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/module.h>
  19#include <linux/kernel.h>
  20#include <linux/string.h>
  21#include <linux/errno.h>
  22#include <linux/module.h>
  23#include <linux/device.h>
  24#include <linux/err.h>
  25#include <linux/slab.h>
  26#include <linux/ctype.h>
  27
  28#if 0
  29#define DEBUGP printk
  30#else
  31#define DEBUGP(fmt, a...)
  32#endif
  33
  34/* Protects all parameters, and incidentally kmalloced_param list. */
  35static DEFINE_MUTEX(param_lock);
  36
  37/* This just allows us to keep track of which parameters are kmalloced. */
  38struct kmalloced_param {
  39        struct list_head list;
  40        char val[];
  41};
  42static LIST_HEAD(kmalloced_params);
  43
  44static void *kmalloc_parameter(unsigned int size)
  45{
  46        struct kmalloced_param *p;
  47
  48        p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  49        if (!p)
  50                return NULL;
  51
  52        list_add(&p->list, &kmalloced_params);
  53        return p->val;
  54}
  55
  56/* Does nothing if parameter wasn't kmalloced above. */
  57static void maybe_kfree_parameter(void *param)
  58{
  59        struct kmalloced_param *p;
  60
  61        list_for_each_entry(p, &kmalloced_params, list) {
  62                if (p->val == param) {
  63                        list_del(&p->list);
  64                        kfree(p);
  65                        break;
  66                }
  67        }
  68}
  69
  70static char dash2underscore(char c)
  71{
  72        if (c == '-')
  73                return '_';
  74        return c;
  75}
  76
  77bool parameqn(const char *a, const char *b, size_t n)
  78{
  79        size_t i;
  80
  81        for (i = 0; i < n; i++) {
  82                if (dash2underscore(a[i]) != dash2underscore(b[i]))
  83                        return false;
  84        }
  85        return true;
  86}
  87
  88bool parameq(const char *a, const char *b)
  89{
  90        return parameqn(a, b, strlen(a)+1);
  91}
  92
  93static int parse_one(char *param,
  94                     char *val,
  95                     const struct kernel_param *params,
  96                     unsigned num_params,
  97                     int (*handle_unknown)(char *param, char *val))
  98{
  99        unsigned int i;
 100        int err;
 101
 102        /* Find parameter */
 103        for (i = 0; i < num_params; i++) {
 104                if (parameq(param, params[i].name)) {
 105                        /* No one handled NULL, so do it here. */
 106                        if (!val && params[i].ops->set != param_set_bool)
 107                                return -EINVAL;
 108                        DEBUGP("They are equal!  Calling %p\n",
 109                               params[i].ops->set);
 110                        mutex_lock(&param_lock);
 111                        err = params[i].ops->set(val, &params[i]);
 112                        mutex_unlock(&param_lock);
 113                        return err;
 114                }
 115        }
 116
 117        if (handle_unknown) {
 118                DEBUGP("Unknown argument: calling %p\n", handle_unknown);
 119                return handle_unknown(param, val);
 120        }
 121
 122        DEBUGP("Unknown argument `%s'\n", param);
 123        return -ENOENT;
 124}
 125
 126/* You can use " around spaces, but can't escape ". */
 127/* Hyphens and underscores equivalent in parameter names. */
 128static char *next_arg(char *args, char **param, char **val)
 129{
 130        unsigned int i, equals = 0;
 131        int in_quote = 0, quoted = 0;
 132        char *next;
 133
 134        if (*args == '"') {
 135                args++;
 136                in_quote = 1;
 137                quoted = 1;
 138        }
 139
 140        for (i = 0; args[i]; i++) {
 141                if (isspace(args[i]) && !in_quote)
 142                        break;
 143                if (equals == 0) {
 144                        if (args[i] == '=')
 145                                equals = i;
 146                }
 147                if (args[i] == '"')
 148                        in_quote = !in_quote;
 149        }
 150
 151        *param = args;
 152        if (!equals)
 153                *val = NULL;
 154        else {
 155                args[equals] = '\0';
 156                *val = args + equals + 1;
 157
 158                /* Don't include quotes in value. */
 159                if (**val == '"') {
 160                        (*val)++;
 161                        if (args[i-1] == '"')
 162                                args[i-1] = '\0';
 163                }
 164                if (quoted && args[i-1] == '"')
 165                        args[i-1] = '\0';
 166        }
 167
 168        if (args[i]) {
 169                args[i] = '\0';
 170                next = args + i + 1;
 171        } else
 172                next = args + i;
 173
 174        /* Chew up trailing spaces. */
 175        return skip_spaces(next);
 176}
 177
 178/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 179int parse_args(const char *name,
 180               char *args,
 181               const struct kernel_param *params,
 182               unsigned num,
 183               int (*unknown)(char *param, char *val))
 184{
 185        char *param, *val;
 186
 187        DEBUGP("Parsing ARGS: %s\n", args);
 188
 189        /* Chew leading spaces */
 190        args = skip_spaces(args);
 191
 192        while (*args) {
 193                int ret;
 194                int irq_was_disabled;
 195
 196                args = next_arg(args, &param, &val);
 197                irq_was_disabled = irqs_disabled();
 198                ret = parse_one(param, val, params, num, unknown);
 199                if (irq_was_disabled && !irqs_disabled()) {
 200                        printk(KERN_WARNING "parse_args(): option '%s' enabled "
 201                                        "irq's!\n", param);
 202                }
 203                switch (ret) {
 204                case -ENOENT:
 205                        printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 206                               name, param);
 207                        return ret;
 208                case -ENOSPC:
 209                        printk(KERN_ERR
 210                               "%s: `%s' too large for parameter `%s'\n",
 211                               name, val ?: "", param);
 212                        return ret;
 213                case 0:
 214                        break;
 215                default:
 216                        printk(KERN_ERR
 217                               "%s: `%s' invalid for parameter `%s'\n",
 218                               name, val ?: "", param);
 219                        return ret;
 220                }
 221        }
 222
 223        /* All parsed OK. */
 224        return 0;
 225}
 226
 227/* Lazy bastard, eh? */
 228#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 229        int param_set_##name(const char *val, const struct kernel_param *kp) \
 230        {                                                               \
 231                tmptype l;                                              \
 232                int ret;                                                \
 233                                                                        \
 234                ret = strtolfn(val, 0, &l);                             \
 235                if (ret < 0 || ((type)l != l))                          \
 236                        return ret < 0 ? ret : -EINVAL;                 \
 237                *((type *)kp->arg) = l;                                 \
 238                return 0;                                               \
 239        }                                                               \
 240        int param_get_##name(char *buffer, const struct kernel_param *kp) \
 241        {                                                               \
 242                return sprintf(buffer, format, *((type *)kp->arg));     \
 243        }                                                               \
 244        struct kernel_param_ops param_ops_##name = {                    \
 245                .set = param_set_##name,                                \
 246                .get = param_get_##name,                                \
 247        };                                                              \
 248        EXPORT_SYMBOL(param_set_##name);                                \
 249        EXPORT_SYMBOL(param_get_##name);                                \
 250        EXPORT_SYMBOL(param_ops_##name)
 251
 252
 253STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 254STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 255STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 256STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 257STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 258STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 259STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 260
 261int param_set_charp(const char *val, const struct kernel_param *kp)
 262{
 263        if (strlen(val) > 1024) {
 264                printk(KERN_ERR "%s: string parameter too long\n",
 265                       kp->name);
 266                return -ENOSPC;
 267        }
 268
 269        maybe_kfree_parameter(*(char **)kp->arg);
 270
 271        /* This is a hack.  We can't kmalloc in early boot, and we
 272         * don't need to; this mangled commandline is preserved. */
 273        if (slab_is_available()) {
 274                *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 275                if (!*(char **)kp->arg)
 276                        return -ENOMEM;
 277                strcpy(*(char **)kp->arg, val);
 278        } else
 279                *(const char **)kp->arg = val;
 280
 281        return 0;
 282}
 283EXPORT_SYMBOL(param_set_charp);
 284
 285int param_get_charp(char *buffer, const struct kernel_param *kp)
 286{
 287        return sprintf(buffer, "%s", *((char **)kp->arg));
 288}
 289EXPORT_SYMBOL(param_get_charp);
 290
 291static void param_free_charp(void *arg)
 292{
 293        maybe_kfree_parameter(*((char **)arg));
 294}
 295
 296struct kernel_param_ops param_ops_charp = {
 297        .set = param_set_charp,
 298        .get = param_get_charp,
 299        .free = param_free_charp,
 300};
 301EXPORT_SYMBOL(param_ops_charp);
 302
 303/* Actually could be a bool or an int, for historical reasons. */
 304int param_set_bool(const char *val, const struct kernel_param *kp)
 305{
 306        bool v;
 307        int ret;
 308
 309        /* No equals means "set"... */
 310        if (!val) val = "1";
 311
 312        /* One of =[yYnN01] */
 313        ret = strtobool(val, &v);
 314        if (ret)
 315                return ret;
 316
 317        if (kp->flags & KPARAM_ISBOOL)
 318                *(bool *)kp->arg = v;
 319        else
 320                *(int *)kp->arg = v;
 321        return 0;
 322}
 323EXPORT_SYMBOL(param_set_bool);
 324
 325int param_get_bool(char *buffer, const struct kernel_param *kp)
 326{
 327        bool val;
 328        if (kp->flags & KPARAM_ISBOOL)
 329                val = *(bool *)kp->arg;
 330        else
 331                val = *(int *)kp->arg;
 332
 333        /* Y and N chosen as being relatively non-coder friendly */
 334        return sprintf(buffer, "%c", val ? 'Y' : 'N');
 335}
 336EXPORT_SYMBOL(param_get_bool);
 337
 338struct kernel_param_ops param_ops_bool = {
 339        .set = param_set_bool,
 340        .get = param_get_bool,
 341};
 342EXPORT_SYMBOL(param_ops_bool);
 343
 344/* This one must be bool. */
 345int param_set_invbool(const char *val, const struct kernel_param *kp)
 346{
 347        int ret;
 348        bool boolval;
 349        struct kernel_param dummy;
 350
 351        dummy.arg = &boolval;
 352        dummy.flags = KPARAM_ISBOOL;
 353        ret = param_set_bool(val, &dummy);
 354        if (ret == 0)
 355                *(bool *)kp->arg = !boolval;
 356        return ret;
 357}
 358EXPORT_SYMBOL(param_set_invbool);
 359
 360int param_get_invbool(char *buffer, const struct kernel_param *kp)
 361{
 362        return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 363}
 364EXPORT_SYMBOL(param_get_invbool);
 365
 366struct kernel_param_ops param_ops_invbool = {
 367        .set = param_set_invbool,
 368        .get = param_get_invbool,
 369};
 370EXPORT_SYMBOL(param_ops_invbool);
 371
 372/* We break the rule and mangle the string. */
 373static int param_array(const char *name,
 374                       const char *val,
 375                       unsigned int min, unsigned int max,
 376                       void *elem, int elemsize,
 377                       int (*set)(const char *, const struct kernel_param *kp),
 378                       u16 flags,
 379                       unsigned int *num)
 380{
 381        int ret;
 382        struct kernel_param kp;
 383        char save;
 384
 385        /* Get the name right for errors. */
 386        kp.name = name;
 387        kp.arg = elem;
 388        kp.flags = flags;
 389
 390        *num = 0;
 391        /* We expect a comma-separated list of values. */
 392        do {
 393                int len;
 394
 395                if (*num == max) {
 396                        printk(KERN_ERR "%s: can only take %i arguments\n",
 397                               name, max);
 398                        return -EINVAL;
 399                }
 400                len = strcspn(val, ",");
 401
 402                /* nul-terminate and parse */
 403                save = val[len];
 404                ((char *)val)[len] = '\0';
 405                BUG_ON(!mutex_is_locked(&param_lock));
 406                ret = set(val, &kp);
 407
 408                if (ret != 0)
 409                        return ret;
 410                kp.arg += elemsize;
 411                val += len+1;
 412                (*num)++;
 413        } while (save == ',');
 414
 415        if (*num < min) {
 416                printk(KERN_ERR "%s: needs at least %i arguments\n",
 417                       name, min);
 418                return -EINVAL;
 419        }
 420        return 0;
 421}
 422
 423static int param_array_set(const char *val, const struct kernel_param *kp)
 424{
 425        const struct kparam_array *arr = kp->arr;
 426        unsigned int temp_num;
 427
 428        return param_array(kp->name, val, 1, arr->max, arr->elem,
 429                           arr->elemsize, arr->ops->set, kp->flags,
 430                           arr->num ?: &temp_num);
 431}
 432
 433static int param_array_get(char *buffer, const struct kernel_param *kp)
 434{
 435        int i, off, ret;
 436        const struct kparam_array *arr = kp->arr;
 437        struct kernel_param p;
 438
 439        p = *kp;
 440        for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 441                if (i)
 442                        buffer[off++] = ',';
 443                p.arg = arr->elem + arr->elemsize * i;
 444                BUG_ON(!mutex_is_locked(&param_lock));
 445                ret = arr->ops->get(buffer + off, &p);
 446                if (ret < 0)
 447                        return ret;
 448                off += ret;
 449        }
 450        buffer[off] = '\0';
 451        return off;
 452}
 453
 454static void param_array_free(void *arg)
 455{
 456        unsigned int i;
 457        const struct kparam_array *arr = arg;
 458
 459        if (arr->ops->free)
 460                for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 461                        arr->ops->free(arr->elem + arr->elemsize * i);
 462}
 463
 464struct kernel_param_ops param_array_ops = {
 465        .set = param_array_set,
 466        .get = param_array_get,
 467        .free = param_array_free,
 468};
 469EXPORT_SYMBOL(param_array_ops);
 470
 471int param_set_copystring(const char *val, const struct kernel_param *kp)
 472{
 473        const struct kparam_string *kps = kp->str;
 474
 475        if (strlen(val)+1 > kps->maxlen) {
 476                printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 477                       kp->name, kps->maxlen-1);
 478                return -ENOSPC;
 479        }
 480        strcpy(kps->string, val);
 481        return 0;
 482}
 483EXPORT_SYMBOL(param_set_copystring);
 484
 485int param_get_string(char *buffer, const struct kernel_param *kp)
 486{
 487        const struct kparam_string *kps = kp->str;
 488        return strlcpy(buffer, kps->string, kps->maxlen);
 489}
 490EXPORT_SYMBOL(param_get_string);
 491
 492struct kernel_param_ops param_ops_string = {
 493        .set = param_set_copystring,
 494        .get = param_get_string,
 495};
 496EXPORT_SYMBOL(param_ops_string);
 497
 498/* sysfs output in /sys/modules/XYZ/parameters/ */
 499#define to_module_attr(n) container_of(n, struct module_attribute, attr)
 500#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 501
 502extern struct kernel_param __start___param[], __stop___param[];
 503
 504struct param_attribute
 505{
 506        struct module_attribute mattr;
 507        const struct kernel_param *param;
 508};
 509
 510struct module_param_attrs
 511{
 512        unsigned int num;
 513        struct attribute_group grp;
 514        struct param_attribute attrs[0];
 515};
 516
 517#ifdef CONFIG_SYSFS
 518#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 519
 520static ssize_t param_attr_show(struct module_attribute *mattr,
 521                               struct module_kobject *mk, char *buf)
 522{
 523        int count;
 524        struct param_attribute *attribute = to_param_attr(mattr);
 525
 526        if (!attribute->param->ops->get)
 527                return -EPERM;
 528
 529        mutex_lock(&param_lock);
 530        count = attribute->param->ops->get(buf, attribute->param);
 531        mutex_unlock(&param_lock);
 532        if (count > 0) {
 533                strcat(buf, "\n");
 534                ++count;
 535        }
 536        return count;
 537}
 538
 539/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 540static ssize_t param_attr_store(struct module_attribute *mattr,
 541                                struct module_kobject *km,
 542                                const char *buf, size_t len)
 543{
 544        int err;
 545        struct param_attribute *attribute = to_param_attr(mattr);
 546
 547        if (!attribute->param->ops->set)
 548                return -EPERM;
 549
 550        mutex_lock(&param_lock);
 551        err = attribute->param->ops->set(buf, attribute->param);
 552        mutex_unlock(&param_lock);
 553        if (!err)
 554                return len;
 555        return err;
 556}
 557#endif
 558
 559#ifdef CONFIG_MODULES
 560#define __modinit
 561#else
 562#define __modinit __init
 563#endif
 564
 565#ifdef CONFIG_SYSFS
 566void __kernel_param_lock(void)
 567{
 568        mutex_lock(&param_lock);
 569}
 570EXPORT_SYMBOL(__kernel_param_lock);
 571
 572void __kernel_param_unlock(void)
 573{
 574        mutex_unlock(&param_lock);
 575}
 576EXPORT_SYMBOL(__kernel_param_unlock);
 577
 578/*
 579 * add_sysfs_param - add a parameter to sysfs
 580 * @mk: struct module_kobject
 581 * @kparam: the actual parameter definition to add to sysfs
 582 * @name: name of parameter
 583 *
 584 * Create a kobject if for a (per-module) parameter if mp NULL, and
 585 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 586 * if there's an error.
 587 */
 588static __modinit int add_sysfs_param(struct module_kobject *mk,
 589                                     const struct kernel_param *kp,
 590                                     const char *name)
 591{
 592        struct module_param_attrs *new;
 593        struct attribute **attrs;
 594        int err, num;
 595
 596        /* We don't bother calling this with invisible parameters. */
 597        BUG_ON(!kp->perm);
 598
 599        if (!mk->mp) {
 600                num = 0;
 601                attrs = NULL;
 602        } else {
 603                num = mk->mp->num;
 604                attrs = mk->mp->grp.attrs;
 605        }
 606
 607        /* Enlarge. */
 608        new = krealloc(mk->mp,
 609                       sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 610                       GFP_KERNEL);
 611        if (!new) {
 612                kfree(mk->mp);
 613                err = -ENOMEM;
 614                goto fail;
 615        }
 616        attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 617        if (!attrs) {
 618                err = -ENOMEM;
 619                goto fail_free_new;
 620        }
 621
 622        /* Sysfs wants everything zeroed. */
 623        memset(new, 0, sizeof(*new));
 624        memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 625        memset(&attrs[num], 0, sizeof(attrs[num]));
 626        new->grp.name = "parameters";
 627        new->grp.attrs = attrs;
 628
 629        /* Tack new one on the end. */
 630        sysfs_attr_init(&new->attrs[num].mattr.attr);
 631        new->attrs[num].param = kp;
 632        new->attrs[num].mattr.show = param_attr_show;
 633        new->attrs[num].mattr.store = param_attr_store;
 634        new->attrs[num].mattr.attr.name = (char *)name;
 635        new->attrs[num].mattr.attr.mode = kp->perm;
 636        new->num = num+1;
 637
 638        /* Fix up all the pointers, since krealloc can move us */
 639        for (num = 0; num < new->num; num++)
 640                new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 641        new->grp.attrs[num] = NULL;
 642
 643        mk->mp = new;
 644        return 0;
 645
 646fail_free_new:
 647        kfree(new);
 648fail:
 649        mk->mp = NULL;
 650        return err;
 651}
 652
 653#ifdef CONFIG_MODULES
 654static void free_module_param_attrs(struct module_kobject *mk)
 655{
 656        kfree(mk->mp->grp.attrs);
 657        kfree(mk->mp);
 658        mk->mp = NULL;
 659}
 660
 661/*
 662 * module_param_sysfs_setup - setup sysfs support for one module
 663 * @mod: module
 664 * @kparam: module parameters (array)
 665 * @num_params: number of module parameters
 666 *
 667 * Adds sysfs entries for module parameters under
 668 * /sys/module/[mod->name]/parameters/
 669 */
 670int module_param_sysfs_setup(struct module *mod,
 671                             const struct kernel_param *kparam,
 672                             unsigned int num_params)
 673{
 674        int i, err;
 675        bool params = false;
 676
 677        for (i = 0; i < num_params; i++) {
 678                if (kparam[i].perm == 0)
 679                        continue;
 680                err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 681                if (err)
 682                        return err;
 683                params = true;
 684        }
 685
 686        if (!params)
 687                return 0;
 688
 689        /* Create the param group. */
 690        err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 691        if (err)
 692                free_module_param_attrs(&mod->mkobj);
 693        return err;
 694}
 695
 696/*
 697 * module_param_sysfs_remove - remove sysfs support for one module
 698 * @mod: module
 699 *
 700 * Remove sysfs entries for module parameters and the corresponding
 701 * kobject.
 702 */
 703void module_param_sysfs_remove(struct module *mod)
 704{
 705        if (mod->mkobj.mp) {
 706                sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 707                /* We are positive that no one is using any param
 708                 * attrs at this point.  Deallocate immediately. */
 709                free_module_param_attrs(&mod->mkobj);
 710        }
 711}
 712#endif
 713
 714void destroy_params(const struct kernel_param *params, unsigned num)
 715{
 716        unsigned int i;
 717
 718        for (i = 0; i < num; i++)
 719                if (params[i].ops->free)
 720                        params[i].ops->free(params[i].arg);
 721}
 722
 723static struct module_kobject * __init locate_module_kobject(const char *name)
 724{
 725        struct module_kobject *mk;
 726        struct kobject *kobj;
 727        int err;
 728
 729        kobj = kset_find_obj(module_kset, name);
 730        if (kobj) {
 731                mk = to_module_kobject(kobj);
 732        } else {
 733                mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 734                BUG_ON(!mk);
 735
 736                mk->mod = THIS_MODULE;
 737                mk->kobj.kset = module_kset;
 738                err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 739                                           "%s", name);
 740#ifdef CONFIG_MODULES
 741                if (!err)
 742                        err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 743#endif
 744                if (err) {
 745                        kobject_put(&mk->kobj);
 746                        printk(KERN_ERR
 747                                "Module '%s' failed add to sysfs, error number %d\n",
 748                                name, err);
 749                        printk(KERN_ERR
 750                                "The system will be unstable now.\n");
 751                        return NULL;
 752                }
 753
 754                /* So that we hold reference in both cases. */
 755                kobject_get(&mk->kobj);
 756        }
 757
 758        return mk;
 759}
 760
 761static void __init kernel_add_sysfs_param(const char *name,
 762                                          struct kernel_param *kparam,
 763                                          unsigned int name_skip)
 764{
 765        struct module_kobject *mk;
 766        int err;
 767
 768        mk = locate_module_kobject(name);
 769        if (!mk)
 770                return;
 771
 772        /* We need to remove old parameters before adding more. */
 773        if (mk->mp)
 774                sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 775
 776        /* These should not fail at boot. */
 777        err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 778        BUG_ON(err);
 779        err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 780        BUG_ON(err);
 781        kobject_uevent(&mk->kobj, KOBJ_ADD);
 782        kobject_put(&mk->kobj);
 783}
 784
 785/*
 786 * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 787 *
 788 * Add module_parameters to sysfs for "modules" built into the kernel.
 789 *
 790 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 791 * "parameter" name is stored behind a dot in kernel_param->name. So,
 792 * extract the "module" name for all built-in kernel_param-eters,
 793 * and for all who have the same, call kernel_add_sysfs_param.
 794 */
 795static void __init param_sysfs_builtin(void)
 796{
 797        struct kernel_param *kp;
 798        unsigned int name_len;
 799        char modname[MODULE_NAME_LEN];
 800
 801        for (kp = __start___param; kp < __stop___param; kp++) {
 802                char *dot;
 803
 804                if (kp->perm == 0)
 805                        continue;
 806
 807                dot = strchr(kp->name, '.');
 808                if (!dot) {
 809                        /* This happens for core_param() */
 810                        strcpy(modname, "kernel");
 811                        name_len = 0;
 812                } else {
 813                        name_len = dot - kp->name + 1;
 814                        strlcpy(modname, kp->name, name_len);
 815                }
 816                kernel_add_sysfs_param(modname, kp, name_len);
 817        }
 818}
 819
 820ssize_t __modver_version_show(struct module_attribute *mattr,
 821                              struct module_kobject *mk, char *buf)
 822{
 823        struct module_version_attribute *vattr =
 824                container_of(mattr, struct module_version_attribute, mattr);
 825
 826        return sprintf(buf, "%s\n", vattr->version);
 827}
 828
 829extern const struct module_version_attribute *__start___modver[];
 830extern const struct module_version_attribute *__stop___modver[];
 831
 832static void __init version_sysfs_builtin(void)
 833{
 834        const struct module_version_attribute **p;
 835        struct module_kobject *mk;
 836        int err;
 837
 838        for (p = __start___modver; p < __stop___modver; p++) {
 839                const struct module_version_attribute *vattr = *p;
 840
 841                mk = locate_module_kobject(vattr->module_name);
 842                if (mk) {
 843                        err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 844                        kobject_uevent(&mk->kobj, KOBJ_ADD);
 845                        kobject_put(&mk->kobj);
 846                }
 847        }
 848}
 849
 850/* module-related sysfs stuff */
 851
 852static ssize_t module_attr_show(struct kobject *kobj,
 853                                struct attribute *attr,
 854                                char *buf)
 855{
 856        struct module_attribute *attribute;
 857        struct module_kobject *mk;
 858        int ret;
 859
 860        attribute = to_module_attr(attr);
 861        mk = to_module_kobject(kobj);
 862
 863        if (!attribute->show)
 864                return -EIO;
 865
 866        ret = attribute->show(attribute, mk, buf);
 867
 868        return ret;
 869}
 870
 871static ssize_t module_attr_store(struct kobject *kobj,
 872                                struct attribute *attr,
 873                                const char *buf, size_t len)
 874{
 875        struct module_attribute *attribute;
 876        struct module_kobject *mk;
 877        int ret;
 878
 879        attribute = to_module_attr(attr);
 880        mk = to_module_kobject(kobj);
 881
 882        if (!attribute->store)
 883                return -EIO;
 884
 885        ret = attribute->store(attribute, mk, buf, len);
 886
 887        return ret;
 888}
 889
 890static const struct sysfs_ops module_sysfs_ops = {
 891        .show = module_attr_show,
 892        .store = module_attr_store,
 893};
 894
 895static int uevent_filter(struct kset *kset, struct kobject *kobj)
 896{
 897        struct kobj_type *ktype = get_ktype(kobj);
 898
 899        if (ktype == &module_ktype)
 900                return 1;
 901        return 0;
 902}
 903
 904static const struct kset_uevent_ops module_uevent_ops = {
 905        .filter = uevent_filter,
 906};
 907
 908struct kset *module_kset;
 909int module_sysfs_initialized;
 910
 911struct kobj_type module_ktype = {
 912        .sysfs_ops =    &module_sysfs_ops,
 913};
 914
 915/*
 916 * param_sysfs_init - wrapper for built-in params support
 917 */
 918static int __init param_sysfs_init(void)
 919{
 920        module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 921        if (!module_kset) {
 922                printk(KERN_WARNING "%s (%d): error creating kset\n",
 923                        __FILE__, __LINE__);
 924                return -ENOMEM;
 925        }
 926        module_sysfs_initialized = 1;
 927
 928        version_sysfs_builtin();
 929        param_sysfs_builtin();
 930
 931        return 0;
 932}
 933subsys_initcall(param_sysfs_init);
 934
 935#endif /* CONFIG_SYSFS */
 936
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