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.c

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    1 /*-
    2  * Copyright (c) 1998-2000 Doug Rabson
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD$");
   29 
   30 #include "opt_ddb.h"
   31 #include "opt_gdb.h"
   32 #include "opt_mac.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #ifdef GPROF
   37 #include <sys/gmon.h>
   38 #endif
   39 #include <sys/kernel.h>
   40 #include <sys/lock.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mutex.h>
   43 #include <sys/mount.h>
   44 #include <sys/proc.h>
   45 #include <sys/namei.h>
   46 #include <sys/fcntl.h>
   47 #include <sys/vnode.h>
   48 #include <sys/linker.h>
   49 
   50 #include <machine/elf.h>
   51 
   52 #include <security/mac/mac_framework.h>
   53 
   54 #include <vm/vm.h>
   55 #include <vm/vm_param.h>
   56 #ifdef SPARSE_MAPPING
   57 #include <vm/vm_object.h>
   58 #include <vm/vm_kern.h>
   59 #include <vm/vm_extern.h>
   60 #endif
   61 #include <vm/pmap.h>
   62 #include <vm/vm_map.h>
   63 
   64 #include <sys/link_elf.h>
   65 
   66 #ifdef DDB_CTF
   67 #include <net/zlib.h>
   68 #endif
   69 
   70 #include "linker_if.h"
   71 
   72 #define MAXSEGS 4
   73 
   74 typedef struct elf_file {
   75     struct linker_file  lf;             /* Common fields */
   76     int                 preloaded;      /* Was file pre-loaded */
   77     caddr_t             address;        /* Relocation address */
   78 #ifdef SPARSE_MAPPING
   79     vm_object_t         object;         /* VM object to hold file pages */
   80 #endif
   81     Elf_Dyn*            dynamic;        /* Symbol table etc. */
   82     Elf_Hashelt         nbuckets;       /* DT_HASH info */
   83     Elf_Hashelt         nchains;
   84     const Elf_Hashelt*  buckets;
   85     const Elf_Hashelt*  chains;
   86     caddr_t             hash;
   87     caddr_t             strtab;         /* DT_STRTAB */
   88     int                 strsz;          /* DT_STRSZ */
   89     const Elf_Sym*      symtab;         /* DT_SYMTAB */
   90     Elf_Addr*           got;            /* DT_PLTGOT */
   91     const Elf_Rel*      pltrel;         /* DT_JMPREL */
   92     int                 pltrelsize;     /* DT_PLTRELSZ */
   93     const Elf_Rela*     pltrela;        /* DT_JMPREL */
   94     int                 pltrelasize;    /* DT_PLTRELSZ */
   95     const Elf_Rel*      rel;            /* DT_REL */
   96     int                 relsize;        /* DT_RELSZ */
   97     const Elf_Rela*     rela;           /* DT_RELA */
   98     int                 relasize;       /* DT_RELASZ */
   99     caddr_t             modptr;
  100     const Elf_Sym*      ddbsymtab;      /* The symbol table we are using */
  101     long                ddbsymcnt;      /* Number of symbols */
  102     caddr_t             ddbstrtab;      /* String table */
  103     long                ddbstrcnt;      /* number of bytes in string table */
  104     caddr_t             symbase;        /* malloc'ed symbold base */
  105     caddr_t             strbase;        /* malloc'ed string base */
  106     caddr_t             ctftab;         /* CTF table */
  107     long                ctfcnt;         /* number of bytes in CTF table */
  108     caddr_t             ctfoff;         /* CTF offset table */
  109     caddr_t             typoff;         /* Type offset table */
  110     long                typlen;         /* Number of type entries. */
  111 #ifdef GDB
  112     struct link_map     gdb;            /* hooks for gdb */
  113 #endif
  114 } *elf_file_t;
  115 
  116 #include <kern/kern_ctf.c>
  117 
  118 static int      link_elf_link_common_finish(linker_file_t);
  119 static int      link_elf_link_preload(linker_class_t cls,
  120                                       const char*, linker_file_t*);
  121 static int      link_elf_link_preload_finish(linker_file_t);
  122 static int      link_elf_load_file(linker_class_t, const char*, linker_file_t*);
  123 static int      link_elf_lookup_symbol(linker_file_t, const char*,
  124                                        c_linker_sym_t*);
  125 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
  126 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
  127                                        c_linker_sym_t* sym, long* diffp);
  128 
  129 static void     link_elf_unload_file(linker_file_t);
  130 static void     link_elf_unload_preload(linker_file_t);
  131 static int      link_elf_lookup_set(linker_file_t, const char *,
  132                                     void ***, void ***, int *);
  133 static int      link_elf_each_function_name(linker_file_t,
  134                                 int (*)(const char *, void *),
  135                                 void *);
  136 static int      link_elf_each_function_nameval(linker_file_t,
  137                                 linker_function_nameval_callback_t,
  138                                 void *);
  139 static void     link_elf_reloc_local(linker_file_t);
  140 static Elf_Addr elf_lookup(linker_file_t lf, Elf_Size symidx, int deps);
  141 
  142 static kobj_method_t link_elf_methods[] = {
  143     KOBJMETHOD(linker_lookup_symbol,    link_elf_lookup_symbol),
  144     KOBJMETHOD(linker_symbol_values,    link_elf_symbol_values),
  145     KOBJMETHOD(linker_search_symbol,    link_elf_search_symbol),
  146     KOBJMETHOD(linker_unload,           link_elf_unload_file),
  147     KOBJMETHOD(linker_load_file,        link_elf_load_file),
  148     KOBJMETHOD(linker_link_preload,     link_elf_link_preload),
  149     KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
  150     KOBJMETHOD(linker_lookup_set,       link_elf_lookup_set),
  151     KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
  152     KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
  153     KOBJMETHOD(linker_ctf_get,          link_elf_ctf_get),
  154     { 0, 0 }
  155 };
  156 
  157 static struct linker_class link_elf_class = {
  158 #if ELF_TARG_CLASS == ELFCLASS32
  159     "elf32",
  160 #else
  161     "elf64",
  162 #endif
  163     link_elf_methods, sizeof(struct elf_file)
  164 };
  165 
  166 static int              parse_dynamic(elf_file_t ef);
  167 static int              relocate_file(elf_file_t ef);
  168 static int              link_elf_preload_parse_symbols(elf_file_t ef);
  169 
  170 #ifdef GDB
  171 static void             r_debug_state(struct r_debug *dummy_one,
  172                                       struct link_map *dummy_two);
  173 
  174 /*
  175  * A list of loaded modules for GDB to use for loading symbols.
  176  */
  177 struct r_debug r_debug;
  178 
  179 #define GDB_STATE(s)    r_debug.r_state = s; r_debug_state(NULL, NULL);
  180 
  181 /*
  182  * Function for the debugger to set a breakpoint on to gain control.
  183  */
  184 static void
  185 r_debug_state(struct r_debug *dummy_one __unused,
  186               struct link_map *dummy_two __unused)
  187 {
  188 }
  189 
  190 static void
  191 link_elf_add_gdb(struct link_map *l)
  192 {
  193     struct link_map *prev;
  194 
  195     l->l_next = NULL;
  196 
  197     if (r_debug.r_map == NULL) {
  198         /* Add first. */
  199         l->l_prev = NULL;
  200         r_debug.r_map = l;
  201     } else {
  202         /* Append to list. */
  203         for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
  204             ;
  205         l->l_prev = prev;
  206         prev->l_next = l;
  207     }
  208 }
  209 
  210 static void
  211 link_elf_delete_gdb(struct link_map *l)
  212 {
  213     if (l->l_prev == NULL) {
  214         /* Remove first. */
  215         if ((r_debug.r_map = l->l_next) != NULL)
  216             l->l_next->l_prev = NULL;
  217     } else {
  218         /* Remove any but first. */
  219         if ((l->l_prev->l_next = l->l_next) != NULL)
  220             l->l_next->l_prev = l->l_prev;
  221     }
  222 }
  223 #endif /* GDB */
  224 
  225 #ifdef __ia64__
  226 Elf_Addr link_elf_get_gp(linker_file_t);
  227 #endif
  228 
  229 /*
  230  * The kernel symbol table starts here.
  231  */
  232 extern struct _dynamic _DYNAMIC;
  233 
  234 static void
  235 link_elf_error(const char *filename, const char *s)
  236 {
  237         if (filename == NULL)
  238                 printf("kldload: %s\n", s);
  239         else
  240                 printf("kldload: %s: %s\n", filename, s);
  241 }
  242 
  243 /*
  244  * Actions performed after linking/loading both the preloaded kernel and any
  245  * modules; whether preloaded or dynamicly loaded.
  246  */
  247 static int
  248 link_elf_link_common_finish(linker_file_t lf)
  249 {
  250 #ifdef GDB
  251     elf_file_t ef = (elf_file_t)lf;
  252     char *newfilename;
  253 #endif
  254     int error;
  255 
  256     /* Notify MD code that a module is being loaded. */
  257     error = elf_cpu_load_file(lf);
  258     if (error)
  259         return (error);
  260 
  261 #ifdef GDB
  262     GDB_STATE(RT_ADD);
  263     ef->gdb.l_addr = lf->address;
  264     newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
  265     strcpy(newfilename, lf->filename);
  266     ef->gdb.l_name = newfilename;
  267     ef->gdb.l_ld = ef->dynamic;
  268     link_elf_add_gdb(&ef->gdb);
  269     GDB_STATE(RT_CONSISTENT);
  270 #endif
  271 
  272     return (0);
  273 }
  274 
  275 static void
  276 link_elf_init(void* arg)
  277 {
  278     Elf_Dyn     *dp;
  279     caddr_t     modptr, baseptr, sizeptr;
  280     elf_file_t  ef;
  281     char        *modname;
  282 
  283     linker_add_class(&link_elf_class);
  284 
  285     dp = (Elf_Dyn*) &_DYNAMIC;
  286     modname = NULL;
  287     modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
  288     if (modptr == NULL)
  289         modptr = preload_search_by_type("elf kernel");
  290     if (modptr)
  291         modname = (char *)preload_search_info(modptr, MODINFO_NAME);
  292     if (modname == NULL)
  293         modname = "kernel";
  294     linker_kernel_file = linker_make_file(modname, &link_elf_class);
  295     if (linker_kernel_file == NULL)
  296         panic("link_elf_init: Can't create linker structures for kernel");
  297 
  298     ef = (elf_file_t) linker_kernel_file;
  299     ef->preloaded = 1;
  300     ef->address = 0;
  301 #ifdef SPARSE_MAPPING
  302     ef->object = 0;
  303 #endif
  304     ef->dynamic = dp;
  305 
  306     if (dp)
  307         parse_dynamic(ef);
  308     linker_kernel_file->address = (caddr_t) KERNBASE;
  309     linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
  310 
  311     if (modptr) {
  312         ef->modptr = modptr;
  313         baseptr = preload_search_info(modptr, MODINFO_ADDR);
  314         if (baseptr)
  315             linker_kernel_file->address = *(caddr_t *)baseptr;
  316         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  317         if (sizeptr)
  318             linker_kernel_file->size = *(size_t *)sizeptr;
  319     }
  320     (void)link_elf_preload_parse_symbols(ef);
  321 
  322 #ifdef GDB
  323     r_debug.r_map = NULL;
  324     r_debug.r_brk = r_debug_state;
  325     r_debug.r_state = RT_CONSISTENT;
  326 #endif
  327 
  328     (void)link_elf_link_common_finish(linker_kernel_file);
  329     linker_kernel_file->flags |= LINKER_FILE_LINKED;
  330 }
  331 
  332 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
  333 
  334 static int
  335 link_elf_preload_parse_symbols(elf_file_t ef)
  336 {
  337     caddr_t     pointer;
  338     caddr_t     ssym, esym, base;
  339     caddr_t     strtab;
  340     int         strcnt;
  341     Elf_Sym*    symtab;
  342     int         symcnt;
  343 
  344     if (ef->modptr == NULL)
  345         return 0;
  346     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
  347     if (pointer == NULL)
  348         return 0;
  349     ssym = *(caddr_t *)pointer;
  350     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
  351     if (pointer == NULL)
  352         return 0;
  353     esym = *(caddr_t *)pointer;
  354 
  355     base = ssym;
  356 
  357     symcnt = *(long *)base;
  358     base += sizeof(long);
  359     symtab = (Elf_Sym *)base;
  360     base += roundup(symcnt, sizeof(long));
  361 
  362     if (base > esym || base < ssym) {
  363         printf("Symbols are corrupt!\n");
  364         return EINVAL;
  365     }
  366 
  367     strcnt = *(long *)base;
  368     base += sizeof(long);
  369     strtab = base;
  370     base += roundup(strcnt, sizeof(long));
  371 
  372     if (base > esym || base < ssym) {
  373         printf("Symbols are corrupt!\n");
  374         return EINVAL;
  375     }
  376 
  377     ef->ddbsymtab = symtab;
  378     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
  379     ef->ddbstrtab = strtab;
  380     ef->ddbstrcnt = strcnt;
  381 
  382     return 0;
  383 }
  384 
  385 static int
  386 parse_dynamic(elf_file_t ef)
  387 {
  388     Elf_Dyn *dp;
  389     int plttype = DT_REL;
  390 
  391     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  392         switch (dp->d_tag) {
  393         case DT_HASH:
  394         {
  395             /* From src/libexec/rtld-elf/rtld.c */
  396             const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
  397                 (ef->address + dp->d_un.d_ptr);
  398             ef->nbuckets = hashtab[0];
  399             ef->nchains = hashtab[1];
  400             ef->buckets = hashtab + 2;
  401             ef->chains = ef->buckets + ef->nbuckets;
  402             break;
  403         }
  404         case DT_STRTAB:
  405             ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
  406             break;
  407         case DT_STRSZ:
  408             ef->strsz = dp->d_un.d_val;
  409             break;
  410         case DT_SYMTAB:
  411             ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
  412             break;
  413         case DT_SYMENT:
  414             if (dp->d_un.d_val != sizeof(Elf_Sym))
  415                 return ENOEXEC;
  416             break;
  417         case DT_PLTGOT:
  418             ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
  419             break;
  420         case DT_REL:
  421             ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
  422             break;
  423         case DT_RELSZ:
  424             ef->relsize = dp->d_un.d_val;
  425             break;
  426         case DT_RELENT:
  427             if (dp->d_un.d_val != sizeof(Elf_Rel))
  428                 return ENOEXEC;
  429             break;
  430         case DT_JMPREL:
  431             ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
  432             break;
  433         case DT_PLTRELSZ:
  434             ef->pltrelsize = dp->d_un.d_val;
  435             break;
  436         case DT_RELA:
  437             ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
  438             break;
  439         case DT_RELASZ:
  440             ef->relasize = dp->d_un.d_val;
  441             break;
  442         case DT_RELAENT:
  443             if (dp->d_un.d_val != sizeof(Elf_Rela))
  444                 return ENOEXEC;
  445             break;
  446         case DT_PLTREL:
  447             plttype = dp->d_un.d_val;
  448             if (plttype != DT_REL && plttype != DT_RELA)
  449                 return ENOEXEC;
  450             break;
  451 #ifdef GDB
  452         case DT_DEBUG:
  453             dp->d_un.d_ptr = (Elf_Addr) &r_debug;
  454             break;
  455 #endif
  456         }
  457     }
  458 
  459     if (plttype == DT_RELA) {
  460         ef->pltrela = (const Elf_Rela *) ef->pltrel;
  461         ef->pltrel = NULL;
  462         ef->pltrelasize = ef->pltrelsize;
  463         ef->pltrelsize = 0;
  464     }
  465 
  466     ef->ddbsymtab = ef->symtab;
  467     ef->ddbsymcnt = ef->nchains;
  468     ef->ddbstrtab = ef->strtab;
  469     ef->ddbstrcnt = ef->strsz;
  470 
  471     return 0;
  472 }
  473 
  474 static int
  475 link_elf_link_preload(linker_class_t cls,
  476                       const char* filename, linker_file_t *result)
  477 {
  478     caddr_t             modptr, baseptr, sizeptr, dynptr;
  479     char                *type;
  480     elf_file_t          ef;
  481     linker_file_t       lf;
  482     int                 error;
  483     vm_offset_t         dp;
  484 
  485     /* Look to see if we have the file preloaded */
  486     modptr = preload_search_by_name(filename);
  487     if (modptr == NULL)
  488         return ENOENT;
  489 
  490     type = (char *)preload_search_info(modptr, MODINFO_TYPE);
  491     baseptr = preload_search_info(modptr, MODINFO_ADDR);
  492     sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  493     dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
  494     if (type == NULL ||
  495         (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
  496          strcmp(type, "elf module") != 0))
  497         return (EFTYPE);
  498     if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
  499         return (EINVAL);
  500 
  501     lf = linker_make_file(filename, &link_elf_class);
  502     if (lf == NULL) {
  503         return ENOMEM;
  504     }
  505 
  506     ef = (elf_file_t) lf;
  507     ef->preloaded = 1;
  508     ef->modptr = modptr;
  509     ef->address = *(caddr_t *)baseptr;
  510 #ifdef SPARSE_MAPPING
  511     ef->object = 0;
  512 #endif
  513     dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
  514     ef->dynamic = (Elf_Dyn *)dp;
  515     lf->address = ef->address;
  516     lf->size = *(size_t *)sizeptr;
  517 
  518     error = parse_dynamic(ef);
  519     if (error) {
  520         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  521         return error;
  522     }
  523     link_elf_reloc_local(lf);
  524     *result = lf;
  525     return (0);
  526 }
  527 
  528 static int
  529 link_elf_link_preload_finish(linker_file_t lf)
  530 {
  531     elf_file_t          ef;
  532     int error;
  533 
  534     ef = (elf_file_t) lf;
  535 #if 0   /* this will be more trouble than it's worth for now */
  536     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  537         if (dp->d_tag != DT_NEEDED)
  538             continue;
  539         modname = ef->strtab + dp->d_un.d_val;
  540         error = linker_load_module(modname, lf);
  541         if (error)
  542             goto out;
  543     }
  544 #endif
  545     error = relocate_file(ef);
  546     if (error)
  547         return error;
  548     (void)link_elf_preload_parse_symbols(ef);
  549 
  550     return (link_elf_link_common_finish(lf));
  551 }
  552 
  553 static int
  554 link_elf_load_file(linker_class_t cls, const char* filename,
  555         linker_file_t* result)
  556 {
  557     struct nameidata nd;
  558     struct thread* td = curthread;      /* XXX */
  559     Elf_Ehdr *hdr;
  560     caddr_t firstpage;
  561     int nbytes, i;
  562     Elf_Phdr *phdr;
  563     Elf_Phdr *phlimit;
  564     Elf_Phdr *segs[MAXSEGS];
  565     int nsegs;
  566     Elf_Phdr *phdyn;
  567     Elf_Phdr *phphdr;
  568     caddr_t mapbase;
  569     size_t mapsize;
  570     Elf_Off base_offset;
  571     Elf_Addr base_vaddr;
  572     Elf_Addr base_vlimit;
  573     int error = 0;
  574     int resid, flags;
  575     elf_file_t ef;
  576     linker_file_t lf;
  577     Elf_Shdr *shdr;
  578     int symtabindex;
  579     int symstrindex;
  580     int symcnt;
  581     int strcnt;
  582     int vfslocked;
  583 
  584     shdr = NULL;
  585     lf = NULL;
  586 
  587     NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
  588     flags = FREAD;
  589     error = vn_open(&nd, &flags, 0, NULL);
  590     if (error)
  591         return error;
  592     vfslocked = NDHASGIANT(&nd);
  593     NDFREE(&nd, NDF_ONLY_PNBUF);
  594     if (nd.ni_vp->v_type != VREG) {
  595         error = ENOEXEC;
  596         firstpage = NULL;
  597         goto out;
  598     }
  599 #ifdef MAC
  600     error = mac_check_kld_load(curthread->td_ucred, nd.ni_vp);
  601     if (error) {
  602         firstpage = NULL;
  603         goto out;
  604     }
  605 #endif
  606 
  607     /*
  608      * Read the elf header from the file.
  609      */
  610     firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
  611     if (firstpage == NULL) {
  612         error = ENOMEM;
  613         goto out;
  614     }
  615     hdr = (Elf_Ehdr *)firstpage;
  616     error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
  617                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  618                     &resid, td);
  619     nbytes = PAGE_SIZE - resid;
  620     if (error)
  621         goto out;
  622 
  623     if (!IS_ELF(*hdr)) {
  624         error = ENOEXEC;
  625         goto out;
  626     }
  627 
  628     if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
  629       || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
  630         link_elf_error(filename, "Unsupported file layout");
  631         error = ENOEXEC;
  632         goto out;
  633     }
  634     if (hdr->e_ident[EI_VERSION] != EV_CURRENT
  635       || hdr->e_version != EV_CURRENT) {
  636         link_elf_error(filename, "Unsupported file version");
  637         error = ENOEXEC;
  638         goto out;
  639     }
  640     if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
  641         link_elf_error(filename, "Unsupported file type");
  642         error = ENOEXEC;
  643         goto out;
  644     }
  645     if (hdr->e_machine != ELF_TARG_MACH) {
  646         link_elf_error(filename, "Unsupported machine");
  647         error = ENOEXEC;
  648         goto out;
  649     }
  650 
  651     /*
  652      * We rely on the program header being in the first page.  This is
  653      * not strictly required by the ABI specification, but it seems to
  654      * always true in practice.  And, it simplifies things considerably.
  655      */
  656     if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
  657           (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
  658           (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
  659         link_elf_error(filename, "Unreadable program headers");
  660 
  661     /*
  662      * Scan the program header entries, and save key information.
  663      *
  664      * We rely on there being exactly two load segments, text and data,
  665      * in that order.
  666      */
  667     phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
  668     phlimit = phdr + hdr->e_phnum;
  669     nsegs = 0;
  670     phdyn = NULL;
  671     phphdr = NULL;
  672     while (phdr < phlimit) {
  673         switch (phdr->p_type) {
  674 
  675         case PT_LOAD:
  676             if (nsegs == MAXSEGS) {
  677                 link_elf_error(filename, "Too many sections");
  678                 error = ENOEXEC;
  679                 goto out;
  680             }
  681             /*
  682              * XXX: We just trust they come in right order ??
  683              */
  684             segs[nsegs] = phdr;
  685             ++nsegs;
  686             break;
  687 
  688         case PT_PHDR:
  689             phphdr = phdr;
  690             break;
  691 
  692         case PT_DYNAMIC:
  693             phdyn = phdr;
  694             break;
  695 
  696         case PT_INTERP:
  697             link_elf_error(filename, "Unsupported file type");
  698             error = ENOEXEC;
  699             goto out;
  700         }
  701 
  702         ++phdr;
  703     }
  704     if (phdyn == NULL) {
  705         link_elf_error(filename, "Object is not dynamically-linked");
  706         error = ENOEXEC;
  707         goto out;
  708     }
  709     if (nsegs == 0) {
  710         link_elf_error(filename, "No sections");
  711         error = ENOEXEC;
  712         goto out;
  713     }
  714 
  715     /*
  716      * Allocate the entire address space of the object, to stake out our
  717      * contiguous region, and to establish the base address for relocation.
  718      */
  719     base_offset = trunc_page(segs[0]->p_offset);
  720     base_vaddr = trunc_page(segs[0]->p_vaddr);
  721     base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 
  722         segs[nsegs - 1]->p_memsz);
  723     mapsize = base_vlimit - base_vaddr;
  724 
  725     lf = linker_make_file(filename, &link_elf_class);
  726     if (!lf) {
  727         error = ENOMEM;
  728         goto out;
  729     }
  730 
  731     ef = (elf_file_t) lf;
  732 #ifdef SPARSE_MAPPING
  733     ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
  734     if (ef->object == NULL) {
  735         error = ENOMEM;
  736         goto out;
  737     }
  738     ef->address = (caddr_t) vm_map_min(kernel_map);
  739     error = vm_map_find(kernel_map, ef->object, 0,
  740                         (vm_offset_t *) &ef->address,
  741                         mapsize, 1,
  742                         VM_PROT_ALL, VM_PROT_ALL, 0);
  743     if (error) {
  744         vm_object_deallocate(ef->object);
  745         ef->object = 0;
  746         goto out;
  747     }
  748 #else
  749     ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
  750     if (!ef->address) {
  751         error = ENOMEM;
  752         goto out;
  753     }
  754 #endif
  755     mapbase = ef->address;
  756 
  757     /*
  758      * Read the text and data sections and zero the bss.
  759      */
  760     for (i = 0; i < nsegs; i++) {
  761         caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
  762         error = vn_rdwr(UIO_READ, nd.ni_vp,
  763                         segbase, segs[i]->p_filesz, segs[i]->p_offset,
  764                         UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  765                         &resid, td);
  766         if (error) {
  767             goto out;
  768         }
  769         bzero(segbase + segs[i]->p_filesz,
  770               segs[i]->p_memsz - segs[i]->p_filesz);
  771 
  772 #ifdef SPARSE_MAPPING
  773         /*
  774          * Wire down the pages
  775          */
  776         error = vm_map_wire(kernel_map,
  777                     (vm_offset_t) segbase,
  778                     (vm_offset_t) segbase + segs[i]->p_memsz,
  779                     VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  780         if (error != KERN_SUCCESS) {
  781             error = ENOMEM;
  782             goto out;
  783         }
  784 #endif
  785     }
  786 
  787 #ifdef GPROF
  788     /* Update profiling information with the new text segment. */
  789     mtx_lock(&Giant);
  790     kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
  791         segs[0]->p_memsz));
  792     mtx_unlock(&Giant);
  793 #endif
  794 
  795     ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
  796 
  797     lf->address = ef->address;
  798     lf->size = mapsize;
  799 
  800     error = parse_dynamic(ef);
  801     if (error)
  802         goto out;
  803     link_elf_reloc_local(lf);
  804 
  805     VOP_UNLOCK(nd.ni_vp, 0, td);
  806     error = linker_load_dependencies(lf);
  807     vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY, td);
  808     if (error)
  809         goto out;
  810 #if 0   /* this will be more trouble than it's worth for now */
  811     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  812         if (dp->d_tag != DT_NEEDED)
  813             continue;
  814         modname = ef->strtab + dp->d_un.d_val;
  815         error = linker_load_module(modname, lf);
  816         if (error)
  817             goto out;
  818     }
  819 #endif
  820     error = relocate_file(ef);
  821     if (error)
  822         goto out;
  823 
  824     /* Try and load the symbol table if it's present.  (you can strip it!) */
  825     nbytes = hdr->e_shnum * hdr->e_shentsize;
  826     if (nbytes == 0 || hdr->e_shoff == 0)
  827         goto nosyms;
  828     shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
  829     if (shdr == NULL) {
  830         error = ENOMEM;
  831         goto out;
  832     }
  833     error = vn_rdwr(UIO_READ, nd.ni_vp,
  834                     (caddr_t)shdr, nbytes, hdr->e_shoff,
  835                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  836                     &resid, td);
  837     if (error)
  838         goto out;
  839     symtabindex = -1;
  840     symstrindex = -1;
  841     for (i = 0; i < hdr->e_shnum; i++) {
  842         if (shdr[i].sh_type == SHT_SYMTAB) {
  843             symtabindex = i;
  844             symstrindex = shdr[i].sh_link;
  845         }
  846     }
  847     if (symtabindex < 0 || symstrindex < 0)
  848         goto nosyms;
  849 
  850     symcnt = shdr[symtabindex].sh_size;
  851     ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
  852     strcnt = shdr[symstrindex].sh_size;
  853     ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
  854 
  855     if (ef->symbase == NULL || ef->strbase == NULL) {
  856         error = ENOMEM;
  857         goto out;
  858     }
  859     error = vn_rdwr(UIO_READ, nd.ni_vp,
  860                     ef->symbase, symcnt, shdr[symtabindex].sh_offset,
  861                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  862                     &resid, td);
  863     if (error)
  864         goto out;
  865     error = vn_rdwr(UIO_READ, nd.ni_vp,
  866                     ef->strbase, strcnt, shdr[symstrindex].sh_offset,
  867                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  868                     &resid, td);
  869     if (error)
  870         goto out;
  871 
  872     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
  873     ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
  874     ef->ddbstrcnt = strcnt;
  875     ef->ddbstrtab = ef->strbase;
  876 
  877     error = link_elf_link_common_finish(lf);
  878     if (error)
  879         goto out;
  880 
  881 nosyms:
  882 
  883     *result = lf;
  884 
  885 out:
  886     if (error && lf)
  887         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  888     if (shdr)
  889         free(shdr, M_LINKER);
  890     if (firstpage)
  891         free(firstpage, M_LINKER);
  892     VOP_UNLOCK(nd.ni_vp, 0, td);
  893     vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  894     VFS_UNLOCK_GIANT(vfslocked);
  895 
  896     return error;
  897 }
  898 
  899 static void
  900 link_elf_unload_file(linker_file_t file)
  901 {
  902     elf_file_t ef = (elf_file_t) file;
  903 
  904 #ifdef GDB
  905     if (ef->gdb.l_ld) {
  906         GDB_STATE(RT_DELETE);
  907         free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
  908         link_elf_delete_gdb(&ef->gdb);
  909         GDB_STATE(RT_CONSISTENT);
  910     }
  911 #endif
  912 
  913     /* Notify MD code that a module is being unloaded. */
  914     elf_cpu_unload_file(file);
  915 
  916     if (ef->preloaded) {
  917         link_elf_unload_preload(file);
  918         return;
  919     }
  920 
  921 #ifdef SPARSE_MAPPING
  922     if (ef->object) {
  923         vm_map_remove(kernel_map, (vm_offset_t) ef->address,
  924                       (vm_offset_t) ef->address
  925                       + (ef->object->size << PAGE_SHIFT));
  926     }
  927 #else
  928     if (ef->address)
  929         free(ef->address, M_LINKER);
  930 #endif
  931     if (ef->symbase)
  932         free(ef->symbase, M_LINKER);
  933     if (ef->strbase)
  934         free(ef->strbase, M_LINKER);
  935     if (ef->ctftab)
  936         free(ef->ctftab, M_LINKER);
  937     if (ef->ctfoff)
  938         free(ef->ctfoff, M_LINKER);
  939     if (ef->typoff)
  940         free(ef->typoff, M_LINKER);
  941 }
  942 
  943 static void
  944 link_elf_unload_preload(linker_file_t file)
  945 {
  946     if (file->filename)
  947         preload_delete_name(file->filename);
  948 }
  949 
  950 static const char *
  951 symbol_name(elf_file_t ef, Elf_Size r_info)
  952 {
  953     const Elf_Sym *ref;
  954 
  955     if (ELF_R_SYM(r_info)) {
  956         ref = ef->symtab + ELF_R_SYM(r_info);
  957         return ef->strtab + ref->st_name;
  958     } else
  959         return NULL;
  960 }
  961 
  962 static int
  963 relocate_file(elf_file_t ef)
  964 {
  965     const Elf_Rel *rellim;
  966     const Elf_Rel *rel;
  967     const Elf_Rela *relalim;
  968     const Elf_Rela *rela;
  969     const char *symname;
  970 
  971     /* Perform relocations without addend if there are any: */
  972     rel = ef->rel;
  973     if (rel) {
  974         rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
  975         while (rel < rellim) {
  976             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
  977                           elf_lookup)) {
  978                 symname = symbol_name(ef, rel->r_info);
  979                 printf("link_elf: symbol %s undefined\n", symname);
  980                 return ENOENT;
  981             }
  982             rel++;
  983         }
  984     }
  985 
  986     /* Perform relocations with addend if there are any: */
  987     rela = ef->rela;
  988     if (rela) {
  989         relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
  990         while (rela < relalim) {
  991             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
  992                           elf_lookup)) {
  993                 symname = symbol_name(ef, rela->r_info);
  994                 printf("link_elf: symbol %s undefined\n", symname);
  995                 return ENOENT;
  996             }
  997             rela++;
  998         }
  999     }
 1000 
 1001     /* Perform PLT relocations without addend if there are any: */
 1002     rel = ef->pltrel;
 1003     if (rel) {
 1004         rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
 1005         while (rel < rellim) {
 1006             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
 1007                           elf_lookup)) {
 1008                 symname = symbol_name(ef, rel->r_info);
 1009                 printf("link_elf: symbol %s undefined\n", symname);
 1010                 return ENOENT;
 1011             }
 1012             rel++;
 1013         }
 1014     }
 1015 
 1016     /* Perform relocations with addend if there are any: */
 1017     rela = ef->pltrela;
 1018     if (rela) {
 1019         relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
 1020         while (rela < relalim) {
 1021             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
 1022                           elf_lookup)) {
 1023                 symname = symbol_name(ef, rela->r_info);
 1024                 printf("link_elf: symbol %s undefined\n", symname);
 1025                 return ENOENT;
 1026             }
 1027             rela++;
 1028         }
 1029     }
 1030 
 1031     return 0;
 1032 }
 1033 
 1034 /*
 1035  * Hash function for symbol table lookup.  Don't even think about changing
 1036  * this.  It is specified by the System V ABI.
 1037  */
 1038 static unsigned long
 1039 elf_hash(const char *name)
 1040 {
 1041     const unsigned char *p = (const unsigned char *) name;
 1042     unsigned long h = 0;
 1043     unsigned long g;
 1044 
 1045     while (*p != '\0') {
 1046         h = (h << 4) + *p++;
 1047         if ((g = h & 0xf0000000) != 0)
 1048             h ^= g >> 24;
 1049         h &= ~g;
 1050     }
 1051     return h;
 1052 }
 1053 
 1054 static int
 1055 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
 1056 {
 1057     elf_file_t ef = (elf_file_t) lf;
 1058     unsigned long symnum;
 1059     const Elf_Sym* symp;
 1060     const char *strp;
 1061     unsigned long hash;
 1062     int i;
 1063 
 1064     /* If we don't have a hash, bail. */
 1065     if (ef->buckets == NULL || ef->nbuckets == 0) {
 1066         printf("link_elf_lookup_symbol: missing symbol hash table\n");
 1067         return ENOENT;
 1068     }
 1069 
 1070     /* First, search hashed global symbols */
 1071     hash = elf_hash(name);
 1072     symnum = ef->buckets[hash % ef->nbuckets];
 1073 
 1074     while (symnum != STN_UNDEF) {
 1075         if (symnum >= ef->nchains) {
 1076             printf("link_elf_lookup_symbol: corrupt symbol table\n");
 1077             return ENOENT;
 1078         }
 1079 
 1080         symp = ef->symtab + symnum;
 1081         if (symp->st_name == 0) {
 1082             printf("link_elf_lookup_symbol: corrupt symbol table\n");
 1083             return ENOENT;
 1084         }
 1085 
 1086         strp = ef->strtab + symp->st_name;
 1087 
 1088         if (strcmp(name, strp) == 0) {
 1089             if (symp->st_shndx != SHN_UNDEF ||
 1090                 (symp->st_value != 0 &&
 1091                  ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
 1092                 *sym = (c_linker_sym_t) symp;
 1093                 return 0;
 1094             } else
 1095                 return ENOENT;
 1096         }
 1097 
 1098         symnum = ef->chains[symnum];
 1099     }
 1100 
 1101     /* If we have not found it, look at the full table (if loaded) */
 1102     if (ef->symtab == ef->ddbsymtab)
 1103         return ENOENT;
 1104 
 1105     /* Exhaustive search */
 1106     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1107         strp = ef->ddbstrtab + symp->st_name;
 1108         if (strcmp(name, strp) == 0) {
 1109             if (symp->st_shndx != SHN_UNDEF ||
 1110                 (symp->st_value != 0 &&
 1111                  ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
 1112                 *sym = (c_linker_sym_t) symp;
 1113                 return 0;
 1114             } else
 1115                 return ENOENT;
 1116         }
 1117     }
 1118 
 1119     return ENOENT;
 1120 }
 1121 
 1122 static int
 1123 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
 1124 {
 1125         elf_file_t ef = (elf_file_t) lf;
 1126         const Elf_Sym* es = (const Elf_Sym*) sym;
 1127 
 1128         if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
 1129             symval->name = ef->strtab + es->st_name;
 1130             symval->value = (caddr_t) ef->address + es->st_value;
 1131             symval->size = es->st_size;
 1132             return 0;
 1133         }
 1134         if (ef->symtab == ef->ddbsymtab)
 1135             return ENOENT;
 1136         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 1137             symval->name = ef->ddbstrtab + es->st_name;
 1138             symval->value = (caddr_t) ef->address + es->st_value;
 1139             symval->size = es->st_size;
 1140             return 0;
 1141         }
 1142         return ENOENT;
 1143 }
 1144 
 1145 static int
 1146 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 1147                        c_linker_sym_t* sym, long* diffp)
 1148 {
 1149         elf_file_t ef = (elf_file_t) lf;
 1150         u_long off = (uintptr_t) (void *) value;
 1151         u_long diff = off;
 1152         u_long st_value;
 1153         const Elf_Sym* es;
 1154         const Elf_Sym* best = 0;
 1155         int i;
 1156 
 1157         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 1158                 if (es->st_name == 0)
 1159                         continue;
 1160                 st_value = es->st_value + (uintptr_t) (void *) ef->address;
 1161                 if (off >= st_value) {
 1162                         if (off - st_value < diff) {
 1163                                 diff = off - st_value;
 1164                                 best = es;
 1165                                 if (diff == 0)
 1166                                         break;
 1167                         } else if (off - st_value == diff) {
 1168                                 best = es;
 1169                         }
 1170                 }
 1171         }
 1172         if (best == 0)
 1173                 *diffp = off;
 1174         else
 1175                 *diffp = diff;
 1176         *sym = (c_linker_sym_t) best;
 1177 
 1178         return 0;
 1179 }
 1180 
 1181 /*
 1182  * Look up a linker set on an ELF system.
 1183  */
 1184 static int
 1185 link_elf_lookup_set(linker_file_t lf, const char *name,
 1186                     void ***startp, void ***stopp, int *countp)
 1187 {
 1188         c_linker_sym_t sym;
 1189         linker_symval_t symval;
 1190         char *setsym;
 1191         void **start, **stop;
 1192         int len, error = 0, count;
 1193 
 1194         len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
 1195         setsym = malloc(len, M_LINKER, M_WAITOK);
 1196         if (setsym == NULL)
 1197                 return ENOMEM;
 1198 
 1199         /* get address of first entry */
 1200         snprintf(setsym, len, "%s%s", "__start_set_", name);
 1201         error = link_elf_lookup_symbol(lf, setsym, &sym);
 1202         if (error)
 1203                 goto out;
 1204         link_elf_symbol_values(lf, sym, &symval);
 1205         if (symval.value == 0) {
 1206                 error = ESRCH;
 1207                 goto out;
 1208         }
 1209         start = (void **)symval.value;
 1210 
 1211         /* get address of last entry */
 1212         snprintf(setsym, len, "%s%s", "__stop_set_", name);
 1213         error = link_elf_lookup_symbol(lf, setsym, &sym);
 1214         if (error)
 1215                 goto out;
 1216         link_elf_symbol_values(lf, sym, &symval);
 1217         if (symval.value == 0) {
 1218                 error = ESRCH;
 1219                 goto out;
 1220         }
 1221         stop = (void **)symval.value;
 1222 
 1223         /* and the number of entries */
 1224         count = stop - start;
 1225 
 1226         /* and copy out */
 1227         if (startp)
 1228                 *startp = start;
 1229         if (stopp)
 1230                 *stopp = stop;
 1231         if (countp)
 1232                 *countp = count;
 1233 
 1234 out:
 1235         free(setsym, M_LINKER);
 1236         return error;
 1237 }
 1238 
 1239 static int
 1240 link_elf_each_function_name(linker_file_t file,
 1241   int (*callback)(const char *, void *), void *opaque) {
 1242     elf_file_t ef = (elf_file_t)file;
 1243     const Elf_Sym* symp;
 1244     int i, error;
 1245         
 1246     /* Exhaustive search */
 1247     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1248         if (symp->st_value != 0 &&
 1249             ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1250                 error = callback(ef->ddbstrtab + symp->st_name, opaque);
 1251                 if (error)
 1252                     return (error);
 1253         }
 1254     }
 1255     return (0);
 1256 }
 1257 
 1258 static int
 1259 link_elf_each_function_nameval(linker_file_t file,
 1260     linker_function_nameval_callback_t callback, void *opaque)
 1261 {
 1262         linker_symval_t symval;
 1263         elf_file_t ef = (elf_file_t)file;
 1264         const Elf_Sym* symp;
 1265         int i, error;
 1266 
 1267         /* Exhaustive search */
 1268         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1269                 if (symp->st_value != 0 &&
 1270                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1271                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
 1272                         if (error)
 1273                                 return (error);
 1274                         error = callback(file, i, &symval, opaque);
 1275                         if (error)
 1276                                 return (error);
 1277                 }
 1278         }
 1279         return (0);
 1280 }
 1281 
 1282 #ifdef __ia64__
 1283 /*
 1284  * Each KLD has its own GP. The GP value for each load module is given by
 1285  * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
 1286  * don't have direct access to the ELF file structure. The link_elf_get_gp()
 1287  * function returns the GP given a pointer to a generic linker file struct.
 1288  */
 1289 Elf_Addr
 1290 link_elf_get_gp(linker_file_t lf)
 1291 {
 1292         elf_file_t ef = (elf_file_t)lf;
 1293         return (Elf_Addr)ef->got;
 1294 }
 1295 #endif
 1296 
 1297 const Elf_Sym *
 1298 elf_get_sym(linker_file_t lf, Elf_Size symidx)
 1299 {
 1300         elf_file_t ef = (elf_file_t)lf;
 1301 
 1302         if (symidx >= ef->nchains)
 1303                 return (NULL);
 1304         return (ef->symtab + symidx);
 1305 }
 1306 
 1307 const char *
 1308 elf_get_symname(linker_file_t lf, Elf_Size symidx)
 1309 {
 1310         elf_file_t ef = (elf_file_t)lf;
 1311         const Elf_Sym *sym;
 1312 
 1313         if (symidx >= ef->nchains)
 1314                 return (NULL);
 1315         sym = ef->symtab + symidx;
 1316         return (ef->strtab + sym->st_name);
 1317 }
 1318 
 1319 /*
 1320  * Symbol lookup function that can be used when the symbol index is known (ie
 1321  * in relocations). It uses the symbol index instead of doing a fully fledged
 1322  * hash table based lookup when such is valid. For example for local symbols.
 1323  * This is not only more efficient, it's also more correct. It's not always
 1324  * the case that the symbol can be found through the hash table.
 1325  */
 1326 static Elf_Addr
 1327 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
 1328 {
 1329         elf_file_t ef = (elf_file_t)lf;
 1330         const Elf_Sym *sym;
 1331         const char *symbol;
 1332 
 1333         /* Don't even try to lookup the symbol if the index is bogus. */
 1334         if (symidx >= ef->nchains)
 1335                 return (0);
 1336 
 1337         sym = ef->symtab + symidx;
 1338 
 1339         /*
 1340          * Don't do a full lookup when the symbol is local. It may even
 1341          * fail because it may not be found through the hash table.
 1342          */
 1343         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
 1344                 /* Force lookup failure when we have an insanity. */
 1345                 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
 1346                         return (0);
 1347                 return ((Elf_Addr)ef->address + sym->st_value);
 1348         }
 1349 
 1350         /*
 1351          * XXX we can avoid doing a hash table based lookup for global
 1352          * symbols as well. This however is not always valid, so we'll
 1353          * just do it the hard way for now. Performance tweaks can
 1354          * always be added.
 1355          */
 1356 
 1357         symbol = ef->strtab + sym->st_name;
 1358 
 1359         /* Force a lookup failure if the symbol name is bogus. */
 1360         if (*symbol == 0)
 1361                 return (0);
 1362 
 1363         return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
 1364 }
 1365 
 1366 static void
 1367 link_elf_reloc_local(linker_file_t lf)
 1368 {
 1369     const Elf_Rel *rellim;
 1370     const Elf_Rel *rel;
 1371     const Elf_Rela *relalim;
 1372     const Elf_Rela *rela;
 1373     elf_file_t ef = (elf_file_t)lf;
 1374 
 1375     /* Perform relocations without addend if there are any: */
 1376     if ((rel = ef->rel) != NULL) {
 1377         rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
 1378         while (rel < rellim) {
 1379             elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
 1380                             elf_lookup);
 1381             rel++;
 1382         }
 1383     }
 1384 
 1385     /* Perform relocations with addend if there are any: */
 1386     if ((rela = ef->rela) != NULL) {
 1387         relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
 1388         while (rela < relalim) {
 1389             elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
 1390                             elf_lookup);
 1391             rela++;
 1392         }
 1393     }
 1394 }

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