sys/kern/link_elf_obj.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 1998-2000 Doug Rabson
   5  * Copyright (c) 2004 Peter Wemm
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include "opt_ddb.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/lock.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/mount.h>
  42 #include <sys/proc.h>
  43 #include <sys/namei.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/vnode.h>
  46 #include <sys/linker.h>
  47
  48 #include <machine/elf.h>
  49
  50 #include <net/vnet.h>
  51
  52 #include <security/mac/mac_framework.h>
  53
  54 #include <vm/vm.h>
  55 #include <vm/vm_param.h>
  56 #include <vm/vm_object.h>
  57 #include <vm/vm_kern.h>
  58 #include <vm/vm_extern.h>
  59 #include <vm/pmap.h>
  60 #include <vm/vm_map.h>
  61
  62 #include <sys/link_elf.h>
  63
  64 #ifdef DDB_CTF
  65 #include <sys/zlib.h>
  66 #endif
  67
  68 #include "linker_if.h"
  69
  70 typedef struct {
  71         void            *addr;
  72         Elf_Off         size;
  73         int             flags;
  74         int             sec;    /* Original section */
  75         char            *name;
  76 } Elf_progent;
  77
  78 typedef struct {
  79         Elf_Rel         *rel;
  80         int             nrel;
  81         int             sec;
  82 } Elf_relent;
  83
  84 typedef struct {
  85         Elf_Rela        *rela;
  86         int             nrela;
  87         int             sec;
  88 } Elf_relaent;
  89
  90
  91 typedef struct elf_file {
  92         struct linker_file lf;          /* Common fields */
  93
  94         int             preloaded;
  95         caddr_t         address;        /* Relocation address */
  96         vm_object_t     object;         /* VM object to hold file pages */
  97         Elf_Shdr        *e_shdr;
  98
  99         Elf_progent     *progtab;
 100         int             nprogtab;
 101
 102         Elf_relaent     *relatab;
 103         int             nrelatab;
 104
 105         Elf_relent      *reltab;
 106         int             nreltab;
 107
 108         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 109         long            ddbsymcnt;      /* Number of symbols */
 110         caddr_t         ddbstrtab;      /* String table */
 111         long            ddbstrcnt;      /* number of bytes in string table */
 112
 113         caddr_t         shstrtab;       /* Section name string table */
 114         long            shstrcnt;       /* number of bytes in string table */
 115
 116         caddr_t         ctftab;         /* CTF table */
 117         long            ctfcnt;         /* number of bytes in CTF table */
 118         caddr_t         ctfoff;         /* CTF offset table */
 119         caddr_t         typoff;         /* Type offset table */
 120         long            typlen;         /* Number of type entries. */
 121
 122 } *elf_file_t;
 123
 124 #include <kern/kern_ctf.c>
 125
 126 static int      link_elf_link_preload(linker_class_t cls,
 127                     const char *, linker_file_t *);
 128 static int      link_elf_link_preload_finish(linker_file_t);
 129 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 130 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 131                     c_linker_sym_t *);
 132 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 133                     linker_symval_t *);
 134 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 135                     c_linker_sym_t *sym, long *diffp);
 136
 137 static void     link_elf_unload_file(linker_file_t);
 138 static int      link_elf_lookup_set(linker_file_t, const char *,
 139                     void ***, void ***, int *);
 140 static int      link_elf_each_function_name(linker_file_t,
 141                     int (*)(const char *, void *), void *);
 142 static int      link_elf_each_function_nameval(linker_file_t,
 143                                 linker_function_nameval_callback_t,
 144                                 void *);
 145 static int      link_elf_reloc_local(linker_file_t);
 146 static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
 147 static long     link_elf_strtab_get(linker_file_t, caddr_t *);
 148
 149 static int      elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
 150                     Elf_Addr *);
 151
 152 static kobj_method_t link_elf_methods[] = {
 153         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 154         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 155         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 156         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 157         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 158         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 159         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 160         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 161         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 162         KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
 163         KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
 164         KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
 165         KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
 166         { 0, 0 }
 167 };
 168
 169 static struct linker_class link_elf_class = {
 170 #if ELF_TARG_CLASS == ELFCLASS32
 171         "elf32_obj",
 172 #else
 173         "elf64_obj",
 174 #endif
 175         link_elf_methods, sizeof(struct elf_file)
 176 };
 177
 178 static int      relocate_file(elf_file_t ef);
 179 static void     elf_obj_cleanup_globals_cache(elf_file_t);
 180
 181 static void
 182 link_elf_error(const char *filename, const char *s)
 183 {
 184         if (filename == NULL)
 185                 printf("kldload: %s\n", s);
 186         else
 187                 printf("kldload: %s: %s\n", filename, s);
 188 }
 189
 190 static void
 191 link_elf_init(void *arg)
 192 {
 193
 194         linker_add_class(&link_elf_class);
 195 }
 196
 197 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
 198
 199 static int
 200 link_elf_link_preload(linker_class_t cls, const char *filename,
 201     linker_file_t *result)
 202 {
 203         Elf_Ehdr *hdr;
 204         Elf_Shdr *shdr;
 205         Elf_Sym *es;
 206         void *modptr, *baseptr, *sizeptr;
 207         char *type;
 208         elf_file_t ef;
 209         linker_file_t lf;
 210         Elf_Addr off;
 211         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 212
 213         /* Look to see if we have the file preloaded */
 214         modptr = preload_search_by_name(filename);
 215         if (modptr == NULL)
 216                 return ENOENT;
 217
 218         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 219         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 220         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 221         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 222             MODINFOMD_ELFHDR);
 223         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 224             MODINFOMD_SHDR);
 225         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 226             " obj module") != 0 &&
 227             strcmp(type, "elf obj module") != 0)) {
 228                 return (EFTYPE);
 229         }
 230         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 231             shdr == NULL)
 232                 return (EINVAL);
 233
 234         lf = linker_make_file(filename, &link_elf_class);
 235         if (lf == NULL)
 236                 return (ENOMEM);
 237
 238         ef = (elf_file_t)lf;
 239         ef->preloaded = 1;
 240         ef->address = *(caddr_t *)baseptr;
 241         lf->address = *(caddr_t *)baseptr;
 242         lf->size = *(size_t *)sizeptr;
 243
 244         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 245             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 246             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 247             hdr->e_version != EV_CURRENT ||
 248             hdr->e_type != ET_REL ||
 249             hdr->e_machine != ELF_TARG_MACH) {
 250                 error = EFTYPE;
 251                 goto out;
 252         }
 253         ef->e_shdr = shdr;
 254
 255         /* Scan the section header for information and table sizing. */
 256         symtabindex = -1;
 257         symstrindex = -1;
 258         for (i = 0; i < hdr->e_shnum; i++) {
 259                 switch (shdr[i].sh_type) {
 260                 case SHT_PROGBITS:
 261                 case SHT_NOBITS:
 262 #ifdef __amd64__
 263                 case SHT_X86_64_UNWIND:
 264 #endif
 265                         /* Ignore sections not loaded by the loader. */
 266                         if (shdr[i].sh_addr == 0)
 267                                 break;
 268                         ef->nprogtab++;
 269                         break;
 270                 case SHT_SYMTAB:
 271                         symtabindex = i;
 272                         symstrindex = shdr[i].sh_link;
 273                         break;
 274                 case SHT_REL:
 275                         ef->nreltab++;
 276                         break;
 277                 case SHT_RELA:
 278                         ef->nrelatab++;
 279                         break;
 280                 }
 281         }
 282
 283         shstrindex = hdr->e_shstrndx;
 284         if (ef->nprogtab == 0 || symstrindex < 0 ||
 285             symstrindex >= hdr->e_shnum ||
 286             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 287             shstrindex >= hdr->e_shnum ||
 288             shdr[shstrindex].sh_type != SHT_STRTAB) {
 289                 printf("%s: bad/missing section headers\n", filename);
 290                 error = ENOEXEC;
 291                 goto out;
 292         }
 293
 294         /* Allocate space for tracking the load chunks */
 295         if (ef->nprogtab != 0)
 296                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 297                     M_LINKER, M_WAITOK | M_ZERO);
 298         if (ef->nreltab != 0)
 299                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 300                     M_LINKER, M_WAITOK | M_ZERO);
 301         if (ef->nrelatab != 0)
 302                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 303                     M_LINKER, M_WAITOK | M_ZERO);
 304         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 305             (ef->nreltab != 0 && ef->reltab == NULL) ||
 306             (ef->nrelatab != 0 && ef->relatab == NULL)) {
 307                 error = ENOMEM;
 308                 goto out;
 309         }
 310
 311         /* XXX, relocate the sh_addr fields saved by the loader. */
 312         off = 0;
 313         for (i = 0; i < hdr->e_shnum; i++) {
 314                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 315                         off = shdr[i].sh_addr;
 316         }
 317         for (i = 0; i < hdr->e_shnum; i++) {
 318                 if (shdr[i].sh_addr != 0)
 319                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 320                             (Elf_Addr)ef->address;
 321         }
 322
 323         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 324         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 325         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 326         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 327         ef->shstrcnt = shdr[shstrindex].sh_size;
 328         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 329
 330         /* Now fill out progtab and the relocation tables. */
 331         pb = 0;
 332         rl = 0;
 333         ra = 0;
 334         for (i = 0; i < hdr->e_shnum; i++) {
 335                 switch (shdr[i].sh_type) {
 336                 case SHT_PROGBITS:
 337                 case SHT_NOBITS:
 338 #ifdef __amd64__
 339                 case SHT_X86_64_UNWIND:
 340 #endif
 341                         if (shdr[i].sh_addr == 0)
 342                                 break;
 343                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 344                         if (shdr[i].sh_type == SHT_PROGBITS)
 345                                 ef->progtab[pb].name = "<<PROGBITS>>";
 346 #ifdef __amd64__
 347                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 348                                 ef->progtab[pb].name = "<<UNWIND>>";
 349 #endif
 350                         else
 351                                 ef->progtab[pb].name = "<<NOBITS>>";
 352                         ef->progtab[pb].size = shdr[i].sh_size;
 353                         ef->progtab[pb].sec = i;
 354                         if (ef->shstrtab && shdr[i].sh_name != 0)
 355                                 ef->progtab[pb].name =
 356                                     ef->shstrtab + shdr[i].sh_name;
 357                         if (ef->progtab[pb].name != NULL &&
 358                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 359                                 void *dpcpu;
 360
 361                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
 362                                 if (dpcpu == NULL) {
 363                                         error = ENOSPC;
 364                                         goto out;
 365                                 }
 366                                 memcpy(dpcpu, ef->progtab[pb].addr,
 367                                     ef->progtab[pb].size);
 368                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
 369                                 ef->progtab[pb].addr = dpcpu;
 370 #ifdef VIMAGE
 371                         } else if (ef->progtab[pb].name != NULL &&
 372                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 373                                 void *vnet_data;
 374
 375                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
 376                                 if (vnet_data == NULL) {
 377                                         error = ENOSPC;
 378                                         goto out;
 379                                 }
 380                                 memcpy(vnet_data, ef->progtab[pb].addr,
 381                                     ef->progtab[pb].size);
 382                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
 383                                 ef->progtab[pb].addr = vnet_data;
 384 #endif
 385                         } else if (ef->progtab[pb].name != NULL &&
 386                             !strcmp(ef->progtab[pb].name, ".ctors")) {
 387                                 lf->ctors_addr = ef->progtab[pb].addr;
 388                                 lf->ctors_size = shdr[i].sh_size;
 389                         }
 390
 391                         /* Update all symbol values with the offset. */
 392                         for (j = 0; j < ef->ddbsymcnt; j++) {
 393                                 es = &ef->ddbsymtab[j];
 394                                 if (es->st_shndx != i)
 395                                         continue;
 396                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 397                         }
 398                         pb++;
 399                         break;
 400                 case SHT_REL:
 401                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 402                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 403                         ef->reltab[rl].sec = shdr[i].sh_info;
 404                         rl++;
 405                         break;
 406                 case SHT_RELA:
 407                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 408                         ef->relatab[ra].nrela =
 409                             shdr[i].sh_size / sizeof(Elf_Rela);
 410                         ef->relatab[ra].sec = shdr[i].sh_info;
 411                         ra++;
 412                         break;
 413                 }
 414         }
 415         if (pb != ef->nprogtab) {
 416                 printf("%s: lost progbits\n", filename);
 417                 error = ENOEXEC;
 418                 goto out;
 419         }
 420         if (rl != ef->nreltab) {
 421                 printf("%s: lost reltab\n", filename);
 422                 error = ENOEXEC;
 423                 goto out;
 424         }
 425         if (ra != ef->nrelatab) {
 426                 printf("%s: lost relatab\n", filename);
 427                 error = ENOEXEC;
 428                 goto out;
 429         }
 430
 431         /* Local intra-module relocations */
 432         error = link_elf_reloc_local(lf);
 433         if (error != 0)
 434                 goto out;
 435
 436         *result = lf;
 437         return (0);
 438
 439 out:
 440         /* preload not done this way */
 441         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 442         return (error);
 443 }
 444
 445 static void
 446 link_elf_invoke_ctors(caddr_t addr, size_t size)
 447 {
 448         void (**ctor)(void);
 449         size_t i, cnt;
 450
 451         if (addr == NULL || size == 0)
 452                 return;
 453         cnt = size / sizeof(*ctor);
 454         ctor = (void *)addr;
 455         for (i = 0; i < cnt; i++) {
 456                 if (ctor[i] != NULL)
 457                         (*ctor[i])();
 458         }
 459 }
 460
 461 static int
 462 link_elf_link_preload_finish(linker_file_t lf)
 463 {
 464         elf_file_t ef;
 465         int error;
 466
 467         ef = (elf_file_t)lf;
 468         error = relocate_file(ef);
 469         if (error)
 470                 return error;
 471
 472         /* Notify MD code that a module is being loaded. */
 473         error = elf_cpu_load_file(lf);
 474         if (error)
 475                 return (error);
 476
 477         /* Invoke .ctors */
 478         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 479         return (0);
 480 }
 481
 482 static int
 483 link_elf_load_file(linker_class_t cls, const char *filename,
 484     linker_file_t *result)
 485 {
 486         struct nameidata *nd;
 487         struct thread *td = curthread;  /* XXX */
 488         Elf_Ehdr *hdr;
 489         Elf_Shdr *shdr;
 490         Elf_Sym *es;
 491         int nbytes, i, j;
 492         vm_offset_t mapbase;
 493         size_t mapsize;
 494         int error = 0;
 495         ssize_t resid;
 496         int flags;
 497         elf_file_t ef;
 498         linker_file_t lf;
 499         int symtabindex;
 500         int symstrindex;
 501         int shstrindex;
 502         int nsym;
 503         int pb, rl, ra;
 504         int alignmask;
 505
 506         shdr = NULL;
 507         lf = NULL;
 508         mapsize = 0;
 509         hdr = NULL;
 510
 511         nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
 512         NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 513         flags = FREAD;
 514         error = vn_open(nd, &flags, 0, NULL);
 515         if (error) {
 516                 free(nd, M_TEMP);
 517                 return error;
 518         }
 519         NDFREE(nd, NDF_ONLY_PNBUF);
 520         if (nd->ni_vp->v_type != VREG) {
 521                 error = ENOEXEC;
 522                 goto out;
 523         }
 524 #ifdef MAC
 525         error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
 526         if (error) {
 527                 goto out;
 528         }
 529 #endif
 530
 531         /* Read the elf header from the file. */
 532         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 533         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
 534             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 535             &resid, td);
 536         if (error)
 537                 goto out;
 538         if (resid != 0){
 539                 error = ENOEXEC;
 540                 goto out;
 541         }
 542
 543         if (!IS_ELF(*hdr)) {
 544                 error = ENOEXEC;
 545                 goto out;
 546         }
 547
 548         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 549             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 550                 link_elf_error(filename, "Unsupported file layout");
 551                 error = ENOEXEC;
 552                 goto out;
 553         }
 554         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 555             || hdr->e_version != EV_CURRENT) {
 556                 link_elf_error(filename, "Unsupported file version");
 557                 error = ENOEXEC;
 558                 goto out;
 559         }
 560         if (hdr->e_type != ET_REL) {
 561                 error = ENOSYS;
 562                 goto out;
 563         }
 564         if (hdr->e_machine != ELF_TARG_MACH) {
 565                 link_elf_error(filename, "Unsupported machine");
 566                 error = ENOEXEC;
 567                 goto out;
 568         }
 569
 570         lf = linker_make_file(filename, &link_elf_class);
 571         if (!lf) {
 572                 error = ENOMEM;
 573                 goto out;
 574         }
 575         ef = (elf_file_t) lf;
 576         ef->nprogtab = 0;
 577         ef->e_shdr = 0;
 578         ef->nreltab = 0;
 579         ef->nrelatab = 0;
 580
 581         /* Allocate and read in the section header */
 582         nbytes = hdr->e_shnum * hdr->e_shentsize;
 583         if (nbytes == 0 || hdr->e_shoff == 0 ||
 584             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 585                 error = ENOEXEC;
 586                 goto out;
 587         }
 588         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 589         ef->e_shdr = shdr;
 590         error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
 591             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 592             NOCRED, &resid, td);
 593         if (error)
 594                 goto out;
 595         if (resid) {
 596                 error = ENOEXEC;
 597                 goto out;
 598         }
 599
 600         /* Scan the section header for information and table sizing. */
 601         nsym = 0;
 602         symtabindex = -1;
 603         symstrindex = -1;
 604         for (i = 0; i < hdr->e_shnum; i++) {
 605                 if (shdr[i].sh_size == 0)
 606                         continue;
 607                 switch (shdr[i].sh_type) {
 608                 case SHT_PROGBITS:
 609                 case SHT_NOBITS:
 610 #ifdef __amd64__
 611                 case SHT_X86_64_UNWIND:
 612 #endif
 613                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 614                                 break;
 615                         ef->nprogtab++;
 616                         break;
 617                 case SHT_SYMTAB:
 618                         nsym++;
 619                         symtabindex = i;
 620                         symstrindex = shdr[i].sh_link;
 621                         break;
 622                 case SHT_REL:
 623                         ef->nreltab++;
 624                         break;
 625                 case SHT_RELA:
 626                         ef->nrelatab++;
 627                         break;
 628                 case SHT_STRTAB:
 629                         break;
 630                 }
 631         }
 632         if (ef->nprogtab == 0) {
 633                 link_elf_error(filename, "file has no contents");
 634                 error = ENOEXEC;
 635                 goto out;
 636         }
 637         if (nsym != 1) {
 638                 /* Only allow one symbol table for now */
 639                 link_elf_error(filename, "file has no valid symbol table");
 640                 error = ENOEXEC;
 641                 goto out;
 642         }
 643         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 644             shdr[symstrindex].sh_type != SHT_STRTAB) {
 645                 link_elf_error(filename, "file has invalid symbol strings");
 646                 error = ENOEXEC;
 647                 goto out;
 648         }
 649
 650         /* Allocate space for tracking the load chunks */
 651         if (ef->nprogtab != 0)
 652                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 653                     M_LINKER, M_WAITOK | M_ZERO);
 654         if (ef->nreltab != 0)
 655                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 656                     M_LINKER, M_WAITOK | M_ZERO);
 657         if (ef->nrelatab != 0)
 658                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 659                     M_LINKER, M_WAITOK | M_ZERO);
 660
 661         if (symtabindex == -1) {
 662                 link_elf_error(filename, "lost symbol table index");
 663                 error = ENOEXEC;
 664                 goto out;
 665         }
 666         /* Allocate space for and load the symbol table */
 667         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 668         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 669         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 670             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 671             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 672             &resid, td);
 673         if (error)
 674                 goto out;
 675         if (resid != 0){
 676                 error = EINVAL;
 677                 goto out;
 678         }
 679
 680         if (symstrindex == -1) {
 681                 link_elf_error(filename, "lost symbol string index");
 682                 error = ENOEXEC;
 683                 goto out;
 684         }
 685         /* Allocate space for and load the symbol strings */
 686         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 687         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 688         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 689             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 690             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 691             &resid, td);
 692         if (error)
 693                 goto out;
 694         if (resid != 0){
 695                 error = EINVAL;
 696                 goto out;
 697         }
 698
 699         /* Do we have a string table for the section names?  */
 700         shstrindex = -1;
 701         if (hdr->e_shstrndx != 0 &&
 702             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 703                 shstrindex = hdr->e_shstrndx;
 704                 ef->shstrcnt = shdr[shstrindex].sh_size;
 705                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 706                     M_WAITOK);
 707                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 708                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 709                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 710                     &resid, td);
 711                 if (error)
 712                         goto out;
 713                 if (resid != 0){
 714                         error = EINVAL;
 715                         goto out;
 716                 }
 717         }
 718
 719         /* Size up code/data(progbits) and bss(nobits). */
 720         alignmask = 0;
 721         for (i = 0; i < hdr->e_shnum; i++) {
 722                 if (shdr[i].sh_size == 0)
 723                         continue;
 724                 switch (shdr[i].sh_type) {
 725                 case SHT_PROGBITS:
 726                 case SHT_NOBITS:
 727 #ifdef __amd64__
 728                 case SHT_X86_64_UNWIND:
 729 #endif
 730                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 731                                 break;
 732                         alignmask = shdr[i].sh_addralign - 1;
 733                         mapsize += alignmask;
 734                         mapsize &= ~alignmask;
 735                         mapsize += shdr[i].sh_size;
 736                         break;
 737                 }
 738         }
 739
 740         /*
 741          * We know how much space we need for the text/data/bss/etc.
 742          * This stuff needs to be in a single chunk so that profiling etc
 743          * can get the bounds and gdb can associate offsets with modules
 744          */
 745         ef->object = vm_object_allocate(OBJT_DEFAULT,
 746             round_page(mapsize) >> PAGE_SHIFT);
 747         if (ef->object == NULL) {
 748                 error = ENOMEM;
 749                 goto out;
 750         }
 751         ef->address = (caddr_t) vm_map_min(kernel_map);
 752
 753         /*
 754          * In order to satisfy amd64's architectural requirements on the
 755          * location of code and data in the kernel's address space, request a
 756          * mapping that is above the kernel.
 757          */
 758 #ifdef __amd64__
 759         mapbase = KERNBASE;
 760 #else
 761         mapbase = VM_MIN_KERNEL_ADDRESS;
 762 #endif
 763         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 764             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 765             VM_PROT_ALL, 0);
 766         if (error) {
 767                 vm_object_deallocate(ef->object);
 768                 ef->object = 0;
 769                 goto out;
 770         }
 771
 772         /* Wire the pages */
 773         error = vm_map_wire(kernel_map, mapbase,
 774             mapbase + round_page(mapsize),
 775             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 776         if (error != KERN_SUCCESS) {
 777                 error = ENOMEM;
 778                 goto out;
 779         }
 780
 781         /* Inform the kld system about the situation */
 782         lf->address = ef->address = (caddr_t)mapbase;
 783         lf->size = mapsize;
 784
 785         /*
 786          * Now load code/data(progbits), zero bss(nobits), allocate space for
 787          * and load relocs
 788          */
 789         pb = 0;
 790         rl = 0;
 791         ra = 0;
 792         alignmask = 0;
 793         for (i = 0; i < hdr->e_shnum; i++) {
 794                 if (shdr[i].sh_size == 0)
 795                         continue;
 796                 switch (shdr[i].sh_type) {
 797                 case SHT_PROGBITS:
 798                 case SHT_NOBITS:
 799 #ifdef __amd64__
 800                 case SHT_X86_64_UNWIND:
 801 #endif
 802                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 803                                 break;
 804                         alignmask = shdr[i].sh_addralign - 1;
 805                         mapbase += alignmask;
 806                         mapbase &= ~alignmask;
 807                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 808                                 ef->progtab[pb].name =
 809                                     ef->shstrtab + shdr[i].sh_name;
 810                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 811                                         lf->ctors_addr = (caddr_t)mapbase;
 812                                         lf->ctors_size = shdr[i].sh_size;
 813                                 }
 814                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 815                                 ef->progtab[pb].name = "<<PROGBITS>>";
 816 #ifdef __amd64__
 817                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 818                                 ef->progtab[pb].name = "<<UNWIND>>";
 819 #endif
 820                         else
 821                                 ef->progtab[pb].name = "<<NOBITS>>";
 822                         if (ef->progtab[pb].name != NULL &&
 823                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 824                                 ef->progtab[pb].addr =
 825                                     dpcpu_alloc(shdr[i].sh_size);
 826 #ifdef VIMAGE
 827                         else if (ef->progtab[pb].name != NULL &&
 828                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 829                                 ef->progtab[pb].addr =
 830                                     vnet_data_alloc(shdr[i].sh_size);
 831 #endif
 832                         else
 833                                 ef->progtab[pb].addr =
 834                                     (void *)(uintptr_t)mapbase;
 835                         if (ef->progtab[pb].addr == NULL) {
 836                                 error = ENOSPC;
 837                                 goto out;
 838                         }
 839                         ef->progtab[pb].size = shdr[i].sh_size;
 840                         ef->progtab[pb].sec = i;
 841                         if (shdr[i].sh_type == SHT_PROGBITS
 842 #ifdef __amd64__
 843                             || shdr[i].sh_type == SHT_X86_64_UNWIND
 844 #endif
 845                             ) {
 846                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
 847                                     ef->progtab[pb].addr,
 848                                     shdr[i].sh_size, shdr[i].sh_offset,
 849                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 850                                     NOCRED, &resid, td);
 851                                 if (error)
 852                                         goto out;
 853                                 if (resid != 0){
 854                                         error = EINVAL;
 855                                         goto out;
 856                                 }
 857                                 /* Initialize the per-cpu or vnet area. */
 858                                 if (ef->progtab[pb].addr != (void *)mapbase &&
 859                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 860                                         dpcpu_copy(ef->progtab[pb].addr,
 861                                             shdr[i].sh_size);
 862 #ifdef VIMAGE
 863                                 else if (ef->progtab[pb].addr !=
 864                                     (void *)mapbase &&
 865                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 866                                         vnet_data_copy(ef->progtab[pb].addr,
 867                                             shdr[i].sh_size);
 868 #endif
 869                         } else
 870                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 871
 872                         /* Update all symbol values with the offset. */
 873                         for (j = 0; j < ef->ddbsymcnt; j++) {
 874                                 es = &ef->ddbsymtab[j];
 875                                 if (es->st_shndx != i)
 876                                         continue;
 877                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 878                         }
 879                         mapbase += shdr[i].sh_size;
 880                         pb++;
 881                         break;
 882                 case SHT_REL:
 883                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 884                             M_WAITOK);
 885                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 886                         ef->reltab[rl].sec = shdr[i].sh_info;
 887                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 888                             (void *)ef->reltab[rl].rel,
 889                             shdr[i].sh_size, shdr[i].sh_offset,
 890                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 891                             &resid, td);
 892                         if (error)
 893                                 goto out;
 894                         if (resid != 0){
 895                                 error = EINVAL;
 896                                 goto out;
 897                         }
 898                         rl++;
 899                         break;
 900                 case SHT_RELA:
 901                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 902                             M_WAITOK);
 903                         ef->relatab[ra].nrela =
 904                             shdr[i].sh_size / sizeof(Elf_Rela);
 905                         ef->relatab[ra].sec = shdr[i].sh_info;
 906                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 907                             (void *)ef->relatab[ra].rela,
 908                             shdr[i].sh_size, shdr[i].sh_offset,
 909                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 910                             &resid, td);
 911                         if (error)
 912                                 goto out;
 913                         if (resid != 0){
 914                                 error = EINVAL;
 915                                 goto out;
 916                         }
 917                         ra++;
 918                         break;
 919                 }
 920         }
 921         if (pb != ef->nprogtab) {
 922                 link_elf_error(filename, "lost progbits");
 923                 error = ENOEXEC;
 924                 goto out;
 925         }
 926         if (rl != ef->nreltab) {
 927                 link_elf_error(filename, "lost reltab");
 928                 error = ENOEXEC;
 929                 goto out;
 930         }
 931         if (ra != ef->nrelatab) {
 932                 link_elf_error(filename, "lost relatab");
 933                 error = ENOEXEC;
 934                 goto out;
 935         }
 936         if (mapbase != (vm_offset_t)ef->address + mapsize) {
 937                 printf(
 938                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 939                     filename != NULL ? filename : "<none>",
 940                     (u_long)mapbase, ef->address, (u_long)mapsize,
 941                     (u_long)(vm_offset_t)ef->address + mapsize);
 942                 error = ENOMEM;
 943                 goto out;
 944         }
 945
 946         /* Local intra-module relocations */
 947         error = link_elf_reloc_local(lf);
 948         if (error != 0)
 949                 goto out;
 950
 951         /* Pull in dependencies */
 952         VOP_UNLOCK(nd->ni_vp, 0);
 953         error = linker_load_dependencies(lf);
 954         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
 955         if (error)
 956                 goto out;
 957
 958         /* External relocations */
 959         error = relocate_file(ef);
 960         if (error)
 961                 goto out;
 962
 963         /* Notify MD code that a module is being loaded. */
 964         error = elf_cpu_load_file(lf);
 965         if (error)
 966                 goto out;
 967
 968         /* Invoke .ctors */
 969         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 970
 971         *result = lf;
 972
 973 out:
 974         VOP_UNLOCK(nd->ni_vp, 0);
 975         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
 976         free(nd, M_TEMP);
 977         if (error && lf)
 978                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 979         free(hdr, M_LINKER);
 980
 981         return error;
 982 }
 983
 984 static void
 985 link_elf_unload_file(linker_file_t file)
 986 {
 987         elf_file_t ef = (elf_file_t) file;
 988         int i;
 989
 990         /* Notify MD code that a module is being unloaded. */
 991         elf_cpu_unload_file(file);
 992
 993         if (ef->progtab) {
 994                 for (i = 0; i < ef->nprogtab; i++) {
 995                         if (ef->progtab[i].size == 0)
 996                                 continue;
 997                         if (ef->progtab[i].name == NULL)
 998                                 continue;
 999                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1000                                 dpcpu_free(ef->progtab[i].addr,
1001                                     ef->progtab[i].size);
1002 #ifdef VIMAGE
1003                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1004                                 vnet_data_free(ef->progtab[i].addr,
1005                                     ef->progtab[i].size);
1006 #endif
1007                 }
1008         }
1009         if (ef->preloaded) {
1010                 free(ef->reltab, M_LINKER);
1011                 free(ef->relatab, M_LINKER);
1012                 free(ef->progtab, M_LINKER);
1013                 free(ef->ctftab, M_LINKER);
1014                 free(ef->ctfoff, M_LINKER);
1015                 free(ef->typoff, M_LINKER);
1016                 if (file->filename != NULL)
1017                         preload_delete_name(file->filename);
1018                 /* XXX reclaim module memory? */
1019                 return;
1020         }
1021
1022         for (i = 0; i < ef->nreltab; i++)
1023                 free(ef->reltab[i].rel, M_LINKER);
1024         for (i = 0; i < ef->nrelatab; i++)
1025                 free(ef->relatab[i].rela, M_LINKER);
1026         free(ef->reltab, M_LINKER);
1027         free(ef->relatab, M_LINKER);
1028         free(ef->progtab, M_LINKER);
1029
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         free(ef->e_shdr, M_LINKER);
1036         free(ef->ddbsymtab, M_LINKER);
1037         free(ef->ddbstrtab, M_LINKER);
1038         free(ef->shstrtab, M_LINKER);
1039         free(ef->ctftab, M_LINKER);
1040         free(ef->ctfoff, M_LINKER);
1041         free(ef->typoff, M_LINKER);
1042 }
1043
1044 static const char *
1045 symbol_name(elf_file_t ef, Elf_Size r_info)
1046 {
1047         const Elf_Sym *ref;
1048
1049         if (ELF_R_SYM(r_info)) {
1050                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1051                 return ef->ddbstrtab + ref->st_name;
1052         } else
1053                 return NULL;
1054 }
1055
1056 static Elf_Addr
1057 findbase(elf_file_t ef, int sec)
1058 {
1059         int i;
1060         Elf_Addr base = 0;
1061
1062         for (i = 0; i < ef->nprogtab; i++) {
1063                 if (sec == ef->progtab[i].sec) {
1064                         base = (Elf_Addr)ef->progtab[i].addr;
1065                         break;
1066                 }
1067         }
1068         return base;
1069 }
1070
1071 static int
1072 relocate_file(elf_file_t ef)
1073 {
1074         const Elf_Rel *rellim;
1075         const Elf_Rel *rel;
1076         const Elf_Rela *relalim;
1077         const Elf_Rela *rela;
1078         const char *symname;
1079         const Elf_Sym *sym;
1080         int i;
1081         Elf_Size symidx;
1082         Elf_Addr base;
1083
1084
1085         /* Perform relocations without addend if there are any: */
1086         for (i = 0; i < ef->nreltab; i++) {
1087                 rel = ef->reltab[i].rel;
1088                 if (rel == NULL) {
1089                         link_elf_error(ef->lf.filename, "lost a reltab!");
1090                         return (ENOEXEC);
1091                 }
1092                 rellim = rel + ef->reltab[i].nrel;
1093                 base = findbase(ef, ef->reltab[i].sec);
1094                 if (base == 0) {
1095                         link_elf_error(ef->lf.filename, "lost base for reltab");
1096                         return (ENOEXEC);
1097                 }
1098                 for ( ; rel < rellim; rel++) {
1099                         symidx = ELF_R_SYM(rel->r_info);
1100                         if (symidx >= ef->ddbsymcnt)
1101                                 continue;
1102                         sym = ef->ddbsymtab + symidx;
1103                         /* Local relocs are already done */
1104                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1105                                 continue;
1106                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1107                             elf_obj_lookup)) {
1108                                 symname = symbol_name(ef, rel->r_info);
1109                                 printf("link_elf_obj: symbol %s undefined\n",
1110                                     symname);
1111                                 return (ENOENT);
1112                         }
1113                 }
1114         }
1115
1116         /* Perform relocations with addend if there are any: */
1117         for (i = 0; i < ef->nrelatab; i++) {
1118                 rela = ef->relatab[i].rela;
1119                 if (rela == NULL) {
1120                         link_elf_error(ef->lf.filename, "lost a relatab!");
1121                         return (ENOEXEC);
1122                 }
1123                 relalim = rela + ef->relatab[i].nrela;
1124                 base = findbase(ef, ef->relatab[i].sec);
1125                 if (base == 0) {
1126                         link_elf_error(ef->lf.filename,
1127                             "lost base for relatab");
1128                         return (ENOEXEC);
1129                 }
1130                 for ( ; rela < relalim; rela++) {
1131                         symidx = ELF_R_SYM(rela->r_info);
1132                         if (symidx >= ef->ddbsymcnt)
1133                                 continue;
1134                         sym = ef->ddbsymtab + symidx;
1135                         /* Local relocs are already done */
1136                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1137                                 continue;
1138                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1139                             elf_obj_lookup)) {
1140                                 symname = symbol_name(ef, rela->r_info);
1141                                 printf("link_elf_obj: symbol %s undefined\n",
1142                                     symname);
1143                                 return (ENOENT);
1144                         }
1145                 }
1146         }
1147
1148         /*
1149          * Only clean SHN_FBSD_CACHED for successful return.  If we
1150          * modified symbol table for the object but found an
1151          * unresolved symbol, there is no reason to roll back.
1152          */
1153         elf_obj_cleanup_globals_cache(ef);
1154
1155         return (0);
1156 }
1157
1158 static int
1159 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1160 {
1161         elf_file_t ef = (elf_file_t) lf;
1162         const Elf_Sym *symp;
1163         const char *strp;
1164         int i;
1165
1166         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1167                 strp = ef->ddbstrtab + symp->st_name;
1168                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1169                         *sym = (c_linker_sym_t) symp;
1170                         return 0;
1171                 }
1172         }
1173         return ENOENT;
1174 }
1175
1176 static int
1177 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1178     linker_symval_t *symval)
1179 {
1180         elf_file_t ef = (elf_file_t) lf;
1181         const Elf_Sym *es = (const Elf_Sym*) sym;
1182
1183         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1184                 symval->name = ef->ddbstrtab + es->st_name;
1185                 symval->value = (caddr_t)es->st_value;
1186                 symval->size = es->st_size;
1187                 return 0;
1188         }
1189         return ENOENT;
1190 }
1191
1192 static int
1193 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1194     c_linker_sym_t *sym, long *diffp)
1195 {
1196         elf_file_t ef = (elf_file_t) lf;
1197         u_long off = (uintptr_t) (void *) value;
1198         u_long diff = off;
1199         u_long st_value;
1200         const Elf_Sym *es;
1201         const Elf_Sym *best = NULL;
1202         int i;
1203
1204         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1205                 if (es->st_name == 0)
1206                         continue;
1207                 st_value = es->st_value;
1208                 if (off >= st_value) {
1209                         if (off - st_value < diff) {
1210                                 diff = off - st_value;
1211                                 best = es;
1212                                 if (diff == 0)
1213                                         break;
1214                         } else if (off - st_value == diff) {
1215                                 best = es;
1216                         }
1217                 }
1218         }
1219         if (best == NULL)
1220                 *diffp = off;
1221         else
1222                 *diffp = diff;
1223         *sym = (c_linker_sym_t) best;
1224
1225         return 0;
1226 }
1227
1228 /*
1229  * Look up a linker set on an ELF system.
1230  */
1231 static int
1232 link_elf_lookup_set(linker_file_t lf, const char *name,
1233     void ***startp, void ***stopp, int *countp)
1234 {
1235         elf_file_t ef = (elf_file_t)lf;
1236         void **start, **stop;
1237         int i, count;
1238
1239         /* Relative to section number */
1240         for (i = 0; i < ef->nprogtab; i++) {
1241                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1242                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1243                         start  = (void **)ef->progtab[i].addr;
1244                         stop = (void **)((char *)ef->progtab[i].addr +
1245                             ef->progtab[i].size);
1246                         count = stop - start;
1247                         if (startp)
1248                                 *startp = start;
1249                         if (stopp)
1250                                 *stopp = stop;
1251                         if (countp)
1252                                 *countp = count;
1253                         return (0);
1254                 }
1255         }
1256         return (ESRCH);
1257 }
1258
1259 static int
1260 link_elf_each_function_name(linker_file_t file,
1261     int (*callback)(const char *, void *), void *opaque)
1262 {
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 = callback(ef->ddbstrtab + symp->st_name, opaque);
1272                         if (error)
1273                                 return (error);
1274                 }
1275         }
1276         return (0);
1277 }
1278
1279 static int
1280 link_elf_each_function_nameval(linker_file_t file,
1281     linker_function_nameval_callback_t callback, void *opaque)
1282 {
1283         linker_symval_t symval;
1284         elf_file_t ef = (elf_file_t)file;
1285         const Elf_Sym* symp;
1286         int i, error;
1287
1288         /* Exhaustive search */
1289         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1290                 if (symp->st_value != 0 &&
1291                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1292                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1293                         if (error)
1294                                 return (error);
1295                         error = callback(file, i, &symval, opaque);
1296                         if (error)
1297                                 return (error);
1298                 }
1299         }
1300         return (0);
1301 }
1302
1303 static void
1304 elf_obj_cleanup_globals_cache(elf_file_t ef)
1305 {
1306         Elf_Sym *sym;
1307         Elf_Size i;
1308
1309         for (i = 0; i < ef->ddbsymcnt; i++) {
1310                 sym = ef->ddbsymtab + i;
1311                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1312                         sym->st_shndx = SHN_UNDEF;
1313                         sym->st_value = 0;
1314                 }
1315         }
1316 }
1317
1318 /*
1319  * Symbol lookup function that can be used when the symbol index is known (ie
1320  * in relocations). It uses the symbol index instead of doing a fully fledged
1321  * hash table based lookup when such is valid. For example for local symbols.
1322  * This is not only more efficient, it's also more correct. It's not always
1323  * the case that the symbol can be found through the hash table.
1324  */
1325 static int
1326 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1327 {
1328         elf_file_t ef = (elf_file_t)lf;
1329         Elf_Sym *sym;
1330         const char *symbol;
1331         Elf_Addr res1;
1332
1333         /* Don't even try to lookup the symbol if the index is bogus. */
1334         if (symidx >= ef->ddbsymcnt) {
1335                 *res = 0;
1336                 return (EINVAL);
1337         }
1338
1339         sym = ef->ddbsymtab + symidx;
1340
1341         /* Quick answer if there is a definition included. */
1342         if (sym->st_shndx != SHN_UNDEF) {
1343                 *res = sym->st_value;
1344                 return (0);
1345         }
1346
1347         /* If we get here, then it is undefined and needs a lookup. */
1348         switch (ELF_ST_BIND(sym->st_info)) {
1349         case STB_LOCAL:
1350                 /* Local, but undefined? huh? */
1351                 *res = 0;
1352                 return (EINVAL);
1353
1354         case STB_GLOBAL:
1355         case STB_WEAK:
1356                 /* Relative to Data or Function name */
1357                 symbol = ef->ddbstrtab + sym->st_name;
1358
1359                 /* Force a lookup failure if the symbol name is bogus. */
1360                 if (*symbol == 0) {
1361                         *res = 0;
1362                         return (EINVAL);
1363                 }
1364                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1365
1366                 /*
1367                  * Cache global lookups during module relocation. The failure
1368                  * case is particularly expensive for callers, who must scan
1369                  * through the entire globals table doing strcmp(). Cache to
1370                  * avoid doing such work repeatedly.
1371                  *
1372                  * After relocation is complete, undefined globals will be
1373                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1374                  * above.
1375                  */
1376                 if (res1 != 0) {
1377                         sym->st_shndx = SHN_FBSD_CACHED;
1378                         sym->st_value = res1;
1379                         *res = res1;
1380                         return (0);
1381                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1382                         sym->st_value = 0;
1383                         *res = 0;
1384                         return (0);
1385                 }
1386                 return (EINVAL);
1387
1388         default:
1389                 return (EINVAL);
1390         }
1391 }
1392
1393 static void
1394 link_elf_fix_link_set(elf_file_t ef)
1395 {
1396         static const char startn[] = "__start_";
1397         static const char stopn[] = "__stop_";
1398         Elf_Sym *sym;
1399         const char *sym_name, *linkset_name;
1400         Elf_Addr startp, stopp;
1401         Elf_Size symidx;
1402         int start, i;
1403
1404         startp = stopp = 0;
1405         for (symidx = 1 /* zero entry is special */;
1406                 symidx < ef->ddbsymcnt; symidx++) {
1407                 sym = ef->ddbsymtab + symidx;
1408                 if (sym->st_shndx != SHN_UNDEF)
1409                         continue;
1410
1411                 sym_name = ef->ddbstrtab + sym->st_name;
1412                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1413                         start = 1;
1414                         linkset_name = sym_name + sizeof(startn) - 1;
1415                 }
1416                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1417                         start = 0;
1418                         linkset_name = sym_name + sizeof(stopn) - 1;
1419                 }
1420                 else
1421                         continue;
1422
1423                 for (i = 0; i < ef->nprogtab; i++) {
1424                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1425                                 startp = (Elf_Addr)ef->progtab[i].addr;
1426                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1427                                 break;
1428                         }
1429                 }
1430                 if (i == ef->nprogtab)
1431                         continue;
1432
1433                 sym->st_value = start ? startp : stopp;
1434                 sym->st_shndx = i;
1435         }
1436 }
1437
1438 static int
1439 link_elf_reloc_local(linker_file_t lf)
1440 {
1441         elf_file_t ef = (elf_file_t)lf;
1442         const Elf_Rel *rellim;
1443         const Elf_Rel *rel;
1444         const Elf_Rela *relalim;
1445         const Elf_Rela *rela;
1446         const Elf_Sym *sym;
1447         Elf_Addr base;
1448         int i;
1449         Elf_Size symidx;
1450
1451         link_elf_fix_link_set(ef);
1452
1453         /* Perform relocations without addend if there are any: */
1454         for (i = 0; i < ef->nreltab; i++) {
1455                 rel = ef->reltab[i].rel;
1456                 if (rel == NULL) {
1457                         link_elf_error(ef->lf.filename, "lost a reltab");
1458                         return (ENOEXEC);
1459                 }
1460                 rellim = rel + ef->reltab[i].nrel;
1461                 base = findbase(ef, ef->reltab[i].sec);
1462                 if (base == 0) {
1463                         link_elf_error(ef->lf.filename, "lost base for reltab");
1464                         return (ENOEXEC);
1465                 }
1466                 for ( ; rel < rellim; rel++) {
1467                         symidx = ELF_R_SYM(rel->r_info);
1468                         if (symidx >= ef->ddbsymcnt)
1469                                 continue;
1470                         sym = ef->ddbsymtab + symidx;
1471                         /* Only do local relocs */
1472                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1473                                 continue;
1474                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1475                             elf_obj_lookup);
1476                 }
1477         }
1478
1479         /* Perform relocations with addend if there are any: */
1480         for (i = 0; i < ef->nrelatab; i++) {
1481                 rela = ef->relatab[i].rela;
1482                 if (rela == NULL) {
1483                         link_elf_error(ef->lf.filename, "lost a relatab!");
1484                         return (ENOEXEC);
1485                 }
1486                 relalim = rela + ef->relatab[i].nrela;
1487                 base = findbase(ef, ef->relatab[i].sec);
1488                 if (base == 0) {
1489                         link_elf_error(ef->lf.filename, "lost base for reltab");
1490                         return (ENOEXEC);
1491                 }
1492                 for ( ; rela < relalim; rela++) {
1493                         symidx = ELF_R_SYM(rela->r_info);
1494                         if (symidx >= ef->ddbsymcnt)
1495                                 continue;
1496                         sym = ef->ddbsymtab + symidx;
1497                         /* Only do local relocs */
1498                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1499                                 continue;
1500                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1501                             elf_obj_lookup);
1502                 }
1503         }
1504         return (0);
1505 }
1506
1507 static long
1508 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1509 {
1510     elf_file_t ef = (elf_file_t)lf;
1511
1512     *symtab = ef->ddbsymtab;
1513
1514     if (*symtab == NULL)
1515         return (0);
1516
1517     return (ef->ddbsymcnt);
1518 }
1519
1520 static long
1521 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1522 {
1523     elf_file_t ef = (elf_file_t)lf;
1524
1525     *strtab = ef->ddbstrtab;
1526
1527     if (*strtab == NULL)
1528         return (0);
1529
1530     return (ef->ddbstrcnt);
1531 }