kernel/params.c

   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/config.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/kernel.h>
  21 #include <linux/string.h>
  22 #include <linux/errno.h>
  23 #include <linux/module.h>
  24 #include <linux/device.h>
  25 #include <linux/err.h>
  26 #include <linux/slab.h>
  27
  28 #if 0
  29 #define DEBUGP printk
  30 #else
  31 #define DEBUGP(fmt, a...)
  32 #endif
  33
  34 static inline int dash2underscore(char c)
  35 {
  36         if (c == '-')
  37                 return '_';
  38         return c;
  39 }
  40
  41 static inline int parameq(const char *input, const char *paramname)
  42 {
  43         unsigned int i;
  44         for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
  45                 if (input[i] == '\0')
  46                         return 1;
  47         return 0;
  48 }
  49
  50 static int parse_one(char *param,
  51                      char *val,
  52                      struct kernel_param *params,
  53                      unsigned num_params,
  54                      int (*handle_unknown)(char *param, char *val))
  55 {
  56         unsigned int i;
  57
  58         /* Find parameter */
  59         for (i = 0; i < num_params; i++) {
  60                 if (parameq(param, params[i].name)) {
  61                         DEBUGP("They are equal!  Calling %p\n",
  62                                params[i].set);
  63                         return params[i].set(val, &params[i]);
  64                 }
  65         }
  66
  67         if (handle_unknown) {
  68                 DEBUGP("Unknown argument: calling %p\n", handle_unknown);
  69                 return handle_unknown(param, val);
  70         }
  71
  72         DEBUGP("Unknown argument `%s'\n", param);
  73         return -ENOENT;
  74 }
  75
  76 /* You can use " around spaces, but can't escape ". */
  77 /* Hyphens and underscores equivalent in parameter names. */
  78 static char *next_arg(char *args, char **param, char **val)
  79 {
  80         unsigned int i, equals = 0;
  81         int in_quote = 0, quoted = 0;
  82         char *next;
  83
  84         if (*args == '"') {
  85                 args++;
  86                 in_quote = 1;
  87                 quoted = 1;
  88         }
  89
  90         for (i = 0; args[i]; i++) {
  91                 if (args[i] == ' ' && !in_quote)
  92                         break;
  93                 if (equals == 0) {
  94                         if (args[i] == '=')
  95                                 equals = i;
  96                 }
  97                 if (args[i] == '"')
  98                         in_quote = !in_quote;
  99         }
 100
 101         *param = args;
 102         if (!equals)
 103                 *val = NULL;
 104         else {
 105                 args[equals] = '\0';
 106                 *val = args + equals + 1;
 107
 108                 /* Don't include quotes in value. */
 109                 if (**val == '"') {
 110                         (*val)++;
 111                         if (args[i-1] == '"')
 112                                 args[i-1] = '\0';
 113                 }
 114                 if (quoted && args[i-1] == '"')
 115                         args[i-1] = '\0';
 116         }
 117
 118         if (args[i]) {
 119                 args[i] = '\0';
 120                 next = args + i + 1;
 121         } else
 122                 next = args + i;
 123
 124         /* Chew up trailing spaces. */
 125         while (*next == ' ')
 126                 next++;
 127         return next;
 128 }
 129
 130 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 131 int parse_args(const char *name,
 132                char *args,
 133                struct kernel_param *params,
 134                unsigned num,
 135                int (*unknown)(char *param, char *val))
 136 {
 137         char *param, *val;
 138
 139         DEBUGP("Parsing ARGS: %s\n", args);
 140
 141         /* Chew leading spaces */
 142         while (*args == ' ')
 143                 args++;
 144
 145         while (*args) {
 146                 int ret;
 147
 148                 args = next_arg(args, &param, &val);
 149                 ret = parse_one(param, val, params, num, unknown);
 150                 switch (ret) {
 151                 case -ENOENT:
 152                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 153                                name, param);
 154                         return ret;
 155                 case -ENOSPC:
 156                         printk(KERN_ERR
 157                                "%s: `%s' too large for parameter `%s'\n",
 158                                name, val ?: "", param);
 159                         return ret;
 160                 case 0:
 161                         break;
 162                 default:
 163                         printk(KERN_ERR
 164                                "%s: `%s' invalid for parameter `%s'\n",
 165                                name, val ?: "", param);
 166                         return ret;
 167                 }
 168         }
 169
 170         /* All parsed OK. */
 171         return 0;
 172 }
 173
 174 /* Lazy bastard, eh? */
 175 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 176         int param_set_##name(const char *val, struct kernel_param *kp)  \
 177         {                                                               \
 178                 char *endp;                                             \
 179                 tmptype l;                                              \
 180                                                                         \
 181                 if (!val) return -EINVAL;                               \
 182                 l = strtolfn(val, &endp, 0);                            \
 183                 if (endp == val || ((type)l != l))                      \
 184                         return -EINVAL;                                 \
 185                 *((type *)kp->arg) = l;                                 \
 186                 return 0;                                               \
 187         }                                                               \
 188         int param_get_##name(char *buffer, struct kernel_param *kp)     \
 189         {                                                               \
 190                 return sprintf(buffer, format, *((type *)kp->arg));     \
 191         }
 192
 193 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, simple_strtoul);
 194 STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
 195 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, simple_strtoul);
 196 STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
 197 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, simple_strtoul);
 198 STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
 199 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);
 200
 201 int param_set_charp(const char *val, struct kernel_param *kp)
 202 {
 203         if (!val) {
 204                 printk(KERN_ERR "%s: string parameter expected\n",
 205                        kp->name);
 206                 return -EINVAL;
 207         }
 208
 209         if (strlen(val) > 1024) {
 210                 printk(KERN_ERR "%s: string parameter too long\n",
 211                        kp->name);
 212                 return -ENOSPC;
 213         }
 214
 215         *(char **)kp->arg = (char *)val;
 216         return 0;
 217 }
 218
 219 int param_get_charp(char *buffer, struct kernel_param *kp)
 220 {
 221         return sprintf(buffer, "%s", *((char **)kp->arg));
 222 }
 223
 224 int param_set_bool(const char *val, struct kernel_param *kp)
 225 {
 226         /* No equals means "set"... */
 227         if (!val) val = "1";
 228
 229         /* One of =[yYnN01] */
 230         switch (val[0]) {
 231         case 'y': case 'Y': case '1':
 232                 *(int *)kp->arg = 1;
 233                 return 0;
 234         case 'n': case 'N': case '0':
 235                 *(int *)kp->arg = 0;
 236                 return 0;
 237         }
 238         return -EINVAL;
 239 }
 240
 241 int param_get_bool(char *buffer, struct kernel_param *kp)
 242 {
 243         /* Y and N chosen as being relatively non-coder friendly */
 244         return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
 245 }
 246
 247 int param_set_invbool(const char *val, struct kernel_param *kp)
 248 {
 249         int boolval, ret;
 250         struct kernel_param dummy = { .arg = &boolval };
 251
 252         ret = param_set_bool(val, &dummy);
 253         if (ret == 0)
 254                 *(int *)kp->arg = !boolval;
 255         return ret;
 256 }
 257
 258 int param_get_invbool(char *buffer, struct kernel_param *kp)
 259 {
 260         int val;
 261         struct kernel_param dummy = { .arg = &val };
 262
 263         val = !*(int *)kp->arg;
 264         return param_get_bool(buffer, &dummy);
 265 }
 266
 267 /* We cheat here and temporarily mangle the string. */
 268 int param_array(const char *name,
 269                 const char *val,
 270                 unsigned int min, unsigned int max,
 271                 void *elem, int elemsize,
 272                 int (*set)(const char *, struct kernel_param *kp),
 273                 int *num)
 274 {
 275         int ret;
 276         struct kernel_param kp;
 277         char save;
 278
 279         /* Get the name right for errors. */
 280         kp.name = name;
 281         kp.arg = elem;
 282
 283         /* No equals sign? */
 284         if (!val) {
 285                 printk(KERN_ERR "%s: expects arguments\n", name);
 286                 return -EINVAL;
 287         }
 288
 289         *num = 0;
 290         /* We expect a comma-separated list of values. */
 291         do {
 292                 int len;
 293
 294                 if (*num == max) {
 295                         printk(KERN_ERR "%s: can only take %i arguments\n",
 296                                name, max);
 297                         return -EINVAL;
 298                 }
 299                 len = strcspn(val, ",");
 300
 301                 /* nul-terminate and parse */
 302                 save = val[len];
 303                 ((char *)val)[len] = '\0';
 304                 ret = set(val, &kp);
 305
 306                 if (ret != 0)
 307                         return ret;
 308                 kp.arg += elemsize;
 309                 val += len+1;
 310                 (*num)++;
 311         } while (save == ',');
 312
 313         if (*num < min) {
 314                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 315                        name, min);
 316                 return -EINVAL;
 317         }
 318         return 0;
 319 }
 320
 321 int param_array_set(const char *val, struct kernel_param *kp)
 322 {
 323         struct kparam_array *arr = kp->arg;
 324         unsigned int temp_num;
 325
 326         return param_array(kp->name, val, 1, arr->max, arr->elem,
 327                            arr->elemsize, arr->set, arr->num ?: &temp_num);
 328 }
 329
 330 int param_array_get(char *buffer, struct kernel_param *kp)
 331 {
 332         int i, off, ret;
 333         struct kparam_array *arr = kp->arg;
 334         struct kernel_param p;
 335
 336         p = *kp;
 337         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 338                 if (i)
 339                         buffer[off++] = ',';
 340                 p.arg = arr->elem + arr->elemsize * i;
 341                 ret = arr->get(buffer + off, &p);
 342                 if (ret < 0)
 343                         return ret;
 344                 off += ret;
 345         }
 346         buffer[off] = '\0';
 347         return off;
 348 }
 349
 350 int param_set_copystring(const char *val, struct kernel_param *kp)
 351 {
 352         struct kparam_string *kps = kp->arg;
 353
 354         if (strlen(val)+1 > kps->maxlen) {
 355                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 356                        kp->name, kps->maxlen-1);
 357                 return -ENOSPC;
 358         }
 359         strcpy(kps->string, val);
 360         return 0;
 361 }
 362
 363 int param_get_string(char *buffer, struct kernel_param *kp)
 364 {
 365         struct kparam_string *kps = kp->arg;
 366         return strlcpy(buffer, kps->string, kps->maxlen);
 367 }
 368
 369 /* sysfs output in /sys/modules/XYZ/parameters/ */
 370
 371 extern struct kernel_param __start___param[], __stop___param[];
 372
 373 #define MAX_KBUILD_MODNAME KOBJ_NAME_LEN
 374
 375 struct param_attribute
 376 {
 377         struct module_attribute mattr;
 378         struct kernel_param *param;
 379 };
 380
 381 struct module_param_attrs
 382 {
 383         struct attribute_group grp;
 384         struct param_attribute attrs[0];
 385 };
 386
 387 #define to_param_attr(n) container_of(n, struct param_attribute, mattr);
 388
 389 static ssize_t param_attr_show(struct module_attribute *mattr,
 390                                struct module *mod, char *buf)
 391 {
 392         int count;
 393         struct param_attribute *attribute = to_param_attr(mattr);
 394
 395         if (!attribute->param->get)
 396                 return -EPERM;
 397
 398         count = attribute->param->get(buf, attribute->param);
 399         if (count > 0) {
 400                 strcat(buf, "\n");
 401                 ++count;
 402         }
 403         return count;
 404 }
 405
 406 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 407 static ssize_t param_attr_store(struct module_attribute *mattr,
 408                                 struct module *owner,
 409                                 const char *buf, size_t len)
 410 {
 411         int err;
 412         struct param_attribute *attribute = to_param_attr(mattr);
 413
 414         if (!attribute->param->set)
 415                 return -EPERM;
 416
 417         err = attribute->param->set(buf, attribute->param);
 418         if (!err)
 419                 return len;
 420         return err;
 421 }
 422
 423 #ifdef CONFIG_MODULES
 424 #define __modinit
 425 #else
 426 #define __modinit __init
 427 #endif
 428
 429 /*
 430  * param_sysfs_setup - setup sysfs support for one module or KBUILD_MODNAME
 431  * @mk: struct module_kobject (contains parent kobject)
 432  * @kparam: array of struct kernel_param, the actual parameter definitions
 433  * @num_params: number of entries in array
 434  * @name_skip: offset where the parameter name start in kparam[].name. Needed for built-in "modules"
 435  *
 436  * Create a kobject for a (per-module) group of parameters, and create files
 437  * in sysfs. A pointer to the param_kobject is returned on success,
 438  * NULL if there's no parameter to export, or other ERR_PTR(err).
 439  */
 440 static __modinit struct module_param_attrs *
 441 param_sysfs_setup(struct module_kobject *mk,
 442                   struct kernel_param *kparam,
 443                   unsigned int num_params,
 444                   unsigned int name_skip)
 445 {
 446         struct module_param_attrs *mp;
 447         unsigned int valid_attrs = 0;
 448         unsigned int i, size[2];
 449         struct param_attribute *pattr;
 450         struct attribute **gattr;
 451         int err;
 452
 453         for (i=0; i<num_params; i++) {
 454                 if (kparam[i].perm)
 455                         valid_attrs++;
 456         }
 457
 458         if (!valid_attrs)
 459                 return NULL;
 460
 461         size[0] = ALIGN(sizeof(*mp) +
 462                         valid_attrs * sizeof(mp->attrs[0]),
 463                         sizeof(mp->grp.attrs[0]));
 464         size[1] = (valid_attrs + 1) * sizeof(mp->grp.attrs[0]);
 465
 466         mp = kmalloc(size[0] + size[1], GFP_KERNEL);
 467         if (!mp)
 468                 return ERR_PTR(-ENOMEM);
 469
 470         mp->grp.name = "parameters";
 471         mp->grp.attrs = (void *)mp + size[0];
 472
 473         pattr = &mp->attrs[0];
 474         gattr = &mp->grp.attrs[0];
 475         for (i = 0; i < num_params; i++) {
 476                 struct kernel_param *kp = &kparam[i];
 477                 if (kp->perm) {
 478                         pattr->param = kp;
 479                         pattr->mattr.show = param_attr_show;
 480                         pattr->mattr.store = param_attr_store;
 481                         pattr->mattr.attr.name = (char *)&kp->name[name_skip];
 482                         pattr->mattr.attr.owner = mk->mod;
 483                         pattr->mattr.attr.mode = kp->perm;
 484                         *(gattr++) = &(pattr++)->mattr.attr;
 485                 }
 486         }
 487         *gattr = NULL;
 488
 489         if ((err = sysfs_create_group(&mk->kobj, &mp->grp))) {
 490                 kfree(mp);
 491                 return ERR_PTR(err);
 492         }
 493         return mp;
 494 }
 495
 496
 497 #ifdef CONFIG_MODULES
 498
 499 /*
 500  * module_param_sysfs_setup - setup sysfs support for one module
 501  * @mod: module
 502  * @kparam: module parameters (array)
 503  * @num_params: number of module parameters
 504  *
 505  * Adds sysfs entries for module parameters, and creates a link from
 506  * /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
 507  */
 508 int module_param_sysfs_setup(struct module *mod,
 509                              struct kernel_param *kparam,
 510                              unsigned int num_params)
 511 {
 512         struct module_param_attrs *mp;
 513
 514         mp = param_sysfs_setup(&mod->mkobj, kparam, num_params, 0);
 515         if (IS_ERR(mp))
 516                 return PTR_ERR(mp);
 517
 518         mod->param_attrs = mp;
 519         return 0;
 520 }
 521
 522 /*
 523  * module_param_sysfs_remove - remove sysfs support for one module
 524  * @mod: module
 525  *
 526  * Remove sysfs entries for module parameters and the corresponding
 527  * kobject.
 528  */
 529 void module_param_sysfs_remove(struct module *mod)
 530 {
 531         if (mod->param_attrs) {
 532                 sysfs_remove_group(&mod->mkobj.kobj,
 533                                    &mod->param_attrs->grp);
 534                 /* We are positive that no one is using any param
 535                  * attrs at this point.  Deallocate immediately. */
 536                 kfree(mod->param_attrs);
 537                 mod->param_attrs = NULL;
 538         }
 539 }
 540 #endif
 541
 542 /*
 543  * kernel_param_sysfs_setup - wrapper for built-in params support
 544  */
 545 static void __init kernel_param_sysfs_setup(const char *name,
 546                                             struct kernel_param *kparam,
 547                                             unsigned int num_params,
 548                                             unsigned int name_skip)
 549 {
 550         struct module_kobject *mk;
 551
 552         mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 553         BUG_ON(!mk);
 554
 555         mk->mod = THIS_MODULE;
 556         kobj_set_kset_s(mk, module_subsys);
 557         kobject_set_name(&mk->kobj, name);
 558         kobject_register(&mk->kobj);
 559
 560         /* no need to keep the kobject if no parameter is exported */
 561         if (!param_sysfs_setup(mk, kparam, num_params, name_skip)) {
 562                 kobject_unregister(&mk->kobj);
 563                 kfree(mk);
 564         }
 565 }
 566
 567 /*
 568  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 569  *
 570  * Add module_parameters to sysfs for "modules" built into the kernel.
 571  *
 572  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 573  * "parameter" name is stored behind a dot in kernel_param->name. So,
 574  * extract the "module" name for all built-in kernel_param-eters,
 575  * and for all who have the same, call kernel_param_sysfs_setup.
 576  */
 577 static void __init param_sysfs_builtin(void)
 578 {
 579         struct kernel_param *kp, *kp_begin = NULL;
 580         unsigned int i, name_len, count = 0;
 581         char modname[MAX_KBUILD_MODNAME + 1] = "";
 582
 583         for (i=0; i < __stop___param - __start___param; i++) {
 584                 char *dot;
 585
 586                 kp = &__start___param[i];
 587
 588                 /* We do not handle args without periods. */
 589                 dot = memchr(kp->name, '.', MAX_KBUILD_MODNAME);
 590                 if (!dot) {
 591                         DEBUGP("couldn't find period in %s\n", kp->name);
 592                         continue;
 593                 }
 594                 name_len = dot - kp->name;
 595
 596                 /* new kbuild_modname? */
 597                 if (strlen(modname) != name_len
 598                     || strncmp(modname, kp->name, name_len) != 0) {
 599                         /* add a new kobject for previous kernel_params. */
 600                         if (count)
 601                                 kernel_param_sysfs_setup(modname,
 602                                                          kp_begin,
 603                                                          count,
 604                                                          strlen(modname)+1);
 605
 606                         strncpy(modname, kp->name, name_len);
 607                         modname[name_len] = '\0';
 608                         count = 0;
 609                         kp_begin = kp;
 610                 }
 611                 count++;
 612         }
 613
 614         /* last kernel_params need to be registered as well */
 615         if (count)
 616                 kernel_param_sysfs_setup(modname, kp_begin, count,
 617                                          strlen(modname)+1);
 618 }
 619
 620
 621 /* module-related sysfs stuff */
 622 #ifdef CONFIG_SYSFS
 623
 624 #define to_module_attr(n) container_of(n, struct module_attribute, attr);
 625 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
 626
 627 static ssize_t module_attr_show(struct kobject *kobj,
 628                                 struct attribute *attr,
 629                                 char *buf)
 630 {
 631         struct module_attribute *attribute;
 632         struct module_kobject *mk;
 633         int ret;
 634
 635         attribute = to_module_attr(attr);
 636         mk = to_module_kobject(kobj);
 637
 638         if (!attribute->show)
 639                 return -EIO;
 640
 641         ret = attribute->show(attribute, mk->mod, buf);
 642
 643         return ret;
 644 }
 645
 646 static ssize_t module_attr_store(struct kobject *kobj,
 647                                 struct attribute *attr,
 648                                 const char *buf, size_t len)
 649 {
 650         struct module_attribute *attribute;
 651         struct module_kobject *mk;
 652         int ret;
 653
 654         attribute = to_module_attr(attr);
 655         mk = to_module_kobject(kobj);
 656
 657         if (!attribute->store)
 658                 return -EIO;
 659
 660         ret = attribute->store(attribute, mk->mod, buf, len);
 661
 662         return ret;
 663 }
 664
 665 static struct sysfs_ops module_sysfs_ops = {
 666         .show = module_attr_show,
 667         .store = module_attr_store,
 668 };
 669
 670 #else
 671 static struct sysfs_ops module_sysfs_ops = {
 672         .show = NULL,
 673         .store = NULL,
 674 };
 675 #endif
 676
 677 static struct kobj_type module_ktype = {
 678         .sysfs_ops =    &module_sysfs_ops,
 679 };
 680
 681 decl_subsys(module, &module_ktype, NULL);
 682
 683 /*
 684  * param_sysfs_init - wrapper for built-in params support
 685  */
 686 static int __init param_sysfs_init(void)
 687 {
 688         subsystem_register(&module_subsys);
 689
 690         param_sysfs_builtin();
 691
 692         return 0;
 693 }
 694 __initcall(param_sysfs_init);
 695
 696 EXPORT_SYMBOL(param_set_byte);
 697 EXPORT_SYMBOL(param_get_byte);
 698 EXPORT_SYMBOL(param_set_short);
 699 EXPORT_SYMBOL(param_get_short);
 700 EXPORT_SYMBOL(param_set_ushort);
 701 EXPORT_SYMBOL(param_get_ushort);
 702 EXPORT_SYMBOL(param_set_int);
 703 EXPORT_SYMBOL(param_get_int);
 704 EXPORT_SYMBOL(param_set_uint);
 705 EXPORT_SYMBOL(param_get_uint);
 706 EXPORT_SYMBOL(param_set_long);
 707 EXPORT_SYMBOL(param_get_long);
 708 EXPORT_SYMBOL(param_set_ulong);
 709 EXPORT_SYMBOL(param_get_ulong);
 710 EXPORT_SYMBOL(param_set_charp);
 711 EXPORT_SYMBOL(param_get_charp);
 712 EXPORT_SYMBOL(param_set_bool);
 713 EXPORT_SYMBOL(param_get_bool);
 714 EXPORT_SYMBOL(param_set_invbool);
 715 EXPORT_SYMBOL(param_get_invbool);
 716 EXPORT_SYMBOL(param_array_set);
 717 EXPORT_SYMBOL(param_array_get);
 718 EXPORT_SYMBOL(param_set_copystring);
 719 EXPORT_SYMBOL(param_get_string);