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/10.2/sys/kern/link_elf_obj.c 281880 2015-04-23 07:32:28Z kib $");
   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 static void     elf_obj_cleanup_globals_cache(elf_file_t);
  177 
  178 static void
  179 link_elf_error(const char *filename, const char *s)
  180 {
  181         if (filename == NULL)
  182                 printf("kldload: %s\n", s);
  183         else
  184                 printf("kldload: %s: %s\n", filename, s);
  185 }
  186 
  187 static void
  188 link_elf_init(void *arg)
  189 {
  190 
  191         linker_add_class(&link_elf_class);
  192 }
  193 
  194 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
  195 
  196 static int
  197 link_elf_link_preload(linker_class_t cls, const char *filename,
  198     linker_file_t *result)
  199 {
  200         Elf_Ehdr *hdr;
  201         Elf_Shdr *shdr;
  202         Elf_Sym *es;
  203         void *modptr, *baseptr, *sizeptr;
  204         char *type;
  205         elf_file_t ef;
  206         linker_file_t lf;
  207         Elf_Addr off;
  208         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
  209 
  210         /* Look to see if we have the file preloaded */
  211         modptr = preload_search_by_name(filename);
  212         if (modptr == NULL)
  213                 return ENOENT;
  214 
  215         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
  216         baseptr = preload_search_info(modptr, MODINFO_ADDR);
  217         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  218         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
  219             MODINFOMD_ELFHDR);
  220         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
  221             MODINFOMD_SHDR);
  222         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
  223             " obj module") != 0 &&
  224             strcmp(type, "elf obj module") != 0)) {
  225                 return (EFTYPE);
  226         }
  227         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
  228             shdr == NULL)
  229                 return (EINVAL);
  230 
  231         lf = linker_make_file(filename, &link_elf_class);
  232         if (lf == NULL)
  233                 return (ENOMEM);
  234 
  235         ef = (elf_file_t)lf;
  236         ef->preloaded = 1;
  237         ef->address = *(caddr_t *)baseptr;
  238         lf->address = *(caddr_t *)baseptr;
  239         lf->size = *(size_t *)sizeptr;
  240 
  241         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
  242             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
  243             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
  244             hdr->e_version != EV_CURRENT ||
  245             hdr->e_type != ET_REL ||
  246             hdr->e_machine != ELF_TARG_MACH) {
  247                 error = EFTYPE;
  248                 goto out;
  249         }
  250         ef->e_shdr = shdr;
  251 
  252         /* Scan the section header for information and table sizing. */
  253         symtabindex = -1;
  254         symstrindex = -1;
  255         for (i = 0; i < hdr->e_shnum; i++) {
  256                 switch (shdr[i].sh_type) {
  257                 case SHT_PROGBITS:
  258                 case SHT_NOBITS:
  259                         ef->nprogtab++;
  260                         break;
  261                 case SHT_SYMTAB:
  262                         symtabindex = i;
  263                         symstrindex = shdr[i].sh_link;
  264                         break;
  265                 case SHT_REL:
  266                         ef->nreltab++;
  267                         break;
  268                 case SHT_RELA:
  269                         ef->nrelatab++;
  270                         break;
  271                 }
  272         }
  273 
  274         shstrindex = hdr->e_shstrndx;
  275         if (ef->nprogtab == 0 || symstrindex < 0 ||
  276             symstrindex >= hdr->e_shnum ||
  277             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
  278             shstrindex >= hdr->e_shnum ||
  279             shdr[shstrindex].sh_type != SHT_STRTAB) {
  280                 printf("%s: bad/missing section headers\n", filename);
  281                 error = ENOEXEC;
  282                 goto out;
  283         }
  284 
  285         /* Allocate space for tracking the load chunks */
  286         if (ef->nprogtab != 0)
  287                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  288                     M_LINKER, M_WAITOK | M_ZERO);
  289         if (ef->nreltab != 0)
  290                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
  291                     M_LINKER, M_WAITOK | M_ZERO);
  292         if (ef->nrelatab != 0)
  293                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
  294                     M_LINKER, M_WAITOK | M_ZERO);
  295         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
  296             (ef->nreltab != 0 && ef->reltab == NULL) ||
  297             (ef->nrelatab != 0 && ef->relatab == NULL)) {
  298                 error = ENOMEM;
  299                 goto out;
  300         }
  301 
  302         /* XXX, relocate the sh_addr fields saved by the loader. */
  303         off = 0;
  304         for (i = 0; i < hdr->e_shnum; i++) {
  305                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
  306                         off = shdr[i].sh_addr;
  307         }
  308         for (i = 0; i < hdr->e_shnum; i++) {
  309                 if (shdr[i].sh_addr != 0)
  310                         shdr[i].sh_addr = shdr[i].sh_addr - off +
  311                             (Elf_Addr)ef->address;
  312         }
  313 
  314         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  315         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
  316         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  317         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
  318         ef->shstrcnt = shdr[shstrindex].sh_size;
  319         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
  320 
  321         /* Now fill out progtab and the relocation tables. */
  322         pb = 0;
  323         rl = 0;
  324         ra = 0;
  325         for (i = 0; i < hdr->e_shnum; i++) {
  326                 switch (shdr[i].sh_type) {
  327                 case SHT_PROGBITS:
  328                 case SHT_NOBITS:
  329                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
  330                         if (shdr[i].sh_type == SHT_PROGBITS)
  331                                 ef->progtab[pb].name = "<<PROGBITS>>";
  332                         else
  333                                 ef->progtab[pb].name = "<<NOBITS>>";
  334                         ef->progtab[pb].size = shdr[i].sh_size;
  335                         ef->progtab[pb].sec = i;
  336                         if (ef->shstrtab && shdr[i].sh_name != 0)
  337                                 ef->progtab[pb].name =
  338                                     ef->shstrtab + shdr[i].sh_name;
  339                         if (ef->progtab[pb].name != NULL && 
  340                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
  341                                 void *dpcpu;
  342 
  343                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
  344                                 if (dpcpu == NULL) {
  345                                         error = ENOSPC;
  346                                         goto out;
  347                                 }
  348                                 memcpy(dpcpu, ef->progtab[pb].addr,
  349                                     ef->progtab[pb].size);
  350                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
  351                                 ef->progtab[pb].addr = dpcpu;
  352 #ifdef VIMAGE
  353                         } else if (ef->progtab[pb].name != NULL &&
  354                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
  355                                 void *vnet_data;
  356 
  357                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
  358                                 if (vnet_data == NULL) {
  359                                         error = ENOSPC;
  360                                         goto out;
  361                                 }
  362                                 memcpy(vnet_data, ef->progtab[pb].addr,
  363                                     ef->progtab[pb].size);
  364                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
  365                                 ef->progtab[pb].addr = vnet_data;
  366 #endif
  367                         }
  368 
  369                         /* Update all symbol values with the offset. */
  370                         for (j = 0; j < ef->ddbsymcnt; j++) {
  371                                 es = &ef->ddbsymtab[j];
  372                                 if (es->st_shndx != i)
  373                                         continue;
  374                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  375                         }
  376                         pb++;
  377                         break;
  378                 case SHT_REL:
  379                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
  380                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  381                         ef->reltab[rl].sec = shdr[i].sh_info;
  382                         rl++;
  383                         break;
  384                 case SHT_RELA:
  385                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
  386                         ef->relatab[ra].nrela =
  387                             shdr[i].sh_size / sizeof(Elf_Rela);
  388                         ef->relatab[ra].sec = shdr[i].sh_info;
  389                         ra++;
  390                         break;
  391                 }
  392         }
  393         if (pb != ef->nprogtab)
  394                 panic("lost progbits");
  395         if (rl != ef->nreltab)
  396                 panic("lost reltab");
  397         if (ra != ef->nrelatab)
  398                 panic("lost relatab");
  399 
  400         /* Local intra-module relocations */
  401         link_elf_reloc_local(lf);
  402 
  403         *result = lf;
  404         return (0);
  405 
  406 out:
  407         /* preload not done this way */
  408         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  409         return (error);
  410 }
  411 
  412 static int
  413 link_elf_link_preload_finish(linker_file_t lf)
  414 {
  415         elf_file_t ef;
  416         int error;
  417 
  418         ef = (elf_file_t)lf;
  419         error = relocate_file(ef);
  420         if (error)
  421                 return error;
  422 
  423         /* Notify MD code that a module is being loaded. */
  424         error = elf_cpu_load_file(lf);
  425         if (error)
  426                 return (error);
  427 
  428         return (0);
  429 }
  430 
  431 static int
  432 link_elf_load_file(linker_class_t cls, const char *filename,
  433     linker_file_t *result)
  434 {
  435         struct nameidata nd;
  436         struct thread *td = curthread;  /* XXX */
  437         Elf_Ehdr *hdr;
  438         Elf_Shdr *shdr;
  439         Elf_Sym *es;
  440         int nbytes, i, j;
  441         vm_offset_t mapbase;
  442         size_t mapsize;
  443         int error = 0;
  444         ssize_t resid;
  445         int flags;
  446         elf_file_t ef;
  447         linker_file_t lf;
  448         int symtabindex;
  449         int symstrindex;
  450         int shstrindex;
  451         int nsym;
  452         int pb, rl, ra;
  453         int alignmask;
  454 
  455         shdr = NULL;
  456         lf = NULL;
  457         mapsize = 0;
  458         hdr = NULL;
  459 
  460         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
  461         flags = FREAD;
  462         error = vn_open(&nd, &flags, 0, NULL);
  463         if (error)
  464                 return error;
  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 #ifdef __amd64__
  688         mapbase = KERNBASE;
  689 #else
  690         mapbase = VM_MIN_KERNEL_ADDRESS;
  691 #endif
  692         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
  693             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
  694             VM_PROT_ALL, 0);
  695         if (error) {
  696                 vm_object_deallocate(ef->object);
  697                 ef->object = 0;
  698                 goto out;
  699         }
  700 
  701         /* Wire the pages */
  702         error = vm_map_wire(kernel_map, mapbase,
  703             mapbase + round_page(mapsize),
  704             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  705         if (error != KERN_SUCCESS) {
  706                 error = ENOMEM;
  707                 goto out;
  708         }
  709 
  710         /* Inform the kld system about the situation */
  711         lf->address = ef->address = (caddr_t)mapbase;
  712         lf->size = mapsize;
  713 
  714         /*
  715          * Now load code/data(progbits), zero bss(nobits), allocate space for
  716          * and load relocs
  717          */
  718         pb = 0;
  719         rl = 0;
  720         ra = 0;
  721         alignmask = 0;
  722         for (i = 0; i < hdr->e_shnum; i++) {
  723                 if (shdr[i].sh_size == 0)
  724                         continue;
  725                 switch (shdr[i].sh_type) {
  726                 case SHT_PROGBITS:
  727                 case SHT_NOBITS:
  728                         alignmask = shdr[i].sh_addralign - 1;
  729                         mapbase += alignmask;
  730                         mapbase &= ~alignmask;
  731                         if (ef->shstrtab && shdr[i].sh_name != 0)
  732                                 ef->progtab[pb].name =
  733                                     ef->shstrtab + shdr[i].sh_name;
  734                         else if (shdr[i].sh_type == SHT_PROGBITS)
  735                                 ef->progtab[pb].name = "<<PROGBITS>>";
  736                         else
  737                                 ef->progtab[pb].name = "<<NOBITS>>";
  738                         if (ef->progtab[pb].name != NULL && 
  739                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
  740                                 ef->progtab[pb].addr =
  741                                     dpcpu_alloc(shdr[i].sh_size);
  742 #ifdef VIMAGE
  743                         else if (ef->progtab[pb].name != NULL &&
  744                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
  745                                 ef->progtab[pb].addr =
  746                                     vnet_data_alloc(shdr[i].sh_size);
  747 #endif
  748                         else
  749                                 ef->progtab[pb].addr =
  750                                     (void *)(uintptr_t)mapbase;
  751                         if (ef->progtab[pb].addr == NULL) {
  752                                 error = ENOSPC;
  753                                 goto out;
  754                         }
  755                         ef->progtab[pb].size = shdr[i].sh_size;
  756                         ef->progtab[pb].sec = i;
  757                         if (shdr[i].sh_type == SHT_PROGBITS) {
  758                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
  759                                     ef->progtab[pb].addr,
  760                                     shdr[i].sh_size, shdr[i].sh_offset,
  761                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  762                                     NOCRED, &resid, td);
  763                                 if (error)
  764                                         goto out;
  765                                 if (resid != 0){
  766                                         error = EINVAL;
  767                                         goto out;
  768                                 }
  769                                 /* Initialize the per-cpu or vnet area. */
  770                                 if (ef->progtab[pb].addr != (void *)mapbase &&
  771                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
  772                                         dpcpu_copy(ef->progtab[pb].addr,
  773                                             shdr[i].sh_size);
  774 #ifdef VIMAGE
  775                                 else if (ef->progtab[pb].addr !=
  776                                     (void *)mapbase &&
  777                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
  778                                         vnet_data_copy(ef->progtab[pb].addr,
  779                                             shdr[i].sh_size);
  780 #endif
  781                         } else
  782                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
  783 
  784                         /* Update all symbol values with the offset. */
  785                         for (j = 0; j < ef->ddbsymcnt; j++) {
  786                                 es = &ef->ddbsymtab[j];
  787                                 if (es->st_shndx != i)
  788                                         continue;
  789                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  790                         }
  791                         mapbase += shdr[i].sh_size;
  792                         pb++;
  793                         break;
  794                 case SHT_REL:
  795                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
  796                             M_WAITOK);
  797                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  798                         ef->reltab[rl].sec = shdr[i].sh_info;
  799                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  800                             (void *)ef->reltab[rl].rel,
  801                             shdr[i].sh_size, shdr[i].sh_offset,
  802                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  803                             &resid, td);
  804                         if (error)
  805                                 goto out;
  806                         if (resid != 0){
  807                                 error = EINVAL;
  808                                 goto out;
  809                         }
  810                         rl++;
  811                         break;
  812                 case SHT_RELA:
  813                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
  814                             M_WAITOK);
  815                         ef->relatab[ra].nrela =
  816                             shdr[i].sh_size / sizeof(Elf_Rela);
  817                         ef->relatab[ra].sec = shdr[i].sh_info;
  818                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  819                             (void *)ef->relatab[ra].rela,
  820                             shdr[i].sh_size, shdr[i].sh_offset,
  821                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  822                             &resid, td);
  823                         if (error)
  824                                 goto out;
  825                         if (resid != 0){
  826                                 error = EINVAL;
  827                                 goto out;
  828                         }
  829                         ra++;
  830                         break;
  831                 }
  832         }
  833         if (pb != ef->nprogtab)
  834                 panic("lost progbits");
  835         if (rl != ef->nreltab)
  836                 panic("lost reltab");
  837         if (ra != ef->nrelatab)
  838                 panic("lost relatab");
  839         if (mapbase != (vm_offset_t)ef->address + mapsize)
  840                 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
  841                     (u_long)mapbase, ef->address, (u_long)mapsize,
  842                     (u_long)(vm_offset_t)ef->address + mapsize);
  843 
  844         /* Local intra-module relocations */
  845         link_elf_reloc_local(lf);
  846 
  847         /* Pull in dependencies */
  848         VOP_UNLOCK(nd.ni_vp, 0);
  849         error = linker_load_dependencies(lf);
  850         vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
  851         if (error)
  852                 goto out;
  853 
  854         /* External relocations */
  855         error = relocate_file(ef);
  856         if (error)
  857                 goto out;
  858 
  859         /* Notify MD code that a module is being loaded. */
  860         error = elf_cpu_load_file(lf);
  861         if (error)
  862                 goto out;
  863 
  864         *result = lf;
  865 
  866 out:
  867         VOP_UNLOCK(nd.ni_vp, 0);
  868         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  869         if (error && lf)
  870                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  871         if (hdr)
  872                 free(hdr, M_LINKER);
  873 
  874         return error;
  875 }
  876 
  877 static void
  878 link_elf_unload_file(linker_file_t file)
  879 {
  880         elf_file_t ef = (elf_file_t) file;
  881         int i;
  882 
  883         /* Notify MD code that a module is being unloaded. */
  884         elf_cpu_unload_file(file);
  885 
  886         if (ef->progtab) {
  887                 for (i = 0; i < ef->nprogtab; i++) {
  888                         if (ef->progtab[i].size == 0)
  889                                 continue;
  890                         if (ef->progtab[i].name == NULL)
  891                                 continue;
  892                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
  893                                 dpcpu_free(ef->progtab[i].addr,
  894                                     ef->progtab[i].size);
  895 #ifdef VIMAGE
  896                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
  897                                 vnet_data_free(ef->progtab[i].addr,
  898                                     ef->progtab[i].size);
  899 #endif
  900                 }
  901         }
  902         if (ef->preloaded) {
  903                 if (ef->reltab)
  904                         free(ef->reltab, M_LINKER);
  905                 if (ef->relatab)
  906                         free(ef->relatab, M_LINKER);
  907                 if (ef->progtab)
  908                         free(ef->progtab, M_LINKER);
  909                 if (ef->ctftab)
  910                         free(ef->ctftab, M_LINKER);
  911                 if (ef->ctfoff)
  912                         free(ef->ctfoff, M_LINKER);
  913                 if (ef->typoff)
  914                         free(ef->typoff, M_LINKER);
  915                 if (file->filename != NULL)
  916                         preload_delete_name(file->filename);
  917                 /* XXX reclaim module memory? */
  918                 return;
  919         }
  920 
  921         for (i = 0; i < ef->nreltab; i++)
  922                 if (ef->reltab[i].rel)
  923                         free(ef->reltab[i].rel, M_LINKER);
  924         for (i = 0; i < ef->nrelatab; i++)
  925                 if (ef->relatab[i].rela)
  926                         free(ef->relatab[i].rela, M_LINKER);
  927         if (ef->reltab)
  928                 free(ef->reltab, M_LINKER);
  929         if (ef->relatab)
  930                 free(ef->relatab, M_LINKER);
  931         if (ef->progtab)
  932                 free(ef->progtab, M_LINKER);
  933 
  934         if (ef->object) {
  935                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
  936                     (vm_offset_t) ef->address +
  937                     (ef->object->size << PAGE_SHIFT));
  938         }
  939         if (ef->e_shdr)
  940                 free(ef->e_shdr, M_LINKER);
  941         if (ef->ddbsymtab)
  942                 free(ef->ddbsymtab, M_LINKER);
  943         if (ef->ddbstrtab)
  944                 free(ef->ddbstrtab, M_LINKER);
  945         if (ef->shstrtab)
  946                 free(ef->shstrtab, M_LINKER);
  947         if (ef->ctftab)
  948                 free(ef->ctftab, M_LINKER);
  949         if (ef->ctfoff)
  950                 free(ef->ctfoff, M_LINKER);
  951         if (ef->typoff)
  952                 free(ef->typoff, M_LINKER);
  953 }
  954 
  955 static const char *
  956 symbol_name(elf_file_t ef, Elf_Size r_info)
  957 {
  958         const Elf_Sym *ref;
  959 
  960         if (ELF_R_SYM(r_info)) {
  961                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
  962                 return ef->ddbstrtab + ref->st_name;
  963         } else
  964                 return NULL;
  965 }
  966 
  967 static Elf_Addr
  968 findbase(elf_file_t ef, int sec)
  969 {
  970         int i;
  971         Elf_Addr base = 0;
  972 
  973         for (i = 0; i < ef->nprogtab; i++) {
  974                 if (sec == ef->progtab[i].sec) {
  975                         base = (Elf_Addr)ef->progtab[i].addr;
  976                         break;
  977                 }
  978         }
  979         return base;
  980 }
  981 
  982 static int
  983 relocate_file(elf_file_t ef)
  984 {
  985         const Elf_Rel *rellim;
  986         const Elf_Rel *rel;
  987         const Elf_Rela *relalim;
  988         const Elf_Rela *rela;
  989         const char *symname;
  990         const Elf_Sym *sym;
  991         int i;
  992         Elf_Size symidx;
  993         Elf_Addr base;
  994 
  995 
  996         /* Perform relocations without addend if there are any: */
  997         for (i = 0; i < ef->nreltab; i++) {
  998                 rel = ef->reltab[i].rel;
  999                 if (rel == NULL)
 1000                         panic("lost a reltab!");
 1001                 rellim = rel + ef->reltab[i].nrel;
 1002                 base = findbase(ef, ef->reltab[i].sec);
 1003                 if (base == 0)
 1004                         panic("lost base for reltab");
 1005                 for ( ; rel < rellim; rel++) {
 1006                         symidx = ELF_R_SYM(rel->r_info);
 1007                         if (symidx >= ef->ddbsymcnt)
 1008                                 continue;
 1009                         sym = ef->ddbsymtab + symidx;
 1010                         /* Local relocs are already done */
 1011                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 1012                                 continue;
 1013                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
 1014                             elf_obj_lookup)) {
 1015                                 symname = symbol_name(ef, rel->r_info);
 1016                                 printf("link_elf_obj: symbol %s undefined\n",
 1017                                     symname);
 1018                                 return ENOENT;
 1019                         }
 1020                 }
 1021         }
 1022 
 1023         /* Perform relocations with addend if there are any: */
 1024         for (i = 0; i < ef->nrelatab; i++) {
 1025                 rela = ef->relatab[i].rela;
 1026                 if (rela == NULL)
 1027                         panic("lost a relatab!");
 1028                 relalim = rela + ef->relatab[i].nrela;
 1029                 base = findbase(ef, ef->relatab[i].sec);
 1030                 if (base == 0)
 1031                         panic("lost base for relatab");
 1032                 for ( ; rela < relalim; rela++) {
 1033                         symidx = ELF_R_SYM(rela->r_info);
 1034                         if (symidx >= ef->ddbsymcnt)
 1035                                 continue;
 1036                         sym = ef->ddbsymtab + symidx;
 1037                         /* Local relocs are already done */
 1038                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 1039                                 continue;
 1040                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
 1041                             elf_obj_lookup)) {
 1042                                 symname = symbol_name(ef, rela->r_info);
 1043                                 printf("link_elf_obj: symbol %s undefined\n",
 1044                                     symname);
 1045                                 return ENOENT;
 1046                         }
 1047                 }
 1048         }
 1049 
 1050         /*
 1051          * Only clean SHN_FBSD_CACHED for successfull return.  If we
 1052          * modified symbol table for the object but found an
 1053          * unresolved symbol, there is no reason to roll back.
 1054          */
 1055         elf_obj_cleanup_globals_cache(ef);
 1056 
 1057         return 0;
 1058 }
 1059 
 1060 static int
 1061 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
 1062 {
 1063         elf_file_t ef = (elf_file_t) lf;
 1064         const Elf_Sym *symp;
 1065         const char *strp;
 1066         int i;
 1067 
 1068         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1069                 strp = ef->ddbstrtab + symp->st_name;
 1070                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
 1071                         *sym = (c_linker_sym_t) symp;
 1072                         return 0;
 1073                 }
 1074         }
 1075         return ENOENT;
 1076 }
 1077 
 1078 static int
 1079 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
 1080     linker_symval_t *symval)
 1081 {
 1082         elf_file_t ef = (elf_file_t) lf;
 1083         const Elf_Sym *es = (const Elf_Sym*) sym;
 1084 
 1085         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 1086                 symval->name = ef->ddbstrtab + es->st_name;
 1087                 symval->value = (caddr_t)es->st_value;
 1088                 symval->size = es->st_size;
 1089                 return 0;
 1090         }
 1091         return ENOENT;
 1092 }
 1093 
 1094 static int
 1095 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 1096     c_linker_sym_t *sym, long *diffp)
 1097 {
 1098         elf_file_t ef = (elf_file_t) lf;
 1099         u_long off = (uintptr_t) (void *) value;
 1100         u_long diff = off;
 1101         u_long st_value;
 1102         const Elf_Sym *es;
 1103         const Elf_Sym *best = 0;
 1104         int i;
 1105 
 1106         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 1107                 if (es->st_name == 0)
 1108                         continue;
 1109                 st_value = es->st_value;
 1110                 if (off >= st_value) {
 1111                         if (off - st_value < diff) {
 1112                                 diff = off - st_value;
 1113                                 best = es;
 1114                                 if (diff == 0)
 1115                                         break;
 1116                         } else if (off - st_value == diff) {
 1117                                 best = es;
 1118                         }
 1119                 }
 1120         }
 1121         if (best == 0)
 1122                 *diffp = off;
 1123         else
 1124                 *diffp = diff;
 1125         *sym = (c_linker_sym_t) best;
 1126 
 1127         return 0;
 1128 }
 1129 
 1130 /*
 1131  * Look up a linker set on an ELF system.
 1132  */
 1133 static int
 1134 link_elf_lookup_set(linker_file_t lf, const char *name,
 1135     void ***startp, void ***stopp, int *countp)
 1136 {
 1137         elf_file_t ef = (elf_file_t)lf;
 1138         void **start, **stop;
 1139         int i, count;
 1140 
 1141         /* Relative to section number */
 1142         for (i = 0; i < ef->nprogtab; i++) {
 1143                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
 1144                     strcmp(ef->progtab[i].name + 4, name) == 0) {
 1145                         start  = (void **)ef->progtab[i].addr;
 1146                         stop = (void **)((char *)ef->progtab[i].addr +
 1147                             ef->progtab[i].size);
 1148                         count = stop - start;
 1149                         if (startp)
 1150                                 *startp = start;
 1151                         if (stopp)
 1152                                 *stopp = stop;
 1153                         if (countp)
 1154                                 *countp = count;
 1155                         return (0);
 1156                 }
 1157         }
 1158         return (ESRCH);
 1159 }
 1160 
 1161 static int
 1162 link_elf_each_function_name(linker_file_t file,
 1163     int (*callback)(const char *, void *), void *opaque)
 1164 {
 1165         elf_file_t ef = (elf_file_t)file;
 1166         const Elf_Sym *symp;
 1167         int i, error;
 1168         
 1169         /* Exhaustive search */
 1170         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1171                 if (symp->st_value != 0 &&
 1172                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1173                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
 1174                         if (error)
 1175                                 return (error);
 1176                 }
 1177         }
 1178         return (0);
 1179 }
 1180 
 1181 static int
 1182 link_elf_each_function_nameval(linker_file_t file,
 1183     linker_function_nameval_callback_t callback, void *opaque)
 1184 {
 1185         linker_symval_t symval;
 1186         elf_file_t ef = (elf_file_t)file;
 1187         const Elf_Sym* symp;
 1188         int i, error;
 1189 
 1190         /* Exhaustive search */
 1191         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1192                 if (symp->st_value != 0 &&
 1193                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1194                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
 1195                         if (error)
 1196                                 return (error);
 1197                         error = callback(file, i, &symval, opaque);
 1198                         if (error)
 1199                                 return (error);
 1200                 }
 1201         }
 1202         return (0);
 1203 }
 1204 
 1205 static void
 1206 elf_obj_cleanup_globals_cache(elf_file_t ef)
 1207 {
 1208         Elf_Sym *sym;
 1209         Elf_Size i;
 1210 
 1211         for (i = 0; i < ef->ddbsymcnt; i++) {
 1212                 sym = ef->ddbsymtab + i;
 1213                 if (sym->st_shndx == SHN_FBSD_CACHED) {
 1214                         sym->st_shndx = SHN_UNDEF;
 1215                         sym->st_value = 0;
 1216                 }
 1217         }
 1218 }
 1219 
 1220 /*
 1221  * Symbol lookup function that can be used when the symbol index is known (ie
 1222  * in relocations). It uses the symbol index instead of doing a fully fledged
 1223  * hash table based lookup when such is valid. For example for local symbols.
 1224  * This is not only more efficient, it's also more correct. It's not always
 1225  * the case that the symbol can be found through the hash table.
 1226  */
 1227 static Elf_Addr
 1228 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
 1229 {
 1230         elf_file_t ef = (elf_file_t)lf;
 1231         Elf_Sym *sym;
 1232         const char *symbol;
 1233         Elf_Addr ret;
 1234 
 1235         /* Don't even try to lookup the symbol if the index is bogus. */
 1236         if (symidx >= ef->ddbsymcnt)
 1237                 return (0);
 1238 
 1239         sym = ef->ddbsymtab + symidx;
 1240 
 1241         /* Quick answer if there is a definition included. */
 1242         if (sym->st_shndx != SHN_UNDEF)
 1243                 return (sym->st_value);
 1244 
 1245         /* If we get here, then it is undefined and needs a lookup. */
 1246         switch (ELF_ST_BIND(sym->st_info)) {
 1247         case STB_LOCAL:
 1248                 /* Local, but undefined? huh? */
 1249                 return (0);
 1250 
 1251         case STB_GLOBAL:
 1252                 /* Relative to Data or Function name */
 1253                 symbol = ef->ddbstrtab + sym->st_name;
 1254 
 1255                 /* Force a lookup failure if the symbol name is bogus. */
 1256                 if (*symbol == 0)
 1257                         return (0);
 1258                 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
 1259 
 1260                 /*
 1261                  * Cache global lookups during module relocation. The failure
 1262                  * case is particularly expensive for callers, who must scan
 1263                  * through the entire globals table doing strcmp(). Cache to
 1264                  * avoid doing such work repeatedly.
 1265                  *
 1266                  * After relocation is complete, undefined globals will be
 1267                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
 1268                  * above.
 1269                  */
 1270                 if (ret != 0) {
 1271                         sym->st_shndx = SHN_FBSD_CACHED;
 1272                         sym->st_value = ret;
 1273                 }
 1274                 return (ret);
 1275 
 1276         case STB_WEAK:
 1277                 printf("link_elf_obj: Weak symbols not supported\n");
 1278                 return (0);
 1279 
 1280         default:
 1281                 return (0);
 1282         }
 1283 }
 1284 
 1285 static void
 1286 link_elf_fix_link_set(elf_file_t ef)
 1287 {
 1288         static const char startn[] = "__start_";
 1289         static const char stopn[] = "__stop_";
 1290         Elf_Sym *sym;
 1291         const char *sym_name, *linkset_name;
 1292         Elf_Addr startp, stopp;
 1293         Elf_Size symidx;
 1294         int start, i;
 1295 
 1296         startp = stopp = 0;
 1297         for (symidx = 1 /* zero entry is special */;
 1298                 symidx < ef->ddbsymcnt; symidx++) {
 1299                 sym = ef->ddbsymtab + symidx;
 1300                 if (sym->st_shndx != SHN_UNDEF)
 1301                         continue;
 1302 
 1303                 sym_name = ef->ddbstrtab + sym->st_name;
 1304                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
 1305                         start = 1;
 1306                         linkset_name = sym_name + sizeof(startn) - 1;
 1307                 }
 1308                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
 1309                         start = 0;
 1310                         linkset_name = sym_name + sizeof(stopn) - 1;
 1311                 }
 1312                 else
 1313                         continue;
 1314 
 1315                 for (i = 0; i < ef->nprogtab; i++) {
 1316                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
 1317                                 startp = (Elf_Addr)ef->progtab[i].addr;
 1318                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
 1319                                 break;
 1320                         }
 1321                 }
 1322                 if (i == ef->nprogtab)
 1323                         continue;
 1324 
 1325                 sym->st_value = start ? startp : stopp;
 1326                 sym->st_shndx = i;
 1327         }
 1328 }
 1329 
 1330 static void
 1331 link_elf_reloc_local(linker_file_t lf)
 1332 {
 1333         elf_file_t ef = (elf_file_t)lf;
 1334         const Elf_Rel *rellim;
 1335         const Elf_Rel *rel;
 1336         const Elf_Rela *relalim;
 1337         const Elf_Rela *rela;
 1338         const Elf_Sym *sym;
 1339         Elf_Addr base;
 1340         int i;
 1341         Elf_Size symidx;
 1342 
 1343         link_elf_fix_link_set(ef);
 1344 
 1345         /* Perform relocations without addend if there are any: */
 1346         for (i = 0; i < ef->nreltab; i++) {
 1347                 rel = ef->reltab[i].rel;
 1348                 if (rel == NULL)
 1349                         panic("lost a reltab!");
 1350                 rellim = rel + ef->reltab[i].nrel;
 1351                 base = findbase(ef, ef->reltab[i].sec);
 1352                 if (base == 0)
 1353                         panic("lost base for reltab");
 1354                 for ( ; rel < rellim; rel++) {
 1355                         symidx = ELF_R_SYM(rel->r_info);
 1356                         if (symidx >= ef->ddbsymcnt)
 1357                                 continue;
 1358                         sym = ef->ddbsymtab + symidx;
 1359                         /* Only do local relocs */
 1360                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1361                                 continue;
 1362                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
 1363                             elf_obj_lookup);
 1364                 }
 1365         }
 1366 
 1367         /* Perform relocations with addend if there are any: */
 1368         for (i = 0; i < ef->nrelatab; i++) {
 1369                 rela = ef->relatab[i].rela;
 1370                 if (rela == NULL)
 1371                         panic("lost a relatab!");
 1372                 relalim = rela + ef->relatab[i].nrela;
 1373                 base = findbase(ef, ef->relatab[i].sec);
 1374                 if (base == 0)
 1375                         panic("lost base for relatab");
 1376                 for ( ; rela < relalim; rela++) {
 1377                         symidx = ELF_R_SYM(rela->r_info);
 1378                         if (symidx >= ef->ddbsymcnt)
 1379                                 continue;
 1380                         sym = ef->ddbsymtab + symidx;
 1381                         /* Only do local relocs */
 1382                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1383                                 continue;
 1384                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
 1385                             elf_obj_lookup);
 1386                 }
 1387         }
 1388 }
 1389 
 1390 static long
 1391 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
 1392 {
 1393     elf_file_t ef = (elf_file_t)lf;
 1394     
 1395     *symtab = ef->ddbsymtab;
 1396     
 1397     if (*symtab == NULL)
 1398         return (0);
 1399 
 1400     return (ef->ddbsymcnt);
 1401 }
 1402     
 1403 static long
 1404 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
 1405 {
 1406     elf_file_t ef = (elf_file_t)lf;
 1407 
 1408     *strtab = ef->ddbstrtab;
 1409 
 1410     if (*strtab == NULL)
 1411         return (0);
 1412 
 1413     return (ef->ddbstrcnt);
 1414 }

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