| 1 | /*- |
| 2 | * Copyright (c) 1998 Doug Rabson |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * |
| 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| 15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 24 | * SUCH DAMAGE. |
| 25 | * |
| 26 | * $FreeBSD: src/sys/kern/link_elf.c,v 1.24 1999/12/24 15:33:36 bde Exp $ |
| 27 | * $DragonFly: src/sys/kern/link_elf.c,v 1.23 2006/12/20 18:14:41 dillon Exp $ |
| 28 | */ |
| 29 | |
| 30 | #include <sys/param.h> |
| 31 | #include <sys/kernel.h> |
| 32 | #include <sys/systm.h> |
| 33 | #include <sys/malloc.h> |
| 34 | #include <sys/proc.h> |
| 35 | #include <sys/nlookup.h> |
| 36 | #include <sys/fcntl.h> |
| 37 | #include <sys/vnode.h> |
| 38 | #include <sys/linker.h> |
| 39 | #include <machine/elf.h> |
| 40 | |
| 41 | #include <vm/vm.h> |
| 42 | #include <vm/vm_param.h> |
| 43 | #include <vm/vm_zone.h> |
| 44 | #include <sys/lock.h> |
| 45 | #ifdef SPARSE_MAPPING |
| 46 | #include <vm/vm_object.h> |
| 47 | #include <vm/vm_kern.h> |
| 48 | #include <vm/vm_extern.h> |
| 49 | #endif |
| 50 | #include <vm/pmap.h> |
| 51 | #include <vm/vm_map.h> |
| 52 | |
| 53 | static int link_elf_load_module(const char*, linker_file_t*); |
| 54 | static int link_elf_load_file(const char*, linker_file_t*); |
| 55 | static int link_elf_lookup_symbol(linker_file_t, const char*, |
| 56 | c_linker_sym_t*); |
| 57 | static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); |
| 58 | static int link_elf_search_symbol(linker_file_t, caddr_t value, |
| 59 | c_linker_sym_t* sym, long* diffp); |
| 60 | |
| 61 | static void link_elf_unload_file(linker_file_t); |
| 62 | static void link_elf_unload_module(linker_file_t); |
| 63 | static int link_elf_lookup_set(linker_file_t, const char *, |
| 64 | void ***, void ***, int *); |
| 65 | |
| 66 | static struct linker_class_ops link_elf_class_ops = { |
| 67 | link_elf_load_module, |
| 68 | }; |
| 69 | |
| 70 | static struct linker_file_ops link_elf_file_ops = { |
| 71 | link_elf_lookup_symbol, |
| 72 | link_elf_symbol_values, |
| 73 | link_elf_search_symbol, |
| 74 | link_elf_unload_file, |
| 75 | link_elf_lookup_set |
| 76 | }; |
| 77 | |
| 78 | static struct linker_file_ops link_elf_module_ops = { |
| 79 | link_elf_lookup_symbol, |
| 80 | link_elf_symbol_values, |
| 81 | link_elf_search_symbol, |
| 82 | link_elf_unload_module, |
| 83 | link_elf_lookup_set |
| 84 | }; |
| 85 | |
| 86 | typedef struct elf_file { |
| 87 | caddr_t address; /* Relocation address */ |
| 88 | #ifdef SPARSE_MAPPING |
| 89 | vm_object_t object; /* VM object to hold file pages */ |
| 90 | #endif |
| 91 | const Elf_Dyn* dynamic; /* Symbol table etc. */ |
| 92 | Elf_Off nbuckets; /* DT_HASH info */ |
| 93 | Elf_Off nchains; |
| 94 | const Elf_Off* buckets; |
| 95 | const Elf_Off* chains; |
| 96 | caddr_t hash; |
| 97 | caddr_t strtab; /* DT_STRTAB */ |
| 98 | int strsz; /* DT_STRSZ */ |
| 99 | const Elf_Sym* symtab; /* DT_SYMTAB */ |
| 100 | Elf_Addr* got; /* DT_PLTGOT */ |
| 101 | const Elf_Rel* pltrel; /* DT_JMPREL */ |
| 102 | int pltrelsize; /* DT_PLTRELSZ */ |
| 103 | const Elf_Rela* pltrela; /* DT_JMPREL */ |
| 104 | int pltrelasize; /* DT_PLTRELSZ */ |
| 105 | const Elf_Rel* rel; /* DT_REL */ |
| 106 | int relsize; /* DT_RELSZ */ |
| 107 | const Elf_Rela* rela; /* DT_RELA */ |
| 108 | int relasize; /* DT_RELASZ */ |
| 109 | caddr_t modptr; |
| 110 | const 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 | caddr_t symbase; /* malloc'ed symbold base */ |
| 115 | caddr_t strbase; /* malloc'ed string base */ |
| 116 | } *elf_file_t; |
| 117 | |
| 118 | static int parse_dynamic(linker_file_t lf); |
| 119 | static int load_dependancies(linker_file_t lf); |
| 120 | static int relocate_file(linker_file_t lf); |
| 121 | static int parse_module_symbols(linker_file_t lf); |
| 122 | |
| 123 | /* |
| 124 | * The kernel symbol table starts here. |
| 125 | */ |
| 126 | extern struct _dynamic _DYNAMIC; |
| 127 | |
| 128 | static void |
| 129 | link_elf_init(void* arg) |
| 130 | { |
| 131 | Elf_Dyn *dp; |
| 132 | caddr_t modptr, baseptr, sizeptr; |
| 133 | elf_file_t ef; |
| 134 | char *modname; |
| 135 | |
| 136 | #if ELF_TARG_CLASS == ELFCLASS32 |
| 137 | linker_add_class("elf32", NULL, &link_elf_class_ops); |
| 138 | #else |
| 139 | linker_add_class("elf64", NULL, &link_elf_class_ops); |
| 140 | #endif |
| 141 | |
| 142 | dp = (Elf_Dyn*) &_DYNAMIC; |
| 143 | if (dp) { |
| 144 | ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_INTWAIT | M_ZERO); |
| 145 | ef->address = 0; |
| 146 | #ifdef SPARSE_MAPPING |
| 147 | ef->object = 0; |
| 148 | #endif |
| 149 | ef->dynamic = dp; |
| 150 | modname = NULL; |
| 151 | modptr = preload_search_by_type("elf kernel"); |
| 152 | if (modptr) |
| 153 | modname = (char *)preload_search_info(modptr, MODINFO_NAME); |
| 154 | if (modname == NULL) |
| 155 | modname = "kernel"; |
| 156 | linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops); |
| 157 | if (linker_kernel_file == NULL) |
| 158 | panic("link_elf_init: Can't create linker structures for kernel"); |
| 159 | parse_dynamic(linker_kernel_file); |
| 160 | linker_kernel_file->address = (caddr_t) KERNBASE; |
| 161 | linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; |
| 162 | |
| 163 | if (modptr) { |
| 164 | ef->modptr = modptr; |
| 165 | baseptr = preload_search_info(modptr, MODINFO_ADDR); |
| 166 | if (baseptr) |
| 167 | linker_kernel_file->address = *(caddr_t *)baseptr; |
| 168 | sizeptr = preload_search_info(modptr, MODINFO_SIZE); |
| 169 | if (sizeptr) |
| 170 | linker_kernel_file->size = *(size_t *)sizeptr; |
| 171 | } |
| 172 | parse_module_symbols(linker_kernel_file); |
| 173 | linker_current_file = linker_kernel_file; |
| 174 | linker_kernel_file->flags |= LINKER_FILE_LINKED; |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); |
| 179 | |
| 180 | static int |
| 181 | parse_module_symbols(linker_file_t lf) |
| 182 | { |
| 183 | elf_file_t ef = lf->priv; |
| 184 | caddr_t pointer; |
| 185 | caddr_t ssym, esym, base; |
| 186 | caddr_t strtab; |
| 187 | int strcnt; |
| 188 | Elf_Sym* symtab; |
| 189 | int symcnt; |
| 190 | |
| 191 | if (ef->modptr == NULL) |
| 192 | return 0; |
| 193 | pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); |
| 194 | if (pointer == NULL) |
| 195 | return 0; |
| 196 | ssym = *(caddr_t *)pointer; |
| 197 | pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); |
| 198 | if (pointer == NULL) |
| 199 | return 0; |
| 200 | esym = *(caddr_t *)pointer; |
| 201 | |
| 202 | base = ssym; |
| 203 | |
| 204 | symcnt = *(long *)base; |
| 205 | base += sizeof(long); |
| 206 | symtab = (Elf_Sym *)base; |
| 207 | base += roundup(symcnt, sizeof(long)); |
| 208 | |
| 209 | if (base > esym || base < ssym) { |
| 210 | printf("Symbols are corrupt!\n"); |
| 211 | return EINVAL; |
| 212 | } |
| 213 | |
| 214 | strcnt = *(long *)base; |
| 215 | base += sizeof(long); |
| 216 | strtab = base; |
| 217 | base += roundup(strcnt, sizeof(long)); |
| 218 | |
| 219 | if (base > esym || base < ssym) { |
| 220 | printf("Symbols are corrupt!\n"); |
| 221 | return EINVAL; |
| 222 | } |
| 223 | |
| 224 | ef->ddbsymtab = symtab; |
| 225 | ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); |
| 226 | ef->ddbstrtab = strtab; |
| 227 | ef->ddbstrcnt = strcnt; |
| 228 | |
| 229 | return 0; |
| 230 | } |
| 231 | |
| 232 | static int |
| 233 | parse_dynamic(linker_file_t lf) |
| 234 | { |
| 235 | elf_file_t ef = lf->priv; |
| 236 | const Elf_Dyn *dp; |
| 237 | int plttype = DT_REL; |
| 238 | |
| 239 | for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { |
| 240 | switch (dp->d_tag) { |
| 241 | case DT_HASH: |
| 242 | { |
| 243 | /* From src/libexec/rtld-elf/rtld.c */ |
| 244 | const Elf_Off *hashtab = (const Elf_Off *) |
| 245 | (ef->address + dp->d_un.d_ptr); |
| 246 | ef->nbuckets = hashtab[0]; |
| 247 | ef->nchains = hashtab[1]; |
| 248 | ef->buckets = hashtab + 2; |
| 249 | ef->chains = ef->buckets + ef->nbuckets; |
| 250 | break; |
| 251 | } |
| 252 | case DT_STRTAB: |
| 253 | ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); |
| 254 | break; |
| 255 | case DT_STRSZ: |
| 256 | ef->strsz = dp->d_un.d_val; |
| 257 | break; |
| 258 | case DT_SYMTAB: |
| 259 | ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); |
| 260 | break; |
| 261 | case DT_SYMENT: |
| 262 | if (dp->d_un.d_val != sizeof(Elf_Sym)) |
| 263 | return ENOEXEC; |
| 264 | break; |
| 265 | case DT_PLTGOT: |
| 266 | ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); |
| 267 | break; |
| 268 | case DT_REL: |
| 269 | ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); |
| 270 | break; |
| 271 | case DT_RELSZ: |
| 272 | ef->relsize = dp->d_un.d_val; |
| 273 | break; |
| 274 | case DT_RELENT: |
| 275 | if (dp->d_un.d_val != sizeof(Elf_Rel)) |
| 276 | return ENOEXEC; |
| 277 | break; |
| 278 | case DT_JMPREL: |
| 279 | ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); |
| 280 | break; |
| 281 | case DT_PLTRELSZ: |
| 282 | ef->pltrelsize = dp->d_un.d_val; |
| 283 | break; |
| 284 | case DT_RELA: |
| 285 | ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); |
| 286 | break; |
| 287 | case DT_RELASZ: |
| 288 | ef->relasize = dp->d_un.d_val; |
| 289 | break; |
| 290 | case DT_RELAENT: |
| 291 | if (dp->d_un.d_val != sizeof(Elf_Rela)) |
| 292 | return ENOEXEC; |
| 293 | break; |
| 294 | case DT_PLTREL: |
| 295 | plttype = dp->d_un.d_val; |
| 296 | if (plttype != DT_REL && plttype != DT_RELA) |
| 297 | return ENOEXEC; |
| 298 | break; |
| 299 | } |
| 300 | } |
| 301 | |
| 302 | if (plttype == DT_RELA) { |
| 303 | ef->pltrela = (const Elf_Rela *) ef->pltrel; |
| 304 | ef->pltrel = NULL; |
| 305 | ef->pltrelasize = ef->pltrelsize; |
| 306 | ef->pltrelsize = 0; |
| 307 | } |
| 308 | |
| 309 | ef->ddbsymtab = ef->symtab; |
| 310 | ef->ddbsymcnt = ef->nchains; |
| 311 | ef->ddbstrtab = ef->strtab; |
| 312 | ef->ddbstrcnt = ef->strsz; |
| 313 | |
| 314 | return 0; |
| 315 | } |
| 316 | |
| 317 | static void |
| 318 | link_elf_error(const char *s) |
| 319 | { |
| 320 | printf("kldload: %s\n", s); |
| 321 | } |
| 322 | |
| 323 | static int |
| 324 | link_elf_load_module(const char *filename, linker_file_t *result) |
| 325 | { |
| 326 | caddr_t modptr, baseptr, sizeptr, dynptr; |
| 327 | char *type; |
| 328 | elf_file_t ef; |
| 329 | linker_file_t lf; |
| 330 | int error; |
| 331 | vm_offset_t dp; |
| 332 | |
| 333 | /* |
| 334 | * Look to see if we have the module preloaded. |
| 335 | */ |
| 336 | modptr = preload_search_by_name(filename); |
| 337 | if (modptr == NULL) |
| 338 | return (link_elf_load_file(filename, result)); |
| 339 | |
| 340 | /* It's preloaded, check we can handle it and collect information */ |
| 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 | dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); |
| 345 | if (type == NULL || strcmp(type, "elf module") != 0) |
| 346 | return (EFTYPE); |
| 347 | if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) |
| 348 | return (EINVAL); |
| 349 | |
| 350 | ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO); |
| 351 | if (ef == NULL) |
| 352 | return (ENOMEM); |
| 353 | ef->modptr = modptr; |
| 354 | ef->address = *(caddr_t *)baseptr; |
| 355 | #ifdef SPARSE_MAPPING |
| 356 | ef->object = 0; |
| 357 | #endif |
| 358 | dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; |
| 359 | ef->dynamic = (Elf_Dyn *)dp; |
| 360 | lf = linker_make_file(filename, ef, &link_elf_module_ops); |
| 361 | if (lf == NULL) { |
| 362 | kfree(ef, M_LINKER); |
| 363 | return ENOMEM; |
| 364 | } |
| 365 | lf->address = ef->address; |
| 366 | lf->size = *(size_t *)sizeptr; |
| 367 | |
| 368 | error = parse_dynamic(lf); |
| 369 | if (error) { |
| 370 | linker_file_unload(lf); |
| 371 | return error; |
| 372 | } |
| 373 | error = load_dependancies(lf); |
| 374 | if (error) { |
| 375 | linker_file_unload(lf); |
| 376 | return error; |
| 377 | } |
| 378 | error = relocate_file(lf); |
| 379 | if (error) { |
| 380 | linker_file_unload(lf); |
| 381 | return error; |
| 382 | } |
| 383 | parse_module_symbols(lf); |
| 384 | lf->flags |= LINKER_FILE_LINKED; |
| 385 | *result = lf; |
| 386 | return (0); |
| 387 | } |
| 388 | |
| 389 | static int |
| 390 | link_elf_load_file(const char* filename, linker_file_t* result) |
| 391 | { |
| 392 | struct nlookupdata nd; |
| 393 | struct thread *td = curthread; /* XXX */ |
| 394 | struct proc *p = td->td_proc; |
| 395 | struct vnode *vp; |
| 396 | Elf_Ehdr *hdr; |
| 397 | caddr_t firstpage; |
| 398 | int nbytes, i; |
| 399 | Elf_Phdr *phdr; |
| 400 | Elf_Phdr *phlimit; |
| 401 | Elf_Phdr *segs[2]; |
| 402 | int nsegs; |
| 403 | Elf_Phdr *phdyn; |
| 404 | Elf_Phdr *phphdr; |
| 405 | caddr_t mapbase; |
| 406 | size_t mapsize; |
| 407 | Elf_Off base_offset; |
| 408 | Elf_Addr base_vaddr; |
| 409 | Elf_Addr base_vlimit; |
| 410 | int error = 0; |
| 411 | int resid; |
| 412 | elf_file_t ef; |
| 413 | linker_file_t lf; |
| 414 | char *pathname; |
| 415 | Elf_Shdr *shdr; |
| 416 | int symtabindex; |
| 417 | int symstrindex; |
| 418 | int symcnt; |
| 419 | int strcnt; |
| 420 | |
| 421 | KKASSERT(p != NULL); |
| 422 | if (p->p_ucred == NULL) { |
| 423 | printf("link_elf_load_file: cannot load '%s' from filesystem" |
| 424 | " this early\n", filename); |
| 425 | return ENOENT; |
| 426 | } |
| 427 | shdr = NULL; |
| 428 | lf = NULL; |
| 429 | pathname = linker_search_path(filename); |
| 430 | if (pathname == NULL) |
| 431 | return ENOENT; |
| 432 | |
| 433 | error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP); |
| 434 | if (error == 0) |
| 435 | error = vn_open(&nd, NULL, FREAD, 0); |
| 436 | kfree(pathname, M_LINKER); |
| 437 | if (error) { |
| 438 | nlookup_done(&nd); |
| 439 | return error; |
| 440 | } |
| 441 | vp = nd.nl_open_vp; |
| 442 | nd.nl_open_vp = NULL; |
| 443 | nlookup_done(&nd); |
| 444 | |
| 445 | /* |
| 446 | * Read the elf header from the file. |
| 447 | */ |
| 448 | firstpage = kmalloc(PAGE_SIZE, M_LINKER, M_WAITOK); |
| 449 | if (firstpage == NULL) { |
| 450 | error = ENOMEM; |
| 451 | goto out; |
| 452 | } |
| 453 | hdr = (Elf_Ehdr *)firstpage; |
| 454 | error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0, |
| 455 | UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid); |
| 456 | nbytes = PAGE_SIZE - resid; |
| 457 | if (error) |
| 458 | goto out; |
| 459 | |
| 460 | if (!IS_ELF(*hdr)) { |
| 461 | error = ENOEXEC; |
| 462 | goto out; |
| 463 | } |
| 464 | |
| 465 | if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS |
| 466 | || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { |
| 467 | link_elf_error("Unsupported file layout"); |
| 468 | error = ENOEXEC; |
| 469 | goto out; |
| 470 | } |
| 471 | if (hdr->e_ident[EI_VERSION] != EV_CURRENT |
| 472 | || hdr->e_version != EV_CURRENT) { |
| 473 | link_elf_error("Unsupported file version"); |
| 474 | error = ENOEXEC; |
| 475 | goto out; |
| 476 | } |
| 477 | if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { |
| 478 | link_elf_error("Unsupported file type"); |
| 479 | error = ENOEXEC; |
| 480 | goto out; |
| 481 | } |
| 482 | if (hdr->e_machine != ELF_TARG_MACH) { |
| 483 | link_elf_error("Unsupported machine"); |
| 484 | error = ENOEXEC; |
| 485 | goto out; |
| 486 | } |
| 487 | |
| 488 | /* |
| 489 | * We rely on the program header being in the first page. This is |
| 490 | * not strictly required by the ABI specification, but it seems to |
| 491 | * always true in practice. And, it simplifies things considerably. |
| 492 | */ |
| 493 | if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && |
| 494 | (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && |
| 495 | (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) |
| 496 | link_elf_error("Unreadable program headers"); |
| 497 | |
| 498 | /* |
| 499 | * Scan the program header entries, and save key information. |
| 500 | * |
| 501 | * We rely on there being exactly two load segments, text and data, |
| 502 | * in that order. |
| 503 | */ |
| 504 | phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); |
| 505 | phlimit = phdr + hdr->e_phnum; |
| 506 | nsegs = 0; |
| 507 | phdyn = NULL; |
| 508 | phphdr = NULL; |
| 509 | while (phdr < phlimit) { |
| 510 | switch (phdr->p_type) { |
| 511 | |
| 512 | case PT_LOAD: |
| 513 | if (nsegs == 2) { |
| 514 | link_elf_error("Too many sections"); |
| 515 | error = ENOEXEC; |
| 516 | goto out; |
| 517 | } |
| 518 | segs[nsegs] = phdr; |
| 519 | ++nsegs; |
| 520 | break; |
| 521 | |
| 522 | case PT_PHDR: |
| 523 | phphdr = phdr; |
| 524 | break; |
| 525 | |
| 526 | case PT_DYNAMIC: |
| 527 | phdyn = phdr; |
| 528 | break; |
| 529 | } |
| 530 | |
| 531 | ++phdr; |
| 532 | } |
| 533 | if (phdyn == NULL) { |
| 534 | link_elf_error("Object is not dynamically-linked"); |
| 535 | error = ENOEXEC; |
| 536 | goto out; |
| 537 | } |
| 538 | |
| 539 | /* |
| 540 | * Allocate the entire address space of the object, to stake out our |
| 541 | * contiguous region, and to establish the base address for relocation. |
| 542 | */ |
| 543 | base_offset = trunc_page(segs[0]->p_offset); |
| 544 | base_vaddr = trunc_page(segs[0]->p_vaddr); |
| 545 | base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); |
| 546 | mapsize = base_vlimit - base_vaddr; |
| 547 | |
| 548 | ef = kmalloc(sizeof(struct elf_file), M_LINKER, M_WAITOK | M_ZERO); |
| 549 | #ifdef SPARSE_MAPPING |
| 550 | ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); |
| 551 | if (ef->object == NULL) { |
| 552 | kfree(ef, M_LINKER); |
| 553 | error = ENOMEM; |
| 554 | goto out; |
| 555 | } |
| 556 | vm_object_reference(ef->object); |
| 557 | ef->address = (caddr_t) vm_map_min(kernel_map); |
| 558 | error = vm_map_find(kernel_map, ef->object, 0, |
| 559 | (vm_offset_t *)&ef->address, mapsize, |
| 560 | 1, |
| 561 | VM_MAPTYPE_NORMAL, |
| 562 | VM_PROT_ALL, VM_PROT_ALL, |
| 563 | 0); |
| 564 | if (error) { |
| 565 | vm_object_deallocate(ef->object); |
| 566 | kfree(ef, M_LINKER); |
| 567 | goto out; |
| 568 | } |
| 569 | #else |
| 570 | ef->address = kmalloc(mapsize, M_LINKER, M_WAITOK); |
| 571 | #endif |
| 572 | mapbase = ef->address; |
| 573 | |
| 574 | /* |
| 575 | * Read the text and data sections and zero the bss. |
| 576 | */ |
| 577 | for (i = 0; i < 2; i++) { |
| 578 | caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; |
| 579 | error = vn_rdwr(UIO_READ, vp, |
| 580 | segbase, segs[i]->p_filesz, segs[i]->p_offset, |
| 581 | UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid); |
| 582 | if (error) { |
| 583 | #ifdef SPARSE_MAPPING |
| 584 | vm_map_remove(kernel_map, (vm_offset_t) ef->address, |
| 585 | (vm_offset_t) ef->address |
| 586 | + (ef->object->size << PAGE_SHIFT)); |
| 587 | vm_object_deallocate(ef->object); |
| 588 | #else |
| 589 | kfree(ef->address, M_LINKER); |
| 590 | #endif |
| 591 | kfree(ef, M_LINKER); |
| 592 | goto out; |
| 593 | } |
| 594 | bzero(segbase + segs[i]->p_filesz, |
| 595 | segs[i]->p_memsz - segs[i]->p_filesz); |
| 596 | |
| 597 | #ifdef SPARSE_MAPPING |
| 598 | /* |
| 599 | * Wire down the pages |
| 600 | */ |
| 601 | vm_map_wire(kernel_map, |
| 602 | (vm_offset_t) segbase, |
| 603 | (vm_offset_t) segbase + segs[i]->p_memsz, |
| 604 | 0); |
| 605 | #endif |
| 606 | } |
| 607 | |
| 608 | ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); |
| 609 | |
| 610 | lf = linker_make_file(filename, ef, &link_elf_file_ops); |
| 611 | if (lf == NULL) { |
| 612 | #ifdef SPARSE_MAPPING |
| 613 | vm_map_remove(kernel_map, (vm_offset_t) ef->address, |
| 614 | (vm_offset_t) ef->address |
| 615 | + (ef->object->size << PAGE_SHIFT)); |
| 616 | vm_object_deallocate(ef->object); |
| 617 | #else |
| 618 | kfree(ef->address, M_LINKER); |
| 619 | #endif |
| 620 | kfree(ef, M_LINKER); |
| 621 | error = ENOMEM; |
| 622 | goto out; |
| 623 | } |
| 624 | lf->address = ef->address; |
| 625 | lf->size = mapsize; |
| 626 | |
| 627 | error = parse_dynamic(lf); |
| 628 | if (error) |
| 629 | goto out; |
| 630 | error = load_dependancies(lf); |
| 631 | if (error) |
| 632 | goto out; |
| 633 | error = relocate_file(lf); |
| 634 | if (error) |
| 635 | goto out; |
| 636 | |
| 637 | /* Try and load the symbol table if it's present. (you can strip it!) */ |
| 638 | nbytes = hdr->e_shnum * hdr->e_shentsize; |
| 639 | if (nbytes == 0 || hdr->e_shoff == 0) |
| 640 | goto nosyms; |
| 641 | shdr = kmalloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); |
| 642 | if (shdr == NULL) { |
| 643 | error = ENOMEM; |
| 644 | goto out; |
| 645 | } |
| 646 | error = vn_rdwr(UIO_READ, vp, |
| 647 | (caddr_t)shdr, nbytes, hdr->e_shoff, |
| 648 | UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid); |
| 649 | if (error) |
| 650 | goto out; |
| 651 | symtabindex = -1; |
| 652 | symstrindex = -1; |
| 653 | for (i = 0; i < hdr->e_shnum; i++) { |
| 654 | if (shdr[i].sh_type == SHT_SYMTAB) { |
| 655 | symtabindex = i; |
| 656 | symstrindex = shdr[i].sh_link; |
| 657 | } |
| 658 | } |
| 659 | if (symtabindex < 0 || symstrindex < 0) |
| 660 | goto nosyms; |
| 661 | |
| 662 | symcnt = shdr[symtabindex].sh_size; |
| 663 | ef->symbase = kmalloc(symcnt, M_LINKER, M_WAITOK); |
| 664 | strcnt = shdr[symstrindex].sh_size; |
| 665 | ef->strbase = kmalloc(strcnt, M_LINKER, M_WAITOK); |
| 666 | |
| 667 | if (ef->symbase == NULL || ef->strbase == NULL) { |
| 668 | error = ENOMEM; |
| 669 | goto out; |
| 670 | } |
| 671 | error = vn_rdwr(UIO_READ, vp, |
| 672 | ef->symbase, symcnt, shdr[symtabindex].sh_offset, |
| 673 | UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid); |
| 674 | if (error) |
| 675 | goto out; |
| 676 | error = vn_rdwr(UIO_READ, vp, |
| 677 | ef->strbase, strcnt, shdr[symstrindex].sh_offset, |
| 678 | UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid); |
| 679 | if (error) |
| 680 | goto out; |
| 681 | |
| 682 | ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); |
| 683 | ef->ddbsymtab = (const Elf_Sym *)ef->symbase; |
| 684 | ef->ddbstrcnt = strcnt; |
| 685 | ef->ddbstrtab = ef->strbase; |
| 686 | |
| 687 | lf->flags |= LINKER_FILE_LINKED; |
| 688 | |
| 689 | nosyms: |
| 690 | |
| 691 | *result = lf; |
| 692 | |
| 693 | out: |
| 694 | if (error && lf) |
| 695 | linker_file_unload(lf); |
| 696 | if (shdr) |
| 697 | kfree(shdr, M_LINKER); |
| 698 | if (firstpage) |
| 699 | kfree(firstpage, M_LINKER); |
| 700 | vn_unlock(vp); |
| 701 | vn_close(vp, FREAD); |
| 702 | |
| 703 | return error; |
| 704 | } |
| 705 | |
| 706 | static void |
| 707 | link_elf_unload_file(linker_file_t file) |
| 708 | { |
| 709 | elf_file_t ef = file->priv; |
| 710 | |
| 711 | if (ef) { |
| 712 | #ifdef SPARSE_MAPPING |
| 713 | if (ef->object) { |
| 714 | vm_map_remove(kernel_map, (vm_offset_t) ef->address, |
| 715 | (vm_offset_t) ef->address |
| 716 | + (ef->object->size << PAGE_SHIFT)); |
| 717 | vm_object_deallocate(ef->object); |
| 718 | } |
| 719 | #else |
| 720 | if (ef->address) |
| 721 | kfree(ef->address, M_LINKER); |
| 722 | #endif |
| 723 | if (ef->symbase) |
| 724 | kfree(ef->symbase, M_LINKER); |
| 725 | if (ef->strbase) |
| 726 | kfree(ef->strbase, M_LINKER); |
| 727 | kfree(ef, M_LINKER); |
| 728 | } |
| 729 | } |
| 730 | |
| 731 | static void |
| 732 | link_elf_unload_module(linker_file_t file) |
| 733 | { |
| 734 | elf_file_t ef = file->priv; |
| 735 | |
| 736 | if (ef) |
| 737 | kfree(ef, M_LINKER); |
| 738 | if (file->filename) |
| 739 | preload_delete_name(file->filename); |
| 740 | } |
| 741 | |
| 742 | static int |
| 743 | load_dependancies(linker_file_t lf) |
| 744 | { |
| 745 | elf_file_t ef = lf->priv; |
| 746 | linker_file_t lfdep; |
| 747 | char* name; |
| 748 | const Elf_Dyn *dp; |
| 749 | int error = 0; |
| 750 | |
| 751 | /* |
| 752 | * All files are dependant on /kernel. |
| 753 | */ |
| 754 | if (linker_kernel_file) { |
| 755 | linker_kernel_file->refs++; |
| 756 | linker_file_add_dependancy(lf, linker_kernel_file); |
| 757 | } |
| 758 | |
| 759 | for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { |
| 760 | if (dp->d_tag == DT_NEEDED) { |
| 761 | name = ef->strtab + dp->d_un.d_val; |
| 762 | |
| 763 | error = linker_load_file(name, &lfdep); |
| 764 | if (error) |
| 765 | goto out; |
| 766 | error = linker_file_add_dependancy(lf, lfdep); |
| 767 | if (error) |
| 768 | goto out; |
| 769 | } |
| 770 | } |
| 771 | |
| 772 | out: |
| 773 | return error; |
| 774 | } |
| 775 | |
| 776 | static const char * |
| 777 | symbol_name(elf_file_t ef, Elf_Word r_info) |
| 778 | { |
| 779 | const Elf_Sym *ref; |
| 780 | |
| 781 | if (ELF_R_SYM(r_info)) { |
| 782 | ref = ef->symtab + ELF_R_SYM(r_info); |
| 783 | return ef->strtab + ref->st_name; |
| 784 | } else |
| 785 | return NULL; |
| 786 | } |
| 787 | |
| 788 | static int |
| 789 | relocate_file(linker_file_t lf) |
| 790 | { |
| 791 | elf_file_t ef = lf->priv; |
| 792 | const Elf_Rel *rellim; |
| 793 | const Elf_Rel *rel; |
| 794 | const Elf_Rela *relalim; |
| 795 | const Elf_Rela *rela; |
| 796 | const char *symname; |
| 797 | |
| 798 | /* Perform relocations without addend if there are any: */ |
| 799 | rel = ef->rel; |
| 800 | if (rel) { |
| 801 | rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); |
| 802 | while (rel < rellim) { |
| 803 | symname = symbol_name(ef, rel->r_info); |
| 804 | if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { |
| 805 | printf("link_elf: symbol %s undefined\n", symname); |
| 806 | return ENOENT; |
| 807 | } |
| 808 | rel++; |
| 809 | } |
| 810 | } |
| 811 | |
| 812 | /* Perform relocations with addend if there are any: */ |
| 813 | rela = ef->rela; |
| 814 | if (rela) { |
| 815 | relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); |
| 816 | while (rela < relalim) { |
| 817 | symname = symbol_name(ef, rela->r_info); |
| 818 | if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { |
| 819 | printf("link_elf: symbol %s undefined\n", symname); |
| 820 | return ENOENT; |
| 821 | } |
| 822 | rela++; |
| 823 | } |
| 824 | } |
| 825 | |
| 826 | /* Perform PLT relocations without addend if there are any: */ |
| 827 | rel = ef->pltrel; |
| 828 | if (rel) { |
| 829 | rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); |
| 830 | while (rel < rellim) { |
| 831 | symname = symbol_name(ef, rel->r_info); |
| 832 | if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { |
| 833 | printf("link_elf: symbol %s undefined\n", symname); |
| 834 | return ENOENT; |
| 835 | } |
| 836 | rel++; |
| 837 | } |
| 838 | } |
| 839 | |
| 840 | /* Perform relocations with addend if there are any: */ |
| 841 | rela = ef->pltrela; |
| 842 | if (rela) { |
| 843 | relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); |
| 844 | while (rela < relalim) { |
| 845 | symname = symbol_name(ef, rela->r_info); |
| 846 | if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { |
| 847 | printf("link_elf: symbol %s undefined\n", symname); |
| 848 | return ENOENT; |
| 849 | } |
| 850 | rela++; |
| 851 | } |
| 852 | } |
| 853 | |
| 854 | return 0; |
| 855 | } |
| 856 | |
| 857 | /* |
| 858 | * Hash function for symbol table lookup. Don't even think about changing |
| 859 | * this. It is specified by the System V ABI. |
| 860 | */ |
| 861 | static unsigned long |
| 862 | elf_hash(const char *name) |
| 863 | { |
| 864 | const unsigned char *p = (const unsigned char *) name; |
| 865 | unsigned long h = 0; |
| 866 | unsigned long g; |
| 867 | |
| 868 | while (*p != '\0') { |
| 869 | h = (h << 4) + *p++; |
| 870 | if ((g = h & 0xf0000000) != 0) |
| 871 | h ^= g >> 24; |
| 872 | h &= ~g; |
| 873 | } |
| 874 | return h; |
| 875 | } |
| 876 | |
| 877 | int |
| 878 | link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) |
| 879 | { |
| 880 | elf_file_t ef = lf->priv; |
| 881 | unsigned long symnum; |
| 882 | const Elf_Sym* symp; |
| 883 | const char *strp; |
| 884 | unsigned long hash; |
| 885 | int i; |
| 886 | |
| 887 | /* First, search hashed global symbols */ |
| 888 | hash = elf_hash(name); |
| 889 | symnum = ef->buckets[hash % ef->nbuckets]; |
| 890 | |
| 891 | while (symnum != STN_UNDEF) { |
| 892 | if (symnum >= ef->nchains) { |
| 893 | printf("link_elf_lookup_symbol: corrupt symbol table\n"); |
| 894 | return ENOENT; |
| 895 | } |
| 896 | |
| 897 | symp = ef->symtab + symnum; |
| 898 | if (symp->st_name == 0) { |
| 899 | printf("link_elf_lookup_symbol: corrupt symbol table\n"); |
| 900 | return ENOENT; |
| 901 | } |
| 902 | |
| 903 | strp = ef->strtab + symp->st_name; |
| 904 | |
| 905 | if (strcmp(name, strp) == 0) { |
| 906 | if (symp->st_shndx != SHN_UNDEF || |
| 907 | (symp->st_value != 0 && |
| 908 | ELF_ST_TYPE(symp->st_info) == STT_FUNC) |
| 909 | ) { |
| 910 | *sym = (c_linker_sym_t) symp; |
| 911 | return 0; |
| 912 | } else { |
| 913 | return ENOENT; |
| 914 | } |
| 915 | } |
| 916 | |
| 917 | symnum = ef->chains[symnum]; |
| 918 | } |
| 919 | |
| 920 | /* If we have not found it, look at the full table (if loaded) */ |
| 921 | if (ef->symtab == ef->ddbsymtab) |
| 922 | return ENOENT; |
| 923 | |
| 924 | /* Exhaustive search */ |
| 925 | for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { |
| 926 | strp = ef->ddbstrtab + symp->st_name; |
| 927 | if (strcmp(name, strp) == 0) { |
| 928 | if (symp->st_shndx != SHN_UNDEF || |
| 929 | (symp->st_value != 0 && |
| 930 | ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { |
| 931 | *sym = (c_linker_sym_t) symp; |
| 932 | return 0; |
| 933 | } else { |
| 934 | return ENOENT; |
| 935 | } |
| 936 | } |
| 937 | } |
| 938 | return ENOENT; |
| 939 | } |
| 940 | |
| 941 | static int |
| 942 | link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) |
| 943 | { |
| 944 | elf_file_t ef = lf->priv; |
| 945 | const Elf_Sym* es = (const Elf_Sym*) sym; |
| 946 | |
| 947 | if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { |
| 948 | symval->name = ef->strtab + es->st_name; |
| 949 | symval->value = (caddr_t) ef->address + es->st_value; |
| 950 | symval->size = es->st_size; |
| 951 | return 0; |
| 952 | } |
| 953 | if (ef->symtab == ef->ddbsymtab) |
| 954 | return ENOENT; |
| 955 | if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { |
| 956 | symval->name = ef->ddbstrtab + es->st_name; |
| 957 | symval->value = (caddr_t) ef->address + es->st_value; |
| 958 | symval->size = es->st_size; |
| 959 | return 0; |
| 960 | } |
| 961 | return ENOENT; |
| 962 | } |
| 963 | |
| 964 | static int |
| 965 | link_elf_search_symbol(linker_file_t lf, caddr_t value, |
| 966 | c_linker_sym_t* sym, long* diffp) |
| 967 | { |
| 968 | elf_file_t ef = lf->priv; |
| 969 | u_long off = (uintptr_t) (void *) value; |
| 970 | u_long diff = off; |
| 971 | u_long st_value; |
| 972 | const Elf_Sym* es; |
| 973 | const Elf_Sym* best = 0; |
| 974 | int i; |
| 975 | |
| 976 | for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { |
| 977 | if (es->st_name == 0) |
| 978 | continue; |
| 979 | st_value = es->st_value + (uintptr_t) (void *) ef->address; |
| 980 | if (off >= st_value) { |
| 981 | if (off - st_value < diff) { |
| 982 | diff = off - st_value; |
| 983 | best = es; |
| 984 | if (diff == 0) |
| 985 | break; |
| 986 | } else if (off - st_value == diff) { |
| 987 | best = es; |
| 988 | } |
| 989 | } |
| 990 | } |
| 991 | if (best == 0) |
| 992 | *diffp = off; |
| 993 | else |
| 994 | *diffp = diff; |
| 995 | *sym = (c_linker_sym_t) best; |
| 996 | |
| 997 | return 0; |
| 998 | } |
| 999 | |
| 1000 | /* |
| 1001 | * Look up a linker set on an ELF system. |
| 1002 | */ |
| 1003 | static int |
| 1004 | link_elf_lookup_set(linker_file_t lf, const char *name, |
| 1005 | void ***startp, void ***stopp, int *countp) |
| 1006 | { |
| 1007 | c_linker_sym_t sym; |
| 1008 | linker_symval_t symval; |
| 1009 | char *setsym; |
| 1010 | void **start, **stop; |
| 1011 | int len, error = 0, count; |
| 1012 | |
| 1013 | len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ |
| 1014 | setsym = kmalloc(len, M_LINKER, M_WAITOK); |
| 1015 | if (setsym == NULL) |
| 1016 | return ENOMEM; |
| 1017 | |
| 1018 | /* get address of first entry */ |
| 1019 | ksnprintf(setsym, len, "%s%s", "__start_set_", name); |
| 1020 | error = link_elf_lookup_symbol(lf, setsym, &sym); |
| 1021 | if (error) |
| 1022 | goto out; |
| 1023 | link_elf_symbol_values(lf, sym, &symval); |
| 1024 | if (symval.value == 0) { |
| 1025 | error = ESRCH; |
| 1026 | goto out; |
| 1027 | } |
| 1028 | start = (void **)symval.value; |
| 1029 | |
| 1030 | /* get address of last entry */ |
| 1031 | ksnprintf(setsym, len, "%s%s", "__stop_set_", name); |
| 1032 | error = link_elf_lookup_symbol(lf, setsym, &sym); |
| 1033 | if (error) |
| 1034 | goto out; |
| 1035 | link_elf_symbol_values(lf, sym, &symval); |
| 1036 | if (symval.value == 0) { |
| 1037 | error = ESRCH; |
| 1038 | goto out; |
| 1039 | } |
| 1040 | stop = (void **)symval.value; |
| 1041 | |
| 1042 | /* and the number of entries */ |
| 1043 | count = stop - start; |
| 1044 | |
| 1045 | /* and copy out */ |
| 1046 | if (startp) |
| 1047 | *startp = start; |
| 1048 | if (stopp) |
| 1049 | *stopp = stop; |
| 1050 | if (countp) |
| 1051 | *countp = count; |
| 1052 | |
| 1053 | out: |
| 1054 | kfree(setsym, M_LINKER); |
| 1055 | return error; |
| 1056 | } |
| 1057 | |