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/mount.h>
  42 #include <sys/proc.h>
  43 #include <sys/namei.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/vnode.h>
  46 #include <sys/linker.h>
  47
  48 #include <machine/elf.h>
  49
  50 #include <vm/vm.h>
  51 #include <vm/vm_param.h>
  52 #include <vm/vm_object.h>
  53 #include <vm/vm_kern.h>
  54 #include <vm/vm_extern.h>
  55 #include <vm/pmap.h>
  56 #include <vm/vm_map.h>
  57
  58 #include <sys/link_elf.h>
  59
  60 #include "linker_if.h"
  61
  62 typedef struct {
  63         void            *addr;
  64         Elf_Off         size;
  65         int             flags;
  66         int             sec;    /* Original section */
  67         char            *name;
  68 } Elf_progent;
  69
  70 typedef struct {
  71         Elf_Rel         *rel;
  72         int             nrel;
  73         int             sec;
  74 } Elf_relent;
  75
  76 typedef struct {
  77         Elf_Rela        *rela;
  78         int             nrela;
  79         int             sec;
  80 } Elf_relaent;
  81
  82
  83 typedef struct elf_file {
  84         struct linker_file lf;          /* Common fields */
  85
  86         int             preloaded;
  87         caddr_t         address;        /* Relocation address */
  88         vm_object_t     object;         /* VM object to hold file pages */
  89         Elf_Shdr        *e_shdr;
  90
  91         Elf_progent     *progtab;
  92         int             nprogtab;
  93
  94         Elf_relaent     *relatab;
  95         int             nrela;
  96
  97         Elf_relent      *reltab;
  98         int             nrel;
  99
 100         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 101         long            ddbsymcnt;      /* Number of symbols */
 102         caddr_t         ddbstrtab;      /* String table */
 103         long            ddbstrcnt;      /* number of bytes in string table */
 104
 105         caddr_t         shstrtab;       /* Section name string table */
 106         long            shstrcnt;       /* number of bytes in string table */
 107
 108 } *elf_file_t;
 109
 110 static int      link_elf_link_preload(linker_class_t cls,
 111                     const char *, linker_file_t *);
 112 static int      link_elf_link_preload_finish(linker_file_t);
 113 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 114 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 115                     c_linker_sym_t *);
 116 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 117                     linker_symval_t *);
 118 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 119                     c_linker_sym_t *sym, long *diffp);
 120
 121 static void     link_elf_unload_file(linker_file_t);
 122 static int      link_elf_lookup_set(linker_file_t, const char *,
 123                     void ***, void ***, int *);
 124 static int      link_elf_each_function_name(linker_file_t,
 125                     int (*)(const char *, void *), void *);
 126 static void     link_elf_reloc_local(linker_file_t);
 127
 128 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps);
 129
 130 static kobj_method_t link_elf_methods[] = {
 131         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 132         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 133         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 134         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 135         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 136         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 137         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 138         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 139         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 140         { 0, 0 }
 141 };
 142
 143 static struct linker_class link_elf_class = {
 144 #if ELF_TARG_CLASS == ELFCLASS32
 145         "elf32_obj",
 146 #else
 147         "elf64_obj",
 148 #endif
 149         link_elf_methods, sizeof(struct elf_file)
 150 };
 151
 152 static int      relocate_file(elf_file_t ef);
 153
 154 static void
 155 link_elf_error(const char *s)
 156 {
 157         printf("kldload: %s\n", s);
 158 }
 159
 160 static void
 161 link_elf_init(void *arg)
 162 {
 163
 164         linker_add_class(&link_elf_class);
 165 }
 166
 167 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
 168
 169 static int
 170 link_elf_link_preload(linker_class_t cls, const char *filename,
 171     linker_file_t *result)
 172 {
 173         Elf_Ehdr *hdr;
 174         Elf_Shdr *shdr;
 175         Elf_Sym *es;
 176         void *modptr, *baseptr, *sizeptr;
 177         char *type;
 178         elf_file_t ef;
 179         linker_file_t lf;
 180         Elf_Addr off;
 181         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 182
 183         /* Look to see if we have the file preloaded */
 184         modptr = preload_search_by_name(filename);
 185         if (modptr == NULL)
 186                 return ENOENT;
 187
 188         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 189         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 190         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 191         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 192             MODINFOMD_ELFHDR);
 193         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 194             MODINFOMD_SHDR);
 195         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 196             " obj module") != 0 &&
 197             strcmp(type, "elf obj module") != 0)) {
 198                 return (EFTYPE);
 199         }
 200         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 201             shdr == NULL)
 202                 return (EINVAL);
 203
 204         lf = linker_make_file(filename, &link_elf_class);
 205         if (lf == NULL)
 206                 return (ENOMEM);
 207
 208         ef = (elf_file_t)lf;
 209         ef->preloaded = 1;
 210         ef->address = *(caddr_t *)baseptr;
 211         lf->address = *(caddr_t *)baseptr;
 212         lf->size = *(size_t *)sizeptr;
 213
 214         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 215             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 216             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 217             hdr->e_version != EV_CURRENT ||
 218             hdr->e_type != ET_REL ||
 219             hdr->e_machine != ELF_TARG_MACH) {
 220                 error = EFTYPE;
 221                 goto out;
 222         }
 223         ef->e_shdr = shdr;
 224
 225         /* Scan the section header for information and table sizing. */
 226         symtabindex = -1;
 227         symstrindex = -1;
 228         for (i = 0; i < hdr->e_shnum; i++) {
 229                 switch (shdr[i].sh_type) {
 230                 case SHT_PROGBITS:
 231                 case SHT_NOBITS:
 232                         ef->nprogtab++;
 233                         break;
 234                 case SHT_SYMTAB:
 235                         symtabindex = i;
 236                         symstrindex = shdr[i].sh_link;
 237                         break;
 238                 case SHT_REL:
 239                         ef->nrel++;
 240                         break;
 241                 case SHT_RELA:
 242                         ef->nrela++;
 243                         break;
 244                 }
 245         }
 246
 247         shstrindex = hdr->e_shstrndx;
 248         if (ef->nprogtab == 0 || symstrindex < 0 ||
 249             symstrindex >= hdr->e_shnum ||
 250             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 251             shstrindex >= hdr->e_shnum ||
 252             shdr[shstrindex].sh_type != SHT_STRTAB) {
 253                 printf("%s: bad/missing section headers\n", filename);
 254                 error = ENOEXEC;
 255                 goto out;
 256         }
 257
 258         /* Allocate space for tracking the load chunks */
 259         if (ef->nprogtab != 0)
 260                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 261                     M_LINKER, M_WAITOK | M_ZERO);
 262         if (ef->nrel != 0)
 263                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
 264                     M_WAITOK | M_ZERO);
 265         if (ef->nrela != 0)
 266                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
 267                     M_WAITOK | M_ZERO);
 268         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 269             (ef->nrel != 0 && ef->reltab == NULL) ||
 270             (ef->nrela != 0 && ef->relatab == NULL)) {
 271                 error = ENOMEM;
 272                 goto out;
 273         }
 274
 275         /* XXX, relocate the sh_addr fields saved by the loader. */
 276         off = 0;
 277         for (i = 0; i < hdr->e_shnum; i++) {
 278                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 279                         off = shdr[i].sh_addr;
 280         }
 281         for (i = 0; i < hdr->e_shnum; i++) {
 282                 if (shdr[i].sh_addr != 0)
 283                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 284                             (Elf_Addr)ef->address;
 285         }
 286
 287         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 288         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 289         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 290         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 291         ef->shstrcnt = shdr[shstrindex].sh_size;
 292         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 293
 294         /* Now fill out progtab and the relocation tables. */
 295         pb = 0;
 296         rl = 0;
 297         ra = 0;
 298         for (i = 0; i < hdr->e_shnum; i++) {
 299                 switch (shdr[i].sh_type) {
 300                 case SHT_PROGBITS:
 301                 case SHT_NOBITS:
 302                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 303                         if (shdr[i].sh_type == SHT_PROGBITS)
 304                                 ef->progtab[pb].name = "<<PROGBITS>>";
 305                         else
 306                                 ef->progtab[pb].name = "<<NOBITS>>";
 307                         ef->progtab[pb].size = shdr[i].sh_size;
 308                         ef->progtab[pb].sec = i;
 309                         if (ef->shstrtab && shdr[i].sh_name != 0)
 310                                 ef->progtab[pb].name =
 311                                     ef->shstrtab + shdr[i].sh_name;
 312
 313                         /* Update all symbol values with the offset. */
 314                         for (j = 0; j < ef->ddbsymcnt; j++) {
 315                                 es = &ef->ddbsymtab[j];
 316                                 if (es->st_shndx != i)
 317                                         continue;
 318                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 319                         }
 320                         pb++;
 321                         break;
 322                 case SHT_REL:
 323                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 324                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 325                         ef->reltab[rl].sec = shdr[i].sh_info;
 326                         rl++;
 327                         break;
 328                 case SHT_RELA:
 329                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 330                         ef->relatab[ra].nrela =
 331                             shdr[i].sh_size / sizeof(Elf_Rela);
 332                         ef->relatab[ra].sec = shdr[i].sh_info;
 333                         ra++;
 334                         break;
 335                 }
 336         }
 337         if (pb != ef->nprogtab)
 338                 panic("lost progbits");
 339         if (rl != ef->nrel)
 340                 panic("lost rel");
 341         if (ra != ef->nrela)
 342                 panic("lost rela");
 343
 344         /* Local intra-module relocations */
 345         link_elf_reloc_local(lf);
 346
 347         *result = lf;
 348         return (0);
 349
 350 out:
 351         /* preload not done this way */
 352         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 353         return (error);
 354 }
 355
 356 static int
 357 link_elf_link_preload_finish(linker_file_t lf)
 358 {
 359         elf_file_t ef;
 360         int error;
 361
 362         ef = (elf_file_t)lf;
 363         error = relocate_file(ef);
 364         if (error)
 365                 return error;
 366
 367         /* Notify MD code that a module is being loaded. */
 368         error = elf_cpu_load_file(lf);
 369         if (error)
 370                 return (error);
 371
 372         return (0);
 373 }
 374
 375 static int
 376 link_elf_load_file(linker_class_t cls, const char *filename,
 377     linker_file_t *result)
 378 {
 379         struct nameidata nd;
 380         struct thread *td = curthread;  /* XXX */
 381         Elf_Ehdr *hdr;
 382         Elf_Shdr *shdr;
 383         Elf_Sym *es;
 384         int nbytes, i, j;
 385         vm_offset_t mapbase;
 386         size_t mapsize;
 387         int error = 0;
 388         int resid, flags;
 389         elf_file_t ef;
 390         linker_file_t lf;
 391         int symtabindex;
 392         int symstrindex;
 393         int shstrindex;
 394         int nsym;
 395         int pb, rl, ra;
 396         int alignmask;
 397         int vfslocked;
 398
 399         shdr = NULL;
 400         lf = NULL;
 401         mapsize = 0;
 402         hdr = NULL;
 403
 404         NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td);
 405         flags = FREAD;
 406         error = vn_open(&nd, &flags, 0, -1);
 407         if (error)
 408                 return error;
 409         vfslocked = NDHASGIANT(&nd);
 410         NDFREE(&nd, NDF_ONLY_PNBUF);
 411 #ifdef MAC
 412         error = mac_check_kld_load(td->td_ucred, nd.ni_vp);
 413         if (error) {
 414                 goto out;
 415         }
 416 #endif
 417
 418         /* Read the elf header from the file. */
 419         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 420         if (hdr == NULL) {
 421                 error = ENOMEM;
 422                 goto out;
 423         }
 424         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0,
 425             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 426             &resid, td);
 427         if (error)
 428                 goto out;
 429         if (resid != 0){
 430                 error = ENOEXEC;
 431                 goto out;
 432         }
 433
 434         if (!IS_ELF(*hdr)) {
 435                 error = ENOEXEC;
 436                 goto out;
 437         }
 438
 439         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 440             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 441                 link_elf_error("Unsupported file layout");
 442                 error = ENOEXEC;
 443                 goto out;
 444         }
 445         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 446             || hdr->e_version != EV_CURRENT) {
 447                 link_elf_error("Unsupported file version");
 448                 error = ENOEXEC;
 449                 goto out;
 450         }
 451         if (hdr->e_type != ET_REL) {
 452                 link_elf_error("Unsupported file type");
 453                 error = ENOEXEC;
 454                 goto out;
 455         }
 456         if (hdr->e_machine != ELF_TARG_MACH) {
 457                 link_elf_error("Unsupported machine");
 458                 error = ENOEXEC;
 459                 goto out;
 460         }
 461
 462         lf = linker_make_file(filename, &link_elf_class);
 463         if (!lf) {
 464                 error = ENOMEM;
 465                 goto out;
 466         }
 467         ef = (elf_file_t) lf;
 468         ef->nprogtab = 0;
 469         ef->e_shdr = 0;
 470         ef->nrel = 0;
 471         ef->nrela = 0;
 472
 473         /* Allocate and read in the section header */
 474         nbytes = hdr->e_shnum * hdr->e_shentsize;
 475         if (nbytes == 0 || hdr->e_shoff == 0 ||
 476             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 477                 error = ENOEXEC;
 478                 goto out;
 479         }
 480         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 481         if (shdr == NULL) {
 482                 error = ENOMEM;
 483                 goto out;
 484         }
 485         ef->e_shdr = shdr;
 486         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff,
 487             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td);
 488         if (error)
 489                 goto out;
 490         if (resid) {
 491                 error = ENOEXEC;
 492                 goto out;
 493         }
 494
 495         /* Scan the section header for information and table sizing. */
 496         nsym = 0;
 497         symtabindex = -1;
 498         symstrindex = -1;
 499         for (i = 0; i < hdr->e_shnum; i++) {
 500                 switch (shdr[i].sh_type) {
 501                 case SHT_PROGBITS:
 502                 case SHT_NOBITS:
 503                         ef->nprogtab++;
 504                         break;
 505                 case SHT_SYMTAB:
 506                         nsym++;
 507                         symtabindex = i;
 508                         symstrindex = shdr[i].sh_link;
 509                         break;
 510                 case SHT_REL:
 511                         ef->nrel++;
 512                         break;
 513                 case SHT_RELA:
 514                         ef->nrela++;
 515                         break;
 516                 case SHT_STRTAB:
 517                         break;
 518                 }
 519         }
 520         if (ef->nprogtab == 0) {
 521                 link_elf_error("file has no contents");
 522                 error = ENOEXEC;
 523                 goto out;
 524         }
 525         if (nsym != 1) {
 526                 /* Only allow one symbol table for now */
 527                 link_elf_error("file has no valid symbol table");
 528                 error = ENOEXEC;
 529                 goto out;
 530         }
 531         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 532             shdr[symstrindex].sh_type != SHT_STRTAB) {
 533                 link_elf_error("file has invalid symbol strings");
 534                 error = ENOEXEC;
 535                 goto out;
 536         }
 537
 538         /* Allocate space for tracking the load chunks */
 539         if (ef->nprogtab != 0)
 540                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 541                     M_LINKER, M_WAITOK | M_ZERO);
 542         if (ef->nrel != 0)
 543                 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER,
 544                     M_WAITOK | M_ZERO);
 545         if (ef->nrela != 0)
 546                 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER,
 547                     M_WAITOK | M_ZERO);
 548         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 549             (ef->nrel != 0 && ef->reltab == NULL) ||
 550             (ef->nrela != 0 && ef->relatab == NULL)) {
 551                 error = ENOMEM;
 552                 goto out;
 553         }
 554
 555         if (symtabindex == -1)
 556                 panic("lost symbol table index");
 557         /* Allocate space for and load the symbol table */
 558         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 559         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 560         if (ef->ddbsymtab == NULL) {
 561                 error = ENOMEM;
 562                 goto out;
 563         }
 564         error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab,
 565             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 566             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 567             &resid, td);
 568         if (error)
 569                 goto out;
 570         if (resid != 0){
 571                 error = EINVAL;
 572                 goto out;
 573         }
 574
 575         if (symstrindex == -1)
 576                 panic("lost symbol string index");
 577         /* Allocate space for and load the symbol strings */
 578         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 579         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 580         if (ef->ddbstrtab == NULL) {
 581                 error = ENOMEM;
 582                 goto out;
 583         }
 584         error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab,
 585             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 586             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 587             &resid, td);
 588         if (error)
 589                 goto out;
 590         if (resid != 0){
 591                 error = EINVAL;
 592                 goto out;
 593         }
 594
 595         /* Do we have a string table for the section names?  */
 596         shstrindex = -1;
 597         if (hdr->e_shstrndx != 0 &&
 598             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 599                 shstrindex = hdr->e_shstrndx;
 600                 ef->shstrcnt = shdr[shstrindex].sh_size;
 601                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 602                     M_WAITOK);
 603                 if (ef->shstrtab == NULL) {
 604                         error = ENOMEM;
 605                         goto out;
 606                 }
 607                 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab,
 608                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 609                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 610                     &resid, td);
 611                 if (error)
 612                         goto out;
 613                 if (resid != 0){
 614                         error = EINVAL;
 615                         goto out;
 616                 }
 617         }
 618
 619         /* Size up code/data(progbits) and bss(nobits). */
 620         alignmask = 0;
 621         for (i = 0; i < hdr->e_shnum; i++) {
 622                 switch (shdr[i].sh_type) {
 623                 case SHT_PROGBITS:
 624                 case SHT_NOBITS:
 625                         alignmask = shdr[i].sh_addralign - 1;
 626                         mapsize += alignmask;
 627                         mapsize &= ~alignmask;
 628                         mapsize += shdr[i].sh_size;
 629                         break;
 630                 }
 631         }
 632
 633         /*
 634          * We know how much space we need for the text/data/bss/etc.
 635          * This stuff needs to be in a single chunk so that profiling etc
 636          * can get the bounds and gdb can associate offsets with modules
 637          */
 638         ef->object = vm_object_allocate(OBJT_DEFAULT,
 639             round_page(mapsize) >> PAGE_SHIFT);
 640         if (ef->object == NULL) {
 641                 error = ENOMEM;
 642                 goto out;
 643         }
 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         error = vm_map_wire(kernel_map, mapbase,
 655             mapbase + round_page(mapsize),
 656             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 657         if (error != KERN_SUCCESS) {
 658                 error = ENOMEM;
 659                 goto out;
 660         }
 661
 662         /* Inform the kld system about the situation */
 663         lf->address = ef->address = (caddr_t)mapbase;
 664         lf->size = mapsize;
 665
 666         /*
 667          * Now load code/data(progbits), zero bss(nobits), allocate space for
 668          * and load relocs
 669          */
 670         pb = 0;
 671         rl = 0;
 672         ra = 0;
 673         alignmask = 0;
 674         for (i = 0; i < hdr->e_shnum; i++) {
 675                 switch (shdr[i].sh_type) {
 676                 case SHT_PROGBITS:
 677                 case SHT_NOBITS:
 678                         alignmask = shdr[i].sh_addralign - 1;
 679                         mapbase += alignmask;
 680                         mapbase &= ~alignmask;
 681                         ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
 682                         if (shdr[i].sh_type == SHT_PROGBITS) {
 683                                 ef->progtab[pb].name = "<<PROGBITS>>";
 684                                 error = vn_rdwr(UIO_READ, nd.ni_vp,
 685                                     ef->progtab[pb].addr,
 686                                     shdr[i].sh_size, shdr[i].sh_offset,
 687                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 688                                     NOCRED, &resid, td);
 689                                 if (error)
 690                                         goto out;
 691                                 if (resid != 0){
 692                                         error = EINVAL;
 693                                         goto out;
 694                                 }
 695                         } else {
 696                                 ef->progtab[pb].name = "<<NOBITS>>";
 697                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 698                         }
 699                         ef->progtab[pb].size = shdr[i].sh_size;
 700                         ef->progtab[pb].sec = i;
 701                         if (ef->shstrtab && shdr[i].sh_name != 0)
 702                                 ef->progtab[pb].name =
 703                                     ef->shstrtab + shdr[i].sh_name;
 704
 705                         /* Update all symbol values with the offset. */
 706                         for (j = 0; j < ef->ddbsymcnt; j++) {
 707                                 es = &ef->ddbsymtab[j];
 708                                 if (es->st_shndx != i)
 709                                         continue;
 710                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 711                         }
 712                         mapbase += shdr[i].sh_size;
 713                         pb++;
 714                         break;
 715                 case SHT_REL:
 716                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 717                             M_WAITOK);
 718                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 719                         ef->reltab[rl].sec = shdr[i].sh_info;
 720                         error = vn_rdwr(UIO_READ, nd.ni_vp,
 721                             (void *)ef->reltab[rl].rel,
 722                             shdr[i].sh_size, shdr[i].sh_offset,
 723                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 724                             &resid, td);
 725                         if (error)
 726                                 goto out;
 727                         if (resid != 0){
 728                                 error = EINVAL;
 729                                 goto out;
 730                         }
 731                         rl++;
 732                         break;
 733                 case SHT_RELA:
 734                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 735                             M_WAITOK);
 736                         ef->relatab[ra].nrela =
 737                             shdr[i].sh_size / sizeof(Elf_Rela);
 738                         ef->relatab[ra].sec = shdr[i].sh_info;
 739                         error = vn_rdwr(UIO_READ, nd.ni_vp,
 740                             (void *)ef->relatab[ra].rela,
 741                             shdr[i].sh_size, shdr[i].sh_offset,
 742                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 743                             &resid, td);
 744                         if (error)
 745                                 goto out;
 746                         if (resid != 0){
 747                                 error = EINVAL;
 748                                 goto out;
 749                         }
 750                         ra++;
 751                         break;
 752                 }
 753         }
 754         if (pb != ef->nprogtab)
 755                 panic("lost progbits");
 756         if (rl != ef->nrel)
 757                 panic("lost rel");
 758         if (ra != ef->nrela)
 759                 panic("lost rela");
 760         if (mapbase != (vm_offset_t)ef->address + mapsize)
 761                 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 762                     mapbase, ef->address, mapsize,
 763                     (vm_offset_t)ef->address + mapsize);
 764
 765         /* Local intra-module relocations */
 766         link_elf_reloc_local(lf);
 767
 768         /* Pull in dependencies */
 769         error = linker_load_dependencies(lf);
 770         if (error)
 771                 goto out;
 772
 773         /* External relocations */
 774         error = relocate_file(ef);
 775         if (error)
 776                 goto out;
 777
 778         /* Notify MD code that a module is being loaded. */
 779         error = elf_cpu_load_file(lf);
 780         if (error)
 781                 goto out;
 782
 783         *result = lf;
 784
 785 out:
 786         if (error && lf)
 787                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 788         if (hdr)
 789                 free(hdr, M_LINKER);
 790         VOP_UNLOCK(nd.ni_vp, 0, td);
 791         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
 792         VFS_UNLOCK_GIANT(vfslocked);
 793
 794         return error;
 795 }
 796
 797 static void
 798 link_elf_unload_file(linker_file_t file)
 799 {
 800         elf_file_t ef = (elf_file_t) file;
 801         int i;
 802
 803         /* Notify MD code that a module is being unloaded. */
 804         elf_cpu_unload_file(file);
 805
 806         if (ef->preloaded) {
 807                 if (ef->reltab)
 808                         free(ef->reltab, M_LINKER);
 809                 if (ef->relatab)
 810                         free(ef->relatab, M_LINKER);
 811                 if (ef->progtab)
 812                         free(ef->progtab, M_LINKER);
 813                 if (file->filename != NULL)
 814                         preload_delete_name(file->filename);
 815                 /* XXX reclaim module memory? */
 816                 return;
 817         }
 818
 819         for (i = 0; i < ef->nrel; i++)
 820                 if (ef->reltab[i].rel)
 821                         free(ef->reltab[i].rel, M_LINKER);
 822         for (i = 0; i < ef->nrela; i++)
 823                 if (ef->relatab[i].rela)
 824                         free(ef->relatab[i].rela, M_LINKER);
 825         if (ef->reltab)
 826                 free(ef->reltab, M_LINKER);
 827         if (ef->relatab)
 828                 free(ef->relatab, M_LINKER);
 829         if (ef->progtab)
 830                 free(ef->progtab, M_LINKER);
 831
 832         if (ef->object) {
 833                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
 834                     (vm_offset_t) ef->address +
 835                     (ef->object->size << PAGE_SHIFT));
 836         }
 837         if (ef->e_shdr)
 838                 free(ef->e_shdr, M_LINKER);
 839         if (ef->ddbsymtab)
 840                 free(ef->ddbsymtab, M_LINKER);
 841         if (ef->ddbstrtab)
 842                 free(ef->ddbstrtab, M_LINKER);
 843         if (ef->shstrtab)
 844                 free(ef->shstrtab, M_LINKER);
 845 }
 846
 847 static const char *
 848 symbol_name(elf_file_t ef, Elf_Size r_info)
 849 {
 850         const Elf_Sym *ref;
 851
 852         if (ELF_R_SYM(r_info)) {
 853                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
 854                 return ef->ddbstrtab + ref->st_name;
 855         } else
 856                 return NULL;
 857 }
 858
 859 static Elf_Addr
 860 findbase(elf_file_t ef, int sec)
 861 {
 862         int i;
 863         Elf_Addr base = 0;
 864
 865         for (i = 0; i < ef->nprogtab; i++) {
 866                 if (sec == ef->progtab[i].sec) {
 867                         base = (Elf_Addr)ef->progtab[i].addr;
 868                         break;
 869                 }
 870         }
 871         return base;
 872 }
 873
 874 static int
 875 relocate_file(elf_file_t ef)
 876 {
 877         const Elf_Rel *rellim;
 878         const Elf_Rel *rel;
 879         const Elf_Rela *relalim;
 880         const Elf_Rela *rela;
 881         const char *symname;
 882         const Elf_Sym *sym;
 883         int i;
 884         Elf_Size symidx;
 885         Elf_Addr base;
 886
 887
 888         /* Perform relocations without addend if there are any: */
 889         for (i = 0; i < ef->nrel; i++) {
 890                 rel = ef->reltab[i].rel;
 891                 if (rel == NULL)
 892                         panic("lost a reltab!");
 893                 rellim = rel + ef->reltab[i].nrel;
 894                 base = findbase(ef, ef->reltab[i].sec);
 895                 if (base == 0)
 896                         panic("lost base for reltab");
 897                 for ( ; rel < rellim; rel++) {
 898                         symidx = ELF_R_SYM(rel->r_info);
 899                         if (symidx >= ef->ddbsymcnt)
 900                                 continue;
 901                         sym = ef->ddbsymtab + symidx;
 902                         /* Local relocs are already done */
 903                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 904                                 continue;
 905                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
 906                             elf_obj_lookup)) {
 907                                 symname = symbol_name(ef, rel->r_info);
 908                                 printf("link_elf_obj: symbol %s undefined\n",
 909                                     symname);
 910                                 return ENOENT;
 911                         }
 912                 }
 913         }
 914
 915         /* Perform relocations with addend if there are any: */
 916         for (i = 0; i < ef->nrela; i++) {
 917                 rela = ef->relatab[i].rela;
 918                 if (rela == NULL)
 919                         panic("lost a relatab!");
 920                 relalim = rela + ef->relatab[i].nrela;
 921                 base = findbase(ef, ef->relatab[i].sec);
 922                 if (base == 0)
 923                         panic("lost base for relatab");
 924                 for ( ; rela < relalim; rela++) {
 925                         symidx = ELF_R_SYM(rela->r_info);
 926                         if (symidx >= ef->ddbsymcnt)
 927                                 continue;
 928                         sym = ef->ddbsymtab + symidx;
 929                         /* Local relocs are already done */
 930                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
 931                                 continue;
 932                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
 933                             elf_obj_lookup)) {
 934                                 symname = symbol_name(ef, rela->r_info);
 935                                 printf("link_elf_obj: symbol %s undefined\n",
 936                                     symname);
 937                                 return ENOENT;
 938                         }
 939                 }
 940         }
 941
 942         return 0;
 943 }
 944
 945 static int
 946 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
 947 {
 948         elf_file_t ef = (elf_file_t) lf;
 949         const Elf_Sym *symp;
 950         const char *strp;
 951         int i;
 952
 953         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
 954                 strp = ef->ddbstrtab + symp->st_name;
 955                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
 956                         *sym = (c_linker_sym_t) symp;
 957                         return 0;
 958                 }
 959         }
 960         return ENOENT;
 961 }
 962
 963 static int
 964 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
 965     linker_symval_t *symval)
 966 {
 967         elf_file_t ef = (elf_file_t) lf;
 968         const Elf_Sym *es = (const Elf_Sym*) sym;
 969
 970         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
 971                 symval->name = ef->ddbstrtab + es->st_name;
 972                 symval->value = (caddr_t)es->st_value;
 973                 symval->size = es->st_size;
 974                 return 0;
 975         }
 976         return ENOENT;
 977 }
 978
 979 static int
 980 link_elf_search_symbol(linker_file_t lf, caddr_t value,
 981     c_linker_sym_t *sym, long *diffp)
 982 {
 983         elf_file_t ef = (elf_file_t) lf;
 984         u_long off = (uintptr_t) (void *) value;
 985         u_long diff = off;
 986         u_long st_value;
 987         const Elf_Sym *es;
 988         const Elf_Sym *best = 0;
 989         int i;
 990
 991         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
 992                 if (es->st_name == 0)
 993                         continue;
 994                 st_value = es->st_value;
 995                 if (off >= st_value) {
 996                         if (off - st_value < diff) {
 997                                 diff = off - st_value;
 998                                 best = es;
 999                                 if (diff == 0)
1000                                         break;
1001                         } else if (off - st_value == diff) {
1002                                 best = es;
1003                         }
1004                 }
1005         }
1006         if (best == 0)
1007                 *diffp = off;
1008         else
1009                 *diffp = diff;
1010         *sym = (c_linker_sym_t) best;
1011
1012         return 0;
1013 }
1014
1015 /*
1016  * Look up a linker set on an ELF system.
1017  */
1018 static int
1019 link_elf_lookup_set(linker_file_t lf, const char *name,
1020     void ***startp, void ***stopp, int *countp)
1021 {
1022         elf_file_t ef = (elf_file_t)lf;
1023         void **start, **stop;
1024         int i, count;
1025
1026         /* Relative to section number */
1027         for (i = 0; i < ef->nprogtab; i++) {
1028                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1029                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1030                         start  = (void **)ef->progtab[i].addr;
1031                         stop = (void **)((char *)ef->progtab[i].addr +
1032                             ef->progtab[i].size);
1033                         count = stop - start;
1034                         if (startp)
1035                                 *startp = start;
1036                         if (stopp)
1037                                 *stopp = stop;
1038                         if (countp)
1039                                 *countp = count;
1040                         return (0);
1041                 }
1042         }
1043         return (ESRCH);
1044 }
1045
1046 static int
1047 link_elf_each_function_name(linker_file_t file,
1048     int (*callback)(const char *, void *), void *opaque)
1049 {
1050         elf_file_t ef = (elf_file_t)file;
1051         const Elf_Sym *symp;
1052         int i, error;
1053
1054         /* Exhaustive search */
1055         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1056                 if (symp->st_value != 0 &&
1057                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1058                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1059                         if (error)
1060                                 return (error);
1061                 }
1062         }
1063         return (0);
1064 }
1065
1066 /*
1067  * Symbol lookup function that can be used when the symbol index is known (ie
1068  * in relocations). It uses the symbol index instead of doing a fully fledged
1069  * hash table based lookup when such is valid. For example for local symbols.
1070  * This is not only more efficient, it's also more correct. It's not always
1071  * the case that the symbol can be found through the hash table.
1072  */
1073 static Elf_Addr
1074 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
1075 {
1076         elf_file_t ef = (elf_file_t)lf;
1077         const Elf_Sym *sym;
1078         const char *symbol;
1079         Elf_Addr ret;
1080
1081         /* Don't even try to lookup the symbol if the index is bogus. */
1082         if (symidx >= ef->ddbsymcnt)
1083                 return (0);
1084
1085         sym = ef->ddbsymtab + symidx;
1086
1087         /* Quick answer if there is a definition included. */
1088         if (sym->st_shndx != SHN_UNDEF)
1089                 return (sym->st_value);
1090
1091         /* If we get here, then it is undefined and needs a lookup. */
1092         switch (ELF_ST_BIND(sym->st_info)) {
1093         case STB_LOCAL:
1094                 /* Local, but undefined? huh? */
1095                 return (0);
1096
1097         case STB_GLOBAL:
1098                 /* Relative to Data or Function name */
1099                 symbol = ef->ddbstrtab + sym->st_name;
1100
1101                 /* Force a lookup failure if the symbol name is bogus. */
1102                 if (*symbol == 0)
1103                         return (0);
1104                 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
1105                 return ret;
1106
1107         case STB_WEAK:
1108                 printf("link_elf_obj: Weak symbols not supported\n");
1109                 return (0);
1110
1111         default:
1112                 return (0);
1113         }
1114 }
1115
1116 static void
1117 link_elf_reloc_local(linker_file_t lf)
1118 {
1119         elf_file_t ef = (elf_file_t)lf;
1120         const Elf_Rel *rellim;
1121         const Elf_Rel *rel;
1122         const Elf_Rela *relalim;
1123         const Elf_Rela *rela;
1124         const Elf_Sym *sym;
1125         Elf_Addr base;
1126         int i;
1127         Elf_Size symidx;
1128
1129         /* Perform relocations without addend if there are any: */
1130         for (i = 0; i < ef->nrel; i++) {
1131                 rel = ef->reltab[i].rel;
1132                 if (rel == NULL)
1133                         panic("lost a reltab!");
1134                 rellim = rel + ef->reltab[i].nrel;
1135                 base = findbase(ef, ef->reltab[i].sec);
1136                 if (base == 0)
1137                         panic("lost base for reltab");
1138                 for ( ; rel < rellim; rel++) {
1139                         symidx = ELF_R_SYM(rel->r_info);
1140                         if (symidx >= ef->ddbsymcnt)
1141                                 continue;
1142                         sym = ef->ddbsymtab + symidx;
1143                         /* Only do local relocs */
1144                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1145                                 continue;
1146                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1147                             elf_obj_lookup);
1148                 }
1149         }
1150
1151         /* Perform relocations with addend if there are any: */
1152         for (i = 0; i < ef->nrela; i++) {
1153                 rela = ef->relatab[i].rela;
1154                 if (rela == NULL)
1155                         panic("lost a relatab!");
1156                 relalim = rela + ef->relatab[i].nrela;
1157                 base = findbase(ef, ef->relatab[i].sec);
1158                 if (base == 0)
1159                         panic("lost base for relatab");
1160                 for ( ; rela < relalim; rela++) {
1161                         symidx = ELF_R_SYM(rela->r_info);
1162                         if (symidx >= ef->ddbsymcnt)
1163                                 continue;
1164                         sym = ef->ddbsymtab + symidx;
1165                         /* Only do local relocs */
1166                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1167                                 continue;
1168                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1169                             elf_obj_lookup);
1170                 }
1171         }
1172 }