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
  39 enum
  40 {
  41         UCI_OK = 0,
  42         UCI_ERR_MEM,
  43         UCI_ERR_INVAL,
  44         UCI_ERR_NOTFOUND,
  45         UCI_ERR_IO,
  46         UCI_ERR_PARSE,
  47         UCI_ERR_DUPLICATE,
  48         UCI_ERR_UNKNOWN,
  49         UCI_ERR_LAST
  50 };
  51
  52 struct uci_list;
  53 struct uci_list
  54 {
  55         struct uci_list *next;
  56         struct uci_list *prev;
  57 };
  58
  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_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  */
 108 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
 109
 110 /**
 111  * uci_export: Export one or all uci config packages
 112  * @ctx: uci context
 113  * @stream: output stream
 114  * @package: (optional) uci config package to export
 115  * @header: include the package header
 116  */
 117 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
 118
 119 /**
 120  * uci_load: Parse an uci config file and store it in the uci context
 121  *
 122  * @ctx: uci context
 123  * @name: name of the config file (relative to the config directory)
 124  * @package: store the loaded config package in this variable
 125  */
 126 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
 127
 128 /**
 129  * uci_unload: Unload a config file from the uci context
 130  *
 131  * @ctx: uci context
 132  * @package: pointer to the uci_package struct
 133  */
 134 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
 135
 136 /**
 137  * uci_cleanup: Clean up after an error
 138  *
 139  * @ctx: uci context
 140  */
 141 extern int uci_cleanup(struct uci_context *ctx);
 142
 143 /**
 144  * uci_lookup: Look up an uci element
 145  *
 146  * @ctx: uci context
 147  * @res: where to store the result
 148  * @package: uci_package struct
 149  * @section: config section (optional)
 150  * @option: option to search for (optional)
 151  *
 152  * If section is omitted, then a pointer to the config package is returned
 153  * If option is omitted, then a pointer to the config section is returned
 154  */
 155 extern int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *package, char *section, char *option);
 156
 157 /**
 158  * uci_set_element_value: Replace an element's value with a new one
 159  * @ctx: uci context
 160  * @element: pointer to an uci_element struct pointer
 161  * @value: new value
 162  *
 163  * Only valid for uci_option and uci_section. Will replace the type string
 164  * when used with an uci_section
 165  */
 166 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value);
 167
 168 /**
 169  * uci_set: Set an element's value; create the element if necessary
 170  * @ctx: uci context
 171  * @package: package name
 172  * @section: section name
 173  * @option: option name
 174  * @value: value (option) or type (section)
 175  */
 176 extern int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value);
 177
 178 /**
 179  * uci_del_element: Delete a section or option
 180  * @ctx: uci context
 181  * @e: element (section or option)
 182  */
 183 extern int uci_del_element(struct uci_context *ctx, struct uci_element *e);
 184
 185 /**
 186  * uci_del: Delete a section or option
 187  * @ctx: uci context
 188  * @p: uci package
 189  * @section: section name
 190  * @option: option name (optional)
 191  */
 192 extern int uci_del(struct uci_context *ctx, struct uci_package *p, char *section, char *option);
 193
 194 /**
 195  * uci_save: save change history for a package
 196  * @ctx: uci context
 197  * @p: uci_package struct
 198  */
 199 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 200
 201 /**
 202  * uci_commit: commit changes to a package
 203  * @ctx: uci context
 204  * @p: uci_package struct
 205  */
 206 extern int uci_commit(struct uci_context *ctx, struct uci_package *p);
 207
 208 /**
 209  * uci_list_configs: List available uci config files
 210  *
 211  * @ctx: uci context
 212  */
 213 extern char **uci_list_configs(struct uci_context *ctx);
 214
 215 /* UCI data structures */
 216 enum uci_type {
 217         UCI_TYPE_HISTORY = 0,
 218         UCI_TYPE_PACKAGE = 1,
 219         UCI_TYPE_SECTION = 2,
 220         UCI_TYPE_OPTION = 3
 221 };
 222
 223 enum uci_flags {
 224         UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
 225         UCI_FLAG_PERROR = (1 << 1), /* print error messages to stderr */
 226 };
 227
 228 struct uci_element
 229 {
 230         struct uci_list list;
 231         enum uci_type type;
 232         char *name;
 233 };
 234
 235 struct uci_context
 236 {
 237         /* list of config packages */
 238         struct uci_list root;
 239
 240         /* parser context, use for error handling only */
 241         struct uci_parse_context *pctx;
 242
 243         /* uci runtime flags */
 244         enum uci_flags flags;
 245
 246         /* private: */
 247         int errno;
 248         const char *func;
 249         jmp_buf trap;
 250         bool internal;
 251         char *buf;
 252         int bufsz;
 253 };
 254
 255 struct uci_parse_context
 256 {
 257         /* error context */
 258         const char *reason;
 259         int line;
 260         int byte;
 261
 262         /* private: */
 263         struct uci_package *package;
 264         struct uci_section *section;
 265         FILE *file;
 266         const char *name;
 267         char *buf;
 268         int bufsz;
 269 };
 270
 271 struct uci_package
 272 {
 273         struct uci_element e;
 274         struct uci_list sections;
 275         struct uci_context *ctx;
 276         bool confdir;
 277         char *path;
 278
 279         /* private: */
 280         int n_section;
 281         struct uci_list history;
 282 };
 283
 284 struct uci_section
 285 {
 286         struct uci_element e;
 287         struct uci_list options;
 288         struct uci_package *package;
 289         char *type;
 290 };
 291
 292 struct uci_option
 293 {
 294         struct uci_element e;
 295         struct uci_section *section;
 296         char *value;
 297 };
 298
 299 enum uci_command {
 300         UCI_CMD_ADD,
 301         UCI_CMD_REMOVE,
 302         UCI_CMD_CHANGE
 303 };
 304
 305 struct uci_history
 306 {
 307         struct uci_element e;
 308         enum uci_command cmd;
 309         char *section;
 310         char *value;
 311 };
 312
 313 /* linked list handling */
 314 #ifndef offsetof
 315 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 316 #endif
 317
 318 /**
 319  * container_of - cast a member of a structure out to the containing structure
 320  * @ptr:    the pointer to the member.
 321  * @type:   the type of the container struct this is embedded in.
 322  * @member: the name of the member within the struct.
 323  */
 324 #define container_of(ptr, type, member) \
 325         ((type *) ((char *)ptr - offsetof(type,member)))
 326
 327
 328 /**
 329  * uci_list_entry: casts an uci_list pointer to the containing struct.
 330  * @_type: config, section or option
 331  * @_ptr: pointer to the uci_list struct
 332  */
 333 #define element_to(type, ptr) \
 334         container_of(ptr, struct uci_ ## type, e)
 335
 336 #define list_to_element(ptr) \
 337         container_of(ptr, struct uci_element, list)
 338
 339 /**
 340  * uci_foreach_entry: loop through a list of uci elements
 341  * @_list: pointer to the uci_list struct
 342  * @_ptr: iteration variable, struct uci_element
 343  *
 344  * use like a for loop, e.g:
 345  *   uci_foreach(&list, p) {
 346  *      ...
 347  *   }
 348  */
 349 #define uci_foreach_element(_list, _ptr)                \
 350         for(_ptr = list_to_element((_list)->next);      \
 351                 &_ptr->list != (_list);                 \
 352                 _ptr = list_to_element(_ptr->list.next))
 353
 354 /**
 355  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 356  * @_list: pointer to the uci_list struct
 357  * @_tmp: temporary variable, struct uci_element *
 358  * @_ptr: iteration variable, struct uci_element *
 359  *
 360  * use like a for loop, e.g:
 361  *   uci_foreach(&list, p) {
 362  *      ...
 363  *   }
 364  */
 365 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 366         for(_ptr = list_to_element((_list)->next),              \
 367                 _tmp = list_to_element(_ptr->list.next);        \
 368                 &_ptr->list != (_list);                 \
 369                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 370
 371 /**
 372  * uci_list_empty: returns true if a list is empty
 373  * @list: list head
 374  */
 375 #define uci_list_empty(list) ((list)->next == (list))
 376
 377 /* wrappers for dynamic type handling */
 378 #define uci_type_history UCI_TYPE_HISTORY
 379 #define uci_type_package UCI_TYPE_PACKAGE
 380 #define uci_type_section UCI_TYPE_SECTION
 381 #define uci_type_option UCI_TYPE_OPTION
 382
 383 /* element typecasting */
 384 #ifdef UCI_DEBUG_TYPECAST
 385 static const char *uci_typestr[] = {
 386         [uci_type_history] = "history",
 387         [uci_type_package] = "package",
 388         [uci_type_section] = "section",
 389         [uci_type_option] = "option",
 390 };
 391
 392 static void uci_typecast_error(int from, int to)
 393 {
 394         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 395 }
 396
 397 #define BUILD_CAST(_type) \
 398         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 399         { \
 400                 if (e->type != uci_type_ ## _type) { \
 401                         uci_typecast_error(e->type, uci_type_ ## _type); \
 402                 } \
 403                 return (struct uci_ ## _type *) e; \
 404         }
 405
 406 BUILD_CAST(history)
 407 BUILD_CAST(package)
 408 BUILD_CAST(section)
 409 BUILD_CAST(option)
 410
 411 #else
 412 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 413 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 414 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 415 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 416 #endif
 417
 418 /**
 419  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 420  * @ctx: uci context
 421  * @type: {package,section,option}
 422  * @name: string containing the name of the element
 423  * @datasize: additional buffer size to reserve at the end of the struct
 424  */
 425 #define uci_alloc_element(ctx, type, name, datasize) \
 426         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 427
 428 #define uci_dataptr(ptr) \
 429         (((char *) ptr) + sizeof(*ptr))
 430
 431 #endif