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