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