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, 0);
 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, "file has no valid symbol table");
 660                 error = ENOEXEC;
 661                 goto out;
 662         }
 663         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 664             shdr[symstrindex].sh_type != SHT_STRTAB) {
 665                 link_elf_error(filename, "file has invalid symbol strings");
 666                 error = ENOEXEC;
 667                 goto out;
 668         }
 669
 670         /* Allocate space for tracking the load chunks */
 671         if (ef->nprogtab != 0)
 672                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 673                     M_LINKER, M_WAITOK | M_ZERO);
 674         if (ef->nreltab != 0)
 675                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 676                     M_LINKER, M_WAITOK | M_ZERO);
 677         if (ef->nrelatab != 0)
 678                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 679                     M_LINKER, M_WAITOK | M_ZERO);
 680
 681         if (symtabindex == -1) {
 682                 link_elf_error(filename, "lost symbol table index");
 683                 error = ENOEXEC;
 684                 goto out;
 685         }
 686         /* Allocate space for and load the symbol table */
 687         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 688         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 689         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 690             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 691             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 692             &resid, td);
 693         if (error)
 694                 goto out;
 695         if (resid != 0){
 696                 error = EINVAL;
 697                 goto out;
 698         }
 699
 700         if (symstrindex == -1) {
 701                 link_elf_error(filename, "lost symbol string index");
 702                 error = ENOEXEC;
 703                 goto out;
 704         }
 705         /* Allocate space for and load the symbol strings */
 706         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 707         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 708         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 709             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 710             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 711             &resid, td);
 712         if (error)
 713                 goto out;
 714         if (resid != 0){
 715                 error = EINVAL;
 716                 goto out;
 717         }
 718
 719         /* Do we have a string table for the section names?  */
 720         shstrindex = -1;
 721         if (hdr->e_shstrndx != 0 &&
 722             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 723                 shstrindex = hdr->e_shstrndx;
 724                 ef->shstrcnt = shdr[shstrindex].sh_size;
 725                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 726                     M_WAITOK);
 727                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 728                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 729                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 730                     &resid, td);
 731                 if (error)
 732                         goto out;
 733                 if (resid != 0){
 734                         error = EINVAL;
 735                         goto out;
 736                 }
 737         }
 738
 739         /* Size up code/data(progbits) and bss(nobits). */
 740         alignmask = 0;
 741         for (i = 0; i < hdr->e_shnum; i++) {
 742                 if (shdr[i].sh_size == 0)
 743                         continue;
 744                 switch (shdr[i].sh_type) {
 745                 case SHT_PROGBITS:
 746                 case SHT_NOBITS:
 747 #ifdef __amd64__
 748                 case SHT_X86_64_UNWIND:
 749 #endif
 750                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 751                                 break;
 752                         alignmask = shdr[i].sh_addralign - 1;
 753                         mapsize += alignmask;
 754                         mapsize &= ~alignmask;
 755                         mapsize += shdr[i].sh_size;
 756                         break;
 757                 }
 758         }
 759
 760         /*
 761          * We know how much space we need for the text/data/bss/etc.
 762          * This stuff needs to be in a single chunk so that profiling etc
 763          * can get the bounds and gdb can associate offsets with modules
 764          */
 765         ef->object = vm_object_allocate(OBJT_DEFAULT,
 766             round_page(mapsize) >> PAGE_SHIFT);
 767         if (ef->object == NULL) {
 768                 error = ENOMEM;
 769                 goto out;
 770         }
 771         ef->address = (caddr_t) vm_map_min(kernel_map);
 772
 773         /*
 774          * In order to satisfy amd64's architectural requirements on the
 775          * location of code and data in the kernel's address space, request a
 776          * mapping that is above the kernel.
 777          */
 778 #ifdef __amd64__
 779         mapbase = KERNBASE;
 780 #else
 781         mapbase = VM_MIN_KERNEL_ADDRESS;
 782 #endif
 783         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 784             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 785             VM_PROT_ALL, 0);
 786         if (error) {
 787                 vm_object_deallocate(ef->object);
 788                 ef->object = 0;
 789                 goto out;
 790         }
 791
 792         /* Wire the pages */
 793         error = vm_map_wire(kernel_map, mapbase,
 794             mapbase + round_page(mapsize),
 795             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 796         if (error != KERN_SUCCESS) {
 797                 error = ENOMEM;
 798                 goto out;
 799         }
 800
 801         /* Inform the kld system about the situation */
 802         lf->address = ef->address = (caddr_t)mapbase;
 803         lf->size = mapsize;
 804
 805         /*
 806          * Now load code/data(progbits), zero bss(nobits), allocate space for
 807          * and load relocs
 808          */
 809         pb = 0;
 810         rl = 0;
 811         ra = 0;
 812         alignmask = 0;
 813         for (i = 0; i < hdr->e_shnum; i++) {
 814                 if (shdr[i].sh_size == 0)
 815                         continue;
 816                 switch (shdr[i].sh_type) {
 817                 case SHT_PROGBITS:
 818                 case SHT_NOBITS:
 819 #ifdef __amd64__
 820                 case SHT_X86_64_UNWIND:
 821 #endif
 822                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 823                                 break;
 824                         alignmask = shdr[i].sh_addralign - 1;
 825                         mapbase += alignmask;
 826                         mapbase &= ~alignmask;
 827                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 828                                 ef->progtab[pb].name =
 829                                     ef->shstrtab + shdr[i].sh_name;
 830                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 831                                         lf->ctors_addr = (caddr_t)mapbase;
 832                                         lf->ctors_size = shdr[i].sh_size;
 833                                 }
 834                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 835                                 ef->progtab[pb].name = "<<PROGBITS>>";
 836 #ifdef __amd64__
 837                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 838                                 ef->progtab[pb].name = "<<UNWIND>>";
 839 #endif
 840                         else
 841                                 ef->progtab[pb].name = "<<NOBITS>>";
 842                         if (ef->progtab[pb].name != NULL &&
 843                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 844                                 ef->progtab[pb].addr =
 845                                     dpcpu_alloc(shdr[i].sh_size);
 846 #ifdef VIMAGE
 847                         else if (ef->progtab[pb].name != NULL &&
 848                             !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 849                                 ef->progtab[pb].addr =
 850                                     vnet_data_alloc(shdr[i].sh_size);
 851 #endif
 852                         else
 853                                 ef->progtab[pb].addr =
 854                                     (void *)(uintptr_t)mapbase;
 855                         if (ef->progtab[pb].addr == NULL) {
 856                                 error = ENOSPC;
 857                                 goto out;
 858                         }
 859                         ef->progtab[pb].size = shdr[i].sh_size;
 860                         ef->progtab[pb].sec = i;
 861                         if (shdr[i].sh_type == SHT_PROGBITS
 862 #ifdef __amd64__
 863                             || shdr[i].sh_type == SHT_X86_64_UNWIND
 864 #endif
 865                             ) {
 866                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
 867                                     ef->progtab[pb].addr,
 868                                     shdr[i].sh_size, shdr[i].sh_offset,
 869                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 870                                     NOCRED, &resid, td);
 871                                 if (error)
 872                                         goto out;
 873                                 if (resid != 0){
 874                                         error = EINVAL;
 875                                         goto out;
 876                                 }
 877                                 /* Initialize the per-cpu or vnet area. */
 878                                 if (ef->progtab[pb].addr != (void *)mapbase &&
 879                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
 880                                         dpcpu_copy(ef->progtab[pb].addr,
 881                                             shdr[i].sh_size);
 882 #ifdef VIMAGE
 883                                 else if (ef->progtab[pb].addr !=
 884                                     (void *)mapbase &&
 885                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
 886                                         vnet_data_copy(ef->progtab[pb].addr,
 887                                             shdr[i].sh_size);
 888 #endif
 889                         } else
 890                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
 891
 892                         /* Update all symbol values with the offset. */
 893                         for (j = 0; j < ef->ddbsymcnt; j++) {
 894                                 es = &ef->ddbsymtab[j];
 895                                 if (es->st_shndx != i)
 896                                         continue;
 897                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 898                         }
 899                         mapbase += shdr[i].sh_size;
 900                         pb++;
 901                         break;
 902                 case SHT_REL:
 903                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 904                                 break;
 905                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
 906                             M_WAITOK);
 907                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 908                         ef->reltab[rl].sec = shdr[i].sh_info;
 909                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 910                             (void *)ef->reltab[rl].rel,
 911                             shdr[i].sh_size, shdr[i].sh_offset,
 912                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 913                             &resid, td);
 914                         if (error)
 915                                 goto out;
 916                         if (resid != 0){
 917                                 error = EINVAL;
 918                                 goto out;
 919                         }
 920                         rl++;
 921                         break;
 922                 case SHT_RELA:
 923                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 924                                 break;
 925                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
 926                             M_WAITOK);
 927                         ef->relatab[ra].nrela =
 928                             shdr[i].sh_size / sizeof(Elf_Rela);
 929                         ef->relatab[ra].sec = shdr[i].sh_info;
 930                         error = vn_rdwr(UIO_READ, nd->ni_vp,
 931                             (void *)ef->relatab[ra].rela,
 932                             shdr[i].sh_size, shdr[i].sh_offset,
 933                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 934                             &resid, td);
 935                         if (error)
 936                                 goto out;
 937                         if (resid != 0){
 938                                 error = EINVAL;
 939                                 goto out;
 940                         }
 941                         ra++;
 942                         break;
 943                 }
 944         }
 945         if (pb != ef->nprogtab) {
 946                 link_elf_error(filename, "lost progbits");
 947                 error = ENOEXEC;
 948                 goto out;
 949         }
 950         if (rl != ef->nreltab) {
 951                 link_elf_error(filename, "lost reltab");
 952                 error = ENOEXEC;
 953                 goto out;
 954         }
 955         if (ra != ef->nrelatab) {
 956                 link_elf_error(filename, "lost relatab");
 957                 error = ENOEXEC;
 958                 goto out;
 959         }
 960         if (mapbase != (vm_offset_t)ef->address + mapsize) {
 961                 printf(
 962                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
 963                     filename != NULL ? filename : "<none>",
 964                     (u_long)mapbase, ef->address, (u_long)mapsize,
 965                     (u_long)(vm_offset_t)ef->address + mapsize);
 966                 error = ENOMEM;
 967                 goto out;
 968         }
 969
 970         /* Local intra-module relocations */
 971         error = link_elf_reloc_local(lf);
 972         if (error != 0)
 973                 goto out;
 974
 975         /* Pull in dependencies */
 976         VOP_UNLOCK(nd->ni_vp, 0);
 977         error = linker_load_dependencies(lf);
 978         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
 979         if (error)
 980                 goto out;
 981
 982         /* External relocations */
 983         error = relocate_file(ef);
 984         if (error)
 985                 goto out;
 986
 987         /* Notify MD code that a module is being loaded. */
 988         error = elf_cpu_load_file(lf);
 989         if (error)
 990                 goto out;
 991
 992         /* Invoke .ctors */
 993         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 994
 995         *result = lf;
 996
 997 out:
 998         VOP_UNLOCK(nd->ni_vp, 0);
 999         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1000         free(nd, M_TEMP);
1001         if (error && lf)
1002                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1003         free(hdr, M_LINKER);
1004
1005         return error;
1006 }
1007
1008 static void
1009 link_elf_unload_file(linker_file_t file)
1010 {
1011         elf_file_t ef = (elf_file_t) file;
1012         u_int i;
1013
1014         /* Notify MD code that a module is being unloaded. */
1015         elf_cpu_unload_file(file);
1016
1017         if (ef->progtab) {
1018                 for (i = 0; i < ef->nprogtab; i++) {
1019                         if (ef->progtab[i].size == 0)
1020                                 continue;
1021                         if (ef->progtab[i].name == NULL)
1022                                 continue;
1023                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1024                                 dpcpu_free(ef->progtab[i].addr,
1025                                     ef->progtab[i].size);
1026 #ifdef VIMAGE
1027                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1028                                 vnet_data_free(ef->progtab[i].addr,
1029                                     ef->progtab[i].size);
1030 #endif
1031                 }
1032         }
1033         if (ef->preloaded) {
1034                 free(ef->reltab, M_LINKER);
1035                 free(ef->relatab, M_LINKER);
1036                 free(ef->progtab, M_LINKER);
1037                 free(ef->ctftab, M_LINKER);
1038                 free(ef->ctfoff, M_LINKER);
1039                 free(ef->typoff, M_LINKER);
1040                 if (file->filename != NULL)
1041                         preload_delete_name(file->filename);
1042                 /* XXX reclaim module memory? */
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 = (elf_file_t) lf;
1205         const Elf_Sym *es = (const Elf_Sym*) sym;
1206
1207         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1208                 symval->name = ef->ddbstrtab + es->st_name;
1209                 symval->value = (caddr_t)es->st_value;
1210                 symval->size = es->st_size;
1211                 return 0;
1212         }
1213         return ENOENT;
1214 }
1215
1216 static int
1217 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1218     c_linker_sym_t *sym, long *diffp)
1219 {
1220         elf_file_t ef = (elf_file_t) lf;
1221         u_long off = (uintptr_t) (void *) value;
1222         u_long diff = off;
1223         u_long st_value;
1224         const Elf_Sym *es;
1225         const Elf_Sym *best = NULL;
1226         int i;
1227
1228         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1229                 if (es->st_name == 0)
1230                         continue;
1231                 st_value = es->st_value;
1232                 if (off >= st_value) {
1233                         if (off - st_value < diff) {
1234                                 diff = off - st_value;
1235                                 best = es;
1236                                 if (diff == 0)
1237                                         break;
1238                         } else if (off - st_value == diff) {
1239                                 best = es;
1240                         }
1241                 }
1242         }
1243         if (best == NULL)
1244                 *diffp = off;
1245         else
1246                 *diffp = diff;
1247         *sym = (c_linker_sym_t) best;
1248
1249         return 0;
1250 }
1251
1252 /*
1253  * Look up a linker set on an ELF system.
1254  */
1255 static int
1256 link_elf_lookup_set(linker_file_t lf, const char *name,
1257     void ***startp, void ***stopp, int *countp)
1258 {
1259         elf_file_t ef = (elf_file_t)lf;
1260         void **start, **stop;
1261         int i, count;
1262
1263         /* Relative to section number */
1264         for (i = 0; i < ef->nprogtab; i++) {
1265                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1266                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1267                         start  = (void **)ef->progtab[i].addr;
1268                         stop = (void **)((char *)ef->progtab[i].addr +
1269                             ef->progtab[i].size);
1270                         count = stop - start;
1271                         if (startp)
1272                                 *startp = start;
1273                         if (stopp)
1274                                 *stopp = stop;
1275                         if (countp)
1276                                 *countp = count;
1277                         return (0);
1278                 }
1279         }
1280         return (ESRCH);
1281 }
1282
1283 static int
1284 link_elf_each_function_name(linker_file_t file,
1285     int (*callback)(const char *, void *), void *opaque)
1286 {
1287         elf_file_t ef = (elf_file_t)file;
1288         const Elf_Sym *symp;
1289         int i, error;
1290
1291         /* Exhaustive search */
1292         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1293                 if (symp->st_value != 0 &&
1294                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1295                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1296                         if (error)
1297                                 return (error);
1298                 }
1299         }
1300         return (0);
1301 }
1302
1303 static int
1304 link_elf_each_function_nameval(linker_file_t file,
1305     linker_function_nameval_callback_t callback, void *opaque)
1306 {
1307         linker_symval_t symval;
1308         elf_file_t ef = (elf_file_t)file;
1309         const Elf_Sym* symp;
1310         int i, error;
1311
1312         /* Exhaustive search */
1313         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1314                 if (symp->st_value != 0 &&
1315                     ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
1316                         error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
1317                         if (error)
1318                                 return (error);
1319                         error = callback(file, i, &symval, opaque);
1320                         if (error)
1321                                 return (error);
1322                 }
1323         }
1324         return (0);
1325 }
1326
1327 static void
1328 elf_obj_cleanup_globals_cache(elf_file_t ef)
1329 {
1330         Elf_Sym *sym;
1331         Elf_Size i;
1332
1333         for (i = 0; i < ef->ddbsymcnt; i++) {
1334                 sym = ef->ddbsymtab + i;
1335                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1336                         sym->st_shndx = SHN_UNDEF;
1337                         sym->st_value = 0;
1338                 }
1339         }
1340 }
1341
1342 /*
1343  * Symbol lookup function that can be used when the symbol index is known (ie
1344  * in relocations). It uses the symbol index instead of doing a fully fledged
1345  * hash table based lookup when such is valid. For example for local symbols.
1346  * This is not only more efficient, it's also more correct. It's not always
1347  * the case that the symbol can be found through the hash table.
1348  */
1349 static int
1350 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1351 {
1352         elf_file_t ef = (elf_file_t)lf;
1353         Elf_Sym *sym;
1354         const char *symbol;
1355         Elf_Addr res1;
1356
1357         /* Don't even try to lookup the symbol if the index is bogus. */
1358         if (symidx >= ef->ddbsymcnt) {
1359                 *res = 0;
1360                 return (EINVAL);
1361         }
1362
1363         sym = ef->ddbsymtab + symidx;
1364
1365         /* Quick answer if there is a definition included. */
1366         if (sym->st_shndx != SHN_UNDEF) {
1367                 *res = sym->st_value;
1368                 return (0);
1369         }
1370
1371         /* If we get here, then it is undefined and needs a lookup. */
1372         switch (ELF_ST_BIND(sym->st_info)) {
1373         case STB_LOCAL:
1374                 /* Local, but undefined? huh? */
1375                 *res = 0;
1376                 return (EINVAL);
1377
1378         case STB_GLOBAL:
1379         case STB_WEAK:
1380                 /* Relative to Data or Function name */
1381                 symbol = ef->ddbstrtab + sym->st_name;
1382
1383                 /* Force a lookup failure if the symbol name is bogus. */
1384                 if (*symbol == 0) {
1385                         *res = 0;
1386                         return (EINVAL);
1387                 }
1388                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1389
1390                 /*
1391                  * Cache global lookups during module relocation. The failure
1392                  * case is particularly expensive for callers, who must scan
1393                  * through the entire globals table doing strcmp(). Cache to
1394                  * avoid doing such work repeatedly.
1395                  *
1396                  * After relocation is complete, undefined globals will be
1397                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1398                  * above.
1399                  */
1400                 if (res1 != 0) {
1401                         sym->st_shndx = SHN_FBSD_CACHED;
1402                         sym->st_value = res1;
1403                         *res = res1;
1404                         return (0);
1405                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1406                         sym->st_value = 0;
1407                         *res = 0;
1408                         return (0);
1409                 }
1410                 return (EINVAL);
1411
1412         default:
1413                 return (EINVAL);
1414         }
1415 }
1416
1417 static void
1418 link_elf_fix_link_set(elf_file_t ef)
1419 {
1420         static const char startn[] = "__start_";
1421         static const char stopn[] = "__stop_";
1422         Elf_Sym *sym;
1423         const char *sym_name, *linkset_name;
1424         Elf_Addr startp, stopp;
1425         Elf_Size symidx;
1426         int start, i;
1427
1428         startp = stopp = 0;
1429         for (symidx = 1 /* zero entry is special */;
1430                 symidx < ef->ddbsymcnt; symidx++) {
1431                 sym = ef->ddbsymtab + symidx;
1432                 if (sym->st_shndx != SHN_UNDEF)
1433                         continue;
1434
1435                 sym_name = ef->ddbstrtab + sym->st_name;
1436                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1437                         start = 1;
1438                         linkset_name = sym_name + sizeof(startn) - 1;
1439                 }
1440                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1441                         start = 0;
1442                         linkset_name = sym_name + sizeof(stopn) - 1;
1443                 }
1444                 else
1445                         continue;
1446
1447                 for (i = 0; i < ef->nprogtab; i++) {
1448                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1449                                 startp = (Elf_Addr)ef->progtab[i].addr;
1450                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1451                                 break;
1452                         }
1453                 }
1454                 if (i == ef->nprogtab)
1455                         continue;
1456
1457                 sym->st_value = start ? startp : stopp;
1458                 sym->st_shndx = i;
1459         }
1460 }
1461
1462 static int
1463 link_elf_reloc_local(linker_file_t lf)
1464 {
1465         elf_file_t ef = (elf_file_t)lf;
1466         const Elf_Rel *rellim;
1467         const Elf_Rel *rel;
1468         const Elf_Rela *relalim;
1469         const Elf_Rela *rela;
1470         const Elf_Sym *sym;
1471         Elf_Addr base;
1472         int i;
1473         Elf_Size symidx;
1474
1475         link_elf_fix_link_set(ef);
1476
1477         /* Perform relocations without addend if there are any: */
1478         for (i = 0; i < ef->nreltab; i++) {
1479                 rel = ef->reltab[i].rel;
1480                 if (rel == NULL) {
1481                         link_elf_error(ef->lf.filename, "lost a reltab");
1482                         return (ENOEXEC);
1483                 }
1484                 rellim = rel + ef->reltab[i].nrel;
1485                 base = findbase(ef, ef->reltab[i].sec);
1486                 if (base == 0) {
1487                         link_elf_error(ef->lf.filename, "lost base for reltab");
1488                         return (ENOEXEC);
1489                 }
1490                 for ( ; rel < rellim; rel++) {
1491                         symidx = ELF_R_SYM(rel->r_info);
1492                         if (symidx >= ef->ddbsymcnt)
1493                                 continue;
1494                         sym = ef->ddbsymtab + symidx;
1495                         /* Only do local relocs */
1496                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1497                                 continue;
1498                         elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1499                             elf_obj_lookup);
1500                 }
1501         }
1502
1503         /* Perform relocations with addend if there are any: */
1504         for (i = 0; i < ef->nrelatab; i++) {
1505                 rela = ef->relatab[i].rela;
1506                 if (rela == NULL) {
1507                         link_elf_error(ef->lf.filename, "lost a relatab!");
1508                         return (ENOEXEC);
1509                 }
1510                 relalim = rela + ef->relatab[i].nrela;
1511                 base = findbase(ef, ef->relatab[i].sec);
1512                 if (base == 0) {
1513                         link_elf_error(ef->lf.filename, "lost base for reltab");
1514                         return (ENOEXEC);
1515                 }
1516                 for ( ; rela < relalim; rela++) {
1517                         symidx = ELF_R_SYM(rela->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                         elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1525                             elf_obj_lookup);
1526                 }
1527         }
1528         return (0);
1529 }
1530
1531 static long
1532 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1533 {
1534     elf_file_t ef = (elf_file_t)lf;
1535
1536     *symtab = ef->ddbsymtab;
1537
1538     if (*symtab == NULL)
1539         return (0);
1540
1541     return (ef->ddbsymcnt);
1542 }
1543
1544 static long
1545 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1546 {
1547     elf_file_t ef = (elf_file_t)lf;
1548
1549     *strtab = ef->ddbstrtab;
1550
1551     if (*strtab == NULL)
1552         return (0);
1553
1554     return (ef->ddbstrcnt);
1555 }