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/moduleparam.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/module.h>
  23
  24 #if 0
  25 #define DEBUGP printk
  26 #else
  27 #define DEBUGP(fmt, a...)
  28 #endif
  29
  30 static inline int dash2underscore(char c)
  31 {
  32         if (c == '-')
  33                 return '_';
  34         return c;
  35 }
  36
  37 static inline int parameq(const char *input, const char *paramname)
  38 {
  39         unsigned int i;
  40         for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
  41                 if (input[i] == '\0')
  42                         return 1;
  43         return 0;
  44 }
  45
  46 static int parse_one(char *param,
  47                      char *val,
  48                      struct kernel_param *params,
  49                      unsigned num_params,
  50                      int (*handle_unknown)(char *param, char *val))
  51 {
  52         unsigned int i;
  53
  54         /* Find parameter */
  55         for (i = 0; i < num_params; i++) {
  56                 if (parameq(param, params[i].name)) {
  57                         DEBUGP("They are equal!  Calling %p\n",
  58                                params[i].set);
  59                         return params[i].set(val, &params[i]);
  60                 }
  61         }
  62
  63         if (handle_unknown) {
  64                 DEBUGP("Unknown argument: calling %p\n", handle_unknown);
  65                 return handle_unknown(param, val);
  66         }
  67
  68         DEBUGP("Unknown argument `%s'\n", param);
  69         return -ENOENT;
  70 }
  71
  72 /* You can use " around spaces, but can't escape ". */
  73 /* Hyphens and underscores equivalent in parameter names. */
  74 static char *next_arg(char *args, char **param, char **val)
  75 {
  76         unsigned int i, equals = 0;
  77         int in_quote = 0;
  78
  79         /* Chew any extra spaces */
  80         while (*args == ' ') args++;
  81
  82         for (i = 0; args[i]; i++) {
  83                 if (args[i] == ' ' && !in_quote)
  84                         break;
  85                 if (equals == 0) {
  86                         if (args[i] == '=')
  87                                 equals = i;
  88                 }
  89                 if (args[i] == '"')
  90                         in_quote = !in_quote;
  91         }
  92
  93         *param = args;
  94         if (!equals)
  95                 *val = NULL;
  96         else {
  97                 args[equals] = '\0';
  98                 *val = args + equals + 1;
  99         }
 100
 101         if (args[i]) {
 102                 args[i] = '\0';
 103                 return args + i + 1;
 104         } else
 105                 return args + i;
 106 }
 107
 108 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 109 int parse_args(const char *name,
 110                char *args,
 111                struct kernel_param *params,
 112                unsigned num,
 113                int (*unknown)(char *param, char *val))
 114 {
 115         char *param, *val;
 116
 117         DEBUGP("Parsing ARGS: %s\n", args);
 118
 119         while (*args) {
 120                 int ret;
 121
 122                 args = next_arg(args, &param, &val);
 123                 ret = parse_one(param, val, params, num, unknown);
 124                 switch (ret) {
 125                 case -ENOENT:
 126                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 127                                name, param);
 128                         return ret;
 129                 case -ENOSPC:
 130                         printk(KERN_ERR
 131                                "%s: `%s' too large for parameter `%s'\n",
 132                                name, val ?: "", param);
 133                         return ret;
 134                 case 0:
 135                         break;
 136                 default:
 137                         printk(KERN_ERR
 138                                "%s: `%s' invalid for parameter `%s'\n",
 139                                name, val ?: "", param);
 140                         return ret;
 141                 }
 142         }
 143
 144         /* All parsed OK. */
 145         return 0;
 146 }
 147
 148 /* Lazy bastard, eh? */
 149 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 150         int param_set_##name(const char *val, struct kernel_param *kp)  \
 151         {                                                               \
 152                 char *endp;                                             \
 153                 tmptype l;                                              \
 154                                                                         \
 155                 if (!val) return -EINVAL;                               \
 156                 l = strtolfn(val, &endp, 0);                            \
 157                 if (endp == val || *endp || ((type)l != l))             \
 158                         return -EINVAL;                                 \
 159                 *((type *)kp->arg) = l;                                 \
 160                 return 0;                                               \
 161         }                                                               \
 162         int param_get_##name(char *buffer, struct kernel_param *kp)     \
 163         {                                                               \
 164                 return sprintf(buffer, format, *((type *)kp->arg));     \
 165         }
 166
 167 STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
 168 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", long, simple_strtol);
 169 STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
 170 STANDARD_PARAM_DEF(uint, unsigned int, "%u", long, simple_strtol);
 171 STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
 172 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);
 173
 174 int param_set_charp(const char *val, struct kernel_param *kp)
 175 {
 176         if (!val) {
 177                 printk(KERN_ERR "%s: string parameter expected\n",
 178                        kp->name);
 179                 return -EINVAL;
 180         }
 181
 182         if (strlen(val) > 1024) {
 183                 printk(KERN_ERR "%s: string parameter too long\n",
 184                        kp->name);
 185                 return -ENOSPC;
 186         }
 187
 188         *(char **)kp->arg = (char *)val;
 189         return 0;
 190 }
 191
 192 int param_get_charp(char *buffer, struct kernel_param *kp)
 193 {
 194         return sprintf(buffer, "%s", *((char **)kp->arg));
 195 }
 196
 197 int param_set_bool(const char *val, struct kernel_param *kp)
 198 {
 199         /* No equals means "set"... */
 200         if (!val) val = "1";
 201
 202         /* One of =[yYnN01] */
 203         switch (val[0]) {
 204         case 'y': case 'Y': case '1':
 205                 *(int *)kp->arg = 1;
 206                 return 0;
 207         case 'n': case 'N': case '0':
 208                 *(int *)kp->arg = 0;
 209                 return 0;
 210         }
 211         return -EINVAL;
 212 }
 213
 214 int param_get_bool(char *buffer, struct kernel_param *kp)
 215 {
 216         /* Y and N chosen as being relatively non-coder friendly */
 217         return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
 218 }
 219
 220 int param_set_invbool(const char *val, struct kernel_param *kp)
 221 {
 222         int boolval, ret;
 223         struct kernel_param dummy = { .arg = &boolval };
 224
 225         ret = param_set_bool(val, &dummy);
 226         if (ret == 0)
 227                 *(int *)kp->arg = !boolval;
 228         return ret;
 229 }
 230
 231 int param_get_invbool(char *buffer, struct kernel_param *kp)
 232 {
 233         int val;
 234         struct kernel_param dummy = { .arg = &val };
 235
 236         val = !*(int *)kp->arg;
 237         return param_get_bool(buffer, &dummy);
 238 }
 239
 240 /* We cheat here and temporarily mangle the string. */
 241 int param_array(const char *name,
 242                 const char *val,
 243                 unsigned int min, unsigned int max,
 244                 void *elem, int elemsize,
 245                 int (*set)(const char *, struct kernel_param *kp))
 246 {
 247         int ret;
 248         unsigned int count = 0;
 249         struct kernel_param kp;
 250         char save;
 251
 252         /* Get the name right for errors. */
 253         kp.name = name;
 254         kp.arg = elem;
 255
 256         /* No equals sign? */
 257         if (!val) {
 258                 printk(KERN_ERR "%s: expects arguments\n", name);
 259                 return -EINVAL;
 260         }
 261
 262         /* We expect a comma-separated list of values. */
 263         do {
 264                 int len;
 265
 266                 if (count > max) {
 267                         printk(KERN_ERR "%s: can only take %i arguments\n",
 268                                name, max);
 269                         return -EINVAL;
 270                 }
 271                 len = strcspn(val, ",");
 272
 273                 /* nul-terminate and parse */
 274                 save = val[len];
 275                 ((char *)val)[len] = '\0';
 276                 ret = set(val, &kp);
 277
 278                 if (ret != 0)
 279                         return ret;
 280                 kp.arg += elemsize;
 281                 val += len+1;
 282                 count++;
 283         } while (save == ',');
 284
 285         if (count < min) {
 286                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 287                        name, min);
 288                 return -EINVAL;
 289         }
 290         return 0;
 291 }
 292
 293 /* First two elements are the max and min array length (which don't change) */
 294 int param_set_intarray(const char *val, struct kernel_param *kp)
 295 {
 296         int *array;
 297
 298         /* Grab min and max as first two elements */
 299         array = kp->arg;
 300         return param_array(kp->name, val, array[0], array[1], &array[2],
 301                            sizeof(int), param_set_int);
 302 }
 303
 304 int param_get_intarray(char *buffer, struct kernel_param *kp)
 305 {
 306         int max;
 307         int *array;
 308         unsigned int i;
 309
 310         array = kp->arg;
 311         max = array[1];
 312
 313         for (i = 2; i < max + 2; i++)
 314                 sprintf(buffer, "%s%i", i > 2 ? "," : "", array[i]);
 315         return strlen(buffer);
 316 }
 317
 318 int param_set_copystring(const char *val, struct kernel_param *kp)
 319 {
 320         struct kparam_string *kps = kp->arg;
 321
 322         if (strlen(val)+1 > kps->maxlen) {
 323                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 324                        kp->name, kps->maxlen-1);
 325                 return -ENOSPC;
 326         }
 327         strcpy(kps->string, val);
 328         return 0;
 329 }
 330
 331 EXPORT_SYMBOL(param_set_short);
 332 EXPORT_SYMBOL(param_get_short);
 333 EXPORT_SYMBOL(param_set_ushort);
 334 EXPORT_SYMBOL(param_get_ushort);
 335 EXPORT_SYMBOL(param_set_int);
 336 EXPORT_SYMBOL(param_get_int);
 337 EXPORT_SYMBOL(param_set_uint);
 338 EXPORT_SYMBOL(param_get_uint);
 339 EXPORT_SYMBOL(param_set_long);
 340 EXPORT_SYMBOL(param_get_long);
 341 EXPORT_SYMBOL(param_set_ulong);
 342 EXPORT_SYMBOL(param_get_ulong);
 343 EXPORT_SYMBOL(param_set_charp);
 344 EXPORT_SYMBOL(param_get_charp);
 345 EXPORT_SYMBOL(param_set_bool);
 346 EXPORT_SYMBOL(param_get_bool);
 347 EXPORT_SYMBOL(param_set_invbool);
 348 EXPORT_SYMBOL(param_get_invbool);
 349 EXPORT_SYMBOL(param_set_intarray);
 350 EXPORT_SYMBOL(param_get_intarray);
 351 EXPORT_SYMBOL(param_set_copystring);