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_ptr;
  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_backend;
  66 struct uci_parse_context;
  67
  68
  69 /**
  70  * uci_alloc_context: Allocate a new uci context
  71  */
  72 extern struct uci_context *uci_alloc_context(void);
  73
  74 /**
  75  * uci_free_context: Free the uci context including all of its data
  76  */
  77 extern void uci_free_context(struct uci_context *ctx);
  78
  79 /**
  80  * uci_perror: Print the last uci error that occured
  81  * @ctx: uci context
  82  * @str: string to print before the error message
  83  */
  84 extern void uci_perror(struct uci_context *ctx, const char *str);
  85
  86 /**
  87  * uci_import: Import uci config data from a stream
  88  * @ctx: uci context
  89  * @stream: file stream to import from
  90  * @name: (optional) assume the config has the given name
  91  * @package: (optional) store the last parsed config package in this variable
  92  * @single: ignore the 'package' keyword and parse everything into a single package
  93  *
  94  * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
  95  * if 'package' points to a non-null struct pointer, enable history tracking and merge
  96  */
  97 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
  98
  99 /**
 100  * uci_export: Export one or all uci config packages
 101  * @ctx: uci context
 102  * @stream: output stream
 103  * @package: (optional) uci config package to export
 104  * @header: include the package header
 105  */
 106 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
 107
 108 /**
 109  * uci_load: Parse an uci config file and store it in the uci context
 110  *
 111  * @ctx: uci context
 112  * @name: name of the config file (relative to the config directory)
 113  * @package: store the loaded config package in this variable
 114  */
 115 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
 116
 117 /**
 118  * uci_unload: Unload a config file from the uci context
 119  *
 120  * @ctx: uci context
 121  * @package: pointer to the uci_package struct
 122  */
 123 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
 124
 125 /**
 126  * uci_lookup_ptr: Split an uci tuple string and look up an element tree
 127  * @ctx: uci context
 128  * @ptr: lookup result struct
 129  * @str: uci tuple string to look up
 130  * @extended: allow extended syntax lookup
 131  *
 132  * if extended is set to true, uci_lookup_ptr supports the following
 133  * extended syntax:
 134  *
 135  * Examples:
 136  *   network.@interface[0].ifname ('ifname' option of the first interface section)
 137  *   network.@interface[-1]       (last interface section)
 138  * Note: uci_lookup_ext will automatically load a config package if necessary
 139  */
 140 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
 141
 142 /**
 143  * uci_add_section: Add an unnamed section
 144  * @ctx: uci context
 145  * @p: package to add the section to
 146  * @type: section type
 147  * @res: pointer to store a reference to the new section in
 148  */
 149 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
 150
 151 /**
 152  * uci_set_element_value: Replace an element's value with a new one
 153  * @ctx: uci context
 154  * @element: pointer to an uci_element struct pointer
 155  * @value: new value
 156  *
 157  * Only valid for uci_option and uci_section. Will replace the type string
 158  * when used with an uci_section
 159  */
 160 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, const char *value);
 161
 162 /**
 163  * uci_set: Set an element's value; create the element if necessary
 164  * @ctx: uci context
 165  * @package: package name
 166  * @section: section name
 167  * @option: option name
 168  * @value: value (option) or type (section)
 169  * @result: store the updated element in this variable (optional)
 170  */
 171 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);
 172
 173 /**
 174  * uci_add_list: Append a string to an element list
 175  * @ctx: uci context
 176  * @ptr: uci pointer (with value)
 177  *
 178  * Note: if the given option already contains a string value,
 179  * it will be converted to an 1-element-list before appending the next element
 180  */
 181 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
 182
 183 /**
 184  * uci_rename: Rename an element
 185  * @ctx: uci context
 186  * @ptr: uci pointer (with value)
 187  */
 188 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
 189
 190 /**
 191  * uci_delete: Delete a section or option
 192  * @ctx: uci context
 193  * @ptr: uci pointer
 194  */
 195 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
 196
 197 /**
 198  * uci_save: save change history for a package
 199  * @ctx: uci context
 200  * @p: uci_package struct
 201  */
 202 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 203
 204 /**
 205  * uci_commit: commit changes to a package
 206  * @ctx: uci context
 207  * @p: uci_package struct pointer
 208  * @overwrite: overwrite existing config data and flush history
 209  *
 210  * committing may reload the whole uci_package data,
 211  * the supplied pointer is updated accordingly
 212  */
 213 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 214
 215 /**
 216  * uci_list_configs: List available uci config files
 217  * @ctx: uci context
 218  *
 219  * caller is responsible for freeing the allocated memory behind list
 220  */
 221 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 222
 223 /**
 224  * uci_set_savedir: override the default history save directory
 225  * @ctx: uci context
 226  * @dir: directory name
 227  */
 228 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 229
 230 /**
 231  * uci_set_savedir: override the default config storage directory
 232  * @ctx: uci context
 233  * @dir: directory name
 234  */
 235 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 236
 237 /**
 238  * uci_add_history_path: add a directory to the search path for change history files
 239  * @ctx: uci context
 240  * @dir: directory name
 241  *
 242  * This function allows you to add directories, which contain 'overlays'
 243  * for the active config, that will never be committed.
 244  */
 245 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 246
 247 /**
 248  * uci_revert: revert all changes to a config item
 249  * @ctx: uci context
 250  * @ptr: uci pointer
 251  */
 252 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 253
 254 /**
 255  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 256  * @ctx: uci context
 257  * @stream: input stream
 258  * @str: pointer to the current line (use NULL for parsing the next line)
 259  * @result: pointer for the result
 260  */
 261 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 262
 263 /**
 264  * uci_set_backend: change the default backend
 265  * @ctx: uci context
 266  * @name: name of the backend
 267  *
 268  * The default backend is "file", which uses /etc/config for config storage
 269  */
 270 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 271
 272 /**
 273  * uci_validate_text: validate a value string for uci options
 274  * @str: value
 275  *
 276  * this function checks whether a given string is acceptable as value
 277  * for uci options
 278  */
 279 extern bool uci_validate_text(const char *str);
 280
 281 /* UCI data structures */
 282 enum uci_type {
 283         UCI_TYPE_UNSPEC = 0,
 284         UCI_TYPE_HISTORY = 1,
 285         UCI_TYPE_PACKAGE = 2,
 286         UCI_TYPE_SECTION = 3,
 287         UCI_TYPE_OPTION = 4,
 288         UCI_TYPE_PATH = 5,
 289         UCI_TYPE_BACKEND = 6,
 290         UCI_TYPE_ITEM = 7,
 291 };
 292
 293 enum uci_option_type {
 294         UCI_TYPE_STRING = 0,
 295         UCI_TYPE_LIST = 1,
 296 };
 297
 298 enum uci_flags {
 299         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 300         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 301         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 302         UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
 303 };
 304
 305 struct uci_element
 306 {
 307         struct uci_list list;
 308         enum uci_type type;
 309         char *name;
 310 };
 311
 312 struct uci_backend
 313 {
 314         struct uci_element e;
 315         char **(*list_configs)(struct uci_context *ctx);
 316         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 317         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 318
 319         /* private: */
 320         const void *ptr;
 321         void *priv;
 322 };
 323
 324 struct uci_context
 325 {
 326         /* list of config packages */
 327         struct uci_list root;
 328
 329         /* parser context, use for error handling only */
 330         struct uci_parse_context *pctx;
 331
 332         /* backend for import and export */
 333         struct uci_backend *backend;
 334         struct uci_list backends;
 335
 336         /* uci runtime flags */
 337         enum uci_flags flags;
 338
 339         char *confdir;
 340         char *savedir;
 341
 342         /* search path for history files */
 343         struct uci_list history_path;
 344
 345         /* private: */
 346         int err;
 347         const char *func;
 348         jmp_buf trap;
 349         bool internal, nested;
 350         char *buf;
 351         int bufsz;
 352 };
 353
 354 struct uci_package
 355 {
 356         struct uci_element e;
 357         struct uci_list sections;
 358         struct uci_context *ctx;
 359         bool has_history;
 360         char *path;
 361
 362         /* private: */
 363         struct uci_backend *backend;
 364         void *priv;
 365         int n_section;
 366         struct uci_list history;
 367         struct uci_list saved_history;
 368 };
 369
 370 struct uci_section
 371 {
 372         struct uci_element e;
 373         struct uci_list options;
 374         struct uci_package *package;
 375         bool anonymous;
 376         char *type;
 377 };
 378
 379 struct uci_option
 380 {
 381         struct uci_element e;
 382         struct uci_section *section;
 383         enum uci_option_type type;
 384         union {
 385                 struct uci_list list;
 386                 char *string;
 387         } v;
 388 };
 389
 390 enum uci_command {
 391         UCI_CMD_ADD,
 392         UCI_CMD_REMOVE,
 393         UCI_CMD_CHANGE,
 394         UCI_CMD_RENAME,
 395         UCI_CMD_LIST_ADD,
 396 };
 397
 398 struct uci_history
 399 {
 400         struct uci_element e;
 401         enum uci_command cmd;
 402         char *section;
 403         char *value;
 404 };
 405
 406 struct uci_ptr
 407 {
 408         enum uci_type target;
 409         enum {
 410                 UCI_LOOKUP_DONE =     (1 << 0),
 411                 UCI_LOOKUP_COMPLETE = (1 << 1),
 412                 UCI_LOOKUP_EXTENDED = (1 << 2),
 413         } flags;
 414
 415         struct uci_package *p;
 416         struct uci_section *s;
 417         struct uci_option *o;
 418         struct uci_element *last;
 419
 420         const char *package;
 421         const char *section;
 422         const char *option;
 423         const char *value;
 424 };
 425
 426
 427 /* linked list handling */
 428 #ifndef offsetof
 429 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 430 #endif
 431
 432 /**
 433  * container_of - cast a member of a structure out to the containing structure
 434  * @ptr:    the pointer to the member.
 435  * @type:   the type of the container struct this is embedded in.
 436  * @member: the name of the member within the struct.
 437  */
 438 #define container_of(ptr, type, member) \
 439         ((type *) ((char *)ptr - offsetof(type,member)))
 440
 441
 442 /**
 443  * uci_list_entry: casts an uci_list pointer to the containing struct.
 444  * @_type: config, section or option
 445  * @_ptr: pointer to the uci_list struct
 446  */
 447 #define list_to_element(ptr) \
 448         container_of(ptr, struct uci_element, list)
 449
 450 /**
 451  * uci_foreach_entry: loop through a list of uci elements
 452  * @_list: pointer to the uci_list struct
 453  * @_ptr: iteration variable, struct uci_element
 454  *
 455  * use like a for loop, e.g:
 456  *   uci_foreach(&list, p) {
 457  *      ...
 458  *   }
 459  */
 460 #define uci_foreach_element(_list, _ptr)                \
 461         for(_ptr = list_to_element((_list)->next);      \
 462                 &_ptr->list != (_list);                 \
 463                 _ptr = list_to_element(_ptr->list.next))
 464
 465 /**
 466  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 467  * @_list: pointer to the uci_list struct
 468  * @_tmp: temporary variable, struct uci_element *
 469  * @_ptr: iteration variable, struct uci_element *
 470  *
 471  * use like a for loop, e.g:
 472  *   uci_foreach(&list, p) {
 473  *      ...
 474  *   }
 475  */
 476 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 477         for(_ptr = list_to_element((_list)->next),              \
 478                 _tmp = list_to_element(_ptr->list.next);        \
 479                 &_ptr->list != (_list);                 \
 480                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 481
 482 /**
 483  * uci_list_empty: returns true if a list is empty
 484  * @list: list head
 485  */
 486 #define uci_list_empty(list) ((list)->next == (list))
 487
 488 /* wrappers for dynamic type handling */
 489 #define uci_type_backend UCI_TYPE_BACKEND
 490 #define uci_type_history UCI_TYPE_HISTORY
 491 #define uci_type_package UCI_TYPE_PACKAGE
 492 #define uci_type_section UCI_TYPE_SECTION
 493 #define uci_type_option UCI_TYPE_OPTION
 494
 495 /* element typecasting */
 496 #ifdef UCI_DEBUG_TYPECAST
 497 static const char *uci_typestr[] = {
 498         [uci_type_backend] = "backend",
 499         [uci_type_history] = "history",
 500         [uci_type_package] = "package",
 501         [uci_type_section] = "section",
 502         [uci_type_option] = "option",
 503 };
 504
 505 static void uci_typecast_error(int from, int to)
 506 {
 507         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 508 }
 509
 510 #define BUILD_CAST(_type) \
 511         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 512         { \
 513                 if (e->type != uci_type_ ## _type) { \
 514                         uci_typecast_error(e->type, uci_type_ ## _type); \
 515                 } \
 516                 return (struct uci_ ## _type *) e; \
 517         }
 518
 519 BUILD_CAST(backend)
 520 BUILD_CAST(history)
 521 BUILD_CAST(package)
 522 BUILD_CAST(section)
 523 BUILD_CAST(option)
 524
 525 #else
 526 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 527 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 528 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 529 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 530 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 531 #endif
 532
 533 /**
 534  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 535  * @ctx: uci context
 536  * @type: {package,section,option}
 537  * @name: string containing the name of the element
 538  * @datasize: additional buffer size to reserve at the end of the struct
 539  */
 540 #define uci_alloc_element(ctx, type, name, datasize) \
 541         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 542
 543 #define uci_dataptr(ptr) \
 544         (((char *) ptr) + sizeof(*ptr))
 545
 546 #endif