be816fd95ca5cc64578c0a2521a8a223bb87c833
[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_add_section: Add an unnamed section
153 * @ctx: uci context
154 * @p: package to add the section to
155 * @type: section type
156 * @res: pointer to store a reference to the new section in
157 */
158 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, char *type, struct uci_section **res);
159
160 /**
161 * uci_set_element_value: Replace an element's value with a new one
162 * @ctx: uci context
163 * @element: pointer to an uci_element struct pointer
164 * @value: new value
165 *
166 * Only valid for uci_option and uci_section. Will replace the type string
167 * when used with an uci_section
168 */
169 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value);
170
171 /**
172 * uci_set: Set an element's value; create the element if necessary
173 * @ctx: uci context
174 * @package: package name
175 * @section: section name
176 * @option: option name
177 * @value: value (option) or type (section)
178 * @result: store the updated element in this variable (optional)
179 */
180 extern int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value, struct uci_element **result);
181
182 /**
183 * uci_rename: Rename an element
184 * @ctx: uci context
185 * @package: package name
186 * @section: section name
187 * @option: option name
188 * @name: new name
189 */
190 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
191
192 /**
193 * uci_delete_element: Delete a section or option
194 * @ctx: uci context
195 * @e: element (section or option)
196 */
197 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
198
199 /**
200 * uci_delete: Delete a section or option
201 * @ctx: uci context
202 * @p: uci package
203 * @section: section name
204 * @option: option name (optional)
205 */
206 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, char *section, char *option);
207
208 /**
209 * uci_save: save change history for a package
210 * @ctx: uci context
211 * @p: uci_package struct
212 */
213 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
214
215 /**
216 * uci_commit: commit changes to a package
217 * @ctx: uci context
218 * @p: uci_package struct pointer
219 * @overwrite: overwrite existing config data and flush history
220 *
221 * committing may reload the whole uci_package data,
222 * the supplied pointer is updated accordingly
223 */
224 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
225
226 /**
227 * uci_list_configs: List available uci config files
228 * @ctx: uci context
229 *
230 * caller is responsible for freeing the allocated memory behind list
231 */
232 extern int uci_list_configs(struct uci_context *ctx, char ***list);
233
234 /**
235 * uci_set_savedir: override the default history save directory
236 * @ctx: uci context
237 * @dir: directory name
238 */
239 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
240
241 /**
242 * uci_set_savedir: override the default config storage directory
243 * @ctx: uci context
244 * @dir: directory name
245 */
246 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
247
248 /**
249 * uci_add_history_path: add a directory to the search path for change history files
250 * @ctx: uci context
251 * @dir: directory name
252 *
253 * This function allows you to add directories, which contain 'overlays'
254 * for the active config, that will never be committed.
255 */
256 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
257
258 /**
259 * uci_revert: revert all changes to a config item
260 * @ctx: uci context
261 * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
262 * @section: section name (optional)
263 * @option option name (optional)
264 */
265 extern int uci_revert(struct uci_context *ctx, struct uci_package **p, const char *section, const char *option);
266
267 /**
268 * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
269 * @ctx: uci context
270 * @stream: input stream
271 * @str: pointer to the current line (use NULL for parsing the next line)
272 * @result: pointer for the result
273 */
274 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
275
276 /**
277 * uci_set_backend: change the default backend
278 * @ctx: uci context
279 * @name: name of the backend
280 *
281 * The default backend is "file", which uses /etc/config for config storage
282 */
283 extern int uci_set_backend(struct uci_context *ctx, const char *name);
284
285 /* UCI data structures */
286 enum uci_type {
287 UCI_TYPE_HISTORY = 0,
288 UCI_TYPE_PACKAGE = 1,
289 UCI_TYPE_SECTION = 2,
290 UCI_TYPE_OPTION = 3,
291 UCI_TYPE_PATH = 4,
292 UCI_TYPE_BACKEND = 5,
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;
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 char *value;
381 };
382
383 enum uci_command {
384 UCI_CMD_ADD,
385 UCI_CMD_REMOVE,
386 UCI_CMD_CHANGE,
387 UCI_CMD_RENAME
388 };
389
390 struct uci_history
391 {
392 struct uci_element e;
393 enum uci_command cmd;
394 char *section;
395 char *value;
396 };
397
398
399 /* linked list handling */
400 #ifndef offsetof
401 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
402 #endif
403
404 /**
405 * container_of - cast a member of a structure out to the containing structure
406 * @ptr: the pointer to the member.
407 * @type: the type of the container struct this is embedded in.
408 * @member: the name of the member within the struct.
409 */
410 #define container_of(ptr, type, member) \
411 ((type *) ((char *)ptr - offsetof(type,member)))
412
413
414 /**
415 * uci_list_entry: casts an uci_list pointer to the containing struct.
416 * @_type: config, section or option
417 * @_ptr: pointer to the uci_list struct
418 */
419 #define list_to_element(ptr) \
420 container_of(ptr, struct uci_element, list)
421
422 /**
423 * uci_foreach_entry: loop through a list of uci elements
424 * @_list: pointer to the uci_list struct
425 * @_ptr: iteration variable, struct uci_element
426 *
427 * use like a for loop, e.g:
428 * uci_foreach(&list, p) {
429 * ...
430 * }
431 */
432 #define uci_foreach_element(_list, _ptr) \
433 for(_ptr = list_to_element((_list)->next); \
434 &_ptr->list != (_list); \
435 _ptr = list_to_element(_ptr->list.next))
436
437 /**
438 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
439 * @_list: pointer to the uci_list struct
440 * @_tmp: temporary variable, struct uci_element *
441 * @_ptr: iteration variable, struct uci_element *
442 *
443 * use like a for loop, e.g:
444 * uci_foreach(&list, p) {
445 * ...
446 * }
447 */
448 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
449 for(_ptr = list_to_element((_list)->next), \
450 _tmp = list_to_element(_ptr->list.next); \
451 &_ptr->list != (_list); \
452 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
453
454 /**
455 * uci_list_empty: returns true if a list is empty
456 * @list: list head
457 */
458 #define uci_list_empty(list) ((list)->next == (list))
459
460 /* wrappers for dynamic type handling */
461 #define uci_type_backend UCI_TYPE_BACKEND
462 #define uci_type_history UCI_TYPE_HISTORY
463 #define uci_type_package UCI_TYPE_PACKAGE
464 #define uci_type_section UCI_TYPE_SECTION
465 #define uci_type_option UCI_TYPE_OPTION
466
467 /* element typecasting */
468 #ifdef UCI_DEBUG_TYPECAST
469 static const char *uci_typestr[] = {
470 [uci_type_backend] = "backend",
471 [uci_type_history] = "history",
472 [uci_type_package] = "package",
473 [uci_type_section] = "section",
474 [uci_type_option] = "option",
475 };
476
477 static void uci_typecast_error(int from, int to)
478 {
479 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
480 }
481
482 #define BUILD_CAST(_type) \
483 static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
484 { \
485 if (e->type != uci_type_ ## _type) { \
486 uci_typecast_error(e->type, uci_type_ ## _type); \
487 } \
488 return (struct uci_ ## _type *) e; \
489 }
490
491 BUILD_CAST(backend)
492 BUILD_CAST(history)
493 BUILD_CAST(package)
494 BUILD_CAST(section)
495 BUILD_CAST(option)
496
497 #else
498 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
499 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
500 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
501 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
502 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
503 #endif
504
505 /**
506 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
507 * @ctx: uci context
508 * @type: {package,section,option}
509 * @name: string containing the name of the element
510 * @datasize: additional buffer size to reserve at the end of the struct
511 */
512 #define uci_alloc_element(ctx, type, name, datasize) \
513 uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
514
515 #define uci_dataptr(ptr) \
516 (((char *) ptr) + sizeof(*ptr))
517
518 #endif