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


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

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

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

    1 /*-
    2  * Copyright (c) 1998-2000 Doug Rabson
    3  * 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: releng/8.1/sys/kern/link_elf.c 199583 2009-11-20 15:27:52Z jhb $");
   29 
   30 #include "opt_ddb.h"
   31 #include "opt_gdb.h"
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #ifdef GPROF
   36 #include <sys/gmon.h>
   37 #endif
   38 #include <sys/kernel.h>
   39 #include <sys/lock.h>
   40 #include <sys/malloc.h>
   41 #include <sys/mutex.h>
   42 #include <sys/mount.h>
   43 #include <sys/pcpu.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 <net/vnet.h>
   53 
   54 #include <security/mac/mac_framework.h>
   55 
   56 #include <vm/vm.h>
   57 #include <vm/vm_param.h>
   58 #ifdef SPARSE_MAPPING
   59 #include <vm/vm_object.h>
   60 #include <vm/vm_kern.h>
   61 #include <vm/vm_extern.h>
   62 #endif
   63 #include <vm/pmap.h>
   64 #include <vm/vm_map.h>
   65 
   66 #include <sys/link_elf.h>
   67 
   68 #ifdef DDB_CTF
   69 #include <net/zlib.h>
   70 #endif
   71 
   72 #include "linker_if.h"
   73 
   74 #define MAXSEGS 4
   75 
   76 typedef struct elf_file {
   77     struct linker_file  lf;             /* Common fields */
   78     int                 preloaded;      /* Was file pre-loaded */
   79     caddr_t             address;        /* Relocation address */
   80 #ifdef SPARSE_MAPPING
   81     vm_object_t         object;         /* VM object to hold file pages */
   82 #endif
   83     Elf_Dyn*            dynamic;        /* Symbol table etc. */
   84     Elf_Hashelt         nbuckets;       /* DT_HASH info */
   85     Elf_Hashelt         nchains;
   86     const Elf_Hashelt*  buckets;
   87     const Elf_Hashelt*  chains;
   88     caddr_t             hash;
   89     caddr_t             strtab;         /* DT_STRTAB */
   90     int                 strsz;          /* DT_STRSZ */
   91     const Elf_Sym*      symtab;         /* DT_SYMTAB */
   92     Elf_Addr*           got;            /* DT_PLTGOT */
   93     const Elf_Rel*      pltrel;         /* DT_JMPREL */
   94     int                 pltrelsize;     /* DT_PLTRELSZ */
   95     const Elf_Rela*     pltrela;        /* DT_JMPREL */
   96     int                 pltrelasize;    /* DT_PLTRELSZ */
   97     const Elf_Rel*      rel;            /* DT_REL */
   98     int                 relsize;        /* DT_RELSZ */
   99     const Elf_Rela*     rela;           /* DT_RELA */
  100     int                 relasize;       /* DT_RELASZ */
  101     caddr_t             modptr;
  102     const Elf_Sym*      ddbsymtab;      /* The symbol table we are using */
  103     long                ddbsymcnt;      /* Number of symbols */
  104     caddr_t             ddbstrtab;      /* String table */
  105     long                ddbstrcnt;      /* number of bytes in string table */
  106     caddr_t             symbase;        /* malloc'ed symbold base */
  107     caddr_t             strbase;        /* malloc'ed string base */
  108     caddr_t             ctftab;         /* CTF table */
  109     long                ctfcnt;         /* number of bytes in CTF table */
  110     caddr_t             ctfoff;         /* CTF offset table */
  111     caddr_t             typoff;         /* Type offset table */
  112     long                typlen;         /* Number of type entries. */
  113     Elf_Addr            pcpu_start;     /* Pre-relocation pcpu set start. */
  114     Elf_Addr            pcpu_stop;      /* Pre-relocation pcpu set stop. */
  115     Elf_Addr            pcpu_base;      /* Relocated pcpu set address. */
  116 #ifdef VIMAGE
  117     Elf_Addr            vnet_start;     /* Pre-relocation vnet set start. */
  118     Elf_Addr            vnet_stop;      /* Pre-relocation vnet set stop. */
  119     Elf_Addr            vnet_base;      /* Relocated vnet set address. */
  120 #endif
  121 #ifdef GDB
  122     struct link_map     gdb;            /* hooks for gdb */
  123 #endif
  124 } *elf_file_t;
  125 
  126 #include <kern/kern_ctf.c>
  127 
  128 static int      link_elf_link_common_finish(linker_file_t);
  129 static int      link_elf_link_preload(linker_class_t cls,
  130                                       const char*, linker_file_t*);
  131 static int      link_elf_link_preload_finish(linker_file_t);
  132 static int      link_elf_load_file(linker_class_t, const char*, linker_file_t*);
  133 static int      link_elf_lookup_symbol(linker_file_t, const char*,
  134                                        c_linker_sym_t*);
  135 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*);
  136 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
  137                                        c_linker_sym_t* sym, long* diffp);
  138 
  139 static void     link_elf_unload_file(linker_file_t);
  140 static void     link_elf_unload_preload(linker_file_t);
  141 static int      link_elf_lookup_set(linker_file_t, const char *,
  142                                     void ***, void ***, int *);
  143 static int      link_elf_each_function_name(linker_file_t,
  144                                 int (*)(const char *, void *),
  145                                 void *);
  146 static int      link_elf_each_function_nameval(linker_file_t,
  147                                 linker_function_nameval_callback_t,
  148                                 void *);
  149 static void     link_elf_reloc_local(linker_file_t);
  150 static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
  151 static long     link_elf_strtab_get(linker_file_t, caddr_t *);
  152 static Elf_Addr elf_lookup(linker_file_t lf, Elf_Size symidx, int deps);
  153 
  154 static kobj_method_t link_elf_methods[] = {
  155     KOBJMETHOD(linker_lookup_symbol,    link_elf_lookup_symbol),
  156     KOBJMETHOD(linker_symbol_values,    link_elf_symbol_values),
  157     KOBJMETHOD(linker_search_symbol,    link_elf_search_symbol),
  158     KOBJMETHOD(linker_unload,           link_elf_unload_file),
  159     KOBJMETHOD(linker_load_file,        link_elf_load_file),
  160     KOBJMETHOD(linker_link_preload,     link_elf_link_preload),
  161     KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
  162     KOBJMETHOD(linker_lookup_set,       link_elf_lookup_set),
  163     KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
  164     KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
  165     KOBJMETHOD(linker_ctf_get,          link_elf_ctf_get),
  166     KOBJMETHOD(linker_symtab_get,       link_elf_symtab_get),
  167     KOBJMETHOD(linker_strtab_get,       link_elf_strtab_get),
  168     { 0, 0 }
  169 };
  170 
  171 static struct linker_class link_elf_class = {
  172 #if ELF_TARG_CLASS == ELFCLASS32
  173     "elf32",
  174 #else
  175     "elf64",
  176 #endif
  177     link_elf_methods, sizeof(struct elf_file)
  178 };
  179 
  180 static int              parse_dynamic(elf_file_t ef);
  181 static int              relocate_file(elf_file_t ef);
  182 static int              link_elf_preload_parse_symbols(elf_file_t ef);
  183 
  184 #ifdef GDB
  185 static void             r_debug_state(struct r_debug *dummy_one,
  186                                       struct link_map *dummy_two);
  187 
  188 /*
  189  * A list of loaded modules for GDB to use for loading symbols.
  190  */
  191 struct r_debug r_debug;
  192 
  193 #define GDB_STATE(s)    r_debug.r_state = s; r_debug_state(NULL, NULL);
  194 
  195 /*
  196  * Function for the debugger to set a breakpoint on to gain control.
  197  */
  198 static void
  199 r_debug_state(struct r_debug *dummy_one __unused,
  200               struct link_map *dummy_two __unused)
  201 {
  202 }
  203 
  204 static void
  205 link_elf_add_gdb(struct link_map *l)
  206 {
  207     struct link_map *prev;
  208 
  209     l->l_next = NULL;
  210 
  211     if (r_debug.r_map == NULL) {
  212         /* Add first. */
  213         l->l_prev = NULL;
  214         r_debug.r_map = l;
  215     } else {
  216         /* Append to list. */
  217         for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next)
  218             ;
  219         l->l_prev = prev;
  220         prev->l_next = l;
  221     }
  222 }
  223 
  224 static void
  225 link_elf_delete_gdb(struct link_map *l)
  226 {
  227     if (l->l_prev == NULL) {
  228         /* Remove first. */
  229         if ((r_debug.r_map = l->l_next) != NULL)
  230             l->l_next->l_prev = NULL;
  231     } else {
  232         /* Remove any but first. */
  233         if ((l->l_prev->l_next = l->l_next) != NULL)
  234             l->l_next->l_prev = l->l_prev;
  235     }
  236 }
  237 #endif /* GDB */
  238 
  239 #ifdef __ia64__
  240 Elf_Addr link_elf_get_gp(linker_file_t);
  241 #endif
  242 
  243 /*
  244  * The kernel symbol table starts here.
  245  */
  246 extern struct _dynamic _DYNAMIC;
  247 
  248 static void
  249 link_elf_error(const char *filename, const char *s)
  250 {
  251         if (filename == NULL)
  252                 printf("kldload: %s\n", s);
  253         else
  254                 printf("kldload: %s: %s\n", filename, s);
  255 }
  256 
  257 /*
  258  * Actions performed after linking/loading both the preloaded kernel and any
  259  * modules; whether preloaded or dynamicly loaded.
  260  */
  261 static int
  262 link_elf_link_common_finish(linker_file_t lf)
  263 {
  264 #ifdef GDB
  265     elf_file_t ef = (elf_file_t)lf;
  266     char *newfilename;
  267 #endif
  268     int error;
  269 
  270     /* Notify MD code that a module is being loaded. */
  271     error = elf_cpu_load_file(lf);
  272     if (error)
  273         return (error);
  274 
  275 #ifdef GDB
  276     GDB_STATE(RT_ADD);
  277     ef->gdb.l_addr = lf->address;
  278     newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK);
  279     strcpy(newfilename, lf->filename);
  280     ef->gdb.l_name = newfilename;
  281     ef->gdb.l_ld = ef->dynamic;
  282     link_elf_add_gdb(&ef->gdb);
  283     GDB_STATE(RT_CONSISTENT);
  284 #endif
  285 
  286     return (0);
  287 }
  288 
  289 static void
  290 link_elf_init(void* arg)
  291 {
  292     Elf_Dyn     *dp;
  293     caddr_t     modptr, baseptr, sizeptr;
  294     elf_file_t  ef;
  295     char        *modname;
  296 
  297     linker_add_class(&link_elf_class);
  298 
  299     dp = (Elf_Dyn*) &_DYNAMIC;
  300     modname = NULL;
  301     modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel");
  302     if (modptr == NULL)
  303         modptr = preload_search_by_type("elf kernel");
  304     if (modptr)
  305         modname = (char *)preload_search_info(modptr, MODINFO_NAME);
  306     if (modname == NULL)
  307         modname = "kernel";
  308     linker_kernel_file = linker_make_file(modname, &link_elf_class);
  309     if (linker_kernel_file == NULL)
  310         panic("link_elf_init: Can't create linker structures for kernel");
  311 
  312     ef = (elf_file_t) linker_kernel_file;
  313     ef->preloaded = 1;
  314     ef->address = 0;
  315 #ifdef SPARSE_MAPPING
  316     ef->object = 0;
  317 #endif
  318     ef->dynamic = dp;
  319 
  320     if (dp)
  321         parse_dynamic(ef);
  322     linker_kernel_file->address = (caddr_t) KERNBASE;
  323     linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
  324 
  325     if (modptr) {
  326         ef->modptr = modptr;
  327         baseptr = preload_search_info(modptr, MODINFO_ADDR);
  328         if (baseptr)
  329             linker_kernel_file->address = *(caddr_t *)baseptr;
  330         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  331         if (sizeptr)
  332             linker_kernel_file->size = *(size_t *)sizeptr;
  333     }
  334     (void)link_elf_preload_parse_symbols(ef);
  335 
  336 #ifdef GDB
  337     r_debug.r_map = NULL;
  338     r_debug.r_brk = r_debug_state;
  339     r_debug.r_state = RT_CONSISTENT;
  340 #endif
  341 
  342     (void)link_elf_link_common_finish(linker_kernel_file);
  343     linker_kernel_file->flags |= LINKER_FILE_LINKED;
  344 }
  345 
  346 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0);
  347 
  348 static int
  349 link_elf_preload_parse_symbols(elf_file_t ef)
  350 {
  351     caddr_t     pointer;
  352     caddr_t     ssym, esym, base;
  353     caddr_t     strtab;
  354     int         strcnt;
  355     Elf_Sym*    symtab;
  356     int         symcnt;
  357 
  358     if (ef->modptr == NULL)
  359         return 0;
  360     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM);
  361     if (pointer == NULL)
  362         return 0;
  363     ssym = *(caddr_t *)pointer;
  364     pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM);
  365     if (pointer == NULL)
  366         return 0;
  367     esym = *(caddr_t *)pointer;
  368 
  369     base = ssym;
  370 
  371     symcnt = *(long *)base;
  372     base += sizeof(long);
  373     symtab = (Elf_Sym *)base;
  374     base += roundup(symcnt, sizeof(long));
  375 
  376     if (base > esym || base < ssym) {
  377         printf("Symbols are corrupt!\n");
  378         return EINVAL;
  379     }
  380 
  381     strcnt = *(long *)base;
  382     base += sizeof(long);
  383     strtab = base;
  384     base += roundup(strcnt, sizeof(long));
  385 
  386     if (base > esym || base < ssym) {
  387         printf("Symbols are corrupt!\n");
  388         return EINVAL;
  389     }
  390 
  391     ef->ddbsymtab = symtab;
  392     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
  393     ef->ddbstrtab = strtab;
  394     ef->ddbstrcnt = strcnt;
  395 
  396     return 0;
  397 }
  398 
  399 static int
  400 parse_dynamic(elf_file_t ef)
  401 {
  402     Elf_Dyn *dp;
  403     int plttype = DT_REL;
  404 
  405     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  406         switch (dp->d_tag) {
  407         case DT_HASH:
  408         {
  409             /* From src/libexec/rtld-elf/rtld.c */
  410             const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
  411                 (ef->address + dp->d_un.d_ptr);
  412             ef->nbuckets = hashtab[0];
  413             ef->nchains = hashtab[1];
  414             ef->buckets = hashtab + 2;
  415             ef->chains = ef->buckets + ef->nbuckets;
  416             break;
  417         }
  418         case DT_STRTAB:
  419             ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr);
  420             break;
  421         case DT_STRSZ:
  422             ef->strsz = dp->d_un.d_val;
  423             break;
  424         case DT_SYMTAB:
  425             ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr);
  426             break;
  427         case DT_SYMENT:
  428             if (dp->d_un.d_val != sizeof(Elf_Sym))
  429                 return ENOEXEC;
  430             break;
  431         case DT_PLTGOT:
  432             ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr);
  433             break;
  434         case DT_REL:
  435             ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
  436             break;
  437         case DT_RELSZ:
  438             ef->relsize = dp->d_un.d_val;
  439             break;
  440         case DT_RELENT:
  441             if (dp->d_un.d_val != sizeof(Elf_Rel))
  442                 return ENOEXEC;
  443             break;
  444         case DT_JMPREL:
  445             ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr);
  446             break;
  447         case DT_PLTRELSZ:
  448             ef->pltrelsize = dp->d_un.d_val;
  449             break;
  450         case DT_RELA:
  451             ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr);
  452             break;
  453         case DT_RELASZ:
  454             ef->relasize = dp->d_un.d_val;
  455             break;
  456         case DT_RELAENT:
  457             if (dp->d_un.d_val != sizeof(Elf_Rela))
  458                 return ENOEXEC;
  459             break;
  460         case DT_PLTREL:
  461             plttype = dp->d_un.d_val;
  462             if (plttype != DT_REL && plttype != DT_RELA)
  463                 return ENOEXEC;
  464             break;
  465 #ifdef GDB
  466         case DT_DEBUG:
  467             dp->d_un.d_ptr = (Elf_Addr) &r_debug;
  468             break;
  469 #endif
  470         }
  471     }
  472 
  473     if (plttype == DT_RELA) {
  474         ef->pltrela = (const Elf_Rela *) ef->pltrel;
  475         ef->pltrel = NULL;
  476         ef->pltrelasize = ef->pltrelsize;
  477         ef->pltrelsize = 0;
  478     }
  479 
  480     ef->ddbsymtab = ef->symtab;
  481     ef->ddbsymcnt = ef->nchains;
  482     ef->ddbstrtab = ef->strtab;
  483     ef->ddbstrcnt = ef->strsz;
  484 
  485     return 0;
  486 }
  487 
  488 static int
  489 parse_dpcpu(elf_file_t ef)
  490 { 
  491     int count;
  492     int error;
  493 
  494     ef->pcpu_start = 0;
  495     ef->pcpu_stop = 0;
  496     error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start,
  497                                (void ***)&ef->pcpu_stop, &count);
  498     /* Error just means there is no pcpu set to relocate. */
  499     if (error)
  500         return (0);
  501     count *= sizeof(void *);
  502     /*
  503      * Allocate space in the primary pcpu area.  Copy in our initialization
  504      * from the data section and then initialize all per-cpu storage from
  505      * that.
  506      */
  507     ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count);
  508     if (ef->pcpu_base == (Elf_Addr)NULL)
  509         return (ENOSPC);
  510     memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count);
  511     dpcpu_copy((void *)ef->pcpu_base, count);
  512 
  513     return (0);
  514 }
  515 
  516 #ifdef VIMAGE
  517 static int
  518 parse_vnet(elf_file_t ef)
  519 { 
  520     int count;
  521     int error;
  522 
  523     ef->vnet_start = 0;
  524     ef->vnet_stop = 0;
  525     error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start,
  526                                (void ***)&ef->vnet_stop, &count);
  527     /* Error just means there is no vnet data set to relocate. */
  528     if (error)
  529         return (0);
  530     count *= sizeof(void *);
  531     /*
  532      * Allocate space in the primary vnet area.  Copy in our initialization
  533      * from the data section and then initialize all per-vnet storage from
  534      * that.
  535      */
  536     ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count);
  537     if (ef->vnet_base == (Elf_Addr)NULL)
  538         return (ENOSPC);
  539     memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count);
  540     vnet_data_copy((void *)ef->vnet_base, count);
  541 
  542     return (0);
  543 }
  544 #endif
  545 
  546 static int
  547 link_elf_link_preload(linker_class_t cls,
  548                       const char* filename, linker_file_t *result)
  549 {
  550     caddr_t             modptr, baseptr, sizeptr, dynptr;
  551     char                *type;
  552     elf_file_t          ef;
  553     linker_file_t       lf;
  554     int                 error;
  555     vm_offset_t         dp;
  556 
  557     /* Look to see if we have the file preloaded */
  558     modptr = preload_search_by_name(filename);
  559     if (modptr == NULL)
  560         return ENOENT;
  561 
  562     type = (char *)preload_search_info(modptr, MODINFO_TYPE);
  563     baseptr = preload_search_info(modptr, MODINFO_ADDR);
  564     sizeptr = preload_search_info(modptr, MODINFO_SIZE);
  565     dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC);
  566     if (type == NULL ||
  567         (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 &&
  568          strcmp(type, "elf module") != 0))
  569         return (EFTYPE);
  570     if (baseptr == NULL || sizeptr == NULL || dynptr == NULL)
  571         return (EINVAL);
  572 
  573     lf = linker_make_file(filename, &link_elf_class);
  574     if (lf == NULL) {
  575         return ENOMEM;
  576     }
  577 
  578     ef = (elf_file_t) lf;
  579     ef->preloaded = 1;
  580     ef->modptr = modptr;
  581     ef->address = *(caddr_t *)baseptr;
  582 #ifdef SPARSE_MAPPING
  583     ef->object = 0;
  584 #endif
  585     dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr;
  586     ef->dynamic = (Elf_Dyn *)dp;
  587     lf->address = ef->address;
  588     lf->size = *(size_t *)sizeptr;
  589 
  590     error = parse_dynamic(ef);
  591     if (error == 0)
  592         error = parse_dpcpu(ef);
  593 #ifdef VIMAGE
  594     if (error == 0)
  595         error = parse_vnet(ef);
  596 #endif
  597     if (error) {
  598         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  599         return error;
  600     }
  601     link_elf_reloc_local(lf);
  602     *result = lf;
  603     return (0);
  604 }
  605 
  606 static int
  607 link_elf_link_preload_finish(linker_file_t lf)
  608 {
  609     elf_file_t          ef;
  610     int error;
  611 
  612     ef = (elf_file_t) lf;
  613 #if 0   /* this will be more trouble than it's worth for now */
  614     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  615         if (dp->d_tag != DT_NEEDED)
  616             continue;
  617         modname = ef->strtab + dp->d_un.d_val;
  618         error = linker_load_module(modname, lf);
  619         if (error)
  620             goto out;
  621     }
  622 #endif
  623     error = relocate_file(ef);
  624     if (error)
  625         return error;
  626     (void)link_elf_preload_parse_symbols(ef);
  627 
  628     return (link_elf_link_common_finish(lf));
  629 }
  630 
  631 static int
  632 link_elf_load_file(linker_class_t cls, const char* filename,
  633         linker_file_t* result)
  634 {
  635     struct nameidata nd;
  636     struct thread* td = curthread;      /* XXX */
  637     Elf_Ehdr *hdr;
  638     caddr_t firstpage;
  639     int nbytes, i;
  640     Elf_Phdr *phdr;
  641     Elf_Phdr *phlimit;
  642     Elf_Phdr *segs[MAXSEGS];
  643     int nsegs;
  644     Elf_Phdr *phdyn;
  645     Elf_Phdr *phphdr;
  646     caddr_t mapbase;
  647     size_t mapsize;
  648     Elf_Off base_offset;
  649     Elf_Addr base_vaddr;
  650     Elf_Addr base_vlimit;
  651     int error = 0;
  652     int resid, flags;
  653     elf_file_t ef;
  654     linker_file_t lf;
  655     Elf_Shdr *shdr;
  656     int symtabindex;
  657     int symstrindex;
  658     int symcnt;
  659     int strcnt;
  660     int vfslocked;
  661 
  662     shdr = NULL;
  663     lf = NULL;
  664 
  665     NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
  666     flags = FREAD;
  667     error = vn_open(&nd, &flags, 0, NULL);
  668     if (error)
  669         return error;
  670     vfslocked = NDHASGIANT(&nd);
  671     NDFREE(&nd, NDF_ONLY_PNBUF);
  672     if (nd.ni_vp->v_type != VREG) {
  673         error = ENOEXEC;
  674         firstpage = NULL;
  675         goto out;
  676     }
  677 #ifdef MAC
  678     error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp);
  679     if (error) {
  680         firstpage = NULL;
  681         goto out;
  682     }
  683 #endif
  684 
  685     /*
  686      * Read the elf header from the file.
  687      */
  688     firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK);
  689     if (firstpage == NULL) {
  690         error = ENOMEM;
  691         goto out;
  692     }
  693     hdr = (Elf_Ehdr *)firstpage;
  694     error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0,
  695                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  696                     &resid, td);
  697     nbytes = PAGE_SIZE - resid;
  698     if (error)
  699         goto out;
  700 
  701     if (!IS_ELF(*hdr)) {
  702         error = ENOEXEC;
  703         goto out;
  704     }
  705 
  706     if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
  707       || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
  708         link_elf_error(filename, "Unsupported file layout");
  709         error = ENOEXEC;
  710         goto out;
  711     }
  712     if (hdr->e_ident[EI_VERSION] != EV_CURRENT
  713       || hdr->e_version != EV_CURRENT) {
  714         link_elf_error(filename, "Unsupported file version");
  715         error = ENOEXEC;
  716         goto out;
  717     }
  718     if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) {
  719         error = ENOSYS;
  720         goto out;
  721     }
  722     if (hdr->e_machine != ELF_TARG_MACH) {
  723         link_elf_error(filename, "Unsupported machine");
  724         error = ENOEXEC;
  725         goto out;
  726     }
  727 
  728     /*
  729      * We rely on the program header being in the first page.  This is
  730      * not strictly required by the ABI specification, but it seems to
  731      * always true in practice.  And, it simplifies things considerably.
  732      */
  733     if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) &&
  734           (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) &&
  735           (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes)))
  736         link_elf_error(filename, "Unreadable program headers");
  737 
  738     /*
  739      * Scan the program header entries, and save key information.
  740      *
  741      * We rely on there being exactly two load segments, text and data,
  742      * in that order.
  743      */
  744     phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff);
  745     phlimit = phdr + hdr->e_phnum;
  746     nsegs = 0;
  747     phdyn = NULL;
  748     phphdr = NULL;
  749     while (phdr < phlimit) {
  750         switch (phdr->p_type) {
  751 
  752         case PT_LOAD:
  753             if (nsegs == MAXSEGS) {
  754                 link_elf_error(filename, "Too many sections");
  755                 error = ENOEXEC;
  756                 goto out;
  757             }
  758             /*
  759              * XXX: We just trust they come in right order ??
  760              */
  761             segs[nsegs] = phdr;
  762             ++nsegs;
  763             break;
  764 
  765         case PT_PHDR:
  766             phphdr = phdr;
  767             break;
  768 
  769         case PT_DYNAMIC:
  770             phdyn = phdr;
  771             break;
  772 
  773         case PT_INTERP:
  774             error = ENOSYS;
  775             goto out;
  776         }
  777 
  778         ++phdr;
  779     }
  780     if (phdyn == NULL) {
  781         link_elf_error(filename, "Object is not dynamically-linked");
  782         error = ENOEXEC;
  783         goto out;
  784     }
  785     if (nsegs == 0) {
  786         link_elf_error(filename, "No sections");
  787         error = ENOEXEC;
  788         goto out;
  789     }
  790 
  791     /*
  792      * Allocate the entire address space of the object, to stake out our
  793      * contiguous region, and to establish the base address for relocation.
  794      */
  795     base_offset = trunc_page(segs[0]->p_offset);
  796     base_vaddr = trunc_page(segs[0]->p_vaddr);
  797     base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 
  798         segs[nsegs - 1]->p_memsz);
  799     mapsize = base_vlimit - base_vaddr;
  800 
  801     lf = linker_make_file(filename, &link_elf_class);
  802     if (!lf) {
  803         error = ENOMEM;
  804         goto out;
  805     }
  806 
  807     ef = (elf_file_t) lf;
  808 #ifdef SPARSE_MAPPING
  809     ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
  810     if (ef->object == NULL) {
  811         error = ENOMEM;
  812         goto out;
  813     }
  814     ef->address = (caddr_t) vm_map_min(kernel_map);
  815     error = vm_map_find(kernel_map, ef->object, 0,
  816                         (vm_offset_t *) &ef->address,
  817                         mapsize, 1,
  818                         VM_PROT_ALL, VM_PROT_ALL, 0);
  819     if (error) {
  820         vm_object_deallocate(ef->object);
  821         ef->object = 0;
  822         goto out;
  823     }
  824 #else
  825     ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
  826     if (!ef->address) {
  827         error = ENOMEM;
  828         goto out;
  829     }
  830 #endif
  831     mapbase = ef->address;
  832 
  833     /*
  834      * Read the text and data sections and zero the bss.
  835      */
  836     for (i = 0; i < nsegs; i++) {
  837         caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr;
  838         error = vn_rdwr(UIO_READ, nd.ni_vp,
  839                         segbase, segs[i]->p_filesz, segs[i]->p_offset,
  840                         UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  841                         &resid, td);
  842         if (error) {
  843             goto out;
  844         }
  845         bzero(segbase + segs[i]->p_filesz,
  846               segs[i]->p_memsz - segs[i]->p_filesz);
  847 
  848 #ifdef SPARSE_MAPPING
  849         /*
  850          * Wire down the pages
  851          */
  852         error = vm_map_wire(kernel_map,
  853                     (vm_offset_t) segbase,
  854                     (vm_offset_t) segbase + segs[i]->p_memsz,
  855                     VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
  856         if (error != KERN_SUCCESS) {
  857             error = ENOMEM;
  858             goto out;
  859         }
  860 #endif
  861     }
  862 
  863 #ifdef GPROF
  864     /* Update profiling information with the new text segment. */
  865     mtx_lock(&Giant);
  866     kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
  867         segs[0]->p_memsz));
  868     mtx_unlock(&Giant);
  869 #endif
  870 
  871     ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
  872 
  873     lf->address = ef->address;
  874     lf->size = mapsize;
  875 
  876     error = parse_dynamic(ef);
  877     if (error)
  878         goto out;
  879     error = parse_dpcpu(ef);
  880     if (error)
  881         goto out;
  882 #ifdef VIMAGE
  883     error = parse_vnet(ef);
  884     if (error)
  885         goto out;
  886 #endif
  887     link_elf_reloc_local(lf);
  888 
  889     VOP_UNLOCK(nd.ni_vp, 0);
  890     error = linker_load_dependencies(lf);
  891     vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
  892     if (error)
  893         goto out;
  894 #if 0   /* this will be more trouble than it's worth for now */
  895     for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) {
  896         if (dp->d_tag != DT_NEEDED)
  897             continue;
  898         modname = ef->strtab + dp->d_un.d_val;
  899         error = linker_load_module(modname, lf);
  900         if (error)
  901             goto out;
  902     }
  903 #endif
  904     error = relocate_file(ef);
  905     if (error)
  906         goto out;
  907 
  908     /* Try and load the symbol table if it's present.  (you can strip it!) */
  909     nbytes = hdr->e_shnum * hdr->e_shentsize;
  910     if (nbytes == 0 || hdr->e_shoff == 0)
  911         goto nosyms;
  912     shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO);
  913     if (shdr == NULL) {
  914         error = ENOMEM;
  915         goto out;
  916     }
  917     error = vn_rdwr(UIO_READ, nd.ni_vp,
  918                     (caddr_t)shdr, nbytes, hdr->e_shoff,
  919                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  920                     &resid, td);
  921     if (error)
  922         goto out;
  923     symtabindex = -1;
  924     symstrindex = -1;
  925     for (i = 0; i < hdr->e_shnum; i++) {
  926         if (shdr[i].sh_type == SHT_SYMTAB) {
  927             symtabindex = i;
  928             symstrindex = shdr[i].sh_link;
  929         }
  930     }
  931     if (symtabindex < 0 || symstrindex < 0)
  932         goto nosyms;
  933 
  934     symcnt = shdr[symtabindex].sh_size;
  935     ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK);
  936     strcnt = shdr[symstrindex].sh_size;
  937     ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK);
  938 
  939     if (ef->symbase == NULL || ef->strbase == NULL) {
  940         error = ENOMEM;
  941         goto out;
  942     }
  943     error = vn_rdwr(UIO_READ, nd.ni_vp,
  944                     ef->symbase, symcnt, shdr[symtabindex].sh_offset,
  945                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  946                     &resid, td);
  947     if (error)
  948         goto out;
  949     error = vn_rdwr(UIO_READ, nd.ni_vp,
  950                     ef->strbase, strcnt, shdr[symstrindex].sh_offset,
  951                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  952                     &resid, td);
  953     if (error)
  954         goto out;
  955 
  956     ef->ddbsymcnt = symcnt / sizeof(Elf_Sym);
  957     ef->ddbsymtab = (const Elf_Sym *)ef->symbase;
  958     ef->ddbstrcnt = strcnt;
  959     ef->ddbstrtab = ef->strbase;
  960 
  961     error = link_elf_link_common_finish(lf);
  962     if (error)
  963         goto out;
  964 
  965 nosyms:
  966 
  967     *result = lf;
  968 
  969 out:
  970     if (error && lf)
  971         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  972     if (shdr)
  973         free(shdr, M_LINKER);
  974     if (firstpage)
  975         free(firstpage, M_LINKER);
  976     VOP_UNLOCK(nd.ni_vp, 0);
  977     vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  978     VFS_UNLOCK_GIANT(vfslocked);
  979 
  980     return error;
  981 }
  982 
  983 Elf_Addr
  984 elf_relocaddr(linker_file_t lf, Elf_Addr x)
  985 {
  986     elf_file_t ef;
  987 
  988     ef = (elf_file_t)lf;
  989     if (x >= ef->pcpu_start && x < ef->pcpu_stop)
  990         return ((x - ef->pcpu_start) + ef->pcpu_base);
  991 #ifdef VIMAGE
  992     if (x >= ef->vnet_start && x < ef->vnet_stop)
  993         return ((x - ef->vnet_start) + ef->vnet_base);
  994 #endif
  995     return (x);
  996 }
  997 
  998 
  999 static void
 1000 link_elf_unload_file(linker_file_t file)
 1001 {
 1002     elf_file_t ef = (elf_file_t) file;
 1003 
 1004     if (ef->pcpu_base) {
 1005         dpcpu_free((void *)ef->pcpu_base, ef->pcpu_stop - ef->pcpu_start);
 1006     }
 1007 #ifdef VIMAGE
 1008     if (ef->vnet_base) {
 1009         vnet_data_free((void *)ef->vnet_base, ef->vnet_stop - ef->vnet_start);
 1010     }
 1011 #endif
 1012 #ifdef GDB
 1013     if (ef->gdb.l_ld) {
 1014         GDB_STATE(RT_DELETE);
 1015         free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER);
 1016         link_elf_delete_gdb(&ef->gdb);
 1017         GDB_STATE(RT_CONSISTENT);
 1018     }
 1019 #endif
 1020 
 1021     /* Notify MD code that a module is being unloaded. */
 1022     elf_cpu_unload_file(file);
 1023 
 1024     if (ef->preloaded) {
 1025         link_elf_unload_preload(file);
 1026         return;
 1027     }
 1028 
 1029 #ifdef SPARSE_MAPPING
 1030     if (ef->object) {
 1031         vm_map_remove(kernel_map, (vm_offset_t) ef->address,
 1032                       (vm_offset_t) ef->address
 1033                       + (ef->object->size << PAGE_SHIFT));
 1034     }
 1035 #else
 1036     if (ef->address)
 1037         free(ef->address, M_LINKER);
 1038 #endif
 1039     if (ef->symbase)
 1040         free(ef->symbase, M_LINKER);
 1041     if (ef->strbase)
 1042         free(ef->strbase, M_LINKER);
 1043     if (ef->ctftab)
 1044         free(ef->ctftab, M_LINKER);
 1045     if (ef->ctfoff)
 1046         free(ef->ctfoff, M_LINKER);
 1047     if (ef->typoff)
 1048         free(ef->typoff, M_LINKER);
 1049 }
 1050 
 1051 static void
 1052 link_elf_unload_preload(linker_file_t file)
 1053 {
 1054     if (file->filename)
 1055         preload_delete_name(file->filename);
 1056 }
 1057 
 1058 static const char *
 1059 symbol_name(elf_file_t ef, Elf_Size r_info)
 1060 {
 1061     const Elf_Sym *ref;
 1062 
 1063     if (ELF_R_SYM(r_info)) {
 1064         ref = ef->symtab + ELF_R_SYM(r_info);
 1065         return ef->strtab + ref->st_name;
 1066     } else
 1067         return NULL;
 1068 }
 1069 
 1070 static int
 1071 relocate_file(elf_file_t ef)
 1072 {
 1073     const Elf_Rel *rellim;
 1074     const Elf_Rel *rel;
 1075     const Elf_Rela *relalim;
 1076     const Elf_Rela *rela;
 1077     const char *symname;
 1078 
 1079     /* Perform relocations without addend if there are any: */
 1080     rel = ef->rel;
 1081     if (rel) {
 1082         rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
 1083         while (rel < rellim) {
 1084             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
 1085                           elf_lookup)) {
 1086                 symname = symbol_name(ef, rel->r_info);
 1087                 printf("link_elf: symbol %s undefined\n", symname);
 1088                 return ENOENT;
 1089             }
 1090             rel++;
 1091         }
 1092     }
 1093 
 1094     /* Perform relocations with addend if there are any: */
 1095     rela = ef->rela;
 1096     if (rela) {
 1097         relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
 1098         while (rela < relalim) {
 1099             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
 1100                           elf_lookup)) {
 1101                 symname = symbol_name(ef, rela->r_info);
 1102                 printf("link_elf: symbol %s undefined\n", symname);
 1103                 return ENOENT;
 1104             }
 1105             rela++;
 1106         }
 1107     }
 1108 
 1109     /* Perform PLT relocations without addend if there are any: */
 1110     rel = ef->pltrel;
 1111     if (rel) {
 1112         rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
 1113         while (rel < rellim) {
 1114             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
 1115                           elf_lookup)) {
 1116                 symname = symbol_name(ef, rel->r_info);
 1117                 printf("link_elf: symbol %s undefined\n", symname);
 1118                 return ENOENT;
 1119             }
 1120             rel++;
 1121         }
 1122     }
 1123 
 1124     /* Perform relocations with addend if there are any: */
 1125     rela = ef->pltrela;
 1126     if (rela) {
 1127         relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
 1128         while (rela < relalim) {
 1129             if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
 1130                           elf_lookup)) {
 1131                 symname = symbol_name(ef, rela->r_info);
 1132                 printf("link_elf: symbol %s undefined\n", symname);
 1133                 return ENOENT;
 1134             }
 1135             rela++;
 1136         }
 1137     }
 1138 
 1139     return 0;
 1140 }
 1141 
 1142 /*
 1143  * Hash function for symbol table lookup.  Don't even think about changing
 1144  * this.  It is specified by the System V ABI.
 1145  */
 1146 static unsigned long
 1147 elf_hash(const char *name)
 1148 {
 1149     const unsigned char *p = (const unsigned char *) name;
 1150     unsigned long h = 0;
 1151     unsigned long g;
 1152 
 1153     while (*p != '\0') {
 1154         h = (h << 4) + *p++;
 1155         if ((g = h & 0xf0000000) != 0)
 1156             h ^= g >> 24;
 1157         h &= ~g;
 1158     }
 1159     return h;
 1160 }
 1161 
 1162 static int
 1163 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym)
 1164 {
 1165     elf_file_t ef = (elf_file_t) lf;
 1166     unsigned long symnum;
 1167     const Elf_Sym* symp;
 1168     const char *strp;
 1169     unsigned long hash;
 1170     int i;
 1171 
 1172     /* If we don't have a hash, bail. */
 1173     if (ef->buckets == NULL || ef->nbuckets == 0) {
 1174         printf("link_elf_lookup_symbol: missing symbol hash table\n");
 1175         return ENOENT;
 1176     }
 1177 
 1178     /* First, search hashed global symbols */
 1179     hash = elf_hash(name);
 1180     symnum = ef->buckets[hash % ef->nbuckets];
 1181 
 1182     while (symnum != STN_UNDEF) {
 1183         if (symnum >= ef->nchains) {
 1184             printf("link_elf_lookup_symbol: corrupt symbol table\n");
 1185             return ENOENT;
 1186         }
 1187 
 1188         symp = ef->symtab + symnum;
 1189         if (symp->st_name == 0) {
 1190             printf("link_elf_lookup_symbol: corrupt symbol table\n");
 1191             return ENOENT;
 1192         }
 1193 
 1194         strp = ef->strtab + symp->st_name;
 1195 
 1196         if (strcmp(name, strp) == 0) {
 1197             if (symp->st_shndx != SHN_UNDEF ||
 1198                 (symp->st_value != 0 &&
 1199                  ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
 1200                 *sym = (c_linker_sym_t) symp;
 1201                 return 0;
 1202             } else
 1203                 return ENOENT;
 1204         }
 1205 
 1206         symnum = ef->chains[symnum];
 1207     }
 1208 
 1209     /* If we have not found it, look at the full table (if loaded) */
 1210     if (ef->symtab == ef->ddbsymtab)
 1211         return ENOENT;
 1212 
 1213     /* Exhaustive search */
 1214     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1215         strp = ef->ddbstrtab + symp->st_name;
 1216         if (strcmp(name, strp) == 0) {
 1217             if (symp->st_shndx != SHN_UNDEF ||
 1218                 (symp->st_value != 0 &&
 1219                  ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
 1220                 *sym = (c_linker_sym_t) symp;
 1221                 return 0;
 1222             } else
 1223                 return ENOENT;
 1224         }
 1225     }
 1226 
 1227     return ENOENT;
 1228 }
 1229 
 1230 static int
 1231 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval)
 1232 {
 1233         elf_file_t ef = (elf_file_t) lf;
 1234         const Elf_Sym* es = (const Elf_Sym*) sym;
 1235 
 1236         if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
 1237             symval->name = ef->strtab + es->st_name;
 1238             symval->value = (caddr_t) ef->address + es->st_value;
 1239             symval->size = es->st_size;
 1240             return 0;
 1241         }
 1242         if (ef->symtab == ef->ddbsymtab)
 1243             return ENOENT;
 1244         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 1245             symval->name = ef->ddbstrtab + es->st_name;
 1246             symval->value = (caddr_t) ef->address + es->st_value;
 1247             symval->size = es->st_size;
 1248             return 0;
 1249         }
 1250         return ENOENT;
 1251 }
 1252 
 1253 static int
 1254 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 1255                        c_linker_sym_t* sym, long* diffp)
 1256 {
 1257         elf_file_t ef = (elf_file_t) lf;
 1258         u_long off = (uintptr_t) (void *) value;
 1259         u_long diff = off;
 1260         u_long st_value;
 1261         const Elf_Sym* es;
 1262         const Elf_Sym* best = 0;
 1263         int i;
 1264 
 1265         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 1266                 if (es->st_name == 0)
 1267                         continue;
 1268                 st_value = es->st_value + (uintptr_t) (void *) ef->address;
 1269                 if (off >= st_value) {
 1270                         if (off - st_value < diff) {
 1271                                 diff = off - st_value;
 1272                                 best = es;
 1273                                 if (diff == 0)
 1274                                         break;
 1275                         } else if (off - st_value == diff) {
 1276                                 best = es;
 1277                         }
 1278                 }
 1279         }
 1280         if (best == 0)
 1281                 *diffp = off;
 1282         else
 1283                 *diffp = diff;
 1284         *sym = (c_linker_sym_t) best;
 1285 
 1286         return 0;
 1287 }
 1288 
 1289 /*
 1290  * Look up a linker set on an ELF system.
 1291  */
 1292 static int
 1293 link_elf_lookup_set(linker_file_t lf, const char *name,
 1294                     void ***startp, void ***stopp, int *countp)
 1295 {
 1296         c_linker_sym_t sym;
 1297         linker_symval_t symval;
 1298         char *setsym;
 1299         void **start, **stop;
 1300         int len, error = 0, count;
 1301 
 1302         len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
 1303         setsym = malloc(len, M_LINKER, M_WAITOK);
 1304         if (setsym == NULL)
 1305                 return ENOMEM;
 1306 
 1307         /* get address of first entry */
 1308         snprintf(setsym, len, "%s%s", "__start_set_", name);
 1309         error = link_elf_lookup_symbol(lf, setsym, &sym);
 1310         if (error)
 1311                 goto out;
 1312         link_elf_symbol_values(lf, sym, &symval);
 1313         if (symval.value == 0) {
 1314                 error = ESRCH;
 1315                 goto out;
 1316         }
 1317         start = (void **)symval.value;
 1318 
 1319         /* get address of last entry */
 1320         snprintf(setsym, len, "%s%s", "__stop_set_", name);
 1321         error = link_elf_lookup_symbol(lf, setsym, &sym);
 1322         if (error)
 1323                 goto out;
 1324         link_elf_symbol_values(lf, sym, &symval);
 1325         if (symval.value == 0) {
 1326                 error = ESRCH;
 1327                 goto out;
 1328         }
 1329         stop = (void **)symval.value;
 1330 
 1331         /* and the number of entries */
 1332         count = stop - start;
 1333 
 1334         /* and copy out */
 1335         if (startp)
 1336                 *startp = start;
 1337         if (stopp)
 1338                 *stopp = stop;
 1339         if (countp)
 1340                 *countp = count;
 1341 
 1342 out:
 1343         free(setsym, M_LINKER);
 1344         return error;
 1345 }
 1346 
 1347 static int
 1348 link_elf_each_function_name(linker_file_t file,
 1349   int (*callback)(const char *, void *), void *opaque) {
 1350     elf_file_t ef = (elf_file_t)file;
 1351     const Elf_Sym* symp;
 1352     int i, error;
 1353         
 1354     /* Exhaustive search */
 1355     for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1356         if (symp->st_value != 0 &&
 1357             ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1358                 error = callback(ef->ddbstrtab + symp->st_name, opaque);
 1359                 if (error)
 1360                     return (error);
 1361         }
 1362     }
 1363     return (0);
 1364 }
 1365 
 1366 static int
 1367 link_elf_each_function_nameval(linker_file_t file,
 1368     linker_function_nameval_callback_t callback, void *opaque)
 1369 {
 1370         linker_symval_t symval;
 1371         elf_file_t ef = (elf_file_t)file;
 1372         const Elf_Sym* symp;
 1373         int i, error;
 1374 
 1375         /* Exhaustive search */
 1376         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 1377                 if (symp->st_value != 0 &&
 1378                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
 1379                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
 1380                         if (error)
 1381                                 return (error);
 1382                         error = callback(file, i, &symval, opaque);
 1383                         if (error)
 1384                                 return (error);
 1385                 }
 1386         }
 1387         return (0);
 1388 }
 1389 
 1390 #ifdef __ia64__
 1391 /*
 1392  * Each KLD has its own GP. The GP value for each load module is given by
 1393  * DT_PLTGOT on ia64. We need GP to construct function descriptors, but
 1394  * don't have direct access to the ELF file structure. The link_elf_get_gp()
 1395  * function returns the GP given a pointer to a generic linker file struct.
 1396  */
 1397 Elf_Addr
 1398 link_elf_get_gp(linker_file_t lf)
 1399 {
 1400         elf_file_t ef = (elf_file_t)lf;
 1401         return (Elf_Addr)ef->got;
 1402 }
 1403 #endif
 1404 
 1405 const Elf_Sym *
 1406 elf_get_sym(linker_file_t lf, Elf_Size symidx)
 1407 {
 1408         elf_file_t ef = (elf_file_t)lf;
 1409 
 1410         if (symidx >= ef->nchains)
 1411                 return (NULL);
 1412         return (ef->symtab + symidx);
 1413 }
 1414 
 1415 const char *
 1416 elf_get_symname(linker_file_t lf, Elf_Size symidx)
 1417 {
 1418         elf_file_t ef = (elf_file_t)lf;
 1419         const Elf_Sym *sym;
 1420 
 1421         if (symidx >= ef->nchains)
 1422                 return (NULL);
 1423         sym = ef->symtab + symidx;
 1424         return (ef->strtab + sym->st_name);
 1425 }
 1426 
 1427 /*
 1428  * Symbol lookup function that can be used when the symbol index is known (ie
 1429  * in relocations). It uses the symbol index instead of doing a fully fledged
 1430  * hash table based lookup when such is valid. For example for local symbols.
 1431  * This is not only more efficient, it's also more correct. It's not always
 1432  * the case that the symbol can be found through the hash table.
 1433  */
 1434 static Elf_Addr
 1435 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
 1436 {
 1437         elf_file_t ef = (elf_file_t)lf;
 1438         const Elf_Sym *sym;
 1439         const char *symbol;
 1440 
 1441         /* Don't even try to lookup the symbol if the index is bogus. */
 1442         if (symidx >= ef->nchains)
 1443                 return (0);
 1444 
 1445         sym = ef->symtab + symidx;
 1446 
 1447         /*
 1448          * Don't do a full lookup when the symbol is local. It may even
 1449          * fail because it may not be found through the hash table.
 1450          */
 1451         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
 1452                 /* Force lookup failure when we have an insanity. */
 1453                 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
 1454                         return (0);
 1455                 return ((Elf_Addr)ef->address + sym->st_value);
 1456         }
 1457 
 1458         /*
 1459          * XXX we can avoid doing a hash table based lookup for global
 1460          * symbols as well. This however is not always valid, so we'll
 1461          * just do it the hard way for now. Performance tweaks can
 1462          * always be added.
 1463          */
 1464 
 1465         symbol = ef->strtab + sym->st_name;
 1466 
 1467         /* Force a lookup failure if the symbol name is bogus. */
 1468         if (*symbol == 0)
 1469                 return (0);
 1470 
 1471         return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
 1472 }
 1473 
 1474 static void
 1475 link_elf_reloc_local(linker_file_t lf)
 1476 {
 1477     const Elf_Rel *rellim;
 1478     const Elf_Rel *rel;
 1479     const Elf_Rela *relalim;
 1480     const Elf_Rela *rela;
 1481     elf_file_t ef = (elf_file_t)lf;
 1482 
 1483     /* Perform relocations without addend if there are any: */
 1484     if ((rel = ef->rel) != NULL) {
 1485         rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
 1486         while (rel < rellim) {
 1487             elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL,
 1488                             elf_lookup);
 1489             rel++;
 1490         }
 1491     }
 1492 
 1493     /* Perform relocations with addend if there are any: */
 1494     if ((rela = ef->rela) != NULL) {
 1495         relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
 1496         while (rela < relalim) {
 1497             elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA,
 1498                             elf_lookup);
 1499             rela++;
 1500         }
 1501     }
 1502 }
 1503 
 1504 static long
 1505 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
 1506 {
 1507     elf_file_t ef = (elf_file_t)lf;
 1508     
 1509     *symtab = ef->ddbsymtab;
 1510     
 1511     if (*symtab == NULL)
 1512         return (0);
 1513 
 1514     return (ef->ddbsymcnt);
 1515 }
 1516     
 1517 static long
 1518 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
 1519 {
 1520     elf_file_t ef = (elf_file_t)lf;
 1521 
 1522     *strtab = ef->ddbstrtab;
 1523 
 1524     if (*strtab == NULL)
 1525         return (0);
 1526 
 1527     return (ef->ddbstrcnt);
 1528 }

Cache object: f96cbde4033370c160de2b0f04f875dd


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


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