16c69665f6eabfe5bb6e6f2296b1ce1fbca6eeb6
[project/uci.git] / 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_element;
59 struct uci_package;
60 struct uci_section;
61 struct uci_option;
62 struct uci_history;
63 struct uci_context;
64 struct uci_backend;
65 struct uci_parse_context;
66
67
68 /**
69 * uci_parse_tuple: Parse an uci tuple
70 * @ctx: uci context
71 * @str: input string
72 * @package: output package pointer
73 * @section: output section pointer
74 * @option: output option pointer
75 * @value: output value pointer
76 *
77 * format: <package>[.<section>[.<option>]][=<value>]
78 */
79 extern int uci_parse_tuple(struct uci_context *ctx, char *str, char **package, char **section, char **option, char **value);
80
81 /**
82 * uci_alloc_context: Allocate a new uci context
83 */
84 extern struct uci_context *uci_alloc_context(void);
85
86 /**
87 * uci_free_context: Free the uci context including all of its data
88 */
89 extern void uci_free_context(struct uci_context *ctx);
90
91 /**
92 * uci_perror: Print the last uci error that occured
93 * @ctx: uci context
94 * @str: string to print before the error message
95 */
96 extern void uci_perror(struct uci_context *ctx, 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: Look up an uci element
139 *
140 * @ctx: uci context
141 * @res: where to store the result
142 * @package: uci_package struct
143 * @section: config section (optional)
144 * @option: option to search for (optional)
145 *
146 * If section is omitted, then a pointer to the config package is returned
147 * If option is omitted, then a pointer to the config section is returned
148 */
149 extern int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *package, const char *section, const char *option);
150
151 /**
152 * uci_lookup_ext: Extended lookup for an uci element
153 *
154 * @ctx: uci context
155 * @res: where to store the result
156 * @ptr: uci pointer tuple
157 *
158 * Looks up an element using the extended syntax, which is a superset of what
159 * uci_parse_tuple accepts. It can look up sections by an index with an optional
160 * type.
161 *
162 * Examples:
163 * network.@interface[0].ifname ('ifname' option of the first interface section)
164 * network.@interface[-1] (last interface section)
165 * Note: uci_lookup_ext will automatically load a config package if necessary
166 */
167 extern int uci_lookup_ext(struct uci_context *ctx, struct uci_element **res, char *ptr);
168
169 /**
170 * uci_add_section: Add an unnamed section
171 * @ctx: uci context
172 * @p: package to add the section to
173 * @type: section type
174 * @res: pointer to store a reference to the new section in
175 */
176 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
177
178 /**
179 * uci_set_element_value: Replace an element's value with a new one
180 * @ctx: uci context
181 * @element: pointer to an uci_element struct pointer
182 * @value: new value
183 *
184 * Only valid for uci_option and uci_section. Will replace the type string
185 * when used with an uci_section
186 */
187 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, const char *value);
188
189 /**
190 * uci_set: Set an element's value; create the element if necessary
191 * @ctx: uci context
192 * @package: package name
193 * @section: section name
194 * @option: option name
195 * @value: value (option) or type (section)
196 * @result: store the updated element in this variable (optional)
197 */
198 extern int uci_set(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option, const char *value, struct uci_element **result);
199
200 /**
201 * uci_rename: Rename an element
202 * @ctx: uci context
203 * @package: package name
204 * @section: section name
205 * @option: option name
206 * @name: new name
207 */
208 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
209
210 /**
211 * uci_delete_element: Delete a section or option
212 * @ctx: uci context
213 * @e: element (section or option)
214 */
215 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
216
217 /**
218 * uci_delete: Delete a section or option
219 * @ctx: uci context
220 * @p: uci package
221 * @section: section name
222 * @option: option name (optional)
223 */
224 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option);
225
226 /**
227 * uci_save: save change history for a package
228 * @ctx: uci context
229 * @p: uci_package struct
230 */
231 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
232
233 /**
234 * uci_commit: commit changes to a package
235 * @ctx: uci context
236 * @p: uci_package struct pointer
237 * @overwrite: overwrite existing config data and flush history
238 *
239 * committing may reload the whole uci_package data,
240 * the supplied pointer is updated accordingly
241 */
242 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
243
244 /**
245 * uci_list_configs: List available uci config files
246 * @ctx: uci context
247 *
248 * caller is responsible for freeing the allocated memory behind list
249 */
250 extern int uci_list_configs(struct uci_context *ctx, char ***list);
251
252 /**
253 * uci_set_savedir: override the default history save directory
254 * @ctx: uci context
255 * @dir: directory name
256 */
257 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
258
259 /**
260 * uci_set_savedir: override the default config storage directory
261 * @ctx: uci context
262 * @dir: directory name
263 */
264 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
265
266 /**
267 * uci_add_history_path: add a directory to the search path for change history files
268 * @ctx: uci context
269 * @dir: directory name
270 *
271 * This function allows you to add directories, which contain 'overlays'
272 * for the active config, that will never be committed.
273 */
274 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
275
276 /**
277 * uci_revert: revert all changes to a config item
278 * @ctx: uci context
279 * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
280 * @section: section name (optional)
281 * @option option name (optional)
282 */
283 extern int uci_revert(struct uci_context *ctx, struct uci_package **p, const char *section, const char *option);
284
285 /**
286 * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
287 * @ctx: uci context
288 * @stream: input stream
289 * @str: pointer to the current line (use NULL for parsing the next line)
290 * @result: pointer for the result
291 */
292 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
293
294 /**
295 * uci_set_backend: change the default backend
296 * @ctx: uci context
297 * @name: name of the backend
298 *
299 * The default backend is "file", which uses /etc/config for config storage
300 */
301 extern int uci_set_backend(struct uci_context *ctx, const char *name);
302
303 /**
304 * uci_validate_text: validate a value string for uci options
305 * @str: value
306 *
307 * this function checks whether a given string is acceptable as value
308 * for uci options
309 */
310 extern bool uci_validate_text(const char *str);
311
312 /* UCI data structures */
313 enum uci_type {
314 UCI_TYPE_HISTORY = 0,
315 UCI_TYPE_PACKAGE = 1,
316 UCI_TYPE_SECTION = 2,
317 UCI_TYPE_OPTION = 3,
318 UCI_TYPE_PATH = 4,
319 UCI_TYPE_BACKEND = 5,
320 };
321
322 enum uci_flags {
323 UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
324 UCI_FLAG_PERROR = (1 << 1), /* print parser error messages */
325 UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
326 UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
327 };
328
329 struct uci_element
330 {
331 struct uci_list list;
332 enum uci_type type;
333 char *name;
334 };
335
336 struct uci_backend
337 {
338 struct uci_element e;
339 char **(*list_configs)(struct uci_context *ctx);
340 struct uci_package *(*load)(struct uci_context *ctx, const char *name);
341 void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
342
343 /* private: */
344 const void *ptr;
345 void *priv;
346 };
347
348 struct uci_context
349 {
350 /* list of config packages */
351 struct uci_list root;
352
353 /* parser context, use for error handling only */
354 struct uci_parse_context *pctx;
355
356 /* backend for import and export */
357 struct uci_backend *backend;
358 struct uci_list backends;
359
360 /* uci runtime flags */
361 enum uci_flags flags;
362
363 char *confdir;
364 char *savedir;
365
366 /* search path for history files */
367 struct uci_list history_path;
368
369 /* private: */
370 int err;
371 const char *func;
372 jmp_buf trap;
373 bool internal;
374 char *buf;
375 int bufsz;
376 };
377
378 struct uci_package
379 {
380 struct uci_element e;
381 struct uci_list sections;
382 struct uci_context *ctx;
383 bool has_history;
384 char *path;
385
386 /* private: */
387 struct uci_backend *backend;
388 void *priv;
389 int n_section;
390 struct uci_list history;
391 struct uci_list saved_history;
392 };
393
394 struct uci_section
395 {
396 struct uci_element e;
397 struct uci_list options;
398 struct uci_package *package;
399 bool anonymous;
400 char *type;
401 };
402
403 struct uci_option
404 {
405 struct uci_element e;
406 struct uci_section *section;
407 char *value;
408 };
409
410 enum uci_command {
411 UCI_CMD_ADD,
412 UCI_CMD_REMOVE,
413 UCI_CMD_CHANGE,
414 UCI_CMD_RENAME
415 };
416
417 struct uci_history
418 {
419 struct uci_element e;
420 enum uci_command cmd;
421 char *section;
422 char *value;
423 };
424
425
426 /* linked list handling */
427 #ifndef offsetof
428 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
429 #endif
430
431 /**
432 * container_of - cast a member of a structure out to the containing structure
433 * @ptr: the pointer to the member.
434 * @type: the type of the container struct this is embedded in.
435 * @member: the name of the member within the struct.
436 */
437 #define container_of(ptr, type, member) \
438 ((type *) ((char *)ptr - offsetof(type,member)))
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