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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* Helpers for initial module or kernel cmdline parsing | |
3 | Copyright (C) 2001 Rusty Russell. | |
4 | ||
5 | */ | |
6 | #include <linux/kernel.h> | |
7 | #include <linux/string.h> | |
8 | #include <linux/errno.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/moduleparam.h> | |
11 | #include <linux/device.h> | |
12 | #include <linux/err.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/ctype.h> | |
15 | ||
16 | #ifdef CONFIG_SYSFS | |
17 | /* Protects all built-in parameters, modules use their own param_lock */ | |
18 | static DEFINE_MUTEX(param_lock); | |
19 | ||
20 | /* Use the module's mutex, or if built-in use the built-in mutex */ | |
21 | #ifdef CONFIG_MODULES | |
22 | #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : ¶m_lock) | |
23 | #else | |
24 | #define KPARAM_MUTEX(mod) (¶m_lock) | |
25 | #endif | |
26 | ||
27 | static inline void check_kparam_locked(struct module *mod) | |
28 | { | |
29 | BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod))); | |
30 | } | |
31 | #else | |
32 | static inline void check_kparam_locked(struct module *mod) | |
33 | { | |
34 | } | |
35 | #endif /* !CONFIG_SYSFS */ | |
36 | ||
37 | /* This just allows us to keep track of which parameters are kmalloced. */ | |
38 | struct kmalloced_param { | |
39 | struct list_head list; | |
40 | char val[]; | |
41 | }; | |
42 | static LIST_HEAD(kmalloced_params); | |
43 | static DEFINE_SPINLOCK(kmalloced_params_lock); | |
44 | ||
45 | static void *kmalloc_parameter(unsigned int size) | |
46 | { | |
47 | struct kmalloced_param *p; | |
48 | ||
49 | p = kmalloc(sizeof(*p) + size, GFP_KERNEL); | |
50 | if (!p) | |
51 | return NULL; | |
52 | ||
53 | spin_lock(&kmalloced_params_lock); | |
54 | list_add(&p->list, &kmalloced_params); | |
55 | spin_unlock(&kmalloced_params_lock); | |
56 | ||
57 | return p->val; | |
58 | } | |
59 | ||
60 | /* Does nothing if parameter wasn't kmalloced above. */ | |
61 | static void maybe_kfree_parameter(void *param) | |
62 | { | |
63 | struct kmalloced_param *p; | |
64 | ||
65 | spin_lock(&kmalloced_params_lock); | |
66 | list_for_each_entry(p, &kmalloced_params, list) { | |
67 | if (p->val == param) { | |
68 | list_del(&p->list); | |
69 | kfree(p); | |
70 | break; | |
71 | } | |
72 | } | |
73 | spin_unlock(&kmalloced_params_lock); | |
74 | } | |
75 | ||
76 | static char dash2underscore(char c) | |
77 | { | |
78 | if (c == '-') | |
79 | return '_'; | |
80 | return c; | |
81 | } | |
82 | ||
83 | bool parameqn(const char *a, const char *b, size_t n) | |
84 | { | |
85 | size_t i; | |
86 | ||
87 | for (i = 0; i < n; i++) { | |
88 | if (dash2underscore(a[i]) != dash2underscore(b[i])) | |
89 | return false; | |
90 | } | |
91 | return true; | |
92 | } | |
93 | ||
94 | bool parameq(const char *a, const char *b) | |
95 | { | |
96 | return parameqn(a, b, strlen(a)+1); | |
97 | } | |
98 | ||
99 | static bool param_check_unsafe(const struct kernel_param *kp, | |
100 | const char *doing) | |
101 | { | |
102 | if (kp->flags & KERNEL_PARAM_FL_UNSAFE) { | |
103 | pr_notice("Setting dangerous option %s - tainting kernel\n", | |
104 | kp->name); | |
105 | add_taint(TAINT_USER, LOCKDEP_STILL_OK); | |
106 | } | |
107 | ||
108 | if (kp->flags & KERNEL_PARAM_FL_HWPARAM && | |
109 | kernel_is_locked_down("Command line-specified device addresses, irqs and dma channels")) | |
110 | return false; | |
111 | return true; | |
112 | } | |
113 | ||
114 | static int parse_one(char *param, | |
115 | char *val, | |
116 | const char *doing, | |
117 | const struct kernel_param *params, | |
118 | unsigned num_params, | |
119 | s16 min_level, | |
120 | s16 max_level, | |
121 | void *arg, | |
122 | int (*handle_unknown)(char *param, char *val, | |
123 | const char *doing, void *arg)) | |
124 | { | |
125 | unsigned int i; | |
126 | int err; | |
127 | ||
128 | /* Find parameter */ | |
129 | for (i = 0; i < num_params; i++) { | |
130 | if (parameq(param, params[i].name)) { | |
131 | if (params[i].level < min_level | |
132 | || params[i].level > max_level) | |
133 | return 0; | |
134 | /* No one handled NULL, so do it here. */ | |
135 | if (!val && | |
136 | !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG)) | |
137 | return -EINVAL; | |
138 | pr_debug("handling %s with %p\n", param, | |
139 | params[i].ops->set); | |
140 | kernel_param_lock(params[i].mod); | |
141 | if (param_check_unsafe(¶ms[i], doing)) | |
142 | err = params[i].ops->set(val, ¶ms[i]); | |
143 | else | |
144 | err = -EPERM; | |
145 | kernel_param_unlock(params[i].mod); | |
146 | return err; | |
147 | } | |
148 | } | |
149 | ||
150 | if (handle_unknown) { | |
151 | pr_debug("doing %s: %s='%s'\n", doing, param, val); | |
152 | return handle_unknown(param, val, doing, arg); | |
153 | } | |
154 | ||
155 | pr_debug("Unknown argument '%s'\n", param); | |
156 | return -ENOENT; | |
157 | } | |
158 | ||
159 | /* Args looks like "foo=bar,bar2 baz=fuz wiz". */ | |
160 | char *parse_args(const char *doing, | |
161 | char *args, | |
162 | const struct kernel_param *params, | |
163 | unsigned num, | |
164 | s16 min_level, | |
165 | s16 max_level, | |
166 | void *arg, | |
167 | int (*unknown)(char *param, char *val, | |
168 | const char *doing, void *arg)) | |
169 | { | |
170 | char *param, *val, *err = NULL; | |
171 | ||
172 | /* Chew leading spaces */ | |
173 | args = skip_spaces(args); | |
174 | ||
175 | if (*args) | |
176 | pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args); | |
177 | ||
178 | while (*args) { | |
179 | int ret; | |
180 | int irq_was_disabled; | |
181 | ||
182 | args = next_arg(args, ¶m, &val); | |
183 | /* Stop at -- */ | |
184 | if (!val && strcmp(param, "--") == 0) | |
185 | return err ?: args; | |
186 | irq_was_disabled = irqs_disabled(); | |
187 | ret = parse_one(param, val, doing, params, num, | |
188 | min_level, max_level, arg, unknown); | |
189 | if (irq_was_disabled && !irqs_disabled()) | |
190 | pr_warn("%s: option '%s' enabled irq's!\n", | |
191 | doing, param); | |
192 | ||
193 | switch (ret) { | |
194 | case 0: | |
195 | continue; | |
196 | case -ENOENT: | |
197 | pr_err("%s: Unknown parameter `%s'\n", doing, param); | |
198 | break; | |
199 | case -ENOSPC: | |
200 | pr_err("%s: `%s' too large for parameter `%s'\n", | |
201 | doing, val ?: "", param); | |
202 | break; | |
203 | default: | |
204 | pr_err("%s: `%s' invalid for parameter `%s'\n", | |
205 | doing, val ?: "", param); | |
206 | break; | |
207 | } | |
208 | ||
209 | err = ERR_PTR(ret); | |
210 | } | |
211 | ||
212 | return err; | |
213 | } | |
214 | ||
215 | /* Lazy bastard, eh? */ | |
216 | #define STANDARD_PARAM_DEF(name, type, format, strtolfn) \ | |
217 | int param_set_##name(const char *val, const struct kernel_param *kp) \ | |
218 | { \ | |
219 | return strtolfn(val, 0, (type *)kp->arg); \ | |
220 | } \ | |
221 | int param_get_##name(char *buffer, const struct kernel_param *kp) \ | |
222 | { \ | |
223 | return scnprintf(buffer, PAGE_SIZE, format "\n", \ | |
224 | *((type *)kp->arg)); \ | |
225 | } \ | |
226 | const struct kernel_param_ops param_ops_##name = { \ | |
227 | .set = param_set_##name, \ | |
228 | .get = param_get_##name, \ | |
229 | }; \ | |
230 | EXPORT_SYMBOL(param_set_##name); \ | |
231 | EXPORT_SYMBOL(param_get_##name); \ | |
232 | EXPORT_SYMBOL(param_ops_##name) | |
233 | ||
234 | ||
235 | STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8); | |
236 | STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16); | |
237 | STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16); | |
238 | STANDARD_PARAM_DEF(int, int, "%i", kstrtoint); | |
239 | STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint); | |
240 | STANDARD_PARAM_DEF(long, long, "%li", kstrtol); | |
241 | STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul); | |
242 | STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull); | |
243 | ||
244 | int param_set_charp(const char *val, const struct kernel_param *kp) | |
245 | { | |
246 | if (strlen(val) > 1024) { | |
247 | pr_err("%s: string parameter too long\n", kp->name); | |
248 | return -ENOSPC; | |
249 | } | |
250 | ||
251 | maybe_kfree_parameter(*(char **)kp->arg); | |
252 | ||
253 | /* This is a hack. We can't kmalloc in early boot, and we | |
254 | * don't need to; this mangled commandline is preserved. */ | |
255 | if (slab_is_available()) { | |
256 | *(char **)kp->arg = kmalloc_parameter(strlen(val)+1); | |
257 | if (!*(char **)kp->arg) | |
258 | return -ENOMEM; | |
259 | strcpy(*(char **)kp->arg, val); | |
260 | } else | |
261 | *(const char **)kp->arg = val; | |
262 | ||
263 | return 0; | |
264 | } | |
265 | EXPORT_SYMBOL(param_set_charp); | |
266 | ||
267 | int param_get_charp(char *buffer, const struct kernel_param *kp) | |
268 | { | |
269 | return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg)); | |
270 | } | |
271 | EXPORT_SYMBOL(param_get_charp); | |
272 | ||
273 | void param_free_charp(void *arg) | |
274 | { | |
275 | maybe_kfree_parameter(*((char **)arg)); | |
276 | } | |
277 | EXPORT_SYMBOL(param_free_charp); | |
278 | ||
279 | const struct kernel_param_ops param_ops_charp = { | |
280 | .set = param_set_charp, | |
281 | .get = param_get_charp, | |
282 | .free = param_free_charp, | |
283 | }; | |
284 | EXPORT_SYMBOL(param_ops_charp); | |
285 | ||
286 | /* Actually could be a bool or an int, for historical reasons. */ | |
287 | int param_set_bool(const char *val, const struct kernel_param *kp) | |
288 | { | |
289 | /* No equals means "set"... */ | |
290 | if (!val) val = "1"; | |
291 | ||
292 | /* One of =[yYnN01] */ | |
293 | return strtobool(val, kp->arg); | |
294 | } | |
295 | EXPORT_SYMBOL(param_set_bool); | |
296 | ||
297 | int param_get_bool(char *buffer, const struct kernel_param *kp) | |
298 | { | |
299 | /* Y and N chosen as being relatively non-coder friendly */ | |
300 | return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N'); | |
301 | } | |
302 | EXPORT_SYMBOL(param_get_bool); | |
303 | ||
304 | const struct kernel_param_ops param_ops_bool = { | |
305 | .flags = KERNEL_PARAM_OPS_FL_NOARG, | |
306 | .set = param_set_bool, | |
307 | .get = param_get_bool, | |
308 | }; | |
309 | EXPORT_SYMBOL(param_ops_bool); | |
310 | ||
311 | int param_set_bool_enable_only(const char *val, const struct kernel_param *kp) | |
312 | { | |
313 | int err = 0; | |
314 | bool new_value; | |
315 | bool orig_value = *(bool *)kp->arg; | |
316 | struct kernel_param dummy_kp = *kp; | |
317 | ||
318 | dummy_kp.arg = &new_value; | |
319 | ||
320 | err = param_set_bool(val, &dummy_kp); | |
321 | if (err) | |
322 | return err; | |
323 | ||
324 | /* Don't let them unset it once it's set! */ | |
325 | if (!new_value && orig_value) | |
326 | return -EROFS; | |
327 | ||
328 | if (new_value) | |
329 | err = param_set_bool(val, kp); | |
330 | ||
331 | return err; | |
332 | } | |
333 | EXPORT_SYMBOL_GPL(param_set_bool_enable_only); | |
334 | ||
335 | const struct kernel_param_ops param_ops_bool_enable_only = { | |
336 | .flags = KERNEL_PARAM_OPS_FL_NOARG, | |
337 | .set = param_set_bool_enable_only, | |
338 | .get = param_get_bool, | |
339 | }; | |
340 | EXPORT_SYMBOL_GPL(param_ops_bool_enable_only); | |
341 | ||
342 | /* This one must be bool. */ | |
343 | int param_set_invbool(const char *val, const struct kernel_param *kp) | |
344 | { | |
345 | int ret; | |
346 | bool boolval; | |
347 | struct kernel_param dummy; | |
348 | ||
349 | dummy.arg = &boolval; | |
350 | ret = param_set_bool(val, &dummy); | |
351 | if (ret == 0) | |
352 | *(bool *)kp->arg = !boolval; | |
353 | return ret; | |
354 | } | |
355 | EXPORT_SYMBOL(param_set_invbool); | |
356 | ||
357 | int param_get_invbool(char *buffer, const struct kernel_param *kp) | |
358 | { | |
359 | return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y'); | |
360 | } | |
361 | EXPORT_SYMBOL(param_get_invbool); | |
362 | ||
363 | const struct kernel_param_ops param_ops_invbool = { | |
364 | .set = param_set_invbool, | |
365 | .get = param_get_invbool, | |
366 | }; | |
367 | EXPORT_SYMBOL(param_ops_invbool); | |
368 | ||
369 | int param_set_bint(const char *val, const struct kernel_param *kp) | |
370 | { | |
371 | /* Match bool exactly, by re-using it. */ | |
372 | struct kernel_param boolkp = *kp; | |
373 | bool v; | |
374 | int ret; | |
375 | ||
376 | boolkp.arg = &v; | |
377 | ||
378 | ret = param_set_bool(val, &boolkp); | |
379 | if (ret == 0) | |
380 | *(int *)kp->arg = v; | |
381 | return ret; | |
382 | } | |
383 | EXPORT_SYMBOL(param_set_bint); | |
384 | ||
385 | const struct kernel_param_ops param_ops_bint = { | |
386 | .flags = KERNEL_PARAM_OPS_FL_NOARG, | |
387 | .set = param_set_bint, | |
388 | .get = param_get_int, | |
389 | }; | |
390 | EXPORT_SYMBOL(param_ops_bint); | |
391 | ||
392 | /* We break the rule and mangle the string. */ | |
393 | static int param_array(struct module *mod, | |
394 | const char *name, | |
395 | const char *val, | |
396 | unsigned int min, unsigned int max, | |
397 | void *elem, int elemsize, | |
398 | int (*set)(const char *, const struct kernel_param *kp), | |
399 | s16 level, | |
400 | unsigned int *num) | |
401 | { | |
402 | int ret; | |
403 | struct kernel_param kp; | |
404 | char save; | |
405 | ||
406 | /* Get the name right for errors. */ | |
407 | kp.name = name; | |
408 | kp.arg = elem; | |
409 | kp.level = level; | |
410 | ||
411 | *num = 0; | |
412 | /* We expect a comma-separated list of values. */ | |
413 | do { | |
414 | int len; | |
415 | ||
416 | if (*num == max) { | |
417 | pr_err("%s: can only take %i arguments\n", name, max); | |
418 | return -EINVAL; | |
419 | } | |
420 | len = strcspn(val, ","); | |
421 | ||
422 | /* nul-terminate and parse */ | |
423 | save = val[len]; | |
424 | ((char *)val)[len] = '\0'; | |
425 | check_kparam_locked(mod); | |
426 | ret = set(val, &kp); | |
427 | ||
428 | if (ret != 0) | |
429 | return ret; | |
430 | kp.arg += elemsize; | |
431 | val += len+1; | |
432 | (*num)++; | |
433 | } while (save == ','); | |
434 | ||
435 | if (*num < min) { | |
436 | pr_err("%s: needs at least %i arguments\n", name, min); | |
437 | return -EINVAL; | |
438 | } | |
439 | return 0; | |
440 | } | |
441 | ||
442 | static int param_array_set(const char *val, const struct kernel_param *kp) | |
443 | { | |
444 | const struct kparam_array *arr = kp->arr; | |
445 | unsigned int temp_num; | |
446 | ||
447 | return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem, | |
448 | arr->elemsize, arr->ops->set, kp->level, | |
449 | arr->num ?: &temp_num); | |
450 | } | |
451 | ||
452 | static int param_array_get(char *buffer, const struct kernel_param *kp) | |
453 | { | |
454 | int i, off, ret; | |
455 | const struct kparam_array *arr = kp->arr; | |
456 | struct kernel_param p = *kp; | |
457 | ||
458 | for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) { | |
459 | /* Replace \n with comma */ | |
460 | if (i) | |
461 | buffer[off - 1] = ','; | |
462 | p.arg = arr->elem + arr->elemsize * i; | |
463 | check_kparam_locked(p.mod); | |
464 | ret = arr->ops->get(buffer + off, &p); | |
465 | if (ret < 0) | |
466 | return ret; | |
467 | off += ret; | |
468 | } | |
469 | buffer[off] = '\0'; | |
470 | return off; | |
471 | } | |
472 | ||
473 | static void param_array_free(void *arg) | |
474 | { | |
475 | unsigned int i; | |
476 | const struct kparam_array *arr = arg; | |
477 | ||
478 | if (arr->ops->free) | |
479 | for (i = 0; i < (arr->num ? *arr->num : arr->max); i++) | |
480 | arr->ops->free(arr->elem + arr->elemsize * i); | |
481 | } | |
482 | ||
483 | const struct kernel_param_ops param_array_ops = { | |
484 | .set = param_array_set, | |
485 | .get = param_array_get, | |
486 | .free = param_array_free, | |
487 | }; | |
488 | EXPORT_SYMBOL(param_array_ops); | |
489 | ||
490 | int param_set_copystring(const char *val, const struct kernel_param *kp) | |
491 | { | |
492 | const struct kparam_string *kps = kp->str; | |
493 | ||
494 | if (strlen(val)+1 > kps->maxlen) { | |
495 | pr_err("%s: string doesn't fit in %u chars.\n", | |
496 | kp->name, kps->maxlen-1); | |
497 | return -ENOSPC; | |
498 | } | |
499 | strcpy(kps->string, val); | |
500 | return 0; | |
501 | } | |
502 | EXPORT_SYMBOL(param_set_copystring); | |
503 | ||
504 | int param_get_string(char *buffer, const struct kernel_param *kp) | |
505 | { | |
506 | const struct kparam_string *kps = kp->str; | |
507 | return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string); | |
508 | } | |
509 | EXPORT_SYMBOL(param_get_string); | |
510 | ||
511 | const struct kernel_param_ops param_ops_string = { | |
512 | .set = param_set_copystring, | |
513 | .get = param_get_string, | |
514 | }; | |
515 | EXPORT_SYMBOL(param_ops_string); | |
516 | ||
517 | /* sysfs output in /sys/modules/XYZ/parameters/ */ | |
518 | #define to_module_attr(n) container_of(n, struct module_attribute, attr) | |
519 | #define to_module_kobject(n) container_of(n, struct module_kobject, kobj) | |
520 | ||
521 | struct param_attribute | |
522 | { | |
523 | struct module_attribute mattr; | |
524 | const struct kernel_param *param; | |
525 | }; | |
526 | ||
527 | struct module_param_attrs | |
528 | { | |
529 | unsigned int num; | |
530 | struct attribute_group grp; | |
531 | struct param_attribute attrs[0]; | |
532 | }; | |
533 | ||
534 | #ifdef CONFIG_SYSFS | |
535 | #define to_param_attr(n) container_of(n, struct param_attribute, mattr) | |
536 | ||
537 | static ssize_t param_attr_show(struct module_attribute *mattr, | |
538 | struct module_kobject *mk, char *buf) | |
539 | { | |
540 | int count; | |
541 | struct param_attribute *attribute = to_param_attr(mattr); | |
542 | ||
543 | if (!attribute->param->ops->get) | |
544 | return -EPERM; | |
545 | ||
546 | kernel_param_lock(mk->mod); | |
547 | count = attribute->param->ops->get(buf, attribute->param); | |
548 | kernel_param_unlock(mk->mod); | |
549 | return count; | |
550 | } | |
551 | ||
552 | #ifdef CONFIG_MODULES | |
553 | #define mod_name(mod) (mod)->name | |
554 | #else | |
555 | #define mod_name(mod) "unknown" | |
556 | #endif | |
557 | ||
558 | /* sysfs always hands a nul-terminated string in buf. We rely on that. */ | |
559 | static ssize_t param_attr_store(struct module_attribute *mattr, | |
560 | struct module_kobject *mk, | |
561 | const char *buf, size_t len) | |
562 | { | |
563 | int err; | |
564 | struct param_attribute *attribute = to_param_attr(mattr); | |
565 | ||
566 | if (!attribute->param->ops->set) | |
567 | return -EPERM; | |
568 | ||
569 | kernel_param_lock(mk->mod); | |
570 | if (param_check_unsafe(attribute->param, mod_name(mk->mod))) | |
571 | err = attribute->param->ops->set(buf, attribute->param); | |
572 | else | |
573 | err = -EPERM; | |
574 | kernel_param_unlock(mk->mod); | |
575 | if (!err) | |
576 | return len; | |
577 | return err; | |
578 | } | |
579 | #endif | |
580 | ||
581 | #ifdef CONFIG_MODULES | |
582 | #define __modinit | |
583 | #else | |
584 | #define __modinit __init | |
585 | #endif | |
586 | ||
587 | #ifdef CONFIG_SYSFS | |
588 | void kernel_param_lock(struct module *mod) | |
589 | { | |
590 | mutex_lock(KPARAM_MUTEX(mod)); | |
591 | } | |
592 | ||
593 | void kernel_param_unlock(struct module *mod) | |
594 | { | |
595 | mutex_unlock(KPARAM_MUTEX(mod)); | |
596 | } | |
597 | ||
598 | EXPORT_SYMBOL(kernel_param_lock); | |
599 | EXPORT_SYMBOL(kernel_param_unlock); | |
600 | ||
601 | /* | |
602 | * add_sysfs_param - add a parameter to sysfs | |
603 | * @mk: struct module_kobject | |
604 | * @kp: the actual parameter definition to add to sysfs | |
605 | * @name: name of parameter | |
606 | * | |
607 | * Create a kobject if for a (per-module) parameter if mp NULL, and | |
608 | * create file in sysfs. Returns an error on out of memory. Always cleans up | |
609 | * if there's an error. | |
610 | */ | |
611 | static __modinit int add_sysfs_param(struct module_kobject *mk, | |
612 | const struct kernel_param *kp, | |
613 | const char *name) | |
614 | { | |
615 | struct module_param_attrs *new_mp; | |
616 | struct attribute **new_attrs; | |
617 | unsigned int i; | |
618 | ||
619 | /* We don't bother calling this with invisible parameters. */ | |
620 | BUG_ON(!kp->perm); | |
621 | ||
622 | if (!mk->mp) { | |
623 | /* First allocation. */ | |
624 | mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL); | |
625 | if (!mk->mp) | |
626 | return -ENOMEM; | |
627 | mk->mp->grp.name = "parameters"; | |
628 | /* NULL-terminated attribute array. */ | |
629 | mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]), | |
630 | GFP_KERNEL); | |
631 | /* Caller will cleanup via free_module_param_attrs */ | |
632 | if (!mk->mp->grp.attrs) | |
633 | return -ENOMEM; | |
634 | } | |
635 | ||
636 | /* Enlarge allocations. */ | |
637 | new_mp = krealloc(mk->mp, | |
638 | sizeof(*mk->mp) + | |
639 | sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1), | |
640 | GFP_KERNEL); | |
641 | if (!new_mp) | |
642 | return -ENOMEM; | |
643 | mk->mp = new_mp; | |
644 | ||
645 | /* Extra pointer for NULL terminator */ | |
646 | new_attrs = krealloc(mk->mp->grp.attrs, | |
647 | sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2), | |
648 | GFP_KERNEL); | |
649 | if (!new_attrs) | |
650 | return -ENOMEM; | |
651 | mk->mp->grp.attrs = new_attrs; | |
652 | ||
653 | /* Tack new one on the end. */ | |
654 | memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0])); | |
655 | sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr); | |
656 | mk->mp->attrs[mk->mp->num].param = kp; | |
657 | mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show; | |
658 | /* Do not allow runtime DAC changes to make param writable. */ | |
659 | if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0) | |
660 | mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store; | |
661 | else | |
662 | mk->mp->attrs[mk->mp->num].mattr.store = NULL; | |
663 | mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name; | |
664 | mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm; | |
665 | mk->mp->num++; | |
666 | ||
667 | /* Fix up all the pointers, since krealloc can move us */ | |
668 | for (i = 0; i < mk->mp->num; i++) | |
669 | mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr; | |
670 | mk->mp->grp.attrs[mk->mp->num] = NULL; | |
671 | return 0; | |
672 | } | |
673 | ||
674 | #ifdef CONFIG_MODULES | |
675 | static void free_module_param_attrs(struct module_kobject *mk) | |
676 | { | |
677 | if (mk->mp) | |
678 | kfree(mk->mp->grp.attrs); | |
679 | kfree(mk->mp); | |
680 | mk->mp = NULL; | |
681 | } | |
682 | ||
683 | /* | |
684 | * module_param_sysfs_setup - setup sysfs support for one module | |
685 | * @mod: module | |
686 | * @kparam: module parameters (array) | |
687 | * @num_params: number of module parameters | |
688 | * | |
689 | * Adds sysfs entries for module parameters under | |
690 | * /sys/module/[mod->name]/parameters/ | |
691 | */ | |
692 | int module_param_sysfs_setup(struct module *mod, | |
693 | const struct kernel_param *kparam, | |
694 | unsigned int num_params) | |
695 | { | |
696 | int i, err; | |
697 | bool params = false; | |
698 | ||
699 | for (i = 0; i < num_params; i++) { | |
700 | if (kparam[i].perm == 0) | |
701 | continue; | |
702 | err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name); | |
703 | if (err) { | |
704 | free_module_param_attrs(&mod->mkobj); | |
705 | return err; | |
706 | } | |
707 | params = true; | |
708 | } | |
709 | ||
710 | if (!params) | |
711 | return 0; | |
712 | ||
713 | /* Create the param group. */ | |
714 | err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); | |
715 | if (err) | |
716 | free_module_param_attrs(&mod->mkobj); | |
717 | return err; | |
718 | } | |
719 | ||
720 | /* | |
721 | * module_param_sysfs_remove - remove sysfs support for one module | |
722 | * @mod: module | |
723 | * | |
724 | * Remove sysfs entries for module parameters and the corresponding | |
725 | * kobject. | |
726 | */ | |
727 | void module_param_sysfs_remove(struct module *mod) | |
728 | { | |
729 | if (mod->mkobj.mp) { | |
730 | sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); | |
731 | /* We are positive that no one is using any param | |
732 | * attrs at this point. Deallocate immediately. */ | |
733 | free_module_param_attrs(&mod->mkobj); | |
734 | } | |
735 | } | |
736 | #endif | |
737 | ||
738 | void destroy_params(const struct kernel_param *params, unsigned num) | |
739 | { | |
740 | unsigned int i; | |
741 | ||
742 | for (i = 0; i < num; i++) | |
743 | if (params[i].ops->free) | |
744 | params[i].ops->free(params[i].arg); | |
745 | } | |
746 | ||
747 | static struct module_kobject * __init locate_module_kobject(const char *name) | |
748 | { | |
749 | struct module_kobject *mk; | |
750 | struct kobject *kobj; | |
751 | int err; | |
752 | ||
753 | kobj = kset_find_obj(module_kset, name); | |
754 | if (kobj) { | |
755 | mk = to_module_kobject(kobj); | |
756 | } else { | |
757 | mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL); | |
758 | BUG_ON(!mk); | |
759 | ||
760 | mk->mod = THIS_MODULE; | |
761 | mk->kobj.kset = module_kset; | |
762 | err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, | |
763 | "%s", name); | |
764 | #ifdef CONFIG_MODULES | |
765 | if (!err) | |
766 | err = sysfs_create_file(&mk->kobj, &module_uevent.attr); | |
767 | #endif | |
768 | if (err) { | |
769 | kobject_put(&mk->kobj); | |
770 | pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n", | |
771 | name, err); | |
772 | return NULL; | |
773 | } | |
774 | ||
775 | /* So that we hold reference in both cases. */ | |
776 | kobject_get(&mk->kobj); | |
777 | } | |
778 | ||
779 | return mk; | |
780 | } | |
781 | ||
782 | static void __init kernel_add_sysfs_param(const char *name, | |
783 | const struct kernel_param *kparam, | |
784 | unsigned int name_skip) | |
785 | { | |
786 | struct module_kobject *mk; | |
787 | int err; | |
788 | ||
789 | mk = locate_module_kobject(name); | |
790 | if (!mk) | |
791 | return; | |
792 | ||
793 | /* We need to remove old parameters before adding more. */ | |
794 | if (mk->mp) | |
795 | sysfs_remove_group(&mk->kobj, &mk->mp->grp); | |
796 | ||
797 | /* These should not fail at boot. */ | |
798 | err = add_sysfs_param(mk, kparam, kparam->name + name_skip); | |
799 | BUG_ON(err); | |
800 | err = sysfs_create_group(&mk->kobj, &mk->mp->grp); | |
801 | BUG_ON(err); | |
802 | kobject_uevent(&mk->kobj, KOBJ_ADD); | |
803 | kobject_put(&mk->kobj); | |
804 | } | |
805 | ||
806 | /* | |
807 | * param_sysfs_builtin - add sysfs parameters for built-in modules | |
808 | * | |
809 | * Add module_parameters to sysfs for "modules" built into the kernel. | |
810 | * | |
811 | * The "module" name (KBUILD_MODNAME) is stored before a dot, the | |
812 | * "parameter" name is stored behind a dot in kernel_param->name. So, | |
813 | * extract the "module" name for all built-in kernel_param-eters, | |
814 | * and for all who have the same, call kernel_add_sysfs_param. | |
815 | */ | |
816 | static void __init param_sysfs_builtin(void) | |
817 | { | |
818 | const struct kernel_param *kp; | |
819 | unsigned int name_len; | |
820 | char modname[MODULE_NAME_LEN]; | |
821 | ||
822 | for (kp = __start___param; kp < __stop___param; kp++) { | |
823 | char *dot; | |
824 | ||
825 | if (kp->perm == 0) | |
826 | continue; | |
827 | ||
828 | dot = strchr(kp->name, '.'); | |
829 | if (!dot) { | |
830 | /* This happens for core_param() */ | |
831 | strcpy(modname, "kernel"); | |
832 | name_len = 0; | |
833 | } else { | |
834 | name_len = dot - kp->name + 1; | |
835 | strlcpy(modname, kp->name, name_len); | |
836 | } | |
837 | kernel_add_sysfs_param(modname, kp, name_len); | |
838 | } | |
839 | } | |
840 | ||
841 | ssize_t __modver_version_show(struct module_attribute *mattr, | |
842 | struct module_kobject *mk, char *buf) | |
843 | { | |
844 | struct module_version_attribute *vattr = | |
845 | container_of(mattr, struct module_version_attribute, mattr); | |
846 | ||
847 | return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version); | |
848 | } | |
849 | ||
850 | extern const struct module_version_attribute *__start___modver[]; | |
851 | extern const struct module_version_attribute *__stop___modver[]; | |
852 | ||
853 | static void __init version_sysfs_builtin(void) | |
854 | { | |
855 | const struct module_version_attribute **p; | |
856 | struct module_kobject *mk; | |
857 | int err; | |
858 | ||
859 | for (p = __start___modver; p < __stop___modver; p++) { | |
860 | const struct module_version_attribute *vattr = *p; | |
861 | ||
862 | mk = locate_module_kobject(vattr->module_name); | |
863 | if (mk) { | |
864 | err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr); | |
865 | WARN_ON_ONCE(err); | |
866 | kobject_uevent(&mk->kobj, KOBJ_ADD); | |
867 | kobject_put(&mk->kobj); | |
868 | } | |
869 | } | |
870 | } | |
871 | ||
872 | /* module-related sysfs stuff */ | |
873 | ||
874 | static ssize_t module_attr_show(struct kobject *kobj, | |
875 | struct attribute *attr, | |
876 | char *buf) | |
877 | { | |
878 | struct module_attribute *attribute; | |
879 | struct module_kobject *mk; | |
880 | int ret; | |
881 | ||
882 | attribute = to_module_attr(attr); | |
883 | mk = to_module_kobject(kobj); | |
884 | ||
885 | if (!attribute->show) | |
886 | return -EIO; | |
887 | ||
888 | ret = attribute->show(attribute, mk, buf); | |
889 | ||
890 | return ret; | |
891 | } | |
892 | ||
893 | static ssize_t module_attr_store(struct kobject *kobj, | |
894 | struct attribute *attr, | |
895 | const char *buf, size_t len) | |
896 | { | |
897 | struct module_attribute *attribute; | |
898 | struct module_kobject *mk; | |
899 | int ret; | |
900 | ||
901 | attribute = to_module_attr(attr); | |
902 | mk = to_module_kobject(kobj); | |
903 | ||
904 | if (!attribute->store) | |
905 | return -EIO; | |
906 | ||
907 | ret = attribute->store(attribute, mk, buf, len); | |
908 | ||
909 | return ret; | |
910 | } | |
911 | ||
912 | static const struct sysfs_ops module_sysfs_ops = { | |
913 | .show = module_attr_show, | |
914 | .store = module_attr_store, | |
915 | }; | |
916 | ||
917 | static int uevent_filter(struct kset *kset, struct kobject *kobj) | |
918 | { | |
919 | struct kobj_type *ktype = get_ktype(kobj); | |
920 | ||
921 | if (ktype == &module_ktype) | |
922 | return 1; | |
923 | return 0; | |
924 | } | |
925 | ||
926 | static const struct kset_uevent_ops module_uevent_ops = { | |
927 | .filter = uevent_filter, | |
928 | }; | |
929 | ||
930 | struct kset *module_kset; | |
931 | int module_sysfs_initialized; | |
932 | ||
933 | static void module_kobj_release(struct kobject *kobj) | |
934 | { | |
935 | struct module_kobject *mk = to_module_kobject(kobj); | |
936 | complete(mk->kobj_completion); | |
937 | } | |
938 | ||
939 | struct kobj_type module_ktype = { | |
940 | .release = module_kobj_release, | |
941 | .sysfs_ops = &module_sysfs_ops, | |
942 | }; | |
943 | ||
944 | /* | |
945 | * param_sysfs_init - wrapper for built-in params support | |
946 | */ | |
947 | static int __init param_sysfs_init(void) | |
948 | { | |
949 | module_kset = kset_create_and_add("module", &module_uevent_ops, NULL); | |
950 | if (!module_kset) { | |
951 | printk(KERN_WARNING "%s (%d): error creating kset\n", | |
952 | __FILE__, __LINE__); | |
953 | return -ENOMEM; | |
954 | } | |
955 | module_sysfs_initialized = 1; | |
956 | ||
957 | version_sysfs_builtin(); | |
958 | param_sysfs_builtin(); | |
959 | ||
960 | return 0; | |
961 | } | |
962 | subsys_initcall(param_sysfs_init); | |
963 | ||
964 | #endif /* CONFIG_SYSFS */ |