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_ptr will automatically load a config package if necessary
 151  * @str must not be constant, as it will be modified and used for the strings inside @ptr,
 152  * thus it must also be available as long as @ptr is in use.
 153  */
 154 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
 155
 156 /**
 157  * uci_add_section: Add an unnamed section
 158  * @ctx: uci context
 159  * @p: package to add the section to
 160  * @type: section type
 161  * @res: pointer to store a reference to the new section in
 162  */
 163 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
 164
 165 /**
 166  * uci_set: Set an element's value; create the element if necessary
 167  * @ctx: uci context
 168  * @ptr: uci pointer
 169  *
 170  * The updated/created element is stored in ptr->last
 171  */
 172 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
 173
 174 /**
 175  * uci_add_list: Append a string to an element list
 176  * @ctx: uci context
 177  * @ptr: uci pointer (with value)
 178  *
 179  * Note: if the given option already contains a string value,
 180  * it will be converted to an 1-element-list before appending the next element
 181  */
 182 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
 183
 184 /**
 185  * uci_reorder: Reposition a section
 186  * @ctx: uci context
 187  * @s: uci section to reposition
 188  * @pos: new position in the section list
 189  */
 190 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
 191
 192 /**
 193  * uci_rename: Rename an element
 194  * @ctx: uci context
 195  * @ptr: uci pointer (with value)
 196  */
 197 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
 198
 199 /**
 200  * uci_delete: Delete a section or option
 201  * @ctx: uci context
 202  * @ptr: uci pointer
 203  */
 204 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
 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  * caller is responsible for freeing the allocated memory behind list
 229  */
 230 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 231
 232 /**
 233  * uci_set_savedir: override the default history save directory
 234  * @ctx: uci context
 235  * @dir: directory name
 236  */
 237 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 238
 239 /**
 240  * uci_set_savedir: override the default config storage directory
 241  * @ctx: uci context
 242  * @dir: directory name
 243  */
 244 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 245
 246 /**
 247  * uci_add_history_path: add a directory to the search path for change history files
 248  * @ctx: uci context
 249  * @dir: directory name
 250  *
 251  * This function allows you to add directories, which contain 'overlays'
 252  * for the active config, that will never be committed.
 253  */
 254 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 255
 256 /**
 257  * uci_revert: revert all changes to a config item
 258  * @ctx: uci context
 259  * @ptr: uci pointer
 260  */
 261 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 262
 263 /**
 264  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 265  * @ctx: uci context
 266  * @stream: input stream
 267  * @str: pointer to the current line (use NULL for parsing the next line)
 268  * @result: pointer for the result
 269  */
 270 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 271
 272 /**
 273  * uci_set_backend: change the default backend
 274  * @ctx: uci context
 275  * @name: name of the backend
 276  *
 277  * The default backend is "file", which uses /etc/config for config storage
 278  */
 279 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 280
 281 /**
 282  * uci_validate_text: validate a value string for uci options
 283  * @str: value
 284  *
 285  * this function checks whether a given string is acceptable as value
 286  * for uci options
 287  */
 288 extern bool uci_validate_text(const char *str);
 289
 290
 291 /**
 292  * uci_add_hook: add a uci hook
 293  * @ctx: uci context
 294  * @ops: uci hook ops
 295  *
 296  * NB: allocated and freed by the caller
 297  */
 298 extern int uci_add_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 299
 300 /**
 301  * uci_remove_hook: remove a uci hook
 302  * @ctx: uci context
 303  * @ops: uci hook ops
 304  */
 305 extern int uci_remove_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
 306
 307 /**
 308  * uci_load_plugin: load an uci plugin
 309  * @ctx: uci context
 310  * @filename: path to the uci plugin
 311  *
 312  * NB: plugin will be unloaded automatically when the context is freed
 313  */
 314 int uci_load_plugin(struct uci_context *ctx, const char *filename);
 315
 316 /**
 317  * uci_load_plugins: load all uci plugins from a directory
 318  * @ctx: uci context
 319  * @pattern: pattern of uci plugin files (optional)
 320  *
 321  * if pattern is NULL, then uci_load_plugins will call uci_load_plugin
 322  * for uci_*.so in <prefix>/lib/
 323  */
 324 int uci_load_plugins(struct uci_context *ctx, const char *pattern);
 325
 326
 327 /* UCI data structures */
 328 enum uci_type {
 329         UCI_TYPE_UNSPEC = 0,
 330         UCI_TYPE_HISTORY = 1,
 331         UCI_TYPE_PACKAGE = 2,
 332         UCI_TYPE_SECTION = 3,
 333         UCI_TYPE_OPTION = 4,
 334         UCI_TYPE_PATH = 5,
 335         UCI_TYPE_BACKEND = 6,
 336         UCI_TYPE_ITEM = 7,
 337         UCI_TYPE_HOOK = 8,
 338         UCI_TYPE_PLUGIN = 9,
 339 };
 340
 341 enum uci_option_type {
 342         UCI_TYPE_STRING = 0,
 343         UCI_TYPE_LIST = 1,
 344 };
 345
 346 enum uci_flags {
 347         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 348         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 349         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 350         UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
 351 };
 352
 353 struct uci_element
 354 {
 355         struct uci_list list;
 356         enum uci_type type;
 357         char *name;
 358 };
 359
 360 struct uci_backend
 361 {
 362         struct uci_element e;
 363         char **(*list_configs)(struct uci_context *ctx);
 364         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 365         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 366
 367         /* private: */
 368         const void *ptr;
 369         void *priv;
 370 };
 371
 372 struct uci_context
 373 {
 374         /* list of config packages */
 375         struct uci_list root;
 376
 377         /* parser context, use for error handling only */
 378         struct uci_parse_context *pctx;
 379
 380         /* backend for import and export */
 381         struct uci_backend *backend;
 382         struct uci_list backends;
 383
 384         /* uci runtime flags */
 385         enum uci_flags flags;
 386
 387         char *confdir;
 388         char *savedir;
 389
 390         /* search path for history files */
 391         struct uci_list history_path;
 392
 393         /* private: */
 394         int err;
 395         const char *func;
 396         jmp_buf trap;
 397         bool internal, nested;
 398         char *buf;
 399         int bufsz;
 400
 401         struct uci_list hooks;
 402         struct uci_list plugins;
 403 };
 404
 405 struct uci_package
 406 {
 407         struct uci_element e;
 408         struct uci_list sections;
 409         struct uci_context *ctx;
 410         bool has_history;
 411         char *path;
 412
 413         /* private: */
 414         struct uci_backend *backend;
 415         void *priv;
 416         int n_section;
 417         struct uci_list history;
 418         struct uci_list saved_history;
 419 };
 420
 421 struct uci_section
 422 {
 423         struct uci_element e;
 424         struct uci_list options;
 425         struct uci_package *package;
 426         bool anonymous;
 427         char *type;
 428 };
 429
 430 struct uci_option
 431 {
 432         struct uci_element e;
 433         struct uci_section *section;
 434         enum uci_option_type type;
 435         union {
 436                 struct uci_list list;
 437                 char *string;
 438         } v;
 439 };
 440
 441 enum uci_command {
 442         UCI_CMD_ADD,
 443         UCI_CMD_REMOVE,
 444         UCI_CMD_CHANGE,
 445         UCI_CMD_RENAME,
 446         UCI_CMD_REORDER,
 447         UCI_CMD_LIST_ADD,
 448 };
 449
 450 struct uci_history
 451 {
 452         struct uci_element e;
 453         enum uci_command cmd;
 454         char *section;
 455         char *value;
 456 };
 457
 458 struct uci_ptr
 459 {
 460         enum uci_type target;
 461         enum {
 462                 UCI_LOOKUP_DONE =     (1 << 0),
 463                 UCI_LOOKUP_COMPLETE = (1 << 1),
 464                 UCI_LOOKUP_EXTENDED = (1 << 2),
 465         } flags;
 466
 467         struct uci_package *p;
 468         struct uci_section *s;
 469         struct uci_option *o;
 470         struct uci_element *last;
 471
 472         const char *package;
 473         const char *section;
 474         const char *option;
 475         const char *value;
 476 };
 477
 478 struct uci_hook_ops
 479 {
 480         void (*load)(const struct uci_hook_ops *ops, struct uci_package *p);
 481         void (*set)(const struct uci_hook_ops *ops, struct uci_package *p, struct uci_history *e);
 482 };
 483
 484 struct uci_hook
 485 {
 486         struct uci_element e;
 487         const struct uci_hook_ops *ops;
 488 };
 489
 490 struct uci_plugin_ops
 491 {
 492         int (*attach)(struct uci_context *ctx);
 493         void (*detach)(struct uci_context *ctx);
 494 };
 495
 496 struct uci_plugin
 497 {
 498         struct uci_element e;
 499         const struct uci_plugin_ops *ops;
 500         void *dlh;
 501 };
 502
 503
 504 /* linked list handling */
 505 #ifndef offsetof
 506 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 507 #endif
 508
 509 /**
 510  * container_of - cast a member of a structure out to the containing structure
 511  * @ptr:    the pointer to the member.
 512  * @type:   the type of the container struct this is embedded in.
 513  * @member: the name of the member within the struct.
 514  */
 515 #ifndef container_of
 516 #define container_of(ptr, type, member) \
 517         ((type *) ((char *)ptr - offsetof(type,member)))
 518 #endif
 519
 520
 521 /**
 522  * uci_list_entry: casts an uci_list pointer to the containing struct.
 523  * @_type: config, section or option
 524  * @_ptr: pointer to the uci_list struct
 525  */
 526 #define list_to_element(ptr) \
 527         container_of(ptr, struct uci_element, list)
 528
 529 /**
 530  * uci_foreach_entry: loop through a list of uci elements
 531  * @_list: pointer to the uci_list struct
 532  * @_ptr: iteration variable, struct uci_element
 533  *
 534  * use like a for loop, e.g:
 535  *   uci_foreach(&list, p) {
 536  *      ...
 537  *   }
 538  */
 539 #define uci_foreach_element(_list, _ptr)                \
 540         for(_ptr = list_to_element((_list)->next);      \
 541                 &_ptr->list != (_list);                 \
 542                 _ptr = list_to_element(_ptr->list.next))
 543
 544 /**
 545  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 546  * @_list: pointer to the uci_list struct
 547  * @_tmp: temporary variable, struct uci_element *
 548  * @_ptr: iteration variable, struct uci_element *
 549  *
 550  * use like a for loop, e.g:
 551  *   uci_foreach(&list, p) {
 552  *      ...
 553  *   }
 554  */
 555 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 556         for(_ptr = list_to_element((_list)->next),              \
 557                 _tmp = list_to_element(_ptr->list.next);        \
 558                 &_ptr->list != (_list);                 \
 559                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 560
 561 /**
 562  * uci_list_empty: returns true if a list is empty
 563  * @list: list head
 564  */
 565 #define uci_list_empty(list) ((list)->next == (list))
 566
 567 /* wrappers for dynamic type handling */
 568 #define uci_type_backend UCI_TYPE_BACKEND
 569 #define uci_type_history UCI_TYPE_HISTORY
 570 #define uci_type_package UCI_TYPE_PACKAGE
 571 #define uci_type_section UCI_TYPE_SECTION
 572 #define uci_type_option UCI_TYPE_OPTION
 573 #define uci_type_hook UCI_TYPE_HOOK
 574 #define uci_type_plugin UCI_TYPE_PLUGIN
 575
 576 /* element typecasting */
 577 #ifdef UCI_DEBUG_TYPECAST
 578 static const char *uci_typestr[] = {
 579         [uci_type_backend] = "backend",
 580         [uci_type_history] = "history",
 581         [uci_type_package] = "package",
 582         [uci_type_section] = "section",
 583         [uci_type_option] = "option",
 584         [uci_type_hook] = "hook",
 585         [uci_type_plugin] = "plugin",
 586 };
 587
 588 static void uci_typecast_error(int from, int to)
 589 {
 590         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 591 }
 592
 593 #define BUILD_CAST(_type) \
 594         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 595         { \
 596                 if (e->type != uci_type_ ## _type) { \
 597                         uci_typecast_error(e->type, uci_type_ ## _type); \
 598                 } \
 599                 return (struct uci_ ## _type *) e; \
 600         }
 601
 602 BUILD_CAST(backend)
 603 BUILD_CAST(history)
 604 BUILD_CAST(package)
 605 BUILD_CAST(section)
 606 BUILD_CAST(option)
 607 BUILD_CAST(hook)
 608 BUILD_CAST(plugin)
 609
 610 #else
 611 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 612 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 613 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 614 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 615 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 616 #define uci_to_hook(ptr)    container_of(ptr, struct uci_hook, e)
 617 #define uci_to_plugin(ptr)  container_of(ptr, struct uci_plugin, e)
 618 #endif
 619
 620 /**
 621  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 622  * @ctx: uci context
 623  * @type: {package,section,option}
 624  * @name: string containing the name of the element
 625  * @datasize: additional buffer size to reserve at the end of the struct
 626  */
 627 #define uci_alloc_element(ctx, type, name, datasize) \
 628         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 629
 630 #define uci_dataptr(ptr) \
 631         (((char *) ptr) + sizeof(*ptr))
 632
 633 #endif