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