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_hook_ops;
  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 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
 160
 161 /**
 162  * uci_add_section: Add an unnamed section
 163  * @ctx: uci context
 164  * @p: package to add the section to
 165  * @type: section type
 166  * @res: pointer to store a reference to the new section in
 167  */
 168 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
 169
 170 /**
 171  * uci_set: Set an element's value; create the element if necessary
 172  * @ctx: uci context
 173  * @ptr: uci pointer
 174  *
 175  * The updated/created element is stored in ptr->last
 176  */
 177 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
 178
 179 /**
 180  * uci_add_list: Append a string to an element list
 181  * @ctx: uci context
 182  * @ptr: uci pointer (with value)
 183  *
 184  * Note: if the given option already contains a string value,
 185  * it will be converted to an 1-element-list before appending the next element
 186  */
 187 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
 188
 189 /**
 190  * uci_del_list: Remove a string from an element list
 191  * @ctx: uci context
 192  * @ptr: uci pointer (with value)
 193  *
 194  */
 195 extern int uci_del_list(struct uci_context *ctx, struct uci_ptr *ptr);
 196
 197 /**
 198  * uci_reorder: Reposition a section
 199  * @ctx: uci context
 200  * @s: uci section to reposition
 201  * @pos: new position in the section list
 202  */
 203 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
 204
 205 /**
 206  * uci_rename: Rename an element
 207  * @ctx: uci context
 208  * @ptr: uci pointer (with value)
 209  */
 210 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
 211
 212 /**
 213  * uci_delete: Delete a section or option
 214  * @ctx: uci context
 215  * @ptr: uci pointer
 216  */
 217 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
 218
 219 /**
 220  * uci_save: save change delta for a package
 221  * @ctx: uci context
 222  * @p: uci_package struct
 223  */
 224 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 225
 226 /**
 227  * uci_commit: commit changes to a package
 228  * @ctx: uci context
 229  * @p: uci_package struct pointer
 230  * @overwrite: overwrite existing config data and flush delta
 231  *
 232  * committing may reload the whole uci_package data,
 233  * the supplied pointer is updated accordingly
 234  */
 235 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 236
 237 /**
 238  * uci_list_configs: List available uci config files
 239  * @ctx: uci context
 240  *
 241  * caller is responsible for freeing the allocated memory behind list
 242  */
 243 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 244
 245 /**
 246  * uci_set_savedir: override the default delta save directory
 247  * @ctx: uci context
 248  * @dir: directory name
 249  */
 250 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 251
 252 /**
 253  * uci_set_savedir: override the default config storage directory
 254  * @ctx: uci context
 255  * @dir: directory name
 256  */
 257 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 258
 259 /**
 260  * uci_add_delta_path: add a directory to the search path for change delta files
 261  * @ctx: uci context
 262  * @dir: directory name
 263  *
 264  * This function allows you to add directories, which contain 'overlays'
 265  * for the active config, that will never be committed.
 266  */
 267 extern int uci_add_delta_path(struct uci_context *ctx, const char *dir);
 268
 269 /**
 270  * uci_revert: revert all changes to a config item
 271  * @ctx: uci context
 272  * @ptr: uci pointer
 273  */
 274 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 275
 276 /**
 277  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 278  * @ctx: uci context
 279  * @stream: input stream
 280  * @str: pointer to the current line (use NULL for parsing the next line)
 281  * @result: pointer for the result
 282  */
 283 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 284
 285 /**
 286  * uci_set_backend: change the default backend
 287  * @ctx: uci context
 288  * @name: name of the backend
 289  *
 290  * The default backend is "file", which uses /etc/config for config storage
 291  */
 292 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 293
 294 /**
 295  * uci_validate_text: validate a value string for uci options
 296  * @str: value
 297  *
 298  * this function checks whether a given string is acceptable as value
 299  * for uci options
 300  */
 301 extern bool uci_validate_text(const char *str);
 302
 303
 304 /**
 305  * uci_add_hook: add a uci hook
 306  * @ctx: uci context
 307  * @ops: uci hook ops
 308  *
 309  * NB: allocated and freed by the caller
 310  */
 311 extern int uci_add_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 312
 313 /**
 314  * uci_remove_hook: remove a uci hook
 315  * @ctx: uci context
 316  * @ops: uci hook ops
 317  */
 318 extern int uci_remove_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 319
 320 /**
 321  * uci_parse_ptr: parse a uci string into a uci_ptr
 322  * @ctx: uci context
 323  * @ptr: target data structure
 324  * @str: string to parse
 325  *
 326  * str is modified by this function
 327  */
 328 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str);
 329
 330 /**
 331  * uci_lookup_next: lookup a child element
 332  * @ctx: uci context
 333  * @e: target element pointer
 334  * @list: list of elements
 335  * @name: name of the child element
 336  *
 337  * if parent is NULL, the function looks up the package with the given name
 338  */
 339 int uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name);
 340
 341 /**
 342  * uci_parse_section: look up a set of options
 343  * @s: uci section
 344  * @opts: list of options to look up
 345  * @n_opts: number of options to look up
 346  * @tb: array of pointers to found options
 347  */
 348 void uci_parse_section(struct uci_section *s, const struct uci_parse_option *opts,
 349                        int n_opts, struct uci_option **tb);
 350
 351 /**
 352  * uci_hash_options: build a hash over a list of options
 353  * @tb: list of option pointers
 354  * @n_opts: number of options
 355  */
 356 uint32_t uci_hash_options(struct uci_option **tb, int n_opts);
 357
 358
 359 /* UCI data structures */
 360 enum uci_type {
 361         UCI_TYPE_UNSPEC = 0,
 362         UCI_TYPE_DELTA = 1,
 363         UCI_TYPE_PACKAGE = 2,
 364         UCI_TYPE_SECTION = 3,
 365         UCI_TYPE_OPTION = 4,
 366         UCI_TYPE_PATH = 5,
 367         UCI_TYPE_BACKEND = 6,
 368         UCI_TYPE_ITEM = 7,
 369         UCI_TYPE_HOOK = 8,
 370 };
 371
 372 enum uci_option_type {
 373         UCI_TYPE_STRING = 0,
 374         UCI_TYPE_LIST = 1,
 375 };
 376
 377 enum uci_flags {
 378         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 379         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 380         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 381         UCI_FLAG_SAVED_DELTA = (1 << 3), /* store the saved delta in memory as well */
 382 };
 383
 384 struct uci_element
 385 {
 386         struct uci_list list;
 387         enum uci_type type;
 388         char *name;
 389 };
 390
 391 struct uci_backend
 392 {
 393         struct uci_element e;
 394         char **(*list_configs)(struct uci_context *ctx);
 395         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 396         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 397
 398         /* private: */
 399         const void *ptr;
 400         void *priv;
 401 };
 402
 403 struct uci_context
 404 {
 405         /* list of config packages */
 406         struct uci_list root;
 407
 408         /* parser context, use for error handling only */
 409         struct uci_parse_context *pctx;
 410
 411         /* backend for import and export */
 412         struct uci_backend *backend;
 413         struct uci_list backends;
 414
 415         /* uci runtime flags */
 416         enum uci_flags flags;
 417
 418         char *confdir;
 419         char *savedir;
 420
 421         /* search path for delta files */
 422         struct uci_list delta_path;
 423
 424         /* private: */
 425         int err;
 426         const char *func;
 427         jmp_buf trap;
 428         bool internal, nested;
 429         char *buf;
 430         int bufsz;
 431
 432         struct uci_list hooks;
 433 };
 434
 435 struct uci_package
 436 {
 437         struct uci_element e;
 438         struct uci_list sections;
 439         struct uci_context *ctx;
 440         bool has_delta;
 441         char *path;
 442
 443         /* private: */
 444         struct uci_backend *backend;
 445         void *priv;
 446         int n_section;
 447         struct uci_list delta;
 448         struct uci_list saved_delta;
 449 };
 450
 451 struct uci_section
 452 {
 453         struct uci_element e;
 454         struct uci_list options;
 455         struct uci_package *package;
 456         bool anonymous;
 457         char *type;
 458 };
 459
 460 struct uci_option
 461 {
 462         struct uci_element e;
 463         struct uci_section *section;
 464         enum uci_option_type type;
 465         union {
 466                 struct uci_list list;
 467                 char *string;
 468         } v;
 469 };
 470
 471 enum uci_command {
 472         UCI_CMD_ADD,
 473         UCI_CMD_REMOVE,
 474         UCI_CMD_CHANGE,
 475         UCI_CMD_RENAME,
 476         UCI_CMD_REORDER,
 477         UCI_CMD_LIST_ADD,
 478         UCI_CMD_LIST_DEL,
 479 };
 480
 481 struct uci_delta
 482 {
 483         struct uci_element e;
 484         enum uci_command cmd;
 485         char *section;
 486         char *value;
 487 };
 488
 489 struct uci_ptr
 490 {
 491         enum uci_type target;
 492         enum {
 493                 UCI_LOOKUP_DONE =     (1 << 0),
 494                 UCI_LOOKUP_COMPLETE = (1 << 1),
 495                 UCI_LOOKUP_EXTENDED = (1 << 2),
 496         } flags;
 497
 498         struct uci_package *p;
 499         struct uci_section *s;
 500         struct uci_option *o;
 501         struct uci_element *last;
 502
 503         const char *package;
 504         const char *section;
 505         const char *option;
 506         const char *value;
 507 };
 508
 509 struct uci_hook_ops
 510 {
 511         void (*load)(const struct uci_hook_ops *ops, struct uci_package *p);
 512         void (*set)(const struct uci_hook_ops *ops, struct uci_package *p, struct uci_delta *e);
 513 };
 514
 515 struct uci_hook
 516 {
 517         struct uci_element e;
 518         const struct uci_hook_ops *ops;
 519 };
 520
 521 struct uci_parse_option {
 522         const char *name;
 523         enum uci_option_type type;
 524 };
 525
 526
 527 /* linked list handling */
 528 #ifndef offsetof
 529 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 530 #endif
 531
 532 /**
 533  * container_of - cast a member of a structure out to the containing structure
 534  * @ptr:    the pointer to the member.
 535  * @type:   the type of the container struct this is embedded in.
 536  * @member: the name of the member within the struct.
 537  */
 538 #ifndef container_of
 539 #define container_of(ptr, type, member) \
 540         ((type *) ((char *)ptr - offsetof(type,member)))
 541 #endif
 542
 543
 544 /**
 545  * uci_list_entry: casts an uci_list pointer to the containing struct.
 546  * @_type: config, section or option
 547  * @_ptr: pointer to the uci_list struct
 548  */
 549 #define list_to_element(ptr) \
 550         container_of(ptr, struct uci_element, list)
 551
 552 /**
 553  * uci_foreach_entry: loop through a list of uci elements
 554  * @_list: pointer to the uci_list struct
 555  * @_ptr: iteration variable, struct uci_element
 556  *
 557  * use like a for loop, e.g:
 558  *   uci_foreach(&list, p) {
 559  *      ...
 560  *   }
 561  */
 562 #define uci_foreach_element(_list, _ptr)                \
 563         for(_ptr = list_to_element((_list)->next);      \
 564                 &_ptr->list != (_list);                 \
 565                 _ptr = list_to_element(_ptr->list.next))
 566
 567 /**
 568  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 569  * @_list: pointer to the uci_list struct
 570  * @_tmp: temporary variable, struct uci_element *
 571  * @_ptr: iteration variable, struct uci_element *
 572  *
 573  * use like a for loop, e.g:
 574  *   uci_foreach(&list, p) {
 575  *      ...
 576  *   }
 577  */
 578 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 579         for(_ptr = list_to_element((_list)->next),              \
 580                 _tmp = list_to_element(_ptr->list.next);        \
 581                 &_ptr->list != (_list);                 \
 582                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 583
 584 /**
 585  * uci_list_empty: returns true if a list is empty
 586  * @list: list head
 587  */
 588 #define uci_list_empty(list) ((list)->next == (list))
 589
 590 /* wrappers for dynamic type handling */
 591 #define uci_type_backend UCI_TYPE_BACKEND
 592 #define uci_type_delta UCI_TYPE_DELTA
 593 #define uci_type_package UCI_TYPE_PACKAGE
 594 #define uci_type_section UCI_TYPE_SECTION
 595 #define uci_type_option UCI_TYPE_OPTION
 596 #define uci_type_hook UCI_TYPE_HOOK
 597
 598 /* element typecasting */
 599 #ifdef UCI_DEBUG_TYPECAST
 600 static const char *uci_typestr[] = {
 601         [uci_type_backend] = "backend",
 602         [uci_type_delta] = "delta",
 603         [uci_type_package] = "package",
 604         [uci_type_section] = "section",
 605         [uci_type_option] = "option",
 606         [uci_type_hook] = "hook",
 607 };
 608
 609 static void uci_typecast_error(int from, int to)
 610 {
 611         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 612 }
 613
 614 #define BUILD_CAST(_type) \
 615         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 616         { \
 617                 if (e->type != uci_type_ ## _type) { \
 618                         uci_typecast_error(e->type, uci_type_ ## _type); \
 619                 } \
 620                 return (struct uci_ ## _type *) e; \
 621         }
 622
 623 BUILD_CAST(backend)
 624 BUILD_CAST(delta)
 625 BUILD_CAST(package)
 626 BUILD_CAST(section)
 627 BUILD_CAST(option)
 628 BUILD_CAST(hook)
 629
 630 #else
 631 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 632 #define uci_to_delta(ptr) container_of(ptr, struct uci_delta, e)
 633 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 634 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 635 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 636 #define uci_to_hook(ptr)    container_of(ptr, struct uci_hook, e)
 637 #endif
 638
 639 /**
 640  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 641  * @ctx: uci context
 642  * @type: {package,section,option}
 643  * @name: string containing the name of the element
 644  * @datasize: additional buffer size to reserve at the end of the struct
 645  */
 646 #define uci_alloc_element(ctx, type, name, datasize) \
 647         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 648
 649 #define uci_dataptr(ptr) \
 650         (((char *) ptr) + sizeof(*ptr))
 651
 652 /**
 653  * uci_lookup_package: look up a package
 654  * @ctx: uci context
 655  * @name: name of the package
 656  */
 657 static inline struct uci_package *
 658 uci_lookup_package(struct uci_context *ctx, const char *name)
 659 {
 660         struct uci_element *e = NULL;
 661         if (uci_lookup_next(ctx, &e, &ctx->root, name) == 0)
 662                 return uci_to_package(e);
 663         else
 664                 return NULL;
 665 }
 666
 667 /**
 668  * uci_lookup_section: look up a section
 669  * @ctx: uci context
 670  * @p: package that the section belongs to
 671  * @name: name of the section
 672  */
 673 static inline struct uci_section *
 674 uci_lookup_section(struct uci_context *ctx, struct uci_package *p, const char *name)
 675 {
 676         struct uci_element *e = NULL;
 677         if (uci_lookup_next(ctx, &e, &p->sections, name) == 0)
 678                 return uci_to_section(e);
 679         else
 680                 return NULL;
 681 }
 682
 683 /**
 684  * uci_lookup_option: look up an option
 685  * @ctx: uci context
 686  * @section: section that the option belongs to
 687  * @name: name of the option
 688  */
 689 static inline struct uci_option *
 690 uci_lookup_option(struct uci_context *ctx, struct uci_section *s, const char *name)
 691 {
 692         struct uci_element *e = NULL;
 693         if (uci_lookup_next(ctx, &e, &s->options, name) == 0)
 694                 return uci_to_option(e);
 695         else
 696                 return NULL;
 697 }
 698
 699 static inline const char *
 700 uci_lookup_option_string(struct uci_context *ctx, struct uci_section *s, const char *name)
 701 {
 702         struct uci_option *o;
 703
 704         o = uci_lookup_option(ctx, s, name);
 705         if (!o || o->type != UCI_TYPE_STRING)
 706                 return NULL;
 707
 708         return o->v.string;
 709 }
 710
 711 #ifdef __cplusplus
 712 }
 713 #endif
 714
 715 #endif