1 /*- 2 * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org> 3 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> 4 * Copyright (c) 1998 Peter Wemm <peter@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD: src/sys/boot/common/load_elf_obj.c,v 1.2 2005/12/18 04:52:35 marcel Exp $ 29 */ 30 31 #include <sys/param.h> 32 #include <sys/exec.h> 33 #include <sys/linker.h> 34 #include <sys/module.h> 35 #include <inttypes.h> 36 #include <string.h> 37 #include <machine/elf.h> 38 #include <stand.h> 39 #define FREEBSD_ELF 40 #include <link.h> 41 42 #include "bootstrap.h" 43 44 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l) 45 46 #if defined(__i386__) && __ELF_WORD_SIZE == 64 47 #undef ELF_TARG_CLASS 48 #undef ELF_TARG_MACH 49 #define ELF_TARG_CLASS ELFCLASS64 50 #define ELF_TARG_MACH EM_X86_64 51 #endif 52 53 typedef struct elf_file { 54 Elf_Ehdr hdr; 55 Elf_Shdr *e_shdr; 56 57 int symtabindex; /* Index of symbol table */ 58 int shstrindex; /* Index of section name string table */ 59 60 int fd; 61 vm_offset_t off; 62 } *elf_file_t; 63 64 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef, 65 u_int64_t loadaddr); 66 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef, 67 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp); 68 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, 69 Elf_Addr p, void *val, size_t len); 70 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp, 71 elf_file_t ef); 72 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx); 73 74 const char *__elfN(obj_kerneltype) = "elf kernel"; 75 const char *__elfN(obj_moduletype) = "elf obj module"; 76 77 /* 78 * Attempt to load the file (file) as an ELF module. It will be stored at 79 * (dest), and a pointer to a module structure describing the loaded object 80 * will be saved in (result). 81 */ 82 int 83 __elfN(obj_loadfile)(char *filename, u_int64_t dest, 84 struct preloaded_file **result) 85 { 86 struct preloaded_file *fp, *kfp; 87 struct elf_file ef; 88 Elf_Ehdr *hdr; 89 int err; 90 ssize_t bytes_read; 91 92 fp = NULL; 93 bzero(&ef, sizeof(struct elf_file)); 94 95 /* 96 * Open the image, read and validate the ELF header 97 */ 98 if (filename == NULL) /* can't handle nameless */ 99 return(EFTYPE); 100 if ((ef.fd = rel_open(filename, NULL, O_RDONLY)) == -1) 101 return(errno); 102 103 hdr = &ef.hdr; 104 bytes_read = read(ef.fd, hdr, sizeof(*hdr)); 105 if (bytes_read != sizeof(*hdr)) { 106 err = EFTYPE; /* could be EIO, but may be small file */ 107 goto oerr; 108 } 109 110 /* Is it ELF? */ 111 if (!IS_ELF(*hdr)) { 112 err = EFTYPE; 113 goto oerr; 114 } 115 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */ 116 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 117 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */ 118 hdr->e_version != EV_CURRENT || 119 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */ 120 hdr->e_type != ET_REL) { 121 err = EFTYPE; 122 goto oerr; 123 } 124 125 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 || 126 hdr->e_shentsize != sizeof(Elf_Shdr)) { 127 err = EFTYPE; 128 goto oerr; 129 } 130 131 kfp = file_findfile(NULL, NULL); 132 if (kfp == NULL) { 133 printf("elf" __XSTRING(__ELF_WORD_SIZE) 134 "_obj_loadfile: can't load module before kernel\n"); 135 err = EPERM; 136 goto oerr; 137 } 138 if (strcmp(__elfN(obj_kerneltype), kfp->f_type)) { 139 printf("elf" __XSTRING(__ELF_WORD_SIZE) 140 "_obj_loadfile: can't load module with kernel type '%s'\n", 141 kfp->f_type); 142 err = EPERM; 143 goto oerr; 144 } 145 146 /* Page-align the load address */ 147 dest = roundup(dest, PAGE_SIZE); 148 149 /* 150 * Ok, we think we should handle this. 151 */ 152 fp = file_alloc(); 153 if (fp == NULL) { 154 printf("elf" __XSTRING(__ELF_WORD_SIZE) 155 "_obj_loadfile: cannot allocate module info\n"); 156 err = EPERM; 157 goto out; 158 } 159 fp->f_name = rel_rootpath(filename); 160 fp->f_type = strdup(__elfN(obj_moduletype)); 161 162 printf("%s ", filename); 163 164 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); 165 if (fp->f_size == 0 || fp->f_addr == 0) 166 goto ioerr; 167 168 /* save exec header as metadata */ 169 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); 170 171 /* Load OK, return module pointer */ 172 *result = (struct preloaded_file *)fp; 173 err = 0; 174 goto out; 175 176 ioerr: 177 err = EIO; 178 oerr: 179 file_discard(fp); 180 out: 181 close(ef.fd); 182 if (ef.e_shdr != NULL) 183 free(ef.e_shdr); 184 185 return(err); 186 } 187 188 /* 189 * With the file (fd) open on the image, and (ehdr) containing 190 * the Elf header, load the image at (off) 191 */ 192 static int 193 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off) 194 { 195 Elf_Ehdr *hdr; 196 Elf_Shdr *shdr; 197 vm_offset_t firstaddr, lastaddr; 198 int i, nsym, res, ret, shdrbytes, symstrindex; 199 200 ret = 0; 201 firstaddr = lastaddr = (vm_offset_t)off; 202 hdr = &ef->hdr; 203 ef->off = (vm_offset_t)off; 204 205 /* Read in the section headers. */ 206 shdrbytes = hdr->e_shnum * hdr->e_shentsize; 207 shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes); 208 if (shdr == NULL) { 209 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 210 "_obj_loadimage: read section headers failed\n"); 211 goto out; 212 } 213 ef->e_shdr = shdr; 214 215 /* 216 * Decide where to load everything, but don't read it yet. 217 * We store the load address as a non-zero sh_addr value. 218 * Start with the code/data and bss. 219 */ 220 for (i = 0; i < hdr->e_shnum; i++) { 221 shdr[i].sh_addr = 0; 222 if (shdr[i].sh_size == 0) 223 continue; 224 switch (shdr[i].sh_type) { 225 case SHT_PROGBITS: 226 case SHT_NOBITS: 227 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 228 shdr[i].sh_addr = (Elf_Addr)lastaddr; 229 lastaddr += shdr[i].sh_size; 230 break; 231 } 232 } 233 234 /* Symbols. */ 235 nsym = 0; 236 for (i = 0; i < hdr->e_shnum; i++) { 237 switch (shdr[i].sh_type) { 238 case SHT_SYMTAB: 239 nsym++; 240 ef->symtabindex = i; 241 shdr[i].sh_addr = (Elf_Addr)lastaddr; 242 lastaddr += shdr[i].sh_size; 243 break; 244 } 245 } 246 if (nsym != 1) { 247 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 248 "_obj_loadimage: file has no valid symbol table\n"); 249 goto out; 250 } 251 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); 252 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; 253 lastaddr += shdr[ef->symtabindex].sh_size; 254 255 symstrindex = shdr[ef->symtabindex].sh_link; 256 if (symstrindex < 0 || symstrindex >= hdr->e_shnum || 257 shdr[symstrindex].sh_type != SHT_STRTAB) { 258 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 259 "_obj_loadimage: file has invalid symbol strings\n"); 260 goto out; 261 } 262 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); 263 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; 264 lastaddr += shdr[symstrindex].sh_size; 265 266 /* Section names. */ 267 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || 268 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 269 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 270 "_obj_loadimage: file has no section names\n"); 271 goto out; 272 } 273 ef->shstrindex = hdr->e_shstrndx; 274 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); 275 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; 276 lastaddr += shdr[ef->shstrindex].sh_size; 277 278 /* Relocation tables. */ 279 for (i = 0; i < hdr->e_shnum; i++) { 280 switch (shdr[i].sh_type) { 281 case SHT_REL: 282 case SHT_RELA: 283 lastaddr = roundup(lastaddr, shdr[i].sh_addralign); 284 shdr[i].sh_addr = (Elf_Addr)lastaddr; 285 lastaddr += shdr[i].sh_size; 286 break; 287 } 288 } 289 290 /* Clear the whole area, including bss regions. */ 291 kern_bzero(firstaddr, lastaddr - firstaddr); 292 293 /* Now read it all in. */ 294 for (i = 0; i < hdr->e_shnum; i++) { 295 if (shdr[i].sh_addr == 0 || shdr[i].sh_type == SHT_NOBITS) 296 continue; 297 if (kern_pread(ef->fd, (vm_offset_t)shdr[i].sh_addr, 298 shdr[i].sh_size, (off_t)shdr[i].sh_offset) != 0) { 299 printf("\nelf" __XSTRING(__ELF_WORD_SIZE) 300 "_obj_loadimage: read failed\n"); 301 goto out; 302 } 303 } 304 305 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); 306 307 res = __elfN(obj_parse_modmetadata)(fp, ef); 308 if (res != 0) 309 goto out; 310 311 ret = lastaddr - firstaddr; 312 fp->f_addr = firstaddr; 313 314 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); 315 316 out: 317 printf("\n"); 318 return ret; 319 } 320 321 #if defined(__i386__) && __ELF_WORD_SIZE == 64 322 struct mod_metadata64 { 323 int md_version; /* structure version MDTV_* */ 324 int md_type; /* type of entry MDT_* */ 325 u_int64_t md_data; /* specific data */ 326 u_int64_t md_cval; /* common string label */ 327 }; 328 #endif 329 330 int 331 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) 332 { 333 struct mod_metadata md; 334 #if defined(__i386__) && __ELF_WORD_SIZE == 64 335 struct mod_metadata64 md64; 336 #endif 337 struct mod_depend *mdepend; 338 struct mod_version mver; 339 char *s; 340 int error, modcnt, minfolen; 341 Elf_Addr v, p, p_stop; 342 343 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, 344 &modcnt) != 0) 345 return ENOENT; 346 347 modcnt = 0; 348 while (p < p_stop) { 349 COPYOUT(p, &v, sizeof(v)); 350 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); 351 if (error != 0) 352 return (error); 353 #if defined(__i386__) && __ELF_WORD_SIZE == 64 354 COPYOUT(v, &md64, sizeof(md64)); 355 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); 356 if (error != 0) 357 return (error); 358 md.md_version = md64.md_version; 359 md.md_type = md64.md_type; 360 md.md_cval = (const char *)(uintptr_t)md64.md_cval; 361 md.md_data = (void *)(uintptr_t)md64.md_data; 362 #else 363 COPYOUT(v, &md, sizeof(md)); 364 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); 365 if (error != 0) 366 return (error); 367 #endif 368 p += sizeof(Elf_Addr); 369 switch(md.md_type) { 370 case MDT_DEPEND: 371 s = strdupout((vm_offset_t)md.md_cval); 372 minfolen = sizeof(*mdepend) + strlen(s) + 1; 373 mdepend = malloc(minfolen); 374 if (mdepend == NULL) 375 return ENOMEM; 376 COPYOUT((vm_offset_t)md.md_data, mdepend, 377 sizeof(*mdepend)); 378 strcpy((char*)(mdepend + 1), s); 379 free(s); 380 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, 381 mdepend); 382 free(mdepend); 383 break; 384 case MDT_VERSION: 385 s = strdupout((vm_offset_t)md.md_cval); 386 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); 387 file_addmodule(fp, s, mver.mv_version, NULL); 388 free(s); 389 modcnt++; 390 break; 391 case MDT_MODULE: 392 break; 393 default: 394 printf("unknown type %d\n", md.md_type); 395 break; 396 } 397 } 398 return 0; 399 } 400 401 static int 402 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef, 403 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) 404 { 405 Elf_Ehdr *hdr; 406 Elf_Shdr *shdr; 407 char *p; 408 vm_offset_t shstrtab; 409 int i; 410 411 hdr = &ef->hdr; 412 shdr = ef->e_shdr; 413 shstrtab = shdr[ef->shstrindex].sh_addr; 414 415 for (i = 0; i < hdr->e_shnum; i++) { 416 if (shdr[i].sh_type != SHT_PROGBITS) 417 continue; 418 if (shdr[i].sh_name == 0) 419 continue; 420 p = strdupout(shstrtab + shdr[i].sh_name); 421 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { 422 *startp = shdr[i].sh_addr; 423 *stopp = shdr[i].sh_addr + shdr[i].sh_size; 424 *countp = (*stopp - *startp) / sizeof(Elf_Addr); 425 free(p); 426 return (0); 427 } 428 free(p); 429 } 430 431 return (ESRCH); 432 } 433 434 /* 435 * Apply any intra-module relocations to the value. p is the load address 436 * of the value and val/len is the value to be modified. This does NOT modify 437 * the image in-place, because this is done by kern_linker later on. 438 */ 439 static int 440 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, 441 void *val, size_t len) 442 { 443 Elf_Ehdr *hdr; 444 Elf_Shdr *shdr; 445 Elf_Addr off = p; 446 Elf_Addr base; 447 Elf_Rela a, *abase; 448 Elf_Rel r, *rbase; 449 int error, i, j, nrel, nrela; 450 451 hdr = &ef->hdr; 452 shdr = ef->e_shdr; 453 454 for (i = 0; i < hdr->e_shnum; i++) { 455 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) 456 continue; 457 base = shdr[shdr[i].sh_info].sh_addr; 458 if (base == 0 || shdr[i].sh_addr == 0) 459 continue; 460 if (off < base || off + len > base + 461 shdr[shdr[i].sh_info].sh_size) 462 continue; 463 464 switch (shdr[i].sh_type) { 465 case SHT_RELA: 466 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; 467 468 nrela = shdr[i].sh_size / sizeof(Elf_Rela); 469 for (j = 0; j < nrela; j++) { 470 COPYOUT(abase + j, &a, sizeof(a)); 471 472 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 473 &a, ELF_RELOC_RELA, base, off, val, len); 474 if (error != 0) 475 return (error); 476 } 477 break; 478 case SHT_REL: 479 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; 480 481 nrel = shdr[i].sh_size / sizeof(Elf_Rel); 482 for (j = 0; j < nrel; j++) { 483 COPYOUT(rbase + j, &r, sizeof(r)); 484 485 error = __elfN(reloc)(ef, __elfN(obj_symaddr), 486 &r, ELF_RELOC_REL, base, off, val, len); 487 if (error != 0) 488 return (error); 489 } 490 break; 491 } 492 } 493 return (0); 494 } 495 496 /* Look up the address of a specified symbol. */ 497 static Elf_Addr 498 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) 499 { 500 Elf_Sym sym; 501 Elf_Addr base; 502 503 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) 504 return (0); 505 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), 506 &sym, sizeof(sym)); 507 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) 508 return (0); 509 base = ef->e_shdr[sym.st_shndx].sh_addr; 510 if (base == 0) 511 return (0); 512 return (base + sym.st_value); 513 } 514