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