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 { 28 export_plain, export_unused, export_gpl, 29 export_unused_gpl, export_gpl_future, export_unknown 30 }; 31 32 void fatal(const char *fmt, ...) 33 { 34 va_list arglist; 35 36 fprintf(stderr, "FATAL: "); 37 38 va_start(arglist, fmt); 39 vfprintf(stderr, fmt, arglist); 40 va_end(arglist); 41 42 exit(1); 43 } 44 45 void warn(const char *fmt, ...) 46 { 47 va_list arglist; 48 49 fprintf(stderr, "WARNING: "); 50 51 va_start(arglist, fmt); 52 vfprintf(stderr, fmt, arglist); 53 va_end(arglist); 54 } 55 56 static int is_vmlinux(const char *modname) 57 { 58 const char *myname; 59 60 if ((myname = strrchr(modname, '/'))) 61 myname++; 62 else 63 myname = modname; 64 65 return strcmp(myname, "vmlinux") == 0; 66 } 67 68 void *do_nofail(void *ptr, const char *expr) 69 { 70 if (!ptr) { 71 fatal("modpost: Memory allocation failure: %s.\n", expr); 72 } 73 return ptr; 74 } 75 76 /* A list of all modules we processed */ 77 78 static struct module *modules; 79 80 static struct module *find_module(char *modname) 81 { 82 struct module *mod; 83 84 for (mod = modules; mod; mod = mod->next) 85 if (strcmp(mod->name, modname) == 0) 86 break; 87 return mod; 88 } 89 90 static struct module *new_module(char *modname) 91 { 92 struct module *mod; 93 char *p, *s; 94 95 mod = NOFAIL(malloc(sizeof(*mod))); 96 memset(mod, 0, sizeof(*mod)); 97 p = NOFAIL(strdup(modname)); 98 99 /* strip trailing .o */ 100 if ((s = strrchr(p, '.')) != NULL) 101 if (strcmp(s, ".o") == 0) 102 *s = '\0'; 103 104 /* add to list */ 105 mod->name = p; 106 mod->gpl_compatible = -1; 107 mod->next = modules; 108 modules = mod; 109 110 return mod; 111 } 112 113 /* A hash of all exported symbols, 114 * struct symbol is also used for lists of unresolved symbols */ 115 116 #define SYMBOL_HASH_SIZE 1024 117 118 struct symbol { 119 struct symbol *next; 120 struct module *module; 121 unsigned int crc; 122 int crc_valid; 123 unsigned int weak:1; 124 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ 125 unsigned int kernel:1; /* 1 if symbol is from kernel 126 * (only for external modules) **/ 127 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */ 128 enum export export; /* Type of export */ 129 char name[0]; 130 }; 131 132 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 133 134 /* This is based on the hash agorithm from gdbm, via tdb */ 135 static inline unsigned int tdb_hash(const char *name) 136 { 137 unsigned value; /* Used to compute the hash value. */ 138 unsigned i; /* Used to cycle through random values. */ 139 140 /* Set the initial value from the key size. */ 141 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++) 142 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 143 144 return (1103515243 * value + 12345); 145 } 146 147 /** 148 * Allocate a new symbols for use in the hash of exported symbols or 149 * the list of unresolved symbols per module 150 **/ 151 static struct symbol *alloc_symbol(const char *name, unsigned int weak, 152 struct symbol *next) 153 { 154 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 155 156 memset(s, 0, sizeof(*s)); 157 strcpy(s->name, name); 158 s->weak = weak; 159 s->next = next; 160 return s; 161 } 162 163 /* For the hash of exported symbols */ 164 static struct symbol *new_symbol(const char *name, struct module *module, 165 enum export export) 166 { 167 unsigned int hash; 168 struct symbol *new; 169 170 hash = tdb_hash(name) % SYMBOL_HASH_SIZE; 171 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); 172 new->module = module; 173 new->export = export; 174 return new; 175 } 176 177 static struct symbol *find_symbol(const char *name) 178 { 179 struct symbol *s; 180 181 /* For our purposes, .foo matches foo. PPC64 needs this. */ 182 if (name[0] == '.') 183 name++; 184 185 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) { 186 if (strcmp(s->name, name) == 0) 187 return s; 188 } 189 return NULL; 190 } 191 192 static struct { 193 const char *str; 194 enum export export; 195 } export_list[] = { 196 { .str = "EXPORT_SYMBOL", .export = export_plain }, 197 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused }, 198 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl }, 199 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl }, 200 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future }, 201 { .str = "(unknown)", .export = export_unknown }, 202 }; 203 204 205 static const char *export_str(enum export ex) 206 { 207 return export_list[ex].str; 208 } 209 210 static enum export export_no(const char * s) 211 { 212 int i; 213 if (!s) 214 return export_unknown; 215 for (i = 0; export_list[i].export != export_unknown; i++) { 216 if (strcmp(export_list[i].str, s) == 0) 217 return export_list[i].export; 218 } 219 return export_unknown; 220 } 221 222 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec) 223 { 224 if (sec == elf->export_sec) 225 return export_plain; 226 else if (sec == elf->export_unused_sec) 227 return export_unused; 228 else if (sec == elf->export_gpl_sec) 229 return export_gpl; 230 else if (sec == elf->export_unused_gpl_sec) 231 return export_unused_gpl; 232 else if (sec == elf->export_gpl_future_sec) 233 return export_gpl_future; 234 else 235 return export_unknown; 236 } 237 238 /** 239 * Add an exported symbol - it may have already been added without a 240 * CRC, in this case just update the CRC 241 **/ 242 static struct symbol *sym_add_exported(const char *name, struct module *mod, 243 enum export export) 244 { 245 struct symbol *s = find_symbol(name); 246 247 if (!s) { 248 s = new_symbol(name, mod, export); 249 } else { 250 if (!s->preloaded) { 251 warn("%s: '%s' exported twice. Previous export " 252 "was in %s%s\n", mod->name, name, 253 s->module->name, 254 is_vmlinux(s->module->name) ?"":".ko"); 255 } 256 } 257 s->preloaded = 0; 258 s->vmlinux = is_vmlinux(mod->name); 259 s->kernel = 0; 260 s->export = export; 261 return s; 262 } 263 264 static void sym_update_crc(const char *name, struct module *mod, 265 unsigned int crc, enum export export) 266 { 267 struct symbol *s = find_symbol(name); 268 269 if (!s) 270 s = new_symbol(name, mod, export); 271 s->crc = crc; 272 s->crc_valid = 1; 273 } 274 275 void *grab_file(const char *filename, unsigned long *size) 276 { 277 struct stat st; 278 void *map; 279 int fd; 280 281 fd = open(filename, O_RDONLY); 282 if (fd < 0 || fstat(fd, &st) != 0) 283 return NULL; 284 285 *size = st.st_size; 286 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 287 close(fd); 288 289 if (map == MAP_FAILED) 290 return NULL; 291 return map; 292 } 293 294 /** 295 * Return a copy of the next line in a mmap'ed file. 296 * spaces in the beginning of the line is trimmed away. 297 * Return a pointer to a static buffer. 298 **/ 299 char* get_next_line(unsigned long *pos, void *file, unsigned long size) 300 { 301 static char line[4096]; 302 int skip = 1; 303 size_t len = 0; 304 signed char *p = (signed char *)file + *pos; 305 char *s = line; 306 307 for (; *pos < size ; (*pos)++) 308 { 309 if (skip && isspace(*p)) { 310 p++; 311 continue; 312 } 313 skip = 0; 314 if (*p != '\n' && (*pos < size)) { 315 len++; 316 *s++ = *p++; 317 if (len > 4095) 318 break; /* Too long, stop */ 319 } else { 320 /* End of string */ 321 *s = '\0'; 322 return line; 323 } 324 } 325 /* End of buffer */ 326 return NULL; 327 } 328 329 void release_file(void *file, unsigned long size) 330 { 331 munmap(file, size); 332 } 333 334 static void parse_elf(struct elf_info *info, const char *filename) 335 { 336 unsigned int i; 337 Elf_Ehdr *hdr = info->hdr; 338 Elf_Shdr *sechdrs; 339 Elf_Sym *sym; 340 341 hdr = grab_file(filename, &info->size); 342 if (!hdr) { 343 perror(filename); 344 exit(1); 345 } 346 info->hdr = hdr; 347 if (info->size < sizeof(*hdr)) 348 goto truncated; 349 350 /* Fix endianness in ELF header */ 351 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 352 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 353 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 354 hdr->e_machine = TO_NATIVE(hdr->e_machine); 355 sechdrs = (void *)hdr + hdr->e_shoff; 356 info->sechdrs = sechdrs; 357 358 /* Fix endianness in section headers */ 359 for (i = 0; i < hdr->e_shnum; i++) { 360 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 361 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 362 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 363 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 364 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 365 } 366 /* Find symbol table. */ 367 for (i = 1; i < hdr->e_shnum; i++) { 368 const char *secstrings 369 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 370 const char *secname; 371 372 if (sechdrs[i].sh_offset > info->size) 373 goto truncated; 374 secname = secstrings + sechdrs[i].sh_name; 375 if (strcmp(secname, ".modinfo") == 0) { 376 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 377 info->modinfo_len = sechdrs[i].sh_size; 378 } else if (strcmp(secname, "__ksymtab") == 0) 379 info->export_sec = i; 380 else if (strcmp(secname, "__ksymtab_unused") == 0) 381 info->export_unused_sec = i; 382 else if (strcmp(secname, "__ksymtab_gpl") == 0) 383 info->export_gpl_sec = i; 384 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0) 385 info->export_unused_gpl_sec = i; 386 else if (strcmp(secname, "__ksymtab_gpl_future") == 0) 387 info->export_gpl_future_sec = i; 388 389 if (sechdrs[i].sh_type != SHT_SYMTAB) 390 continue; 391 392 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; 393 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset 394 + sechdrs[i].sh_size; 395 info->strtab = (void *)hdr + 396 sechdrs[sechdrs[i].sh_link].sh_offset; 397 } 398 if (!info->symtab_start) { 399 fatal("%s has no symtab?\n", filename); 400 } 401 /* Fix endianness in symbols */ 402 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 403 sym->st_shndx = TO_NATIVE(sym->st_shndx); 404 sym->st_name = TO_NATIVE(sym->st_name); 405 sym->st_value = TO_NATIVE(sym->st_value); 406 sym->st_size = TO_NATIVE(sym->st_size); 407 } 408 return; 409 410 truncated: 411 fatal("%s is truncated.\n", filename); 412 } 413 414 static void parse_elf_finish(struct elf_info *info) 415 { 416 release_file(info->hdr, info->size); 417 } 418 419 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_" 420 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_" 421 422 static void handle_modversions(struct module *mod, struct elf_info *info, 423 Elf_Sym *sym, const char *symname) 424 { 425 unsigned int crc; 426 enum export export = export_from_sec(info, sym->st_shndx); 427 428 switch (sym->st_shndx) { 429 case SHN_COMMON: 430 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 431 break; 432 case SHN_ABS: 433 /* CRC'd symbol */ 434 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) { 435 crc = (unsigned int) sym->st_value; 436 sym_update_crc(symname + strlen(CRC_PFX), mod, crc, 437 export); 438 } 439 break; 440 case SHN_UNDEF: 441 /* undefined symbol */ 442 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 443 ELF_ST_BIND(sym->st_info) != STB_WEAK) 444 break; 445 /* ignore global offset table */ 446 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 447 break; 448 /* ignore __this_module, it will be resolved shortly */ 449 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0) 450 break; 451 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ 452 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) 453 /* add compatibility with older glibc */ 454 #ifndef STT_SPARC_REGISTER 455 #define STT_SPARC_REGISTER STT_REGISTER 456 #endif 457 if (info->hdr->e_machine == EM_SPARC || 458 info->hdr->e_machine == EM_SPARCV9) { 459 /* Ignore register directives. */ 460 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 461 break; 462 if (symname[0] == '.') { 463 char *munged = strdup(symname); 464 munged[0] = '_'; 465 munged[1] = toupper(munged[1]); 466 symname = munged; 467 } 468 } 469 #endif 470 471 if (memcmp(symname, MODULE_SYMBOL_PREFIX, 472 strlen(MODULE_SYMBOL_PREFIX)) == 0) 473 mod->unres = alloc_symbol(symname + 474 strlen(MODULE_SYMBOL_PREFIX), 475 ELF_ST_BIND(sym->st_info) == STB_WEAK, 476 mod->unres); 477 break; 478 default: 479 /* All exported symbols */ 480 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) { 481 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod, 482 export); 483 } 484 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0) 485 mod->has_init = 1; 486 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0) 487 mod->has_cleanup = 1; 488 break; 489 } 490 } 491 492 /** 493 * Parse tag=value strings from .modinfo section 494 **/ 495 static char *next_string(char *string, unsigned long *secsize) 496 { 497 /* Skip non-zero chars */ 498 while (string[0]) { 499 string++; 500 if ((*secsize)-- <= 1) 501 return NULL; 502 } 503 504 /* Skip any zero padding. */ 505 while (!string[0]) { 506 string++; 507 if ((*secsize)-- <= 1) 508 return NULL; 509 } 510 return string; 511 } 512 513 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len, 514 const char *tag, char *info) 515 { 516 char *p; 517 unsigned int taglen = strlen(tag); 518 unsigned long size = modinfo_len; 519 520 if (info) { 521 size -= info - (char *)modinfo; 522 modinfo = next_string(info, &size); 523 } 524 525 for (p = modinfo; p; p = next_string(p, &size)) { 526 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 527 return p + taglen + 1; 528 } 529 return NULL; 530 } 531 532 static char *get_modinfo(void *modinfo, unsigned long modinfo_len, 533 const char *tag) 534 535 { 536 return get_next_modinfo(modinfo, modinfo_len, tag, NULL); 537 } 538 539 /** 540 * Test if string s ends in string sub 541 * return 0 if match 542 **/ 543 static int strrcmp(const char *s, const char *sub) 544 { 545 int slen, sublen; 546 547 if (!s || !sub) 548 return 1; 549 550 slen = strlen(s); 551 sublen = strlen(sub); 552 553 if ((slen == 0) || (sublen == 0)) 554 return 1; 555 556 if (sublen > slen) 557 return 1; 558 559 return memcmp(s + slen - sublen, sub, sublen); 560 } 561 562 /** 563 * Whitelist to allow certain references to pass with no warning. 564 * Pattern 1: 565 * If a module parameter is declared __initdata and permissions=0 566 * then this is legal despite the warning generated. 567 * We cannot see value of permissions here, so just ignore 568 * this pattern. 569 * The pattern is identified by: 570 * tosec = .init.data 571 * fromsec = .data* 572 * atsym =__param* 573 * 574 * Pattern 2: 575 * Many drivers utilise a *driver container with references to 576 * add, remove, probe functions etc. 577 * These functions may often be marked __init and we do not want to 578 * warn here. 579 * the pattern is identified by: 580 * tosec = .init.text | .exit.text | .init.data 581 * fromsec = .data 582 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one 583 **/ 584 static int secref_whitelist(const char *tosec, const char *fromsec, 585 const char *atsym) 586 { 587 int f1 = 1, f2 = 1; 588 const char **s; 589 const char *pat2sym[] = { 590 "driver", 591 "_template", /* scsi uses *_template a lot */ 592 "_sht", /* scsi also used *_sht to some extent */ 593 "_ops", 594 "_probe", 595 "_probe_one", 596 NULL 597 }; 598 599 /* Check for pattern 1 */ 600 if (strcmp(tosec, ".init.data") != 0) 601 f1 = 0; 602 if (strncmp(fromsec, ".data", strlen(".data")) != 0) 603 f1 = 0; 604 if (strncmp(atsym, "__param", strlen("__param")) != 0) 605 f1 = 0; 606 607 if (f1) 608 return f1; 609 610 /* Check for pattern 2 */ 611 if ((strcmp(tosec, ".init.text") != 0) && 612 (strcmp(tosec, ".exit.text") != 0) && 613 (strcmp(tosec, ".init.data") != 0)) 614 f2 = 0; 615 if (strcmp(fromsec, ".data") != 0) 616 f2 = 0; 617 618 for (s = pat2sym; *s; s++) 619 if (strrcmp(atsym, *s) == 0) 620 f1 = 1; 621 622 return f1 && f2; 623 } 624 625 /** 626 * Find symbol based on relocation record info. 627 * In some cases the symbol supplied is a valid symbol so 628 * return refsym. If st_name != 0 we assume this is a valid symbol. 629 * In other cases the symbol needs to be looked up in the symbol table 630 * based on section and address. 631 * **/ 632 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr, 633 Elf_Sym *relsym) 634 { 635 Elf_Sym *sym; 636 637 if (relsym->st_name != 0) 638 return relsym; 639 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 640 if (sym->st_shndx != relsym->st_shndx) 641 continue; 642 if (sym->st_value == addr) 643 return sym; 644 } 645 return NULL; 646 } 647 648 /* 649 * Find symbols before or equal addr and after addr - in the section sec. 650 * If we find two symbols with equal offset prefer one with a valid name. 651 * The ELF format may have a better way to detect what type of symbol 652 * it is, but this works for now. 653 **/ 654 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr, 655 const char *sec, 656 Elf_Sym **before, Elf_Sym **after) 657 { 658 Elf_Sym *sym; 659 Elf_Ehdr *hdr = elf->hdr; 660 Elf_Addr beforediff = ~0; 661 Elf_Addr afterdiff = ~0; 662 const char *secstrings = (void *)hdr + 663 elf->sechdrs[hdr->e_shstrndx].sh_offset; 664 665 *before = NULL; 666 *after = NULL; 667 668 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 669 const char *symsec; 670 671 if (sym->st_shndx >= SHN_LORESERVE) 672 continue; 673 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name; 674 if (strcmp(symsec, sec) != 0) 675 continue; 676 if (sym->st_value <= addr) { 677 if ((addr - sym->st_value) < beforediff) { 678 beforediff = addr - sym->st_value; 679 *before = sym; 680 } 681 else if ((addr - sym->st_value) == beforediff) { 682 /* equal offset, valid name? */ 683 const char *name = elf->strtab + sym->st_name; 684 if (name && strlen(name)) 685 *before = sym; 686 } 687 } 688 else 689 { 690 if ((sym->st_value - addr) < afterdiff) { 691 afterdiff = sym->st_value - addr; 692 *after = sym; 693 } 694 else if ((sym->st_value - addr) == afterdiff) { 695 /* equal offset, valid name? */ 696 const char *name = elf->strtab + sym->st_name; 697 if (name && strlen(name)) 698 *after = sym; 699 } 700 } 701 } 702 } 703 704 /** 705 * Print a warning about a section mismatch. 706 * Try to find symbols near it so user can find it. 707 * Check whitelist before warning - it may be a false positive. 708 **/ 709 static void warn_sec_mismatch(const char *modname, const char *fromsec, 710 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r) 711 { 712 const char *refsymname = ""; 713 Elf_Sym *before, *after; 714 Elf_Sym *refsym; 715 Elf_Ehdr *hdr = elf->hdr; 716 Elf_Shdr *sechdrs = elf->sechdrs; 717 const char *secstrings = (void *)hdr + 718 sechdrs[hdr->e_shstrndx].sh_offset; 719 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name; 720 721 find_symbols_between(elf, r.r_offset, fromsec, &before, &after); 722 723 refsym = find_elf_symbol(elf, r.r_addend, sym); 724 if (refsym && strlen(elf->strtab + refsym->st_name)) 725 refsymname = elf->strtab + refsym->st_name; 726 727 /* check whitelist - we may ignore it */ 728 if (before && 729 secref_whitelist(secname, fromsec, elf->strtab + before->st_name)) 730 return; 731 732 if (before && after) { 733 warn("%s - Section mismatch: reference to %s:%s from %s " 734 "between '%s' (at offset 0x%llx) and '%s'\n", 735 modname, secname, refsymname, fromsec, 736 elf->strtab + before->st_name, 737 (long long)r.r_offset, 738 elf->strtab + after->st_name); 739 } else if (before) { 740 warn("%s - Section mismatch: reference to %s:%s from %s " 741 "after '%s' (at offset 0x%llx)\n", 742 modname, secname, refsymname, fromsec, 743 elf->strtab + before->st_name, 744 (long long)r.r_offset); 745 } else if (after) { 746 warn("%s - Section mismatch: reference to %s:%s from %s " 747 "before '%s' (at offset -0x%llx)\n", 748 modname, secname, refsymname, fromsec, 749 elf->strtab + after->st_name, 750 (long long)r.r_offset); 751 } else { 752 warn("%s - Section mismatch: reference to %s:%s from %s " 753 "(offset 0x%llx)\n", 754 modname, secname, fromsec, refsymname, 755 (long long)r.r_offset); 756 } 757 } 758 759 /** 760 * A module includes a number of sections that are discarded 761 * either when loaded or when used as built-in. 762 * For loaded modules all functions marked __init and all data 763 * marked __initdata will be discarded when the module has been intialized. 764 * Likewise for modules used built-in the sections marked __exit 765 * are discarded because __exit marked function are supposed to be called 766 * only when a moduel is unloaded which never happes for built-in modules. 767 * The check_sec_ref() function traverses all relocation records 768 * to find all references to a section that reference a section that will 769 * be discarded and warns about it. 770 **/ 771 static void check_sec_ref(struct module *mod, const char *modname, 772 struct elf_info *elf, 773 int section(const char*), 774 int section_ref_ok(const char *)) 775 { 776 int i; 777 Elf_Sym *sym; 778 Elf_Ehdr *hdr = elf->hdr; 779 Elf_Shdr *sechdrs = elf->sechdrs; 780 const char *secstrings = (void *)hdr + 781 sechdrs[hdr->e_shstrndx].sh_offset; 782 783 /* Walk through all sections */ 784 for (i = 0; i < hdr->e_shnum; i++) { 785 const char *name = secstrings + sechdrs[i].sh_name; 786 const char *secname; 787 Elf_Rela r; 788 unsigned int r_sym; 789 /* We want to process only relocation sections and not .init */ 790 if (sechdrs[i].sh_type == SHT_RELA) { 791 Elf_Rela *rela; 792 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset; 793 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size; 794 name += strlen(".rela"); 795 if (section_ref_ok(name)) 796 continue; 797 798 for (rela = start; rela < stop; rela++) { 799 r.r_offset = TO_NATIVE(rela->r_offset); 800 #if KERNEL_ELFCLASS == ELFCLASS64 801 if (hdr->e_machine == EM_MIPS) { 802 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 803 r_sym = TO_NATIVE(r_sym); 804 } else { 805 r.r_info = TO_NATIVE(rela->r_info); 806 r_sym = ELF_R_SYM(r.r_info); 807 } 808 #else 809 r.r_info = TO_NATIVE(rela->r_info); 810 r_sym = ELF_R_SYM(r.r_info); 811 #endif 812 r.r_addend = TO_NATIVE(rela->r_addend); 813 sym = elf->symtab_start + r_sym; 814 /* Skip special sections */ 815 if (sym->st_shndx >= SHN_LORESERVE) 816 continue; 817 818 secname = secstrings + 819 sechdrs[sym->st_shndx].sh_name; 820 if (section(secname)) 821 warn_sec_mismatch(modname, name, 822 elf, sym, r); 823 } 824 } else if (sechdrs[i].sh_type == SHT_REL) { 825 Elf_Rel *rel; 826 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset; 827 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size; 828 name += strlen(".rel"); 829 if (section_ref_ok(name)) 830 continue; 831 832 for (rel = start; rel < stop; rel++) { 833 r.r_offset = TO_NATIVE(rel->r_offset); 834 #if KERNEL_ELFCLASS == ELFCLASS64 835 if (hdr->e_machine == EM_MIPS) { 836 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 837 r_sym = TO_NATIVE(r_sym); 838 } else { 839 r.r_info = TO_NATIVE(rel->r_info); 840 r_sym = ELF_R_SYM(r.r_info); 841 } 842 #else 843 r.r_info = TO_NATIVE(rel->r_info); 844 r_sym = ELF_R_SYM(r.r_info); 845 #endif 846 r.r_addend = 0; 847 sym = elf->symtab_start + r_sym; 848 /* Skip special sections */ 849 if (sym->st_shndx >= SHN_LORESERVE) 850 continue; 851 852 secname = secstrings + 853 sechdrs[sym->st_shndx].sh_name; 854 if (section(secname)) 855 warn_sec_mismatch(modname, name, 856 elf, sym, r); 857 } 858 } 859 } 860 } 861 862 /** 863 * Functions used only during module init is marked __init and is stored in 864 * a .init.text section. Likewise data is marked __initdata and stored in 865 * a .init.data section. 866 * If this section is one of these sections return 1 867 * See include/linux/init.h for the details 868 **/ 869 static int init_section(const char *name) 870 { 871 if (strcmp(name, ".init") == 0) 872 return 1; 873 if (strncmp(name, ".init.", strlen(".init.")) == 0) 874 return 1; 875 return 0; 876 } 877 878 /** 879 * Identify sections from which references to a .init section is OK. 880 * 881 * Unfortunately references to read only data that referenced .init 882 * sections had to be excluded. Almost all of these are false 883 * positives, they are created by gcc. The downside of excluding rodata 884 * is that there really are some user references from rodata to 885 * init code, e.g. drivers/video/vgacon.c: 886 * 887 * const struct consw vga_con = { 888 * con_startup: vgacon_startup, 889 * 890 * where vgacon_startup is __init. If you want to wade through the false 891 * positives, take out the check for rodata. 892 **/ 893 static int init_section_ref_ok(const char *name) 894 { 895 const char **s; 896 /* Absolute section names */ 897 const char *namelist1[] = { 898 ".init", 899 ".opd", /* see comment [OPD] at exit_section_ref_ok() */ 900 ".toc1", /* used by ppc64 */ 901 ".stab", 902 ".rodata", 903 ".text.lock", 904 "__bug_table", /* used by powerpc for BUG() */ 905 ".pci_fixup_header", 906 ".pci_fixup_final", 907 ".pdr", 908 "__param", 909 "__ex_table", 910 ".fixup", 911 ".smp_locks", 912 ".plt", /* seen on ARCH=um build on x86_64. Harmless */ 913 NULL 914 }; 915 /* Start of section names */ 916 const char *namelist2[] = { 917 ".init.", 918 ".altinstructions", 919 ".eh_frame", 920 ".debug", 921 NULL 922 }; 923 /* part of section name */ 924 const char *namelist3 [] = { 925 ".unwind", /* sample: IA_64.unwind.init.text */ 926 NULL 927 }; 928 929 for (s = namelist1; *s; s++) 930 if (strcmp(*s, name) == 0) 931 return 1; 932 for (s = namelist2; *s; s++) 933 if (strncmp(*s, name, strlen(*s)) == 0) 934 return 1; 935 for (s = namelist3; *s; s++) 936 if (strstr(name, *s) != NULL) 937 return 1; 938 if (strrcmp(name, ".init") == 0) 939 return 1; 940 return 0; 941 } 942 943 /* 944 * Functions used only during module exit is marked __exit and is stored in 945 * a .exit.text section. Likewise data is marked __exitdata and stored in 946 * a .exit.data section. 947 * If this section is one of these sections return 1 948 * See include/linux/init.h for the details 949 **/ 950 static int exit_section(const char *name) 951 { 952 if (strcmp(name, ".exit.text") == 0) 953 return 1; 954 if (strcmp(name, ".exit.data") == 0) 955 return 1; 956 return 0; 957 958 } 959 960 /* 961 * Identify sections from which references to a .exit section is OK. 962 * 963 * [OPD] Keith Ownes <kaos@sgi.com> commented: 964 * For our future {in}sanity, add a comment that this is the ppc .opd 965 * section, not the ia64 .opd section. 966 * ia64 .opd should not point to discarded sections. 967 * [.rodata] like for .init.text we ignore .rodata references -same reason 968 **/ 969 static int exit_section_ref_ok(const char *name) 970 { 971 const char **s; 972 /* Absolute section names */ 973 const char *namelist1[] = { 974 ".exit.text", 975 ".exit.data", 976 ".init.text", 977 ".rodata", 978 ".opd", /* See comment [OPD] */ 979 ".toc1", /* used by ppc64 */ 980 ".altinstructions", 981 ".pdr", 982 "__bug_table", /* used by powerpc for BUG() */ 983 ".exitcall.exit", 984 ".eh_frame", 985 ".stab", 986 "__ex_table", 987 ".fixup", 988 ".smp_locks", 989 ".plt", /* seen on ARCH=um build on x86_64. Harmless */ 990 NULL 991 }; 992 /* Start of section names */ 993 const char *namelist2[] = { 994 ".debug", 995 NULL 996 }; 997 /* part of section name */ 998 const char *namelist3 [] = { 999 ".unwind", /* Sample: IA_64.unwind.exit.text */ 1000 NULL 1001 }; 1002 1003 for (s = namelist1; *s; s++) 1004 if (strcmp(*s, name) == 0) 1005 return 1; 1006 for (s = namelist2; *s; s++) 1007 if (strncmp(*s, name, strlen(*s)) == 0) 1008 return 1; 1009 for (s = namelist3; *s; s++) 1010 if (strstr(name, *s) != NULL) 1011 return 1; 1012 return 0; 1013 } 1014 1015 static void read_symbols(char *modname) 1016 { 1017 const char *symname; 1018 char *version; 1019 char *license; 1020 struct module *mod; 1021 struct elf_info info = { }; 1022 Elf_Sym *sym; 1023 1024 parse_elf(&info, modname); 1025 1026 mod = new_module(modname); 1027 1028 /* When there's no vmlinux, don't print warnings about 1029 * unresolved symbols (since there'll be too many ;) */ 1030 if (is_vmlinux(modname)) { 1031 have_vmlinux = 1; 1032 mod->skip = 1; 1033 } 1034 1035 license = get_modinfo(info.modinfo, info.modinfo_len, "license"); 1036 while (license) { 1037 if (license_is_gpl_compatible(license)) 1038 mod->gpl_compatible = 1; 1039 else { 1040 mod->gpl_compatible = 0; 1041 break; 1042 } 1043 license = get_next_modinfo(info.modinfo, info.modinfo_len, 1044 "license", license); 1045 } 1046 1047 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 1048 symname = info.strtab + sym->st_name; 1049 1050 handle_modversions(mod, &info, sym, symname); 1051 handle_moddevtable(mod, &info, sym, symname); 1052 } 1053 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok); 1054 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok); 1055 1056 version = get_modinfo(info.modinfo, info.modinfo_len, "version"); 1057 if (version) 1058 maybe_frob_rcs_version(modname, version, info.modinfo, 1059 version - (char *)info.hdr); 1060 if (version || (all_versions && !is_vmlinux(modname))) 1061 get_src_version(modname, mod->srcversion, 1062 sizeof(mod->srcversion)-1); 1063 1064 parse_elf_finish(&info); 1065 1066 /* Our trick to get versioning for struct_module - it's 1067 * never passed as an argument to an exported function, so 1068 * the automatic versioning doesn't pick it up, but it's really 1069 * important anyhow */ 1070 if (modversions) 1071 mod->unres = alloc_symbol("struct_module", 0, mod->unres); 1072 } 1073 1074 #define SZ 500 1075 1076 /* We first write the generated file into memory using the 1077 * following helper, then compare to the file on disk and 1078 * only update the later if anything changed */ 1079 1080 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 1081 const char *fmt, ...) 1082 { 1083 char tmp[SZ]; 1084 int len; 1085 va_list ap; 1086 1087 va_start(ap, fmt); 1088 len = vsnprintf(tmp, SZ, fmt, ap); 1089 buf_write(buf, tmp, len); 1090 va_end(ap); 1091 } 1092 1093 void buf_write(struct buffer *buf, const char *s, int len) 1094 { 1095 if (buf->size - buf->pos < len) { 1096 buf->size += len + SZ; 1097 buf->p = realloc(buf->p, buf->size); 1098 } 1099 strncpy(buf->p + buf->pos, s, len); 1100 buf->pos += len; 1101 } 1102 1103 static void check_for_gpl_usage(enum export exp, const char *m, const char *s) 1104 { 1105 const char *e = is_vmlinux(m) ?"":".ko"; 1106 1107 switch (exp) { 1108 case export_gpl: 1109 fatal("modpost: GPL-incompatible module %s%s " 1110 "uses GPL-only symbol '%s'\n", m, e, s); 1111 break; 1112 case export_unused_gpl: 1113 fatal("modpost: GPL-incompatible module %s%s " 1114 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s); 1115 break; 1116 case export_gpl_future: 1117 warn("modpost: GPL-incompatible module %s%s " 1118 "uses future GPL-only symbol '%s'\n", m, e, s); 1119 break; 1120 case export_plain: 1121 case export_unused: 1122 case export_unknown: 1123 /* ignore */ 1124 break; 1125 } 1126 } 1127 1128 static void check_for_unused(enum export exp, const char* m, const char* s) 1129 { 1130 const char *e = is_vmlinux(m) ?"":".ko"; 1131 1132 switch (exp) { 1133 case export_unused: 1134 case export_unused_gpl: 1135 warn("modpost: module %s%s " 1136 "uses symbol '%s' marked UNUSED\n", m, e, s); 1137 break; 1138 default: 1139 /* ignore */ 1140 break; 1141 } 1142 } 1143 1144 static void check_exports(struct module *mod) 1145 { 1146 struct symbol *s, *exp; 1147 1148 for (s = mod->unres; s; s = s->next) { 1149 const char *basename; 1150 exp = find_symbol(s->name); 1151 if (!exp || exp->module == mod) 1152 continue; 1153 basename = strrchr(mod->name, '/'); 1154 if (basename) 1155 basename++; 1156 else 1157 basename = mod->name; 1158 if (!mod->gpl_compatible) 1159 check_for_gpl_usage(exp->export, basename, exp->name); 1160 check_for_unused(exp->export, basename, exp->name); 1161 } 1162 } 1163 1164 /** 1165 * Header for the generated file 1166 **/ 1167 static void add_header(struct buffer *b, struct module *mod) 1168 { 1169 buf_printf(b, "#include <linux/module.h>\n"); 1170 buf_printf(b, "#include <linux/vermagic.h>\n"); 1171 buf_printf(b, "#include <linux/compiler.h>\n"); 1172 buf_printf(b, "\n"); 1173 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 1174 buf_printf(b, "\n"); 1175 buf_printf(b, "struct module __this_module\n"); 1176 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 1177 buf_printf(b, " .name = KBUILD_MODNAME,\n"); 1178 if (mod->has_init) 1179 buf_printf(b, " .init = init_module,\n"); 1180 if (mod->has_cleanup) 1181 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 1182 " .exit = cleanup_module,\n" 1183 "#endif\n"); 1184 buf_printf(b, "};\n"); 1185 } 1186 1187 /** 1188 * Record CRCs for unresolved symbols 1189 **/ 1190 static void add_versions(struct buffer *b, struct module *mod) 1191 { 1192 struct symbol *s, *exp; 1193 1194 for (s = mod->unres; s; s = s->next) { 1195 exp = find_symbol(s->name); 1196 if (!exp || exp->module == mod) { 1197 if (have_vmlinux && !s->weak) 1198 warn("\"%s\" [%s.ko] undefined!\n", 1199 s->name, mod->name); 1200 continue; 1201 } 1202 s->module = exp->module; 1203 s->crc_valid = exp->crc_valid; 1204 s->crc = exp->crc; 1205 } 1206 1207 if (!modversions) 1208 return; 1209 1210 buf_printf(b, "\n"); 1211 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 1212 buf_printf(b, "__attribute_used__\n"); 1213 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 1214 1215 for (s = mod->unres; s; s = s->next) { 1216 if (!s->module) { 1217 continue; 1218 } 1219 if (!s->crc_valid) { 1220 warn("\"%s\" [%s.ko] has no CRC!\n", 1221 s->name, mod->name); 1222 continue; 1223 } 1224 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); 1225 } 1226 1227 buf_printf(b, "};\n"); 1228 } 1229 1230 static void add_depends(struct buffer *b, struct module *mod, 1231 struct module *modules) 1232 { 1233 struct symbol *s; 1234 struct module *m; 1235 int first = 1; 1236 1237 for (m = modules; m; m = m->next) { 1238 m->seen = is_vmlinux(m->name); 1239 } 1240 1241 buf_printf(b, "\n"); 1242 buf_printf(b, "static const char __module_depends[]\n"); 1243 buf_printf(b, "__attribute_used__\n"); 1244 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 1245 buf_printf(b, "\"depends="); 1246 for (s = mod->unres; s; s = s->next) { 1247 if (!s->module) 1248 continue; 1249 1250 if (s->module->seen) 1251 continue; 1252 1253 s->module->seen = 1; 1254 buf_printf(b, "%s%s", first ? "" : ",", 1255 strrchr(s->module->name, '/') + 1); 1256 first = 0; 1257 } 1258 buf_printf(b, "\";\n"); 1259 } 1260 1261 static void add_srcversion(struct buffer *b, struct module *mod) 1262 { 1263 if (mod->srcversion[0]) { 1264 buf_printf(b, "\n"); 1265 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 1266 mod->srcversion); 1267 } 1268 } 1269 1270 static void write_if_changed(struct buffer *b, const char *fname) 1271 { 1272 char *tmp; 1273 FILE *file; 1274 struct stat st; 1275 1276 file = fopen(fname, "r"); 1277 if (!file) 1278 goto write; 1279 1280 if (fstat(fileno(file), &st) < 0) 1281 goto close_write; 1282 1283 if (st.st_size != b->pos) 1284 goto close_write; 1285 1286 tmp = NOFAIL(malloc(b->pos)); 1287 if (fread(tmp, 1, b->pos, file) != b->pos) 1288 goto free_write; 1289 1290 if (memcmp(tmp, b->p, b->pos) != 0) 1291 goto free_write; 1292 1293 free(tmp); 1294 fclose(file); 1295 return; 1296 1297 free_write: 1298 free(tmp); 1299 close_write: 1300 fclose(file); 1301 write: 1302 file = fopen(fname, "w"); 1303 if (!file) { 1304 perror(fname); 1305 exit(1); 1306 } 1307 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 1308 perror(fname); 1309 exit(1); 1310 } 1311 fclose(file); 1312 } 1313 1314 /* parse Module.symvers file. line format: 1315 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something] 1316 **/ 1317 static void read_dump(const char *fname, unsigned int kernel) 1318 { 1319 unsigned long size, pos = 0; 1320 void *file = grab_file(fname, &size); 1321 char *line; 1322 1323 if (!file) 1324 /* No symbol versions, silently ignore */ 1325 return; 1326 1327 while ((line = get_next_line(&pos, file, size))) { 1328 char *symname, *modname, *d, *export, *end; 1329 unsigned int crc; 1330 struct module *mod; 1331 struct symbol *s; 1332 1333 if (!(symname = strchr(line, '\t'))) 1334 goto fail; 1335 *symname++ = '\0'; 1336 if (!(modname = strchr(symname, '\t'))) 1337 goto fail; 1338 *modname++ = '\0'; 1339 if ((export = strchr(modname, '\t')) != NULL) 1340 *export++ = '\0'; 1341 if (export && ((end = strchr(export, '\t')) != NULL)) 1342 *end = '\0'; 1343 crc = strtoul(line, &d, 16); 1344 if (*symname == '\0' || *modname == '\0' || *d != '\0') 1345 goto fail; 1346 1347 if (!(mod = find_module(modname))) { 1348 if (is_vmlinux(modname)) { 1349 have_vmlinux = 1; 1350 } 1351 mod = new_module(NOFAIL(strdup(modname))); 1352 mod->skip = 1; 1353 } 1354 s = sym_add_exported(symname, mod, export_no(export)); 1355 s->kernel = kernel; 1356 s->preloaded = 1; 1357 sym_update_crc(symname, mod, crc, export_no(export)); 1358 } 1359 return; 1360 fail: 1361 fatal("parse error in symbol dump file\n"); 1362 } 1363 1364 /* For normal builds always dump all symbols. 1365 * For external modules only dump symbols 1366 * that are not read from kernel Module.symvers. 1367 **/ 1368 static int dump_sym(struct symbol *sym) 1369 { 1370 if (!external_module) 1371 return 1; 1372 if (sym->vmlinux || sym->kernel) 1373 return 0; 1374 return 1; 1375 } 1376 1377 static void write_dump(const char *fname) 1378 { 1379 struct buffer buf = { }; 1380 struct symbol *symbol; 1381 int n; 1382 1383 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 1384 symbol = symbolhash[n]; 1385 while (symbol) { 1386 if (dump_sym(symbol)) 1387 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", 1388 symbol->crc, symbol->name, 1389 symbol->module->name, 1390 export_str(symbol->export)); 1391 symbol = symbol->next; 1392 } 1393 } 1394 write_if_changed(&buf, fname); 1395 } 1396 1397 int main(int argc, char **argv) 1398 { 1399 struct module *mod; 1400 struct buffer buf = { }; 1401 char fname[SZ]; 1402 char *kernel_read = NULL, *module_read = NULL; 1403 char *dump_write = NULL; 1404 int opt; 1405 1406 while ((opt = getopt(argc, argv, "i:I:mo:a")) != -1) { 1407 switch(opt) { 1408 case 'i': 1409 kernel_read = optarg; 1410 break; 1411 case 'I': 1412 module_read = optarg; 1413 external_module = 1; 1414 break; 1415 case 'm': 1416 modversions = 1; 1417 break; 1418 case 'o': 1419 dump_write = optarg; 1420 break; 1421 case 'a': 1422 all_versions = 1; 1423 break; 1424 default: 1425 exit(1); 1426 } 1427 } 1428 1429 if (kernel_read) 1430 read_dump(kernel_read, 1); 1431 if (module_read) 1432 read_dump(module_read, 0); 1433 1434 while (optind < argc) { 1435 read_symbols(argv[optind++]); 1436 } 1437 1438 for (mod = modules; mod; mod = mod->next) { 1439 if (mod->skip) 1440 continue; 1441 check_exports(mod); 1442 } 1443 1444 for (mod = modules; mod; mod = mod->next) { 1445 if (mod->skip) 1446 continue; 1447 1448 buf.pos = 0; 1449 1450 add_header(&buf, mod); 1451 add_versions(&buf, mod); 1452 add_depends(&buf, mod, modules); 1453 add_moddevtable(&buf, mod); 1454 add_srcversion(&buf, mod); 1455 1456 sprintf(fname, "%s.mod.c", mod->name); 1457 write_if_changed(&buf, fname); 1458 } 1459 1460 if (dump_write) 1461 write_dump(dump_write); 1462 1463 return 0; 1464 } 1465