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