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 <sys/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         { 0, 0 }
 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                                         error = ENOSPC;
 372                                         goto out;
 373                                 }
 374                                 memcpy(dpcpu, ef->progtab[pb].addr,
 375                                     ef->progtab[pb].size);
 376                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
 377                                 ef->progtab[pb].addr = dpcpu;
 378 #ifdef VIMAGE
 379                         } else if (ef->progtab[pb].name != NULL &&
 380                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 381                                 void *vnet_data;
 382
 383                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
 384                                 if (vnet_data == NULL) {
 385                                         error = ENOSPC;
 386                                         goto out;
 387                                 }
 388                                 memcpy(vnet_data, ef->progtab[pb].addr,
 389                                     ef->progtab[pb].size);
 390                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
 391                                 ef->progtab[pb].addr = vnet_data;
 392 #endif
 393                         } else if (ef->progtab[pb].name != NULL &&
 394                             !strcmp(ef->progtab[pb].name, ".ctors")) {
 395                                 lf->ctors_addr = ef->progtab[pb].addr;
 396                                 lf->ctors_size = shdr[i].sh_size;
 397                         }
 398
 399                         /* Update all symbol values with the offset. */
 400                         for (j = 0; j < ef->ddbsymcnt; j++) {
 401                                 es = &ef->ddbsymtab[j];
 402                                 if (es->st_shndx != i)
 403                                         continue;
 404                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 405                         }
 406                         pb++;
 407                         break;
 408                 case SHT_REL:
 409                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 410                                 break;
 411                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 412                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 413                         ef->reltab[rl].sec = shdr[i].sh_info;
 414                         rl++;
 415                         break;
 416                 case SHT_RELA:
 417                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 418                                 break;
 419                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 420                         ef->relatab[ra].nrela =
 421                             shdr[i].sh_size / sizeof(Elf_Rela);
 422                         ef->relatab[ra].sec = shdr[i].sh_info;
 423                         ra++;
 424                         break;
 425                 }
 426         }
 427         if (pb != ef->nprogtab) {
 428                 printf("%s: lost progbits\n", filename);
 429                 error = ENOEXEC;
 430                 goto out;
 431         }
 432         if (rl != ef->nreltab) {
 433                 printf("%s: lost reltab\n", filename);
 434                 error = ENOEXEC;
 435                 goto out;
 436         }
 437         if (ra != ef->nrelatab) {
 438                 printf("%s: lost relatab\n", filename);
 439                 error = ENOEXEC;
 440                 goto out;
 441         }
 442
 443         /* Local intra-module relocations */
 444         error = link_elf_reloc_local(lf, false);
 445         if (error != 0)
 446                 goto out;
 447         *result = lf;
 448         return (0);
 449
 450 out:
 451         /* preload not done this way */
 452         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 453         return (error);
 454 }
 455
 456 static void
 457 link_elf_invoke_ctors(caddr_t addr, size_t size)
 458 {
 459         void (**ctor)(void);
 460         size_t i, cnt;
 461
 462         if (addr == NULL || size == 0)
 463                 return;
 464         cnt = size / sizeof(*ctor);
 465         ctor = (void *)addr;
 466         for (i = 0; i < cnt; i++) {
 467                 if (ctor[i] != NULL)
 468                         (*ctor[i])();
 469         }
 470 }
 471
 472 static int
 473 link_elf_link_preload_finish(linker_file_t lf)
 474 {
 475         elf_file_t ef;
 476         int error;
 477
 478         ef = (elf_file_t)lf;
 479         error = relocate_file(ef);
 480         if (error)
 481                 return (error);
 482
 483         /* Notify MD code that a module is being loaded. */
 484         error = elf_cpu_load_file(lf);
 485         if (error)
 486                 return (error);
 487
 488 #if defined(__i386__) || defined(__amd64__)
 489         /* Now ifuncs. */
 490         error = link_elf_reloc_local(lf, true);
 491         if (error != 0)
 492                 return (error);
 493 #endif
 494
 495         /* Invoke .ctors */
 496         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 497         return (0);
 498 }
 499
 500 static int
 501 link_elf_load_file(linker_class_t cls, const char *filename,
 502     linker_file_t *result)
 503 {
 504         struct nameidata *nd;
 505         struct thread *td = curthread;  /* XXX */
 506         Elf_Ehdr *hdr;
 507         Elf_Shdr *shdr;
 508         Elf_Sym *es;
 509         int nbytes, i, j;
 510         vm_offset_t mapbase;
 511         size_t mapsize;
 512         int error = 0;
 513         ssize_t resid;
 514         int flags;
 515         elf_file_t ef;
 516         linker_file_t lf;
 517         int symtabindex;
 518         int symstrindex;
 519         int shstrindex;
 520         int nsym;
 521         int pb, rl, ra;
 522         int alignmask;
 523
 524         shdr = NULL;
 525         lf = NULL;
 526         mapsize = 0;
 527         hdr = NULL;
 528
 529         nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
 530         NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 531         flags = FREAD;
 532         error = vn_open(nd, &flags, 0, NULL);
 533         if (error) {
 534                 free(nd, M_TEMP);
 535                 return error;
 536         }
 537         NDFREE(nd, NDF_ONLY_PNBUF);
 538         if (nd->ni_vp->v_type != VREG) {
 539                 error = ENOEXEC;
 540                 goto out;
 541         }
 542 #ifdef MAC
 543         error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
 544         if (error) {
 545                 goto out;
 546         }
 547 #endif
 548
 549         /* Read the elf header from the file. */
 550         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 551         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
 552             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 553             &resid, td);
 554         if (error)
 555                 goto out;
 556         if (resid != 0){
 557                 error = ENOEXEC;
 558                 goto out;
 559         }
 560
 561         if (!IS_ELF(*hdr)) {
 562                 error = ENOEXEC;
 563                 goto out;
 564         }
 565
 566         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 567             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 568                 link_elf_error(filename, "Unsupported file layout");
 569                 error = ENOEXEC;
 570                 goto out;
 571         }
 572         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 573             || hdr->e_version != EV_CURRENT) {
 574                 link_elf_error(filename, "Unsupported file version");
 575                 error = ENOEXEC;
 576                 goto out;
 577         }
 578         if (hdr->e_type != ET_REL) {
 579                 error = ENOSYS;
 580                 goto out;
 581         }
 582         if (hdr->e_machine != ELF_TARG_MACH) {
 583                 link_elf_error(filename, "Unsupported machine");
 584                 error = ENOEXEC;
 585                 goto out;
 586         }
 587
 588         lf = linker_make_file(filename, &link_elf_class);
 589         if (!lf) {
 590                 error = ENOMEM;
 591                 goto out;
 592         }
 593         ef = (elf_file_t) lf;
 594         ef->nprogtab = 0;
 595         ef->e_shdr = 0;
 596         ef->nreltab = 0;
 597         ef->nrelatab = 0;
 598
 599         /* Allocate and read in the section header */
 600         nbytes = hdr->e_shnum * hdr->e_shentsize;
 601         if (nbytes == 0 || hdr->e_shoff == 0 ||
 602             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 603                 error = ENOEXEC;
 604                 goto out;
 605         }
 606         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 607         ef->e_shdr = shdr;
 608         error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
 609             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 610             NOCRED, &resid, td);
 611         if (error)
 612                 goto out;
 613         if (resid) {
 614                 error = ENOEXEC;
 615                 goto out;
 616         }
 617
 618         /* Scan the section header for information and table sizing. */
 619         nsym = 0;
 620         symtabindex = -1;
 621         symstrindex = -1;
 622         for (i = 0; i < hdr->e_shnum; i++) {
 623                 if (shdr[i].sh_size == 0)
 624                         continue;
 625                 switch (shdr[i].sh_type) {
 626                 case SHT_PROGBITS:
 627                 case SHT_NOBITS:
 628 #ifdef __amd64__
 629                 case SHT_X86_64_UNWIND:
 630 #endif
 631                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 632                                 break;
 633                         ef->nprogtab++;
 634                         break;
 635                 case SHT_SYMTAB:
 636                         nsym++;
 637                         symtabindex = i;
 638                         symstrindex = shdr[i].sh_link;
 639                         break;
 640                 case SHT_REL:
 641                         /*
 642                          * Ignore relocation tables for unallocated
 643                          * sections.
 644                          */
 645                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 646                                 break;
 647                         ef->nreltab++;
 648                         break;
 649                 case SHT_RELA:
 650                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 651                                 break;
 652                         ef->nrelatab++;
 653                         break;
 654                 case SHT_STRTAB:
 655                         break;
 656                 }
 657         }
 658         if (ef->nprogtab == 0) {
 659                 link_elf_error(filename, "file has no contents");
 660                 error = ENOEXEC;
 661                 goto out;
 662         }
 663         if (nsym != 1) {
 664                 /* Only allow one symbol table for now */
 665                 link_elf_error(filename,
 666                     "file must have exactly one symbol table");
 667                 error = ENOEXEC;
 668                 goto out;
 669         }
 670         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 671             shdr[symstrindex].sh_type != SHT_STRTAB) {
 672                 link_elf_error(filename, "file has invalid symbol strings");
 673                 error = ENOEXEC;
 674                 goto out;
 675         }
 676
 677         /* Allocate space for tracking the load chunks */
 678         if (ef->nprogtab != 0)
 679                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 680                     M_LINKER, M_WAITOK | M_ZERO);
 681         if (ef->nreltab != 0)
 682                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 683                     M_LINKER, M_WAITOK | M_ZERO);
 684         if (ef->nrelatab != 0)
 685                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 686                     M_LINKER, M_WAITOK | M_ZERO);
 687
 688         if (symtabindex == -1) {
 689                 link_elf_error(filename, "lost symbol table index");
 690                 error = ENOEXEC;
 691                 goto out;
 692         }
 693         /* Allocate space for and load the symbol table */
 694         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 695         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 696         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 697             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 698             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 699             &resid, td);
 700         if (error)
 701                 goto out;
 702         if (resid != 0){
 703                 error = EINVAL;
 704                 goto out;
 705         }
 706
 707         if (symstrindex == -1) {
 708                 link_elf_error(filename, "lost symbol string index");
 709                 error = ENOEXEC;
 710                 goto out;
 711         }
 712         /* Allocate space for and load the symbol strings */
 713         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 714         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 715         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 716             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 717             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 718             &resid, td);
 719         if (error)
 720                 goto out;
 721         if (resid != 0){
 722                 error = EINVAL;
 723                 goto out;
 724         }
 725
 726         /* Do we have a string table for the section names?  */
 727         shstrindex = -1;
 728         if (hdr->e_shstrndx != 0 &&
 729             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 730                 shstrindex = hdr->e_shstrndx;
 731                 ef->shstrcnt = shdr[shstrindex].sh_size;
 732                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 733                     M_WAITOK);
 734                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 735                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 736                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 737                     &resid, td);
 738                 if (error)
 739                         goto out;
 740                 if (resid != 0){
 741                         error = EINVAL;
 742                         goto out;
 743                 }
 744         }
 745
 746         /* Size up code/data(progbits) and bss(nobits). */
 747         alignmask = 0;
 748         for (i = 0; i < hdr->e_shnum; i++) {
 749                 if (shdr[i].sh_size == 0)
 750                         continue;
 751                 switch (shdr[i].sh_type) {
 752                 case SHT_PROGBITS:
 753                 case SHT_NOBITS:
 754 #ifdef __amd64__
 755                 case SHT_X86_64_UNWIND:
 756 #endif
 757                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 758                                 break;
 759                         alignmask = shdr[i].sh_addralign - 1;
 760                         mapsize += alignmask;
 761                         mapsize &= ~alignmask;
 762                         mapsize += shdr[i].sh_size;
 763                         break;
 764                 }
 765         }
 766
 767         /*
 768          * We know how much space we need for the text/data/bss/etc.
 769          * This stuff needs to be in a single chunk so that profiling etc
 770          * can get the bounds and gdb can associate offsets with modules
 771          */
 772         ef->object = vm_object_allocate(OBJT_DEFAULT,
 773             round_page(mapsize) >> PAGE_SHIFT);
 774         if (ef->object == NULL) {
 775                 error = ENOMEM;
 776                 goto out;
 777         }
 778         ef->address = (caddr_t) vm_map_min(kernel_map);
 779
 780         /*
 781          * In order to satisfy amd64's architectural requirements on the
 782          * location of code and data in the kernel's address space, request a
 783          * mapping that is above the kernel.
 784          */
 785 #ifdef __amd64__
 786         mapbase = KERNBASE;
 787 #else
 788         mapbase = VM_MIN_KERNEL_ADDRESS;
 789 #endif
 790         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 791             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 792             VM_PROT_ALL, 0);
 793         if (error) {
 794                 vm_object_deallocate(ef->object);
 795                 ef->object = 0;
 796                 goto out;
 797         }
 798
 799         /* Wire the pages */
 800         error = vm_map_wire(kernel_map, mapbase,
 801             mapbase + round_page(mapsize),
 802             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 803         if (error != KERN_SUCCESS) {
 804                 error = ENOMEM;
 805                 goto out;
 806         }
 807
 808         /* Inform the kld system about the situation */
 809         lf->address = ef->address = (caddr_t)mapbase;
 810         lf->size = mapsize;
 811
 812         /*
 813          * Now load code/data(progbits), zero bss(nobits), allocate space for
 814          * and load relocs
 815          */
 816         pb = 0;
 817         rl = 0;
 818         ra = 0;
 819         alignmask = 0;
 820         for (i = 0; i < hdr->e_shnum; i++) {
 821                 if (shdr[i].sh_size == 0)
 822                         continue;
 823                 switch (shdr[i].sh_type) {
 824                 case SHT_PROGBITS:
 825                 case SHT_NOBITS:
 826 #ifdef __amd64__
 827                 case SHT_X86_64_UNWIND:
 828 #endif
 829                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 830                                 break;
 831                         alignmask = shdr[i].sh_addralign - 1;
 832                         mapbase += alignmask;
 833                         mapbase &= ~alignmask;
 834                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 835                                 ef->progtab[pb].name =
 836                                     ef->shstrtab + shdr[i].sh_name;
 837                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 838                                         lf->ctors_addr = (caddr_t)mapbase;
 839                                         lf->ctors_size = shdr[i].sh_size;
 840                                 }
 841                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 842                                 ef->progtab[pb].name = "<<PROGBITS>>";
 843 #ifdef __amd64__
 844                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 845                                 ef->progtab[pb].name = "<<UNWIND>>";
 846 #endif
 847                         else
 848                                 ef->progtab[pb].name = "<<NOBITS>>";
 849                         if (ef->progtab[pb].name != NULL &&
 850                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 851                                 ef->progtab[pb].addr =
 852                                     dpcpu_alloc(shdr[i].sh_size);
 853 #ifdef VIMAGE
 854                         else if (ef->progtab[pb].name != NULL &&
 855                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 856                                 ef->progtab[pb].addr =
 857                                     vnet_data_alloc(shdr[i].sh_size);
 858 #endif
 859                         else
 860                                 ef->progtab[pb].addr =
 861                                     (void *)(uintptr_t)mapbase;
 862                         if (ef->progtab[pb].addr == NULL) {
 863                                 error = ENOSPC;
 864                                 goto out;
 865                         }
 866                         ef->progtab[pb].size = shdr[i].sh_size;
 867                         ef->progtab[pb].sec = i;
 868                         if (shdr[i].sh_type == SHT_PROGBITS
 869 #ifdef __amd64__
 870                             || shdr[i].sh_type == SHT_X86_64_UNWIND
 871 #endif
 872                             ) {
 873                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
 874                                     ef->progtab[pb].addr,
 875                                     shdr[i].sh_size, shdr[i].sh_offset,
 876                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 877                                     NOCRED, &resid, td);
 878                                 if (error)
 879                                         goto out;
 880                                 if (resid != 0){
 881                                         error = EINVAL;
 882                                         goto out;
 883                                 }
 884                                 /* Initialize the per-cpu or vnet area. */
 885                                 if (ef->progtab[pb].addr != (void *)mapbase &&
 886                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 887                                         dpcpu_copy(ef->progtab[pb].addr,
 888                                             shdr[i].sh_size);
 889 #ifdef VIMAGE
 890                                 else if (ef->progtab[pb].addr !=
 891                                     (void *)mapbase &&
 892                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 893                                         vnet_data_copy(ef->progtab[pb].addr,
 894                                             shdr[i].sh_size);
 895 #endif
 896                         } else
 897                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 898
 899                         /* Update all symbol values with the offset. */
 900                         for (j = 0; j < ef->ddbsymcnt; j++) {
 901                                 es = &ef->ddbsymtab[j];
 902                                 if (es->st_shndx != i)
 903                                         continue;
 904                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 905                         }
 906                         mapbase += shdr[i].sh_size;
 907                         pb++;
 908                         break;
 909                 case SHT_REL:
 910                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 911                                 break;
 912                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 913                             M_WAITOK);
 914                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 915                         ef->reltab[rl].sec = shdr[i].sh_info;
 916                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 917                             (void *)ef->reltab[rl].rel,
 918                             shdr[i].sh_size, shdr[i].sh_offset,
 919                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 920                             &resid, td);
 921                         if (error)
 922                                 goto out;
 923                         if (resid != 0){
 924                                 error = EINVAL;
 925                                 goto out;
 926                         }
 927                         rl++;
 928                         break;
 929                 case SHT_RELA:
 930                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 931                                 break;
 932                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 933                             M_WAITOK);
 934                         ef->relatab[ra].nrela =
 935                             shdr[i].sh_size / sizeof(Elf_Rela);
 936                         ef->relatab[ra].sec = shdr[i].sh_info;
 937                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 938                             (void *)ef->relatab[ra].rela,
 939                             shdr[i].sh_size, shdr[i].sh_offset,
 940                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 941                             &resid, td);
 942                         if (error)
 943                                 goto out;
 944                         if (resid != 0){
 945                                 error = EINVAL;
 946                                 goto out;
 947                         }
 948                         ra++;
 949                         break;
 950                 }
 951         }
 952         if (pb != ef->nprogtab) {
 953                 link_elf_error(filename, "lost progbits");
 954                 error = ENOEXEC;
 955                 goto out;
 956         }
 957         if (rl != ef->nreltab) {
 958                 link_elf_error(filename, "lost reltab");
 959                 error = ENOEXEC;
 960                 goto out;
 961         }
 962         if (ra != ef->nrelatab) {
 963                 link_elf_error(filename, "lost relatab");
 964                 error = ENOEXEC;
 965                 goto out;
 966         }
 967         if (mapbase != (vm_offset_t)ef->address + mapsize) {
 968                 printf(
 969                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 970                     filename != NULL ? filename : "<none>",
 971                     (u_long)mapbase, ef->address, (u_long)mapsize,
 972                     (u_long)(vm_offset_t)ef->address + mapsize);
 973                 error = ENOMEM;
 974                 goto out;
 975         }
 976
 977         /* Local intra-module relocations */
 978         error = link_elf_reloc_local(lf, false);
 979         if (error != 0)
 980                 goto out;
 981
 982         /* Pull in dependencies */
 983         VOP_UNLOCK(nd->ni_vp, 0);
 984         error = linker_load_dependencies(lf);
 985         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
 986         if (error)
 987                 goto out;
 988
 989         /* External relocations */
 990         error = relocate_file(ef);
 991         if (error)
 992                 goto out;
 993
 994         /* Notify MD code that a module is being loaded. */
 995         error = elf_cpu_load_file(lf);
 996         if (error)
 997                 goto out;
 998
 999 #if defined(__i386__) || defined(__amd64__)
1000         /* Now ifuncs. */
1001         error = link_elf_reloc_local(lf, true);
1002         if (error != 0)
1003                 goto out;
1004 #endif
1005
1006         /* Invoke .ctors */
1007         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
1008
1009         *result = lf;
1010
1011 out:
1012         VOP_UNLOCK(nd->ni_vp, 0);
1013         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1014         free(nd, M_TEMP);
1015         if (error && lf)
1016                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1017         free(hdr, M_LINKER);
1018
1019         return error;
1020 }
1021
1022 static void
1023 link_elf_unload_file(linker_file_t file)
1024 {
1025         elf_file_t ef = (elf_file_t) file;
1026         u_int i;
1027
1028         /* Notify MD code that a module is being unloaded. */
1029         elf_cpu_unload_file(file);
1030
1031         if (ef->progtab) {
1032                 for (i = 0; i < ef->nprogtab; i++) {
1033                         if (ef->progtab[i].size == 0)
1034                                 continue;
1035                         if (ef->progtab[i].name == NULL)
1036                                 continue;
1037                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1038                                 dpcpu_free(ef->progtab[i].addr,
1039                                     ef->progtab[i].size);
1040 #ifdef VIMAGE
1041                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1042                                 vnet_data_free(ef->progtab[i].addr,
1043                                     ef->progtab[i].size);
1044 #endif
1045                 }
1046         }
1047         if (ef->preloaded) {
1048                 free(ef->reltab, M_LINKER);
1049                 free(ef->relatab, M_LINKER);
1050                 free(ef->progtab, M_LINKER);
1051                 free(ef->ctftab, M_LINKER);
1052                 free(ef->ctfoff, M_LINKER);
1053                 free(ef->typoff, M_LINKER);
1054                 if (file->pathname != NULL)
1055                         preload_delete_name(file->pathname);
1056                 return;
1057         }
1058
1059         for (i = 0; i < ef->nreltab; i++)
1060                 free(ef->reltab[i].rel, M_LINKER);
1061         for (i = 0; i < ef->nrelatab; i++)
1062                 free(ef->relatab[i].rela, M_LINKER);
1063         free(ef->reltab, M_LINKER);
1064         free(ef->relatab, M_LINKER);
1065         free(ef->progtab, M_LINKER);
1066
1067         if (ef->object) {
1068                 vm_map_remove(kernel_map, (vm_offset_t) ef->address,
1069                     (vm_offset_t) ef->address +
1070                     (ef->object->size << PAGE_SHIFT));
1071         }
1072         free(ef->e_shdr, M_LINKER);
1073         free(ef->ddbsymtab, M_LINKER);
1074         free(ef->ddbstrtab, M_LINKER);
1075         free(ef->shstrtab, M_LINKER);
1076         free(ef->ctftab, M_LINKER);
1077         free(ef->ctfoff, M_LINKER);
1078         free(ef->typoff, M_LINKER);
1079 }
1080
1081 static const char *
1082 symbol_name(elf_file_t ef, Elf_Size r_info)
1083 {
1084         const Elf_Sym *ref;
1085
1086         if (ELF_R_SYM(r_info)) {
1087                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1088                 return ef->ddbstrtab + ref->st_name;
1089         } else
1090                 return NULL;
1091 }
1092
1093 static Elf_Addr
1094 findbase(elf_file_t ef, int sec)
1095 {
1096         int i;
1097         Elf_Addr base = 0;
1098
1099         for (i = 0; i < ef->nprogtab; i++) {
1100                 if (sec == ef->progtab[i].sec) {
1101                         base = (Elf_Addr)ef->progtab[i].addr;
1102                         break;
1103                 }
1104         }
1105         return base;
1106 }
1107
1108 static int
1109 relocate_file(elf_file_t ef)
1110 {
1111         const Elf_Rel *rellim;
1112         const Elf_Rel *rel;
1113         const Elf_Rela *relalim;
1114         const Elf_Rela *rela;
1115         const char *symname;
1116         const Elf_Sym *sym;
1117         int i;
1118         Elf_Size symidx;
1119         Elf_Addr base;
1120
1121
1122         /* Perform relocations without addend if there are any: */
1123         for (i = 0; i < ef->nreltab; i++) {
1124                 rel = ef->reltab[i].rel;
1125                 if (rel == NULL) {
1126                         link_elf_error(ef->lf.filename, "lost a reltab!");
1127                         return (ENOEXEC);
1128                 }
1129                 rellim = rel + ef->reltab[i].nrel;
1130                 base = findbase(ef, ef->reltab[i].sec);
1131                 if (base == 0) {
1132                         link_elf_error(ef->lf.filename, "lost base for reltab");
1133                         return (ENOEXEC);
1134                 }
1135                 for ( ; rel < rellim; rel++) {
1136                         symidx = ELF_R_SYM(rel->r_info);
1137                         if (symidx >= ef->ddbsymcnt)
1138                                 continue;
1139                         sym = ef->ddbsymtab + symidx;
1140                         /* Local relocs are already done */
1141                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1142                                 continue;
1143                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1144                             elf_obj_lookup)) {
1145                                 symname = symbol_name(ef, rel->r_info);
1146                                 printf("link_elf_obj: symbol %s undefined\n",
1147                                     symname);
1148                                 return (ENOENT);
1149                         }
1150                 }
1151         }
1152
1153         /* Perform relocations with addend if there are any: */
1154         for (i = 0; i < ef->nrelatab; i++) {
1155                 rela = ef->relatab[i].rela;
1156                 if (rela == NULL) {
1157                         link_elf_error(ef->lf.filename, "lost a relatab!");
1158                         return (ENOEXEC);
1159                 }
1160                 relalim = rela + ef->relatab[i].nrela;
1161                 base = findbase(ef, ef->relatab[i].sec);
1162                 if (base == 0) {
1163                         link_elf_error(ef->lf.filename,
1164                             "lost base for relatab");
1165                         return (ENOEXEC);
1166                 }
1167                 for ( ; rela < relalim; rela++) {
1168                         symidx = ELF_R_SYM(rela->r_info);
1169                         if (symidx >= ef->ddbsymcnt)
1170                                 continue;
1171                         sym = ef->ddbsymtab + symidx;
1172                         /* Local relocs are already done */
1173                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1174                                 continue;
1175                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1176                             elf_obj_lookup)) {
1177                                 symname = symbol_name(ef, rela->r_info);
1178                                 printf("link_elf_obj: symbol %s undefined\n",
1179                                     symname);
1180                                 return (ENOENT);
1181                         }
1182                 }
1183         }
1184
1185         /*
1186          * Only clean SHN_FBSD_CACHED for successful return.  If we
1187          * modified symbol table for the object but found an
1188          * unresolved symbol, there is no reason to roll back.
1189          */
1190         elf_obj_cleanup_globals_cache(ef);
1191
1192         return (0);
1193 }
1194
1195 static int
1196 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1197 {
1198         elf_file_t ef = (elf_file_t) lf;
1199         const Elf_Sym *symp;
1200         const char *strp;
1201         int i;
1202
1203         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1204                 strp = ef->ddbstrtab + symp->st_name;
1205                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1206                         *sym = (c_linker_sym_t) symp;
1207                         return 0;
1208                 }
1209         }
1210         return ENOENT;
1211 }
1212
1213 static int
1214 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1215     linker_symval_t *symval)
1216 {
1217         elf_file_t ef;
1218         const Elf_Sym *es;
1219         caddr_t val;
1220
1221         ef = (elf_file_t) lf;
1222         es = (const Elf_Sym*) sym;
1223         val = (caddr_t)es->st_value;
1224         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1225                 symval->name = ef->ddbstrtab + es->st_name;
1226                 val = (caddr_t)es->st_value;
1227                 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1228                         val = ((caddr_t (*)(void))val)();
1229                 symval->value = val;
1230                 symval->size = es->st_size;
1231                 return 0;
1232         }
1233         return ENOENT;
1234 }
1235
1236 static int
1237 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1238     c_linker_sym_t *sym, long *diffp)
1239 {
1240         elf_file_t ef = (elf_file_t) lf;
1241         u_long off = (uintptr_t) (void *) value;
1242         u_long diff = off;
1243         u_long st_value;
1244         const Elf_Sym *es;
1245         const Elf_Sym *best = NULL;
1246         int i;
1247
1248         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1249                 if (es->st_name == 0)
1250                         continue;
1251                 st_value = es->st_value;
1252                 if (off >= st_value) {
1253                         if (off - st_value < diff) {
1254                                 diff = off - st_value;
1255                                 best = es;
1256                                 if (diff == 0)
1257                                         break;
1258                         } else if (off - st_value == diff) {
1259                                 best = es;
1260                         }
1261                 }
1262         }
1263         if (best == NULL)
1264                 *diffp = off;
1265         else
1266                 *diffp = diff;
1267         *sym = (c_linker_sym_t) best;
1268
1269         return 0;
1270 }
1271
1272 /*
1273  * Look up a linker set on an ELF system.
1274  */
1275 static int
1276 link_elf_lookup_set(linker_file_t lf, const char *name,
1277     void ***startp, void ***stopp, int *countp)
1278 {
1279         elf_file_t ef = (elf_file_t)lf;
1280         void **start, **stop;
1281         int i, count;
1282
1283         /* Relative to section number */
1284         for (i = 0; i < ef->nprogtab; i++) {
1285                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1286                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1287                         start  = (void **)ef->progtab[i].addr;
1288                         stop = (void **)((char *)ef->progtab[i].addr +
1289                             ef->progtab[i].size);
1290                         count = stop - start;
1291                         if (startp)
1292                                 *startp = start;
1293                         if (stopp)
1294                                 *stopp = stop;
1295                         if (countp)
1296                                 *countp = count;
1297                         return (0);
1298                 }
1299         }
1300         return (ESRCH);
1301 }
1302
1303 static int
1304 link_elf_each_function_name(linker_file_t file,
1305     int (*callback)(const char *, void *), void *opaque)
1306 {
1307         elf_file_t ef = (elf_file_t)file;
1308         const Elf_Sym *symp;
1309         int i, error;
1310
1311         /* Exhaustive search */
1312         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1313                 if (symp->st_value != 0 &&
1314                     (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1315                     ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1316                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1317                         if (error)
1318                                 return (error);
1319                 }
1320         }
1321         return (0);
1322 }
1323
1324 static int
1325 link_elf_each_function_nameval(linker_file_t file,
1326     linker_function_nameval_callback_t callback, void *opaque)
1327 {
1328         linker_symval_t symval;
1329         elf_file_t ef = (elf_file_t)file;
1330         const Elf_Sym* symp;
1331         int i, error;
1332
1333         /* Exhaustive search */
1334         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1335                 if (symp->st_value != 0 &&
1336                     (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1337                     ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1338                         error = link_elf_symbol_values(file,
1339                             (c_linker_sym_t)symp, &symval);
1340                         if (error)
1341                                 return (error);
1342                         error = callback(file, i, &symval, opaque);
1343                         if (error)
1344                                 return (error);
1345                 }
1346         }
1347         return (0);
1348 }
1349
1350 static void
1351 elf_obj_cleanup_globals_cache(elf_file_t ef)
1352 {
1353         Elf_Sym *sym;
1354         Elf_Size i;
1355
1356         for (i = 0; i < ef->ddbsymcnt; i++) {
1357                 sym = ef->ddbsymtab + i;
1358                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1359                         sym->st_shndx = SHN_UNDEF;
1360                         sym->st_value = 0;
1361                 }
1362         }
1363 }
1364
1365 /*
1366  * Symbol lookup function that can be used when the symbol index is known (ie
1367  * in relocations). It uses the symbol index instead of doing a fully fledged
1368  * hash table based lookup when such is valid. For example for local symbols.
1369  * This is not only more efficient, it's also more correct. It's not always
1370  * the case that the symbol can be found through the hash table.
1371  */
1372 static int
1373 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1374 {
1375         elf_file_t ef = (elf_file_t)lf;
1376         Elf_Sym *sym;
1377         const char *symbol;
1378         Elf_Addr res1;
1379
1380         /* Don't even try to lookup the symbol if the index is bogus. */
1381         if (symidx >= ef->ddbsymcnt) {
1382                 *res = 0;
1383                 return (EINVAL);
1384         }
1385
1386         sym = ef->ddbsymtab + symidx;
1387
1388         /* Quick answer if there is a definition included. */
1389         if (sym->st_shndx != SHN_UNDEF) {
1390                 res1 = (Elf_Addr)sym->st_value;
1391                 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1392                         res1 = ((Elf_Addr (*)(void))res1)();
1393                 *res = res1;
1394                 return (0);
1395         }
1396
1397         /* If we get here, then it is undefined and needs a lookup. */
1398         switch (ELF_ST_BIND(sym->st_info)) {
1399         case STB_LOCAL:
1400                 /* Local, but undefined? huh? */
1401                 *res = 0;
1402                 return (EINVAL);
1403
1404         case STB_GLOBAL:
1405         case STB_WEAK:
1406                 /* Relative to Data or Function name */
1407                 symbol = ef->ddbstrtab + sym->st_name;
1408
1409                 /* Force a lookup failure if the symbol name is bogus. */
1410                 if (*symbol == 0) {
1411                         *res = 0;
1412                         return (EINVAL);
1413                 }
1414                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1415
1416                 /*
1417                  * Cache global lookups during module relocation. The failure
1418                  * case is particularly expensive for callers, who must scan
1419                  * through the entire globals table doing strcmp(). Cache to
1420                  * avoid doing such work repeatedly.
1421                  *
1422                  * After relocation is complete, undefined globals will be
1423                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1424                  * above.
1425                  */
1426                 if (res1 != 0) {
1427                         sym->st_shndx = SHN_FBSD_CACHED;
1428                         sym->st_value = res1;
1429                         *res = res1;
1430                         return (0);
1431                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1432                         sym->st_value = 0;
1433                         *res = 0;
1434                         return (0);
1435                 }
1436                 return (EINVAL);
1437
1438         default:
1439                 return (EINVAL);
1440         }
1441 }
1442
1443 static void
1444 link_elf_fix_link_set(elf_file_t ef)
1445 {
1446         static const char startn[] = "__start_";
1447         static const char stopn[] = "__stop_";
1448         Elf_Sym *sym;
1449         const char *sym_name, *linkset_name;
1450         Elf_Addr startp, stopp;
1451         Elf_Size symidx;
1452         int start, i;
1453
1454         startp = stopp = 0;
1455         for (symidx = 1 /* zero entry is special */;
1456                 symidx < ef->ddbsymcnt; symidx++) {
1457                 sym = ef->ddbsymtab + symidx;
1458                 if (sym->st_shndx != SHN_UNDEF)
1459                         continue;
1460
1461                 sym_name = ef->ddbstrtab + sym->st_name;
1462                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1463                         start = 1;
1464                         linkset_name = sym_name + sizeof(startn) - 1;
1465                 }
1466                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1467                         start = 0;
1468                         linkset_name = sym_name + sizeof(stopn) - 1;
1469                 }
1470                 else
1471                         continue;
1472
1473                 for (i = 0; i < ef->nprogtab; i++) {
1474                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1475                                 startp = (Elf_Addr)ef->progtab[i].addr;
1476                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1477                                 break;
1478                         }
1479                 }
1480                 if (i == ef->nprogtab)
1481                         continue;
1482
1483                 sym->st_value = start ? startp : stopp;
1484                 sym->st_shndx = i;
1485         }
1486 }
1487
1488 static int
1489 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1490 {
1491         elf_file_t ef = (elf_file_t)lf;
1492         const Elf_Rel *rellim;
1493         const Elf_Rel *rel;
1494         const Elf_Rela *relalim;
1495         const Elf_Rela *rela;
1496         const Elf_Sym *sym;
1497         Elf_Addr base;
1498         int i;
1499         Elf_Size symidx;
1500
1501         link_elf_fix_link_set(ef);
1502
1503         /* Perform relocations without addend if there are any: */
1504         for (i = 0; i < ef->nreltab; i++) {
1505                 rel = ef->reltab[i].rel;
1506                 if (rel == NULL) {
1507                         link_elf_error(ef->lf.filename, "lost a reltab");
1508                         return (ENOEXEC);
1509                 }
1510                 rellim = rel + ef->reltab[i].nrel;
1511                 base = findbase(ef, ef->reltab[i].sec);
1512                 if (base == 0) {
1513                         link_elf_error(ef->lf.filename, "lost base for reltab");
1514                         return (ENOEXEC);
1515                 }
1516                 for ( ; rel < rellim; rel++) {
1517                         symidx = ELF_R_SYM(rel->r_info);
1518                         if (symidx >= ef->ddbsymcnt)
1519                                 continue;
1520                         sym = ef->ddbsymtab + symidx;
1521                         /* Only do local relocs */
1522                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1523                                 continue;
1524                         if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1525                             elf_is_ifunc_reloc(rel->r_info)) == ifuncs)
1526                                 elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1527                                     elf_obj_lookup);
1528                 }
1529         }
1530
1531         /* Perform relocations with addend if there are any: */
1532         for (i = 0; i < ef->nrelatab; i++) {
1533                 rela = ef->relatab[i].rela;
1534                 if (rela == NULL) {
1535                         link_elf_error(ef->lf.filename, "lost a relatab!");
1536                         return (ENOEXEC);
1537                 }
1538                 relalim = rela + ef->relatab[i].nrela;
1539                 base = findbase(ef, ef->relatab[i].sec);
1540                 if (base == 0) {
1541                         link_elf_error(ef->lf.filename, "lost base for reltab");
1542                         return (ENOEXEC);
1543                 }
1544                 for ( ; rela < relalim; rela++) {
1545                         symidx = ELF_R_SYM(rela->r_info);
1546                         if (symidx >= ef->ddbsymcnt)
1547                                 continue;
1548                         sym = ef->ddbsymtab + symidx;
1549                         /* Only do local relocs */
1550                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1551                                 continue;
1552                         if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1553                             elf_is_ifunc_reloc(rela->r_info)) == ifuncs)
1554                                 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1555                                     elf_obj_lookup);
1556                 }
1557         }
1558         return (0);
1559 }
1560
1561 static long
1562 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1563 {
1564     elf_file_t ef = (elf_file_t)lf;
1565
1566     *symtab = ef->ddbsymtab;
1567
1568     if (*symtab == NULL)
1569         return (0);
1570
1571     return (ef->ddbsymcnt);
1572 }
1573
1574 static long
1575 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1576 {
1577     elf_file_t ef = (elf_file_t)lf;
1578
1579     *strtab = ef->ddbstrtab;
1580
1581     if (*strtab == NULL)
1582         return (0);
1583
1584     return (ef->ddbstrcnt);
1585 }