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/malloc.h>
  39 #include <sys/mutex.h>
  40 #include <sys/mount.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 <security/mac/mac_framework.h>
  50
  51 #include <vm/vm.h>
  52 #include <vm/vm_param.h>
  53 #include <vm/vm_object.h>
  54 #include <vm/vm_kern.h>
  55 #include <vm/vm_extern.h>
  56 #include <vm/pmap.h>
  57 #include <vm/vm_map.h>
  58
  59 #include <sys/link_elf.h>
  60
  61 #include "linker_if.h"
  62
  63 typedef struct {
  64         void            *addr;
  65         Elf_Off         size;
  66         int             flags;
  67         int             sec;    /* Original section */
  68         char            *name;
  69 } Elf_progent;
  70
  71 typedef struct {
  72         Elf_Rel         *rel;
  73         int             nrel;
  74         int             sec;
  75 } Elf_relent;
  76
  77 typedef struct {
  78         Elf_Rela        *rela;
  79         int             nrela;
  80         int             sec;
  81 } Elf_relaent;
  82
  83
  84 typedef struct elf_file {
  85         struct linker_file lf;          /* Common fields */
  86
  87         int             preloaded;
  88         caddr_t         address;        /* Relocation address */
  89         vm_object_t     object;         /* VM object to hold file pages */
  90         Elf_Shdr        *e_shdr;
  91
  92         Elf_progent     *progtab;
  93         int             nprogtab;
  94
  95         Elf_relaent     *relatab;
  96         int             nrela;
  97
  98         Elf_relent      *reltab;
  99         int             nrel;
 100
 101         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 102         long            ddbsymcnt;      /* Number of symbols */
 103         caddr_t         ddbstrtab;      /* String table */
 104         long            ddbstrcnt;      /* number of bytes in string table */
 105
 106         caddr_t         shstrtab;       /* Section name string table */
 107         long            shstrcnt;       /* number of bytes in string table */
 108
 109 } *elf_file_t;
 110
 111 static int      link_elf_link_preload(linker_class_t cls,
 112                     const char *, linker_file_t *);
 113 static int      link_elf_link_preload_finish(linker_file_t);
 114 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 115 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 116                     c_linker_sym_t *);
 117 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 118                     linker_symval_t *);
 119 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 120                     c_linker_sym_t *sym, long *diffp);
 121
 122 static void     link_elf_unload_file(linker_file_t);
 123 static int      link_elf_lookup_set(linker_file_t, const char *,
 124                     void ***, void ***, int *);
 125 static int      link_elf_each_function_name(linker_file_t,
 126                     int (*)(const char *, void *), void *);
 127 static void     link_elf_reloc_local(linker_file_t);
 128
 129 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps);
 130
 131 static kobj_method_t link_elf_methods[] = {
 132         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 133         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 134         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 135         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 136         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 137         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 138         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 139         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 140         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 141         { 0, 0 }
 142 };
 143
 144 static struct linker_class link_elf_class = {
 145 #if ELF_TARG_CLASS == ELFCLASS32
 146         "elf32_obj",
 147 #else
 148         "elf64_obj",
 149 #endif
 150         link_elf_methods, sizeof(struct elf_file)
 151 };
 152
 153 static int      relocate_file(elf_file_t ef);
 154
 155 static void
 156 link_elf_error(const char *s)
 157 {
 158         printf("kldload: %s\n", s);
 159 }
 160
 161 static void
 162 link_elf_init(void *arg)
 163 {
 164
 165         linker_add_class(&link_elf_class);
 166 }
 167
 168 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
 169
 170 static int
 171 link_elf_link_preload(linker_class_t cls, const char *filename,
 172     linker_file_t *result)
 173 {
 174         Elf_Ehdr *hdr;
 175         Elf_Shdr *shdr;
 176         Elf_Sym *es;
 177         void *modptr, *baseptr, *sizeptr;
 178         char *type;
 179         elf_file_t ef;
 180         linker_file_t lf;
 181         Elf_Addr off;
 182         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 183
 184         /* Look to see if we have the file preloaded */
 185         modptr = preload_search_by_name(filename);
 186         if (modptr == NULL)
 187                 return ENOENT;
 188
 189         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 190         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 191         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 192         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 193             MODINFOMD_ELFHDR);
 194         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 195             MODINFOMD_SHDR);
 196         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 197             " obj module") != 0 &&
 198             strcmp(type, "elf obj module") != 0)) {
 199                 return (EFTYPE);
 200         }
 201         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 202             shdr == NULL)
 203                 return (EINVAL);
 204
 205         lf = linker_make_file(filename, &link_elf_class);
 206         if (lf == NULL)
 207                 return (ENOMEM);
 208
 209         ef = (elf_file_t)lf;
 210         ef->preloaded = 1;
 211         ef->address = *(caddr_t *)baseptr;
 212         lf->address = *(caddr_t *)baseptr;
 213         lf->size = *(size_t *)sizeptr;
 214
 215         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 216             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 217             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 218             hdr->e_version != EV_CURRENT ||
 219             hdr->e_type != ET_REL ||
 220             hdr->e_machine != ELF_TARG_MACH) {
 221                 error = EFTYPE;
 222                 goto out;
 223         }
 224         ef->e_shdr = shdr;
 225
 226         /* Scan the section header for information and table sizing. */
 227         symtabindex = -1;
 228         symstrindex = -1;
 229         for (i = 0; i < hdr->e_shnum; i++) {
 230                 switch (shdr[i].sh_type) {
 231                 case SHT_PROGBITS:
 232                 case SHT_NOBITS:
 233                         ef->nprogtab++;
 234                         break;
 235                 case SHT_SYMTAB:
 236                         symtabindex = i;
 237                         symstrindex = shdr[i].sh_link;
 238                         break;
 239                 case SHT_REL:
 240                         ef->nrel++;
 241                         break;
 242                 case SHT_RELA:
 243                         ef->nrela++;
 244                         break;
 245                 }
 246         }
 247
 248         shstrindex = hdr->e_shstrndx;
 249         if (ef->nprogtab == 0 || symstrindex < 0 ||
 250             symstrindex >= hdr->e_shnum ||
 251             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 252             shstrindex >= hdr->e_shnum ||
 253             shdr[shstrindex].sh_type != SHT_STRTAB) {
 254                 printf("%s: bad/missing section headers\n", filename);
 255                 error = ENOEXEC;
 256                 goto out;
 257         }
 258
 259         /* Allocate space for tracking the load chunks */
 260         if (ef->nprogtab != 0)
 261                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 262                     M_LINKER, M_WAITOK | M_ZERO);
 263         if (ef->nrel != 0)
 264                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
 265                     M_WAITOK | M_ZERO);
 266         if (ef->nrela != 0)
 267                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
 268                     M_WAITOK | M_ZERO);
 269         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 270             (ef->nrel != 0 && ef->reltab == NULL) ||
 271             (ef->nrela != 0 && ef->relatab == NULL)) {
 272                 error = ENOMEM;
 273                 goto out;
 274         }
 275
 276         /* XXX, relocate the sh_addr fields saved by the loader. */
 277         off = 0;
 278         for (i = 0; i < hdr->e_shnum; i++) {
 279                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 280                         off = shdr[i].sh_addr;
 281         }
 282         for (i = 0; i < hdr->e_shnum; i++) {
 283                 if (shdr[i].sh_addr != 0)
 284                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 285                             (Elf_Addr)ef->address;
 286         }
 287
 288         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 289         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 290         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 291         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 292         ef->shstrcnt = shdr[shstrindex].sh_size;
 293         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 294
 295         /* Now fill out progtab and the relocation tables. */
 296         pb = 0;
 297         rl = 0;
 298         ra = 0;
 299         for (i = 0; i < hdr->e_shnum; i++) {
 300                 switch (shdr[i].sh_type) {
 301                 case SHT_PROGBITS:
 302                 case SHT_NOBITS:
 303                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 304                         if (shdr[i].sh_type == SHT_PROGBITS)
 305                                 ef->progtab[pb].name = "<<PROGBITS>>";
 306                         else
 307                                 ef->progtab[pb].name = "<<NOBITS>>";
 308                         ef->progtab[pb].size = shdr[i].sh_size;
 309                         ef->progtab[pb].sec = i;
 310                         if (ef->shstrtab && shdr[i].sh_name != 0)
 311                                 ef->progtab[pb].name =
 312                                     ef->shstrtab + shdr[i].sh_name;
 313
 314                         /* Update all symbol values with the offset. */
 315                         for (j = 0; j < ef->ddbsymcnt; j++) {
 316                                 es = &ef->ddbsymtab[j];
 317                                 if (es->st_shndx != i)
 318                                         continue;
 319                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 320                         }
 321                         pb++;
 322                         break;
 323                 case SHT_REL:
 324                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 325                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 326                         ef->reltab[rl].sec = shdr[i].sh_info;
 327                         rl++;
 328                         break;
 329                 case SHT_RELA:
 330                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 331                         ef->relatab[ra].nrela =
 332                             shdr[i].sh_size / sizeof(Elf_Rela);
 333                         ef->relatab[ra].sec = shdr[i].sh_info;
 334                         ra++;
 335                         break;
 336                 }
 337         }
 338         if (pb != ef->nprogtab)
 339                 panic("lost progbits");
 340         if (rl != ef->nrel)
 341                 panic("lost rel");
 342         if (ra != ef->nrela)
 343                 panic("lost rela");
 344
 345         /* Local intra-module relocations */
 346         link_elf_reloc_local(lf);
 347
 348         *result = lf;
 349         return (0);
 350
 351 out:
 352         /* preload not done this way */
 353         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 354         return (error);
 355 }
 356
 357 static int
 358 link_elf_link_preload_finish(linker_file_t lf)
 359 {
 360         elf_file_t ef;
 361         int error;
 362
 363         ef = (elf_file_t)lf;
 364         error = relocate_file(ef);
 365         if (error)
 366                 return error;
 367
 368         /* Notify MD code that a module is being loaded. */
 369         error = elf_cpu_load_file(lf);
 370         if (error)
 371                 return (error);
 372
 373         return (0);
 374 }
 375
 376 static int
 377 link_elf_load_file(linker_class_t cls, const char *filename,
 378     linker_file_t *result)
 379 {
 380         struct nameidata nd;
 381         struct thread *td = curthread;  /* XXX */
 382         Elf_Ehdr *hdr;
 383         Elf_Shdr *shdr;
 384         Elf_Sym *es;
 385         int nbytes, i, j;
 386         vm_offset_t mapbase;
 387         size_t mapsize;
 388         int error = 0;
 389         int resid, flags;
 390         elf_file_t ef;
 391         linker_file_t lf;
 392         int symtabindex;
 393         int symstrindex;
 394         int shstrindex;
 395         int nsym;
 396         int pb, rl, ra;
 397         int alignmask;
 398         int vfslocked;
 399
 400         shdr = NULL;
 401         lf = NULL;
 402         mapsize = 0;
 403         hdr = NULL;
 404
 405         NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
 406         flags = FREAD;
 407         error = vn_open(&nd, &flags, 0, -1);
 408         if (error)
 409                 return error;
 410         vfslocked = NDHASGIANT(&nd);
 411         NDFREE(&nd, NDF_ONLY_PNBUF);
 412 #ifdef MAC
 413         error = mac_check_kld_load(td->td_ucred, nd.ni_vp);
 414         if (error) {
 415                 goto out;
 416         }
 417 #endif
 418
 419         /* Read the elf header from the file. */
 420         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 421         if (hdr == NULL) {
 422                 error = ENOMEM;
 423                 goto out;
 424         }
 425         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
 426             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 427             &resid, td);
 428         if (error)
 429                 goto out;
 430         if (resid != 0){
 431                 error = ENOEXEC;
 432                 goto out;
 433         }
 434
 435         if (!IS_ELF(*hdr)) {
 436                 error = ENOEXEC;
 437                 goto out;
 438         }
 439
 440         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 441             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 442                 link_elf_error("Unsupported file layout");
 443                 error = ENOEXEC;
 444                 goto out;
 445         }
 446         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 447             || hdr->e_version != EV_CURRENT) {
 448                 link_elf_error("Unsupported file version");
 449                 error = ENOEXEC;
 450                 goto out;
 451         }
 452         if (hdr->e_type != ET_REL) {
 453                 link_elf_error("Unsupported file type");
 454                 error = ENOEXEC;
 455                 goto out;
 456         }
 457         if (hdr->e_machine != ELF_TARG_MACH) {
 458                 link_elf_error("Unsupported machine");
 459                 error = ENOEXEC;
 460                 goto out;
 461         }
 462
 463         lf = linker_make_file(filename, &link_elf_class);
 464         if (!lf) {
 465                 error = ENOMEM;
 466                 goto out;
 467         }
 468         ef = (elf_file_t) lf;
 469         ef->nprogtab = 0;
 470         ef->e_shdr = 0;
 471         ef->nrel = 0;
 472         ef->nrela = 0;
 473
 474         /* Allocate and read in the section header */
 475         nbytes = hdr->e_shnum * hdr->e_shentsize;
 476         if (nbytes == 0 || hdr->e_shoff == 0 ||
 477             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 478                 error = ENOEXEC;
 479                 goto out;
 480         }
 481         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 482         if (shdr == NULL) {
 483                 error = ENOMEM;
 484                 goto out;
 485         }
 486         ef->e_shdr = shdr;
 487         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
 488             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
 489         if (error)
 490                 goto out;
 491         if (resid) {
 492                 error = ENOEXEC;
 493                 goto out;
 494         }
 495
 496         /* Scan the section header for information and table sizing. */
 497         nsym = 0;
 498         symtabindex = -1;
 499         symstrindex = -1;
 500         for (i = 0; i < hdr->e_shnum; i++) {
 501                 switch (shdr[i].sh_type) {
 502                 case SHT_PROGBITS:
 503                 case SHT_NOBITS:
 504                         ef->nprogtab++;
 505                         break;
 506                 case SHT_SYMTAB:
 507                         nsym++;
 508                         symtabindex = i;
 509                         symstrindex = shdr[i].sh_link;
 510                         break;
 511                 case SHT_REL:
 512                         ef->nrel++;
 513                         break;
 514                 case SHT_RELA:
 515                         ef->nrela++;
 516                         break;
 517                 case SHT_STRTAB:
 518                         break;
 519                 }
 520         }
 521         if (ef->nprogtab == 0) {
 522                 link_elf_error("file has no contents");
 523                 error = ENOEXEC;
 524                 goto out;
 525         }
 526         if (nsym != 1) {
 527                 /* Only allow one symbol table for now */
 528                 link_elf_error("file has no valid symbol table");
 529                 error = ENOEXEC;
 530                 goto out;
 531         }
 532         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 533             shdr[symstrindex].sh_type != SHT_STRTAB) {
 534                 link_elf_error("file has invalid symbol strings");
 535                 error = ENOEXEC;
 536                 goto out;
 537         }
 538
 539         /* Allocate space for tracking the load chunks */
 540         if (ef->nprogtab != 0)
 541                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 542                     M_LINKER, M_WAITOK | M_ZERO);
 543         if (ef->nrel != 0)
 544                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
 545                     M_WAITOK | M_ZERO);
 546         if (ef->nrela != 0)
 547                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
 548                     M_WAITOK | M_ZERO);
 549         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 550             (ef->nrel != 0 && ef->reltab == NULL) ||
 551             (ef->nrela != 0 && ef->relatab == NULL)) {
 552                 error = ENOMEM;
 553                 goto out;
 554         }
 555
 556         if (symtabindex == -1)
 557                 panic("lost symbol table index");
 558         /* Allocate space for and load the symbol table */
 559         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 560         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 561         if (ef->ddbsymtab == NULL) {
 562                 error = ENOMEM;
 563                 goto out;
 564         }
 565         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
 566             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 567             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 568             &resid, td);
 569         if (error)
 570                 goto out;
 571         if (resid != 0){
 572                 error = EINVAL;
 573                 goto out;
 574         }
 575
 576         if (symstrindex == -1)
 577                 panic("lost symbol string index");
 578         /* Allocate space for and load the symbol strings */
 579         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 580         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 581         if (ef->ddbstrtab == NULL) {
 582                 error = ENOMEM;
 583                 goto out;
 584         }
 585         error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
 586             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 587             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 588             &resid, td);
 589         if (error)
 590                 goto out;
 591         if (resid != 0){
 592                 error = EINVAL;
 593                 goto out;
 594         }
 595
 596         /* Do we have a string table for the section names?  */
 597         shstrindex = -1;
 598         if (hdr->e_shstrndx != 0 &&
 599             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 600                 shstrindex = hdr->e_shstrndx;
 601                 ef->shstrcnt = shdr[shstrindex].sh_size;
 602                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 603                     M_WAITOK);
 604                 if (ef->shstrtab == NULL) {
 605                         error = ENOMEM;
 606                         goto out;
 607                 }
 608                 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
 609                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 610                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 611                     &resid, td);
 612                 if (error)
 613                         goto out;
 614                 if (resid != 0){
 615                         error = EINVAL;
 616                         goto out;
 617                 }
 618         }
 619
 620         /* Size up code/data(progbits) and bss(nobits). */
 621         alignmask = 0;
 622         for (i = 0; i < hdr->e_shnum; i++) {
 623                 switch (shdr[i].sh_type) {
 624                 case SHT_PROGBITS:
 625                 case SHT_NOBITS:
 626                         alignmask = shdr[i].sh_addralign - 1;
 627                         mapsize += alignmask;
 628                         mapsize &= ~alignmask;
 629                         mapsize += shdr[i].sh_size;
 630                         break;
 631                 }
 632         }
 633
 634         /*
 635          * We know how much space we need for the text/data/bss/etc.
 636          * This stuff needs to be in a single chunk so that profiling etc
 637          * can get the bounds and gdb can associate offsets with modules
 638          */
 639         ef->object = vm_object_allocate(OBJT_DEFAULT,
 640             round_page(mapsize) >> PAGE_SHIFT);
 641         if (ef->object == NULL) {
 642                 error = ENOMEM;
 643                 goto out;
 644         }
 645         ef->address = (caddr_t) vm_map_min(kernel_map);
 646         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 647             round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE);
 648         if (error) {
 649                 vm_object_deallocate(ef->object);
 650                 ef->object = 0;
 651                 goto out;
 652         }
 653
 654         /* Wire the pages */
 655         error = vm_map_wire(kernel_map, mapbase,
 656             mapbase + round_page(mapsize),
 657             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 658         if (error != KERN_SUCCESS) {
 659                 error = ENOMEM;
 660                 goto out;
 661         }
 662
 663         /* Inform the kld system about the situation */
 664         lf->address = ef->address = (caddr_t)mapbase;
 665         lf->size = mapsize;
 666
 667         /*
 668          * Now load code/data(progbits), zero bss(nobits), allocate space for
 669          * and load relocs
 670          */
 671         pb = 0;
 672         rl = 0;
 673         ra = 0;
 674         alignmask = 0;
 675         for (i = 0; i < hdr->e_shnum; i++) {
 676                 switch (shdr[i].sh_type) {
 677                 case SHT_PROGBITS:
 678                 case SHT_NOBITS:
 679                         alignmask = shdr[i].sh_addralign - 1;
 680                         mapbase += alignmask;
 681                         mapbase &= ~alignmask;
 682                         ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
 683                         if (shdr[i].sh_type == SHT_PROGBITS) {
 684                                 ef->progtab[pb].name = "<<PROGBITS>>";
 685                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
 686                                     ef->progtab[pb].addr,
 687                                     shdr[i].sh_size, shdr[i].sh_offset,
 688                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 689                                     NOCRED, &resid, td);
 690                                 if (error)
 691                                         goto out;
 692                                 if (resid != 0){
 693                                         error = EINVAL;
 694                                         goto out;
 695                                 }
 696                         } else {
 697                                 ef->progtab[pb].name = "<<NOBITS>>";
 698                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 699                         }
 700                         ef->progtab[pb].size = shdr[i].sh_size;
 701                         ef->progtab[pb].sec = i;
 702                         if (ef->shstrtab && shdr[i].sh_name != 0)
 703                                 ef->progtab[pb].name =
 704                                     ef->shstrtab + shdr[i].sh_name;
 705
 706                         /* Update all symbol values with the offset. */
 707                         for (j = 0; j < ef->ddbsymcnt; j++) {
 708                                 es = &ef->ddbsymtab[j];
 709                                 if (es->st_shndx != i)
 710                                         continue;
 711                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 712                         }
 713                         mapbase += shdr[i].sh_size;
 714                         pb++;
 715                         break;
 716                 case SHT_REL:
 717                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 718                             M_WAITOK);
 719                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 720                         ef->reltab[rl].sec = shdr[i].sh_info;
 721                         error = vn_rdwr(UIO_READ, nd.ni_vp,
 722                             (void *)ef->reltab[rl].rel,
 723                             shdr[i].sh_size, shdr[i].sh_offset,
 724                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 725                             &resid, td);
 726                         if (error)
 727                                 goto out;
 728                         if (resid != 0){
 729                                 error = EINVAL;
 730                                 goto out;
 731                         }
 732                         rl++;
 733                         break;
 734                 case SHT_RELA:
 735                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 736                             M_WAITOK);
 737                         ef->relatab[ra].nrela =
 738                             shdr[i].sh_size / sizeof(Elf_Rela);
 739                         ef->relatab[ra].sec = shdr[i].sh_info;
 740                         error = vn_rdwr(UIO_READ, nd.ni_vp,
 741                             (void *)ef->relatab[ra].rela,
 742                             shdr[i].sh_size, shdr[i].sh_offset,
 743                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 744                             &resid, td);
 745                         if (error)
 746                                 goto out;
 747                         if (resid != 0){
 748                                 error = EINVAL;
 749                                 goto out;
 750                         }
 751                         ra++;
 752                         break;
 753                 }
 754         }
 755         if (pb != ef->nprogtab)
 756                 panic("lost progbits");
 757         if (rl != ef->nrel)
 758                 panic("lost rel");
 759         if (ra != ef->nrela)
 760                 panic("lost rela");
 761         if (mapbase != (vm_offset_t)ef->address + mapsize)
 762                 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 763                     mapbase, ef->address, mapsize,
 764                     (vm_offset_t)ef->address + mapsize);
 765
 766         /* Local intra-module relocations */
 767         link_elf_reloc_local(lf);
 768
 769         /* Pull in dependencies */
 770         error = linker_load_dependencies(lf);
 771         if (error)
 772                 goto out;
 773
 774         /* External relocations */
 775         error = relocate_file(ef);
 776         if (error)
 777                 goto out;
 778
 779         /* Notify MD code that a module is being loaded. */
 780         error = elf_cpu_load_file(lf);
 781         if (error)
 782                 goto out;
 783
 784         *result = lf;
 785
 786 out:
 787         if (error && lf)
 788                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 789         if (hdr)
 790                 free(hdr, M_LINKER);
 791         VOP_UNLOCK(nd.ni_vp, 0, td);
 792         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
 793         VFS_UNLOCK_GIANT(vfslocked);
 794
 795         return error;
 796 }
 797
 798 static void
 799 link_elf_unload_file(linker_file_t file)
 800 {
 801         elf_file_t ef = (elf_file_t) file;
 802         int i;
 803
 804         /* Notify MD code that a module is being unloaded. */
 805         elf_cpu_unload_file(file);
 806
 807         if (ef->preloaded) {
 808                 if (ef->reltab)
 809                         free(ef->reltab, M_LINKER);
 810                 if (ef->relatab)
 811                         free(ef->relatab, M_LINKER);
 812                 if (ef->progtab)
 813                         free(ef->progtab, M_LINKER);
 814                 if (file->filename != NULL)
 815                         preload_delete_name(file->filename);
 816                 /* XXX reclaim module memory? */
 817                 return;
 818         }
 819
 820         for (i = 0; i < ef->nrel; i++)
 821                 if (ef->reltab[i].rel)
 822                         free(ef->reltab[i].rel, M_LINKER);
 823         for (i = 0; i < ef->nrela; i++)
 824                 if (ef->relatab[i].rela)
 825                         free(ef->relatab[i].rela, M_LINKER);
 826         if (ef->reltab)
 827                 free(ef->reltab, M_LINKER);
 828         if (ef->relatab)
 829                 free(ef->relatab, M_LINKER);
 830         if (ef->progtab)
 831                 free(ef->progtab, M_LINKER);
 832
 833         if (ef->object) {
 834                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
 835                     (vm_offset_t) ef->address +
 836                     (ef->object->size << PAGE_SHIFT));
 837         }
 838         if (ef->e_shdr)
 839                 free(ef->e_shdr, M_LINKER);
 840         if (ef->ddbsymtab)
 841                 free(ef->ddbsymtab, M_LINKER);
 842         if (ef->ddbstrtab)
 843                 free(ef->ddbstrtab, M_LINKER);
 844         if (ef->shstrtab)
 845                 free(ef->shstrtab, M_LINKER);
 846 }
 847
 848 static const char *
 849 symbol_name(elf_file_t ef, Elf_Size r_info)
 850 {
 851         const Elf_Sym *ref;
 852
 853         if (ELF_R_SYM(r_info)) {
 854                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
 855                 return ef->ddbstrtab + ref->st_name;
 856         } else
 857                 return NULL;
 858 }
 859
 860 static Elf_Addr
 861 findbase(elf_file_t ef, int sec)
 862 {
 863         int i;
 864         Elf_Addr base = 0;
 865
 866         for (i = 0; i < ef->nprogtab; i++) {
 867                 if (sec == ef->progtab[i].sec) {
 868                         base = (Elf_Addr)ef->progtab[i].addr;
 869                         break;
 870                 }
 871         }
 872         return base;
 873 }
 874
 875 static int
 876 relocate_file(elf_file_t ef)
 877 {
 878         const Elf_Rel *rellim;
 879         const Elf_Rel *rel;
 880         const Elf_Rela *relalim;
 881         const Elf_Rela *rela;
 882         const char *symname;
 883         const Elf_Sym *sym;
 884         int i;
 885         Elf_Size symidx;
 886         Elf_Addr base;
 887
 888
 889         /* Perform relocations without addend if there are any: */
 890         for (i = 0; i < ef->nrel; i++) {
 891                 rel = ef->reltab[i].rel;
 892                 if (rel == NULL)
 893                         panic("lost a reltab!");
 894                 rellim = rel + ef->reltab[i].nrel;
 895                 base = findbase(ef, ef->reltab[i].sec);
 896                 if (base == 0)
 897                         panic("lost base for reltab");
 898                 for ( ; rel < rellim; rel++) {
 899                         symidx = ELF_R_SYM(rel->r_info);
 900                         if (symidx >= ef->ddbsymcnt)
 901                                 continue;
 902                         sym = ef->ddbsymtab + symidx;
 903                         /* Local relocs are already done */
 904                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 905                                 continue;
 906                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
 907                             elf_obj_lookup)) {
 908                                 symname = symbol_name(ef, rel->r_info);
 909                                 printf("link_elf_obj: symbol %s undefined\n",
 910                                     symname);
 911                                 return ENOENT;
 912                         }
 913                 }
 914         }
 915
 916         /* Perform relocations with addend if there are any: */
 917         for (i = 0; i < ef->nrela; i++) {
 918                 rela = ef->relatab[i].rela;
 919                 if (rela == NULL)
 920                         panic("lost a relatab!");
 921                 relalim = rela + ef->relatab[i].nrela;
 922                 base = findbase(ef, ef->relatab[i].sec);
 923                 if (base == 0)
 924                         panic("lost base for relatab");
 925                 for ( ; rela < relalim; rela++) {
 926                         symidx = ELF_R_SYM(rela->r_info);
 927                         if (symidx >= ef->ddbsymcnt)
 928                                 continue;
 929                         sym = ef->ddbsymtab + symidx;
 930                         /* Local relocs are already done */
 931                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 932                                 continue;
 933                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
 934                             elf_obj_lookup)) {
 935                                 symname = symbol_name(ef, rela->r_info);
 936                                 printf("link_elf_obj: symbol %s undefined\n",
 937                                     symname);
 938                                 return ENOENT;
 939                         }
 940                 }
 941         }
 942
 943         return 0;
 944 }
 945
 946 static int
 947 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
 948 {
 949         elf_file_t ef = (elf_file_t) lf;
 950         const Elf_Sym *symp;
 951         const char *strp;
 952         int i;
 953
 954         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 955                 strp = ef->ddbstrtab + symp->st_name;
 956                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
 957                         *sym = (c_linker_sym_t) symp;
 958                         return 0;
 959                 }
 960         }
 961         return ENOENT;
 962 }
 963
 964 static int
 965 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
 966     linker_symval_t *symval)
 967 {
 968         elf_file_t ef = (elf_file_t) lf;
 969         const Elf_Sym *es = (const Elf_Sym*) sym;
 970
 971         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 972                 symval->name = ef->ddbstrtab + es->st_name;
 973                 symval->value = (caddr_t)es->st_value;
 974                 symval->size = es->st_size;
 975                 return 0;
 976         }
 977         return ENOENT;
 978 }
 979
 980 static int
 981 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 982     c_linker_sym_t *sym, long *diffp)
 983 {
 984         elf_file_t ef = (elf_file_t) lf;
 985         u_long off = (uintptr_t) (void *) value;
 986         u_long diff = off;
 987         u_long st_value;
 988         const Elf_Sym *es;
 989         const Elf_Sym *best = 0;
 990         int i;
 991
 992         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 993                 if (es->st_name == 0)
 994                         continue;
 995                 st_value = es->st_value;
 996                 if (off >= st_value) {
 997                         if (off - st_value < diff) {
 998                                 diff = off - st_value;
 999                                 best = es;
1000                                 if (diff == 0)
1001                                         break;
1002                         } else if (off - st_value == diff) {
1003                                 best = es;
1004                         }
1005                 }
1006         }
1007         if (best == 0)
1008                 *diffp = off;
1009         else
1010                 *diffp = diff;
1011         *sym = (c_linker_sym_t) best;
1012
1013         return 0;
1014 }
1015
1016 /*
1017  * Look up a linker set on an ELF system.
1018  */
1019 static int
1020 link_elf_lookup_set(linker_file_t lf, const char *name,
1021     void ***startp, void ***stopp, int *countp)
1022 {
1023         elf_file_t ef = (elf_file_t)lf;
1024         void **start, **stop;
1025         int i, count;
1026
1027         /* Relative to section number */
1028         for (i = 0; i < ef->nprogtab; i++) {
1029                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1030                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1031                         start  = (void **)ef->progtab[i].addr;
1032                         stop = (void **)((char *)ef->progtab[i].addr +
1033                             ef->progtab[i].size);
1034                         count = stop - start;
1035                         if (startp)
1036                                 *startp = start;
1037                         if (stopp)
1038                                 *stopp = stop;
1039                         if (countp)
1040                                 *countp = count;
1041                         return (0);
1042                 }
1043         }
1044         return (ESRCH);
1045 }
1046
1047 static int
1048 link_elf_each_function_name(linker_file_t file,
1049     int (*callback)(const char *, void *), void *opaque)
1050 {
1051         elf_file_t ef = (elf_file_t)file;
1052         const Elf_Sym *symp;
1053         int i, error;
1054
1055         /* Exhaustive search */
1056         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1057                 if (symp->st_value != 0 &&
1058                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1059                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1060                         if (error)
1061                                 return (error);
1062                 }
1063         }
1064         return (0);
1065 }
1066
1067 /*
1068  * Symbol lookup function that can be used when the symbol index is known (ie
1069  * in relocations). It uses the symbol index instead of doing a fully fledged
1070  * hash table based lookup when such is valid. For example for local symbols.
1071  * This is not only more efficient, it's also more correct. It's not always
1072  * the case that the symbol can be found through the hash table.
1073  */
1074 static Elf_Addr
1075 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1076 {
1077         elf_file_t ef = (elf_file_t)lf;
1078         const Elf_Sym *sym;
1079         const char *symbol;
1080         Elf_Addr ret;
1081
1082         /* Don't even try to lookup the symbol if the index is bogus. */
1083         if (symidx >= ef->ddbsymcnt)
1084                 return (0);
1085
1086         sym = ef->ddbsymtab + symidx;
1087
1088         /* Quick answer if there is a definition included. */
1089         if (sym->st_shndx != SHN_UNDEF)
1090                 return (sym->st_value);
1091
1092         /* If we get here, then it is undefined and needs a lookup. */
1093         switch (ELF_ST_BIND(sym->st_info)) {
1094         case STB_LOCAL:
1095                 /* Local, but undefined? huh? */
1096                 return (0);
1097
1098         case STB_GLOBAL:
1099                 /* Relative to Data or Function name */
1100                 symbol = ef->ddbstrtab + sym->st_name;
1101
1102                 /* Force a lookup failure if the symbol name is bogus. */
1103                 if (*symbol == 0)
1104                         return (0);
1105                 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1106                 return ret;
1107
1108         case STB_WEAK:
1109                 printf("link_elf_obj: Weak symbols not supported\n");
1110                 return (0);
1111
1112         default:
1113                 return (0);
1114         }
1115 }
1116
1117 static void
1118 link_elf_fix_link_set(elf_file_t ef)
1119 {
1120         static const char startn[] = "__start_";
1121         static const char stopn[] = "__stop_";
1122         Elf_Sym *sym;
1123         const char *sym_name, *linkset_name;
1124         Elf_Addr startp, stopp;
1125         Elf_Size symidx;
1126         int start, i;
1127
1128         startp = stopp = 0;
1129         for (symidx = 1 /* zero entry is special */;
1130                 symidx < ef->ddbsymcnt; symidx++) {
1131                 sym = ef->ddbsymtab + symidx;
1132                 if (sym->st_shndx != SHN_UNDEF)
1133                         continue;
1134
1135                 sym_name = ef->ddbstrtab + sym->st_name;
1136                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1137                         start = 1;
1138                         linkset_name = sym_name + sizeof(startn) - 1;
1139                 }
1140                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1141                         start = 0;
1142                         linkset_name = sym_name + sizeof(stopn) - 1;
1143                 }
1144                 else
1145                         continue;
1146
1147                 for (i = 0; i < ef->nprogtab; i++) {
1148                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1149                                 startp = (Elf_Addr)ef->progtab[i].addr;
1150                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1151                                 break;
1152                         }
1153                 }
1154                 if (i == ef->nprogtab)
1155                         continue;
1156
1157                 sym->st_value = start ? startp : stopp;
1158                 sym->st_shndx = i;
1159         }
1160 }
1161
1162 static void
1163 link_elf_reloc_local(linker_file_t lf)
1164 {
1165         elf_file_t ef = (elf_file_t)lf;
1166         const Elf_Rel *rellim;
1167         const Elf_Rel *rel;
1168         const Elf_Rela *relalim;
1169         const Elf_Rela *rela;
1170         const Elf_Sym *sym;
1171         Elf_Addr base;
1172         int i;
1173         Elf_Size symidx;
1174
1175         link_elf_fix_link_set(ef);
1176
1177         /* Perform relocations without addend if there are any: */
1178         for (i = 0; i < ef->nrel; i++) {
1179                 rel = ef->reltab[i].rel;
1180                 if (rel == NULL)
1181                         panic("lost a reltab!");
1182                 rellim = rel + ef->reltab[i].nrel;
1183                 base = findbase(ef, ef->reltab[i].sec);
1184                 if (base == 0)
1185                         panic("lost base for reltab");
1186                 for ( ; rel < rellim; rel++) {
1187                         symidx = ELF_R_SYM(rel->r_info);
1188                         if (symidx >= ef->ddbsymcnt)
1189                                 continue;
1190                         sym = ef->ddbsymtab + symidx;
1191                         /* Only do local relocs */
1192                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1193                                 continue;
1194                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1195                             elf_obj_lookup);
1196                 }
1197         }
1198
1199         /* Perform relocations with addend if there are any: */
1200         for (i = 0; i < ef->nrela; i++) {
1201                 rela = ef->relatab[i].rela;
1202                 if (rela == NULL)
1203                         panic("lost a relatab!");
1204                 relalim = rela + ef->relatab[i].nrela;
1205                 base = findbase(ef, ef->relatab[i].sec);
1206                 if (base == 0)
1207                         panic("lost base for relatab");
1208                 for ( ; rela < relalim; rela++) {
1209                         symidx = ELF_R_SYM(rela->r_info);
1210                         if (symidx >= ef->ddbsymcnt)
1211                                 continue;
1212                         sym = ef->ddbsymtab + symidx;
1213                         /* Only do local relocs */
1214                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1215                                 continue;
1216                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1217                             elf_obj_lookup);
1218                 }
1219         }
1220 }