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_reorder: Reposition a section
 182  * @ctx: uci context
 183  * @s: uci section to reposition
 184  * @pos: new position in the section list
 185  */
 186 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
 187
 188 /**
 189  * uci_rename: Rename an element
 190  * @ctx: uci context
 191  * @ptr: uci pointer (with value)
 192  */
 193 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
 194
 195 /**
 196  * uci_delete: Delete a section or option
 197  * @ctx: uci context
 198  * @ptr: uci pointer
 199  */
 200 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
 201
 202 /**
 203  * uci_save: save change history for a package
 204  * @ctx: uci context
 205  * @p: uci_package struct
 206  */
 207 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
 208
 209 /**
 210  * uci_commit: commit changes to a package
 211  * @ctx: uci context
 212  * @p: uci_package struct pointer
 213  * @overwrite: overwrite existing config data and flush history
 214  *
 215  * committing may reload the whole uci_package data,
 216  * the supplied pointer is updated accordingly
 217  */
 218 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 219
 220 /**
 221  * uci_list_configs: List available uci config files
 222  * @ctx: uci context
 223  *
 224  * caller is responsible for freeing the allocated memory behind list
 225  */
 226 extern int uci_list_configs(struct uci_context *ctx, char ***list);
 227
 228 /**
 229  * uci_set_savedir: override the default history save directory
 230  * @ctx: uci context
 231  * @dir: directory name
 232  */
 233 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
 234
 235 /**
 236  * uci_set_savedir: override the default config storage directory
 237  * @ctx: uci context
 238  * @dir: directory name
 239  */
 240 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
 241
 242 /**
 243  * uci_add_history_path: add a directory to the search path for change history files
 244  * @ctx: uci context
 245  * @dir: directory name
 246  *
 247  * This function allows you to add directories, which contain 'overlays'
 248  * for the active config, that will never be committed.
 249  */
 250 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
 251
 252 /**
 253  * uci_revert: revert all changes to a config item
 254  * @ctx: uci context
 255  * @ptr: uci pointer
 256  */
 257 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
 258
 259 /**
 260  * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
 261  * @ctx: uci context
 262  * @stream: input stream
 263  * @str: pointer to the current line (use NULL for parsing the next line)
 264  * @result: pointer for the result
 265  */
 266 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
 267
 268 /**
 269  * uci_set_backend: change the default backend
 270  * @ctx: uci context
 271  * @name: name of the backend
 272  *
 273  * The default backend is "file", which uses /etc/config for config storage
 274  */
 275 extern int uci_set_backend(struct uci_context *ctx, const char *name);
 276
 277 /**
 278  * uci_validate_text: validate a value string for uci options
 279  * @str: value
 280  *
 281  * this function checks whether a given string is acceptable as value
 282  * for uci options
 283  */
 284 extern bool uci_validate_text(const char *str);
 285
 286 /* UCI data structures */
 287 enum uci_type {
 288         UCI_TYPE_UNSPEC = 0,
 289         UCI_TYPE_HISTORY = 1,
 290         UCI_TYPE_PACKAGE = 2,
 291         UCI_TYPE_SECTION = 3,
 292         UCI_TYPE_OPTION = 4,
 293         UCI_TYPE_PATH = 5,
 294         UCI_TYPE_BACKEND = 6,
 295         UCI_TYPE_ITEM = 7,
 296 };
 297
 298 enum uci_option_type {
 299         UCI_TYPE_STRING = 0,
 300         UCI_TYPE_LIST = 1,
 301 };
 302
 303 enum uci_flags {
 304         UCI_FLAG_STRICT =        (1 << 0), /* strict mode for the parser */
 305         UCI_FLAG_PERROR =        (1 << 1), /* print parser error messages */
 306         UCI_FLAG_EXPORT_NAME =   (1 << 2), /* when exporting, name unnamed sections */
 307         UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
 308 };
 309
 310 struct uci_element
 311 {
 312         struct uci_list list;
 313         enum uci_type type;
 314         char *name;
 315 };
 316
 317 struct uci_backend
 318 {
 319         struct uci_element e;
 320         char **(*list_configs)(struct uci_context *ctx);
 321         struct uci_package *(*load)(struct uci_context *ctx, const char *name);
 322         void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
 323
 324         /* private: */
 325         const void *ptr;
 326         void *priv;
 327 };
 328
 329 struct uci_context
 330 {
 331         /* list of config packages */
 332         struct uci_list root;
 333
 334         /* parser context, use for error handling only */
 335         struct uci_parse_context *pctx;
 336
 337         /* backend for import and export */
 338         struct uci_backend *backend;
 339         struct uci_list backends;
 340
 341         /* uci runtime flags */
 342         enum uci_flags flags;
 343
 344         char *confdir;
 345         char *savedir;
 346
 347         /* search path for history files */
 348         struct uci_list history_path;
 349
 350         /* private: */
 351         int err;
 352         const char *func;
 353         jmp_buf trap;
 354         bool internal, nested;
 355         char *buf;
 356         int bufsz;
 357 };
 358
 359 struct uci_package
 360 {
 361         struct uci_element e;
 362         struct uci_list sections;
 363         struct uci_context *ctx;
 364         bool has_history;
 365         char *path;
 366
 367         /* private: */
 368         struct uci_backend *backend;
 369         void *priv;
 370         int n_section;
 371         struct uci_list history;
 372         struct uci_list saved_history;
 373 };
 374
 375 struct uci_section
 376 {
 377         struct uci_element e;
 378         struct uci_list options;
 379         struct uci_package *package;
 380         bool anonymous;
 381         char *type;
 382 };
 383
 384 struct uci_option
 385 {
 386         struct uci_element e;
 387         struct uci_section *section;
 388         enum uci_option_type type;
 389         union {
 390                 struct uci_list list;
 391                 char *string;
 392         } v;
 393 };
 394
 395 enum uci_command {
 396         UCI_CMD_ADD,
 397         UCI_CMD_REMOVE,
 398         UCI_CMD_CHANGE,
 399         UCI_CMD_RENAME,
 400         UCI_CMD_REORDER,
 401         UCI_CMD_LIST_ADD,
 402 };
 403
 404 struct uci_history
 405 {
 406         struct uci_element e;
 407         enum uci_command cmd;
 408         char *section;
 409         char *value;
 410 };
 411
 412 struct uci_ptr
 413 {
 414         enum uci_type target;
 415         enum {
 416                 UCI_LOOKUP_DONE =     (1 << 0),
 417                 UCI_LOOKUP_COMPLETE = (1 << 1),
 418                 UCI_LOOKUP_EXTENDED = (1 << 2),
 419         } flags;
 420
 421         struct uci_package *p;
 422         struct uci_section *s;
 423         struct uci_option *o;
 424         struct uci_element *last;
 425
 426         const char *package;
 427         const char *section;
 428         const char *option;
 429         const char *value;
 430 };
 431
 432
 433 /* linked list handling */
 434 #ifndef offsetof
 435 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 436 #endif
 437
 438 /**
 439  * container_of - cast a member of a structure out to the containing structure
 440  * @ptr:    the pointer to the member.
 441  * @type:   the type of the container struct this is embedded in.
 442  * @member: the name of the member within the struct.
 443  */
 444 #ifndef container_of
 445 #define container_of(ptr, type, member) \
 446         ((type *) ((char *)ptr - offsetof(type,member)))
 447 #endif
 448
 449
 450 /**
 451  * uci_list_entry: casts an uci_list pointer to the containing struct.
 452  * @_type: config, section or option
 453  * @_ptr: pointer to the uci_list struct
 454  */
 455 #define list_to_element(ptr) \
 456         container_of(ptr, struct uci_element, list)
 457
 458 /**
 459  * uci_foreach_entry: loop through a list of uci elements
 460  * @_list: pointer to the uci_list struct
 461  * @_ptr: iteration variable, struct uci_element
 462  *
 463  * use like a for loop, e.g:
 464  *   uci_foreach(&list, p) {
 465  *      ...
 466  *   }
 467  */
 468 #define uci_foreach_element(_list, _ptr)                \
 469         for(_ptr = list_to_element((_list)->next);      \
 470                 &_ptr->list != (_list);                 \
 471                 _ptr = list_to_element(_ptr->list.next))
 472
 473 /**
 474  * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
 475  * @_list: pointer to the uci_list struct
 476  * @_tmp: temporary variable, struct uci_element *
 477  * @_ptr: iteration variable, struct uci_element *
 478  *
 479  * use like a for loop, e.g:
 480  *   uci_foreach(&list, p) {
 481  *      ...
 482  *   }
 483  */
 484 #define uci_foreach_element_safe(_list, _tmp, _ptr)             \
 485         for(_ptr = list_to_element((_list)->next),              \
 486                 _tmp = list_to_element(_ptr->list.next);        \
 487                 &_ptr->list != (_list);                 \
 488                 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
 489
 490 /**
 491  * uci_list_empty: returns true if a list is empty
 492  * @list: list head
 493  */
 494 #define uci_list_empty(list) ((list)->next == (list))
 495
 496 /* wrappers for dynamic type handling */
 497 #define uci_type_backend UCI_TYPE_BACKEND
 498 #define uci_type_history UCI_TYPE_HISTORY
 499 #define uci_type_package UCI_TYPE_PACKAGE
 500 #define uci_type_section UCI_TYPE_SECTION
 501 #define uci_type_option UCI_TYPE_OPTION
 502
 503 /* element typecasting */
 504 #ifdef UCI_DEBUG_TYPECAST
 505 static const char *uci_typestr[] = {
 506         [uci_type_backend] = "backend",
 507         [uci_type_history] = "history",
 508         [uci_type_package] = "package",
 509         [uci_type_section] = "section",
 510         [uci_type_option] = "option",
 511 };
 512
 513 static void uci_typecast_error(int from, int to)
 514 {
 515         fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
 516 }
 517
 518 #define BUILD_CAST(_type) \
 519         static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
 520         { \
 521                 if (e->type != uci_type_ ## _type) { \
 522                         uci_typecast_error(e->type, uci_type_ ## _type); \
 523                 } \
 524                 return (struct uci_ ## _type *) e; \
 525         }
 526
 527 BUILD_CAST(backend)
 528 BUILD_CAST(history)
 529 BUILD_CAST(package)
 530 BUILD_CAST(section)
 531 BUILD_CAST(option)
 532
 533 #else
 534 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
 535 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
 536 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
 537 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
 538 #define uci_to_option(ptr)  container_of(ptr, struct uci_option, e)
 539 #endif
 540
 541 /**
 542  * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
 543  * @ctx: uci context
 544  * @type: {package,section,option}
 545  * @name: string containing the name of the element
 546  * @datasize: additional buffer size to reserve at the end of the struct
 547  */
 548 #define uci_alloc_element(ctx, type, name, datasize) \
 549         uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
 550
 551 #define uci_dataptr(ptr) \
 552         (((char *) ptr) + sizeof(*ptr))
 553
 554 #endif