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_set: Set an element's value; create the element if necessary
 191  * @ctx: uci context
 192  * @package: package name
 193  * @section: section name
 194  * @option: option name
 195  * @value: value (option) or type (section)
 196  * @result: store the updated element in this variable (optional)
 197  */
 198 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);
 199
 200 /**
 201  * uci_rename: Rename an element
 202  * @ctx: uci context
 203  * @package: package name
 204  * @section: section name
 205  * @option: option name
 206  * @name: new name
 207  */
 208 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
 209
 210 /**
 211  * uci_delete_element: Delete a section or option
 212  * @ctx: uci context
 213  * @e: element (section or option)
 214  */
 215 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
 216
 217 /**
 218  * uci_delete: Delete a section or option
 219  * @ctx: uci context
 220  * @p: uci package
 221  * @section: section name
 222  * @option: option name (optional)
 223  */
 224 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option);
 225
 226 /**
 227  * uci_save: save change history 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 history
 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 history save directory
 254  * @ctx: uci context
 255  * @dir: directory name
 256  */
 257 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 258
 259 /**
 260  * uci_set_savedir: override the default config storage directory
 261  * @ctx: uci context
 262  * @dir: directory name
 263  */
 264 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 265
 266 /**
 267  * uci_add_history_path: add a directory to the search path for change history files
 268  * @ctx: uci context
 269  * @dir: directory name
 270  *
 271  * This function allows you to add directories, which contain 'overlays'
 272  * for the active config, that will never be committed.
 273  */
 274 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 275
 276 /**
 277  * uci_revert: revert all changes to a config item
 278  * @ctx: uci context
 279  * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
 280  * @section: section name (optional)
 281  * @option option name (optional)
 282  */
 283 extern int uci_revert(struct uci_context *ctx, struct uci_package **p, const char *section, const char *option);
 284
 285 /**
 286  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 287  * @ctx: uci context
 288  * @stream: input stream
 289  * @str: pointer to the current line (use NULL for parsing the next line)
 290  * @result: pointer for the result
 291  */
 292 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 293
 294 /**
 295  * uci_set_backend: change the default backend
 296  * @ctx: uci context
 297  * @name: name of the backend
 298  *
 299  * The default backend is "file", which uses /etc/config for config storage
 300  */
 301 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 302
 303 /**
 304  * uci_validate_text: validate a value string for uci options
 305  * @str: value
 306  *
 307  * this function checks whether a given string is acceptable as value
 308  * for uci options
 309  */
 310 extern bool uci_validate_text(const char *str);
 311
 312 /* UCI data structures */
 313 enum uci_type {
 314         UCI_TYPE_HISTORY = 0,
 315         UCI_TYPE_PACKAGE = 1,
 316         UCI_TYPE_SECTION = 2,
 317         UCI_TYPE_OPTION = 3,
 318         UCI_TYPE_PATH = 4,
 319         UCI_TYPE_BACKEND = 5,
 320 };
 321
 322 enum uci_option_type {
 323         UCI_TYPE_STRING = 0,
 324 };
 325
 326 enum uci_flags {
 327         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 328         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 329         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 330         UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
 331 };
 332
 333 struct uci_element
 334 {
 335         struct uci_list list;
 336         enum uci_type type;
 337         char *name;
 338 };
 339
 340 struct uci_backend
 341 {
 342         struct uci_element e;
 343         char **(*list_configs)(struct uci_context *ctx);
 344         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 345         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 346
 347         /* private: */
 348         const void *ptr;
 349         void *priv;
 350 };
 351
 352 struct uci_context
 353 {
 354         /* list of config packages */
 355         struct uci_list root;
 356
 357         /* parser context, use for error handling only */
 358         struct uci_parse_context *pctx;
 359
 360         /* backend for import and export */
 361         struct uci_backend *backend;
 362         struct uci_list backends;
 363
 364         /* uci runtime flags */
 365         enum uci_flags flags;
 366
 367         char *confdir;
 368         char *savedir;
 369
 370         /* search path for history files */
 371         struct uci_list history_path;
 372
 373         /* private: */
 374         int err;
 375         const char *func;
 376         jmp_buf trap;
 377         bool internal;
 378         char *buf;
 379         int bufsz;
 380 };
 381
 382 struct uci_package
 383 {
 384         struct uci_element e;
 385         struct uci_list sections;
 386         struct uci_context *ctx;
 387         bool has_history;
 388         char *path;
 389
 390         /* private: */
 391         struct uci_backend *backend;
 392         void *priv;
 393         int n_section;
 394         struct uci_list history;
 395         struct uci_list saved_history;
 396 };
 397
 398 struct uci_section
 399 {
 400         struct uci_element e;
 401         struct uci_list options;
 402         struct uci_package *package;
 403         bool anonymous;
 404         char *type;
 405 };
 406
 407 struct uci_option
 408 {
 409         struct uci_element e;
 410         struct uci_section *section;
 411         enum uci_option_type type;
 412         union {
 413                 struct uci_element *list;
 414                 char *string;
 415         } v;
 416 };
 417
 418 enum uci_command {
 419         UCI_CMD_ADD,
 420         UCI_CMD_REMOVE,
 421         UCI_CMD_CHANGE,
 422         UCI_CMD_RENAME
 423 };
 424
 425 struct uci_history
 426 {
 427         struct uci_element e;
 428         enum uci_command cmd;
 429         char *section;
 430         char *value;
 431 };
 432
 433
 434 /* linked list handling */
 435 #ifndef offsetof
 436 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 437 #endif
 438
 439 /**
 440  * container_of - cast a member of a structure out to the containing structure
 441  * @ptr:    the pointer to the member.
 442  * @type:   the type of the container struct this is embedded in.
 443  * @member: the name of the member within the struct.
 444  */
 445 #define container_of(ptr, type, member) \
 446         ((type *) ((char *)ptr - offsetof(type,member)))
 447
 448
 449 /**
 450  * uci_list_entry: casts an uci_list pointer to the containing struct.
 451  * @_type: config, section or option
 452  * @_ptr: pointer to the uci_list struct
 453  */
 454 #define list_to_element(ptr) \
 455         container_of(ptr, struct uci_element, list)
 456
 457 /**
 458  * uci_foreach_entry: loop through a list of uci elements
 459  * @_list: pointer to the uci_list struct
 460  * @_ptr: iteration variable, struct uci_element
 461  *
 462  * use like a for loop, e.g:
 463  *   uci_foreach(&list, p) {
 464  *      ...
 465  *   }
 466  */
 467 #define uci_foreach_element(_list, _ptr)                \
 468         for(_ptr = list_to_element((_list)->next);      \
 469                 &_ptr->list != (_list);                 \
 470                 _ptr = list_to_element(_ptr->list.next))
 471
 472 /**
 473  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 474  * @_list: pointer to the uci_list struct
 475  * @_tmp: temporary variable, struct uci_element *
 476  * @_ptr: iteration variable, struct uci_element *
 477  *
 478  * use like a for loop, e.g:
 479  *   uci_foreach(&list, p) {
 480  *      ...
 481  *   }
 482  */
 483 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 484         for(_ptr = list_to_element((_list)->next),              \
 485                 _tmp = list_to_element(_ptr->list.next);        \
 486                 &_ptr->list != (_list);                 \
 487                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 488
 489 /**
 490  * uci_list_empty: returns true if a list is empty
 491  * @list: list head
 492  */
 493 #define uci_list_empty(list) ((list)->next == (list))
 494
 495 /* wrappers for dynamic type handling */
 496 #define uci_type_backend UCI_TYPE_BACKEND
 497 #define uci_type_history UCI_TYPE_HISTORY
 498 #define uci_type_package UCI_TYPE_PACKAGE
 499 #define uci_type_section UCI_TYPE_SECTION
 500 #define uci_type_option UCI_TYPE_OPTION
 501
 502 /* element typecasting */
 503 #ifdef UCI_DEBUG_TYPECAST
 504 static const char *uci_typestr[] = {
 505         [uci_type_backend] = "backend",
 506         [uci_type_history] = "history",
 507         [uci_type_package] = "package",
 508         [uci_type_section] = "section",
 509         [uci_type_option] = "option",
 510 };
 511
 512 static void uci_typecast_error(int from, int to)
 513 {
 514         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 515 }
 516
 517 #define BUILD_CAST(_type) \
 518         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 519         { \
 520                 if (e->type != uci_type_ ## _type) { \
 521                         uci_typecast_error(e->type, uci_type_ ## _type); \
 522                 } \
 523                 return (struct uci_ ## _type *) e; \
 524         }
 525
 526 BUILD_CAST(backend)
 527 BUILD_CAST(history)
 528 BUILD_CAST(package)
 529 BUILD_CAST(section)
 530 BUILD_CAST(option)
 531
 532 #else
 533 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 534 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 535 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 536 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 537 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 538 #endif
 539
 540 /**
 541  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 542  * @ctx: uci context
 543  * @type: {package,section,option}
 544  * @name: string containing the name of the element
 545  * @datasize: additional buffer size to reserve at the end of the struct
 546  */
 547 #define uci_alloc_element(ctx, type, name, datasize) \
 548         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 549
 550 #define uci_dataptr(ptr) \
 551         (((char *) ptr) + sizeof(*ptr))
 552
 553 #endif