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/fcntl.h>
  38 #include <sys/kernel.h>
  39 #include <sys/lock.h>
  40 #include <sys/malloc.h>
  41 #include <sys/linker.h>
  42 #include <sys/mutex.h>
  43 #include <sys/mount.h>
  44 #include <sys/namei.h>
  45 #include <sys/proc.h>
  46 #include <sys/rwlock.h>
  47 #include <sys/vnode.h>
  48
  49 #include <machine/elf.h>
  50
  51 #include <net/vnet.h>
  52
  53 #include <security/mac/mac_framework.h>
  54
  55 #include <vm/vm.h>
  56 #include <vm/vm_param.h>
  57 #include <vm/pmap.h>
  58 #include <vm/vm_extern.h>
  59 #include <vm/vm_kern.h>
  60 #include <vm/vm_map.h>
  61 #include <vm/vm_object.h>
  62 #include <vm/vm_page.h>
  63 #include <vm/vm_pager.h>
  64
  65 #include <sys/link_elf.h>
  66
  67 #ifdef DDB_CTF
  68 #include <contrib/zlib/zlib.h>
  69 #endif
  70
  71 #include "linker_if.h"
  72
  73 typedef struct {
  74         void            *addr;
  75         Elf_Off         size;
  76         int             flags;  /* Section flags. */
  77         int             sec;    /* Original section number. */
  78         char            *name;
  79 } Elf_progent;
  80
  81 typedef struct {
  82         Elf_Rel         *rel;
  83         int             nrel;
  84         int             sec;
  85 } Elf_relent;
  86
  87 typedef struct {
  88         Elf_Rela        *rela;
  89         int             nrela;
  90         int             sec;
  91 } Elf_relaent;
  92
  93 typedef struct elf_file {
  94         struct linker_file lf;          /* Common fields */
  95
  96         int             preloaded;
  97         caddr_t         address;        /* Relocation address */
  98         vm_object_t     object;         /* VM object to hold file pages */
  99         Elf_Shdr        *e_shdr;
 100
 101         Elf_progent     *progtab;
 102         u_int           nprogtab;
 103
 104         Elf_relaent     *relatab;
 105         u_int           nrelatab;
 106
 107         Elf_relent      *reltab;
 108         int             nreltab;
 109
 110         Elf_Sym         *ddbsymtab;     /* The symbol table we are using */
 111         long            ddbsymcnt;      /* Number of symbols */
 112         caddr_t         ddbstrtab;      /* String table */
 113         long            ddbstrcnt;      /* number of bytes in string table */
 114
 115         caddr_t         shstrtab;       /* Section name string table */
 116         long            shstrcnt;       /* number of bytes in string table */
 117
 118         caddr_t         ctftab;         /* CTF table */
 119         long            ctfcnt;         /* number of bytes in CTF table */
 120         caddr_t         ctfoff;         /* CTF offset table */
 121         caddr_t         typoff;         /* Type offset table */
 122         long            typlen;         /* Number of type entries. */
 123
 124 } *elf_file_t;
 125
 126 #include <kern/kern_ctf.c>
 127
 128 static int      link_elf_link_preload(linker_class_t cls,
 129                     const char *, linker_file_t *);
 130 static int      link_elf_link_preload_finish(linker_file_t);
 131 static int      link_elf_load_file(linker_class_t, const char *, linker_file_t *);
 132 static int      link_elf_lookup_symbol(linker_file_t, const char *,
 133                     c_linker_sym_t *);
 134 static int      link_elf_symbol_values(linker_file_t, c_linker_sym_t,
 135                     linker_symval_t *);
 136 static int      link_elf_search_symbol(linker_file_t, caddr_t value,
 137                     c_linker_sym_t *sym, long *diffp);
 138
 139 static void     link_elf_unload_file(linker_file_t);
 140 static int      link_elf_lookup_set(linker_file_t, const char *,
 141                     void ***, void ***, int *);
 142 static int      link_elf_each_function_name(linker_file_t,
 143                     int (*)(const char *, void *), void *);
 144 static int      link_elf_each_function_nameval(linker_file_t,
 145                                 linker_function_nameval_callback_t,
 146                                 void *);
 147 static int      link_elf_reloc_local(linker_file_t, bool);
 148 static long     link_elf_symtab_get(linker_file_t, const Elf_Sym **);
 149 static long     link_elf_strtab_get(linker_file_t, caddr_t *);
 150
 151 static int      elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
 152                     Elf_Addr *);
 153
 154 static kobj_method_t link_elf_methods[] = {
 155         KOBJMETHOD(linker_lookup_symbol,        link_elf_lookup_symbol),
 156         KOBJMETHOD(linker_symbol_values,        link_elf_symbol_values),
 157         KOBJMETHOD(linker_search_symbol,        link_elf_search_symbol),
 158         KOBJMETHOD(linker_unload,               link_elf_unload_file),
 159         KOBJMETHOD(linker_load_file,            link_elf_load_file),
 160         KOBJMETHOD(linker_link_preload,         link_elf_link_preload),
 161         KOBJMETHOD(linker_link_preload_finish,  link_elf_link_preload_finish),
 162         KOBJMETHOD(linker_lookup_set,           link_elf_lookup_set),
 163         KOBJMETHOD(linker_each_function_name,   link_elf_each_function_name),
 164         KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
 165         KOBJMETHOD(linker_ctf_get,              link_elf_ctf_get),
 166         KOBJMETHOD(linker_symtab_get,           link_elf_symtab_get),
 167         KOBJMETHOD(linker_strtab_get,           link_elf_strtab_get),
 168         KOBJMETHOD_END
 169 };
 170
 171 static struct linker_class link_elf_class = {
 172 #if ELF_TARG_CLASS == ELFCLASS32
 173         "elf32_obj",
 174 #else
 175         "elf64_obj",
 176 #endif
 177         link_elf_methods, sizeof(struct elf_file)
 178 };
 179
 180 static int      relocate_file(elf_file_t ef);
 181 static void     elf_obj_cleanup_globals_cache(elf_file_t);
 182
 183 static void
 184 link_elf_error(const char *filename, const char *s)
 185 {
 186         if (filename == NULL)
 187                 printf("kldload: %s\n", s);
 188         else
 189                 printf("kldload: %s: %s\n", filename, s);
 190 }
 191
 192 static void
 193 link_elf_init(void *arg)
 194 {
 195
 196         linker_add_class(&link_elf_class);
 197 }
 198 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL);
 199
 200 static void
 201 link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end,
 202     vm_prot_t prot)
 203 {
 204         int error __unused;
 205
 206         KASSERT(start <= end && start >= (vm_offset_t)ef->address &&
 207             end <= round_page((vm_offset_t)ef->address + ef->lf.size),
 208             ("link_elf_protect_range: invalid range %#jx-%#jx",
 209             (uintmax_t)start, (uintmax_t)end));
 210
 211         if (start == end)
 212                 return;
 213         if (ef->preloaded) {
 214 #ifdef __amd64__
 215                 error = pmap_change_prot(start, end - start, prot);
 216                 KASSERT(error == 0,
 217                     ("link_elf_protect_range: pmap_change_prot() returned %d",
 218                     error));
 219 #endif
 220                 return;
 221         }
 222         error = vm_map_protect(kernel_map, start, end, prot, FALSE);
 223         KASSERT(error == KERN_SUCCESS,
 224             ("link_elf_protect_range: vm_map_protect() returned %d", error));
 225 }
 226
 227 /*
 228  * Restrict permissions on linker file memory based on section flags.
 229  * Sections need not be page-aligned, so overlap within a page is possible.
 230  */
 231 static void
 232 link_elf_protect(elf_file_t ef)
 233 {
 234         vm_offset_t end, segend, segstart, start;
 235         vm_prot_t gapprot, prot, segprot;
 236         int i;
 237
 238         /*
 239          * If the file was preloaded, the last page may contain other preloaded
 240          * data which may need to be writeable.  ELF files are always
 241          * page-aligned, but other preloaded data, such as entropy or CPU
 242          * microcode may be loaded with a smaller alignment.
 243          */
 244         gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ;
 245
 246         start = end = (vm_offset_t)ef->address;
 247         prot = VM_PROT_READ;
 248         for (i = 0; i < ef->nprogtab; i++) {
 249                 /*
 250                  * VNET and DPCPU sections have their memory allocated by their
 251                  * respective subsystems.
 252                  */
 253                 if (ef->progtab[i].name != NULL && (
 254 #ifdef VIMAGE
 255                     strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 ||
 256 #endif
 257                     strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0))
 258                         continue;
 259
 260                 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr);
 261                 segend = round_page((vm_offset_t)ef->progtab[i].addr +
 262                     ef->progtab[i].size);
 263                 segprot = VM_PROT_READ;
 264                 if ((ef->progtab[i].flags & SHF_WRITE) != 0)
 265                         segprot |= VM_PROT_WRITE;
 266                 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0)
 267                         segprot |= VM_PROT_EXECUTE;
 268
 269                 if (end <= segstart) {
 270                         /*
 271                          * Case 1: there is no overlap between the previous
 272                          * segment and this one.  Apply protections to the
 273                          * previous segment, and protect the gap between the
 274                          * previous and current segments, if any.
 275                          */
 276                         link_elf_protect_range(ef, start, end, prot);
 277                         link_elf_protect_range(ef, end, segstart, gapprot);
 278
 279                         start = segstart;
 280                         end = segend;
 281                         prot = segprot;
 282                 } else if (start < segstart && end == segend) {
 283                         /*
 284                          * Case 2: the current segment is a subrange of the
 285                          * previous segment.  Apply protections to the
 286                          * non-overlapping portion of the previous segment.
 287                          */
 288                         link_elf_protect_range(ef, start, segstart, prot);
 289
 290                         start = segstart;
 291                         prot |= segprot;
 292                 } else if (end < segend) {
 293                         /*
 294                          * Case 3: there is partial overlap between the previous
 295                          * and current segments.  Apply protections to the
 296                          * non-overlapping portion of the previous segment, and
 297                          * then the overlap, which must use the union of the two
 298                          * segments' protections.
 299                          */
 300                         link_elf_protect_range(ef, start, segstart, prot);
 301                         link_elf_protect_range(ef, segstart, end,
 302                             prot | segprot);
 303                         start = end;
 304                         end = segend;
 305                         prot = segprot;
 306                 } else {
 307                         /*
 308                          * Case 4: the two segments reside in the same page.
 309                          */
 310                         prot |= segprot;
 311                 }
 312         }
 313
 314         /*
 315          * Fix up the last unprotected segment and trailing data.
 316          */
 317         link_elf_protect_range(ef, start, end, prot);
 318         link_elf_protect_range(ef, end,
 319             round_page((vm_offset_t)ef->address + ef->lf.size), gapprot);
 320 }
 321
 322 static int
 323 link_elf_link_preload(linker_class_t cls, const char *filename,
 324     linker_file_t *result)
 325 {
 326         Elf_Ehdr *hdr;
 327         Elf_Shdr *shdr;
 328         Elf_Sym *es;
 329         void *modptr, *baseptr, *sizeptr;
 330         char *type;
 331         elf_file_t ef;
 332         linker_file_t lf;
 333         Elf_Addr off;
 334         int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
 335
 336         /* Look to see if we have the file preloaded */
 337         modptr = preload_search_by_name(filename);
 338         if (modptr == NULL)
 339                 return ENOENT;
 340
 341         type = (char *)preload_search_info(modptr, MODINFO_TYPE);
 342         baseptr = preload_search_info(modptr, MODINFO_ADDR);
 343         sizeptr = preload_search_info(modptr, MODINFO_SIZE);
 344         hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
 345             MODINFOMD_ELFHDR);
 346         shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
 347             MODINFOMD_SHDR);
 348         if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
 349             " obj module") != 0 &&
 350             strcmp(type, "elf obj module") != 0)) {
 351                 return (EFTYPE);
 352         }
 353         if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
 354             shdr == NULL)
 355                 return (EINVAL);
 356
 357         lf = linker_make_file(filename, &link_elf_class);
 358         if (lf == NULL)
 359                 return (ENOMEM);
 360
 361         ef = (elf_file_t)lf;
 362         ef->preloaded = 1;
 363         ef->address = *(caddr_t *)baseptr;
 364         lf->address = *(caddr_t *)baseptr;
 365         lf->size = *(size_t *)sizeptr;
 366
 367         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 368             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 369             hdr->e_ident[EI_VERSION] != EV_CURRENT ||
 370             hdr->e_version != EV_CURRENT ||
 371             hdr->e_type != ET_REL ||
 372             hdr->e_machine != ELF_TARG_MACH) {
 373                 error = EFTYPE;
 374                 goto out;
 375         }
 376         ef->e_shdr = shdr;
 377
 378         /* Scan the section header for information and table sizing. */
 379         symtabindex = -1;
 380         symstrindex = -1;
 381         for (i = 0; i < hdr->e_shnum; i++) {
 382                 switch (shdr[i].sh_type) {
 383                 case SHT_PROGBITS:
 384                 case SHT_NOBITS:
 385 #ifdef __amd64__
 386                 case SHT_X86_64_UNWIND:
 387 #endif
 388                         /* Ignore sections not loaded by the loader. */
 389                         if (shdr[i].sh_addr == 0)
 390                                 break;
 391                         ef->nprogtab++;
 392                         break;
 393                 case SHT_SYMTAB:
 394                         symtabindex = i;
 395                         symstrindex = shdr[i].sh_link;
 396                         break;
 397                 case SHT_REL:
 398                         /*
 399                          * Ignore relocation tables for sections not
 400                          * loaded by the loader.
 401                          */
 402                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 403                                 break;
 404                         ef->nreltab++;
 405                         break;
 406                 case SHT_RELA:
 407                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 408                                 break;
 409                         ef->nrelatab++;
 410                         break;
 411                 }
 412         }
 413
 414         shstrindex = hdr->e_shstrndx;
 415         if (ef->nprogtab == 0 || symstrindex < 0 ||
 416             symstrindex >= hdr->e_shnum ||
 417             shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
 418             shstrindex >= hdr->e_shnum ||
 419             shdr[shstrindex].sh_type != SHT_STRTAB) {
 420                 printf("%s: bad/missing section headers\n", filename);
 421                 error = ENOEXEC;
 422                 goto out;
 423         }
 424
 425         /* Allocate space for tracking the load chunks */
 426         if (ef->nprogtab != 0)
 427                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 428                     M_LINKER, M_WAITOK | M_ZERO);
 429         if (ef->nreltab != 0)
 430                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 431                     M_LINKER, M_WAITOK | M_ZERO);
 432         if (ef->nrelatab != 0)
 433                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 434                     M_LINKER, M_WAITOK | M_ZERO);
 435         if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
 436             (ef->nreltab != 0 && ef->reltab == NULL) ||
 437             (ef->nrelatab != 0 && ef->relatab == NULL)) {
 438                 error = ENOMEM;
 439                 goto out;
 440         }
 441
 442         /* XXX, relocate the sh_addr fields saved by the loader. */
 443         off = 0;
 444         for (i = 0; i < hdr->e_shnum; i++) {
 445                 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
 446                         off = shdr[i].sh_addr;
 447         }
 448         for (i = 0; i < hdr->e_shnum; i++) {
 449                 if (shdr[i].sh_addr != 0)
 450                         shdr[i].sh_addr = shdr[i].sh_addr - off +
 451                             (Elf_Addr)ef->address;
 452         }
 453
 454         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 455         ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
 456         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 457         ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
 458         ef->shstrcnt = shdr[shstrindex].sh_size;
 459         ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
 460
 461         /* Now fill out progtab and the relocation tables. */
 462         pb = 0;
 463         rl = 0;
 464         ra = 0;
 465         for (i = 0; i < hdr->e_shnum; i++) {
 466                 switch (shdr[i].sh_type) {
 467                 case SHT_PROGBITS:
 468                 case SHT_NOBITS:
 469 #ifdef __amd64__
 470                 case SHT_X86_64_UNWIND:
 471 #endif
 472                         if (shdr[i].sh_addr == 0)
 473                                 break;
 474                         ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
 475                         if (shdr[i].sh_type == SHT_PROGBITS)
 476                                 ef->progtab[pb].name = "<<PROGBITS>>";
 477 #ifdef __amd64__
 478                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 479                                 ef->progtab[pb].name = "<<UNWIND>>";
 480 #endif
 481                         else
 482                                 ef->progtab[pb].name = "<<NOBITS>>";
 483                         ef->progtab[pb].size = shdr[i].sh_size;
 484                         ef->progtab[pb].flags = shdr[i].sh_flags;
 485                         ef->progtab[pb].sec = i;
 486                         if (ef->shstrtab && shdr[i].sh_name != 0)
 487                                 ef->progtab[pb].name =
 488                                     ef->shstrtab + shdr[i].sh_name;
 489                         if (ef->progtab[pb].name != NULL &&
 490                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 491                                 void *dpcpu;
 492
 493                                 dpcpu = dpcpu_alloc(shdr[i].sh_size);
 494                                 if (dpcpu == NULL) {
 495                                         printf("%s: pcpu module space is out "
 496                                             "of space; cannot allocate %#jx "
 497                                             "for %s\n", __func__,
 498                                             (uintmax_t)shdr[i].sh_size,
 499                                             filename);
 500                                         error = ENOSPC;
 501                                         goto out;
 502                                 }
 503                                 memcpy(dpcpu, ef->progtab[pb].addr,
 504                                     ef->progtab[pb].size);
 505                                 dpcpu_copy(dpcpu, shdr[i].sh_size);
 506                                 ef->progtab[pb].addr = dpcpu;
 507 #ifdef VIMAGE
 508                         } else if (ef->progtab[pb].name != NULL &&
 509                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
 510                                 void *vnet_data;
 511
 512                                 vnet_data = vnet_data_alloc(shdr[i].sh_size);
 513                                 if (vnet_data == NULL) {
 514                                         printf("%s: vnet module space is out "
 515                                             "of space; cannot allocate %#jx "
 516                                             "for %s\n", __func__,
 517                                             (uintmax_t)shdr[i].sh_size,
 518                                             filename);
 519                                         error = ENOSPC;
 520                                         goto out;
 521                                 }
 522                                 memcpy(vnet_data, ef->progtab[pb].addr,
 523                                     ef->progtab[pb].size);
 524                                 vnet_data_copy(vnet_data, shdr[i].sh_size);
 525                                 ef->progtab[pb].addr = vnet_data;
 526 #endif
 527                         } else if (ef->progtab[pb].name != NULL &&
 528                             !strcmp(ef->progtab[pb].name, ".ctors")) {
 529                                 lf->ctors_addr = ef->progtab[pb].addr;
 530                                 lf->ctors_size = shdr[i].sh_size;
 531                         }
 532
 533                         /* Update all symbol values with the offset. */
 534                         for (j = 0; j < ef->ddbsymcnt; j++) {
 535                                 es = &ef->ddbsymtab[j];
 536                                 if (es->st_shndx != i)
 537                                         continue;
 538                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
 539                         }
 540                         pb++;
 541                         break;
 542                 case SHT_REL:
 543                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 544                                 break;
 545                         ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
 546                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
 547                         ef->reltab[rl].sec = shdr[i].sh_info;
 548                         rl++;
 549                         break;
 550                 case SHT_RELA:
 551                         if (shdr[shdr[i].sh_info].sh_addr == 0)
 552                                 break;
 553                         ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
 554                         ef->relatab[ra].nrela =
 555                             shdr[i].sh_size / sizeof(Elf_Rela);
 556                         ef->relatab[ra].sec = shdr[i].sh_info;
 557                         ra++;
 558                         break;
 559                 }
 560         }
 561         if (pb != ef->nprogtab) {
 562                 printf("%s: lost progbits\n", filename);
 563                 error = ENOEXEC;
 564                 goto out;
 565         }
 566         if (rl != ef->nreltab) {
 567                 printf("%s: lost reltab\n", filename);
 568                 error = ENOEXEC;
 569                 goto out;
 570         }
 571         if (ra != ef->nrelatab) {
 572                 printf("%s: lost relatab\n", filename);
 573                 error = ENOEXEC;
 574                 goto out;
 575         }
 576
 577         /*
 578          * The file needs to be writeable and executable while applying
 579          * relocations.  Mapping protections are applied once relocation
 580          * processing is complete.
 581          */
 582         link_elf_protect_range(ef, (vm_offset_t)ef->address,
 583             round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL);
 584
 585         /* Local intra-module relocations */
 586         error = link_elf_reloc_local(lf, false);
 587         if (error != 0)
 588                 goto out;
 589         *result = lf;
 590         return (0);
 591
 592 out:
 593         /* preload not done this way */
 594         linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 595         return (error);
 596 }
 597
 598 static void
 599 link_elf_invoke_ctors(caddr_t addr, size_t size)
 600 {
 601         void (**ctor)(void);
 602         size_t i, cnt;
 603
 604         if (addr == NULL || size == 0)
 605                 return;
 606         cnt = size / sizeof(*ctor);
 607         ctor = (void *)addr;
 608         for (i = 0; i < cnt; i++) {
 609                 if (ctor[i] != NULL)
 610                         (*ctor[i])();
 611         }
 612 }
 613
 614 static int
 615 link_elf_link_preload_finish(linker_file_t lf)
 616 {
 617         elf_file_t ef;
 618         int error;
 619
 620         ef = (elf_file_t)lf;
 621         error = relocate_file(ef);
 622         if (error)
 623                 return (error);
 624
 625         /* Notify MD code that a module is being loaded. */
 626         error = elf_cpu_load_file(lf);
 627         if (error)
 628                 return (error);
 629
 630 #if defined(__i386__) || defined(__amd64__)
 631         /* Now ifuncs. */
 632         error = link_elf_reloc_local(lf, true);
 633         if (error != 0)
 634                 return (error);
 635 #endif
 636
 637         /* Apply protections now that relocation processing is complete. */
 638         link_elf_protect(ef);
 639
 640         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
 641         return (0);
 642 }
 643
 644 static int
 645 link_elf_load_file(linker_class_t cls, const char *filename,
 646     linker_file_t *result)
 647 {
 648         struct nameidata *nd;
 649         struct thread *td = curthread;  /* XXX */
 650         Elf_Ehdr *hdr;
 651         Elf_Shdr *shdr;
 652         Elf_Sym *es;
 653         int nbytes, i, j;
 654         vm_offset_t mapbase;
 655         size_t mapsize;
 656         int error = 0;
 657         ssize_t resid;
 658         int flags;
 659         elf_file_t ef;
 660         linker_file_t lf;
 661         int symtabindex;
 662         int symstrindex;
 663         int shstrindex;
 664         int nsym;
 665         int pb, rl, ra;
 666         int alignmask;
 667
 668         shdr = NULL;
 669         lf = NULL;
 670         mapsize = 0;
 671         hdr = NULL;
 672
 673         nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
 674         NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
 675         flags = FREAD;
 676         error = vn_open(nd, &flags, 0, NULL);
 677         if (error) {
 678                 free(nd, M_TEMP);
 679                 return error;
 680         }
 681         NDFREE(nd, NDF_ONLY_PNBUF);
 682         if (nd->ni_vp->v_type != VREG) {
 683                 error = ENOEXEC;
 684                 goto out;
 685         }
 686 #ifdef MAC
 687         error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
 688         if (error) {
 689                 goto out;
 690         }
 691 #endif
 692
 693         /* Read the elf header from the file. */
 694         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
 695         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
 696             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 697             &resid, td);
 698         if (error)
 699                 goto out;
 700         if (resid != 0){
 701                 error = ENOEXEC;
 702                 goto out;
 703         }
 704
 705         if (!IS_ELF(*hdr)) {
 706                 error = ENOEXEC;
 707                 goto out;
 708         }
 709
 710         if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
 711             || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
 712                 link_elf_error(filename, "Unsupported file layout");
 713                 error = ENOEXEC;
 714                 goto out;
 715         }
 716         if (hdr->e_ident[EI_VERSION] != EV_CURRENT
 717             || hdr->e_version != EV_CURRENT) {
 718                 link_elf_error(filename, "Unsupported file version");
 719                 error = ENOEXEC;
 720                 goto out;
 721         }
 722         if (hdr->e_type != ET_REL) {
 723                 error = ENOSYS;
 724                 goto out;
 725         }
 726         if (hdr->e_machine != ELF_TARG_MACH) {
 727                 link_elf_error(filename, "Unsupported machine");
 728                 error = ENOEXEC;
 729                 goto out;
 730         }
 731
 732         lf = linker_make_file(filename, &link_elf_class);
 733         if (!lf) {
 734                 error = ENOMEM;
 735                 goto out;
 736         }
 737         ef = (elf_file_t) lf;
 738         ef->nprogtab = 0;
 739         ef->e_shdr = 0;
 740         ef->nreltab = 0;
 741         ef->nrelatab = 0;
 742
 743         /* Allocate and read in the section header */
 744         nbytes = hdr->e_shnum * hdr->e_shentsize;
 745         if (nbytes == 0 || hdr->e_shoff == 0 ||
 746             hdr->e_shentsize != sizeof(Elf_Shdr)) {
 747                 error = ENOEXEC;
 748                 goto out;
 749         }
 750         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
 751         ef->e_shdr = shdr;
 752         error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
 753             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
 754             NOCRED, &resid, td);
 755         if (error)
 756                 goto out;
 757         if (resid) {
 758                 error = ENOEXEC;
 759                 goto out;
 760         }
 761
 762         /* Scan the section header for information and table sizing. */
 763         nsym = 0;
 764         symtabindex = -1;
 765         symstrindex = -1;
 766         for (i = 0; i < hdr->e_shnum; i++) {
 767                 if (shdr[i].sh_size == 0)
 768                         continue;
 769                 switch (shdr[i].sh_type) {
 770                 case SHT_PROGBITS:
 771                 case SHT_NOBITS:
 772 #ifdef __amd64__
 773                 case SHT_X86_64_UNWIND:
 774 #endif
 775                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 776                                 break;
 777                         ef->nprogtab++;
 778                         break;
 779                 case SHT_SYMTAB:
 780                         nsym++;
 781                         symtabindex = i;
 782                         symstrindex = shdr[i].sh_link;
 783                         break;
 784                 case SHT_REL:
 785                         /*
 786                          * Ignore relocation tables for unallocated
 787                          * sections.
 788                          */
 789                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 790                                 break;
 791                         ef->nreltab++;
 792                         break;
 793                 case SHT_RELA:
 794                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
 795                                 break;
 796                         ef->nrelatab++;
 797                         break;
 798                 case SHT_STRTAB:
 799                         break;
 800                 }
 801         }
 802         if (ef->nprogtab == 0) {
 803                 link_elf_error(filename, "file has no contents");
 804                 error = ENOEXEC;
 805                 goto out;
 806         }
 807         if (nsym != 1) {
 808                 /* Only allow one symbol table for now */
 809                 link_elf_error(filename,
 810                     "file must have exactly one symbol table");
 811                 error = ENOEXEC;
 812                 goto out;
 813         }
 814         if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
 815             shdr[symstrindex].sh_type != SHT_STRTAB) {
 816                 link_elf_error(filename, "file has invalid symbol strings");
 817                 error = ENOEXEC;
 818                 goto out;
 819         }
 820
 821         /* Allocate space for tracking the load chunks */
 822         if (ef->nprogtab != 0)
 823                 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
 824                     M_LINKER, M_WAITOK | M_ZERO);
 825         if (ef->nreltab != 0)
 826                 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
 827                     M_LINKER, M_WAITOK | M_ZERO);
 828         if (ef->nrelatab != 0)
 829                 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
 830                     M_LINKER, M_WAITOK | M_ZERO);
 831
 832         if (symtabindex == -1) {
 833                 link_elf_error(filename, "lost symbol table index");
 834                 error = ENOEXEC;
 835                 goto out;
 836         }
 837         /* Allocate space for and load the symbol table */
 838         ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
 839         ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
 840         error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
 841             shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
 842             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 843             &resid, td);
 844         if (error)
 845                 goto out;
 846         if (resid != 0){
 847                 error = EINVAL;
 848                 goto out;
 849         }
 850
 851         /* Allocate space for and load the symbol strings */
 852         ef->ddbstrcnt = shdr[symstrindex].sh_size;
 853         ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
 854         error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
 855             shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
 856             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 857             &resid, td);
 858         if (error)
 859                 goto out;
 860         if (resid != 0){
 861                 error = EINVAL;
 862                 goto out;
 863         }
 864
 865         /* Do we have a string table for the section names?  */
 866         shstrindex = -1;
 867         if (hdr->e_shstrndx != 0 &&
 868             shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
 869                 shstrindex = hdr->e_shstrndx;
 870                 ef->shstrcnt = shdr[shstrindex].sh_size;
 871                 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
 872                     M_WAITOK);
 873                 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
 874                     shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
 875                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
 876                     &resid, td);
 877                 if (error)
 878                         goto out;
 879                 if (resid != 0){
 880                         error = EINVAL;
 881                         goto out;
 882                 }
 883         }
 884
 885         /* Size up code/data(progbits) and bss(nobits). */
 886         alignmask = 0;
 887         for (i = 0; i < hdr->e_shnum; i++) {
 888                 if (shdr[i].sh_size == 0)
 889                         continue;
 890                 switch (shdr[i].sh_type) {
 891                 case SHT_PROGBITS:
 892                 case SHT_NOBITS:
 893 #ifdef __amd64__
 894                 case SHT_X86_64_UNWIND:
 895 #endif
 896                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 897                                 break;
 898                         alignmask = shdr[i].sh_addralign - 1;
 899                         mapsize += alignmask;
 900                         mapsize &= ~alignmask;
 901                         mapsize += shdr[i].sh_size;
 902                         break;
 903                 }
 904         }
 905
 906         /*
 907          * We know how much space we need for the text/data/bss/etc.
 908          * This stuff needs to be in a single chunk so that profiling etc
 909          * can get the bounds and gdb can associate offsets with modules
 910          */
 911         ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize),
 912             VM_PROT_ALL, 0, thread0.td_ucred);
 913         if (ef->object == NULL) {
 914                 error = ENOMEM;
 915                 goto out;
 916         }
 917 #if VM_NRESERVLEVEL > 0
 918         vm_object_color(ef->object, 0);
 919 #endif
 920
 921         /*
 922          * In order to satisfy amd64's architectural requirements on the
 923          * location of code and data in the kernel's address space, request a
 924          * mapping that is above the kernel.
 925          *
 926          * Protections will be restricted once relocations are applied.
 927          */
 928 #ifdef __amd64__
 929         mapbase = KERNBASE;
 930 #else
 931         mapbase = VM_MIN_KERNEL_ADDRESS;
 932 #endif
 933         error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
 934             round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
 935             VM_PROT_ALL, 0);
 936         if (error != KERN_SUCCESS) {
 937                 vm_object_deallocate(ef->object);
 938                 ef->object = NULL;
 939                 error = ENOMEM;
 940                 goto out;
 941         }
 942
 943         /* Wire the pages */
 944         error = vm_map_wire(kernel_map, mapbase,
 945             mapbase + round_page(mapsize),
 946             VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
 947         if (error != KERN_SUCCESS) {
 948                 error = ENOMEM;
 949                 goto out;
 950         }
 951
 952         /* Inform the kld system about the situation */
 953         lf->address = ef->address = (caddr_t)mapbase;
 954         lf->size = mapsize;
 955
 956         /*
 957          * Now load code/data(progbits), zero bss(nobits), allocate space for
 958          * and load relocs
 959          */
 960         pb = 0;
 961         rl = 0;
 962         ra = 0;
 963         alignmask = 0;
 964         for (i = 0; i < hdr->e_shnum; i++) {
 965                 if (shdr[i].sh_size == 0)
 966                         continue;
 967                 switch (shdr[i].sh_type) {
 968                 case SHT_PROGBITS:
 969                 case SHT_NOBITS:
 970 #ifdef __amd64__
 971                 case SHT_X86_64_UNWIND:
 972 #endif
 973                         if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
 974                                 break;
 975                         alignmask = shdr[i].sh_addralign - 1;
 976                         mapbase += alignmask;
 977                         mapbase &= ~alignmask;
 978                         if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
 979                                 ef->progtab[pb].name =
 980                                     ef->shstrtab + shdr[i].sh_name;
 981                                 if (!strcmp(ef->progtab[pb].name, ".ctors")) {
 982                                         lf->ctors_addr = (caddr_t)mapbase;
 983                                         lf->ctors_size = shdr[i].sh_size;
 984                                 }
 985                         } else if (shdr[i].sh_type == SHT_PROGBITS)
 986                                 ef->progtab[pb].name = "<<PROGBITS>>";
 987 #ifdef __amd64__
 988                         else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
 989                                 ef->progtab[pb].name = "<<UNWIND>>";
 990 #endif
 991                         else
 992                                 ef->progtab[pb].name = "<<NOBITS>>";
 993                         if (ef->progtab[pb].name != NULL &&
 994                             !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
 995                                 ef->progtab[pb].addr =
 996                                     dpcpu_alloc(shdr[i].sh_size);
 997                                 if (ef->progtab[pb].addr == NULL) {
 998                                         printf("%s: pcpu module space is out "
 999                                             "of space; cannot allocate %#jx "
1000                                             "for %s\n", __func__,
1001                                             (uintmax_t)shdr[i].sh_size,
1002                                             filename);
1003                                 }
1004                         }
1005 #ifdef VIMAGE
1006                         else if (ef->progtab[pb].name != NULL &&
1007                             !strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
1008                                 ef->progtab[pb].addr =
1009                                     vnet_data_alloc(shdr[i].sh_size);
1010                                 if (ef->progtab[pb].addr == NULL) {
1011                                         printf("%s: vnet module space is out "
1012                                             "of space; cannot allocate %#jx "
1013                                             "for %s\n", __func__,
1014                                             (uintmax_t)shdr[i].sh_size,
1015                                             filename);
1016                                 }
1017                         }
1018 #endif
1019                         else
1020                                 ef->progtab[pb].addr =
1021                                     (void *)(uintptr_t)mapbase;
1022                         if (ef->progtab[pb].addr == NULL) {
1023                                 error = ENOSPC;
1024                                 goto out;
1025                         }
1026                         ef->progtab[pb].size = shdr[i].sh_size;
1027                         ef->progtab[pb].flags = shdr[i].sh_flags;
1028                         ef->progtab[pb].sec = i;
1029                         if (shdr[i].sh_type == SHT_PROGBITS
1030 #ifdef __amd64__
1031                             || shdr[i].sh_type == SHT_X86_64_UNWIND
1032 #endif
1033                             ) {
1034                                 error = vn_rdwr(UIO_READ, nd->ni_vp,
1035                                     ef->progtab[pb].addr,
1036                                     shdr[i].sh_size, shdr[i].sh_offset,
1037                                     UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
1038                                     NOCRED, &resid, td);
1039                                 if (error)
1040                                         goto out;
1041                                 if (resid != 0){
1042                                         error = EINVAL;
1043                                         goto out;
1044                                 }
1045                                 /* Initialize the per-cpu or vnet area. */
1046                                 if (ef->progtab[pb].addr != (void *)mapbase &&
1047                                     !strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
1048                                         dpcpu_copy(ef->progtab[pb].addr,
1049                                             shdr[i].sh_size);
1050 #ifdef VIMAGE
1051                                 else if (ef->progtab[pb].addr !=
1052                                     (void *)mapbase &&
1053                                     !strcmp(ef->progtab[pb].name, VNET_SETNAME))
1054                                         vnet_data_copy(ef->progtab[pb].addr,
1055                                             shdr[i].sh_size);
1056 #endif
1057                         } else
1058                                 bzero(ef->progtab[pb].addr, shdr[i].sh_size);
1059
1060                         /* Update all symbol values with the offset. */
1061                         for (j = 0; j < ef->ddbsymcnt; j++) {
1062                                 es = &ef->ddbsymtab[j];
1063                                 if (es->st_shndx != i)
1064                                         continue;
1065                                 es->st_value += (Elf_Addr)ef->progtab[pb].addr;
1066                         }
1067                         mapbase += shdr[i].sh_size;
1068                         pb++;
1069                         break;
1070                 case SHT_REL:
1071                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1072                                 break;
1073                         ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
1074                             M_WAITOK);
1075                         ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
1076                         ef->reltab[rl].sec = shdr[i].sh_info;
1077                         error = vn_rdwr(UIO_READ, nd->ni_vp,
1078                             (void *)ef->reltab[rl].rel,
1079                             shdr[i].sh_size, shdr[i].sh_offset,
1080                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1081                             &resid, td);
1082                         if (error)
1083                                 goto out;
1084                         if (resid != 0){
1085                                 error = EINVAL;
1086                                 goto out;
1087                         }
1088                         rl++;
1089                         break;
1090                 case SHT_RELA:
1091                         if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
1092                                 break;
1093                         ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
1094                             M_WAITOK);
1095                         ef->relatab[ra].nrela =
1096                             shdr[i].sh_size / sizeof(Elf_Rela);
1097                         ef->relatab[ra].sec = shdr[i].sh_info;
1098                         error = vn_rdwr(UIO_READ, nd->ni_vp,
1099                             (void *)ef->relatab[ra].rela,
1100                             shdr[i].sh_size, shdr[i].sh_offset,
1101                             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
1102                             &resid, td);
1103                         if (error)
1104                                 goto out;
1105                         if (resid != 0){
1106                                 error = EINVAL;
1107                                 goto out;
1108                         }
1109                         ra++;
1110                         break;
1111                 }
1112         }
1113         if (pb != ef->nprogtab) {
1114                 link_elf_error(filename, "lost progbits");
1115                 error = ENOEXEC;
1116                 goto out;
1117         }
1118         if (rl != ef->nreltab) {
1119                 link_elf_error(filename, "lost reltab");
1120                 error = ENOEXEC;
1121                 goto out;
1122         }
1123         if (ra != ef->nrelatab) {
1124                 link_elf_error(filename, "lost relatab");
1125                 error = ENOEXEC;
1126                 goto out;
1127         }
1128         if (mapbase != (vm_offset_t)ef->address + mapsize) {
1129                 printf(
1130                     "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
1131                     filename != NULL ? filename : "<none>",
1132                     (u_long)mapbase, ef->address, (u_long)mapsize,
1133                     (u_long)(vm_offset_t)ef->address + mapsize);
1134                 error = ENOMEM;
1135                 goto out;
1136         }
1137
1138         /* Local intra-module relocations */
1139         error = link_elf_reloc_local(lf, false);
1140         if (error != 0)
1141                 goto out;
1142
1143         /* Pull in dependencies */
1144         VOP_UNLOCK(nd->ni_vp);
1145         error = linker_load_dependencies(lf);
1146         vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
1147         if (error)
1148                 goto out;
1149
1150         /* External relocations */
1151         error = relocate_file(ef);
1152         if (error)
1153                 goto out;
1154
1155         /* Notify MD code that a module is being loaded. */
1156         error = elf_cpu_load_file(lf);
1157         if (error)
1158                 goto out;
1159
1160 #if defined(__i386__) || defined(__amd64__)
1161         /* Now ifuncs. */
1162         error = link_elf_reloc_local(lf, true);
1163         if (error != 0)
1164                 goto out;
1165 #endif
1166
1167         link_elf_protect(ef);
1168         link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
1169         *result = lf;
1170
1171 out:
1172         VOP_UNLOCK(nd->ni_vp);
1173         vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
1174         free(nd, M_TEMP);
1175         if (error && lf)
1176                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
1177         free(hdr, M_LINKER);
1178
1179         return error;
1180 }
1181
1182 static void
1183 link_elf_unload_file(linker_file_t file)
1184 {
1185         elf_file_t ef = (elf_file_t) file;
1186         u_int i;
1187
1188         /* Notify MD code that a module is being unloaded. */
1189         elf_cpu_unload_file(file);
1190
1191         if (ef->progtab) {
1192                 for (i = 0; i < ef->nprogtab; i++) {
1193                         if (ef->progtab[i].size == 0)
1194                                 continue;
1195                         if (ef->progtab[i].name == NULL)
1196                                 continue;
1197                         if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
1198                                 dpcpu_free(ef->progtab[i].addr,
1199                                     ef->progtab[i].size);
1200 #ifdef VIMAGE
1201                         else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
1202                                 vnet_data_free(ef->progtab[i].addr,
1203                                     ef->progtab[i].size);
1204 #endif
1205                 }
1206         }
1207         if (ef->preloaded) {
1208                 free(ef->reltab, M_LINKER);
1209                 free(ef->relatab, M_LINKER);
1210                 free(ef->progtab, M_LINKER);
1211                 free(ef->ctftab, M_LINKER);
1212                 free(ef->ctfoff, M_LINKER);
1213                 free(ef->typoff, M_LINKER);
1214                 if (file->pathname != NULL)
1215                         preload_delete_name(file->pathname);
1216                 return;
1217         }
1218
1219         for (i = 0; i < ef->nreltab; i++)
1220                 free(ef->reltab[i].rel, M_LINKER);
1221         for (i = 0; i < ef->nrelatab; i++)
1222                 free(ef->relatab[i].rela, M_LINKER);
1223         free(ef->reltab, M_LINKER);
1224         free(ef->relatab, M_LINKER);
1225         free(ef->progtab, M_LINKER);
1226
1227         if (ef->object != NULL)
1228                 vm_map_remove(kernel_map, (vm_offset_t)ef->address,
1229                     (vm_offset_t)ef->address + ptoa(ef->object->size));
1230         free(ef->e_shdr, M_LINKER);
1231         free(ef->ddbsymtab, M_LINKER);
1232         free(ef->ddbstrtab, M_LINKER);
1233         free(ef->shstrtab, M_LINKER);
1234         free(ef->ctftab, M_LINKER);
1235         free(ef->ctfoff, M_LINKER);
1236         free(ef->typoff, M_LINKER);
1237 }
1238
1239 static const char *
1240 symbol_name(elf_file_t ef, Elf_Size r_info)
1241 {
1242         const Elf_Sym *ref;
1243
1244         if (ELF_R_SYM(r_info)) {
1245                 ref = ef->ddbsymtab + ELF_R_SYM(r_info);
1246                 return ef->ddbstrtab + ref->st_name;
1247         } else
1248                 return NULL;
1249 }
1250
1251 static Elf_Addr
1252 findbase(elf_file_t ef, int sec)
1253 {
1254         int i;
1255         Elf_Addr base = 0;
1256
1257         for (i = 0; i < ef->nprogtab; i++) {
1258                 if (sec == ef->progtab[i].sec) {
1259                         base = (Elf_Addr)ef->progtab[i].addr;
1260                         break;
1261                 }
1262         }
1263         return base;
1264 }
1265
1266 static int
1267 relocate_file(elf_file_t ef)
1268 {
1269         const Elf_Rel *rellim;
1270         const Elf_Rel *rel;
1271         const Elf_Rela *relalim;
1272         const Elf_Rela *rela;
1273         const char *symname;
1274         const Elf_Sym *sym;
1275         int i;
1276         Elf_Size symidx;
1277         Elf_Addr base;
1278
1279         /* Perform relocations without addend if there are any: */
1280         for (i = 0; i < ef->nreltab; i++) {
1281                 rel = ef->reltab[i].rel;
1282                 if (rel == NULL) {
1283                         link_elf_error(ef->lf.filename, "lost a reltab!");
1284                         return (ENOEXEC);
1285                 }
1286                 rellim = rel + ef->reltab[i].nrel;
1287                 base = findbase(ef, ef->reltab[i].sec);
1288                 if (base == 0) {
1289                         link_elf_error(ef->lf.filename, "lost base for reltab");
1290                         return (ENOEXEC);
1291                 }
1292                 for ( ; rel < rellim; rel++) {
1293                         symidx = ELF_R_SYM(rel->r_info);
1294                         if (symidx >= ef->ddbsymcnt)
1295                                 continue;
1296                         sym = ef->ddbsymtab + symidx;
1297                         /* Local relocs are already done */
1298                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1299                                 continue;
1300                         if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
1301                             elf_obj_lookup)) {
1302                                 symname = symbol_name(ef, rel->r_info);
1303                                 printf("link_elf_obj: symbol %s undefined\n",
1304                                     symname);
1305                                 return (ENOENT);
1306                         }
1307                 }
1308         }
1309
1310         /* Perform relocations with addend if there are any: */
1311         for (i = 0; i < ef->nrelatab; i++) {
1312                 rela = ef->relatab[i].rela;
1313                 if (rela == NULL) {
1314                         link_elf_error(ef->lf.filename, "lost a relatab!");
1315                         return (ENOEXEC);
1316                 }
1317                 relalim = rela + ef->relatab[i].nrela;
1318                 base = findbase(ef, ef->relatab[i].sec);
1319                 if (base == 0) {
1320                         link_elf_error(ef->lf.filename,
1321                             "lost base for relatab");
1322                         return (ENOEXEC);
1323                 }
1324                 for ( ; rela < relalim; rela++) {
1325                         symidx = ELF_R_SYM(rela->r_info);
1326                         if (symidx >= ef->ddbsymcnt)
1327                                 continue;
1328                         sym = ef->ddbsymtab + symidx;
1329                         /* Local relocs are already done */
1330                         if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
1331                                 continue;
1332                         if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
1333                             elf_obj_lookup)) {
1334                                 symname = symbol_name(ef, rela->r_info);
1335                                 printf("link_elf_obj: symbol %s undefined\n",
1336                                     symname);
1337                                 return (ENOENT);
1338                         }
1339                 }
1340         }
1341
1342         /*
1343          * Only clean SHN_FBSD_CACHED for successful return.  If we
1344          * modified symbol table for the object but found an
1345          * unresolved symbol, there is no reason to roll back.
1346          */
1347         elf_obj_cleanup_globals_cache(ef);
1348
1349         return (0);
1350 }
1351
1352 static int
1353 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
1354 {
1355         elf_file_t ef = (elf_file_t) lf;
1356         const Elf_Sym *symp;
1357         const char *strp;
1358         int i;
1359
1360         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1361                 strp = ef->ddbstrtab + symp->st_name;
1362                 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
1363                         *sym = (c_linker_sym_t) symp;
1364                         return 0;
1365                 }
1366         }
1367         return ENOENT;
1368 }
1369
1370 static int
1371 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
1372     linker_symval_t *symval)
1373 {
1374         elf_file_t ef;
1375         const Elf_Sym *es;
1376         caddr_t val;
1377
1378         ef = (elf_file_t) lf;
1379         es = (const Elf_Sym*) sym;
1380         val = (caddr_t)es->st_value;
1381         if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
1382                 symval->name = ef->ddbstrtab + es->st_name;
1383                 val = (caddr_t)es->st_value;
1384                 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
1385                         val = ((caddr_t (*)(void))val)();
1386                 symval->value = val;
1387                 symval->size = es->st_size;
1388                 return 0;
1389         }
1390         return ENOENT;
1391 }
1392
1393 static int
1394 link_elf_search_symbol(linker_file_t lf, caddr_t value,
1395     c_linker_sym_t *sym, long *diffp)
1396 {
1397         elf_file_t ef = (elf_file_t) lf;
1398         u_long off = (uintptr_t) (void *) value;
1399         u_long diff = off;
1400         u_long st_value;
1401         const Elf_Sym *es;
1402         const Elf_Sym *best = NULL;
1403         int i;
1404
1405         for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
1406                 if (es->st_name == 0)
1407                         continue;
1408                 st_value = es->st_value;
1409                 if (off >= st_value) {
1410                         if (off - st_value < diff) {
1411                                 diff = off - st_value;
1412                                 best = es;
1413                                 if (diff == 0)
1414                                         break;
1415                         } else if (off - st_value == diff) {
1416                                 best = es;
1417                         }
1418                 }
1419         }
1420         if (best == NULL)
1421                 *diffp = off;
1422         else
1423                 *diffp = diff;
1424         *sym = (c_linker_sym_t) best;
1425
1426         return 0;
1427 }
1428
1429 /*
1430  * Look up a linker set on an ELF system.
1431  */
1432 static int
1433 link_elf_lookup_set(linker_file_t lf, const char *name,
1434     void ***startp, void ***stopp, int *countp)
1435 {
1436         elf_file_t ef = (elf_file_t)lf;
1437         void **start, **stop;
1438         int i, count;
1439
1440         /* Relative to section number */
1441         for (i = 0; i < ef->nprogtab; i++) {
1442                 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
1443                     strcmp(ef->progtab[i].name + 4, name) == 0) {
1444                         start  = (void **)ef->progtab[i].addr;
1445                         stop = (void **)((char *)ef->progtab[i].addr +
1446                             ef->progtab[i].size);
1447                         count = stop - start;
1448                         if (startp)
1449                                 *startp = start;
1450                         if (stopp)
1451                                 *stopp = stop;
1452                         if (countp)
1453                                 *countp = count;
1454                         return (0);
1455                 }
1456         }
1457         return (ESRCH);
1458 }
1459
1460 static int
1461 link_elf_each_function_name(linker_file_t file,
1462     int (*callback)(const char *, void *), void *opaque)
1463 {
1464         elf_file_t ef = (elf_file_t)file;
1465         const Elf_Sym *symp;
1466         int i, error;
1467
1468         /* Exhaustive search */
1469         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1470                 if (symp->st_value != 0 &&
1471                     (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1472                     ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1473                         error = callback(ef->ddbstrtab + symp->st_name, opaque);
1474                         if (error)
1475                                 return (error);
1476                 }
1477         }
1478         return (0);
1479 }
1480
1481 static int
1482 link_elf_each_function_nameval(linker_file_t file,
1483     linker_function_nameval_callback_t callback, void *opaque)
1484 {
1485         linker_symval_t symval;
1486         elf_file_t ef = (elf_file_t)file;
1487         const Elf_Sym* symp;
1488         int i, error;
1489
1490         /* Exhaustive search */
1491         for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
1492                 if (symp->st_value != 0 &&
1493                     (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
1494                     ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
1495                         error = link_elf_symbol_values(file,
1496                             (c_linker_sym_t)symp, &symval);
1497                         if (error)
1498                                 return (error);
1499                         error = callback(file, i, &symval, opaque);
1500                         if (error)
1501                                 return (error);
1502                 }
1503         }
1504         return (0);
1505 }
1506
1507 static void
1508 elf_obj_cleanup_globals_cache(elf_file_t ef)
1509 {
1510         Elf_Sym *sym;
1511         Elf_Size i;
1512
1513         for (i = 0; i < ef->ddbsymcnt; i++) {
1514                 sym = ef->ddbsymtab + i;
1515                 if (sym->st_shndx == SHN_FBSD_CACHED) {
1516                         sym->st_shndx = SHN_UNDEF;
1517                         sym->st_value = 0;
1518                 }
1519         }
1520 }
1521
1522 /*
1523  * Symbol lookup function that can be used when the symbol index is known (ie
1524  * in relocations). It uses the symbol index instead of doing a fully fledged
1525  * hash table based lookup when such is valid. For example for local symbols.
1526  * This is not only more efficient, it's also more correct. It's not always
1527  * the case that the symbol can be found through the hash table.
1528  */
1529 static int
1530 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
1531 {
1532         elf_file_t ef = (elf_file_t)lf;
1533         Elf_Sym *sym;
1534         const char *symbol;
1535         Elf_Addr res1;
1536
1537         /* Don't even try to lookup the symbol if the index is bogus. */
1538         if (symidx >= ef->ddbsymcnt) {
1539                 *res = 0;
1540                 return (EINVAL);
1541         }
1542
1543         sym = ef->ddbsymtab + symidx;
1544
1545         /* Quick answer if there is a definition included. */
1546         if (sym->st_shndx != SHN_UNDEF) {
1547                 res1 = (Elf_Addr)sym->st_value;
1548                 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
1549                         res1 = ((Elf_Addr (*)(void))res1)();
1550                 *res = res1;
1551                 return (0);
1552         }
1553
1554         /* If we get here, then it is undefined and needs a lookup. */
1555         switch (ELF_ST_BIND(sym->st_info)) {
1556         case STB_LOCAL:
1557                 /* Local, but undefined? huh? */
1558                 *res = 0;
1559                 return (EINVAL);
1560
1561         case STB_GLOBAL:
1562         case STB_WEAK:
1563                 /* Relative to Data or Function name */
1564                 symbol = ef->ddbstrtab + sym->st_name;
1565
1566                 /* Force a lookup failure if the symbol name is bogus. */
1567                 if (*symbol == 0) {
1568                         *res = 0;
1569                         return (EINVAL);
1570                 }
1571                 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
1572
1573                 /*
1574                  * Cache global lookups during module relocation. The failure
1575                  * case is particularly expensive for callers, who must scan
1576                  * through the entire globals table doing strcmp(). Cache to
1577                  * avoid doing such work repeatedly.
1578                  *
1579                  * After relocation is complete, undefined globals will be
1580                  * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
1581                  * above.
1582                  */
1583                 if (res1 != 0) {
1584                         sym->st_shndx = SHN_FBSD_CACHED;
1585                         sym->st_value = res1;
1586                         *res = res1;
1587                         return (0);
1588                 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1589                         sym->st_value = 0;
1590                         *res = 0;
1591                         return (0);
1592                 }
1593                 return (EINVAL);
1594
1595         default:
1596                 return (EINVAL);
1597         }
1598 }
1599
1600 static void
1601 link_elf_fix_link_set(elf_file_t ef)
1602 {
1603         static const char startn[] = "__start_";
1604         static const char stopn[] = "__stop_";
1605         Elf_Sym *sym;
1606         const char *sym_name, *linkset_name;
1607         Elf_Addr startp, stopp;
1608         Elf_Size symidx;
1609         int start, i;
1610
1611         startp = stopp = 0;
1612         for (symidx = 1 /* zero entry is special */;
1613                 symidx < ef->ddbsymcnt; symidx++) {
1614                 sym = ef->ddbsymtab + symidx;
1615                 if (sym->st_shndx != SHN_UNDEF)
1616                         continue;
1617
1618                 sym_name = ef->ddbstrtab + sym->st_name;
1619                 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
1620                         start = 1;
1621                         linkset_name = sym_name + sizeof(startn) - 1;
1622                 }
1623                 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
1624                         start = 0;
1625                         linkset_name = sym_name + sizeof(stopn) - 1;
1626                 }
1627                 else
1628                         continue;
1629
1630                 for (i = 0; i < ef->nprogtab; i++) {
1631                         if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
1632                                 startp = (Elf_Addr)ef->progtab[i].addr;
1633                                 stopp = (Elf_Addr)(startp + ef->progtab[i].size);
1634                                 break;
1635                         }
1636                 }
1637                 if (i == ef->nprogtab)
1638                         continue;
1639
1640                 sym->st_value = start ? startp : stopp;
1641                 sym->st_shndx = i;
1642         }
1643 }
1644
1645 static int
1646 link_elf_reloc_local(linker_file_t lf, bool ifuncs)
1647 {
1648         elf_file_t ef = (elf_file_t)lf;
1649         const Elf_Rel *rellim;
1650         const Elf_Rel *rel;
1651         const Elf_Rela *relalim;
1652         const Elf_Rela *rela;
1653         const Elf_Sym *sym;
1654         Elf_Addr base;
1655         int i;
1656         Elf_Size symidx;
1657
1658         link_elf_fix_link_set(ef);
1659
1660         /* Perform relocations without addend if there are any: */
1661         for (i = 0; i < ef->nreltab; i++) {
1662                 rel = ef->reltab[i].rel;
1663                 if (rel == NULL) {
1664                         link_elf_error(ef->lf.filename, "lost a reltab");
1665                         return (ENOEXEC);
1666                 }
1667                 rellim = rel + ef->reltab[i].nrel;
1668                 base = findbase(ef, ef->reltab[i].sec);
1669                 if (base == 0) {
1670                         link_elf_error(ef->lf.filename, "lost base for reltab");
1671                         return (ENOEXEC);
1672                 }
1673                 for ( ; rel < rellim; rel++) {
1674                         symidx = ELF_R_SYM(rel->r_info);
1675                         if (symidx >= ef->ddbsymcnt)
1676                                 continue;
1677                         sym = ef->ddbsymtab + symidx;
1678                         /* Only do local relocs */
1679                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1680                                 continue;
1681                         if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1682                             elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
1683                                 continue;
1684                         if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
1685                             elf_obj_lookup) != 0)
1686                                 return (ENOEXEC);
1687                 }
1688         }
1689
1690         /* Perform relocations with addend if there are any: */
1691         for (i = 0; i < ef->nrelatab; i++) {
1692                 rela = ef->relatab[i].rela;
1693                 if (rela == NULL) {
1694                         link_elf_error(ef->lf.filename, "lost a relatab!");
1695                         return (ENOEXEC);
1696                 }
1697                 relalim = rela + ef->relatab[i].nrela;
1698                 base = findbase(ef, ef->relatab[i].sec);
1699                 if (base == 0) {
1700                         link_elf_error(ef->lf.filename, "lost base for reltab");
1701                         return (ENOEXEC);
1702                 }
1703                 for ( ; rela < relalim; rela++) {
1704                         symidx = ELF_R_SYM(rela->r_info);
1705                         if (symidx >= ef->ddbsymcnt)
1706                                 continue;
1707                         sym = ef->ddbsymtab + symidx;
1708                         /* Only do local relocs */
1709                         if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
1710                                 continue;
1711                         if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
1712                             elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
1713                                 continue;
1714                         if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
1715                             elf_obj_lookup) != 0)
1716                                 return (ENOEXEC);
1717                 }
1718         }
1719         return (0);
1720 }
1721
1722 static long
1723 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
1724 {
1725     elf_file_t ef = (elf_file_t)lf;
1726
1727     *symtab = ef->ddbsymtab;
1728
1729     if (*symtab == NULL)
1730         return (0);
1731
1732     return (ef->ddbsymcnt);
1733 }
1734
1735 static long
1736 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
1737 {
1738     elf_file_t ef = (elf_file_t)lf;
1739
1740     *strtab = ef->ddbstrtab;
1741
1742     if (*strtab == NULL)
1743         return (0);
1744
1745     return (ef->ddbstrcnt);
1746 }