sys/kern/link_elf_obj.c

   1 /*-
   2  * Copyright (c) 1998-2000 Doug Rabson
   3  * Copyright (c) 2004 Peter Wemm
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include "opt_ddb.h"
  32
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/kernel.h>
  36 #include <sys/lock.h>
  37 #include <sys/malloc.h>
  38 #include <sys/mutex.h>
  39 #include <sys/mount.h>
  40 #include <sys/proc.h>
  41 #include <sys/namei.h>
  42 #include <sys/fcntl.h>
  43 #include <sys/vnode.h>
  44 #include <sys/linker.h>
  45
  46 #include <machine/elf.h>
  47
  48 #include <net/vnet.h>
  49
  50 #include <security/mac/mac_framework.h>
  51
  52 #include <vm/vm.h>
  53 #include <vm/vm_param.h>
  54 #include <vm/vm_object.h>
  55 #include <vm/vm_kern.h>
  56 #include <vm/vm_extern.h>
  57 #include <vm/pmap.h>
  58 #include <vm/vm_map.h>
  59
  60 #include <sys/link_elf.h>
  61
  62 #ifdef DDB_CTF
  63 #include <sys/zlib.h>
  64 #endif
  65
  66 #include "linker_if.h"
  67
  68 typedef struct {
  69         void            *addr;
  70         Elf_Off         size;
  71         int             flags;
  72         int             sec;    /* Original section */
  73         char            *name;
  74 } Elf_progent;
  75
  76 typedef struct {
  77         Elf_Rel         *rel;
  78         int             nrel;
  79         int             sec;
  80 } Elf_relent;
  81
  82 typedef struct {
  83         Elf_Rela        *rela;
  84         int             nrela;
  85         int             sec;
  86 } Elf_relaent;
  87
  88
  89 typedef struct elf_file {
  90         struct linker_file lf;          /* Common fields */
  91
  92         int             preloaded;
  93         caddr_t         address;        /* Relocation address */
  94         vm_object_t     object;         /* VM object to hold file pages */
  95         Elf_Shdr        *e_shdr;
  96
  97         Elf_progent     *progtab;
  98         int             nprogtab;
  99
 100         Elf_relaent     *relatab;
 101         int             nrelatab;
 102
 103         Elf_relent      *reltab;
 104         int             nreltab;
 105
 106         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 107         long            ddbsymcnt;      /* Number of symbols */
 108         caddr_t         ddbstrtab;      /* String table */
 109         long            ddbstrcnt;      /* number of bytes in string table */
 110
 111         caddr_t         shstrtab;       /* Section name string table */
 112         long            shstrcnt;       /* number of bytes in string table */
 113
 114         caddr_t         ctftab;         /* CTF table */
 115         long            ctfcnt;         /* number of bytes in CTF table */
 116         caddr_t         ctfoff;         /* CTF offset table */
 117         caddr_t         typoff;         /* Type offset table */
 118         long            typlen;         /* Number of type entries. */
 119
 120 } *elf_file_t;
 121
 122 #include <kern/kern_ctf.c>
 123
 124 static int      link_elf_link_preload(linker_class_t cls,
 125                     const char *, linker_file_t *);
 126 static int      link_elf_link_preload_finish(linker_file_t);
 127 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 128 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 129                     c_linker_sym_t *);
 130 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 131                     linker_symval_t *);
 132 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 133                     c_linker_sym_t *sym, long *diffp);
 134
 135 static void     link_elf_unload_file(linker_file_t);
 136 static int      link_elf_lookup_set(linker_file_t, const char *,
 137                     void ***, void ***, int *);
 138 static int      link_elf_each_function_name(linker_file_t,
 139                     int (*)(const char *, void *), void *);
 140 static int      link_elf_each_function_nameval(linker_file_t,
 141                                 linker_function_nameval_callback_t,
 142                                 void *);
 143 static int      link_elf_reloc_local(linker_file_t);
 144 static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
 145 static long     link_elf_strtab_get(linker_file_t, caddr_t *);
 146
 147 static int      elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
 148                     Elf_Addr *);
 149
 150 static kobj_method_t link_elf_methods[] = {
 151         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 152         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 153         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 154         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 155         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 156         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 157         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 158         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 159         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 160         KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
 161         KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
 162         KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
 163         KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
 164         { 0, 0 }
 165 };
 166
 167 static struct linker_class link_elf_class = {
 168 #if ELF_TARG_CLASS == ELFCLASS32
 169         "elf32_obj",
 170 #else
 171         "elf64_obj",
 172 #endif
 173         link_elf_methods, sizeof(struct elf_file)
 174 };
 175
 176 static int      relocate_file(elf_file_t ef);
 177 static void     elf_obj_cleanup_globals_cache(elf_file_t);
 178
 179 static void
 180 link_elf_error(const char *filename, const char *s)
 181 {
 182         if (filename == NULL)
 183                 printf("kldload: %s\n", s);
 184         else
 185                 printf("kldload: %s: %s\n", filename, s);
 186 }
 187
 188 static void
 189 link_elf_init(void *arg)
 190 {
 191
 192         linker_add_class(&link_elf_class);
 193 }
 194
 195 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
 196
 197 static int
 198 link_elf_link_preload(linker_class_t cls, const char *filename,
 199     linker_file_t *result)
 200 {
 201         Elf_Ehdr *hdr;
 202         Elf_Shdr *shdr;
 203         Elf_Sym *es;
 204         void *modptr, *baseptr, *sizeptr;
 205         char *type;
 206         elf_file_t ef;
 207         linker_file_t lf;
 208         Elf_Addr off;
 209         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 210
 211         /* Look to see if we have the file preloaded */
 212         modptr = preload_search_by_name(filename);
 213         if (modptr == NULL)
 214                 return ENOENT;
 215
 216         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 217         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 218         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 219         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 220             MODINFOMD_ELFHDR);
 221         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 222             MODINFOMD_SHDR);
 223         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 224             " obj module") != 0 &&
 225             strcmp(type, "elf obj module") != 0)) {
 226                 return (EFTYPE);
 227         }
 228         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 229             shdr == NULL)
 230                 return (EINVAL);
 231
 232         lf = linker_make_file(filename, &link_elf_class);
 233         if (lf == NULL)
 234                 return (ENOMEM);
 235
 236         ef = (elf_file_t)lf;
 237         ef->preloaded = 1;
 238         ef->address = *(caddr_t *)baseptr;
 239         lf->address = *(caddr_t *)baseptr;
 240         lf->size = *(size_t *)sizeptr;
 241
 242         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 243             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 244             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 245             hdr->e_version != EV_CURRENT ||
 246             hdr->e_type != ET_REL ||
 247             hdr->e_machine != ELF_TARG_MACH) {
 248                 error = EFTYPE;
 249                 goto out;
 250         }
 251         ef->e_shdr = shdr;
 252
 253         /* Scan the section header for information and table sizing. */
 254         symtabindex = -1;
 255         symstrindex = -1;
 256         for (i = 0; i < hdr->e_shnum; i++) {
 257                 switch (shdr[i].sh_type) {
 258                 case SHT_PROGBITS:
 259                 case SHT_NOBITS:
 260 #ifdef __amd64__
 261                 case SHT_X86_64_UNWIND:
 262 #endif
 263                         ef->nprogtab++;
 264                         break;
 265                 case SHT_SYMTAB:
 266                         symtabindex = i;
 267                         symstrindex = shdr[i].sh_link;
 268                         break;
 269                 case SHT_REL:
 270                         ef->nreltab++;
 271                         break;
 272                 case SHT_RELA:
 273                         ef->nrelatab++;
 274                         break;
 275                 }
 276         }
 277
 278         shstrindex = hdr->e_shstrndx;
 279         if (ef->nprogtab == 0 || symstrindex < 0 ||
 280             symstrindex >= hdr->e_shnum ||
 281             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 282             shstrindex >= hdr->e_shnum ||
 283             shdr[shstrindex].sh_type != SHT_STRTAB) {
 284                 printf("%s: bad/missing section headers\n", filename);
 285                 error = ENOEXEC;
 286                 goto out;
 287         }
 288
 289         /* Allocate space for tracking the load chunks */
 290         if (ef->nprogtab != 0)
 291                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 292                     M_LINKER, M_WAITOK | M_ZERO);
 293         if (ef->nreltab != 0)
 294                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 295                     M_LINKER, M_WAITOK | M_ZERO);
 296         if (ef->nrelatab != 0)
 297                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 298                     M_LINKER, M_WAITOK | M_ZERO);
 299         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 300             (ef->nreltab != 0 && ef->reltab == NULL) ||
 301             (ef->nrelatab != 0 && ef->relatab == NULL)) {
 302                 error = ENOMEM;
 303                 goto out;
 304         }
 305
 306         /* XXX, relocate the sh_addr fields saved by the loader. */
 307         off = 0;
 308         for (i = 0; i < hdr->e_shnum; i++) {
 309                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 310                         off = shdr[i].sh_addr;
 311         }
 312         for (i = 0; i < hdr->e_shnum; i++) {
 313                 if (shdr[i].sh_addr != 0)
 314                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 315                             (Elf_Addr)ef->address;
 316         }
 317
 318         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 319         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 320         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 321         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 322         ef->shstrcnt = shdr[shstrindex].sh_size;
 323         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 324
 325         /* Now fill out progtab and the relocation tables. */
 326         pb = 0;
 327         rl = 0;
 328         ra = 0;
 329         for (i = 0; i < hdr->e_shnum; i++) {
 330                 switch (shdr[i].sh_type) {
 331                 case SHT_PROGBITS:
 332                 case SHT_NOBITS:
 333 #ifdef __amd64__
 334                 case SHT_X86_64_UNWIND:
 335 #endif
 336                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 337                         if (shdr[i].sh_type == SHT_PROGBITS)
 338                                 ef->progtab[pb].name = "<<PROGBITS>>";
 339 #ifdef __amd64__
 340                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 341                                 ef->progtab[pb].name = "<<UNWIND>>";
 342 #endif
 343                         else
 344                                 ef->progtab[pb].name = "<<NOBITS>>";
 345                         ef->progtab[pb].size = shdr[i].sh_size;
 346                         ef->progtab[pb].sec = i;
 347                         if (ef->shstrtab && shdr[i].sh_name != 0)
 348                                 ef->progtab[pb].name =
 349                                     ef->shstrtab + shdr[i].sh_name;
 350                         if (ef->progtab[pb].name != NULL &&
 351                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 352                                 void *dpcpu;
 353
 354                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
 355                                 if (dpcpu == NULL) {
 356                                         error = ENOSPC;
 357                                         goto out;
 358                                 }
 359                                 memcpy(dpcpu, ef->progtab[pb].addr,
 360                                     ef->progtab[pb].size);
 361                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
 362                                 ef->progtab[pb].addr = dpcpu;
 363 #ifdef VIMAGE
 364                         } else if (ef->progtab[pb].name != NULL &&
 365                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 366                                 void *vnet_data;
 367
 368                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
 369                                 if (vnet_data == NULL) {
 370                                         error = ENOSPC;
 371                                         goto out;
 372                                 }
 373                                 memcpy(vnet_data, ef->progtab[pb].addr,
 374                                     ef->progtab[pb].size);
 375                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
 376                                 ef->progtab[pb].addr = vnet_data;
 377 #endif
 378                         } else if (ef->progtab[pb].name != NULL &&
 379                             !strcmp(ef->progtab[pb].name, ".ctors")) {
 380                                 lf->ctors_addr = ef->progtab[pb].addr;
 381                                 lf->ctors_size = shdr[i].sh_size;
 382                         }
 383
 384                         /* Update all symbol values with the offset. */
 385                         for (j = 0; j < ef->ddbsymcnt; j++) {
 386                                 es = &ef->ddbsymtab[j];
 387                                 if (es->st_shndx != i)
 388                                         continue;
 389                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 390                         }
 391                         pb++;
 392                         break;
 393                 case SHT_REL:
 394                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 395                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 396                         ef->reltab[rl].sec = shdr[i].sh_info;
 397                         rl++;
 398                         break;
 399                 case SHT_RELA:
 400                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 401                         ef->relatab[ra].nrela =
 402                             shdr[i].sh_size / sizeof(Elf_Rela);
 403                         ef->relatab[ra].sec = shdr[i].sh_info;
 404                         ra++;
 405                         break;
 406                 }
 407         }
 408         if (pb != ef->nprogtab) {
 409                 printf("%s: lost progbits\n", filename);
 410                 error = ENOEXEC;
 411                 goto out;
 412         }
 413         if (rl != ef->nreltab) {
 414                 printf("%s: lost reltab\n", filename);
 415                 error = ENOEXEC;
 416                 goto out;
 417         }
 418         if (ra != ef->nrelatab) {
 419                 printf("%s: lost relatab\n", filename);
 420                 error = ENOEXEC;
 421                 goto out;
 422         }
 423
 424         /* Local intra-module relocations */
 425         error = link_elf_reloc_local(lf);
 426         if (error != 0)
 427                 goto out;
 428
 429         *result = lf;
 430         return (0);
 431
 432 out:
 433         /* preload not done this way */
 434         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 435         return (error);
 436 }
 437
 438 static void
 439 link_elf_invoke_ctors(caddr_t addr, size_t size)
 440 {
 441         void (**ctor)(void);
 442         size_t i, cnt;
 443
 444         if (addr == NULL || size == 0)
 445                 return;
 446         cnt = size / sizeof(*ctor);
 447         ctor = (void *)addr;
 448         for (i = 0; i < cnt; i++) {
 449                 if (ctor[i] != NULL)
 450                         (*ctor[i])();
 451         }
 452 }
 453
 454 static int
 455 link_elf_link_preload_finish(linker_file_t lf)
 456 {
 457         elf_file_t ef;
 458         int error;
 459
 460         ef = (elf_file_t)lf;
 461         error = relocate_file(ef);
 462         if (error)
 463                 return error;
 464
 465         /* Notify MD code that a module is being loaded. */
 466         error = elf_cpu_load_file(lf);
 467         if (error)
 468                 return (error);
 469
 470         /* Invoke .ctors */
 471         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 472         return (0);
 473 }
 474
 475 static int
 476 link_elf_load_file(linker_class_t cls, const char *filename,
 477     linker_file_t *result)
 478 {
 479         struct nameidata *nd;
 480         struct thread *td = curthread;  /* XXX */
 481         Elf_Ehdr *hdr;
 482         Elf_Shdr *shdr;
 483         Elf_Sym *es;
 484         int nbytes, i, j;
 485         vm_offset_t mapbase;
 486         size_t mapsize;
 487         int error = 0;
 488         ssize_t resid;
 489         int flags;
 490         elf_file_t ef;
 491         linker_file_t lf;
 492         int symtabindex;
 493         int symstrindex;
 494         int shstrindex;
 495         int nsym;
 496         int pb, rl, ra;
 497         int alignmask;
 498
 499         shdr = NULL;
 500         lf = NULL;
 501         mapsize = 0;
 502         hdr = NULL;
 503
 504         nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
 505         NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 506         flags = FREAD;
 507         error = vn_open(nd, &flags, 0, NULL);
 508         if (error) {
 509                 free(nd, M_TEMP);
 510                 return error;
 511         }
 512         NDFREE(nd, NDF_ONLY_PNBUF);
 513         if (nd->ni_vp->v_type != VREG) {
 514                 error = ENOEXEC;
 515                 goto out;
 516         }
 517 #ifdef MAC
 518         error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
 519         if (error) {
 520                 goto out;
 521         }
 522 #endif
 523
 524         /* Read the elf header from the file. */
 525         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 526         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
 527             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 528             &resid, td);
 529         if (error)
 530                 goto out;
 531         if (resid != 0){
 532                 error = ENOEXEC;
 533                 goto out;
 534         }
 535
 536         if (!IS_ELF(*hdr)) {
 537                 error = ENOEXEC;
 538                 goto out;
 539         }
 540
 541         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 542             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 543                 link_elf_error(filename, "Unsupported file layout");
 544                 error = ENOEXEC;
 545                 goto out;
 546         }
 547         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 548             || hdr->e_version != EV_CURRENT) {
 549                 link_elf_error(filename, "Unsupported file version");
 550                 error = ENOEXEC;
 551                 goto out;
 552         }
 553         if (hdr->e_type != ET_REL) {
 554                 error = ENOSYS;
 555                 goto out;
 556         }
 557         if (hdr->e_machine != ELF_TARG_MACH) {
 558                 link_elf_error(filename, "Unsupported machine");
 559                 error = ENOEXEC;
 560                 goto out;
 561         }
 562
 563         lf = linker_make_file(filename, &link_elf_class);
 564         if (!lf) {
 565                 error = ENOMEM;
 566                 goto out;
 567         }
 568         ef = (elf_file_t) lf;
 569         ef->nprogtab = 0;
 570         ef->e_shdr = 0;
 571         ef->nreltab = 0;
 572         ef->nrelatab = 0;
 573
 574         /* Allocate and read in the section header */
 575         nbytes = hdr->e_shnum * hdr->e_shentsize;
 576         if (nbytes == 0 || hdr->e_shoff == 0 ||
 577             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 578                 error = ENOEXEC;
 579                 goto out;
 580         }
 581         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 582         ef->e_shdr = shdr;
 583         error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
 584             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 585             NOCRED, &resid, td);
 586         if (error)
 587                 goto out;
 588         if (resid) {
 589                 error = ENOEXEC;
 590                 goto out;
 591         }
 592
 593         /* Scan the section header for information and table sizing. */
 594         nsym = 0;
 595         symtabindex = -1;
 596         symstrindex = -1;
 597         for (i = 0; i < hdr->e_shnum; i++) {
 598                 if (shdr[i].sh_size == 0)
 599                         continue;
 600                 switch (shdr[i].sh_type) {
 601                 case SHT_PROGBITS:
 602                 case SHT_NOBITS:
 603 #ifdef __amd64__
 604                 case SHT_X86_64_UNWIND:
 605 #endif
 606                         ef->nprogtab++;
 607                         break;
 608                 case SHT_SYMTAB:
 609                         nsym++;
 610                         symtabindex = i;
 611                         symstrindex = shdr[i].sh_link;
 612                         break;
 613                 case SHT_REL:
 614                         ef->nreltab++;
 615                         break;
 616                 case SHT_RELA:
 617                         ef->nrelatab++;
 618                         break;
 619                 case SHT_STRTAB:
 620                         break;
 621                 }
 622         }
 623         if (ef->nprogtab == 0) {
 624                 link_elf_error(filename, "file has no contents");
 625                 error = ENOEXEC;
 626                 goto out;
 627         }
 628         if (nsym != 1) {
 629                 /* Only allow one symbol table for now */
 630                 link_elf_error(filename, "file has no valid symbol table");
 631                 error = ENOEXEC;
 632                 goto out;
 633         }
 634         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 635             shdr[symstrindex].sh_type != SHT_STRTAB) {
 636                 link_elf_error(filename, "file has invalid symbol strings");
 637                 error = ENOEXEC;
 638                 goto out;
 639         }
 640
 641         /* Allocate space for tracking the load chunks */
 642         if (ef->nprogtab != 0)
 643                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 644                     M_LINKER, M_WAITOK | M_ZERO);
 645         if (ef->nreltab != 0)
 646                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 647                     M_LINKER, M_WAITOK | M_ZERO);
 648         if (ef->nrelatab != 0)
 649                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 650                     M_LINKER, M_WAITOK | M_ZERO);
 651
 652         if (symtabindex == -1) {
 653                 link_elf_error(filename, "lost symbol table index");
 654                 error = ENOEXEC;
 655                 goto out;
 656         }
 657         /* Allocate space for and load the symbol table */
 658         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 659         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 660         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 661             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 662             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 663             &resid, td);
 664         if (error)
 665                 goto out;
 666         if (resid != 0){
 667                 error = EINVAL;
 668                 goto out;
 669         }
 670
 671         if (symstrindex == -1) {
 672                 link_elf_error(filename, "lost symbol string index");
 673                 error = ENOEXEC;
 674                 goto out;
 675         }
 676         /* Allocate space for and load the symbol strings */
 677         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 678         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 679         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 680             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 681             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 682             &resid, td);
 683         if (error)
 684                 goto out;
 685         if (resid != 0){
 686                 error = EINVAL;
 687                 goto out;
 688         }
 689
 690         /* Do we have a string table for the section names?  */
 691         shstrindex = -1;
 692         if (hdr->e_shstrndx != 0 &&
 693             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 694                 shstrindex = hdr->e_shstrndx;
 695                 ef->shstrcnt = shdr[shstrindex].sh_size;
 696                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 697                     M_WAITOK);
 698                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 699                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 700                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 701                     &resid, td);
 702                 if (error)
 703                         goto out;
 704                 if (resid != 0){
 705                         error = EINVAL;
 706                         goto out;
 707                 }
 708         }
 709
 710         /* Size up code/data(progbits) and bss(nobits). */
 711         alignmask = 0;
 712         for (i = 0; i < hdr->e_shnum; i++) {
 713                 if (shdr[i].sh_size == 0)
 714                         continue;
 715                 switch (shdr[i].sh_type) {
 716                 case SHT_PROGBITS:
 717                 case SHT_NOBITS:
 718 #ifdef __amd64__
 719                 case SHT_X86_64_UNWIND:
 720 #endif
 721                         alignmask = shdr[i].sh_addralign - 1;
 722                         mapsize += alignmask;
 723                         mapsize &= ~alignmask;
 724                         mapsize += shdr[i].sh_size;
 725                         break;
 726                 }
 727         }
 728
 729         /*
 730          * We know how much space we need for the text/data/bss/etc.
 731          * This stuff needs to be in a single chunk so that profiling etc
 732          * can get the bounds and gdb can associate offsets with modules
 733          */
 734         ef->object = vm_object_allocate(OBJT_DEFAULT,
 735             round_page(mapsize) >> PAGE_SHIFT);
 736         if (ef->object == NULL) {
 737                 error = ENOMEM;
 738                 goto out;
 739         }
 740         ef->address = (caddr_t) vm_map_min(kernel_map);
 741
 742         /*
 743          * In order to satisfy amd64's architectural requirements on the
 744          * location of code and data in the kernel's address space, request a
 745          * mapping that is above the kernel.
 746          */
 747 #ifdef __amd64__
 748         mapbase = KERNBASE;
 749 #else
 750         mapbase = VM_MIN_KERNEL_ADDRESS;
 751 #endif
 752         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 753             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 754             VM_PROT_ALL, 0);
 755         if (error) {
 756                 vm_object_deallocate(ef->object);
 757                 ef->object = 0;
 758                 goto out;
 759         }
 760
 761         /* Wire the pages */
 762         error = vm_map_wire(kernel_map, mapbase,
 763             mapbase + round_page(mapsize),
 764             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 765         if (error != KERN_SUCCESS) {
 766                 error = ENOMEM;
 767                 goto out;
 768         }
 769
 770         /* Inform the kld system about the situation */
 771         lf->address = ef->address = (caddr_t)mapbase;
 772         lf->size = mapsize;
 773
 774         /*
 775          * Now load code/data(progbits), zero bss(nobits), allocate space for
 776          * and load relocs
 777          */
 778         pb = 0;
 779         rl = 0;
 780         ra = 0;
 781         alignmask = 0;
 782         for (i = 0; i < hdr->e_shnum; i++) {
 783                 if (shdr[i].sh_size == 0)
 784                         continue;
 785                 switch (shdr[i].sh_type) {
 786                 case SHT_PROGBITS:
 787                 case SHT_NOBITS:
 788 #ifdef __amd64__
 789                 case SHT_X86_64_UNWIND:
 790 #endif
 791                         alignmask = shdr[i].sh_addralign - 1;
 792                         mapbase += alignmask;
 793                         mapbase &= ~alignmask;
 794                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 795                                 ef->progtab[pb].name =
 796                                     ef->shstrtab + shdr[i].sh_name;
 797                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 798                                         lf->ctors_addr = (caddr_t)mapbase;
 799                                         lf->ctors_size = shdr[i].sh_size;
 800                                 }
 801                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 802                                 ef->progtab[pb].name = "<<PROGBITS>>";
 803 #ifdef __amd64__
 804                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 805                                 ef->progtab[pb].name = "<<UNWIND>>";
 806 #endif
 807                         else
 808                                 ef->progtab[pb].name = "<<NOBITS>>";
 809                         if (ef->progtab[pb].name != NULL &&
 810                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 811                                 ef->progtab[pb].addr =
 812                                     dpcpu_alloc(shdr[i].sh_size);
 813 #ifdef VIMAGE
 814                         else if (ef->progtab[pb].name != NULL &&
 815                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 816                                 ef->progtab[pb].addr =
 817                                     vnet_data_alloc(shdr[i].sh_size);
 818 #endif
 819                         else
 820                                 ef->progtab[pb].addr =
 821                                     (void *)(uintptr_t)mapbase;
 822                         if (ef->progtab[pb].addr == NULL) {
 823                                 error = ENOSPC;
 824                                 goto out;
 825                         }
 826                         ef->progtab[pb].size = shdr[i].sh_size;
 827                         ef->progtab[pb].sec = i;
 828                         if (shdr[i].sh_type == SHT_PROGBITS
 829 #ifdef __amd64__
 830                             || shdr[i].sh_type == SHT_X86_64_UNWIND
 831 #endif
 832                             ) {
 833                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
 834                                     ef->progtab[pb].addr,
 835                                     shdr[i].sh_size, shdr[i].sh_offset,
 836                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 837                                     NOCRED, &resid, td);
 838                                 if (error)
 839                                         goto out;
 840                                 if (resid != 0){
 841                                         error = EINVAL;
 842                                         goto out;
 843                                 }
 844                                 /* Initialize the per-cpu or vnet area. */
 845                                 if (ef->progtab[pb].addr != (void *)mapbase &&
 846                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 847                                         dpcpu_copy(ef->progtab[pb].addr,
 848                                             shdr[i].sh_size);
 849 #ifdef VIMAGE
 850                                 else if (ef->progtab[pb].addr !=
 851                                     (void *)mapbase &&
 852                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 853                                         vnet_data_copy(ef->progtab[pb].addr,
 854                                             shdr[i].sh_size);
 855 #endif
 856                         } else
 857                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 858
 859                         /* Update all symbol values with the offset. */
 860                         for (j = 0; j < ef->ddbsymcnt; j++) {
 861                                 es = &ef->ddbsymtab[j];
 862                                 if (es->st_shndx != i)
 863                                         continue;
 864                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 865                         }
 866                         mapbase += shdr[i].sh_size;
 867                         pb++;
 868                         break;
 869                 case SHT_REL:
 870                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 871                             M_WAITOK);
 872                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 873                         ef->reltab[rl].sec = shdr[i].sh_info;
 874                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 875                             (void *)ef->reltab[rl].rel,
 876                             shdr[i].sh_size, shdr[i].sh_offset,
 877                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 878                             &resid, td);
 879                         if (error)
 880                                 goto out;
 881                         if (resid != 0){
 882                                 error = EINVAL;
 883                                 goto out;
 884                         }
 885                         rl++;
 886                         break;
 887                 case SHT_RELA:
 888                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 889                             M_WAITOK);
 890                         ef->relatab[ra].nrela =
 891                             shdr[i].sh_size / sizeof(Elf_Rela);
 892                         ef->relatab[ra].sec = shdr[i].sh_info;
 893                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 894                             (void *)ef->relatab[ra].rela,
 895                             shdr[i].sh_size, shdr[i].sh_offset,
 896                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 897                             &resid, td);
 898                         if (error)
 899                                 goto out;
 900                         if (resid != 0){
 901                                 error = EINVAL;
 902                                 goto out;
 903                         }
 904                         ra++;
 905                         break;
 906                 }
 907         }
 908         if (pb != ef->nprogtab) {
 909                 link_elf_error(filename, "lost progbits");
 910                 error = ENOEXEC;
 911                 goto out;
 912         }
 913         if (rl != ef->nreltab) {
 914                 link_elf_error(filename, "lost reltab");
 915                 error = ENOEXEC;
 916                 goto out;
 917         }
 918         if (ra != ef->nrelatab) {
 919                 link_elf_error(filename, "lost relatab");
 920                 error = ENOEXEC;
 921                 goto out;
 922         }
 923         if (mapbase != (vm_offset_t)ef->address + mapsize) {
 924                 printf(
 925                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 926                     filename != NULL ? filename : "<none>",
 927                     (u_long)mapbase, ef->address, (u_long)mapsize,
 928                     (u_long)(vm_offset_t)ef->address + mapsize);
 929                 error = ENOMEM;
 930                 goto out;
 931         }
 932
 933         /* Local intra-module relocations */
 934         error = link_elf_reloc_local(lf);
 935         if (error != 0)
 936                 goto out;
 937
 938         /* Pull in dependencies */
 939         VOP_UNLOCK(nd->ni_vp, 0);
 940         error = linker_load_dependencies(lf);
 941         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
 942         if (error)
 943                 goto out;
 944
 945         /* External relocations */
 946         error = relocate_file(ef);
 947         if (error)
 948                 goto out;
 949
 950         /* Notify MD code that a module is being loaded. */
 951         error = elf_cpu_load_file(lf);
 952         if (error)
 953                 goto out;
 954
 955         /* Invoke .ctors */
 956         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 957
 958         *result = lf;
 959
 960 out:
 961         VOP_UNLOCK(nd->ni_vp, 0);
 962         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
 963         free(nd, M_TEMP);
 964         if (error && lf)
 965                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 966         free(hdr, M_LINKER);
 967
 968         return error;
 969 }
 970
 971 static void
 972 link_elf_unload_file(linker_file_t file)
 973 {
 974         elf_file_t ef = (elf_file_t) file;
 975         int i;
 976
 977         /* Notify MD code that a module is being unloaded. */
 978         elf_cpu_unload_file(file);
 979
 980         if (ef->progtab) {
 981                 for (i = 0; i < ef->nprogtab; i++) {
 982                         if (ef->progtab[i].size == 0)
 983                                 continue;
 984                         if (ef->progtab[i].name == NULL)
 985                                 continue;
 986                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
 987                                 dpcpu_free(ef->progtab[i].addr,
 988                                     ef->progtab[i].size);
 989 #ifdef VIMAGE
 990                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
 991                                 vnet_data_free(ef->progtab[i].addr,
 992                                     ef->progtab[i].size);
 993 #endif
 994                 }
 995         }
 996         if (ef->preloaded) {
 997                 free(ef->reltab, M_LINKER);
 998                 free(ef->relatab, M_LINKER);
 999                 free(ef->progtab, M_LINKER);
1000                 free(ef->ctftab, M_LINKER);
1001                 free(ef->ctfoff, M_LINKER);
1002                 free(ef->typoff, M_LINKER);
1003                 if (file->filename != NULL)
1004                         preload_delete_name(file->filename);
1005                 /* XXX reclaim module memory? */
1006                 return;
1007         }
1008
1009         for (i = 0; i < ef->nreltab; i++)
1010                 free(ef->reltab[i].rel, M_LINKER);
1011         for (i = 0; i < ef->nrelatab; i++)
1012                 free(ef->relatab[i].rela, M_LINKER);
1013         free(ef->reltab, M_LINKER);
1014         free(ef->relatab, M_LINKER);
1015         free(ef->progtab, M_LINKER);
1016
1017         if (ef->object) {
1018                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1019                     (vm_offset_t) ef->address +
1020                     (ef->object->size << PAGE_SHIFT));
1021         }
1022         free(ef->e_shdr, M_LINKER);
1023         free(ef->ddbsymtab, M_LINKER);
1024         free(ef->ddbstrtab, M_LINKER);
1025         free(ef->shstrtab, M_LINKER);
1026         free(ef->ctftab, M_LINKER);
1027         free(ef->ctfoff, M_LINKER);
1028         free(ef->typoff, M_LINKER);
1029 }
1030
1031 static const char *
1032 symbol_name(elf_file_t ef, Elf_Size r_info)
1033 {
1034         const Elf_Sym *ref;
1035
1036         if (ELF_R_SYM(r_info)) {
1037                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1038                 return ef->ddbstrtab + ref->st_name;
1039         } else
1040                 return NULL;
1041 }
1042
1043 static Elf_Addr
1044 findbase(elf_file_t ef, int sec)
1045 {
1046         int i;
1047         Elf_Addr base = 0;
1048
1049         for (i = 0; i < ef->nprogtab; i++) {
1050                 if (sec == ef->progtab[i].sec) {
1051                         base = (Elf_Addr)ef->progtab[i].addr;
1052                         break;
1053                 }
1054         }
1055         return base;
1056 }
1057
1058 static int
1059 relocate_file(elf_file_t ef)
1060 {
1061         const Elf_Rel *rellim;
1062         const Elf_Rel *rel;
1063         const Elf_Rela *relalim;
1064         const Elf_Rela *rela;
1065         const char *symname;
1066         const Elf_Sym *sym;
1067         int i;
1068         Elf_Size symidx;
1069         Elf_Addr base;
1070
1071
1072         /* Perform relocations without addend if there are any: */
1073         for (i = 0; i < ef->nreltab; i++) {
1074                 rel = ef->reltab[i].rel;
1075                 if (rel == NULL) {
1076                         link_elf_error(ef->lf.filename, "lost a reltab!");
1077                         return (ENOEXEC);
1078                 }
1079                 rellim = rel + ef->reltab[i].nrel;
1080                 base = findbase(ef, ef->reltab[i].sec);
1081                 if (base == 0) {
1082                         link_elf_error(ef->lf.filename, "lost base for reltab");
1083                         return (ENOEXEC);
1084                 }
1085                 for ( ; rel < rellim; rel++) {
1086                         symidx = ELF_R_SYM(rel->r_info);
1087                         if (symidx >= ef->ddbsymcnt)
1088                                 continue;
1089                         sym = ef->ddbsymtab + symidx;
1090                         /* Local relocs are already done */
1091                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1092                                 continue;
1093                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1094                             elf_obj_lookup)) {
1095                                 symname = symbol_name(ef, rel->r_info);
1096                                 printf("link_elf_obj: symbol %s undefined\n",
1097                                     symname);
1098                                 return (ENOENT);
1099                         }
1100                 }
1101         }
1102
1103         /* Perform relocations with addend if there are any: */
1104         for (i = 0; i < ef->nrelatab; i++) {
1105                 rela = ef->relatab[i].rela;
1106                 if (rela == NULL) {
1107                         link_elf_error(ef->lf.filename, "lost a relatab!");
1108                         return (ENOEXEC);
1109                 }
1110                 relalim = rela + ef->relatab[i].nrela;
1111                 base = findbase(ef, ef->relatab[i].sec);
1112                 if (base == 0) {
1113                         link_elf_error(ef->lf.filename,
1114                             "lost base for relatab");
1115                         return (ENOEXEC);
1116                 }
1117                 for ( ; rela < relalim; rela++) {
1118                         symidx = ELF_R_SYM(rela->r_info);
1119                         if (symidx >= ef->ddbsymcnt)
1120                                 continue;
1121                         sym = ef->ddbsymtab + symidx;
1122                         /* Local relocs are already done */
1123                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1124                                 continue;
1125                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1126                             elf_obj_lookup)) {
1127                                 symname = symbol_name(ef, rela->r_info);
1128                                 printf("link_elf_obj: symbol %s undefined\n",
1129                                     symname);
1130                                 return (ENOENT);
1131                         }
1132                 }
1133         }
1134
1135         /*
1136          * Only clean SHN_FBSD_CACHED for successful return.  If we
1137          * modified symbol table for the object but found an
1138          * unresolved symbol, there is no reason to roll back.
1139          */
1140         elf_obj_cleanup_globals_cache(ef);
1141
1142         return (0);
1143 }
1144
1145 static int
1146 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1147 {
1148         elf_file_t ef = (elf_file_t) lf;
1149         const Elf_Sym *symp;
1150         const char *strp;
1151         int i;
1152
1153         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1154                 strp = ef->ddbstrtab + symp->st_name;
1155                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1156                         *sym = (c_linker_sym_t) symp;
1157                         return 0;
1158                 }
1159         }
1160         return ENOENT;
1161 }
1162
1163 static int
1164 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1165     linker_symval_t *symval)
1166 {
1167         elf_file_t ef = (elf_file_t) lf;
1168         const Elf_Sym *es = (const Elf_Sym*) sym;
1169
1170         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1171                 symval->name = ef->ddbstrtab + es->st_name;
1172                 symval->value = (caddr_t)es->st_value;
1173                 symval->size = es->st_size;
1174                 return 0;
1175         }
1176         return ENOENT;
1177 }
1178
1179 static int
1180 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1181     c_linker_sym_t *sym, long *diffp)
1182 {
1183         elf_file_t ef = (elf_file_t) lf;
1184         u_long off = (uintptr_t) (void *) value;
1185         u_long diff = off;
1186         u_long st_value;
1187         const Elf_Sym *es;
1188         const Elf_Sym *best = NULL;
1189         int i;
1190
1191         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1192                 if (es->st_name == 0)
1193                         continue;
1194                 st_value = es->st_value;
1195                 if (off >= st_value) {
1196                         if (off - st_value < diff) {
1197                                 diff = off - st_value;
1198                                 best = es;
1199                                 if (diff == 0)
1200                                         break;
1201                         } else if (off - st_value == diff) {
1202                                 best = es;
1203                         }
1204                 }
1205         }
1206         if (best == NULL)
1207                 *diffp = off;
1208         else
1209                 *diffp = diff;
1210         *sym = (c_linker_sym_t) best;
1211
1212         return 0;
1213 }
1214
1215 /*
1216  * Look up a linker set on an ELF system.
1217  */
1218 static int
1219 link_elf_lookup_set(linker_file_t lf, const char *name,
1220     void ***startp, void ***stopp, int *countp)
1221 {
1222         elf_file_t ef = (elf_file_t)lf;
1223         void **start, **stop;
1224         int i, count;
1225
1226         /* Relative to section number */
1227         for (i = 0; i < ef->nprogtab; i++) {
1228                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1229                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1230                         start  = (void **)ef->progtab[i].addr;
1231                         stop = (void **)((char *)ef->progtab[i].addr +
1232                             ef->progtab[i].size);
1233                         count = stop - start;
1234                         if (startp)
1235                                 *startp = start;
1236                         if (stopp)
1237                                 *stopp = stop;
1238                         if (countp)
1239                                 *countp = count;
1240                         return (0);
1241                 }
1242         }
1243         return (ESRCH);
1244 }
1245
1246 static int
1247 link_elf_each_function_name(linker_file_t file,
1248     int (*callback)(const char *, void *), void *opaque)
1249 {
1250         elf_file_t ef = (elf_file_t)file;
1251         const Elf_Sym *symp;
1252         int i, error;
1253
1254         /* Exhaustive search */
1255         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1256                 if (symp->st_value != 0 &&
1257                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1258                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1259                         if (error)
1260                                 return (error);
1261                 }
1262         }
1263         return (0);
1264 }
1265
1266 static int
1267 link_elf_each_function_nameval(linker_file_t file,
1268     linker_function_nameval_callback_t callback, void *opaque)
1269 {
1270         linker_symval_t symval;
1271         elf_file_t ef = (elf_file_t)file;
1272         const Elf_Sym* symp;
1273         int i, error;
1274
1275         /* Exhaustive search */
1276         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1277                 if (symp->st_value != 0 &&
1278                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1279                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1280                         if (error)
1281                                 return (error);
1282                         error = callback(file, i, &symval, opaque);
1283                         if (error)
1284                                 return (error);
1285                 }
1286         }
1287         return (0);
1288 }
1289
1290 static void
1291 elf_obj_cleanup_globals_cache(elf_file_t ef)
1292 {
1293         Elf_Sym *sym;
1294         Elf_Size i;
1295
1296         for (i = 0; i < ef->ddbsymcnt; i++) {
1297                 sym = ef->ddbsymtab + i;
1298                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1299                         sym->st_shndx = SHN_UNDEF;
1300                         sym->st_value = 0;
1301                 }
1302         }
1303 }
1304
1305 /*
1306  * Symbol lookup function that can be used when the symbol index is known (ie
1307  * in relocations). It uses the symbol index instead of doing a fully fledged
1308  * hash table based lookup when such is valid. For example for local symbols.
1309  * This is not only more efficient, it's also more correct. It's not always
1310  * the case that the symbol can be found through the hash table.
1311  */
1312 static int
1313 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1314 {
1315         elf_file_t ef = (elf_file_t)lf;
1316         Elf_Sym *sym;
1317         const char *symbol;
1318         Elf_Addr res1;
1319
1320         /* Don't even try to lookup the symbol if the index is bogus. */
1321         if (symidx >= ef->ddbsymcnt) {
1322                 *res = 0;
1323                 return (EINVAL);
1324         }
1325
1326         sym = ef->ddbsymtab + symidx;
1327
1328         /* Quick answer if there is a definition included. */
1329         if (sym->st_shndx != SHN_UNDEF) {
1330                 *res = sym->st_value;
1331                 return (0);
1332         }
1333
1334         /* If we get here, then it is undefined and needs a lookup. */
1335         switch (ELF_ST_BIND(sym->st_info)) {
1336         case STB_LOCAL:
1337                 /* Local, but undefined? huh? */
1338                 *res = 0;
1339                 return (EINVAL);
1340
1341         case STB_GLOBAL:
1342         case STB_WEAK:
1343                 /* Relative to Data or Function name */
1344                 symbol = ef->ddbstrtab + sym->st_name;
1345
1346                 /* Force a lookup failure if the symbol name is bogus. */
1347                 if (*symbol == 0) {
1348                         *res = 0;
1349                         return (EINVAL);
1350                 }
1351                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1352
1353                 /*
1354                  * Cache global lookups during module relocation. The failure
1355                  * case is particularly expensive for callers, who must scan
1356                  * through the entire globals table doing strcmp(). Cache to
1357                  * avoid doing such work repeatedly.
1358                  *
1359                  * After relocation is complete, undefined globals will be
1360                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1361                  * above.
1362                  */
1363                 if (res1 != 0) {
1364                         sym->st_shndx = SHN_FBSD_CACHED;
1365                         sym->st_value = res1;
1366                         *res = res1;
1367                         return (0);
1368                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1369                         sym->st_value = 0;
1370                         *res = 0;
1371                         return (0);
1372                 }
1373                 return (EINVAL);
1374
1375         default:
1376                 return (EINVAL);
1377         }
1378 }
1379
1380 static void
1381 link_elf_fix_link_set(elf_file_t ef)
1382 {
1383         static const char startn[] = "__start_";
1384         static const char stopn[] = "__stop_";
1385         Elf_Sym *sym;
1386         const char *sym_name, *linkset_name;
1387         Elf_Addr startp, stopp;
1388         Elf_Size symidx;
1389         int start, i;
1390
1391         startp = stopp = 0;
1392         for (symidx = 1 /* zero entry is special */;
1393                 symidx < ef->ddbsymcnt; symidx++) {
1394                 sym = ef->ddbsymtab + symidx;
1395                 if (sym->st_shndx != SHN_UNDEF)
1396                         continue;
1397
1398                 sym_name = ef->ddbstrtab + sym->st_name;
1399                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1400                         start = 1;
1401                         linkset_name = sym_name + sizeof(startn) - 1;
1402                 }
1403                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1404                         start = 0;
1405                         linkset_name = sym_name + sizeof(stopn) - 1;
1406                 }
1407                 else
1408                         continue;
1409
1410                 for (i = 0; i < ef->nprogtab; i++) {
1411                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1412                                 startp = (Elf_Addr)ef->progtab[i].addr;
1413                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1414                                 break;
1415                         }
1416                 }
1417                 if (i == ef->nprogtab)
1418                         continue;
1419
1420                 sym->st_value = start ? startp : stopp;
1421                 sym->st_shndx = i;
1422         }
1423 }
1424
1425 static int
1426 link_elf_reloc_local(linker_file_t lf)
1427 {
1428         elf_file_t ef = (elf_file_t)lf;
1429         const Elf_Rel *rellim;
1430         const Elf_Rel *rel;
1431         const Elf_Rela *relalim;
1432         const Elf_Rela *rela;
1433         const Elf_Sym *sym;
1434         Elf_Addr base;
1435         int i;
1436         Elf_Size symidx;
1437
1438         link_elf_fix_link_set(ef);
1439
1440         /* Perform relocations without addend if there are any: */
1441         for (i = 0; i < ef->nreltab; i++) {
1442                 rel = ef->reltab[i].rel;
1443                 if (rel == NULL) {
1444                         link_elf_error(ef->lf.filename, "lost a reltab");
1445                         return (ENOEXEC);
1446                 }
1447                 rellim = rel + ef->reltab[i].nrel;
1448                 base = findbase(ef, ef->reltab[i].sec);
1449                 if (base == 0) {
1450                         link_elf_error(ef->lf.filename, "lost base for reltab");
1451                         return (ENOEXEC);
1452                 }
1453                 for ( ; rel < rellim; rel++) {
1454                         symidx = ELF_R_SYM(rel->r_info);
1455                         if (symidx >= ef->ddbsymcnt)
1456                                 continue;
1457                         sym = ef->ddbsymtab + symidx;
1458                         /* Only do local relocs */
1459                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1460                                 continue;
1461                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1462                             elf_obj_lookup);
1463                 }
1464         }
1465
1466         /* Perform relocations with addend if there are any: */
1467         for (i = 0; i < ef->nrelatab; i++) {
1468                 rela = ef->relatab[i].rela;
1469                 if (rela == NULL) {
1470                         link_elf_error(ef->lf.filename, "lost a relatab!");
1471                         return (ENOEXEC);
1472                 }
1473                 relalim = rela + ef->relatab[i].nrela;
1474                 base = findbase(ef, ef->relatab[i].sec);
1475                 if (base == 0) {
1476                         link_elf_error(ef->lf.filename, "lost base for reltab");
1477                         return (ENOEXEC);
1478                 }
1479                 for ( ; rela < relalim; rela++) {
1480                         symidx = ELF_R_SYM(rela->r_info);
1481                         if (symidx >= ef->ddbsymcnt)
1482                                 continue;
1483                         sym = ef->ddbsymtab + symidx;
1484                         /* Only do local relocs */
1485                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1486                                 continue;
1487                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1488                             elf_obj_lookup);
1489                 }
1490         }
1491         return (0);
1492 }
1493
1494 static long
1495 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1496 {
1497     elf_file_t ef = (elf_file_t)lf;
1498
1499     *symtab = ef->ddbsymtab;
1500
1501     if (*symtab == NULL)
1502         return (0);
1503
1504     return (ef->ddbsymcnt);
1505 }
1506
1507 static long
1508 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1509 {
1510     elf_file_t ef = (elf_file_t)lf;
1511
1512     *strtab = ef->ddbstrtab;
1513
1514     if (*strtab == NULL)
1515         return (0);
1516
1517     return (ef->ddbstrcnt);
1518 }