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