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         void *ptr;
  62
  63         ptr = uci_malloc(ctx, size + strlen(name) + 1);
  64         e = (struct uci_element *) ptr;
  65         e->type = type;
  66         e->name = (char *) ptr + size;
  67         strcpy(e->name, name);
  68         uci_list_init(&e->list);
  69
  70         return e;
  71 }
  72
  73 static void
  74 uci_free_element(struct uci_element *e)
  75 {
  76         if (!uci_list_empty(&e->list))
  77                 uci_list_del(&e->list);
  78         free(e);
  79 }
  80
  81 static struct uci_option *
  82 uci_alloc_option(struct uci_section *s, const char *name, const char *value)
  83 {
  84         struct uci_package *p = s->package;
  85         struct uci_context *ctx = p->ctx;
  86         struct uci_option *o;
  87
  88         o = uci_alloc_element(ctx, option, name, strlen(value) + 1);
  89         o->value = uci_dataptr(o);
  90         o->section = s;
  91         strcpy(o->value, value);
  92         uci_list_add(&s->options, &o->e.list);
  93
  94         return o;
  95 }
  96
  97 static inline void
  98 uci_free_option(struct uci_option *o)
  99 {
 100         uci_free_element(&o->e);
 101 }
 102
 103 static struct uci_section *
 104 uci_alloc_section(struct uci_package *p, const char *type, const char *name)
 105 {
 106         struct uci_context *ctx = p->ctx;
 107         struct uci_section *s;
 108         char buf[16];
 109
 110         if (!name || !name[0]) {
 111                 snprintf(buf, 16, "cfg%d", p->n_section);
 112                 name = buf;
 113         }
 114
 115         s = uci_alloc_element(ctx, section, name, strlen(type) + 1);
 116         s->type = uci_dataptr(s);
 117         s->package = p;
 118         strcpy(s->type, type);
 119         uci_list_init(&s->options);
 120         uci_list_add(&p->sections, &s->e.list);
 121
 122         return s;
 123 }
 124
 125 static void
 126 uci_free_section(struct uci_section *s)
 127 {
 128         struct uci_element *o, *tmp;
 129
 130         uci_foreach_element_safe(&s->options, tmp, o) {
 131                 uci_free_option(uci_to_option(o));
 132         }
 133         uci_free_element(&s->e);
 134 }
 135
 136 static struct uci_package *
 137 uci_alloc_package(struct uci_context *ctx, const char *name)
 138 {
 139         struct uci_package *p;
 140
 141         p = uci_alloc_element(ctx, package, name, 0);
 142         p->ctx = ctx;
 143         uci_list_init(&p->sections);
 144         uci_list_init(&p->history);
 145         return p;
 146 }
 147
 148 static void
 149 uci_free_package(struct uci_package *p)
 150 {
 151         struct uci_element *e, *tmp;
 152
 153         if(!p)
 154                 return;
 155
 156         if (p->path)
 157                 free(p->path);
 158         uci_foreach_element_safe(&p->sections, tmp, e) {
 159                 uci_free_section(uci_to_section(e));
 160         }
 161         uci_free_element(&p->e);
 162 }
 163
 164 /* record a change that was done to a package */
 165 static inline void
 166 uci_add_history(struct uci_context *ctx, struct uci_package *p, int cmd, char *section, char *option, char *value)
 167 {
 168         struct uci_history *h = (struct uci_history *) uci_malloc(ctx, sizeof(struct uci_history));
 169
 170         uci_list_init(&h->list);
 171         h->cmd = cmd;
 172         h->section = section;
 173         h->option = option;
 174         h->value = value;
 175         uci_list_add(&p->history, &h->list);
 176 }
 177
 178
 179 static struct uci_element *uci_lookup_list(struct uci_context *ctx, struct uci_list *list, const char *name)
 180 {
 181         struct uci_element *e;
 182
 183         uci_foreach_element(list, e) {
 184                 if (!strcmp(e->name, name))
 185                         return e;
 186         }
 187         return NULL;
 188 }
 189
 190 int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *p, char *section, char *option)
 191 {
 192         struct uci_element *e;
 193         struct uci_section *s;
 194         struct uci_option *o;
 195
 196         UCI_HANDLE_ERR(ctx);
 197         UCI_ASSERT(ctx, res != NULL);
 198         UCI_ASSERT(ctx, p != NULL);
 199         UCI_ASSERT(ctx, section != NULL);
 200
 201         e = uci_lookup_list(ctx, &p->sections, section);
 202         if (!e)
 203                 goto notfound;
 204
 205         if (option) {
 206                 s = uci_to_section(e);
 207                 e = uci_lookup_list(ctx, &s->options, option);
 208         }
 209
 210         *res = e;
 211         return 0;
 212
 213 notfound:
 214         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 215         return 0;
 216 }
 217
 218 int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value)
 219 {
 220         int size;
 221         char *str;
 222         struct uci_list *list;
 223         struct uci_element *e;
 224
 225         UCI_HANDLE_ERR(ctx);
 226         UCI_ASSERT(ctx, value != NULL);
 227         UCI_ASSERT(ctx, element != NULL);
 228         UCI_ASSERT(ctx, *element != NULL);
 229
 230         /* what the 'value' of an element means depends on the type
 231          * for a section, the 'value' means its type
 232          * for an option, the 'value' means its value string
 233          * when changing the value, shrink the element to its actual size
 234          * (it may have been allocated with a bigger size, to include
 235          *  its buffer)
 236          * then duplicate the string passed on the command line and
 237          * insert it into the structure.
 238          */
 239         e = *element;
 240         list = e->list.prev;
 241         switch(e->type) {
 242         case UCI_TYPE_SECTION:
 243                 size = sizeof(struct uci_section);
 244                 break;
 245         case UCI_TYPE_OPTION:
 246                 size = sizeof(struct uci_option);
 247                 break;
 248         default:
 249                 UCI_THROW(ctx, UCI_ERR_INVAL);
 250                 break;
 251         }
 252
 253         uci_list_del(&e->list);
 254         e = uci_realloc(ctx, e, size);
 255         str = uci_strdup(ctx, value);
 256         uci_list_insert(list, &e->list);
 257         *element = e;
 258
 259         switch(e->type) {
 260         case UCI_TYPE_SECTION:
 261                 uci_to_section(e)->type = value;
 262                 break;
 263         case UCI_TYPE_OPTION:
 264                 uci_to_option(e)->value = value;
 265                 break;
 266         default:
 267                 break;
 268         }
 269
 270         return 0;
 271 }
 272
 273 int uci_set(struct uci_context *ctx, char *package, char *section, char *option, char *value)
 274 {
 275         struct uci_element *e;
 276         struct uci_package *p = NULL;
 277         struct uci_section *s = NULL;
 278         struct uci_option *o = NULL;
 279         struct uci_history *h;
 280
 281         UCI_HANDLE_ERR(ctx);
 282         UCI_ASSERT(ctx, package != NULL);
 283         UCI_ASSERT(ctx, section != NULL);
 284
 285         /*
 286          * look up the package, section and option (if set)
 287          * if the section/option is to be modified and it is not found
 288          * create a new element in the appropriate list
 289          */
 290         e = uci_lookup_list(ctx, &ctx->root, package);
 291         if (!e)
 292                 goto notfound;
 293
 294         p = uci_to_package(e);
 295         e = uci_lookup_list(ctx, &p->sections, section);
 296         if (!e)
 297                 goto notfound;
 298
 299         s = uci_to_section(e);
 300         if (option) {
 301                 e = uci_lookup_list(ctx, &s->options, option);
 302                 if (!e)
 303                         goto notfound;
 304                 o = uci_to_option(e);
 305         }
 306
 307         /*
 308          * no unknown element was supplied, assume that we can just update
 309          * an existing entry
 310          */
 311         if (o)
 312                 e = &o->e;
 313         else
 314                 e = &s->e;
 315
 316         uci_add_history(ctx, p, UCI_CMD_CHANGE, section, option, value);
 317         return uci_set_element_value(ctx, &e, value);
 318
 319 notfound:
 320         /*
 321          * the entry that we need to update was not found,
 322          * check if the search failed prematurely.
 323          * this can happen if the package was not found, or if
 324          * an option was supplied, but the section wasn't found
 325          */
 326         if (!p || (!s && option))
 327                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 328
 329         /* now add the missing entry */
 330         uci_add_history(ctx, p, UCI_CMD_ADD, section, option, value);
 331         if (s)
 332                 uci_alloc_option(s, option, value);
 333         else
 334                 uci_alloc_section(p, value, section);
 335
 336         return 0;
 337 }
 338
 339 int uci_unload(struct uci_context *ctx, struct uci_package *p)
 340 {
 341         struct uci_element *e;
 342
 343         UCI_HANDLE_ERR(ctx);
 344         UCI_ASSERT(ctx, p != NULL);
 345
 346         uci_free_package(p);
 347         return 0;
 348 }
 349