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