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                 /* Don't include quotes in value. */
 101                 if (**val == '"') {
 102                         (*val)++;
 103                         if (args[i-1] == '"')
 104                                 args[i-1] = '\0';
 105                 }
 106         }
 107
 108         if (args[i]) {
 109                 args[i] = '\0';
 110                 return args + i + 1;
 111         } else
 112                 return args + i;
 113 }
 114
 115 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 116 int parse_args(const char *name,
 117                char *args,
 118                struct kernel_param *params,
 119                unsigned num,
 120                int (*unknown)(char *param, char *val))
 121 {
 122         char *param, *val;
 123
 124         DEBUGP("Parsing ARGS: %s\n", args);
 125
 126         while (*args) {
 127                 int ret;
 128
 129                 args = next_arg(args, &param, &val);
 130                 ret = parse_one(param, val, params, num, unknown);
 131                 switch (ret) {
 132                 case -ENOENT:
 133                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 134                                name, param);
 135                         return ret;
 136                 case -ENOSPC:
 137                         printk(KERN_ERR
 138                                "%s: `%s' too large for parameter `%s'\n",
 139                                name, val ?: "", param);
 140                         return ret;
 141                 case 0:
 142                         break;
 143                 default:
 144                         printk(KERN_ERR
 145                                "%s: `%s' invalid for parameter `%s'\n",
 146                                name, val ?: "", param);
 147                         return ret;
 148                 }
 149         }
 150
 151         /* All parsed OK. */
 152         return 0;
 153 }
 154
 155 /* Lazy bastard, eh? */
 156 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 157         int param_set_##name(const char *val, struct kernel_param *kp)  \
 158         {                                                               \
 159                 char *endp;                                             \
 160                 tmptype l;                                              \
 161                                                                         \
 162                 if (!val) return -EINVAL;                               \
 163                 l = strtolfn(val, &endp, 0);                            \
 164                 if (endp == val || ((type)l != l))                      \
 165                         return -EINVAL;                                 \
 166                 *((type *)kp->arg) = l;                                 \
 167                 return 0;                                               \
 168         }                                                               \
 169         int param_get_##name(char *buffer, struct kernel_param *kp)     \
 170         {                                                               \
 171                 return sprintf(buffer, format, *((type *)kp->arg));     \
 172         }
 173
 174 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, simple_strtoul);
 175 STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
 176 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, simple_strtoul);
 177 STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
 178 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, simple_strtoul);
 179 STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
 180 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);
 181
 182 int param_set_charp(const char *val, struct kernel_param *kp)
 183 {
 184         if (!val) {
 185                 printk(KERN_ERR "%s: string parameter expected\n",
 186                        kp->name);
 187                 return -EINVAL;
 188         }
 189
 190         if (strlen(val) > 1024) {
 191                 printk(KERN_ERR "%s: string parameter too long\n",
 192                        kp->name);
 193                 return -ENOSPC;
 194         }
 195
 196         *(char **)kp->arg = (char *)val;
 197         return 0;
 198 }
 199
 200 int param_get_charp(char *buffer, struct kernel_param *kp)
 201 {
 202         return sprintf(buffer, "%s", *((char **)kp->arg));
 203 }
 204
 205 int param_set_bool(const char *val, struct kernel_param *kp)
 206 {
 207         /* No equals means "set"... */
 208         if (!val) val = "1";
 209
 210         /* One of =[yYnN01] */
 211         switch (val[0]) {
 212         case 'y': case 'Y': case '1':
 213                 *(int *)kp->arg = 1;
 214                 return 0;
 215         case 'n': case 'N': case '0':
 216                 *(int *)kp->arg = 0;
 217                 return 0;
 218         }
 219         return -EINVAL;
 220 }
 221
 222 int param_get_bool(char *buffer, struct kernel_param *kp)
 223 {
 224         /* Y and N chosen as being relatively non-coder friendly */
 225         return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
 226 }
 227
 228 int param_set_invbool(const char *val, struct kernel_param *kp)
 229 {
 230         int boolval, ret;
 231         struct kernel_param dummy = { .arg = &boolval };
 232
 233         ret = param_set_bool(val, &dummy);
 234         if (ret == 0)
 235                 *(int *)kp->arg = !boolval;
 236         return ret;
 237 }
 238
 239 int param_get_invbool(char *buffer, struct kernel_param *kp)
 240 {
 241         int val;
 242         struct kernel_param dummy = { .arg = &val };
 243
 244         val = !*(int *)kp->arg;
 245         return param_get_bool(buffer, &dummy);
 246 }
 247
 248 /* We cheat here and temporarily mangle the string. */
 249 int param_array(const char *name,
 250                 const char *val,
 251                 unsigned int min, unsigned int max,
 252                 void *elem, int elemsize,
 253                 int (*set)(const char *, struct kernel_param *kp),
 254                 int *num)
 255 {
 256         int ret;
 257         struct kernel_param kp;
 258         char save;
 259
 260         /* Get the name right for errors. */
 261         kp.name = name;
 262         kp.arg = elem;
 263
 264         /* No equals sign? */
 265         if (!val) {
 266                 printk(KERN_ERR "%s: expects arguments\n", name);
 267                 return -EINVAL;
 268         }
 269
 270         *num = 0;
 271         /* We expect a comma-separated list of values. */
 272         do {
 273                 int len;
 274
 275                 if (*num == max) {
 276                         printk(KERN_ERR "%s: can only take %i arguments\n",
 277                                name, max);
 278                         return -EINVAL;
 279                 }
 280                 len = strcspn(val, ",");
 281
 282                 /* nul-terminate and parse */
 283                 save = val[len];
 284                 ((char *)val)[len] = '\0';
 285                 ret = set(val, &kp);
 286
 287                 if (ret != 0)
 288                         return ret;
 289                 kp.arg += elemsize;
 290                 val += len+1;
 291                 (*num)++;
 292         } while (save == ',');
 293
 294         if (*num < min) {
 295                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 296                        name, min);
 297                 return -EINVAL;
 298         }
 299         return 0;
 300 }
 301
 302 int param_array_set(const char *val, struct kernel_param *kp)
 303 {
 304         struct kparam_array *arr = kp->arg;
 305
 306         return param_array(kp->name, val, 1, arr->max, arr->elem,
 307                            arr->elemsize, arr->set, arr->num);
 308 }
 309
 310 int param_array_get(char *buffer, struct kernel_param *kp)
 311 {
 312         int i, off, ret;
 313         struct kparam_array *arr = kp->arg;
 314         struct kernel_param p;
 315
 316         p = *kp;
 317         for (i = off = 0; i < *arr->num; i++) {
 318                 if (i)
 319                         buffer[off++] = ',';
 320                 p.arg = arr->elem + arr->elemsize * i;
 321                 ret = arr->get(buffer + off, &p);
 322                 if (ret < 0)
 323                         return ret;
 324                 off += ret;
 325         }
 326         buffer[off] = '\0';
 327         return off;
 328 }
 329
 330 int param_set_copystring(const char *val, struct kernel_param *kp)
 331 {
 332         struct kparam_string *kps = kp->arg;
 333
 334         if (strlen(val)+1 > kps->maxlen) {
 335                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 336                        kp->name, kps->maxlen-1);
 337                 return -ENOSPC;
 338         }
 339         strcpy(kps->string, val);
 340         return 0;
 341 }
 342
 343 int param_get_string(char *buffer, struct kernel_param *kp)
 344 {
 345         struct kparam_string *kps = kp->arg;
 346         return strlcpy(buffer, kps->string, kps->maxlen);
 347 }
 348
 349 EXPORT_SYMBOL(param_set_byte);
 350 EXPORT_SYMBOL(param_get_byte);
 351 EXPORT_SYMBOL(param_set_short);
 352 EXPORT_SYMBOL(param_get_short);
 353 EXPORT_SYMBOL(param_set_ushort);
 354 EXPORT_SYMBOL(param_get_ushort);
 355 EXPORT_SYMBOL(param_set_int);
 356 EXPORT_SYMBOL(param_get_int);
 357 EXPORT_SYMBOL(param_set_uint);
 358 EXPORT_SYMBOL(param_get_uint);
 359 EXPORT_SYMBOL(param_set_long);
 360 EXPORT_SYMBOL(param_get_long);
 361 EXPORT_SYMBOL(param_set_ulong);
 362 EXPORT_SYMBOL(param_get_ulong);
 363 EXPORT_SYMBOL(param_set_charp);
 364 EXPORT_SYMBOL(param_get_charp);
 365 EXPORT_SYMBOL(param_set_bool);
 366 EXPORT_SYMBOL(param_get_bool);
 367 EXPORT_SYMBOL(param_set_invbool);
 368 EXPORT_SYMBOL(param_get_invbool);
 369 EXPORT_SYMBOL(param_array_set);
 370 EXPORT_SYMBOL(param_array_get);
 371 EXPORT_SYMBOL(param_set_copystring);
 372 EXPORT_SYMBOL(param_get_string);