sys/kern/link_elf_obj.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 1998-2000 Doug Rabson
   5  * Copyright (c) 2004 Peter Wemm
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33 #include "opt_ddb.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/lock.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/mount.h>
  42 #include <sys/proc.h>
  43 #include <sys/namei.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/vnode.h>
  46 #include <sys/linker.h>
  47
  48 #include <machine/elf.h>
  49
  50 #include <net/vnet.h>
  51
  52 #include <security/mac/mac_framework.h>
  53
  54 #include <vm/vm.h>
  55 #include <vm/vm_param.h>
  56 #include <vm/vm_object.h>
  57 #include <vm/vm_kern.h>
  58 #include <vm/vm_extern.h>
  59 #include <vm/pmap.h>
  60 #include <vm/vm_map.h>
  61
  62 #include <sys/link_elf.h>
  63
  64 #ifdef DDB_CTF
  65 #include <contrib/zlib/zlib.h>
  66 #endif
  67
  68 #include "linker_if.h"
  69
  70 typedef struct {
  71         void            *addr;
  72         Elf_Off         size;
  73         int             flags;
  74         int             sec;    /* Original section */
  75         char            *name;
  76 } Elf_progent;
  77
  78 typedef struct {
  79         Elf_Rel         *rel;
  80         int             nrel;
  81         int             sec;
  82 } Elf_relent;
  83
  84 typedef struct {
  85         Elf_Rela        *rela;
  86         int             nrela;
  87         int             sec;
  88 } Elf_relaent;
  89
  90
  91 typedef struct elf_file {
  92         struct linker_file lf;          /* Common fields */
  93
  94         int             preloaded;
  95         caddr_t         address;        /* Relocation address */
  96         vm_object_t     object;         /* VM object to hold file pages */
  97         Elf_Shdr        *e_shdr;
  98
  99         Elf_progent     *progtab;
 100         u_int           nprogtab;
 101
 102         Elf_relaent     *relatab;
 103         u_int           nrelatab;
 104
 105         Elf_relent      *reltab;
 106         int             nreltab;
 107
 108         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 109         long            ddbsymcnt;      /* Number of symbols */
 110         caddr_t         ddbstrtab;      /* String table */
 111         long            ddbstrcnt;      /* number of bytes in string table */
 112
 113         caddr_t         shstrtab;       /* Section name string table */
 114         long            shstrcnt;       /* number of bytes in string table */
 115
 116         caddr_t         ctftab;         /* CTF table */
 117         long            ctfcnt;         /* number of bytes in CTF table */
 118         caddr_t         ctfoff;         /* CTF offset table */
 119         caddr_t         typoff;         /* Type offset table */
 120         long            typlen;         /* Number of type entries. */
 121
 122 } *elf_file_t;
 123
 124 #include <kern/kern_ctf.c>
 125
 126 static int      link_elf_link_preload(linker_class_t cls,
 127                     const char *, linker_file_t *);
 128 static int      link_elf_link_preload_finish(linker_file_t);
 129 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 130 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 131                     c_linker_sym_t *);
 132 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 133                     linker_symval_t *);
 134 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 135                     c_linker_sym_t *sym, long *diffp);
 136
 137 static void     link_elf_unload_file(linker_file_t);
 138 static int      link_elf_lookup_set(linker_file_t, const char *,
 139                     void ***, void ***, int *);
 140 static int      link_elf_each_function_name(linker_file_t,
 141                     int (*)(const char *, void *), void *);
 142 static int      link_elf_each_function_nameval(linker_file_t,
 143                                 linker_function_nameval_callback_t,
 144                                 void *);
 145 static int      link_elf_reloc_local(linker_file_t, bool);
 146 static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
 147 static long     link_elf_strtab_get(linker_file_t, caddr_t *);
 148
 149 static int      elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
 150                     Elf_Addr *);
 151
 152 static kobj_method_t link_elf_methods[] = {
 153         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 154         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 155         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 156         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 157         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 158         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 159         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 160         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 161         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 162         KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
 163         KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
 164         KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
 165         KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
 166         KOBJMETHOD_END
 167 };
 168
 169 static struct linker_class link_elf_class = {
 170 #if ELF_TARG_CLASS == ELFCLASS32
 171         "elf32_obj",
 172 #else
 173         "elf64_obj",
 174 #endif
 175         link_elf_methods, sizeof(struct elf_file)
 176 };
 177
 178 static int      relocate_file(elf_file_t ef);
 179 static void     elf_obj_cleanup_globals_cache(elf_file_t);
 180
 181 static void
 182 link_elf_error(const char *filename, const char *s)
 183 {
 184         if (filename == NULL)
 185                 printf("kldload: %s\n", s);
 186         else
 187                 printf("kldload: %s: %s\n", filename, s);
 188 }
 189
 190 static void
 191 link_elf_init(void *arg)
 192 {
 193
 194         linker_add_class(&link_elf_class);
 195 }
 196
 197 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);
 198
 199 static int
 200 link_elf_link_preload(linker_class_t cls, const char *filename,
 201     linker_file_t *result)
 202 {
 203         Elf_Ehdr *hdr;
 204         Elf_Shdr *shdr;
 205         Elf_Sym *es;
 206         void *modptr, *baseptr, *sizeptr;
 207         char *type;
 208         elf_file_t ef;
 209         linker_file_t lf;
 210         Elf_Addr off;
 211         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 212
 213         /* Look to see if we have the file preloaded */
 214         modptr = preload_search_by_name(filename);
 215         if (modptr == NULL)
 216                 return ENOENT;
 217
 218         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 219         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 220         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 221         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 222             MODINFOMD_ELFHDR);
 223         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 224             MODINFOMD_SHDR);
 225         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 226             " obj module") != 0 &&
 227             strcmp(type, "elf obj module") != 0)) {
 228                 return (EFTYPE);
 229         }
 230         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 231             shdr == NULL)
 232                 return (EINVAL);
 233
 234         lf = linker_make_file(filename, &link_elf_class);
 235         if (lf == NULL)
 236                 return (ENOMEM);
 237
 238         ef = (elf_file_t)lf;
 239         ef->preloaded = 1;
 240         ef->address = *(caddr_t *)baseptr;
 241         lf->address = *(caddr_t *)baseptr;
 242         lf->size = *(size_t *)sizeptr;
 243
 244         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 245             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 246             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 247             hdr->e_version != EV_CURRENT ||
 248             hdr->e_type != ET_REL ||
 249             hdr->e_machine != ELF_TARG_MACH) {
 250                 error = EFTYPE;
 251                 goto out;
 252         }
 253         ef->e_shdr = shdr;
 254
 255         /* Scan the section header for information and table sizing. */
 256         symtabindex = -1;
 257         symstrindex = -1;
 258         for (i = 0; i < hdr->e_shnum; i++) {
 259                 switch (shdr[i].sh_type) {
 260                 case SHT_PROGBITS:
 261                 case SHT_NOBITS:
 262 #ifdef __amd64__
 263                 case SHT_X86_64_UNWIND:
 264 #endif
 265                         /* Ignore sections not loaded by the loader. */
 266                         if (shdr[i].sh_addr == 0)
 267                                 break;
 268                         ef->nprogtab++;
 269                         break;
 270                 case SHT_SYMTAB:
 271                         symtabindex = i;
 272                         symstrindex = shdr[i].sh_link;
 273                         break;
 274                 case SHT_REL:
 275                         /*
 276                          * Ignore relocation tables for sections not
 277                          * loaded by the loader.
 278                          */
 279                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 280                                 break;
 281                         ef->nreltab++;
 282                         break;
 283                 case SHT_RELA:
 284                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 285                                 break;
 286                         ef->nrelatab++;
 287                         break;
 288                 }
 289         }
 290
 291         shstrindex = hdr->e_shstrndx;
 292         if (ef->nprogtab == 0 || symstrindex < 0 ||
 293             symstrindex >= hdr->e_shnum ||
 294             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 295             shstrindex >= hdr->e_shnum ||
 296             shdr[shstrindex].sh_type != SHT_STRTAB) {
 297                 printf("%s: bad/missing section headers\n", filename);
 298                 error = ENOEXEC;
 299                 goto out;
 300         }
 301
 302         /* Allocate space for tracking the load chunks */
 303         if (ef->nprogtab != 0)
 304                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 305                     M_LINKER, M_WAITOK | M_ZERO);
 306         if (ef->nreltab != 0)
 307                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 308                     M_LINKER, M_WAITOK | M_ZERO);
 309         if (ef->nrelatab != 0)
 310                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 311                     M_LINKER, M_WAITOK | M_ZERO);
 312         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 313             (ef->nreltab != 0 && ef->reltab == NULL) ||
 314             (ef->nrelatab != 0 && ef->relatab == NULL)) {
 315                 error = ENOMEM;
 316                 goto out;
 317         }
 318
 319         /* XXX, relocate the sh_addr fields saved by the loader. */
 320         off = 0;
 321         for (i = 0; i < hdr->e_shnum; i++) {
 322                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 323                         off = shdr[i].sh_addr;
 324         }
 325         for (i = 0; i < hdr->e_shnum; i++) {
 326                 if (shdr[i].sh_addr != 0)
 327                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 328                             (Elf_Addr)ef->address;
 329         }
 330
 331         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 332         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 333         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 334         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 335         ef->shstrcnt = shdr[shstrindex].sh_size;
 336         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 337
 338         /* Now fill out progtab and the relocation tables. */
 339         pb = 0;
 340         rl = 0;
 341         ra = 0;
 342         for (i = 0; i < hdr->e_shnum; i++) {
 343                 switch (shdr[i].sh_type) {
 344                 case SHT_PROGBITS:
 345                 case SHT_NOBITS:
 346 #ifdef __amd64__
 347                 case SHT_X86_64_UNWIND:
 348 #endif
 349                         if (shdr[i].sh_addr == 0)
 350                                 break;
 351                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 352                         if (shdr[i].sh_type == SHT_PROGBITS)
 353                                 ef->progtab[pb].name = "<<PROGBITS>>";
 354 #ifdef __amd64__
 355                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 356                                 ef->progtab[pb].name = "<<UNWIND>>";
 357 #endif
 358                         else
 359                                 ef->progtab[pb].name = "<<NOBITS>>";
 360                         ef->progtab[pb].size = shdr[i].sh_size;
 361                         ef->progtab[pb].sec = i;
 362                         if (ef->shstrtab && shdr[i].sh_name != 0)
 363                                 ef->progtab[pb].name =
 364                                     ef->shstrtab + shdr[i].sh_name;
 365                         if (ef->progtab[pb].name != NULL &&
 366                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 367                                 void *dpcpu;
 368
 369                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
 370                                 if (dpcpu == NULL) {
 371                                         printf("%s: pcpu module space is out "
 372                                             "of space; cannot allocate %#jx "
 373                                             "for %s\n", __func__,
 374                                             (uintmax_t)shdr[i].sh_size,
 375                                             filename);
 376                                         error = ENOSPC;
 377                                         goto out;
 378                                 }
 379                                 memcpy(dpcpu, ef->progtab[pb].addr,
 380                                     ef->progtab[pb].size);
 381                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
 382                                 ef->progtab[pb].addr = dpcpu;
 383 #ifdef VIMAGE
 384                         } else if (ef->progtab[pb].name != NULL &&
 385                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 386                                 void *vnet_data;
 387
 388                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
 389                                 if (vnet_data == NULL) {
 390                                         printf("%s: vnet module space is out "
 391                                             "of space; cannot allocate %#jx "
 392                                             "for %s\n", __func__,
 393                                             (uintmax_t)shdr[i].sh_size,
 394                                             filename);
 395                                         error = ENOSPC;
 396                                         goto out;
 397                                 }
 398                                 memcpy(vnet_data, ef->progtab[pb].addr,
 399                                     ef->progtab[pb].size);
 400                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
 401                                 ef->progtab[pb].addr = vnet_data;
 402 #endif
 403                         } else if (ef->progtab[pb].name != NULL &&
 404                             !strcmp(ef->progtab[pb].name, ".ctors")) {
 405                                 lf->ctors_addr = ef->progtab[pb].addr;
 406                                 lf->ctors_size = shdr[i].sh_size;
 407                         }
 408
 409                         /* Update all symbol values with the offset. */
 410                         for (j = 0; j < ef->ddbsymcnt; j++) {
 411                                 es = &ef->ddbsymtab[j];
 412                                 if (es->st_shndx != i)
 413                                         continue;
 414                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 415                         }
 416                         pb++;
 417                         break;
 418                 case SHT_REL:
 419                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 420                                 break;
 421                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 422                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 423                         ef->reltab[rl].sec = shdr[i].sh_info;
 424                         rl++;
 425                         break;
 426                 case SHT_RELA:
 427                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 428                                 break;
 429                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 430                         ef->relatab[ra].nrela =
 431                             shdr[i].sh_size / sizeof(Elf_Rela);
 432                         ef->relatab[ra].sec = shdr[i].sh_info;
 433                         ra++;
 434                         break;
 435                 }
 436         }
 437         if (pb != ef->nprogtab) {
 438                 printf("%s: lost progbits\n", filename);
 439                 error = ENOEXEC;
 440                 goto out;
 441         }
 442         if (rl != ef->nreltab) {
 443                 printf("%s: lost reltab\n", filename);
 444                 error = ENOEXEC;
 445                 goto out;
 446         }
 447         if (ra != ef->nrelatab) {
 448                 printf("%s: lost relatab\n", filename);
 449                 error = ENOEXEC;
 450                 goto out;
 451         }
 452
 453         /* Local intra-module relocations */
 454         error = link_elf_reloc_local(lf, false);
 455         if (error != 0)
 456                 goto out;
 457         *result = lf;
 458         return (0);
 459
 460 out:
 461         /* preload not done this way */
 462         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 463         return (error);
 464 }
 465
 466 static void
 467 link_elf_invoke_ctors(caddr_t addr, size_t size)
 468 {
 469         void (**ctor)(void);
 470         size_t i, cnt;
 471
 472         if (addr == NULL || size == 0)
 473                 return;
 474         cnt = size / sizeof(*ctor);
 475         ctor = (void *)addr;
 476         for (i = 0; i < cnt; i++) {
 477                 if (ctor[i] != NULL)
 478                         (*ctor[i])();
 479         }
 480 }
 481
 482 static int
 483 link_elf_link_preload_finish(linker_file_t lf)
 484 {
 485         elf_file_t ef;
 486         int error;
 487
 488         ef = (elf_file_t)lf;
 489         error = relocate_file(ef);
 490         if (error)
 491                 return (error);
 492
 493         /* Notify MD code that a module is being loaded. */
 494         error = elf_cpu_load_file(lf);
 495         if (error)
 496                 return (error);
 497
 498 #if defined(__i386__) || defined(__amd64__)
 499         /* Now ifuncs. */
 500         error = link_elf_reloc_local(lf, true);
 501         if (error != 0)
 502                 return (error);
 503 #endif
 504
 505         /* Invoke .ctors */
 506         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 507         return (0);
 508 }
 509
 510 static int
 511 link_elf_load_file(linker_class_t cls, const char *filename,
 512     linker_file_t *result)
 513 {
 514         struct nameidata *nd;
 515         struct thread *td = curthread;  /* XXX */
 516         Elf_Ehdr *hdr;
 517         Elf_Shdr *shdr;
 518         Elf_Sym *es;
 519         int nbytes, i, j;
 520         vm_offset_t mapbase;
 521         size_t mapsize;
 522         int error = 0;
 523         ssize_t resid;
 524         int flags;
 525         elf_file_t ef;
 526         linker_file_t lf;
 527         int symtabindex;
 528         int symstrindex;
 529         int shstrindex;
 530         int nsym;
 531         int pb, rl, ra;
 532         int alignmask;
 533
 534         shdr = NULL;
 535         lf = NULL;
 536         mapsize = 0;
 537         hdr = NULL;
 538
 539         nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
 540         NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 541         flags = FREAD;
 542         error = vn_open(nd, &flags, 0, NULL);
 543         if (error) {
 544                 free(nd, M_TEMP);
 545                 return error;
 546         }
 547         NDFREE(nd, NDF_ONLY_PNBUF);
 548         if (nd->ni_vp->v_type != VREG) {
 549                 error = ENOEXEC;
 550                 goto out;
 551         }
 552 #ifdef MAC
 553         error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
 554         if (error) {
 555                 goto out;
 556         }
 557 #endif
 558
 559         /* Read the elf header from the file. */
 560         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 561         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
 562             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 563             &resid, td);
 564         if (error)
 565                 goto out;
 566         if (resid != 0){
 567                 error = ENOEXEC;
 568                 goto out;
 569         }
 570
 571         if (!IS_ELF(*hdr)) {
 572                 error = ENOEXEC;
 573                 goto out;
 574         }
 575
 576         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 577             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 578                 link_elf_error(filename, "Unsupported file layout");
 579                 error = ENOEXEC;
 580                 goto out;
 581         }
 582         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 583             || hdr->e_version != EV_CURRENT) {
 584                 link_elf_error(filename, "Unsupported file version");
 585                 error = ENOEXEC;
 586                 goto out;
 587         }
 588         if (hdr->e_type != ET_REL) {
 589                 error = ENOSYS;
 590                 goto out;
 591         }
 592         if (hdr->e_machine != ELF_TARG_MACH) {
 593                 link_elf_error(filename, "Unsupported machine");
 594                 error = ENOEXEC;
 595                 goto out;
 596         }
 597
 598         lf = linker_make_file(filename, &link_elf_class);
 599         if (!lf) {
 600                 error = ENOMEM;
 601                 goto out;
 602         }
 603         ef = (elf_file_t) lf;
 604         ef->nprogtab = 0;
 605         ef->e_shdr = 0;
 606         ef->nreltab = 0;
 607         ef->nrelatab = 0;
 608
 609         /* Allocate and read in the section header */
 610         nbytes = hdr->e_shnum * hdr->e_shentsize;
 611         if (nbytes == 0 || hdr->e_shoff == 0 ||
 612             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 613                 error = ENOEXEC;
 614                 goto out;
 615         }
 616         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 617         ef->e_shdr = shdr;
 618         error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
 619             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 620             NOCRED, &resid, td);
 621         if (error)
 622                 goto out;
 623         if (resid) {
 624                 error = ENOEXEC;
 625                 goto out;
 626         }
 627
 628         /* Scan the section header for information and table sizing. */
 629         nsym = 0;
 630         symtabindex = -1;
 631         symstrindex = -1;
 632         for (i = 0; i < hdr->e_shnum; i++) {
 633                 if (shdr[i].sh_size == 0)
 634                         continue;
 635                 switch (shdr[i].sh_type) {
 636                 case SHT_PROGBITS:
 637                 case SHT_NOBITS:
 638 #ifdef __amd64__
 639                 case SHT_X86_64_UNWIND:
 640 #endif
 641                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 642                                 break;
 643                         ef->nprogtab++;
 644                         break;
 645                 case SHT_SYMTAB:
 646                         nsym++;
 647                         symtabindex = i;
 648                         symstrindex = shdr[i].sh_link;
 649                         break;
 650                 case SHT_REL:
 651                         /*
 652                          * Ignore relocation tables for unallocated
 653                          * sections.
 654                          */
 655                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 656                                 break;
 657                         ef->nreltab++;
 658                         break;
 659                 case SHT_RELA:
 660                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 661                                 break;
 662                         ef->nrelatab++;
 663                         break;
 664                 case SHT_STRTAB:
 665                         break;
 666                 }
 667         }
 668         if (ef->nprogtab == 0) {
 669                 link_elf_error(filename, "file has no contents");
 670                 error = ENOEXEC;
 671                 goto out;
 672         }
 673         if (nsym != 1) {
 674                 /* Only allow one symbol table for now */
 675                 link_elf_error(filename,
 676                     "file must have exactly one symbol table");
 677                 error = ENOEXEC;
 678                 goto out;
 679         }
 680         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 681             shdr[symstrindex].sh_type != SHT_STRTAB) {
 682                 link_elf_error(filename, "file has invalid symbol strings");
 683                 error = ENOEXEC;
 684                 goto out;
 685         }
 686
 687         /* Allocate space for tracking the load chunks */
 688         if (ef->nprogtab != 0)
 689                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 690                     M_LINKER, M_WAITOK | M_ZERO);
 691         if (ef->nreltab != 0)
 692                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 693                     M_LINKER, M_WAITOK | M_ZERO);
 694         if (ef->nrelatab != 0)
 695                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 696                     M_LINKER, M_WAITOK | M_ZERO);
 697
 698         if (symtabindex == -1) {
 699                 link_elf_error(filename, "lost symbol table index");
 700                 error = ENOEXEC;
 701                 goto out;
 702         }
 703         /* Allocate space for and load the symbol table */
 704         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 705         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 706         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 707             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 708             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 709             &resid, td);
 710         if (error)
 711                 goto out;
 712         if (resid != 0){
 713                 error = EINVAL;
 714                 goto out;
 715         }
 716
 717         /* Allocate space for and load the symbol strings */
 718         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 719         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 720         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 721             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 722             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 723             &resid, td);
 724         if (error)
 725                 goto out;
 726         if (resid != 0){
 727                 error = EINVAL;
 728                 goto out;
 729         }
 730
 731         /* Do we have a string table for the section names?  */
 732         shstrindex = -1;
 733         if (hdr->e_shstrndx != 0 &&
 734             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 735                 shstrindex = hdr->e_shstrndx;
 736                 ef->shstrcnt = shdr[shstrindex].sh_size;
 737                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 738                     M_WAITOK);
 739                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 740                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 741                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 742                     &resid, td);
 743                 if (error)
 744                         goto out;
 745                 if (resid != 0){
 746                         error = EINVAL;
 747                         goto out;
 748                 }
 749         }
 750
 751         /* Size up code/data(progbits) and bss(nobits). */
 752         alignmask = 0;
 753         for (i = 0; i < hdr->e_shnum; i++) {
 754                 if (shdr[i].sh_size == 0)
 755                         continue;
 756                 switch (shdr[i].sh_type) {
 757                 case SHT_PROGBITS:
 758                 case SHT_NOBITS:
 759 #ifdef __amd64__
 760                 case SHT_X86_64_UNWIND:
 761 #endif
 762                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 763                                 break;
 764                         alignmask = shdr[i].sh_addralign - 1;
 765                         mapsize += alignmask;
 766                         mapsize &= ~alignmask;
 767                         mapsize += shdr[i].sh_size;
 768                         break;
 769                 }
 770         }
 771
 772         /*
 773          * We know how much space we need for the text/data/bss/etc.
 774          * This stuff needs to be in a single chunk so that profiling etc
 775          * can get the bounds and gdb can associate offsets with modules
 776          */
 777         ef->object = vm_object_allocate(OBJT_PHYS, atop(round_page(mapsize)));
 778         if (ef->object == NULL) {
 779                 error = ENOMEM;
 780                 goto out;
 781         }
 782         ef->address = (caddr_t) vm_map_min(kernel_map);
 783
 784         /*
 785          * In order to satisfy amd64's architectural requirements on the
 786          * location of code and data in the kernel's address space, request a
 787          * mapping that is above the kernel.
 788          */
 789 #ifdef __amd64__
 790         mapbase = KERNBASE;
 791 #else
 792         mapbase = VM_MIN_KERNEL_ADDRESS;
 793 #endif
 794         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 795             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 796             VM_PROT_ALL, 0);
 797         if (error) {
 798                 vm_object_deallocate(ef->object);
 799                 ef->object = 0;
 800                 goto out;
 801         }
 802
 803         /* Wire the pages */
 804         error = vm_map_wire(kernel_map, mapbase,
 805             mapbase + round_page(mapsize),
 806             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 807         if (error != KERN_SUCCESS) {
 808                 error = ENOMEM;
 809                 goto out;
 810         }
 811
 812         /* Inform the kld system about the situation */
 813         lf->address = ef->address = (caddr_t)mapbase;
 814         lf->size = mapsize;
 815
 816         /*
 817          * Now load code/data(progbits), zero bss(nobits), allocate space for
 818          * and load relocs
 819          */
 820         pb = 0;
 821         rl = 0;
 822         ra = 0;
 823         alignmask = 0;
 824         for (i = 0; i < hdr->e_shnum; i++) {
 825                 if (shdr[i].sh_size == 0)
 826                         continue;
 827                 switch (shdr[i].sh_type) {
 828                 case SHT_PROGBITS:
 829                 case SHT_NOBITS:
 830 #ifdef __amd64__
 831                 case SHT_X86_64_UNWIND:
 832 #endif
 833                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 834                                 break;
 835                         alignmask = shdr[i].sh_addralign - 1;
 836                         mapbase += alignmask;
 837                         mapbase &= ~alignmask;
 838                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 839                                 ef->progtab[pb].name =
 840                                     ef->shstrtab + shdr[i].sh_name;
 841                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 842                                         lf->ctors_addr = (caddr_t)mapbase;
 843                                         lf->ctors_size = shdr[i].sh_size;
 844                                 }
 845                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 846                                 ef->progtab[pb].name = "<<PROGBITS>>";
 847 #ifdef __amd64__
 848                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 849                                 ef->progtab[pb].name = "<<UNWIND>>";
 850 #endif
 851                         else
 852                                 ef->progtab[pb].name = "<<NOBITS>>";
 853                         if (ef->progtab[pb].name != NULL &&
 854                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 855                                 ef->progtab[pb].addr =
 856                                     dpcpu_alloc(shdr[i].sh_size);
 857                                 if (ef->progtab[pb].addr == NULL) {
 858                                         printf("%s: pcpu module space is out "
 859                                             "of space; cannot allocate %#jx "
 860                                             "for %s\n", __func__,
 861                                             (uintmax_t)shdr[i].sh_size,
 862                                             filename);
 863                                 }
 864                         }
 865 #ifdef VIMAGE
 866                         else if (ef->progtab[pb].name != NULL &&
 867                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 868                                 ef->progtab[pb].addr =
 869                                     vnet_data_alloc(shdr[i].sh_size);
 870                                 if (ef->progtab[pb].addr == NULL) {
 871                                         printf("%s: vnet module space is out "
 872                                             "of space; cannot allocate %#jx "
 873                                             "for %s\n", __func__,
 874                                             (uintmax_t)shdr[i].sh_size,
 875                                             filename);
 876                                 }
 877                         }
 878 #endif
 879                         else
 880                                 ef->progtab[pb].addr =
 881                                     (void *)(uintptr_t)mapbase;
 882                         if (ef->progtab[pb].addr == NULL) {
 883                                 error = ENOSPC;
 884                                 goto out;
 885                         }
 886                         ef->progtab[pb].size = shdr[i].sh_size;
 887                         ef->progtab[pb].sec = i;
 888                         if (shdr[i].sh_type == SHT_PROGBITS
 889 #ifdef __amd64__
 890                             || shdr[i].sh_type == SHT_X86_64_UNWIND
 891 #endif
 892                             ) {
 893                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
 894                                     ef->progtab[pb].addr,
 895                                     shdr[i].sh_size, shdr[i].sh_offset,
 896                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 897                                     NOCRED, &resid, td);
 898                                 if (error)
 899                                         goto out;
 900                                 if (resid != 0){
 901                                         error = EINVAL;
 902                                         goto out;
 903                                 }
 904                                 /* Initialize the per-cpu or vnet area. */
 905                                 if (ef->progtab[pb].addr != (void *)mapbase &&
 906                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 907                                         dpcpu_copy(ef->progtab[pb].addr,
 908                                             shdr[i].sh_size);
 909 #ifdef VIMAGE
 910                                 else if (ef->progtab[pb].addr !=
 911                                     (void *)mapbase &&
 912                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 913                                         vnet_data_copy(ef->progtab[pb].addr,
 914                                             shdr[i].sh_size);
 915 #endif
 916                         } else
 917                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 918
 919                         /* Update all symbol values with the offset. */
 920                         for (j = 0; j < ef->ddbsymcnt; j++) {
 921                                 es = &ef->ddbsymtab[j];
 922                                 if (es->st_shndx != i)
 923                                         continue;
 924                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 925                         }
 926                         mapbase += shdr[i].sh_size;
 927                         pb++;
 928                         break;
 929                 case SHT_REL:
 930                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 931                                 break;
 932                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 933                             M_WAITOK);
 934                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 935                         ef->reltab[rl].sec = shdr[i].sh_info;
 936                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 937                             (void *)ef->reltab[rl].rel,
 938                             shdr[i].sh_size, shdr[i].sh_offset,
 939                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 940                             &resid, td);
 941                         if (error)
 942                                 goto out;
 943                         if (resid != 0){
 944                                 error = EINVAL;
 945                                 goto out;
 946                         }
 947                         rl++;
 948                         break;
 949                 case SHT_RELA:
 950                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 951                                 break;
 952                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 953                             M_WAITOK);
 954                         ef->relatab[ra].nrela =
 955                             shdr[i].sh_size / sizeof(Elf_Rela);
 956                         ef->relatab[ra].sec = shdr[i].sh_info;
 957                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 958                             (void *)ef->relatab[ra].rela,
 959                             shdr[i].sh_size, shdr[i].sh_offset,
 960                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 961                             &resid, td);
 962                         if (error)
 963                                 goto out;
 964                         if (resid != 0){
 965                                 error = EINVAL;
 966                                 goto out;
 967                         }
 968                         ra++;
 969                         break;
 970                 }
 971         }
 972         if (pb != ef->nprogtab) {
 973                 link_elf_error(filename, "lost progbits");
 974                 error = ENOEXEC;
 975                 goto out;
 976         }
 977         if (rl != ef->nreltab) {
 978                 link_elf_error(filename, "lost reltab");
 979                 error = ENOEXEC;
 980                 goto out;
 981         }
 982         if (ra != ef->nrelatab) {
 983                 link_elf_error(filename, "lost relatab");
 984                 error = ENOEXEC;
 985                 goto out;
 986         }
 987         if (mapbase != (vm_offset_t)ef->address + mapsize) {
 988                 printf(
 989                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 990                     filename != NULL ? filename : "<none>",
 991                     (u_long)mapbase, ef->address, (u_long)mapsize,
 992                     (u_long)(vm_offset_t)ef->address + mapsize);
 993                 error = ENOMEM;
 994                 goto out;
 995         }
 996
 997         /* Local intra-module relocations */
 998         error = link_elf_reloc_local(lf, false);
 999         if (error != 0)
1000                 goto out;
1001
1002         /* Pull in dependencies */
1003         VOP_UNLOCK(nd->ni_vp, 0);
1004         error = linker_load_dependencies(lf);
1005         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
1006         if (error)
1007                 goto out;
1008
1009         /* External relocations */
1010         error = relocate_file(ef);
1011         if (error)
1012                 goto out;
1013
1014         /* Notify MD code that a module is being loaded. */
1015         error = elf_cpu_load_file(lf);
1016         if (error)
1017                 goto out;
1018
1019 #if defined(__i386__) || defined(__amd64__)
1020         /* Now ifuncs. */
1021         error = link_elf_reloc_local(lf, true);
1022         if (error != 0)
1023                 goto out;
1024 #endif
1025
1026         /* Invoke .ctors */
1027         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
1028
1029         *result = lf;
1030
1031 out:
1032         VOP_UNLOCK(nd->ni_vp, 0);
1033         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1034         free(nd, M_TEMP);
1035         if (error && lf)
1036                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1037         free(hdr, M_LINKER);
1038
1039         return error;
1040 }
1041
1042 static void
1043 link_elf_unload_file(linker_file_t file)
1044 {
1045         elf_file_t ef = (elf_file_t) file;
1046         u_int i;
1047
1048         /* Notify MD code that a module is being unloaded. */
1049         elf_cpu_unload_file(file);
1050
1051         if (ef->progtab) {
1052                 for (i = 0; i < ef->nprogtab; i++) {
1053                         if (ef->progtab[i].size == 0)
1054                                 continue;
1055                         if (ef->progtab[i].name == NULL)
1056                                 continue;
1057                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1058                                 dpcpu_free(ef->progtab[i].addr,
1059                                     ef->progtab[i].size);
1060 #ifdef VIMAGE
1061                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1062                                 vnet_data_free(ef->progtab[i].addr,
1063                                     ef->progtab[i].size);
1064 #endif
1065                 }
1066         }
1067         if (ef->preloaded) {
1068                 free(ef->reltab, M_LINKER);
1069                 free(ef->relatab, M_LINKER);
1070                 free(ef->progtab, M_LINKER);
1071                 free(ef->ctftab, M_LINKER);
1072                 free(ef->ctfoff, M_LINKER);
1073                 free(ef->typoff, M_LINKER);
1074                 if (file->pathname != NULL)
1075                         preload_delete_name(file->pathname);
1076                 return;
1077         }
1078
1079         for (i = 0; i < ef->nreltab; i++)
1080                 free(ef->reltab[i].rel, M_LINKER);
1081         for (i = 0; i < ef->nrelatab; i++)
1082                 free(ef->relatab[i].rela, M_LINKER);
1083         free(ef->reltab, M_LINKER);
1084         free(ef->relatab, M_LINKER);
1085         free(ef->progtab, M_LINKER);
1086
1087         if (ef->object) {
1088                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1089                     (vm_offset_t) ef->address +
1090                     (ef->object->size << PAGE_SHIFT));
1091         }
1092         free(ef->e_shdr, M_LINKER);
1093         free(ef->ddbsymtab, M_LINKER);
1094         free(ef->ddbstrtab, M_LINKER);
1095         free(ef->shstrtab, M_LINKER);
1096         free(ef->ctftab, M_LINKER);
1097         free(ef->ctfoff, M_LINKER);
1098         free(ef->typoff, M_LINKER);
1099 }
1100
1101 static const char *
1102 symbol_name(elf_file_t ef, Elf_Size r_info)
1103 {
1104         const Elf_Sym *ref;
1105
1106         if (ELF_R_SYM(r_info)) {
1107                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1108                 return ef->ddbstrtab + ref->st_name;
1109         } else
1110                 return NULL;
1111 }
1112
1113 static Elf_Addr
1114 findbase(elf_file_t ef, int sec)
1115 {
1116         int i;
1117         Elf_Addr base = 0;
1118
1119         for (i = 0; i < ef->nprogtab; i++) {
1120                 if (sec == ef->progtab[i].sec) {
1121                         base = (Elf_Addr)ef->progtab[i].addr;
1122                         break;
1123                 }
1124         }
1125         return base;
1126 }
1127
1128 static int
1129 relocate_file(elf_file_t ef)
1130 {
1131         const Elf_Rel *rellim;
1132         const Elf_Rel *rel;
1133         const Elf_Rela *relalim;
1134         const Elf_Rela *rela;
1135         const char *symname;
1136         const Elf_Sym *sym;
1137         int i;
1138         Elf_Size symidx;
1139         Elf_Addr base;
1140
1141
1142         /* Perform relocations without addend if there are any: */
1143         for (i = 0; i < ef->nreltab; i++) {
1144                 rel = ef->reltab[i].rel;
1145                 if (rel == NULL) {
1146                         link_elf_error(ef->lf.filename, "lost a reltab!");
1147                         return (ENOEXEC);
1148                 }
1149                 rellim = rel + ef->reltab[i].nrel;
1150                 base = findbase(ef, ef->reltab[i].sec);
1151                 if (base == 0) {
1152                         link_elf_error(ef->lf.filename, "lost base for reltab");
1153                         return (ENOEXEC);
1154                 }
1155                 for ( ; rel < rellim; rel++) {
1156                         symidx = ELF_R_SYM(rel->r_info);
1157                         if (symidx >= ef->ddbsymcnt)
1158                                 continue;
1159                         sym = ef->ddbsymtab + symidx;
1160                         /* Local relocs are already done */
1161                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1162                                 continue;
1163                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1164                             elf_obj_lookup)) {
1165                                 symname = symbol_name(ef, rel->r_info);
1166                                 printf("link_elf_obj: symbol %s undefined\n",
1167                                     symname);
1168                                 return (ENOENT);
1169                         }
1170                 }
1171         }
1172
1173         /* Perform relocations with addend if there are any: */
1174         for (i = 0; i < ef->nrelatab; i++) {
1175                 rela = ef->relatab[i].rela;
1176                 if (rela == NULL) {
1177                         link_elf_error(ef->lf.filename, "lost a relatab!");
1178                         return (ENOEXEC);
1179                 }
1180                 relalim = rela + ef->relatab[i].nrela;
1181                 base = findbase(ef, ef->relatab[i].sec);
1182                 if (base == 0) {
1183                         link_elf_error(ef->lf.filename,
1184                             "lost base for relatab");
1185                         return (ENOEXEC);
1186                 }
1187                 for ( ; rela < relalim; rela++) {
1188                         symidx = ELF_R_SYM(rela->r_info);
1189                         if (symidx >= ef->ddbsymcnt)
1190                                 continue;
1191                         sym = ef->ddbsymtab + symidx;
1192                         /* Local relocs are already done */
1193                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1194                                 continue;
1195                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1196                             elf_obj_lookup)) {
1197                                 symname = symbol_name(ef, rela->r_info);
1198                                 printf("link_elf_obj: symbol %s undefined\n",
1199                                     symname);
1200                                 return (ENOENT);
1201                         }
1202                 }
1203         }
1204
1205         /*
1206          * Only clean SHN_FBSD_CACHED for successful return.  If we
1207          * modified symbol table for the object but found an
1208          * unresolved symbol, there is no reason to roll back.
1209          */
1210         elf_obj_cleanup_globals_cache(ef);
1211
1212         return (0);
1213 }
1214
1215 static int
1216 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1217 {
1218         elf_file_t ef = (elf_file_t) lf;
1219         const Elf_Sym *symp;
1220         const char *strp;
1221         int i;
1222
1223         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1224                 strp = ef->ddbstrtab + symp->st_name;
1225                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1226                         *sym = (c_linker_sym_t) symp;
1227                         return 0;
1228                 }
1229         }
1230         return ENOENT;
1231 }
1232
1233 static int
1234 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1235     linker_symval_t *symval)
1236 {
1237         elf_file_t ef;
1238         const Elf_Sym *es;
1239         caddr_t val;
1240
1241         ef = (elf_file_t) lf;
1242         es = (const Elf_Sym*) sym;
1243         val = (caddr_t)es->st_value;
1244         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1245                 symval->name = ef->ddbstrtab + es->st_name;
1246                 val = (caddr_t)es->st_value;
1247                 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1248                         val = ((caddr_t (*)(void))val)();
1249                 symval->value = val;
1250                 symval->size = es->st_size;
1251                 return 0;
1252         }
1253         return ENOENT;
1254 }
1255
1256 static int
1257 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1258     c_linker_sym_t *sym, long *diffp)
1259 {
1260         elf_file_t ef = (elf_file_t) lf;
1261         u_long off = (uintptr_t) (void *) value;
1262         u_long diff = off;
1263         u_long st_value;
1264         const Elf_Sym *es;
1265         const Elf_Sym *best = NULL;
1266         int i;
1267
1268         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1269                 if (es->st_name == 0)
1270                         continue;
1271                 st_value = es->st_value;
1272                 if (off >= st_value) {
1273                         if (off - st_value < diff) {
1274                                 diff = off - st_value;
1275                                 best = es;
1276                                 if (diff == 0)
1277                                         break;
1278                         } else if (off - st_value == diff) {
1279                                 best = es;
1280                         }
1281                 }
1282         }
1283         if (best == NULL)
1284                 *diffp = off;
1285         else
1286                 *diffp = diff;
1287         *sym = (c_linker_sym_t) best;
1288
1289         return 0;
1290 }
1291
1292 /*
1293  * Look up a linker set on an ELF system.
1294  */
1295 static int
1296 link_elf_lookup_set(linker_file_t lf, const char *name,
1297     void ***startp, void ***stopp, int *countp)
1298 {
1299         elf_file_t ef = (elf_file_t)lf;
1300         void **start, **stop;
1301         int i, count;
1302
1303         /* Relative to section number */
1304         for (i = 0; i < ef->nprogtab; i++) {
1305                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1306                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1307                         start  = (void **)ef->progtab[i].addr;
1308                         stop = (void **)((char *)ef->progtab[i].addr +
1309                             ef->progtab[i].size);
1310                         count = stop - start;
1311                         if (startp)
1312                                 *startp = start;
1313                         if (stopp)
1314                                 *stopp = stop;
1315                         if (countp)
1316                                 *countp = count;
1317                         return (0);
1318                 }
1319         }
1320         return (ESRCH);
1321 }
1322
1323 static int
1324 link_elf_each_function_name(linker_file_t file,
1325     int (*callback)(const char *, void *), void *opaque)
1326 {
1327         elf_file_t ef = (elf_file_t)file;
1328         const Elf_Sym *symp;
1329         int i, error;
1330
1331         /* Exhaustive search */
1332         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1333                 if (symp->st_value != 0 &&
1334                     (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1335                     ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1336                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1337                         if (error)
1338                                 return (error);
1339                 }
1340         }
1341         return (0);
1342 }
1343
1344 static int
1345 link_elf_each_function_nameval(linker_file_t file,
1346     linker_function_nameval_callback_t callback, void *opaque)
1347 {
1348         linker_symval_t symval;
1349         elf_file_t ef = (elf_file_t)file;
1350         const Elf_Sym* symp;
1351         int i, error;
1352
1353         /* Exhaustive search */
1354         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1355                 if (symp->st_value != 0 &&
1356                     (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1357                     ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1358                         error = link_elf_symbol_values(file,
1359                             (c_linker_sym_t)symp, &symval);
1360                         if (error)
1361                                 return (error);
1362                         error = callback(file, i, &symval, opaque);
1363                         if (error)
1364                                 return (error);
1365                 }
1366         }
1367         return (0);
1368 }
1369
1370 static void
1371 elf_obj_cleanup_globals_cache(elf_file_t ef)
1372 {
1373         Elf_Sym *sym;
1374         Elf_Size i;
1375
1376         for (i = 0; i < ef->ddbsymcnt; i++) {
1377                 sym = ef->ddbsymtab + i;
1378                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1379                         sym->st_shndx = SHN_UNDEF;
1380                         sym->st_value = 0;
1381                 }
1382         }
1383 }
1384
1385 /*
1386  * Symbol lookup function that can be used when the symbol index is known (ie
1387  * in relocations). It uses the symbol index instead of doing a fully fledged
1388  * hash table based lookup when such is valid. For example for local symbols.
1389  * This is not only more efficient, it's also more correct. It's not always
1390  * the case that the symbol can be found through the hash table.
1391  */
1392 static int
1393 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1394 {
1395         elf_file_t ef = (elf_file_t)lf;
1396         Elf_Sym *sym;
1397         const char *symbol;
1398         Elf_Addr res1;
1399
1400         /* Don't even try to lookup the symbol if the index is bogus. */
1401         if (symidx >= ef->ddbsymcnt) {
1402                 *res = 0;
1403                 return (EINVAL);
1404         }
1405
1406         sym = ef->ddbsymtab + symidx;
1407
1408         /* Quick answer if there is a definition included. */
1409         if (sym->st_shndx != SHN_UNDEF) {
1410                 res1 = (Elf_Addr)sym->st_value;
1411                 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1412                         res1 = ((Elf_Addr (*)(void))res1)();
1413                 *res = res1;
1414                 return (0);
1415         }
1416
1417         /* If we get here, then it is undefined and needs a lookup. */
1418         switch (ELF_ST_BIND(sym->st_info)) {
1419         case STB_LOCAL:
1420                 /* Local, but undefined? huh? */
1421                 *res = 0;
1422                 return (EINVAL);
1423
1424         case STB_GLOBAL:
1425         case STB_WEAK:
1426                 /* Relative to Data or Function name */
1427                 symbol = ef->ddbstrtab + sym->st_name;
1428
1429                 /* Force a lookup failure if the symbol name is bogus. */
1430                 if (*symbol == 0) {
1431                         *res = 0;
1432                         return (EINVAL);
1433                 }
1434                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1435
1436                 /*
1437                  * Cache global lookups during module relocation. The failure
1438                  * case is particularly expensive for callers, who must scan
1439                  * through the entire globals table doing strcmp(). Cache to
1440                  * avoid doing such work repeatedly.
1441                  *
1442                  * After relocation is complete, undefined globals will be
1443                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1444                  * above.
1445                  */
1446                 if (res1 != 0) {
1447                         sym->st_shndx = SHN_FBSD_CACHED;
1448                         sym->st_value = res1;
1449                         *res = res1;
1450                         return (0);
1451                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1452                         sym->st_value = 0;
1453                         *res = 0;
1454                         return (0);
1455                 }
1456                 return (EINVAL);
1457
1458         default:
1459                 return (EINVAL);
1460         }
1461 }
1462
1463 static void
1464 link_elf_fix_link_set(elf_file_t ef)
1465 {
1466         static const char startn[] = "__start_";
1467         static const char stopn[] = "__stop_";
1468         Elf_Sym *sym;
1469         const char *sym_name, *linkset_name;
1470         Elf_Addr startp, stopp;
1471         Elf_Size symidx;
1472         int start, i;
1473
1474         startp = stopp = 0;
1475         for (symidx = 1 /* zero entry is special */;
1476                 symidx < ef->ddbsymcnt; symidx++) {
1477                 sym = ef->ddbsymtab + symidx;
1478                 if (sym->st_shndx != SHN_UNDEF)
1479                         continue;
1480
1481                 sym_name = ef->ddbstrtab + sym->st_name;
1482                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1483                         start = 1;
1484                         linkset_name = sym_name + sizeof(startn) - 1;
1485                 }
1486                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1487                         start = 0;
1488                         linkset_name = sym_name + sizeof(stopn) - 1;
1489                 }
1490                 else
1491                         continue;
1492
1493                 for (i = 0; i < ef->nprogtab; i++) {
1494                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1495                                 startp = (Elf_Addr)ef->progtab[i].addr;
1496                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1497                                 break;
1498                         }
1499                 }
1500                 if (i == ef->nprogtab)
1501                         continue;
1502
1503                 sym->st_value = start ? startp : stopp;
1504                 sym->st_shndx = i;
1505         }
1506 }
1507
1508 static int
1509 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1510 {
1511         elf_file_t ef = (elf_file_t)lf;
1512         const Elf_Rel *rellim;
1513         const Elf_Rel *rel;
1514         const Elf_Rela *relalim;
1515         const Elf_Rela *rela;
1516         const Elf_Sym *sym;
1517         Elf_Addr base;
1518         int i;
1519         Elf_Size symidx;
1520
1521         link_elf_fix_link_set(ef);
1522
1523         /* Perform relocations without addend if there are any: */
1524         for (i = 0; i < ef->nreltab; i++) {
1525                 rel = ef->reltab[i].rel;
1526                 if (rel == NULL) {
1527                         link_elf_error(ef->lf.filename, "lost a reltab");
1528                         return (ENOEXEC);
1529                 }
1530                 rellim = rel + ef->reltab[i].nrel;
1531                 base = findbase(ef, ef->reltab[i].sec);
1532                 if (base == 0) {
1533                         link_elf_error(ef->lf.filename, "lost base for reltab");
1534                         return (ENOEXEC);
1535                 }
1536                 for ( ; rel < rellim; rel++) {
1537                         symidx = ELF_R_SYM(rel->r_info);
1538                         if (symidx >= ef->ddbsymcnt)
1539                                 continue;
1540                         sym = ef->ddbsymtab + symidx;
1541                         /* Only do local relocs */
1542                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1543                                 continue;
1544                         if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1545                             elf_is_ifunc_reloc(rel->r_info)) == ifuncs)
1546                                 elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1547                                     elf_obj_lookup);
1548                 }
1549         }
1550
1551         /* Perform relocations with addend if there are any: */
1552         for (i = 0; i < ef->nrelatab; i++) {
1553                 rela = ef->relatab[i].rela;
1554                 if (rela == NULL) {
1555                         link_elf_error(ef->lf.filename, "lost a relatab!");
1556                         return (ENOEXEC);
1557                 }
1558                 relalim = rela + ef->relatab[i].nrela;
1559                 base = findbase(ef, ef->relatab[i].sec);
1560                 if (base == 0) {
1561                         link_elf_error(ef->lf.filename, "lost base for reltab");
1562                         return (ENOEXEC);
1563                 }
1564                 for ( ; rela < relalim; rela++) {
1565                         symidx = ELF_R_SYM(rela->r_info);
1566                         if (symidx >= ef->ddbsymcnt)
1567                                 continue;
1568                         sym = ef->ddbsymtab + symidx;
1569                         /* Only do local relocs */
1570                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1571                                 continue;
1572                         if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1573                             elf_is_ifunc_reloc(rela->r_info)) == ifuncs)
1574                                 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1575                                     elf_obj_lookup);
1576                 }
1577         }
1578         return (0);
1579 }
1580
1581 static long
1582 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1583 {
1584     elf_file_t ef = (elf_file_t)lf;
1585
1586     *symtab = ef->ddbsymtab;
1587
1588     if (*symtab == NULL)
1589         return (0);
1590
1591     return (ef->ddbsymcnt);
1592 }
1593
1594 static long
1595 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1596 {
1597     elf_file_t ef = (elf_file_t)lf;
1598
1599     *strtab = ef->ddbstrtab;
1600
1601     if (*strtab == NULL)
1602         return (0);
1603
1604     return (ef->ddbstrcnt);
1605 }