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 && params[i].ops->set != param_set_bool
 107                            && params[i].ops->set != param_set_bint)
 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 sprintf(buffer, format, *((type *)kp->arg));     \
 245        }                                                               \
 246        struct kernel_param_ops param_ops_##name = {                    \
 247                .set = param_set_##name,                                \
 248                .get = param_get_##name,                                \
 249        };                                                              \
 250        EXPORT_SYMBOL(param_set_##name);                                \
 251        EXPORT_SYMBOL(param_get_##name);                                \
 252        EXPORT_SYMBOL(param_ops_##name)
 253
 254
 255STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 256STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 257STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 258STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 259STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 260STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 261STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 262
 263int param_set_charp(const char *val, const struct kernel_param *kp)
 264{
 265        if (strlen(val) > 1024) {
 266                pr_err("%s: string parameter too long\n", kp->name);
 267                return -ENOSPC;
 268        }
 269
 270        maybe_kfree_parameter(*(char **)kp->arg);
 271
 272        /* This is a hack.  We can't kmalloc in early boot, and we
 273         * don't need to; this mangled commandline is preserved. */
 274        if (slab_is_available()) {
 275                *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 276                if (!*(char **)kp->arg)
 277                        return -ENOMEM;
 278                strcpy(*(char **)kp->arg, val);
 279        } else
 280                *(const char **)kp->arg = val;
 281
 282        return 0;
 283}
 284EXPORT_SYMBOL(param_set_charp);
 285
 286int param_get_charp(char *buffer, const struct kernel_param *kp)
 287{
 288        return sprintf(buffer, "%s", *((char **)kp->arg));
 289}
 290EXPORT_SYMBOL(param_get_charp);
 291
 292static void param_free_charp(void *arg)
 293{
 294        maybe_kfree_parameter(*((char **)arg));
 295}
 296
 297struct kernel_param_ops param_ops_charp = {
 298        .set = param_set_charp,
 299        .get = param_get_charp,
 300        .free = param_free_charp,
 301};
 302EXPORT_SYMBOL(param_ops_charp);
 303
 304/* Actually could be a bool or an int, for historical reasons. */
 305int param_set_bool(const char *val, const struct kernel_param *kp)
 306{
 307        /* No equals means "set"... */
 308        if (!val) val = "1";
 309
 310        /* One of =[yYnN01] */
 311        return strtobool(val, kp->arg);
 312}
 313EXPORT_SYMBOL(param_set_bool);
 314
 315int param_get_bool(char *buffer, const struct kernel_param *kp)
 316{
 317        /* Y and N chosen as being relatively non-coder friendly */
 318        return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 319}
 320EXPORT_SYMBOL(param_get_bool);
 321
 322struct kernel_param_ops param_ops_bool = {
 323        .set = param_set_bool,
 324        .get = param_get_bool,
 325};
 326EXPORT_SYMBOL(param_ops_bool);
 327
 328/* This one must be bool. */
 329int param_set_invbool(const char *val, const struct kernel_param *kp)
 330{
 331        int ret;
 332        bool boolval;
 333        struct kernel_param dummy;
 334
 335        dummy.arg = &boolval;
 336        ret = param_set_bool(val, &dummy);
 337        if (ret == 0)
 338                *(bool *)kp->arg = !boolval;
 339        return ret;
 340}
 341EXPORT_SYMBOL(param_set_invbool);
 342
 343int param_get_invbool(char *buffer, const struct kernel_param *kp)
 344{
 345        return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 346}
 347EXPORT_SYMBOL(param_get_invbool);
 348
 349struct kernel_param_ops param_ops_invbool = {
 350        .set = param_set_invbool,
 351        .get = param_get_invbool,
 352};
 353EXPORT_SYMBOL(param_ops_invbool);
 354
 355int param_set_bint(const char *val, const struct kernel_param *kp)
 356{
 357        struct kernel_param boolkp;
 358        bool v;
 359        int ret;
 360
 361        /* Match bool exactly, by re-using it. */
 362        boolkp = *kp;
 363        boolkp.arg = &v;
 364
 365        ret = param_set_bool(val, &boolkp);
 366        if (ret == 0)
 367                *(int *)kp->arg = v;
 368        return ret;
 369}
 370EXPORT_SYMBOL(param_set_bint);
 371
 372struct kernel_param_ops param_ops_bint = {
 373        .set = param_set_bint,
 374        .get = param_get_int,
 375};
 376EXPORT_SYMBOL(param_ops_bint);
 377
 378/* We break the rule and mangle the string. */
 379static int param_array(const char *name,
 380                       const char *val,
 381                       unsigned int min, unsigned int max,
 382                       void *elem, int elemsize,
 383                       int (*set)(const char *, const struct kernel_param *kp),
 384                       s16 level,
 385                       unsigned int *num)
 386{
 387        int ret;
 388        struct kernel_param kp;
 389        char save;
 390
 391        /* Get the name right for errors. */
 392        kp.name = name;
 393        kp.arg = elem;
 394        kp.level = level;
 395
 396        *num = 0;
 397        /* We expect a comma-separated list of values. */
 398        do {
 399                int len;
 400
 401                if (*num == max) {
 402                        pr_err("%s: can only take %i arguments\n", name, max);
 403                        return -EINVAL;
 404                }
 405                len = strcspn(val, ",");
 406
 407                /* nul-terminate and parse */
 408                save = val[len];
 409                ((char *)val)[len] = '\0';
 410                BUG_ON(!mutex_is_locked(&param_lock));
 411                ret = set(val, &kp);
 412
 413                if (ret != 0)
 414                        return ret;
 415                kp.arg += elemsize;
 416                val += len+1;
 417                (*num)++;
 418        } while (save == ',');
 419
 420        if (*num < min) {
 421                pr_err("%s: needs at least %i arguments\n", name, min);
 422                return -EINVAL;
 423        }
 424        return 0;
 425}
 426
 427static int param_array_set(const char *val, const struct kernel_param *kp)
 428{
 429        const struct kparam_array *arr = kp->arr;
 430        unsigned int temp_num;
 431
 432        return param_array(kp->name, val, 1, arr->max, arr->elem,
 433                           arr->elemsize, arr->ops->set, kp->level,
 434                           arr->num ?: &temp_num);
 435}
 436
 437static int param_array_get(char *buffer, const struct kernel_param *kp)
 438{
 439        int i, off, ret;
 440        const struct kparam_array *arr = kp->arr;
 441        struct kernel_param p;
 442
 443        p = *kp;
 444        for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 445                if (i)
 446                        buffer[off++] = ',';
 447                p.arg = arr->elem + arr->elemsize * i;
 448                BUG_ON(!mutex_is_locked(&param_lock));
 449                ret = arr->ops->get(buffer + off, &p);
 450                if (ret < 0)
 451                        return ret;
 452                off += ret;
 453        }
 454        buffer[off] = '\0';
 455        return off;
 456}
 457
 458static void param_array_free(void *arg)
 459{
 460        unsigned int i;
 461        const struct kparam_array *arr = arg;
 462
 463        if (arr->ops->free)
 464                for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 465                        arr->ops->free(arr->elem + arr->elemsize * i);
 466}
 467
 468struct kernel_param_ops param_array_ops = {
 469        .set = param_array_set,
 470        .get = param_array_get,
 471        .free = param_array_free,
 472};
 473EXPORT_SYMBOL(param_array_ops);
 474
 475int param_set_copystring(const char *val, const struct kernel_param *kp)
 476{
 477        const struct kparam_string *kps = kp->str;
 478
 479        if (strlen(val)+1 > kps->maxlen) {
 480                pr_err("%s: string doesn't fit in %u chars.\n",
 481                       kp->name, kps->maxlen-1);
 482                return -ENOSPC;
 483        }
 484        strcpy(kps->string, val);
 485        return 0;
 486}
 487EXPORT_SYMBOL(param_set_copystring);
 488
 489int param_get_string(char *buffer, const struct kernel_param *kp)
 490{
 491        const struct kparam_string *kps = kp->str;
 492        return strlcpy(buffer, kps->string, kps->maxlen);
 493}
 494EXPORT_SYMBOL(param_get_string);
 495
 496struct kernel_param_ops param_ops_string = {
 497        .set = param_set_copystring,
 498        .get = param_get_string,
 499};
 500EXPORT_SYMBOL(param_ops_string);
 501
 502/* sysfs output in /sys/modules/XYZ/parameters/ */
 503#define to_module_attr(n) container_of(n, struct module_attribute, attr)
 504#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 505
 506extern struct kernel_param __start___param[], __stop___param[];
 507
 508struct param_attribute
 509{
 510        struct module_attribute mattr;
 511        const struct kernel_param *param;
 512};
 513
 514struct module_param_attrs
 515{
 516        unsigned int num;
 517        struct attribute_group grp;
 518        struct param_attribute attrs[0];
 519};
 520
 521#ifdef CONFIG_SYSFS
 522#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 523
 524static ssize_t param_attr_show(struct module_attribute *mattr,
 525                               struct module_kobject *mk, char *buf)
 526{
 527        int count;
 528        struct param_attribute *attribute = to_param_attr(mattr);
 529
 530        if (!attribute->param->ops->get)
 531                return -EPERM;
 532
 533        mutex_lock(&param_lock);
 534        count = attribute->param->ops->get(buf, attribute->param);
 535        mutex_unlock(&param_lock);
 536        if (count > 0) {
 537                strcat(buf, "\n");
 538                ++count;
 539        }
 540        return count;
 541}
 542
 543/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 544static ssize_t param_attr_store(struct module_attribute *mattr,
 545                                struct module_kobject *km,
 546                                const char *buf, size_t len)
 547{
 548        int err;
 549        struct param_attribute *attribute = to_param_attr(mattr);
 550
 551        if (!attribute->param->ops->set)
 552                return -EPERM;
 553
 554        mutex_lock(&param_lock);
 555        err = attribute->param->ops->set(buf, attribute->param);
 556        mutex_unlock(&param_lock);
 557        if (!err)
 558                return len;
 559        return err;
 560}
 561#endif
 562
 563#ifdef CONFIG_MODULES
 564#define __modinit
 565#else
 566#define __modinit __init
 567#endif
 568
 569#ifdef CONFIG_SYSFS
 570void __kernel_param_lock(void)
 571{
 572        mutex_lock(&param_lock);
 573}
 574EXPORT_SYMBOL(__kernel_param_lock);
 575
 576void __kernel_param_unlock(void)
 577{
 578        mutex_unlock(&param_lock);
 579}
 580EXPORT_SYMBOL(__kernel_param_unlock);
 581
 582/*
 583 * add_sysfs_param - add a parameter to sysfs
 584 * @mk: struct module_kobject
 585 * @kparam: the actual parameter definition to add to sysfs
 586 * @name: name of parameter
 587 *
 588 * Create a kobject if for a (per-module) parameter if mp NULL, and
 589 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 590 * if there's an error.
 591 */
 592static __modinit int add_sysfs_param(struct module_kobject *mk,
 593                                     const struct kernel_param *kp,
 594                                     const char *name)
 595{
 596        struct module_param_attrs *new;
 597        struct attribute **attrs;
 598        int err, num;
 599
 600        /* We don't bother calling this with invisible parameters. */
 601        BUG_ON(!kp->perm);
 602
 603        if (!mk->mp) {
 604                num = 0;
 605                attrs = NULL;
 606        } else {
 607                num = mk->mp->num;
 608                attrs = mk->mp->grp.attrs;
 609        }
 610
 611        /* Enlarge. */
 612        new = krealloc(mk->mp,
 613                       sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 614                       GFP_KERNEL);
 615        if (!new) {
 616                kfree(attrs);
 617                err = -ENOMEM;
 618                goto fail;
 619        }
 620        /* Despite looking like the typical realloc() bug, this is safe.
 621         * We *want* the old 'attrs' to be freed either way, and we'll store
 622         * the new one in the success case. */
 623        attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 624        if (!attrs) {
 625                err = -ENOMEM;
 626                goto fail_free_new;
 627        }
 628
 629        /* Sysfs wants everything zeroed. */
 630        memset(new, 0, sizeof(*new));
 631        memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 632        memset(&attrs[num], 0, sizeof(attrs[num]));
 633        new->grp.name = "parameters";
 634        new->grp.attrs = attrs;
 635
 636        /* Tack new one on the end. */
 637        sysfs_attr_init(&new->attrs[num].mattr.attr);
 638        new->attrs[num].param = kp;
 639        new->attrs[num].mattr.show = param_attr_show;
 640        new->attrs[num].mattr.store = param_attr_store;
 641        new->attrs[num].mattr.attr.name = (char *)name;
 642        new->attrs[num].mattr.attr.mode = kp->perm;
 643        new->num = num+1;
 644
 645        /* Fix up all the pointers, since krealloc can move us */
 646        for (num = 0; num < new->num; num++)
 647                new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 648        new->grp.attrs[num] = NULL;
 649
 650        mk->mp = new;
 651        return 0;
 652
 653fail_free_new:
 654        kfree(new);
 655fail:
 656        mk->mp = NULL;
 657        return err;
 658}
 659
 660#ifdef CONFIG_MODULES
 661static void free_module_param_attrs(struct module_kobject *mk)
 662{
 663        kfree(mk->mp->grp.attrs);
 664        kfree(mk->mp);
 665        mk->mp = NULL;
 666}
 667
 668/*
 669 * module_param_sysfs_setup - setup sysfs support for one module
 670 * @mod: module
 671 * @kparam: module parameters (array)
 672 * @num_params: number of module parameters
 673 *
 674 * Adds sysfs entries for module parameters under
 675 * /sys/module/[mod->name]/parameters/
 676 */
 677int module_param_sysfs_setup(struct module *mod,
 678                             const struct kernel_param *kparam,
 679                             unsigned int num_params)
 680{
 681        int i, err;
 682        bool params = false;
 683
 684        for (i = 0; i < num_params; i++) {
 685                if (kparam[i].perm == 0)
 686                        continue;
 687                err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 688                if (err)
 689                        return err;
 690                params = true;
 691        }
 692
 693        if (!params)
 694                return 0;
 695
 696        /* Create the param group. */
 697        err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 698        if (err)
 699                free_module_param_attrs(&mod->mkobj);
 700        return err;
 701}
 702
 703/*
 704 * module_param_sysfs_remove - remove sysfs support for one module
 705 * @mod: module
 706 *
 707 * Remove sysfs entries for module parameters and the corresponding
 708 * kobject.
 709 */
 710void module_param_sysfs_remove(struct module *mod)
 711{
 712        if (mod->mkobj.mp) {
 713                sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 714                /* We are positive that no one is using any param
 715                 * attrs at this point.  Deallocate immediately. */
 716                free_module_param_attrs(&mod->mkobj);
 717        }
 718}
 719#endif
 720
 721void destroy_params(const struct kernel_param *params, unsigned num)
 722{
 723        unsigned int i;
 724
 725        for (i = 0; i < num; i++)
 726                if (params[i].ops->free)
 727                        params[i].ops->free(params[i].arg);
 728}
 729
 730static struct module_kobject * __init locate_module_kobject(const char *name)
 731{
 732        struct module_kobject *mk;
 733        struct kobject *kobj;
 734        int err;
 735
 736        kobj = kset_find_obj(module_kset, name);
 737        if (kobj) {
 738                mk = to_module_kobject(kobj);
 739        } else {
 740                mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 741                BUG_ON(!mk);
 742
 743                mk->mod = THIS_MODULE;
 744                mk->kobj.kset = module_kset;
 745                err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 746                                           "%s", name);
 747#ifdef CONFIG_MODULES
 748                if (!err)
 749                        err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 750#endif
 751                if (err) {
 752                        kobject_put(&mk->kobj);
 753                        pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 754                                name, err);
 755                        return NULL;
 756                }
 757
 758                /* So that we hold reference in both cases. */
 759                kobject_get(&mk->kobj);
 760        }
 761
 762        return mk;
 763}
 764
 765static void __init kernel_add_sysfs_param(const char *name,
 766                                          struct kernel_param *kparam,
 767                                          unsigned int name_skip)
 768{
 769        struct module_kobject *mk;
 770        int err;
 771
 772        mk = locate_module_kobject(name);
 773        if (!mk)
 774                return;
 775
 776        /* We need to remove old parameters before adding more. */
 777        if (mk->mp)
 778                sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 779
 780        /* These should not fail at boot. */
 781        err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 782        BUG_ON(err);
 783        err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 784        BUG_ON(err);
 785        kobject_uevent(&mk->kobj, KOBJ_ADD);
 786        kobject_put(&mk->kobj);
 787}
 788
 789/*
 790 * param_sysfs_builtin - add sysfs parameters for built-in modules
 791 *
 792 * Add module_parameters to sysfs for "modules" built into the kernel.
 793 *
 794 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 795 * "parameter" name is stored behind a dot in kernel_param->name. So,
 796 * extract the "module" name for all built-in kernel_param-eters,
 797 * and for all who have the same, call kernel_add_sysfs_param.
 798 */
 799static void __init param_sysfs_builtin(void)
 800{
 801        struct kernel_param *kp;
 802        unsigned int name_len;
 803        char modname[MODULE_NAME_LEN];
 804
 805        for (kp = __start___param; kp < __stop___param; kp++) {
 806                char *dot;
 807
 808                if (kp->perm == 0)
 809                        continue;
 810
 811                dot = strchr(kp->name, '.');
 812                if (!dot) {
 813                        /* This happens for core_param() */
 814                        strcpy(modname, "kernel");
 815                        name_len = 0;
 816                } else {
 817                        name_len = dot - kp->name + 1;
 818                        strlcpy(modname, kp->name, name_len);
 819                }
 820                kernel_add_sysfs_param(modname, kp, name_len);
 821        }
 822}
 823
 824ssize_t __modver_version_show(struct module_attribute *mattr,
 825                              struct module_kobject *mk, char *buf)
 826{
 827        struct module_version_attribute *vattr =
 828                container_of(mattr, struct module_version_attribute, mattr);
 829
 830        return sprintf(buf, "%s\n", vattr->version);
 831}
 832
 833extern const struct module_version_attribute *__start___modver[];
 834extern const struct module_version_attribute *__stop___modver[];
 835
 836static void __init version_sysfs_builtin(void)
 837{
 838        const struct module_version_attribute **p;
 839        struct module_kobject *mk;
 840        int err;
 841
 842        for (p = __start___modver; p < __stop___modver; p++) {
 843                const struct module_version_attribute *vattr = *p;
 844
 845                mk = locate_module_kobject(vattr->module_name);
 846                if (mk) {
 847                        err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 848                        kobject_uevent(&mk->kobj, KOBJ_ADD);
 849                        kobject_put(&mk->kobj);
 850                }
 851        }
 852}
 853
 854/* module-related sysfs stuff */
 855
 856static ssize_t module_attr_show(struct kobject *kobj,
 857                                struct attribute *attr,
 858                                char *buf)
 859{
 860        struct module_attribute *attribute;
 861        struct module_kobject *mk;
 862        int ret;
 863
 864        attribute = to_module_attr(attr);
 865        mk = to_module_kobject(kobj);
 866
 867        if (!attribute->show)
 868                return -EIO;
 869
 870        ret = attribute->show(attribute, mk, buf);
 871
 872        return ret;
 873}
 874
 875static ssize_t module_attr_store(struct kobject *kobj,
 876                                struct attribute *attr,
 877                                const char *buf, size_t len)
 878{
 879        struct module_attribute *attribute;
 880        struct module_kobject *mk;
 881        int ret;
 882
 883        attribute = to_module_attr(attr);
 884        mk = to_module_kobject(kobj);
 885
 886        if (!attribute->store)
 887                return -EIO;
 888
 889        ret = attribute->store(attribute, mk, buf, len);
 890
 891        return ret;
 892}
 893
 894static const struct sysfs_ops module_sysfs_ops = {
 895        .show = module_attr_show,
 896        .store = module_attr_store,
 897};
 898
 899static int uevent_filter(struct kset *kset, struct kobject *kobj)
 900{
 901        struct kobj_type *ktype = get_ktype(kobj);
 902
 903        if (ktype == &module_ktype)
 904                return 1;
 905        return 0;
 906}
 907
 908static const struct kset_uevent_ops module_uevent_ops = {
 909        .filter = uevent_filter,
 910};
 911
 912struct kset *module_kset;
 913int module_sysfs_initialized;
 914
 915struct kobj_type module_ktype = {
 916        .sysfs_ops =    &module_sysfs_ops,
 917};
 918
 919/*
 920 * param_sysfs_init - wrapper for built-in params support
 921 */
 922static int __init param_sysfs_init(void)
 923{
 924        module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 925        if (!module_kset) {
 926                printk(KERN_WARNING "%s (%d): error creating kset\n",
 927                        __FILE__, __LINE__);
 928                return -ENOMEM;
 929        }
 930        module_sysfs_initialized = 1;
 931
 932        version_sysfs_builtin();
 933        param_sysfs_builtin();
 934
 935        return 0;
 936}
 937subsys_initcall(param_sysfs_init);
 938
 939#endif /* CONFIG_SYSFS */
 940
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