xref: /openbmc/linux/scripts/mod/modpost.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /* Postprocess module symbol versions
2  *
3  * Copyright 2003       Kai Germaschewski
4  * Copyright 2002-2004  Rusty Russell, IBM Corporation
5  * Copyright 2006       Sam Ravnborg
6  * Based in part on module-init-tools/depmod.c,file2alias
7  *
8  * This software may be used and distributed according to the terms
9  * of the GNU General Public License, incorporated herein by reference.
10  *
11  * Usage: modpost vmlinux module1.o module2.o ...
12  */
13 
14 #include <ctype.h>
15 #include "modpost.h"
16 #include "../../include/linux/license.h"
17 
18 /* Are we using CONFIG_MODVERSIONS? */
19 int modversions = 0;
20 /* Warn about undefined symbols? (do so if we have vmlinux) */
21 int have_vmlinux = 0;
22 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
23 static int all_versions = 0;
24 /* If we are modposting external module set to 1 */
25 static int external_module = 0;
26 /* Only warn about unresolved symbols */
27 static int warn_unresolved = 0;
28 /* How a symbol is exported */
29 enum export {
30 	export_plain,      export_unused,     export_gpl,
31 	export_unused_gpl, export_gpl_future, export_unknown
32 };
33 
34 void fatal(const char *fmt, ...)
35 {
36 	va_list arglist;
37 
38 	fprintf(stderr, "FATAL: ");
39 
40 	va_start(arglist, fmt);
41 	vfprintf(stderr, fmt, arglist);
42 	va_end(arglist);
43 
44 	exit(1);
45 }
46 
47 void warn(const char *fmt, ...)
48 {
49 	va_list arglist;
50 
51 	fprintf(stderr, "WARNING: ");
52 
53 	va_start(arglist, fmt);
54 	vfprintf(stderr, fmt, arglist);
55 	va_end(arglist);
56 }
57 
58 void merror(const char *fmt, ...)
59 {
60 	va_list arglist;
61 
62 	fprintf(stderr, "ERROR: ");
63 
64 	va_start(arglist, fmt);
65 	vfprintf(stderr, fmt, arglist);
66 	va_end(arglist);
67 }
68 
69 static int is_vmlinux(const char *modname)
70 {
71 	const char *myname;
72 
73 	if ((myname = strrchr(modname, '/')))
74 		myname++;
75 	else
76 		myname = modname;
77 
78 	return strcmp(myname, "vmlinux") == 0;
79 }
80 
81 void *do_nofail(void *ptr, const char *expr)
82 {
83 	if (!ptr) {
84 		fatal("modpost: Memory allocation failure: %s.\n", expr);
85 	}
86 	return ptr;
87 }
88 
89 /* A list of all modules we processed */
90 
91 static struct module *modules;
92 
93 static struct module *find_module(char *modname)
94 {
95 	struct module *mod;
96 
97 	for (mod = modules; mod; mod = mod->next)
98 		if (strcmp(mod->name, modname) == 0)
99 			break;
100 	return mod;
101 }
102 
103 static struct module *new_module(char *modname)
104 {
105 	struct module *mod;
106 	char *p, *s;
107 
108 	mod = NOFAIL(malloc(sizeof(*mod)));
109 	memset(mod, 0, sizeof(*mod));
110 	p = NOFAIL(strdup(modname));
111 
112 	/* strip trailing .o */
113 	if ((s = strrchr(p, '.')) != NULL)
114 		if (strcmp(s, ".o") == 0)
115 			*s = '\0';
116 
117 	/* add to list */
118 	mod->name = p;
119 	mod->gpl_compatible = -1;
120 	mod->next = modules;
121 	modules = mod;
122 
123 	return mod;
124 }
125 
126 /* A hash of all exported symbols,
127  * struct symbol is also used for lists of unresolved symbols */
128 
129 #define SYMBOL_HASH_SIZE 1024
130 
131 struct symbol {
132 	struct symbol *next;
133 	struct module *module;
134 	unsigned int crc;
135 	int crc_valid;
136 	unsigned int weak:1;
137 	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
138 	unsigned int kernel:1;     /* 1 if symbol is from kernel
139 				    *  (only for external modules) **/
140 	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
141 	enum export  export;       /* Type of export */
142 	char name[0];
143 };
144 
145 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
146 
147 /* This is based on the hash agorithm from gdbm, via tdb */
148 static inline unsigned int tdb_hash(const char *name)
149 {
150 	unsigned value;	/* Used to compute the hash value.  */
151 	unsigned   i;	/* Used to cycle through random values. */
152 
153 	/* Set the initial value from the key size. */
154 	for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
155 		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
156 
157 	return (1103515243 * value + 12345);
158 }
159 
160 /**
161  * Allocate a new symbols for use in the hash of exported symbols or
162  * the list of unresolved symbols per module
163  **/
164 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
165 				   struct symbol *next)
166 {
167 	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
168 
169 	memset(s, 0, sizeof(*s));
170 	strcpy(s->name, name);
171 	s->weak = weak;
172 	s->next = next;
173 	return s;
174 }
175 
176 /* For the hash of exported symbols */
177 static struct symbol *new_symbol(const char *name, struct module *module,
178 				 enum export export)
179 {
180 	unsigned int hash;
181 	struct symbol *new;
182 
183 	hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
184 	new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
185 	new->module = module;
186 	new->export = export;
187 	return new;
188 }
189 
190 static struct symbol *find_symbol(const char *name)
191 {
192 	struct symbol *s;
193 
194 	/* For our purposes, .foo matches foo.  PPC64 needs this. */
195 	if (name[0] == '.')
196 		name++;
197 
198 	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
199 		if (strcmp(s->name, name) == 0)
200 			return s;
201 	}
202 	return NULL;
203 }
204 
205 static struct {
206 	const char *str;
207 	enum export export;
208 } export_list[] = {
209 	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
210 	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
211 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
212 	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
213 	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
214 	{ .str = "(unknown)",                .export = export_unknown },
215 };
216 
217 
218 static const char *export_str(enum export ex)
219 {
220 	return export_list[ex].str;
221 }
222 
223 static enum export export_no(const char * s)
224 {
225 	int i;
226 	if (!s)
227 		return export_unknown;
228 	for (i = 0; export_list[i].export != export_unknown; i++) {
229 		if (strcmp(export_list[i].str, s) == 0)
230 			return export_list[i].export;
231 	}
232 	return export_unknown;
233 }
234 
235 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
236 {
237 	if (sec == elf->export_sec)
238 		return export_plain;
239 	else if (sec == elf->export_unused_sec)
240 		return export_unused;
241 	else if (sec == elf->export_gpl_sec)
242 		return export_gpl;
243 	else if (sec == elf->export_unused_gpl_sec)
244 		return export_unused_gpl;
245 	else if (sec == elf->export_gpl_future_sec)
246 		return export_gpl_future;
247 	else
248 		return export_unknown;
249 }
250 
251 /**
252  * Add an exported symbol - it may have already been added without a
253  * CRC, in this case just update the CRC
254  **/
255 static struct symbol *sym_add_exported(const char *name, struct module *mod,
256 				       enum export export)
257 {
258 	struct symbol *s = find_symbol(name);
259 
260 	if (!s) {
261 		s = new_symbol(name, mod, export);
262 	} else {
263 		if (!s->preloaded) {
264 			warn("%s: '%s' exported twice. Previous export "
265 			     "was in %s%s\n", mod->name, name,
266 			     s->module->name,
267 			     is_vmlinux(s->module->name) ?"":".ko");
268 		}
269 	}
270 	s->preloaded = 0;
271 	s->vmlinux   = is_vmlinux(mod->name);
272 	s->kernel    = 0;
273 	s->export    = export;
274 	return s;
275 }
276 
277 static void sym_update_crc(const char *name, struct module *mod,
278 			   unsigned int crc, enum export export)
279 {
280 	struct symbol *s = find_symbol(name);
281 
282 	if (!s)
283 		s = new_symbol(name, mod, export);
284 	s->crc = crc;
285 	s->crc_valid = 1;
286 }
287 
288 void *grab_file(const char *filename, unsigned long *size)
289 {
290 	struct stat st;
291 	void *map;
292 	int fd;
293 
294 	fd = open(filename, O_RDONLY);
295 	if (fd < 0 || fstat(fd, &st) != 0)
296 		return NULL;
297 
298 	*size = st.st_size;
299 	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
300 	close(fd);
301 
302 	if (map == MAP_FAILED)
303 		return NULL;
304 	return map;
305 }
306 
307 /**
308   * Return a copy of the next line in a mmap'ed file.
309   * spaces in the beginning of the line is trimmed away.
310   * Return a pointer to a static buffer.
311   **/
312 char* get_next_line(unsigned long *pos, void *file, unsigned long size)
313 {
314 	static char line[4096];
315 	int skip = 1;
316 	size_t len = 0;
317 	signed char *p = (signed char *)file + *pos;
318 	char *s = line;
319 
320 	for (; *pos < size ; (*pos)++)
321 	{
322 		if (skip && isspace(*p)) {
323 			p++;
324 			continue;
325 		}
326 		skip = 0;
327 		if (*p != '\n' && (*pos < size)) {
328 			len++;
329 			*s++ = *p++;
330 			if (len > 4095)
331 				break; /* Too long, stop */
332 		} else {
333 			/* End of string */
334 			*s = '\0';
335 			return line;
336 		}
337 	}
338 	/* End of buffer */
339 	return NULL;
340 }
341 
342 void release_file(void *file, unsigned long size)
343 {
344 	munmap(file, size);
345 }
346 
347 static int parse_elf(struct elf_info *info, const char *filename)
348 {
349 	unsigned int i;
350 	Elf_Ehdr *hdr;
351 	Elf_Shdr *sechdrs;
352 	Elf_Sym  *sym;
353 
354 	hdr = grab_file(filename, &info->size);
355 	if (!hdr) {
356 		perror(filename);
357 		exit(1);
358 	}
359 	info->hdr = hdr;
360 	if (info->size < sizeof(*hdr)) {
361 		/* file too small, assume this is an empty .o file */
362 		return 0;
363 	}
364 	/* Is this a valid ELF file? */
365 	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
366 	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
367 	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
368 	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
369 		/* Not an ELF file - silently ignore it */
370 		return 0;
371 	}
372 	/* Fix endianness in ELF header */
373 	hdr->e_shoff    = TO_NATIVE(hdr->e_shoff);
374 	hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
375 	hdr->e_shnum    = TO_NATIVE(hdr->e_shnum);
376 	hdr->e_machine  = TO_NATIVE(hdr->e_machine);
377 	sechdrs = (void *)hdr + hdr->e_shoff;
378 	info->sechdrs = sechdrs;
379 
380 	/* Fix endianness in section headers */
381 	for (i = 0; i < hdr->e_shnum; i++) {
382 		sechdrs[i].sh_type   = TO_NATIVE(sechdrs[i].sh_type);
383 		sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
384 		sechdrs[i].sh_size   = TO_NATIVE(sechdrs[i].sh_size);
385 		sechdrs[i].sh_link   = TO_NATIVE(sechdrs[i].sh_link);
386 		sechdrs[i].sh_name   = TO_NATIVE(sechdrs[i].sh_name);
387 	}
388 	/* Find symbol table. */
389 	for (i = 1; i < hdr->e_shnum; i++) {
390 		const char *secstrings
391 			= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
392 		const char *secname;
393 
394 		if (sechdrs[i].sh_offset > info->size) {
395 			fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
396 			return 0;
397 		}
398 		secname = secstrings + sechdrs[i].sh_name;
399 		if (strcmp(secname, ".modinfo") == 0) {
400 			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
401 			info->modinfo_len = sechdrs[i].sh_size;
402 		} else if (strcmp(secname, "__ksymtab") == 0)
403 			info->export_sec = i;
404 		else if (strcmp(secname, "__ksymtab_unused") == 0)
405 			info->export_unused_sec = i;
406 		else if (strcmp(secname, "__ksymtab_gpl") == 0)
407 			info->export_gpl_sec = i;
408 		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
409 			info->export_unused_gpl_sec = i;
410 		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
411 			info->export_gpl_future_sec = i;
412 
413 		if (sechdrs[i].sh_type != SHT_SYMTAB)
414 			continue;
415 
416 		info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
417 		info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset
418 			                         + sechdrs[i].sh_size;
419 		info->strtab       = (void *)hdr +
420 			             sechdrs[sechdrs[i].sh_link].sh_offset;
421 	}
422 	if (!info->symtab_start) {
423 		fatal("%s has no symtab?\n", filename);
424 	}
425 	/* Fix endianness in symbols */
426 	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
427 		sym->st_shndx = TO_NATIVE(sym->st_shndx);
428 		sym->st_name  = TO_NATIVE(sym->st_name);
429 		sym->st_value = TO_NATIVE(sym->st_value);
430 		sym->st_size  = TO_NATIVE(sym->st_size);
431 	}
432 	return 1;
433 }
434 
435 static void parse_elf_finish(struct elf_info *info)
436 {
437 	release_file(info->hdr, info->size);
438 }
439 
440 #define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
441 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
442 
443 static void handle_modversions(struct module *mod, struct elf_info *info,
444 			       Elf_Sym *sym, const char *symname)
445 {
446 	unsigned int crc;
447 	enum export export = export_from_sec(info, sym->st_shndx);
448 
449 	switch (sym->st_shndx) {
450 	case SHN_COMMON:
451 		warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
452 		break;
453 	case SHN_ABS:
454 		/* CRC'd symbol */
455 		if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
456 			crc = (unsigned int) sym->st_value;
457 			sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
458 					export);
459 		}
460 		break;
461 	case SHN_UNDEF:
462 		/* undefined symbol */
463 		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
464 		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
465 			break;
466 		/* ignore global offset table */
467 		if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
468 			break;
469 		/* ignore __this_module, it will be resolved shortly */
470 		if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
471 			break;
472 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
473 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
474 /* add compatibility with older glibc */
475 #ifndef STT_SPARC_REGISTER
476 #define STT_SPARC_REGISTER STT_REGISTER
477 #endif
478 		if (info->hdr->e_machine == EM_SPARC ||
479 		    info->hdr->e_machine == EM_SPARCV9) {
480 			/* Ignore register directives. */
481 			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
482 				break;
483 			if (symname[0] == '.') {
484 				char *munged = strdup(symname);
485 				munged[0] = '_';
486 				munged[1] = toupper(munged[1]);
487 				symname = munged;
488 			}
489 		}
490 #endif
491 
492 		if (memcmp(symname, MODULE_SYMBOL_PREFIX,
493 			   strlen(MODULE_SYMBOL_PREFIX)) == 0)
494 			mod->unres = alloc_symbol(symname +
495 						  strlen(MODULE_SYMBOL_PREFIX),
496 						  ELF_ST_BIND(sym->st_info) == STB_WEAK,
497 						  mod->unres);
498 		break;
499 	default:
500 		/* All exported symbols */
501 		if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
502 			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
503 					export);
504 		}
505 		if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
506 			mod->has_init = 1;
507 		if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
508 			mod->has_cleanup = 1;
509 		break;
510 	}
511 }
512 
513 /**
514  * Parse tag=value strings from .modinfo section
515  **/
516 static char *next_string(char *string, unsigned long *secsize)
517 {
518 	/* Skip non-zero chars */
519 	while (string[0]) {
520 		string++;
521 		if ((*secsize)-- <= 1)
522 			return NULL;
523 	}
524 
525 	/* Skip any zero padding. */
526 	while (!string[0]) {
527 		string++;
528 		if ((*secsize)-- <= 1)
529 			return NULL;
530 	}
531 	return string;
532 }
533 
534 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
535 			      const char *tag, char *info)
536 {
537 	char *p;
538 	unsigned int taglen = strlen(tag);
539 	unsigned long size = modinfo_len;
540 
541 	if (info) {
542 		size -= info - (char *)modinfo;
543 		modinfo = next_string(info, &size);
544 	}
545 
546 	for (p = modinfo; p; p = next_string(p, &size)) {
547 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
548 			return p + taglen + 1;
549 	}
550 	return NULL;
551 }
552 
553 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
554 			 const char *tag)
555 
556 {
557 	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
558 }
559 
560 /**
561  * Test if string s ends in string sub
562  * return 0 if match
563  **/
564 static int strrcmp(const char *s, const char *sub)
565 {
566         int slen, sublen;
567 
568 	if (!s || !sub)
569 		return 1;
570 
571 	slen = strlen(s);
572         sublen = strlen(sub);
573 
574 	if ((slen == 0) || (sublen == 0))
575 		return 1;
576 
577         if (sublen > slen)
578                 return 1;
579 
580         return memcmp(s + slen - sublen, sub, sublen);
581 }
582 
583 /**
584  * Whitelist to allow certain references to pass with no warning.
585  * Pattern 1:
586  *   If a module parameter is declared __initdata and permissions=0
587  *   then this is legal despite the warning generated.
588  *   We cannot see value of permissions here, so just ignore
589  *   this pattern.
590  *   The pattern is identified by:
591  *   tosec   = .init.data
592  *   fromsec = .data*
593  *   atsym   =__param*
594  *
595  * Pattern 2:
596  *   Many drivers utilise a *driver container with references to
597  *   add, remove, probe functions etc.
598  *   These functions may often be marked __init and we do not want to
599  *   warn here.
600  *   the pattern is identified by:
601  *   tosec   = .init.text | .exit.text | .init.data
602  *   fromsec = .data
603  *   atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
604  *
605  * Pattern 3:
606  *   Whitelist all references from .pci_fixup* section to .init.text
607  *   This is part of the PCI init when built-in
608  *
609  * Pattern 4:
610  *   Whitelist all refereces from .text.head to .init.data
611  *   Whitelist all refereces from .text.head to .init.text
612  *
613  * Pattern 5:
614  *   Some symbols belong to init section but still it is ok to reference
615  *   these from non-init sections as these symbols don't have any memory
616  *   allocated for them and symbol address and value are same. So even
617  *   if init section is freed, its ok to reference those symbols.
618  *   For ex. symbols marking the init section boundaries.
619  *   This pattern is identified by
620  *   refsymname = __init_begin, _sinittext, _einittext
621  *
622  * Pattern 6:
623  *   During the early init phase we have references from .init.text to
624  *   .text we have an intended section mismatch - do not warn about it.
625  *   See kernel_init() in init/main.c
626  *   tosec   = .init.text
627  *   fromsec = .text
628  *   atsym = kernel_init
629  *
630  * Pattern 7:
631  *  Logos used in drivers/video/logo reside in __initdata but the
632  *  funtion that references them are EXPORT_SYMBOL() so cannot be
633  *  marker __init. So we whitelist them here.
634  *  The pattern is:
635  *  tosec      = .init.data
636  *  fromsec    = .text*
637  *  refsymname = logo_
638  *
639  * Pattern 8:
640  *  Symbols contained in .paravirtprobe may safely reference .init.text.
641  *  The pattern is:
642  *  tosec   = .init.text
643  *  fromsec  = .paravirtprobe
644  *
645  * Pattern 9:
646  *  Some of functions are common code between boot time and hotplug
647  *  time. The bootmem allocater is called only boot time in its
648  *  functions. So it's ok to reference.
649  *  tosec    = .init.text
650  *
651  * Pattern 10:
652  *  ia64 has machvec table for each platform. It is mixture of function
653  *  pointer of .init.text and .text.
654  *  fromsec  = .machvec
655  **/
656 static int secref_whitelist(const char *modname, const char *tosec,
657 			    const char *fromsec, const char *atsym,
658 			    const char *refsymname)
659 {
660 	int f1 = 1, f2 = 1;
661 	const char **s;
662 	const char *pat2sym[] = {
663 		"driver",
664 		"_template", /* scsi uses *_template a lot */
665 		"_sht",      /* scsi also used *_sht to some extent */
666 		"_ops",
667 		"_probe",
668 		"_probe_one",
669 		"_console",
670 		"apic_es7000",
671 		NULL
672 	};
673 
674 	const char *pat3refsym[] = {
675 		"__init_begin",
676 		"_sinittext",
677 		"_einittext",
678 		NULL
679 	};
680 
681 	const char *pat4sym[] = {
682 		"sparse_index_alloc",
683 		"zone_wait_table_init",
684 		NULL
685 	};
686 
687 	/* Check for pattern 1 */
688 	if (strcmp(tosec, ".init.data") != 0)
689 		f1 = 0;
690 	if (strncmp(fromsec, ".data", strlen(".data")) != 0)
691 		f1 = 0;
692 	if (strncmp(atsym, "__param", strlen("__param")) != 0)
693 		f1 = 0;
694 
695 	if (f1)
696 		return f1;
697 
698 	/* Check for pattern 2 */
699 	if ((strcmp(tosec, ".init.text") != 0) &&
700 	    (strcmp(tosec, ".exit.text") != 0) &&
701 	    (strcmp(tosec, ".init.data") != 0))
702 		f2 = 0;
703 	if (strcmp(fromsec, ".data") != 0)
704 		f2 = 0;
705 
706 	for (s = pat2sym; *s; s++)
707 		if (strrcmp(atsym, *s) == 0)
708 			f1 = 1;
709 	if (f1 && f2)
710 		return 1;
711 
712 	/* Check for pattern 3 */
713 	if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
714 	    (strcmp(tosec, ".init.text") == 0))
715 	return 1;
716 
717 	/* Check for pattern 4 */
718 	if ((strcmp(fromsec, ".text.head") == 0) &&
719 		((strcmp(tosec, ".init.data") == 0) ||
720 		(strcmp(tosec, ".init.text") == 0)))
721 	return 1;
722 
723 	/* Check for pattern 5 */
724 	for (s = pat3refsym; *s; s++)
725 		if (strcmp(refsymname, *s) == 0)
726 			return 1;
727 
728 	/* Check for pattern 6 */
729 	if ((strcmp(tosec, ".init.text") == 0) &&
730 	    (strcmp(fromsec, ".text") == 0) &&
731 	    (strcmp(refsymname, "kernel_init") == 0))
732 		return 1;
733 
734 	/* Check for pattern 7 */
735 	if ((strcmp(tosec, ".init.data") == 0) &&
736 	    (strncmp(fromsec, ".text", strlen(".text")) == 0) &&
737 	    (strncmp(refsymname, "logo_", strlen("logo_")) == 0))
738 		return 1;
739 
740 	/* Check for pattern 8 */
741 	if ((strcmp(tosec, ".init.text") == 0) &&
742 	    (strcmp(fromsec, ".paravirtprobe") == 0))
743 		return 1;
744 
745 	/* Check for pattern 9 */
746 	if ((strcmp(tosec, ".init.text") == 0) &&
747 	    (strcmp(fromsec, ".text") == 0))
748 		for (s = pat4sym; *s; s++)
749 			if (strcmp(atsym, *s) == 0)
750 				return 1;
751 
752 	/* Check for pattern 10 */
753 	if (strcmp(fromsec, ".machvec") == 0)
754 		return 1;
755 
756 	return 0;
757 }
758 
759 /**
760  * Find symbol based on relocation record info.
761  * In some cases the symbol supplied is a valid symbol so
762  * return refsym. If st_name != 0 we assume this is a valid symbol.
763  * In other cases the symbol needs to be looked up in the symbol table
764  * based on section and address.
765  *  **/
766 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
767 				Elf_Sym *relsym)
768 {
769 	Elf_Sym *sym;
770 
771 	if (relsym->st_name != 0)
772 		return relsym;
773 	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
774 		if (sym->st_shndx != relsym->st_shndx)
775 			continue;
776 		if (sym->st_value == addr)
777 			return sym;
778 	}
779 	return NULL;
780 }
781 
782 static inline int is_arm_mapping_symbol(const char *str)
783 {
784 	return str[0] == '$' && strchr("atd", str[1])
785 	       && (str[2] == '\0' || str[2] == '.');
786 }
787 
788 /*
789  * If there's no name there, ignore it; likewise, ignore it if it's
790  * one of the magic symbols emitted used by current ARM tools.
791  *
792  * Otherwise if find_symbols_between() returns those symbols, they'll
793  * fail the whitelist tests and cause lots of false alarms ... fixable
794  * only by merging __exit and __init sections into __text, bloating
795  * the kernel (which is especially evil on embedded platforms).
796  */
797 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
798 {
799 	const char *name = elf->strtab + sym->st_name;
800 
801 	if (!name || !strlen(name))
802 		return 0;
803 	return !is_arm_mapping_symbol(name);
804 }
805 
806 /*
807  * Find symbols before or equal addr and after addr - in the section sec.
808  * If we find two symbols with equal offset prefer one with a valid name.
809  * The ELF format may have a better way to detect what type of symbol
810  * it is, but this works for now.
811  **/
812 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
813 				 const char *sec,
814 			         Elf_Sym **before, Elf_Sym **after)
815 {
816 	Elf_Sym *sym;
817 	Elf_Ehdr *hdr = elf->hdr;
818 	Elf_Addr beforediff = ~0;
819 	Elf_Addr afterdiff = ~0;
820 	const char *secstrings = (void *)hdr +
821 				 elf->sechdrs[hdr->e_shstrndx].sh_offset;
822 
823 	*before = NULL;
824 	*after = NULL;
825 
826 	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
827 		const char *symsec;
828 
829 		if (sym->st_shndx >= SHN_LORESERVE)
830 			continue;
831 		symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
832 		if (strcmp(symsec, sec) != 0)
833 			continue;
834 		if (!is_valid_name(elf, sym))
835 			continue;
836 		if (sym->st_value <= addr) {
837 			if ((addr - sym->st_value) < beforediff) {
838 				beforediff = addr - sym->st_value;
839 				*before = sym;
840 			}
841 			else if ((addr - sym->st_value) == beforediff) {
842 				*before = sym;
843 			}
844 		}
845 		else
846 		{
847 			if ((sym->st_value - addr) < afterdiff) {
848 				afterdiff = sym->st_value - addr;
849 				*after = sym;
850 			}
851 			else if ((sym->st_value - addr) == afterdiff) {
852 				*after = sym;
853 			}
854 		}
855 	}
856 }
857 
858 /**
859  * Print a warning about a section mismatch.
860  * Try to find symbols near it so user can find it.
861  * Check whitelist before warning - it may be a false positive.
862  **/
863 static void warn_sec_mismatch(const char *modname, const char *fromsec,
864 			      struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
865 {
866 	const char *refsymname = "";
867 	Elf_Sym *before, *after;
868 	Elf_Sym *refsym;
869 	Elf_Ehdr *hdr = elf->hdr;
870 	Elf_Shdr *sechdrs = elf->sechdrs;
871 	const char *secstrings = (void *)hdr +
872 				 sechdrs[hdr->e_shstrndx].sh_offset;
873 	const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
874 
875 	find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
876 
877 	refsym = find_elf_symbol(elf, r.r_addend, sym);
878 	if (refsym && strlen(elf->strtab + refsym->st_name))
879 		refsymname = elf->strtab + refsym->st_name;
880 
881 	/* check whitelist - we may ignore it */
882 	if (before &&
883 	    secref_whitelist(modname, secname, fromsec,
884 			     elf->strtab + before->st_name, refsymname))
885 		return;
886 
887 	if (before && after) {
888 		warn("%s - Section mismatch: reference to %s:%s from %s "
889 		     "between '%s' (at offset 0x%llx) and '%s'\n",
890 		     modname, secname, refsymname, fromsec,
891 		     elf->strtab + before->st_name,
892 		     (long long)r.r_offset,
893 		     elf->strtab + after->st_name);
894 	} else if (before) {
895 		warn("%s - Section mismatch: reference to %s:%s from %s "
896 		     "after '%s' (at offset 0x%llx)\n",
897 		     modname, secname, refsymname, fromsec,
898 		     elf->strtab + before->st_name,
899 		     (long long)r.r_offset);
900 	} else if (after) {
901 		warn("%s - Section mismatch: reference to %s:%s from %s "
902 		     "before '%s' (at offset -0x%llx)\n",
903 		     modname, secname, refsymname, fromsec,
904 		     elf->strtab + after->st_name,
905 		     (long long)r.r_offset);
906 	} else {
907 		warn("%s - Section mismatch: reference to %s:%s from %s "
908 		     "(offset 0x%llx)\n",
909 		     modname, secname, fromsec, refsymname,
910 		     (long long)r.r_offset);
911 	}
912 }
913 
914 /**
915  * A module includes a number of sections that are discarded
916  * either when loaded or when used as built-in.
917  * For loaded modules all functions marked __init and all data
918  * marked __initdata will be discarded when the module has been intialized.
919  * Likewise for modules used built-in the sections marked __exit
920  * are discarded because __exit marked function are supposed to be called
921  * only when a moduel is unloaded which never happes for built-in modules.
922  * The check_sec_ref() function traverses all relocation records
923  * to find all references to a section that reference a section that will
924  * be discarded and warns about it.
925  **/
926 static void check_sec_ref(struct module *mod, const char *modname,
927 			  struct elf_info *elf,
928 			  int section(const char*),
929 			  int section_ref_ok(const char *))
930 {
931 	int i;
932 	Elf_Sym  *sym;
933 	Elf_Ehdr *hdr = elf->hdr;
934 	Elf_Shdr *sechdrs = elf->sechdrs;
935 	const char *secstrings = (void *)hdr +
936 				 sechdrs[hdr->e_shstrndx].sh_offset;
937 
938 	/* Walk through all sections */
939 	for (i = 0; i < hdr->e_shnum; i++) {
940 		const char *name = secstrings + sechdrs[i].sh_name;
941 		const char *secname;
942 		Elf_Rela r;
943 		unsigned int r_sym;
944 		/* We want to process only relocation sections and not .init */
945 		if (sechdrs[i].sh_type == SHT_RELA) {
946 			Elf_Rela *rela;
947 			Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
948 			Elf_Rela *stop  = (void*)start + sechdrs[i].sh_size;
949 			name += strlen(".rela");
950 			if (section_ref_ok(name))
951 				continue;
952 
953 			for (rela = start; rela < stop; rela++) {
954 				r.r_offset = TO_NATIVE(rela->r_offset);
955 #if KERNEL_ELFCLASS == ELFCLASS64
956 				if (hdr->e_machine == EM_MIPS) {
957 					r_sym = ELF64_MIPS_R_SYM(rela->r_info);
958 					r_sym = TO_NATIVE(r_sym);
959 				} else {
960 					r.r_info = TO_NATIVE(rela->r_info);
961 					r_sym = ELF_R_SYM(r.r_info);
962 				}
963 #else
964 				r.r_info = TO_NATIVE(rela->r_info);
965 				r_sym = ELF_R_SYM(r.r_info);
966 #endif
967 				r.r_addend = TO_NATIVE(rela->r_addend);
968 				sym = elf->symtab_start + r_sym;
969 				/* Skip special sections */
970 				if (sym->st_shndx >= SHN_LORESERVE)
971 					continue;
972 
973 				secname = secstrings +
974 					sechdrs[sym->st_shndx].sh_name;
975 				if (section(secname))
976 					warn_sec_mismatch(modname, name,
977 							  elf, sym, r);
978 			}
979 		} else if (sechdrs[i].sh_type == SHT_REL) {
980 			Elf_Rel *rel;
981 			Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
982 			Elf_Rel *stop  = (void*)start + sechdrs[i].sh_size;
983 			name += strlen(".rel");
984 			if (section_ref_ok(name))
985 				continue;
986 
987 			for (rel = start; rel < stop; rel++) {
988 				r.r_offset = TO_NATIVE(rel->r_offset);
989 #if KERNEL_ELFCLASS == ELFCLASS64
990 				if (hdr->e_machine == EM_MIPS) {
991 					r_sym = ELF64_MIPS_R_SYM(rel->r_info);
992 					r_sym = TO_NATIVE(r_sym);
993 				} else {
994 					r.r_info = TO_NATIVE(rel->r_info);
995 					r_sym = ELF_R_SYM(r.r_info);
996 				}
997 #else
998 				r.r_info = TO_NATIVE(rel->r_info);
999 				r_sym = ELF_R_SYM(r.r_info);
1000 #endif
1001 				r.r_addend = 0;
1002 				sym = elf->symtab_start + r_sym;
1003 				/* Skip special sections */
1004 				if (sym->st_shndx >= SHN_LORESERVE)
1005 					continue;
1006 
1007 				secname = secstrings +
1008 					sechdrs[sym->st_shndx].sh_name;
1009 				if (section(secname))
1010 					warn_sec_mismatch(modname, name,
1011 							  elf, sym, r);
1012 			}
1013 		}
1014 	}
1015 }
1016 
1017 /**
1018  * Functions used only during module init is marked __init and is stored in
1019  * a .init.text section. Likewise data is marked __initdata and stored in
1020  * a .init.data section.
1021  * If this section is one of these sections return 1
1022  * See include/linux/init.h for the details
1023  **/
1024 static int init_section(const char *name)
1025 {
1026 	if (strcmp(name, ".init") == 0)
1027 		return 1;
1028 	if (strncmp(name, ".init.", strlen(".init.")) == 0)
1029 		return 1;
1030 	return 0;
1031 }
1032 
1033 /**
1034  * Identify sections from which references to a .init section is OK.
1035  *
1036  * Unfortunately references to read only data that referenced .init
1037  * sections had to be excluded. Almost all of these are false
1038  * positives, they are created by gcc. The downside of excluding rodata
1039  * is that there really are some user references from rodata to
1040  * init code, e.g. drivers/video/vgacon.c:
1041  *
1042  * const struct consw vga_con = {
1043  *        con_startup:            vgacon_startup,
1044  *
1045  * where vgacon_startup is __init.  If you want to wade through the false
1046  * positives, take out the check for rodata.
1047  **/
1048 static int init_section_ref_ok(const char *name)
1049 {
1050 	const char **s;
1051 	/* Absolute section names */
1052 	const char *namelist1[] = {
1053 		".init",
1054 		".opd",   /* see comment [OPD] at exit_section_ref_ok() */
1055 		".toc1",  /* used by ppc64 */
1056 		".stab",
1057 		".data.rel.ro", /* used by parisc64 */
1058 		".parainstructions",
1059 		".text.lock",
1060 		"__bug_table", /* used by powerpc for BUG() */
1061 		".pci_fixup_header",
1062 		".pci_fixup_final",
1063 		".pdr",
1064 		"__param",
1065 		"__ex_table",
1066 		".fixup",
1067 		".smp_locks",
1068 		".plt",  /* seen on ARCH=um build on x86_64. Harmless */
1069 		"__ftr_fixup",		/* powerpc cpu feature fixup */
1070 		"__fw_ftr_fixup",	/* powerpc firmware feature fixup */
1071 		NULL
1072 	};
1073 	/* Start of section names */
1074 	const char *namelist2[] = {
1075 		".init.",
1076 		".altinstructions",
1077 		".eh_frame",
1078 		".debug",
1079 		".parainstructions",
1080 		".rodata",
1081 		NULL
1082 	};
1083 	/* part of section name */
1084 	const char *namelist3 [] = {
1085 		".unwind",  /* sample: IA_64.unwind.init.text */
1086 		NULL
1087 	};
1088 
1089 	for (s = namelist1; *s; s++)
1090 		if (strcmp(*s, name) == 0)
1091 			return 1;
1092 	for (s = namelist2; *s; s++)
1093 		if (strncmp(*s, name, strlen(*s)) == 0)
1094 			return 1;
1095 	for (s = namelist3; *s; s++)
1096 		if (strstr(name, *s) != NULL)
1097 			return 1;
1098 	if (strrcmp(name, ".init") == 0)
1099 		return 1;
1100 	return 0;
1101 }
1102 
1103 /*
1104  * Functions used only during module exit is marked __exit and is stored in
1105  * a .exit.text section. Likewise data is marked __exitdata and stored in
1106  * a .exit.data section.
1107  * If this section is one of these sections return 1
1108  * See include/linux/init.h for the details
1109  **/
1110 static int exit_section(const char *name)
1111 {
1112 	if (strcmp(name, ".exit.text") == 0)
1113 		return 1;
1114 	if (strcmp(name, ".exit.data") == 0)
1115 		return 1;
1116 	return 0;
1117 
1118 }
1119 
1120 /*
1121  * Identify sections from which references to a .exit section is OK.
1122  *
1123  * [OPD] Keith Ownes <kaos@sgi.com> commented:
1124  * For our future {in}sanity, add a comment that this is the ppc .opd
1125  * section, not the ia64 .opd section.
1126  * ia64 .opd should not point to discarded sections.
1127  * [.rodata] like for .init.text we ignore .rodata references -same reason
1128  **/
1129 static int exit_section_ref_ok(const char *name)
1130 {
1131 	const char **s;
1132 	/* Absolute section names */
1133 	const char *namelist1[] = {
1134 		".exit.text",
1135 		".exit.data",
1136 		".init.text",
1137 		".rodata",
1138 		".opd", /* See comment [OPD] */
1139 		".toc1",  /* used by ppc64 */
1140 		".altinstructions",
1141 		".pdr",
1142 		"__bug_table", /* used by powerpc for BUG() */
1143 		".exitcall.exit",
1144 		".eh_frame",
1145 		".parainstructions",
1146 		".stab",
1147 		"__ex_table",
1148 		".fixup",
1149 		".smp_locks",
1150 		".plt",  /* seen on ARCH=um build on x86_64. Harmless */
1151 		NULL
1152 	};
1153 	/* Start of section names */
1154 	const char *namelist2[] = {
1155 		".debug",
1156 		NULL
1157 	};
1158 	/* part of section name */
1159 	const char *namelist3 [] = {
1160 		".unwind",  /* Sample: IA_64.unwind.exit.text */
1161 		NULL
1162 	};
1163 
1164 	for (s = namelist1; *s; s++)
1165 		if (strcmp(*s, name) == 0)
1166 			return 1;
1167 	for (s = namelist2; *s; s++)
1168 		if (strncmp(*s, name, strlen(*s)) == 0)
1169 			return 1;
1170 	for (s = namelist3; *s; s++)
1171 		if (strstr(name, *s) != NULL)
1172 			return 1;
1173 	return 0;
1174 }
1175 
1176 static void read_symbols(char *modname)
1177 {
1178 	const char *symname;
1179 	char *version;
1180 	char *license;
1181 	struct module *mod;
1182 	struct elf_info info = { };
1183 	Elf_Sym *sym;
1184 
1185 	if (!parse_elf(&info, modname))
1186 		return;
1187 
1188 	mod = new_module(modname);
1189 
1190 	/* When there's no vmlinux, don't print warnings about
1191 	 * unresolved symbols (since there'll be too many ;) */
1192 	if (is_vmlinux(modname)) {
1193 		have_vmlinux = 1;
1194 		mod->skip = 1;
1195 	}
1196 
1197 	license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1198 	while (license) {
1199 		if (license_is_gpl_compatible(license))
1200 			mod->gpl_compatible = 1;
1201 		else {
1202 			mod->gpl_compatible = 0;
1203 			break;
1204 		}
1205 		license = get_next_modinfo(info.modinfo, info.modinfo_len,
1206 					   "license", license);
1207 	}
1208 
1209 	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1210 		symname = info.strtab + sym->st_name;
1211 
1212 		handle_modversions(mod, &info, sym, symname);
1213 		handle_moddevtable(mod, &info, sym, symname);
1214 	}
1215 	check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1216 	check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1217 
1218 	version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1219 	if (version)
1220 		maybe_frob_rcs_version(modname, version, info.modinfo,
1221 				       version - (char *)info.hdr);
1222 	if (version || (all_versions && !is_vmlinux(modname)))
1223 		get_src_version(modname, mod->srcversion,
1224 				sizeof(mod->srcversion)-1);
1225 
1226 	parse_elf_finish(&info);
1227 
1228 	/* Our trick to get versioning for struct_module - it's
1229 	 * never passed as an argument to an exported function, so
1230 	 * the automatic versioning doesn't pick it up, but it's really
1231 	 * important anyhow */
1232 	if (modversions)
1233 		mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1234 }
1235 
1236 #define SZ 500
1237 
1238 /* We first write the generated file into memory using the
1239  * following helper, then compare to the file on disk and
1240  * only update the later if anything changed */
1241 
1242 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1243 						      const char *fmt, ...)
1244 {
1245 	char tmp[SZ];
1246 	int len;
1247 	va_list ap;
1248 
1249 	va_start(ap, fmt);
1250 	len = vsnprintf(tmp, SZ, fmt, ap);
1251 	buf_write(buf, tmp, len);
1252 	va_end(ap);
1253 }
1254 
1255 void buf_write(struct buffer *buf, const char *s, int len)
1256 {
1257 	if (buf->size - buf->pos < len) {
1258 		buf->size += len + SZ;
1259 		buf->p = realloc(buf->p, buf->size);
1260 	}
1261 	strncpy(buf->p + buf->pos, s, len);
1262 	buf->pos += len;
1263 }
1264 
1265 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1266 {
1267 	const char *e = is_vmlinux(m) ?"":".ko";
1268 
1269 	switch (exp) {
1270 	case export_gpl:
1271 		fatal("modpost: GPL-incompatible module %s%s "
1272 		      "uses GPL-only symbol '%s'\n", m, e, s);
1273 		break;
1274 	case export_unused_gpl:
1275 		fatal("modpost: GPL-incompatible module %s%s "
1276 		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1277 		break;
1278 	case export_gpl_future:
1279 		warn("modpost: GPL-incompatible module %s%s "
1280 		      "uses future GPL-only symbol '%s'\n", m, e, s);
1281 		break;
1282 	case export_plain:
1283 	case export_unused:
1284 	case export_unknown:
1285 		/* ignore */
1286 		break;
1287 	}
1288 }
1289 
1290 static void check_for_unused(enum export exp, const char* m, const char* s)
1291 {
1292 	const char *e = is_vmlinux(m) ?"":".ko";
1293 
1294 	switch (exp) {
1295 	case export_unused:
1296 	case export_unused_gpl:
1297 		warn("modpost: module %s%s "
1298 		      "uses symbol '%s' marked UNUSED\n", m, e, s);
1299 		break;
1300 	default:
1301 		/* ignore */
1302 		break;
1303 	}
1304 }
1305 
1306 static void check_exports(struct module *mod)
1307 {
1308 	struct symbol *s, *exp;
1309 
1310 	for (s = mod->unres; s; s = s->next) {
1311 		const char *basename;
1312 		exp = find_symbol(s->name);
1313 		if (!exp || exp->module == mod)
1314 			continue;
1315 		basename = strrchr(mod->name, '/');
1316 		if (basename)
1317 			basename++;
1318 		else
1319 			basename = mod->name;
1320 		if (!mod->gpl_compatible)
1321 			check_for_gpl_usage(exp->export, basename, exp->name);
1322 		check_for_unused(exp->export, basename, exp->name);
1323         }
1324 }
1325 
1326 /**
1327  * Header for the generated file
1328  **/
1329 static void add_header(struct buffer *b, struct module *mod)
1330 {
1331 	buf_printf(b, "#include <linux/module.h>\n");
1332 	buf_printf(b, "#include <linux/vermagic.h>\n");
1333 	buf_printf(b, "#include <linux/compiler.h>\n");
1334 	buf_printf(b, "\n");
1335 	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1336 	buf_printf(b, "\n");
1337 	buf_printf(b, "struct module __this_module\n");
1338 	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1339 	buf_printf(b, " .name = KBUILD_MODNAME,\n");
1340 	if (mod->has_init)
1341 		buf_printf(b, " .init = init_module,\n");
1342 	if (mod->has_cleanup)
1343 		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1344 			      " .exit = cleanup_module,\n"
1345 			      "#endif\n");
1346 	buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1347 	buf_printf(b, "};\n");
1348 }
1349 
1350 /**
1351  * Record CRCs for unresolved symbols
1352  **/
1353 static int add_versions(struct buffer *b, struct module *mod)
1354 {
1355 	struct symbol *s, *exp;
1356 	int err = 0;
1357 
1358 	for (s = mod->unres; s; s = s->next) {
1359 		exp = find_symbol(s->name);
1360 		if (!exp || exp->module == mod) {
1361 			if (have_vmlinux && !s->weak) {
1362 				if (warn_unresolved) {
1363 					warn("\"%s\" [%s.ko] undefined!\n",
1364 					     s->name, mod->name);
1365 				} else {
1366 					merror("\"%s\" [%s.ko] undefined!\n",
1367 					          s->name, mod->name);
1368 					err = 1;
1369 				}
1370 			}
1371 			continue;
1372 		}
1373 		s->module = exp->module;
1374 		s->crc_valid = exp->crc_valid;
1375 		s->crc = exp->crc;
1376 	}
1377 
1378 	if (!modversions)
1379 		return err;
1380 
1381 	buf_printf(b, "\n");
1382 	buf_printf(b, "static const struct modversion_info ____versions[]\n");
1383 	buf_printf(b, "__attribute_used__\n");
1384 	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1385 
1386 	for (s = mod->unres; s; s = s->next) {
1387 		if (!s->module) {
1388 			continue;
1389 		}
1390 		if (!s->crc_valid) {
1391 			warn("\"%s\" [%s.ko] has no CRC!\n",
1392 				s->name, mod->name);
1393 			continue;
1394 		}
1395 		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1396 	}
1397 
1398 	buf_printf(b, "};\n");
1399 
1400 	return err;
1401 }
1402 
1403 static void add_depends(struct buffer *b, struct module *mod,
1404 			struct module *modules)
1405 {
1406 	struct symbol *s;
1407 	struct module *m;
1408 	int first = 1;
1409 
1410 	for (m = modules; m; m = m->next) {
1411 		m->seen = is_vmlinux(m->name);
1412 	}
1413 
1414 	buf_printf(b, "\n");
1415 	buf_printf(b, "static const char __module_depends[]\n");
1416 	buf_printf(b, "__attribute_used__\n");
1417 	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1418 	buf_printf(b, "\"depends=");
1419 	for (s = mod->unres; s; s = s->next) {
1420 		const char *p;
1421 		if (!s->module)
1422 			continue;
1423 
1424 		if (s->module->seen)
1425 			continue;
1426 
1427 		s->module->seen = 1;
1428 		if ((p = strrchr(s->module->name, '/')) != NULL)
1429 			p++;
1430 		else
1431 			p = s->module->name;
1432 		buf_printf(b, "%s%s", first ? "" : ",", p);
1433 		first = 0;
1434 	}
1435 	buf_printf(b, "\";\n");
1436 }
1437 
1438 static void add_srcversion(struct buffer *b, struct module *mod)
1439 {
1440 	if (mod->srcversion[0]) {
1441 		buf_printf(b, "\n");
1442 		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1443 			   mod->srcversion);
1444 	}
1445 }
1446 
1447 static void write_if_changed(struct buffer *b, const char *fname)
1448 {
1449 	char *tmp;
1450 	FILE *file;
1451 	struct stat st;
1452 
1453 	file = fopen(fname, "r");
1454 	if (!file)
1455 		goto write;
1456 
1457 	if (fstat(fileno(file), &st) < 0)
1458 		goto close_write;
1459 
1460 	if (st.st_size != b->pos)
1461 		goto close_write;
1462 
1463 	tmp = NOFAIL(malloc(b->pos));
1464 	if (fread(tmp, 1, b->pos, file) != b->pos)
1465 		goto free_write;
1466 
1467 	if (memcmp(tmp, b->p, b->pos) != 0)
1468 		goto free_write;
1469 
1470 	free(tmp);
1471 	fclose(file);
1472 	return;
1473 
1474  free_write:
1475 	free(tmp);
1476  close_write:
1477 	fclose(file);
1478  write:
1479 	file = fopen(fname, "w");
1480 	if (!file) {
1481 		perror(fname);
1482 		exit(1);
1483 	}
1484 	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1485 		perror(fname);
1486 		exit(1);
1487 	}
1488 	fclose(file);
1489 }
1490 
1491 /* parse Module.symvers file. line format:
1492  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1493  **/
1494 static void read_dump(const char *fname, unsigned int kernel)
1495 {
1496 	unsigned long size, pos = 0;
1497 	void *file = grab_file(fname, &size);
1498 	char *line;
1499 
1500         if (!file)
1501 		/* No symbol versions, silently ignore */
1502 		return;
1503 
1504 	while ((line = get_next_line(&pos, file, size))) {
1505 		char *symname, *modname, *d, *export, *end;
1506 		unsigned int crc;
1507 		struct module *mod;
1508 		struct symbol *s;
1509 
1510 		if (!(symname = strchr(line, '\t')))
1511 			goto fail;
1512 		*symname++ = '\0';
1513 		if (!(modname = strchr(symname, '\t')))
1514 			goto fail;
1515 		*modname++ = '\0';
1516 		if ((export = strchr(modname, '\t')) != NULL)
1517 			*export++ = '\0';
1518 		if (export && ((end = strchr(export, '\t')) != NULL))
1519 			*end = '\0';
1520 		crc = strtoul(line, &d, 16);
1521 		if (*symname == '\0' || *modname == '\0' || *d != '\0')
1522 			goto fail;
1523 
1524 		if (!(mod = find_module(modname))) {
1525 			if (is_vmlinux(modname)) {
1526 				have_vmlinux = 1;
1527 			}
1528 			mod = new_module(NOFAIL(strdup(modname)));
1529 			mod->skip = 1;
1530 		}
1531 		s = sym_add_exported(symname, mod, export_no(export));
1532 		s->kernel    = kernel;
1533 		s->preloaded = 1;
1534 		sym_update_crc(symname, mod, crc, export_no(export));
1535 	}
1536 	return;
1537 fail:
1538 	fatal("parse error in symbol dump file\n");
1539 }
1540 
1541 /* For normal builds always dump all symbols.
1542  * For external modules only dump symbols
1543  * that are not read from kernel Module.symvers.
1544  **/
1545 static int dump_sym(struct symbol *sym)
1546 {
1547 	if (!external_module)
1548 		return 1;
1549 	if (sym->vmlinux || sym->kernel)
1550 		return 0;
1551 	return 1;
1552 }
1553 
1554 static void write_dump(const char *fname)
1555 {
1556 	struct buffer buf = { };
1557 	struct symbol *symbol;
1558 	int n;
1559 
1560 	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1561 		symbol = symbolhash[n];
1562 		while (symbol) {
1563 			if (dump_sym(symbol))
1564 				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1565 					symbol->crc, symbol->name,
1566 					symbol->module->name,
1567 					export_str(symbol->export));
1568 			symbol = symbol->next;
1569 		}
1570 	}
1571 	write_if_changed(&buf, fname);
1572 }
1573 
1574 int main(int argc, char **argv)
1575 {
1576 	struct module *mod;
1577 	struct buffer buf = { };
1578 	char fname[SZ];
1579 	char *kernel_read = NULL, *module_read = NULL;
1580 	char *dump_write = NULL;
1581 	int opt;
1582 	int err;
1583 
1584 	while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
1585 		switch(opt) {
1586 			case 'i':
1587 				kernel_read = optarg;
1588 				break;
1589 			case 'I':
1590 				module_read = optarg;
1591 				external_module = 1;
1592 				break;
1593 			case 'm':
1594 				modversions = 1;
1595 				break;
1596 			case 'o':
1597 				dump_write = optarg;
1598 				break;
1599 			case 'a':
1600 				all_versions = 1;
1601 				break;
1602 			case 'w':
1603 				warn_unresolved = 1;
1604 				break;
1605 			default:
1606 				exit(1);
1607 		}
1608 	}
1609 
1610 	if (kernel_read)
1611 		read_dump(kernel_read, 1);
1612 	if (module_read)
1613 		read_dump(module_read, 0);
1614 
1615 	while (optind < argc) {
1616 		read_symbols(argv[optind++]);
1617 	}
1618 
1619 	for (mod = modules; mod; mod = mod->next) {
1620 		if (mod->skip)
1621 			continue;
1622 		check_exports(mod);
1623 	}
1624 
1625 	err = 0;
1626 
1627 	for (mod = modules; mod; mod = mod->next) {
1628 		if (mod->skip)
1629 			continue;
1630 
1631 		buf.pos = 0;
1632 
1633 		add_header(&buf, mod);
1634 		err |= add_versions(&buf, mod);
1635 		add_depends(&buf, mod, modules);
1636 		add_moddevtable(&buf, mod);
1637 		add_srcversion(&buf, mod);
1638 
1639 		sprintf(fname, "%s.mod.c", mod->name);
1640 		write_if_changed(&buf, fname);
1641 	}
1642 
1643 	if (dump_write)
1644 		write_dump(dump_write);
1645 
1646 	return err;
1647 }
1648