)
 1188                                 return (error);
 1189                 }
 1190         }
 1191         return (0);
 1192 }
 1193 
 1194 /*
 1195  * Symbol lookup function that can be used when the symbol index is known (ie
 1196  * in relocations). It uses the symbol index instead of doing a fully fledged
 1197  * hash table based lookup when such is valid. For example for local symbols.
 1198  * This is not only more efficient, it's also more correct. It's not always
 1199  * the case that the symbol can be found through the hash table.
 1200  */
 1201 static Elf_Addr
 1202 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
 1203 {
 1204         elf_file_t ef = (elf_file_t)lf;
 1205         const Elf_Sym *sym;
 1206         const char *symbol;
 1207         Elf_Addr ret;
 1208 
 1209         /* Don't even try to lookup the symbol if the index is bogus. */
 1210         if (symidx >= ef->ddbsymcnt)
 1211                 return (0);
 1212 
 1213         sym = ef->ddbsymtab + symidx;
 1214 
 1215         /* Quick answer if there is a definition included. */
 1216         if (sym->st_shndx != SHN_UNDEF)
 1217                 return (sym->st_value);
 1218 
 1219         /* If we get here, then it is undefined and needs a lookup. */
 1220         switch (ELF_ST_BIND(sym->st_info)) {
 1221         case STB_LOCAL:
 1222                 /* Local, but undefined? huh? */
 1223                 return (0);
 1224 
 1225         case STB_GLOBAL:
 1226                 /* Relative to Data or Function name */
 1227                 symbol = ef->ddbstrtab + sym->st_name;
 1228 
 1229                 /* Force a lookup failure if the symbol name is bogus. */
 1230                 if (*symbol == 0)
 1231                         return (0);
 1232                 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
 1233                 return ret;
 1234 
 1235         case STB_WEAK:
 1236                 printf("link_elf_obj: Weak symbols not supported\n");
 1237                 return (0);
 1238 
 1239         default:
 1240                 return (0);
 1241         }
 1242 }
 1243 
 1244 static void
 1245 link_elf_fix_link_set(elf_file_t ef)
 1246 {
 1247         static const char startn[] = "__start_";
 1248         static const char stopn[] = "__stop_";
 1249         Elf_Sym *sym;
 1250         const char *sym_name, *linkset_name;
 1251         Elf_Addr startp, stopp;
 1252         Elf_Size symidx;
 1253         int start, i;
 1254 
 1255         startp = stopp = 0;
 1256         for (symidx = 1 /* zero entry is special */;
 1257                 symidx < ef->ddbsymcnt; symidx++) {
 1258                 sym = ef->ddbsymtab + symidx;
 1259                 if (sym->st_shndx != SHN_UNDEF)
 1260                         continue;
 1261 
 1262                 sym_name = ef->ddbstrtab + sym->st_name;
 1263                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
 1264                         start = 1;
 1265                         linkset_name = sym_name + sizeof(startn) - 1;
 1266                 }
 1267                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
 1268                         start = 0;
 1269                         linkset_name = sym_name + sizeof(stopn) - 1;
 1270                 }
 1271                 else
 1272                         continue;
 1273 
 1274                 for (i = 0; i < ef->nprogtab; i++) {
 1275                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
 1276                                 startp = (Elf_Addr)ef->progtab[i].addr;
 1277                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
 1278                                 break;
 1279                         }
 1280                 }
 1281                 if (i == ef->nprogtab)
 1282                         continue;
 1283 
 1284                 sym->st_value = start ? startp : stopp;
 1285                 sym->st_shndx = i;
 1286         }
 1287 }
 1288 
 1289 static void
 1290 link_elf_reloc_local(linker_file_t lf)
 1291 {
 1292         elf_file_t ef = (elf_file_t)lf;
 1293         const Elf_Rel *rellim;
 1294         const Elf_Rel *rel;
 1295         const Elf_Rela *relalim;
 1296         const Elf_Rela *rela;
 1297         const Elf_Sym *sym;
 1298         Elf_Addr base;
 1299         int i;
 1300         Elf_Size symidx;
 1301 
 1302         link_elf_fix_link_set(ef);
 1303 
 1304         /* Perform relocations without addend if there are any: */
 1305         for (i = 0; i < ef->nreltab; i++) {
 1306                 rel = ef->reltab[i].rel;
 1307                 if (rel == NULL)
 1308                         panic("lost a reltab!");
 1309                 rellim = rel + ef->reltab[i].nrel;
 1310                 base = findbase(ef, ef->reltab[i].sec);
 1311                 if (base == 0)
 1312                         panic("lost base for reltab");
 1313                 for ( ; rel < rellim; rel++) {
 1314                         symidx = ELF_R_SYM(rel->r_info);
 1315                         if (symidx >= ef->ddbsymcnt)
 1316                                 continue;
 1317                         sym = ef->ddbsymtab + symidx;
 1318                         /* Only do local relocs */
 1319                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1320                                 continue;
 1321                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
 1322                             elf_obj_lookup);
 1323                 }
 1324         }
 1325 
 1326         /* Perform relocations with addend if there are any: */
 1327         for (i = 0; i < ef->nrelatab; i++) {
 1328                 rela = ef->relatab[i].rela;
 1329                 if (rela == NULL)
 1330                         panic("lost a relatab!");
 1331                 relalim = rela + ef->relatab[i].nrela;
 1332                 base = findbase(ef, ef->relatab[i].sec);
 1333                 if (base == 0)
 1334                         panic("lost base for relatab");
 1335                 for ( ; rela < relalim; rela++) {
 1336                         symidx = ELF_R_SYM(rela->r_info);
 1337                         if (symidx >= ef->ddbsymcnt)
 1338                                 continue;
 1339                         sym = ef->ddbsymtab + symidx;
 1340                         /* Only do local relocs */
 1341                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1342                                 continue;
 1343                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
 1344                             elf_obj_lookup);
 1345                 }
 1346         }
 1347 }
 1348 
 1349 static long
 1350 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
 1351 {
 1352     elf_file_t ef = (elf_file_t)lf;
 1353     
 1354     *symtab = ef->ddbsymtab;
 1355     
 1356     if (*symtab == NULL)
 1357         return (0);
 1358 
 1359     return (ef->ddbsymcnt);
 1360 }
 1361     
 1362 static long
 1363 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
 1364 {
 1365     elf_file_t ef = (elf_file_t)lf;
 1366 
 1367     *strtab = ef->ddbstrtab;
 1368 
 1369     if (*strtab == NULL)
 1370         return (0);
 1371 
 1372     return (ef->ddbstrcnt);
 1373 }

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