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  */
 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_cleanup: Clean up after an error
 139  *
 140  * @ctx: uci context
 141  */
 142 extern int uci_cleanup(struct uci_context *ctx);
 143
 144 /**
 145  * uci_lookup: Look up an uci element
 146  *
 147  * @ctx: uci context
 148  * @res: where to store the result
 149  * @package: uci_package struct
 150  * @section: config section (optional)
 151  * @option: option to search for (optional)
 152  *
 153  * If section is omitted, then a pointer to the config package is returned
 154  * If option is omitted, then a pointer to the config section is returned
 155  */
 156 extern int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *package, char *section, char *option);
 157
 158 /**
 159  * uci_set_element_value: Replace an element's value with a new one
 160  * @ctx: uci context
 161  * @element: pointer to an uci_element struct pointer
 162  * @value: new value
 163  *
 164  * Only valid for uci_option and uci_section. Will replace the type string
 165  * when used with an uci_section
 166  */
 167 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value);
 168
 169 /**
 170  * uci_set: Set an element's value; create the element if necessary
 171  * @ctx: uci context
 172  * @package: package name
 173  * @section: section name
 174  * @option: option name
 175  * @value: value (option) or type (section)
 176  */
 177 extern int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value);
 178
 179 /**
 180  * uci_rename: Rename an element
 181  * @ctx: uci context
 182  * @package: package name
 183  * @section: section name
 184  * @option: option name
 185  * @name: new name
 186  */
 187 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
 188
 189 /**
 190  * uci_delete_element: Delete a section or option
 191  * @ctx: uci context
 192  * @e: element (section or option)
 193  */
 194 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
 195
 196 /**
 197  * uci_delete: Delete a section or option
 198  * @ctx: uci context
 199  * @p: uci package
 200  * @section: section name
 201  * @option: option name (optional)
 202  */
 203 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, char *section, char *option);
 204
 205 /**
 206  * uci_save: save change history for a package
 207  * @ctx: uci context
 208  * @p: uci_package struct
 209  */
 210 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 211
 212 /**
 213  * uci_commit: commit changes to a package
 214  * @ctx: uci context
 215  * @p: uci_package struct pointer
 216  *
 217  * committing may reload the whole uci_package data,
 218  * the supplied pointer is updated accordingly
 219  */
 220 extern int uci_commit(struct uci_context *ctx, struct uci_package **p);
 221
 222 /**
 223  * uci_list_configs: List available uci config files
 224  *
 225  * @ctx: uci context
 226  */
 227 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 228
 229 /* UCI data structures */
 230 enum uci_type {
 231         UCI_TYPE_HISTORY = 0,
 232         UCI_TYPE_PACKAGE = 1,
 233         UCI_TYPE_SECTION = 2,
 234         UCI_TYPE_OPTION = 3
 235 };
 236
 237 enum uci_flags {
 238         UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
 239         UCI_FLAG_PERROR = (1 << 1), /* print error messages to stderr */
 240 };
 241
 242 struct uci_element
 243 {
 244         struct uci_list list;
 245         enum uci_type type;
 246         char *name;
 247 };
 248
 249 struct uci_context
 250 {
 251         /* list of config packages */
 252         struct uci_list root;
 253
 254         /* parser context, use for error handling only */
 255         struct uci_parse_context *pctx;
 256
 257         /* uci runtime flags */
 258         enum uci_flags flags;
 259
 260         /* private: */
 261         int errno;
 262         const char *func;
 263         jmp_buf trap;
 264         bool internal;
 265         char *buf;
 266         int bufsz;
 267 };
 268
 269 struct uci_parse_context
 270 {
 271         /* error context */
 272         const char *reason;
 273         int line;
 274         int byte;
 275
 276         /* private: */
 277         struct uci_package *package;
 278         struct uci_section *section;
 279         FILE *file;
 280         const char *name;
 281         char *buf;
 282         int bufsz;
 283 };
 284
 285 struct uci_package
 286 {
 287         struct uci_element e;
 288         struct uci_list sections;
 289         struct uci_context *ctx;
 290         bool confdir;
 291         char *path;
 292
 293         /* private: */
 294         int n_section;
 295         struct uci_list history;
 296 };
 297
 298 struct uci_section
 299 {
 300         struct uci_element e;
 301         struct uci_list options;
 302         struct uci_package *package;
 303         bool anonymous;
 304         char *type;
 305 };
 306
 307 struct uci_option
 308 {
 309         struct uci_element e;
 310         struct uci_section *section;
 311         char *value;
 312 };
 313
 314 enum uci_command {
 315         UCI_CMD_ADD,
 316         UCI_CMD_REMOVE,
 317         UCI_CMD_CHANGE,
 318         UCI_CMD_RENAME
 319 };
 320
 321 struct uci_history
 322 {
 323         struct uci_element e;
 324         enum uci_command cmd;
 325         char *section;
 326         char *value;
 327 };
 328
 329 /* linked list handling */
 330 #ifndef offsetof
 331 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 332 #endif
 333
 334 /**
 335  * container_of - cast a member of a structure out to the containing structure
 336  * @ptr:    the pointer to the member.
 337  * @type:   the type of the container struct this is embedded in.
 338  * @member: the name of the member within the struct.
 339  */
 340 #define container_of(ptr, type, member) \
 341         ((type *) ((char *)ptr - offsetof(type,member)))
 342
 343
 344 /**
 345  * uci_list_entry: casts an uci_list pointer to the containing struct.
 346  * @_type: config, section or option
 347  * @_ptr: pointer to the uci_list struct
 348  */
 349 #define element_to(type, ptr) \
 350         container_of(ptr, struct uci_ ## type, e)
 351
 352 #define list_to_element(ptr) \
 353         container_of(ptr, struct uci_element, list)
 354
 355 /**
 356  * uci_foreach_entry: loop through a list of uci elements
 357  * @_list: pointer to the uci_list struct
 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(_list, _ptr)                \
 366         for(_ptr = list_to_element((_list)->next);      \
 367                 &_ptr->list != (_list);                 \
 368                 _ptr = list_to_element(_ptr->list.next))
 369
 370 /**
 371  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 372  * @_list: pointer to the uci_list struct
 373  * @_tmp: temporary variable, struct uci_element *
 374  * @_ptr: iteration variable, struct uci_element *
 375  *
 376  * use like a for loop, e.g:
 377  *   uci_foreach(&list, p) {
 378  *      ...
 379  *   }
 380  */
 381 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 382         for(_ptr = list_to_element((_list)->next),              \
 383                 _tmp = list_to_element(_ptr->list.next);        \
 384                 &_ptr->list != (_list);                 \
 385                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 386
 387 /**
 388  * uci_list_empty: returns true if a list is empty
 389  * @list: list head
 390  */
 391 #define uci_list_empty(list) ((list)->next == (list))
 392
 393 /* wrappers for dynamic type handling */
 394 #define uci_type_history UCI_TYPE_HISTORY
 395 #define uci_type_package UCI_TYPE_PACKAGE
 396 #define uci_type_section UCI_TYPE_SECTION
 397 #define uci_type_option UCI_TYPE_OPTION
 398
 399 /* element typecasting */
 400 #ifdef UCI_DEBUG_TYPECAST
 401 static const char *uci_typestr[] = {
 402         [uci_type_history] = "history",
 403         [uci_type_package] = "package",
 404         [uci_type_section] = "section",
 405         [uci_type_option] = "option",
 406 };
 407
 408 static void uci_typecast_error(int from, int to)
 409 {
 410         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 411 }
 412
 413 #define BUILD_CAST(_type) \
 414         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 415         { \
 416                 if (e->type != uci_type_ ## _type) { \
 417                         uci_typecast_error(e->type, uci_type_ ## _type); \
 418                 } \
 419                 return (struct uci_ ## _type *) e; \
 420         }
 421
 422 BUILD_CAST(history)
 423 BUILD_CAST(package)
 424 BUILD_CAST(section)
 425 BUILD_CAST(option)
 426
 427 #else
 428 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 429 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 430 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 431 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 432 #endif
 433
 434 /**
 435  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 436  * @ctx: uci context
 437  * @type: {package,section,option}
 438  * @name: string containing the name of the element
 439  * @datasize: additional buffer size to reserve at the end of the struct
 440  */
 441 #define uci_alloc_element(ctx, type, name, datasize) \
 442         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 443
 444 #define uci_dataptr(ptr) \
 445         (((char *) ptr) + sizeof(*ptr))
 446
 447 #endif