linux/scripts/mod/modpost.c
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   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? */
  19int modversions = 0;
  20/* Warn about undefined symbols? (do so if we have vmlinux) */
  21int have_vmlinux = 0;
  22/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  23static int all_versions = 0;
  24/* If we are modposting external module set to 1 */
  25static int external_module = 0;
  26/* Warn about section mismatch in vmlinux if set to 1 */
  27static int vmlinux_section_warnings = 1;
  28/* Only warn about unresolved symbols */
  29static int warn_unresolved = 0;
  30/* How a symbol is exported */
  31enum export {
  32        export_plain,      export_unused,     export_gpl,
  33        export_unused_gpl, export_gpl_future, export_unknown
  34};
  35
  36void fatal(const char *fmt, ...)
  37{
  38        va_list arglist;
  39
  40        fprintf(stderr, "FATAL: ");
  41
  42        va_start(arglist, fmt);
  43        vfprintf(stderr, fmt, arglist);
  44        va_end(arglist);
  45
  46        exit(1);
  47}
  48
  49void warn(const char *fmt, ...)
  50{
  51        va_list arglist;
  52
  53        fprintf(stderr, "WARNING: ");
  54
  55        va_start(arglist, fmt);
  56        vfprintf(stderr, fmt, arglist);
  57        va_end(arglist);
  58}
  59
  60void merror(const char *fmt, ...)
  61{
  62        va_list arglist;
  63
  64        fprintf(stderr, "ERROR: ");
  65
  66        va_start(arglist, fmt);
  67        vfprintf(stderr, fmt, arglist);
  68        va_end(arglist);
  69}
  70
  71static int is_vmlinux(const char *modname)
  72{
  73        const char *myname;
  74
  75        if ((myname = strrchr(modname, '/')))
  76                myname++;
  77        else
  78                myname = modname;
  79
  80        return (strcmp(myname, "vmlinux") == 0) ||
  81               (strcmp(myname, "vmlinux.o") == 0);
  82}
  83
  84void *do_nofail(void *ptr, const char *expr)
  85{
  86        if (!ptr) {
  87                fatal("modpost: Memory allocation failure: %s.\n", expr);
  88        }
  89        return ptr;
  90}
  91
  92/* A list of all modules we processed */
  93
  94static struct module *modules;
  95
  96static struct module *find_module(char *modname)
  97{
  98        struct module *mod;
  99
 100        for (mod = modules; mod; mod = mod->next)
 101                if (strcmp(mod->name, modname) == 0)
 102                        break;
 103        return mod;
 104}
 105
 106static struct module *new_module(char *modname)
 107{
 108        struct module *mod;
 109        char *p, *s;
 110
 111        mod = NOFAIL(malloc(sizeof(*mod)));
 112        memset(mod, 0, sizeof(*mod));
 113        p = NOFAIL(strdup(modname));
 114
 115        /* strip trailing .o */
 116        if ((s = strrchr(p, '.')) != NULL)
 117                if (strcmp(s, ".o") == 0)
 118                        *s = '\0';
 119
 120        /* add to list */
 121        mod->name = p;
 122        mod->gpl_compatible = -1;
 123        mod->next = modules;
 124        modules = mod;
 125
 126        return mod;
 127}
 128
 129/* A hash of all exported symbols,
 130 * struct symbol is also used for lists of unresolved symbols */
 131
 132#define SYMBOL_HASH_SIZE 1024
 133
 134struct symbol {
 135        struct symbol *next;
 136        struct module *module;
 137        unsigned int crc;
 138        int crc_valid;
 139        unsigned int weak:1;
 140        unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 141        unsigned int kernel:1;     /* 1 if symbol is from kernel
 142                                    *  (only for external modules) **/
 143        unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
 144        enum export  export;       /* Type of export */
 145        char name[0];
 146};
 147
 148static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 149
 150/* This is based on the hash agorithm from gdbm, via tdb */
 151static inline unsigned int tdb_hash(const char *name)
 152{
 153        unsigned value; /* Used to compute the hash value.  */
 154        unsigned   i;   /* Used to cycle through random values. */
 155
 156        /* Set the initial value from the key size. */
 157        for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
 158                value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 159
 160        return (1103515243 * value + 12345);
 161}
 162
 163/**
 164 * Allocate a new symbols for use in the hash of exported symbols or
 165 * the list of unresolved symbols per module
 166 **/
 167static struct symbol *alloc_symbol(const char *name, unsigned int weak,
 168                                   struct symbol *next)
 169{
 170        struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 171
 172        memset(s, 0, sizeof(*s));
 173        strcpy(s->name, name);
 174        s->weak = weak;
 175        s->next = next;
 176        return s;
 177}
 178
 179/* For the hash of exported symbols */
 180static struct symbol *new_symbol(const char *name, struct module *module,
 181                                 enum export export)
 182{
 183        unsigned int hash;
 184        struct symbol *new;
 185
 186        hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
 187        new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
 188        new->module = module;
 189        new->export = export;
 190        return new;
 191}
 192
 193static struct symbol *find_symbol(const char *name)
 194{
 195        struct symbol *s;
 196
 197        /* For our purposes, .foo matches foo.  PPC64 needs this. */
 198        if (name[0] == '.')
 199                name++;
 200
 201        for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
 202                if (strcmp(s->name, name) == 0)
 203                        return s;
 204        }
 205        return NULL;
 206}
 207
 208static struct {
 209        const char *str;
 210        enum export export;
 211} export_list[] = {
 212        { .str = "EXPORT_SYMBOL",            .export = export_plain },
 213        { .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 214        { .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 215        { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 216        { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 217        { .str = "(unknown)",                .export = export_unknown },
 218};
 219
 220
 221static const char *export_str(enum export ex)
 222{
 223        return export_list[ex].str;
 224}
 225
 226static enum export export_no(const char * s)
 227{
 228        int i;
 229        if (!s)
 230                return export_unknown;
 231        for (i = 0; export_list[i].export != export_unknown; i++) {
 232                if (strcmp(export_list[i].str, s) == 0)
 233                        return export_list[i].export;
 234        }
 235        return export_unknown;
 236}
 237
 238static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
 239{
 240        if (sec == elf->export_sec)
 241                return export_plain;
 242        else if (sec == elf->export_unused_sec)
 243                return export_unused;
 244        else if (sec == elf->export_gpl_sec)
 245                return export_gpl;
 246        else if (sec == elf->export_unused_gpl_sec)
 247                return export_unused_gpl;
 248        else if (sec == elf->export_gpl_future_sec)
 249                return export_gpl_future;
 250        else
 251                return export_unknown;
 252}
 253
 254/**
 255 * Add an exported symbol - it may have already been added without a
 256 * CRC, in this case just update the CRC
 257 **/
 258static struct symbol *sym_add_exported(const char *name, struct module *mod,
 259                                       enum export export)
 260{
 261        struct symbol *s = find_symbol(name);
 262
 263        if (!s) {
 264                s = new_symbol(name, mod, export);
 265        } else {
 266                if (!s->preloaded) {
 267                        warn("%s: '%s' exported twice. Previous export "
 268                             "was in %s%s\n", mod->name, name,
 269                             s->module->name,
 270                             is_vmlinux(s->module->name) ?"":".ko");
 271                } else {
 272                        /* In case Modules.symvers was out of date */
 273                        s->module = mod;
 274                }
 275        }
 276        s->preloaded = 0;
 277        s->vmlinux   = is_vmlinux(mod->name);
 278        s->kernel    = 0;
 279        s->export    = export;
 280        return s;
 281}
 282
 283static void sym_update_crc(const char *name, struct module *mod,
 284                           unsigned int crc, enum export export)
 285{
 286        struct symbol *s = find_symbol(name);
 287
 288        if (!s)
 289                s = new_symbol(name, mod, export);
 290        s->crc = crc;
 291        s->crc_valid = 1;
 292}
 293
 294void *grab_file(const char *filename, unsigned long *size)
 295{
 296        struct stat st;
 297        void *map;
 298        int fd;
 299
 300        fd = open(filename, O_RDONLY);
 301        if (fd < 0 || fstat(fd, &st) != 0)
 302                return NULL;
 303
 304        *size = st.st_size;
 305        map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 306        close(fd);
 307
 308        if (map == MAP_FAILED)
 309                return NULL;
 310        return map;
 311}
 312
 313/**
 314  * Return a copy of the next line in a mmap'ed file.
 315  * spaces in the beginning of the line is trimmed away.
 316  * Return a pointer to a static buffer.
 317  **/
 318char* get_next_line(unsigned long *pos, void *file, unsigned long size)
 319{
 320        static char line[4096];
 321        int skip = 1;
 322        size_t len = 0;
 323        signed char *p = (signed char *)file + *pos;
 324        char *s = line;
 325
 326        for (; *pos < size ; (*pos)++)
 327        {
 328                if (skip && isspace(*p)) {
 329                        p++;
 330                        continue;
 331                }
 332                skip = 0;
 333                if (*p != '\n' && (*pos < size)) {
 334                        len++;
 335                        *s++ = *p++;
 336                        if (len > 4095)
 337                                break; /* Too long, stop */
 338                } else {
 339                        /* End of string */
 340                        *s = '\0';
 341                        return line;
 342                }
 343        }
 344        /* End of buffer */
 345        return NULL;
 346}
 347
 348void release_file(void *file, unsigned long size)
 349{
 350        munmap(file, size);
 351}
 352
 353static int parse_elf(struct elf_info *info, const char *filename)
 354{
 355        unsigned int i;
 356        Elf_Ehdr *hdr;
 357        Elf_Shdr *sechdrs;
 358        Elf_Sym  *sym;
 359
 360        hdr = grab_file(filename, &info->size);
 361        if (!hdr) {
 362                perror(filename);
 363                exit(1);
 364        }
 365        info->hdr = hdr;
 366        if (info->size < sizeof(*hdr)) {
 367                /* file too small, assume this is an empty .o file */
 368                return 0;
 369        }
 370        /* Is this a valid ELF file? */
 371        if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 372            (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 373            (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 374            (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 375                /* Not an ELF file - silently ignore it */
 376                return 0;
 377        }
 378        /* Fix endianness in ELF header */
 379        hdr->e_shoff    = TO_NATIVE(hdr->e_shoff);
 380        hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
 381        hdr->e_shnum    = TO_NATIVE(hdr->e_shnum);
 382        hdr->e_machine  = TO_NATIVE(hdr->e_machine);
 383        hdr->e_type     = TO_NATIVE(hdr->e_type);
 384        sechdrs = (void *)hdr + hdr->e_shoff;
 385        info->sechdrs = sechdrs;
 386
 387        /* Check if file offset is correct */
 388        if (hdr->e_shoff > info->size) {
 389                fatal("section header offset=%u in file '%s' is bigger then filesize=%lu\n", hdr->e_shoff, filename, info->size);
 390                return 0;
 391        }
 392
 393        /* Fix endianness in section headers */
 394        for (i = 0; i < hdr->e_shnum; i++) {
 395                sechdrs[i].sh_type   = TO_NATIVE(sechdrs[i].sh_type);
 396                sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
 397                sechdrs[i].sh_size   = TO_NATIVE(sechdrs[i].sh_size);
 398                sechdrs[i].sh_link   = TO_NATIVE(sechdrs[i].sh_link);
 399                sechdrs[i].sh_name   = TO_NATIVE(sechdrs[i].sh_name);
 400                sechdrs[i].sh_info   = TO_NATIVE(sechdrs[i].sh_info);
 401                sechdrs[i].sh_addr   = TO_NATIVE(sechdrs[i].sh_addr);
 402        }
 403        /* Find symbol table. */
 404        for (i = 1; i < hdr->e_shnum; i++) {
 405                const char *secstrings
 406                        = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 407                const char *secname;
 408
 409                if (sechdrs[i].sh_offset > info->size) {
 410                        fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
 411                        return 0;
 412                }
 413                secname = secstrings + sechdrs[i].sh_name;
 414                if (strcmp(secname, ".modinfo") == 0) {
 415                        info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 416                        info->modinfo_len = sechdrs[i].sh_size;
 417                } else if (strcmp(secname, "__ksymtab") == 0)
 418                        info->export_sec = i;
 419                else if (strcmp(secname, "__ksymtab_unused") == 0)
 420                        info->export_unused_sec = i;
 421                else if (strcmp(secname, "__ksymtab_gpl") == 0)
 422                        info->export_gpl_sec = i;
 423                else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 424                        info->export_unused_gpl_sec = i;
 425                else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
 426                        info->export_gpl_future_sec = i;
 427
 428                if (sechdrs[i].sh_type != SHT_SYMTAB)
 429                        continue;
 430
 431                info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
 432                info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset
 433                                                 + sechdrs[i].sh_size;
 434                info->strtab       = (void *)hdr +
 435                                     sechdrs[sechdrs[i].sh_link].sh_offset;
 436        }
 437        if (!info->symtab_start) {
 438                fatal("%s has no symtab?\n", filename);
 439        }
 440        /* Fix endianness in symbols */
 441        for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 442                sym->st_shndx = TO_NATIVE(sym->st_shndx);
 443                sym->st_name  = TO_NATIVE(sym->st_name);
 444                sym->st_value = TO_NATIVE(sym->st_value);
 445                sym->st_size  = TO_NATIVE(sym->st_size);
 446        }
 447        return 1;
 448}
 449
 450static void parse_elf_finish(struct elf_info *info)
 451{
 452        release_file(info->hdr, info->size);
 453}
 454
 455#define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
 456#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
 457
 458static void handle_modversions(struct module *mod, struct elf_info *info,
 459                               Elf_Sym *sym, const char *symname)
 460{
 461        unsigned int crc;
 462        enum export export = export_from_sec(info, sym->st_shndx);
 463
 464        switch (sym->st_shndx) {
 465        case SHN_COMMON:
 466                warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 467                break;
 468        case SHN_ABS:
 469                /* CRC'd symbol */
 470                if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
 471                        crc = (unsigned int) sym->st_value;
 472                        sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
 473                                        export);
 474                }
 475                break;
 476        case SHN_UNDEF:
 477                /* undefined symbol */
 478                if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 479                    ELF_ST_BIND(sym->st_info) != STB_WEAK)
 480                        break;
 481                /* ignore global offset table */
 482                if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 483                        break;
 484                /* ignore __this_module, it will be resolved shortly */
 485                if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
 486                        break;
 487/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
 488#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
 489/* add compatibility with older glibc */
 490#ifndef STT_SPARC_REGISTER
 491#define STT_SPARC_REGISTER STT_REGISTER
 492#endif
 493                if (info->hdr->e_machine == EM_SPARC ||
 494                    info->hdr->e_machine == EM_SPARCV9) {
 495                        /* Ignore register directives. */
 496                        if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 497                                break;
 498                        if (symname[0] == '.') {
 499                                char *munged = strdup(symname);
 500                                munged[0] = '_';
 501                                munged[1] = toupper(munged[1]);
 502                                symname = munged;
 503                        }
 504                }
 505#endif
 506
 507                if (memcmp(symname, MODULE_SYMBOL_PREFIX,
 508                           strlen(MODULE_SYMBOL_PREFIX)) == 0)
 509                        mod->unres = alloc_symbol(symname +
 510                                                  strlen(MODULE_SYMBOL_PREFIX),
 511                                                  ELF_ST_BIND(sym->st_info) == STB_WEAK,
 512                                                  mod->unres);
 513                break;
 514        default:
 515                /* All exported symbols */
 516                if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
 517                        sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
 518                                        export);
 519                }
 520                if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
 521                        mod->has_init = 1;
 522                if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
 523                        mod->has_cleanup = 1;
 524                break;
 525        }
 526}
 527
 528/**
 529 * Parse tag=value strings from .modinfo section
 530 **/
 531static char *next_string(char *string, unsigned long *secsize)
 532{
 533        /* Skip non-zero chars */
 534        while (string[0]) {
 535                string++;
 536                if ((*secsize)-- <= 1)
 537                        return NULL;
 538        }
 539
 540        /* Skip any zero padding. */
 541        while (!string[0]) {
 542                string++;
 543                if ((*secsize)-- <= 1)
 544                        return NULL;
 545        }
 546        return string;
 547}
 548
 549static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
 550                              const char *tag, char *info)
 551{
 552        char *p;
 553        unsigned int taglen = strlen(tag);
 554        unsigned long size = modinfo_len;
 555
 556        if (info) {
 557                size -= info - (char *)modinfo;
 558                modinfo = next_string(info, &size);
 559        }
 560
 561        for (p = modinfo; p; p = next_string(p, &size)) {
 562                if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 563                        return p + taglen + 1;
 564        }
 565        return NULL;
 566}
 567
 568static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
 569                         const char *tag)
 570
 571{
 572        return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
 573}
 574
 575/**
 576 * Test if string s ends in string sub
 577 * return 0 if match
 578 **/
 579static int strrcmp(const char *s, const char *sub)
 580{
 581        int slen, sublen;
 582
 583        if (!s || !sub)
 584                return 1;
 585
 586        slen = strlen(s);
 587        sublen = strlen(sub);
 588
 589        if ((slen == 0) || (sublen == 0))
 590                return 1;
 591
 592        if (sublen > slen)
 593                return 1;
 594
 595        return memcmp(s + slen - sublen, sub, sublen);
 596}
 597
 598/*
 599 * Functions used only during module init is marked __init and is stored in
 600 * a .init.text section. Likewise data is marked __initdata and stored in
 601 * a .init.data section.
 602 * If this section is one of these sections return 1
 603 * See include/linux/init.h for the details
 604 */
 605static int init_section(const char *name)
 606{
 607        if (strcmp(name, ".init") == 0)
 608                return 1;
 609        if (strncmp(name, ".init.", strlen(".init.")) == 0)
 610                return 1;
 611        return 0;
 612}
 613
 614/*
 615 * Functions used only during module exit is marked __exit and is stored in
 616 * a .exit.text section. Likewise data is marked __exitdata and stored in
 617 * a .exit.data section.
 618 * If this section is one of these sections return 1
 619 * See include/linux/init.h for the details
 620 **/
 621static int exit_section(const char *name)
 622{
 623        if (strcmp(name, ".exit.text") == 0)
 624                return 1;
 625        if (strcmp(name, ".exit.data") == 0)
 626                return 1;
 627        return 0;
 628
 629}
 630
 631/*
 632 * Data sections are named like this:
 633 * .data | .data.rel | .data.rel.*
 634 * Return 1 if the specified section is a data section
 635 */
 636static int data_section(const char *name)
 637{
 638        if ((strcmp(name, ".data") == 0) ||
 639            (strcmp(name, ".data.rel") == 0) ||
 640            (strncmp(name, ".data.rel.", strlen(".data.rel.")) == 0))
 641                return 1;
 642        else
 643                return 0;
 644}
 645
 646/**
 647 * Whitelist to allow certain references to pass with no warning.
 648 *
 649 * Pattern 0:
 650 *   Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
 651 *   The pattern is identified by:
 652 *   fromsec = .text.init.refok* | .data.init.refok*
 653 *
 654 * Pattern 1:
 655 *   If a module parameter is declared __initdata and permissions=0
 656 *   then this is legal despite the warning generated.
 657 *   We cannot see value of permissions here, so just ignore
 658 *   this pattern.
 659 *   The pattern is identified by:
 660 *   tosec   = .init.data
 661 *   fromsec = .data*
 662 *   atsym   =__param*
 663 *
 664 * Pattern 2:
 665 *   Many drivers utilise a *driver container with references to
 666 *   add, remove, probe functions etc.
 667 *   These functions may often be marked __init and we do not want to
 668 *   warn here.
 669 *   the pattern is identified by:
 670 *   tosec   = init or exit section
 671 *   fromsec = data section
 672 *   atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console, *_timer
 673 *
 674 * Pattern 3:
 675 *   Whitelist all refereces from .text.head to .init.data
 676 *   Whitelist all refereces from .text.head to .init.text
 677 *
 678 * Pattern 4:
 679 *   Some symbols belong to init section but still it is ok to reference
 680 *   these from non-init sections as these symbols don't have any memory
 681 *   allocated for them and symbol address and value are same. So even
 682 *   if init section is freed, its ok to reference those symbols.
 683 *   For ex. symbols marking the init section boundaries.
 684 *   This pattern is identified by
 685 *   refsymname = __init_begin, _sinittext, _einittext
 686 *
 687 * Pattern 5:
 688 *   Xtensa uses literal sections for constants that are accessed PC-relative.
 689 *   Literal sections may safely reference their text sections.
 690 *   (Note that the name for the literal section omits any trailing '.text')
 691 *   tosec = <section>[.text]
 692 *   fromsec = <section>.literal
 693 **/
 694static int secref_whitelist(const char *modname, const char *tosec,
 695                            const char *fromsec, const char *atsym,
 696                            const char *refsymname)
 697{
 698        int len;
 699        const char **s;
 700        const char *pat2sym[] = {
 701                "driver",
 702                "_template", /* scsi uses *_template a lot */
 703                "_timer",    /* arm uses ops structures named _timer a lot */
 704                "_sht",      /* scsi also used *_sht to some extent */
 705                "_ops",
 706                "_probe",
 707                "_probe_one",
 708                "_console",
 709                NULL
 710        };
 711
 712        const char *pat3refsym[] = {
 713                "__init_begin",
 714                "_sinittext",
 715                "_einittext",
 716                NULL
 717        };
 718
 719        /* Check for pattern 0 */
 720        if ((strncmp(fromsec, ".text.init.refok", strlen(".text.init.refok")) == 0) ||
 721            (strncmp(fromsec, ".exit.text.refok", strlen(".exit.text.refok")) == 0) ||
 722            (strncmp(fromsec, ".data.init.refok", strlen(".data.init.refok")) == 0))
 723                return 1;
 724
 725        /* Check for pattern 1 */
 726        if ((strcmp(tosec, ".init.data") == 0) &&
 727            (strncmp(fromsec, ".data", strlen(".data")) == 0) &&
 728            (strncmp(atsym, "__param", strlen("__param")) == 0))
 729                return 1;
 730
 731        /* Check for pattern 2 */
 732        if ((init_section(tosec) || exit_section(tosec)) && data_section(fromsec))
 733                for (s = pat2sym; *s; s++)
 734                        if (strrcmp(atsym, *s) == 0)
 735                                return 1;
 736
 737        /* Check for pattern 3 */
 738        if ((strcmp(fromsec, ".text.head") == 0) &&
 739                ((strcmp(tosec, ".init.data") == 0) ||
 740                (strcmp(tosec, ".init.text") == 0)))
 741        return 1;
 742
 743        /* Check for pattern 4 */
 744        for (s = pat3refsym; *s; s++)
 745                if (strcmp(refsymname, *s) == 0)
 746                        return 1;
 747
 748        /* Check for pattern 5 */
 749        if (strrcmp(tosec, ".text") == 0)
 750                len = strlen(tosec) - strlen(".text");
 751        else
 752                len = strlen(tosec);
 753        if ((strncmp(tosec, fromsec, len) == 0) && (strlen(fromsec) > len) &&
 754            (strcmp(fromsec + len, ".literal") == 0))
 755                return 1;
 756
 757        return 0;
 758}
 759
 760/**
 761 * Find symbol based on relocation record info.
 762 * In some cases the symbol supplied is a valid symbol so
 763 * return refsym. If st_name != 0 we assume this is a valid symbol.
 764 * In other cases the symbol needs to be looked up in the symbol table
 765 * based on section and address.
 766 *  **/
 767static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
 768                                Elf_Sym *relsym)
 769{
 770        Elf_Sym *sym;
 771
 772        if (relsym->st_name != 0)
 773                return relsym;
 774        for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
 775                if (sym->st_shndx != relsym->st_shndx)
 776                        continue;
 777                if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
 778                        continue;
 779                if (sym->st_value == addr)
 780                        return sym;
 781        }
 782        return NULL;
 783}
 784
 785static inline int is_arm_mapping_symbol(const char *str)
 786{
 787        return str[0] == '$' && strchr("atd", str[1])
 788               && (str[2] == '\0' || str[2] == '.');
 789}
 790
 791/*
 792 * If there's no name there, ignore it; likewise, ignore it if it's
 793 * one of the magic symbols emitted used by current ARM tools.
 794 *
 795 * Otherwise if find_symbols_between() returns those symbols, they'll
 796 * fail the whitelist tests and cause lots of false alarms ... fixable
 797 * only by merging __exit and __init sections into __text, bloating
 798 * the kernel (which is especially evil on embedded platforms).
 799 */
 800static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
 801{
 802        const char *name = elf->strtab + sym->st_name;
 803
 804        if (!name || !strlen(name))
 805                return 0;
 806        return !is_arm_mapping_symbol(name);
 807}
 808
 809/*
 810 * Find symbols before or equal addr and after addr - in the section sec.
 811 * If we find two symbols with equal offset prefer one with a valid name.
 812 * The ELF format may have a better way to detect what type of symbol
 813 * it is, but this works for now.
 814 **/
 815static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
 816                                 const char *sec,
 817                                 Elf_Sym **before, Elf_Sym **after)
 818{
 819        Elf_Sym *sym;
 820        Elf_Ehdr *hdr = elf->hdr;
 821        Elf_Addr beforediff = ~0;
 822        Elf_Addr afterdiff = ~0;
 823        const char *secstrings = (void *)hdr +
 824                                 elf->sechdrs[hdr->e_shstrndx].sh_offset;
 825
 826        *before = NULL;
 827        *after = NULL;
 828
 829        for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
 830                const char *symsec;
 831
 832                if (sym->st_shndx >= SHN_LORESERVE)
 833                        continue;
 834                symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
 835                if (strcmp(symsec, sec) != 0)
 836                        continue;
 837                if (!is_valid_name(elf, sym))
 838                        continue;
 839                if (sym->st_value <= addr) {
 840                        if ((addr - sym->st_value) < beforediff) {
 841                                beforediff = addr - sym->st_value;
 842                                *before = sym;
 843                        }
 844                        else if ((addr - sym->st_value) == beforediff) {
 845                                *before = sym;
 846                        }
 847                }
 848                else
 849                {
 850                        if ((sym->st_value - addr) < afterdiff) {
 851                                afterdiff = sym->st_value - addr;
 852                                *after = sym;
 853                        }
 854                        else if ((sym->st_value - addr) == afterdiff) {
 855                                *after = sym;
 856                        }
 857                }
 858        }
 859}
 860
 861/**
 862 * Print a warning about a section mismatch.
 863 * Try to find symbols near it so user can find it.
 864 * Check whitelist before warning - it may be a false positive.
 865 **/
 866static void warn_sec_mismatch(const char *modname, const char *fromsec,
 867                              struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
 868{
 869        const char *refsymname = "";
 870        Elf_Sym *before, *after;
 871        Elf_Sym *refsym;
 872        Elf_Ehdr *hdr = elf->hdr;
 873        Elf_Shdr *sechdrs = elf->sechdrs;
 874        const char *secstrings = (void *)hdr +
 875                                 sechdrs[hdr->e_shstrndx].sh_offset;
 876        const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
 877
 878        find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
 879
 880        refsym = find_elf_symbol(elf, r.r_addend, sym);
 881        if (refsym && strlen(elf->strtab + refsym->st_name))
 882                refsymname = elf->strtab + refsym->st_name;
 883
 884        /* check whitelist - we may ignore it */
 885        if (secref_whitelist(modname, secname, fromsec,
 886                             before ? elf->strtab + before->st_name : "",
 887                             refsymname))
 888                return;
 889
 890        if (before && after) {
 891                warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
 892                     "(between '%s' and '%s')\n",
 893                     modname, fromsec, (unsigned long long)r.r_offset,
 894                     secname, refsymname,
 895                     elf->strtab + before->st_name,
 896                     elf->strtab + after->st_name);
 897        } else if (before) {
 898                warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
 899                     "(after '%s')\n",
 900                     modname, fromsec, (unsigned long long)r.r_offset,
 901                     secname, refsymname,
 902                     elf->strtab + before->st_name);
 903        } else if (after) {
 904                warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
 905                     "before '%s' (at offset -0x%llx)\n",
 906                     modname, fromsec, (unsigned long long)r.r_offset,
 907                     secname, refsymname,
 908                     elf->strtab + after->st_name);
 909        } else {
 910                warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
 911                     modname, fromsec, (unsigned long long)r.r_offset,
 912                     secname, refsymname);
 913        }
 914}
 915
 916static unsigned int *reloc_location(struct elf_info *elf,
 917                                           int rsection, Elf_Rela *r)
 918{
 919        Elf_Shdr *sechdrs = elf->sechdrs;
 920        int section = sechdrs[rsection].sh_info;
 921
 922        return (void *)elf->hdr + sechdrs[section].sh_offset +
 923                (r->r_offset - sechdrs[section].sh_addr);
 924}
 925
 926static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 927{
 928        unsigned int r_typ = ELF_R_TYPE(r->r_info);
 929        unsigned int *location = reloc_location(elf, rsection, r);
 930
 931        switch (r_typ) {
 932        case R_386_32:
 933                r->r_addend = TO_NATIVE(*location);
 934                break;
 935        case R_386_PC32:
 936                r->r_addend = TO_NATIVE(*location) + 4;
 937                /* For CONFIG_RELOCATABLE=y */
 938                if (elf->hdr->e_type == ET_EXEC)
 939                        r->r_addend += r->r_offset;
 940                break;
 941        }
 942        return 0;
 943}
 944
 945static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 946{
 947        unsigned int r_typ = ELF_R_TYPE(r->r_info);
 948
 949        switch (r_typ) {
 950        case R_ARM_ABS32:
 951                /* From ARM ABI: (S + A) | T */
 952                r->r_addend = (int)(long)(elf->symtab_start + ELF_R_SYM(r->r_info));
 953                break;
 954        case R_ARM_PC24:
 955                /* From ARM ABI: ((S + A) | T) - P */
 956                r->r_addend = (int)(long)(elf->hdr + elf->sechdrs[rsection].sh_offset +
 957                                          (r->r_offset - elf->sechdrs[rsection].sh_addr));
 958                break;
 959        default:
 960                return 1;
 961        }
 962        return 0;
 963}
 964
 965static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
 966{
 967        unsigned int r_typ = ELF_R_TYPE(r->r_info);
 968        unsigned int *location = reloc_location(elf, rsection, r);
 969        unsigned int inst;
 970
 971        if (r_typ == R_MIPS_HI16)
 972                return 1;       /* skip this */
 973        inst = TO_NATIVE(*location);
 974        switch (r_typ) {
 975        case R_MIPS_LO16:
 976                r->r_addend = inst & 0xffff;
 977                break;
 978        case R_MIPS_26:
 979                r->r_addend = (inst & 0x03ffffff) << 2;
 980                break;
 981        case R_MIPS_32:
 982                r->r_addend = inst;
 983                break;
 984        }
 985        return 0;
 986}
 987
 988/**
 989 * A module includes a number of sections that are discarded
 990 * either when loaded or when used as built-in.
 991 * For loaded modules all functions marked __init and all data
 992 * marked __initdata will be discarded when the module has been intialized.
 993 * Likewise for modules used built-in the sections marked __exit
 994 * are discarded because __exit marked function are supposed to be called
 995 * only when a moduel is unloaded which never happes for built-in modules.
 996 * The check_sec_ref() function traverses all relocation records
 997 * to find all references to a section that reference a section that will
 998 * be discarded and warns about it.
 999 **/
1000static void check_sec_ref(struct module *mod, const char *modname,
1001                          struct elf_info *elf,
1002                          int section(const char*),
1003                          int section_ref_ok(const char *))
1004{
1005        int i;
1006        Elf_Sym  *sym;
1007        Elf_Ehdr *hdr = elf->hdr;
1008        Elf_Shdr *sechdrs = elf->sechdrs;
1009        const char *secstrings = (void *)hdr +
1010                                 sechdrs[hdr->e_shstrndx].sh_offset;
1011
1012        /* Walk through all sections */
1013        for (i = 0; i < hdr->e_shnum; i++) {
1014                const char *name = secstrings + sechdrs[i].sh_name;
1015                const char *secname;
1016                Elf_Rela r;
1017                unsigned int r_sym;
1018                /* We want to process only relocation sections and not .init */
1019                if (sechdrs[i].sh_type == SHT_RELA) {
1020                        Elf_Rela *rela;
1021                        Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
1022                        Elf_Rela *stop  = (void*)start + sechdrs[i].sh_size;
1023                        name += strlen(".rela");
1024                        if (section_ref_ok(name))
1025                                continue;
1026
1027                        for (rela = start; rela < stop; rela++) {
1028                                r.r_offset = TO_NATIVE(rela->r_offset);
1029#if KERNEL_ELFCLASS == ELFCLASS64
1030                                if (hdr->e_machine == EM_MIPS) {
1031                                        unsigned int r_typ;
1032                                        r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1033                                        r_sym = TO_NATIVE(r_sym);
1034                                        r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1035                                        r.r_info = ELF64_R_INFO(r_sym, r_typ);
1036                                } else {
1037                                        r.r_info = TO_NATIVE(rela->r_info);
1038                                        r_sym = ELF_R_SYM(r.r_info);
1039                                }
1040#else
1041                                r.r_info = TO_NATIVE(rela->r_info);
1042                                r_sym = ELF_R_SYM(r.r_info);
1043#endif
1044                                r.r_addend = TO_NATIVE(rela->r_addend);
1045                                sym = elf->symtab_start + r_sym;
1046                                /* Skip special sections */
1047                                if (sym->st_shndx >= SHN_LORESERVE)
1048                                        continue;
1049
1050                                secname = secstrings +
1051                                        sechdrs[sym->st_shndx].sh_name;
1052                                if (section(secname))
1053                                        warn_sec_mismatch(modname, name,
1054                                                          elf, sym, r);
1055                        }
1056                } else if (sechdrs[i].sh_type == SHT_REL) {
1057                        Elf_Rel *rel;
1058                        Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
1059                        Elf_Rel *stop  = (void*)start + sechdrs[i].sh_size;
1060                        name += strlen(".rel");
1061                        if (section_ref_ok(name))
1062                                continue;
1063
1064                        for (rel = start; rel < stop; rel++) {
1065                                r.r_offset = TO_NATIVE(rel->r_offset);
1066#if KERNEL_ELFCLASS == ELFCLASS64
1067                                if (hdr->e_machine == EM_MIPS) {
1068                                        unsigned int r_typ;
1069                                        r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1070                                        r_sym = TO_NATIVE(r_sym);
1071                                        r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1072                                        r.r_info = ELF64_R_INFO(r_sym, r_typ);
1073                                } else {
1074                                        r.r_info = TO_NATIVE(rel->r_info);
1075                                        r_sym = ELF_R_SYM(r.r_info);
1076                                }
1077#else
1078                                r.r_info = TO_NATIVE(rel->r_info);
1079                                r_sym = ELF_R_SYM(r.r_info);
1080#endif
1081                                r.r_addend = 0;
1082                                switch (hdr->e_machine) {
1083                                case EM_386:
1084                                        if (addend_386_rel(elf, i, &r))
1085                                                continue;
1086                                        break;
1087                                case EM_ARM:
1088                                        if(addend_arm_rel(elf, i, &r))
1089                                                continue;
1090                                        break;
1091                                case EM_MIPS:
1092                                        if (addend_mips_rel(elf, i, &r))
1093                                                continue;
1094                                        break;
1095                                }
1096                                sym = elf->symtab_start + r_sym;
1097                                /* Skip special sections */
1098                                if (sym->st_shndx >= SHN_LORESERVE)
1099                                        continue;
1100
1101                                secname = secstrings +
1102                                        sechdrs[sym->st_shndx].sh_name;
1103                                if (section(secname))
1104                                        warn_sec_mismatch(modname, name,
1105                                                          elf, sym, r);
1106                        }
1107                }
1108        }
1109}
1110
1111/*
1112 * Identify sections from which references to either a
1113 * .init or a .exit section is OK.
1114 *
1115 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1116 * For our future {in}sanity, add a comment that this is the ppc .opd
1117 * section, not the ia64 .opd section.
1118 * ia64 .opd should not point to discarded sections.
1119 * [.rodata] like for .init.text we ignore .rodata references -same reason
1120 */
1121static int initexit_section_ref_ok(const char *name)
1122{
1123        const char **s;
1124        /* Absolute section names */
1125        const char *namelist1[] = {
1126                "__bug_table",          /* used by powerpc for BUG() */
1127                "__ex_table",
1128                ".altinstructions",
1129                ".cranges",             /* used by sh64 */
1130                ".fixup",
1131                ".machvec",             /* ia64 + powerpc uses these */
1132                ".machine.desc",
1133                ".opd",                 /* See comment [OPD] */
1134                "__dbe_table",
1135                ".parainstructions",
1136                ".pdr",
1137                ".plt",                 /* seen on ARCH=um build on x86_64. Harmless */
1138                ".smp_locks",
1139                ".stab",
1140                ".m68k_fixup",
1141                ".xt.prop",             /* xtensa informational section */
1142                ".xt.lit",              /* xtensa informational section */
1143                NULL
1144        };
1145        /* Start of section names */
1146        const char *namelist2[] = {
1147                ".debug",
1148                ".eh_frame",
1149                ".note",                /* ignore ELF notes - may contain anything */
1150                ".got",                 /* powerpc - global offset table */
1151                ".toc",                 /* powerpc - table of contents */
1152                NULL
1153        };
1154        /* part of section name */
1155        const char *namelist3 [] = {
1156                ".unwind",  /* Sample: IA_64.unwind.exit.text */
1157                NULL
1158        };
1159
1160        for (s = namelist1; *s; s++)
1161                if (strcmp(*s, name) == 0)
1162                        return 1;
1163        for (s = namelist2; *s; s++)
1164                if (strncmp(*s, name, strlen(*s)) == 0)
1165                        return 1;
1166        for (s = namelist3; *s; s++)
1167                if (strstr(name, *s) != NULL)
1168                        return 1;
1169        return 0;
1170}
1171
1172
1173/*
1174 * Identify sections from which references to a .init section is OK.
1175 *
1176 * Unfortunately references to read only data that referenced .init
1177 * sections had to be excluded. Almost all of these are false
1178 * positives, they are created by gcc. The downside of excluding rodata
1179 * is that there really are some user references from rodata to
1180 * init code, e.g. drivers/video/vgacon.c:
1181 *
1182 * const struct consw vga_con = {
1183 *        con_startup:            vgacon_startup,
1184 *
1185 * where vgacon_startup is __init.  If you want to wade through the false
1186 * positives, take out the check for rodata.
1187 */
1188static int init_section_ref_ok(const char *name)
1189{
1190        const char **s;
1191        /* Absolute section names */
1192        const char *namelist1[] = {
1193                "__dbe_table",          /* MIPS generate these */
1194                "__ftr_fixup",          /* powerpc cpu feature fixup */
1195                "__fw_ftr_fixup",       /* powerpc firmware feature fixup */
1196                "__param",
1197                ".data.rel.ro",         /* used by parisc64 */
1198                ".init",
1199                ".text.lock",
1200                NULL
1201        };
1202        /* Start of section names */
1203        const char *namelist2[] = {
1204                ".init.",
1205                ".pci_fixup",
1206                ".rodata",
1207                NULL
1208        };
1209
1210        if (initexit_section_ref_ok(name))
1211                return 1;
1212
1213        for (s = namelist1; *s; s++)
1214                if (strcmp(*s, name) == 0)
1215                        return 1;
1216        for (s = namelist2; *s; s++)
1217                if (strncmp(*s, name, strlen(*s)) == 0)
1218                        return 1;
1219
1220        /* If section name ends with ".init" we allow references
1221         * as is the case with .initcallN.init, .early_param.init, .taglist.init etc
1222         */
1223        if (strrcmp(name, ".init") == 0)
1224                return 1;
1225        return 0;
1226}
1227
1228/*
1229 * Identify sections from which references to a .exit section is OK.
1230 */
1231static int exit_section_ref_ok(const char *name)
1232{
1233        const char **s;
1234        /* Absolute section names */
1235        const char *namelist1[] = {
1236                ".exit.data",
1237                ".exit.text",
1238                ".exitcall.exit",
1239                ".rodata",
1240                NULL
1241        };
1242
1243        if (initexit_section_ref_ok(name))
1244                return 1;
1245
1246        for (s = namelist1; *s; s++)
1247                if (strcmp(*s, name) == 0)
1248                        return 1;
1249        return 0;
1250}
1251
1252static void read_symbols(char *modname)
1253{
1254        const char *symname;
1255        char *version;
1256        char *license;
1257        struct module *mod;
1258        struct elf_info info = { };
1259        Elf_Sym *sym;
1260
1261        if (!parse_elf(&info, modname))
1262                return;
1263
1264        mod = new_module(modname);
1265
1266        /* When there's no vmlinux, don't print warnings about
1267         * unresolved symbols (since there'll be too many ;) */
1268        if (is_vmlinux(modname)) {
1269                have_vmlinux = 1;
1270                mod->skip = 1;
1271        }
1272
1273        license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1274        while (license) {
1275                if (license_is_gpl_compatible(license))
1276                        mod->gpl_compatible = 1;
1277                else {
1278                        mod->gpl_compatible = 0;
1279                        break;
1280                }
1281                license = get_next_modinfo(info.modinfo, info.modinfo_len,
1282                                           "license", license);
1283        }
1284
1285        for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1286                symname = info.strtab + sym->st_name;
1287
1288                handle_modversions(mod, &info, sym, symname);
1289                handle_moddevtable(mod, &info, sym, symname);
1290        }
1291        if (is_vmlinux(modname) && vmlinux_section_warnings) {
1292                check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1293                check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1294        }
1295
1296        version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1297        if (version)
1298                maybe_frob_rcs_version(modname, version, info.modinfo,
1299                                       version - (char *)info.hdr);
1300        if (version || (all_versions && !is_vmlinux(modname)))
1301                get_src_version(modname, mod->srcversion,
1302                                sizeof(mod->srcversion)-1);
1303
1304        parse_elf_finish(&info);
1305
1306        /* Our trick to get versioning for struct_module - it's
1307         * never passed as an argument to an exported function, so
1308         * the automatic versioning doesn't pick it up, but it's really
1309         * important anyhow */
1310        if (modversions)
1311                mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1312}
1313
1314#define SZ 500
1315
1316/* We first write the generated file into memory using the
1317 * following helper, then compare to the file on disk and
1318 * only update the later if anything changed */
1319
1320void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1321                                                      const char *fmt, ...)
1322{
1323        char tmp[SZ];
1324        int len;
1325        va_list ap;
1326
1327        va_start(ap, fmt);
1328        len = vsnprintf(tmp, SZ, fmt, ap);
1329        buf_write(buf, tmp, len);
1330        va_end(ap);
1331}
1332
1333void buf_write(struct buffer *buf, const char *s, int len)
1334{
1335        if (buf->size - buf->pos < len) {
1336                buf->size += len + SZ;
1337                buf->p = realloc(buf->p, buf->size);
1338        }
1339        strncpy(buf->p + buf->pos, s, len);
1340        buf->pos += len;
1341}
1342
1343static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1344{
1345        const char *e = is_vmlinux(m) ?"":".ko";
1346
1347        switch (exp) {
1348        case export_gpl:
1349                fatal("modpost: GPL-incompatible module %s%s "
1350                      "uses GPL-only symbol '%s'\n", m, e, s);
1351                break;
1352        case export_unused_gpl:
1353                fatal("modpost: GPL-incompatible module %s%s "
1354                      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1355                break;
1356        case export_gpl_future:
1357                warn("modpost: GPL-incompatible module %s%s "
1358                      "uses future GPL-only symbol '%s'\n", m, e, s);
1359                break;
1360        case export_plain:
1361        case export_unused:
1362        case export_unknown:
1363                /* ignore */
1364                break;
1365        }
1366}
1367
1368static void check_for_unused(enum export exp, const char* m, const char* s)
1369{
1370        const char *e = is_vmlinux(m) ?"":".ko";
1371
1372        switch (exp) {
1373        case export_unused:
1374        case export_unused_gpl:
1375                warn("modpost: module %s%s "
1376                      "uses symbol '%s' marked UNUSED\n", m, e, s);
1377                break;
1378        default:
1379                /* ignore */
1380                break;
1381        }
1382}
1383
1384static void check_exports(struct module *mod)
1385{
1386        struct symbol *s, *exp;
1387
1388        for (s = mod->unres; s; s = s->next) {
1389                const char *basename;
1390                exp = find_symbol(s->name);
1391                if (!exp || exp->module == mod)
1392                        continue;
1393                basename = strrchr(mod->name, '/');
1394                if (basename)
1395                        basename++;
1396                else
1397                        basename = mod->name;
1398                if (!mod->gpl_compatible)
1399                        check_for_gpl_usage(exp->export, basename, exp->name);
1400                check_for_unused(exp->export, basename, exp->name);
1401        }
1402}
1403
1404/**
1405 * Header for the generated file
1406 **/
1407static void add_header(struct buffer *b, struct module *mod)
1408{
1409        buf_printf(b, "#include <linux/module.h>\n");
1410        buf_printf(b, "#include <linux/vermagic.h>\n");
1411        buf_printf(b, "#include <linux/compiler.h>\n");
1412        buf_printf(b, "\n");
1413        buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1414        buf_printf(b, "\n");
1415        buf_printf(b, "struct module __this_module\n");
1416        buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1417        buf_printf(b, " .name = KBUILD_MODNAME,\n");
1418        if (mod->has_init)
1419                buf_printf(b, " .init = init_module,\n");
1420        if (mod->has_cleanup)
1421                buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1422                              " .exit = cleanup_module,\n"
1423                              "#endif\n");
1424        buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1425        buf_printf(b, "};\n");
1426}
1427
1428/**
1429 * Record CRCs for unresolved symbols
1430 **/
1431static int add_versions(struct buffer *b, struct module *mod)
1432{
1433        struct symbol *s, *exp;
1434        int err = 0;
1435
1436        for (s = mod->unres; s; s = s->next) {
1437                exp = find_symbol(s->name);
1438                if (!exp || exp->module == mod) {
1439                        if (have_vmlinux && !s->weak) {
1440                                if (warn_unresolved) {
1441                                        warn("\"%s\" [%s.ko] undefined!\n",
1442                                             s->name, mod->name);
1443                                } else {
1444                                        merror("\"%s\" [%s.ko] undefined!\n",
1445                                                  s->name, mod->name);
1446                                        err = 1;
1447                                }
1448                        }
1449                        continue;
1450                }
1451                s->module = exp->module;
1452                s->crc_valid = exp->crc_valid;
1453                s->crc = exp->crc;
1454        }
1455
1456        if (!modversions)
1457                return err;
1458
1459        buf_printf(b, "\n");
1460        buf_printf(b, "static const struct modversion_info ____versions[]\n");
1461        buf_printf(b, "__attribute_used__\n");
1462        buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1463
1464        for (s = mod->unres; s; s = s->next) {
1465                if (!s->module) {
1466                        continue;
1467                }
1468                if (!s->crc_valid) {
1469                        warn("\"%s\" [%s.ko] has no CRC!\n",
1470                                s->name, mod->name);
1471                        continue;
1472                }
1473                buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1474        }
1475
1476        buf_printf(b, "};\n");
1477
1478        return err;
1479}
1480
1481static void add_depends(struct buffer *b, struct module *mod,
1482                        struct module *modules)
1483{
1484        struct symbol *s;
1485        struct module *m;
1486        int first = 1;
1487
1488        for (m = modules; m; m = m->next) {
1489                m->seen = is_vmlinux(m->name);
1490        }
1491
1492        buf_printf(b, "\n");
1493        buf_printf(b, "static const char __module_depends[]\n");
1494        buf_printf(b, "__attribute_used__\n");
1495        buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1496        buf_printf(b, "\"depends=");
1497        for (s = mod->unres; s; s = s->next) {
1498                const char *p;
1499                if (!s->module)
1500                        continue;
1501
1502                if (s->module->seen)
1503                        continue;
1504
1505                s->module->seen = 1;
1506                if ((p = strrchr(s->module->name, '/')) != NULL)
1507                        p++;
1508                else
1509                        p = s->module->name;
1510                buf_printf(b, "%s%s", first ? "" : ",", p);
1511                first = 0;
1512        }
1513        buf_printf(b, "\";\n");
1514}
1515
1516static void add_srcversion(struct buffer *b, struct module *mod)
1517{
1518        if (mod->srcversion[0]) {
1519                buf_printf(b, "\n");
1520                buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1521                           mod->srcversion);
1522        }
1523}
1524
1525static void write_if_changed(struct buffer *b, const char *fname)
1526{
1527        char *tmp;
1528        FILE *file;
1529        struct stat st;
1530
1531        file = fopen(fname, "r");
1532        if (!file)
1533                goto write;
1534
1535        if (fstat(fileno(file), &st) < 0)
1536                goto close_write;
1537
1538        if (st.st_size != b->pos)
1539                goto close_write;
1540
1541        tmp = NOFAIL(malloc(b->pos));
1542        if (fread(tmp, 1, b->pos, file) != b->pos)
1543                goto free_write;
1544
1545        if (memcmp(tmp, b->p, b->pos) != 0)
1546                goto free_write;
1547
1548        free(tmp);
1549        fclose(file);
1550        return;
1551
1552 free_write:
1553        free(tmp);
1554 close_write:
1555        fclose(file);
1556 write:
1557        file = fopen(fname, "w");
1558        if (!file) {
1559                perror(fname);
1560                exit(1);
1561        }
1562        if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1563                perror(fname);
1564                exit(1);
1565        }
1566        fclose(file);
1567}
1568
1569/* parse Module.symvers file. line format:
1570 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1571 **/
1572static void read_dump(const char *fname, unsigned int kernel)
1573{
1574        unsigned long size, pos = 0;
1575        void *file = grab_file(fname, &size);
1576        char *line;
1577
1578        if (!file)
1579                /* No symbol versions, silently ignore */
1580                return;
1581
1582        while ((line = get_next_line(&pos, file, size))) {
1583                char *symname, *modname, *d, *export, *end;
1584                unsigned int crc;
1585                struct module *mod;
1586                struct symbol *s;
1587
1588                if (!(symname = strchr(line, '\t')))
1589                        goto fail;
1590                *symname++ = '\0';
1591                if (!(modname = strchr(symname, '\t')))
1592                        goto fail;
1593                *modname++ = '\0';
1594                if ((export = strchr(modname, '\t')) != NULL)
1595                        *export++ = '\0';
1596                if (export && ((end = strchr(export, '\t')) != NULL))
1597                        *end = '\0';
1598                crc = strtoul(line, &d, 16);
1599                if (*symname == '\0' || *modname == '\0' || *d != '\0')
1600                        goto fail;
1601
1602                if (!(mod = find_module(modname))) {
1603                        if (is_vmlinux(modname)) {
1604                                have_vmlinux = 1;
1605                        }
1606                        mod = new_module(NOFAIL(strdup(modname)));
1607                        mod->skip = 1;
1608                }
1609                s = sym_add_exported(symname, mod, export_no(export));
1610                s->kernel    = kernel;
1611                s->preloaded = 1;
1612                sym_update_crc(symname, mod, crc, export_no(export));
1613        }
1614        return;
1615fail:
1616        fatal("parse error in symbol dump file\n");
1617}
1618
1619/* For normal builds always dump all symbols.
1620 * For external modules only dump symbols
1621 * that are not read from kernel Module.symvers.
1622 **/
1623static int dump_sym(struct symbol *sym)
1624{
1625        if (!external_module)
1626                return 1;
1627        if (sym->vmlinux || sym->kernel)
1628                return 0;
1629        return 1;
1630}
1631
1632static void write_dump(const char *fname)
1633{
1634        struct buffer buf = { };
1635        struct symbol *symbol;
1636        int n;
1637
1638        for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1639                symbol = symbolhash[n];
1640                while (symbol) {
1641                        if (dump_sym(symbol))
1642                                buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1643                                        symbol->crc, symbol->name,
1644                                        symbol->module->name,
1645                                        export_str(symbol->export));
1646                        symbol = symbol->next;
1647                }
1648        }
1649        write_if_changed(&buf, fname);
1650}
1651
1652int main(int argc, char **argv)
1653{
1654        struct module *mod;
1655        struct buffer buf = { };
1656        char fname[SZ];
1657        char *kernel_read = NULL, *module_read = NULL;
1658        char *dump_write = NULL;
1659        int opt;
1660        int err;
1661
1662        while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) {
1663                switch(opt) {
1664                        case 'i':
1665                                kernel_read = optarg;
1666                                break;
1667                        case 'I':
1668                                module_read = optarg;
1669                                external_module = 1;
1670                                break;
1671                        case 'm':
1672                                modversions = 1;
1673                                break;
1674                        case 'o':
1675                                dump_write = optarg;
1676                                break;
1677                        case 'a':
1678                                all_versions = 1;
1679                                break;
1680                        case 's':
1681                                vmlinux_section_warnings = 0;
1682                                break;
1683                        case 'w':
1684                                warn_unresolved = 1;
1685                                break;
1686                        default:
1687                                exit(1);
1688                }
1689        }
1690
1691        if (kernel_read)
1692                read_dump(kernel_read, 1);
1693        if (module_read)
1694                read_dump(module_read, 0);
1695
1696        while (optind < argc) {
1697                read_symbols(argv[optind++]);
1698        }
1699
1700        for (mod = modules; mod; mod = mod->next) {
1701                if (mod->skip)
1702                        continue;
1703                check_exports(mod);
1704        }
1705
1706        err = 0;
1707
1708        for (mod = modules; mod; mod = mod->next) {
1709                if (mod->skip)
1710                        continue;
1711
1712                buf.pos = 0;
1713
1714                add_header(&buf, mod);
1715                err |= add_versions(&buf, mod);
1716                add_depends(&buf, mod, modules);
1717                add_moddevtable(&buf, mod);
1718                add_srcversion(&buf, mod);
1719
1720                sprintf(fname, "%s.mod.c", mod->name);
1721                write_if_changed(&buf, fname);
1722        }
1723
1724        if (dump_write)
1725                write_dump(dump_write);
1726
1727        return err;
1728}
1729