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meta: update various documentation, logs, authors, etc.
[mit.git] / elfops_core.c
blob1495f6871bb5a1f182755471f39315f5e011f327
1 #if defined(ELF32BIT)
2
3 #define PERBIT(x) x##32
4 #define ElfPERBIT(x) Elf32_##x
5 #define ELFPERBIT(x) ELF32_##x
6 /* 32-bit unsigned integer */
7 #define Elf32_Uint Elf32_Word
8
9 #elif defined(ELF64BIT)
10
11 #define PERBIT(x) x##64
12 #define ElfPERBIT(x) Elf64_##x
13 #define ELFPERBIT(x) ELF64_##x
14 /* 64-bit unsigned integer */
15 #define Elf64_Uint Elf64_Xword
16
17 #else
18 # error "Undefined ELF word length"
19 #endif
20
21 static void *PERBIT(get_section)(struct elf_file *module,
22 const char *secname,
23 ElfPERBIT(Shdr) **sechdr,
24 unsigned long *secsize)
25 {
26 void *data = module->data;
27 unsigned long len = module->len;
28 int conv = module->conv;
29
30 ElfPERBIT(Ehdr) *hdr;
31 ElfPERBIT(Shdr) *sechdrs;
32 ElfPERBIT(Off) e_shoff;
33 ElfPERBIT(Half) e_shnum, e_shstrndx;
34 ElfPERBIT(Off) secoffset;
35
36 const char *secnames;
37 unsigned int i;
38
39 *secsize = 0;
40
41 if (len <= 0 || len < sizeof(*hdr))
42 return NULL;
43
44 hdr = data;
45 e_shoff = END(hdr->e_shoff, conv);
46 e_shnum = END(hdr->e_shnum, conv);
47 e_shstrndx = END(hdr->e_shstrndx, conv);
48
49 if (len < e_shoff + e_shnum * sizeof(sechdrs[0]))
50 return NULL;
51
52 sechdrs = data + e_shoff;
53
54 if (len < END(sechdrs[e_shstrndx].sh_offset, conv))
55 return NULL;
56
57 /* Find section by name; return header, pointer and size. */
58 secnames = data + END(sechdrs[e_shstrndx].sh_offset, conv);
59 for (i = 1; i < e_shnum; i++) {
60 if (streq(secnames + END(sechdrs[i].sh_name, conv), secname)) {
61 *secsize = END(sechdrs[i].sh_size, conv);
62 secoffset = END(sechdrs[i].sh_offset, conv);
63 if (sechdr)
64 *sechdr = sechdrs + i;
65 if (len < secoffset + *secsize)
66 return NULL;
67 return data + secoffset;
68 }
69 }
70 return NULL;
71 }
72
73 /* Load the given section: NULL on error. */
74 static void *PERBIT(load_section)(struct elf_file *module,
75 const char *secname,
76 unsigned long *secsize)
77 {
78 return PERBIT(get_section)(module, secname, NULL, secsize);
79 }
80
81 static struct string_table *PERBIT(load_strings)(struct elf_file *module,
82 const char *secname,
83 struct string_table *tbl,
84 errfn_t error)
85 {
86 unsigned long size;
87 const char *strings;
88
89 strings = PERBIT(load_section)(module, secname, &size);
90 if (strings) {
91 /* Skip any zero padding. */
92 while (!strings[0]) {
93 strings++;
94 if (size-- <= 1)
95 return tbl;
96 }
97 for (; strings; strings = next_string(strings, &size))
98 tbl = NOFAIL(strtbl_add(strings, tbl));
99 }
100 return tbl;
101 }
102
103 static struct string_table *PERBIT(load_symbols)(struct elf_file *module,
104 uint64_t **versions)
105 {
106 struct string_table *symtbl = NULL;
107
108 if (versions) {
109 static const char crc[] = "__crc_";
110 static const int crc_len = sizeof(crc) - 1;
111 unsigned int num_syms, i;
112 unsigned long size;
113 ElfPERBIT(Sym) *syms;
114 char *strings;
115 int conv;
116
117 *versions = NULL;
118 strings = PERBIT(load_section)(module, ".strtab", &size);
119 syms = PERBIT(load_section)(module, ".symtab", &size);
120 if (!strings || !syms)
121 goto fallback;
122 num_syms = size / sizeof(syms[0]);
123 *versions = NOFAIL(calloc(sizeof(**versions), num_syms));
124
125 conv = module->conv;
126 for (i = 1; i < num_syms; i++) {
127 const char *name;
128 name = strings + END(syms[i].st_name, conv);
129 if (strncmp(name, crc, crc_len) != 0)
130 continue;
131 name += crc_len;
132 symtbl = NOFAIL(strtbl_add(name, symtbl));
133 (*versions)[symtbl->cnt - 1] = END(syms[i].st_value,
134 conv);
135 }
136 if (!symtbl) {
137 /* Either this module does not export any symbols, or
138 * it was compiled without CONFIG_MODVERSIONS. If the
139 * latter, we will print a warning in load_dep_syms,
140 * so just silently fallback to __ksymtab_strings in
141 * both cases.
142 */
143 free(*versions);
144 *versions = NULL;
145 goto fallback;
146 }
147 return symtbl;
148 }
149 fallback:
150 return PERBIT(load_strings)(module, "__ksymtab_strings", symtbl,
151 fatal);
152 }
153
154 static char *PERBIT(get_aliases)(struct elf_file *module, unsigned long *size)
155 {
156 return PERBIT(load_section)(module, ".modalias", size);
157 }
158
159 static char *PERBIT(get_modinfo)(struct elf_file *module, unsigned long *size)
160 {
161 return PERBIT(load_section)(module, ".modinfo", size);
162 }
163
164 #ifndef STT_REGISTER
165 #define STT_REGISTER 13 /* Global register reserved to app. */
166 #endif
167
168 static struct string_table *PERBIT(load_dep_syms)(struct elf_file *module,
169 struct string_table **types,
170 uint64_t **versions)
171 {
172 unsigned int i, num_syms;
173 unsigned int j, num_symvers, versions_size;
174 unsigned long size;
175 char *strings;
176 ElfPERBIT(Sym) *syms;
177 ElfPERBIT(Ehdr) *hdr;
178 struct PERBIT(modver_info) **symvers;
179 int handle_register_symbols;
180 struct string_table *names;
181 int conv;
182
183 names = NULL;
184 *types = NULL;
185 symvers = NULL;
186 num_symvers = versions_size = 0;
187
188 if (versions) {
189 int ok = 1;
190 *versions = NULL;
191 struct PERBIT(modver_info) *symvers_sec;
192
193 symvers_sec = module->ops->load_section(module, "__versions",
194 &size);
195 if (!symvers_sec) {
196 warn("%s is built without modversions",
197 module->pathname);
198 ok = 0;
199 }
200 if (size % sizeof(symvers[0]) != 0) {
201 warn("invalid __versions section size in %s",
202 module->pathname);
203 ok = 0;
204 }
205 if (ok) {
206 num_symvers = size / sizeof(symvers_sec[0]);
207 /* symvers is used to keep track of each visited entry.
208 * The table also contains the fake struct_module /
209 * module_layout symbol which we don't want to miss.
210 */
211 symvers = NOFAIL(malloc(num_symvers *
212 sizeof(symvers[0])));
213 for (j = 0; j < num_symvers; j++)
214 symvers[j] = &symvers_sec[j];
215 } else {
216 versions = NULL;
217 }
218 }
219
220 strings = PERBIT(load_section)(module, ".strtab", &size);
221 syms = PERBIT(load_section)(module, ".symtab", &size);
222 if (!strings || !syms) {
223 warn("Couldn't find symtab and strtab in module %s\n",
224 module->pathname);
225 goto out;
226 }
227
228 num_syms = size / sizeof(syms[0]);
229 hdr = module->data;
230 conv = module->conv;
231 if (versions) {
232 versions_size = num_syms;
233 *versions = NOFAIL(calloc(sizeof(**versions), versions_size));
234 }
235
236 handle_register_symbols =
237 (END(hdr->e_machine, conv) == EM_SPARC ||
238 END(hdr->e_machine, conv) == EM_SPARCV9);
239
240 for (i = 1; i < num_syms; i++) {
241 if (END(syms[i].st_shndx, conv) == SHN_UNDEF) {
242 /* Look for symbol */
243 const char *name;
244 int weak;
245
246 name = strings + END(syms[i].st_name, conv);
247
248 /* Not really undefined: sparc gcc 3.3 creates
249 U references when you have global asm
250 variables, to avoid anyone else misusing
251 them. */
252 if (handle_register_symbols
253 && (ELFPERBIT(ST_TYPE)(END(syms[i].st_info, conv))
254 == STT_REGISTER))
255 continue;
256
257 weak = (ELFPERBIT(ST_BIND)(END(syms[i].st_info, conv))
258 == STB_WEAK);
259 names = NOFAIL(strtbl_add(name, names));
260 *types = NOFAIL(strtbl_add(weak ? weak_sym : undef_sym,
261 *types));
262
263 if (!versions)
264 continue;
265 /* Not optimal, but the number of required symbols
266 * is usually not huge and this is only called by
267 * depmod.
268 */
269 for (j = 0; j < num_symvers; j++) {
270 struct PERBIT(modver_info) *info = symvers[j];
271
272 if (!info)
273 continue;
274 if (streq(name, info->name)) {
275 (*versions)[names->cnt - 1] =
276 END(info->crc, conv);
277 symvers[j] = NULL;
278 break;
279 }
280 }
281 }
282 }
283 /* add struct_module / module_layout */
284 for (j = 0; j < num_symvers; j++) {
285 struct PERBIT(modver_info) *info = symvers[j];
286
287 if (!info)
288 continue;
289 if ((names ? names->cnt : 0) >= versions_size) {
290 versions_size++;
291 *versions = NOFAIL(realloc(*versions, versions_size));
292 }
293 names = NOFAIL(strtbl_add(info->name, names));
294 *types = NOFAIL(strtbl_add(undef_sym, *types));
295 (*versions)[names->cnt - 1] = END(info->crc, conv);
296 }
297 out:
298 free(symvers);
299 return names;
300 }
301
302 static void *PERBIT(deref_sym)(ElfPERBIT(Ehdr) *hdr,
303 ElfPERBIT(Shdr) *sechdrs,
304 ElfPERBIT(Sym) *sym,
305 unsigned int *secsize,
306 int conv)
307 {
308 /* In BSS? Happens for empty device tables on
309 * recent GCC versions. */
310 if (END(sechdrs[END(sym->st_shndx, conv)].sh_type,conv) == SHT_NOBITS)
311 return NULL;
312
313 if (secsize)
314 *secsize = END(sym->st_size, conv);
315 return (void *)hdr
316 + END(sechdrs[END(sym->st_shndx, conv)].sh_offset, conv)
317 + END(sym->st_value, conv);
318 }
319
320 /* FIXME: Check size, unless we end up using aliases anyway --RR */
321 static void PERBIT(fetch_tables)(struct elf_file *module,
322 struct module_tables *tables)
323 {
324 unsigned int i;
325 unsigned long size;
326 char *strings;
327 ElfPERBIT(Ehdr) *hdr;
328 ElfPERBIT(Sym) *syms;
329 ElfPERBIT(Shdr) *sechdrs;
330 int conv;
331
332 hdr = module->data;
333 conv = module->conv;
334
335 sechdrs = (void *)hdr + END(hdr->e_shoff, conv);
336 strings = PERBIT(load_section)(module, ".strtab", &size);
337 syms = PERBIT(load_section)(module, ".symtab", &size);
338
339 /* Don't warn again: we already have above */
340 if (!strings || !syms)
341 return;
342
343 memset(tables, 0x00, sizeof(struct module_tables));
344
345 for (i = 0; i < size / sizeof(syms[0]); i++) {
346 char *name = strings + END(syms[i].st_name, conv);
347
348 if (!tables->pci_table && streq(name, "__mod_pci_device_table")) {
349 tables->pci_size = PERBIT(PCI_DEVICE_SIZE);
350 tables->pci_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
351 NULL, conv);
352 }
353 else if (!tables->usb_table && streq(name, "__mod_usb_device_table")) {
354 tables->usb_size = PERBIT(USB_DEVICE_SIZE);
355 tables->usb_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
356 NULL, conv);
357 }
358 else if (!tables->ccw_table && streq(name, "__mod_ccw_device_table")) {
359 tables->ccw_size = PERBIT(CCW_DEVICE_SIZE);
360 tables->ccw_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
361 NULL, conv);
362 }
363 else if (!tables->ieee1394_table && streq(name, "__mod_ieee1394_device_table")) {
364 tables->ieee1394_size = PERBIT(IEEE1394_DEVICE_SIZE);
365 tables->ieee1394_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
366 NULL, conv);
367 }
368 else if (!tables->pnp_table && streq(name, "__mod_pnp_device_table")) {
369 tables->pnp_size = PERBIT(PNP_DEVICE_SIZE);
370 tables->pnp_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
371 NULL, conv);
372 }
373 else if (!tables->pnp_card_table && streq(name, "__mod_pnp_card_device_table")) {
374 tables->pnp_card_size = PERBIT(PNP_CARD_DEVICE_SIZE);
375 tables->pnp_card_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
376 NULL, conv);
377 tables->pnp_card_offset = PERBIT(PNP_CARD_DEVICE_OFFSET);
378 }
379 else if (!tables->input_table && streq(name, "__mod_input_device_table")) {
380 tables->input_size = PERBIT(INPUT_DEVICE_SIZE);
381 tables->input_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
382 &tables->input_table_size,
383 conv);
384 }
385 else if (!tables->serio_table && streq(name, "__mod_serio_device_table")) {
386 tables->serio_size = PERBIT(SERIO_DEVICE_SIZE);
387 tables->serio_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
388 NULL, conv);
389 }
390 else if (!tables->of_table && streq(name, "__mod_of_device_table")) {
391 tables->of_size = PERBIT(OF_DEVICE_SIZE);
392 tables->of_table = PERBIT(deref_sym)(hdr, sechdrs, &syms[i],
393 NULL, conv);
394 }
395 }
396 }
397
398 /*
399 * strip_section - tell the kernel to ignore the named section
400 */
401 static void PERBIT(strip_section)(struct elf_file *module, const char *secname)
402 {
403 void *p;
404 ElfPERBIT(Shdr) *sechdr;
405 unsigned long secsize;
406
407 p = PERBIT(get_section)(module, secname, &sechdr, &secsize);
408 if (p) {
409 ElfPERBIT(Uint) mask;
410 mask = ~((ElfPERBIT(Uint))SHF_ALLOC);
411 sechdr->sh_flags &= END(mask, module->conv);
412 }
413 }
414
415 static int PERBIT(dump_modversions)(struct elf_file *module)
416 {
417 unsigned long secsize;
418 struct PERBIT(modver_info) *info;
419 int n = 0;
420
421 info = module->ops->load_section(module, "__versions", &secsize);
422 if (!info)
423 return 0; /* not a kernel module */
424 if (secsize % sizeof(*info) != 0)
425 return -1; /* invalid section size */
426
427 for (n = 0; n < secsize / sizeof(*info); n++) {
428 #if defined(ELF32BIT)
429 printf("0x%08lx\t%s\n", (unsigned long)
430 #else /* defined(ELF64BIT) */
431 printf("0x%08llx\t%s\n", (unsigned long long)
432 #endif
433 END(info[n].crc, module->conv),
434 skip_dot(info[n].name));
435 }
436 return n;
437 }
438
439 struct module_ops PERBIT(mod_ops) = {
440 .load_section = PERBIT(load_section),
441 .load_strings = PERBIT(load_strings),
442 .load_symbols = PERBIT(load_symbols),
443 .load_dep_syms = PERBIT(load_dep_syms),
444 .fetch_tables = PERBIT(fetch_tables),
445 .get_aliases = PERBIT(get_aliases),
446 .get_modinfo = PERBIT(get_modinfo),
447 .strip_section = PERBIT(strip_section),
448 .dump_modvers = PERBIT(dump_modversions),
449 };
450
451 #undef PERBIT
452 #undef ElfPERBIT
453 #undef ELFPERBIT
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