lua: add a return code for aborting iteration in uci_foreach
[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_plugin;
60 struct uci_hook_ops;
61 struct uci_element;
62 struct uci_package;
63 struct uci_section;
64 struct uci_option;
65 struct uci_history;
66 struct uci_context;
67 struct uci_backend;
68 struct uci_parse_context;
69
70
71 /**
72 * uci_alloc_context: Allocate a new uci context
73 */
74 extern struct uci_context *uci_alloc_context(void);
75
76 /**
77 * uci_free_context: Free the uci context including all of its data
78 */
79 extern void uci_free_context(struct uci_context *ctx);
80
81 /**
82 * uci_perror: Print the last uci error that occured
83 * @ctx: uci context
84 * @str: string to print before the error message
85 */
86 extern void uci_perror(struct uci_context *ctx, const char *str);
87
88 /**
89 * uci_geterror: Get an error string for the last uci error
90 * @ctx: uci context
91 * @dest: target pointer for the string
92 * @str: prefix for the error message
93 *
94 * Note: string must be freed by the caller
95 */
96 extern void uci_get_errorstr(struct uci_context *ctx, char **dest, 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_ptr: Split an uci tuple string and look up an element tree
139 * @ctx: uci context
140 * @ptr: lookup result struct
141 * @str: uci tuple string to look up
142 * @extended: allow extended syntax lookup
143 *
144 * if extended is set to true, uci_lookup_ptr supports the following
145 * extended syntax:
146 *
147 * Examples:
148 * network.@interface[0].ifname ('ifname' option of the first interface section)
149 * network.@interface[-1] (last interface section)
150 * Note: uci_lookup_ext will automatically load a config package if necessary
151 */
152 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
153
154 /**
155 * uci_add_section: Add an unnamed section
156 * @ctx: uci context
157 * @p: package to add the section to
158 * @type: section type
159 * @res: pointer to store a reference to the new section in
160 */
161 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
162
163 /**
164 * uci_set: Set an element's value; create the element if necessary
165 * @ctx: uci context
166 * @ptr: uci pointer
167 *
168 * The updated/created element is stored in ptr->last
169 */
170 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
171
172 /**
173 * uci_add_list: Append a string to an element list
174 * @ctx: uci context
175 * @ptr: uci pointer (with value)
176 *
177 * Note: if the given option already contains a string value,
178 * it will be converted to an 1-element-list before appending the next element
179 */
180 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
181
182 /**
183 * uci_reorder: Reposition a section
184 * @ctx: uci context
185 * @s: uci section to reposition
186 * @pos: new position in the section list
187 */
188 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
189
190 /**
191 * uci_rename: Rename an element
192 * @ctx: uci context
193 * @ptr: uci pointer (with value)
194 */
195 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
196
197 /**
198 * uci_delete: Delete a section or option
199 * @ctx: uci context
200 * @ptr: uci pointer
201 */
202 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
203
204 /**
205 * uci_save: save change history for a package
206 * @ctx: uci context
207 * @p: uci_package struct
208 */
209 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
210
211 /**
212 * uci_commit: commit changes to a package
213 * @ctx: uci context
214 * @p: uci_package struct pointer
215 * @overwrite: overwrite existing config data and flush history
216 *
217 * committing may reload the whole uci_package data,
218 * the supplied pointer is updated accordingly
219 */
220 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
221
222 /**
223 * uci_list_configs: List available uci config files
224 * @ctx: uci context
225 *
226 * caller is responsible for freeing the allocated memory behind list
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, const 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, const char *dir);
243
244 /**
245 * uci_add_history_path: add a directory to the search path for change history files
246 * @ctx: uci context
247 * @dir: directory name
248 *
249 * This function allows you to add directories, which contain 'overlays'
250 * for the active config, that will never be committed.
251 */
252 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
253
254 /**
255 * uci_revert: revert all changes to a config item
256 * @ctx: uci context
257 * @ptr: uci pointer
258 */
259 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
260
261 /**
262 * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
263 * @ctx: uci context
264 * @stream: input stream
265 * @str: pointer to the current line (use NULL for parsing the next line)
266 * @result: pointer for the result
267 */
268 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
269
270 /**
271 * uci_set_backend: change the default backend
272 * @ctx: uci context
273 * @name: name of the backend
274 *
275 * The default backend is "file", which uses /etc/config for config storage
276 */
277 extern int uci_set_backend(struct uci_context *ctx, const char *name);
278
279 /**
280 * uci_validate_text: validate a value string for uci options
281 * @str: value
282 *
283 * this function checks whether a given string is acceptable as value
284 * for uci options
285 */
286 extern bool uci_validate_text(const char *str);
287
288
289 /**
290 * uci_add_hook: add a uci hook
291 * @ctx: uci context
292 * @ops: uci hook ops
293 *
294 * NB: allocated and freed by the caller
295 */
296 extern int uci_add_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
297
298 /**
299 * uci_remove_hook: remove a uci hook
300 * @ctx: uci context
301 * @ops: uci hook ops
302 */
303 extern int uci_remove_hook(struct uci_context *ctx, const struct uci_hook_ops *ops);
304
305 /**
306 * uci_load_plugin: load an uci plugin
307 * @ctx: uci context
308 * @filename: path to the uci plugin
309 *
310 * NB: plugin will be unloaded automatically when the context is freed
311 */
312 int uci_load_plugin(struct uci_context *ctx, const char *filename);
313
314 /**
315 * uci_load_plugins: load all uci plugins from a directory
316 * @ctx: uci context
317 * @pattern: pattern of uci plugin files (optional)
318 *
319 * if pattern is NULL, then uci_load_plugins will call uci_load_plugin
320 * for uci_*.so in <prefix>/lib/
321 */
322 int uci_load_plugins(struct uci_context *ctx, const char *pattern);
323
324
325 /* UCI data structures */
326 enum uci_type {
327 UCI_TYPE_UNSPEC = 0,
328 UCI_TYPE_HISTORY = 1,
329 UCI_TYPE_PACKAGE = 2,
330 UCI_TYPE_SECTION = 3,
331 UCI_TYPE_OPTION = 4,
332 UCI_TYPE_PATH = 5,
333 UCI_TYPE_BACKEND = 6,
334 UCI_TYPE_ITEM = 7,
335 UCI_TYPE_HOOK = 8,
336 UCI_TYPE_PLUGIN = 9,
337 };
338
339 enum uci_option_type {
340 UCI_TYPE_STRING = 0,
341 UCI_TYPE_LIST = 1,
342 };
343
344 enum uci_flags {
345 UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
346 UCI_FLAG_PERROR = (1 << 1), /* print parser error messages */
347 UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
348 UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
349 };
350
351 struct uci_element
352 {
353 struct uci_list list;
354 enum uci_type type;
355 char *name;
356 };
357
358 struct uci_backend
359 {
360 struct uci_element e;
361 char **(*list_configs)(struct uci_context *ctx);
362 struct uci_package *(*load)(struct uci_context *ctx, const char *name);
363 void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
364
365 /* private: */
366 const void *ptr;
367 void *priv;
368 };
369
370 struct uci_context
371 {
372 /* list of config packages */
373 struct uci_list root;
374
375 /* parser context, use for error handling only */
376 struct uci_parse_context *pctx;
377
378 /* backend for import and export */
379 struct uci_backend *backend;
380 struct uci_list backends;
381
382 /* uci runtime flags */
383 enum uci_flags flags;
384
385 char *confdir;
386 char *savedir;
387
388 /* search path for history files */
389 struct uci_list history_path;
390
391 /* private: */
392 int err;
393 const char *func;
394 jmp_buf trap;
395 bool internal, nested;
396 char *buf;
397 int bufsz;
398
399 struct uci_list hooks;
400 struct uci_list plugins;
401 };
402
403 struct uci_package
404 {
405 struct uci_element e;
406 struct uci_list sections;
407 struct uci_context *ctx;
408 bool has_history;
409 char *path;
410
411 /* private: */
412 struct uci_backend *backend;
413 void *priv;
414 int n_section;
415 struct uci_list history;
416 struct uci_list saved_history;
417 };
418
419 struct uci_section
420 {
421 struct uci_element e;
422 struct uci_list options;
423 struct uci_package *package;
424 bool anonymous;
425 char *type;
426 };
427
428 struct uci_option
429 {
430 struct uci_element e;
431 struct uci_section *section;
432 enum uci_option_type type;
433 union {
434 struct uci_list list;
435 char *string;
436 } v;
437 };
438
439 enum uci_command {
440 UCI_CMD_ADD,
441 UCI_CMD_REMOVE,
442 UCI_CMD_CHANGE,
443 UCI_CMD_RENAME,
444 UCI_CMD_REORDER,
445 UCI_CMD_LIST_ADD,
446 };
447
448 struct uci_history
449 {
450 struct uci_element e;
451 enum uci_command cmd;
452 char *section;
453 char *value;
454 };
455
456 struct uci_ptr
457 {
458 enum uci_type target;
459 enum {
460 UCI_LOOKUP_DONE = (1 << 0),
461 UCI_LOOKUP_COMPLETE = (1 << 1),
462 UCI_LOOKUP_EXTENDED = (1 << 2),
463 } flags;
464
465 struct uci_package *p;
466 struct uci_section *s;
467 struct uci_option *o;
468 struct uci_element *last;
469
470 const char *package;
471 const char *section;
472 const char *option;
473 const char *value;
474 };
475
476 struct uci_hook_ops
477 {
478 void (*load)(const struct uci_hook_ops *ops, struct uci_package *p);
479 void (*set)(const struct uci_hook_ops *ops, struct uci_package *p, struct uci_history *e);
480 };
481
482 struct uci_hook
483 {
484 struct uci_element e;
485 const struct uci_hook_ops *ops;
486 };
487
488 struct uci_plugin_ops
489 {
490 int (*attach)(struct uci_context *ctx);
491 void (*detach)(struct uci_context *ctx);
492 };
493
494 struct uci_plugin
495 {
496 struct uci_element e;
497 const struct uci_plugin_ops *ops;
498 void *dlh;
499 };
500
501
502 /* linked list handling */
503 #ifndef offsetof
504 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
505 #endif
506
507 /**
508 * container_of - cast a member of a structure out to the containing structure
509 * @ptr: the pointer to the member.
510 * @type: the type of the container struct this is embedded in.
511 * @member: the name of the member within the struct.
512 */
513 #ifndef container_of
514 #define container_of(ptr, type, member) \
515 ((type *) ((char *)ptr - offsetof(type,member)))
516 #endif
517
518
519 /**
520 * uci_list_entry: casts an uci_list pointer to the containing struct.
521 * @_type: config, section or option
522 * @_ptr: pointer to the uci_list struct
523 */
524 #define list_to_element(ptr) \
525 container_of(ptr, struct uci_element, list)
526
527 /**
528 * uci_foreach_entry: loop through a list of uci elements
529 * @_list: pointer to the uci_list struct
530 * @_ptr: iteration variable, struct uci_element
531 *
532 * use like a for loop, e.g:
533 * uci_foreach(&list, p) {
534 * ...
535 * }
536 */
537 #define uci_foreach_element(_list, _ptr) \
538 for(_ptr = list_to_element((_list)->next); \
539 &_ptr->list != (_list); \
540 _ptr = list_to_element(_ptr->list.next))
541
542 /**
543 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
544 * @_list: pointer to the uci_list struct
545 * @_tmp: temporary variable, struct uci_element *
546 * @_ptr: iteration variable, struct uci_element *
547 *
548 * use like a for loop, e.g:
549 * uci_foreach(&list, p) {
550 * ...
551 * }
552 */
553 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
554 for(_ptr = list_to_element((_list)->next), \
555 _tmp = list_to_element(_ptr->list.next); \
556 &_ptr->list != (_list); \
557 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
558
559 /**
560 * uci_list_empty: returns true if a list is empty
561 * @list: list head
562 */
563 #define uci_list_empty(list) ((list)->next == (list))
564
565 /* wrappers for dynamic type handling */
566 #define uci_type_backend UCI_TYPE_BACKEND
567 #define uci_type_history UCI_TYPE_HISTORY
568 #define uci_type_package UCI_TYPE_PACKAGE
569 #define uci_type_section UCI_TYPE_SECTION
570 #define uci_type_option UCI_TYPE_OPTION
571 #define uci_type_hook UCI_TYPE_HOOK
572 #define uci_type_plugin UCI_TYPE_PLUGIN
573
574 /* element typecasting */
575 #ifdef UCI_DEBUG_TYPECAST
576 static const char *uci_typestr[] = {
577 [uci_type_backend] = "backend",
578 [uci_type_history] = "history",
579 [uci_type_package] = "package",
580 [uci_type_section] = "section",
581 [uci_type_option] = "option",
582 [uci_type_hook] = "hook",
583 [uci_type_plugin] = "plugin",
584 };
585
586 static void uci_typecast_error(int from, int to)
587 {
588 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
589 }
590
591 #define BUILD_CAST(_type) \
592 static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
593 { \
594 if (e->type != uci_type_ ## _type) { \
595 uci_typecast_error(e->type, uci_type_ ## _type); \
596 } \
597 return (struct uci_ ## _type *) e; \
598 }
599
600 BUILD_CAST(backend)
601 BUILD_CAST(history)
602 BUILD_CAST(package)
603 BUILD_CAST(section)
604 BUILD_CAST(option)
605 BUILD_CAST(hook)
606 BUILD_CAST(plugin)
607
608 #else
609 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
610 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
611 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
612 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
613 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
614 #define uci_to_hook(ptr) container_of(ptr, struct uci_hook, e)
615 #define uci_to_plugin(ptr) container_of(ptr, struct uci_plugin, e)
616 #endif
617
618 /**
619 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
620 * @ctx: uci context
621 * @type: {package,section,option}
622 * @name: string containing the name of the element
623 * @datasize: additional buffer size to reserve at the end of the struct
624 */
625 #define uci_alloc_element(ctx, type, name, datasize) \
626 uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
627
628 #define uci_dataptr(ptr) \
629 (((char *) ptr) + sizeof(*ptr))
630
631 #endif