file.c: lift the 4096 bytes line length limit.
[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 Lesser General Public License for more details.
13 */
14
15 #ifndef __LIBUCI_H
16 #define __LIBUCI_H
17
18 #ifdef __cplusplus
19 extern "C" {
20 #endif
21
22 #include "uci_config.h"
23
24 /*
25 * you can use these defines to enable debugging behavior for
26 * apps compiled against libuci:
27 *
28 * #define UCI_DEBUG_TYPECAST:
29 * enable uci_element typecast checking at run time
30 *
31 */
32
33 #include <stdbool.h>
34 #include <setjmp.h>
35 #include <stdio.h>
36 #include <stdint.h>
37
38 #define UCI_CONFDIR "/etc/config"
39 #define UCI_SAVEDIR "/tmp/.uci"
40 #define UCI_DIRMODE 0700
41 #define UCI_FILEMODE 0600
42
43 enum
44 {
45 UCI_OK = 0,
46 UCI_ERR_MEM,
47 UCI_ERR_INVAL,
48 UCI_ERR_NOTFOUND,
49 UCI_ERR_IO,
50 UCI_ERR_PARSE,
51 UCI_ERR_DUPLICATE,
52 UCI_ERR_UNKNOWN,
53 UCI_ERR_LAST
54 };
55
56 struct uci_list;
57 struct uci_list
58 {
59 struct uci_list *next;
60 struct uci_list *prev;
61 };
62
63 struct uci_ptr;
64 struct uci_element;
65 struct uci_package;
66 struct uci_section;
67 struct uci_option;
68 struct uci_delta;
69 struct uci_context;
70 struct uci_backend;
71 struct uci_parse_option;
72 struct uci_parse_context;
73
74
75 /**
76 * uci_alloc_context: Allocate a new uci context
77 */
78 extern struct uci_context *uci_alloc_context(void);
79
80 /**
81 * uci_free_context: Free the uci context including all of its data
82 */
83 extern void uci_free_context(struct uci_context *ctx);
84
85 /**
86 * uci_perror: Print the last uci error that occured
87 * @ctx: uci context
88 * @str: string to print before the error message
89 */
90 extern void uci_perror(struct uci_context *ctx, const char *str);
91
92 /**
93 * uci_geterror: Get an error string for the last uci error
94 * @ctx: uci context
95 * @dest: target pointer for the string
96 * @str: prefix for the error message
97 *
98 * Note: string must be freed by the caller
99 */
100 extern void uci_get_errorstr(struct uci_context *ctx, char **dest, const char *str);
101
102 /**
103 * uci_import: Import uci config data from a stream
104 * @ctx: uci context
105 * @stream: file stream to import from
106 * @name: (optional) assume the config has the given name
107 * @package: (optional) store the last parsed config package in this variable
108 * @single: ignore the 'package' keyword and parse everything into a single package
109 *
110 * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
111 * if 'package' points to a non-null struct pointer, enable delta tracking and merge
112 */
113 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single);
114
115 /**
116 * uci_export: Export one or all uci config packages
117 * @ctx: uci context
118 * @stream: output stream
119 * @package: (optional) uci config package to export
120 * @header: include the package header
121 */
122 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header);
123
124 /**
125 * uci_load: Parse an uci config file and store it in the uci context
126 *
127 * @ctx: uci context
128 * @name: name of the config file (relative to the config directory)
129 * @package: store the loaded config package in this variable
130 */
131 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
132
133 /**
134 * uci_unload: Unload a config file from the uci context
135 *
136 * @ctx: uci context
137 * @package: pointer to the uci_package struct
138 */
139 extern int uci_unload(struct uci_context *ctx, struct uci_package *p);
140
141 /**
142 * uci_lookup_ptr: Split an uci tuple string and look up an element tree
143 * @ctx: uci context
144 * @ptr: lookup result struct
145 * @str: uci tuple string to look up
146 * @extended: allow extended syntax lookup
147 *
148 * if extended is set to true, uci_lookup_ptr supports the following
149 * extended syntax:
150 *
151 * Examples:
152 * network.@interface[0].ifname ('ifname' option of the first interface section)
153 * network.@interface[-1] (last interface section)
154 * Note: uci_lookup_ptr will automatically load a config package if necessary
155 * @str must not be constant, as it will be modified and used for the strings inside @ptr,
156 * thus it must also be available as long as @ptr is in use.
157 *
158 * This function returns UCI_ERR_NOTFOUND if the package specified in the tuple
159 * string cannot be found. Otherwise it will return UCI_OK.
160 *
161 * Note that failures in looking up other parts, if they are also specfied,
162 * including section and option, will also have a return value UCI_OK but with
163 * ptr->flags * UCI_LOOKUP_COMPLETE not set.
164 */
165 extern int uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended);
166
167 /**
168 * uci_add_section: Add an unnamed section
169 * @ctx: uci context
170 * @p: package to add the section to
171 * @type: section type
172 * @res: pointer to store a reference to the new section in
173 */
174 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
175
176 /**
177 * uci_set: Set an element's value; create the element if necessary
178 * @ctx: uci context
179 * @ptr: uci pointer
180 *
181 * The updated/created element is stored in ptr->last
182 */
183 extern int uci_set(struct uci_context *ctx, struct uci_ptr *ptr);
184
185 /**
186 * uci_add_list: Append a string to an element list
187 * @ctx: uci context
188 * @ptr: uci pointer (with value)
189 *
190 * Note: if the given option already contains a string value,
191 * it will be converted to an 1-element-list before appending the next element
192 */
193 extern int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr);
194
195 /**
196 * uci_del_list: Remove a string from an element list
197 * @ctx: uci context
198 * @ptr: uci pointer (with value)
199 *
200 */
201 extern int uci_del_list(struct uci_context *ctx, struct uci_ptr *ptr);
202
203 /**
204 * uci_reorder: Reposition a section
205 * @ctx: uci context
206 * @s: uci section to reposition
207 * @pos: new position in the section list
208 */
209 extern int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos);
210
211 /**
212 * uci_rename: Rename an element
213 * @ctx: uci context
214 * @ptr: uci pointer (with value)
215 */
216 extern int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr);
217
218 /**
219 * uci_delete: Delete a section or option
220 * @ctx: uci context
221 * @ptr: uci pointer
222 */
223 extern int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr);
224
225 /**
226 * uci_save: save change delta for a package
227 * @ctx: uci context
228 * @p: uci_package struct
229 */
230 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
231
232 /**
233 * uci_commit: commit changes to a package
234 * @ctx: uci context
235 * @p: uci_package struct pointer
236 * @overwrite: overwrite existing config data and flush delta
237 *
238 * committing may reload the whole uci_package data,
239 * the supplied pointer is updated accordingly
240 */
241 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
242
243 /**
244 * uci_list_configs: List available uci config files
245 * @ctx: uci context
246 *
247 * caller is responsible for freeing the allocated memory behind list
248 */
249 extern int uci_list_configs(struct uci_context *ctx, char ***list);
250
251 /**
252 * uci_set_savedir: override the default delta save directory
253 * @ctx: uci context
254 * @dir: directory name
255 *
256 * This will also try adding the specified dir to the end of delta pathes.
257 */
258 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
259
260 /**
261 * uci_set_savedir: override the default config storage directory
262 * @ctx: uci context
263 * @dir: directory name
264 */
265 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
266
267 /**
268 * uci_add_delta_path: add a directory to the search path for change delta files
269 * @ctx: uci context
270 * @dir: directory name
271 *
272 * This function allows you to add directories, which contain 'overlays'
273 * for the active config, that will never be committed.
274 *
275 * Adding a duplicate directory will cause UCI_ERR_DUPLICATE be returned.
276 */
277 extern int uci_add_delta_path(struct uci_context *ctx, const char *dir);
278
279 /**
280 * uci_revert: revert all changes to a config item
281 * @ctx: uci context
282 * @ptr: uci pointer
283 */
284 extern int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr);
285
286 /**
287 * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
288 * @ctx: uci context
289 * @stream: input stream
290 * @str: pointer to the current line (use NULL for parsing the next line)
291 * @result: pointer for the result
292 */
293 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
294
295 /**
296 * uci_set_backend: change the default backend
297 * @ctx: uci context
298 * @name: name of the backend
299 *
300 * The default backend is "file", which uses /etc/config for config storage
301 */
302 extern int uci_set_backend(struct uci_context *ctx, const char *name);
303
304 /**
305 * uci_validate_text: validate a value string for uci options
306 * @str: value
307 *
308 * this function checks whether a given string is acceptable as value
309 * for uci options
310 */
311 extern bool uci_validate_text(const char *str);
312
313 /**
314 * uci_parse_ptr: parse a uci string into a uci_ptr
315 * @ctx: uci context
316 * @ptr: target data structure
317 * @str: string to parse
318 *
319 * str is modified by this function
320 */
321 int uci_parse_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str);
322
323 /**
324 * uci_lookup_next: lookup a child element
325 * @ctx: uci context
326 * @e: target element pointer
327 * @list: list of elements
328 * @name: name of the child element
329 *
330 * if parent is NULL, the function looks up the package with the given name
331 */
332 int uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name);
333
334 /**
335 * uci_parse_section: look up a set of options
336 * @s: uci section
337 * @opts: list of options to look up
338 * @n_opts: number of options to look up
339 * @tb: array of pointers to found options
340 */
341 void uci_parse_section(struct uci_section *s, const struct uci_parse_option *opts,
342 int n_opts, struct uci_option **tb);
343
344 /**
345 * uci_hash_options: build a hash over a list of options
346 * @tb: list of option pointers
347 * @n_opts: number of options
348 */
349 uint32_t uci_hash_options(struct uci_option **tb, int n_opts);
350
351
352 /* UCI data structures */
353 enum uci_type {
354 UCI_TYPE_UNSPEC = 0,
355 UCI_TYPE_DELTA = 1,
356 UCI_TYPE_PACKAGE = 2,
357 UCI_TYPE_SECTION = 3,
358 UCI_TYPE_OPTION = 4,
359 UCI_TYPE_PATH = 5,
360 UCI_TYPE_BACKEND = 6,
361 UCI_TYPE_ITEM = 7,
362 UCI_TYPE_HOOK = 8,
363 };
364
365 enum uci_option_type {
366 UCI_TYPE_STRING = 0,
367 UCI_TYPE_LIST = 1,
368 };
369
370 enum uci_flags {
371 UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
372 UCI_FLAG_PERROR = (1 << 1), /* print parser error messages */
373 UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
374 UCI_FLAG_SAVED_DELTA = (1 << 3), /* store the saved delta in memory as well */
375 };
376
377 struct uci_element
378 {
379 struct uci_list list;
380 enum uci_type type;
381 char *name;
382 };
383
384 struct uci_backend
385 {
386 struct uci_element e;
387 char **(*list_configs)(struct uci_context *ctx);
388 struct uci_package *(*load)(struct uci_context *ctx, const char *name);
389 void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
390
391 /* private: */
392 const void *ptr;
393 void *priv;
394 };
395
396 struct uci_context
397 {
398 /* list of config packages */
399 struct uci_list root;
400
401 /* parser context, use for error handling only */
402 struct uci_parse_context *pctx;
403
404 /* backend for import and export */
405 struct uci_backend *backend;
406 struct uci_list backends;
407
408 /* uci runtime flags */
409 enum uci_flags flags;
410
411 char *confdir;
412 char *savedir;
413
414 /* search path for delta files */
415 struct uci_list delta_path;
416
417 /* private: */
418 int err;
419 const char *func;
420 jmp_buf trap;
421 bool internal, nested;
422 char *buf;
423 int bufsz;
424 };
425
426 struct uci_package
427 {
428 struct uci_element e;
429 struct uci_list sections;
430 struct uci_context *ctx;
431 bool has_delta;
432 char *path;
433
434 /* private: */
435 struct uci_backend *backend;
436 void *priv;
437 int n_section;
438 struct uci_list delta;
439 struct uci_list saved_delta;
440 };
441
442 struct uci_section
443 {
444 struct uci_element e;
445 struct uci_list options;
446 struct uci_package *package;
447 bool anonymous;
448 char *type;
449 };
450
451 struct uci_option
452 {
453 struct uci_element e;
454 struct uci_section *section;
455 enum uci_option_type type;
456 union {
457 struct uci_list list;
458 char *string;
459 } v;
460 };
461
462 /*
463 * UCI_CMD_ADD is used for anonymous sections or list values
464 */
465 enum uci_command {
466 UCI_CMD_ADD,
467 UCI_CMD_REMOVE,
468 UCI_CMD_CHANGE,
469 UCI_CMD_RENAME,
470 UCI_CMD_REORDER,
471 UCI_CMD_LIST_ADD,
472 UCI_CMD_LIST_DEL,
473 __UCI_CMD_MAX,
474 __UCI_CMD_LAST = __UCI_CMD_MAX - 1
475 };
476 extern char const uci_command_char[];
477
478 struct uci_delta
479 {
480 struct uci_element e;
481 enum uci_command cmd;
482 char *section;
483 char *value;
484 };
485
486 struct uci_ptr
487 {
488 enum uci_type target;
489 enum {
490 UCI_LOOKUP_DONE = (1 << 0),
491 UCI_LOOKUP_COMPLETE = (1 << 1),
492 UCI_LOOKUP_EXTENDED = (1 << 2),
493 } flags;
494
495 struct uci_package *p;
496 struct uci_section *s;
497 struct uci_option *o;
498 struct uci_element *last;
499
500 const char *package;
501 const char *section;
502 const char *option;
503 const char *value;
504 };
505
506 struct uci_parse_option {
507 const char *name;
508 enum uci_option_type type;
509 };
510
511
512 /* linked list handling */
513 #ifndef offsetof
514 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
515 #endif
516
517 /**
518 * container_of - cast a member of a structure out to the containing structure
519 * @ptr: the pointer to the member.
520 * @type: the type of the container struct this is embedded in.
521 * @member: the name of the member within the struct.
522 */
523 #ifndef container_of
524 #define container_of(ptr, type, member) \
525 ((type *) ((char *)ptr - offsetof(type,member)))
526 #endif
527
528
529 /**
530 * uci_list_entry: casts an uci_list pointer to the containing struct.
531 * @_type: config, section or option
532 * @_ptr: pointer to the uci_list struct
533 */
534 #define list_to_element(ptr) \
535 container_of(ptr, struct uci_element, list)
536
537 /**
538 * uci_foreach_entry: loop through a list of uci elements
539 * @_list: pointer to the uci_list struct
540 * @_ptr: iteration variable, struct uci_element
541 *
542 * use like a for loop, e.g:
543 * uci_foreach(&list, p) {
544 * ...
545 * }
546 */
547 #define uci_foreach_element(_list, _ptr) \
548 for(_ptr = list_to_element((_list)->next); \
549 &_ptr->list != (_list); \
550 _ptr = list_to_element(_ptr->list.next))
551
552 /**
553 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
554 * @_list: pointer to the uci_list struct
555 * @_tmp: temporary variable, struct uci_element *
556 * @_ptr: iteration variable, struct uci_element *
557 *
558 * use like a for loop, e.g:
559 * uci_foreach(&list, p) {
560 * ...
561 * }
562 */
563 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
564 for(_ptr = list_to_element((_list)->next), \
565 _tmp = list_to_element(_ptr->list.next); \
566 &_ptr->list != (_list); \
567 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
568
569 /**
570 * uci_list_empty: returns true if a list is empty
571 * @list: list head
572 */
573 #define uci_list_empty(list) ((list)->next == (list))
574
575 /* wrappers for dynamic type handling */
576 #define uci_type_backend UCI_TYPE_BACKEND
577 #define uci_type_delta UCI_TYPE_DELTA
578 #define uci_type_package UCI_TYPE_PACKAGE
579 #define uci_type_section UCI_TYPE_SECTION
580 #define uci_type_option UCI_TYPE_OPTION
581
582 /* element typecasting */
583 #ifdef UCI_DEBUG_TYPECAST
584 static const char *uci_typestr[] = {
585 [uci_type_backend] = "backend",
586 [uci_type_delta] = "delta",
587 [uci_type_package] = "package",
588 [uci_type_section] = "section",
589 [uci_type_option] = "option",
590 };
591
592 static void uci_typecast_error(int from, int to)
593 {
594 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
595 }
596
597 #define BUILD_CAST(_type) \
598 static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
599 { \
600 if (e->type != uci_type_ ## _type) { \
601 uci_typecast_error(e->type, uci_type_ ## _type); \
602 } \
603 return (struct uci_ ## _type *) e; \
604 }
605
606 BUILD_CAST(backend)
607 BUILD_CAST(delta)
608 BUILD_CAST(package)
609 BUILD_CAST(section)
610 BUILD_CAST(option)
611
612 #else
613 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
614 #define uci_to_delta(ptr) container_of(ptr, struct uci_delta, e)
615 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
616 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
617 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
618 #endif
619
620 /**
621 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
622 * @ctx: uci context
623 * @type: {package,section,option}
624 * @name: string containing the name of the element
625 * @datasize: additional buffer size to reserve at the end of the struct
626 */
627 #define uci_alloc_element(ctx, type, name, datasize) \
628 uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
629
630 #define uci_dataptr(ptr) \
631 (((char *) ptr) + sizeof(*ptr))
632
633 /**
634 * uci_lookup_package: look up a package
635 * @ctx: uci context
636 * @name: name of the package
637 */
638 static inline struct uci_package *
639 uci_lookup_package(struct uci_context *ctx, const char *name)
640 {
641 struct uci_element *e = NULL;
642 if (uci_lookup_next(ctx, &e, &ctx->root, name) == 0)
643 return uci_to_package(e);
644 else
645 return NULL;
646 }
647
648 /**
649 * uci_lookup_section: look up a section
650 * @ctx: uci context
651 * @p: package that the section belongs to
652 * @name: name of the section
653 */
654 static inline struct uci_section *
655 uci_lookup_section(struct uci_context *ctx, struct uci_package *p, const char *name)
656 {
657 struct uci_element *e = NULL;
658 if (uci_lookup_next(ctx, &e, &p->sections, name) == 0)
659 return uci_to_section(e);
660 else
661 return NULL;
662 }
663
664 /**
665 * uci_lookup_option: look up an option
666 * @ctx: uci context
667 * @section: section that the option belongs to
668 * @name: name of the option
669 */
670 static inline struct uci_option *
671 uci_lookup_option(struct uci_context *ctx, struct uci_section *s, const char *name)
672 {
673 struct uci_element *e = NULL;
674 if (uci_lookup_next(ctx, &e, &s->options, name) == 0)
675 return uci_to_option(e);
676 else
677 return NULL;
678 }
679
680 static inline const char *
681 uci_lookup_option_string(struct uci_context *ctx, struct uci_section *s, const char *name)
682 {
683 struct uci_option *o;
684
685 o = uci_lookup_option(ctx, s, name);
686 if (!o || o->type != UCI_TYPE_STRING)
687 return NULL;
688
689 return o->v.string;
690 }
691
692 #ifdef __cplusplus
693 }
694 #endif
695
696 #endif