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_set_element_value: Replace an element's value with a new one
 161  * @ctx: uci context
 162  * @element: pointer to an uci_element struct pointer
 163  * @value: new value
 164  *
 165  * Only valid for uci_option and uci_section. Will replace the type string
 166  * when used with an uci_section
 167  */
 168 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value);
 169
 170 /**
 171  * uci_set: Set an element's value; create the element if necessary
 172  * @ctx: uci context
 173  * @package: package name
 174  * @section: section name
 175  * @option: option name
 176  * @value: value (option) or type (section)
 177  */
 178 extern int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value);
 179
 180 /**
 181  * uci_rename: Rename an element
 182  * @ctx: uci context
 183  * @package: package name
 184  * @section: section name
 185  * @option: option name
 186  * @name: new name
 187  */
 188 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
 189
 190 /**
 191  * uci_delete_element: Delete a section or option
 192  * @ctx: uci context
 193  * @e: element (section or option)
 194  */
 195 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
 196
 197 /**
 198  * uci_delete: Delete a section or option
 199  * @ctx: uci context
 200  * @p: uci package
 201  * @section: section name
 202  * @option: option name (optional)
 203  */
 204 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, char *section, char *option);
 205
 206 /**
 207  * uci_save: save change history for a package
 208  * @ctx: uci context
 209  * @p: uci_package struct
 210  */
 211 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 212
 213 /**
 214  * uci_commit: commit changes to a package
 215  * @ctx: uci context
 216  * @p: uci_package struct pointer
 217  * @overwrite: overwrite existing config data and flush history
 218  *
 219  * committing may reload the whole uci_package data,
 220  * the supplied pointer is updated accordingly
 221  */
 222 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 223
 224 /**
 225  * uci_list_configs: List available uci config files
 226  * @ctx: uci context
 227  */
 228 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 229
 230 /**
 231  * uci_set_savedir: override the default history save directory
 232  * @ctx: uci context
 233  * @dir: directory name
 234  */
 235 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 236
 237 /**
 238  * uci_set_savedir: override the default config storage directory
 239  * @ctx: uci context
 240  * @dir: directory name
 241  */
 242 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 243
 244 /**
 245  * uci_add_history_path: add a directory to the search path for change history files
 246  * @ctx: uci context
 247  * @dir: directory name
 248  */
 249 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 250
 251 /* UCI data structures */
 252 enum uci_type {
 253         UCI_TYPE_HISTORY = 0,
 254         UCI_TYPE_PACKAGE = 1,
 255         UCI_TYPE_SECTION = 2,
 256         UCI_TYPE_OPTION = 3,
 257         UCI_TYPE_PATH = 4
 258 };
 259
 260 enum uci_flags {
 261         UCI_FLAG_STRICT =      (1 << 0), /* strict mode for the parser */
 262         UCI_FLAG_PERROR =      (1 << 1), /* print parser error messages */
 263         UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
 264 };
 265
 266 struct uci_element
 267 {
 268         struct uci_list list;
 269         enum uci_type type;
 270         char *name;
 271 };
 272
 273 struct uci_context
 274 {
 275         /* list of config packages */
 276         struct uci_list root;
 277
 278         /* parser context, use for error handling only */
 279         struct uci_parse_context *pctx;
 280
 281         /* uci runtime flags */
 282         enum uci_flags flags;
 283
 284         char *confdir;
 285         char *savedir;
 286
 287         /* search path for history files */
 288         struct uci_list history_path;
 289
 290         /* private: */
 291         int errno;
 292         const char *func;
 293         jmp_buf trap;
 294         bool internal;
 295         char *buf;
 296         int bufsz;
 297 };
 298
 299 struct uci_parse_context
 300 {
 301         /* error context */
 302         const char *reason;
 303         int line;
 304         int byte;
 305
 306         /* private: */
 307         struct uci_package *package;
 308         struct uci_section *section;
 309         bool merge;
 310         FILE *file;
 311         const char *name;
 312         char *buf;
 313         int bufsz;
 314 };
 315
 316 struct uci_package
 317 {
 318         struct uci_element e;
 319         struct uci_list sections;
 320         struct uci_context *ctx;
 321         bool confdir;
 322         char *path;
 323
 324         /* private: */
 325         int n_section;
 326         struct uci_list history;
 327 };
 328
 329 struct uci_section
 330 {
 331         struct uci_element e;
 332         struct uci_list options;
 333         struct uci_package *package;
 334         bool anonymous;
 335         char *type;
 336 };
 337
 338 struct uci_option
 339 {
 340         struct uci_element e;
 341         struct uci_section *section;
 342         char *value;
 343 };
 344
 345 enum uci_command {
 346         UCI_CMD_ADD,
 347         UCI_CMD_REMOVE,
 348         UCI_CMD_CHANGE,
 349         UCI_CMD_RENAME
 350 };
 351
 352 struct uci_history
 353 {
 354         struct uci_element e;
 355         enum uci_command cmd;
 356         char *section;
 357         char *value;
 358 };
 359
 360 /* linked list handling */
 361 #ifndef offsetof
 362 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 363 #endif
 364
 365 /**
 366  * container_of - cast a member of a structure out to the containing structure
 367  * @ptr:    the pointer to the member.
 368  * @type:   the type of the container struct this is embedded in.
 369  * @member: the name of the member within the struct.
 370  */
 371 #define container_of(ptr, type, member) \
 372         ((type *) ((char *)ptr - offsetof(type,member)))
 373
 374
 375 /**
 376  * uci_list_entry: casts an uci_list pointer to the containing struct.
 377  * @_type: config, section or option
 378  * @_ptr: pointer to the uci_list struct
 379  */
 380 #define element_to(type, ptr) \
 381         container_of(ptr, struct uci_ ## type, e)
 382
 383 #define list_to_element(ptr) \
 384         container_of(ptr, struct uci_element, list)
 385
 386 /**
 387  * uci_foreach_entry: loop through a list of uci elements
 388  * @_list: pointer to the uci_list struct
 389  * @_ptr: iteration variable, struct uci_element
 390  *
 391  * use like a for loop, e.g:
 392  *   uci_foreach(&list, p) {
 393  *      ...
 394  *   }
 395  */
 396 #define uci_foreach_element(_list, _ptr)                \
 397         for(_ptr = list_to_element((_list)->next);      \
 398                 &_ptr->list != (_list);                 \
 399                 _ptr = list_to_element(_ptr->list.next))
 400
 401 /**
 402  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 403  * @_list: pointer to the uci_list struct
 404  * @_tmp: temporary variable, struct uci_element *
 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_safe(_list, _tmp, _ptr)             \
 413         for(_ptr = list_to_element((_list)->next),              \
 414                 _tmp = list_to_element(_ptr->list.next);        \
 415                 &_ptr->list != (_list);                 \
 416                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 417
 418 /**
 419  * uci_list_empty: returns true if a list is empty
 420  * @list: list head
 421  */
 422 #define uci_list_empty(list) ((list)->next == (list))
 423
 424 /* wrappers for dynamic type handling */
 425 #define uci_type_history UCI_TYPE_HISTORY
 426 #define uci_type_package UCI_TYPE_PACKAGE
 427 #define uci_type_section UCI_TYPE_SECTION
 428 #define uci_type_option UCI_TYPE_OPTION
 429
 430 /* element typecasting */
 431 #ifdef UCI_DEBUG_TYPECAST
 432 static const char *uci_typestr[] = {
 433         [uci_type_history] = "history",
 434         [uci_type_package] = "package",
 435         [uci_type_section] = "section",
 436         [uci_type_option] = "option",
 437 };
 438
 439 static void uci_typecast_error(int from, int to)
 440 {
 441         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 442 }
 443
 444 #define BUILD_CAST(_type) \
 445         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 446         { \
 447                 if (e->type != uci_type_ ## _type) { \
 448                         uci_typecast_error(e->type, uci_type_ ## _type); \
 449                 } \
 450                 return (struct uci_ ## _type *) e; \
 451         }
 452
 453 BUILD_CAST(history)
 454 BUILD_CAST(package)
 455 BUILD_CAST(section)
 456 BUILD_CAST(option)
 457
 458 #else
 459 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 460 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 461 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 462 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 463 #endif
 464
 465 /**
 466  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 467  * @ctx: uci context
 468  * @type: {package,section,option}
 469  * @name: string containing the name of the element
 470  * @datasize: additional buffer size to reserve at the end of the struct
 471  */
 472 #define uci_alloc_element(ctx, type, name, datasize) \
 473         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 474
 475 #define uci_dataptr(ptr) \
 476         (((char *) ptr) + sizeof(*ptr))
 477
 478 #endif