env/flags.c

   1 /*
   2  * (C) Copyright 2012
   3  * Joe Hershberger, National Instruments, joe.hershberger@ni.com
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <linux/string.h>
   9 #include <linux/ctype.h>
  10
  11 #ifdef USE_HOSTCC /* Eliminate "ANSI does not permit..." warnings */
  12 #include <stdint.h>
  13 #include <stdio.h>
  14 #include "fw_env_private.h"
  15 #include "fw_env.h"
  16 #include <env_attr.h>
  17 #include <env_flags.h>
  18 #define env_get fw_getenv
  19 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  20 #else
  21 #include <common.h>
  22 #include <environment.h>
  23 #endif
  24
  25 #ifdef CONFIG_CMD_NET
  26 #define ENV_FLAGS_NET_VARTYPE_REPS "im"
  27 #else
  28 #define ENV_FLAGS_NET_VARTYPE_REPS ""
  29 #endif
  30
  31 static const char env_flags_vartype_rep[] = "sdxb" ENV_FLAGS_NET_VARTYPE_REPS;
  32 static const char env_flags_varaccess_rep[] = "aroc";
  33 static const int env_flags_varaccess_mask[] = {
  34         0,
  35         ENV_FLAGS_VARACCESS_PREVENT_DELETE |
  36                 ENV_FLAGS_VARACCESS_PREVENT_CREATE |
  37                 ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
  38         ENV_FLAGS_VARACCESS_PREVENT_DELETE |
  39                 ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
  40         ENV_FLAGS_VARACCESS_PREVENT_DELETE |
  41                 ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR};
  42
  43 #ifdef CONFIG_CMD_ENV_FLAGS
  44 static const char * const env_flags_vartype_names[] = {
  45         "string",
  46         "decimal",
  47         "hexadecimal",
  48         "boolean",
  49 #ifdef CONFIG_CMD_NET
  50         "IP address",
  51         "MAC address",
  52 #endif
  53 };
  54 static const char * const env_flags_varaccess_names[] = {
  55         "any",
  56         "read-only",
  57         "write-once",
  58         "change-default",
  59 };
  60
  61 /*
  62  * Print the whole list of available type flags.
  63  */
  64 void env_flags_print_vartypes(void)
  65 {
  66         enum env_flags_vartype curtype = (enum env_flags_vartype)0;
  67
  68         while (curtype != env_flags_vartype_end) {
  69                 printf("\t%c   -\t%s\n", env_flags_vartype_rep[curtype],
  70                         env_flags_vartype_names[curtype]);
  71                 curtype++;
  72         }
  73 }
  74
  75 /*
  76  * Print the whole list of available access flags.
  77  */
  78 void env_flags_print_varaccess(void)
  79 {
  80         enum env_flags_varaccess curaccess = (enum env_flags_varaccess)0;
  81
  82         while (curaccess != env_flags_varaccess_end) {
  83                 printf("\t%c   -\t%s\n", env_flags_varaccess_rep[curaccess],
  84                         env_flags_varaccess_names[curaccess]);
  85                 curaccess++;
  86         }
  87 }
  88
  89 /*
  90  * Return the name of the type.
  91  */
  92 const char *env_flags_get_vartype_name(enum env_flags_vartype type)
  93 {
  94         return env_flags_vartype_names[type];
  95 }
  96
  97 /*
  98  * Return the name of the access.
  99  */
 100 const char *env_flags_get_varaccess_name(enum env_flags_varaccess access)
 101 {
 102         return env_flags_varaccess_names[access];
 103 }
 104 #endif /* CONFIG_CMD_ENV_FLAGS */
 105
 106 /*
 107  * Parse the flags string from a .flags attribute list into the vartype enum.
 108  */
 109 enum env_flags_vartype env_flags_parse_vartype(const char *flags)
 110 {
 111         char *type;
 112
 113         if (strlen(flags) <= ENV_FLAGS_VARTYPE_LOC)
 114                 return env_flags_vartype_string;
 115
 116         type = strchr(env_flags_vartype_rep,
 117                 flags[ENV_FLAGS_VARTYPE_LOC]);
 118
 119         if (type != NULL)
 120                 return (enum env_flags_vartype)
 121                         (type - &env_flags_vartype_rep[0]);
 122
 123         printf("## Warning: Unknown environment variable type '%c'\n",
 124                 flags[ENV_FLAGS_VARTYPE_LOC]);
 125         return env_flags_vartype_string;
 126 }
 127
 128 /*
 129  * Parse the flags string from a .flags attribute list into the varaccess enum.
 130  */
 131 enum env_flags_varaccess env_flags_parse_varaccess(const char *flags)
 132 {
 133         char *access;
 134
 135         if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
 136                 return env_flags_varaccess_any;
 137
 138         access = strchr(env_flags_varaccess_rep,
 139                 flags[ENV_FLAGS_VARACCESS_LOC]);
 140
 141         if (access != NULL)
 142                 return (enum env_flags_varaccess)
 143                         (access - &env_flags_varaccess_rep[0]);
 144
 145         printf("## Warning: Unknown environment variable access method '%c'\n",
 146                 flags[ENV_FLAGS_VARACCESS_LOC]);
 147         return env_flags_varaccess_any;
 148 }
 149
 150 /*
 151  * Parse the binary flags from a hash table entry into the varaccess enum.
 152  */
 153 enum env_flags_varaccess env_flags_parse_varaccess_from_binflags(int binflags)
 154 {
 155         int i;
 156
 157         for (i = 0; i < ARRAY_SIZE(env_flags_varaccess_mask); i++)
 158                 if (env_flags_varaccess_mask[i] ==
 159                     (binflags & ENV_FLAGS_VARACCESS_BIN_MASK))
 160                         return (enum env_flags_varaccess)i;
 161
 162         printf("Warning: Non-standard access flags. (0x%x)\n",
 163                 binflags & ENV_FLAGS_VARACCESS_BIN_MASK);
 164
 165         return env_flags_varaccess_any;
 166 }
 167
 168 static inline int is_hex_prefix(const char *value)
 169 {
 170         return value[0] == '0' && (value[1] == 'x' || value[1] == 'X');
 171 }
 172
 173 static void skip_num(int hex, const char *value, const char **end,
 174         int max_digits)
 175 {
 176         int i;
 177
 178         if (hex && is_hex_prefix(value))
 179                 value += 2;
 180
 181         for (i = max_digits; i != 0; i--) {
 182                 if (hex && !isxdigit(*value))
 183                         break;
 184                 if (!hex && !isdigit(*value))
 185                         break;
 186                 value++;
 187         }
 188         if (end != NULL)
 189                 *end = value;
 190 }
 191
 192 #ifdef CONFIG_CMD_NET
 193 int eth_validate_ethaddr_str(const char *addr)
 194 {
 195         const char *end;
 196         const char *cur;
 197         int i;
 198
 199         cur = addr;
 200         for (i = 0; i < 6; i++) {
 201                 skip_num(1, cur, &end, 2);
 202                 if (cur == end)
 203                         return -1;
 204                 if (cur + 2 == end && is_hex_prefix(cur))
 205                         return -1;
 206                 if (i != 5 && *end != ':')
 207                         return -1;
 208                 if (i == 5 && *end != '\0')
 209                         return -1;
 210                 cur = end + 1;
 211         }
 212
 213         return 0;
 214 }
 215 #endif
 216
 217 /*
 218  * Based on the declared type enum, validate that the value string complies
 219  * with that format
 220  */
 221 static int _env_flags_validate_type(const char *value,
 222         enum env_flags_vartype type)
 223 {
 224         const char *end;
 225 #ifdef CONFIG_CMD_NET
 226         const char *cur;
 227         int i;
 228 #endif
 229
 230         switch (type) {
 231         case env_flags_vartype_string:
 232                 break;
 233         case env_flags_vartype_decimal:
 234                 skip_num(0, value, &end, -1);
 235                 if (*end != '\0')
 236                         return -1;
 237                 break;
 238         case env_flags_vartype_hex:
 239                 skip_num(1, value, &end, -1);
 240                 if (*end != '\0')
 241                         return -1;
 242                 if (value + 2 == end && is_hex_prefix(value))
 243                         return -1;
 244                 break;
 245         case env_flags_vartype_bool:
 246                 if (value[0] != '1' && value[0] != 'y' && value[0] != 't' &&
 247                     value[0] != 'Y' && value[0] != 'T' &&
 248                     value[0] != '0' && value[0] != 'n' && value[0] != 'f' &&
 249                     value[0] != 'N' && value[0] != 'F')
 250                         return -1;
 251                 if (value[1] != '\0')
 252                         return -1;
 253                 break;
 254 #ifdef CONFIG_CMD_NET
 255         case env_flags_vartype_ipaddr:
 256                 cur = value;
 257                 for (i = 0; i < 4; i++) {
 258                         skip_num(0, cur, &end, 3);
 259                         if (cur == end)
 260                                 return -1;
 261                         if (i != 3 && *end != '.')
 262                                 return -1;
 263                         if (i == 3 && *end != '\0')
 264                                 return -1;
 265                         cur = end + 1;
 266                 }
 267                 break;
 268         case env_flags_vartype_macaddr:
 269                 if (eth_validate_ethaddr_str(value))
 270                         return -1;
 271                 break;
 272 #endif
 273         case env_flags_vartype_end:
 274                 return -1;
 275         }
 276
 277         /* OK */
 278         return 0;
 279 }
 280
 281 /*
 282  * Look for flags in a provided list and failing that the static list
 283  */
 284 static inline int env_flags_lookup(const char *flags_list, const char *name,
 285         char *flags)
 286 {
 287         int ret = 1;
 288
 289         if (!flags)
 290                 /* bad parameter */
 291                 return -1;
 292
 293         /* try the env first */
 294         if (flags_list)
 295                 ret = env_attr_lookup(flags_list, name, flags);
 296
 297         if (ret != 0)
 298                 /* if not found in the env, look in the static list */
 299                 ret = env_attr_lookup(ENV_FLAGS_LIST_STATIC, name, flags);
 300
 301         return ret;
 302 }
 303
 304 #ifdef USE_HOSTCC /* Functions only used from tools/env */
 305 /*
 306  * Look up any flags directly from the .flags variable and the static list
 307  * and convert them to the vartype enum.
 308  */
 309 enum env_flags_vartype env_flags_get_type(const char *name)
 310 {
 311         const char *flags_list = env_get(ENV_FLAGS_VAR);
 312         char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];
 313
 314         if (env_flags_lookup(flags_list, name, flags))
 315                 return env_flags_vartype_string;
 316
 317         if (strlen(flags) <= ENV_FLAGS_VARTYPE_LOC)
 318                 return env_flags_vartype_string;
 319
 320         return env_flags_parse_vartype(flags);
 321 }
 322
 323 /*
 324  * Look up the access of a variable directly from the .flags var.
 325  */
 326 enum env_flags_varaccess env_flags_get_varaccess(const char *name)
 327 {
 328         const char *flags_list = env_get(ENV_FLAGS_VAR);
 329         char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];
 330
 331         if (env_flags_lookup(flags_list, name, flags))
 332                 return env_flags_varaccess_any;
 333
 334         if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
 335                 return env_flags_varaccess_any;
 336
 337         return env_flags_parse_varaccess(flags);
 338 }
 339
 340 /*
 341  * Validate that the proposed new value for "name" is valid according to the
 342  * defined flags for that variable, if any.
 343  */
 344 int env_flags_validate_type(const char *name, const char *value)
 345 {
 346         enum env_flags_vartype type;
 347
 348         if (value == NULL)
 349                 return 0;
 350         type = env_flags_get_type(name);
 351         if (_env_flags_validate_type(value, type) < 0) {
 352                 printf("## Error: flags type check failure for "
 353                         "\"%s\" <= \"%s\" (type: %c)\n",
 354                         name, value, env_flags_vartype_rep[type]);
 355                 return -1;
 356         }
 357         return 0;
 358 }
 359
 360 /*
 361  * Validate that the proposed access to variable "name" is valid according to
 362  * the defined flags for that variable, if any.
 363  */
 364 int env_flags_validate_varaccess(const char *name, int check_mask)
 365 {
 366         enum env_flags_varaccess access;
 367         int access_mask;
 368
 369         access = env_flags_get_varaccess(name);
 370         access_mask = env_flags_varaccess_mask[access];
 371
 372         return (check_mask & access_mask) != 0;
 373 }
 374
 375 /*
 376  * Validate the parameters to "env set" directly
 377  */
 378 int env_flags_validate_env_set_params(char *name, char * const val[], int count)
 379 {
 380         if ((count >= 1) && val[0] != NULL) {
 381                 enum env_flags_vartype type = env_flags_get_type(name);
 382
 383                 /*
 384                  * we don't currently check types that need more than
 385                  * one argument
 386                  */
 387                 if (type != env_flags_vartype_string && count > 1) {
 388                         printf("## Error: too many parameters for setting \"%s\"\n",
 389                                name);
 390                         return -1;
 391                 }
 392                 return env_flags_validate_type(name, val[0]);
 393         }
 394         /* ok */
 395         return 0;
 396 }
 397
 398 #else /* !USE_HOSTCC - Functions only used from lib/hashtable.c */
 399
 400 /*
 401  * Parse the flag charachters from the .flags attribute list into the binary
 402  * form to be stored in the environment entry->flags field.
 403  */
 404 static int env_parse_flags_to_bin(const char *flags)
 405 {
 406         int binflags;
 407
 408         binflags = env_flags_parse_vartype(flags) & ENV_FLAGS_VARTYPE_BIN_MASK;
 409         binflags |= env_flags_varaccess_mask[env_flags_parse_varaccess(flags)];
 410
 411         return binflags;
 412 }
 413
 414 static int first_call = 1;
 415 static const char *flags_list;
 416
 417 /*
 418  * Look for possible flags for a newly added variable
 419  * This is called specifically when the variable did not exist in the hash
 420  * previously, so the blanket update did not find this variable.
 421  */
 422 void env_flags_init(ENTRY *var_entry)
 423 {
 424         const char *var_name = var_entry->key;
 425         char flags[ENV_FLAGS_ATTR_MAX_LEN + 1] = "";
 426         int ret = 1;
 427
 428         if (first_call) {
 429                 flags_list = env_get(ENV_FLAGS_VAR);
 430                 first_call = 0;
 431         }
 432         /* look in the ".flags" and static for a reference to this variable */
 433         ret = env_flags_lookup(flags_list, var_name, flags);
 434
 435         /* if any flags were found, set the binary form to the entry */
 436         if (!ret && strlen(flags))
 437                 var_entry->flags = env_parse_flags_to_bin(flags);
 438 }
 439
 440 /*
 441  * Called on each existing env var prior to the blanket update since removing
 442  * a flag in the flag list should remove its flags.
 443  */
 444 static int clear_flags(ENTRY *entry)
 445 {
 446         entry->flags = 0;
 447
 448         return 0;
 449 }
 450
 451 /*
 452  * Call for each element in the list that defines flags for a variable
 453  */
 454 static int set_flags(const char *name, const char *value, void *priv)
 455 {
 456         ENTRY e, *ep;
 457
 458         e.key   = name;
 459         e.data  = NULL;
 460         e.callback = NULL;
 461         hsearch_r(e, FIND, &ep, &env_htab, 0);
 462
 463         /* does the env variable actually exist? */
 464         if (ep != NULL) {
 465                 /* the flag list is empty, so clear the flags */
 466                 if (value == NULL || strlen(value) == 0)
 467                         ep->flags = 0;
 468                 else
 469                         /* assign the requested flags */
 470                         ep->flags = env_parse_flags_to_bin(value);
 471         }
 472
 473         return 0;
 474 }
 475
 476 static int on_flags(const char *name, const char *value, enum env_op op,
 477         int flags)
 478 {
 479         /* remove all flags */
 480         hwalk_r(&env_htab, clear_flags);
 481
 482         /* configure any static flags */
 483         env_attr_walk(ENV_FLAGS_LIST_STATIC, set_flags, NULL);
 484         /* configure any dynamic flags */
 485         env_attr_walk(value, set_flags, NULL);
 486
 487         return 0;
 488 }
 489 U_BOOT_ENV_CALLBACK(flags, on_flags);
 490
 491 /*
 492  * Perform consistency checking before creating, overwriting, or deleting an
 493  * environment variable. Called as a callback function by hsearch_r() and
 494  * hdelete_r(). Returns 0 in case of success, 1 in case of failure.
 495  * When (flag & H_FORCE) is set, do not print out any error message and force
 496  * overwriting of write-once variables.
 497  */
 498
 499 int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
 500         int flag)
 501 {
 502         const char *name;
 503         const char *oldval = NULL;
 504
 505         if (op != env_op_create)
 506                 oldval = item->data;
 507
 508         name = item->key;
 509
 510         /* Default value for NULL to protect string-manipulating functions */
 511         newval = newval ? : "";
 512
 513         /* validate the value to match the variable type */
 514         if (op != env_op_delete) {
 515                 enum env_flags_vartype type = (enum env_flags_vartype)
 516                         (ENV_FLAGS_VARTYPE_BIN_MASK & item->flags);
 517
 518                 if (_env_flags_validate_type(newval, type) < 0) {
 519                         printf("## Error: flags type check failure for "
 520                                 "\"%s\" <= \"%s\" (type: %c)\n",
 521                                 name, newval, env_flags_vartype_rep[type]);
 522                         return -1;
 523                 }
 524         }
 525
 526         /* check for access permission */
 527 #ifndef CONFIG_ENV_ACCESS_IGNORE_FORCE
 528         if (flag & H_FORCE)
 529                 return 0;
 530 #endif
 531         switch (op) {
 532         case env_op_delete:
 533                 if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_DELETE) {
 534                         printf("## Error: Can't delete \"%s\"\n", name);
 535                         return 1;
 536                 }
 537                 break;
 538         case env_op_overwrite:
 539                 if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_OVERWR) {
 540                         printf("## Error: Can't overwrite \"%s\"\n", name);
 541                         return 1;
 542                 } else if (item->flags &
 543                     ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR) {
 544                         const char *defval = env_get_default(name);
 545
 546                         if (defval == NULL)
 547                                 defval = "";
 548                         printf("oldval: %s  defval: %s\n", oldval, defval);
 549                         if (strcmp(oldval, defval) != 0) {
 550                                 printf("## Error: Can't overwrite \"%s\"\n",
 551                                         name);
 552                                 return 1;
 553                         }
 554                 }
 555                 break;
 556         case env_op_create:
 557                 if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_CREATE) {
 558                         printf("## Error: Can't create \"%s\"\n", name);
 559                         return 1;
 560                 }
 561                 break;
 562         }
 563
 564         return 0;
 565 }
 566
 567 #endif