major code refactoring for more code reuse and smaller code size
[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 /*
19 * you can use these defines to enable debugging behavior for
20 * apps compiled against libuci:
21 *
22 * #define UCI_DEBUG_TYPECAST:
23 * enable uci_element typecast checking at run time
24 *
25 */
26
27
28 #include <setjmp.h>
29 #include <stdio.h>
30
31 #define UCI_CONFDIR "/etc/config"
32
33 enum
34 {
35 UCI_OK = 0,
36 UCI_ERR_MEM,
37 UCI_ERR_INVAL,
38 UCI_ERR_NOTFOUND,
39 UCI_ERR_IO,
40 UCI_ERR_PARSE,
41 UCI_ERR_UNKNOWN,
42 UCI_ERR_LAST
43 };
44
45 struct uci_list
46 {
47 void *next;
48 void *prev;
49 };
50
51 struct uci_package;
52 struct uci_section;
53 struct uci_option;
54 struct uci_history;
55 struct uci_parse_context;
56
57
58 /**
59 * uci_alloc: Allocate a new uci context
60 */
61 extern struct uci_context *uci_alloc(void);
62
63 /**
64 * uci_free: Free the uci context including all of its data
65 */
66 extern void uci_free(struct uci_context *ctx);
67
68 /**
69 * uci_perror: Print the last uci error that occured
70 * @ctx: uci context
71 * @str: string to print before the error message
72 */
73 extern void uci_perror(struct uci_context *ctx, const char *str);
74
75 /**
76 * uci_import: Import uci config data from a stream
77 * @ctx: uci context
78 * @stream: file stream to import from
79 * @name: (optional) assume the config has the given name
80 * @package: (optional) store the last parsed config package in this variable
81 *
82 * the name parameter is for config files that don't explicitly use the 'package <...>' keyword
83 */
84 extern int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package);
85
86 /**
87 * uci_export: Export one or all uci config packages
88 * @ctx: uci context
89 * @stream: output stream
90 * @package: (optional) uci config package to export
91 */
92 extern int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package);
93
94 /**
95 * uci_load: Parse an uci config file and store it in the uci context
96 *
97 * @ctx: uci context
98 * @name: name of the config file (relative to the config directory)
99 * @package: store the loaded config package in this variable
100 */
101 extern int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package);
102
103 /**
104 * uci_unload: Unload a config file from the uci context
105 *
106 * @ctx: uci context
107 * @name: name of the config file
108 */
109 extern int uci_unload(struct uci_context *ctx, const char *name);
110
111 /**
112 * uci_cleanup: Clean up after an error
113 *
114 * @ctx: uci context
115 */
116 extern int uci_cleanup(struct uci_context *ctx);
117
118 /**
119 * uci_list_configs: List available uci config files
120 *
121 * @ctx: uci context
122 */
123 extern char **uci_list_configs(struct uci_context *ctx);
124
125 /* UCI data structures */
126 enum uci_type {
127 UCI_TYPE_PACKAGE,
128 UCI_TYPE_SECTION,
129 UCI_TYPE_OPTION
130 };
131
132 struct uci_element
133 {
134 struct uci_list list;
135 enum uci_type type;
136 char *name;
137 };
138
139 struct uci_context
140 {
141 /* list of config packages */
142 struct uci_list root;
143
144 /* parser context, use for error handling only */
145 struct uci_parse_context *pctx;
146
147 /* private: */
148 int errno;
149 jmp_buf trap;
150 char *buf;
151 int bufsz;
152 };
153
154 struct uci_parse_context
155 {
156 /* error context */
157 const char *reason;
158 int line;
159 int byte;
160
161 /* private: */
162 struct uci_package *package;
163 struct uci_section *section;
164 FILE *file;
165 const char *name;
166 char *buf;
167 int bufsz;
168 };
169
170 struct uci_package
171 {
172 struct uci_element e;
173 struct uci_list sections;
174 struct uci_context *ctx;
175 /* private: */
176 int n_section;
177 };
178
179 struct uci_section
180 {
181 struct uci_element e;
182 struct uci_list options;
183 struct uci_package *package;
184 char *type;
185 };
186
187 struct uci_option
188 {
189 struct uci_element e;
190 struct uci_section *section;
191 char *value;
192 };
193
194 enum uci_command {
195 UCI_CMD_ADD,
196 UCI_CMD_REMOVE,
197 UCI_CMD_CHANGE
198 };
199
200 struct uci_history
201 {
202 struct uci_list list;
203 enum uci_command cmd;
204 union {
205 struct uci_element element;
206 struct uci_package package;
207 struct uci_section section;
208 struct uci_option option;
209 } data;
210 };
211
212 /* linked list handling */
213 #ifndef offsetof
214 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
215 #endif
216
217 /**
218 * container_of - cast a member of a structure out to the containing structure
219 * @ptr: the pointer to the member.
220 * @type: the type of the container struct this is embedded in.
221 * @member: the name of the member within the struct.
222 */
223 #define container_of(ptr, type, member) \
224 ((type *) ((char *)ptr - offsetof(type,member)))
225
226
227 /**
228 * uci_list_entry: casts an uci_list pointer to the containing struct.
229 * @_type: config, section or option
230 * @_ptr: pointer to the uci_list struct
231 */
232 #define element_to(type, ptr) \
233 container_of(ptr, struct uci_ ## type, e)
234
235 #define list_to_element(ptr) \
236 container_of(ptr, struct uci_element, list)
237
238 /**
239 * uci_foreach_entry: loop through a list of uci elements
240 * @_list: pointer to the uci_list struct
241 * @_ptr: iteration variable, struct uci_element
242 *
243 * use like a for loop, e.g:
244 * uci_foreach(&list, p) {
245 * ...
246 * }
247 */
248 #define uci_foreach_element(_list, _ptr) \
249 for(_ptr = list_to_element((_list)->next); \
250 &_ptr->list != (_list); \
251 _ptr = list_to_element(_ptr->list.next))
252
253 /**
254 * uci_foreach_entry_safe: like uci_foreach_safe, but safe for deletion
255 * @_list: pointer to the uci_list struct
256 * @_tmp: temporary variable, struct uci_element *
257 * @_ptr: iteration variable, struct uci_element *
258 *
259 * use like a for loop, e.g:
260 * uci_foreach(&list, p) {
261 * ...
262 * }
263 */
264 #define uci_foreach_element_safe(_list, _tmp, _ptr) \
265 for(_ptr = list_to_element((_list)->next), \
266 _tmp = list_to_element(_ptr->list.next); \
267 &_ptr->list != (_list); \
268 _ptr = _tmp, _tmp = list_to_element(_ptr->list.next))
269
270 /* returns true if a list is empty */
271 #define uci_list_empty(list) ((list)->next == (list))
272
273 /* element typecasting */
274 #ifdef UCI_DEBUG_TYPECAST
275 static const char *uci_typestr[] = {
276 [UCI_TYPE_PACKAGE] = "package",
277 [UCI_TYPE_SECTION] = "section",
278 [UCI_TYPE_OPTION] = "option"
279 }
280
281 static void uci_typecast_error(int from, int to)
282 {
283 fprintf(stderr, "Invalid typecast from '%s' to '%s'\n", uci_typestr[from], uci_typestr[to]);
284 }
285
286 #define BUILD_CAST(type, val) \
287 static inline struct uci_ ## type *uci_to_ ## type (struct uci_element *e) \
288 { \
289 if (e->type != val) { \
290 uci_typecast_error(e->type, val); \
291 } \
292 return (struct uci_ ## type *) e; \
293 }
294
295 BUILD_CAST(package, UCI_TYPE_PACKAGE)
296 BUILD_CAST(section, UCI_TYPE_SECTION)
297 BUILD_CAST(option, UCI_TYPE_OPTION)
298
299 #else
300 #define uci_to_package(ptr) container_of(ptr, struct uci_package, e)
301 #define uci_to_section(ptr) container_of(ptr, struct uci_section, e)
302 #define uci_to_option(ptr) container_of(ptr, struct uci_option, e)
303 #endif
304
305 /**
306 * uci_alloc_element: allocate a generic uci_element, reserve a buffer and typecast
307 * @ctx: uci context
308 * @type: {package,section,option}
309 * @name: string containing the name of the element
310 * @datasize: additional buffer size to reserve at the end of the struct
311 */
312 #define uci_alloc_element(ctx, type, name, datasize) \
313 uci_to_ ## type (uci_alloc_generic(ctx, name, sizeof(struct uci_ ## type) + datasize))
314
315 #define uci_dataptr(ptr) \
316 (((char *) ptr) + sizeof(*ptr))
317
318 #endif