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/6.0/sys/kern/link_elf_obj.c 151023 2005-10-06 19:01:42Z delphij $");
   30 
   31 #include "opt_ddb.h"
   32 #include "opt_mac.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/kernel.h>
   37 #include <sys/lock.h>
   38 #include <sys/mac.h>
   39 #include <sys/malloc.h>
   40 #include <sys/mutex.h>
   41 #include <sys/proc.h>
   42 #include <sys/namei.h>
   43 #include <sys/fcntl.h>
   44 #include <sys/vnode.h>
   45 #include <sys/linker.h>
   46 
   47 #include <machine/elf.h>
   48 
   49 #include <vm/vm.h>
   50 #include <vm/vm_param.h>
   51 #include <vm/vm_object.h>
   52 #include <vm/vm_kern.h>
   53 #include <vm/vm_extern.h>
   54 #include <vm/pmap.h>
   55 #include <vm/vm_map.h>
   56 
   57 #include <sys/link_elf.h>
   58 
   59 #include "linker_if.h"
   60 
   61 typedef struct {
   62         void            *addr;
   63         Elf_Off         size;
   64         int             flags;
   65         int             sec;    /* Original section */
   66         char            *name;
   67 } Elf_progent;
   68 
   69 typedef struct {
   70         Elf_Rel         *rel;
   71         int             nrel;
   72         int             sec;
   73 } Elf_relent;
   74 
   75 typedef struct {
   76         Elf_Rela        *rela;
   77         int             nrela;
   78         int             sec;
   79 } Elf_relaent;
   80 
   81 
   82 typedef struct elf_file {
   83         struct linker_file lf;          /* Common fields */
   84 
   85         int             preloaded;
   86         caddr_t         address;        /* Relocation address */
   87         vm_object_t     object;         /* VM object to hold file pages */
   88         Elf_Shdr        *e_shdr;
   89 
   90         Elf_progent     *progtab;
   91         int             nprogtab;
   92 
   93         Elf_relaent     *relatab;
   94         int             nrela;
   95 
   96         Elf_relent      *reltab;
   97         int             nrel;
   98 
   99         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
  100         long            ddbsymcnt;      /* Number of symbols */
  101         caddr_t         ddbstrtab;      /* String table */
  102         long            ddbstrcnt;      /* number of bytes in string table */
  103 
  104         caddr_t         shstrtab;       /* Section name string table */
  105         long            shstrcnt;       /* number of bytes in string table */
  106 
  107 } *elf_file_t;
  108 
  109 static int      link_elf_link_preload(linker_class_t cls,
  110                     const char *, linker_file_t *);
  111 static int      link_elf_link_preload_finish(linker_file_t);
  112 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
  113 static int      link_elf_lookup_symbol(linker_file_t, const char *,
  114                     c_linker_sym_t *);
  115 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
  116                     linker_symval_t *);
  117 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
  118                     c_linker_sym_t *sym, long *diffp);
  119 
  120 static void     link_elf_unload_file(linker_file_t);
  121 static int      link_elf_lookup_set(linker_file_t, const char *,
  122                     void ***, void ***, int *);
  123 static int      link_elf_each_function_name(linker_file_t,
  124                     int (*)(const char *, void *), void *);
  125 static void     link_elf_reloc_local(linker_file_t);
  126 
  127 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Word symidx, int deps);
  128 
  129 static kobj_method_t link_elf_methods[] = {
  130         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
  131         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
  132         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
  133         KOBJMETHOD(linker_unload,               link_elf_unload_file),
  134         KOBJMETHOD(linker_load_file,            link_elf_load_file),
  135         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
  136         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
  137         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
  138         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
  139         { 0, 0 }
  140 };
  141 
  142 static struct linker_class link_elf_class = {
  143 #if ELF_TARG_CLASS == ELFCLASS32
  144         "elf32_obj",
  145 #else
  146         "elf64_obj",
  147 #endif
  148         link_elf_methods, sizeof(struct elf_file)
  149 };
  150 
  151 static int      relocate_file(elf_file_t ef);
  152 
  153 static void
  154 link_elf_error(const char *s)
  155 {
  156         printf("kldload: %s\n", s);
  157 }
  158 
  159 static void
  160 link_elf_init(void *arg)
  161 {
  162 
  163         linker_add_class(&link_elf_class);
  164 }
  165 
  166 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
  167 
  168 static int
  169 link_elf_link_preload(linker_class_t cls, const char *filename,
  170     linker_file_t *result)
  171 {
  172         Elf_Ehdr *hdr;
  173         Elf_Shdr *shdr;
  174         Elf_Sym *es;
  175         void *modptr, *baseptr, *sizeptr;
  176         char *type;
  177         elf_file_t ef;
  178         linker_file_t lf;
  179         Elf_Addr off;
  180         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
  181 
  182         /* Look to see if we have the file preloaded */
  183         modptr = preload_search_by_name(filename);
  184         if (modptr == NULL)
  185                 return ENOENT;
  186 
  187         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
  188         baseptr = preload_search_info(modptr, MODINFO_ADDR);
  189         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  190         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
  191             MODINFOMD_ELFHDR);
  192         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
  193             MODINFOMD_SHDR);
  194         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
  195             " obj module") != 0 &&
  196             strcmp(type, "elf obj module") != 0)) {
  197                 return (EFTYPE);
  198         }
  199         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
  200             shdr == NULL)
  201                 return (EINVAL);
  202 
  203         lf = linker_make_file(filename, &link_elf_class);
  204         if (lf == NULL)
  205                 return (ENOMEM);
  206 
  207         ef = (elf_file_t)lf;
  208         ef->preloaded = 1;
  209         ef->address = *(caddr_t *)baseptr;
  210         lf->address = *(caddr_t *)baseptr;
  211         lf->size = *(size_t *)sizeptr;
  212 
  213         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
  214             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
  215             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
  216             hdr->e_version != EV_CURRENT ||
  217             hdr->e_type != ET_REL ||
  218             hdr->e_machine != ELF_TARG_MACH) {
  219                 error = EFTYPE;
  220                 goto out;
  221         }
  222         ef->e_shdr = shdr;
  223 
  224         /* Scan the section header for information and table sizing. */
  225         symtabindex = -1;
  226         symstrindex = -1;
  227         for (i = 0; i < hdr->e_shnum; i++) {
  228                 switch (shdr[i].sh_type) {
  229                 case SHT_PROGBITS:
  230                 case SHT_NOBITS:
  231                         ef->nprogtab++;
  232                         break;
  233                 case SHT_SYMTAB:
  234                         symtabindex = i;
  235                         symstrindex = shdr[i].sh_link;
  236                         break;
  237                 case SHT_REL:
  238                         ef->nrel++;
  239                         break;
  240                 case SHT_RELA:
  241                         ef->nrela++;
  242                         break;
  243                 }
  244         }
  245 
  246         shstrindex = hdr->e_shstrndx;
  247         if (ef->nprogtab == 0 || symstrindex < 0 ||
  248             symstrindex >= hdr->e_shnum ||
  249             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
  250             shstrindex >= hdr->e_shnum ||
  251             shdr[shstrindex].sh_type != SHT_STRTAB) {
  252                 printf("%s: bad/missing section headers\n", filename);
  253                 error = ENOEXEC;
  254                 goto out;
  255         }
  256 
  257         /* Allocate space for tracking the load chunks */
  258         if (ef->nprogtab != 0)
  259                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  260                     M_LINKER, M_WAITOK | M_ZERO);
  261         if (ef->nrel != 0)
  262                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
  263                     M_WAITOK | M_ZERO);
  264         if (ef->nrela != 0)
  265                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
  266                     M_WAITOK | M_ZERO);
  267         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
  268             (ef->nrel != 0 && ef->reltab == NULL) ||
  269             (ef->nrela != 0 && ef->relatab == NULL)) {
  270                 error = ENOMEM;
  271                 goto out;
  272         }
  273 
  274         /* XXX, relocate the sh_addr fields saved by the loader. */
  275         off = 0;
  276         for (i = 0; i < hdr->e_shnum; i++) {
  277                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
  278                         off = shdr[i].sh_addr;
  279         }
  280         for (i = 0; i < hdr->e_shnum; i++) {
  281                 if (shdr[i].sh_addr != 0)
  282                         shdr[i].sh_addr = shdr[i].sh_addr - off +
  283                             (Elf_Addr)ef->address;
  284         }
  285 
  286         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  287         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
  288         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  289         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
  290         ef->shstrcnt = shdr[shstrindex].sh_size;
  291         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
  292 
  293         /* Now fill out progtab and the relocation tables. */
  294         pb = 0;
  295         rl = 0;
  296         ra = 0;
  297         for (i = 0; i < hdr->e_shnum; i++) {
  298                 switch (shdr[i].sh_type) {
  299                 case SHT_PROGBITS:
  300                 case SHT_NOBITS:
  301                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
  302                         if (shdr[i].sh_type == SHT_PROGBITS)
  303                                 ef->progtab[pb].name = "<<PROGBITS>>";
  304                         else
  305                                 ef->progtab[pb].name = "<<NOBITS>>";
  306                         ef->progtab[pb].size = shdr[i].sh_size;
  307                         ef->progtab[pb].sec = i;
  308                         if (ef->shstrtab && shdr[i].sh_name != 0)
  309                                 ef->progtab[pb].name =
  310                                     ef->shstrtab + shdr[i].sh_name;
  311 
  312                         /* Update all symbol values with the offset. */
  313                         for (j = 0; j < ef->ddbsymcnt; j++) {
  314                                 es = &ef->ddbsymtab[j];
  315                                 if (es->st_shndx != i)
  316                                         continue;
  317                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  318                         }
  319                         pb++;
  320                         break;
  321                 case SHT_REL:
  322                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
  323                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  324                         ef->reltab[rl].sec = shdr[i].sh_info;
  325                         rl++;
  326                         break;
  327                 case SHT_RELA:
  328                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
  329                         ef->relatab[ra].nrela =
  330                             shdr[i].sh_size / sizeof(Elf_Rela);
  331                         ef->relatab[ra].sec = shdr[i].sh_info;
  332                         ra++;
  333                         break;
  334                 }
  335         }
  336         if (pb != ef->nprogtab)
  337                 panic("lost progbits");
  338         if (rl != ef->nrel)
  339                 panic("lost rel");
  340         if (ra != ef->nrela)
  341                 panic("lost rela");
  342 
  343         /* Local intra-module relocations */
  344         link_elf_reloc_local(lf);
  345 
  346         *result = lf;
  347         return (0);
  348 
  349 out:
  350         /* preload not done this way */
  351         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  352         return (error);
  353 }
  354 
  355 static int
  356 link_elf_link_preload_finish(linker_file_t lf)
  357 {
  358         elf_file_t ef;
  359         int error;
  360 
  361         ef = (elf_file_t)lf;
  362         error = relocate_file(ef);
  363         if (error)
  364                 return error;
  365 
  366         /* Notify MD code that a module is being loaded. */
  367         error = elf_cpu_load_file(lf);
  368         if (error)
  369                 return (error);
  370 
  371         return (0);
  372 }
  373 
  374 static int
  375 link_elf_load_file(linker_class_t cls, const char *filename,
  376     linker_file_t *result)
  377 {
  378         struct nameidata nd;
  379         struct thread *td = curthread;  /* XXX */
  380         Elf_Ehdr *hdr;
  381         Elf_Shdr *shdr;
  382         Elf_Sym *es;
  383         int nbytes, i, j;
  384         vm_offset_t mapbase;
  385         size_t mapsize;
  386         int error = 0;
  387         int resid, flags;
  388         elf_file_t ef;
  389         linker_file_t lf;
  390         int symtabindex;
  391         int symstrindex;
  392         int shstrindex;
  393         int nsym;
  394         int pb, rl, ra;
  395         int alignmask;
  396 
  397         GIANT_REQUIRED;
  398 
  399         shdr = NULL;
  400         lf = NULL;
  401         mapsize = 0;
  402         hdr = NULL;
  403 
  404         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
  405         flags = FREAD;
  406         error = vn_open(&nd, &flags, 0, -1);
  407         if (error)
  408                 return error;
  409         NDFREE(&nd, NDF_ONLY_PNBUF);
  410 #ifdef MAC
  411         error = mac_check_kld_load(td->td_ucred, nd.ni_vp);
  412         if (error) {
  413                 goto out;
  414         }
  415 #endif
  416 
  417         /* Read the elf header from the file. */
  418         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
  419         if (hdr == NULL) {
  420                 error = ENOMEM;
  421                 goto out;
  422         }
  423         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
  424             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  425             &resid, td);
  426         if (error)
  427                 goto out;
  428         if (resid != 0){
  429                 error = ENOEXEC;
  430                 goto out;
  431         }
  432 
  433         if (!IS_ELF(*hdr)) {
  434                 error = ENOEXEC;
  435                 goto out;
  436         }
  437 
  438         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
  439             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
  440                 link_elf_error("Unsupported file layout");
  441                 error = ENOEXEC;
  442                 goto out;
  443         }
  444         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
  445             || hdr->e_version != EV_CURRENT) {
  446                 link_elf_error("Unsupported file version");
  447                 error = ENOEXEC;
  448                 goto out;
  449         }
  450         if (hdr->e_type != ET_REL) {
  451                 link_elf_error("Unsupported file type");
  452                 error = ENOEXEC;
  453                 goto out;
  454         }
  455         if (hdr->e_machine != ELF_TARG_MACH) {
  456                 link_elf_error("Unsupported machine");
  457                 error = ENOEXEC;
  458                 goto out;
  459         }
  460 
  461         lf = linker_make_file(filename, &link_elf_class);
  462         if (!lf) {
  463                 error = ENOMEM;
  464                 goto out;
  465         }
  466         ef = (elf_file_t) lf;
  467         ef->nprogtab = 0;
  468         ef->e_shdr = 0;
  469         ef->nrel = 0;
  470         ef->nrela = 0;
  471 
  472         /* Allocate and read in the section header */
  473         nbytes = hdr->e_shnum * hdr->e_shentsize;
  474         if (nbytes == 0 || hdr->e_shoff == 0 ||
  475             hdr->e_shentsize != sizeof(Elf_Shdr)) {
  476                 error = ENOEXEC;
  477                 goto out;
  478         }
  479         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
  480         if (shdr == NULL) {
  481                 error = ENOMEM;
  482                 goto out;
  483         }
  484         ef->e_shdr = shdr;
  485         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
  486             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
  487         if (error)
  488                 goto out;
  489         if (resid) {
  490                 error = ENOEXEC;
  491                 goto out;
  492         }
  493 
  494         /* Scan the section header for information and table sizing. */
  495         nsym = 0;
  496         symtabindex = -1;
  497         symstrindex = -1;
  498         for (i = 0; i < hdr->e_shnum; i++) {
  499                 switch (shdr[i].sh_type) {
  500                 case SHT_PROGBITS:
  501                 case SHT_NOBITS:
  502                         ef->nprogtab++;
  503                         break;
  504                 case SHT_SYMTAB:
  505                         nsym++;
  506                         symtabindex = i;
  507                         symstrindex = shdr[i].sh_link;
  508                         break;
  509                 case SHT_REL:
  510                         ef->nrel++;
  511                         break;
  512                 case SHT_RELA:
  513                         ef->nrela++;
  514                         break;
  515                 case SHT_STRTAB:
  516                         break;
  517                 }
  518         }
  519         if (ef->nprogtab == 0) {
  520                 link_elf_error("file has no contents");
  521                 error = ENOEXEC;
  522                 goto out;
  523         }
  524         if (nsym != 1) {
  525                 /* Only allow one symbol table for now */
  526                 link_elf_error("file has no valid symbol table");
  527                 error = ENOEXEC;
  528                 goto out;
  529         }
  530         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
  531             shdr[symstrindex].sh_type != SHT_STRTAB) {
  532                 link_elf_error("file has invalid symbol strings");
  533                 error = ENOEXEC;
  534                 goto out;
  535         }
  536 
  537         /* Allocate space for tracking the load chunks */
  538         if (ef->nprogtab != 0)
  539                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
  540                     M_LINKER, M_WAITOK | M_ZERO);
  541         if (ef->nrel != 0)
  542                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
  543                     M_WAITOK | M_ZERO);
  544         if (ef->nrela != 0)
  545                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
  546                     M_WAITOK | M_ZERO);
  547         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
  548             (ef->nrel != 0 && ef->reltab == NULL) ||
  549             (ef->nrela != 0 && ef->relatab == NULL)) {
  550                 error = ENOMEM;
  551                 goto out;
  552         }
  553 
  554         if (symtabindex == -1)
  555                 panic("lost symbol table index");
  556         /* Allocate space for and load the symbol table */
  557         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
  558         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
  559         if (ef->ddbsymtab == NULL) {
  560                 error = ENOMEM;
  561                 goto out;
  562         }
  563         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
  564             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
  565             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  566             &resid, td);
  567         if (error)
  568                 goto out;
  569         if (resid != 0){
  570                 error = EINVAL;
  571                 goto out;
  572         }
  573 
  574         if (symstrindex == -1)
  575                 panic("lost symbol string index");
  576         /* Allocate space for and load the symbol strings */
  577         ef->ddbstrcnt = shdr[symstrindex].sh_size;
  578         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
  579         if (ef->ddbstrtab == NULL) {
  580                 error = ENOMEM;
  581                 goto out;
  582         }
  583         error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
  584             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
  585             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  586             &resid, td);
  587         if (error)
  588                 goto out;
  589         if (resid != 0){
  590                 error = EINVAL;
  591                 goto out;
  592         }
  593 
  594         /* Do we have a string table for the section names?  */
  595         shstrindex = -1;
  596         if (hdr->e_shstrndx != 0 &&
  597             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
  598                 shstrindex = hdr->e_shstrndx;
  599                 ef->shstrcnt = shdr[shstrindex].sh_size;
  600                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
  601                     M_WAITOK);
  602                 if (ef->shstrtab == NULL) {
  603                         error = ENOMEM;
  604                         goto out;
  605                 }
  606                 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
  607                     shdr[shstrindex].sh_size, shdr[shstrindex].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 
  618         /* Size up code/data(progbits) and bss(nobits). */
  619         alignmask = 0;
  620         for (i = 0; i < hdr->e_shnum; i++) {
  621                 switch (shdr[i].sh_type) {
  622                 case SHT_PROGBITS:
  623                 case SHT_NOBITS:
  624                         alignmask = shdr[i].sh_addralign - 1;
  625                         mapsize += alignmask;
  626                         mapsize &= ~alignmask;
  627                         mapsize += shdr[i].sh_size;
  628                         break;
  629                 }
  630         }
  631 
  632         /*
  633          * We know how much space we need for the text/data/bss/etc.
  634          * This stuff needs to be in a single chunk so that profiling etc
  635          * can get the bounds and gdb can associate offsets with modules
  636          */
  637         ef->object = vm_object_allocate(OBJT_DEFAULT,
  638             round_page(mapsize) >> PAGE_SHIFT);
  639         if (ef->object == NULL) {
  640                 error = ENOMEM;
  641                 goto out;
  642         }
  643         ef->address = (caddr_t) vm_map_min(kernel_map);
  644         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
  645             round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE);
  646         if (error) {
  647                 vm_object_deallocate(ef->object);
  648                 ef->object = 0;
  649                 goto out;
  650         }
  651 
  652         /* Wire the pages */
  653         error = vm_map_wire(kernel_map, mapbase,
  654             mapbase + round_page(mapsize),
  655             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  656         if (error != KERN_SUCCESS) {
  657                 error = ENOMEM;
  658                 goto out;
  659         }
  660 
  661         /* Inform the kld system about the situation */
  662         lf->address = ef->address = (caddr_t)mapbase;
  663         lf->size = mapsize;
  664 
  665         /*
  666          * Now load code/data(progbits), zero bss(nobits), allocate space for
  667          * and load relocs
  668          */
  669         pb = 0;
  670         rl = 0;
  671         ra = 0;
  672         alignmask = 0;
  673         for (i = 0; i < hdr->e_shnum; i++) {
  674                 switch (shdr[i].sh_type) {
  675                 case SHT_PROGBITS:
  676                 case SHT_NOBITS:
  677                         alignmask = shdr[i].sh_addralign - 1;
  678                         mapbase += alignmask;
  679                         mapbase &= ~alignmask;
  680                         ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
  681                         if (shdr[i].sh_type == SHT_PROGBITS) {
  682                                 ef->progtab[pb].name = "<<PROGBITS>>";
  683                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
  684                                     ef->progtab[pb].addr,
  685                                     shdr[i].sh_size, shdr[i].sh_offset,
  686                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  687                                     NOCRED, &resid, td);
  688                                 if (error)
  689                                         goto out;
  690                                 if (resid != 0){
  691                                         error = EINVAL;
  692                                         goto out;
  693                                 }
  694                         } else {
  695                                 ef->progtab[pb].name = "<<NOBITS>>";
  696                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
  697                         }
  698                         ef->progtab[pb].size = shdr[i].sh_size;
  699                         ef->progtab[pb].sec = i;
  700                         if (ef->shstrtab && shdr[i].sh_name != 0)
  701                                 ef->progtab[pb].name =
  702                                     ef->shstrtab + shdr[i].sh_name;
  703 
  704                         /* Update all symbol values with the offset. */
  705                         for (j = 0; j < ef->ddbsymcnt; j++) {
  706                                 es = &ef->ddbsymtab[j];
  707                                 if (es->st_shndx != i)
  708                                         continue;
  709                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
  710                         }
  711                         mapbase += shdr[i].sh_size;
  712                         pb++;
  713                         break;
  714                 case SHT_REL:
  715                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
  716                             M_WAITOK);
  717                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
  718                         ef->reltab[rl].sec = shdr[i].sh_info;
  719                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  720                             (void *)ef->reltab[rl].rel,
  721                             shdr[i].sh_size, shdr[i].sh_offset,
  722                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  723                             &resid, td);
  724                         if (error)
  725                                 goto out;
  726                         if (resid != 0){
  727                                 error = EINVAL;
  728                                 goto out;
  729                         }
  730                         rl++;
  731                         break;
  732                 case SHT_RELA:
  733                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
  734                             M_WAITOK);
  735                         ef->relatab[ra].nrela =
  736                             shdr[i].sh_size / sizeof(Elf_Rela);
  737                         ef->relatab[ra].sec = shdr[i].sh_info;
  738                         error = vn_rdwr(UIO_READ, nd.ni_vp,
  739                             (void *)ef->relatab[ra].rela,
  740                             shdr[i].sh_size, shdr[i].sh_offset,
  741                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  742                             &resid, td);
  743                         if (error)
  744                                 goto out;
  745                         if (resid != 0){
  746                                 error = EINVAL;
  747                                 goto out;
  748                         }
  749                         ra++;
  750                         break;
  751                 }
  752         }
  753         if (pb != ef->nprogtab)
  754                 panic("lost progbits");
  755         if (rl != ef->nrel)
  756                 panic("lost rel");
  757         if (ra != ef->nrela)
  758                 panic("lost rela");
  759         if (mapbase != (vm_offset_t)ef->address + mapsize)
  760                 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
  761                     mapbase, ef->address, mapsize,
  762                     (vm_offset_t)ef->address + mapsize);
  763 
  764         /* Local intra-module relocations */
  765         link_elf_reloc_local(lf);
  766 
  767         /* Pull in dependencies */
  768         error = linker_load_dependencies(lf);
  769         if (error)
  770                 goto out;
  771 
  772         /* External relocations */
  773         error = relocate_file(ef);
  774         if (error)
  775                 goto out;
  776 
  777         /* Notify MD code that a module is being loaded. */
  778         error = elf_cpu_load_file(lf);
  779         if (error)
  780                 goto out;
  781 
  782         *result = lf;
  783 
  784 out:
  785         if (error && lf)
  786                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  787         if (hdr)
  788                 free(hdr, M_LINKER);
  789         VOP_UNLOCK(nd.ni_vp, 0, td);
  790         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  791 
  792         return error;
  793 }
  794 
  795 static void
  796 link_elf_unload_file(linker_file_t file)
  797 {
  798         elf_file_t ef = (elf_file_t) file;
  799         int i;
  800 
  801         /* Notify MD code that a module is being unloaded. */
  802         elf_cpu_unload_file(file);
  803 
  804         if (ef->preloaded) {
  805                 if (ef->reltab)
  806                         free(ef->reltab, M_LINKER);
  807                 if (ef->relatab)
  808                         free(ef->relatab, M_LINKER);
  809                 if (ef->progtab)
  810                         free(ef->progtab, M_LINKER);
  811                 if (file->filename != NULL)
  812                         preload_delete_name(file->filename);
  813                 /* XXX reclaim module memory? */
  814                 return;
  815         }
  816 
  817         for (i = 0; i < ef->nrel; i++)
  818                 if (ef->reltab[i].rel)
  819                         free(ef->reltab[i].rel, M_LINKER);
  820         for (i = 0; i < ef->nrela; i++)
  821                 if (ef->relatab[i].rela)
  822                         free(ef->relatab[i].rela, M_LINKER);
  823         if (ef->reltab)
  824                 free(ef->reltab, M_LINKER);
  825         if (ef->relatab)
  826                 free(ef->relatab, M_LINKER);
  827         if (ef->progtab)
  828                 free(ef->progtab, M_LINKER);
  829 
  830         if (ef->object) {
  831                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
  832                     (vm_offset_t) ef->address +
  833                     (ef->object->size << PAGE_SHIFT));
  834         }
  835         if (ef->e_shdr)
  836                 free(ef->e_shdr, M_LINKER);
  837         if (ef->ddbsymtab)
  838                 free(ef->ddbsymtab, M_LINKER);
  839         if (ef->ddbstrtab)
  840                 free(ef->ddbstrtab, M_LINKER);
  841         if (ef->shstrtab)
  842                 free(ef->shstrtab, M_LINKER);
  843 }
  844 
  845 static const char *
  846 symbol_name(elf_file_t ef, Elf_Word r_info)
  847 {
  848         const Elf_Sym *ref;
  849 
  850         if (ELF_R_SYM(r_info)) {
  851                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
  852                 return ef->ddbstrtab + ref->st_name;
  853         } else
  854                 return NULL;
  855 }
  856 
  857 static Elf_Addr
  858 findbase(elf_file_t ef, int sec)
  859 {
  860         int i;
  861         Elf_Addr base = 0;
  862 
  863         for (i = 0; i < ef->nprogtab; i++) {
  864                 if (sec == ef->progtab[i].sec) {
  865                         base = (Elf_Addr)ef->progtab[i].addr;
  866                         break;
  867                 }
  868         }
  869         return base;
  870 }
  871 
  872 static int
  873 relocate_file(elf_file_t ef)
  874 {
  875         const Elf_Rel *rellim;
  876         const Elf_Rel *rel;
  877         const Elf_Rela *relalim;
  878         const Elf_Rela *rela;
  879         const char *symname;
  880         const Elf_Sym *sym;
  881         int i;
  882         Elf_Word symidx;
  883         Elf_Addr base;
  884 
  885 
  886         /* Perform relocations without addend if there are any: */
  887         for (i = 0; i < ef->nrel; i++) {
  888                 rel = ef->reltab[i].rel;
  889                 if (rel == NULL)
  890                         panic("lost a reltab!");
  891                 rellim = rel + ef->reltab[i].nrel;
  892                 base = findbase(ef, ef->reltab[i].sec);
  893                 if (base == 0)
  894                         panic("lost base for reltab");
  895                 for ( ; rel < rellim; rel++) {
  896                         symidx = ELF_R_SYM(rel->r_info);
  897                         if (symidx >= ef->ddbsymcnt)
  898                                 continue;
  899                         sym = ef->ddbsymtab + symidx;
  900                         /* Local relocs are already done */
  901                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
  902                                 continue;
  903                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
  904                             elf_obj_lookup)) {
  905                                 symname = symbol_name(ef, rel->r_info);
  906                                 printf("link_elf_obj: symbol %s undefined\n",
  907                                     symname);
  908                                 return ENOENT;
  909                         }
  910                 }
  911         }
  912 
  913         /* Perform relocations with addend if there are any: */
  914         for (i = 0; i < ef->nrela; i++) {
  915                 rela = ef->relatab[i].rela;
  916                 if (rela == NULL)
  917                         panic("lost a relatab!");
  918                 relalim = rela + ef->relatab[i].nrela;
  919                 base = findbase(ef, ef->relatab[i].sec);
  920                 if (base == 0)
  921                         panic("lost base for relatab");
  922                 for ( ; rela < relalim; rela++) {
  923                         symidx = ELF_R_SYM(rela->r_info);
  924                         if (symidx >= ef->ddbsymcnt)
  925                                 continue;
  926                         sym = ef->ddbsymtab + symidx;
  927                         /* Local relocs are already done */
  928                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
  929                                 continue;
  930                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
  931                             elf_obj_lookup)) {
  932                                 symname = symbol_name(ef, rela->r_info);
  933                                 printf("link_elf_obj: symbol %s undefined\n",
  934                                     symname);
  935                                 return ENOENT;
  936                         }
  937                 }
  938         }
  939 
  940         return 0;
  941 }
  942 
  943 static int
  944 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
  945 {
  946         elf_file_t ef = (elf_file_t) lf;
  947         const Elf_Sym *symp;
  948         const char *strp;
  949         int i;
  950 
  951         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
  952                 strp = ef->ddbstrtab + symp->st_name;
  953                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
  954                         *sym = (c_linker_sym_t) symp;
  955                         return 0;
  956                 }
  957         }
  958         return ENOENT;
  959 }
  960 
  961 static int
  962 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
  963     linker_symval_t *symval)
  964 {
  965         elf_file_t ef = (elf_file_t) lf;
  966         const Elf_Sym *es = (const Elf_Sym*) sym;
  967 
  968         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
  969                 symval->name = ef->ddbstrtab + es->st_name;
  970                 symval->value = (caddr_t)es->st_value;
  971                 symval->size = es->st_size;
  972                 return 0;
  973         }
  974         return ENOENT;
  975 }
  976 
  977 static int
  978 link_elf_search_symbol(linker_file_t lf, caddr_t value,
  979     c_linker_sym_t *sym, long *diffp)
  980 {
  981         elf_file_t ef = (elf_file_t) lf;
  982         u_long off = (uintptr_t) (void *) value;
  983         u_long diff = off;
  984         u_long st_value;
  985         const Elf_Sym *es;
  986         const Elf_Sym *best = 0;
  987         int i;
  988 
  989         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
  990                 if (es->st_name == 0)
  991                         continue;
  992                 st_value = es->st_value;
  993                 if (off >= st_value) {
  994                         if (off - st_value < diff) {
  995                                 diff = off - st_value;
  996                                 best = es;
  997                                 if (diff == 0)
  998                                         break;
  999                         } else if (off - st_value == diff) {
 1000                                 best = es;
 1001                         }
 1002                 }
 1003         }
 1004         if (best == 0)
 1005                 *diffp = off;
 1006         else
 1007                 *diffp = diff;
 1008         *sym = (c_linker_sym_t) best;
 1009 
 1010         return 0;
 1011 }
 1012 
 1013 /*
 1014  * Look up a linker set on an ELF system.
 1015  */
 1016 static int
 1017 link_elf_lookup_set(linker_file_t lf, const char *name,
 1018     void ***startp, void ***stopp, int *countp)
 1019 {
 1020         elf_file_t ef = (elf_file_t)lf;
 1021         void **start, **stop;
 1022         int i, count;
 1023 
 1024         /* Relative to section number */
 1025         for (i = 0; i < ef->nprogtab; i++) {
 1026                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
 1027                     strcmp(ef->progtab[i].name + 4, name) == 0) {
 1028                         start  = (void **)ef->progtab[i].addr;
 1029                         stop = (void **)((char *)ef->progtab[i].addr +
 1030                             ef->progtab[i].size);
 1031                         count = stop - start;
 1032                         if (startp)
 1033                                 *startp = start;
 1034                         if (stopp)
 1035                                 *stopp = stop;
 1036                         if (countp)
 1037                                 *countp = count;
 1038                         return (0);
 1039                 }
 1040         }
 1041         return (ESRCH);
 1042 }
 1043 
 1044 static int
 1045 link_elf_each_function_name(linker_file_t file,
 1046     int (*callback)(const char *, void *), void *opaque)
 1047 {
 1048         elf_file_t ef = (elf_file_t)file;
 1049         const Elf_Sym *symp;
 1050         int i, error;
 1051         
 1052         /* Exhaustive search */
 1053         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1054                 if (symp->st_value != 0 &&
 1055                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1056                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
 1057                         if (error)
 1058                                 return (error);
 1059                 }
 1060         }
 1061         return (0);
 1062 }
 1063 
 1064 /*
 1065  * Symbol lookup function that can be used when the symbol index is known (ie
 1066  * in relocations). It uses the symbol index instead of doing a fully fledged
 1067  * hash table based lookup when such is valid. For example for local symbols.
 1068  * This is not only more efficient, it's also more correct. It's not always
 1069  * the case that the symbol can be found through the hash table.
 1070  */
 1071 static Elf_Addr
 1072 elf_obj_lookup(linker_file_t lf, Elf_Word symidx, int deps)
 1073 {
 1074         elf_file_t ef = (elf_file_t)lf;
 1075         const Elf_Sym *sym;
 1076         const char *symbol;
 1077         Elf_Addr ret;
 1078 
 1079         /* Don't even try to lookup the symbol if the index is bogus. */
 1080         if (symidx >= ef->ddbsymcnt)
 1081                 return (0);
 1082 
 1083         sym = ef->ddbsymtab + symidx;
 1084 
 1085         /* Quick answer if there is a definition included. */
 1086         if (sym->st_shndx != SHN_UNDEF)
 1087                 return (sym->st_value);
 1088 
 1089         /* If we get here, then it is undefined and needs a lookup. */
 1090         switch (ELF_ST_BIND(sym->st_info)) {
 1091         case STB_LOCAL:
 1092                 /* Local, but undefined? huh? */
 1093                 return (0);
 1094 
 1095         case STB_GLOBAL:
 1096                 /* Relative to Data or Function name */
 1097                 symbol = ef->ddbstrtab + sym->st_name;
 1098 
 1099                 /* Force a lookup failure if the symbol name is bogus. */
 1100                 if (*symbol == 0)
 1101                         return (0);
 1102                 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
 1103                 return ret;
 1104 
 1105         case STB_WEAK:
 1106                 printf("link_elf_obj: Weak symbols not supported\n");
 1107                 return (0);
 1108 
 1109         default:
 1110                 return (0);
 1111         }
 1112 }
 1113 
 1114 static void
 1115 link_elf_reloc_local(linker_file_t lf)
 1116 {
 1117         elf_file_t ef = (elf_file_t)lf;
 1118         const Elf_Rel *rellim;
 1119         const Elf_Rel *rel;
 1120         const Elf_Rela *relalim;
 1121         const Elf_Rela *rela;
 1122         const Elf_Sym *sym;
 1123         Elf_Addr base;
 1124         int i;
 1125         Elf_Word symidx;
 1126 
 1127         /* Perform relocations without addend if there are any: */
 1128         for (i = 0; i < ef->nrel; i++) {
 1129                 rel = ef->reltab[i].rel;
 1130                 if (rel == NULL)
 1131                         panic("lost a reltab!");
 1132                 rellim = rel + ef->reltab[i].nrel;
 1133                 base = findbase(ef, ef->reltab[i].sec);
 1134                 if (base == 0)
 1135                         panic("lost base for reltab");
 1136                 for ( ; rel < rellim; rel++) {
 1137                         symidx = ELF_R_SYM(rel->r_info);
 1138                         if (symidx >= ef->ddbsymcnt)
 1139                                 continue;
 1140                         sym = ef->ddbsymtab + symidx;
 1141                         /* Only do local relocs */
 1142                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1143                                 continue;
 1144                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
 1145                             elf_obj_lookup);
 1146                 }
 1147         }
 1148 
 1149         /* Perform relocations with addend if there are any: */
 1150         for (i = 0; i < ef->nrela; i++) {
 1151                 rela = ef->relatab[i].rela;
 1152                 if (rela == NULL)
 1153                         panic("lost a relatab!");
 1154                 relalim = rela + ef->relatab[i].nrela;
 1155                 base = findbase(ef, ef->relatab[i].sec);
 1156                 if (base == 0)
 1157                         panic("lost base for relatab");
 1158                 for ( ; rela < relalim; rela++) {
 1159                         symidx = ELF_R_SYM(rela->r_info);
 1160                         if (symidx >= ef->ddbsymcnt)
 1161                                 continue;
 1162                         sym = ef->ddbsymtab + symidx;
 1163                         /* Only do local relocs */
 1164                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
 1165                                 continue;
 1166                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
 1167                             elf_obj_lookup);
 1168                 }
 1169         }
 1170 }

Cache object: 3bc9d24cc1e3069949bd1ca9caf0d50f


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