modpost.c 36.4 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4
/* Postprocess module symbol versions
 *
 * Copyright 2003       Kai Germaschewski
 * Copyright 2002-2004  Rusty Russell, IBM Corporation
5
 * Copyright 2006       Sam Ravnborg
L
Linus Torvalds 已提交
6 7 8 9 10 11 12 13 14 15
 * Based in part on module-init-tools/depmod.c,file2alias
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 * Usage: modpost vmlinux module1.o module2.o ...
 */

#include <ctype.h>
#include "modpost.h"
16
#include "../../include/linux/license.h"
L
Linus Torvalds 已提交
17 18 19 20 21 22 23

/* Are we using CONFIG_MODVERSIONS? */
int modversions = 0;
/* Warn about undefined symbols? (do so if we have vmlinux) */
int have_vmlinux = 0;
/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
static int all_versions = 0;
24 25
/* If we are modposting external module set to 1 */
static int external_module = 0;
26 27
/* Only warn about unresolved symbols */
static int warn_unresolved = 0;
28
/* How a symbol is exported */
29 30 31 32
enum export {
	export_plain,      export_unused,     export_gpl,
	export_unused_gpl, export_gpl_future, export_unknown
};
L
Linus Torvalds 已提交
33

34
void fatal(const char *fmt, ...)
L
Linus Torvalds 已提交
35 36 37 38 39 40 41 42 43 44 45 46
{
	va_list arglist;

	fprintf(stderr, "FATAL: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);

	exit(1);
}

47
void warn(const char *fmt, ...)
L
Linus Torvalds 已提交
48 49 50 51 52 53 54 55 56 57
{
	va_list arglist;

	fprintf(stderr, "WARNING: ");

	va_start(arglist, fmt);
	vfprintf(stderr, fmt, arglist);
	va_end(arglist);
}

58 59 60 61 62 63 64 65 66 67 68 69
static int is_vmlinux(const char *modname)
{
	const char *myname;

	if ((myname = strrchr(modname, '/')))
		myname++;
	else
		myname = modname;

	return strcmp(myname, "vmlinux") == 0;
}

L
Linus Torvalds 已提交
70 71 72 73 74 75 76 77 78 79 80 81
void *do_nofail(void *ptr, const char *expr)
{
	if (!ptr) {
		fatal("modpost: Memory allocation failure: %s.\n", expr);
	}
	return ptr;
}

/* A list of all modules we processed */

static struct module *modules;

82
static struct module *find_module(char *modname)
L
Linus Torvalds 已提交
83 84 85 86 87 88 89 90 91
{
	struct module *mod;

	for (mod = modules; mod; mod = mod->next)
		if (strcmp(mod->name, modname) == 0)
			break;
	return mod;
}

92
static struct module *new_module(char *modname)
L
Linus Torvalds 已提交
93 94 95
{
	struct module *mod;
	char *p, *s;
96

L
Linus Torvalds 已提交
97 98 99 100 101 102 103 104 105 106 107
	mod = NOFAIL(malloc(sizeof(*mod)));
	memset(mod, 0, sizeof(*mod));
	p = NOFAIL(strdup(modname));

	/* strip trailing .o */
	if ((s = strrchr(p, '.')) != NULL)
		if (strcmp(s, ".o") == 0)
			*s = '\0';

	/* add to list */
	mod->name = p;
108
	mod->gpl_compatible = -1;
L
Linus Torvalds 已提交
109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
	mod->next = modules;
	modules = mod;

	return mod;
}

/* A hash of all exported symbols,
 * struct symbol is also used for lists of unresolved symbols */

#define SYMBOL_HASH_SIZE 1024

struct symbol {
	struct symbol *next;
	struct module *module;
	unsigned int crc;
	int crc_valid;
	unsigned int weak:1;
126 127 128
	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
	unsigned int kernel:1;     /* 1 if symbol is from kernel
				    *  (only for external modules) **/
129
	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
130
	enum export  export;       /* Type of export */
L
Linus Torvalds 已提交
131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148
	char name[0];
};

static struct symbol *symbolhash[SYMBOL_HASH_SIZE];

/* This is based on the hash agorithm from gdbm, via tdb */
static inline unsigned int tdb_hash(const char *name)
{
	unsigned value;	/* Used to compute the hash value.  */
	unsigned   i;	/* Used to cycle through random values. */

	/* Set the initial value from the key size. */
	for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));

	return (1103515243 * value + 12345);
}

149 150 151 152 153 154
/**
 * Allocate a new symbols for use in the hash of exported symbols or
 * the list of unresolved symbols per module
 **/
static struct symbol *alloc_symbol(const char *name, unsigned int weak,
				   struct symbol *next)
L
Linus Torvalds 已提交
155 156 157 158 159 160 161 162 163 164 165
{
	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));

	memset(s, 0, sizeof(*s));
	strcpy(s->name, name);
	s->weak = weak;
	s->next = next;
	return s;
}

/* For the hash of exported symbols */
166 167
static struct symbol *new_symbol(const char *name, struct module *module,
				 enum export export)
L
Linus Torvalds 已提交
168 169 170 171 172 173 174
{
	unsigned int hash;
	struct symbol *new;

	hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
	new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
	new->module = module;
175
	new->export = export;
176
	return new;
L
Linus Torvalds 已提交
177 178
}

179
static struct symbol *find_symbol(const char *name)
L
Linus Torvalds 已提交
180 181 182 183 184 185 186 187 188 189 190 191 192 193
{
	struct symbol *s;

	/* For our purposes, .foo matches foo.  PPC64 needs this. */
	if (name[0] == '.')
		name++;

	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
		if (strcmp(s->name, name) == 0)
			return s;
	}
	return NULL;
}

194 195 196 197 198
static struct {
	const char *str;
	enum export export;
} export_list[] = {
	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
199
	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
200
	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
201
	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
202 203 204 205 206 207 208 209 210 211 212 213 214
	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
	{ .str = "(unknown)",                .export = export_unknown },
};


static const char *export_str(enum export ex)
{
	return export_list[ex].str;
}

static enum export export_no(const char * s)
{
	int i;
S
Sam Ravnborg 已提交
215 216
	if (!s)
		return export_unknown;
217 218 219 220 221 222 223 224 225 226 227
	for (i = 0; export_list[i].export != export_unknown; i++) {
		if (strcmp(export_list[i].str, s) == 0)
			return export_list[i].export;
	}
	return export_unknown;
}

static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
{
	if (sec == elf->export_sec)
		return export_plain;
228 229
	else if (sec == elf->export_unused_sec)
		return export_unused;
230 231
	else if (sec == elf->export_gpl_sec)
		return export_gpl;
232 233
	else if (sec == elf->export_unused_gpl_sec)
		return export_unused_gpl;
234 235 236 237 238 239
	else if (sec == elf->export_gpl_future_sec)
		return export_gpl_future;
	else
		return export_unknown;
}

240 241 242 243
/**
 * Add an exported symbol - it may have already been added without a
 * CRC, in this case just update the CRC
 **/
244 245
static struct symbol *sym_add_exported(const char *name, struct module *mod,
				       enum export export)
L
Linus Torvalds 已提交
246 247 248 249
{
	struct symbol *s = find_symbol(name);

	if (!s) {
250
		s = new_symbol(name, mod, export);
251 252
	} else {
		if (!s->preloaded) {
253
			warn("%s: '%s' exported twice. Previous export "
254 255 256 257
			     "was in %s%s\n", mod->name, name,
			     s->module->name,
			     is_vmlinux(s->module->name) ?"":".ko");
		}
L
Linus Torvalds 已提交
258
	}
259
	s->preloaded = 0;
260 261
	s->vmlinux   = is_vmlinux(mod->name);
	s->kernel    = 0;
262
	s->export    = export;
263 264 265 266
	return s;
}

static void sym_update_crc(const char *name, struct module *mod,
267
			   unsigned int crc, enum export export)
268 269 270 271
{
	struct symbol *s = find_symbol(name);

	if (!s)
272
		s = new_symbol(name, mod, export);
273 274
	s->crc = crc;
	s->crc_valid = 1;
L
Linus Torvalds 已提交
275 276
}

277
void *grab_file(const char *filename, unsigned long *size)
L
Linus Torvalds 已提交
278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295
{
	struct stat st;
	void *map;
	int fd;

	fd = open(filename, O_RDONLY);
	if (fd < 0 || fstat(fd, &st) != 0)
		return NULL;

	*size = st.st_size;
	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
	close(fd);

	if (map == MAP_FAILED)
		return NULL;
	return map;
}

296 297 298 299 300 301
/**
  * Return a copy of the next line in a mmap'ed file.
  * spaces in the beginning of the line is trimmed away.
  * Return a pointer to a static buffer.
  **/
char* get_next_line(unsigned long *pos, void *file, unsigned long size)
L
Linus Torvalds 已提交
302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330
{
	static char line[4096];
	int skip = 1;
	size_t len = 0;
	signed char *p = (signed char *)file + *pos;
	char *s = line;

	for (; *pos < size ; (*pos)++)
	{
		if (skip && isspace(*p)) {
			p++;
			continue;
		}
		skip = 0;
		if (*p != '\n' && (*pos < size)) {
			len++;
			*s++ = *p++;
			if (len > 4095)
				break; /* Too long, stop */
		} else {
			/* End of string */
			*s = '\0';
			return line;
		}
	}
	/* End of buffer */
	return NULL;
}

331
void release_file(void *file, unsigned long size)
L
Linus Torvalds 已提交
332 333 334 335
{
	munmap(file, size);
}

336
static void parse_elf(struct elf_info *info, const char *filename)
L
Linus Torvalds 已提交
337 338 339 340 341 342 343 344 345
{
	unsigned int i;
	Elf_Ehdr *hdr = info->hdr;
	Elf_Shdr *sechdrs;
	Elf_Sym  *sym;

	hdr = grab_file(filename, &info->size);
	if (!hdr) {
		perror(filename);
346
		exit(1);
L
Linus Torvalds 已提交
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371
	}
	info->hdr = hdr;
	if (info->size < sizeof(*hdr))
		goto truncated;

	/* Fix endianness in ELF header */
	hdr->e_shoff    = TO_NATIVE(hdr->e_shoff);
	hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
	hdr->e_shnum    = TO_NATIVE(hdr->e_shnum);
	hdr->e_machine  = TO_NATIVE(hdr->e_machine);
	sechdrs = (void *)hdr + hdr->e_shoff;
	info->sechdrs = sechdrs;

	/* Fix endianness in section headers */
	for (i = 0; i < hdr->e_shnum; i++) {
		sechdrs[i].sh_type   = TO_NATIVE(sechdrs[i].sh_type);
		sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
		sechdrs[i].sh_size   = TO_NATIVE(sechdrs[i].sh_size);
		sechdrs[i].sh_link   = TO_NATIVE(sechdrs[i].sh_link);
		sechdrs[i].sh_name   = TO_NATIVE(sechdrs[i].sh_name);
	}
	/* Find symbol table. */
	for (i = 1; i < hdr->e_shnum; i++) {
		const char *secstrings
			= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
372
		const char *secname;
L
Linus Torvalds 已提交
373 374 375

		if (sechdrs[i].sh_offset > info->size)
			goto truncated;
376 377
		secname = secstrings + sechdrs[i].sh_name;
		if (strcmp(secname, ".modinfo") == 0) {
L
Linus Torvalds 已提交
378 379
			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
			info->modinfo_len = sechdrs[i].sh_size;
380 381
		} else if (strcmp(secname, "__ksymtab") == 0)
			info->export_sec = i;
382 383
		else if (strcmp(secname, "__ksymtab_unused") == 0)
			info->export_unused_sec = i;
384 385
		else if (strcmp(secname, "__ksymtab_gpl") == 0)
			info->export_gpl_sec = i;
386 387
		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
			info->export_unused_gpl_sec = i;
388 389 390
		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
			info->export_gpl_future_sec = i;

L
Linus Torvalds 已提交
391 392 393 394
		if (sechdrs[i].sh_type != SHT_SYMTAB)
			continue;

		info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
395
		info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset
L
Linus Torvalds 已提交
396
			                         + sechdrs[i].sh_size;
397
		info->strtab       = (void *)hdr +
L
Linus Torvalds 已提交
398 399 400
			             sechdrs[sechdrs[i].sh_link].sh_offset;
	}
	if (!info->symtab_start) {
401
		fatal("%s has no symtab?\n", filename);
L
Linus Torvalds 已提交
402 403 404 405 406 407 408 409 410 411 412
	}
	/* Fix endianness in symbols */
	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
		sym->st_shndx = TO_NATIVE(sym->st_shndx);
		sym->st_name  = TO_NATIVE(sym->st_name);
		sym->st_value = TO_NATIVE(sym->st_value);
		sym->st_size  = TO_NATIVE(sym->st_size);
	}
	return;

 truncated:
413
	fatal("%s is truncated.\n", filename);
L
Linus Torvalds 已提交
414 415
}

416
static void parse_elf_finish(struct elf_info *info)
L
Linus Torvalds 已提交
417 418 419 420
{
	release_file(info->hdr, info->size);
}

421 422
#define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
L
Linus Torvalds 已提交
423

424 425
static void handle_modversions(struct module *mod, struct elf_info *info,
			       Elf_Sym *sym, const char *symname)
L
Linus Torvalds 已提交
426 427
{
	unsigned int crc;
428
	enum export export = export_from_sec(info, sym->st_shndx);
L
Linus Torvalds 已提交
429 430 431

	switch (sym->st_shndx) {
	case SHN_COMMON:
432
		warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
L
Linus Torvalds 已提交
433 434 435 436 437
		break;
	case SHN_ABS:
		/* CRC'd symbol */
		if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
			crc = (unsigned int) sym->st_value;
438 439
			sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
					export);
L
Linus Torvalds 已提交
440 441 442 443 444 445 446 447 448 449 450 451 452
		}
		break;
	case SHN_UNDEF:
		/* undefined symbol */
		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
			break;
		/* ignore global offset table */
		if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
			break;
		/* ignore __this_module, it will be resolved shortly */
		if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
			break;
453 454 455 456 457 458
/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
/* add compatibility with older glibc */
#ifndef STT_SPARC_REGISTER
#define STT_SPARC_REGISTER STT_REGISTER
#endif
L
Linus Torvalds 已提交
459 460 461
		if (info->hdr->e_machine == EM_SPARC ||
		    info->hdr->e_machine == EM_SPARCV9) {
			/* Ignore register directives. */
462
			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
L
Linus Torvalds 已提交
463
				break;
464 465 466 467 468 469
			if (symname[0] == '.') {
				char *munged = strdup(symname);
				munged[0] = '_';
				munged[1] = toupper(munged[1]);
				symname = munged;
			}
L
Linus Torvalds 已提交
470 471
		}
#endif
472

L
Linus Torvalds 已提交
473 474 475 476 477 478 479 480 481 482
		if (memcmp(symname, MODULE_SYMBOL_PREFIX,
			   strlen(MODULE_SYMBOL_PREFIX)) == 0)
			mod->unres = alloc_symbol(symname +
						  strlen(MODULE_SYMBOL_PREFIX),
						  ELF_ST_BIND(sym->st_info) == STB_WEAK,
						  mod->unres);
		break;
	default:
		/* All exported symbols */
		if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
483 484
			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
					export);
L
Linus Torvalds 已提交
485 486 487 488 489 490 491 492 493
		}
		if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
			mod->has_init = 1;
		if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
			mod->has_cleanup = 1;
		break;
	}
}

494 495 496
/**
 * Parse tag=value strings from .modinfo section
 **/
L
Linus Torvalds 已提交
497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514
static char *next_string(char *string, unsigned long *secsize)
{
	/* Skip non-zero chars */
	while (string[0]) {
		string++;
		if ((*secsize)-- <= 1)
			return NULL;
	}

	/* Skip any zero padding. */
	while (!string[0]) {
		string++;
		if ((*secsize)-- <= 1)
			return NULL;
	}
	return string;
}

515 516
static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
			      const char *tag, char *info)
L
Linus Torvalds 已提交
517 518 519 520 521
{
	char *p;
	unsigned int taglen = strlen(tag);
	unsigned long size = modinfo_len;

522 523 524 525 526
	if (info) {
		size -= info - (char *)modinfo;
		modinfo = next_string(info, &size);
	}

L
Linus Torvalds 已提交
527 528 529 530 531 532 533
	for (p = modinfo; p; p = next_string(p, &size)) {
		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
			return p + taglen + 1;
	}
	return NULL;
}

534 535 536 537 538 539 540
static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
			 const char *tag)

{
	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
}

541 542 543 544 545 546 547
/**
 * Test if string s ends in string sub
 * return 0 if match
 **/
static int strrcmp(const char *s, const char *sub)
{
        int slen, sublen;
548

549 550
	if (!s || !sub)
		return 1;
551

552 553
	slen = strlen(s);
        sublen = strlen(sub);
554

555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572
	if ((slen == 0) || (sublen == 0))
		return 1;

        if (sublen > slen)
                return 1;

        return memcmp(s + slen - sublen, sub, sublen);
}

/**
 * Whitelist to allow certain references to pass with no warning.
 * Pattern 1:
 *   If a module parameter is declared __initdata and permissions=0
 *   then this is legal despite the warning generated.
 *   We cannot see value of permissions here, so just ignore
 *   this pattern.
 *   The pattern is identified by:
 *   tosec   = .init.data
573
 *   fromsec = .data*
574
 *   atsym   =__param*
575
 *
576
 * Pattern 2:
577
 *   Many drivers utilise a *driver container with references to
578 579 580 581
 *   add, remove, probe functions etc.
 *   These functions may often be marked __init and we do not want to
 *   warn here.
 *   the pattern is identified by:
582
 *   tosec   = .init.text | .exit.text | .init.data
583
 *   fromsec = .data
584
 *   atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one
585
 **/
586 587
static int secref_whitelist(const char *modname, const char *tosec,
			    const char *fromsec, const char *atsym)
588 589 590 591
{
	int f1 = 1, f2 = 1;
	const char **s;
	const char *pat2sym[] = {
592
		"driver",
593 594
		"_template", /* scsi uses *_template a lot */
		"_sht",      /* scsi also used *_sht to some extent */
595 596 597 598 599
		"_ops",
		"_probe",
		"_probe_one",
		NULL
	};
600

601 602 603
	/* Check for pattern 1 */
	if (strcmp(tosec, ".init.data") != 0)
		f1 = 0;
604
	if (strncmp(fromsec, ".data", strlen(".data")) != 0)
605 606 607 608 609 610 611 612
		f1 = 0;
	if (strncmp(atsym, "__param", strlen("__param")) != 0)
		f1 = 0;

	if (f1)
		return f1;

	/* Check for pattern 2 */
613
	if ((strcmp(tosec, ".init.text") != 0) &&
614 615
	    (strcmp(tosec, ".exit.text") != 0) &&
	    (strcmp(tosec, ".init.data") != 0))
616 617 618 619 620 621 622
		f2 = 0;
	if (strcmp(fromsec, ".data") != 0)
		f2 = 0;

	for (s = pat2sym; *s; s++)
		if (strrcmp(atsym, *s) == 0)
			f1 = 1;
623 624
	if (f1 && f2)
		return 1;
625

626 627 628 629 630 631
	/* Whitelist all references from .pci_fixup section if vmlinux */
	if (is_vmlinux(modname)) {
		if ((strcmp(fromsec, ".pci_fixup") == 0) &&
		    (strcmp(tosec, ".init.text") == 0))
		return 1;
	}
632
	return 0;
633 634
}

635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657
/**
 * Find symbol based on relocation record info.
 * In some cases the symbol supplied is a valid symbol so
 * return refsym. If st_name != 0 we assume this is a valid symbol.
 * In other cases the symbol needs to be looked up in the symbol table
 * based on section and address.
 *  **/
static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
				Elf_Sym *relsym)
{
	Elf_Sym *sym;

	if (relsym->st_name != 0)
		return relsym;
	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
		if (sym->st_shndx != relsym->st_shndx)
			continue;
		if (sym->st_value == addr)
			return sym;
	}
	return NULL;
}

658
/*
659 660 661 662
 * Find symbols before or equal addr and after addr - in the section sec.
 * If we find two symbols with equal offset prefer one with a valid name.
 * The ELF format may have a better way to detect what type of symbol
 * it is, but this works for now.
663 664 665 666 667 668 669 670 671 672 673
 **/
static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
				 const char *sec,
			         Elf_Sym **before, Elf_Sym **after)
{
	Elf_Sym *sym;
	Elf_Ehdr *hdr = elf->hdr;
	Elf_Addr beforediff = ~0;
	Elf_Addr afterdiff = ~0;
	const char *secstrings = (void *)hdr +
				 elf->sechdrs[hdr->e_shstrndx].sh_offset;
674

675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
	*before = NULL;
	*after = NULL;

	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
		const char *symsec;

		if (sym->st_shndx >= SHN_LORESERVE)
			continue;
		symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
		if (strcmp(symsec, sec) != 0)
			continue;
		if (sym->st_value <= addr) {
			if ((addr - sym->st_value) < beforediff) {
				beforediff = addr - sym->st_value;
				*before = sym;
			}
691 692 693 694 695 696
			else if ((addr - sym->st_value) == beforediff) {
				/* equal offset, valid name? */
				const char *name = elf->strtab + sym->st_name;
				if (name && strlen(name))
					*before = sym;
			}
697 698 699 700 701 702 703
		}
		else
		{
			if ((sym->st_value - addr) < afterdiff) {
				afterdiff = sym->st_value - addr;
				*after = sym;
			}
704 705 706 707 708 709
			else if ((sym->st_value - addr) == afterdiff) {
				/* equal offset, valid name? */
				const char *name = elf->strtab + sym->st_name;
				if (name && strlen(name))
					*after = sym;
			}
710 711 712 713 714 715 716
		}
	}
}

/**
 * Print a warning about a section mismatch.
 * Try to find symbols near it so user can find it.
717
 * Check whitelist before warning - it may be a false positive.
718 719 720 721
 **/
static void warn_sec_mismatch(const char *modname, const char *fromsec,
			      struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
{
722 723 724
	const char *refsymname = "";
	Elf_Sym *before, *after;
	Elf_Sym *refsym;
725 726 727 728 729
	Elf_Ehdr *hdr = elf->hdr;
	Elf_Shdr *sechdrs = elf->sechdrs;
	const char *secstrings = (void *)hdr +
				 sechdrs[hdr->e_shstrndx].sh_offset;
	const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
730

731 732
	find_symbols_between(elf, r.r_offset, fromsec, &before, &after);

733 734 735
	refsym = find_elf_symbol(elf, r.r_addend, sym);
	if (refsym && strlen(elf->strtab + refsym->st_name))
		refsymname = elf->strtab + refsym->st_name;
736 737

	/* check whitelist - we may ignore it */
738
	if (before &&
739 740
	    secref_whitelist(modname, secname, fromsec,
			     elf->strtab + before->st_name))
741
		return;
742

743
	if (before && after) {
744 745 746
		warn("%s - Section mismatch: reference to %s:%s from %s "
		     "between '%s' (at offset 0x%llx) and '%s'\n",
		     modname, secname, refsymname, fromsec,
747
		     elf->strtab + before->st_name,
748
		     (long long)r.r_offset,
749 750
		     elf->strtab + after->st_name);
	} else if (before) {
751 752
		warn("%s - Section mismatch: reference to %s:%s from %s "
		     "after '%s' (at offset 0x%llx)\n",
753
		     modname, secname, refsymname, fromsec,
754
		     elf->strtab + before->st_name,
755
		     (long long)r.r_offset);
756
	} else if (after) {
757 758
		warn("%s - Section mismatch: reference to %s:%s from %s "
		     "before '%s' (at offset -0x%llx)\n",
759
		     modname, secname, refsymname, fromsec,
760
		     elf->strtab + after->st_name,
761
		     (long long)r.r_offset);
762
	} else {
763 764 765 766
		warn("%s - Section mismatch: reference to %s:%s from %s "
		     "(offset 0x%llx)\n",
		     modname, secname, fromsec, refsymname,
		     (long long)r.r_offset);
767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792
	}
}

/**
 * A module includes a number of sections that are discarded
 * either when loaded or when used as built-in.
 * For loaded modules all functions marked __init and all data
 * marked __initdata will be discarded when the module has been intialized.
 * Likewise for modules used built-in the sections marked __exit
 * are discarded because __exit marked function are supposed to be called
 * only when a moduel is unloaded which never happes for built-in modules.
 * The check_sec_ref() function traverses all relocation records
 * to find all references to a section that reference a section that will
 * be discarded and warns about it.
 **/
static void check_sec_ref(struct module *mod, const char *modname,
			  struct elf_info *elf,
			  int section(const char*),
			  int section_ref_ok(const char *))
{
	int i;
	Elf_Sym  *sym;
	Elf_Ehdr *hdr = elf->hdr;
	Elf_Shdr *sechdrs = elf->sechdrs;
	const char *secstrings = (void *)hdr +
				 sechdrs[hdr->e_shstrndx].sh_offset;
793

794 795
	/* Walk through all sections */
	for (i = 0; i < hdr->e_shnum; i++) {
796 797 798
		const char *name = secstrings + sechdrs[i].sh_name;
		const char *secname;
		Elf_Rela r;
799
		unsigned int r_sym;
800
		/* We want to process only relocation sections and not .init */
801 802 803 804 805 806 807
		if (sechdrs[i].sh_type == SHT_RELA) {
			Elf_Rela *rela;
			Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
			Elf_Rela *stop  = (void*)start + sechdrs[i].sh_size;
			name += strlen(".rela");
			if (section_ref_ok(name))
				continue;
808

809 810
			for (rela = start; rela < stop; rela++) {
				r.r_offset = TO_NATIVE(rela->r_offset);
811 812 813 814 815 816 817 818 819 820 821 822
#if KERNEL_ELFCLASS == ELFCLASS64
				if (hdr->e_machine == EM_MIPS) {
					r_sym = ELF64_MIPS_R_SYM(rela->r_info);
					r_sym = TO_NATIVE(r_sym);
				} else {
					r.r_info = TO_NATIVE(rela->r_info);
					r_sym = ELF_R_SYM(r.r_info);
				}
#else
				r.r_info = TO_NATIVE(rela->r_info);
				r_sym = ELF_R_SYM(r.r_info);
#endif
823
				r.r_addend = TO_NATIVE(rela->r_addend);
824
				sym = elf->symtab_start + r_sym;
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840
				/* Skip special sections */
				if (sym->st_shndx >= SHN_LORESERVE)
					continue;

				secname = secstrings +
					sechdrs[sym->st_shndx].sh_name;
				if (section(secname))
					warn_sec_mismatch(modname, name,
							  elf, sym, r);
			}
		} else if (sechdrs[i].sh_type == SHT_REL) {
			Elf_Rel *rel;
			Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
			Elf_Rel *stop  = (void*)start + sechdrs[i].sh_size;
			name += strlen(".rel");
			if (section_ref_ok(name))
841 842
				continue;

843 844
			for (rel = start; rel < stop; rel++) {
				r.r_offset = TO_NATIVE(rel->r_offset);
845 846 847 848 849 850 851 852 853 854 855 856
#if KERNEL_ELFCLASS == ELFCLASS64
				if (hdr->e_machine == EM_MIPS) {
					r_sym = ELF64_MIPS_R_SYM(rel->r_info);
					r_sym = TO_NATIVE(r_sym);
				} else {
					r.r_info = TO_NATIVE(rel->r_info);
					r_sym = ELF_R_SYM(r.r_info);
				}
#else
				r.r_info = TO_NATIVE(rel->r_info);
				r_sym = ELF_R_SYM(r.r_info);
#endif
857
				r.r_addend = 0;
858
				sym = elf->symtab_start + r_sym;
859 860 861 862 863 864 865 866 867 868
				/* Skip special sections */
				if (sym->st_shndx >= SHN_LORESERVE)
					continue;

				secname = secstrings +
					sechdrs[sym->st_shndx].sh_name;
				if (section(secname))
					warn_sec_mismatch(modname, name,
							  elf, sym, r);
			}
869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890
		}
	}
}

/**
 * Functions used only during module init is marked __init and is stored in
 * a .init.text section. Likewise data is marked __initdata and stored in
 * a .init.data section.
 * If this section is one of these sections return 1
 * See include/linux/init.h for the details
 **/
static int init_section(const char *name)
{
	if (strcmp(name, ".init") == 0)
		return 1;
	if (strncmp(name, ".init.", strlen(".init.")) == 0)
		return 1;
	return 0;
}

/**
 * Identify sections from which references to a .init section is OK.
891
 *
892 893 894 895 896
 * Unfortunately references to read only data that referenced .init
 * sections had to be excluded. Almost all of these are false
 * positives, they are created by gcc. The downside of excluding rodata
 * is that there really are some user references from rodata to
 * init code, e.g. drivers/video/vgacon.c:
897
 *
898 899 900 901 902 903 904 905 906 907 908 909
 * const struct consw vga_con = {
 *        con_startup:            vgacon_startup,
 *
 * where vgacon_startup is __init.  If you want to wade through the false
 * positives, take out the check for rodata.
 **/
static int init_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
		".init",
910 911
		".opd",   /* see comment [OPD] at exit_section_ref_ok() */
		".toc1",  /* used by ppc64 */
912 913
		".stab",
		".rodata",
914
		".parainstructions",
915
		".text.lock",
916
		"__bug_table", /* used by powerpc for BUG() */
917 918 919 920
		".pci_fixup_header",
		".pci_fixup_final",
		".pdr",
		"__param",
921 922
		"__ex_table",
		".fixup",
923
		".smp_locks",
924
		".plt",  /* seen on ARCH=um build on x86_64. Harmless */
925 926
		"__ftr_fixup",		/* powerpc cpu feature fixup */
		"__fw_ftr_fixup",	/* powerpc firmware feature fixup */
927 928 929 930 931 932 933 934
		NULL
	};
	/* Start of section names */
	const char *namelist2[] = {
		".init.",
		".altinstructions",
		".eh_frame",
		".debug",
935
		".parainstructions",
936 937
		NULL
	};
938 939 940 941 942 943
	/* part of section name */
	const char *namelist3 [] = {
		".unwind",  /* sample: IA_64.unwind.init.text */
		NULL
	};

944 945 946
	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
947
	for (s = namelist2; *s; s++)
948 949
		if (strncmp(*s, name, strlen(*s)) == 0)
			return 1;
950
	for (s = namelist3; *s; s++)
951
		if (strstr(name, *s) != NULL)
952
			return 1;
953 954
	if (strrcmp(name, ".init") == 0)
		return 1;
955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971
	return 0;
}

/*
 * Functions used only during module exit is marked __exit and is stored in
 * a .exit.text section. Likewise data is marked __exitdata and stored in
 * a .exit.data section.
 * If this section is one of these sections return 1
 * See include/linux/init.h for the details
 **/
static int exit_section(const char *name)
{
	if (strcmp(name, ".exit.text") == 0)
		return 1;
	if (strcmp(name, ".exit.data") == 0)
		return 1;
	return 0;
972

973 974 975 976
}

/*
 * Identify sections from which references to a .exit section is OK.
977
 *
978 979 980 981
 * [OPD] Keith Ownes <kaos@sgi.com> commented:
 * For our future {in}sanity, add a comment that this is the ppc .opd
 * section, not the ia64 .opd section.
 * ia64 .opd should not point to discarded sections.
982
 * [.rodata] like for .init.text we ignore .rodata references -same reason
983 984 985 986 987 988 989 990 991
 **/
static int exit_section_ref_ok(const char *name)
{
	const char **s;
	/* Absolute section names */
	const char *namelist1[] = {
		".exit.text",
		".exit.data",
		".init.text",
992
		".rodata",
993
		".opd", /* See comment [OPD] */
994
		".toc1",  /* used by ppc64 */
995 996
		".altinstructions",
		".pdr",
997
		"__bug_table", /* used by powerpc for BUG() */
998 999 1000
		".exitcall.exit",
		".eh_frame",
		".stab",
1001 1002
		"__ex_table",
		".fixup",
1003
		".smp_locks",
1004
		".plt",  /* seen on ARCH=um build on x86_64. Harmless */
1005 1006 1007 1008 1009 1010 1011
		NULL
	};
	/* Start of section names */
	const char *namelist2[] = {
		".debug",
		NULL
	};
1012 1013 1014 1015 1016
	/* part of section name */
	const char *namelist3 [] = {
		".unwind",  /* Sample: IA_64.unwind.exit.text */
		NULL
	};
1017

1018 1019 1020
	for (s = namelist1; *s; s++)
		if (strcmp(*s, name) == 0)
			return 1;
1021
	for (s = namelist2; *s; s++)
1022 1023
		if (strncmp(*s, name, strlen(*s)) == 0)
			return 1;
1024
	for (s = namelist3; *s; s++)
1025
		if (strstr(name, *s) != NULL)
1026
			return 1;
1027 1028 1029
	return 0;
}

1030
static void read_symbols(char *modname)
L
Linus Torvalds 已提交
1031 1032 1033
{
	const char *symname;
	char *version;
1034
	char *license;
L
Linus Torvalds 已提交
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049
	struct module *mod;
	struct elf_info info = { };
	Elf_Sym *sym;

	parse_elf(&info, modname);

	mod = new_module(modname);

	/* When there's no vmlinux, don't print warnings about
	 * unresolved symbols (since there'll be too many ;) */
	if (is_vmlinux(modname)) {
		have_vmlinux = 1;
		mod->skip = 1;
	}

1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
	license = get_modinfo(info.modinfo, info.modinfo_len, "license");
	while (license) {
		if (license_is_gpl_compatible(license))
			mod->gpl_compatible = 1;
		else {
			mod->gpl_compatible = 0;
			break;
		}
		license = get_next_modinfo(info.modinfo, info.modinfo_len,
					   "license", license);
	}

L
Linus Torvalds 已提交
1062 1063 1064 1065 1066 1067
	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
		symname = info.strtab + sym->st_name;

		handle_modversions(mod, &info, sym, symname);
		handle_moddevtable(mod, &info, sym, symname);
	}
1068 1069
	check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
	check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
L
Linus Torvalds 已提交
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094

	version = get_modinfo(info.modinfo, info.modinfo_len, "version");
	if (version)
		maybe_frob_rcs_version(modname, version, info.modinfo,
				       version - (char *)info.hdr);
	if (version || (all_versions && !is_vmlinux(modname)))
		get_src_version(modname, mod->srcversion,
				sizeof(mod->srcversion)-1);

	parse_elf_finish(&info);

	/* Our trick to get versioning for struct_module - it's
	 * never passed as an argument to an exported function, so
	 * the automatic versioning doesn't pick it up, but it's really
	 * important anyhow */
	if (modversions)
		mod->unres = alloc_symbol("struct_module", 0, mod->unres);
}

#define SZ 500

/* We first write the generated file into memory using the
 * following helper, then compare to the file on disk and
 * only update the later if anything changed */

1095 1096
void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
						      const char *fmt, ...)
L
Linus Torvalds 已提交
1097 1098 1099 1100
{
	char tmp[SZ];
	int len;
	va_list ap;
1101

L
Linus Torvalds 已提交
1102 1103
	va_start(ap, fmt);
	len = vsnprintf(tmp, SZ, fmt, ap);
1104
	buf_write(buf, tmp, len);
L
Linus Torvalds 已提交
1105 1106 1107
	va_end(ap);
}

1108
void buf_write(struct buffer *buf, const char *s, int len)
L
Linus Torvalds 已提交
1109 1110
{
	if (buf->size - buf->pos < len) {
1111
		buf->size += len + SZ;
L
Linus Torvalds 已提交
1112 1113 1114 1115 1116 1117
		buf->p = realloc(buf->p, buf->size);
	}
	strncpy(buf->p + buf->pos, s, len);
	buf->pos += len;
}

1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159
static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
{
	const char *e = is_vmlinux(m) ?"":".ko";

	switch (exp) {
	case export_gpl:
		fatal("modpost: GPL-incompatible module %s%s "
		      "uses GPL-only symbol '%s'\n", m, e, s);
		break;
	case export_unused_gpl:
		fatal("modpost: GPL-incompatible module %s%s "
		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
		break;
	case export_gpl_future:
		warn("modpost: GPL-incompatible module %s%s "
		      "uses future GPL-only symbol '%s'\n", m, e, s);
		break;
	case export_plain:
	case export_unused:
	case export_unknown:
		/* ignore */
		break;
	}
}

static void check_for_unused(enum export exp, const char* m, const char* s)
{
	const char *e = is_vmlinux(m) ?"":".ko";

	switch (exp) {
	case export_unused:
	case export_unused_gpl:
		warn("modpost: module %s%s "
		      "uses symbol '%s' marked UNUSED\n", m, e, s);
		break;
	default:
		/* ignore */
		break;
	}
}

static void check_exports(struct module *mod)
1160 1161 1162 1163
{
	struct symbol *s, *exp;

	for (s = mod->unres; s; s = s->next) {
A
Andrew Morton 已提交
1164
		const char *basename;
1165 1166 1167
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod)
			continue;
A
Andrew Morton 已提交
1168
		basename = strrchr(mod->name, '/');
1169 1170
		if (basename)
			basename++;
1171 1172 1173 1174 1175
		else
			basename = mod->name;
		if (!mod->gpl_compatible)
			check_for_gpl_usage(exp->export, basename, exp->name);
		check_for_unused(exp->export, basename, exp->name);
1176 1177 1178
        }
}

1179 1180 1181 1182
/**
 * Header for the generated file
 **/
static void add_header(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1183 1184 1185 1186 1187 1188 1189 1190 1191
{
	buf_printf(b, "#include <linux/module.h>\n");
	buf_printf(b, "#include <linux/vermagic.h>\n");
	buf_printf(b, "#include <linux/compiler.h>\n");
	buf_printf(b, "\n");
	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
	buf_printf(b, "\n");
	buf_printf(b, "struct module __this_module\n");
	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1192
	buf_printf(b, " .name = KBUILD_MODNAME,\n");
L
Linus Torvalds 已提交
1193 1194 1195 1196 1197 1198 1199 1200 1201
	if (mod->has_init)
		buf_printf(b, " .init = init_module,\n");
	if (mod->has_cleanup)
		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
			      " .exit = cleanup_module,\n"
			      "#endif\n");
	buf_printf(b, "};\n");
}

1202 1203 1204
/**
 * Record CRCs for unresolved symbols
 **/
1205
static int add_versions(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1206 1207
{
	struct symbol *s, *exp;
1208
	int err = 0;
L
Linus Torvalds 已提交
1209 1210 1211 1212

	for (s = mod->unres; s; s = s->next) {
		exp = find_symbol(s->name);
		if (!exp || exp->module == mod) {
1213
			if (have_vmlinux && !s->weak) {
1214 1215
				warn("\"%s\" [%s.ko] undefined!\n",
				     s->name, mod->name);
1216 1217
				err = warn_unresolved ? 0 : 1;
			}
L
Linus Torvalds 已提交
1218 1219 1220 1221 1222 1223 1224 1225
			continue;
		}
		s->module = exp->module;
		s->crc_valid = exp->crc_valid;
		s->crc = exp->crc;
	}

	if (!modversions)
1226
		return err;
L
Linus Torvalds 已提交
1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237

	buf_printf(b, "\n");
	buf_printf(b, "static const struct modversion_info ____versions[]\n");
	buf_printf(b, "__attribute_used__\n");
	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");

	for (s = mod->unres; s; s = s->next) {
		if (!s->module) {
			continue;
		}
		if (!s->crc_valid) {
1238
			warn("\"%s\" [%s.ko] has no CRC!\n",
L
Linus Torvalds 已提交
1239 1240 1241 1242 1243 1244 1245
				s->name, mod->name);
			continue;
		}
		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
	}

	buf_printf(b, "};\n");
1246 1247

	return err;
L
Linus Torvalds 已提交
1248 1249
}

1250 1251
static void add_depends(struct buffer *b, struct module *mod,
			struct module *modules)
L
Linus Torvalds 已提交
1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280
{
	struct symbol *s;
	struct module *m;
	int first = 1;

	for (m = modules; m; m = m->next) {
		m->seen = is_vmlinux(m->name);
	}

	buf_printf(b, "\n");
	buf_printf(b, "static const char __module_depends[]\n");
	buf_printf(b, "__attribute_used__\n");
	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
	buf_printf(b, "\"depends=");
	for (s = mod->unres; s; s = s->next) {
		if (!s->module)
			continue;

		if (s->module->seen)
			continue;

		s->module->seen = 1;
		buf_printf(b, "%s%s", first ? "" : ",",
			   strrchr(s->module->name, '/') + 1);
		first = 0;
	}
	buf_printf(b, "\";\n");
}

1281
static void add_srcversion(struct buffer *b, struct module *mod)
L
Linus Torvalds 已提交
1282 1283 1284 1285 1286 1287 1288 1289
{
	if (mod->srcversion[0]) {
		buf_printf(b, "\n");
		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
			   mod->srcversion);
	}
}

1290
static void write_if_changed(struct buffer *b, const char *fname)
L
Linus Torvalds 已提交
1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333
{
	char *tmp;
	FILE *file;
	struct stat st;

	file = fopen(fname, "r");
	if (!file)
		goto write;

	if (fstat(fileno(file), &st) < 0)
		goto close_write;

	if (st.st_size != b->pos)
		goto close_write;

	tmp = NOFAIL(malloc(b->pos));
	if (fread(tmp, 1, b->pos, file) != b->pos)
		goto free_write;

	if (memcmp(tmp, b->p, b->pos) != 0)
		goto free_write;

	free(tmp);
	fclose(file);
	return;

 free_write:
	free(tmp);
 close_write:
	fclose(file);
 write:
	file = fopen(fname, "w");
	if (!file) {
		perror(fname);
		exit(1);
	}
	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
		perror(fname);
		exit(1);
	}
	fclose(file);
}

1334
/* parse Module.symvers file. line format:
S
Sam Ravnborg 已提交
1335
 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1336
 **/
1337
static void read_dump(const char *fname, unsigned int kernel)
L
Linus Torvalds 已提交
1338 1339 1340 1341 1342 1343 1344 1345 1346 1347
{
	unsigned long size, pos = 0;
	void *file = grab_file(fname, &size);
	char *line;

        if (!file)
		/* No symbol versions, silently ignore */
		return;

	while ((line = get_next_line(&pos, file, size))) {
S
Sam Ravnborg 已提交
1348
		char *symname, *modname, *d, *export, *end;
L
Linus Torvalds 已提交
1349 1350
		unsigned int crc;
		struct module *mod;
1351
		struct symbol *s;
L
Linus Torvalds 已提交
1352 1353 1354 1355 1356 1357 1358

		if (!(symname = strchr(line, '\t')))
			goto fail;
		*symname++ = '\0';
		if (!(modname = strchr(symname, '\t')))
			goto fail;
		*modname++ = '\0';
1359
		if ((export = strchr(modname, '\t')) != NULL)
1360
			*export++ = '\0';
S
Sam Ravnborg 已提交
1361 1362
		if (export && ((end = strchr(export, '\t')) != NULL))
			*end = '\0';
L
Linus Torvalds 已提交
1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373
		crc = strtoul(line, &d, 16);
		if (*symname == '\0' || *modname == '\0' || *d != '\0')
			goto fail;

		if (!(mod = find_module(modname))) {
			if (is_vmlinux(modname)) {
				have_vmlinux = 1;
			}
			mod = new_module(NOFAIL(strdup(modname)));
			mod->skip = 1;
		}
1374
		s = sym_add_exported(symname, mod, export_no(export));
1375 1376
		s->kernel    = kernel;
		s->preloaded = 1;
1377
		sym_update_crc(symname, mod, crc, export_no(export));
L
Linus Torvalds 已提交
1378 1379 1380 1381 1382 1383
	}
	return;
fail:
	fatal("parse error in symbol dump file\n");
}

1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395
/* For normal builds always dump all symbols.
 * For external modules only dump symbols
 * that are not read from kernel Module.symvers.
 **/
static int dump_sym(struct symbol *sym)
{
	if (!external_module)
		return 1;
	if (sym->vmlinux || sym->kernel)
		return 0;
	return 1;
}
1396

1397
static void write_dump(const char *fname)
L
Linus Torvalds 已提交
1398 1399 1400 1401 1402 1403 1404 1405
{
	struct buffer buf = { };
	struct symbol *symbol;
	int n;

	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
		symbol = symbolhash[n];
		while (symbol) {
1406
			if (dump_sym(symbol))
1407
				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1408
					symbol->crc, symbol->name,
1409 1410
					symbol->module->name,
					export_str(symbol->export));
L
Linus Torvalds 已提交
1411 1412 1413 1414 1415 1416
			symbol = symbol->next;
		}
	}
	write_if_changed(&buf, fname);
}

1417
int main(int argc, char **argv)
L
Linus Torvalds 已提交
1418 1419 1420 1421
{
	struct module *mod;
	struct buffer buf = { };
	char fname[SZ];
1422 1423
	char *kernel_read = NULL, *module_read = NULL;
	char *dump_write = NULL;
L
Linus Torvalds 已提交
1424
	int opt;
1425
	int err;
L
Linus Torvalds 已提交
1426

1427
	while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
L
Linus Torvalds 已提交
1428 1429
		switch(opt) {
			case 'i':
1430 1431 1432 1433 1434
				kernel_read = optarg;
				break;
			case 'I':
				module_read = optarg;
				external_module = 1;
L
Linus Torvalds 已提交
1435 1436 1437 1438 1439 1440 1441 1442 1443 1444
				break;
			case 'm':
				modversions = 1;
				break;
			case 'o':
				dump_write = optarg;
				break;
			case 'a':
				all_versions = 1;
				break;
1445 1446 1447
			case 'w':
				warn_unresolved = 1;
				break;
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452
			default:
				exit(1);
		}
	}

1453 1454 1455 1456
	if (kernel_read)
		read_dump(kernel_read, 1);
	if (module_read)
		read_dump(module_read, 0);
L
Linus Torvalds 已提交
1457 1458 1459 1460 1461

	while (optind < argc) {
		read_symbols(argv[optind++]);
	}

1462 1463 1464
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;
1465
		check_exports(mod);
1466 1467
	}

1468 1469
	err = 0;

L
Linus Torvalds 已提交
1470 1471 1472 1473 1474 1475 1476
	for (mod = modules; mod; mod = mod->next) {
		if (mod->skip)
			continue;

		buf.pos = 0;

		add_header(&buf, mod);
1477
		err |= add_versions(&buf, mod);
L
Linus Torvalds 已提交
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488
		add_depends(&buf, mod, modules);
		add_moddevtable(&buf, mod);
		add_srcversion(&buf, mod);

		sprintf(fname, "%s.mod.c", mod->name);
		write_if_changed(&buf, fname);
	}

	if (dump_write)
		write_dump(dump_write);

1489
	return err;
L
Linus Torvalds 已提交
1490
}