fix wrong buffer allocation
[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_lookup_ext: Extended lookup for an uci element
153 *
154 * @ctx: uci context
155 * @res: where to store the result
156 * @ptr: uci pointer tuple
157 *
158 * Looks up an element using the extended syntax, which is a superset of what
159 * uci_parse_tuple accepts. It can look up sections by an index with an optional
160 * type.
161 *
162 * Examples:
163 * network.@interface[0].ifname ('ifname' option of the first interface section)
164 * network.@interface[-1] (last interface section)
165 * Note: uci_lookup_ext will automatically load a config package if necessary
166 */
167 extern int uci_lookup_ext(struct uci_context *ctx, struct uci_element **res, char *ptr);
168
169 /**
170 * uci_add_section: Add an unnamed section
171 * @ctx: uci context
172 * @p: package to add the section to
173 * @type: section type
174 * @res: pointer to store a reference to the new section in
175 */
176 extern int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res);
177
178 /**
179 * uci_set_element_value: Replace an element's value with a new one
180 * @ctx: uci context
181 * @element: pointer to an uci_element struct pointer
182 * @value: new value
183 *
184 * Only valid for uci_option and uci_section. Will replace the type string
185 * when used with an uci_section
186 */
187 extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, const char *value);
188
189 /**
190 * uci_add_element_list: Append a string to a list option
191 * @ctx: uci context
192 * @option: pointer to the uci option element
193 * @value: string to append
194 */
195 extern int uci_add_element_list(struct uci_context *ctx, struct uci_option *o, const char *value);
196
197 /**
198 * uci_set: Set an element's value; create the element if necessary
199 * @ctx: uci context
200 * @package: package name
201 * @section: section name
202 * @option: option name
203 * @value: value (option) or type (section)
204 * @result: store the updated element in this variable (optional)
205 */
206 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);
207
208 /**
209 * uci_add_list: Append a string to an element list
210 * @ctx: uci context
211 * @package: package name
212 * @section: section name
213 * @option: option name
214 * @value: string value
215 * @result: store the updated element in this variable (optional)
216 *
217 * Note: if the given option already contains a string, convert it to an 1-element-list
218 * before appending the next element
219 */
220 extern int uci_add_list(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option, const char *value, struct uci_option **result);
221
222 /**
223 * uci_rename: Rename an element
224 * @ctx: uci context
225 * @package: package name
226 * @section: section name
227 * @option: option name
228 * @name: new name
229 */
230 extern int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name);
231
232 /**
233 * uci_delete_element: Delete a section or option
234 * @ctx: uci context
235 * @e: element (section or option)
236 */
237 extern int uci_delete_element(struct uci_context *ctx, struct uci_element *e);
238
239 /**
240 * uci_delete: Delete a section or option
241 * @ctx: uci context
242 * @p: uci package
243 * @section: section name
244 * @option: option name (optional)
245 */
246 extern int uci_delete(struct uci_context *ctx, struct uci_package *p, const char *section, const char *option);
247
248 /**
249 * uci_save: save change history for a package
250 * @ctx: uci context
251 * @p: uci_package struct
252 */
253 extern int uci_save(struct uci_context *ctx, struct uci_package *p);
254
255 /**
256 * uci_commit: commit changes to a package
257 * @ctx: uci context
258 * @p: uci_package struct pointer
259 * @overwrite: overwrite existing config data and flush history
260 *
261 * committing may reload the whole uci_package data,
262 * the supplied pointer is updated accordingly
263 */
264 extern int uci_commit(struct uci_context *ctx, struct uci_package **p, bool overwrite);
265
266 /**
267 * uci_list_configs: List available uci config files
268 * @ctx: uci context
269 *
270 * caller is responsible for freeing the allocated memory behind list
271 */
272 extern int uci_list_configs(struct uci_context *ctx, char ***list);
273
274 /**
275 * uci_set_savedir: override the default history save directory
276 * @ctx: uci context
277 * @dir: directory name
278 */
279 extern int uci_set_savedir(struct uci_context *ctx, const char *dir);
280
281 /**
282 * uci_set_savedir: override the default config storage directory
283 * @ctx: uci context
284 * @dir: directory name
285 */
286 extern int uci_set_confdir(struct uci_context *ctx, const char *dir);
287
288 /**
289 * uci_add_history_path: add a directory to the search path for change history files
290 * @ctx: uci context
291 * @dir: directory name
292 *
293 * This function allows you to add directories, which contain 'overlays'
294 * for the active config, that will never be committed.
295 */
296 extern int uci_add_history_path(struct uci_context *ctx, const char *dir);
297
298 /**
299 * uci_revert: revert all changes to a config item
300 * @ctx: uci context
301 * @p: pointer to a uci_package struct ptr (will be replaced by the revert)
302 * @section: section name (optional)
303 * @option option name (optional)
304 */
305 extern int uci_revert(struct uci_context *ctx, struct uci_package **p, const char *section, const char *option);
306
307 /**
308 * uci_parse_argument: parse a shell-style argument, with an arbitrary quoting style
309 * @ctx: uci context
310 * @stream: input stream
311 * @str: pointer to the current line (use NULL for parsing the next line)
312 * @result: pointer for the result
313 */
314 extern int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result);
315
316 /**
317 * uci_set_backend: change the default backend
318 * @ctx: uci context
319 * @name: name of the backend
320 *
321 * The default backend is "file", which uses /etc/config for config storage
322 */
323 extern int uci_set_backend(struct uci_context *ctx, const char *name);
324
325 /**
326 * uci_validate_text: validate a value string for uci options
327 * @str: value
328 *
329 * this function checks whether a given string is acceptable as value
330 * for uci options
331 */
332 extern bool uci_validate_text(const char *str);
333
334 /* UCI data structures */
335 enum uci_type {
336 UCI_TYPE_HISTORY = 0,
337 UCI_TYPE_PACKAGE = 1,
338 UCI_TYPE_SECTION = 2,
339 UCI_TYPE_OPTION = 3,
340 UCI_TYPE_PATH = 4,
341 UCI_TYPE_BACKEND = 5,
342 UCI_TYPE_ITEM = 6,
343 };
344
345 enum uci_option_type {
346 UCI_TYPE_STRING = 0,
347 UCI_TYPE_LIST = 1,
348 };
349
350 enum uci_flags {
351 UCI_FLAG_STRICT = (1 << 0), /* strict mode for the parser */
352 UCI_FLAG_PERROR = (1 << 1), /* print parser error messages */
353 UCI_FLAG_EXPORT_NAME = (1 << 2), /* when exporting, name unnamed sections */
354 UCI_FLAG_SAVED_HISTORY = (1 << 3), /* store the saved history in memory as well */
355 };
356
357 struct uci_element
358 {
359 struct uci_list list;
360 enum uci_type type;
361 char *name;
362 };
363
364 struct uci_backend
365 {
366 struct uci_element e;
367 char **(*list_configs)(struct uci_context *ctx);
368 struct uci_package *(*load)(struct uci_context *ctx, const char *name);
369 void (*commit)(struct uci_context *ctx, struct uci_package **p, bool overwrite);
370
371 /* private: */
372 const void *ptr;
373 void *priv;
374 };
375
376 struct uci_context
377 {
378 /* list of config packages */
379 struct uci_list root;
380
381 /* parser context, use for error handling only */
382 struct uci_parse_context *pctx;
383
384 /* backend for import and export */
385 struct uci_backend *backend;
386 struct uci_list backends;
387
388 /* uci runtime flags */
389 enum uci_flags flags;
390
391 char *confdir;
392 char *savedir;
393
394 /* search path for history files */
395 struct uci_list history_path;
396
397 /* private: */
398 int err;
399 const char *func;
400 jmp_buf trap;
401 bool internal;
402 char *buf;
403 int bufsz;
404 };
405
406 struct uci_package
407 {
408 struct uci_element e;
409 struct uci_list sections;
410 struct uci_context *ctx;
411 bool has_history;
412 char *path;
413
414 /* private: */
415 struct uci_backend *backend;
416 void *priv;
417 int n_section;
418 struct uci_list history;
419 struct uci_list saved_history;
420 };
421
422 struct uci_section
423 {
424 struct uci_element e;
425 struct uci_list options;
426 struct uci_package *package;
427 bool anonymous;
428 char *type;
429 };
430
431 struct uci_option
432 {
433 struct uci_element e;
434 struct uci_section *section;
435 enum uci_option_type type;
436 union {
437 struct uci_list list;
438 char *string;
439 } v;
440 };
441
442 enum uci_command {
443 UCI_CMD_ADD,
444 UCI_CMD_REMOVE,
445 UCI_CMD_CHANGE,
446 UCI_CMD_RENAME,
447 UCI_CMD_LIST_ADD,
448 };
449
450 struct uci_history
451 {
452 struct uci_element e;
453 enum uci_command cmd;
454 char *section;
455 char *value;
456 };
457
458
459 /* linked list handling */
460 #ifndef offsetof
461 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
462 #endif
463
464 /**
465 * container_of - cast a member of a structure out to the containing structure
466 * @ptr: the pointer to the member.
467 * @type: the type of the container struct this is embedded in.
468 * @member: the name of the member within the struct.
469 */
470 #define container_of(ptr, type, member) \
471 ((type *) ((char *)ptr - offsetof(type,member)))
472
473
474 /**
475 * uci_list_entry: casts an uci_list pointer to the containing struct.
476 * @_type: config, section or option
477 * @_ptr: pointer to the uci_list struct
478 */
479 #define list_to_element(ptr) \
480 container_of(ptr, struct uci_element, list)
481
482 /**
483 * uci_foreach_entry: loop through a list of uci elements
484 * @_list: pointer to the uci_list struct
485 * @_ptr: iteration variable, struct uci_element
486 *
487 * use like a for loop, e.g:
488 * uci_foreach(&list, p) {
489 * ...
490 * }
491 */
492 #define uci_foreach_element(_list, _ptr) \
493 for(_ptr = list_to_element((_list)->next); \
494 &_ptr->list != (_list); \
495 _ptr = list_to_element(_ptr->list.next))
496
497 /**
498 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
499 * @_list: pointer to the uci_list struct
500 * @_tmp: temporary variable, struct uci_element *
501 * @_ptr: iteration variable, struct uci_element *
502 *
503 * use like a for loop, e.g:
504 * uci_foreach(&list, p) {
505 * ...
506 * }
507 */
508 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
509 for(_ptr = list_to_element((_list)->next), \
510 _tmp = list_to_element(_ptr->list.next); \
511 &_ptr->list != (_list); \
512 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
513
514 /**
515 * uci_list_empty: returns true if a list is empty
516 * @list: list head
517 */
518 #define uci_list_empty(list) ((list)->next == (list))
519
520 /* wrappers for dynamic type handling */
521 #define uci_type_backend UCI_TYPE_BACKEND
522 #define uci_type_history UCI_TYPE_HISTORY
523 #define uci_type_package UCI_TYPE_PACKAGE
524 #define uci_type_section UCI_TYPE_SECTION
525 #define uci_type_option UCI_TYPE_OPTION
526
527 /* element typecasting */
528 #ifdef UCI_DEBUG_TYPECAST
529 static const char *uci_typestr[] = {
530 [uci_type_backend] = "backend",
531 [uci_type_history] = "history",
532 [uci_type_package] = "package",
533 [uci_type_section] = "section",
534 [uci_type_option] = "option",
535 };
536
537 static void uci_typecast_error(int from, int to)
538 {
539 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
540 }
541
542 #define BUILD_CAST(_type) \
543 static inline struct uci_ ## _type *uci_to_ ## _type (struct uci_element *e) \
544 { \
545 if (e->type != uci_type_ ## _type) { \
546 uci_typecast_error(e->type, uci_type_ ## _type); \
547 } \
548 return (struct uci_ ## _type *) e; \
549 }
550
551 BUILD_CAST(backend)
552 BUILD_CAST(history)
553 BUILD_CAST(package)
554 BUILD_CAST(section)
555 BUILD_CAST(option)
556
557 #else
558 #define uci_to_backend(ptr) container_of(ptr, struct uci_backend, e)
559 #define uci_to_history(ptr) container_of(ptr, struct uci_history, e)
560 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
561 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
562 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
563 #endif
564
565 /**
566 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
567 * @ctx: uci context
568 * @type: {package,section,option}
569 * @name: string containing the name of the element
570 * @datasize: additional buffer size to reserve at the end of the struct
571 */
572 #define uci_alloc_element(ctx, type, name, datasize) \
573 uci_to_ ## type (uci_alloc_generic(ctx, uci_type_ ## type, name, sizeof(struct uci_ ## type) + datasize))
574
575 #define uci_dataptr(ptr) \
576 (((char *) ptr) + sizeof(*ptr))
577
578 #endif