allow the user of the library to override the confdir/searchdir
[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 /*
19 * you can use these defines to enable debugging behavior for
20 * apps compiled against libuci:
21 *
22 * #define UCI_DEBUG_TYPECAST:
23 * enable uci_element typecast checking at run time
24 *
25 */
26
27 #ifdef DEBUG_ALL
28 #define UCI_DEBUG
29 #define UCI_DEBUG_TYPECAST
30 #endif
31
32 #include <stdbool.h>
33 #include <setjmp.h>
34 #include <stdio.h>
35
36 #define UCI_CONFDIR "/etc/config"
37 #define UCI_SAVEDIR "/tmp/.uci"
38 #define UCI_FILEMODE 0600
39
40 enum
41 {
42 UCI_OK = 0,
43 UCI_ERR_MEM,
44 UCI_ERR_INVAL,
45 UCI_ERR_NOTFOUND,
46 UCI_ERR_IO,
47 UCI_ERR_PARSE,
48 UCI_ERR_DUPLICATE,
49 UCI_ERR_UNKNOWN,
50 UCI_ERR_LAST
51 };
52
53 struct uci_list;
54 struct uci_list
55 {
56 struct uci_list *next;
57 struct uci_list *prev;
58 };
59
60 struct uci_element;
61 struct uci_package;
62 struct uci_section;
63 struct uci_option;
64 struct uci_history;
65 struct uci_context;
66 struct uci_parse_context;
67
68
69 /**
70 * uci_parse_tuple: Parse an uci tuple
71 * @ctx: uci context
72 * @str: input string
73 * @package: output package pointer
74 * @section: output section pointer
75 * @option: output option pointer
76 * @value: output value pointer
77 *
78 * format: <package>[.<section>[.<option>]][=<value>]
79 */
80 extern int uci_parse_tuple(struct uci_context *ctx, char *str, char **package, char **section, char **option, char **value);
81
82 /**
83 * uci_alloc_context: Allocate a new uci context
84 */
85 extern struct uci_context *uci_alloc_context(void);
86
87 /**
88 * uci_free_context: Free the uci context including all of its data
89 */
90 extern void uci_free_context(struct uci_context *ctx);
91
92 /**
93 * uci_perror: Print the last uci error that occured
94 * @ctx: uci context
95 * @str: string to print before the error message
96 */
97 extern void uci_perror(struct uci_context *ctx, const char *str);
98
99 /**
100 * uci_import: Import uci config data from a stream
101 * @ctx: uci context
102 * @stream: file stream to import from
103 * @name: (optional) assume the config has the given name
104 * @package: (optional) store the last parsed config package in this variable
105 * @single: ignore the 'package' keyword and parse everything into a single package
106 *
107 * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
108 * if 'package' points to a non-null struct pointer, enable history tracking and merge
109 */
110 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
111
112 /**
113 * uci_export: Export one or all uci config packages
114 * @ctx: uci context
115 * @stream: output stream
116 * @package: (optional) uci config package to export
117 * @header: include the package header
118 */
119 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
120
121 /**
122 * uci_load: Parse an uci config file and store it in the uci context
123 *
124 * @ctx: uci context
125 * @name: name of the config file (relative to the config directory)
126 * @package: store the loaded config package in this variable
127 */
128 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
129
130 /**
131 * uci_unload: Unload a config file from the uci context
132 *
133 * @ctx: uci context
134 * @package: pointer to the uci_package struct
135 */
136 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
137
138 /**
139 * uci_cleanup: Clean up after an error
140 *
141 * @ctx: uci context
142 */
143 extern int uci_cleanup(struct uci_context *ctx);
144
145 /**
146 * uci_lookup: Look up an uci element
147 *
148 * @ctx: uci context
149 * @res: where to store the result
150 * @package: uci_package struct
151 * @section: config section (optional)
152 * @option: option to search for (optional)
153 *
154 * If section is omitted, then a pointer to the config package is returned
155 * If option is omitted, then a pointer to the config section is returned
156 */
157 extern int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *package, char *section, char *option);
158
159 /**
160 * uci_set_element_value: Replace an element's value with a new one
161 * @ctx: uci context
162 * @element: pointer to an uci_element struct pointer
163 * @value: new value
164 *
165 * Only valid for uci_option and uci_section. Will replace the type string
166 * when used with an uci_section
167 */
168 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value);
169
170 /**
171 * uci_set: Set an element's value; create the element if necessary
172 * @ctx: uci context
173 * @package: package name
174 * @section: section name
175 * @option: option name
176 * @value: value (option) or type (section)
177 */
178 extern int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value);
179
180 /**
181 * uci_rename: Rename an element
182 * @ctx: uci context
183 * @package: package name
184 * @section: section name
185 * @option: option name
186 * @name: new name
187 */
188 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
189
190 /**
191 * uci_delete_element: Delete a section or option
192 * @ctx: uci context
193 * @e: element (section or option)
194 */
195 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
196
197 /**
198 * uci_delete: Delete a section or option
199 * @ctx: uci context
200 * @p: uci package
201 * @section: section name
202 * @option: option name (optional)
203 */
204 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, char *section, char *option);
205
206 /**
207 * uci_save: save change history for a package
208 * @ctx: uci context
209 * @p: uci_package struct
210 */
211 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
212
213 /**
214 * uci_commit: commit changes to a package
215 * @ctx: uci context
216 * @p: uci_package struct pointer
217 * @overwrite: overwrite existing config data and flush history
218 *
219 * committing may reload the whole uci_package data,
220 * the supplied pointer is updated accordingly
221 */
222 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
223
224 /**
225 * uci_list_configs: List available uci config files
226 * @ctx: uci context
227 */
228 extern int uci_list_configs(struct uci_context *ctx, char ***list);
229
230 /**
231 * uci_set_savedir: override the default history save directory
232 * @ctx: uci context
233 * @dir: directory name
234 */
235 extern int uci_set_savedir(struct uci_context *ctx, char *dir);
236
237 /**
238 * uci_set_savedir: override the default config storage directory
239 * @ctx: uci context
240 * @dir: directory name
241 */
242 extern int uci_set_confdir(struct uci_context *ctx, char *dir);
243
244
245 /* UCI data structures */
246 enum uci_type {
247 UCI_TYPE_HISTORY = 0,
248 UCI_TYPE_PACKAGE = 1,
249 UCI_TYPE_SECTION = 2,
250 UCI_TYPE_OPTION = 3
251 };
252
253 enum uci_flags {
254 UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
255 UCI_FLAG_PERROR = (1 << 1), /* print parser error messages */
256 UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
257 };
258
259 struct uci_element
260 {
261 struct uci_list list;
262 enum uci_type type;
263 char *name;
264 };
265
266 struct uci_context
267 {
268 /* list of config packages */
269 struct uci_list root;
270
271 /* parser context, use for error handling only */
272 struct uci_parse_context *pctx;
273
274 /* uci runtime flags */
275 enum uci_flags flags;
276
277 char *confdir;
278 char *savedir;
279
280 /* private: */
281 int errno;
282 const char *func;
283 jmp_buf trap;
284 bool internal;
285 char *buf;
286 int bufsz;
287 };
288
289 struct uci_parse_context
290 {
291 /* error context */
292 const char *reason;
293 int line;
294 int byte;
295
296 /* private: */
297 struct uci_package *package;
298 struct uci_section *section;
299 bool merge;
300 FILE *file;
301 const char *name;
302 char *buf;
303 int bufsz;
304 };
305
306 struct uci_package
307 {
308 struct uci_element e;
309 struct uci_list sections;
310 struct uci_context *ctx;
311 bool confdir;
312 char *path;
313
314 /* private: */
315 int n_section;
316 struct uci_list history;
317 };
318
319 struct uci_section
320 {
321 struct uci_element e;
322 struct uci_list options;
323 struct uci_package *package;
324 bool anonymous;
325 char *type;
326 };
327
328 struct uci_option
329 {
330 struct uci_element e;
331 struct uci_section *section;
332 char *value;
333 };
334
335 enum uci_command {
336 UCI_CMD_ADD,
337 UCI_CMD_REMOVE,
338 UCI_CMD_CHANGE,
339 UCI_CMD_RENAME
340 };
341
342 struct uci_history
343 {
344 struct uci_element e;
345 enum uci_command cmd;
346 char *section;
347 char *value;
348 };
349
350 /* linked list handling */
351 #ifndef offsetof
352 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
353 #endif
354
355 /**
356 * container_of - cast a member of a structure out to the containing structure
357 * @ptr: the pointer to the member.
358 * @type: the type of the container struct this is embedded in.
359 * @member: the name of the member within the struct.
360 */
361 #define container_of(ptr, type, member) \
362 ((type *) ((char *)ptr - offsetof(type,member)))
363
364
365 /**
366 * uci_list_entry: casts an uci_list pointer to the containing struct.
367 * @_type: config, section or option
368 * @_ptr: pointer to the uci_list struct
369 */
370 #define element_to(type, ptr) \
371 container_of(ptr, struct uci_ ## type, e)
372
373 #define list_to_element(ptr) \
374 container_of(ptr, struct uci_element, list)
375
376 /**
377 * uci_foreach_entry: loop through a list of uci elements
378 * @_list: pointer to the uci_list struct
379 * @_ptr: iteration variable, struct uci_element
380 *
381 * use like a for loop, e.g:
382 * uci_foreach(&list, p) {
383 * ...
384 * }
385 */
386 #define uci_foreach_element(_list, _ptr) \
387 for(_ptr = list_to_element((_list)->next); \
388 &_ptr->list != (_list); \
389 _ptr = list_to_element(_ptr->list.next))
390
391 /**
392 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
393 * @_list: pointer to the uci_list struct
394 * @_tmp: temporary variable, struct uci_element *
395 * @_ptr: iteration variable, struct uci_element *
396 *
397 * use like a for loop, e.g:
398 * uci_foreach(&list, p) {
399 * ...
400 * }
401 */
402 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
403 for(_ptr = list_to_element((_list)->next), \
404 _tmp = list_to_element(_ptr->list.next); \
405 &_ptr->list != (_list); \
406 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
407
408 /**
409 * uci_list_empty: returns true if a list is empty
410 * @list: list head
411 */
412 #define uci_list_empty(list) ((list)->next == (list))
413
414 /* wrappers for dynamic type handling */
415 #define uci_type_history UCI_TYPE_HISTORY
416 #define uci_type_package UCI_TYPE_PACKAGE
417 #define uci_type_section UCI_TYPE_SECTION
418 #define uci_type_option UCI_TYPE_OPTION
419
420 /* element typecasting */
421 #ifdef UCI_DEBUG_TYPECAST
422 static const char *uci_typestr[] = {
423 [uci_type_history] = "history",
424 [uci_type_package] = "package",
425 [uci_type_section] = "section",
426 [uci_type_option] = "option",
427 };
428
429 static void uci_typecast_error(int from, int to)
430 {
431 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
432 }
433
434 #define BUILD_CAST(_type) \
435 static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
436 { \
437 if (e->type != uci_type_ ## _type) { \
438 uci_typecast_error(e->type, uci_type_ ## _type); \
439 } \
440 return (struct uci_ ## _type *) e; \
441 }
442
443 BUILD_CAST(history)
444 BUILD_CAST(package)
445 BUILD_CAST(section)
446 BUILD_CAST(option)
447
448 #else
449 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
450 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
451 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
452 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
453 #endif
454
455 /**
456 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
457 * @ctx: uci context
458 * @type: {package,section,option}
459 * @name: string containing the name of the element
460 * @datasize: additional buffer size to reserve at the end of the struct
461 */
462 #define uci_alloc_element(ctx, type, name, datasize) \
463 uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
464
465 #define uci_dataptr(ptr) \
466 (((char *) ptr) + sizeof(*ptr))
467
468 #endif