more cleanup
[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_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_import: Import uci config data from a stream
88 * @ctx: uci context
89 * @stream: file stream to import from
90 * @name: (optional) assume the config has the given name
91 * @package: (optional) store the last parsed config package in this variable
92 * @single: ignore the 'package' keyword and parse everything into a single package
93 *
94 * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
95 * if 'package' points to a non-null struct pointer, enable history tracking and merge
96 */
97 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
98
99 /**
100 * uci_export: Export one or all uci config packages
101 * @ctx: uci context
102 * @stream: output stream
103 * @package: (optional) uci config package to export
104 * @header: include the package header
105 */
106 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
107
108 /**
109 * uci_load: Parse an uci config file and store it in the uci context
110 *
111 * @ctx: uci context
112 * @name: name of the config file (relative to the config directory)
113 * @package: store the loaded config package in this variable
114 */
115 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
116
117 /**
118 * uci_unload: Unload a config file from the uci context
119 *
120 * @ctx: uci context
121 * @package: pointer to the uci_package struct
122 */
123 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
124
125 /**
126 * uci_lookup_ptr: Split an uci tuple string and look up an element tree
127 * @ctx: uci context
128 * @ptr: lookup result struct
129 * @str: uci tuple string to look up
130 * @extended: allow extended syntax lookup
131 *
132 * if extended is set to true, uci_lookup_ptr supports the following
133 * extended syntax:
134 *
135 * Examples:
136 * network.@interface[0].ifname ('ifname' option of the first interface section)
137 * network.@interface[-1] (last interface section)
138 * Note: uci_lookup_ext will automatically load a config package if necessary
139 */
140 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
141
142 /**
143 * uci_add_section: Add an unnamed section
144 * @ctx: uci context
145 * @p: package to add the section to
146 * @type: section type
147 * @res: pointer to store a reference to the new section in
148 */
149 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
150
151 /**
152 * uci_set_element_value: Replace an element's value with a new one
153 * @ctx: uci context
154 * @element: pointer to an uci_element struct pointer
155 * @value: new value
156 *
157 * Only valid for uci_option and uci_section. Will replace the type string
158 * when used with an uci_section
159 */
160 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, const char *value);
161
162 /**
163 * uci_set: Set an element's value; create the element if necessary
164 * @ctx: uci context
165 * @package: package name
166 * @section: section name
167 * @option: option name
168 * @value: value (option) or type (section)
169 * @result: store the updated element in this variable (optional)
170 */
171 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);
172
173 /**
174 * uci_add_list: Append a string to an element list
175 * @ctx: uci context
176 * @ptr: uci pointer (with value)
177 *
178 * Note: if the given option already contains a string value,
179 * it will be converted to an 1-element-list before appending the next element
180 */
181 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
182
183 /**
184 * uci_rename: Rename an element
185 * @ctx: uci context
186 * @ptr: uci pointer (with value)
187 */
188 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
189
190 /**
191 * uci_delete: Delete a section or option
192 * @ctx: uci context
193 * @ptr: uci pointer
194 */
195 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
196
197 /**
198 * uci_save: save change history for a package
199 * @ctx: uci context
200 * @p: uci_package struct
201 */
202 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
203
204 /**
205 * uci_commit: commit changes to a package
206 * @ctx: uci context
207 * @p: uci_package struct pointer
208 * @overwrite: overwrite existing config data and flush history
209 *
210 * committing may reload the whole uci_package data,
211 * the supplied pointer is updated accordingly
212 */
213 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
214
215 /**
216 * uci_list_configs: List available uci config files
217 * @ctx: uci context
218 *
219 * caller is responsible for freeing the allocated memory behind list
220 */
221 extern int uci_list_configs(struct uci_context *ctx, char ***list);
222
223 /**
224 * uci_set_savedir: override the default history save directory
225 * @ctx: uci context
226 * @dir: directory name
227 */
228 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
229
230 /**
231 * uci_set_savedir: override the default config storage directory
232 * @ctx: uci context
233 * @dir: directory name
234 */
235 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
236
237 /**
238 * uci_add_history_path: add a directory to the search path for change history files
239 * @ctx: uci context
240 * @dir: directory name
241 *
242 * This function allows you to add directories, which contain 'overlays'
243 * for the active config, that will never be committed.
244 */
245 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
246
247 /**
248 * uci_revert: revert all changes to a config item
249 * @ctx: uci context
250 * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
251 * @section: section name (optional)
252 * @option option name (optional)
253 */
254 extern int uci_revert(struct uci_context *ctx, struct uci_package **p, const char *section, const char *option);
255
256 /**
257 * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
258 * @ctx: uci context
259 * @stream: input stream
260 * @str: pointer to the current line (use NULL for parsing the next line)
261 * @result: pointer for the result
262 */
263 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
264
265 /**
266 * uci_set_backend: change the default backend
267 * @ctx: uci context
268 * @name: name of the backend
269 *
270 * The default backend is "file", which uses /etc/config for config storage
271 */
272 extern int uci_set_backend(struct uci_context *ctx, const char *name);
273
274 /**
275 * uci_validate_text: validate a value string for uci options
276 * @str: value
277 *
278 * this function checks whether a given string is acceptable as value
279 * for uci options
280 */
281 extern bool uci_validate_text(const char *str);
282
283 /* UCI data structures */
284 enum uci_type {
285 UCI_TYPE_UNSPEC = 0,
286 UCI_TYPE_HISTORY = 1,
287 UCI_TYPE_PACKAGE = 2,
288 UCI_TYPE_SECTION = 3,
289 UCI_TYPE_OPTION = 4,
290 UCI_TYPE_PATH = 5,
291 UCI_TYPE_BACKEND = 6,
292 UCI_TYPE_ITEM = 7,
293 };
294
295 enum uci_option_type {
296 UCI_TYPE_STRING = 0,
297 UCI_TYPE_LIST = 1,
298 };
299
300 enum uci_flags {
301 UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
302 UCI_FLAG_PERROR = (1 << 1), /* print parser error messages */
303 UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
304 UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
305 };
306
307 struct uci_element
308 {
309 struct uci_list list;
310 enum uci_type type;
311 char *name;
312 };
313
314 struct uci_backend
315 {
316 struct uci_element e;
317 char **(*list_configs)(struct uci_context *ctx);
318 struct uci_package *(*load)(struct uci_context *ctx, const char *name);
319 void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
320
321 /* private: */
322 const void *ptr;
323 void *priv;
324 };
325
326 struct uci_context
327 {
328 /* list of config packages */
329 struct uci_list root;
330
331 /* parser context, use for error handling only */
332 struct uci_parse_context *pctx;
333
334 /* backend for import and export */
335 struct uci_backend *backend;
336 struct uci_list backends;
337
338 /* uci runtime flags */
339 enum uci_flags flags;
340
341 char *confdir;
342 char *savedir;
343
344 /* search path for history files */
345 struct uci_list history_path;
346
347 /* private: */
348 int err;
349 const char *func;
350 jmp_buf trap;
351 bool internal, nested;
352 char *buf;
353 int bufsz;
354 };
355
356 struct uci_package
357 {
358 struct uci_element e;
359 struct uci_list sections;
360 struct uci_context *ctx;
361 bool has_history;
362 char *path;
363
364 /* private: */
365 struct uci_backend *backend;
366 void *priv;
367 int n_section;
368 struct uci_list history;
369 struct uci_list saved_history;
370 };
371
372 struct uci_section
373 {
374 struct uci_element e;
375 struct uci_list options;
376 struct uci_package *package;
377 bool anonymous;
378 char *type;
379 };
380
381 struct uci_option
382 {
383 struct uci_element e;
384 struct uci_section *section;
385 enum uci_option_type type;
386 union {
387 struct uci_list list;
388 char *string;
389 } v;
390 };
391
392 enum uci_command {
393 UCI_CMD_ADD,
394 UCI_CMD_REMOVE,
395 UCI_CMD_CHANGE,
396 UCI_CMD_RENAME,
397 UCI_CMD_LIST_ADD,
398 };
399
400 struct uci_history
401 {
402 struct uci_element e;
403 enum uci_command cmd;
404 char *section;
405 char *value;
406 };
407
408 struct uci_ptr
409 {
410 enum uci_type target;
411 enum {
412 UCI_LOOKUP_DONE = (1 << 0),
413 UCI_LOOKUP_COMPLETE = (1 << 1),
414 UCI_LOOKUP_EXTENDED = (1 << 2),
415 } flags;
416
417 struct uci_package *p;
418 struct uci_section *s;
419 struct uci_option *o;
420 struct uci_element *last;
421
422 const char *package;
423 const char *section;
424 const char *option;
425 const char *value;
426 };
427
428
429 /* linked list handling */
430 #ifndef offsetof
431 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
432 #endif
433
434 /**
435 * container_of - cast a member of a structure out to the containing structure
436 * @ptr: the pointer to the member.
437 * @type: the type of the container struct this is embedded in.
438 * @member: the name of the member within the struct.
439 */
440 #define container_of(ptr, type, member) \
441 ((type *) ((char *)ptr - offsetof(type,member)))
442
443
444 /**
445 * uci_list_entry: casts an uci_list pointer to the containing struct.
446 * @_type: config, section or option
447 * @_ptr: pointer to the uci_list struct
448 */
449 #define list_to_element(ptr) \
450 container_of(ptr, struct uci_element, list)
451
452 /**
453 * uci_foreach_entry: loop through a list of uci elements
454 * @_list: pointer to the uci_list struct
455 * @_ptr: iteration variable, struct uci_element
456 *
457 * use like a for loop, e.g:
458 * uci_foreach(&list, p) {
459 * ...
460 * }
461 */
462 #define uci_foreach_element(_list, _ptr) \
463 for(_ptr = list_to_element((_list)->next); \
464 &_ptr->list != (_list); \
465 _ptr = list_to_element(_ptr->list.next))
466
467 /**
468 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
469 * @_list: pointer to the uci_list struct
470 * @_tmp: temporary variable, struct uci_element *
471 * @_ptr: iteration variable, struct uci_element *
472 *
473 * use like a for loop, e.g:
474 * uci_foreach(&list, p) {
475 * ...
476 * }
477 */
478 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
479 for(_ptr = list_to_element((_list)->next), \
480 _tmp = list_to_element(_ptr->list.next); \
481 &_ptr->list != (_list); \
482 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
483
484 /**
485 * uci_list_empty: returns true if a list is empty
486 * @list: list head
487 */
488 #define uci_list_empty(list) ((list)->next == (list))
489
490 /* wrappers for dynamic type handling */
491 #define uci_type_backend UCI_TYPE_BACKEND
492 #define uci_type_history UCI_TYPE_HISTORY
493 #define uci_type_package UCI_TYPE_PACKAGE
494 #define uci_type_section UCI_TYPE_SECTION
495 #define uci_type_option UCI_TYPE_OPTION
496
497 /* element typecasting */
498 #ifdef UCI_DEBUG_TYPECAST
499 static const char *uci_typestr[] = {
500 [uci_type_backend] = "backend",
501 [uci_type_history] = "history",
502 [uci_type_package] = "package",
503 [uci_type_section] = "section",
504 [uci_type_option] = "option",
505 };
506
507 static void uci_typecast_error(int from, int to)
508 {
509 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
510 }
511
512 #define BUILD_CAST(_type) \
513 static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
514 { \
515 if (e->type != uci_type_ ## _type) { \
516 uci_typecast_error(e->type, uci_type_ ## _type); \
517 } \
518 return (struct uci_ ## _type *) e; \
519 }
520
521 BUILD_CAST(backend)
522 BUILD_CAST(history)
523 BUILD_CAST(package)
524 BUILD_CAST(section)
525 BUILD_CAST(option)
526
527 #else
528 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
529 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
530 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
531 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
532 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
533 #endif
534
535 /**
536 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
537 * @ctx: uci context
538 * @type: {package,section,option}
539 * @name: string containing the name of the element
540 * @datasize: additional buffer size to reserve at the end of the struct
541 */
542 #define uci_alloc_element(ctx, type, name, datasize) \
543 uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
544
545 #define uci_dataptr(ptr) \
546 (((char *) ptr) + sizeof(*ptr))
547
548 #endif