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_plugin;
  60 struct uci_hook_ops;
  61 struct uci_element;
  62 struct uci_package;
  63 struct uci_section;
  64 struct uci_option;
  65 struct uci_history;
  66 struct uci_context;
  67 struct uci_backend;
  68 struct uci_parse_context;
  69
  70
  71 /**
  72  * uci_alloc_context: Allocate a new uci context
  73  */
  74 extern struct uci_context *uci_alloc_context(void);
  75
  76 /**
  77  * uci_free_context: Free the uci context including all of its data
  78  */
  79 extern void uci_free_context(struct uci_context *ctx);
  80
  81 /**
  82  * uci_perror: Print the last uci error that occured
  83  * @ctx: uci context
  84  * @str: string to print before the error message
  85  */
  86 extern void uci_perror(struct uci_context *ctx, const char *str);
  87
  88 /**
  89  * uci_geterror: Get an error string for the last uci error
  90  * @ctx: uci context
  91  * @dest: target pointer for the string
  92  * @str: prefix for the error message
  93  *
  94  * Note: string must be freed by the caller
  95  */
  96 extern void uci_get_errorstr(struct uci_context *ctx, char **dest, 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  * if 'package' points to a non-null struct pointer, enable history tracking and merge
 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_lookup_ptr: Split an uci tuple string and look up an element tree
 139  * @ctx: uci context
 140  * @ptr: lookup result struct
 141  * @str: uci tuple string to look up
 142  * @extended: allow extended syntax lookup
 143  *
 144  * if extended is set to true, uci_lookup_ptr supports the following
 145  * extended syntax:
 146  *
 147  * Examples:
 148  *   network.@interface[0].ifname ('ifname' option of the first interface section)
 149  *   network.@interface[-1]       (last interface section)
 150  * Note: uci_lookup_ext will automatically load a config package if necessary
 151  */
 152 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
 153
 154 /**
 155  * uci_add_section: Add an unnamed section
 156  * @ctx: uci context
 157  * @p: package to add the section to
 158  * @type: section type
 159  * @res: pointer to store a reference to the new section in
 160  */
 161 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
 162
 163 /**
 164  * uci_set: Set an element's value; create the element if necessary
 165  * @ctx: uci context
 166  * @ptr: uci pointer
 167  *
 168  * The updated/created element is stored in ptr->last
 169  */
 170 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
 171
 172 /**
 173  * uci_add_list: Append a string to an element list
 174  * @ctx: uci context
 175  * @ptr: uci pointer (with value)
 176  *
 177  * Note: if the given option already contains a string value,
 178  * it will be converted to an 1-element-list before appending the next element
 179  */
 180 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
 181
 182 /**
 183  * uci_reorder: Reposition a section
 184  * @ctx: uci context
 185  * @s: uci section to reposition
 186  * @pos: new position in the section list
 187  */
 188 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
 189
 190 /**
 191  * uci_rename: Rename an element
 192  * @ctx: uci context
 193  * @ptr: uci pointer (with value)
 194  */
 195 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
 196
 197 /**
 198  * uci_delete: Delete a section or option
 199  * @ctx: uci context
 200  * @ptr: uci pointer
 201  */
 202 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
 203
 204 /**
 205  * uci_save: save change history for a package
 206  * @ctx: uci context
 207  * @p: uci_package struct
 208  */
 209 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 210
 211 /**
 212  * uci_commit: commit changes to a package
 213  * @ctx: uci context
 214  * @p: uci_package struct pointer
 215  * @overwrite: overwrite existing config data and flush history
 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, bool overwrite);
 221
 222 /**
 223  * uci_list_configs: List available uci config files
 224  * @ctx: uci context
 225  *
 226  * caller is responsible for freeing the allocated memory behind list
 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  * This function allows you to add directories, which contain 'overlays'
 250  * for the active config, that will never be committed.
 251  */
 252 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 253
 254 /**
 255  * uci_revert: revert all changes to a config item
 256  * @ctx: uci context
 257  * @ptr: uci pointer
 258  */
 259 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 260
 261 /**
 262  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 263  * @ctx: uci context
 264  * @stream: input stream
 265  * @str: pointer to the current line (use NULL for parsing the next line)
 266  * @result: pointer for the result
 267  */
 268 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 269
 270 /**
 271  * uci_set_backend: change the default backend
 272  * @ctx: uci context
 273  * @name: name of the backend
 274  *
 275  * The default backend is "file", which uses /etc/config for config storage
 276  */
 277 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 278
 279 /**
 280  * uci_validate_text: validate a value string for uci options
 281  * @str: value
 282  *
 283  * this function checks whether a given string is acceptable as value
 284  * for uci options
 285  */
 286 extern bool uci_validate_text(const char *str);
 287
 288
 289 /**
 290  * uci_add_hook: add a uci hook
 291  * @ctx: uci context
 292  * @ops: uci hook ops
 293  *
 294  * NB: allocated and freed by the caller
 295  */
 296 extern int uci_add_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 297
 298 /**
 299  * uci_remove_hook: remove a uci hook
 300  * @ctx: uci context
 301  * @ops: uci hook ops
 302  */
 303 extern int uci_remove_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 304
 305 /**
 306  * uci_load_plugin: load an uci plugin
 307  * @ctx: uci context
 308  * @filename: path to the uci plugin
 309  *
 310  * NB: plugin will be unloaded automatically when the context is freed
 311  */
 312 int uci_load_plugin(struct uci_context *ctx, const char *filename);
 313
 314 /**
 315  * uci_load_plugins: load all uci plugins from a directory
 316  * @ctx: uci context
 317  * @pattern: pattern of uci plugin files (optional)
 318  *
 319  * if pattern is NULL, then uci_load_plugins will call uci_load_plugin
 320  * for uci_*.so in <prefix>/lib/
 321  */
 322 int uci_load_plugins(struct uci_context *ctx, const char *pattern);
 323
 324
 325 /* UCI data structures */
 326 enum uci_type {
 327         UCI_TYPE_UNSPEC = 0,
 328         UCI_TYPE_HISTORY = 1,
 329         UCI_TYPE_PACKAGE = 2,
 330         UCI_TYPE_SECTION = 3,
 331         UCI_TYPE_OPTION = 4,
 332         UCI_TYPE_PATH = 5,
 333         UCI_TYPE_BACKEND = 6,
 334         UCI_TYPE_ITEM = 7,
 335         UCI_TYPE_HOOK = 8,
 336         UCI_TYPE_PLUGIN = 9,
 337 };
 338
 339 enum uci_option_type {
 340         UCI_TYPE_STRING = 0,
 341         UCI_TYPE_LIST = 1,
 342 };
 343
 344 enum uci_flags {
 345         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 346         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 347         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 348         UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
 349 };
 350
 351 struct uci_element
 352 {
 353         struct uci_list list;
 354         enum uci_type type;
 355         char *name;
 356 };
 357
 358 struct uci_backend
 359 {
 360         struct uci_element e;
 361         char **(*list_configs)(struct uci_context *ctx);
 362         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 363         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 364
 365         /* private: */
 366         const void *ptr;
 367         void *priv;
 368 };
 369
 370 struct uci_context
 371 {
 372         /* list of config packages */
 373         struct uci_list root;
 374
 375         /* parser context, use for error handling only */
 376         struct uci_parse_context *pctx;
 377
 378         /* backend for import and export */
 379         struct uci_backend *backend;
 380         struct uci_list backends;
 381
 382         /* uci runtime flags */
 383         enum uci_flags flags;
 384
 385         char *confdir;
 386         char *savedir;
 387
 388         /* search path for history files */
 389         struct uci_list history_path;
 390
 391         /* private: */
 392         int err;
 393         const char *func;
 394         jmp_buf trap;
 395         bool internal, nested;
 396         char *buf;
 397         int bufsz;
 398
 399         struct uci_list hooks;
 400         struct uci_list plugins;
 401 };
 402
 403 struct uci_package
 404 {
 405         struct uci_element e;
 406         struct uci_list sections;
 407         struct uci_context *ctx;
 408         bool has_history;
 409         char *path;
 410
 411         /* private: */
 412         struct uci_backend *backend;
 413         void *priv;
 414         int n_section;
 415         struct uci_list history;
 416         struct uci_list saved_history;
 417 };
 418
 419 struct uci_section
 420 {
 421         struct uci_element e;
 422         struct uci_list options;
 423         struct uci_package *package;
 424         bool anonymous;
 425         char *type;
 426 };
 427
 428 struct uci_option
 429 {
 430         struct uci_element e;
 431         struct uci_section *section;
 432         enum uci_option_type type;
 433         union {
 434                 struct uci_list list;
 435                 char *string;
 436         } v;
 437 };
 438
 439 enum uci_command {
 440         UCI_CMD_ADD,
 441         UCI_CMD_REMOVE,
 442         UCI_CMD_CHANGE,
 443         UCI_CMD_RENAME,
 444         UCI_CMD_REORDER,
 445         UCI_CMD_LIST_ADD,
 446 };
 447
 448 struct uci_history
 449 {
 450         struct uci_element e;
 451         enum uci_command cmd;
 452         char *section;
 453         char *value;
 454 };
 455
 456 struct uci_ptr
 457 {
 458         enum uci_type target;
 459         enum {
 460                 UCI_LOOKUP_DONE =     (1 << 0),
 461                 UCI_LOOKUP_COMPLETE = (1 << 1),
 462                 UCI_LOOKUP_EXTENDED = (1 << 2),
 463         } flags;
 464
 465         struct uci_package *p;
 466         struct uci_section *s;
 467         struct uci_option *o;
 468         struct uci_element *last;
 469
 470         const char *package;
 471         const char *section;
 472         const char *option;
 473         const char *value;
 474 };
 475
 476 struct uci_hook_ops
 477 {
 478         void (*load)(const struct uci_hook_ops *ops, struct uci_package *p);
 479         void (*set)(const struct uci_hook_ops *ops, struct uci_package *p, struct uci_history *e);
 480 };
 481
 482 struct uci_hook
 483 {
 484         struct uci_element e;
 485         const struct uci_hook_ops *ops;
 486 };
 487
 488 struct uci_plugin_ops
 489 {
 490         int (*attach)(struct uci_context *ctx);
 491         void (*detach)(struct uci_context *ctx);
 492 };
 493
 494 struct uci_plugin
 495 {
 496         struct uci_element e;
 497         const struct uci_plugin_ops *ops;
 498         void *dlh;
 499 };
 500
 501
 502 /* linked list handling */
 503 #ifndef offsetof
 504 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 505 #endif
 506
 507 /**
 508  * container_of - cast a member of a structure out to the containing structure
 509  * @ptr:    the pointer to the member.
 510  * @type:   the type of the container struct this is embedded in.
 511  * @member: the name of the member within the struct.
 512  */
 513 #ifndef container_of
 514 #define container_of(ptr, type, member) \
 515         ((type *) ((char *)ptr - offsetof(type,member)))
 516 #endif
 517
 518
 519 /**
 520  * uci_list_entry: casts an uci_list pointer to the containing struct.
 521  * @_type: config, section or option
 522  * @_ptr: pointer to the uci_list struct
 523  */
 524 #define list_to_element(ptr) \
 525         container_of(ptr, struct uci_element, list)
 526
 527 /**
 528  * uci_foreach_entry: loop through a list of uci elements
 529  * @_list: pointer to the uci_list struct
 530  * @_ptr: iteration variable, struct uci_element
 531  *
 532  * use like a for loop, e.g:
 533  *   uci_foreach(&list, p) {
 534  *      ...
 535  *   }
 536  */
 537 #define uci_foreach_element(_list, _ptr)                \
 538         for(_ptr = list_to_element((_list)->next);      \
 539                 &_ptr->list != (_list);                 \
 540                 _ptr = list_to_element(_ptr->list.next))
 541
 542 /**
 543  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 544  * @_list: pointer to the uci_list struct
 545  * @_tmp: temporary variable, struct uci_element *
 546  * @_ptr: iteration variable, struct uci_element *
 547  *
 548  * use like a for loop, e.g:
 549  *   uci_foreach(&list, p) {
 550  *      ...
 551  *   }
 552  */
 553 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 554         for(_ptr = list_to_element((_list)->next),              \
 555                 _tmp = list_to_element(_ptr->list.next);        \
 556                 &_ptr->list != (_list);                 \
 557                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 558
 559 /**
 560  * uci_list_empty: returns true if a list is empty
 561  * @list: list head
 562  */
 563 #define uci_list_empty(list) ((list)->next == (list))
 564
 565 /* wrappers for dynamic type handling */
 566 #define uci_type_backend UCI_TYPE_BACKEND
 567 #define uci_type_history UCI_TYPE_HISTORY
 568 #define uci_type_package UCI_TYPE_PACKAGE
 569 #define uci_type_section UCI_TYPE_SECTION
 570 #define uci_type_option UCI_TYPE_OPTION
 571 #define uci_type_hook UCI_TYPE_HOOK
 572 #define uci_type_plugin UCI_TYPE_PLUGIN
 573
 574 /* element typecasting */
 575 #ifdef UCI_DEBUG_TYPECAST
 576 static const char *uci_typestr[] = {
 577         [uci_type_backend] = "backend",
 578         [uci_type_history] = "history",
 579         [uci_type_package] = "package",
 580         [uci_type_section] = "section",
 581         [uci_type_option] = "option",
 582         [uci_type_hook] = "hook",
 583         [uci_type_plugin] = "plugin",
 584 };
 585
 586 static void uci_typecast_error(int from, int to)
 587 {
 588         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 589 }
 590
 591 #define BUILD_CAST(_type) \
 592         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 593         { \
 594                 if (e->type != uci_type_ ## _type) { \
 595                         uci_typecast_error(e->type, uci_type_ ## _type); \
 596                 } \
 597                 return (struct uci_ ## _type *) e; \
 598         }
 599
 600 BUILD_CAST(backend)
 601 BUILD_CAST(history)
 602 BUILD_CAST(package)
 603 BUILD_CAST(section)
 604 BUILD_CAST(option)
 605 BUILD_CAST(hook)
 606 BUILD_CAST(plugin)
 607
 608 #else
 609 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 610 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 611 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 612 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 613 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 614 #define uci_to_hook(ptr)    container_of(ptr, struct uci_hook, e)
 615 #define uci_to_plugin(ptr)  container_of(ptr, struct uci_plugin, e)
 616 #endif
 617
 618 /**
 619  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 620  * @ctx: uci context
 621  * @type: {package,section,option}
 622  * @name: string containing the name of the element
 623  * @datasize: additional buffer size to reserve at the end of the struct
 624  */
 625 #define uci_alloc_element(ctx, type, name, datasize) \
 626         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 627
 628 #define uci_dataptr(ptr) \
 629         (((char *) ptr) + sizeof(*ptr))
 630
 631 #endif