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