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         uci_free_element(&o->e);
 106 }
 107
 108 static struct uci_section *
 109 uci_alloc_section(struct uci_package *p, const char *type, const char *name)
 110 {
 111         struct uci_context *ctx = p->ctx;
 112         struct uci_section *s;
 113         char buf[16];
 114
 115         if (!name || !name[0]) {
 116                 snprintf(buf, 16, "cfg%d", p->n_section);
 117                 name = buf;
 118         }
 119
 120         s = uci_alloc_element(ctx, section, name, strlen(type) + 1);
 121         s->type = uci_dataptr(s);
 122         s->package = p;
 123         strcpy(s->type, type);
 124         uci_list_init(&s->options);
 125         uci_list_add(&p->sections, &s->e.list);
 126
 127         return s;
 128 }
 129
 130 static void
 131 uci_free_section(struct uci_section *s)
 132 {
 133         struct uci_element *o, *tmp;
 134
 135         uci_foreach_element_safe(&s->options, tmp, o) {
 136                 uci_free_option(uci_to_option(o));
 137         }
 138         uci_free_element(&s->e);
 139 }
 140
 141 static struct uci_package *
 142 uci_alloc_package(struct uci_context *ctx, const char *name)
 143 {
 144         struct uci_package *p;
 145
 146         p = uci_alloc_element(ctx, package, name, 0);
 147         p->ctx = ctx;
 148         uci_list_init(&p->sections);
 149         uci_list_init(&p->history);
 150         return p;
 151 }
 152
 153 static void
 154 uci_free_package(struct uci_package *p)
 155 {
 156         struct uci_element *e, *tmp;
 157
 158         if(!p)
 159                 return;
 160
 161         if (p->path)
 162                 free(p->path);
 163         uci_foreach_element_safe(&p->sections, tmp, e) {
 164                 uci_free_section(uci_to_section(e));
 165         }
 166         uci_free_element(&p->e);
 167 }
 168
 169 /* record a change that was done to a package */
 170 static inline void
 171 uci_add_history(struct uci_context *ctx, struct uci_package *p, int cmd, char *section, char *option, char *value)
 172 {
 173         struct uci_history *h;
 174         int size = 0;
 175         char *ptr;
 176
 177         h = uci_alloc_element(ctx, history, option, strlen(section) + strlen(value) + 2);
 178         ptr = uci_dataptr(h);
 179         h->cmd = cmd;
 180         h->section = strcpy(ptr, section);
 181         ptr += strlen(ptr) + 1;
 182         h->value = strcpy(ptr, value);
 183         uci_list_add(&p->history, &h->e.list);
 184 }
 185
 186 static struct uci_element *uci_lookup_list(struct uci_context *ctx, struct uci_list *list, const char *name)
 187 {
 188         struct uci_element *e;
 189
 190         uci_foreach_element(list, e) {
 191                 if (!strcmp(e->name, name))
 192                         return e;
 193         }
 194         return NULL;
 195 }
 196
 197 int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *p, char *section, char *option)
 198 {
 199         struct uci_element *e;
 200         struct uci_section *s;
 201         struct uci_option *o;
 202
 203         UCI_HANDLE_ERR(ctx);
 204         UCI_ASSERT(ctx, res != NULL);
 205         UCI_ASSERT(ctx, p != NULL);
 206         UCI_ASSERT(ctx, section != NULL);
 207
 208         e = uci_lookup_list(ctx, &p->sections, section);
 209         if (!e)
 210                 goto notfound;
 211
 212         if (option) {
 213                 s = uci_to_section(e);
 214                 e = uci_lookup_list(ctx, &s->options, option);
 215         }
 216
 217         *res = e;
 218         return 0;
 219
 220 notfound:
 221         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 222         return 0;
 223 }
 224
 225 int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value)
 226 {
 227         bool internal = ctx->internal;
 228         struct uci_list *list;
 229         struct uci_element *e;
 230         struct uci_package *p;
 231         struct uci_section *s;
 232         char *section;
 233         char *option;
 234         char *str;
 235         int size;
 236
 237         UCI_HANDLE_ERR(ctx);
 238         UCI_ASSERT(ctx, value != NULL);
 239         UCI_ASSERT(ctx, element != NULL);
 240         UCI_ASSERT(ctx, *element != NULL);
 241
 242         /* what the 'value' of an element means depends on the type
 243          * for a section, the 'value' means its type
 244          * for an option, the 'value' means its value string
 245          * when changing the value, shrink the element to its actual size
 246          * (it may have been allocated with a bigger size, to include
 247          *  its buffer)
 248          * then duplicate the string passed on the command line and
 249          * insert it into the structure.
 250          */
 251         e = *element;
 252         list = e->list.prev;
 253         switch(e->type) {
 254         case UCI_TYPE_SECTION:
 255                 size = sizeof(struct uci_section);
 256                 s = uci_to_section(e);
 257                 section = e->name;
 258                 option = NULL;
 259                 break;
 260         case UCI_TYPE_OPTION:
 261                 size = sizeof(struct uci_option);
 262                 s = uci_to_option(e)->section;
 263                 section = s->e.name;
 264                 option = e->name;
 265                 break;
 266         default:
 267                 UCI_THROW(ctx, UCI_ERR_INVAL);
 268                 return 0;
 269         }
 270         p = s->package;
 271         if (!internal)
 272                 uci_add_history(ctx, p, UCI_CMD_CHANGE, section, option, value);
 273
 274         uci_list_del(&e->list);
 275         e = uci_realloc(ctx, e, size);
 276         str = uci_strdup(ctx, value);
 277         uci_list_insert(list, &e->list);
 278         *element = e;
 279
 280         switch(e->type) {
 281         case UCI_TYPE_SECTION:
 282                 uci_to_section(e)->type = str;
 283                 break;
 284         case UCI_TYPE_OPTION:
 285                 uci_to_option(e)->value = str;
 286                 break;
 287         default:
 288                 break;
 289         }
 290
 291         return 0;
 292 }
 293
 294 int uci_set(struct uci_context *ctx, char *package, char *section, char *option, char *value)
 295 {
 296         struct uci_element *e;
 297         struct uci_package *p = NULL;
 298         struct uci_section *s = NULL;
 299         struct uci_option *o = NULL;
 300         struct uci_history *h;
 301         bool internal = ctx->internal;
 302
 303         UCI_HANDLE_ERR(ctx);
 304         UCI_ASSERT(ctx, package != NULL);
 305         UCI_ASSERT(ctx, section != NULL);
 306         UCI_ASSERT(ctx, value != NULL);
 307
 308         /*
 309          * look up the package, section and option (if set)
 310          * if the section/option is to be modified and it is not found
 311          * create a new element in the appropriate list
 312          */
 313         e = uci_lookup_list(ctx, &ctx->root, package);
 314         if (!e)
 315                 goto notfound;
 316
 317         p = uci_to_package(e);
 318         e = uci_lookup_list(ctx, &p->sections, section);
 319         if (!e)
 320                 goto notfound;
 321
 322         s = uci_to_section(e);
 323         if (option) {
 324                 e = uci_lookup_list(ctx, &s->options, option);
 325                 if (!e)
 326                         goto notfound;
 327                 o = uci_to_option(e);
 328         }
 329
 330         /*
 331          * no unknown element was supplied, assume that we can just update
 332          * an existing entry
 333          */
 334         if (o)
 335                 e = &o->e;
 336         else
 337                 e = &s->e;
 338
 339         if (!internal)
 340                 return uci_set_element_value(ctx, &e, value);
 341
 342         UCI_INTERNAL(uci_set_element_value, ctx, &e, value);
 343         return 0;
 344
 345 notfound:
 346         /*
 347          * the entry that we need to update was not found,
 348          * check if the search failed prematurely.
 349          * this can happen if the package was not found, or if
 350          * an option was supplied, but the section wasn't found
 351          */
 352         if (!p || (!s && option))
 353                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 354
 355         /* now add the missing entry */
 356         if (!internal)
 357                 uci_add_history(ctx, p, UCI_CMD_ADD, section, option, value);
 358         if (s)
 359                 uci_alloc_option(s, option, value);
 360         else
 361                 uci_alloc_section(p, value, section);
 362
 363         return 0;
 364 }
 365
 366 int uci_unload(struct uci_context *ctx, struct uci_package *p)
 367 {
 368         struct uci_element *e;
 369
 370         UCI_HANDLE_ERR(ctx);
 371         UCI_ASSERT(ctx, p != NULL);
 372
 373         uci_free_package(p);
 374         return 0;
 375 }
 376