some helpful comments
[project/uci.git] / list.c
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 #include <glob.h>
16
17 /* initialize a list head/item */
18 static inline void uci_list_init(struct uci_list *ptr)
19 {
20 ptr->prev = ptr;
21 ptr->next = ptr;
22 }
23
24 /* inserts a new list entry after a given entry */
25 static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
26 {
27 list->next->prev = ptr;
28 ptr->prev = list;
29 ptr->next = list->next;
30 list->next = ptr;
31 }
32
33 /* inserts a new list entry at the tail of the list */
34 static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
35 {
36 /* NB: head->prev points at the tail */
37 uci_list_insert(head->prev, ptr);
38 }
39
40 static inline void uci_list_del(struct uci_list *ptr)
41 {
42 struct uci_list *next, *prev;
43
44 next = ptr->next;
45 prev = ptr->prev;
46
47 prev->next = next;
48 next->prev = prev;
49
50 uci_list_init(ptr);
51 }
52
53 /*
54 * uci_alloc_generic allocates a new uci_element with payload
55 * payload is appended to the struct to save memory and reduce fragmentation
56 */
57 static struct uci_element *
58 uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size)
59 {
60 struct uci_element *e;
61 int datalen = size;
62 void *ptr;
63
64 if (name)
65 datalen += strlen(name) + 1;
66 ptr = uci_malloc(ctx, datalen);
67 e = (struct uci_element *) ptr;
68 e->type = type;
69 if (name) {
70 e->name = (char *) ptr + size;
71 strcpy(e->name, name);
72 }
73 uci_list_init(&e->list);
74
75 return e;
76 }
77
78 static void
79 uci_free_element(struct uci_element *e)
80 {
81 if (!uci_list_empty(&e->list))
82 uci_list_del(&e->list);
83 free(e);
84 }
85
86 static struct uci_option *
87 uci_alloc_option(struct uci_section *s, const char *name, const char *value)
88 {
89 struct uci_package *p = s->package;
90 struct uci_context *ctx = p->ctx;
91 struct uci_option *o;
92
93 o = uci_alloc_element(ctx, option, name, strlen(value) + 1);
94 o->value = uci_dataptr(o);
95 o->section = s;
96 strcpy(o->value, value);
97 uci_list_add(&s->options, &o->e.list);
98
99 return o;
100 }
101
102 static inline void
103 uci_free_option(struct uci_option *o)
104 {
105 if ((o->value != uci_dataptr(o)) &&
106 (o->value != NULL))
107 free(o->value);
108 uci_free_element(&o->e);
109 }
110
111 static struct uci_section *
112 uci_alloc_section(struct uci_package *p, const char *type, const char *name)
113 {
114 struct uci_context *ctx = p->ctx;
115 struct uci_section *s;
116 char buf[16];
117
118 if (!name || !name[0]) {
119 snprintf(buf, 16, "cfg%d", p->n_section);
120 name = buf;
121 }
122
123 s = uci_alloc_element(ctx, section, name, strlen(type) + 1);
124 s->type = uci_dataptr(s);
125 s->package = p;
126 strcpy(s->type, type);
127 uci_list_init(&s->options);
128 uci_list_add(&p->sections, &s->e.list);
129
130 return s;
131 }
132
133 static void
134 uci_free_section(struct uci_section *s)
135 {
136 struct uci_element *o, *tmp;
137
138 uci_foreach_element_safe(&s->options, tmp, o) {
139 uci_free_option(uci_to_option(o));
140 }
141 if ((s->type != uci_dataptr(s)) &&
142 (s->type != NULL))
143 free(s->type);
144 uci_free_element(&s->e);
145 }
146
147 static struct uci_package *
148 uci_alloc_package(struct uci_context *ctx, const char *name)
149 {
150 struct uci_package *p;
151
152 p = uci_alloc_element(ctx, package, name, 0);
153 p->ctx = ctx;
154 uci_list_init(&p->sections);
155 uci_list_init(&p->history);
156 return p;
157 }
158
159 static void
160 uci_free_package(struct uci_package *p)
161 {
162 struct uci_element *e, *tmp;
163
164 if(!p)
165 return;
166
167 if (p->path)
168 free(p->path);
169 uci_foreach_element_safe(&p->sections, tmp, e) {
170 uci_free_section(uci_to_section(e));
171 }
172 uci_free_element(&p->e);
173 }
174
175 /* record a change that was done to a package */
176 static void
177 uci_add_history(struct uci_context *ctx, struct uci_package *p, int cmd, char *section, char *option, char *value)
178 {
179 struct uci_history *h;
180 int size = strlen(section) + 1;
181 char *ptr;
182
183 if (!p->confdir)
184 return;
185
186 if (value)
187 size += strlen(section) + 1;
188
189 h = uci_alloc_element(ctx, history, option, size);
190 ptr = uci_dataptr(h);
191 h->cmd = cmd;
192 h->section = strcpy(ptr, section);
193 if (value) {
194 ptr += strlen(ptr) + 1;
195 h->value = strcpy(ptr, value);
196 }
197 uci_list_add(&p->history, &h->e.list);
198 }
199
200 static void
201 uci_free_history(struct uci_history *h)
202 {
203 if (!h)
204 return;
205 if ((h->section != NULL) &&
206 (h->section != uci_dataptr(h))) {
207 free(h->section);
208 free(h->value);
209 }
210 uci_free_element(&h->e);
211 }
212
213 static struct uci_element *uci_lookup_list(struct uci_context *ctx, struct uci_list *list, const char *name)
214 {
215 struct uci_element *e;
216
217 uci_foreach_element(list, e) {
218 if (!strcmp(e->name, name))
219 return e;
220 }
221 return NULL;
222 }
223
224 int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *p, char *section, char *option)
225 {
226 struct uci_element *e;
227 struct uci_section *s;
228 struct uci_option *o;
229
230 UCI_HANDLE_ERR(ctx);
231 UCI_ASSERT(ctx, res != NULL);
232 UCI_ASSERT(ctx, p != NULL);
233 UCI_ASSERT(ctx, section != NULL);
234
235 e = uci_lookup_list(ctx, &p->sections, section);
236 if (!e)
237 goto notfound;
238
239 if (option) {
240 s = uci_to_section(e);
241 e = uci_lookup_list(ctx, &s->options, option);
242 }
243
244 *res = e;
245 return 0;
246
247 notfound:
248 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
249 return 0;
250 }
251
252 int uci_del_element(struct uci_context *ctx, struct uci_element *e)
253 {
254 /* NB: UCI_INTERNAL use means without history tracking */
255 bool internal = ctx->internal;
256 struct uci_package *p = NULL;
257 struct uci_section *s = NULL;
258 struct uci_option *o = NULL;
259 struct uci_element *i, *tmp;
260 char *option = NULL;
261
262 UCI_HANDLE_ERR(ctx);
263 UCI_ASSERT(ctx, e != NULL);
264
265 switch(e->type) {
266 case UCI_TYPE_SECTION:
267 s = uci_to_section(e);
268 uci_foreach_element_safe(&s->options, tmp, i) {
269 uci_del_element(ctx, i);
270 }
271 break;
272 case UCI_TYPE_OPTION:
273 o = uci_to_option(e);
274 s = o->section;
275 p = s->package;
276 option = e->name;
277 break;
278 default:
279 UCI_THROW(ctx, UCI_ERR_INVAL);
280 break;
281 }
282
283 p = s->package;
284 if (!internal)
285 uci_add_history(ctx, p, UCI_CMD_REMOVE, s->e.name, option, NULL);
286
287 switch(e->type) {
288 case UCI_TYPE_SECTION:
289 uci_free_section(s);
290 break;
291 case UCI_TYPE_OPTION:
292 uci_free_option(o);
293 break;
294 default:
295 break;
296 }
297 return 0;
298 }
299
300 int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value)
301 {
302 /* NB: UCI_INTERNAL use means without history tracking */
303 bool internal = ctx->internal;
304 struct uci_list *list;
305 struct uci_element *e;
306 struct uci_package *p;
307 struct uci_section *s;
308 char *section;
309 char *option;
310 char *str;
311 int size;
312
313 UCI_HANDLE_ERR(ctx);
314 UCI_ASSERT(ctx, value != NULL);
315 UCI_ASSERT(ctx, element != NULL);
316 UCI_ASSERT(ctx, *element != NULL);
317
318 /* what the 'value' of an element means depends on the type
319 * for a section, the 'value' means its type
320 * for an option, the 'value' means its value string
321 * when changing the value, shrink the element to its actual size
322 * (it may have been allocated with a bigger size, to include
323 * its buffer)
324 * then duplicate the string passed on the command line and
325 * insert it into the structure.
326 */
327 e = *element;
328 list = e->list.prev;
329 switch(e->type) {
330 case UCI_TYPE_SECTION:
331 size = sizeof(struct uci_section);
332 s = uci_to_section(e);
333 section = e->name;
334 option = NULL;
335 break;
336 case UCI_TYPE_OPTION:
337 size = sizeof(struct uci_option);
338 s = uci_to_option(e)->section;
339 section = s->e.name;
340 option = e->name;
341 break;
342 default:
343 UCI_THROW(ctx, UCI_ERR_INVAL);
344 return 0;
345 }
346 p = s->package;
347 if (!internal)
348 uci_add_history(ctx, p, UCI_CMD_CHANGE, section, option, value);
349
350 uci_list_del(&e->list);
351 e = uci_realloc(ctx, e, size);
352 str = uci_strdup(ctx, value);
353 uci_list_insert(list, &e->list);
354 *element = e;
355
356 switch(e->type) {
357 case UCI_TYPE_SECTION:
358 uci_to_section(e)->type = str;
359 break;
360 case UCI_TYPE_OPTION:
361 uci_to_option(e)->value = str;
362 break;
363 default:
364 break;
365 }
366
367 return 0;
368 }
369
370 int uci_del(struct uci_context *ctx, struct uci_package *p, char *section, char *option)
371 {
372 /* NB: pass on internal flag to uci_del_element */
373 bool internal = ctx->internal;
374 struct uci_element *e;
375 struct uci_section *s = NULL;
376 struct uci_option *o = NULL;
377
378 UCI_HANDLE_ERR(ctx);
379 UCI_ASSERT(ctx, p != NULL);
380 UCI_ASSERT(ctx, section != NULL);
381
382 UCI_INTERNAL(uci_lookup, ctx, &e, p, section, option);
383
384 if (!internal)
385 return uci_del_element(ctx, e);
386 UCI_INTERNAL(uci_del_element, ctx, e);
387
388 return 0;
389 }
390
391 int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value)
392 {
393 /* NB: UCI_INTERNAL use means without history tracking */
394 bool internal = ctx->internal;
395 struct uci_element *e = NULL;
396 struct uci_section *s = NULL;
397 struct uci_option *o = NULL;
398 struct uci_history *h;
399
400 UCI_HANDLE_ERR(ctx);
401 UCI_ASSERT(ctx, p != NULL);
402 UCI_ASSERT(ctx, section != NULL);
403 UCI_ASSERT(ctx, value != NULL);
404
405 /*
406 * look up the package, section and option (if set)
407 * if the section/option is to be modified and it is not found
408 * create a new element in the appropriate list
409 */
410 UCI_INTERNAL(uci_lookup, ctx, &e, p, section, NULL);
411 s = uci_to_section(e);
412 if (option) {
413 e = uci_lookup_list(ctx, &s->options, option);
414 if (!e)
415 goto notfound;
416 o = uci_to_option(e);
417 }
418
419 /*
420 * no unknown element was supplied, assume that we can just update
421 * an existing entry
422 */
423 if (o)
424 e = &o->e;
425 else
426 e = &s->e;
427
428 if (!internal)
429 return uci_set_element_value(ctx, &e, value);
430
431 UCI_INTERNAL(uci_set_element_value, ctx, &e, value);
432 return 0;
433
434 notfound:
435 /*
436 * the entry that we need to update was not found,
437 * check if the search failed prematurely.
438 * this can happen if the package was not found, or if
439 * an option was supplied, but the section wasn't found
440 */
441 if (!p || (!s && option))
442 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
443
444 /* now add the missing entry */
445 if (!internal)
446 uci_add_history(ctx, p, UCI_CMD_ADD, section, option, value);
447 if (s)
448 uci_alloc_option(s, option, value);
449 else
450 uci_alloc_section(p, value, section);
451
452 return 0;
453 }
454
455 int uci_unload(struct uci_context *ctx, struct uci_package *p)
456 {
457 struct uci_element *e;
458
459 UCI_HANDLE_ERR(ctx);
460 UCI_ASSERT(ctx, p != NULL);
461
462 uci_free_package(p);
463 return 0;
464 }
465