projects/linux·blob v2.6.16 · refs

802 lines · 17.3 KiB

1/* Postprocess module symbol versions
2 *
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 *
6 * Based in part on module-init-tools/depmod.c,file2alias
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * Usage: modpost vmlinux module1.o module2.o ...
12 */
13
14#include <ctype.h>
15#include "modpost.h"
16
17/* Are we using CONFIG_MODVERSIONS? */
18int modversions = 0;
19/* Warn about undefined symbols? (do so if we have vmlinux) */
20int have_vmlinux = 0;
21/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
22static int all_versions = 0;
23
24void
25fatal(const char *fmt, ...)
26{
27 va_list arglist;
28
29 fprintf(stderr, "FATAL: ");
30
31 va_start(arglist, fmt);
32 vfprintf(stderr, fmt, arglist);
33 va_end(arglist);
34
35 exit(1);
36}
37
38void
39warn(const char *fmt, ...)
40{
41 va_list arglist;
42
43 fprintf(stderr, "WARNING: ");
44
45 va_start(arglist, fmt);
46 vfprintf(stderr, fmt, arglist);
47 va_end(arglist);
48}
49
50void *do_nofail(void *ptr, const char *expr)
51{
52 if (!ptr) {
53 fatal("modpost: Memory allocation failure: %s.\n", expr);
54 }
55 return ptr;
56}
57
58/* A list of all modules we processed */
59
60static struct module *modules;
61
62struct module *
63find_module(char *modname)
64{
65 struct module *mod;
66
67 for (mod = modules; mod; mod = mod->next)
68 if (strcmp(mod->name, modname) == 0)
69 break;
70 return mod;
71}
72
73struct module *
74new_module(char *modname)
75{
76 struct module *mod;
77 char *p, *s;
78
79 mod = NOFAIL(malloc(sizeof(*mod)));
80 memset(mod, 0, sizeof(*mod));
81 p = NOFAIL(strdup(modname));
82
83 /* strip trailing .o */
84 if ((s = strrchr(p, '.')) != NULL)
85 if (strcmp(s, ".o") == 0)
86 *s = '\0';
87
88 /* add to list */
89 mod->name = p;
90 mod->next = modules;
91 modules = mod;
92
93 return mod;
94}
95
96/* A hash of all exported symbols,
97 * struct symbol is also used for lists of unresolved symbols */
98
99#define SYMBOL_HASH_SIZE 1024
100
101struct symbol {
102 struct symbol *next;
103 struct module *module;
104 unsigned int crc;
105 int crc_valid;
106 unsigned int weak:1;
107 char name[0];
108};
109
110static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
111
112/* This is based on the hash agorithm from gdbm, via tdb */
113static inline unsigned int tdb_hash(const char *name)
114{
115 unsigned value; /* Used to compute the hash value. */
116 unsigned i; /* Used to cycle through random values. */
117
118 /* Set the initial value from the key size. */
119 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
120 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
121
122 return (1103515243 * value + 12345);
123}
124
125/* Allocate a new symbols for use in the hash of exported symbols or
126 * the list of unresolved symbols per module */
127
128struct symbol *
129alloc_symbol(const char *name, unsigned int weak, struct symbol *next)
130{
131 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
132
133 memset(s, 0, sizeof(*s));
134 strcpy(s->name, name);
135 s->weak = weak;
136 s->next = next;
137 return s;
138}
139
140/* For the hash of exported symbols */
141
142void
143new_symbol(const char *name, struct module *module, unsigned int *crc)
144{
145 unsigned int hash;
146 struct symbol *new;
147
148 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
149 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
150 new->module = module;
151 if (crc) {
152 new->crc = *crc;
153 new->crc_valid = 1;
154 }
155}
156
157struct symbol *
158find_symbol(const char *name)
159{
160 struct symbol *s;
161
162 /* For our purposes, .foo matches foo. PPC64 needs this. */
163 if (name[0] == '.')
164 name++;
165
166 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
167 if (strcmp(s->name, name) == 0)
168 return s;
169 }
170 return NULL;
171}
172
173/* Add an exported symbol - it may have already been added without a
174 * CRC, in this case just update the CRC */
175void
176add_exported_symbol(const char *name, struct module *module, unsigned int *crc)
177{
178 struct symbol *s = find_symbol(name);
179
180 if (!s) {
181 new_symbol(name, module, crc);
182 return;
183 }
184 if (crc) {
185 s->crc = *crc;
186 s->crc_valid = 1;
187 }
188}
189
190void *
191grab_file(const char *filename, unsigned long *size)
192{
193 struct stat st;
194 void *map;
195 int fd;
196
197 fd = open(filename, O_RDONLY);
198 if (fd < 0 || fstat(fd, &st) != 0)
199 return NULL;
200
201 *size = st.st_size;
202 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
203 close(fd);
204
205 if (map == MAP_FAILED)
206 return NULL;
207 return map;
208}
209
210/*
211 Return a copy of the next line in a mmap'ed file.
212 spaces in the beginning of the line is trimmed away.
213 Return a pointer to a static buffer.
214*/
215char*
216get_next_line(unsigned long *pos, void *file, unsigned long size)
217{
218 static char line[4096];
219 int skip = 1;
220 size_t len = 0;
221 signed char *p = (signed char *)file + *pos;
222 char *s = line;
223
224 for (; *pos < size ; (*pos)++)
225 {
226 if (skip && isspace(*p)) {
227 p++;
228 continue;
229 }
230 skip = 0;
231 if (*p != '\n' && (*pos < size)) {
232 len++;
233 *s++ = *p++;
234 if (len > 4095)
235 break; /* Too long, stop */
236 } else {
237 /* End of string */
238 *s = '\0';
239 return line;
240 }
241 }
242 /* End of buffer */
243 return NULL;
244}
245
246void
247release_file(void *file, unsigned long size)
248{
249 munmap(file, size);
250}
251
252void
253parse_elf(struct elf_info *info, const char *filename)
254{
255 unsigned int i;
256 Elf_Ehdr *hdr = info->hdr;
257 Elf_Shdr *sechdrs;
258 Elf_Sym *sym;
259
260 hdr = grab_file(filename, &info->size);
261 if (!hdr) {
262 perror(filename);
263 abort();
264 }
265 info->hdr = hdr;
266 if (info->size < sizeof(*hdr))
267 goto truncated;
268
269 /* Fix endianness in ELF header */
270 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
271 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
272 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
273 hdr->e_machine = TO_NATIVE(hdr->e_machine);
274 sechdrs = (void *)hdr + hdr->e_shoff;
275 info->sechdrs = sechdrs;
276
277 /* Fix endianness in section headers */
278 for (i = 0; i < hdr->e_shnum; i++) {
279 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
280 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
281 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
282 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
283 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
284 }
285 /* Find symbol table. */
286 for (i = 1; i < hdr->e_shnum; i++) {
287 const char *secstrings
288 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
289
290 if (sechdrs[i].sh_offset > info->size)
291 goto truncated;
292 if (strcmp(secstrings+sechdrs[i].sh_name, ".modinfo") == 0) {
293 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
294 info->modinfo_len = sechdrs[i].sh_size;
295 }
296 if (sechdrs[i].sh_type != SHT_SYMTAB)
297 continue;
298
299 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
300 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
301 + sechdrs[i].sh_size;
302 info->strtab = (void *)hdr +
303 sechdrs[sechdrs[i].sh_link].sh_offset;
304 }
305 if (!info->symtab_start) {
306 fprintf(stderr, "modpost: %s no symtab?\n", filename);
307 abort();
308 }
309 /* Fix endianness in symbols */
310 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
311 sym->st_shndx = TO_NATIVE(sym->st_shndx);
312 sym->st_name = TO_NATIVE(sym->st_name);
313 sym->st_value = TO_NATIVE(sym->st_value);
314 sym->st_size = TO_NATIVE(sym->st_size);
315 }
316 return;
317
318 truncated:
319 fprintf(stderr, "modpost: %s is truncated.\n", filename);
320 abort();
321}
322
323void
324parse_elf_finish(struct elf_info *info)
325{
326 release_file(info->hdr, info->size);
327}
328
329#define CRC_PFX "__crc_"
330#define KSYMTAB_PFX "__ksymtab_"
331
332void
333handle_modversions(struct module *mod, struct elf_info *info,
334 Elf_Sym *sym, const char *symname)
335{
336 unsigned int crc;
337
338 switch (sym->st_shndx) {
339 case SHN_COMMON:
340 fprintf(stderr, "*** Warning: \"%s\" [%s] is COMMON symbol\n",
341 symname, mod->name);
342 break;
343 case SHN_ABS:
344 /* CRC'd symbol */
345 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
346 crc = (unsigned int) sym->st_value;
347 add_exported_symbol(symname + strlen(CRC_PFX),
348 mod, &crc);
349 }
350 break;
351 case SHN_UNDEF:
352 /* undefined symbol */
353 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
354 ELF_ST_BIND(sym->st_info) != STB_WEAK)
355 break;
356 /* ignore global offset table */
357 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
358 break;
359 /* ignore __this_module, it will be resolved shortly */
360 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
361 break;
362/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
363#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
364/* add compatibility with older glibc */
365#ifndef STT_SPARC_REGISTER
366#define STT_SPARC_REGISTER STT_REGISTER
367#endif
368 if (info->hdr->e_machine == EM_SPARC ||
369 info->hdr->e_machine == EM_SPARCV9) {
370 /* Ignore register directives. */
371 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
372 break;
373 if (symname[0] == '.') {
374 char *munged = strdup(symname);
375 munged[0] = '_';
376 munged[1] = toupper(munged[1]);
377 symname = munged;
378 }
379 }
380#endif
381
382 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
383 strlen(MODULE_SYMBOL_PREFIX)) == 0)
384 mod->unres = alloc_symbol(symname +
385 strlen(MODULE_SYMBOL_PREFIX),
386 ELF_ST_BIND(sym->st_info) == STB_WEAK,
387 mod->unres);
388 break;
389 default:
390 /* All exported symbols */
391 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
392 add_exported_symbol(symname + strlen(KSYMTAB_PFX),
393 mod, NULL);
394 }
395 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
396 mod->has_init = 1;
397 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
398 mod->has_cleanup = 1;
399 break;
400 }
401}
402
403int
404is_vmlinux(const char *modname)
405{
406 const char *myname;
407
408 if ((myname = strrchr(modname, '/')))
409 myname++;
410 else
411 myname = modname;
412
413 return strcmp(myname, "vmlinux") == 0;
414}
415
416/* Parse tag=value strings from .modinfo section */
417static char *next_string(char *string, unsigned long *secsize)
418{
419 /* Skip non-zero chars */
420 while (string[0]) {
421 string++;
422 if ((*secsize)-- <= 1)
423 return NULL;
424 }
425
426 /* Skip any zero padding. */
427 while (!string[0]) {
428 string++;
429 if ((*secsize)-- <= 1)
430 return NULL;
431 }
432 return string;
433}
434
435static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
436 const char *tag)
437{
438 char *p;
439 unsigned int taglen = strlen(tag);
440 unsigned long size = modinfo_len;
441
442 for (p = modinfo; p; p = next_string(p, &size)) {
443 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
444 return p + taglen + 1;
445 }
446 return NULL;
447}
448
449void
450read_symbols(char *modname)
451{
452 const char *symname;
453 char *version;
454 struct module *mod;
455 struct elf_info info = { };
456 Elf_Sym *sym;
457
458 parse_elf(&info, modname);
459
460 mod = new_module(modname);
461
462 /* When there's no vmlinux, don't print warnings about
463 * unresolved symbols (since there'll be too many ;) */
464 if (is_vmlinux(modname)) {
465 unsigned int fake_crc = 0;
466 have_vmlinux = 1;
467 add_exported_symbol("struct_module", mod, &fake_crc);
468 mod->skip = 1;
469 }
470
471 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
472 symname = info.strtab + sym->st_name;
473
474 handle_modversions(mod, &info, sym, symname);
475 handle_moddevtable(mod, &info, sym, symname);
476 }
477
478 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
479 if (version)
480 maybe_frob_rcs_version(modname, version, info.modinfo,
481 version - (char *)info.hdr);
482 if (version || (all_versions && !is_vmlinux(modname)))
483 get_src_version(modname, mod->srcversion,
484 sizeof(mod->srcversion)-1);
485
486 parse_elf_finish(&info);
487
488 /* Our trick to get versioning for struct_module - it's
489 * never passed as an argument to an exported function, so
490 * the automatic versioning doesn't pick it up, but it's really
491 * important anyhow */
492 if (modversions)
493 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
494}
495
496#define SZ 500
497
498/* We first write the generated file into memory using the
499 * following helper, then compare to the file on disk and
500 * only update the later if anything changed */
501
502void __attribute__((format(printf, 2, 3)))
503buf_printf(struct buffer *buf, const char *fmt, ...)
504{
505 char tmp[SZ];
506 int len;
507 va_list ap;
508
509 va_start(ap, fmt);
510 len = vsnprintf(tmp, SZ, fmt, ap);
511 buf_write(buf, tmp, len);
512 va_end(ap);
513}
514
515void
516buf_write(struct buffer *buf, const char *s, int len)
517{
518 if (buf->size - buf->pos < len) {
519 buf->size += len + SZ;
520 buf->p = realloc(buf->p, buf->size);
521 }
522 strncpy(buf->p + buf->pos, s, len);
523 buf->pos += len;
524}
525
526/* Header for the generated file */
527
528void
529add_header(struct buffer *b, struct module *mod)
530{
531 buf_printf(b, "#include <linux/module.h>\n");
532 buf_printf(b, "#include <linux/vermagic.h>\n");
533 buf_printf(b, "#include <linux/compiler.h>\n");
534 buf_printf(b, "\n");
535 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
536 buf_printf(b, "\n");
537 buf_printf(b, "struct module __this_module\n");
538 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
539 buf_printf(b, " .name = KBUILD_MODNAME,\n");
540 if (mod->has_init)
541 buf_printf(b, " .init = init_module,\n");
542 if (mod->has_cleanup)
543 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
544 " .exit = cleanup_module,\n"
545 "#endif\n");
546 buf_printf(b, "};\n");
547}
548
549/* Record CRCs for unresolved symbols */
550
551void
552add_versions(struct buffer *b, struct module *mod)
553{
554 struct symbol *s, *exp;
555
556 for (s = mod->unres; s; s = s->next) {
557 exp = find_symbol(s->name);
558 if (!exp || exp->module == mod) {
559 if (have_vmlinux && !s->weak)
560 fprintf(stderr, "*** Warning: \"%s\" [%s.ko] "
561 "undefined!\n", s->name, mod->name);
562 continue;
563 }
564 s->module = exp->module;
565 s->crc_valid = exp->crc_valid;
566 s->crc = exp->crc;
567 }
568
569 if (!modversions)
570 return;
571
572 buf_printf(b, "\n");
573 buf_printf(b, "static const struct modversion_info ____versions[]\n");
574 buf_printf(b, "__attribute_used__\n");
575 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
576
577 for (s = mod->unres; s; s = s->next) {
578 if (!s->module) {
579 continue;
580 }
581 if (!s->crc_valid) {
582 fprintf(stderr, "*** Warning: \"%s\" [%s.ko] "
583 "has no CRC!\n",
584 s->name, mod->name);
585 continue;
586 }
587 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
588 }
589
590 buf_printf(b, "};\n");
591}
592
593void
594add_depends(struct buffer *b, struct module *mod, struct module *modules)
595{
596 struct symbol *s;
597 struct module *m;
598 int first = 1;
599
600 for (m = modules; m; m = m->next) {
601 m->seen = is_vmlinux(m->name);
602 }
603
604 buf_printf(b, "\n");
605 buf_printf(b, "static const char __module_depends[]\n");
606 buf_printf(b, "__attribute_used__\n");
607 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
608 buf_printf(b, "\"depends=");
609 for (s = mod->unres; s; s = s->next) {
610 if (!s->module)
611 continue;
612
613 if (s->module->seen)
614 continue;
615
616 s->module->seen = 1;
617 buf_printf(b, "%s%s", first ? "" : ",",
618 strrchr(s->module->name, '/') + 1);
619 first = 0;
620 }
621 buf_printf(b, "\";\n");
622}
623
624void
625add_srcversion(struct buffer *b, struct module *mod)
626{
627 if (mod->srcversion[0]) {
628 buf_printf(b, "\n");
629 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
630 mod->srcversion);
631 }
632}
633
634void
635write_if_changed(struct buffer *b, const char *fname)
636{
637 char *tmp;
638 FILE *file;
639 struct stat st;
640
641 file = fopen(fname, "r");
642 if (!file)
643 goto write;
644
645 if (fstat(fileno(file), &st) < 0)
646 goto close_write;
647
648 if (st.st_size != b->pos)
649 goto close_write;
650
651 tmp = NOFAIL(malloc(b->pos));
652 if (fread(tmp, 1, b->pos, file) != b->pos)
653 goto free_write;
654
655 if (memcmp(tmp, b->p, b->pos) != 0)
656 goto free_write;
657
658 free(tmp);
659 fclose(file);
660 return;
661
662 free_write:
663 free(tmp);
664 close_write:
665 fclose(file);
666 write:
667 file = fopen(fname, "w");
668 if (!file) {
669 perror(fname);
670 exit(1);
671 }
672 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
673 perror(fname);
674 exit(1);
675 }
676 fclose(file);
677}
678
679void
680read_dump(const char *fname)
681{
682 unsigned long size, pos = 0;
683 void *file = grab_file(fname, &size);
684 char *line;
685
686 if (!file)
687 /* No symbol versions, silently ignore */
688 return;
689
690 while ((line = get_next_line(&pos, file, size))) {
691 char *symname, *modname, *d;
692 unsigned int crc;
693 struct module *mod;
694
695 if (!(symname = strchr(line, '\t')))
696 goto fail;
697 *symname++ = '\0';
698 if (!(modname = strchr(symname, '\t')))
699 goto fail;
700 *modname++ = '\0';
701 if (strchr(modname, '\t'))
702 goto fail;
703 crc = strtoul(line, &d, 16);
704 if (*symname == '\0' || *modname == '\0' || *d != '\0')
705 goto fail;
706
707 if (!(mod = find_module(modname))) {
708 if (is_vmlinux(modname)) {
709 have_vmlinux = 1;
710 }
711 mod = new_module(NOFAIL(strdup(modname)));
712 mod->skip = 1;
713 }
714 add_exported_symbol(symname, mod, &crc);
715 }
716 return;
717fail:
718 fatal("parse error in symbol dump file\n");
719}
720
721void
722write_dump(const char *fname)
723{
724 struct buffer buf = { };
725 struct symbol *symbol;
726 int n;
727
728 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
729 symbol = symbolhash[n];
730 while (symbol) {
731 symbol = symbol->next;
732 }
733 }
734
735 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
736 symbol = symbolhash[n];
737 while (symbol) {
738 buf_printf(&buf, "0x%08x\t%s\t%s\n", symbol->crc,
739 symbol->name, symbol->module->name);
740 symbol = symbol->next;
741 }
742 }
743 write_if_changed(&buf, fname);
744}
745
746int
747main(int argc, char **argv)
748{
749 struct module *mod;
750 struct buffer buf = { };
751 char fname[SZ];
752 char *dump_read = NULL, *dump_write = NULL;
753 int opt;
754
755 while ((opt = getopt(argc, argv, "i:mo:a")) != -1) {
756 switch(opt) {
757 case 'i':
758 dump_read = optarg;
759 break;
760 case 'm':
761 modversions = 1;
762 break;
763 case 'o':
764 dump_write = optarg;
765 break;
766 case 'a':
767 all_versions = 1;
768 break;
769 default:
770 exit(1);
771 }
772 }
773
774 if (dump_read)
775 read_dump(dump_read);
776
777 while (optind < argc) {
778 read_symbols(argv[optind++]);
779 }
780
781 for (mod = modules; mod; mod = mod->next) {
782 if (mod->skip)
783 continue;
784
785 buf.pos = 0;
786
787 add_header(&buf, mod);
788 add_versions(&buf, mod);
789 add_depends(&buf, mod, modules);
790 add_moddevtable(&buf, mod);
791 add_srcversion(&buf, mod);
792
793 sprintf(fname, "%s.mod.c", mod->name);
794 write_if_changed(&buf, fname);
795 }
796
797 if (dump_write)
798 write_dump(dump_write);
799
800 return 0;
801}
802