summaryrefslogtreecommitdiffstats
path: root/kernel/params.c
blob: cbaac85942d5a3fba3856db6908804a12baaf4eb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
/* Helpers for initial module or kernel cmdline parsing
   Copyright (C) 2001 Rusty Russell.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt, a...)
#endif

static inline char dash2underscore(char c)
{
	if (c == '-')
		return '_';
	return c;
}

static inline int parameq(const char *input, const char *paramname)
{
	unsigned int i;
	for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
		if (input[i] == '\0')
			return 1;
	return 0;
}

static int parse_one(char *param,
		     char *val,
		     struct kernel_param *params, 
		     unsigned num_params,
		     int (*handle_unknown)(char *param, char *val))
{
	unsigned int i;

	/* Find parameter */
	for (i = 0; i < num_params; i++) {
		if (parameq(param, params[i].name)) {
			DEBUGP("They are equal!  Calling %p\n",
			       params[i].set);
			return params[i].set(val, &params[i]);
		}
	}

	if (handle_unknown) {
		DEBUGP("Unknown argument: calling %p\n", handle_unknown);
		return handle_unknown(param, val);
	}

	DEBUGP("Unknown argument `%s'\n", param);
	return -ENOENT;
}

/* You can use " around spaces, but can't escape ". */
/* Hyphens and underscores equivalent in parameter names. */
static char *next_arg(char *args, char **param, char **val)
{
	unsigned int i, equals = 0;
	int in_quote = 0, quoted = 0;
	char *next;

	if (*args == '"') {
		args++;
		in_quote = 1;
		quoted = 1;
	}

	for (i = 0; args[i]; i++) {
		if (args[i] == ' ' && !in_quote)
			break;
		if (equals == 0) {
			if (args[i] == '=')
				equals = i;
		}
		if (args[i] == '"')
			in_quote = !in_quote;
	}

	*param = args;
	if (!equals)
		*val = NULL;
	else {
		args[equals] = '\0';
		*val = args + equals + 1;

		/* Don't include quotes in value. */
		if (**val == '"') {
			(*val)++;
			if (args[i-1] == '"')
				args[i-1] = '\0';
		}
		if (quoted && args[i-1] == '"')
			args[i-1] = '\0';
	}

	if (args[i]) {
		args[i] = '\0';
		next = args + i + 1;
	} else
		next = args + i;

	/* Chew up trailing spaces. */
	while (*next == ' ')
		next++;
	return next;
}

/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
int parse_args(const char *name,
	       char *args,
	       struct kernel_param *params,
	       unsigned num,
	       int (*unknown)(char *param, char *val))
{
	char *param, *val;

	DEBUGP("Parsing ARGS: %s\n", args);

	/* Chew leading spaces */
	while (*args == ' ')
		args++;

	while (*args) {
		int ret;
		int irq_was_disabled;

		args = next_arg(args, &param, &val);
		irq_was_disabled = irqs_disabled();
		ret = parse_one(param, val, params, num, unknown);
		if (irq_was_disabled && !irqs_disabled()) {
			printk(KERN_WARNING "parse_args(): option '%s' enabled "
					"irq's!\n", param);
		}
		switch (ret) {
		case -ENOENT:
			printk(KERN_ERR "%s: Unknown parameter `%s'\n",
			       name, param);
			return ret;
		case -ENOSPC:
			printk(KERN_ERR
			       "%s: `%s' too large for parameter `%s'\n",
			       name, val ?: "", param);
			return ret;
		case 0:
			break;
		default:
			printk(KERN_ERR
			       "%s: `%s' invalid for parameter `%s'\n",
			       name, val ?: "", param);
			return ret;
		}
	}

	/* All parsed OK. */
	return 0;
}

/* Lazy bastard, eh? */
#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)      	\
	int param_set_##name(const char *val, struct kernel_param *kp)	\
	{								\
		char *endp;						\
		tmptype l;						\
									\
		if (!val) return -EINVAL;				\
		l = strtolfn(val, &endp, 0);				\
		if (endp == val || ((type)l != l))			\
			return -EINVAL;					\
		*((type *)kp->arg) = l;					\
		return 0;						\
	}								\
	int param_get_##name(char *buffer, struct kernel_param *kp)	\
	{								\
		return sprintf(buffer, format, *((type *)kp->arg));	\
	}

STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, simple_strtoul);
STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, simple_strtoul);
STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, simple_strtoul);
STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);

int param_set_charp(const char *val, struct kernel_param *kp)
{
	if (!val) {
		printk(KERN_ERR "%s: string parameter expected\n",
		       kp->name);
		return -EINVAL;
	}

	if (strlen(val) > 1024) {
		printk(KERN_ERR "%s: string parameter too long\n",
		       kp->name);
		return -ENOSPC;
	}

	*(char **)kp->arg = (char *)val;
	return 0;
}

int param_get_charp(char *buffer, struct kernel_param *kp)
{
	return sprintf(buffer, "%s", *((char **)kp->arg));
}

int param_set_bool(const char *val, struct kernel_param *kp)
{
	/* No equals means "set"... */
	if (!val) val = "1";

	/* One of =[yYnN01] */
	switch (val[0]) {
	case 'y': case 'Y': case '1':
		*(int *)kp->arg = 1;
		return 0;
	case 'n': case 'N': case '0':
		*(int *)kp->arg = 0;
		return 0;
	}
	return -EINVAL;
}

int param_get_bool(char *buffer, struct kernel_param *kp)
{
	/* Y and N chosen as being relatively non-coder friendly */
	return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
}

int param_set_invbool(const char *val, struct kernel_param *kp)
{
	int boolval, ret;
	struct kernel_param dummy = { .arg = &boolval };

	ret = param_set_bool(val, &dummy);
	if (ret == 0)
		*(int *)kp->arg = !boolval;
	return ret;
}

int param_get_invbool(char *buffer, struct kernel_param *kp)
{
	int val;
	struct kernel_param dummy = { .arg = &val };

	val = !*(int *)kp->arg;
	return param_get_bool(buffer, &dummy);
}

/* We cheat here and temporarily mangle the string. */
static int param_array(const char *name,
		       const char *val,
		       unsigned int min, unsigned int max,
		       void *elem, int elemsize,
		       int (*set)(const char *, struct kernel_param *kp),
		       int *num)
{
	int ret;
	struct kernel_param kp;
	char save;

	/* Get the name right for errors. */
	kp.name = name;
	kp.arg = elem;

	/* No equals sign? */
	if (!val) {
		printk(KERN_ERR "%s: expects arguments\n", name);
		return -EINVAL;
	}

	*num = 0;
	/* We expect a comma-separated list of values. */
	do {
		int len;

		if (*num == max) {
			printk(KERN_ERR "%s: can only take %i arguments\n",
			       name, max);
			return -EINVAL;
		}
		len = strcspn(val, ",");

		/* nul-terminate and parse */
		save = val[len];
		((char *)val)[len] = '\0';
		ret = set(val, &kp);

		if (ret != 0)
			return ret;
		kp.arg += elemsize;
		val += len+1;
		(*num)++;
	} while (save == ',');

	if (*num < min) {
		printk(KERN_ERR "%s: needs at least %i arguments\n",
		       name, min);
		return -EINVAL;
	}
	return 0;
}

int param_array_set(const char *val, struct kernel_param *kp)
{
	struct kparam_array *arr = kp->arg;
	unsigned int temp_num;

	return param_array(kp->name, val, 1, arr->max, arr->elem,
			   arr->elemsize, arr->set, arr->num ?: &temp_num);
}

int param_array_get(char *buffer, struct kernel_param *kp)
{
	int i, off, ret;
	struct kparam_array *arr = kp->arg;
	struct kernel_param p;

	p = *kp;
	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
		if (i)
			buffer[off++] = ',';
		p.arg = arr->elem + arr->elemsize * i;
		ret = arr->get(buffer + off, &p);
		if (ret < 0)
			return ret;
		off += ret;
	}
	buffer[off] = '\0';
	return off;
}

int param_set_copystring(const char *val, struct kernel_param *kp)
{
	struct kparam_string *kps = kp->arg;

	if (strlen(val)+1 > kps->maxlen) {
		printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
		       kp->name, kps->maxlen-1);
		return -ENOSPC;
	}
	strcpy(kps->string, val);
	return 0;
}

int param_get_string(char *buffer, struct kernel_param *kp)
{
	struct kparam_string *kps = kp->arg;
	return strlcpy(buffer, kps->string, kps->maxlen);
}

/* sysfs output in /sys/modules/XYZ/parameters/ */

extern struct kernel_param __start___param[], __stop___param[];

#define MAX_KBUILD_MODNAME KOBJ_NAME_LEN

struct param_attribute
{
	struct module_attribute mattr;
	struct kernel_param *param;
};

struct module_param_attrs
{
	struct attribute_group grp;
	struct param_attribute attrs[0];
};

#define to_param_attr(n) container_of(n, struct param_attribute, mattr);

static ssize_t param_attr_show(struct module_attribute *mattr,
			       struct module *mod, char *buf)
{
	int count;
	struct param_attribute *attribute = to_param_attr(mattr);

	if (!attribute->param->get)
		return -EPERM;

	count = attribute->param->get(buf, attribute->param);
	if (count > 0) {
		strcat(buf, "\n");
		++count;
	}
	return count;
}

/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
static ssize_t param_attr_store(struct module_attribute *mattr,
				struct module *owner,
				const char *buf, size_t len)
{
 	int err;
	struct param_attribute *attribute = to_param_attr(mattr);

	if (!attribute->param->set)
		return -EPERM;

	err = attribute->param->set(buf, attribute->param);
	if (!err)
		return len;
	return err;
}

#ifdef CONFIG_MODULES
#define __modinit
#else
#define __modinit __init
#endif

/*
 * param_sysfs_setup - setup sysfs support for one module or KBUILD_MODNAME
 * @mk: struct module_kobject (contains parent kobject)
 * @kparam: array of struct kernel_param, the actual parameter definitions
 * @num_params: number of entries in array
 * @name_skip: offset where the parameter name start in kparam[].name. Needed for built-in "modules"
 *
 * Create a kobject for a (per-module) group of parameters, and create files
 * in sysfs. A pointer to the param_kobject is returned on success,
 * NULL if there's no parameter to export, or other ERR_PTR(err).
 */
static __modinit struct module_param_attrs *
param_sysfs_setup(struct module_kobject *mk,
		  struct kernel_param *kparam,
		  unsigned int num_params,
		  unsigned int name_skip)
{
	struct module_param_attrs *mp;
	unsigned int valid_attrs = 0;
	unsigned int i, size[2];
	struct param_attribute *pattr;
	struct attribute **gattr;
	int err;

	for (i=0; i<num_params; i++) {
		if (kparam[i].perm)
			valid_attrs++;
	}

	if (!valid_attrs)
		return NULL;

	size[0] = ALIGN(sizeof(*mp) +
			valid_attrs * sizeof(mp->attrs[0]),
			sizeof(mp->grp.attrs[0]));
	size[1] = (valid_attrs + 1) * sizeof(mp->grp.attrs[0]);

	mp = kmalloc(size[0] + size[1], GFP_KERNEL);
	if (!mp)
		return ERR_PTR(-ENOMEM);

	mp->grp.name = "parameters";
	mp->grp.attrs = (void *)mp + size[0];

	pattr = &mp->attrs[0];
	gattr = &mp->grp.attrs[0];
	for (i = 0; i < num_params; i++) {
		struct kernel_param *kp = &kparam[i];
		if (kp->perm) {
			pattr->param = kp;
			pattr->mattr.show = param_attr_show;
			pattr->mattr.store = param_attr_store;
			pattr->mattr.attr.name = (char *)&kp->name[name_skip];
			pattr->mattr.attr.owner = mk->mod;
			pattr->mattr.attr.mode = kp->perm;
			*(gattr++) = &(pattr++)->mattr.attr;
		}
	}
	*gattr = NULL;

	if ((err = sysfs_create_group(&mk->kobj, &mp->grp))) {
		kfree(mp);
		return ERR_PTR(err);
	}
	return mp;
}


#ifdef CONFIG_MODULES

/*
 * module_param_sysfs_setup - setup sysfs support for one module
 * @mod: module
 * @kparam: module parameters (array)
 * @num_params: number of module parameters
 *
 * Adds sysfs entries for module parameters, and creates a link from
 * /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
 */
int module_param_sysfs_setup(struct module *mod,
			     struct kernel_param *kparam,
			     unsigned int num_params)
{
	struct module_param_attrs *mp;

	mp = param_sysfs_setup(&mod->mkobj, kparam, num_params, 0);
	if (IS_ERR(mp))
		return PTR_ERR(mp);

	mod->param_attrs = mp;
	return 0;
}

/*
 * module_param_sysfs_remove - remove sysfs support for one module
 * @mod: module
 *
 * Remove sysfs entries for module parameters and the corresponding
 * kobject.
 */
void module_param_sysfs_remove(struct module *mod)
{
	if (mod->param_attrs) {
		sysfs_remove_group(&mod->mkobj.kobj,
				   &mod->param_attrs->grp);
		/* We are positive that no one is using any param
		 * attrs at this point.  Deallocate immediately. */
		kfree(mod->param_attrs);
		mod->param_attrs = NULL;
	}
}
#endif

/*
 * kernel_param_sysfs_setup - wrapper for built-in params support
 */
static void __init kernel_param_sysfs_setup(const char *name,
					    struct kernel_param *kparam,
					    unsigned int num_params,
					    unsigned int name_skip)
{
	struct module_kobject *mk;
	int ret;

	mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
	BUG_ON(!mk);

	mk->mod = THIS_MODULE;
	kobj_set_kset_s(mk, module_subsys);
	kobject_set_name(&mk->kobj, name);
	kobject_init(&mk->kobj);
	ret = kobject_add(&mk->kobj);
	BUG_ON(ret < 0);
	param_sysfs_setup(mk, kparam, num_params, name_skip);
	kobject_uevent(&mk->kobj, KOBJ_ADD);
}

/*
 * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 *
 * Add module_parameters to sysfs for "modules" built into the kernel.
 *
 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 * "parameter" name is stored behind a dot in kernel_param->name. So,
 * extract the "module" name for all built-in kernel_param-eters,
 * and for all who have the same, call kernel_param_sysfs_setup.
 */
static void __init param_sysfs_builtin(void)
{
	struct kernel_param *kp, *kp_begin = NULL;
	unsigned int i, name_len, count = 0;
	char modname[MAX_KBUILD_MODNAME + 1] = "";

	for (i=0; i < __stop___param - __start___param; i++) {
		char *dot;

		kp = &__start___param[i];

		/* We do not handle args without periods. */
		dot = memchr(kp->name, '.', MAX_KBUILD_MODNAME);
		if (!dot) {
			DEBUGP("couldn't find period in %s\n", kp->name);
			continue;
		}
		name_len = dot - kp->name;

 		/* new kbuild_modname? */
		if (strlen(modname) != name_len
		    || strncmp(modname, kp->name, name_len) != 0) {
			/* add a new kobject for previous kernel_params. */
			if (count)
				kernel_param_sysfs_setup(modname,
							 kp_begin,
							 count,
							 strlen(modname)+1);

			strncpy(modname, kp->name, name_len);
			modname[name_len] = '\0';
			count = 0;
			kp_begin = kp;
		}
		count++;
	}

	/* last kernel_params need to be registered as well */
	if (count)
		kernel_param_sysfs_setup(modname, kp_begin, count,
					 strlen(modname)+1);
}


/* module-related sysfs stuff */
#ifdef CONFIG_SYSFS

#define to_module_attr(n) container_of(n, struct module_attribute, attr);
#define to_module_kobject(n) container_of(n, struct module_kobject, kobj);

static ssize_t module_attr_show(struct kobject *kobj,
				struct attribute *attr,
				char *buf)
{
	struct module_attribute *attribute;
	struct module_kobject *mk;
	int ret;

	attribute = to_module_attr(attr);
	mk = to_module_kobject(kobj);

	if (!attribute->show)
		return -EIO;

	ret = attribute->show(attribute, mk->mod, buf);

	return ret;
}

static ssize_t module_attr_store(struct kobject *kobj,
				struct attribute *attr,
				const char *buf, size_t len)
{
	struct module_attribute *attribute;
	struct module_kobject *mk;
	int ret;

	attribute = to_module_attr(attr);
	mk = to_module_kobject(kobj);

	if (!attribute->store)
		return -EIO;

	ret = attribute->store(attribute, mk->mod, buf, len);

	return ret;
}

static struct sysfs_ops module_sysfs_ops = {
	.show = module_attr_show,
	.store = module_attr_store,
};

#else
static struct sysfs_ops module_sysfs_ops = {
	.show = NULL,
	.store = NULL,
};
#endif

static struct kobj_type module_ktype = {
	.sysfs_ops =	&module_sysfs_ops,
};

decl_subsys(module, &module_ktype, NULL);

/*
 * param_sysfs_init - wrapper for built-in params support
 */
static int __init param_sysfs_init(void)
{
	int ret;

	ret = subsystem_register(&module_subsys);
	if (ret < 0) {
		printk(KERN_WARNING "%s (%d): subsystem_register error: %d\n",
			__FILE__, __LINE__, ret);
		return ret;
	}

	param_sysfs_builtin();

	return 0;
}
subsys_initcall(param_sysfs_init);

EXPORT_SYMBOL(param_set_byte);
EXPORT_SYMBOL(param_get_byte);
EXPORT_SYMBOL(param_set_short);
EXPORT_SYMBOL(param_get_short);
EXPORT_SYMBOL(param_set_ushort);
EXPORT_SYMBOL(param_get_ushort);
EXPORT_SYMBOL(param_set_int);
EXPORT_SYMBOL(param_get_int);
EXPORT_SYMBOL(param_set_uint);
EXPORT_SYMBOL(param_get_uint);
EXPORT_SYMBOL(param_set_long);
EXPORT_SYMBOL(param_get_long);
EXPORT_SYMBOL(param_set_ulong);
EXPORT_SYMBOL(param_get_ulong);
EXPORT_SYMBOL(param_set_charp);
EXPORT_SYMBOL(param_get_charp);
EXPORT_SYMBOL(param_set_bool);
EXPORT_SYMBOL(param_get_bool);
EXPORT_SYMBOL(param_set_invbool);
EXPORT_SYMBOL(param_get_invbool);
EXPORT_SYMBOL(param_array_set);
EXPORT_SYMBOL(param_array_get);
EXPORT_SYMBOL(param_set_copystring);
EXPORT_SYMBOL(param_get_string);
OpenPOWER on IntegriCloud