linux/kernel/params.c
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   1/* Helpers for initial module or kernel cmdline parsing
   2   Copyright (C) 2001 Rusty Russell.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17*/
  18#include <linux/kernel.h>
  19#include <linux/string.h>
  20#include <linux/errno.h>
  21#include <linux/module.h>
  22#include <linux/device.h>
  23#include <linux/err.h>
  24#include <linux/slab.h>
  25#include <linux/ctype.h>
  26
  27/* Protects all parameters, and incidentally kmalloced_param list. */
  28static DEFINE_MUTEX(param_lock);
  29
  30/* This just allows us to keep track of which parameters are kmalloced. */
  31struct kmalloced_param {
  32        struct list_head list;
  33        char val[];
  34};
  35static LIST_HEAD(kmalloced_params);
  36
  37static void *kmalloc_parameter(unsigned int size)
  38{
  39        struct kmalloced_param *p;
  40
  41        p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  42        if (!p)
  43                return NULL;
  44
  45        list_add(&p->list, &kmalloced_params);
  46        return p->val;
  47}
  48
  49/* Does nothing if parameter wasn't kmalloced above. */
  50static void maybe_kfree_parameter(void *param)
  51{
  52        struct kmalloced_param *p;
  53
  54        list_for_each_entry(p, &kmalloced_params, list) {
  55                if (p->val == param) {
  56                        list_del(&p->list);
  57                        kfree(p);
  58                        break;
  59                }
  60        }
  61}
  62
  63static char dash2underscore(char c)
  64{
  65        if (c == '-')
  66                return '_';
  67        return c;
  68}
  69
  70bool parameqn(const char *a, const char *b, size_t n)
  71{
  72        size_t i;
  73
  74        for (i = 0; i < n; i++) {
  75                if (dash2underscore(a[i]) != dash2underscore(b[i]))
  76                        return false;
  77        }
  78        return true;
  79}
  80
  81bool parameq(const char *a, const char *b)
  82{
  83        return parameqn(a, b, strlen(a)+1);
  84}
  85
  86static int parse_one(char *param,
  87                     char *val,
  88                     const char *doing,
  89                     const struct kernel_param *params,
  90                     unsigned num_params,
  91                     s16 min_level,
  92                     s16 max_level,
  93                     int (*handle_unknown)(char *param, char *val,
  94                                     const char *doing))
  95{
  96        unsigned int i;
  97        int err;
  98
  99        /* Find parameter */
 100        for (i = 0; i < num_params; i++) {
 101                if (parameq(param, params[i].name)) {
 102                        if (params[i].level < min_level
 103                            || params[i].level > max_level)
 104                                return 0;
 105                        /* No one handled NULL, so do it here. */
 106                        if (!val &&
 107                            !(params[i].ops->flags & KERNEL_PARAM_FL_NOARG))
 108                                return -EINVAL;
 109                        pr_debug("handling %s with %p\n", param,
 110                                params[i].ops->set);
 111                        mutex_lock(&param_lock);
 112                        err = params[i].ops->set(val, &params[i]);
 113                        mutex_unlock(&param_lock);
 114                        return err;
 115                }
 116        }
 117
 118        if (handle_unknown) {
 119                pr_debug("doing %s: %s='%s'\n", doing, param, val);
 120                return handle_unknown(param, val, doing);
 121        }
 122
 123        pr_debug("Unknown argument '%s'\n", param);
 124        return -ENOENT;
 125}
 126
 127/* You can use " around spaces, but can't escape ". */
 128/* Hyphens and underscores equivalent in parameter names. */
 129static char *next_arg(char *args, char **param, char **val)
 130{
 131        unsigned int i, equals = 0;
 132        int in_quote = 0, quoted = 0;
 133        char *next;
 134
 135        if (*args == '"') {
 136                args++;
 137                in_quote = 1;
 138                quoted = 1;
 139        }
 140
 141        for (i = 0; args[i]; i++) {
 142                if (isspace(args[i]) && !in_quote)
 143                        break;
 144                if (equals == 0) {
 145                        if (args[i] == '=')
 146                                equals = i;
 147                }
 148                if (args[i] == '"')
 149                        in_quote = !in_quote;
 150        }
 151
 152        *param = args;
 153        if (!equals)
 154                *val = NULL;
 155        else {
 156                args[equals] = '\0';
 157                *val = args + equals + 1;
 158
 159                /* Don't include quotes in value. */
 160                if (**val == '"') {
 161                        (*val)++;
 162                        if (args[i-1] == '"')
 163                                args[i-1] = '\0';
 164                }
 165                if (quoted && args[i-1] == '"')
 166                        args[i-1] = '\0';
 167        }
 168
 169        if (args[i]) {
 170                args[i] = '\0';
 171                next = args + i + 1;
 172        } else
 173                next = args + i;
 174
 175        /* Chew up trailing spaces. */
 176        return skip_spaces(next);
 177}
 178
 179/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 180int parse_args(const char *doing,
 181               char *args,
 182               const struct kernel_param *params,
 183               unsigned num,
 184               s16 min_level,
 185               s16 max_level,
 186               int (*unknown)(char *param, char *val, const char *doing))
 187{
 188        char *param, *val;
 189
 190        /* Chew leading spaces */
 191        args = skip_spaces(args);
 192
 193        if (*args)
 194                pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 195
 196        while (*args) {
 197                int ret;
 198                int irq_was_disabled;
 199
 200                args = next_arg(args, &param, &val);
 201                irq_was_disabled = irqs_disabled();
 202                ret = parse_one(param, val, doing, params, num,
 203                                min_level, max_level, unknown);
 204                if (irq_was_disabled && !irqs_disabled())
 205                        pr_warn("%s: option '%s' enabled irq's!\n",
 206                                doing, param);
 207
 208                switch (ret) {
 209                case -ENOENT:
 210                        pr_err("%s: Unknown parameter `%s'\n", doing, param);
 211                        return ret;
 212                case -ENOSPC:
 213                        pr_err("%s: `%s' too large for parameter `%s'\n",
 214                               doing, val ?: "", param);
 215                        return ret;
 216                case 0:
 217                        break;
 218                default:
 219                        pr_err("%s: `%s' invalid for parameter `%s'\n",
 220                               doing, val ?: "", param);
 221                        return ret;
 222                }
 223        }
 224
 225        /* All parsed OK. */
 226        return 0;
 227}
 228
 229/* Lazy bastard, eh? */
 230#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 231        int param_set_##name(const char *val, const struct kernel_param *kp) \
 232        {                                                               \
 233                tmptype l;                                              \
 234                int ret;                                                \
 235                                                                        \
 236                ret = strtolfn(val, 0, &l);                             \
 237                if (ret < 0 || ((type)l != l))                          \
 238                        return ret < 0 ? ret : -EINVAL;                 \
 239                *((type *)kp->arg) = l;                                 \
 240                return 0;                                               \
 241        }                                                               \
 242        int param_get_##name(char *buffer, const struct kernel_param *kp) \
 243        {                                                               \
 244                return scnprintf(buffer, PAGE_SIZE, format,             \
 245                                *((type *)kp->arg));                    \
 246        }                                                               \
 247        struct kernel_param_ops param_ops_##name = {                    \
 248                .set = param_set_##name,                                \
 249                .get = param_get_##name,                                \
 250        };                                                              \
 251        EXPORT_SYMBOL(param_set_##name);                                \
 252        EXPORT_SYMBOL(param_get_##name);                                \
 253        EXPORT_SYMBOL(param_ops_##name)
 254
 255
 256STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", unsigned long, kstrtoul);
 257STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtol);
 258STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, kstrtoul);
 259STANDARD_PARAM_DEF(int, int, "%i", long, kstrtol);
 260STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, kstrtoul);
 261STANDARD_PARAM_DEF(long, long, "%li", long, kstrtol);
 262STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, kstrtoul);
 263
 264int param_set_charp(const char *val, const struct kernel_param *kp)
 265{
 266        if (strlen(val) > 1024) {
 267                pr_err("%s: string parameter too long\n", kp->name);
 268                return -ENOSPC;
 269        }
 270
 271        maybe_kfree_parameter(*(char **)kp->arg);
 272
 273        /* This is a hack.  We can't kmalloc in early boot, and we
 274         * don't need to; this mangled commandline is preserved. */
 275        if (slab_is_available()) {
 276                *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 277                if (!*(char **)kp->arg)
 278                        return -ENOMEM;
 279                strcpy(*(char **)kp->arg, val);
 280        } else
 281                *(const char **)kp->arg = val;
 282
 283        return 0;
 284}
 285EXPORT_SYMBOL(param_set_charp);
 286
 287int param_get_charp(char *buffer, const struct kernel_param *kp)
 288{
 289        return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 290}
 291EXPORT_SYMBOL(param_get_charp);
 292
 293static void param_free_charp(void *arg)
 294{
 295        maybe_kfree_parameter(*((char **)arg));
 296}
 297
 298struct kernel_param_ops param_ops_charp = {
 299        .set = param_set_charp,
 300        .get = param_get_charp,
 301        .free = param_free_charp,
 302};
 303EXPORT_SYMBOL(param_ops_charp);
 304
 305/* Actually could be a bool or an int, for historical reasons. */
 306int param_set_bool(const char *val, const struct kernel_param *kp)
 307{
 308        /* No equals means "set"... */
 309        if (!val) val = "1";
 310
 311        /* One of =[yYnN01] */
 312        return strtobool(val, kp->arg);
 313}
 314EXPORT_SYMBOL(param_set_bool);
 315
 316int param_get_bool(char *buffer, const struct kernel_param *kp)
 317{
 318        /* Y and N chosen as being relatively non-coder friendly */
 319        return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 320}
 321EXPORT_SYMBOL(param_get_bool);
 322
 323struct kernel_param_ops param_ops_bool = {
 324        .flags = KERNEL_PARAM_FL_NOARG,
 325        .set = param_set_bool,
 326        .get = param_get_bool,
 327};
 328EXPORT_SYMBOL(param_ops_bool);
 329
 330/* This one must be bool. */
 331int param_set_invbool(const char *val, const struct kernel_param *kp)
 332{
 333        int ret;
 334        bool boolval;
 335        struct kernel_param dummy;
 336
 337        dummy.arg = &boolval;
 338        ret = param_set_bool(val, &dummy);
 339        if (ret == 0)
 340                *(bool *)kp->arg = !boolval;
 341        return ret;
 342}
 343EXPORT_SYMBOL(param_set_invbool);
 344
 345int param_get_invbool(char *buffer, const struct kernel_param *kp)
 346{
 347        return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 348}
 349EXPORT_SYMBOL(param_get_invbool);
 350
 351struct kernel_param_ops param_ops_invbool = {
 352        .set = param_set_invbool,
 353        .get = param_get_invbool,
 354};
 355EXPORT_SYMBOL(param_ops_invbool);
 356
 357int param_set_bint(const char *val, const struct kernel_param *kp)
 358{
 359        struct kernel_param boolkp;
 360        bool v;
 361        int ret;
 362
 363        /* Match bool exactly, by re-using it. */
 364        boolkp = *kp;
 365        boolkp.arg = &v;
 366
 367        ret = param_set_bool(val, &boolkp);
 368        if (ret == 0)
 369                *(int *)kp->arg = v;
 370        return ret;
 371}
 372EXPORT_SYMBOL(param_set_bint);
 373
 374struct kernel_param_ops param_ops_bint = {
 375        .flags = KERNEL_PARAM_FL_NOARG,
 376        .set = param_set_bint,
 377        .get = param_get_int,
 378};
 379EXPORT_SYMBOL(param_ops_bint);
 380
 381/* We break the rule and mangle the string. */
 382static int param_array(const char *name,
 383                       const char *val,
 384                       unsigned int min, unsigned int max,
 385                       void *elem, int elemsize,
 386                       int (*set)(const char *, const struct kernel_param *kp),
 387                       s16 level,
 388                       unsigned int *num)
 389{
 390        int ret;
 391        struct kernel_param kp;
 392        char save;
 393
 394        /* Get the name right for errors. */
 395        kp.name = name;
 396        kp.arg = elem;
 397        kp.level = level;
 398
 399        *num = 0;
 400        /* We expect a comma-separated list of values. */
 401        do {
 402                int len;
 403
 404                if (*num == max) {
 405                        pr_err("%s: can only take %i arguments\n", name, max);
 406                        return -EINVAL;
 407                }
 408                len = strcspn(val, ",");
 409
 410                /* nul-terminate and parse */
 411                save = val[len];
 412                ((char *)val)[len] = '\0';
 413                BUG_ON(!mutex_is_locked(&param_lock));
 414                ret = set(val, &kp);
 415
 416                if (ret != 0)
 417                        return ret;
 418                kp.arg += elemsize;
 419                val += len+1;
 420                (*num)++;
 421        } while (save == ',');
 422
 423        if (*num < min) {
 424                pr_err("%s: needs at least %i arguments\n", name, min);
 425                return -EINVAL;
 426        }
 427        return 0;
 428}
 429
 430static int param_array_set(const char *val, const struct kernel_param *kp)
 431{
 432        const struct kparam_array *arr = kp->arr;
 433        unsigned int temp_num;
 434
 435        return param_array(kp->name, val, 1, arr->max, arr->elem,
 436                           arr->elemsize, arr->ops->set, kp->level,
 437                           arr->num ?: &temp_num);
 438}
 439
 440static int param_array_get(char *buffer, const struct kernel_param *kp)
 441{
 442        int i, off, ret;
 443        const struct kparam_array *arr = kp->arr;
 444        struct kernel_param p;
 445
 446        p = *kp;
 447        for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 448                if (i)
 449                        buffer[off++] = ',';
 450                p.arg = arr->elem + arr->elemsize * i;
 451                BUG_ON(!mutex_is_locked(&param_lock));
 452                ret = arr->ops->get(buffer + off, &p);
 453                if (ret < 0)
 454                        return ret;
 455                off += ret;
 456        }
 457        buffer[off] = '\0';
 458        return off;
 459}
 460
 461static void param_array_free(void *arg)
 462{
 463        unsigned int i;
 464        const struct kparam_array *arr = arg;
 465
 466        if (arr->ops->free)
 467                for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 468                        arr->ops->free(arr->elem + arr->elemsize * i);
 469}
 470
 471struct kernel_param_ops param_array_ops = {
 472        .set = param_array_set,
 473        .get = param_array_get,
 474        .free = param_array_free,
 475};
 476EXPORT_SYMBOL(param_array_ops);
 477
 478int param_set_copystring(const char *val, const struct kernel_param *kp)
 479{
 480        const struct kparam_string *kps = kp->str;
 481
 482        if (strlen(val)+1 > kps->maxlen) {
 483                pr_err("%s: string doesn't fit in %u chars.\n",
 484                       kp->name, kps->maxlen-1);
 485                return -ENOSPC;
 486        }
 487        strcpy(kps->string, val);
 488        return 0;
 489}
 490EXPORT_SYMBOL(param_set_copystring);
 491
 492int param_get_string(char *buffer, const struct kernel_param *kp)
 493{
 494        const struct kparam_string *kps = kp->str;
 495        return strlcpy(buffer, kps->string, kps->maxlen);
 496}
 497EXPORT_SYMBOL(param_get_string);
 498
 499struct kernel_param_ops param_ops_string = {
 500        .set = param_set_copystring,
 501        .get = param_get_string,
 502};
 503EXPORT_SYMBOL(param_ops_string);
 504
 505/* sysfs output in /sys/modules/XYZ/parameters/ */
 506#define to_module_attr(n) container_of(n, struct module_attribute, attr)
 507#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 508
 509extern struct kernel_param __start___param[], __stop___param[];
 510
 511struct param_attribute
 512{
 513        struct module_attribute mattr;
 514        const struct kernel_param *param;
 515};
 516
 517struct module_param_attrs
 518{
 519        unsigned int num;
 520        struct attribute_group grp;
 521        struct param_attribute attrs[0];
 522};
 523
 524#ifdef CONFIG_SYSFS
 525#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 526
 527static ssize_t param_attr_show(struct module_attribute *mattr,
 528                               struct module_kobject *mk, char *buf)
 529{
 530        int count;
 531        struct param_attribute *attribute = to_param_attr(mattr);
 532
 533        if (!attribute->param->ops->get)
 534                return -EPERM;
 535
 536        mutex_lock(&param_lock);
 537        count = attribute->param->ops->get(buf, attribute->param);
 538        mutex_unlock(&param_lock);
 539        if (count > 0) {
 540                strcat(buf, "\n");
 541                ++count;
 542        }
 543        return count;
 544}
 545
 546/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 547static ssize_t param_attr_store(struct module_attribute *mattr,
 548                                struct module_kobject *km,
 549                                const char *buf, size_t len)
 550{
 551        int err;
 552        struct param_attribute *attribute = to_param_attr(mattr);
 553
 554        if (!attribute->param->ops->set)
 555                return -EPERM;
 556
 557        mutex_lock(&param_lock);
 558        err = attribute->param->ops->set(buf, attribute->param);
 559        mutex_unlock(&param_lock);
 560        if (!err)
 561                return len;
 562        return err;
 563}
 564#endif
 565
 566#ifdef CONFIG_MODULES
 567#define __modinit
 568#else
 569#define __modinit __init
 570#endif
 571
 572#ifdef CONFIG_SYSFS
 573void __kernel_param_lock(void)
 574{
 575        mutex_lock(&param_lock);
 576}
 577EXPORT_SYMBOL(__kernel_param_lock);
 578
 579void __kernel_param_unlock(void)
 580{
 581        mutex_unlock(&param_lock);
 582}
 583EXPORT_SYMBOL(__kernel_param_unlock);
 584
 585/*
 586 * add_sysfs_param - add a parameter to sysfs
 587 * @mk: struct module_kobject
 588 * @kparam: the actual parameter definition to add to sysfs
 589 * @name: name of parameter
 590 *
 591 * Create a kobject if for a (per-module) parameter if mp NULL, and
 592 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 593 * if there's an error.
 594 */
 595static __modinit int add_sysfs_param(struct module_kobject *mk,
 596                                     const struct kernel_param *kp,
 597                                     const char *name)
 598{
 599        struct module_param_attrs *new;
 600        struct attribute **attrs;
 601        int err, num;
 602
 603        /* We don't bother calling this with invisible parameters. */
 604        BUG_ON(!kp->perm);
 605
 606        if (!mk->mp) {
 607                num = 0;
 608                attrs = NULL;
 609        } else {
 610                num = mk->mp->num;
 611                attrs = mk->mp->grp.attrs;
 612        }
 613
 614        /* Enlarge. */
 615        new = krealloc(mk->mp,
 616                       sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 617                       GFP_KERNEL);
 618        if (!new) {
 619                kfree(attrs);
 620                err = -ENOMEM;
 621                goto fail;
 622        }
 623        /* Despite looking like the typical realloc() bug, this is safe.
 624         * We *want* the old 'attrs' to be freed either way, and we'll store
 625         * the new one in the success case. */
 626        attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 627        if (!attrs) {
 628                err = -ENOMEM;
 629                goto fail_free_new;
 630        }
 631
 632        /* Sysfs wants everything zeroed. */
 633        memset(new, 0, sizeof(*new));
 634        memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 635        memset(&attrs[num], 0, sizeof(attrs[num]));
 636        new->grp.name = "parameters";
 637        new->grp.attrs = attrs;
 638
 639        /* Tack new one on the end. */
 640        sysfs_attr_init(&new->attrs[num].mattr.attr);
 641        new->attrs[num].param = kp;
 642        new->attrs[num].mattr.show = param_attr_show;
 643        new->attrs[num].mattr.store = param_attr_store;
 644        new->attrs[num].mattr.attr.name = (char *)name;
 645        new->attrs[num].mattr.attr.mode = kp->perm;
 646        new->num = num+1;
 647
 648        /* Fix up all the pointers, since krealloc can move us */
 649        for (num = 0; num < new->num; num++)
 650                new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 651        new->grp.attrs[num] = NULL;
 652
 653        mk->mp = new;
 654        return 0;
 655
 656fail_free_new:
 657        kfree(new);
 658fail:
 659        mk->mp = NULL;
 660        return err;
 661}
 662
 663#ifdef CONFIG_MODULES
 664static void free_module_param_attrs(struct module_kobject *mk)
 665{
 666        kfree(mk->mp->grp.attrs);
 667        kfree(mk->mp);
 668        mk->mp = NULL;
 669}
 670
 671/*
 672 * module_param_sysfs_setup - setup sysfs support for one module
 673 * @mod: module
 674 * @kparam: module parameters (array)
 675 * @num_params: number of module parameters
 676 *
 677 * Adds sysfs entries for module parameters under
 678 * /sys/module/[mod->name]/parameters/
 679 */
 680int module_param_sysfs_setup(struct module *mod,
 681                             const struct kernel_param *kparam,
 682                             unsigned int num_params)
 683{
 684        int i, err;
 685        bool params = false;
 686
 687        for (i = 0; i < num_params; i++) {
 688                if (kparam[i].perm == 0)
 689                        continue;
 690                err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 691                if (err)
 692                        return err;
 693                params = true;
 694        }
 695
 696        if (!params)
 697                return 0;
 698
 699        /* Create the param group. */
 700        err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 701        if (err)
 702                free_module_param_attrs(&mod->mkobj);
 703        return err;
 704}
 705
 706/*
 707 * module_param_sysfs_remove - remove sysfs support for one module
 708 * @mod: module
 709 *
 710 * Remove sysfs entries for module parameters and the corresponding
 711 * kobject.
 712 */
 713void module_param_sysfs_remove(struct module *mod)
 714{
 715        if (mod->mkobj.mp) {
 716                sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 717                /* We are positive that no one is using any param
 718                 * attrs at this point.  Deallocate immediately. */
 719                free_module_param_attrs(&mod->mkobj);
 720        }
 721}
 722#endif
 723
 724void destroy_params(const struct kernel_param *params, unsigned num)
 725{
 726        unsigned int i;
 727
 728        for (i = 0; i < num; i++)
 729                if (params[i].ops->free)
 730                        params[i].ops->free(params[i].arg);
 731}
 732
 733static struct module_kobject * __init locate_module_kobject(const char *name)
 734{
 735        struct module_kobject *mk;
 736        struct kobject *kobj;
 737        int err;
 738
 739        kobj = kset_find_obj(module_kset, name);
 740        if (kobj) {
 741                mk = to_module_kobject(kobj);
 742        } else {
 743                mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 744                BUG_ON(!mk);
 745
 746                mk->mod = THIS_MODULE;
 747                mk->kobj.kset = module_kset;
 748                err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 749                                           "%s", name);
 750#ifdef CONFIG_MODULES
 751                if (!err)
 752                        err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 753#endif
 754                if (err) {
 755                        kobject_put(&mk->kobj);
 756                        pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 757                                name, err);
 758                        return NULL;
 759                }
 760
 761                /* So that we hold reference in both cases. */
 762                kobject_get(&mk->kobj);
 763        }
 764
 765        return mk;
 766}
 767
 768static void __init kernel_add_sysfs_param(const char *name,
 769                                          struct kernel_param *kparam,
 770                                          unsigned int name_skip)
 771{
 772        struct module_kobject *mk;
 773        int err;
 774
 775        mk = locate_module_kobject(name);
 776        if (!mk)
 777                return;
 778
 779        /* We need to remove old parameters before adding more. */
 780        if (mk->mp)
 781                sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 782
 783        /* These should not fail at boot. */
 784        err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 785        BUG_ON(err);
 786        err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 787        BUG_ON(err);
 788        kobject_uevent(&mk->kobj, KOBJ_ADD);
 789        kobject_put(&mk->kobj);
 790}
 791
 792/*
 793 * param_sysfs_builtin - add sysfs parameters for built-in modules
 794 *
 795 * Add module_parameters to sysfs for "modules" built into the kernel.
 796 *
 797 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 798 * "parameter" name is stored behind a dot in kernel_param->name. So,
 799 * extract the "module" name for all built-in kernel_param-eters,
 800 * and for all who have the same, call kernel_add_sysfs_param.
 801 */
 802static void __init param_sysfs_builtin(void)
 803{
 804        struct kernel_param *kp;
 805        unsigned int name_len;
 806        char modname[MODULE_NAME_LEN];
 807
 808        for (kp = __start___param; kp < __stop___param; kp++) {
 809                char *dot;
 810
 811                if (kp->perm == 0)
 812                        continue;
 813
 814                dot = strchr(kp->name, '.');
 815                if (!dot) {
 816                        /* This happens for core_param() */
 817                        strcpy(modname, "kernel");
 818                        name_len = 0;
 819                } else {
 820                        name_len = dot - kp->name + 1;
 821                        strlcpy(modname, kp->name, name_len);
 822                }
 823                kernel_add_sysfs_param(modname, kp, name_len);
 824        }
 825}
 826
 827ssize_t __modver_version_show(struct module_attribute *mattr,
 828                              struct module_kobject *mk, char *buf)
 829{
 830        struct module_version_attribute *vattr =
 831                container_of(mattr, struct module_version_attribute, mattr);
 832
 833        return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 834}
 835
 836extern const struct module_version_attribute *__start___modver[];
 837extern const struct module_version_attribute *__stop___modver[];
 838
 839static void __init version_sysfs_builtin(void)
 840{
 841        const struct module_version_attribute **p;
 842        struct module_kobject *mk;
 843        int err;
 844
 845        for (p = __start___modver; p < __stop___modver; p++) {
 846                const struct module_version_attribute *vattr = *p;
 847
 848                mk = locate_module_kobject(vattr->module_name);
 849                if (mk) {
 850                        err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 851                        kobject_uevent(&mk->kobj, KOBJ_ADD);
 852                        kobject_put(&mk->kobj);
 853                }
 854        }
 855}
 856
 857/* module-related sysfs stuff */
 858
 859static ssize_t module_attr_show(struct kobject *kobj,
 860                                struct attribute *attr,
 861                                char *buf)
 862{
 863        struct module_attribute *attribute;
 864        struct module_kobject *mk;
 865        int ret;
 866
 867        attribute = to_module_attr(attr);
 868        mk = to_module_kobject(kobj);
 869
 870        if (!attribute->show)
 871                return -EIO;
 872
 873        ret = attribute->show(attribute, mk, buf);
 874
 875        return ret;
 876}
 877
 878static ssize_t module_attr_store(struct kobject *kobj,
 879                                struct attribute *attr,
 880                                const char *buf, size_t len)
 881{
 882        struct module_attribute *attribute;
 883        struct module_kobject *mk;
 884        int ret;
 885
 886        attribute = to_module_attr(attr);
 887        mk = to_module_kobject(kobj);
 888
 889        if (!attribute->store)
 890                return -EIO;
 891
 892        ret = attribute->store(attribute, mk, buf, len);
 893
 894        return ret;
 895}
 896
 897static const struct sysfs_ops module_sysfs_ops = {
 898        .show = module_attr_show,
 899        .store = module_attr_store,
 900};
 901
 902static int uevent_filter(struct kset *kset, struct kobject *kobj)
 903{
 904        struct kobj_type *ktype = get_ktype(kobj);
 905
 906        if (ktype == &module_ktype)
 907                return 1;
 908        return 0;
 909}
 910
 911static const struct kset_uevent_ops module_uevent_ops = {
 912        .filter = uevent_filter,
 913};
 914
 915struct kset *module_kset;
 916int module_sysfs_initialized;
 917
 918static void module_kobj_release(struct kobject *kobj)
 919{
 920        struct module_kobject *mk = to_module_kobject(kobj);
 921        complete(mk->kobj_completion);
 922}
 923
 924struct kobj_type module_ktype = {
 925        .release   =    module_kobj_release,
 926        .sysfs_ops =    &module_sysfs_ops,
 927};
 928
 929/*
 930 * param_sysfs_init - wrapper for built-in params support
 931 */
 932static int __init param_sysfs_init(void)
 933{
 934        module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 935        if (!module_kset) {
 936                printk(KERN_WARNING "%s (%d): error creating kset\n",
 937                        __FILE__, __LINE__);
 938                return -ENOMEM;
 939        }
 940        module_sysfs_initialized = 1;
 941
 942        version_sysfs_builtin();
 943        param_sysfs_builtin();
 944
 945        return 0;
 946}
 947subsys_initcall(param_sysfs_init);
 948
 949#endif /* CONFIG_SYSFS */
 950
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