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