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 General Public License for more details.
  13  */
  14
  15 #ifndef __LIBUCI_H
  16 #define __LIBUCI_H
  17
  18 #include "uci_config.h"
  19
  20 /*
  21  * you can use these defines to enable debugging behavior for
  22  * apps compiled against libuci:
  23  *
  24  * #define UCI_DEBUG_TYPECAST:
  25  *   enable uci_element typecast checking at run time
  26  *
  27  */
  28
  29 #include <stdbool.h>
  30 #include <setjmp.h>
  31 #include <stdio.h>
  32
  33 #define UCI_CONFDIR "/etc/config"
  34 #define UCI_SAVEDIR "/tmp/.uci"
  35 #define UCI_DIRMODE 0700
  36 #define UCI_FILEMODE 0600
  37
  38 enum
  39 {
  40         UCI_OK = 0,
  41         UCI_ERR_MEM,
  42         UCI_ERR_INVAL,
  43         UCI_ERR_NOTFOUND,
  44         UCI_ERR_IO,
  45         UCI_ERR_PARSE,
  46         UCI_ERR_DUPLICATE,
  47         UCI_ERR_UNKNOWN,
  48         UCI_ERR_LAST
  49 };
  50
  51 struct uci_list;
  52 struct uci_list
  53 {
  54         struct uci_list *next;
  55         struct uci_list *prev;
  56 };
  57
  58 struct uci_ptr;
  59 struct uci_element;
  60 struct uci_package;
  61 struct uci_section;
  62 struct uci_option;
  63 struct uci_history;
  64 struct uci_context;
  65 struct uci_backend;
  66 struct uci_parse_context;
  67
  68
  69 /**
  70  * uci_alloc_context: Allocate a new uci context
  71  */
  72 extern struct uci_context *uci_alloc_context(void);
  73
  74 /**
  75  * uci_free_context: Free the uci context including all of its data
  76  */
  77 extern void uci_free_context(struct uci_context *ctx);
  78
  79 /**
  80  * uci_perror: Print the last uci error that occured
  81  * @ctx: uci context
  82  * @str: string to print before the error message
  83  */
  84 extern void uci_perror(struct uci_context *ctx, const char *str);
  85
  86 /**
  87  * uci_import: Import uci config data from a stream
  88  * @ctx: uci context
  89  * @stream: file stream to import from
  90  * @name: (optional) assume the config has the given name
  91  * @package: (optional) store the last parsed config package in this variable
  92  * @single: ignore the 'package' keyword and parse everything into a single package
  93  *
  94  * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
  95  * if 'package' points to a non-null struct pointer, enable history tracking and merge
  96  */
  97 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
  98
  99 /**
 100  * uci_export: Export one or all uci config packages
 101  * @ctx: uci context
 102  * @stream: output stream
 103  * @package: (optional) uci config package to export
 104  * @header: include the package header
 105  */
 106 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
 107
 108 /**
 109  * uci_load: Parse an uci config file and store it in the uci context
 110  *
 111  * @ctx: uci context
 112  * @name: name of the config file (relative to the config directory)
 113  * @package: store the loaded config package in this variable
 114  */
 115 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
 116
 117 /**
 118  * uci_unload: Unload a config file from the uci context
 119  *
 120  * @ctx: uci context
 121  * @package: pointer to the uci_package struct
 122  */
 123 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
 124
 125 /**
 126  * uci_lookup: Look up an uci element
 127  *
 128  * @ctx: uci context
 129  * @res: where to store the result
 130  * @package: uci_package struct
 131  * @section: config section (optional)
 132  * @option: option to search for (optional)
 133  *
 134  * If section is omitted, then a pointer to the config package is returned
 135  * If option is omitted, then a pointer to the config section is returned
 136  */
 137 extern int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *package, const char *section, const char *option);
 138
 139 /**
 140  * uci_lookup_ptr: Split an uci tuple string and look up elements
 141  * @ctx: uci context
 142  * @ptr: lookup result struct
 143  * @str: uci tuple string to look up
 144  * @extended: allow extended syntax lookup
 145  */
 146 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
 147
 148 /**
 149  * uci_lookup_ext: Extended lookup for an uci element
 150  *
 151  * @ctx: uci context
 152  * @res: where to store the result
 153  * @ptr: uci pointer tuple
 154  *
 155  * Looks up an element using the extended syntax.
 156  * It can look up sections by an index with an optional type.
 157  *
 158  * Examples:
 159  *   network.@interface[0].ifname ('ifname' option of the first interface section)
 160  *   network.@interface[-1]       (last interface section)
 161  * Note: uci_lookup_ext will automatically load a config package if necessary
 162  */
 163 extern int uci_lookup_ext(struct uci_context *ctx, struct uci_element **res, char *ptr);
 164
 165 /**
 166  * uci_add_section: Add an unnamed section
 167  * @ctx: uci context
 168  * @p: package to add the section to
 169  * @type: section type
 170  * @res: pointer to store a reference to the new section in
 171  */
 172 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
 173
 174 /**
 175  * uci_set_element_value: Replace an element's value with a new one
 176  * @ctx: uci context
 177  * @element: pointer to an uci_element struct pointer
 178  * @value: new value
 179  *
 180  * Only valid for uci_option and uci_section. Will replace the type string
 181  * when used with an uci_section
 182  */
 183 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, const char *value);
 184
 185 /**
 186  * uci_add_element_list: Append a string to a list option
 187  * @ctx: uci context
 188  * @option: pointer to the uci option element
 189  * @value: string to append
 190  */
 191 extern int uci_add_element_list(struct uci_context *ctx, struct uci_option *o, const char *value);
 192
 193 /**
 194  * uci_set: Set an element's value; create the element if necessary
 195  * @ctx: uci context
 196  * @package: package name
 197  * @section: section name
 198  * @option: option name
 199  * @value: value (option) or type (section)
 200  * @result: store the updated element in this variable (optional)
 201  */
 202 extern int uci_set(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option, const char *value, struct uci_element **result);
 203
 204 /**
 205  * uci_add_list: Append a string to an element list
 206  * @ctx: uci context
 207  * @package: package name
 208  * @section: section name
 209  * @option: option name
 210  * @value: string value
 211  * @result: store the updated element in this variable (optional)
 212  *
 213  * Note: if the given option already contains a string, convert it to an 1-element-list
 214  * before appending the next element
 215  */
 216 extern int uci_add_list(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option, const char *value, struct uci_option **result);
 217
 218 /**
 219  * uci_rename: Rename an element
 220  * @ctx: uci context
 221  * @package: package name
 222  * @section: section name
 223  * @option: option name
 224  * @name: new name
 225  */
 226 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
 227
 228 /**
 229  * uci_delete_element: Delete a section or option
 230  * @ctx: uci context
 231  * @e: element (section or option)
 232  */
 233 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
 234
 235 /**
 236  * uci_delete: Delete a section or option
 237  * @ctx: uci context
 238  * @p: uci package
 239  * @section: section name
 240  * @option: option name (optional)
 241  */
 242 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option);
 243
 244 /**
 245  * uci_save: save change history for a package
 246  * @ctx: uci context
 247  * @p: uci_package struct
 248  */
 249 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 250
 251 /**
 252  * uci_commit: commit changes to a package
 253  * @ctx: uci context
 254  * @p: uci_package struct pointer
 255  * @overwrite: overwrite existing config data and flush history
 256  *
 257  * committing may reload the whole uci_package data,
 258  * the supplied pointer is updated accordingly
 259  */
 260 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 261
 262 /**
 263  * uci_list_configs: List available uci config files
 264  * @ctx: uci context
 265  *
 266  * caller is responsible for freeing the allocated memory behind list
 267  */
 268 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 269
 270 /**
 271  * uci_set_savedir: override the default history save directory
 272  * @ctx: uci context
 273  * @dir: directory name
 274  */
 275 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 276
 277 /**
 278  * uci_set_savedir: override the default config storage directory
 279  * @ctx: uci context
 280  * @dir: directory name
 281  */
 282 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 283
 284 /**
 285  * uci_add_history_path: add a directory to the search path for change history files
 286  * @ctx: uci context
 287  * @dir: directory name
 288  *
 289  * This function allows you to add directories, which contain 'overlays'
 290  * for the active config, that will never be committed.
 291  */
 292 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 293
 294 /**
 295  * uci_revert: revert all changes to a config item
 296  * @ctx: uci context
 297  * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
 298  * @section: section name (optional)
 299  * @option option name (optional)
 300  */
 301 extern int uci_revert(struct uci_context *ctx, struct uci_package **p, const char *section, const char *option);
 302
 303 /**
 304  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 305  * @ctx: uci context
 306  * @stream: input stream
 307  * @str: pointer to the current line (use NULL for parsing the next line)
 308  * @result: pointer for the result
 309  */
 310 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 311
 312 /**
 313  * uci_set_backend: change the default backend
 314  * @ctx: uci context
 315  * @name: name of the backend
 316  *
 317  * The default backend is "file", which uses /etc/config for config storage
 318  */
 319 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 320
 321 /**
 322  * uci_validate_text: validate a value string for uci options
 323  * @str: value
 324  *
 325  * this function checks whether a given string is acceptable as value
 326  * for uci options
 327  */
 328 extern bool uci_validate_text(const char *str);
 329
 330 /* UCI data structures */
 331 enum uci_type {
 332         UCI_TYPE_UNSPEC = 0,
 333         UCI_TYPE_HISTORY = 1,
 334         UCI_TYPE_PACKAGE = 2,
 335         UCI_TYPE_SECTION = 3,
 336         UCI_TYPE_OPTION = 4,
 337         UCI_TYPE_PATH = 5,
 338         UCI_TYPE_BACKEND = 6,
 339         UCI_TYPE_ITEM = 7,
 340 };
 341
 342 enum uci_option_type {
 343         UCI_TYPE_STRING = 0,
 344         UCI_TYPE_LIST = 1,
 345 };
 346
 347 enum uci_flags {
 348         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 349         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 350         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 351         UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
 352 };
 353
 354 struct uci_element
 355 {
 356         struct uci_list list;
 357         enum uci_type type;
 358         char *name;
 359 };
 360
 361 struct uci_backend
 362 {
 363         struct uci_element e;
 364         char **(*list_configs)(struct uci_context *ctx);
 365         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 366         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 367
 368         /* private: */
 369         const void *ptr;
 370         void *priv;
 371 };
 372
 373 struct uci_context
 374 {
 375         /* list of config packages */
 376         struct uci_list root;
 377
 378         /* parser context, use for error handling only */
 379         struct uci_parse_context *pctx;
 380
 381         /* backend for import and export */
 382         struct uci_backend *backend;
 383         struct uci_list backends;
 384
 385         /* uci runtime flags */
 386         enum uci_flags flags;
 387
 388         char *confdir;
 389         char *savedir;
 390
 391         /* search path for history files */
 392         struct uci_list history_path;
 393
 394         /* private: */
 395         int err;
 396         const char *func;
 397         jmp_buf trap;
 398         bool internal;
 399         char *buf;
 400         int bufsz;
 401 };
 402
 403 struct uci_package
 404 {
 405         struct uci_element e;
 406         struct uci_list sections;
 407         struct uci_context *ctx;
 408         bool has_history;
 409         char *path;
 410
 411         /* private: */
 412         struct uci_backend *backend;
 413         void *priv;
 414         int n_section;
 415         struct uci_list history;
 416         struct uci_list saved_history;
 417 };
 418
 419 struct uci_section
 420 {
 421         struct uci_element e;
 422         struct uci_list options;
 423         struct uci_package *package;
 424         bool anonymous;
 425         char *type;
 426 };
 427
 428 struct uci_option
 429 {
 430         struct uci_element e;
 431         struct uci_section *section;
 432         enum uci_option_type type;
 433         union {
 434                 struct uci_list list;
 435                 char *string;
 436         } v;
 437 };
 438
 439 enum uci_command {
 440         UCI_CMD_ADD,
 441         UCI_CMD_REMOVE,
 442         UCI_CMD_CHANGE,
 443         UCI_CMD_RENAME,
 444         UCI_CMD_LIST_ADD,
 445 };
 446
 447 struct uci_history
 448 {
 449         struct uci_element e;
 450         enum uci_command cmd;
 451         char *section;
 452         char *value;
 453 };
 454
 455 struct uci_ptr
 456 {
 457         enum uci_type target;
 458         enum {
 459                 UCI_LOOKUP_DONE =     (1 << 0),
 460                 UCI_LOOKUP_COMPLETE = (1 << 1),
 461                 UCI_LOOKUP_EXTENDED = (1 << 2),
 462         } flags;
 463
 464         struct uci_package *p;
 465         struct uci_section *s;
 466         struct uci_option *o;
 467
 468         char *package;
 469         char *section;
 470         char *option;
 471         char *value;
 472 };
 473
 474
 475 /* linked list handling */
 476 #ifndef offsetof
 477 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 478 #endif
 479
 480 /**
 481  * container_of - cast a member of a structure out to the containing structure
 482  * @ptr:    the pointer to the member.
 483  * @type:   the type of the container struct this is embedded in.
 484  * @member: the name of the member within the struct.
 485  */
 486 #define container_of(ptr, type, member) \
 487         ((type *) ((char *)ptr - offsetof(type,member)))
 488
 489
 490 /**
 491  * uci_list_entry: casts an uci_list pointer to the containing struct.
 492  * @_type: config, section or option
 493  * @_ptr: pointer to the uci_list struct
 494  */
 495 #define list_to_element(ptr) \
 496         container_of(ptr, struct uci_element, list)
 497
 498 /**
 499  * uci_foreach_entry: loop through a list of uci elements
 500  * @_list: pointer to the uci_list struct
 501  * @_ptr: iteration variable, struct uci_element
 502  *
 503  * use like a for loop, e.g:
 504  *   uci_foreach(&list, p) {
 505  *      ...
 506  *   }
 507  */
 508 #define uci_foreach_element(_list, _ptr)                \
 509         for(_ptr = list_to_element((_list)->next);      \
 510                 &_ptr->list != (_list);                 \
 511                 _ptr = list_to_element(_ptr->list.next))
 512
 513 /**
 514  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 515  * @_list: pointer to the uci_list struct
 516  * @_tmp: temporary variable, struct uci_element *
 517  * @_ptr: iteration variable, struct uci_element *
 518  *
 519  * use like a for loop, e.g:
 520  *   uci_foreach(&list, p) {
 521  *      ...
 522  *   }
 523  */
 524 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 525         for(_ptr = list_to_element((_list)->next),              \
 526                 _tmp = list_to_element(_ptr->list.next);        \
 527                 &_ptr->list != (_list);                 \
 528                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 529
 530 /**
 531  * uci_list_empty: returns true if a list is empty
 532  * @list: list head
 533  */
 534 #define uci_list_empty(list) ((list)->next == (list))
 535
 536 /* wrappers for dynamic type handling */
 537 #define uci_type_backend UCI_TYPE_BACKEND
 538 #define uci_type_history UCI_TYPE_HISTORY
 539 #define uci_type_package UCI_TYPE_PACKAGE
 540 #define uci_type_section UCI_TYPE_SECTION
 541 #define uci_type_option UCI_TYPE_OPTION
 542
 543 /* element typecasting */
 544 #ifdef UCI_DEBUG_TYPECAST
 545 static const char *uci_typestr[] = {
 546         [uci_type_backend] = "backend",
 547         [uci_type_history] = "history",
 548         [uci_type_package] = "package",
 549         [uci_type_section] = "section",
 550         [uci_type_option] = "option",
 551 };
 552
 553 static void uci_typecast_error(int from, int to)
 554 {
 555         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 556 }
 557
 558 #define BUILD_CAST(_type) \
 559         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 560         { \
 561                 if (e->type != uci_type_ ## _type) { \
 562                         uci_typecast_error(e->type, uci_type_ ## _type); \
 563                 } \
 564                 return (struct uci_ ## _type *) e; \
 565         }
 566
 567 BUILD_CAST(backend)
 568 BUILD_CAST(history)
 569 BUILD_CAST(package)
 570 BUILD_CAST(section)
 571 BUILD_CAST(option)
 572
 573 #else
 574 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 575 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 576 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 577 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 578 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 579 #endif
 580
 581 /**
 582  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 583  * @ctx: uci context
 584  * @type: {package,section,option}
 585  * @name: string containing the name of the element
 586  * @datasize: additional buffer size to reserve at the end of the struct
 587  */
 588 #define uci_alloc_element(ctx, type, name, datasize) \
 589         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 590
 591 #define uci_dataptr(ptr) \
 592         (((char *) ptr) + sizeof(*ptr))
 593
 594 #endif