1 /* Postprocess module symbol versions 2 * 3 * Copyright 2003 Kai Germaschewski 4 * Copyright 2002-2004 Rusty Russell, IBM Corporation 5 * Copyright 2006 Sam Ravnborg 6 * Based in part on module-init-tools/depmod.c,file2alias 7 * 8 * This software may be used and distributed according to the terms 9 * of the GNU General Public License, incorporated herein by reference. 10 * 11 * Usage: modpost vmlinux module1.o module2.o ... 12 */ 13 14 #include <ctype.h> 15 #include "modpost.h" 16 #include "../../include/linux/license.h" 17 18 /* Are we using CONFIG_MODVERSIONS? */ 19 int modversions = 0; 20 /* Warn about undefined symbols? (do so if we have vmlinux) */ 21 int have_vmlinux = 0; 22 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ 23 static int all_versions = 0; 24 /* If we are modposting external module set to 1 */ 25 static int external_module = 0; 26 /* How a symbol is exported */ 27 enum export {export_plain, export_gpl, export_gpl_future, export_unknown}; 28 29 void fatal(const char *fmt, ...) 30 { 31 va_list arglist; 32 33 fprintf(stderr, "FATAL: "); 34 35 va_start(arglist, fmt); 36 vfprintf(stderr, fmt, arglist); 37 va_end(arglist); 38 39 exit(1); 40 } 41 42 void warn(const char *fmt, ...) 43 { 44 va_list arglist; 45 46 fprintf(stderr, "WARNING: "); 47 48 va_start(arglist, fmt); 49 vfprintf(stderr, fmt, arglist); 50 va_end(arglist); 51 } 52 53 static int is_vmlinux(const char *modname) 54 { 55 const char *myname; 56 57 if ((myname = strrchr(modname, '/'))) 58 myname++; 59 else 60 myname = modname; 61 62 return strcmp(myname, "vmlinux") == 0; 63 } 64 65 void *do_nofail(void *ptr, const char *expr) 66 { 67 if (!ptr) { 68 fatal("modpost: Memory allocation failure: %s.\n", expr); 69 } 70 return ptr; 71 } 72 73 /* A list of all modules we processed */ 74 75 static struct module *modules; 76 77 static struct module *find_module(char *modname) 78 { 79 struct module *mod; 80 81 for (mod = modules; mod; mod = mod->next) 82 if (strcmp(mod->name, modname) == 0) 83 break; 84 return mod; 85 } 86 87 static struct module *new_module(char *modname) 88 { 89 struct module *mod; 90 char *p, *s; 91 92 mod = NOFAIL(malloc(sizeof(*mod))); 93 memset(mod, 0, sizeof(*mod)); 94 p = NOFAIL(strdup(modname)); 95 96 /* strip trailing .o */ 97 if ((s = strrchr(p, '.')) != NULL) 98 if (strcmp(s, ".o") == 0) 99 *s = '\0'; 100 101 /* add to list */ 102 mod->name = p; 103 mod->gpl_compatible = -1; 104 mod->next = modules; 105 modules = mod; 106 107 return mod; 108 } 109 110 /* A hash of all exported symbols, 111 * struct symbol is also used for lists of unresolved symbols */ 112 113 #define SYMBOL_HASH_SIZE 1024 114 115 struct symbol { 116 struct symbol *next; 117 struct module *module; 118 unsigned int crc; 119 int crc_valid; 120 unsigned int weak:1; 121 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ 122 unsigned int kernel:1; /* 1 if symbol is from kernel 123 * (only for external modules) **/ 124 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */ 125 enum export export; /* Type of export */ 126 char name[0]; 127 }; 128 129 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 130 131 /* This is based on the hash agorithm from gdbm, via tdb */ 132 static inline unsigned int tdb_hash(const char *name) 133 { 134 unsigned value; /* Used to compute the hash value. */ 135 unsigned i; /* Used to cycle through random values. */ 136 137 /* Set the initial value from the key size. */ 138 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++) 139 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 140 141 return (1103515243 * value + 12345); 142 } 143 144 /** 145 * Allocate a new symbols for use in the hash of exported symbols or 146 * the list of unresolved symbols per module 147 **/ 148 static struct symbol *alloc_symbol(const char *name, unsigned int weak, 149 struct symbol *next) 150 { 151 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 152 153 memset(s, 0, sizeof(*s)); 154 strcpy(s->name, name); 155 s->weak = weak; 156 s->next = next; 157 return s; 158 } 159 160 /* For the hash of exported symbols */ 161 static struct symbol *new_symbol(const char *name, struct module *module, 162 enum export export) 163 { 164 unsigned int hash; 165 struct symbol *new; 166 167 hash = tdb_hash(name) % SYMBOL_HASH_SIZE; 168 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); 169 new->module = module; 170 new->export = export; 171 return new; 172 } 173 174 static struct symbol *find_symbol(const char *name) 175 { 176 struct symbol *s; 177 178 /* For our purposes, .foo matches foo. PPC64 needs this. */ 179 if (name[0] == '.') 180 name++; 181 182 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) { 183 if (strcmp(s->name, name) == 0) 184 return s; 185 } 186 return NULL; 187 } 188 189 static struct { 190 const char *str; 191 enum export export; 192 } export_list[] = { 193 { .str = "EXPORT_SYMBOL", .export = export_plain }, 194 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl }, 195 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future }, 196 { .str = "(unknown)", .export = export_unknown }, 197 }; 198 199 200 static const char *export_str(enum export ex) 201 { 202 return export_list[ex].str; 203 } 204 205 static enum export export_no(const char * s) 206 { 207 int i; 208 for (i = 0; export_list[i].export != export_unknown; i++) { 209 if (strcmp(export_list[i].str, s) == 0) 210 return export_list[i].export; 211 } 212 return export_unknown; 213 } 214 215 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec) 216 { 217 if (sec == elf->export_sec) 218 return export_plain; 219 else if (sec == elf->export_gpl_sec) 220 return export_gpl; 221 else if (sec == elf->export_gpl_future_sec) 222 return export_gpl_future; 223 else 224 return export_unknown; 225 } 226 227 /** 228 * Add an exported symbol - it may have already been added without a 229 * CRC, in this case just update the CRC 230 **/ 231 static struct symbol *sym_add_exported(const char *name, struct module *mod, 232 enum export export) 233 { 234 struct symbol *s = find_symbol(name); 235 236 if (!s) { 237 s = new_symbol(name, mod, export); 238 } else { 239 if (!s->preloaded) { 240 warn("%s: '%s' exported twice. Previous export " 241 "was in %s%s\n", mod->name, name, 242 s->module->name, 243 is_vmlinux(s->module->name) ?"":".ko"); 244 } 245 } 246 s->preloaded = 0; 247 s->vmlinux = is_vmlinux(mod->name); 248 s->kernel = 0; 249 s->export = export; 250 return s; 251 } 252 253 static void sym_update_crc(const char *name, struct module *mod, 254 unsigned int crc, enum export export) 255 { 256 struct symbol *s = find_symbol(name); 257 258 if (!s) 259 s = new_symbol(name, mod, export); 260 s->crc = crc; 261 s->crc_valid = 1; 262 } 263 264 void *grab_file(const char *filename, unsigned long *size) 265 { 266 struct stat st; 267 void *map; 268 int fd; 269 270 fd = open(filename, O_RDONLY); 271 if (fd < 0 || fstat(fd, &st) != 0) 272 return NULL; 273 274 *size = st.st_size; 275 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 276 close(fd); 277 278 if (map == MAP_FAILED) 279 return NULL; 280 return map; 281 } 282 283 /** 284 * Return a copy of the next line in a mmap'ed file. 285 * spaces in the beginning of the line is trimmed away. 286 * Return a pointer to a static buffer. 287 **/ 288 char* get_next_line(unsigned long *pos, void *file, unsigned long size) 289 { 290 static char line[4096]; 291 int skip = 1; 292 size_t len = 0; 293 signed char *p = (signed char *)file + *pos; 294 char *s = line; 295 296 for (; *pos < size ; (*pos)++) 297 { 298 if (skip && isspace(*p)) { 299 p++; 300 continue; 301 } 302 skip = 0; 303 if (*p != '\n' && (*pos < size)) { 304 len++; 305 *s++ = *p++; 306 if (len > 4095) 307 break; /* Too long, stop */ 308 } else { 309 /* End of string */ 310 *s = '\0'; 311 return line; 312 } 313 } 314 /* End of buffer */ 315 return NULL; 316 } 317 318 void release_file(void *file, unsigned long size) 319 { 320 munmap(file, size); 321 } 322 323 static void parse_elf(struct elf_info *info, const char *filename) 324 { 325 unsigned int i; 326 Elf_Ehdr *hdr = info->hdr; 327 Elf_Shdr *sechdrs; 328 Elf_Sym *sym; 329 330 hdr = grab_file(filename, &info->size); 331 if (!hdr) { 332 perror(filename); 333 exit(1); 334 } 335 info->hdr = hdr; 336 if (info->size < sizeof(*hdr)) 337 goto truncated; 338 339 /* Fix endianness in ELF header */ 340 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 341 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 342 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 343 hdr->e_machine = TO_NATIVE(hdr->e_machine); 344 sechdrs = (void *)hdr + hdr->e_shoff; 345 info->sechdrs = sechdrs; 346 347 /* Fix endianness in section headers */ 348 for (i = 0; i < hdr->e_shnum; i++) { 349 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 350 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 351 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 352 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 353 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 354 } 355 /* Find symbol table. */ 356 for (i = 1; i < hdr->e_shnum; i++) { 357 const char *secstrings 358 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 359 const char *secname; 360 361 if (sechdrs[i].sh_offset > info->size) 362 goto truncated; 363 secname = secstrings + sechdrs[i].sh_name; 364 if (strcmp(secname, ".modinfo") == 0) { 365 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 366 info->modinfo_len = sechdrs[i].sh_size; 367 } else if (strcmp(secname, "__ksymtab") == 0) 368 info->export_sec = i; 369 else if (strcmp(secname, "__ksymtab_gpl") == 0) 370 info->export_gpl_sec = i; 371 else if (strcmp(secname, "__ksymtab_gpl_future") == 0) 372 info->export_gpl_future_sec = i; 373 374 if (sechdrs[i].sh_type != SHT_SYMTAB) 375 continue; 376 377 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; 378 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset 379 + sechdrs[i].sh_size; 380 info->strtab = (void *)hdr + 381 sechdrs[sechdrs[i].sh_link].sh_offset; 382 } 383 if (!info->symtab_start) { 384 fatal("%s has no symtab?\n", filename); 385 } 386 /* Fix endianness in symbols */ 387 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 388 sym->st_shndx = TO_NATIVE(sym->st_shndx); 389 sym->st_name = TO_NATIVE(sym->st_name); 390 sym->st_value = TO_NATIVE(sym->st_value); 391 sym->st_size = TO_NATIVE(sym->st_size); 392 } 393 return; 394 395 truncated: 396 fatal("%s is truncated.\n", filename); 397 } 398 399 static void parse_elf_finish(struct elf_info *info) 400 { 401 release_file(info->hdr, info->size); 402 } 403 404 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_" 405 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_" 406 407 static void handle_modversions(struct module *mod, struct elf_info *info, 408 Elf_Sym *sym, const char *symname) 409 { 410 unsigned int crc; 411 enum export export = export_from_sec(info, sym->st_shndx); 412 413 switch (sym->st_shndx) { 414 case SHN_COMMON: 415 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 416 break; 417 case SHN_ABS: 418 /* CRC'd symbol */ 419 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) { 420 crc = (unsigned int) sym->st_value; 421 sym_update_crc(symname + strlen(CRC_PFX), mod, crc, 422 export); 423 } 424 break; 425 case SHN_UNDEF: 426 /* undefined symbol */ 427 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 428 ELF_ST_BIND(sym->st_info) != STB_WEAK) 429 break; 430 /* ignore global offset table */ 431 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 432 break; 433 /* ignore __this_module, it will be resolved shortly */ 434 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0) 435 break; 436 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ 437 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) 438 /* add compatibility with older glibc */ 439 #ifndef STT_SPARC_REGISTER 440 #define STT_SPARC_REGISTER STT_REGISTER 441 #endif 442 if (info->hdr->e_machine == EM_SPARC || 443 info->hdr->e_machine == EM_SPARCV9) { 444 /* Ignore register directives. */ 445 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 446 break; 447 if (symname[0] == '.') { 448 char *munged = strdup(symname); 449 munged[0] = '_'; 450 munged[1] = toupper(munged[1]); 451 symname = munged; 452 } 453 } 454 #endif 455 456 if (memcmp(symname, MODULE_SYMBOL_PREFIX, 457 strlen(MODULE_SYMBOL_PREFIX)) == 0) 458 mod->unres = alloc_symbol(symname + 459 strlen(MODULE_SYMBOL_PREFIX), 460 ELF_ST_BIND(sym->st_info) == STB_WEAK, 461 mod->unres); 462 break; 463 default: 464 /* All exported symbols */ 465 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) { 466 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod, 467 export); 468 } 469 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0) 470 mod->has_init = 1; 471 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0) 472 mod->has_cleanup = 1; 473 break; 474 } 475 } 476 477 /** 478 * Parse tag=value strings from .modinfo section 479 **/ 480 static char *next_string(char *string, unsigned long *secsize) 481 { 482 /* Skip non-zero chars */ 483 while (string[0]) { 484 string++; 485 if ((*secsize)-- <= 1) 486 return NULL; 487 } 488 489 /* Skip any zero padding. */ 490 while (!string[0]) { 491 string++; 492 if ((*secsize)-- <= 1) 493 return NULL; 494 } 495 return string; 496 } 497 498 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len, 499 const char *tag, char *info) 500 { 501 char *p; 502 unsigned int taglen = strlen(tag); 503 unsigned long size = modinfo_len; 504 505 if (info) { 506 size -= info - (char *)modinfo; 507 modinfo = next_string(info, &size); 508 } 509 510 for (p = modinfo; p; p = next_string(p, &size)) { 511 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 512 return p + taglen + 1; 513 } 514 return NULL; 515 } 516 517 static char *get_modinfo(void *modinfo, unsigned long modinfo_len, 518 const char *tag) 519 520 { 521 return get_next_modinfo(modinfo, modinfo_len, tag, NULL); 522 } 523 524 /** 525 * Test if string s ends in string sub 526 * return 0 if match 527 **/ 528 static int strrcmp(const char *s, const char *sub) 529 { 530 int slen, sublen; 531 532 if (!s || !sub) 533 return 1; 534 535 slen = strlen(s); 536 sublen = strlen(sub); 537 538 if ((slen == 0) || (sublen == 0)) 539 return 1; 540 541 if (sublen > slen) 542 return 1; 543 544 return memcmp(s + slen - sublen, sub, sublen); 545 } 546 547 /** 548 * Whitelist to allow certain references to pass with no warning. 549 * Pattern 1: 550 * If a module parameter is declared __initdata and permissions=0 551 * then this is legal despite the warning generated. 552 * We cannot see value of permissions here, so just ignore 553 * this pattern. 554 * The pattern is identified by: 555 * tosec = .init.data 556 * fromsec = .data* 557 * atsym =__param* 558 * 559 * Pattern 2: 560 * Many drivers utilise a *driver container with references to 561 * add, remove, probe functions etc. 562 * These functions may often be marked __init and we do not want to 563 * warn here. 564 * the pattern is identified by: 565 * tosec = .init.text | .exit.text | .init.data 566 * fromsec = .data 567 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one 568 **/ 569 static int secref_whitelist(const char *tosec, const char *fromsec, 570 const char *atsym) 571 { 572 int f1 = 1, f2 = 1; 573 const char **s; 574 const char *pat2sym[] = { 575 "driver", 576 "_template", /* scsi uses *_template a lot */ 577 "_sht", /* scsi also used *_sht to some extent */ 578 "_ops", 579 "_probe", 580 "_probe_one", 581 NULL 582 }; 583 584 /* Check for pattern 1 */ 585 if (strcmp(tosec, ".init.data") != 0) 586 f1 = 0; 587 if (strncmp(fromsec, ".data", strlen(".data")) != 0) 588 f1 = 0; 589 if (strncmp(atsym, "__param", strlen("__param")) != 0) 590 f1 = 0; 591 592 if (f1) 593 return f1; 594 595 /* Check for pattern 2 */ 596 if ((strcmp(tosec, ".init.text") != 0) && 597 (strcmp(tosec, ".exit.text") != 0) && 598 (strcmp(tosec, ".init.data") != 0)) 599 f2 = 0; 600 if (strcmp(fromsec, ".data") != 0) 601 f2 = 0; 602 603 for (s = pat2sym; *s; s++) 604 if (strrcmp(atsym, *s) == 0) 605 f1 = 1; 606 607 return f1 && f2; 608 } 609 610 /** 611 * Find symbol based on relocation record info. 612 * In some cases the symbol supplied is a valid symbol so 613 * return refsym. If st_name != 0 we assume this is a valid symbol. 614 * In other cases the symbol needs to be looked up in the symbol table 615 * based on section and address. 616 * **/ 617 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr, 618 Elf_Sym *relsym) 619 { 620 Elf_Sym *sym; 621 622 if (relsym->st_name != 0) 623 return relsym; 624 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 625 if (sym->st_shndx != relsym->st_shndx) 626 continue; 627 if (sym->st_value == addr) 628 return sym; 629 } 630 return NULL; 631 } 632 633 /* 634 * Find symbols before or equal addr and after addr - in the section sec. 635 * If we find two symbols with equal offset prefer one with a valid name. 636 * The ELF format may have a better way to detect what type of symbol 637 * it is, but this works for now. 638 **/ 639 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr, 640 const char *sec, 641 Elf_Sym **before, Elf_Sym **after) 642 { 643 Elf_Sym *sym; 644 Elf_Ehdr *hdr = elf->hdr; 645 Elf_Addr beforediff = ~0; 646 Elf_Addr afterdiff = ~0; 647 const char *secstrings = (void *)hdr + 648 elf->sechdrs[hdr->e_shstrndx].sh_offset; 649 650 *before = NULL; 651 *after = NULL; 652 653 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 654 const char *symsec; 655 656 if (sym->st_shndx >= SHN_LORESERVE) 657 continue; 658 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name; 659 if (strcmp(symsec, sec) != 0) 660 continue; 661 if (sym->st_value <= addr) { 662 if ((addr - sym->st_value) < beforediff) { 663 beforediff = addr - sym->st_value; 664 *before = sym; 665 } 666 else if ((addr - sym->st_value) == beforediff) { 667 /* equal offset, valid name? */ 668 const char *name = elf->strtab + sym->st_name; 669 if (name && strlen(name)) 670 *before = sym; 671 } 672 } 673 else 674 { 675 if ((sym->st_value - addr) < afterdiff) { 676 afterdiff = sym->st_value - addr; 677 *after = sym; 678 } 679 else if ((sym->st_value - addr) == afterdiff) { 680 /* equal offset, valid name? */ 681 const char *name = elf->strtab + sym->st_name; 682 if (name && strlen(name)) 683 *after = sym; 684 } 685 } 686 } 687 } 688 689 /** 690 * Print a warning about a section mismatch. 691 * Try to find symbols near it so user can find it. 692 * Check whitelist before warning - it may be a false positive. 693 **/ 694 static void warn_sec_mismatch(const char *modname, const char *fromsec, 695 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r) 696 { 697 const char *refsymname = ""; 698 Elf_Sym *before, *after; 699 Elf_Sym *refsym; 700 Elf_Ehdr *hdr = elf->hdr; 701 Elf_Shdr *sechdrs = elf->sechdrs; 702 const char *secstrings = (void *)hdr + 703 sechdrs[hdr->e_shstrndx].sh_offset; 704 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name; 705 706 find_symbols_between(elf, r.r_offset, fromsec, &before, &after); 707 708 refsym = find_elf_symbol(elf, r.r_addend, sym); 709 if (refsym && strlen(elf->strtab + refsym->st_name)) 710 refsymname = elf->strtab + refsym->st_name; 711 712 /* check whitelist - we may ignore it */ 713 if (before && 714 secref_whitelist(secname, fromsec, elf->strtab + before->st_name)) 715 return; 716 717 if (before && after) { 718 warn("%s - Section mismatch: reference to %s:%s from %s " 719 "between '%s' (at offset 0x%llx) and '%s'\n", 720 modname, secname, refsymname, fromsec, 721 elf->strtab + before->st_name, 722 (long long)r.r_offset, 723 elf->strtab + after->st_name); 724 } else if (before) { 725 warn("%s - Section mismatch: reference to %s:%s from %s " 726 "after '%s' (at offset 0x%llx)\n", 727 modname, secname, refsymname, fromsec, 728 elf->strtab + before->st_name, 729 (long long)r.r_offset); 730 } else if (after) { 731 warn("%s - Section mismatch: reference to %s:%s from %s " 732 "before '%s' (at offset -0x%llx)\n", 733 modname, secname, refsymname, fromsec, 734 elf->strtab + after->st_name, 735 (long long)r.r_offset); 736 } else { 737 warn("%s - Section mismatch: reference to %s:%s from %s " 738 "(offset 0x%llx)\n", 739 modname, secname, fromsec, refsymname, 740 (long long)r.r_offset); 741 } 742 } 743 744 /** 745 * A module includes a number of sections that are discarded 746 * either when loaded or when used as built-in. 747 * For loaded modules all functions marked __init and all data 748 * marked __initdata will be discarded when the module has been intialized. 749 * Likewise for modules used built-in the sections marked __exit 750 * are discarded because __exit marked function are supposed to be called 751 * only when a moduel is unloaded which never happes for built-in modules. 752 * The check_sec_ref() function traverses all relocation records 753 * to find all references to a section that reference a section that will 754 * be discarded and warns about it. 755 **/ 756 static void check_sec_ref(struct module *mod, const char *modname, 757 struct elf_info *elf, 758 int section(const char*), 759 int section_ref_ok(const char *)) 760 { 761 int i; 762 Elf_Sym *sym; 763 Elf_Ehdr *hdr = elf->hdr; 764 Elf_Shdr *sechdrs = elf->sechdrs; 765 const char *secstrings = (void *)hdr + 766 sechdrs[hdr->e_shstrndx].sh_offset; 767 768 /* Walk through all sections */ 769 for (i = 0; i < hdr->e_shnum; i++) { 770 const char *name = secstrings + sechdrs[i].sh_name; 771 const char *secname; 772 Elf_Rela r; 773 unsigned int r_sym; 774 /* We want to process only relocation sections and not .init */ 775 if (sechdrs[i].sh_type == SHT_RELA) { 776 Elf_Rela *rela; 777 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset; 778 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size; 779 name += strlen(".rela"); 780 if (section_ref_ok(name)) 781 continue; 782 783 for (rela = start; rela < stop; rela++) { 784 r.r_offset = TO_NATIVE(rela->r_offset); 785 #if KERNEL_ELFCLASS == ELFCLASS64 786 if (hdr->e_machine == EM_MIPS) { 787 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 788 r_sym = TO_NATIVE(r_sym); 789 } else { 790 r.r_info = TO_NATIVE(rela->r_info); 791 r_sym = ELF_R_SYM(r.r_info); 792 } 793 #else 794 r.r_info = TO_NATIVE(rela->r_info); 795 r_sym = ELF_R_SYM(r.r_info); 796 #endif 797 r.r_addend = TO_NATIVE(rela->r_addend); 798 sym = elf->symtab_start + r_sym; 799 /* Skip special sections */ 800 if (sym->st_shndx >= SHN_LORESERVE) 801 continue; 802 803 secname = secstrings + 804 sechdrs[sym->st_shndx].sh_name; 805 if (section(secname)) 806 warn_sec_mismatch(modname, name, 807 elf, sym, r); 808 } 809 } else if (sechdrs[i].sh_type == SHT_REL) { 810 Elf_Rel *rel; 811 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset; 812 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size; 813 name += strlen(".rel"); 814 if (section_ref_ok(name)) 815 continue; 816 817 for (rel = start; rel < stop; rel++) { 818 r.r_offset = TO_NATIVE(rel->r_offset); 819 #if KERNEL_ELFCLASS == ELFCLASS64 820 if (hdr->e_machine == EM_MIPS) { 821 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 822 r_sym = TO_NATIVE(r_sym); 823 } else { 824 r.r_info = TO_NATIVE(rel->r_info); 825 r_sym = ELF_R_SYM(r.r_info); 826 } 827 #else 828 r.r_info = TO_NATIVE(rel->r_info); 829 r_sym = ELF_R_SYM(r.r_info); 830 #endif 831 r.r_addend = 0; 832 sym = elf->symtab_start + r_sym; 833 /* Skip special sections */ 834 if (sym->st_shndx >= SHN_LORESERVE) 835 continue; 836 837 secname = secstrings + 838 sechdrs[sym->st_shndx].sh_name; 839 if (section(secname)) 840 warn_sec_mismatch(modname, name, 841 elf, sym, r); 842 } 843 } 844 } 845 } 846 847 /** 848 * Functions used only during module init is marked __init and is stored in 849 * a .init.text section. Likewise data is marked __initdata and stored in 850 * a .init.data section. 851 * If this section is one of these sections return 1 852 * See include/linux/init.h for the details 853 **/ 854 static int init_section(const char *name) 855 { 856 if (strcmp(name, ".init") == 0) 857 return 1; 858 if (strncmp(name, ".init.", strlen(".init.")) == 0) 859 return 1; 860 return 0; 861 } 862 863 /** 864 * Identify sections from which references to a .init section is OK. 865 * 866 * Unfortunately references to read only data that referenced .init 867 * sections had to be excluded. Almost all of these are false 868 * positives, they are created by gcc. The downside of excluding rodata 869 * is that there really are some user references from rodata to 870 * init code, e.g. drivers/video/vgacon.c: 871 * 872 * const struct consw vga_con = { 873 * con_startup: vgacon_startup, 874 * 875 * where vgacon_startup is __init. If you want to wade through the false 876 * positives, take out the check for rodata. 877 **/ 878 static int init_section_ref_ok(const char *name) 879 { 880 const char **s; 881 /* Absolute section names */ 882 const char *namelist1[] = { 883 ".init", 884 ".opd", /* see comment [OPD] at exit_section_ref_ok() */ 885 ".toc1", /* used by ppc64 */ 886 ".stab", 887 ".rodata", 888 ".text.lock", 889 "__bug_table", /* used by powerpc for BUG() */ 890 ".pci_fixup_header", 891 ".pci_fixup_final", 892 ".pdr", 893 "__param", 894 "__ex_table", 895 ".fixup", 896 ".smp_locks", 897 ".plt", /* seen on ARCH=um build on x86_64. Harmless */ 898 NULL 899 }; 900 /* Start of section names */ 901 const char *namelist2[] = { 902 ".init.", 903 ".altinstructions", 904 ".eh_frame", 905 ".debug", 906 NULL 907 }; 908 /* part of section name */ 909 const char *namelist3 [] = { 910 ".unwind", /* sample: IA_64.unwind.init.text */ 911 NULL 912 }; 913 914 for (s = namelist1; *s; s++) 915 if (strcmp(*s, name) == 0) 916 return 1; 917 for (s = namelist2; *s; s++) 918 if (strncmp(*s, name, strlen(*s)) == 0) 919 return 1; 920 for (s = namelist3; *s; s++) 921 if (strstr(name, *s) != NULL) 922 return 1; 923 if (strrcmp(name, ".init") == 0) 924 return 1; 925 return 0; 926 } 927 928 /* 929 * Functions used only during module exit is marked __exit and is stored in 930 * a .exit.text section. Likewise data is marked __exitdata and stored in 931 * a .exit.data section. 932 * If this section is one of these sections return 1 933 * See include/linux/init.h for the details 934 **/ 935 static int exit_section(const char *name) 936 { 937 if (strcmp(name, ".exit.text") == 0) 938 return 1; 939 if (strcmp(name, ".exit.data") == 0) 940 return 1; 941 return 0; 942 943 } 944 945 /* 946 * Identify sections from which references to a .exit section is OK. 947 * 948 * [OPD] Keith Ownes <kaos@sgi.com> commented: 949 * For our future {in}sanity, add a comment that this is the ppc .opd 950 * section, not the ia64 .opd section. 951 * ia64 .opd should not point to discarded sections. 952 * [.rodata] like for .init.text we ignore .rodata references -same reason 953 **/ 954 static int exit_section_ref_ok(const char *name) 955 { 956 const char **s; 957 /* Absolute section names */ 958 const char *namelist1[] = { 959 ".exit.text", 960 ".exit.data", 961 ".init.text", 962 ".rodata", 963 ".opd", /* See comment [OPD] */ 964 ".toc1", /* used by ppc64 */ 965 ".altinstructions", 966 ".pdr", 967 "__bug_table", /* used by powerpc for BUG() */ 968 ".exitcall.exit", 969 ".eh_frame", 970 ".stab", 971 "__ex_table", 972 ".fixup", 973 ".smp_locks", 974 ".plt", /* seen on ARCH=um build on x86_64. Harmless */ 975 NULL 976 }; 977 /* Start of section names */ 978 const char *namelist2[] = { 979 ".debug", 980 NULL 981 }; 982 /* part of section name */ 983 const char *namelist3 [] = { 984 ".unwind", /* Sample: IA_64.unwind.exit.text */ 985 NULL 986 }; 987 988 for (s = namelist1; *s; s++) 989 if (strcmp(*s, name) == 0) 990 return 1; 991 for (s = namelist2; *s; s++) 992 if (strncmp(*s, name, strlen(*s)) == 0) 993 return 1; 994 for (s = namelist3; *s; s++) 995 if (strstr(name, *s) != NULL) 996 return 1; 997 return 0; 998 } 999 1000 static void read_symbols(char *modname) 1001 { 1002 const char *symname; 1003 char *version; 1004 char *license; 1005 struct module *mod; 1006 struct elf_info info = { }; 1007 Elf_Sym *sym; 1008 1009 parse_elf(&info, modname); 1010 1011 mod = new_module(modname); 1012 1013 /* When there's no vmlinux, don't print warnings about 1014 * unresolved symbols (since there'll be too many ;) */ 1015 if (is_vmlinux(modname)) { 1016 have_vmlinux = 1; 1017 mod->skip = 1; 1018 } 1019 1020 license = get_modinfo(info.modinfo, info.modinfo_len, "license"); 1021 while (license) { 1022 if (license_is_gpl_compatible(license)) 1023 mod->gpl_compatible = 1; 1024 else { 1025 mod->gpl_compatible = 0; 1026 break; 1027 } 1028 license = get_next_modinfo(info.modinfo, info.modinfo_len, 1029 "license", license); 1030 } 1031 1032 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 1033 symname = info.strtab + sym->st_name; 1034 1035 handle_modversions(mod, &info, sym, symname); 1036 handle_moddevtable(mod, &info, sym, symname); 1037 } 1038 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok); 1039 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok); 1040 1041 version = get_modinfo(info.modinfo, info.modinfo_len, "version"); 1042 if (version) 1043 maybe_frob_rcs_version(modname, version, info.modinfo, 1044 version - (char *)info.hdr); 1045 if (version || (all_versions && !is_vmlinux(modname))) 1046 get_src_version(modname, mod->srcversion, 1047 sizeof(mod->srcversion)-1); 1048 1049 parse_elf_finish(&info); 1050 1051 /* Our trick to get versioning for struct_module - it's 1052 * never passed as an argument to an exported function, so 1053 * the automatic versioning doesn't pick it up, but it's really 1054 * important anyhow */ 1055 if (modversions) 1056 mod->unres = alloc_symbol("struct_module", 0, mod->unres); 1057 } 1058 1059 #define SZ 500 1060 1061 /* We first write the generated file into memory using the 1062 * following helper, then compare to the file on disk and 1063 * only update the later if anything changed */ 1064 1065 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 1066 const char *fmt, ...) 1067 { 1068 char tmp[SZ]; 1069 int len; 1070 va_list ap; 1071 1072 va_start(ap, fmt); 1073 len = vsnprintf(tmp, SZ, fmt, ap); 1074 buf_write(buf, tmp, len); 1075 va_end(ap); 1076 } 1077 1078 void buf_write(struct buffer *buf, const char *s, int len) 1079 { 1080 if (buf->size - buf->pos < len) { 1081 buf->size += len + SZ; 1082 buf->p = realloc(buf->p, buf->size); 1083 } 1084 strncpy(buf->p + buf->pos, s, len); 1085 buf->pos += len; 1086 } 1087 1088 void check_license(struct module *mod) 1089 { 1090 struct symbol *s, *exp; 1091 1092 for (s = mod->unres; s; s = s->next) { 1093 const char *basename; 1094 if (mod->gpl_compatible == 1) { 1095 /* GPL-compatible modules may use all symbols */ 1096 continue; 1097 } 1098 exp = find_symbol(s->name); 1099 if (!exp || exp->module == mod) 1100 continue; 1101 basename = strrchr(mod->name, '/'); 1102 if (basename) 1103 basename++; 1104 switch (exp->export) { 1105 case export_gpl: 1106 fatal("modpost: GPL-incompatible module %s " 1107 "uses GPL-only symbol '%s'\n", 1108 basename ? basename : mod->name, 1109 exp->name); 1110 break; 1111 case export_gpl_future: 1112 warn("modpost: GPL-incompatible module %s " 1113 "uses future GPL-only symbol '%s'\n", 1114 basename ? basename : mod->name, 1115 exp->name); 1116 break; 1117 case export_plain: /* ignore */ break; 1118 case export_unknown: /* ignore */ break; 1119 } 1120 } 1121 } 1122 1123 /** 1124 * Header for the generated file 1125 **/ 1126 static void add_header(struct buffer *b, struct module *mod) 1127 { 1128 buf_printf(b, "#include <linux/module.h>\n"); 1129 buf_printf(b, "#include <linux/vermagic.h>\n"); 1130 buf_printf(b, "#include <linux/compiler.h>\n"); 1131 buf_printf(b, "\n"); 1132 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 1133 buf_printf(b, "\n"); 1134 buf_printf(b, "struct module __this_module\n"); 1135 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 1136 buf_printf(b, " .name = KBUILD_MODNAME,\n"); 1137 if (mod->has_init) 1138 buf_printf(b, " .init = init_module,\n"); 1139 if (mod->has_cleanup) 1140 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 1141 " .exit = cleanup_module,\n" 1142 "#endif\n"); 1143 buf_printf(b, "};\n"); 1144 } 1145 1146 /** 1147 * Record CRCs for unresolved symbols 1148 **/ 1149 static void add_versions(struct buffer *b, struct module *mod) 1150 { 1151 struct symbol *s, *exp; 1152 1153 for (s = mod->unres; s; s = s->next) { 1154 exp = find_symbol(s->name); 1155 if (!exp || exp->module == mod) { 1156 if (have_vmlinux && !s->weak) 1157 warn("\"%s\" [%s.ko] undefined!\n", 1158 s->name, mod->name); 1159 continue; 1160 } 1161 s->module = exp->module; 1162 s->crc_valid = exp->crc_valid; 1163 s->crc = exp->crc; 1164 } 1165 1166 if (!modversions) 1167 return; 1168 1169 buf_printf(b, "\n"); 1170 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 1171 buf_printf(b, "__attribute_used__\n"); 1172 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 1173 1174 for (s = mod->unres; s; s = s->next) { 1175 if (!s->module) { 1176 continue; 1177 } 1178 if (!s->crc_valid) { 1179 warn("\"%s\" [%s.ko] has no CRC!\n", 1180 s->name, mod->name); 1181 continue; 1182 } 1183 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); 1184 } 1185 1186 buf_printf(b, "};\n"); 1187 } 1188 1189 static void add_depends(struct buffer *b, struct module *mod, 1190 struct module *modules) 1191 { 1192 struct symbol *s; 1193 struct module *m; 1194 int first = 1; 1195 1196 for (m = modules; m; m = m->next) { 1197 m->seen = is_vmlinux(m->name); 1198 } 1199 1200 buf_printf(b, "\n"); 1201 buf_printf(b, "static const char __module_depends[]\n"); 1202 buf_printf(b, "__attribute_used__\n"); 1203 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 1204 buf_printf(b, "\"depends="); 1205 for (s = mod->unres; s; s = s->next) { 1206 if (!s->module) 1207 continue; 1208 1209 if (s->module->seen) 1210 continue; 1211 1212 s->module->seen = 1; 1213 buf_printf(b, "%s%s", first ? "" : ",", 1214 strrchr(s->module->name, '/') + 1); 1215 first = 0; 1216 } 1217 buf_printf(b, "\";\n"); 1218 } 1219 1220 static void add_srcversion(struct buffer *b, struct module *mod) 1221 { 1222 if (mod->srcversion[0]) { 1223 buf_printf(b, "\n"); 1224 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 1225 mod->srcversion); 1226 } 1227 } 1228 1229 static void write_if_changed(struct buffer *b, const char *fname) 1230 { 1231 char *tmp; 1232 FILE *file; 1233 struct stat st; 1234 1235 file = fopen(fname, "r"); 1236 if (!file) 1237 goto write; 1238 1239 if (fstat(fileno(file), &st) < 0) 1240 goto close_write; 1241 1242 if (st.st_size != b->pos) 1243 goto close_write; 1244 1245 tmp = NOFAIL(malloc(b->pos)); 1246 if (fread(tmp, 1, b->pos, file) != b->pos) 1247 goto free_write; 1248 1249 if (memcmp(tmp, b->p, b->pos) != 0) 1250 goto free_write; 1251 1252 free(tmp); 1253 fclose(file); 1254 return; 1255 1256 free_write: 1257 free(tmp); 1258 close_write: 1259 fclose(file); 1260 write: 1261 file = fopen(fname, "w"); 1262 if (!file) { 1263 perror(fname); 1264 exit(1); 1265 } 1266 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 1267 perror(fname); 1268 exit(1); 1269 } 1270 fclose(file); 1271 } 1272 1273 /* parse Module.symvers file. line format: 1274 * 0x12345678<tab>symbol<tab>module[<tab>export] 1275 **/ 1276 static void read_dump(const char *fname, unsigned int kernel) 1277 { 1278 unsigned long size, pos = 0; 1279 void *file = grab_file(fname, &size); 1280 char *line; 1281 1282 if (!file) 1283 /* No symbol versions, silently ignore */ 1284 return; 1285 1286 while ((line = get_next_line(&pos, file, size))) { 1287 char *symname, *modname, *d, *export; 1288 unsigned int crc; 1289 struct module *mod; 1290 struct symbol *s; 1291 1292 if (!(symname = strchr(line, '\t'))) 1293 goto fail; 1294 *symname++ = '\0'; 1295 if (!(modname = strchr(symname, '\t'))) 1296 goto fail; 1297 *modname++ = '\0'; 1298 if ((export = strchr(modname, '\t')) != NULL) 1299 *export++ = '\0'; 1300 1301 crc = strtoul(line, &d, 16); 1302 if (*symname == '\0' || *modname == '\0' || *d != '\0') 1303 goto fail; 1304 1305 if (!(mod = find_module(modname))) { 1306 if (is_vmlinux(modname)) { 1307 have_vmlinux = 1; 1308 } 1309 mod = new_module(NOFAIL(strdup(modname))); 1310 mod->skip = 1; 1311 } 1312 s = sym_add_exported(symname, mod, export_no(export)); 1313 s->kernel = kernel; 1314 s->preloaded = 1; 1315 sym_update_crc(symname, mod, crc, export_no(export)); 1316 } 1317 return; 1318 fail: 1319 fatal("parse error in symbol dump file\n"); 1320 } 1321 1322 /* For normal builds always dump all symbols. 1323 * For external modules only dump symbols 1324 * that are not read from kernel Module.symvers. 1325 **/ 1326 static int dump_sym(struct symbol *sym) 1327 { 1328 if (!external_module) 1329 return 1; 1330 if (sym->vmlinux || sym->kernel) 1331 return 0; 1332 return 1; 1333 } 1334 1335 static void write_dump(const char *fname) 1336 { 1337 struct buffer buf = { }; 1338 struct symbol *symbol; 1339 int n; 1340 1341 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 1342 symbol = symbolhash[n]; 1343 while (symbol) { 1344 if (dump_sym(symbol)) 1345 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", 1346 symbol->crc, symbol->name, 1347 symbol->module->name, 1348 export_str(symbol->export)); 1349 symbol = symbol->next; 1350 } 1351 } 1352 write_if_changed(&buf, fname); 1353 } 1354 1355 int main(int argc, char **argv) 1356 { 1357 struct module *mod; 1358 struct buffer buf = { }; 1359 char fname[SZ]; 1360 char *kernel_read = NULL, *module_read = NULL; 1361 char *dump_write = NULL; 1362 int opt; 1363 1364 while ((opt = getopt(argc, argv, "i:I:mo:a")) != -1) { 1365 switch(opt) { 1366 case 'i': 1367 kernel_read = optarg; 1368 break; 1369 case 'I': 1370 module_read = optarg; 1371 external_module = 1; 1372 break; 1373 case 'm': 1374 modversions = 1; 1375 break; 1376 case 'o': 1377 dump_write = optarg; 1378 break; 1379 case 'a': 1380 all_versions = 1; 1381 break; 1382 default: 1383 exit(1); 1384 } 1385 } 1386 1387 if (kernel_read) 1388 read_dump(kernel_read, 1); 1389 if (module_read) 1390 read_dump(module_read, 0); 1391 1392 while (optind < argc) { 1393 read_symbols(argv[optind++]); 1394 } 1395 1396 for (mod = modules; mod; mod = mod->next) { 1397 if (mod->skip) 1398 continue; 1399 check_license(mod); 1400 } 1401 1402 for (mod = modules; mod; mod = mod->next) { 1403 if (mod->skip) 1404 continue; 1405 1406 buf.pos = 0; 1407 1408 add_header(&buf, mod); 1409 add_versions(&buf, mod); 1410 add_depends(&buf, mod, modules); 1411 add_moddevtable(&buf, mod); 1412 add_srcversion(&buf, mod); 1413 1414 sprintf(fname, "%s.mod.c", mod->name); 1415 write_if_changed(&buf, fname); 1416 } 1417 1418 if (dump_write) 1419 write_dump(dump_write); 1420 1421 return 0; 1422 } 1423