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  * This will also try adding the specified dir to the end of delta pathes.
 257  */
 258 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 259
 260 /**
 261  * uci_set_savedir: override the default config storage directory
 262  * @ctx: uci context
 263  * @dir: directory name
 264  */
 265 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 266
 267 /**
 268  * uci_add_delta_path: add a directory to the search path for change delta files
 269  * @ctx: uci context
 270  * @dir: directory name
 271  *
 272  * This function allows you to add directories, which contain 'overlays'
 273  * for the active config, that will never be committed.
 274  *
 275  * Adding a duplicate directory will cause UCI_ERR_DUPLICATE be returned.
 276  */
 277 extern int uci_add_delta_path(struct uci_context *ctx, const char *dir);
 278
 279 /**
 280  * uci_revert: revert all changes to a config item
 281  * @ctx: uci context
 282  * @ptr: uci pointer
 283  */
 284 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 285
 286 /**
 287  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 288  * @ctx: uci context
 289  * @stream: input stream
 290  * @str: pointer to the current line (use NULL for parsing the next line)
 291  * @result: pointer for the result
 292  */
 293 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 294
 295 /**
 296  * uci_set_backend: change the default backend
 297  * @ctx: uci context
 298  * @name: name of the backend
 299  *
 300  * The default backend is "file", which uses /etc/config for config storage
 301  */
 302 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 303
 304 /**
 305  * uci_validate_text: validate a value string for uci options
 306  * @str: value
 307  *
 308  * this function checks whether a given string is acceptable as value
 309  * for uci options
 310  */
 311 extern bool uci_validate_text(const char *str);
 312
 313 /**
 314  * uci_parse_ptr: parse a uci string into a uci_ptr
 315  * @ctx: uci context
 316  * @ptr: target data structure
 317  * @str: string to parse
 318  *
 319  * str is modified by this function
 320  */
 321 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str);
 322
 323 /**
 324  * uci_lookup_next: lookup a child element
 325  * @ctx: uci context
 326  * @e: target element pointer
 327  * @list: list of elements
 328  * @name: name of the child element
 329  *
 330  * if parent is NULL, the function looks up the package with the given name
 331  */
 332 int uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name);
 333
 334 /**
 335  * uci_parse_section: look up a set of options
 336  * @s: uci section
 337  * @opts: list of options to look up
 338  * @n_opts: number of options to look up
 339  * @tb: array of pointers to found options
 340  */
 341 void uci_parse_section(struct uci_section *s, const struct uci_parse_option *opts,
 342                        int n_opts, struct uci_option **tb);
 343
 344 /**
 345  * uci_hash_options: build a hash over a list of options
 346  * @tb: list of option pointers
 347  * @n_opts: number of options
 348  */
 349 uint32_t uci_hash_options(struct uci_option **tb, int n_opts);
 350
 351
 352 /* UCI data structures */
 353 enum uci_type {
 354         UCI_TYPE_UNSPEC = 0,
 355         UCI_TYPE_DELTA = 1,
 356         UCI_TYPE_PACKAGE = 2,
 357         UCI_TYPE_SECTION = 3,
 358         UCI_TYPE_OPTION = 4,
 359         UCI_TYPE_PATH = 5,
 360         UCI_TYPE_BACKEND = 6,
 361         UCI_TYPE_ITEM = 7,
 362         UCI_TYPE_HOOK = 8,
 363 };
 364
 365 enum uci_option_type {
 366         UCI_TYPE_STRING = 0,
 367         UCI_TYPE_LIST = 1,
 368 };
 369
 370 enum uci_flags {
 371         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 372         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 373         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 374         UCI_FLAG_SAVED_DELTA = (1 << 3), /* store the saved delta in memory as well */
 375 };
 376
 377 struct uci_element
 378 {
 379         struct uci_list list;
 380         enum uci_type type;
 381         char *name;
 382 };
 383
 384 struct uci_backend
 385 {
 386         struct uci_element e;
 387         char **(*list_configs)(struct uci_context *ctx);
 388         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 389         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 390
 391         /* private: */
 392         const void *ptr;
 393         void *priv;
 394 };
 395
 396 struct uci_context
 397 {
 398         /* list of config packages */
 399         struct uci_list root;
 400
 401         /* parser context, use for error handling only */
 402         struct uci_parse_context *pctx;
 403
 404         /* backend for import and export */
 405         struct uci_backend *backend;
 406         struct uci_list backends;
 407
 408         /* uci runtime flags */
 409         enum uci_flags flags;
 410
 411         char *confdir;
 412         char *savedir;
 413
 414         /* search path for delta files */
 415         struct uci_list delta_path;
 416
 417         /* private: */
 418         int err;
 419         const char *func;
 420         jmp_buf trap;
 421         bool internal, nested;
 422         char *buf;
 423         int bufsz;
 424 };
 425
 426 struct uci_package
 427 {
 428         struct uci_element e;
 429         struct uci_list sections;
 430         struct uci_context *ctx;
 431         bool has_delta;
 432         char *path;
 433
 434         /* private: */
 435         struct uci_backend *backend;
 436         void *priv;
 437         int n_section;
 438         struct uci_list delta;
 439         struct uci_list saved_delta;
 440 };
 441
 442 struct uci_section
 443 {
 444         struct uci_element e;
 445         struct uci_list options;
 446         struct uci_package *package;
 447         bool anonymous;
 448         char *type;
 449 };
 450
 451 struct uci_option
 452 {
 453         struct uci_element e;
 454         struct uci_section *section;
 455         enum uci_option_type type;
 456         union {
 457                 struct uci_list list;
 458                 char *string;
 459         } v;
 460 };
 461
 462 /*
 463  * UCI_CMD_ADD is used for anonymous sections or list values
 464  */
 465 enum uci_command {
 466         UCI_CMD_ADD,
 467         UCI_CMD_REMOVE,
 468         UCI_CMD_CHANGE,
 469         UCI_CMD_RENAME,
 470         UCI_CMD_REORDER,
 471         UCI_CMD_LIST_ADD,
 472         UCI_CMD_LIST_DEL,
 473         __UCI_CMD_MAX,
 474         __UCI_CMD_LAST = __UCI_CMD_MAX - 1
 475 };
 476 extern char const uci_command_char[];
 477
 478 struct uci_delta
 479 {
 480         struct uci_element e;
 481         enum uci_command cmd;
 482         char *section;
 483         char *value;
 484 };
 485
 486 struct uci_ptr
 487 {
 488         enum uci_type target;
 489         enum {
 490                 UCI_LOOKUP_DONE =     (1 << 0),
 491                 UCI_LOOKUP_COMPLETE = (1 << 1),
 492                 UCI_LOOKUP_EXTENDED = (1 << 2),
 493         } flags;
 494
 495         struct uci_package *p;
 496         struct uci_section *s;
 497         struct uci_option *o;
 498         struct uci_element *last;
 499
 500         const char *package;
 501         const char *section;
 502         const char *option;
 503         const char *value;
 504 };
 505
 506 struct uci_parse_option {
 507         const char *name;
 508         enum uci_option_type type;
 509 };
 510
 511
 512 /* linked list handling */
 513 #ifndef offsetof
 514 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 515 #endif
 516
 517 /**
 518  * container_of - cast a member of a structure out to the containing structure
 519  * @ptr:    the pointer to the member.
 520  * @type:   the type of the container struct this is embedded in.
 521  * @member: the name of the member within the struct.
 522  */
 523 #ifndef container_of
 524 #define container_of(ptr, type, member) \
 525         ((type *) ((char *)ptr - offsetof(type,member)))
 526 #endif
 527
 528
 529 /**
 530  * uci_list_entry: casts an uci_list pointer to the containing struct.
 531  * @_type: config, section or option
 532  * @_ptr: pointer to the uci_list struct
 533  */
 534 #define list_to_element(ptr) \
 535         container_of(ptr, struct uci_element, list)
 536
 537 /**
 538  * uci_foreach_entry: loop through a list of uci elements
 539  * @_list: pointer to the uci_list struct
 540  * @_ptr: iteration variable, struct uci_element
 541  *
 542  * use like a for loop, e.g:
 543  *   uci_foreach(&list, p) {
 544  *      ...
 545  *   }
 546  */
 547 #define uci_foreach_element(_list, _ptr)                \
 548         for(_ptr = list_to_element((_list)->next);      \
 549                 &_ptr->list != (_list);                 \
 550                 _ptr = list_to_element(_ptr->list.next))
 551
 552 /**
 553  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 554  * @_list: pointer to the uci_list struct
 555  * @_tmp: temporary variable, struct uci_element *
 556  * @_ptr: iteration variable, struct uci_element *
 557  *
 558  * use like a for loop, e.g:
 559  *   uci_foreach(&list, p) {
 560  *      ...
 561  *   }
 562  */
 563 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 564         for(_ptr = list_to_element((_list)->next),              \
 565                 _tmp = list_to_element(_ptr->list.next);        \
 566                 &_ptr->list != (_list);                 \
 567                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 568
 569 /**
 570  * uci_list_empty: returns true if a list is empty
 571  * @list: list head
 572  */
 573 #define uci_list_empty(list) ((list)->next == (list))
 574
 575 /* wrappers for dynamic type handling */
 576 #define uci_type_backend UCI_TYPE_BACKEND
 577 #define uci_type_delta UCI_TYPE_DELTA
 578 #define uci_type_package UCI_TYPE_PACKAGE
 579 #define uci_type_section UCI_TYPE_SECTION
 580 #define uci_type_option UCI_TYPE_OPTION
 581
 582 /* element typecasting */
 583 #ifdef UCI_DEBUG_TYPECAST
 584 static const char *uci_typestr[] = {
 585         [uci_type_backend] = "backend",
 586         [uci_type_delta] = "delta",
 587         [uci_type_package] = "package",
 588         [uci_type_section] = "section",
 589         [uci_type_option] = "option",
 590 };
 591
 592 static void uci_typecast_error(int from, int to)
 593 {
 594         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 595 }
 596
 597 #define BUILD_CAST(_type) \
 598         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 599         { \
 600                 if (e->type != uci_type_ ## _type) { \
 601                         uci_typecast_error(e->type, uci_type_ ## _type); \
 602                 } \
 603                 return (struct uci_ ## _type *) e; \
 604         }
 605
 606 BUILD_CAST(backend)
 607 BUILD_CAST(delta)
 608 BUILD_CAST(package)
 609 BUILD_CAST(section)
 610 BUILD_CAST(option)
 611
 612 #else
 613 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 614 #define uci_to_delta(ptr) container_of(ptr, struct uci_delta, e)
 615 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 616 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 617 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 618 #endif
 619
 620 /**
 621  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 622  * @ctx: uci context
 623  * @type: {package,section,option}
 624  * @name: string containing the name of the element
 625  * @datasize: additional buffer size to reserve at the end of the struct
 626  */
 627 #define uci_alloc_element(ctx, type, name, datasize) \
 628         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 629
 630 #define uci_dataptr(ptr) \
 631         (((char *) ptr) + sizeof(*ptr))
 632
 633 /**
 634  * uci_lookup_package: look up a package
 635  * @ctx: uci context
 636  * @name: name of the package
 637  */
 638 static inline struct uci_package *
 639 uci_lookup_package(struct uci_context *ctx, const char *name)
 640 {
 641         struct uci_element *e = NULL;
 642         if (uci_lookup_next(ctx, &e, &ctx->root, name) == 0)
 643                 return uci_to_package(e);
 644         else
 645                 return NULL;
 646 }
 647
 648 /**
 649  * uci_lookup_section: look up a section
 650  * @ctx: uci context
 651  * @p: package that the section belongs to
 652  * @name: name of the section
 653  */
 654 static inline struct uci_section *
 655 uci_lookup_section(struct uci_context *ctx, struct uci_package *p, const char *name)
 656 {
 657         struct uci_element *e = NULL;
 658         if (uci_lookup_next(ctx, &e, &p->sections, name) == 0)
 659                 return uci_to_section(e);
 660         else
 661                 return NULL;
 662 }
 663
 664 /**
 665  * uci_lookup_option: look up an option
 666  * @ctx: uci context
 667  * @section: section that the option belongs to
 668  * @name: name of the option
 669  */
 670 static inline struct uci_option *
 671 uci_lookup_option(struct uci_context *ctx, struct uci_section *s, const char *name)
 672 {
 673         struct uci_element *e = NULL;
 674         if (uci_lookup_next(ctx, &e, &s->options, name) == 0)
 675                 return uci_to_option(e);
 676         else
 677                 return NULL;
 678 }
 679
 680 static inline const char *
 681 uci_lookup_option_string(struct uci_context *ctx, struct uci_section *s, const char *name)
 682 {
 683         struct uci_option *o;
 684
 685         o = uci_lookup_option(ctx, s, name);
 686         if (!o || o->type != UCI_TYPE_STRING)
 687                 return NULL;
 688
 689         return o->v.string;
 690 }
 691
 692 #ifndef BITS_PER_LONG
 693 #define BITS_PER_LONG (8 * sizeof(unsigned long))
 694 #endif
 695
 696 static inline void uci_bitfield_set(unsigned long *bits, int bit)
 697 {
 698         bits[bit / BITS_PER_LONG] |= (1UL << (bit % BITS_PER_LONG));
 699 }
 700
 701 #ifdef __cplusplus
 702 }
 703 #endif
 704
 705 #endif