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 #include "opt_mac.h"
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/lock.h>
  38 #include <sys/mac.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/proc.h>
  42 #include <sys/namei.h>
  43 #include <sys/fcntl.h>
  44 #include <sys/vnode.h>
  45 #include <sys/linker.h>
  46
  47 #include <machine/elf.h>
  48
  49 #include <vm/vm.h>
  50 #include <vm/vm_param.h>
  51 #include <vm/vm_object.h>
  52 #include <vm/vm_kern.h>
  53 #include <vm/vm_extern.h>
  54 #include <vm/pmap.h>
  55 #include <vm/vm_map.h>
  56
  57 #include <sys/link_elf.h>
  58
  59 #include "linker_if.h"
  60
  61 typedef struct {
  62         void            *addr;
  63         Elf_Off         size;
  64         int             flags;
  65         int             sec;    /* Original section */
  66         char            *name;
  67 } Elf_progent;
  68
  69 typedef struct {
  70         Elf_Rel         *rel;
  71         int             nrel;
  72         int             sec;
  73 } Elf_relent;
  74
  75 typedef struct {
  76         Elf_Rela        *rela;
  77         int             nrela;
  78         int             sec;
  79 } Elf_relaent;
  80
  81
  82 typedef struct elf_file {
  83         struct linker_file lf;          /* Common fields */
  84
  85         int             preloaded;
  86         caddr_t         address;        /* Relocation address */
  87         vm_object_t     object;         /* VM object to hold file pages */
  88         Elf_Shdr        *e_shdr;
  89
  90         Elf_progent     *progtab;
  91         int             nprogtab;
  92
  93         Elf_relaent     *relatab;
  94         int             nrela;
  95
  96         Elf_relent      *reltab;
  97         int             nrel;
  98
  99         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 100         long            ddbsymcnt;      /* Number of symbols */
 101         caddr_t         ddbstrtab;      /* String table */
 102         long            ddbstrcnt;      /* number of bytes in string table */
 103
 104         caddr_t         shstrtab;       /* Section name string table */
 105         long            shstrcnt;       /* number of bytes in string table */
 106
 107 } *elf_file_t;
 108
 109 static int      link_elf_link_preload(linker_class_t cls,
 110                     const char *, linker_file_t *);
 111 static int      link_elf_link_preload_finish(linker_file_t);
 112 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 113 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 114                     c_linker_sym_t *);
 115 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 116                     linker_symval_t *);
 117 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 118                     c_linker_sym_t *sym, long *diffp);
 119
 120 static void     link_elf_unload_file(linker_file_t);
 121 static int      link_elf_lookup_set(linker_file_t, const char *,
 122                     void ***, void ***, int *);
 123 static int      link_elf_each_function_name(linker_file_t,
 124                     int (*)(const char *, void *), void *);
 125 static void     link_elf_reloc_local(linker_file_t);
 126
 127 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Word symidx, int deps);
 128
 129 static kobj_method_t link_elf_methods[] = {
 130         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 131         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 132         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 133         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 134         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 135         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 136         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 137         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 138         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 139         { 0, 0 }
 140 };
 141
 142 static struct linker_class link_elf_class = {
 143 #if ELF_TARG_CLASS == ELFCLASS32
 144         "elf32_obj",
 145 #else
 146         "elf64_obj",
 147 #endif
 148         link_elf_methods, sizeof(struct elf_file)
 149 };
 150
 151 static int      relocate_file(elf_file_t ef);
 152
 153 static void
 154 link_elf_error(const char *s)
 155 {
 156         printf("kldload: %s\n", s);
 157 }
 158
 159 static void
 160 link_elf_init(void *arg)
 161 {
 162
 163         linker_add_class(&link_elf_class);
 164 }
 165
 166 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
 167
 168 static int
 169 link_elf_link_preload(linker_class_t cls, const char *filename,
 170     linker_file_t *result)
 171 {
 172         Elf_Ehdr *hdr;
 173         Elf_Shdr *shdr;
 174         Elf_Sym *es;
 175         void *modptr, *baseptr, *sizeptr;
 176         char *type;
 177         elf_file_t ef;
 178         linker_file_t lf;
 179         Elf_Addr off;
 180         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 181
 182         /* Look to see if we have the file preloaded */
 183         modptr = preload_search_by_name(filename);
 184         if (modptr == NULL)
 185                 return ENOENT;
 186
 187         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 188         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 189         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 190         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 191             MODINFOMD_ELFHDR);
 192         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 193             MODINFOMD_SHDR);
 194         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 195             " obj module") != 0 &&
 196             strcmp(type, "elf obj module") != 0)) {
 197                 return (EFTYPE);
 198         }
 199         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 200             shdr == NULL)
 201                 return (EINVAL);
 202
 203         lf = linker_make_file(filename, &link_elf_class);
 204         if (lf == NULL)
 205                 return (ENOMEM);
 206
 207         ef = (elf_file_t)lf;
 208         ef->preloaded = 1;
 209         ef->address = *(caddr_t *)baseptr;
 210         lf->address = *(caddr_t *)baseptr;
 211         lf->size = *(size_t *)sizeptr;
 212
 213         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 214             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 215             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 216             hdr->e_version != EV_CURRENT ||
 217             hdr->e_type != ET_REL ||
 218             hdr->e_machine != ELF_TARG_MACH) {
 219                 error = EFTYPE;
 220                 goto out;
 221         }
 222         ef->e_shdr = shdr;
 223
 224         /* Scan the section header for information and table sizing. */
 225         symtabindex = -1;
 226         symstrindex = -1;
 227         for (i = 0; i < hdr->e_shnum; i++) {
 228                 switch (shdr[i].sh_type) {
 229                 case SHT_PROGBITS:
 230                 case SHT_NOBITS:
 231                         ef->nprogtab++;
 232                         break;
 233                 case SHT_SYMTAB:
 234                         symtabindex = i;
 235                         symstrindex = shdr[i].sh_link;
 236                         break;
 237                 case SHT_REL:
 238                         ef->nrel++;
 239                         break;
 240                 case SHT_RELA:
 241                         ef->nrela++;
 242                         break;
 243                 }
 244         }
 245
 246         shstrindex = hdr->e_shstrndx;
 247         if (ef->nprogtab == 0 || symstrindex < 0 ||
 248             symstrindex >= hdr->e_shnum ||
 249             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 250             shstrindex >= hdr->e_shnum ||
 251             shdr[shstrindex].sh_type != SHT_STRTAB) {
 252                 printf("%s: bad/missing section headers\n", filename);
 253                 error = ENOEXEC;
 254                 goto out;
 255         }
 256
 257         /* Allocate space for tracking the load chunks */
 258         if (ef->nprogtab != 0)
 259                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 260                     M_LINKER, M_WAITOK | M_ZERO);
 261         if (ef->nrel != 0)
 262                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
 263                     M_WAITOK | M_ZERO);
 264         if (ef->nrela != 0)
 265                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
 266                     M_WAITOK | M_ZERO);
 267         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 268             (ef->nrel != 0 && ef->reltab == NULL) ||
 269             (ef->nrela != 0 && ef->relatab == NULL)) {
 270                 error = ENOMEM;
 271                 goto out;
 272         }
 273
 274         /* XXX, relocate the sh_addr fields saved by the loader. */
 275         off = 0;
 276         for (i = 0; i < hdr->e_shnum; i++) {
 277                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 278                         off = shdr[i].sh_addr;
 279         }
 280         for (i = 0; i < hdr->e_shnum; i++) {
 281                 if (shdr[i].sh_addr != 0)
 282                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 283                             (Elf_Addr)ef->address;
 284         }
 285
 286         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 287         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 288         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 289         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 290         ef->shstrcnt = shdr[shstrindex].sh_size;
 291         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 292
 293         /* Now fill out progtab and the relocation tables. */
 294         pb = 0;
 295         rl = 0;
 296         ra = 0;
 297         for (i = 0; i < hdr->e_shnum; i++) {
 298                 switch (shdr[i].sh_type) {
 299                 case SHT_PROGBITS:
 300                 case SHT_NOBITS:
 301                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 302                         if (shdr[i].sh_type == SHT_PROGBITS)
 303                                 ef->progtab[pb].name = "<<PROGBITS>>";
 304                         else
 305                                 ef->progtab[pb].name = "<<NOBITS>>";
 306                         ef->progtab[pb].size = shdr[i].sh_size;
 307                         ef->progtab[pb].sec = i;
 308                         if (ef->shstrtab && shdr[i].sh_name != 0)
 309                                 ef->progtab[pb].name =
 310                                     ef->shstrtab + shdr[i].sh_name;
 311
 312                         /* Update all symbol values with the offset. */
 313                         for (j = 0; j < ef->ddbsymcnt; j++) {
 314                                 es = &ef->ddbsymtab[j];
 315                                 if (es->st_shndx != i)
 316                                         continue;
 317                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 318                         }
 319                         pb++;
 320                         break;
 321                 case SHT_REL:
 322                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 323                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 324                         ef->reltab[rl].sec = shdr[i].sh_info;
 325                         rl++;
 326                         break;
 327                 case SHT_RELA:
 328                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 329                         ef->relatab[ra].nrela =
 330                             shdr[i].sh_size / sizeof(Elf_Rela);
 331                         ef->relatab[ra].sec = shdr[i].sh_info;
 332                         ra++;
 333                         break;
 334                 }
 335         }
 336         if (pb != ef->nprogtab)
 337                 panic("lost progbits");
 338         if (rl != ef->nrel)
 339                 panic("lost rel");
 340         if (ra != ef->nrela)
 341                 panic("lost rela");
 342
 343         /* Local intra-module relocations */
 344         link_elf_reloc_local(lf);
 345
 346         *result = lf;
 347         return (0);
 348
 349 out:
 350         /* preload not done this way */
 351         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 352         return (error);
 353 }
 354
 355 static int
 356 link_elf_link_preload_finish(linker_file_t lf)
 357 {
 358         elf_file_t ef;
 359         int error;
 360
 361         ef = (elf_file_t)lf;
 362         error = relocate_file(ef);
 363         if (error)
 364                 return error;
 365
 366         /* Notify MD code that a module is being loaded. */
 367         error = elf_cpu_load_file(lf);
 368         if (error)
 369                 return (error);
 370
 371         return (0);
 372 }
 373
 374 static int
 375 link_elf_load_file(linker_class_t cls, const char *filename,
 376     linker_file_t *result)
 377 {
 378         struct nameidata nd;
 379         struct thread *td = curthread;  /* XXX */
 380         Elf_Ehdr *hdr;
 381         Elf_Shdr *shdr;
 382         Elf_Sym *es;
 383         int nbytes, i, j;
 384         vm_offset_t mapbase;
 385         size_t mapsize;
 386         int error = 0;
 387         int resid, flags;
 388         elf_file_t ef;
 389         linker_file_t lf;
 390         int symtabindex;
 391         int symstrindex;
 392         int shstrindex;
 393         int nsym;
 394         int pb, rl, ra;
 395         int alignmask;
 396
 397         GIANT_REQUIRED;
 398
 399         shdr = NULL;
 400         lf = NULL;
 401         mapsize = 0;
 402         hdr = NULL;
 403
 404         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 405         flags = FREAD;
 406         error = vn_open(&nd, &flags, 0, -1);
 407         if (error)
 408                 return error;
 409         NDFREE(&nd, NDF_ONLY_PNBUF);
 410 #ifdef MAC
 411         error = mac_check_kld_load(td->td_ucred, nd.ni_vp);
 412         if (error) {
 413                 goto out;
 414         }
 415 #endif
 416
 417         /* Read the elf header from the file. */
 418         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 419         if (hdr == NULL) {
 420                 error = ENOMEM;
 421                 goto out;
 422         }
 423         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
 424             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 425             &resid, td);
 426         if (error)
 427                 goto out;
 428         if (resid != 0){
 429                 error = ENOEXEC;
 430                 goto out;
 431         }
 432
 433         if (!IS_ELF(*hdr)) {
 434                 error = ENOEXEC;
 435                 goto out;
 436         }
 437
 438         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 439             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 440                 link_elf_error("Unsupported file layout");
 441                 error = ENOEXEC;
 442                 goto out;
 443         }
 444         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 445             || hdr->e_version != EV_CURRENT) {
 446                 link_elf_error("Unsupported file version");
 447                 error = ENOEXEC;
 448                 goto out;
 449         }
 450         if (hdr->e_type != ET_REL) {
 451                 link_elf_error("Unsupported file type");
 452                 error = ENOEXEC;
 453                 goto out;
 454         }
 455         if (hdr->e_machine != ELF_TARG_MACH) {
 456                 link_elf_error("Unsupported machine");
 457                 error = ENOEXEC;
 458                 goto out;
 459         }
 460
 461         lf = linker_make_file(filename, &link_elf_class);
 462         if (!lf) {
 463                 error = ENOMEM;
 464                 goto out;
 465         }
 466         ef = (elf_file_t) lf;
 467         ef->nprogtab = 0;
 468         ef->e_shdr = 0;
 469         ef->nrel = 0;
 470         ef->nrela = 0;
 471
 472         /* Allocate and read in the section header */
 473         nbytes = hdr->e_shnum * hdr->e_shentsize;
 474         if (nbytes == 0 || hdr->e_shoff == 0 ||
 475             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 476                 error = ENOEXEC;
 477                 goto out;
 478         }
 479         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 480         if (shdr == NULL) {
 481                 error = ENOMEM;
 482                 goto out;
 483         }
 484         ef->e_shdr = shdr;
 485         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
 486             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
 487         if (error)
 488                 goto out;
 489         if (resid) {
 490                 error = ENOEXEC;
 491                 goto out;
 492         }
 493
 494         /* Scan the section header for information and table sizing. */
 495         nsym = 0;
 496         symtabindex = -1;
 497         symstrindex = -1;
 498         for (i = 0; i < hdr->e_shnum; i++) {
 499                 switch (shdr[i].sh_type) {
 500                 case SHT_PROGBITS:
 501                 case SHT_NOBITS:
 502                         ef->nprogtab++;
 503                         break;
 504                 case SHT_SYMTAB:
 505                         nsym++;
 506                         symtabindex = i;
 507                         symstrindex = shdr[i].sh_link;
 508                         break;
 509                 case SHT_REL:
 510                         ef->nrel++;
 511                         break;
 512                 case SHT_RELA:
 513                         ef->nrela++;
 514                         break;
 515                 case SHT_STRTAB:
 516                         break;
 517                 }
 518         }
 519         if (ef->nprogtab == 0) {
 520                 link_elf_error("file has no contents");
 521                 error = ENOEXEC;
 522                 goto out;
 523         }
 524         if (nsym != 1) {
 525                 /* Only allow one symbol table for now */
 526                 link_elf_error("file has no valid symbol table");
 527                 error = ENOEXEC;
 528                 goto out;
 529         }
 530         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 531             shdr[symstrindex].sh_type != SHT_STRTAB) {
 532                 link_elf_error("file has invalid symbol strings");
 533                 error = ENOEXEC;
 534                 goto out;
 535         }
 536
 537         /* Allocate space for tracking the load chunks */
 538         if (ef->nprogtab != 0)
 539                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 540                     M_LINKER, M_WAITOK | M_ZERO);
 541         if (ef->nrel != 0)
 542                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
 543                     M_WAITOK | M_ZERO);
 544         if (ef->nrela != 0)
 545                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
 546                     M_WAITOK | M_ZERO);
 547         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 548             (ef->nrel != 0 && ef->reltab == NULL) ||
 549             (ef->nrela != 0 && ef->relatab == NULL)) {
 550                 error = ENOMEM;
 551                 goto out;
 552         }
 553
 554         if (symtabindex == -1)
 555                 panic("lost symbol table index");
 556         /* Allocate space for and load the symbol table */
 557         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 558         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 559         if (ef->ddbsymtab == NULL) {
 560                 error = ENOMEM;
 561                 goto out;
 562         }
 563         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
 564             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 565             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 566             &resid, td);
 567         if (error)
 568                 goto out;
 569         if (resid != 0){
 570                 error = EINVAL;
 571                 goto out;
 572         }
 573
 574         if (symstrindex == -1)
 575                 panic("lost symbol string index");
 576         /* Allocate space for and load the symbol strings */
 577         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 578         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 579         if (ef->ddbstrtab == NULL) {
 580                 error = ENOMEM;
 581                 goto out;
 582         }
 583         error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
 584             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 585             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 586             &resid, td);
 587         if (error)
 588                 goto out;
 589         if (resid != 0){
 590                 error = EINVAL;
 591                 goto out;
 592         }
 593
 594         /* Do we have a string table for the section names?  */
 595         shstrindex = -1;
 596         if (hdr->e_shstrndx != 0 &&
 597             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 598                 shstrindex = hdr->e_shstrndx;
 599                 ef->shstrcnt = shdr[shstrindex].sh_size;
 600                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 601                     M_WAITOK);
 602                 if (ef->shstrtab == NULL) {
 603                         error = ENOMEM;
 604                         goto out;
 605                 }
 606                 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
 607                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 608                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 609                     &resid, td);
 610                 if (error)
 611                         goto out;
 612                 if (resid != 0){
 613                         error = EINVAL;
 614                         goto out;
 615                 }
 616         }
 617
 618         /* Size up code/data(progbits) and bss(nobits). */
 619         alignmask = 0;
 620         for (i = 0; i < hdr->e_shnum; i++) {
 621                 switch (shdr[i].sh_type) {
 622                 case SHT_PROGBITS:
 623                 case SHT_NOBITS:
 624                         alignmask = shdr[i].sh_addralign - 1;
 625                         mapsize += alignmask;
 626                         mapsize &= ~alignmask;
 627                         mapsize += shdr[i].sh_size;
 628                         break;
 629                 }
 630         }
 631
 632         /*
 633          * We know how much space we need for the text/data/bss/etc.
 634          * This stuff needs to be in a single chunk so that profiling etc
 635          * can get the bounds and gdb can associate offsets with modules
 636          */
 637         ef->object = vm_object_allocate(OBJT_DEFAULT,
 638             round_page(mapsize) >> PAGE_SHIFT);
 639         if (ef->object == NULL) {
 640                 error = ENOMEM;
 641                 goto out;
 642         }
 643         vm_object_reference(ef->object);
 644         ef->address = (caddr_t) vm_map_min(kernel_map);
 645         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 646             round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE);
 647         if (error) {
 648                 vm_object_deallocate(ef->object);
 649                 ef->object = 0;
 650                 goto out;
 651         }
 652
 653         /* Wire the pages */
 654         vm_map_wire(kernel_map, mapbase,
 655             mapbase + round_page(mapsize),
 656             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 657
 658         /* Inform the kld system about the situation */
 659         lf->address = ef->address = (caddr_t)mapbase;
 660         lf->size = mapsize;
 661
 662         /*
 663          * Now load code/data(progbits), zero bss(nobits), allocate space for
 664          * and load relocs
 665          */
 666         pb = 0;
 667         rl = 0;
 668         ra = 0;
 669         alignmask = 0;
 670         for (i = 0; i < hdr->e_shnum; i++) {
 671                 switch (shdr[i].sh_type) {
 672                 case SHT_PROGBITS:
 673                 case SHT_NOBITS:
 674                         alignmask = shdr[i].sh_addralign - 1;
 675                         mapbase += alignmask;
 676                         mapbase &= ~alignmask;
 677                         ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
 678                         if (shdr[i].sh_type == SHT_PROGBITS) {
 679                                 ef->progtab[pb].name = "<<PROGBITS>>";
 680                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
 681                                     ef->progtab[pb].addr,
 682                                     shdr[i].sh_size, shdr[i].sh_offset,
 683                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 684                                     NOCRED, &resid, td);
 685                                 if (error)
 686                                         goto out;
 687                                 if (resid != 0){
 688                                         error = EINVAL;
 689                                         goto out;
 690                                 }
 691                         } else {
 692                                 ef->progtab[pb].name = "<<NOBITS>>";
 693                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 694                         }
 695                         ef->progtab[pb].size = shdr[i].sh_size;
 696                         ef->progtab[pb].sec = i;
 697                         if (ef->shstrtab && shdr[i].sh_name != 0)
 698                                 ef->progtab[pb].name =
 699                                     ef->shstrtab + shdr[i].sh_name;
 700
 701                         /* Update all symbol values with the offset. */
 702                         for (j = 0; j < ef->ddbsymcnt; j++) {
 703                                 es = &ef->ddbsymtab[j];
 704                                 if (es->st_shndx != i)
 705                                         continue;
 706                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 707                         }
 708                         mapbase += shdr[i].sh_size;
 709                         pb++;
 710                         break;
 711                 case SHT_REL:
 712                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 713                             M_WAITOK);
 714                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 715                         ef->reltab[rl].sec = shdr[i].sh_info;
 716                         error = vn_rdwr(UIO_READ, nd.ni_vp,
 717                             (void *)ef->reltab[rl].rel,
 718                             shdr[i].sh_size, shdr[i].sh_offset,
 719                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 720                             &resid, td);
 721                         if (error)
 722                                 goto out;
 723                         if (resid != 0){
 724                                 error = EINVAL;
 725                                 goto out;
 726                         }
 727                         rl++;
 728                         break;
 729                 case SHT_RELA:
 730                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 731                             M_WAITOK);
 732                         ef->relatab[ra].nrela =
 733                             shdr[i].sh_size / sizeof(Elf_Rela);
 734                         ef->relatab[ra].sec = shdr[i].sh_info;
 735                         error = vn_rdwr(UIO_READ, nd.ni_vp,
 736                             (void *)ef->relatab[ra].rela,
 737                             shdr[i].sh_size, shdr[i].sh_offset,
 738                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 739                             &resid, td);
 740                         if (error)
 741                                 goto out;
 742                         if (resid != 0){
 743                                 error = EINVAL;
 744                                 goto out;
 745                         }
 746                         ra++;
 747                         break;
 748                 }
 749         }
 750         if (pb != ef->nprogtab)
 751                 panic("lost progbits");
 752         if (rl != ef->nrel)
 753                 panic("lost rel");
 754         if (ra != ef->nrela)
 755                 panic("lost rela");
 756         if (mapbase != (vm_offset_t)ef->address + mapsize)
 757                 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 758                     mapbase, ef->address, mapsize,
 759                     (vm_offset_t)ef->address + mapsize);
 760
 761         /* Local intra-module relocations */
 762         link_elf_reloc_local(lf);
 763
 764         /* Pull in dependencies */
 765         error = linker_load_dependencies(lf);
 766         if (error)
 767                 goto out;
 768
 769         /* External relocations */
 770         error = relocate_file(ef);
 771         if (error)
 772                 goto out;
 773
 774         /* Notify MD code that a module is being loaded. */
 775         error = elf_cpu_load_file(lf);
 776         if (error)
 777                 goto out;
 778
 779         *result = lf;
 780
 781 out:
 782         if (error && lf)
 783                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 784         if (hdr)
 785                 free(hdr, M_LINKER);
 786         VOP_UNLOCK(nd.ni_vp, 0, td);
 787         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
 788
 789         return error;
 790 }
 791
 792 static void
 793 link_elf_unload_file(linker_file_t file)
 794 {
 795         elf_file_t ef = (elf_file_t) file;
 796         int i;
 797
 798         /* Notify MD code that a module is being unloaded. */
 799         elf_cpu_unload_file(file);
 800
 801         if (ef->preloaded) {
 802                 if (ef->reltab)
 803                         free(ef->reltab, M_LINKER);
 804                 if (ef->relatab)
 805                         free(ef->relatab, M_LINKER);
 806                 if (ef->progtab)
 807                         free(ef->progtab, M_LINKER);
 808                 if (file->filename != NULL)
 809                         preload_delete_name(file->filename);
 810                 /* XXX reclaim module memory? */
 811                 return;
 812         }
 813
 814         for (i = 0; i < ef->nrel; i++)
 815                 if (ef->reltab[i].rel)
 816                         free(ef->reltab[i].rel, M_LINKER);
 817         for (i = 0; i < ef->nrela; i++)
 818                 if (ef->relatab[i].rela)
 819                         free(ef->relatab[i].rela, M_LINKER);
 820         if (ef->reltab)
 821                 free(ef->reltab, M_LINKER);
 822         if (ef->relatab)
 823                 free(ef->relatab, M_LINKER);
 824         if (ef->progtab)
 825                 free(ef->progtab, M_LINKER);
 826
 827         if (ef->object) {
 828                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
 829                     (vm_offset_t) ef->address +
 830                     (ef->object->size << PAGE_SHIFT));
 831                 vm_object_deallocate(ef->object);
 832         }
 833         if (ef->e_shdr)
 834                 free(ef->e_shdr, M_LINKER);
 835         if (ef->ddbsymtab)
 836                 free(ef->ddbsymtab, M_LINKER);
 837         if (ef->ddbstrtab)
 838                 free(ef->ddbstrtab, M_LINKER);
 839         if (ef->shstrtab)
 840                 free(ef->shstrtab, M_LINKER);
 841 }
 842
 843 static const char *
 844 symbol_name(elf_file_t ef, Elf_Word r_info)
 845 {
 846         const Elf_Sym *ref;
 847
 848         if (ELF_R_SYM(r_info)) {
 849                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
 850                 return ef->ddbstrtab + ref->st_name;
 851         } else
 852                 return NULL;
 853 }
 854
 855 static Elf_Addr
 856 findbase(elf_file_t ef, int sec)
 857 {
 858         int i;
 859         Elf_Addr base = 0;
 860
 861         for (i = 0; i < ef->nprogtab; i++) {
 862                 if (sec == ef->progtab[i].sec) {
 863                         base = (Elf_Addr)ef->progtab[i].addr;
 864                         break;
 865                 }
 866         }
 867         return base;
 868 }
 869
 870 static int
 871 relocate_file(elf_file_t ef)
 872 {
 873         const Elf_Rel *rellim;
 874         const Elf_Rel *rel;
 875         const Elf_Rela *relalim;
 876         const Elf_Rela *rela;
 877         const char *symname;
 878         const Elf_Sym *sym;
 879         int i;
 880         Elf_Word symidx;
 881         Elf_Addr base;
 882
 883
 884         /* Perform relocations without addend if there are any: */
 885         for (i = 0; i < ef->nrel; i++) {
 886                 rel = ef->reltab[i].rel;
 887                 if (rel == NULL)
 888                         panic("lost a reltab!");
 889                 rellim = rel + ef->reltab[i].nrel;
 890                 base = findbase(ef, ef->reltab[i].sec);
 891                 if (base == 0)
 892                         panic("lost base for reltab");
 893                 for ( ; rel < rellim; rel++) {
 894                         symidx = ELF_R_SYM(rel->r_info);
 895                         if (symidx >= ef->ddbsymcnt)
 896                                 continue;
 897                         sym = ef->ddbsymtab + symidx;
 898                         /* Local relocs are already done */
 899                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 900                                 continue;
 901                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
 902                             elf_obj_lookup)) {
 903                                 symname = symbol_name(ef, rel->r_info);
 904                                 printf("link_elf_obj: symbol %s undefined\n",
 905                                     symname);
 906                                 return ENOENT;
 907                         }
 908                 }
 909         }
 910
 911         /* Perform relocations with addend if there are any: */
 912         for (i = 0; i < ef->nrela; i++) {
 913                 rela = ef->relatab[i].rela;
 914                 if (rela == NULL)
 915                         panic("lost a relatab!");
 916                 relalim = rela + ef->relatab[i].nrela;
 917                 base = findbase(ef, ef->relatab[i].sec);
 918                 if (base == 0)
 919                         panic("lost base for relatab");
 920                 for ( ; rela < relalim; rela++) {
 921                         symidx = ELF_R_SYM(rela->r_info);
 922                         if (symidx >= ef->ddbsymcnt)
 923                                 continue;
 924                         sym = ef->ddbsymtab + symidx;
 925                         /* Local relocs are already done */
 926                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 927                                 continue;
 928                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
 929                             elf_obj_lookup)) {
 930                                 symname = symbol_name(ef, rela->r_info);
 931                                 printf("link_elf_obj: symbol %s undefined\n",
 932                                     symname);
 933                                 return ENOENT;
 934                         }
 935                 }
 936         }
 937
 938         return 0;
 939 }
 940
 941 static int
 942 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
 943 {
 944         elf_file_t ef = (elf_file_t) lf;
 945         const Elf_Sym *symp;
 946         const char *strp;
 947         int i;
 948
 949         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 950                 strp = ef->ddbstrtab + symp->st_name;
 951                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
 952                         *sym = (c_linker_sym_t) symp;
 953                         return 0;
 954                 }
 955         }
 956         return ENOENT;
 957 }
 958
 959 static int
 960 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
 961     linker_symval_t *symval)
 962 {
 963         elf_file_t ef = (elf_file_t) lf;
 964         const Elf_Sym *es = (const Elf_Sym*) sym;
 965
 966         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 967                 symval->name = ef->ddbstrtab + es->st_name;
 968                 symval->value = (caddr_t)es->st_value;
 969                 symval->size = es->st_size;
 970                 return 0;
 971         }
 972         return ENOENT;
 973 }
 974
 975 static int
 976 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 977     c_linker_sym_t *sym, long *diffp)
 978 {
 979         elf_file_t ef = (elf_file_t) lf;
 980         u_long off = (uintptr_t) (void *) value;
 981         u_long diff = off;
 982         u_long st_value;
 983         const Elf_Sym *es;
 984         const Elf_Sym *best = 0;
 985         int i;
 986
 987         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 988                 if (es->st_name == 0)
 989                         continue;
 990                 st_value = es->st_value;
 991                 if (off >= st_value) {
 992                         if (off - st_value < diff) {
 993                                 diff = off - st_value;
 994                                 best = es;
 995                                 if (diff == 0)
 996                                         break;
 997                         } else if (off - st_value == diff) {
 998                                 best = es;
 999                         }
1000                 }
1001         }
1002         if (best == 0)
1003                 *diffp = off;
1004         else
1005                 *diffp = diff;
1006         *sym = (c_linker_sym_t) best;
1007
1008         return 0;
1009 }
1010
1011 /*
1012  * Look up a linker set on an ELF system.
1013  */
1014 static int
1015 link_elf_lookup_set(linker_file_t lf, const char *name,
1016     void ***startp, void ***stopp, int *countp)
1017 {
1018         elf_file_t ef = (elf_file_t)lf;
1019         void **start, **stop;
1020         int i, count;
1021
1022         /* Relative to section number */
1023         for (i = 0; i < ef->nprogtab; i++) {
1024                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1025                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1026                         start  = (void **)ef->progtab[i].addr;
1027                         stop = (void **)((char *)ef->progtab[i].addr +
1028                             ef->progtab[i].size);
1029                         count = stop - start;
1030                         if (startp)
1031                                 *startp = start;
1032                         if (stopp)
1033                                 *stopp = stop;
1034                         if (countp)
1035                                 *countp = count;
1036                         return (0);
1037                 }
1038         }
1039         return (ESRCH);
1040 }
1041
1042 static int
1043 link_elf_each_function_name(linker_file_t file,
1044     int (*callback)(const char *, void *), void *opaque)
1045 {
1046         elf_file_t ef = (elf_file_t)file;
1047         const Elf_Sym *symp;
1048         int i, error;
1049
1050         /* Exhaustive search */
1051         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1052                 if (symp->st_value != 0 &&
1053                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1054                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1055                         if (error)
1056                                 return (error);
1057                 }
1058         }
1059         return (0);
1060 }
1061
1062 /*
1063  * Symbol lookup function that can be used when the symbol index is known (ie
1064  * in relocations). It uses the symbol index instead of doing a fully fledged
1065  * hash table based lookup when such is valid. For example for local symbols.
1066  * This is not only more efficient, it's also more correct. It's not always
1067  * the case that the symbol can be found through the hash table.
1068  */
1069 static Elf_Addr
1070 elf_obj_lookup(linker_file_t lf, Elf_Word symidx, int deps)
1071 {
1072         elf_file_t ef = (elf_file_t)lf;
1073         const Elf_Sym *sym;
1074         const char *symbol;
1075         Elf_Addr ret;
1076
1077         /* Don't even try to lookup the symbol if the index is bogus. */
1078         if (symidx >= ef->ddbsymcnt)
1079                 return (0);
1080
1081         sym = ef->ddbsymtab + symidx;
1082
1083         /* Quick answer if there is a definition included. */
1084         if (sym->st_shndx != SHN_UNDEF)
1085                 return (sym->st_value);
1086
1087         /* If we get here, then it is undefined and needs a lookup. */
1088         switch (ELF_ST_BIND(sym->st_info)) {
1089         case STB_LOCAL:
1090                 /* Local, but undefined? huh? */
1091                 return (0);
1092
1093         case STB_GLOBAL:
1094                 /* Relative to Data or Function name */
1095                 symbol = ef->ddbstrtab + sym->st_name;
1096
1097                 /* Force a lookup failure if the symbol name is bogus. */
1098                 if (*symbol == 0)
1099                         return (0);
1100                 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1101                 return ret;
1102
1103         case STB_WEAK:
1104                 printf("link_elf_obj: Weak symbols not supported\n");
1105                 return (0);
1106
1107         default:
1108                 return (0);
1109         }
1110 }
1111
1112 static void
1113 link_elf_reloc_local(linker_file_t lf)
1114 {
1115         elf_file_t ef = (elf_file_t)lf;
1116         const Elf_Rel *rellim;
1117         const Elf_Rel *rel;
1118         const Elf_Rela *relalim;
1119         const Elf_Rela *rela;
1120         const Elf_Sym *sym;
1121         Elf_Addr base;
1122         int i;
1123         Elf_Word symidx;
1124
1125         /* Perform relocations without addend if there are any: */
1126         for (i = 0; i < ef->nrel; i++) {
1127                 rel = ef->reltab[i].rel;
1128                 if (rel == NULL)
1129                         panic("lost a reltab!");
1130                 rellim = rel + ef->reltab[i].nrel;
1131                 base = findbase(ef, ef->reltab[i].sec);
1132                 if (base == 0)
1133                         panic("lost base for reltab");
1134                 for ( ; rel < rellim; rel++) {
1135                         symidx = ELF_R_SYM(rel->r_info);
1136                         if (symidx >= ef->ddbsymcnt)
1137                                 continue;
1138                         sym = ef->ddbsymtab + symidx;
1139                         /* Only do local relocs */
1140                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1141                                 continue;
1142                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1143                             elf_obj_lookup);
1144                 }
1145         }
1146
1147         /* Perform relocations with addend if there are any: */
1148         for (i = 0; i < ef->nrela; i++) {
1149                 rela = ef->relatab[i].rela;
1150                 if (rela == NULL)
1151                         panic("lost a relatab!");
1152                 relalim = rela + ef->relatab[i].nrela;
1153                 base = findbase(ef, ef->relatab[i].sec);
1154                 if (base == 0)
1155                         panic("lost base for relatab");
1156                 for ( ; rela < relalim; rela++) {
1157                         symidx = ELF_R_SYM(rela->r_info);
1158                         if (symidx >= ef->ddbsymcnt)
1159                                 continue;
1160                         sym = ef->ddbsymtab + symidx;
1161                         /* Only do local relocs */
1162                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1163                                 continue;
1164                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1165                             elf_obj_lookup);
1166                 }
1167         }
1168 }