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