uci.h

   1 /*
   2  * libuci - Library for the Unified Configuration Interface
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License version 2.1
   7  * as published by the Free Software Foundation
   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
  15 #ifndef __LIBUCI_H
  16 #define __LIBUCI_H
  17
  18 #ifdef __cplusplus
  19 extern "C" {
  20 #endif
  21
  22 #include "uci_config.h"
  23
  24 /*
  25  * you can use these defines to enable debugging behavior for
  26  * apps compiled against libuci:
  27  *
  28  * #define UCI_DEBUG_TYPECAST:
  29  *   enable uci_element typecast checking at run time
  30  *
  31  */
  32
  33 #include <stdbool.h>
  34 #include <setjmp.h>
  35 #include <stdio.h>
  36 #include <stdint.h>
  37
  38 #define UCI_CONFDIR "/etc/config"
  39 #define UCI_SAVEDIR "/tmp/.uci"
  40 #define UCI_DIRMODE 0700
  41 #define UCI_FILEMODE 0600
  42
  43 enum
  44 {
  45         UCI_OK = 0,
  46         UCI_ERR_MEM,
  47         UCI_ERR_INVAL,
  48         UCI_ERR_NOTFOUND,
  49         UCI_ERR_IO,
  50         UCI_ERR_PARSE,
  51         UCI_ERR_DUPLICATE,
  52         UCI_ERR_UNKNOWN,
  53         UCI_ERR_LAST
  54 };
  55
  56 struct uci_list;
  57 struct uci_list
  58 {
  59         struct uci_list *next;
  60         struct uci_list *prev;
  61 };
  62
  63 struct uci_ptr;
  64 struct uci_plugin;
  65 struct uci_hook_ops;
  66 struct uci_element;
  67 struct uci_package;
  68 struct uci_section;
  69 struct uci_option;
  70 struct uci_delta;
  71 struct uci_context;
  72 struct uci_backend;
  73 struct uci_parse_option;
  74 struct uci_parse_context;
  75
  76
  77 /**
  78  * uci_alloc_context: Allocate a new uci context
  79  */
  80 extern struct uci_context *uci_alloc_context(void);
  81
  82 /**
  83  * uci_free_context: Free the uci context including all of its data
  84  */
  85 extern void uci_free_context(struct uci_context *ctx);
  86
  87 /**
  88  * uci_perror: Print the last uci error that occured
  89  * @ctx: uci context
  90  * @str: string to print before the error message
  91  */
  92 extern void uci_perror(struct uci_context *ctx, const char *str);
  93
  94 /**
  95  * uci_geterror: Get an error string for the last uci error
  96  * @ctx: uci context
  97  * @dest: target pointer for the string
  98  * @str: prefix for the error message
  99  *
 100  * Note: string must be freed by the caller
 101  */
 102 extern void uci_get_errorstr(struct uci_context *ctx, char **dest, const char *str);
 103
 104 /**
 105  * uci_import: Import uci config data from a stream
 106  * @ctx: uci context
 107  * @stream: file stream to import from
 108  * @name: (optional) assume the config has the given name
 109  * @package: (optional) store the last parsed config package in this variable
 110  * @single: ignore the 'package' keyword and parse everything into a single package
 111  *
 112  * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
 113  * if 'package' points to a non-null struct pointer, enable delta tracking and merge
 114  */
 115 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
 116
 117 /**
 118  * uci_export: Export one or all uci config packages
 119  * @ctx: uci context
 120  * @stream: output stream
 121  * @package: (optional) uci config package to export
 122  * @header: include the package header
 123  */
 124 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
 125
 126 /**
 127  * uci_load: Parse an uci config file and store it in the uci context
 128  *
 129  * @ctx: uci context
 130  * @name: name of the config file (relative to the config directory)
 131  * @package: store the loaded config package in this variable
 132  */
 133 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
 134
 135 /**
 136  * uci_unload: Unload a config file from the uci context
 137  *
 138  * @ctx: uci context
 139  * @package: pointer to the uci_package struct
 140  */
 141 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
 142
 143 /**
 144  * uci_lookup_ptr: Split an uci tuple string and look up an element tree
 145  * @ctx: uci context
 146  * @ptr: lookup result struct
 147  * @str: uci tuple string to look up
 148  * @extended: allow extended syntax lookup
 149  *
 150  * if extended is set to true, uci_lookup_ptr supports the following
 151  * extended syntax:
 152  *
 153  * Examples:
 154  *   network.@interface[0].ifname ('ifname' option of the first interface section)
 155  *   network.@interface[-1]       (last interface section)
 156  * Note: uci_lookup_ptr will automatically load a config package if necessary
 157  * @str must not be constant, as it will be modified and used for the strings inside @ptr,
 158  * thus it must also be available as long as @ptr is in use.
 159  */
 160 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
 161
 162 /**
 163  * uci_add_section: Add an unnamed section
 164  * @ctx: uci context
 165  * @p: package to add the section to
 166  * @type: section type
 167  * @res: pointer to store a reference to the new section in
 168  */
 169 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
 170
 171 /**
 172  * uci_set: Set an element's value; create the element if necessary
 173  * @ctx: uci context
 174  * @ptr: uci pointer
 175  *
 176  * The updated/created element is stored in ptr->last
 177  */
 178 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
 179
 180 /**
 181  * uci_add_list: Append a string to an element list
 182  * @ctx: uci context
 183  * @ptr: uci pointer (with value)
 184  *
 185  * Note: if the given option already contains a string value,
 186  * it will be converted to an 1-element-list before appending the next element
 187  */
 188 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
 189
 190 /**
 191  * uci_reorder: Reposition a section
 192  * @ctx: uci context
 193  * @s: uci section to reposition
 194  * @pos: new position in the section list
 195  */
 196 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
 197
 198 /**
 199  * uci_rename: Rename an element
 200  * @ctx: uci context
 201  * @ptr: uci pointer (with value)
 202  */
 203 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
 204
 205 /**
 206  * uci_delete: Delete a section or option
 207  * @ctx: uci context
 208  * @ptr: uci pointer
 209  */
 210 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
 211
 212 /**
 213  * uci_save: save change delta for a package
 214  * @ctx: uci context
 215  * @p: uci_package struct
 216  */
 217 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 218
 219 /**
 220  * uci_commit: commit changes to a package
 221  * @ctx: uci context
 222  * @p: uci_package struct pointer
 223  * @overwrite: overwrite existing config data and flush delta
 224  *
 225  * committing may reload the whole uci_package data,
 226  * the supplied pointer is updated accordingly
 227  */
 228 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 229
 230 /**
 231  * uci_list_configs: List available uci config files
 232  * @ctx: uci context
 233  *
 234  * caller is responsible for freeing the allocated memory behind list
 235  */
 236 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 237
 238 /**
 239  * uci_set_savedir: override the default delta save directory
 240  * @ctx: uci context
 241  * @dir: directory name
 242  */
 243 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 244
 245 /**
 246  * uci_set_savedir: override the default config storage directory
 247  * @ctx: uci context
 248  * @dir: directory name
 249  */
 250 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 251
 252 /**
 253  * uci_add_delta_path: add a directory to the search path for change delta files
 254  * @ctx: uci context
 255  * @dir: directory name
 256  *
 257  * This function allows you to add directories, which contain 'overlays'
 258  * for the active config, that will never be committed.
 259  */
 260 extern int uci_add_delta_path(struct uci_context *ctx, const char *dir);
 261
 262 /**
 263  * uci_revert: revert all changes to a config item
 264  * @ctx: uci context
 265  * @ptr: uci pointer
 266  */
 267 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 268
 269 /**
 270  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 271  * @ctx: uci context
 272  * @stream: input stream
 273  * @str: pointer to the current line (use NULL for parsing the next line)
 274  * @result: pointer for the result
 275  */
 276 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 277
 278 /**
 279  * uci_set_backend: change the default backend
 280  * @ctx: uci context
 281  * @name: name of the backend
 282  *
 283  * The default backend is "file", which uses /etc/config for config storage
 284  */
 285 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 286
 287 /**
 288  * uci_validate_text: validate a value string for uci options
 289  * @str: value
 290  *
 291  * this function checks whether a given string is acceptable as value
 292  * for uci options
 293  */
 294 extern bool uci_validate_text(const char *str);
 295
 296
 297 /**
 298  * uci_add_hook: add a uci hook
 299  * @ctx: uci context
 300  * @ops: uci hook ops
 301  *
 302  * NB: allocated and freed by the caller
 303  */
 304 extern int uci_add_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 305
 306 /**
 307  * uci_remove_hook: remove a uci hook
 308  * @ctx: uci context
 309  * @ops: uci hook ops
 310  */
 311 extern int uci_remove_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 312
 313 /**
 314  * uci_load_plugin: load an uci plugin
 315  * @ctx: uci context
 316  * @filename: path to the uci plugin
 317  *
 318  * NB: plugin will be unloaded automatically when the context is freed
 319  */
 320 int uci_load_plugin(struct uci_context *ctx, const char *filename);
 321
 322 /**
 323  * uci_load_plugins: load all uci plugins from a directory
 324  * @ctx: uci context
 325  * @pattern: pattern of uci plugin files (optional)
 326  *
 327  * if pattern is NULL, then uci_load_plugins will call uci_load_plugin
 328  * for uci_*.so in <prefix>/lib/
 329  */
 330 int uci_load_plugins(struct uci_context *ctx, const char *pattern);
 331
 332 /**
 333  * uci_parse_ptr: parse a uci string into a uci_ptr
 334  * @ctx: uci context
 335  * @ptr: target data structure
 336  * @str: string to parse
 337  *
 338  * str is modified by this function
 339  */
 340 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str);
 341
 342 /**
 343  * uci_lookup_next: lookup a child element
 344  * @ctx: uci context
 345  * @e: target element pointer
 346  * @list: list of elements
 347  * @name: name of the child element
 348  *
 349  * if parent is NULL, the function looks up the package with the given name
 350  */
 351 int uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name);
 352
 353 /**
 354  * uci_parse_section: look up a set of options
 355  * @s: uci section
 356  * @opts: list of options to look up
 357  * @n_opts: number of options to look up
 358  * @tb: array of pointers to found options
 359  */
 360 void uci_parse_section(struct uci_section *s, const struct uci_parse_option *opts,
 361                        int n_opts, struct uci_option **tb);
 362
 363 /**
 364  * uci_hash_options: build a hash over a list of options
 365  * @tb: list of option pointers
 366  * @n_opts: number of options
 367  */
 368 uint32_t uci_hash_options(struct uci_option **tb, int n_opts);
 369
 370
 371 /* UCI data structures */
 372 enum uci_type {
 373         UCI_TYPE_UNSPEC = 0,
 374         UCI_TYPE_DELTA = 1,
 375         UCI_TYPE_PACKAGE = 2,
 376         UCI_TYPE_SECTION = 3,
 377         UCI_TYPE_OPTION = 4,
 378         UCI_TYPE_PATH = 5,
 379         UCI_TYPE_BACKEND = 6,
 380         UCI_TYPE_ITEM = 7,
 381         UCI_TYPE_HOOK = 8,
 382         UCI_TYPE_PLUGIN = 9,
 383 };
 384
 385 enum uci_option_type {
 386         UCI_TYPE_STRING = 0,
 387         UCI_TYPE_LIST = 1,
 388 };
 389
 390 enum uci_flags {
 391         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 392         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 393         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 394         UCI_FLAG_SAVED_DELTA = (1 << 3), /* store the saved delta in memory as well */
 395 };
 396
 397 struct uci_element
 398 {
 399         struct uci_list list;
 400         enum uci_type type;
 401         char *name;
 402 };
 403
 404 struct uci_backend
 405 {
 406         struct uci_element e;
 407         char **(*list_configs)(struct uci_context *ctx);
 408         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 409         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 410
 411         /* private: */
 412         const void *ptr;
 413         void *priv;
 414 };
 415
 416 struct uci_context
 417 {
 418         /* list of config packages */
 419         struct uci_list root;
 420
 421         /* parser context, use for error handling only */
 422         struct uci_parse_context *pctx;
 423
 424         /* backend for import and export */
 425         struct uci_backend *backend;
 426         struct uci_list backends;
 427
 428         /* uci runtime flags */
 429         enum uci_flags flags;
 430
 431         char *confdir;
 432         char *savedir;
 433
 434         /* search path for delta files */
 435         struct uci_list delta_path;
 436
 437         /* private: */
 438         int err;
 439         const char *func;
 440         jmp_buf trap;
 441         bool internal, nested;
 442         char *buf;
 443         int bufsz;
 444
 445         struct uci_list hooks;
 446         struct uci_list plugins;
 447 };
 448
 449 struct uci_package
 450 {
 451         struct uci_element e;
 452         struct uci_list sections;
 453         struct uci_context *ctx;
 454         bool has_delta;
 455         char *path;
 456
 457         /* private: */
 458         struct uci_backend *backend;
 459         void *priv;
 460         int n_section;
 461         struct uci_list delta;
 462         struct uci_list saved_delta;
 463 };
 464
 465 struct uci_section
 466 {
 467         struct uci_element e;
 468         struct uci_list options;
 469         struct uci_package *package;
 470         bool anonymous;
 471         char *type;
 472 };
 473
 474 struct uci_option
 475 {
 476         struct uci_element e;
 477         struct uci_section *section;
 478         enum uci_option_type type;
 479         union {
 480                 struct uci_list list;
 481                 char *string;
 482         } v;
 483 };
 484
 485 enum uci_command {
 486         UCI_CMD_ADD,
 487         UCI_CMD_REMOVE,
 488         UCI_CMD_CHANGE,
 489         UCI_CMD_RENAME,
 490         UCI_CMD_REORDER,
 491         UCI_CMD_LIST_ADD,
 492 };
 493
 494 struct uci_delta
 495 {
 496         struct uci_element e;
 497         enum uci_command cmd;
 498         char *section;
 499         char *value;
 500 };
 501
 502 struct uci_ptr
 503 {
 504         enum uci_type target;
 505         enum {
 506                 UCI_LOOKUP_DONE =     (1 << 0),
 507                 UCI_LOOKUP_COMPLETE = (1 << 1),
 508                 UCI_LOOKUP_EXTENDED = (1 << 2),
 509         } flags;
 510
 511         struct uci_package *p;
 512         struct uci_section *s;
 513         struct uci_option *o;
 514         struct uci_element *last;
 515
 516         const char *package;
 517         const char *section;
 518         const char *option;
 519         const char *value;
 520 };
 521
 522 struct uci_hook_ops
 523 {
 524         void (*load)(const struct uci_hook_ops *ops, struct uci_package *p);
 525         void (*set)(const struct uci_hook_ops *ops, struct uci_package *p, struct uci_delta *e);
 526 };
 527
 528 struct uci_hook
 529 {
 530         struct uci_element e;
 531         const struct uci_hook_ops *ops;
 532 };
 533
 534 struct uci_plugin_ops
 535 {
 536         int (*attach)(struct uci_context *ctx);
 537         void (*detach)(struct uci_context *ctx);
 538 };
 539
 540 struct uci_plugin
 541 {
 542         struct uci_element e;
 543         const struct uci_plugin_ops *ops;
 544         void *dlh;
 545 };
 546
 547 struct uci_parse_option {
 548         const char *name;
 549         enum uci_option_type type;
 550 };
 551
 552
 553 /* linked list handling */
 554 #ifndef offsetof
 555 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 556 #endif
 557
 558 /**
 559  * container_of - cast a member of a structure out to the containing structure
 560  * @ptr:    the pointer to the member.
 561  * @type:   the type of the container struct this is embedded in.
 562  * @member: the name of the member within the struct.
 563  */
 564 #ifndef container_of
 565 #define container_of(ptr, type, member) \
 566         ((type *) ((char *)ptr - offsetof(type,member)))
 567 #endif
 568
 569
 570 /**
 571  * uci_list_entry: casts an uci_list pointer to the containing struct.
 572  * @_type: config, section or option
 573  * @_ptr: pointer to the uci_list struct
 574  */
 575 #define list_to_element(ptr) \
 576         container_of(ptr, struct uci_element, list)
 577
 578 /**
 579  * uci_foreach_entry: loop through a list of uci elements
 580  * @_list: pointer to the uci_list struct
 581  * @_ptr: iteration variable, struct uci_element
 582  *
 583  * use like a for loop, e.g:
 584  *   uci_foreach(&list, p) {
 585  *      ...
 586  *   }
 587  */
 588 #define uci_foreach_element(_list, _ptr)                \
 589         for(_ptr = list_to_element((_list)->next);      \
 590                 &_ptr->list != (_list);                 \
 591                 _ptr = list_to_element(_ptr->list.next))
 592
 593 /**
 594  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 595  * @_list: pointer to the uci_list struct
 596  * @_tmp: temporary variable, struct uci_element *
 597  * @_ptr: iteration variable, struct uci_element *
 598  *
 599  * use like a for loop, e.g:
 600  *   uci_foreach(&list, p) {
 601  *      ...
 602  *   }
 603  */
 604 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 605         for(_ptr = list_to_element((_list)->next),              \
 606                 _tmp = list_to_element(_ptr->list.next);        \
 607                 &_ptr->list != (_list);                 \
 608                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 609
 610 /**
 611  * uci_list_empty: returns true if a list is empty
 612  * @list: list head
 613  */
 614 #define uci_list_empty(list) ((list)->next == (list))
 615
 616 /* wrappers for dynamic type handling */
 617 #define uci_type_backend UCI_TYPE_BACKEND
 618 #define uci_type_delta UCI_TYPE_DELTA
 619 #define uci_type_package UCI_TYPE_PACKAGE
 620 #define uci_type_section UCI_TYPE_SECTION
 621 #define uci_type_option UCI_TYPE_OPTION
 622 #define uci_type_hook UCI_TYPE_HOOK
 623 #define uci_type_plugin UCI_TYPE_PLUGIN
 624
 625 /* element typecasting */
 626 #ifdef UCI_DEBUG_TYPECAST
 627 static const char *uci_typestr[] = {
 628         [uci_type_backend] = "backend",
 629         [uci_type_delta] = "delta",
 630         [uci_type_package] = "package",
 631         [uci_type_section] = "section",
 632         [uci_type_option] = "option",
 633         [uci_type_hook] = "hook",
 634         [uci_type_plugin] = "plugin",
 635 };
 636
 637 static void uci_typecast_error(int from, int to)
 638 {
 639         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 640 }
 641
 642 #define BUILD_CAST(_type) \
 643         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 644         { \
 645                 if (e->type != uci_type_ ## _type) { \
 646                         uci_typecast_error(e->type, uci_type_ ## _type); \
 647                 } \
 648                 return (struct uci_ ## _type *) e; \
 649         }
 650
 651 BUILD_CAST(backend)
 652 BUILD_CAST(delta)
 653 BUILD_CAST(package)
 654 BUILD_CAST(section)
 655 BUILD_CAST(option)
 656 BUILD_CAST(hook)
 657 BUILD_CAST(plugin)
 658
 659 #else
 660 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 661 #define uci_to_delta(ptr) container_of(ptr, struct uci_delta, e)
 662 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 663 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 664 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 665 #define uci_to_hook(ptr)    container_of(ptr, struct uci_hook, e)
 666 #define uci_to_plugin(ptr)  container_of(ptr, struct uci_plugin, e)
 667 #endif
 668
 669 /**
 670  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 671  * @ctx: uci context
 672  * @type: {package,section,option}
 673  * @name: string containing the name of the element
 674  * @datasize: additional buffer size to reserve at the end of the struct
 675  */
 676 #define uci_alloc_element(ctx, type, name, datasize) \
 677         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 678
 679 #define uci_dataptr(ptr) \
 680         (((char *) ptr) + sizeof(*ptr))
 681
 682 /**
 683  * uci_lookup_package: look up a package
 684  * @ctx: uci context
 685  * @name: name of the package
 686  */
 687 static inline struct uci_package *
 688 uci_lookup_package(struct uci_context *ctx, const char *name)
 689 {
 690         struct uci_element *e = NULL;
 691         if (uci_lookup_next(ctx, &e, &ctx->root, name) == 0)
 692                 return uci_to_package(e);
 693         else
 694                 return NULL;
 695 }
 696
 697 /**
 698  * uci_lookup_section: look up a section
 699  * @ctx: uci context
 700  * @p: package that the section belongs to
 701  * @name: name of the section
 702  */
 703 static inline struct uci_section *
 704 uci_lookup_section(struct uci_context *ctx, struct uci_package *p, const char *name)
 705 {
 706         struct uci_element *e = NULL;
 707         if (uci_lookup_next(ctx, &e, &p->sections, name) == 0)
 708                 return uci_to_section(e);
 709         else
 710                 return NULL;
 711 }
 712
 713 /**
 714  * uci_lookup_option: look up an option
 715  * @ctx: uci context
 716  * @section: section that the option belongs to
 717  * @name: name of the option
 718  */
 719 static inline struct uci_option *
 720 uci_lookup_option(struct uci_context *ctx, struct uci_section *s, const char *name)
 721 {
 722         struct uci_element *e = NULL;
 723         if (uci_lookup_next(ctx, &e, &s->options, name) == 0)
 724                 return uci_to_option(e);
 725         else
 726                 return NULL;
 727 }
 728
 729 static inline const char *
 730 uci_lookup_option_string(struct uci_context *ctx, struct uci_section *s, const char *name)
 731 {
 732         struct uci_option *o;
 733
 734         o = uci_lookup_option(ctx, s, name);
 735         if (!o || o->type != UCI_TYPE_STRING)
 736                 return NULL;
 737
 738         return o->v.string;
 739 }
 740
 741 #ifdef __cplusplus
 742 }
 743 #endif
 744
 745 #endif