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                         ef->nprogtab++;
 266                         break;
 267                 case SHT_SYMTAB:
 268                         symtabindex = i;
 269                         symstrindex = shdr[i].sh_link;
 270                         break;
 271                 case SHT_REL:
 272                         ef->nreltab++;
 273                         break;
 274                 case SHT_RELA:
 275                         ef->nrelatab++;
 276                         break;
 277                 }
 278         }
 279
 280         shstrindex = hdr->e_shstrndx;
 281         if (ef->nprogtab == 0 || symstrindex < 0 ||
 282             symstrindex >= hdr->e_shnum ||
 283             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 284             shstrindex >= hdr->e_shnum ||
 285             shdr[shstrindex].sh_type != SHT_STRTAB) {
 286                 printf("%s: bad/missing section headers\n", filename);
 287                 error = ENOEXEC;
 288                 goto out;
 289         }
 290
 291         /* Allocate space for tracking the load chunks */
 292         if (ef->nprogtab != 0)
 293                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 294                     M_LINKER, M_WAITOK | M_ZERO);
 295         if (ef->nreltab != 0)
 296                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 297                     M_LINKER, M_WAITOK | M_ZERO);
 298         if (ef->nrelatab != 0)
 299                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 300                     M_LINKER, M_WAITOK | M_ZERO);
 301         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 302             (ef->nreltab != 0 && ef->reltab == NULL) ||
 303             (ef->nrelatab != 0 && ef->relatab == NULL)) {
 304                 error = ENOMEM;
 305                 goto out;
 306         }
 307
 308         /* XXX, relocate the sh_addr fields saved by the loader. */
 309         off = 0;
 310         for (i = 0; i < hdr->e_shnum; i++) {
 311                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 312                         off = shdr[i].sh_addr;
 313         }
 314         for (i = 0; i < hdr->e_shnum; i++) {
 315                 if (shdr[i].sh_addr != 0)
 316                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 317                             (Elf_Addr)ef->address;
 318         }
 319
 320         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 321         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 322         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 323         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 324         ef->shstrcnt = shdr[shstrindex].sh_size;
 325         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 326
 327         /* Now fill out progtab and the relocation tables. */
 328         pb = 0;
 329         rl = 0;
 330         ra = 0;
 331         for (i = 0; i < hdr->e_shnum; i++) {
 332                 switch (shdr[i].sh_type) {
 333                 case SHT_PROGBITS:
 334                 case SHT_NOBITS:
 335 #ifdef __amd64__
 336                 case SHT_X86_64_UNWIND:
 337 #endif
 338                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 339                         if (shdr[i].sh_type == SHT_PROGBITS)
 340                                 ef->progtab[pb].name = "<<PROGBITS>>";
 341 #ifdef __amd64__
 342                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 343                                 ef->progtab[pb].name = "<<UNWIND>>";
 344 #endif
 345                         else
 346                                 ef->progtab[pb].name = "<<NOBITS>>";
 347                         ef->progtab[pb].size = shdr[i].sh_size;
 348                         ef->progtab[pb].sec = i;
 349                         if (ef->shstrtab && shdr[i].sh_name != 0)
 350                                 ef->progtab[pb].name =
 351                                     ef->shstrtab + shdr[i].sh_name;
 352                         if (ef->progtab[pb].name != NULL &&
 353                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 354                                 void *dpcpu;
 355
 356                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
 357                                 if (dpcpu == NULL) {
 358                                         error = ENOSPC;
 359                                         goto out;
 360                                 }
 361                                 memcpy(dpcpu, ef->progtab[pb].addr,
 362                                     ef->progtab[pb].size);
 363                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
 364                                 ef->progtab[pb].addr = dpcpu;
 365 #ifdef VIMAGE
 366                         } else if (ef->progtab[pb].name != NULL &&
 367                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 368                                 void *vnet_data;
 369
 370                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
 371                                 if (vnet_data == NULL) {
 372                                         error = ENOSPC;
 373                                         goto out;
 374                                 }
 375                                 memcpy(vnet_data, ef->progtab[pb].addr,
 376                                     ef->progtab[pb].size);
 377                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
 378                                 ef->progtab[pb].addr = vnet_data;
 379 #endif
 380                         } else if (ef->progtab[pb].name != NULL &&
 381                             !strcmp(ef->progtab[pb].name, ".ctors")) {
 382                                 lf->ctors_addr = ef->progtab[pb].addr;
 383                                 lf->ctors_size = shdr[i].sh_size;
 384                         }
 385
 386                         /* Update all symbol values with the offset. */
 387                         for (j = 0; j < ef->ddbsymcnt; j++) {
 388                                 es = &ef->ddbsymtab[j];
 389                                 if (es->st_shndx != i)
 390                                         continue;
 391                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 392                         }
 393                         pb++;
 394                         break;
 395                 case SHT_REL:
 396                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 397                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 398                         ef->reltab[rl].sec = shdr[i].sh_info;
 399                         rl++;
 400                         break;
 401                 case SHT_RELA:
 402                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 403                         ef->relatab[ra].nrela =
 404                             shdr[i].sh_size / sizeof(Elf_Rela);
 405                         ef->relatab[ra].sec = shdr[i].sh_info;
 406                         ra++;
 407                         break;
 408                 }
 409         }
 410         if (pb != ef->nprogtab) {
 411                 printf("%s: lost progbits\n", filename);
 412                 error = ENOEXEC;
 413                 goto out;
 414         }
 415         if (rl != ef->nreltab) {
 416                 printf("%s: lost reltab\n", filename);
 417                 error = ENOEXEC;
 418                 goto out;
 419         }
 420         if (ra != ef->nrelatab) {
 421                 printf("%s: lost relatab\n", filename);
 422                 error = ENOEXEC;
 423                 goto out;
 424         }
 425
 426         /* Local intra-module relocations */
 427         error = link_elf_reloc_local(lf);
 428         if (error != 0)
 429                 goto out;
 430
 431         *result = lf;
 432         return (0);
 433
 434 out:
 435         /* preload not done this way */
 436         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 437         return (error);
 438 }
 439
 440 static void
 441 link_elf_invoke_ctors(caddr_t addr, size_t size)
 442 {
 443         void (**ctor)(void);
 444         size_t i, cnt;
 445
 446         if (addr == NULL || size == 0)
 447                 return;
 448         cnt = size / sizeof(*ctor);
 449         ctor = (void *)addr;
 450         for (i = 0; i < cnt; i++) {
 451                 if (ctor[i] != NULL)
 452                         (*ctor[i])();
 453         }
 454 }
 455
 456 static int
 457 link_elf_link_preload_finish(linker_file_t lf)
 458 {
 459         elf_file_t ef;
 460         int error;
 461
 462         ef = (elf_file_t)lf;
 463         error = relocate_file(ef);
 464         if (error)
 465                 return error;
 466
 467         /* Notify MD code that a module is being loaded. */
 468         error = elf_cpu_load_file(lf);
 469         if (error)
 470                 return (error);
 471
 472         /* Invoke .ctors */
 473         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 474         return (0);
 475 }
 476
 477 static int
 478 link_elf_load_file(linker_class_t cls, const char *filename,
 479     linker_file_t *result)
 480 {
 481         struct nameidata *nd;
 482         struct thread *td = curthread;  /* XXX */
 483         Elf_Ehdr *hdr;
 484         Elf_Shdr *shdr;
 485         Elf_Sym *es;
 486         int nbytes, i, j;
 487         vm_offset_t mapbase;
 488         size_t mapsize;
 489         int error = 0;
 490         ssize_t resid;
 491         int flags;
 492         elf_file_t ef;
 493         linker_file_t lf;
 494         int symtabindex;
 495         int symstrindex;
 496         int shstrindex;
 497         int nsym;
 498         int pb, rl, ra;
 499         int alignmask;
 500
 501         shdr = NULL;
 502         lf = NULL;
 503         mapsize = 0;
 504         hdr = NULL;
 505
 506         nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
 507         NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 508         flags = FREAD;
 509         error = vn_open(nd, &flags, 0, NULL);
 510         if (error) {
 511                 free(nd, M_TEMP);
 512                 return error;
 513         }
 514         NDFREE(nd, NDF_ONLY_PNBUF);
 515         if (nd->ni_vp->v_type != VREG) {
 516                 error = ENOEXEC;
 517                 goto out;
 518         }
 519 #ifdef MAC
 520         error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
 521         if (error) {
 522                 goto out;
 523         }
 524 #endif
 525
 526         /* Read the elf header from the file. */
 527         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 528         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
 529             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 530             &resid, td);
 531         if (error)
 532                 goto out;
 533         if (resid != 0){
 534                 error = ENOEXEC;
 535                 goto out;
 536         }
 537
 538         if (!IS_ELF(*hdr)) {
 539                 error = ENOEXEC;
 540                 goto out;
 541         }
 542
 543         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 544             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 545                 link_elf_error(filename, "Unsupported file layout");
 546                 error = ENOEXEC;
 547                 goto out;
 548         }
 549         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 550             || hdr->e_version != EV_CURRENT) {
 551                 link_elf_error(filename, "Unsupported file version");
 552                 error = ENOEXEC;
 553                 goto out;
 554         }
 555         if (hdr->e_type != ET_REL) {
 556                 error = ENOSYS;
 557                 goto out;
 558         }
 559         if (hdr->e_machine != ELF_TARG_MACH) {
 560                 link_elf_error(filename, "Unsupported machine");
 561                 error = ENOEXEC;
 562                 goto out;
 563         }
 564
 565         lf = linker_make_file(filename, &link_elf_class);
 566         if (!lf) {
 567                 error = ENOMEM;
 568                 goto out;
 569         }
 570         ef = (elf_file_t) lf;
 571         ef->nprogtab = 0;
 572         ef->e_shdr = 0;
 573         ef->nreltab = 0;
 574         ef->nrelatab = 0;
 575
 576         /* Allocate and read in the section header */
 577         nbytes = hdr->e_shnum * hdr->e_shentsize;
 578         if (nbytes == 0 || hdr->e_shoff == 0 ||
 579             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 580                 error = ENOEXEC;
 581                 goto out;
 582         }
 583         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 584         ef->e_shdr = shdr;
 585         error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
 586             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 587             NOCRED, &resid, td);
 588         if (error)
 589                 goto out;
 590         if (resid) {
 591                 error = ENOEXEC;
 592                 goto out;
 593         }
 594
 595         /* Scan the section header for information and table sizing. */
 596         nsym = 0;
 597         symtabindex = -1;
 598         symstrindex = -1;
 599         for (i = 0; i < hdr->e_shnum; i++) {
 600                 if (shdr[i].sh_size == 0)
 601                         continue;
 602                 switch (shdr[i].sh_type) {
 603                 case SHT_PROGBITS:
 604                 case SHT_NOBITS:
 605 #ifdef __amd64__
 606                 case SHT_X86_64_UNWIND:
 607 #endif
 608                         ef->nprogtab++;
 609                         break;
 610                 case SHT_SYMTAB:
 611                         nsym++;
 612                         symtabindex = i;
 613                         symstrindex = shdr[i].sh_link;
 614                         break;
 615                 case SHT_REL:
 616                         ef->nreltab++;
 617                         break;
 618                 case SHT_RELA:
 619                         ef->nrelatab++;
 620                         break;
 621                 case SHT_STRTAB:
 622                         break;
 623                 }
 624         }
 625         if (ef->nprogtab == 0) {
 626                 link_elf_error(filename, "file has no contents");
 627                 error = ENOEXEC;
 628                 goto out;
 629         }
 630         if (nsym != 1) {
 631                 /* Only allow one symbol table for now */
 632                 link_elf_error(filename, "file has no valid symbol table");
 633                 error = ENOEXEC;
 634                 goto out;
 635         }
 636         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 637             shdr[symstrindex].sh_type != SHT_STRTAB) {
 638                 link_elf_error(filename, "file has invalid symbol strings");
 639                 error = ENOEXEC;
 640                 goto out;
 641         }
 642
 643         /* Allocate space for tracking the load chunks */
 644         if (ef->nprogtab != 0)
 645                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 646                     M_LINKER, M_WAITOK | M_ZERO);
 647         if (ef->nreltab != 0)
 648                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 649                     M_LINKER, M_WAITOK | M_ZERO);
 650         if (ef->nrelatab != 0)
 651                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 652                     M_LINKER, M_WAITOK | M_ZERO);
 653
 654         if (symtabindex == -1) {
 655                 link_elf_error(filename, "lost symbol table index");
 656                 error = ENOEXEC;
 657                 goto out;
 658         }
 659         /* Allocate space for and load the symbol table */
 660         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 661         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 662         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 663             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 664             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 665             &resid, td);
 666         if (error)
 667                 goto out;
 668         if (resid != 0){
 669                 error = EINVAL;
 670                 goto out;
 671         }
 672
 673         if (symstrindex == -1) {
 674                 link_elf_error(filename, "lost symbol string index");
 675                 error = ENOEXEC;
 676                 goto out;
 677         }
 678         /* Allocate space for and load the symbol strings */
 679         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 680         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 681         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 682             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 683             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 684             &resid, td);
 685         if (error)
 686                 goto out;
 687         if (resid != 0){
 688                 error = EINVAL;
 689                 goto out;
 690         }
 691
 692         /* Do we have a string table for the section names?  */
 693         shstrindex = -1;
 694         if (hdr->e_shstrndx != 0 &&
 695             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 696                 shstrindex = hdr->e_shstrndx;
 697                 ef->shstrcnt = shdr[shstrindex].sh_size;
 698                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 699                     M_WAITOK);
 700                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 701                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 702                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 703                     &resid, td);
 704                 if (error)
 705                         goto out;
 706                 if (resid != 0){
 707                         error = EINVAL;
 708                         goto out;
 709                 }
 710         }
 711
 712         /* Size up code/data(progbits) and bss(nobits). */
 713         alignmask = 0;
 714         for (i = 0; i < hdr->e_shnum; i++) {
 715                 if (shdr[i].sh_size == 0)
 716                         continue;
 717                 switch (shdr[i].sh_type) {
 718                 case SHT_PROGBITS:
 719                 case SHT_NOBITS:
 720 #ifdef __amd64__
 721                 case SHT_X86_64_UNWIND:
 722 #endif
 723                         alignmask = shdr[i].sh_addralign - 1;
 724                         mapsize += alignmask;
 725                         mapsize &= ~alignmask;
 726                         mapsize += shdr[i].sh_size;
 727                         break;
 728                 }
 729         }
 730
 731         /*
 732          * We know how much space we need for the text/data/bss/etc.
 733          * This stuff needs to be in a single chunk so that profiling etc
 734          * can get the bounds and gdb can associate offsets with modules
 735          */
 736         ef->object = vm_object_allocate(OBJT_DEFAULT,
 737             round_page(mapsize) >> PAGE_SHIFT);
 738         if (ef->object == NULL) {
 739                 error = ENOMEM;
 740                 goto out;
 741         }
 742         ef->address = (caddr_t) vm_map_min(kernel_map);
 743
 744         /*
 745          * In order to satisfy amd64's architectural requirements on the
 746          * location of code and data in the kernel's address space, request a
 747          * mapping that is above the kernel.
 748          */
 749 #ifdef __amd64__
 750         mapbase = KERNBASE;
 751 #else
 752         mapbase = VM_MIN_KERNEL_ADDRESS;
 753 #endif
 754         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 755             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 756             VM_PROT_ALL, 0);
 757         if (error) {
 758                 vm_object_deallocate(ef->object);
 759                 ef->object = 0;
 760                 goto out;
 761         }
 762
 763         /* Wire the pages */
 764         error = vm_map_wire(kernel_map, mapbase,
 765             mapbase + round_page(mapsize),
 766             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 767         if (error != KERN_SUCCESS) {
 768                 error = ENOMEM;
 769                 goto out;
 770         }
 771
 772         /* Inform the kld system about the situation */
 773         lf->address = ef->address = (caddr_t)mapbase;
 774         lf->size = mapsize;
 775
 776         /*
 777          * Now load code/data(progbits), zero bss(nobits), allocate space for
 778          * and load relocs
 779          */
 780         pb = 0;
 781         rl = 0;
 782         ra = 0;
 783         alignmask = 0;
 784         for (i = 0; i < hdr->e_shnum; i++) {
 785                 if (shdr[i].sh_size == 0)
 786                         continue;
 787                 switch (shdr[i].sh_type) {
 788                 case SHT_PROGBITS:
 789                 case SHT_NOBITS:
 790 #ifdef __amd64__
 791                 case SHT_X86_64_UNWIND:
 792 #endif
 793                         alignmask = shdr[i].sh_addralign - 1;
 794                         mapbase += alignmask;
 795                         mapbase &= ~alignmask;
 796                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 797                                 ef->progtab[pb].name =
 798                                     ef->shstrtab + shdr[i].sh_name;
 799                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 800                                         lf->ctors_addr = (caddr_t)mapbase;
 801                                         lf->ctors_size = shdr[i].sh_size;
 802                                 }
 803                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 804                                 ef->progtab[pb].name = "<<PROGBITS>>";
 805 #ifdef __amd64__
 806                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 807                                 ef->progtab[pb].name = "<<UNWIND>>";
 808 #endif
 809                         else
 810                                 ef->progtab[pb].name = "<<NOBITS>>";
 811                         if (ef->progtab[pb].name != NULL &&
 812                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 813                                 ef->progtab[pb].addr =
 814                                     dpcpu_alloc(shdr[i].sh_size);
 815 #ifdef VIMAGE
 816                         else if (ef->progtab[pb].name != NULL &&
 817                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 818                                 ef->progtab[pb].addr =
 819                                     vnet_data_alloc(shdr[i].sh_size);
 820 #endif
 821                         else
 822                                 ef->progtab[pb].addr =
 823                                     (void *)(uintptr_t)mapbase;
 824                         if (ef->progtab[pb].addr == NULL) {
 825                                 error = ENOSPC;
 826                                 goto out;
 827                         }
 828                         ef->progtab[pb].size = shdr[i].sh_size;
 829                         ef->progtab[pb].sec = i;
 830                         if (shdr[i].sh_type == SHT_PROGBITS
 831 #ifdef __amd64__
 832                             || shdr[i].sh_type == SHT_X86_64_UNWIND
 833 #endif
 834                             ) {
 835                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
 836                                     ef->progtab[pb].addr,
 837                                     shdr[i].sh_size, shdr[i].sh_offset,
 838                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 839                                     NOCRED, &resid, td);
 840                                 if (error)
 841                                         goto out;
 842                                 if (resid != 0){
 843                                         error = EINVAL;
 844                                         goto out;
 845                                 }
 846                                 /* Initialize the per-cpu or vnet area. */
 847                                 if (ef->progtab[pb].addr != (void *)mapbase &&
 848                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 849                                         dpcpu_copy(ef->progtab[pb].addr,
 850                                             shdr[i].sh_size);
 851 #ifdef VIMAGE
 852                                 else if (ef->progtab[pb].addr !=
 853                                     (void *)mapbase &&
 854                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 855                                         vnet_data_copy(ef->progtab[pb].addr,
 856                                             shdr[i].sh_size);
 857 #endif
 858                         } else
 859                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 860
 861                         /* Update all symbol values with the offset. */
 862                         for (j = 0; j < ef->ddbsymcnt; j++) {
 863                                 es = &ef->ddbsymtab[j];
 864                                 if (es->st_shndx != i)
 865                                         continue;
 866                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 867                         }
 868                         mapbase += shdr[i].sh_size;
 869                         pb++;
 870                         break;
 871                 case SHT_REL:
 872                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 873                             M_WAITOK);
 874                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 875                         ef->reltab[rl].sec = shdr[i].sh_info;
 876                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 877                             (void *)ef->reltab[rl].rel,
 878                             shdr[i].sh_size, shdr[i].sh_offset,
 879                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 880                             &resid, td);
 881                         if (error)
 882                                 goto out;
 883                         if (resid != 0){
 884                                 error = EINVAL;
 885                                 goto out;
 886                         }
 887                         rl++;
 888                         break;
 889                 case SHT_RELA:
 890                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 891                             M_WAITOK);
 892                         ef->relatab[ra].nrela =
 893                             shdr[i].sh_size / sizeof(Elf_Rela);
 894                         ef->relatab[ra].sec = shdr[i].sh_info;
 895                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 896                             (void *)ef->relatab[ra].rela,
 897                             shdr[i].sh_size, shdr[i].sh_offset,
 898                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 899                             &resid, td);
 900                         if (error)
 901                                 goto out;
 902                         if (resid != 0){
 903                                 error = EINVAL;
 904                                 goto out;
 905                         }
 906                         ra++;
 907                         break;
 908                 }
 909         }
 910         if (pb != ef->nprogtab) {
 911                 link_elf_error(filename, "lost progbits");
 912                 error = ENOEXEC;
 913                 goto out;
 914         }
 915         if (rl != ef->nreltab) {
 916                 link_elf_error(filename, "lost reltab");
 917                 error = ENOEXEC;
 918                 goto out;
 919         }
 920         if (ra != ef->nrelatab) {
 921                 link_elf_error(filename, "lost relatab");
 922                 error = ENOEXEC;
 923                 goto out;
 924         }
 925         if (mapbase != (vm_offset_t)ef->address + mapsize) {
 926                 printf(
 927                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 928                     filename != NULL ? filename : "<none>",
 929                     (u_long)mapbase, ef->address, (u_long)mapsize,
 930                     (u_long)(vm_offset_t)ef->address + mapsize);
 931                 error = ENOMEM;
 932                 goto out;
 933         }
 934
 935         /* Local intra-module relocations */
 936         error = link_elf_reloc_local(lf);
 937         if (error != 0)
 938                 goto out;
 939
 940         /* Pull in dependencies */
 941         VOP_UNLOCK(nd->ni_vp, 0);
 942         error = linker_load_dependencies(lf);
 943         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
 944         if (error)
 945                 goto out;
 946
 947         /* External relocations */
 948         error = relocate_file(ef);
 949         if (error)
 950                 goto out;
 951
 952         /* Notify MD code that a module is being loaded. */
 953         error = elf_cpu_load_file(lf);
 954         if (error)
 955                 goto out;
 956
 957         /* Invoke .ctors */
 958         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 959
 960         *result = lf;
 961
 962 out:
 963         VOP_UNLOCK(nd->ni_vp, 0);
 964         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
 965         free(nd, M_TEMP);
 966         if (error && lf)
 967                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 968         free(hdr, M_LINKER);
 969
 970         return error;
 971 }
 972
 973 static void
 974 link_elf_unload_file(linker_file_t file)
 975 {
 976         elf_file_t ef = (elf_file_t) file;
 977         int i;
 978
 979         /* Notify MD code that a module is being unloaded. */
 980         elf_cpu_unload_file(file);
 981
 982         if (ef->progtab) {
 983                 for (i = 0; i < ef->nprogtab; i++) {
 984                         if (ef->progtab[i].size == 0)
 985                                 continue;
 986                         if (ef->progtab[i].name == NULL)
 987                                 continue;
 988                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
 989                                 dpcpu_free(ef->progtab[i].addr,
 990                                     ef->progtab[i].size);
 991 #ifdef VIMAGE
 992                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
 993                                 vnet_data_free(ef->progtab[i].addr,
 994                                     ef->progtab[i].size);
 995 #endif
 996                 }
 997         }
 998         if (ef->preloaded) {
 999                 free(ef->reltab, M_LINKER);
1000                 free(ef->relatab, M_LINKER);
1001                 free(ef->progtab, M_LINKER);
1002                 free(ef->ctftab, M_LINKER);
1003                 free(ef->ctfoff, M_LINKER);
1004                 free(ef->typoff, M_LINKER);
1005                 if (file->filename != NULL)
1006                         preload_delete_name(file->filename);
1007                 /* XXX reclaim module memory? */
1008                 return;
1009         }
1010
1011         for (i = 0; i < ef->nreltab; i++)
1012                 free(ef->reltab[i].rel, M_LINKER);
1013         for (i = 0; i < ef->nrelatab; i++)
1014                 free(ef->relatab[i].rela, M_LINKER);
1015         free(ef->reltab, M_LINKER);
1016         free(ef->relatab, M_LINKER);
1017         free(ef->progtab, M_LINKER);
1018
1019         if (ef->object) {
1020                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1021                     (vm_offset_t) ef->address +
1022                     (ef->object->size << PAGE_SHIFT));
1023         }
1024         free(ef->e_shdr, M_LINKER);
1025         free(ef->ddbsymtab, M_LINKER);
1026         free(ef->ddbstrtab, M_LINKER);
1027         free(ef->shstrtab, M_LINKER);
1028         free(ef->ctftab, M_LINKER);
1029         free(ef->ctfoff, M_LINKER);
1030         free(ef->typoff, M_LINKER);
1031 }
1032
1033 static const char *
1034 symbol_name(elf_file_t ef, Elf_Size r_info)
1035 {
1036         const Elf_Sym *ref;
1037
1038         if (ELF_R_SYM(r_info)) {
1039                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1040                 return ef->ddbstrtab + ref->st_name;
1041         } else
1042                 return NULL;
1043 }
1044
1045 static Elf_Addr
1046 findbase(elf_file_t ef, int sec)
1047 {
1048         int i;
1049         Elf_Addr base = 0;
1050
1051         for (i = 0; i < ef->nprogtab; i++) {
1052                 if (sec == ef->progtab[i].sec) {
1053                         base = (Elf_Addr)ef->progtab[i].addr;
1054                         break;
1055                 }
1056         }
1057         return base;
1058 }
1059
1060 static int
1061 relocate_file(elf_file_t ef)
1062 {
1063         const Elf_Rel *rellim;
1064         const Elf_Rel *rel;
1065         const Elf_Rela *relalim;
1066         const Elf_Rela *rela;
1067         const char *symname;
1068         const Elf_Sym *sym;
1069         int i;
1070         Elf_Size symidx;
1071         Elf_Addr base;
1072
1073
1074         /* Perform relocations without addend if there are any: */
1075         for (i = 0; i < ef->nreltab; i++) {
1076                 rel = ef->reltab[i].rel;
1077                 if (rel == NULL) {
1078                         link_elf_error(ef->lf.filename, "lost a reltab!");
1079                         return (ENOEXEC);
1080                 }
1081                 rellim = rel + ef->reltab[i].nrel;
1082                 base = findbase(ef, ef->reltab[i].sec);
1083                 if (base == 0) {
1084                         link_elf_error(ef->lf.filename, "lost base for reltab");
1085                         return (ENOEXEC);
1086                 }
1087                 for ( ; rel < rellim; rel++) {
1088                         symidx = ELF_R_SYM(rel->r_info);
1089                         if (symidx >= ef->ddbsymcnt)
1090                                 continue;
1091                         sym = ef->ddbsymtab + symidx;
1092                         /* Local relocs are already done */
1093                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1094                                 continue;
1095                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1096                             elf_obj_lookup)) {
1097                                 symname = symbol_name(ef, rel->r_info);
1098                                 printf("link_elf_obj: symbol %s undefined\n",
1099                                     symname);
1100                                 return (ENOENT);
1101                         }
1102                 }
1103         }
1104
1105         /* Perform relocations with addend if there are any: */
1106         for (i = 0; i < ef->nrelatab; i++) {
1107                 rela = ef->relatab[i].rela;
1108                 if (rela == NULL) {
1109                         link_elf_error(ef->lf.filename, "lost a relatab!");
1110                         return (ENOEXEC);
1111                 }
1112                 relalim = rela + ef->relatab[i].nrela;
1113                 base = findbase(ef, ef->relatab[i].sec);
1114                 if (base == 0) {
1115                         link_elf_error(ef->lf.filename,
1116                             "lost base for relatab");
1117                         return (ENOEXEC);
1118                 }
1119                 for ( ; rela < relalim; rela++) {
1120                         symidx = ELF_R_SYM(rela->r_info);
1121                         if (symidx >= ef->ddbsymcnt)
1122                                 continue;
1123                         sym = ef->ddbsymtab + symidx;
1124                         /* Local relocs are already done */
1125                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1126                                 continue;
1127                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1128                             elf_obj_lookup)) {
1129                                 symname = symbol_name(ef, rela->r_info);
1130                                 printf("link_elf_obj: symbol %s undefined\n",
1131                                     symname);
1132                                 return (ENOENT);
1133                         }
1134                 }
1135         }
1136
1137         /*
1138          * Only clean SHN_FBSD_CACHED for successful return.  If we
1139          * modified symbol table for the object but found an
1140          * unresolved symbol, there is no reason to roll back.
1141          */
1142         elf_obj_cleanup_globals_cache(ef);
1143
1144         return (0);
1145 }
1146
1147 static int
1148 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1149 {
1150         elf_file_t ef = (elf_file_t) lf;
1151         const Elf_Sym *symp;
1152         const char *strp;
1153         int i;
1154
1155         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1156                 strp = ef->ddbstrtab + symp->st_name;
1157                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1158                         *sym = (c_linker_sym_t) symp;
1159                         return 0;
1160                 }
1161         }
1162         return ENOENT;
1163 }
1164
1165 static int
1166 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1167     linker_symval_t *symval)
1168 {
1169         elf_file_t ef = (elf_file_t) lf;
1170         const Elf_Sym *es = (const Elf_Sym*) sym;
1171
1172         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1173                 symval->name = ef->ddbstrtab + es->st_name;
1174                 symval->value = (caddr_t)es->st_value;
1175                 symval->size = es->st_size;
1176                 return 0;
1177         }
1178         return ENOENT;
1179 }
1180
1181 static int
1182 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1183     c_linker_sym_t *sym, long *diffp)
1184 {
1185         elf_file_t ef = (elf_file_t) lf;
1186         u_long off = (uintptr_t) (void *) value;
1187         u_long diff = off;
1188         u_long st_value;
1189         const Elf_Sym *es;
1190         const Elf_Sym *best = NULL;
1191         int i;
1192
1193         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1194                 if (es->st_name == 0)
1195                         continue;
1196                 st_value = es->st_value;
1197                 if (off >= st_value) {
1198                         if (off - st_value < diff) {
1199                                 diff = off - st_value;
1200                                 best = es;
1201                                 if (diff == 0)
1202                                         break;
1203                         } else if (off - st_value == diff) {
1204                                 best = es;
1205                         }
1206                 }
1207         }
1208         if (best == NULL)
1209                 *diffp = off;
1210         else
1211                 *diffp = diff;
1212         *sym = (c_linker_sym_t) best;
1213
1214         return 0;
1215 }
1216
1217 /*
1218  * Look up a linker set on an ELF system.
1219  */
1220 static int
1221 link_elf_lookup_set(linker_file_t lf, const char *name,
1222     void ***startp, void ***stopp, int *countp)
1223 {
1224         elf_file_t ef = (elf_file_t)lf;
1225         void **start, **stop;
1226         int i, count;
1227
1228         /* Relative to section number */
1229         for (i = 0; i < ef->nprogtab; i++) {
1230                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1231                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1232                         start  = (void **)ef->progtab[i].addr;
1233                         stop = (void **)((char *)ef->progtab[i].addr +
1234                             ef->progtab[i].size);
1235                         count = stop - start;
1236                         if (startp)
1237                                 *startp = start;
1238                         if (stopp)
1239                                 *stopp = stop;
1240                         if (countp)
1241                                 *countp = count;
1242                         return (0);
1243                 }
1244         }
1245         return (ESRCH);
1246 }
1247
1248 static int
1249 link_elf_each_function_name(linker_file_t file,
1250     int (*callback)(const char *, void *), void *opaque)
1251 {
1252         elf_file_t ef = (elf_file_t)file;
1253         const Elf_Sym *symp;
1254         int i, error;
1255
1256         /* Exhaustive search */
1257         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1258                 if (symp->st_value != 0 &&
1259                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1260                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1261                         if (error)
1262                                 return (error);
1263                 }
1264         }
1265         return (0);
1266 }
1267
1268 static int
1269 link_elf_each_function_nameval(linker_file_t file,
1270     linker_function_nameval_callback_t callback, void *opaque)
1271 {
1272         linker_symval_t symval;
1273         elf_file_t ef = (elf_file_t)file;
1274         const Elf_Sym* symp;
1275         int i, error;
1276
1277         /* Exhaustive search */
1278         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1279                 if (symp->st_value != 0 &&
1280                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1281                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1282                         if (error)
1283                                 return (error);
1284                         error = callback(file, i, &symval, opaque);
1285                         if (error)
1286                                 return (error);
1287                 }
1288         }
1289         return (0);
1290 }
1291
1292 static void
1293 elf_obj_cleanup_globals_cache(elf_file_t ef)
1294 {
1295         Elf_Sym *sym;
1296         Elf_Size i;
1297
1298         for (i = 0; i < ef->ddbsymcnt; i++) {
1299                 sym = ef->ddbsymtab + i;
1300                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1301                         sym->st_shndx = SHN_UNDEF;
1302                         sym->st_value = 0;
1303                 }
1304         }
1305 }
1306
1307 /*
1308  * Symbol lookup function that can be used when the symbol index is known (ie
1309  * in relocations). It uses the symbol index instead of doing a fully fledged
1310  * hash table based lookup when such is valid. For example for local symbols.
1311  * This is not only more efficient, it's also more correct. It's not always
1312  * the case that the symbol can be found through the hash table.
1313  */
1314 static int
1315 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1316 {
1317         elf_file_t ef = (elf_file_t)lf;
1318         Elf_Sym *sym;
1319         const char *symbol;
1320         Elf_Addr res1;
1321
1322         /* Don't even try to lookup the symbol if the index is bogus. */
1323         if (symidx >= ef->ddbsymcnt) {
1324                 *res = 0;
1325                 return (EINVAL);
1326         }
1327
1328         sym = ef->ddbsymtab + symidx;
1329
1330         /* Quick answer if there is a definition included. */
1331         if (sym->st_shndx != SHN_UNDEF) {
1332                 *res = sym->st_value;
1333                 return (0);
1334         }
1335
1336         /* If we get here, then it is undefined and needs a lookup. */
1337         switch (ELF_ST_BIND(sym->st_info)) {
1338         case STB_LOCAL:
1339                 /* Local, but undefined? huh? */
1340                 *res = 0;
1341                 return (EINVAL);
1342
1343         case STB_GLOBAL:
1344         case STB_WEAK:
1345                 /* Relative to Data or Function name */
1346                 symbol = ef->ddbstrtab + sym->st_name;
1347
1348                 /* Force a lookup failure if the symbol name is bogus. */
1349                 if (*symbol == 0) {
1350                         *res = 0;
1351                         return (EINVAL);
1352                 }
1353                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1354
1355                 /*
1356                  * Cache global lookups during module relocation. The failure
1357                  * case is particularly expensive for callers, who must scan
1358                  * through the entire globals table doing strcmp(). Cache to
1359                  * avoid doing such work repeatedly.
1360                  *
1361                  * After relocation is complete, undefined globals will be
1362                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1363                  * above.
1364                  */
1365                 if (res1 != 0) {
1366                         sym->st_shndx = SHN_FBSD_CACHED;
1367                         sym->st_value = res1;
1368                         *res = res1;
1369                         return (0);
1370                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1371                         sym->st_value = 0;
1372                         *res = 0;
1373                         return (0);
1374                 }
1375                 return (EINVAL);
1376
1377         default:
1378                 return (EINVAL);
1379         }
1380 }
1381
1382 static void
1383 link_elf_fix_link_set(elf_file_t ef)
1384 {
1385         static const char startn[] = "__start_";
1386         static const char stopn[] = "__stop_";
1387         Elf_Sym *sym;
1388         const char *sym_name, *linkset_name;
1389         Elf_Addr startp, stopp;
1390         Elf_Size symidx;
1391         int start, i;
1392
1393         startp = stopp = 0;
1394         for (symidx = 1 /* zero entry is special */;
1395                 symidx < ef->ddbsymcnt; symidx++) {
1396                 sym = ef->ddbsymtab + symidx;
1397                 if (sym->st_shndx != SHN_UNDEF)
1398                         continue;
1399
1400                 sym_name = ef->ddbstrtab + sym->st_name;
1401                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1402                         start = 1;
1403                         linkset_name = sym_name + sizeof(startn) - 1;
1404                 }
1405                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1406                         start = 0;
1407                         linkset_name = sym_name + sizeof(stopn) - 1;
1408                 }
1409                 else
1410                         continue;
1411
1412                 for (i = 0; i < ef->nprogtab; i++) {
1413                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1414                                 startp = (Elf_Addr)ef->progtab[i].addr;
1415                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1416                                 break;
1417                         }
1418                 }
1419                 if (i == ef->nprogtab)
1420                         continue;
1421
1422                 sym->st_value = start ? startp : stopp;
1423                 sym->st_shndx = i;
1424         }
1425 }
1426
1427 static int
1428 link_elf_reloc_local(linker_file_t lf)
1429 {
1430         elf_file_t ef = (elf_file_t)lf;
1431         const Elf_Rel *rellim;
1432         const Elf_Rel *rel;
1433         const Elf_Rela *relalim;
1434         const Elf_Rela *rela;
1435         const Elf_Sym *sym;
1436         Elf_Addr base;
1437         int i;
1438         Elf_Size symidx;
1439
1440         link_elf_fix_link_set(ef);
1441
1442         /* Perform relocations without addend if there are any: */
1443         for (i = 0; i < ef->nreltab; i++) {
1444                 rel = ef->reltab[i].rel;
1445                 if (rel == NULL) {
1446                         link_elf_error(ef->lf.filename, "lost a reltab");
1447                         return (ENOEXEC);
1448                 }
1449                 rellim = rel + ef->reltab[i].nrel;
1450                 base = findbase(ef, ef->reltab[i].sec);
1451                 if (base == 0) {
1452                         link_elf_error(ef->lf.filename, "lost base for reltab");
1453                         return (ENOEXEC);
1454                 }
1455                 for ( ; rel < rellim; rel++) {
1456                         symidx = ELF_R_SYM(rel->r_info);
1457                         if (symidx >= ef->ddbsymcnt)
1458                                 continue;
1459                         sym = ef->ddbsymtab + symidx;
1460                         /* Only do local relocs */
1461                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1462                                 continue;
1463                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1464                             elf_obj_lookup);
1465                 }
1466         }
1467
1468         /* Perform relocations with addend if there are any: */
1469         for (i = 0; i < ef->nrelatab; i++) {
1470                 rela = ef->relatab[i].rela;
1471                 if (rela == NULL) {
1472                         link_elf_error(ef->lf.filename, "lost a relatab!");
1473                         return (ENOEXEC);
1474                 }
1475                 relalim = rela + ef->relatab[i].nrela;
1476                 base = findbase(ef, ef->relatab[i].sec);
1477                 if (base == 0) {
1478                         link_elf_error(ef->lf.filename, "lost base for reltab");
1479                         return (ENOEXEC);
1480                 }
1481                 for ( ; rela < relalim; rela++) {
1482                         symidx = ELF_R_SYM(rela->r_info);
1483                         if (symidx >= ef->ddbsymcnt)
1484                                 continue;
1485                         sym = ef->ddbsymtab + symidx;
1486                         /* Only do local relocs */
1487                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1488                                 continue;
1489                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1490                             elf_obj_lookup);
1491                 }
1492         }
1493         return (0);
1494 }
1495
1496 static long
1497 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1498 {
1499     elf_file_t ef = (elf_file_t)lf;
1500
1501     *symtab = ef->ddbsymtab;
1502
1503     if (*symtab == NULL)
1504         return (0);
1505
1506     return (ef->ddbsymcnt);
1507 }
1508
1509 static long
1510 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1511 {
1512     elf_file_t ef = (elf_file_t)lf;
1513
1514     *strtab = ef->ddbstrtab;
1515
1516     if (*strtab == NULL)
1517         return (0);
1518
1519     return (ef->ddbstrcnt);
1520 }